US1742364A - Resistance control device - Google Patents

Description

Jan. 7, 1930., G. `LMEUER ET AL.

RESISTANCE CONTROL DEVICE y Filedovot, 5, 1925 Si l lgfz/ENroRs.I l, Mlm/m GSV/wem,

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PUNITED STATES PATENT v4orf-1:2151

@maar 3.1mm um wmnun O. STEVENS, Ol' HILWAUKEE, WISCONSIN, ABSIGNOBS, BY im .LBBIGNIENT TO OUTLEB-HAHHER, INC., A CORPORATION OIvDELA..

waterman connor.. 'nnvron Application. led October 5, 1985. Serial No. 00,391.

This invention relates to improvements in resistance control devices of the type -employed in radio and similar aparatus.

An object of the invention is to provide a resistance control device of simple and durable construction l Another object is to facilitate assembly of the several elements of the device.

Another object is to provide interchangeable elements whereby the electrical characteristics of the device may be altered as desired.

Another objectv is to provide novel means for removably securing, the device to a panel or other sup ort. v

Another object is to provide improved supporting and securing means for the resistance elements of devices of this character.

Other objects and advantages of the invention will hereinafter ap ear.

In the accompanyin rawin wherein are illustrated certain of t 1e embo ents which the'invention may assume in practice,

Figure 1 is a vertical 'sectional .view of a radio rheostat constructed in accordance with my'invention;

Fig. 2 is a rear elevational view of the device shown in Fig. 1; y

Fig. 3 is a vertical sectional view of a modiiiedform of-the device illustrated in Fig. 1, whereby the same is adapted for use as a potentiometer;

Fig. 4 is a rear elevational view of the device shown in Fig. 3; and,

Fig. 5 is a sectional view on the line 5-5 of Fig. 3.

Re erring to Fi 1 and 2 of the drawin the numeral 10 signatesa metallic hu member havin a reduced end portion 11 of a size correspon 'ng to the size of opening 12 in a metallic member 13. The member 13 abuts a shoulder 14-on hub member 10, and the end portion 11 of the latter is adapted to be spun' or riveted over the member 13, as indicated at 15, to secure said arts against relative movement. Huby member 10 `is internally vscrew-threaded, as indicated at 16,v

' to receive an externally screw-threaded cooperative clamping member 17 The membersv 1n centering the same within the perforation,

and also to insure a proper clamping action of said members.

Rotatabl mounted upon the hub member 10 is a su stantially cylindrical insulating base member 21, the latter having an annular projecting portion 22 (Figs. 1 and 5), which is provided with a groove 23. Groove 23 is concentrically disposed within the annular 'po'lecting portion 22, whereas the continuity e former is interrupted as indicated-at 24 to provide abutments 25 and 26 for engagement with a stationary projection 27 upon the member 13. Rotary lmovement ofbase member 21 is thus limited for a purpose hereinafter set forth.

The base member 21 is also provided with a peripheral cut-away portion 28 to receive the resistance element 29, the annular shoulder 30 being adapted to definitely position said element with respect to the base. As shown, said resistance element comprises a flexible strip of insulating material' 31 around which a suitable number of turns of relatively ne wire 32 are Wound in closely adjacent relationship to each other. Each .end of the wire 32 is'preferabl threaded one or more -times through' suita le openings 33 and 34 near the respective ends of the strip to prevent slippage or unwinding of the wire, whereas one end thereof leads oil from the wound portion as indicated in dotted lines at '35 (Fig. 2).I

The rear face of base member 21 is provided' with a notch or recess 36 to receive a .substantially U-,shaped metallic member 37 the reduced end portions 38 and 39 of the latter being adapted to pass through corresponding openings in the ends offlexible strip 31,"whereas said ends 38 Aand 39 are thereafter bent, as shown in Fig. 2, to hold the ends of'said strip in the desired position. In practice the arms of the U-shaped member 37 are preferably brought suiiciently close together to provide a slightly reduced circumference of the completed resistance element whereby the latter is required to be sprung over'the cut-away portion 28 of thel 42 of a disk-shaped member 43. Member 43 is provided with a central opening 44 and a pair of tongues or projections 45 adapted to take within a corresponding slot 46 in the reduced end 47 of a tubular member 48. Wire 35 is adapted to be laid in 'slot 46, and the same is clamped therein by said tongues 45,

