US1958424A - Variable air condenser - Google Patents

Description

May 15, 1934. L. A. GEBHARD VARIABLE AIR coNDENsER Filed Dec. 24 1950 2 Sheets-Sheet l mw, w ma W ma? w WA w -MY MB w May 15, 1934. L. A. GEBHARD VRIABLE AIR CONDENSER Filed Dec. 24, 1930 2 Sheets-Sheet 2 1 IIIIIIIIIIJ`VIII'IIIIl/I W O f f z 3 z W w z 7 8 .w a W w ,a z JF: AW O ma w Q w AM O r z (WI O Z k f fa f ,7M fa ATTORNEY Patented May 15, 1934 UNITED STATES I 1,958,4z4 PATENT OFFICE Claims.

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 O. G. 757) My invention relates broadly to high frequency signaling systems and more particularly to an improved construction of variable air condenser for high frequency signaling systems.

In a high frequency transmitter covering a wide frequency band, it is desirable to have the frequency controlled by variable condensers which have a large ratio of minimum to maximum capacity. This condition is required in order that the widest possible frequency band may be covered. In high power circuits the push-pull tube arrangement is generally used. This requires symmetry of all parts of the circuit and therefore of the variable condensers used. It is also desirable where the condenser is used in circuits of very high frequency to have the capacity between high potential points of the condenser and ground of minimum value. It is desirable, therefore, to arrange the condenser so that the controls, etc., which have fairly large capacity will be at substantially ground potential.

My invention has for its object the construction of a high frequency condenser for transmitters utilizing a push-pull power amplifier system by which symmetry may be maintained throughout the adjustment of the condenser over a wide frequency band where the condenser has a large ratio of maximum to minimum capacity.

Another object of my invention is to provide means for supporting a multiplicity of fixed plates in a symmetrical condenser system with respect to a set of adjustable plates with a single 85 control for adjusting the capacity of different portions of the condenser system simultaneously, the arrangement of plates being such that a minimum capacity exists between lthe points of high potential in the condenser and the ground.

Other and further objects of my invention reside in the construction of a symmetrical condenser system as set forth more fully in the specification hereinafter following by reference to the accompanying drawings, wherein:

Figure 1 is a side elevation of the condenser system of my invention; Fig. 2 is a cross-sectional view through the condenser on line 2--2 of Fig. 1; Fig. 3 is a Vertical sectional view of the condenser on line 3-3 of Fig. 1; and Fig. 4 is a Vertical sectional view through the condenser on line 4-4 of Fig. 1.

The high potential plates of the condenser are arranged in two banks 1 and 2 with plates in the respective banks set edge to edge and parallel. Into the space between these stationary plates the movable group plates 3 are introduced. Groups 1 and 2 are supported by means of spacers 4 from insulating member 5. Movable group of plates 3 is supported from threaded rods 6 and 7 by means of screw threaded members 8.

Screw threaded members 8 are attached to spacers 9 which serve to hold the plates of the group 3 apart. Threaded rods 6 and 7 are supported in bearings 10 and 11 which are in turn mounted on insulating member 5. The upper ends of the threaded rods 6 and 7 are supported in bearings 12 and 13 which are in turn supported from insulating member 14. Bevel gears 15 and 16 provide simultaneous control by crank 17 through fiexible couplings 18 and 18a of the two threaded rods 6 and 7. Bevel gears 19 and counter 20 which is visible from the front panel 21 of the transmitter permit resetting the condenser to any particular point. Insulating members 5 and 14 are held together by means of supports 22 so as to form a rigid frame work for the condenser which is supported from the frame work of the set as shown at 23.

The sets of high potential plates 1 and 2 are illustrated as three in number in the arrangement shown in the drawings, however, additional plates may be employed. The spacer members 4 serve to maintain the plates in a Vertical plane. The sets of stationary plates 1 and 2 have the individual plate members thereof electrically interconnected by the rod or bolt members 25 which pass through the spacer members 4 and are bonded to the plates. The members 4 are rigidlyv secured to the laterally extending insulating frame member 5 by screw members 4a. The central plate (or plates) is bonded to the interconnecting members 25 forming an extension of the capacity areas established by the outer plates of the sets of plates 1 and 2.

The spacers 9 which maintain the spacial relat-ion of the adjustable plates 3 have bolt meinbers 26 extending therethrough which, with the spacers 9, serve to electrically bond and mechanically embrace the adjustable plates as a unitv The screw threaded lugs 8 which are engaged by the screws 6 and 7 are rigidly connected to the spacer members 9 by screw members 27 which pass into the spacers. The movable plates 3 are adjusted vertically with respect to the sets of stationary plates 1 and 2 to a position which is symmetrical with respect to each portion of the amplifier circuit with which the high potential condenser is designed to cooperate. The control and parts connected thereto which have a fairly large capacity, are substantially at ground potential. A large ratio of maximum to minimum capacity is obtainable by reason of the wide Variation in the spacing relation of the condenser plates which it is possible to obtain.

