US2419476A - Winding control means for magnetic recording and reproducing apparatus - Google Patents

Description

s. J. BEGUN 2,419,476

WINDING CONTROL MEANS FOR MAGNETIC RECORDING AND REPRODUCING APPARATUS April 22 .1947.

Filed Jan. 31, 1946 4 Sheets-Sheet 1- mvmron. S. J. BEGU N P M.

ATTORNEYS S. J. BEGUN A ril 22 19470 WINDING CONTROL MEANS FOR MAGNETIC RECORDING AND REPRODUCING APPARATUO Filed Jan. 31, 1946 4 Sheets-Sheet 2 I. [Ill-Ill! "/l/l/Il/l, I 'IIIIII I INVENTOR. S.J. BEGUM ATTORNEYS Aprifi @2 1947. 2,419,476 WINDING CONTROL MEANS FOR MAGNETIC aficoanme AND nsrnopucme APPARATUS 5. J. azsuu Filed Jan. 31, 1946 4 Sheets-Sheet 3 mmvros. $.J. Besuu BY f ATTORNEYS Apsrfifi 22 1194?. s. J, @EGUN 2,419,,76

WINDING CONTROL MEANS FOR mcma'nc RECORDING AND REPRODUCING APPARATUS Filed Jan. 31, 1946 4 Sheets-Shoat 4 INVENTOR. S. J. Bzeuu ATTORNEYS Y 34m v Patented Apr. 22, 1947 WINDING CONTROL MEANS FOR MAGNETIC RECORDING AND REPRODUCING APPA- RATUS.

Semi Joseph Begun, Cleveland Heights, Ohio, as-

signor to Magnetone, Inc., Cleveland, Ohio, a

corporation of Ohio Application January 31, 1946, Serial No. 644,600

14 Claims.

This application is in part a continuation of application Serial No. 499,795, filed August 24,

This invention relates to magnetic recording and reproducing apparatus, and more particularly to such apparatus utilizing asa magnetic recording medium a thin flexible magnetic record member, such as a wire, filament or tape which may be stored on reels for carrying on magnetic recording and reproducing operations.

Among the objects of the invention are novel magnetic recording devices of the foregoing type embodying various features which make them foolproof and simple in operation and which eliminate difilculties heretofore encountered with such devices.

The foregoing and other objects of the invention will be best understood from the following description of exemplifications thereof, reference being had to the accompanying drawings wherein Fig. 1 is a simplified diagrammatic view illustrating the general relationship of the mechanical, magnetic and electric elements of a magnetic recording and reproducing apparatus exemplifying the invention;

Fig. 1A is a diagrammatic view similar to Fig. 1 of a modified form of drive control arrangement based on the principles of the invention;

Fig. 1B is a diagrammatic view similar to Fig. 1A of another drive control arrangement exemplifying the invention;

Figs. 1C and 1D are generally diagrammatic side and plan views of a modified form of drive control arrangement for a magnetic recorder of the type shown in Fig. 1;

Fig. l-E is a perspective view of some of the elements of the control arrangement shown in Figs. 1C and 1--D;

Fig. 2 is a diagrammatic view and circuit diagram of another recorder of the invention; and

Fig. 3 shows a detailed view of part of the control arrangement of the recorder of Fig. 2, being a section along line 3-3 of Fig. 2.

Fig. 1 illustrates in a simplified diagrammatic manner the general relationship of the mechanical, magnetic and electric elements of a magnetic recording and reproducing apparatus exemplifying the principles of the invention. A magnetic recording medium in the form of a thin flexible magnetic record member, such as a magnetic record wire, filament or wire-like tape 3|, is arranged to be reeled on'take-up reel 33 from supply reel 34, which are shown In the specific arrangement as seen in Fig. 1,'

magnetic recording and reproducing operations are carried on when the recording medium 3| is impelled in the forward direction indicated by arrow 3|A by driving and rotating reel 33 in counterclockwise direction looking from below Fig. 1. In order to play back the recorded program or to make a new record on the recordin medium 3|, it must be rewound on the supply reel 34 which is then driven and rotated in clockwise direction, as seen from below Fig. 1, the directions in which the two reels are driven being indicated by arrows applied to the schematically indicated brake drums 22| associated with the two reels 33, 34, respectively.

In moving from one reel toward the other, the recording medium 3| is guided through a magnetic 'record transducer head structure 36 which operates to magnetically record, play back as well as erase the signals recorded on the recording medium 3|. In the particular arrangement shown, the transducer head is also utilized .for level winding the recording medium on the reel on which it is reeled. The transducer head structure 36 is not part of the invention and may be of any type.

In order to simplify the description of the circuits by means of which the recording, playback and erasing operations are performed, the elements of the transducer .head structure 36 are also indicated in the circuit diagram of Fig. 1 by a dash-line rectangle 36--A, and is there shown provided with an erasing head 31 and a record transducing head 38. Each of the heads 31, 38 is shown provided with windings and a magnetic core structure which has pole pieces separated by a non-magnetic. gap past which the recording medium 3| is moving in the direction of the arrow 3|A. The recording medium 3| is guided through the transducer head structure so that during the recording operation each element of the recording medium passes successively first past the gap region of the erasing of different contact positions, the numeral I to 5 applied to some of the contact positions indicating the different contact positions of the selector switch 40. Contact blades 40-| to 40-3 of the selector switch 40 establish the recording circuits when the contact blades are in position I and they establish the playback circuits when the contact blades are in position 2.

When the selector switch is in the recording to which is also connected the negative terminals of all D. 0. supply sources.

The high frequency erasing current supplied by the oscillator 4| to the erasing head 31 is of sufficiently large amplitude so that each longitudinal element of the thin moving magnetic recording medium 3|, passing the gap region of the erasing head 31, is subjected to an alternating flux strong enough to erase any previous magnetic signal records of the moving medium and restore the magnetic elements thereof to a magnetically neutral condition. After being subjected to the magnetic erasing action by the erasing head 31, each element of the moving recording medium 3|, upon reaching the gap region of the record transducing head 38, is subjected to a magnetic recording flux produced by the amplified signal currents which are to be recorded and a superimposed high frequency biasing flux component.

In Fig. 1, a conventionally shown microphone 42 serves as a source of the signals which are to be recorded and a reproducing device, such as a loudspeaker 45 serves to reproduce the signals. During a recording operation, the microphone is connected by way of contact blade 40-| to the input side of an amplifier 43, the output of which is supplied by way of contact blade 40-2 of the selector switch to the windings of the recording head 38 which records the signals, the circuits being completed by the ground connections shown. The high frequency bias component of the recording flux is provided by a high frequency current component derived from the oscillator 4| by a circuit, such as shown, which includes an adjustable coupling condenser 44 for supplying an adjustable component of the high frequency oscillations to the output circuit of the amplifier 43 where it is mixed with the amplified signal currents and supplied to the windings of the transducer head 38 which records the signals. The coupling condenser 44 and the other circuit elements of the system are designed to mix a suitable component of the high frequency oscillations derived from the oscillator 4| with the amplified signal current supplied by the microphone in such manner as to produce in the gap region of the recording head 38 the desired combination of ,the signal recording flux and the superimposed high frequency biasing flux component. I

In general, when recording signals of the audible frequency range, good results are obtained by using a high frequency biasing flux of about 25 kilocycles per second and the same small high frequency biasing component to the recording head 38.

To play back the magnetically recorded signa while the recording medium is moving in the same direction as during the recording process, the selector switch 40 is actuated to the play a position 2. When the selector switch is in the playback position 2, its contact blade 40-3 disconnects the oscillator 4| from the source of power supply. thereby de-energizing the oscillator, and no high frequency erasing or biasing currents are supplied to the erasing head 31 and the transducer head 38. Furthermore, selector contact blades 40-I, 40-2 now connect the windings of the record transducer head 38, which operates now as a playback head, to the input side of the amplifier 43, the output of which is now supplied after amplification in an additional amplifier stage 43-A to the reproducing device 45 for reproducing the signals.

In the magnetic recording device shown in Fig. 1, the two reels 33, 34 with the recording medium stored thereon form part of a self-supporting detachable guide unit 2-| 0 designed for detachable interconnection with a motor or drive unit 4-|0. The drive unit 4-|0 is shown in the form of a casing in which are housed all the elements of the driving mechanism as well as the amplifier and the principal control elements of the device, and supplies the mechanical power required for reeling the magnetic recording medium from one reel to the other.

The drive mechanism of the drive unit 4-l0 has a drive motor 4-20 which may be provided with a built-in speed reducing mechanism so as to drive a motor drive shaft 4-22 at a speed at which it may be directly coupled to the drive shaft 4|3 of the take-up reel 33 for driving it at the speed proper for carrying on recording or reproducing operations. The driving mechanism of the recording device shown is so designed as to assure that when one of the reels 33, 34 is driven for reeling thereon the recording medium, the other reel will at all times be subjected to a braking action sufficient to maintain the recording medium under tension, and that when the direction of the motion of the recording medium is reversed, the removal of the driving forces from one reel and the application to the other reel is controlled in a predetermined time sequence to assure that the two reels and the moving recording medium are first brought to a positive stop before the driving forces are applied to the other reel. The selective application of the driving forces to each reel is interlocked and subjected to the control of time action means so that whenever the application of the driving forces is reversed, the reel mechanism is first brought to a positive stop before the driving forces are applied to the other reel.

