US3730017A - Control mechanism - Google Patents

Abstract

A control mechanism for an electrical apparatus includes a frame member, a handle pivotably mounted on the frame member and adapted to be manually grasped for operating the control mechanism. The control mechanism includes first and second electrical control means. The first electrical control means is operably associated with the control handle and adaptable to provide one polarity of output signal in response to movement of the control handle in one direction from an initial neutral position and the opposite polarity of output signal in response to movement of said control handle in the opposite direction from the neutral position. The control mechanism further includes a linkage means connected between the control handle and the second electrical control means whereby the second electrical control means will be operated in the same direction and to the same extent for a given amount of movement of the control handle in either direction from the neutral position thereby enabling the second electrical control means to be adapted to regulate the magnitude of output signal of the control mechanism irrespective of the direction of control handle movement.

Description

United States Patent [1 1 Primary Examiner-Milton Kaufman Attorney-Leslie H. Blair et al.

Liddell May 1, 1973 CONTROL MECHANISM [57] ABSTRACT [75] Inventor: Arlyn G. Liddell, Bountiful, Utah A control mechanism for an electrical apparatus includes a frame member, a handle pivotably mounted [73] Assignee. Eaton Corporation, Cleveland, Ohio on the frame member and adapted to be manually [22] Filed: Aug. 20, 1971 grasped for operating the control mechanism. The

[2 U Appl No: 173,440 control mechanism includes first and second electrical control means. The first electrical control means is operably associated with the control handle and [52] US. Cl. ..74/47l R, 74/98, 200/153 T, adaptable to provide one polarity f output Signal in 338/172 response to movement of the control handle in one [51] Iltl. Cl. ..G05g 9/00 direction from an initial neutral position and the Field of Search XY, R, posite p y of output g l i response to move 74/98; 200/6 6 153 T; 318/295; ment of said control handle in the opposite direction 338/7820O 172 from the neutral position. The control mechanism further includes a linkage means connected between [56] References Cited the control handle and the second electrical control UNITED STATES EN S means whereby the second electrical control means will be operated in the same direction and to the same :2 gg'gj extent for a given amount of movement of the control handle in either direction from the neutral position thereby enabling the second electrical control means to be adapted to regulate the magnitude of output signal of the control mechanism irrespective of the direction of control handle movement.

7 Claims, 7 Drawing Figures CONTROL MECHANISM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to electrical control mechanisms of the type used in controlling both the speed and direction of rotation of electrical motors. More specifically, the present invention relates to a control mechanism for electric motors wherein an operator manually regulates the speed and direction of such motors by movement of a control handle in the displacement of the control handle from the neutral position to provide for incremental steps in the rotational speed of a motor which may be connected in a circuit with the control mechanism.

2. Description of the Prior Art Control mechanisms for controlling both the speed and direction of motors are generally known in the art. Furthermore, control mechanisms that control both the speed and direction of rotation of motors which utilize a single control handle to control both speed and direction of rotation are also known in the art. An example of such a device is US. Pat. No. 3,550,466 issued Dec. 29, 1970 to .I. E. Ham. One of the problems of the prior art devices when applied to machines requiring precise control is a human engineering problem in that movement of the control handle to the same extent but in different directions from the neutral position results in different speeds of rotation of the motor. Consequently, it is extremely difficult with prior art devices for an operator to become accustomed to the control whereby he can accurately control the speed of rotation of the motor. This is mainly due to the fact that movement of the control handle by the operator in different directions but to the same extent from the neutral position, results in a different magnitude of electrical signal being applied to the motor depending on the direction in which the operator moves the control handle.

Another problem of prior art devices is that a separate electrical speed control mechanism is required for each direction of movement. Moreover, the addition of a separate speed control further aggravates the aforementioned human engineering problem, especially if the separate speed control mechanisms are not precisely calibrated or matched thus adding extra expense and complexity to the control mechanism over and above that added by the extra speed control alone. Here, it should be noted that in the aforementioned Ham patent, a separate portion of the potentiometer internal circuit is used for movement in one direction as opposed to movement in the opposite direction.

