US2075972A - Remote control device - Google Patents

Description

April 6, 1937.

E. L. BARRETT 2,075,972 REMOTE CONTROL DEVICE Filed Nov. 8, 1933 l 2 Sheets-Sheet/l April 6, 1937. E. L. BARRETT REMOTE CONTROL DEVICE Filed NOV. 8, 1933 2 Sheets-Sheet 2 a ...Mw

am @j Patented Apr. 6, 1937 PATENT OFI-Ice REMOTE CONTROL DEVICE Edward L. Barrett, La

Grange, lll., assignor to Utah Radio Products Company, Chicago, Ill., a

corporation of Illinois Application November 8,

13 Claims.

The invention relates to remote control devices and particularly to devices which are especially adapted for controlling the operation of a radio receiving set from a distant point.

5 An obj-ect of the invention is to provide an improved device of this character embodying a novel and compact arrangement of partswhich provide a small, neat control unit capable of being operated with great ease and affording sensitive and lo accurate control of the set'.

Another object is to provide a device of this character having novel operating means in which rictional resistance to manipulation is largely eliminated.

A further object is to provide a device of the reciprocating iiexible' cable type which embodies, in connection with. said cable, a rotatable member engageable by said cable and arranged to confine the associated part of said cable against independent movement, whereby friction due to relative movement between the cable and a conning part is`v eliminated.

Another and more specific object is to provide a rotatable member for engagement with a flexible cable in. which a cable receiving groove is located in a side face of the rotatable member'.

In conjunction With the foregoing, another object is to provide novel means for guiding a cable into a receiving groove in a reciprocable member at an angle to the lineof reciprocation of the groove.

A further object residesV in the provision of a re'- mote control device invvhich a plurality of control mechanisms are compactly disposed substantially side by side for alternate or selective engagement by a commondriving member.

More specifically stated, another object is to provide a. pairof combined gear andy pulley elements, preferably of the internal ring gear type, which are rotatably mounted on a suitable base for operative engagement selectively by av manipulable pinion, said gears being, if desired, of different dimensions.

Afurther object is to provide, in a remote control device for radio receiving sets having adjustable instrumentalities, such as condensers and a volume control, and having a circuit controlling switch operatively associated with one of said instrumentalities, selectively manipulable means for adjusting either of said instrumentalities, and locking means associated in a novel manner with said manipulable' means and capable of automaticallyV locking the switch in circuit breaking condition.

Other objectsI and advantages will become aprie 1933, serai No. 697,146

parent in the following description and from the accompanyingV drawings, in which:

Figure 1 is ak somewhat diagrammatic view on a reduced scale illustrating a control device embodying the features oi the invention.

Fig. 2 is an axial section through the remote control mechanism and is taken along the line 2-2 of Fig. 1.

Fig. 3 is a sectionalV view taken at right angles to the section of Fig. 2 as indicated by the line 3 3 of Fig. 1.

Fig. i is an enlarged view in section showing a detail of the lockingY mechanism.

Figs. 5', 6, 7 and 8 are transverse sections through the control mechanism'taken as indicated by the lines 5 5, 6-6, T-l, and 8*---8'0f` Fig. 2;

Fig. 9 is an irregular section through the control mechanism to illustrateV the means for guiding the flexible elements into engagement with the actuating members and is takenr along the line --Soi Fig. 3.

Figs. 10' and 11` are irregular sections through the control mechanism on the condenser shaft' and onthe volume'control shaft respectively asindicated by the linesy Ill---Il'lVV and II-I IV of Fig. 1.

The general arrangement of elements, as shown in Fig. l, comprises briefly a remote control mechanism 2l) adapted to be secured at any suit' ableipoint which is convenient to the operator of the vehicle, such as,v the steering column 2|, said mechanism being operatively connected with one or more of the movable adjusting parts of a radio receiving set, generally indicatedat 22. In'thls4 instance, these parts are a rotatable condenser shaft 23Y and an actuating shaft 24'for the volume control rheostat or potentiometerr 25. The operators manipulation of a single knobA or finger piece 26 is effective, as will hereinafter become more clearly apparent, to control the position of adjustment ofthe condenser shaft or f the volurne control device.