In the arrangement shown, the drive control mechanism includes coupling means, generally designated 4-30, for selectively coupling the mosource of high frequency signals may be used for tor drive shaft 4-22 either directly to reel drive shaft 4-l 3 or through a speed step-up mechanism to the other reel drive shaft 4-|4 for driving the supply reel 34 in clockwise direction at an increased speed during the rewinding operation.

In the arrangement shown, the coupling means comprise slidably mounted coupling members 43|, 4-32 which are operated by a coupling lever 4-35 from the position shown in which coupling member 4-3I establishes a direct coupling connection between the motor drive shaft 4-22 and the reel drive shaft 4-|3 of the takeup reel 33 for rotating it in forward directionor to the opposite coupling position indicated by dash-dot lines 4-35-Ib-in which coupling member 4-3l breaks the coupling connection from the motor drive shaft 4-22 to the drive shaft 4-13 of the take-up reel, and instead couples the motor drive shaft 4-22 to gear 4-36 of a train of step-up gears including gear 4-31, while the other coupling member 4-32, which is now in reverse coupling condition, couples the gear 4-31 to th rewind drive shaft 4-l4 for rotating the supply reel at a higher speed in clockwise direction.

The control lever 4-35 is shown pivotally mounted on a fixed pivot 4-4l and one end thereof is connected through a pivot pin 4-44 to a spring-loaded toggle arm 4-43, the other end of which is pivotally held on a fixed pivot 4-45. The toggle arm 4-43 is formed of two telescopically mounted sliding toggle arm sections, the ends of which are biased apart by a compression spring 4-46 so that when the coupling lever 4-35 is moved past a center position, its toggle arm 443 with its compression spring 4-46 will bring the coupling lever either to the forward coupling position shown or to the opposite rewind coupling position indicated by dash line 4-35-R.

The coupling mechanism of the type described may be controlled either mechanically or electrically. In order to provide for remote control, the coupling mechanism shown is electrically controlled. In the form shown, the electrical control comprises two relay or solenoid members 53-F, 53-R held in fixed position and having core or armature members which are pivotally interconnected to moving portions of the coupling lever so that when the forward solenoid 53-F is energized, the coupling lever 4-35 will be actuated from the dotted line position 4-35-R to the full line position shown, and that when the rewind solenoid 53-3. is energized, the coupling lever will be actuated to the dash-line position 4-35-R.

The drive control mechanism shown is arranged to utilize only a single timeaction means for assuring that whenever the drive control mechanism is actuated from either one or the other drive position to a standby position or to the opposite drive position, the time action means are actuated to make it impossible to establish the opposite drive connection until after a predetermined time action suflicient to assure that the reels have. been brought to a stop before the opposite drive connection could be established, if the drive control mechanism is actuated to the opposite drive control position.

Fig. 1 illustrates in a simplified diagrammatic manner one form of such drive control arrangement. It utilizes as a time action means a single time delay relay 6|, which is arranged to open its contacts 62 instantaneously upon the de-energization of the relay and to reclose with a desired time delay when the relay is energized, or, in other words, to instantaneously open a control circuit and to close the control circuit with a required time delay. The desired time action of relay 6| is supplied by a circuit including a condenser 63 and a resistor 64 interconnected with a condenser charging circuit which is controlled in such manner that the time required for charging the condenser to a predetermined potential determines the time delay with which relay 6i operates.

:In the arrangement shown, the charging current to the condenser 63 is controlled by an electron tube 65 having an anode as well as a cathode 61 and a control grid 60. The positive terminal of a supply source indicated by 3+ is connected to the anode of tube 65, the cathode 61 being connected through the winding of relay ti and resistor 10, the circuit being completed by charged by current flowing through the tube so as to apply to the control grid 68 a potential which causes the tube to pass suiiicient current for energizing-the relay 6| and cause it to keep its contacts 62 closed as long as no negative blocking potential is applied to the control grid 68 of tube 65.v

.The arrangement is such that when a negative blocking potential is applied to the control grid 68 of the tube, the current flow through the winding of relay 6| will bestopped or reduced and cause it to instantaneously open its contacts 02. The condenser 63 and the resistor 64 are someportioned and interconnected with the other circuit elements associated with tube 65 that when the negative blocking potential is removed from control grid 68, the required time delay will elapse before the current flow is able to charge up the condenser 63 through the resistor 64 to the proper potential at which the control or bias applied to the control grid 68 enables the tube to send through the winding-of relay 6| a current suflicient for actuating the relay to close its contacts 62.

In the arrangement shown, the blocking potential is applied to the control grid 68 of tube 65 by the operation of the selector switch 40 which is utilized to control the recording, playback as well as the rewinding operations. -Selector contact blade 40-4 applies a negative blocking potential to the control grid 68 whenever it is moved to or past position 3 from either one of its other positions I, 2 or 4, 5. As a result, the relay opens each time the selector switch 40 is moved either from positions I and 2 to position 3 or from po. sitions 5 and 4 to position 3, or from either one of positions I and 2 to either one of positions 4 and 5, or vice versa.

As explained above, the reversal of the driving connection to the reels or, in general, to the impelling elements which impel the recording medium, is controlled by the operation of the selector switch 40 and particularly by its set of contact blades 40-3, 40-4 40-5. The drive control circuits also include a normally closed forward limit switch 5l-F which opens whenever the limit of the forward reeling motion is,

and open positions, to the operative positions shown when the coupling lever, or, in general,

the coupling means, are actuated to establish a forward drive coupling connection and a set of similar switches 56-R, 51-R which are operated from the normally biased positions shown to the operative positions when the coupling means are actuated to establish rewind driving connections. In the arrangement shown, the switches 56-F, Eli-R. control the selective en ergization and de-energization of the two coupling solenoids 55-F and 53-R so as to deenergize a solenoid after it has been energized and has performed a drive reversal operation. The two other switches 51-F, l-R control the energization of the drive motor 4-20 and operate to permit energization of the motor only when the drive reversing operation has reached a, predetermined stage at which the energization and driving action of the motor are desirable.

In particular, the two sets of switches are shown controlled by a finger plate 4-49 suitably afixed to the control lever 4-35 so as to move therewith and is provided with two sets of fingers 4-41, 4-48 for operating the two sets of coupling control switches 56-F, 51-F, 56-R, 5l-R. The switches iii-F, 51-F, Eli-R, til-R as well as the similar other switches shown are of the micro-switch type which operate with a snap action when actuated by a push pin or similar actuating element. In the arrangement shown, the several switches which are operated by the control lever 4-35, or, in general, the coupling control means, are designed to operate in the following manner:

It is assumed that the drive mechanism is in the condition shownoin which the coupling mechanism establishes the driving connection from the motor 4-20 to forward drive reel shaft 4-I3. In the arrangement shown, the reversal of the drive connection is controlled by the selective closure of the contacts of either the forward drive relay 55-F or rewind drive relay 55-R, which also serve to control the energization of the motor. The two auxiliary relays 55-F, 55-R perform merely the auxiliary function of making it possible to separate the power line circuits which supply operating power for the motor 4-20 and the coupling solenoids 53-F, 53-13. from the operating circuits which are used for remotely controlling the operation of the drive mechanism and the recording and reproducing operations from low power relay supply sources which are indicated in the diagram by the plus sign connected to switch blade 40-5 and ground connection.

With the mechanism in the condition shown, when the contacts of rewind relay 55-R are closed, current will be sent from one terminal of a source of power supply indicated by a double plus sign through the closed coupling intel-locked contacts 56-R, and through the rewind solenoid 53-R, the energized circuit of which is completed only if the time delay relay 6| closes its contacts which connect the circuit to the other terminal of the power supply indiwill start moving the coupling lever 4-35 from the coupling position shown toward the dash-dot line position 4-35-12. The two coupling interlock switches 56-R, 5l-R which are operated by the control lever as it moves towards the rewind coupling position are arranged to be actuated in a predetermined sequence in order to assure that the motor energizing switch 51-R operates to energize the motor before the coupling member 4-32 has established coupling engagement with-the coupling teeth of the coupling member 4-32-R through which it is coupled to the rewind drive shaft 4-, and that the coupling interlock switch 56-R shall operate to open and de-energize the rewind solenoid 53-R I after the coupling teeth of coupling elements 4-32, 4-32-R are suificiently engaged and the coupling lever is past the over-center position. The other set of coupling interlock switches 56-F, 5I-F are arranged to operate in an analogous manner when the forward solenoid 53-F is energized to operate the coupling mechanism 1 to reverse the drive connection from rewind to forward drive.

With the foregoing arrangement, the drive mechanism will drive the recording medium in forward direction whenever the contacts of forward relay 55-1 are closed, provided the coupling mechanism is in the forward coupling position. Similarly, the driving mechanism will drive the recording medium in the rewind direction whenever the contacts of rewind relay 55-R are closed, provided the coupling mechanism is in the rewind coupling position indicated by the dash-dot line 4-35-R.