SUMMARY OF THE INVENTION The present invention overcomes the foregoing disadvantages by providing a control handle pivotably mounted on a frame for movement from an initial neutral position to a plurality of actuated positions. Associated with the control handle and adapted to be selectively actuated by movement thereof to anyone of the plurality of actuated positions is a first electrical control apparatus comprising a series of electrical switches. One switch is preferably used for each direction in which the control handle can be manipulated, thereby allowing the polarity of the output signal to be determined by the direction of movement of the control handle from the initial position.

Also, associated with the control handle and adapted to be actuated by movement thereof is a second electrical control apparatus. The second electrical control apparatus is of the type capable of regulating the magnitude of the output signal irrespective of the polarity. The second electrical control apparatus is positioned and associated with the control handle through linkage means which insure that the second electrical control mechanism is actuated in the same direction and to the same magnitude for given amounts of displacement of the control member in either direction from the initial position. This is accomplished by providing that the second electrical control mechanism is always at zero displacement when the control member is in the neutral position and is always moved in the same direction towards maximum displacement irrespective of the direction of movement of the control member. In a preferred embodiment, this is accomplished by a rack and pinion linkage.

Accordingly, it is an object of this invention to provide a joy stick type of control mechanism which is adaptable for controlling both the speed and direction of rotation of an electric motor and wherein the same speed control apparatus is used for controlling the speed of rotation in both directions.

Another object of the present invention is to provide a new and novel control mechanism for electric motors wherein a control mechanism is operable to regulate both the speed and direction of rotation of the electric motors and wherein the magnitude of the speed of rotation of the electric motors is regulated by means which are operated in the same direction and to the same extent for a given displacement of a control handle of said control mechanism from an initial neutral position.

Another object of the present invention is to provide an electrical control mechanism having linkage means and wherein the control mechanism includes a member movable in a plurality of directions from an initial neutral position, means for regulating the polarity of an output signal of said control mechanism by the direction of movement of said member from said initial position and means for regulating the magnitude of said output signal by the magnitude of displacement of said member from said initial position wherein said means for regulating the magnitude of said output signal is operated in the same direction for movement of said member in either direction from said initial position by said linkage means.

Other objects and advantages of the present invention will become more apparent from the description of the preferred embodiment which follows hereinafter.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an isometric view of the preferred embodiment of the invention of the instant application;

FIG. 2 is a left side elevational view of the preferred embodiment of the instant application;

FIG. 3 is a front elevational view of the preferred embodiment of the instant application;

FIG. 4 is a right side elevational view of the preferred embodiment of the control mechanism of the instant application;

FIG. 5 is a right side elevational view of an alternate embodiment of the invention of the instant application,

FIG. 6 shows a schematic wiring diagram for the direction control;

FIG. 7 shows a schematic wiring diagram for the speed control.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1 and 2 wherein there is shown a Control mechanism 10 having a frame portion 12 with a control member or handle 14 pivotably mounted thereon by means of a shaft or pin 16 passing therethrough. Located intermediate the frame member 12 and the handle 14 is a hair pin spring member 18 configured to engage a pair of stop members 20, 22 on the'control handle and frame respectively, thereby insuring that the control handle 14 is biased toward the neutral or upright position. Limit stops 24 and 26 are provided on the frame member to control the maximum extent of movement of the control handle 14.

Pivotably attached to the lower end of the control handle 14 by means of screw 28 is linkage means 30 including rack 32 integrally attached thereto.

