US2756058A - Transducer supporting and positioning means - Google Patents

Description

July 24, 1956 c. F. JENSEN TRANSDUCER SUPPORTING AND POSITIONING MEANS Filed Jan. 14, 1950 MWWWNNW. HHHW '7 INVENTOR. aarerzcellfensem W he: Mm? -51 NwN MN QN MN wwmw Wm Q Q Q Q,

m ww mm W) Qw United States Patent O TRANSDUCER SUPPORTING AND POSITIONING NIEANS Clarence F. Jensen, Racine, Wis., assignor to Webster Electric Company, Racine, Wis., a corporation of Delaware Application January 14, 1950, Serial No. 138,553

2 Claims. (Cl. 274-36) The present invention relates to transducer supporting and positioning means and has for one of its primary object of the present invention to provide new and improved apparatus facilitating construction of transducer apparatus and the selection of the needle for the playing of the different types of records.

Another object of the present invention is the provision of a new and improved pickup cartridge and support therefor characterized in that they form a separate structural assembly of which the cartridge is rotatably supported in the support for movement between two positions and the support is adapted readily to be secured in an associated tone arm. I I g i A further object of the present invention is the provision of a new and improved supporting and positioning structure for a multi-position pickup cartridge.

In the illustrative embodiment of the invention disclosed and described hereinafter, the pickup cartridge with its associated pair of needles is rotatably mounted upon a support so that it can be selectively operated to select one or the other of the needles. The cartridge and support constitute an assembly adapted readily to be mounted upon a tone arm. The cartridge is mounted in cantilever fashion upon the support and the latter, and the cartridge moving means, which also constitutes part of the assembly, are provided with cartridge positioning means, and with cartridge movement limiting means. Certain features of the invention, such as the cantilever support and positioning and movement limiting means are applicable to constructions in which the cartridge is supported upon the tone arm as distinguished from a special support.

Other objects and advantages of the present invention will become apparent from the ensuing description of an illustrative embodiment thereof in the course of which reference is had to the accompanying drawing, in which:

Fig. 1 is a fragmentary bottom plan view of a tone armpickup assembly embodying the invention and illustrating the cartridge conditioned for playing conventional records;

Fig. 2 is an enlarged side elevational view, partly in section, of the pickup cartridge-support assembly conditioned for playing micro-groove records;

Fig. 3 is a vertical cross-sectional view taken along the line 3-3 of Fig. 2; and

Fig. 4 is a fragmentary bottom plan view of a modification of the invention.

Referring now the drawing and first to Figs. 1, 2 and 3, the present invention is shown embodied in a tone armpickup combination a tone arm and a transducer 12 in the form of a pickup unit including a housing 14 from which there extend a plurality of styli or needles 16 and 18 for playing different types of records that may be placed on a turn table, not shown, but forming part of a record player unit, which may be of knownconstruction.

The cartridge 12 is movably mounted at the enlarged forward end of the tone arm and it is movable selectively .to bring a desired needle into position to engage a record placed on the turn table. In Fig. 1, the cartridge is shown positioned with needle 16 adapted to engage a record of the conventional type rotated at 78 R. P. M. At this time, the needle 13, which is designed for playing microgroove records, is positioned out of contact with the record. A convenient arrangement of the needles for playing two types of records is to have them at opposite sides of the cartridge, as shown, and to have the cartridge rotatable generally axially through an angle of for selection of the desired needle.

The cartridge may include a transducer element of known type connected by the terminals 20 and conductors 22 at its rear to associated apparatus.

The cartridge is supported and positioned in novel manner. In the first place the cartridge and its supporting structure are constructed as an assembly unit that can readily be secured in place on the tone arm. This assembly is shown in Fig. 2. The support, indicated as a whole by reference character 24, may be generally right angled or L-shaped with its longer arm 26 disposed above the cartridge and secured to the under side 28 of the top wall of the tone arm, and with its shorter arm 3% disposed vertieally in abutting relation to the front wall 32 of the tone arm. The support is secured to the tone arm as by screws 34 disposed and accessible at the sides of the cartridge 12, which, as may be noted from Fig. 1, is quite narrow.

The cartridge is rotatably supported in cantilever fashion in its support. This is accomplished by securing the cartridge to a shaft 36 rotatably journaled in a bearing element 38 secured, as by a press fit, in the shorter arm 30 of the support so as to extend outwardly through a relatively closely encircling downwardly opening slot 40 in the front wall 32 of the tone arm. It should be noted that the bearing element is of substantial length, thereby to provide what might be called a non-rocking support for the cartridge.