Since the circuits controlled by the forward drive relay 55-F and rewind relay 55-R serve also to control the operation of the coupling reversing solenoids 53-F, 53-R, the selective energization of either of the contacts of one or the other of the drive control relays 55-F, 55-R will also bring about a reversal of the coupling connections if one or the other of the relay contacts is actuated to the closed position for driving the recording medium in one direction while the coupling mechanism is in a position in which it establishes a driving connection in the other direction.

Thus, if the drive mechanism is in the condition shown in Fig. 1 in which the drive shaft of motor 4-20 is coupled to the drive shaft 4-13 of the take-up reel for driving it in forward direction, and the contacts of the rewind relay 55-R. are actuated to the closed position, it will complete a circuit leading by way of the closed coupling interlock contacts 56-5. to the solenoid 53-R bringing about its energization, provided the contacts of the time delay relay iii are closed; whereupon, the rewind solenoid 53-R will be operated to reverse the coupling connection from the pQ ition shown to the position corresponding to the rewind drive position indicated by the dash-dot line 4-35-R. When so actuated to the rewind position, the movement of the coupling mechanism automatically operates the interlock contacts 56-R, 5'l-R to successively energize the motor and de-energize the rewind solenoid 53-R as it reaches the rewind coupling position of dash-dot line 4-35-R.

In other words, the circuit leading to the two selectively operating contacts of the forward drive relay 55-F and the rewind drive relay 55-3 may be directly utilized for controlling the'operation of the drive mechanism to start and stop the driving action in one or the other direction or to at any time reverse the driving motion, in which case, however, the operation of the time action means 6| delays the reversal of the driving connections until the mechanism has been brought to a stop. In the arrangement shown, the seleccontact blade 40-5 which is connected to one.

terminal of the relay supply source, through the winding of the forward drive relay 55-F, through the contacts of the forward limit switch I-F to the normally closed contacts of the latch switch,

53, and then through a common circuit portion leading to the contacts of contact positions 2, 4, 5 of the selector contact blade 40-4 to which there is also connected the drive operating switch 58 which is shown used to set the drive mechanism in motion for forward drive during a recording operation.

Thus, with the arrangement shown, the forward drive relay 55-F will be energized and operated whenever the contact blades 40-5, 40-4 are in the playback position 2 and also when they are in the recording position, in which case, however, the operation of the forward relay 55-F to start and stop the' drive will be controlled by the push-button drive switch 58 which may be combined with a microphone so that the person recording may stop the recording operation and start the recording operation as he transmits with the microphone the desired message.

In an analogous manner, the rewind drive relay 55-R will be energized to operate its contacts and cause the recording medium to be rewound whenever the selector contact blades 40-4, 40-5 are in either positions 4 to 5. It will be noted' that when the selector switch 40 with its drive control blades is actuated from either one of positions I, 2 to either one of positions 4, 5, or vice versa, contact blade 40-4, on reaching or moving past the standby position 3, applies a blocking potential to he control circuit of time delayrelay 6|, thereby instantaneously causing it to open its contacts and ole-energize the operating circuits of both coupling solenoids. Because of the time delay action in reclosing its contacts, the time delay relay 6| will keep the energizing circuits of the coupling solenoids 53-F, 53-R de-energized for the time required in order to bring the motor to a stop, in all cases when the selector switch 40 has been actuated from either one of the forward drive positions I, 2 to either one of the rewind positions 4, 5, or vice versa.

It will be noted that whenever the selector switch blade 40-4 is in the standby position 3 or is returned to the standby position 3 from any of the drive positions, it will apply a blocking potential to the control circuit of the time delay relay 6| and instantaneously release its contacts to its normally open position in which it deenergizes the coupling reversing solenoids 53-F, 53-R.

The arrangement of the type described above makes it possible to discontinue at any time a recording or playback operation and start a re 10 winding operation by moving the selector switch from either one of positions I, 2 to either one of positions 4, 5, in which case the rewind operation will be started after the time delay provided by the time action of the time action relay 0|. In a similar way, a rewind operation may be discontinued at any time and changed over to a recording or playback operation by moving the selector switch from any one of positions 4, 5 to any one of positions I, 2, in which case the forward drive will be started after the time delay provided by the time action relay 6| to assure that the recording medium and the reels have, been first brought to a stop before starting to move in reverse direction.

It will be noted that with the drive mechanism in the forward drive position shown, actuation of the selector switch from the standby position to any one of the forward drive positions I, 2 will start the forward drive at once, without any time delay. Similarly, in the event the drive coupling connection has been previously reversed to estab lish the rewind connections indicated by dash-dot line 4-35-R, a rewind operation will be started instantaneously without any time delay by merely moving the selector switch from the standby position to any one of the rewind positions 4, 5.

The contact blades of the selector switch 40, in addition to performing in their different operating positions the various functions described above, are also utilized to perform additional operations interlinked with their operations thus far described. Thus, in the recording position I of the selector switch, selector switch blade 40-3 applies the full positive potential to the oscillator 4| for energizing it to supply the erasing as well as the biasing currents, while at the same time the source of positive supply which is connected to this selector switch blade is also connected through a voltage reducing resistance 13 to the screen grid of a tube of the additional amplifier stage 43-A, thereby reducing the anode current drain of this amplifier stage without in any way impairing the operation of the principal amplifier 43 which serves to amplify the signal currents which are supplied to the recording head 38.

However, in the playback position 2 as well as in the rewind position 4, the selector switch blade 40-3 applies the full positive potential to the screen grid of the additional amplifier stage 43-A so that the auxiliary amplifier 43-A operates with full efllcien-cy to amplify the recorded signals reproduced by the transducer head 38 now operating as a playback head to secure eflicient reproduction of the record by reproducing device 45. In the arrangement shown, the record playback process is also carried on during the rewinding operation for playing back the recorded signal sequence in reverse direction, This is desirable in many applications, because with a little experience, a user of such recording device will be able to distinguish and recognize from the scrambled sequence of the recorded signals played back during a rewinding operation one or another part of the previously recorded message which he desires to playback. In such case, he has merely to stop the rewinding operation and actuate the selector switch 40 to play back the desired sequence. In order to provide for the playback operation during the rewinding process, selector switch blades 40-I, 40-2 complete in contact position 4 the same playback circuits which they established in position 2, as described above.

Furthermore, selector switch blade 40-l applies a ground connection to the input side of the amplifier 43 when the selector switch is in the standby position or in the special rewinding position which may be utilized for subjecting the recording medium to a special erasing operation, for instance, to erasure by 9, direct current supplied to the recording head, in which case the positive terminal of a suitable direct current source is connected to the contact element of contact position 5 of selector switch blade 48-22 Instead of using time action means using electric circuit elements for determining the time delay, such as described above in connection with the time delay relay 6 l, other forms of time action means may be used. Thus, for instance, a spring driven member, such as an arm of a springdriven clock work, may be used as the timing element for interposing a required time delay each time a drive control action is performed for reversing the direction of the drive forces applied to the recording medium or a drive control action which might be followed by an action which results in the reversal of the driving forces applied to the recording medium, so as to prevent reversal of the driving forces applied to the recording medium before the recording medium is first brought to a stop.

Such modified time action means may be combined with a relay, such as relay 6i shown in Fig. 1, so that the time action means operates to reclose the relay contacts with the required time delay, the relay contacts and the timing mechanism being combined so that whenever the relay winding is energized the contacts open instantaneously and at the same time cause the time action means to be charged for performing the desired timing action. Such time action relay means operating with a spring-driven timing mechanism are well known in the art and need not here be described. A relay 6| combined with such time action means may be controlled in the same manner as described above so that each time the selector switch is operated from a forward drive or rewind drive position to the standby position, the relay BI is energized to instantaneously open its contacts, the contacts bei g re-.

closed under the control of the time action means with the required time delay for restoring the conditions under which a reversal of the driving connection or, in general, a reversal of the application of the driving forces to the recording medium may be accomplished.

Instead of using a contact blade of a selector switch, such as selector blade 48-4, for actuating the time action means to block a reversal of the driving connection each time the selector switch is actuated to reverse the driving connections, the time action means may be arranged to be operated each time the selector switch is moved from one control position to another control position for interposing a timed preventive action which prevents a reversal of the driving connection or, in general, a reversal of the driving forces applied to the recording medium until the end of the timing interval necessary to assure the stopping of the recording medium.

In Fig. l-A is shown-one form of such modified drive control arrangement in which conventional time action means are instantaneously actuated to the blocking condition in which it prevents the drive mechanism from completing a drive reversing operation during a predeterminated time delay, whenever the drive control means such as selector switch 48, shown in Fig. 1, is actuated from any one of its operating to another oper- 12 ating condition. The rotary shaft of the selector switch 40 which carries the various contact blades 48-l to 48-5 has also secured thereto an actuating member shown in the form of a cam sector 81 provided with a plurality of cam projections 82 arranged so that whenever the contact blades of the selector switch are moved'from one position to the other, one or another of the cam pro- .iections operates a suitably mounted switch 88. As indicated in Fig. 1A, the switch 83 serves to control the operation of time action means to instantaneously disable the drive reversing mechanism. for the duration of a predetermined timing interval required to assure that upon performing a drive reversing operation, the recording medium is brought to a stop before driving forces are applied thereto in opposite direction.