Positioned in driving engagement with rack 32 is a pinion 34 which is also drivingly mounted on a shaft 36 extending through the frame member 12. Maintaining engagement between the rack 32 and the pinion 34 by means of shaft 36 pivotably passing therethrough is a sheet metal guide member 38. It should be noted that the sheet metal guide member 38 permits free relative sliding movement of rack 32 and free relative rotational movement of pinion 34 while maintaining driving engagement between these two members. This is accomplished by allowing the shaft 36 which passes therethrough to have free rotational movement with respect to guide member 38.

At this point, it should be noted that the pivotal connection 28 between the control handle 14 and rack 32 is positioned intermediate the pivotal connection 16 and the pinion shaft 36 thereby insuring that the rack 32 always moves in an upward direction for movement of control handle 14 in either direction from the neutral position.

Referring now to FIG. 4 wherein there is shown a cam member 40 disposed atthe end of shaft l6 opposite handle 14 and in driving engagement therewith. The cam member 40 has lobes 40a and 40b extending from base circle 40c. Mounted on frame member 12, disposed adjacent the cam member 40 and adapted to be actuated thereby upon movement thereof are a pair of normally opened micro switches 42 and 44. It should be apparent at this point that movement of the control member 14 to the right in FIG. 4 will cause cam lobe 40a to close micro switch 42 while leaving micro switch 44 in the normally opened position resting on base cir-.

cle 40c and vice versa, movement of the control member 14 to the leftward direction will rotate cam 40 in the counterclockwise direction thereby causing lobe 40b to close micro switch 44 while leaving micro switch 42 in the normally opened position.

The micro switches 42,44 have terminals 46 and 48 respectively. Accordingly, it should now be evident to one of ordinary skill in the art that the micro switches 42, 44 may be advantageously connected into an electrical circuit (not shown) associated with the control mechanism of the instant invention and thereby be enabled to reverse the direction of current flow of polarity in said electrical circuit upon selective actuation thereof by movement of the control handle 14 in either the rightward or leftward direction as shown in FIG. 4. Since electrical circuits for reversible motors which control both the speed and direction of rotation thereof are well known in the art, the circuit will not be described in detail. 7

Further, as shown in FIG. 4, disposed at the end of shaft 36 opposite pinion 34 and adapted to be regulated by rotation thereof is a single potentiometer or rheostat 50 having electrical terminals 52, 53, 54 for connection to the aforementioned electrical circuit. Rotation of the pinion 34 in one direction will increase the potentiometer setting and rotation of the pinion in the opposite direction will decrease the potentiometer setting with the setting approaching a zero signal condition when the control handle is in the upright or neutral position.

With reference to FIG. 5, there is shown an alternate embodiment wherein the potentiometer or rheostat S0 of the preferred embodiment has been replaced by a second cam 60 and a second pair of normally open micro switches 62, 64 respectively adapted to be actuated thereby upon movement thereof.

The cam 60 is drivingly mounted on the end of pinion shaft 36 and is thereby adapted to be rotated in the same manner as previously described with respect to the potentiometer shaft of the preferred embodiment. 1 t i It should be noted that the polarity of output signal is controlled by the same mechanism previously described with respectto the preferred embodiment.

The cam 60 (FIG. 5) includes a detent 66 positioned to receive a roller 68 disposed on an actuating arm 70 of micro switch 62 thereby allowing micro switch to be in its normally open position when the control handle 14 is in the neutral or upright position and to be closed by rotation of the cam member in a counterclockwise direction when the control handle is moved in either direction. The cam 60 further includes a lobe 72 positioned to engage a roller 74 on an actuating arm of micro switch 64, thereby enabling micro switch 64 to be closed upon a predetermined degree of rotation of the cam 60. Upon initial rotation of cam 60 the first micro switch 62 will be closed thereby allowing an output signal of a first magnitude to be applied to a control circuit for an electric motor (not shown). Upon further rotation of cam member 60, the second micro switch 64will be closed by engagement with lobe 72, thereby allowing an additional magnitude of electrical signal to be applied to the control circuit. Thus in this alternate embodiment, the control mechanism of the instant in vention is thereby enabled to provide a plurality of finite steps in the electrical output signal. It should be noted that additional switches and cam lobes can be added to provide any desired number of finite steps. The important feature is that the cam 60 rotates in the same direction irrespective of the direction of movement of the control handle 14 from the initial or neutral position, thereby Causing each finite step to occur at exactly the same degree of displacement of the control handle irrespective of the direction of movement thereof.

