US2859319A - Phasing sectional gang potentiometer - Google Patents

Description

Nov. 4, 1958 F. H. mu es PHASING SECTIONAL GANG POTENTIOMETER Filed May 5, 1956 JNVENTOR.

FRED H. KARG BY Z ATTORNEY v om mw 8 ww om mm mw o. w mm mv N mum aw w vm mm 6 5 n 5 om om mm 9 Q S Q t w on W aw PM .2 3 8 3 WM 2 9 m: .2 8 o 2 am gm 2 mm m) 3 Q H IIMIW, I -iI 1 l4 I 41 HHHH i i, ill m. In 1 i 4 id x: r x 2 1 rmm mm fi. mm 3 1 a g a illill 1i Q 5 I! 1 f 9 I .V -V 1 mm WV. 0 Y \w nv mv mv m United States Patent 'Oihce PHASING SECTIONAL GANG POTENTIOMETER Fred H. Karg, Burbank, Calif., assignor to Topp Indusgries Inc., Los Angeles, Calili, a corporation of Caliorma Application May 3, 1956, Serial No. 582,373

6 Claims. (Cl. 20163) This invention relates to potentiometers and has as its general object to provide a novel and improved potentiometer construction wherein a plurality of potentiometer units are connected together end to end on a common axis for actuation in unison by a common actuator shaft.

A primary object of the invention is to provide such a gang potentiometer having means for adjusting the phase relationship between the potentiometer units for facilitating incorporation of the gang in a computer or other electronic circuit utilizing such a gang of potentiometer units actuated in unison.

In general, the invention contemplates a plurality of potentiometer units each having its own individual casing in the form of a tubular section of a common casing for the gang, the individual sections being coupled to one another for relative rotatable adjustment about their common axis, thus to adjust the phasing between the potentiometer units. Internal clamping is utilized in the coupling connections.

A particular object is to provide such a potentiometer wherein the adjustment can be eifected easily and simply by release pressure applied to the heads of locking screw, accompanied by the application of rotative torque to the adjoining sections between which adjustment is to be effected.

A further object is to provide such a potentiometer wherein a fine adjustment can be attained.

Another object is to provide for a 360 degree range of phasing adjustment.

Another object is to minimize the effect of changes in temperature upon the coupling connections between the potentiometer units. 7

Another object is to provide a gang potentiometer which may be readily converted to one embodying more or fewer units by a simple operation of attaching or detaching units.

Other objects will become apparent in the ensuing specification and appended drawings in which:

Figure 1 is a side view, partially broken away and shown in section, of a gang potentiometer embodying the invention;

Figure 2 is a transverse sectional view thereof, taken on the line 2-2 of Figure 1;

Figure 3 is a transverse sectional view thereof, taken on the line 3-3 of Figure 1; and

Figure 4 is an enlarged detail sectional view of the resistance coil mounting.

Referring now to the drawing in detail, and in particular to Figure 1, I have shown therein, as an example of one form in which the invention may be embodied, a gang potentiometer embodying, in general, a front end potentiometer unit A, succeeding units B, C and D coupled thereto, and a rear end cap E closing the unit D.

Front end unit A and rear end cap E include end wall sections and 11, respectively, having counterbores in which are mounted bearings 12. An actuator shaft 13 extends through front end wall section 10 and is journalled in bearing 12. A conventional knob (not shown) may 2,859,319 iatented Nov. 4, 1958 Units B, C and D include respective tubular casing sections 19 having respective annular shoulders 17 (Fig. 4), skirts 18' projecting axially therefrom at the outer diameter thereof, and neck members 20 at the inner di-.

ameter thereof, projecting axially in the opposite direction and telescoped into the skirts 1 8, 18' of adjoining sections. The ends of the skirts are abutted against shoulders 21. The neck 20 and skirt 18 of each of the sections B, C, D are joined by an offset portion 22 defined between shoulders 17 and 21. Each neck member 20 has a cylindrical peripheral wall telescoped into the skirt portion 18 or 18 of an adjoining casing section with a fit that is sufiiciently snug to maintain coaxial alignment of the casing sections and sufiiciently loose to allow free relative rotation of the adjoining casing sections subject to the control of the clamping means hereinafter described.

