US2968015A

US2968015A - Phasable ganged potentiometer

Info

Publication number: US2968015A
Application number: US752912A
Authority: US
Inventors: Blanco Elias
Original assignee: Daystrom Inc
Current assignee: Daystrom Inc
Priority date: 1958-08-04
Filing date: 1958-08-04
Publication date: 1961-01-10
Anticipated expiration: 1978-01-10
Also published as: CH364021A

Description

Jan. 10, 1961 EL M S 51 All (0,

INVENTOR.

16554,? luup,

United States Patent F PHASABLE GANGED POTENTIQMETER Elias Blanca, Los Angeles, Calif assignmto Daystrom, Incorporated, Murray Hill, N.J., a corporation of New Jer y Filed Aug. 4, 195,8, Ser. No. 752,912.

13. Claims,- (Cl. 338-135) The present invention relates generally to variable resistors or potentiometers, and is more particularly concerned with devices of this type which may be built inminiature or extremely small size units, and which may be utilized singly or ganged together.

Heretofore, potentiometer units have been ganged by securing the casings together by means of clamping rings which would permit individual units to be phased by shifting of the respective casings. This necessitated a loosening of the ganged assembly and necessitated a readjustment of the phasing of each unit and a recheck before the clamping rings were again tightened. The conventional constructions were very inconvenient and hard to adjust. Moreover since the terminals for each casing were in fixed relation to the casing, shifting of the casings during phasing also resulted in a shifting of the terminals. It was therefore difficult .to use a pro-assembled wiring harness with the conventional arrangements.

Having in mind the inherent disadvantages of conventional constructions, it is a primary object of the present invention to provide a novel potentiometer unit which is so arranged that the casings may be secured in rigid relation, thus permitting the use of pre-assembled wiring harness, and wherein the units may be independently phased from the exterior of their respective casings.

it is a further object to provide in a potentiometer of the character described, an adjustable wiper contact which can be adjusted after the casings are assembled, thus making it unnecessary to have to calculate the wiper position prior to assembly.

Still another object is to provide a novel potentiometer construction, wherein the wiper contact is phasable through 360.

Still another object is to provide improved means for securing the potentiometer units in ganged relation in such a way as to result in less weight than gang potentio meters utilizing the heretofore known arrangements.

Further objects of the invention will be brought out in the following part of the specification, wherein detailed description is for the purpose of fully disclosing the invention without placing limitations thereon.

Referring to the accompanying drawings, which are for illustrative purposes only:

Fig. 1 is a perspective view of a ganged potentiometer embodying a plurality of potentiometer units constructed according to the present invention.

Fig. 2'is a longitudinal sectional view of an assembly embodying a single potentiometer unit;

Fig. 3 is a transverse sectional view taken substantially on line 33 of Fig. 2, portions being cut away to show the cooperative relationship of various parts of the device;

2,968,015 Patented Jan. 10, 1961 Fig. 4 is an enlarged fragmentary elevational view of the casing access opening seal, as viewed substantially in the direction of the arrow 4 of Fig. 3; and

Fig. 5 is a fragmentary sectional view illustrating the manner in which a plurality of potentiometers maybe secured together in ganged relation with their casings in end-to-end relation, according to the present invention.

Referring more specifically to Fig. 1 of the drawings, for illustrative purposes, a plurality of potentiometer units constructed in accordance with the present invention, as generally indicated at A, are shown as being secured together in end-to-end relation to form a ganged assembly operable by an actuating shaft 1t Referring primarily to Fig. 2, the construction of a single potentiometer unit will first be described. As shown in Fig. 2, the potentiometer unit comprises a main casing 1 of molded or otherwise formed plastic or other suitable material to provide a circular cup-like member which is open at one end and at the opposite end is formed with an inturned fian e 12, the inner periphery of which bounds a restricted end opening 13.

The shaft lit is rotatably supported in end caps 14 and i5 respectively which are secured to the opposite ends of the casing 11. The end cap 14 may be fabricated to accommodate the potentiometer for different types of mountings. For example, the end cap, 14 may be constructed for panel mounting. As shown herein, the cap provides a servo mounting, and is of generally ring-shaped configuration, being centrally formed with a tubular bearing support 16. The shaft in is rotatably supported in this end cap by antifriction bearing 17 having an outer race 18 which is secured and retained in the bearing support by a retaining ring 19, while the inner race 2%} is secured to the shaft between a pair of

snap rings

21 and 22, a spring washer 23 being interposed between one of these rings and the inner race of the antifriction bearing.

