US1712097A - Variable condenser - Google Patents

Description

May 7, 1929 H. R. VAN DEvl-:NTR

VARIABLE CONDENSER Filed April 25, 1925 .Patented May i", 19,25%a

UNITED STATES EARRY R. VAN DEVENTER, Gli' NEVI YORK, N'. Y., SSG-TE DUBLIER illfi c CORRATION, YORK, N. Y., A CORGRATON F DELAWARE..

VARIABLE CONDENSER.

Application filed .April 23,

clensers.

An object of my invention is to provide a 5 condenser in which the adjustment of the relative positions of the condenser elements is accomplished with the minimum of friction oi the parts.

Another object of my invention is to inake a condenser structure in which the condenser elements are resiliently held in close contact -for that portion of their surfaces that are in operative relationship to each other, at any given setting ot tnecontienser,

A further object of my invention is to provitle :i condenser so constructed that the means for effecting-' the acl'iistinents can he located on either sicle of the housing. thus making the contlenser adapted to a, Wide variety ot uses..

.fi still {nrt-her object ot my invention is to show how to construct a variable condenser that is sturdy, and capable of use by unskilled persons for long periods ot time Without the necessity of repair or replacement.,

Figure l is a view in longitudinal section oi niy flevice taken on a plane passing through the axis of the rotor shaft;

l 2 is a bottoni plan View o'liny Tvariable condenser with part of the cover plate broken away to more clearly show the posit-ion et the parte; l

Fig. 3 is a view in cross section oi my device taken on the line 3 3 of Fig. fi, looking in the direction oi the arrows;

Fig. 4; is a detail View in perspective of the retaining spring;

Fig. 5 is a detail view in perspective of the rotor;

Fig. 6 is a View in sicle elevation of iny variable condenser with a portion oi the casingV hrolen away., showing the adaptation of the condenser wherein an extension sha ft is inounteii on the cover plate sitle;

Figi. 7 a detail View in perspective of the :nljustahle element. of my condenser.

I have illustrated my invention as coinprisingf a casing l of sonic suitable insulating material sncli as hard rubber or Aiakeiite.

Wall of the housing for the va iiahle condenser. The casing; l has an upwardly extending cylindrical portion 3 Within which is journalecl 'conducting foil i4 and is preferably 1923. Serial No. 634,097.

a metallic shaft 4. The metailic s formed with apertures at either end As shown in the drawings, eperti entends the entire distance thronkvli th ter of the shaft and is screw-tliieitleil. lonfer end of the aperture 5 is slightlv ened, as inicated et t?, thereby ini conical seat 7. i

Formeel on the'shait 4, nrei. tegrelly made therewith, is e shov xvhich have shown as et Square conti tion, over which is adapted to tit an ti 9 centrally formed in e rotor l1 et insuiw material. The rotor ll is provifieci fvi'tii e slot l2 therein which is set en an i e raclii of the rotor. The slot, l2 isini with beveledr edges i3. The iit ioetif aperture 9 and; 'the shoulder 8 oi" the sh is not a 'tight it, l3nt the rotor is ada tient on the shoulder 8 and he cii ready movement in the direction of in of the shaft 4r.

Mounted against the upper' inte oi the casing l is an annular tixeal con plate lll preferably formed o metall-.c i. The condenser plete le tits into e recess orrnecl in the casing, and a metallic eye i6 is atiepted to pass through the sheet or plate of; nietaliic toil li and to maire f through @holding contat. p cw L.. i c cyelet lo is iiveteoi in @lace to ene connection permanent. 'doveiing` conducting sheet Llis an insulatingr sheet o inica 18 which is in close reletionsiiin te 'ined of thereto by a suitable adhesive.

The flexible condenser element comprises a iriexilile strip ot nieta-l. 19 of annular con-1 formation, see Fig. 7. This metallic strip has a. convolute intension ivliicli tends to spring,y e it out, as shown in Fig. 'i'. l@ne edge of the free enti et the lexilile eleii'ient iii is in tiu'iie, as intlicated at QG. The liexilile eleinent 19 is provided with a relativeiy witie neel: 2l exteneine' into an aperture 22 iorineti in the casing l. An eyelct 23 ina-lies 'contact with the flexible element i9 through s. holding contact member Q4. The eyelet- 23 is riv eted in place ancl makes permanent electrical connection. with the iexible sheet The free enel of the i'iexiale element is adapted to slide through the slot 12 in the rotor 1l. The rotor l1 is spring pressei in the direction oit the fixed element of t e c the mica sheet 18. The rotor 11 compresses that portion of the contacting surfaces of the fixed `and adjustable, elements which are adapted to be operative for any given capacity adjustment. In order to maintain the rotor 11 in this spring pressed relationship to the condenser elements, I have provided a spring member 25 having spring arms 26 which are upwardly intensioned, as indicated in Fig. 4. The spring member 25 is mounted over 'a downwardly projecting annular .flange 27 of the shaft 4. A washer 28 is fitted over the flange, and the flange 27 is then riveted to hold the spring member 25 firmly between the washer and the shoulder 8 of the shaft 4. This construction holds the spring member 25 firmly in place and permits the upper ends of the spring arms 2G to contact against the rotor 11 to urge it upwardly. The arms 26 are of such a length that the pressure is exerted on the rotor 11 at a point between the center of the .rotor and its circumference, thereby insuring that the maximum degree of pressure shall be exerted on the annular fixed and flexible condenser elements. If pressure were exerted at the cen* ter or periphery of the rotor, its effect would not be so readily transmitted as is the case where it is exerted directly adjacent to the main surface area of the condenser elements.