Projecting axially from each neck member 20 is a plurality of circumferentially separated jaw segments 23 (preferably three 'or more) which have limited radial flexibility. The jaw segments 23 are of reduced thickness, being offset radially inwardly of the outer diameter of intermediate neck member 23, and terminating in lips 24 that are headed outwardly to a diameter normally slightly larger than (or approximately the same as) the outer diameter of neck member 20, but adapted to be spread so as to enter an annular channel 25 within the adjoining skirt 18 or 18, and to lock against a frusto conical wall 26 defining the adjacent side of such groove. The inclined surface of lip 24, extending from its outer diameter toward the reduced portion of the jaw segment 23, coacts with the inclined wall 26 to effect a camming action for drawing the end of skirt 18 or 18 tightly against the opposed shoulder 21 when the jaw segments are expanded. Such jamming of the ends of the skirts against the adjoining shoulders, plus the grip of lips 24 against walls 26, is effective to securely lock the casing sections against relative rotation.

For etfecting expansion of the jaw segments, I provide a series of expandible split ring actuators each including a body ring portion 27 loosely received within a respective skirt 18 or 18', an integral flange 28 of reduced outer diameter fitted loosely within an adjoining series of jaw segments 23 when unloaded, and a plurality (preferably three or more) of screws 29 rotatably extended through a respective skirt 18 or 18 and threaded into ring body 27. Screws 29, passing through openings in skirt 18 or 18 with sufiicient circumferential clearance to accommodate both expansion and contracting movements of the actuator ring, are operable, when rotated forwardly with their heads bearing agains the skirt body, to expand the actuator ring which, in turn, will expand the jaw segments into clamping engagement with the co acting wall 26. When the screws are backed off, the actuator ring restrains the jaw segments just sufficiently to maintain a connection resisting axial separation of the casing sections 19 while allowing relative rotation to pro vide for phasing adjustment. With the screws thus backed off to provide radial clearance between their heads and the skirt body, they may be engaged by the fingertips and, will transmit fingertip pressure to the actuator ring to contract it so as to release the jaw segments 23 for withdrawal from the coupled skirt 18 or 18.

..Each of the potentiometer units A, B, C and D includes a toroidal resistance element 36 carried by a mounting ring 31 of L-section which is mounted within a respective skirt 18 or 18 and axially positioned by abut ment against the adjoining shoulder 17 or 17. Ring 31 is lined with an insulator ring 32 providing a seat for resistance. element 30.

A" series of insulating hub elements 33, each encircled by aconductor collar 34, are mounted on shaft 13 within the respective resistance elements 3%. Each collar 34 carries a radial conductor arm 35 having an integral outer end portion 36 extending axially and apertured to provide a mounting for a conductor eyelet 37 in which is mounted a radially disposed brush or wiper fingerfifi. Brush 38 is tightly fitted in eyelet 37 so as' to maintain adequate conducting contact with resistancecoil 30; under thev light springloa'ding or arm portion 36, when adjusted prop'eriy againfstthe resistance coil, but can be adjusted axially in the eyelet 37 by the application of pressure, untilithe" proper position is attained. 'Such adjustment mayjbe utilized not only for initial setting but also for wear'compensation.

' Each'skirt 18; 18 has an arcuate opening 39 over which 'is mounted'a saddle 40 of insulating material secured by screws 41 and mounting respective terminal posts 42,43, 44. In terminal post 42 is mounted a wiper whisker 45 which engages a respective collar 34 in an annular groove 46 which restrains the Wiper from shifting axially. The wiper 45 is deflected laterally so as to be tension-loaded against the collar to maintain good conductive contact. Terminal posts 43, 44 are connected by conductors 47, 48 to respective ends of a respective resistance coil. Thus, the potentiometer units may be separately connected to respective units of an electrical apparatus, for simultaneous operation.