As explained above the time action means may be a mechanically timed mechanism which is indicated in Fig. l-A as a dash-pot relay iii-l arranged to instantaneously open its contacts 6 i-2 upon energization of the relay and to reclose its contacts after a predeterminated adjustably set timing period following the re-energization of the relay.

The contacts 6l-2 of the time action relay Gl-i may be connected in the control circuit leadin from one terminal of an electric power source to the two coupling solenoids 53-F, 53-R so that each time the time action relay iii-l is energised, it instantaneously opens its contacts iii-2 thereby disabling the coupling reversing mechanism for the period of the required timing interval.

Alternatively, the cam projections 82 of the drive control selector means 48 may be utilized for operating a mechanical latch member to interlockingly engage and lock a mechanical element of the coupling mechanism each time such drive control selector is actuated from one operating position to the other, the time action means permitting the return of the latch member to the coupling releasing position only after the lapse of the required timing interval.

Instead of using a rotary drive control selector means of the type indicated in Figs. 1 and l-A, push-button type control selector means may be used for controlling the operation of the drive mechanism. Fig. 1B shows a conventional type push-button mechanism which may be utilized for performing the control actions of a rotary selector of the type described in connection with Figs. 1 and l-A. The selector mechanism ,of Fig. 1B may be provided with five push rods, only two of which are indicated at 85-4, 85-5, for performing the control actions performed by the selector contact blades 48-4 and 48-5 of Fig. 1. The push rods 85-4, 85-5 are slidably guided in guide slits or holes of spaced mounting bars 86 which are joined by two cross bars 81 into a substantially rigid frame work. Each push rod is biased by a biasing spring 88 to thhe normal released position in which rod 85-4 is shown. Furthermore, each push rod is provided with a laterally projecting cam-like latch projection 89 and passes through a longitudinal slit 9| of a latch .bar 80, slidably mounted in slits or holes of the cross bar 81 of the frame work so that when anyone of the push rods is actuated from the released position to the operative position shown occupied by rod 85-5 the cam projection of the actuated push rod will laterally displace or shift the latch bar to release all other push rods, such as push rod -5 which is in the latch position,

the latch bar '30 being returned by its biasing spring 33 to the latching position shown, thereby locking the operated push rod in the operated position.

A selector control mechanism of the type shown in Fig. 1-13 may be provided with several sets of switches 95 one for each push rod and arranged so that when a push rod is actuated to the operated positions shown occupied by push rod 85-5, it will actuate its set of switches to the operative position. The sets of switches operated by the several push rods of Fig. l-B may be'utilized to perform the circuit control operations which are performed in Fig. 1 by selector switch blades 40-l to 40-5.

The selector mechanism of the type shown in Fig. l-B is also shown provided with additional switch contacts 83-l suitably supported on the frame work so that the switch 83-l is operated by the lateral movement of the push rod 90 each time one or the other of the push buttons 85-! to 85-5 is actuated to the operative position. The additional switch 83-l may be utilized for controlling the time action means such as relay 6 I-i in the same manner as it is controlled by the switch contacts 83 of the control mechanism shown in Fig. l-A for disabling the drive reversing mechanism during a. predetermined timing interval, each time the drive control means is actuated from one operating condition to another operating condition. The mechanical motion of the individual push rods of a selector mechanism of the type shown in Fig. l-B may be utilized for mechanically controlling the drive or the coupling mechanism of the type described above in .turn it to the coupling release position after a required time delay.

In Fig. l-B each set of switches 95 is shown provided with releasable switch contacts 95-4 and 95-5 which are closed only for a short instance when the associated push rod is actuated and pushed inwardly to the operated position at The end of its inward stroke, the switch contacts 95-5 being released to the open position when the push rod is returned to the latch bar 90 at the level at which it holds the other switch contacts closed,

in the manner shown in Fig. l-B for the upper set of switches 95 of operated push rod 85-5. The releasable switch contacts 95-5 of the several sets of switches may be connected inparallel and used in lieu of the additional switch 83-l for momentarily energizing the time action relay 6| each time one of the several push rods is operated to effect a drive control operation.

In Figs. 1-C to l-E is shown a modified form of drive control arrangement of the general type described in connection with 1. It has a coupling mechanism similar to that of Fig. 1, a coupling lever 4-35 serves to establish forwarddrive coupling connections in the full line position shown, and is movable therefrom to the' dash-dot line position 4-35-R, in which it esiii) tablishes a rewind drive coupling connections during the rewinding operation. The coupling lever 4-35 is biased by a toggle arm 4-43 either to the forward-drive full line position or to the 14 rewind drive dash-pot position 4-35-R in the manner described in connection with Fig. 1. However, instead of operating the coupling control lever -435 through by solenoids it is operated manually by means of a control lever HI pivotly mounted on a fixed pivot H2, and movable between the full line position shown-to which it is brought for actuating the coupling mechanism to the forward-drive coupling position-and the dash-dot line position Ill-A to which it is brought for actuating the coupling mechanism to the rewind-drive coupling position.

As indicated in Figs. 1-0 and 1-D the control lever III is connected to a movable portion of the coupling lever 4-35 by an energy storing connector element, shown in the form of a spring H4, so that when the control lever III is moved from the full line position to the dashdot position HIA, the biasing spring H4 will be charged and tensioned so that it exerts a force suiiicient to bring the coupling lever 4-35 from the forward drive full line position shown to the dash-dot line rewind-drive position 4-35-R. The connector spring i i4 is similarly effective in returning the coupling lever 4-35 from the dashdot,rewind-drive position 4-35-R to the forward drive full line position shown when the control lever III is returned from the dash-dot line position lH-R to the full line position Ill.

Means are also provided for retaining or looking the coupling control lever H I and preventing a reversal of the driving forces applied to the recording medium, before first bringing the recording medium to a stop, either in the full line position shown to which it is brought for establishing the forward drive conditions or the dashdot line position I I l-A to which it is brought for establishing the rewind-drive conditions. The locking means are shown in the form of two locking projections H3 held suitably afiixed in the manner indicated in Fig. 1-E along the path of movement of the handle arm lever H I, so'that it may b moved passed the interlocking projections H3. The portion of the control lever III is resiliently flexible so that it may be lifted from its position of locking engagement with a locking projection H3 and moved from one position to the other. The control arm of the control lever IH being biased to establish locking engagement with a locking projection H3 when it is moved beyond it.

The drive control arrangement shown in Figs. l-C and l-E is also combined with time action means operative to prevent a reversal of the application of the driving forces to the recording medium before first stopping the recording medium. In the arrangement shown, there is provided to this end a blocking member '1 i5 which is arranged to be moved into a position in which it blocks the movement of the coupling lever 4-35 from one coupling position to the other whenever the coupling control lever HI is actuated from one control position to the other. The blocking element H4 is combined with time action means operative after the required time delay to retract blocking member H5 from the blocking position to a releasing position in which it permits the coupling lever 4-35 to perform a drive reversing operation under the control of the control lever i H In Figs. l-C and 1-D the blocking member H5 is shown held by one arm of a rocking member I I6 pivotally mounted on-a fixed pivot Ill,

'and carrying on its other arm a cam member H8,

shaped so that when the control lever III is moved from one control position to the other control position a portion thereof will engage the cam member H8 and actuate it to cause the rocker 6 to be rocked to a position in which its blocking member H5 blocks the movement of the coupling lever 4-35 from one position to the, other.

As indicated in Figs. 1-0 and 1-D, the rocker member- I I6 of the blocking mechanism is biased by a spring H9 to a releasing position in which the coupling lever4-35 is free to be moved from one coupling position to the other. In addition, the rocker member has connected thereto time .action means, shown in the form of a dash-pot i24, which permits the blocking member ll! being returned from the blocking position to the coupling release position only after a time delay sufficient to assure that the motor is first brought to a stop, whereupon the coupling mechanism is released to reverse the coupling connection under the action of the biasing connector N4 of the coupling control mechanism. The couplingblocking rocker H6 is also utilized to open the motor energizing circuit each time the drive control mechanism is actuated to reverse the direction of the driving forces applied to the recording medium. In the arrangement shown, this is accomplished by providing a switch I26 connected in the circuit leading from the drive motor 4-20 of the recorder so that each time the drive reversal blocking mechanism is actuated to the blocking condition the motor circuit is opened, the switch I26 being re-closed only after the blocking mechanism such as shown in Figs. 1-0 and 1-D has been returned to its coupling-releasing position shown.

Driving torque is transmitted to the reels through the drive ends of the reel drive shafts 4-I2, 4-!3 and the facing ends of the reel drive shafts 2-I2, 2.-l3. respectively, of the reel holder unit 2-l0 which are provided with coupling elements designed for automatically establishing detachable coupling interconnection between them when the reel holder unit 2-I0 is coupled to the drive unit 4-I0. In the arrangement shown, the two reel drive shafts 2-l2, 2-l3 of the reel holder unit are each provided with tapered splined coupling ends 2-I4 arranged for automatic entry and sliding coupling engagement with internally splined female coupling collars 4-6l which form one end of coupling bellows 4-62, the other end of which is provided with a generally similar mounting collar 4-63 by means of which the coupling bellows 4-62 are affixed to the drive ends of the reel drive shafts 4-I2, 4-l3, respectively. The reels 33, 34 are fixed on the shafts 2-l2, 2|3 which are journalled in a mounting plate 2-42 and in bearing members 2-44 in the detachable unit 2-I 0. The plate 2-42 is mounted on posts 2-4l provided on a base plate 2-H of unit 2-I0, the bearing members 2-44 being also mounted on the base plate. A cover 2-43 is provided for the detachable unit.