While I have described the high potential condenser of my invention in certain preferred embodiments, I desire that it be understood that modifications may be made and that no limitations upon my invention are intended other than are imposed by the scope of the appended claims.

The invention herein described may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. A variable air condenser comprising an insulated frame structure, independent sets of condenser plates erected in Vertical 'planes upon said insulated frame structure, a pair of rotatable screws disposed on opposite sides of said vertically disposed condenser plates, a set of ad- V;ustable plates, a pair of members respectively engagng said rotatable screws and respectively attached to each of said adjustable plates at points thereof substantially spaced apart, and means for selecting the position of said adjustable plates with respect to said sets of condenser plates.

2. A variable air condenser comprising a laterally extending insulated frame structure, duplicatesets of condenser plates disposed in Vertical planes, means extending from said insulating frame structure andsecured to the lower extremitiesof saidy condenser plates for erecting and maintaining said plates in Vertical planes, a pair of rotatable screws disposed adjlacent the remote edges of each of said sets of plates, a set of adjustable plates, means including a plurality of threaded lugs supportingly attached to said adjustable plates for adjustment thereof in cooperation with said screws and means for actuating said screws, for shifting the position of said `adjustable plates with respect to said first mentioned sets of condenser plates for changing Vthe electrical capacity. with respect to said duplicate sets of lcondenser plates in equal amounts.

3. Ina'variable air condenser, a frame structure comprising a pair of laterally extending frame members of insulating material, a pair of rotatable screwithreaded shafts extending vertically between said llaterally extending frame members,independent sets of condenser plates erected vertically Aupon one of said frame members and disposed between said rotatable shafts, a set o f adjustable plates, screw threaded members connected with the endsV of said adjustable .plates at points thereof spaced substantially apart and engaging said rotatable screw threaded members, :and means for rotatably driving said screw threaded shaft members for variably interleaving said adjustable plates with said independent sets of Vvertically' erected plates.

` 4. In a variable air condenser, Va Vframe structure comprising a'pair of insulation members, a pairof screw threaded Vrotatable shafts extending between Vand journalled with respect to said pair of insulation members, a plurality of threaded lugs engaging said rotatable screw threaded shafts, -a set of adjustable condenser plates,

mounted on said threaded lugs independent sets' Vof fixed condenser plates supported by one of said of condenser plates, a set of adjustablecondenser plates extending between said shaft members,

screw threaded members attached -to each of said adjustable condenser plates at, at least, two spaced pointson opposite edges thereof and engaging said rotatable shaft members for maintaining said set of adjustable plates in a balanced 'adjustable condenser plates at points substantially spacedV apart and engaging the screw threads on said rotatable shafts, and means for imparting equal rotatable movements Vto saidv shafts for shifting the position of said set of adjustable plates rectilinearly and in proportionate relation to Veach said independent set of condenser plates.

77. A'Variableair condenser comprisng incom-iV bination, a frame structure, a plurality of independent sets of stator plates, the sets being 'insulated from one another and from said frame structure .by which they are supported, a set of adjustable plates adapted Vto be interleaved'with said stator plates, and means including a plurality of screw driven lugs attached to said adjustable plates for Vadjustably positioning the same whereby the capacitative relation ofv said adjustable plates to each set of stator plates is proportionately varied. i

8. A device in accordance with'claim 7, in

which said adjustable plates are movable in a' rectilinear direction and corresponding'plates of the stator sets are arranged to be inteleaved by' each single adjustableplate.

9. In a variable air condenser, a frame structure comprising laterally etending insulation members, a plurality of sets of stator plate members supported by one of said insulation`members,

means electrically andimechanically bonding together the stator plate members of each said set as an independent capacity unit, a set of adjustable plates electrostatically common to the several sets of stator plate members, 'and means for shifting the position-of said adjustable platesV rectilinearly in respect to said stator plate'members for varying the capacity relation to each set` thereof proportionately.

' 10. In a variable air condenser, a frame structure comprising laterally extendingl insulation members and transversely extending platesupporting members, independent sets of stator plates held by said transversely extending members, the plates of each set being electrically bonded together thereby, a pair of rotatable screw 'i threaded shafts carried by said laterally extending insulation members, a plurality of screw threaded lugs engaging said shafts, and a set of adjustable condenser plates supported by said screw threaded lugs and adapted to be variably interleaved With said independent sets of stator plate members, the adjustn'ient thereof lbein provided by rotative movement of said Vscrew

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