The end cap 14 is secured to the casing 111 at peripherially spaced points by means of a stud 24- which has its outer end threadedly engaged with the end cap, while the other end projects through an opening 25 of the casing 11 into a recess 26 where it threadedly engages one end of a threaded sleeve 27.

As will be seen in Fig. 2, the end cap 15 is centrally formed with an internal recess 28 within which antifriction bearing 29 is retained, the inner race 30 of this bearing being in engagement with the adjacent end of the shaft It), while the outer race 31 of the bearing is retained in the recess of the cap. The cap 15 is secured to the open end of the casing 11 by means of headed studs 32 which are adapted to extend through an opening in the cap 15 arranged to align with recess 26. The threaded end of the stud 32 threadedly engages into the adjacent end of the threaded sleeve 27. By tightening the studs 32, the cap 15 will be tightly engaged with the adjacent edge of the casing 11. With the foregoing arrangement, the potentiometer components within the casing 11 are enclosed and protected.

The potentiometer components include a resistance element 34 and an associated wiper contact 35. The resistance element is seated in an annular groove or recess 36 on the inner surface of the flange 12, and comprises a plurality of spiralled turns of resistance wire 37 which is wound over a supporting ring-like core member 38, suit- .able insulation 39 being interposed between the wire turns the core ends, so that the core structure may expand and contract under temperature changes.

The wiper contact is carried by the shaft and is assembled into a two-part supporting structure permitting movement of the wiper contact directly in response to shaft movements, and independent adjustment of the wiper contact in order to permit phasing or a change of relative position between the resistance element and wiper contact for a given shaft position. More specifically, the two-part supporting structure includes a first part 41 fabricated from a suitable plastic or other material to provide a circumferentially extending radially projecting flange portion 42 and an integrally formed hub portion 43 which surrounds the shaft 10 and is fixedly secured thereto as by a set screw 44. One side of the flange 42 is formed with an annular groove 45 for receiving one end of the second part 46 of the mounting structure for the wiper contact. The second part is generally ring-shaped and is rotatably mounted on the hub portion of the first part. The second part has an end 47, the end which is positioned in the groove 45, fabricated to form a ring gear with teeth 48 formed on its outer periphery. The other end of the second part 46 is formed with an outwardly projecting circumferentially extending flange 49 which is adapted to bear against the adjacent face of flange 42 so as to axially locate the end 47 within the groove 45.

As shown best in Fig. 3, the wiper contact 35 is constructed as an integral radially extending projection from a ring-shaped body portion 50 which surrounds the shaft and is positioned in face engagement on one side with the end surface of the flange 49. This assembly is retained in position and preloaded by means of a snap ring 51, and a spring washer 52 which bears against a metal Washer 53, an insulating spacer ring 54 being interposed between the washer 53 and the body portion 50 of the wiper contact element. In order to prevent relative circumferential movement of the wiper contact with respect to the second part 46 of the support structure, the surface of the second part which is in engagement with the body portion 50 of the wiper contact is provided with a socket 55 into which there extends a keyfinger 56 formed as a part of the wiper contact, thus locking the parts against relative circumferential movement.

Means are provided for relatively moving the first and second parts in a circumferential direction, and locking these parts in the adjusted position. This is accomplished by mounting a worm 57 in the flange 42, this worm being in meshed relation with the teeth 48 of the second part 46. The worm 57 is rotatably mounted in a drilled or otherwise formed passage 58 which has an open end 59 in the peripheral edge of the flange 42. The worm is longitudinally retained in the passage 58 by means of a keeper and groove interconnection as generally indicated by the numeral 60. The outer end of the worm member is shown as being provided with a socket 61 for receiving the end of a suitable tool by which the worm may be rotated, as will be more fully explained subsequently.

In order to permit the actuation of the worm 57 and the adjustment of the wiper contact, after the potentiometer is fully assembled and without having to disassemble the casing, the outer wall of the casing 11 is provided with a passage 62 which is directionally positioned in such a manner that the passage 58 may be brought into axial alignment therewith by turning the shaft 10 to proper position.

The outermost end of the passage 62 has an enlarged cylindrical portion 63 which is axially positioned in eccentric relation to the axis of passage 62. A sealing plug 64 is retained in rotatable seated position in the portion 63 by a groove and keeper as generally indicated at 65. The plug 64 has an off-center opening 66 which may be brought into and out of registration with the axis of passage 62 by inserting a small tool such as a screw driver into a receiving slot 67 in the outer end of the plug. By rotating the off-center opening into registration with the axis of the passage 62, a tool may be inserted into the socket 61 for moving the wiper contact to phase the potentiometer. After the adjustment is completed, the casing may then be sealednby the simple expedient of rotating the opening 66 to a position wherein the outer end of the passage 62 will be closed.