As indicated each of the reel drive shafts 2-I 2, 2-l3 is provided with one-way brake means for subjecting it to braking forces tending to oppose the rotation of its reels during the unreeling operation. In the form shown, the braking means of each reel drive shaft 2-l2, 2-l3is formed of two brake arms 2-60, each supported on relatively fixed pivots 2-6I. The other ends of each of the arms 2-60 carry a brake shoe 2-62 which is held pressed against a cylindrical brake surface of a brake drum 2-2l by a biasing spring 16 2-83. one end of which is connected to the free end of one brake arm ,2-60 and the other end of which is connected to the pivot pin 2-6I of the other brake arm. Specifically, the brake shoes 2-62, supported by brake arms 2-60, are carbon blocks diametrically disposed and equally spaced from the location of the reel axis. Since a substantially constant tension is to be maintained on the recording medium during a recording or playback process, the braking system employed in conjunction with each of the reels 33, 34 is operating while the recording medium is being drawn from that reel as supply reel. During such operation the braking action on the take-up reel is non-efiectlve. v

Two guide or aligning pins 4-65 projecting outwardly from and in front of the coupling wall 4- interfit with aligning holes or openings formed in the base wall 2-Il of the guide unit.

As indicated each of the reels 33, 34 is provided along one of its rims with a row of locking teeth 2-53 designed for cooperation with lock levers 2-54 pivotally mounted on suitable brackets extending from the base and subjected to the biasing action of biasing means shown in the form of springs 2-55. The biasing action of the spring urges the locking projection of the lock lever 2-54 to enter between the locking teeth 2-53 of the reel and lock it against rotation. The reel lock levers 2-54 are so positioned within the guide unit as to be automatically engaged by the aligning and guide pins 4-65 and actuated to the unlocking position shown whenever the guide unit is coupled in its aligned position to the drive unit 4-l0.

Furthermore, the proper coupling engagement between the guide or reel holder unit 2-l0 and the drive unit 4-l0 is rendered simple and foolproof by providing one of the coupling walls along which they are intercoupled, and more particularly the coupling wall 4- of the drive unit, with outwardly projecting boundary wall elements 4-61 forming a shelf-like nest or recess into which the guide unit 2-l0 may be readily inserted as it is being brought into coupling interengagement with the drive unit. The height of the boundary walls is less than the height of the guide unit, or, in general, the boundary wall elements of the nest structure are so shaped as to make it possible to grip the guide unit 2-I0 with the fingers when bringing it into the nest for coupling it to the drive unit or when removing it therefrom.

LatchLswitch 53 is operated by the handle 5-l2 shown in an initial latching position. Angular movement of the handle 5-I2 from the initial latching position to a locking position is effected byapplying a forward thrust to the handle tip to release interlock finger 5-l8, biased by means of a biasing spring 5-l9. A counterclockwise traverse of the interlock finger 5-l8 through the interlock finger groove 5-20 is terminated and locked in the slot provided at the extreme end of the interlock finger groove. In the locking position pressure is transferred to the tension bar 5-l'l through motion of a cam 5-l3 within the slot 5-l4 of the slide-plate 5-l6. Through the eccentric motion of the cam within the slot, pressure is transmitted to the slide-plate 5-l6. The handle 5-l2 is pivotally.

supported to the cam 5-l3 by the pin 5-l5. The rounded ends of the'tension bar 5-l1 are passed through the bottom ends of he two latch arms 5-2I and 5-22 pivotally supported on pins 5-50, and 5-5l. Motion of the tension bar unit 2|0. Slots 2-33 and 2-34 of the guide.

unit 2-! permit the entrance of and locking engagement of the latch hooks -52, and 5-53 to the latching studs.

As shown, each of the two latch hooks 5-52 and 5-53, projecting through the slots 2-35 and 2-36 of the forward coupling wall 4-||, are pivotally supported by pins 5-23 and 5-24 passing through the respective latch arms 5-2| and 5-22. A biasing spring 5-25'biases the latch hooks 5-52 and 5-53 angularly towards a latching position. Heel pieces 5-34 and 5-35 prevent movement beyond that position by the arresting springs 5-45, and 5-46,

The splined end of the reel shaft of the supply reel 33, is also utilized as a pinion which drives a gear 2-5| of a level wind shaft 2-52, the two ends of which are revolvably mounted in bearings seated in the base plate 2-H of the guide unit and in its mounting bar 2-42 respectively. The level wind shaft 2-52 is provided with a cross thread, similar to that used in level wind mechanisms of fishing reels, the cross threads being engaged by a coupling pin located in a hub forming part of an arm carrying the transducer head 36, so as to impart to the transducer head a reciprocatory motion for level winding of the recording wire or filament 3| on one or the other of the reels 33, 34 on which it is reeled.

The two limit switches 5l-F, 5l-R are operated by the operating fingers 6 l-F, 6 l-R whenever the layers of the recording medium wound on the reel have reached their limit during the forward reeling or rewinding operation, respectively,

The guide unit 2-| 9 has also similarly mounted therein an additional warning switch 52-W arranged to be operated in a similar manner by operating finger 62-W. A short time before the operation of the limit switch 5|R, a warning is indicated, for instance by the lighting of a signal lamp, that the end of the recording medium is approaching and that the recording or playback process is about to be automatically stopped. Conventional micro-switches are used for the limit switches 5|-F, 5I-R and warning switch 52-W.

Other features of a practical form of magnetic recorder described above are more fully described in the publication of the Bureau of Ships, U. S.

Navy, No, NAVSHIPS 365-1520, entitled Recorder-Reproducer Equipment Model VRW-l, I. C. Instruction Book No. 130.

In Figs. 2 and 3 is shown another exemplification of the invention. A detachable guide unit 40 comprises a rectangular mounting plate 42 and a mounting bar 43 secured to the narrow ends of the mounting plate 42, so as to constitute therewith a self-supporting detachable unit on which are mounted the guide and impelling elements which serve to guide and impel a signal carrier, in the form of a long magnetic steel wire 45, past a magnetic signal transducing head 45 for magnetically recording or reproducing signals.

A cover 41, of sheet metal, which is detachably secured to the mounting bar 43, for instance, forms with the mounting plate 42 a casing which 8 houses all the elements of the gu de unit 40. The magnetic wire carrier 45 is stored in spirallycoiled form on two like reels 49, 50 of non-magnetic material, such as aluminum. In the arrangement shown, each reel 49, 59 is formed of a cylindrical drum member 5| provided with flanges and suitably secured to a reel shaft so as to constitute a substantially rigid unitary structure journalled within the mounting plate 42 and the mounting bar 43.

The guide mechanism for such magnetic carrier transporting and storing arrangement is designed so as to assure that the complete guide and impelling mechanismv is stopped for an instant whenever the direction of the motion of the signal carrier is changed and that in bringing the mechanism to a stop, the signal carrieris at all times maintained under tension.

In the arrangement shown in Fig. 2, brake means are shown in the form of an annular brake rim 58 of sheet metal, for instance, secured, as by welding, to the lower disc 54 of each reel 49, 50 and a brake band 6| faced with a suitable brake lining engaging the brake rim 56. The magnetic head 46 is impelled and guided in an up-and-down transverse movement by an endless cross-threaded leveling screw 12,

The carrier-guide reel holder unit 40, with its wire reels 49, 50 and other elements forming part thereof, is designed for detachable coupling in conditions during the recording or reproducing operation, and also when the guide unit is rerriioved from the motor unit, for storage, or the li e.

As shown in Fig, 2, the motor unit 4| has an upwardly facing coupling wall provided at its two side regions with aligning pins '|8| interfltting with corresponding aligning holes formed in the facing portions of the mounting plate. The guide unit 40 is arranged to be automatically locked in the aligned coupled position on the motor unit 4| when placed on the mounting wall 89, for instance, by two spring arm latches 283 secured to the side walls of the motor unit 4|, and having latch projections 84 overlying and interlockingly engaging the facing end edge portions of the mounting plate 42 within a cut-out provided in the end portions of the mounting bar 43 whichare secured to the mounting plate.

The motor unit 4| is provided with two reel driving shafts I89, I99 suitably mounted therein so that when the reel holder 49 is placed in its aligned coupled position on the motor unit 4| the upwardly biased coupling members 89-|, 9|l-| of the shafts automatically establish drivingcoupling connections with cooperating coupling surface elements 89-2, 99-2 formed on the lower ends of the two reel shafts.

The shaft I89, which serves to rotate the reel 49 when the wire 45 is wound thereon while recording or reproducing, is connected through a suitable speed reduction gearing connection I93 to an additional low-speed wire-leveling shaft 94 suitably supported within the motor unit so that when the reel holder 49 is placed in its operative coupled position on the motor unit 4|, the upwardly biased coupling member 94-'-| of the leveling shaft 94 automatically establishes a driving coupling connection with a cooperating coupling element 94-2 formed in the lower end of the leveling screw 12 so as to impart to the magnetic head 46 the proper up-and-down 19 transverse leveling motion, the rate of which is correlated to the rate at which the wire is wound on one or-the other of the two reels 49, 50.