Particular reference Will be had to Figs. v2., 3 and to 9, inclusive, in describing one preferred form of the remote control mechanism 20. The mechanism is housed in a suitable casing, preferably comprising. a Abase 21 and a cover' 28 detachably connected in any suitable manner. A bracket 29- on the outer side face of the base is provided for mounting the mechanism in place. The base is of. substantial thickness and the inner surfaceV thereof has two circular recesses 30 and 311 therein, each arranged to receive a rotatable member 32'-, 3?V respectively constituting'theV actuating or operating` member by. which theV con.-

denser and volume control shafts are adjustably driven.

Where, as in the present instance, the volume control shaft is one of the parts of the set to be adjusted, the rotatable member which is operatively connected to said shaft, in this instance the rotatable member 32, may be substantially smaller in diameter than the other member 33 which is connected with the condenser shaft. 'Ihis difference in diametric dimensions is best seen in Figs. 2, 5 and 8. The dimensions of the circular recesses 39 and 3'! correspondingly differ and are of such size that the rotatable members 32 and 33 are seated snugly yet rotatably in their respective recesses.

In this embodiment, the rotatable members 32, 33 are in the form of internal ring gears and the parts are arranged to permit these gears to be selectively or alternately actuated by a common pinion 34. To this end, the recesses 30, 3l and the rotatable members 32, 33 are so related that at one point the pitch diameters of the gear teeth lie in substantially the same tangential plane. The pinion 34 is rigid with a tubular shaft 35 which is reciprocably and rotatably supported from the base by such means as a fixed shaft 35a. Preferably, the shaft 35a extends through the outer gear 33 to provide a rm support within the shaft 35 and pinion when the outer gear 33 is engaged by the pinion. The supporting means for the pinion is disposed with respect to the tangential point of the pitch diameters to produce engagement of the pinion with the gear teeth on one or the other of the rotatable members 32, 33, this engagement being selected by axial reciprocation of the pinion. One end of the shaft 35 extends through the cover 28 to receive the finger piece 26.

The rotatable members 32, 33 are preferably assembled on the base in the following manner: The members are axially spaced and are located substantially side by side, with the smaller diametered member 32 positioned innermost of the base in the deepest recess 30. Substantially centrally of the base is an outstanding lug 36 which in cross section is in the form of a wide crescent (see Figs. 5, 7 and 8). 'I'he outside or larger arcuate periphery of the lug 36 provides a surface 31 (Fig. 5) over which the gear teeth of the smaller rotatable member 32 ride, while the smaller arcuate periphery defines, in part, a nest 38 for the pinion 34. Also outstanding from the base is a second but smaller crescent-shaped lug 39, the outer or convex surface of which is disposed for engagement with the gear teeth on the larger rotatable member 33. This lug is located substantially opposite the pinion 34. Interposed between the two rotatable members 32, 33 is an annular spacing ring 40 (Figs. 2, 3 and 5) which is held against rotation by such means as an interlocking nib and recess arrangement 4l. One of the functions of the spacing ring is to separate the rotatable members 32, 33 so that the pinion 34 cannot engage both of the rotatable members 32, 33 at the same time.

The parts are held in the above described relationship by a clamping plate 42 which is secured in overlying relation to the outer rotatable member 33 preferably by means of a small screw 43 engaging the lug 36. On the side of the plate 42 adjacent the base is a crescent-shaped boss 44 (Fig. 2) which fits inside the smaller lug 39 on the base, bears against the outer surface of the annular spacing ring 40, and completes the surface over which the gear teeth 0n. the rotatable member 33 ride. Such means as a pin 45 (Figs. 2, 5 and 6), on the lug 39, engaging an aperture 46 (Figs. 2 and 6) in the clamping plate designates the proper position of the plate and holds the plate against rotation. The clamping plate maintains the proper assembly of the parts but it is preferred to maintain the rotatable members under a slight resilient or yielding movement resisting force. Thus, at spaced points, in this instance three, the clamping plate 42 is peripherally recessed, as at 41 (Figs. 3 and 6), to expose portions of the underlying rotatable member 33.

A spider 48 of resilient material has a leg for each of the recesses 41, the ends of said legs being inwardly oiTset to bear against the exposed surface of the rotatable member 33. The spider may be suitably and adjustably secured in place by the screw 43 to exert a variable force directly against the outer rotatable member 33 and indirectly against the inner rotatable member 32. Preferably a washer 49 of fibrous material is seated in a rabbetted groove on the rotatable member 33 for engagement by the ends of the spider arms, which ends may have inturned prongs thereon perfecting the engagement. This washer produces a frictional resistance in opposition to movement of the rotatable member which may be varied by the screw 43, and serves to maintain the parts in any of the Various positions of adjustment.