Vthe reduced end 47 being thereafter riveted or bent over the member 43, as indicated at 49', to hold said parts together, with the spring fingers 42 compressed. The'member 43 therefore tends to draw the member 48 backwardly, but such movement is limited by y engagement of a shoulder 50 on the latter with the annular internal flange 51 on hub member '10. Moreover, this arrangement insures positive electrical engagement between member 48 and hub member 10. Member 48 is freely rotatable within the member 17, whereas the former is provided with a screwthreaded portion 52 for engagement by a correspondingly threaded insert 53 in a molded knob or handle '54.` A pointer or indicator 55 is'also preferably threaded onto portion 52 prior to the knob 54, whereby said polnter and knob may act as lock nuts with respect to each other to bind or lock the same to member 48.' It will thus be seen that rotary move? ment of knob 54 in one direction or the other will effect corresponding movement of theresistance element 29, due tothe interlocking connections .aforedescribed The member 13 is provided with an enlarged rearwardly bent portion 56 of arcshape, said member being perforated as indl- A cated at 57 to facilitate such bending thereof.

The arc-shaped portion 56 is. provlded with a plurality of rforations 58, 59 and 60, whereas `each 0in-)said openings is provided with an insulating lining by means of the annular in-bent flanges 61 on an insulating strip 62, as clearly shown in Fig. 1. A screw 63 passes upwardlythrough insulated opening 60, and a washer 64 of brass or other conducting material is placed thereover. A nut 65 1s threaded onto said'screw to hold the same in position. As will be apparent the screw 63 is in electrical] conductive relation to portion 56 of memb r 13. Screw 63 is therefore adapted to serve as one of the circuit terminals, a nut 66 being provided for clamping the circuit wire thereto.

A screw 67 passes through the insulated opening 58 at the opposite end of portion 56, said screw being in electrical contact with and adapted to support an elongated contact member 68. An insulating washer 69 is placed over' the upper end of screw 67 and the several parts are heldin position by the nut 70. It will thus be seen that screw 67 is completely insulated from portion 56 of member 13. A nut 71 is adapted to provide for con- -nection of the otherfwire of the circuit. The

intermediate opening 59 in portion 56 is not utilized Iin the arrangement illustrated in Figs. l and 2,'-the'same beiner adapted to facilitate the circuit connections lllustrated yin Figs. 3, 4 and 5 as hereinafter described.

Contact member 68 is preferably provided with a relativelyl narrow inward projectlon or rib 72 for engagement with the coils of resistance wire 32. `The liexible strip 31 is also preferably provided with a boss orprojection 7 3 for engagement with rib 72, asshown, to insure disengagement of the latter'from wire v32 when the parts are in the position ill'ustrated in Fig. 2. In said position circuit is interrupted, whereas upon turning of knob 54 in a clockwise direction circuit is completed, to first include all of the resistance and then gradually exclude the same upon continued clockwise movement of said knob.,

Such clockwise movement of the knob and its associated elements is limited by engagement of the shoulder 25 with projection 27 (shown in dotted lines in Fig. 2), at which time a minimum amount of resistance is included in circuit.

Assuming attachment of the circuit wires to screws 67 and 63 by means of nuts 71 and 66, respectively, and further assuming movement of knob 54 so that contact member 68 engages the resistance wire 32, continuity of circuit may be traced from screw 67 through contact member 68, through the resistance wire 32 from the point of contact of said member 68 to the end 35 of said wire, thence through tubular member 48 to hub member 10, to member 13 and portion 56, through metallic Washerf64 and nut 65 to screw 63,

and thence to the circuit wire connected to the latter. l

The device illustrated in Figs.' 3, 4 and 5 is in many respects identical with thatshown in Figs. 1 and 2, certain changes and additions being incorporated, however, to adapt the same for use as a potentiometer. Thus, Ithe resistance element 29m preferably comprises a relatively wider flexible insulating strip V31 upn which is wound a wire 32L which is finer than that employed in the device of Figs. 1 and 2. Moreover said wire is wound more closely adjacent to the ends of the iiexible strip 31* so that the member 68 is in electrical one end of the resistance wire 32 iswound v Yand fastened by solderin as indicated at 7 6 (Fig. The other en 35 of said wire is connected as described in connection withi in engagement with said ring Figs. 1 and 2. A screw 77 passesthroughthe intermediate insulated o ening 59 in portion 56, said screw being in e ectrical engagement with and adapted to support a yoke-shaped contact' element'or brush 7 8, the curved arms 79 and 80 of the latter being in alinement with contact ring 74 and provided with small bosses or projections 81 and 82 which are held An insulating washer 83 rovides for comp ete insulation of screw 77 rom portion 56, Whereas a nut 84 is adapted to hold the screw and its associated parts in position. A nut 85 provides for conneet-ion ci a 'circuit Wire in electrical engagement with the screvv 77. The device illustrated in Fi s. 3 to 5 is otherwise exactlylilre that shown 1n Figs.. i and 2, and further description thereof 1s deemed unnecessary,