Automatic indicating mechanism is shown formed of a traveling nut pointer IOI guided longitudinally on two spindles I02, I03 mounted on supporting lugs I04 suitably secured to the mounting plate 42, spindle I02 being rotatable and being provided with a thread so that proper rotation thereof will cause the traveling-nut pointer IM to move along a scale I06 for indicating thereon the progress of the recording or reproducing process, or, in general, of the winding operation.

Means are also provided for actuating the indicating mechanism spindle I02 at the proper rate of speed correlated to the rate at which the wire 45 is being moved from one reel to the other. One end of the threaded indicator spindle I02 is shown connected through a bevelled gear ID! to a bevelled gear I08 of a shaft I09, which is supported in bearings so that by rotating the shaft I09 at the proper rate, the indicator IOI will indicate on the scale I06 the relation of the length of the wire stored on the two reels. The proper rate of rotation may be imparted to the gear I08 and its shaft I09 through an additional indicator drive shaft I interconnected through a, suitable reduction gear 96 with the reel drive shaft I80 and having an upwardly biased coupling element I95I arranged to automatically establish a coupling connection with a coupling end I95-2 formed on the lower end of the shaft section I09 through which the indicator spindle I02 is rotated.

It may also be of advantage to provide the carrier guide unit 00 with built-in corresponding reduction gearing mechanisms Sit-I, 96-! arranged so that the rotation of the reel 29 imparts the required rate of rotation to the level winding screw I2 and to the indicator spindle I02.

. The driving arrangement and the associated control arrangement are designed and correlated that when the direction of the motion of the signal carrier is reversed, the selective application of the driving forces and the braking forces to the two reels is performed in apredetermined timed sequence to assure that the two reels and the carrier stored thereon are first brought to a positive stop by the action of the braking forces as the driving force is removed from one reel and applied to the other.

The driving force may be applied to the two reels either by a single motor, such as an electric motor, or two separate motors. In either case, the application of the driving force to each .reel is interlocked with the application of a braking force thereto so that whenever the driving force is removed, a sufiicient braking force is applied to assure that the reel with the mass of the coiled signal carrier carried thereon is brought to a stop in the required short interval before the driving force is applied to the other reel,

The interlocked application of the driving and braking forces to each reel may be controlled by electrically operated or by mechanically operated elements or by a combination of electrically and mechanically operated elements. In accordance with the invention, the elements governing the controlled interlocked application of the driving and braking forces to each reel are so designed that even in case the electric power, used for providing the mechanical driving forces and the electrical control actions, fails, the two reels with the wire stored thereon will at all times be subjected to sumcient braking forces as to assure that they are brought to and remain stopped and that the signal carrierwound thereon remains under tension.

Fig. 2 illustrates diagrammatically one form of drive arrangement based on the foregoing principles which uses only one electric motor I20. This motor I20 as well as the other electrically actuated elements referred to herein may be either of the conventional A. C. or D. C. type, but in order to simplify the description, they are indicated as being supplied from an electric source designated by and signs.

In the arrangement shown in Fig. 2, the motor I20 is shown driving through a speed reduction gearing, including gears I2I, I22, and I22--I, a

driving gear I23 revolvably mounted on reel shaft I89 for applying counterclockwise rotational driving forces to reel 49 for winding thereon the wire during recording or reproducing. The motor is further connected through a gear 224 to a gear I25 revolvably mounted on the shaft I for applying a clockwise rotational force to reel 50- for rewinding thereon the wire at a higher speed after a recording or reproducing operation, the reel 50 being driven, for instance, at twice the speed reel 49 is driven.

Each of the two reel shafts I89, I90 is provided with means for selectively applying thereto the required rotational driving and the braking force. The gear discs I23, I25 which revolve freely on the two reel shafts are shown fixed against displacement along their shafts. Each of the two reel shafts is also shown provided with a coupling unit 226, I21, respectively, for selectively coupling each shaft either to the associated driving gear I23, I25 or to an associated brake member I28.

Each shaft I80, I90 is shown connected to its coupling member 226, I21 by a key pin I3I extending through the shaft and through a slit I32 of the sleeve-like coupling-member portion slidably mounted on the shaft so as to permit limited slidable movement of the coupling member along the shaft while being fixed thereon against rotation.

Each coupling member 226, I21 has a coupling surface rim I33 provided with a coupling lining movable into coupling engagement with the facing coupling surface of the corresponding driving gear I23, I25 so as to selectively apply their driving forces to the respective reel shafts I89, I90. Each coupling member also has a braking rim I34 provided with a suitable brake lining surface movable in opposite direction into braking engagement with the facing braking surface of a stationary brake member I28 so as to selectively apply a braking force suflicient to promptly stop the rotation of the respective reel shafts.

Each coupling member 226, I21 is shown linked to a pivotally mounted coupling lever I35, which is biased by a spring I31 so as to cause the associated coupling member to be maintained in the braking position, Each coupling member is also shown provided with cam follower projections I4I, the ends of which are shown riding across a ball I42 on a cam surface of a control member I43 mounted for sliding motion from the lefthand position, indicated in Fig. 2, in which the raised portion of its cam surface region I46 presses the coupling surface I33 of the coupling member into coupling engagement with the driving gear I23 for driving reel shaft I89, to the analogous right-hand position, in which the other cam surface region correspondingly raises the 21 other coupling member I21 from its released lower position in which its brake rim I34 is pressed into braking engagement with the associated brake member I28. A suitable resilient element of the required stiffness will be embodied in the connection between the shafts I89, I80 and their respective coupling members, for mstance, in the form of a spring interposed between the lower end of each shaft, and the bottom surtion to the right in a predetermined timed sequence of operations, automatically effects a reversal'of the coupling and braking connections of thetwo reel shafts, the operation of the cam region I44 causing the coupling member 226 to be first returned to the lower positions in which shaft 89 opens its coupling connection to gear I23 and establishes its braking connection with its brake member I28, followed by the operation of the other cam region which raises the other coupling member I21 to its upper position in which shaft I90 opens its braking connection to its braking member I28 and establishes its driving connection to its driving gear I25.

The control member I43 may be actuated to its different operating positions, either manually or by automatic means locally or remotely controlled. Fig.- 2 indicates the principles of one form of the automatic control arrangement. The control I43 has rotatably mounted on a face thereof a cam I46 which is arranged to be continuously rotated, for instance, by a small motor I41--I through a suitable gearing. As also indicated in Fig. 3, two catch pins I5I, I52 are arranged for sliding motion in a direction transverse to the face of the control member I43 so that when either one or the other of the pins I5I, I52 projects beyond the face of the control member I43, it is engaged by the periphery of the rotating cam I46 and pushed thereby to bring the control member I43 to one of its end positions in which one or the other of the coupling members 226, I21 is selectively actuated to the raised position while the other is lowered. The two catch pins I5I, I52 may be arranged to be normally biased to an inward position in which their ends are out of the path of the rotating cam I46 and one or the other of the actuating pins I5I, I52 is arranged to be selectively pushed outwardly into engagement with the cam disc by selective actuation of an associated magnet coil I5II, I52-I.

The required control motion may be imparted to the control member I43 either by a separate small auxiliary motor I41-I or, if the driving motor is maintained continuously energized and the application of the driving force is controlled solely by the operation of a coupling member, such as the coupling members 226, I21, the main driving motor I20 may be directly utilized for supplying power through a suitable reduction gearing to an element, such as the cam I46 which is utilized for moving the control member to its different operating positions.

The two magnets I5II, I522 are shown controlled electrically through either one of the actuating switches I53, I54 of a circuit from a source indicated by and signs. The circuit to each magnet also includes interlocking switches I55, I56, respectively, which are biased to a closed position and are actuated to an open position by one of the two nose projections I51 provideo. in the two regions of the control member I43 so that when either one of the actuating switches I53, I54, for instance. switch I54, is closed, it will energize magnet I52-I to actuate pin I52 to the outward position, causing the cam to shift the control member to the right in which end position, the right-hand nose projection I51 will open the circuit to the magnet I52-I and restore its catch pin I52 to the retracted position.

The interlocking arrangement assures that the control member I43 always remains in one of the end positions and that the two actuating pins I5 I I52 remain in their retracted inoperative positions and that they are actuated to their operative positions only upon actuation of the associated operating switches I53, I54. Furthermore, the catch pins I5I, I52 are retracted to their inoperative position through the opening of their associated interlocking switch I55, irrespective of whether their respective actuating switches I53, I54 are closed or not.