DESCRIPTION OF OPERATION Movement of the control handle 14 in either direction from the initial position against the biasing force of hairpin spring 18, will rotate shaft 16 thereby causing cam 40 to selectively actuate one of the micro switches 42, 44 by closing it while allowing the other switch to remain open. Activation of one of these switches will determine the polarity of the electrical circuit and consequently the direction of rotation of a motor connected in circuit (not shown) which the control mechanism regulates. Further, movement of the control member 14 will cause an upward movement of rack 32 and consequently clockwise rotation of pinion shaft 36. This is true for movement of the control member 14 in either direction from the neutral or upright position because pivot connection 28 is intermediate pivot 16 and pinion shaft 36. This movement increases the setting of potentiometer or rheostat 50 to apply a magnitude of potential across output terminals 52, 53, 54 which is proportional to the extent of movement of control handle 14. Conversely, movement of the control handle 14 from any actuated position toward the neutral position will cause a corresponding counterclockwise rotation of pinion shaft 36 (FIG. 4) and consequent decrease in the magnitude of electrical potential applied across output terminals 52, 53, 54. The magnitude of potential applied is completely independent of the direction of movement of control member 14 and is only dependent upon the magnitude of movement of control member 14 from the neutral position.

Having described my invention so as to enable one of ordinary skill in the art to practice it,

I now claim:

1. An electrical control mechanism comprising:

a frame member,

a control handle pivotally mounted on said frame member for movement between a neutral position and a plurality of actuated positions,

first electrical control means associated with said control handle and adaptable to polarize an electrical circuit to one polarity upon movement of said control handle toward one of said actuated positions from said neutral position and adaptable to polarize said electrical circuit to the opposite polarity upon movement of said control handle toward another of said actuated positions from said neutral position,

second electrical control means adapted to regulate the amount of electrical current flowing through said electrical circuit upon actuation thereof,

and linkage means connected between said control handle and said second electrical control means for unidirectionally rotating a control member of said second electrical control means in proportional response to a displacement of said control handle in either direction from said neutral position.

2. An electrical control mechanism comprising:

a frame member,

a control handle pivotally mounted on said frame member for movement between a neutral position and a plurality of actuated positions,

first electrical control means associated with said control handle, said first electrical control means having terminals which are polarized in one direction upon movement of said control handle toward one of said actuated positions from said neutral position and polarized in the reverse direction upon movement of said control handle toward another of said actuated positions from said neutral position,

second electrical control means aetuatable to regulate the amount of electrical potential across said terminals upon actuation thereof,

and a rack and pinion assembly connected between said control handle and said second electrical control means for actuating said second electrical control means to regulate the potential across said terminals in unidirectional response to the displacement of said control handle from said neutral position toward any of said actuated positions.

3. A control mechanism comprising:

a frame member,

a control handle pivotally mounted on said frame member for movement between a neutral position and a plurality of actuated positions,

a first cam positioned to be rotated by movement of said control handle,

first electrical control means comprising a pair of normally open electrical switches positioned adjacent said first cam to be selectively actuated thereby upon rotation thereof, one of said switches being actuated by movement of said control handle toward one direction from the neutral position and the other being actuated by movement of said control handle in the opposite direction from the neutral position,

second electrical control means mounted on said frame member, and

linkage means connecting said second electrical control means to said control handle, said linkage means being effective to unidirectionally move said second electrical control means an amount proportional to a given movement of said control handle in either direction from said initial position.