The clamping plate 42 does not extend entirely to the periphery of the rotatable member 33 to clear an offset portion or flange 50 whichoverlies the margin of the recess 3| and is annularly grooved on its outer surface to receive a side edge of an indicating drum 5l. The conventional tuning indicia on the drum are visible through an aperture 52 (Figs. 2 and 5) located in the cover to face upwardly toward the operator when the mechanism is assembled on the steering column. A bracket 53 on the outer face of the clamping plate 42 supports a lamp 54 for illuminating the indicia on the drum. Preferably one side of the lamp circuit is grounded to the casing and a lead 55 (Figs. 3 and 5) constituting the other side of the circuit extends through a suitable bore 56 in the base and clamping plate.

Preferably, means is provided for holding the pinion 34 for operative engagement with one or the other of the rotatable members 32 and 33. As shown in Fig. 6, one form of such means comprises a socketed member 51 mounted on the clamping plate in support of a spring urged ball 58 or the like for engagement with either of a pair of annular grooves 59 (Fig. 2) on the pinion shaft 35. The bracket 53 and the support 51 may include upstanding posts fashioned for engagement by screws 66 (Figs. 3 and 6) which extend through the cover to secure it to the base.

The connections between the rotating members 32, 33 and the volume control and condenser shafts respectively are of the reciprocating cable type and comprise, as shown in Fig. 7, a flexible power transmitting element 6| (preferably a stranded cable), a helicoidal winding 62 which is flexible and snugly encircles the element 6|, and au outer protecting sheath 63 of fabric or the like.

The cables are connected with the rotating elements in such a manner as to eliminate the possible imposition of frictional resistance to movement on those portions of the cable which engage the rotatable members. The relationship between one rotating element (for example element 32) and its associated cable will be described, since substantially the same structure is employed for both rotatable members. As shown in Figs. 2 and 3, the rotating member 32 has aside face which runs in contact with the base of the circular recess in which said member is mounted. 'Ihis face of the member has a circular groove 64 (see also Fig. 7) therein which faces toward the `base of the recess and is dimensioned snugly to receive the end portion of the associated cable 6|. The end of the cable is secured to the rotatable member in any suitable manner.

The groove thus provides radially spaced walls, the inner one of which is a working surface about which the cable is wound when a pull is exerted on the cable by rotation of .the member, while the outer wall provides a working surface which restrains the flexible cable lagainst outward radial movement when a thrust force is imparted to the cable. The cables are held against lateral movement out of the groove by the opposed surface of lthe base. In connection with the rotatable member 33, it 'should be noted that the spacing ring 40 serves as an opposing face for preventing laterally outward movement of the cable from the groove throughout those portions of the rotatable member 33 which overlie the recess in which the rotatable member 32 is located.

The feature of this arrangement of parts is that the flexible cable is closely confined in its groove against independent movement relative to its associated rotatable member and that radial movement of the cable is prevented by means which moves with the cable. Consequently friction due to wipingof the cable across a stationary 'part does not occur and the operative relationship between the cable and the rotatable member is entirely frictionless.

Guide means is provided for directing the longitudinal movement of each cable into its respective groove and the preferred guide means includes a passageway which extends substantially tangentially of the groove and at an angle to the face of the rotatable member in which the groove is located. The preferred arrangement can best be seen in Fig. 9. The rear outer face of the base is. at an appropriate point (generally at the lower side of the base), cut away to provide an opening in the base of each recess 30, 3| and located opposite to the grooves 64 when the parts are assembled. Surfaces 65 on the base 21, which terminate at said openings, slope gently inwardly thereto. These surfaces 65 are in stepped relation so that they may communicate properly with their respective recesses.

A closure plate 66, capable of being detachably secured to the base as by one or more screws 61, has surfaces thereon which are complementary tol the sloping surfaces 65 and the surfaces are longitudinally grooved, as at 68, to provide passageways for the exible cables 6|. The grooves 68, when the parts are assembled, are directly alined with the grooves 64 in the rotatable members 32, 33 so that the cables are guided into and out of the grooves in the rotatable members substantially tangentially and at a gently sloping angle thereto. The cables, therefore, approach the groove 64 at angles to the lines of movement or reciprocation thereof and at the prop-er points are bent into engagement with said grooves. The cables are thus positively coniined against other than longitudinal movement whereby lost motion or back-lash is eliminated. For convenience the ends of the helicoidal winding and fabric which house the flexible cable may be securely clamped between the base 21 and the closure plate 66.