With each of screws 63, 77 and 67 suitably connected incircuit by means oi the nuts 66,

y85 and 7l, respectively, continuityof circuit may be traced from the screvvf(` through contact 68 to a given point in the resistance element, thence in one direction to the lead Wire 35, through member i8, hub 10, member i3 and portion 56 'to screw 63, as set'iorth in connection with Figs. l and 2. An additional circuit is herein provided, 'Which may be traced from. said contact 68 through the remainder of the resistance wire to the ring 7 Li, thence through the brush or contacter 78 to screw 77. By the arrangement aforedescribed the Well known potentiometer circuit connections may be'efected.

The manner of assembling the respective devices Will be apparent from the foregoing descri tion. It may be further noted, h0wever, t at after spinning over or riveting the vreduced end i7 of member 48` as indicated at lines at 86 in said gurc, this feature being omitted from` the other iigures for clarity of illustration. l l In practice different sized wires 32 are ernployed` for providing resistance elements of di'erent ohmic values, whereas the ohmic value of a particular resistance element is' preferably markedv upon an uncovered portion of the fiexible insulating strip 31 after winding of the resistance Wire. When coated Wire is employed fforthe resistance elements such coating is preferably removed from the upper surface o such elements to insure good delectrical contact with the member 68.

what I claim andv dem a secure by Lertcrs Patent is: v

l .1. Iin resistance control apparatus, the combination with aA metallic hub` member, of a metallicterminal supporting member rigidlfysecured thereto, a headed member adapted r screw-threaded engagement with said huh ber, means at oneend of- .said shaftf for effecting rotation thereof, and means at the other end of said shaft for-positively` engag ing. said insulating block.

2. In resistance control apparatus, the combination with ametallic hub member, of a metallic terminal supporting member rigs idly secured thereto,a headed member adapt-1 ed for screw-threaded engagement with said hub member for' attachment of the latter to anl insulating panel or other sup ort, a substantially cylindrical insulatin block rotatably mounted on said hub mem er, an operating shaft axially penetratinglsaid headed member, means at one end of said shaft for eifecting rotation thereof, means at theV other end of said shaft for positively engaging insulating bloclr, and a resistance element frictionally secured to said block for rotation stantially cylindrical insulating lock rotatl ably mounted on said hub member, an oper atin shaft axially penetrating saidheaded mem er, ineans at one end of said shaft Jfor effecting rotation thereof` means at the other end of said shaft for positively engaging said insulating block, a resistance element )frictionally secured to said block for rotation therewith, one end of said resistance element r, an operating :shaft axlally penetrating said headed membeing electrically connected with said terminal supporting member through said shaftV and sal hub member, and a contacter sup! ported by but insulated from said terminal supportn adapted' or sliding engagement with `sai element.

4.1m resistance control apparatus, the combination with a metallic hub member, of a metallic terminal supporting member rigidly secured thereto, 'a headed member adapted for screw-threaded engagement with said hub member for attachment of the latter toy an insulating panell or other support, a substantially cylindrical insulatin block rotatably mounted on said hubmem er, an operating shaft axially penetrating said headed mem member, said contactorbein i `stantially cy indrical insulating in rotation thereof, means at the other end of said shaft for positively engaging said insulating block, a resistance element frictionally secured to said block for rotation therewith, one end of said resistance element being electrically connected with said terminal supporting member through said shaft and said hub member, a metallic ring electrically connected with the other end of said element, and a contact element carried byv but insulated from .said terminal supporting member for engagement with said ring.

5. In resistance control apparatus, the combination with a metallic hub member, of a metallic terminal supporting member rigidly secured thereto, a v eaded member adapted for screw-threaded-engagement with said hub member for attachment of the latter to an insulatin panel or other suiport, a subock rotatably mounted onsaid hub member, an operating shaft axially penetrating said headed member, means at one'end of said shaft for eecting'rotation thereof, means at the other -end of said shaft for positively engaging said insulating block, a resistance element securedy to said block for rotation therewith, one end of said resistance element being electrically connected with said terminal supporting member through said shaft and said hub member, va metallic ring electrically connected with the other end of said element, a contact element adapted for engagement with said ring, and a contactor adapted for engagement with said resistance element, said Contact element andv contactor being respectively supported by but insulated from said terminal supporting member.