4. The invention as defined in claim 3 wherein said linkage means comprises a pinion mounted on a shaft of said second electrical control means for rotative movement relative to said frame member, I

and a rack disposed in driving engagement with said pinion and pivotably attached to said control handle and wherein the pivotal attachment between said control handle and said rack is intermediate said pinion and the pivotal attachment of said control handle to said frame whereby said rack always moves in the same direction for increasing displacement of said control handle from said initial position.

5. The invention of claim 4 wherein said second electrical control means comprises a potentiometer and ated by rotation of said second cam.

7. The invention as defined by claim 4 including a guide member slidably embracing said rack and wherein the shaft of said second electrical control means rotatably passes through said guide member whereby said guide member is effective to maintain driving engagement between said rack and said pinion.

Claims (7)

1. An electrical control mechanism comprising: a frame member, a control handle pivotally mounted on said frame member for movement between a neutral position and a plurality of actuated positions, first electrical control means associated with said control handle and adaptable to polarize an electrical circuit to one polarity upon movement of said control handle toward one of said actuated positions from said neutral position and adaptable to polarize said electrical circuit to the opposite polarity upon movement of said control handle toward another of said actuated positions from said neutral position, second electrical control means adapted to regulate the amount of electrical current flowing through said electrical circuit upon actuation thereof, and linkage means connected between said control handle and said second electrical control means for unidirectionally rotating a control member of said second electrical control means in proportional response to a displacement of said control handle in either direction from said neutral position.

2. An electrical control mechanism comprising: a frame member, a control handle pivotally mounted on said frame member for movement between a neutral position and a plurality of actuated positions, first electrical control means associated with said control handle, said first electrical control means having terminals which are polarized in one direction upon movement of said control handle toward one of said actuated positions from said neutral position and polarized in the reverse direction upon movement of said control handle toward another of said actuated positions from said neutral position, second electrical control means actuatable to regulate the amount of electrical potential across said terminals upon actuation thereof, and a rack and pinion assembly connected between said control handle and said second electrical control means for actuating said second electrical control means to regulate the potential across said terminals in unidirectional response to the displacement of said control handle from said neutral position toward any of said actuated positions.

3. A control mechanism comprising: a frame member, a control handle pivotally mounted on said frame member for movement between a neutral position and a plurality of actuated positions, a first cam positioned to be rotated by movement of said control handle, first electrical control means comprising a pair of normally open electrical switches positioned adjacent said first cam to be selectively actuated thereby upon rotation thereof, one of said switches being actuated by movement of said control handle toward one direction from the neutral position and the other being actuated by movement of said control handle in the opposite direction from the neutral position, second electrical control means mounted on said frame member, and linkage means connecting said second electrical control means to said control handle, said linkage means being effective to unidirectionally move said second electrical control means an amount proportional to a given movement of said control handle in either direction from said initial position.

4. The invention as defined in claIm 3 wherein said linkage means comprises a pinion mounted on a shaft of said second electrical control means for rotative movement relative to said frame member, and a rack disposed in driving engagement with said pinion and pivotably attached to said control handle and wherein the pivotal attachment between said control handle and said rack is intermediate said pinion and the pivotal attachment of said control handle to said frame whereby said rack always moves in the same direction for increasing displacement of said control handle from said initial position.

5. The invention of claim 4 wherein said second electrical control means comprises a potentiometer and wherein the shaft of said potentiometer is rotated upon rotation of said pinion to regulate the setting of said potentiometer.

6. The invention as defined in claim 4 wherein said second electrical control means comprises a second cam disposed for rotation with said pinion and a plurality of normally open electrical switches mounted on said frame member and positioned to be serially actuated by rotation of said second cam.

7. The invention as defined by claim 4 including a guide member slidably embracing said rack and wherein the shaft of said second electrical control means rotatably passes through said guide member whereby said guide member is effective to maintain driving engagement between said rack and said pinion.

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