Connection terminals

68, 69 and 70 are supported in the outer wall of casing 11, as primarily shown in Fig. 3. These terminals are connected with the components of the potentiometer through permanently positioned eyelets 71, 72 and 73, each of the terminals being connected to an eyelet by means of a connector strip 74. As shown, the eyelets 71 and 72 are respectively connected to the ends of the resistance element, while the eyelet 73 connects with an eyelet 75, through a conductor 76. The eyelet 75 is utilized to secure a brush contact structure 77 in fixed position on the flange 12. The brush contact has oppositely extending spring arms 78' and 78" adapted to bear against and form a sliding contact with the adjacent surface of the body portion 50 of the wiper contact structure. With the arrangement described above, it will be appreciated that the wiper contact may be rotated by rotating the shaft 10 through a complete circle of 360, and that also by actuating the worm and gear, phasing of the wiper contact may likewise be accomplished through a complete circle of 360. Moreover, by utilizing a worm and gear arrangement for phasing, the wiper contact may be set at any position, and when so adjusted is locked against shifting movement by the inherent characteristics of the worm and gear drive.

One of the desirable features resulting from the potentiometer construction described above resides in the fact that the casing 11 may be constructed of shorter length than with conventional arrangements, and that a plurality of potentiometer units in their respective casings 11 may be secured in end-to-end axial alignment to produce a ganged assembly in which the respective wiper contacts may be phased after assembly by simply moving the shaft 10 to bring the actuating worms into proper position for adjustment through the passage 62 of each potentiometer casing.

The manner in which the casings 11 are interconnected is more or less schematically illustrated in Fig. 5, wherein two casings 11a and 11b are secured in ganged assembly. It will be appreciated, however, that the gang may include additional casings as desired, and Fig. 1 shows three casings ganged into a single unit.

For interconnecting additional casings, a straight stud 79 is used instead of a headed stud such as shown at 32. The outer end of the stud 79 connects with one end of the threaded sleeve 27 of the casing which is being added. To connect the end cap 15, a stud 32 is utilized in the same manner as previously described and shown in Fig. 2.

A great advantage in being able to phase the potentiometers after the casings are in assembled relation resides in the fact that the phasing may be accomplished with my construction without disturbing the position of the terminals, thus permitting the use of a pre-assembled wiring harness.

Various modifications may suggest themselves to those skilled in the art without departing from the spirit of my invention, and, hence, I do not wish to be restricted to the specific form shown or uses mentioned except to the extent indicated in the appended claims.

I claim:

1. A potentiometer, comprising: a casing; a ringshaped resistance element in said casing; a rotatable shaft extending axially of said resistance element and projecting from said casing; a slider contact carried by said shaft and movable thereby over said resistance element; and means for varying the angular position of said slider contactwith respect to said shaft, said means including a rotatable member having an axis of rotation at right angles to said shaft axis and being accessible for rotationfrom the casing exterior.

2. A potentiometer, comprising: a casing; a ringshaped resistance element in said casing; a rotatable shaft n said casing extending axially of said resistance element; a two-part support carried by said shaft including a first part affixed to the shaft for rotation therewith, and a second part movably supported on said first part for angularly variable positions of adjustment about the shaft axis; a slider contact carried by said second part movable over said resistance element; and a worm and gear interconnection between said parts operable to relatively vary their angular relationship with respect to the axis of said shaft, said interconnection being accessible for actuation through an opening in said casing.

3. A gang potentiometer, comprising: a plurality of potentiometer units secured in axial alignment within a casing structure, each of said units including a ringshaped resistance element concentrically disposed about a common actuating member; a wiper contact carried by said member; and means for circumferentially varying the angular position of the wiper contact with respect to said member, said means in each case being accessible from the casing exterior through an opening therein.

4. A gang potentiometer, comprising: a plurality of potentiometer units in axial alignment with their casings fixedly interconnected in end-to-end stacked relation; a rotatably supported shaft extending axially of said interconnected casings; a ring-shaped resistance element in each of said casings; a wiper contact in each of said casings carried by said shaft and movable thereby along said resistance element; exterior connection terminals carried by each casing having electrical connection with the resistance element and wiper contact therein; and means in each potentiometer unit for independently phasing said contact therein, while maintaining said axial alignment and the relative positions of the terminals of the units.