The closure of either one or the other of the two switches I53, I54 results in automatic reversal of the connection between the driving force and one or the other of the reel shafts I 89, I

in their proper sequence so that the coupling con-l" I58, I59 indicated diagrammatically as leading to a central amplifier and control unit I60 which combines all the amplifier and control circuits associated with the device for controlling the recording, reproducing, rewinding and other operations, the control device being shown provided with a suitable number of actuating buttons I'I arranged so that pushing a button starts and brings about the automatic performance of the desired operation,

The elements of the cam surface regions of th control member I43 are made sufficiently long, and the range and the speed of the motion imparted to the control member I43 either manually or automatically, for instance, by the operation of the cam I45, is so chosen that when efiecting a reversal of the driving connections, for instance, from the conditions shown in Fig. 2 in which reel 49 is driven in clockwise dimetion, to the condition in which reel 56 is driven in counterclockwise direction, the driving connection of reel 49 to the source of its driving force, is first opened and a brake action is applied thereto so that reel 49 is positively stopped, for an instant before the further motion of the control member I43 to the opposite position opens the braking connection of reel 50 and establishes its driving connection to the source of its driving force, represented by gear I25.

In order to make it possible to drive the reels with a relatively small motor, the drive-brakeforce applying members 226, I21 may be arranged for electrical actuation only, as by magnets indicated at I39, so that whenever a driving force is applied to a reel, the braking action applied thereto is automatically removed, and that removal of the driving force automatically restores the braking action applied to the respectivereels,

and that in reversing the drive connections, the series of operations involved in stopping the reels before applying the reverse driving forces is automatically performed in the proper timed sequence, as by an arrangement of time-action relays operating in an automatically interlocked timing sequence.

As indicated in Fig. 2, the interlocking switches I62, I63, through which the selective application of the braking and driving forces is determined, may be controlled by the operation of the control member I43 which, as shown, has two additional nose projections I64, I55 which selectively close the circuit to the driving motor I20 only when the control magnet I39 of the associated coupling member 226, I21 is actuated to remove the braking action and to permit the application of the motor driving force to the associated reel 49, 50, respectively, as well as to assure the required time sequence of operations involved in reversing the drive connections as explained above, with or without the combined use of the control member I43 itself for directly performing the driveand brake-coupling or uncoupling operations.

Means are also provided for automatically interlocking the operation of the elements of the motor unit 4| with the operation of the elements forming part of the reel holder unit 40 as by means of a pair of multi-pole electric connector members I1 I, I12, such as plug and socket members of the type used for interconnecting amplifier circuit devices, mounted in outwardly exposed positions on the mounting wall 42 of the guide unit 40 and on the coupling wall 80 of the motor unit 4|. The terminal elements of the coupling member I1I are shown connected through leads to the magnetic head, and the terminal elements of the coupling member I12 are shown connected through a cable I13 to the amplifier and control unit I60, only portions of the cable I13 being shown for the sake of simplicity. The connector elements I1I, I12 as well as all other coupling elements, mechanical or electrical, which serve to interconnect operating parts of the reel holder 40 and the motor unit 4|, are of the self-centering type and are designed to embody suificient self-restoring yieldability, as to assure that when the reel-holder guide unit 40 is coupled to the motor unit M in its automatically aligned position determined by the register pins 8|, all the coupling connections are properly established.

Fig. 2 also shows automatic interlocking means for stopping the driving mechanism when a predetermined part, for instance, all but the anchoring end, of the signal carrier has been transported from one reel to the other. The traveling indicator nut IOI is designed to engage and push to one or the other side the stop blocks I14, for instance, adjustably affixed to guide rod I03 so as to actuate the guide rod I03 to the right or the left and cause its end portions I03-I thereof to open one or the other of two interlocking switches I15 mounted in the motor unit M and having portions projecting, for instance, into the path of motion of the ends I03--I of the guide rod I03.

The interlocking switches I15 are utilized to perform an operation which results in automatically stopping the motion of the reels whenever one of the two switches I15 is actuated from its non-actuated position shown. These switches may be utilized either to control the operation of the driving motor I20 or of any other elements associated with the transmission of the driving forces and the application of the braking forces to the two reels.

: 'In the arrangement shown, the interlocking switches I15 are connected in the circuit through which the motor I20 is energized, the motor circuit being completed through its interconnection by way of either lead I16 througha suitable control device of the amplifier unit to a power supply terminal I11, or through a similar connection of the other lead I18 to a similar power supply lead I11.

There are also provided means for automatically interlocking the operation of the driving mechanism with the parts which control the timing of the coupling and braking actions. As shown in Fig. 2, an additional switch element I82, I83 may be combined with two switch elements I62, I63 so as to be automatically actuated therewith by the nose projections I64, I65, respectively, of the control member I4I, when the latter reaches or leaves one of its end positions, respectively, the additional switches I82, I83 are shown interconnected in the two energizing circuits I10, I18, respectively, of the driving motor I20.

This interlocking arrangement assures that the electrical motor drive and control connections can be established only in the end position of the mechanical time-action control element I43, after all mechanical coupling and uncoupling operations have been performed in their proper timed sequence, and that even in case the electric power, required for energizing the driving motor I20 and the various electric control circuits, fails, the reels will remain in their arrested position and the signal carrier wire'45 will be kept under tension.

As used herein in the specification and claims the expression magnetic record transducing is intended to mean either the operation of magnetically recording signals on a magnetic recording medium, or the operation of reproducing magnetically recorded signals, or the operation of erasing magnetically recorded signals, or any combination of two or more of these operations.

It will be apparent to those skilled in the art that the novel principles of the invention disclosed herein in connection with specific exemplifications thereof will suggest various other modifications and applications of the same. It is accordingly desired that in construing the breadth of the appended claims they shall not be limited to the specific exemplifications of the invention described above.

I claim:

1. In a magnetic record transducing apparatus for transducing magnetic records, such as recording or reproducing magnetic signals: a long magnetic record track; magnetic signal transducing means including windings for transducing records by varying magnetic flux interlinking said windings and a moving element of said track; guiding means for guiding and impelling said track past said transducing means including two rotatably mounted reels storing the major part of said track in coiled form so that a driving force imparted to one reel for winding thereon said track will cause the track to rotate the other of said reels while the track is being withdrawn therefrom; drive means actuable to apply driving forces to one of said reels for winding thereon the record track and braking means for applying braking forces tending to stop the rotation of said reels; and control means for selectively controlling the application of said driving forces of said driving means to either one of said reels;

to apply the driving forces to the other reel said control means first removes said driving forces from said one reel and cause said one reel to be substantially stopped by the action of said braking forces, and that after a time delay determined b said time action means said control means cause said driving forces to be applied to said other reel after said one reel has been first substantially stopped. i

2. In a magnetic record transducing apparatus for transducing magnetic records, suchas recording or reproducing magnetic signals: a long magnetic record track; magnetic signal transducing means including windings for transducing records by varying magnetic fiux interlinking said windings and a moving element of said track: guiding means for guiding and impelling said track past said transducing means including two rotatably mounted reels storing the major part of said track in'spirally-coiled form so that a driving force imparted to one reel for winding thereon said track will cause the track to rotate the other of said reels while the track is being withdrawn therefrom; drive means actuable to ap ly driving forces to one of said reels for winding thereon the record track and braking means for a plying braking forces tending to stop the rotation of said reels: said drive means including electrically energized motor means and couplin means actuable to establish or remove a driving connection from said motor means to e ther of said reels; and control means for selectively COIltlOllillg the application of said driving forces of said driving means to either one of said reels: said control means including time-action means and being so designed that when actuated to remove the driving forces from one reel and to apply the driving forces to the other reel said control means operate in a predetermined sequence under the control of said time-action means to first de-energize said motor means and cause said reels to be substantially stopped by the action of said braking means. then remove the driving connection from said one reel, and thereafter apply the driving forces to said other reel after said one reel has been first substantiallv stopped.

3. In a magnetic record transducing apparatus for transducing magnetic records. such as recording or reproducing magnetic signals: a long magnetic record track; magnetic signal transducing means including windings for transducing records by varying magnetic flux interlinking said windings and a moving element of said track: guiding means for guiding and impelling said track past said transducing means including two rotatabl mounted reels storing the major part of said track in coiled form so that a driving force imparted to one reel for winding thereon said track will cause the track to rotate the other of said reels while the track is being withdrawn therefrom; drive means actuable to apply driving forces to one of said reels for winding thereon the record track and braking means for applying brakin forces tending to stop the rotation of said reels; and control means for selectively controlling the application of said driving forces of said driving means to either one of said reels; said control means including preventive means and being so designed that when actuated to remove the driving forces from one reel and to apply the driving forces to the other reel said control means operate in a predetermined sequence under the control of said preventive means to first remove the driving forces from said one reel and cause said reels to be substantially stopped by the action of said braking means, and after a predetermined time delay to apply the driving forces to said other reel after said first reel has been first substantially stopped.

4. In a magnetic record transducing apparatus for transducing magnetic records, such as recording or reproducing magnetic signals: a long magnetic record track; magnetic signal transducing means including windings for transducing records by varying magnetic flux interlinklng said windings and a moving element of said track; guiding means for guiding and impelling said track past said transducing means including two rotatably mounted reels storing the major part of said track in coiled form so that a driving force imparted to one reel for winding thereon said track will cause the track to rotate the other of said reels; drive means actuable to apply driving forces to one of said reels for winding thereon the record track andbraking means for applying braking forces tending to stop the rotation of said reels: said drive means including electrically energized motor means and coupling means actuable to establish or remove a driving connection from said motor means to either of said reels; and control means for selectively controlling the application of said driving forces of said driving means to either one of said reels; said control means including time-action means and being so designed that when actuated to remove the driving forces from one reel and to apply the driving forces to the other reel said control means operate in a predetermined sequence under the control of said time-action means to first deenergize said motor means to cause said reels to be substantially stopped by the action of said braking means, then uncouple said motor means from said one reel, and after a predetermined time delay apply the driving forces to'said other reel after said first reel has been first substantially stopped.