Each of the rotatable elements 32, 33 has an arcuate pin and slo-t arrangement for limiting the extent of rotation of said members. Thus, as shown in Fig. 8 the face vof the rotatable member 33 opposite the base of its recess 3| has an arcuate groove 69 therein which cooperates with a pin 1|]v formed o-n the base. The limiting means which is associa-ted with the rotatable member 32 also cooperates with the locking mechanism and for this reason the present structure,'as shown in IFig. 4, has an arcuate groove 1| located in the base of its recess 3B for cooperation with a pin 12 on the rotatable member 32,

The locking means, which is herein provided, is capable vof automatically locking the apparatus in its inoperative position. Radio receiving sets conventionally have a switch device 13 (Fig. l) associated with one ofthe .tuning elements (usually the volume control device) to break the power circuit when the tuning element reaches one limit fof movement. Herein the switch is vshown in its conventional association with the volume control device 25, which device, in the present instance, is controlled by the rotatable member 32. The stop pin 1.2 is positioned to engage one end of the arcuate groove 1| when the volume -control device has been turned to the position in which the switch is open. Reciprocably mounted in a bore in the base 21 is a,

plunger 14 having one end movable into and out of the path of the pin 12 and the other end eX- tending into a pocket 15 formed in the outer side i of the base adjacent to the bracket 29.

The end of the plunger 14 terminates in an l angular portion 16 located in the pocket. Such means as a leaf spring 11 bears against the angular portion 16 normally to urge the plungeryl' inwardly of the base. The plunger is so located that when the pin 12 is substantially in abutment with the end of the arcuate groove 1|, the end of the plunger `is disposed ,in front of the pin 12 to prevent movement thereof. vof the pin and plunger, which meet as the pin moves toward the vaforesaid end of the groove, are arcuate as indicated at 1-8 to allow the pin to move past the plunger.

A key slot 19, which traverses the angolari por-tion 16 of the plunger, is arranged to receive a key A8|) or similar device by which the plunger may be lifted and held with the end thereof clear of the slot 1|. This arrangement permits the operator to lock the receiving lset against unauthorized `use. Insertion of the key into the slot moves the plunger so that the rotatable member 32 may be actuated. Initial movement of said member closes the switch to establish the power circuit. When the operator wishes to shut off the receiving set, the key is withdrawn and the end of the plunger 14 enters the slot 1 I. Rotation of the member 32 to break the circuit through the switch moves the pin 12 past the end -of the plunger 14 and the mechanism is automatically locked in inoperative condition. .If desired, the key may be withdrawn after the receiving set has been placed in operative condition and reception controlled in the usual manner until .the operator turns the mechanism to break the circuit through the switch.

The reciprocatory movement which is imparted to the flexible cable 6| by the remote control mechanism 20 may be transmitted to the condenser shaft through a spring pulley structure The surfaces i similar to that shown in my earlier' Patent No. 1,926,256, issued September 12, 1933. However, an improved structure has been provided in the nature of a unitary attachment for facilitating assembly of the attendant parts on the condenser shaft and for reducing the amount of force required to rotate said shaft. This structure is shown in Fig. l, and particularly in Fig. 10.

The condenser shaft 23 projects through a side wall 8| of the receiving set chassis and through an auxiliary supporting plate 82 which is detachably secured to the wall 8|. A cup-like housing 83, which is secured to the shaft 23 through a hub 84, encloses a coil spring 85 having one end attached to the cup and the other end to a nib 86 struck out of the plate 82. The hub carries a segmental gear 81 meshing with a reduction pinion 88 which is rotatably supported on a stub shaft 89 fixed to the plate 82. The hub of the pinion 88 carries a peripherally grooved pulley 9D. The flexible cable 6I is dlrected into engagement with the pulley groove by means of a detachable clamp 9| carried by a bracket S2 on the plate 82, which holds the end of the helicoidal winding 62 adjacent and tangential with-respect to the pulley groove. The spring 85 is connected to exert its force in a direction which will exert a pull on the flexible cable 6 I, thus holding the cable taut and supplementing the thrust force which is transmitted to the cable by the rotatable member 33.