5. A gang potentiometer, comprising: a plurality of potentiometer units in axial alignment with their casings fixedly interconnected in end-to-end relation; a rotatably supported shaft extending axially of said interconnected casings; a ring-shaped resistance element in each of said casings; a wiper contact in each of said casings carried by said shaft and movable thereby along said resistance element; exterior connection terminals carried by each casing having electrical connection with the resistance element and wiper contact therein, said contacts of the respective potentiometer units being relatively fixedly positioned; and means accessible from the exterior of said casings for relatively phasing the wiper contacts of said potentiometer units, while maintaining said casings fixedly interconnected.

6. A gang potentiometer, comprising: a plurality of potentiometer units in axial alignment with their casings fixedly interconnected in end-to-end relation; a rotatably supported shaft extending axially of said interconnected casings; a ring-shaped resistance element in each of said casings; a wiper contact in each of said casings carried by said shaft and movable thereby along said resistance elements; exterior connection terminals carried by each casing having electrical connections with the resistance elements and wiper contact; means in each potentiometer casing for phasing the wiper contact therein including a rotatable member operable by. a tool insertable through a casing opening; and means for closing said opening.

7. A gang potentiometer, comprising: a plurality of potentiometer units secured in axial alignment, each of said units including a resistance element and a wiper contact, a common actuator for said units, and means accessible from the exterior of each of said units for independently varying the relationship between said wiper contact and associated resistance element, to vary the phase relationship between the respective units, while maintaining said units in their initial assembled ganged relationship. 0

8. A potentiometer, comprising: a casing; an elongate ring-shaped resistance element in said casing; rotatable wiper means having contact with said resistance element; rotatable actuating means for moving said wiper means to vary its contact position with said resistance element in accordance with movements of said actuating means, said actuating means and said wiper means having coincident axes of rotation; and manually operable adjusting means for independently varying the relative position of said wiper means with respect to said resistance element, while maintaining a fixed relationship between said actuating means and said casing, said adjusting means being operable to move the wiper means circumferentially of said axes through an angle of 360.

9. A potentiometer, comprising: an elongate ringshaped resistance element; a wiper contact member adjustably movable from one end to the other of said resistance element; first means for moving said contact member including an actuating member normally movable to adjust the position of said contact member between the ends of said resistance element in accordance with changes in position of the actuating member; and manually operable second means interconnecting said actuating member and said contact member adjustable to vary the position of said contact member from one end to the other of said resistance element, while maintaining the actuating member fixed, whereby the angular relationshfp between the actuating member and the contact member may be changed at will.

10. A potentiometer, comprising: a casing; a ringshaped resistance element in said casing; a rotatable shaft extending axially of said resistance element and said casing; a slider contact carried by said shaft and rotatable thereby over said resistance element; and phase adjusting means for varying the angular position of said slider contact circumferentially with respect to the axis of said shaft, said phase adjusting means being accessible from the exterior of said casing for change under operating conditions.

11. A potentiometer, comprising: a casing; a ringshaped resistance element in said casing; a rotatable shaft extending axially of said resistance element and said casing; a slider contact carried by said shaft and movable thereby over said resistance element through an angle of 360; and means for mounting said slider contact on said shaft for rotation therewith including parts cooperable to independently vary the angular position of said slider contact circumferentially with respect to the axis of said shaft through an angle of 360.

12. A potentiometer, comprising: a ring-shaped resistance element; a rotatable shaft extending axially of said resistance element; a two-part support carried by said shaft, one of said parts being aflixed to said shaft for rotation therewith, and the other of said parts being movably supported on said one of said parts for angularly variable positions of adjustment about the shaft axis; a slider contact carried by said other of said parts and being movable over said resistance element about an axis of rotation coincident with said shaft axis; and manually operable adjusting means for moving said other of said parts through 360 with respect to said one of said parts to vary its angular position with respect to said shaft and the position of said contact on said resistance element.

13. A potentiometer, comprising: a ring-shaped resistance element; a rotatable shaft extending axially of said resistance element; a two-part support carried by said shaft including a first part affixed to the shaft for rotating therewith, and a second part movably supported on said first part for angularly variable positions of ad justment about the shaft axis; a slider contact carried by said second part movable over said resistance element about an axis of rotation coincident with said shaft axis; and means for relatively rotating said first part and said second part to circumferentially vary its angular position with respect to said shaft and the position of said contact on said resistance element, including a worm and gear interconnection between said parts which coact to interlock said parts against relative movement when the parts are rotated as a unit by the shaft.

References Cited in the file of this patent UNITED STATES PATENTS I Pieper July 20, 1891 Stout Oct. 12, 1943 Canziani et al. Apr. 8, 1952 Barclay Oct. 27, 1953 Mucher Apr. 20, 1954