5. In a magnetic record transducing apparatus for transducing magnetic records, such as recording or reproducing magnetic signals: a long magnetic record track; magnetic signal transducin means including windings for transducing records by varying magnetic flux interlinking said windings and a moving element of said track; guiding means for guiding and impelling said track past said transducing means including two rotatably mounted reels storing the major part of said track in coiled form so that a driving force imparted to one reel for windin thereon said track will cause the track to rotate the other of said reels; drive means actuable to apply driving forces to one of said reels for winding thereon the record track and braking means for applying braking forces tending to stop the rotation of said reels; said drive means including electrically energized motor means and coupling means actuable to establish or remove a driving connection from said motor means to either of said reels; and control means for selectively controlling the application of said driving forces of said driving means to either one of said reels; said control means including time-action means and being so designed that when actuated to remove the driving forces from one reel and to apply the driving forces to the other reel said control means operate in a predetermined sequence under the control of said time-action means to first de-'- energize said motor means to cause said reels to be substantially stopped by the action of said for transducing magnetic records, such as recording or reproducing magnetic signals: a long magnetic record track: magnetic signal transducing means including windings for transducing records by varying magnetic fiux interlinking said windings and a moving element of said track;

' guiding means for guiding and impelling said track past said transducing means including two rotatably mounted reels storing the major part of said track in spirally-coiled form so that a driving force imparted to one reel for winding thereon said track will cause the track to rotate the other of said reels; drive means including electric motor means actuable to selectively apply driving forces to one of said reels for winding thereon the record track and braking means for applying braking forces tending to stop the rotation of said reels: and control means for selectively controlling the application of said driving forces of said driving means to either one of said reels: said control means includin timeaction means and being so desi ned that when it is actuated to remove the driving forces from one reel and apply the driving forces to the other reel said control means first de-energize said motor means and remove said driving forces from said one reel and cause said one reel to be substantially stopped by the action of said braking forces and that after a time delay determined by said time action means said control means cause said driving forces to be applied to said other reel and energizes said motor after said one reel has been first substantially stopped.

'7. In a magnetic record transducing apparatus for transducing magnetic records. such as recording or reproducing magnetic signals: a long magnetic record track; magnetic signal transducing means including windings for transducing records by varying magnetic flux interlinking said windings and a moving element of said track; guiding means for guiding and impelling said track past said transducing means including two rotatably mounted reels storing the major part of said track in spirally-coiled form so that a driving force imparted to one reel for winding thereon said track will cause the track to rotate the other of said reels; drive means including electric motor means and coupling means actuable to selectively couple said motor means to one of said reels for winding thereon the record track and braking means for applying braking forces tending to stop the rotation of said reels; and control means for selectively controlling the application of said driving forces of said driving means to either one of said reels; said control means including time-action means and being so. designed that'when it is actuated to remove the driving forces from one reel and apply the driving forces to the other reel said control means auas'n 8. In a magnetic record transducing apparatus for transducing magnetic records, such as recording or reproducing magnetic signals: a long magnetic record track; magnetic signal transducing means including windings fortransducing records by varying magnetic flux interlinking said windings and, a moving element of said track guiding means for guiding and impelling said track past said transducing means including two rotatably mounted reels storing the major part of said track in spirally-coiled form so that a driving force imparted to one reel for winding thereon said track will cause the track to rotate the other of said reels; drive ,means actuable to apply driving forces to one of said reels for winding thereon the record track and braking means for applying braking forces to the reel from which the record track is unreeled; and control means for selectively controlling the application of said driving forces of said driving means to either one of said reels; said control means being so designed that when it is actuated to remove the driving forces from one reel and apply the driving forces to the other reel said control means first removes said driving forces from said one reel and causes said one reel to be substantially stopped by the action of said braking forces exerted on the other reel and that after a time delay determined by said time action means causes said driving forces to be applied to said other reel after said one reel has been first substantially stopped.

9. In a magnetic record transducing apparatus for transducing magnetic records, such as recording or reproducing magnetic signals; a long magnetic record track; magnetic signal transducing means including windings for transducing rectrack past said transducing means including two first de-energize said motor means and uncouple rotatably mounted reels storing the major part of said track in spirally-coiled form so that a driving force imparted to one reel for winding thereon said track will cause the track to rotate the other of said reels; drive means actuable to apply driving forces to one of said reels for winding thereon the record track and braking means for applying braking forces tending to stop the rotation of said reels; said drive means including electrically energized motor means and coupling means actuable to establish or remove a driving connection from said motor means to either of said reels; and control means for selectively controlling the application of said driving forces of said driving means to either one of said reels: said control means including time action means and being so designed that when actuated to remove the driving forces from one reel and apply the driving forces to the other reel said con trol means operates in a predetermined sequence under the control of said time action means to first de-energize said motor means and cause said reels to be substantially stopped by the action of said braking means, exerted on the other reel: thereafter remove the driving connection from said one reel, and thereafter apply the driving forces to said other reel after the first reel has been first substantially stopped.

10. In a magnetic record transducing apparatus for transducing magnetic records, such as recording or reproducing magnetic signals a long magnetic record track; magnetic signal transducing means including windings for transducing records by varying magnetic flux interlinking said windings and a moving element of said track; guiding means for guiding and impelling said track past said transducing means including two rotatably mounted reels storing the major part of said track in spirally-coiled form so that a driving force imparted to one reel for winding thereon said track will cause the track to rotate the other of said reels: drive means actuable to apply driving forces to one of said reels for winding thereon the record track and braking means for applying braking forces tending to stop the rotation of said reels; said drive means including electrically energized motor means and coupling means actuable to establish or remove a driving connection from said motor means to either of said reels and control means for selectively controlling the application of said driving forces of said driving means to either one of said reels; said control means including time action means and being so designed that when actuated to remove the driving forces from one reel and apply the driving forces to the other reel said control means operates in a predetermined sequence under' the control of said time action means to first de-energize said motor means and cause said reels to be substantially stopped by the action of said braking means, exerted on the other reel: thereafter uncouple the motor means from said one reel. then couple the motor means to said other reel. and thereafter energize said motor means so that the driving forces are applied to said other reel after said first reel has been first substantially stopped.

11. In a magnetic recording apparatus: a long magnetic record track: magnetic signal transducing means for recording and reproducing signals by magnetic flux variations interlinking said transducing means and an element of said track moving past it; guiding means for guiding and impelling said track past said transducing means including two revolvably mounted reels for storing the major part of said track in spirallycoiled form so that a driving force imparted to one reel for rotating it and winding thereon said track will cause the track to rotationally drive the other of said reels while being withdrawn therefrom; drive means actuable to selectively apply driving forces to one of said reels for rotating the same and brake means for applying braking forces to said one reel for stopping rotation of said reels; and control means for controlling the operation of said drive means and said brake means operative to remove the braking forces from said one reel when the driving forces are applied thereto and to apply braking forces when the driving forces are removed therefrom; said control means being arranged to prevent the application of the driving forces to one reel when driving forces are applied to the other reel; said control means including time action means and being so designed that upon actuation thereof to remove the driving forces from one reel and apply driving forces to the other reel said control means operate in a predetermined sequence under the control of said time action means to first remove the driving forces from said one reel and cause said one reel to be substantially stopped by the action of said braking forces before the driving forces are applied to the other reel.

12. A magnetic recording apparatus as defined in claim 11, in which the control means include interlocking means operative upon actuation of the control means to remove the driving forces from one reel and apply driving forces to the other reel to first cause the application of braking forces to said one reel and prevent the application of driving forces to said other reel before said one reel is stopped. Y

13. A magnetic recording apparatus as defined by claim 11, in which the control means include interlocking means having a movable time-action member operative upon actuation of the control means to remove the driving forces from one reel and apply driving forces to the other reel to first cause the application of braking forces to said one reel and prevent the application of the driving forces to said other reel before said one reel is stopped. V

14. A magnetic recording apparatus as defined by claim 11, in which the control means including interlocking means operative upon actuation of the control means to remove the driving forces from one reel and apply driving forces to the other reel to first cause the application of braking forces to said one reel and prevent the application of driving forces to said other reel before said one reel is stopped.

SEMI JOSEPH BEGUN.

REFERENCES CITED The following references are of record in the file of this patent:

' UNITED STATES PATENTS Number Name Date 789,336 Poulsen et a1. May 9, 1905 2,369,017 Camras Feb. 6, 1945 2.335277 Heller i. Nov. 30, 1943 2,213,631 Heller Sept. 3, 1940 2,089,287 Molloy Aug. 10, 1937 2,086,130 Hickman July 6, 1937 2,078,357 Woodmansee Apr. 27, 1937 1,123,147 Sherman Dec. 29, 1914 1,886,856 Warwick Nov. 8, 1932 1,665,784 Nornauer Apr. 10, 1928

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