The volume control shaft 24 may be actuated by its flexible element 6| through substantially the same mechanism as has been described in connection with the condenser shaft. However, since the volume control shaft normally requires considerable operating force. an antifriction connection, resembling that between the rotating members 32, 33 and their associated cables. is preferably employed. Referring to Figs. l and 1l, the volume control shaft 24 extends from the casing which encloses the control through an externally screw threaded bushing 93. The outer end of the shaft carries a disk fixed thereto which has a circular groove 94 in one side face thereof. This groove receives the end portion of the flexible cable 6l which is suitably secured to the disk. A stationary plate 95 is mounted between lock nuts 96 on the bushing and is positioned closely in opposition to the open face of the groove to confine the iiexible cable therein. The plate has an annular bracket 81 thereon which slopes toward the groove in the disk and this bracket carries a detachable clamp 98 for securing the end of the helicoidal winding 62 in position to direct longitudinal movement of the flexible cable substantially tangentially and angularly into the groove. By this construction, the use of a spring for rotating the shaft 24 in one direction is unnecessary, since both end portions of the cable are so confined that a thrust force may be efiiciently transmitted to the controlled one of the rotating parts.

In describing the operation, it is assumed that the parts are properly assembled substantially as shown in Fig. 1 and that the mechanism is locked in inoperative condition. The operator inserts the key 88 to unlock the device and then by rotation of the finger piece 26 drives the rotatable member 32 which, through reciprocation of the associated iiexible element 6l, rotates the volume -contnol shaft 24 and moves the switch to close the power circuit. An outward pull on the knob 26 shifts the pinion 34 from a driving engagement with the rotatable member 32 into a similar engagement with the rotatable member 33. Rotation of the finger piece 26 will now effect an adjustment of the condenser shaft 23 to position the condensers at any desired point. The finger piece 26 may then be shifted inwardly to adjust volume. When the operator wishes to discontinue reception, the key is withdrawn and the volume control shaft rotated until the circuit through the switch is broken. As this operation takes place, the device becomes automatically locked against further operation. Of course, if the operator merely wishes to discontinue reception temporarily, the key need not be withdrawn.

It will be evident from the foregoing that a novel remote control device has been provided which embodies an improved relationship of parts by which the tuning manipulation may be accomplished with the utmost ease. Frictional resistance of relatively moving parts has been so largely eliminated that the mechanism is manipulable with no more eort than-would be required in the direct operation of the tuning devices.

I claim as my invention:

1. A control device comprising, in combination, a base having a recess therein, a pair of rotatable members mounted in said recess for movement relative to each other and to said base, each of said members having an annular groove in a side face thereof, a pair of flexible power transmitting elements, guide means on said base for directing the movement of said power transmitting elements into said grooves, said rotatable members having gear teeth thereon and being arranged so that said gear teeth are alined at least at one point, and an actuating pinion selectively engageable with the gear teeth on one or another of said elements at said point.

2. A control device comprising, in combination, a base having a recess therein, a pair of internal ring gears mounted in said recess for movement relative to each other and to said base, each of said ring gears having an annular groove in a side face thereof, a pair of flexible power transmitting elements, guide means on said base for directing the movement of said power transmitting elements into said grooves, the gear teeth on said gears being alined at least an actuating pinion selectively engageable with the gear teeth on one or another of said elements at said point.

3. A control device comprising, a base, a pair of for movement relative to each other and to said base, each of said members having a base opposing groove therein, a pair of iiexible power transmitting elements, guide means on said base for directing the movement of said power transmitting elements into said grooves, said members having gear teeth thereon arranged in alinement at least at one point, and an actuating pinion selectively engageable with the gear teeth on one or another of said elements at said point.

4. In a remote control device for radio receiving sets adapted for installation in a vehicle, the combination with a volume control device in said set having a rotatable adjusting shaft, of a disk secured to said shaft having a groove in a flat face thereof, a non-rotatable plate opposing said groove and having means thereon defining a passageway communicating with said groove, a remotely positioned member mounted for rotation and having a groove in a flat face thereof, means in combination,

at one point, and

members mounted on said base opposing said groove and having a passageway therein communicating with said groove, a flexible power transmitting element having its end portions extending through said passageways and secured respectively to said disk and to said remotely positioned member, and a flexible guide tube enclosing said powertransmitting element and rigidly connected to communicate at its opposite ends with said passageways.