6. In resistance control apparatus, the combination with a metallic hub member, of a metallic terminal supporting member of substantially L-shape in cross-section rigidly secured thereto, a' plurality of binding posts carried by said supporting member, certain of said binding posts being insulated therefrom, contactors carried by said last men! tioned binding posts, an insulating block rotatably mounted on said hub member, a contact ring carried by said block and adapted for engagement with one 0f said contactors, a resistance element peripherally mounted on said block for rotation'therewith and adapted for engagement with the other of said contactors, said element comprising a flexible insulating strip having wire wound thereabout, a metallic link for biasing the ends of said strip toward each other, means for electrically connecting one end of said wire and said ring, and means for electin i continuity of circuit between theother endo said wire and said terminal supporting lmeans, said means comprising an operating shaft in contact with said wire and said hub member.

7. In resistance control apparatus, the

combination witha metallic hub member, of-

a metallic terminal supporting member of substantially L-shape in cross-section rigidly secured thereto, a plurality of binding posts carried by said supporting member, certain of said binding posts being-insulated therefrom, contactors carried by said last mentioned'binding posts, an insulatin block rotatabl mounted on saidhub mem er, a contact ring carried by said block and adapted for engagement with one of said contactors. a

resistance element peripherally mounted on said block for rotation therewith and adapted for engagement with the other of said contactors, said element comprising a fiexible insulating strip having wire wound thereabout, a metallic link for biasing the ends of said strip toward each other, means for electrically connecting one end of said wire and said ring, means for effecting continuity of circuit between the other end of said wire and said terminal supporting means, said means comprising an operatin shaft in contact with said wire and said hu member, and a disk-shaped member riveted to said shaft,

said member having a plurality of inwardly extending resilient projections adapted for engagement with co-operative abutments on said block for effecting rotation of the latter.

8. In a resistance control device, the combination with a fixed hub member, of an insulating block rotatably carried thereby, means carried by said hub member for limiting rotary movement of said block in each direction, a rotatable shaft extending through said hub member, and means on said shaft adapted to positively engage cooperatin projections on the rear endof said bloc for effecting rotary movement of the latter.

9. In a resistance control device, the combination with a fixed hub member, of an insulating block rotatably carried thereby, a rotatable shaft extending through said hub member, and resilient means on said shaft having radial arms adapted for positive interlocking engagement with cooperating projections on said block for effecting rotary movement of the latter, said means being also adapted .to effect positive electrical engagelient between said shaft and said hub memer. Y

10. In a resistance control device, the combination with a fixed hub member, of an insulating block rotatabl carried thereby, means carried by said huh member for limiting rotary movement of said block in each direction, a rotatable shaft extending through said hub member, and' means on said shaft adapted to positively engage vsaid block for eiecting rotary movement of the latter, said means comprising a disk-shaped member having a plurality ofradial arms adapted to glligalge corresponding projections on said 11. In a resistance control device, the combination with a metallic hub member having a metallic terminal supporting member rigidly secured thereto, of means for rigidly securing said hub member to a panel or other support, an insulating block rotatably mounted on said hub member, means comprising a metallic shaft penetratingsaid hub member for eiecting rotary movement of said. block with respect t0 said hub member, means for limiting such movement of the block, a resistance element comprising a wire-wound flexible insulating strip, a said element being circumferentially arranged on and riction ally secured to said block, one end of said resistance element being electrically connected to said shaft, and a contactor adapted to engage said element, said contactor being carried by but insulated from said terminall supporting member.`

12. In a resistance control device, the combination with a metallic hub member having a metallic terminal supporting member rig idly secured thereto, of means for rigidly securing said hub member to a panel or other support, an insulating blck rotatably mounted on said hub member, means comprising a metallic shaft penetrating said hub member for effecting rotary movement of said block with respect to said hub member, means for limiting such movement of the block, a resistance element comprising a wire-wound flexibletinsulating strip, said element being circumferentially arranged on and rictionally secured to 1said block, one end of said resist ance element being electrically connected to I said shaft, terminals carried by said terminal supporting member, one of said. terminals,

being in electrical enga ement therewith, an-

other of said terminals eing insulated therefrom, and' a contactor carried by said last mentioned terminal, said contacter being adapted for engagement with said element.

13. In a resistance control device, the combination with a substantially cylindrical vinsulating block, o'f a resistance element comprising a strip of exible insulating material having a wire 'Qvound thereabout, said element being bent around said block, and means comprising a self-sustaining inwardly bowed resilient metallic member having hooked ends penetrating corresponding openings in the ends of said strip to bias'the latter toward each other solely byv the resiliency of said member and thereby frictionally holdvsaid element against movement axially of said block, said member being adaptedl to fit loosely within a notch in said block to prevent relative rotary movement of said element .and

said block. i

14. A resistance element comprising a iiexible strip of insulating material having a resistance wire wound thereabout, said strip being bent to forma circle'of predetermined

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