The cartridge is connected to the rearwardly projecting end of shaft 36 by a bracket 42, the main portion 44 of which is riveted, as by rivets 46, to the cartridge and having an apertured central transverse flange 48 to which the end of the shaft is fixedly secured. In order to prevent the conductors from being tangled and unduly twisted, the rotation of the cartridge is restricted to 180". This is done by forwardly projecting spaced lugs or ears 50 at the opposite edges of bracket 44 which are adapted to engage a rearwardly projecting finger 52, which may be stamped out from a part of the support, such as leg 30.

The cartridge is selectively movable into its two operative positions by a handle 54 secured to the forwardly projecting end of shaft 36, as by a set screw 56. The handle may be suitably marked for 33 /s--4S and 78 R. P. M. records.

The cartridge is positioned in its two operative positions by an arrangement comprising the diametrically oppositely located detent teeth 58, preferably formed at the outer end of bearing element and the cooperating slots 60 in the hub of the handle. The detent teeth are resiliently held in the slots by a spring 62 encircling shaft 36 and disposed between arm 39 of the support and flange 48 of the cartridge supporting bracket 42. The spring thus urges the cartridge and handle rearwardly, thereby to hold the movable portion of the assembly against undesired movement during operation and before assembly and also to hold the cartridge in its selected operative position.

Certain features of the invention are applicable also Patented July 24, v

to constructions in which the ed upon the tone arm, as illustrated in Fig. 4, to which reference is now had. Here the tone arm is provided with an enlarged boss 70 in its front wall. The cartridge 12 is mounted, as heretofore described, at the rear projecting end of shaft 36, which is journaled to the boss, the boss thus constituting a bearing element for the shaft. The handle 54 is secured to the forwardly projecting end of the shaft and it is provided with the diametrically oppositely located slots 60 which cooperate with the similarly located detent teeth 72, which can be intergal with boss 70.. The spring 62 thus serves to hold the cartridge and associated parts against undesired movement and in selected position. If desired some means corresponding to finger 52 may be provided to limit movement of the cartridge.

From the foregoing detailed description of the present invention, it may be noted that the cartridge is adapted simply to be mounted and movably supported upon a tone arm, for movement into selected positions for playing either conventional or microgroove records. The cartridge and the associated parts moved with it are not only held in selected position in a simple and inexpensive manner but are also held against undesired vibration in operation and, in case of the first described embodiment, prior to the time that the assembly is fastened in the tone arm. The assembly of the first embodiment also can be constructed inexpensively and easily and can be readily secured in position in a tone arm.

While the present invention has been described in connection with the details of particular embodiments thereof, it should be understood that these details are intended to be illustrative and not limitative of the-invention except as set forth in the accompanying claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a longitudinally extending tone arm having an apertured transverse end wall, a unitary transducer assembly for use with different types of records and adapted to be secured to said tone arm as a unit comprising a stationary structure including an L-shaped supporting member having a first plate-like leg adapted to be secured to the tone arm, a second plate-like leg having an aperture therein, and a hollow elongated cylindrical bearcartridge is movably mounte ing beyond both ends of said bearing, a transducer housing secured to the projecting end of said shaft adjacent said first leg, and means for rotating said shaft; said stationary and rotatable structures including housing positioning and rotation limiting means comprising first detent means on said stationary structure and second detent means movable withsaid shaft and located adjacent the first means for cooperation therewith to position and limit movement of said shaft and said housing in different operative positions; and resilient means connecting said shaft and said stationary structure to effect engagement of said first and second detent means in positions corresponding to different operative positions of the transducer relative to said different types of records.

2. In a longitudinally extending tone arm having an apertured transverse wall at the free end thereof, a unitary transducer assembly for use with different types of records and adapted to be secured to said tone arm comprising a stationary structure including a plate-like element having an aperture therein, and a hollow elongated cylindrical bearing structure mounted in the aperture of said element, means for securing said element to said tone arm with said cylindrical bearing structure extending through said apertured transverse wall; rotatable structure mounted on said stationary structure including a shaft journalled only in said bearing structure for rotary movement and extending beyond both ends of said bearing, a transducer housing secured to the projecting end of said shaft at one side of said element, and means for rotating said shaft; said stationary and rotatable structures including housing positioning and rotation limiting means comprising first detent means on said stationary structure and second detent means movable with said shaft and located adjacent the first means for cooperation therewith to position and limit movement of said shaft and said housing in different operative positions; and resilient means connecting said shaft and said stationary structure to etfect engagement of said first and second detent means in positions corresponding to different operative positions of the transducer relative to said different types of records.

References Cited in the file of this patent UNITED STATES PATENTS 1,856,069 Dina May 3, 1932 1,992,893 Thomas Feb. 26, 1935 2,570,578 Martin Oct. 9, 1951 2,572,712 Fisher Oct. 23, 1951 2,578,866 Vistain Jr Dec. 18, 1951 2,601,126 Palo et a1 June 17, 1952

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