A turning knob 31 is attached to the shaft 4 by means of a screw 32 fitting into the screw-threaded aperture 5 of the shaft, whereby the shaft maybe rotated. A pointer 33 is keyed to the turning knob 31, and a shim washer 34 is mounted on the upper face of the upwardly projecting portion 3 of the casing 1. The shim washer 34 is depressed, as indicated at 35, into a depression formed in the portion 3 of the casing. Thereby the shim washer 34 is prevented from rotation, yet the knob and pointer 33 can easily turn. A shim washer 37 is provided on the interior face of the casing 1. The shim washer 3 is depressed, as indicated at 38, into a depression 39 formed in the upper interior wall of thecasing 1. These two shim washers have been found to add greatly to the sturdiness of the construction and the strength of the .general shaft assembly, preventing undue play after long use.

Fitting over the lower surface of the casing is -an insulating cover plate 40, held to the casing 1 by means of drive screws 41. An aperture 42 is provided in the. cover plate opposite the shaft 4, and apertures 43 are formed opposite the eyelets 1G and 23. The cover plate 40 forms with the rotor 11 a recess within which the flexible member 19 may be housed when it-has passed through the slot 12 of the rotor 11.

In operation, by turning the knob 31 in a clockwise direction, the rotor 11 is caused to move to pick up a portion of the flexible element 19 to vary the capacity of the condenser.

By reason of the bevelling of the edges 13, the picking up of the flexible element 19 is greatly facilitated, because the friction between the flexible velement and the rotor is reduced to a minimum by reason of the sharp entering angle presented to the surfaces. To increase the facility with which the rotor picks up the flexible element 19, the slot 12 is set at an angle to the radii of the rotor 11. This tends to make the outer edge of the rotor 11 have a slightly greater initial engagement with the flexible element 19, and this edge therefore operates as a starting wedge, thus further facilitating the picking up of the flexible element 19. Moreover, one edge 20 of the flexible element 19 is upturned, which aids the rotor 11 in picking up the elements, and by reason of the fact that the flexible element is given a convolute infcnsion in its manufacture and retains this convolute intension in the assembled device, the flexible element 19 has a tendency to spring out through the slot 12 in the rotor.

By rot-ating the rotor, the flexible plate 19 is subjected to a picking up and laying down operation on the fixed element whereby the capacity of the condenser is Varied. The casing 1 is provided with a scale which co-opera'tes with the pointer 33 to indicate the adjustment effected.

The utility of the apertured shaft 4 will be apparent from an inspection of Fig. 6, in which the condenser is shown mounted on the interior of a box 51. An extension shaft 52 is screw-threaded, through the aperture 42 in the cover plate 40, into the screw-threaded aperture 5 in the sha ft 4. The extension shaft 52 is provided with a conical seat 53 which engages the conical seat 7 formed in the shaft 4. A knob 54 is screwed by means of a screw 55 into the 'shaft 52, and a suitable scale may be provided for co-operation with the knob to indicate the adjustment of the condenser. Binding posts 56 are provided with extension screws 57 which pass through the eyelets 16 and 23 and through the apertures 43 in the cover plate 40. It is thus apparent that the utility of the condenser is largely increased by the construction which permits it to be used in the reverse position if desired.

lVhile I have shown and described the preferred embodiment of nl v invention` I wish it to be understood that I do not confine myself to the. precise details of construction herein set forth, by way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled in the art, without departing from the spirit of the invention, or exceeding the scope of the appended claims.

I claim: I

1. A variable condenser comprising. a fixed element, an adjustable element. a shaft, a rotor flotatably mounted on and adapted to turn with the shaft, a shoulder on the shaft, a washer on the shaft, a plurality of retaining springs for exerting pressure on the rotor mounted between the Washer and the shoulder, and means for holding the retaining spring between the Washer and the shoulder.

2. A variable condenser Comprising, a easing, relatively adjustable condenser elements within the casing, a shaft having a screwthreaded aperture therein at either end, a Cover plate for the easing having an aperture communicating with the shaft, and ine-ans adapted to engage With the serew-threads of the lapertureswhereby the condenser may be adjusted fot` compression from either side.

3; A variable condenser comprising, a casing, a lixed element, an adjustable element, a rotor having a slot therein through which the adjustable element is adapted to slide, a shaft upon which the rotor is mounted, means attached to the shaft for resiliently pressing the rotor against the ixed element, a knob to rotate the shaft, a pointer moving with the knob,

a shim Washer on the easing held against rotation by an indented portion litting into a depression in the easing, and another shim Washer on the interior of the easing and held against .rotation by an indented portion litting into a depression in the easing.

d. A variable condenser' comprising, a oasing, a fixed element, an adjustable element, a rotor having a slot therein through which the adjustable element is adapted to slide, a shaft upon which the rotor is mount-ed, means attached to the shaft for resiliently pressing the rotor against the fixed element, means eX- terior of the casing to rotate the shaft, a shim washer on the casing held against rotation by an indented portion fitting into a depression in the casing, and another shim Washer on the interior of the easing and held against rotation by an indented portion fitting into a depression in the casing.

In testimony whereof I affix my signature.

HARRY R. VAN DEVENTER.

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