Iclaim:

1. In a phasing gang potentiometer: a plurality of annular casing sections, arranged end-to-end, certain of said sections each including a skirt at one end defining a counterbore, an intermediate neck of smaller'diameter at the other end, rotatably fitted within theskirt ofan adjoining section, and a circumferential array of circumatqrjringsand the respective casing sections for expanding sai'd 'actu'at'or rings to deflect said jaws outwardly to cause said lipstoenter said'grooves and thereby couple saidjsections together and lock them in any selected arrangement of'phasing. adjustment relative to one another.

'2; In a phasing gang potentiometer: a plurality of annular casing sections arranged end-to-end, and including end sections and intermediate sections, said intermediate sections each including a skirt at one end defining a counterbore, an intermediate neck of smaller diameter at the other end, rotatably fitted within the skirt of an adjoining section, and acircurnferential array of circumferentially separated flexible coupling jaws formed integrally with and projecting axially from the neck and terminating. in radially outwardly projecting lips, the adjoining skirts having internal annular grooves positioned to receive said lips; expansible split actuator rings disposed within the respective arrays of coupling jaws; actuator means acting between the respective actuator rings and the respective casing sections for expanding said actuator rings to deflect said jaws outwardly to cause said lips to enter said grooves and thereby couple said sections together and lock them in any selected arrangement of phasing adjustment relative to one another; a common adjustment shaft journalled in said end sections; wipers carried by said shaft and insulated therefrom; means providing separate conductor connections to the respective wipers; and respective resistor coils mounted in the respective casing sections and engaged by the respective wipers.

3. A potentiometer as defined in claim 2, wherein each casing section has an external end shoulder formed as an offset between its neck and skirt and in end-abutting engagement with the skirt of the adjoining section.

4. A potentiometer as defined in claim 3, wherein. each of said annular grooves has a frustoconical wall disposed toward the end of the respective skirt andeng-aged by the' jaw'lips of the adjoining .casingsection withv a camming action that is efiective to draw said skirt end snugly against the abutting shoulder of the adjoining casing section.

5. A potentiometer as defined in claim 1, wherein said actuator means comprise respective screws rotatably extending through respective skirts and threaded into respective actuator rings to draw them outwardly.

. 6. In a phasing gang potentiometer: a'plurality of annular casingsections arranged end-to-end and including end sectionsand intermediate.v section s, said intermediate sections'ea'ch including askirt at one .end defining a counterbore, an intermediate neck of smaller diameter at the other end, rotatably fitted within the-skirt of an adjoining section,'an'd a circumferential arrayfof circumferentially separated flexible coupling jaws formed integrally with and projecting axially from thel neck and terminating in radially outwardly projecting lips, the. adjoining skirt having internal annular grooves positioned to receive said lips; expansible split actuatonrings disposed vwithin the respective arrays of coupling jaws; actuator means acting between the respectiveact'uator rings and the respective casing sections for expanding .saidactuator rings to deflect said jaws outwardly to causejsaid lipsto enter said groovesandthereby couplesaidlsections together and locking them in any selectedarrangement of phasing adjustment relative .to one another; ,faIcomnion adjustment shaft journalledinthe end sections; wipers carried by said shaft and insulated therefrom;,n1eans pro viding separate conductor connections tothe'respective wipers; respective resistorfcoilslmounted in ther'espective casing sections and engaged by th'elrespective wipers; each of said intermediate casing sections having an internal end shoulder defined as an oflsetbetween the neck and skirt ofthe respectivev section; and insulatormounting rings of L-section abutted. against theres'pective internal shoulders and providing seats for the respective resistor coils.

References Cited in the ,fileofthis patent UNITED STATES PATENT S- ll5,906 Stine June .13, 1871 1,767,226 Pearson June 24, 1930 2,747,230 Burgess May 29, 1956

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