US1690077A - Variable control device - Google Patents

Description

Oct. 30, 1928. 1,690,077

L. a. PACENT VARIABLE CONTROL DEVICE Filed June 1923 INVENTOR BY I W M ATTORNEY and the like.

Patented 0a. 30, 1 928.

"U TED T TES 1,690,077 PATENT OFFICE.

Louise. racism, or WIN-FIE D, new YORK. assIGNoR 'ro rncnn'r ELECTRIC oom- Jenny, INC.,0F NEW YORKLN. Y., A conroanrron or NEW YORK.

VA RIA BLE oonrnor. mivron.

. j Application filed June a, 1923. Serial 116144.299;

Thisinventionhas to'do with ,devicesfor manually controll ng ElGCtIICal apparatus and more especially-"high frequency apparatus such asvariable condensers, variometers The invention relates, more particularly, to what are commonly termed Vernier adjust: ment devices and, specifically, to control knobs and dials provided with instrumentali' ties for. effecting very fine rotary adjustments of the electrical. apparatus to which it} may beattached. V

with highly a selective circuits adjustments areffreqnentlyso criticalth'at it is CllfllCll'lt to tune in desired transmitting stations with the control knobs ordinarily provided. Under these cijrcumstanc'es it becomesdesirable to equipfthe radio receiving instrument with devices designed for effecting micrometric adjustments. i V i o-called Vernier adjustment devices have heretofore been provided particularly in conjunction with variablecondensers. The most common of theseis the well-known Vernier condenser comprising two sets of rotatable plates mounted on concentric shafts and provided with concentric control knobs. One of the sets of rotatable plates usually consists of a single plate which is operable to effect fine capacity adjustments while the other i set is operable for coarse adjustments. Other arrangements have been proposed which do not involve separately rotatable elements for the fine adjustments. In so far as it has been possible to ascertain, .none of'these contenr plates the provision of an integral self-con tained device which is operable for effecting both coarse and fine adjustments. 4

The principal object of the present invention is to provide a simple and inexpensive device for effecting micrometric adjustments of ordinary variable electrical apparatus such as variable condensers, variometers, variocouplers and the like which can be connected In radio receiving"instruments provided The preferred embodimentfof the invention is. characterized by extreme simplicity and comprises two coaxial knobs one of which is" fixed to the'shaft and the other mounted thereon but free to'rotate independently thereof. Awvheel having prefer ably a rubber rim is" 'pivotally'attached to the fixed knob and disposed, in part at least. inside thereof. This wheel, which is appro priately referred to hereinafter as atraction. wheel,1sarranged'to frlctionally engage the panel and the free knob conjointly, 'thear-L rangement being such that rotation of the free knob may rotate the traction wheel which, by reason of its frictional engagement with the panel, revolves about the axis ofthe shaft and carries the fixed'kn ob with it, thus rotating the shaft." The .drivii'ig ratio between the free knob and the fixed knob is a predetermined factor and is, in general of such value that the free knob makes several revolutions for eachrevolution of the shaft. Thus it will be seen that very fine rotary adjustments of the shaft can be easily effected by rotating the free knob and coarse adjustments can be made by rotating the fixed knob. I

It is thought that a clearer understanding of the invention may be had from the following detailed description in conjunction with the accompanying drawing, in which i Fig. l isa cross sectionalview of a variable control device in accordance with the preferred embodiment of the invention;

Fig. 2 is a front elevation of the device; Fig. 3 is a rear elevation of the device; and Fig. 4 is a rear elevation of the fixed knob with the dial part thereof removed in order to show the traction wheel and its support more in detail.

i any variable electrical instrument suchas'a variable condenser, variometer or variocoupler, and 1s shown pro ecting through a f mounting panel 2, on which the instrument to be controlled may be mounted. A knob 33,

comprising two parts 3 and 3 is fixedly secured to the shaft by means of a set screw 4. The parts 3 and 3 are fastened together by three flat head machine screws 5. The

part3 is graduated as shown in Fig. 2, and

forms the usual dial for indicating the setting of the instrument.

loo

A metal bushing 6 is bored to receive shaft thereto by the flat head machine screw 12.

The free knobis-rotatable about the bushing (3 independently ofany: rotation of shaft l or knob 2h It will be noted that the screw 12.

does not clamp the free knob against the endol bushing 6 and that the function, oi. this screw is merely to prevent the free knob fall'- ing oil the bushing.

As is clearly shown in Fig. l, the free knob ll has a frusto-eonical portion 11 the surface of which is adapted to engage the the 10 of traction wheel 5). rotation of the tree knobll imparts a rotary movement to*the traction wheel causing it to revolve about the axis of sha ft 1 by reason of its t actional engagement with panel 2. Since the traction wheel is attached to knob 3, revolution of the former will cause the latter to rotate carrying with it the shaft 1. The

driving ratio between the free knob 11' and the fixed knob 3 is preferably such that severalrevolutions of the former are required to et tect one revolution of the latter.

According to the preferred arrangement When thus engagedas shown in Fig.1, thereis normally some clearance between either the freeknob and the traction wheel or between the traction wheel and the panel, so that it is neceeeary to press slightly on the free kuobin order to cause the tract-ion Wheel to effectively engage both the free knob and the panel. It is notnetessary, however, to provide this clearance.

In operation the instrument is adjusted to the approximate setting by direct rotation o'l the fixed knob 3, after which the fiiie adjustment'is obtained by turning the free knob 11, exceedingly tine rotary adjustments being thereby obtainable with no dilliculty.

It is realized that a great many modificationsand alternative arrangements are possible within the scope and'spirit of this invention, audit should not therefore be construed as limited except by the scope of the appended claim.

I claim:

A variable control device comprising an adjustingmember engageable with a shaft, a swinging pivot pin pivotally connected with said member at one end, aroller journalcd on the free end of said pivot pin andan adjusting knob 'journaled'on eaidmemberaiul engageable with the outer rim of said roller to therebyswing the pivot pin inward to of feet engagement of the inner rim of the roller with a stationary surface at the bucket" the adjusting member.

In testimony whereof L afllx my signature.

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