5. A remote control device comprising a housing having a base adap-ted to be secured to a supporting member and within said housing having a pair of circular recesses of diierent diameters, an internal ring gear seated in each recess, said recesses being alined so that at one point the pitch diameters or" said gears are substantially in the same tangential plane, a pinion having a supporting shaft journaled in said base for axial movement and so located with respect to said point that said pinion may be selectively engaged with one or the other of said gears, a exible power transmitting element for each gear, said gears having grooves therein for receiving variable lengths of said flexible elements, and guide means on said base for directing longitudinal movements of said elements into and out of said grooves.

6. A remote control device comprising a. housing having a base adapted to be secured to a supporting member, a pair oi gears disposed side by side and movably mounted on said base, a pinion having a tubular supporting shaft, a stub shaft rigid with said base and receivable in said tubular` shaft to support said tubular shaft and pinion whereby the pinion may be selectively engaged with one or the other of said gears and is rigidly supported in either position, a flexible power transmitting element for each gear, said gears having grooves therein for receiving variable lengths of said exible elements, and guide means on said base for directing longitudinal movements of said elements into and out of said grooves.

7. A remote control device comprising a housing having a base adapted to be secured to a supporting member and within said housing having A a pair of circular recesses, internal ring gears seated in said recesses, a driving pinion for selective engagement with either ring gear, spacing means between said gears to prevent simultaneous engagement by said pinion, a clamping plate for holding the parts assembled, stationary means defining nests in which said gears and pinion rotate, and iiexible means for transmitting the movement of said gears to parts to be controlled.

8. A remote control device comprising a housing having a base adapted to be secured to a supporting member and within said housing having a pair oi circular recesses, internal ring gears seated in said recesses, a driving pinion for selective engagement with either ring gear, clamping means for holding said gears assembled, adjustable means for imposing resistance to movement on said gears including a friction washer bearing against one of said gears and resilient means bearing against said washer, and flexible means for transmitting the movement of said gears to parts to be controlled.

9. In a remote control device for radio receiving sets, a unitary assembly for establishing an operative connection with the condenser shaft comprising, in combination, a plate for attachment to a stationary part of the receiving set, a shaft ixed on said plate, a pulley disk on said shaft for connection with a power transmitting element from a control mechanism, a pinion rigid with said pulley disk, a housing having a gear meshing with said pinion, means for attaching said housing to the condenser shaft, and a spring in said housing connected to exert its force between said housing and said plate.

10. A control device comprising, in combination, a base having a recess therein, a pair of rotatable members mounted in said recess for movement relative to each other and to said base, a pair of flexible power transmitting elements respectively connected to said rotatable members, means selectively engageable with said rotatable members for relative movement of one of the members at a time, one of said members having av peripheral portion overlapping the edge of said base defining said recess, and indicia means on said overlapping portion for visually indicating the relative adjusted position of said one member.

11. A remote control device comprising, in combination, a base, means on one side of said base for connecting the same to a support, a pair of rotatable members mounted on the opposite side of said base, a shaft journaled in said base and including means selectively engageable with said rotatable members for relatively rotating the same, a manipulable member on said shaft for effecting such selective engagement, means connected with each of said rotatable members for connection with remotely positioned devices to be controlled, and lock means for preventing movement in one position of one of said rotatable members and extending through said base and operable from the rst mentioned side thereof.

12. In a remote control device, the combination of a base including means on one side for securing the base to a supporting structure, said base having a recess in the side opposite said means and an aperture communicating through the base with said recess, a. rotatable member mounted in said recess for movement relative to said base and having a groove therein opening in a direction paralleling the axis of said member and in assembly opposed to the base of said recess, said groove being in registration with said aperture at all points of rotation of said member, a flexible power transmitting element passing through said aperture into said groove and being secured to said member for slidable movement through said aperture as an incident to movement of said member, and means for moving said member.

13. In a remote control device, the combination of a base including means on one side for securing the base to a supporting structure, said base having a recess in the side opposite said means and an aperture communicating through the base with said recess, a rotatable member mounted in said recess for movement relative to said base and having a groove therein opening in a direction paralleling the axis of said member and in assembly opposed to the base of said recess, said groove being in registration with said aperture at al1 points of rotation of said member, a exible power transmitting element passing through said aperture into said groove and being secured to said member for slidable movement through said aperture as an incident to movement of said member, gear teeth on the periphery of said member, and an actuating pinion engaging said gear teeth and having operating means coacting therewith for rotating the pinion to drive said member and move said flexible element relative to said base.

EDWARD L. BARRETT.

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