US1571370A - Variable condenser - Google Patents

Description

' Feb. 2 1926 1,571,370

(5. H. CLARK VARIABLE CONDENSER Filed March 5, 1921 g2 Ill 5 1s 12 10 2 2 z Patented Feb. 2, 1926.

UNITED STATES GEORGE HOWARD CLARK, 0F BROOKLYN, NEW YORK, ASSIGNOR TO RADIO CORPORA- TION OF AMERICA, A CORPORATION 015 DELAWARE.

VARIABLE CONDENSER.

Application filed March 3, 1921. Serial No. 449,393.

To all whom it may concern:

Be it known that I, GEORGE H. CLARK, a citizen of the'United States, and a resident of Brooklyn, New York, have invented certain new and useful Improvements in Variable Condensers, of which the following nailing, consists of two sets of flat semi-circular plates, one set being fixed and the other set rotatable between the fixed plates, so that segments of each set of varying area are placed in juxtaposition. With this type of condenser the. minimum capacity is arbitrarily calculated at 10 and the maximum at 170. The ratio of maximum to minimum for these values is about 17 to 1.

My invention aims to increase the ratio of maximum to minimum and the actual range of capacity with this type of condenser. However the invention is not necessarily limited thereto, although for convenience it will be described in this connection.

The novel features which I believe to be characteristic of my invention are particularly set forth in the appended claims, the

invention itself, however, both as to its construction and mode of operation, together with further objects and advantages thereof, will best be understood by reference to the following description taken in connection with the accompanying drawings, in which:

Fig. 1 is a section of a variable condenser embodying my invention and Fig. '2 is a section on the line A--A of Fig. 1.

The objects referred to are secured by providing a construction in which the distance between the plates, as well as the cooperating overlapping surfaces of the condenser is adapted to be varied to change the capacity. A desirable arrangement for accomplishing this result, as illustrated byway of example in the drawings, comprises-a casing 1 having a plurality of semi-circular metal plates 2 in the lower part spaced equidistant and electrically connected, for example by means of a rod 3, passing through lugs 4, which extend into thereof, which are the bottom of the casing. In the upper part of the casing a similar set of semi-circular plates 5, is located, the plates being fastened to the rotatable shaft 6 and spaced about the same distance as the plates of the first set. One end 7 of the shaft is screw threaded and adapted to fit in a cup shaped bushing 8 and the other end 9 is fitted in another bushing 10 and keyed to the stud 11 of a knob 12 made of insulating material. A stop 13 is provided to limit the sidewise movement of the plates when the shaft is rotated. The end of the casing is provided with a dial 14 and an indicator 15 cooperating therewith is attached to the shaft 6.

With the arrangement described it is pref erable to space the plates so that when the rotatable plates are turned into the upper most position as shown in Fig. 2, the planes of the plates of one set are intermediate and equidistant from the planes of the plates of the other set. In the type of condenser referred to previously, this relative position is maintained when the upper set of plates is rotated to vary the capacity. According to the invention as illustrated in the arrange ment shown, the spacing between the plates is changed as the overlapping is varied. The screw threaded rod and bushing, which is merely a convenient cam action for this purpose, draws the plates toward the right during the rotation. so that when the plates are rotated through 180, the' end of the shaft abuts against the bottom of the cup shaped bushing. This brings the planes of one set of plates gradually closer to the planes of the other set of plates.

With a plurality of plates in each set this, of course, draws the plates nearer to one cooperating plate and further from the other, which increases the capacity between. the close plates and decreases the capacity between the distant plates as compared with equidistant plates. However, it can be shown that an increase of capacity is secured in this manner, as the proportional in crease is greater than the decrease referred to v I have found when my invention is applied to a condenser of the type having a set of rotatable semi-circular plates and a set of stationary plates, ordinarily having a maximum to minimum ratio of 17 to 1, that this can readily be increased to 30 to 1 by means of my invention. With plates .03"

Bill

apart this result can be secured by moving the rotatable plates so that they are .01" from the close fixed plates. The actual capacity and the range is thus increased substantially 75%. This increased capacity will also permit the use of a condenser .hav-

ing smaller or less plates .for the same purpose, and will give a better ratio. of maximum to minimum.

Having described my invention what I claim is 1. A variable electrical condenser, comprising spaced juxtaposed fiat and parallel surfaces adjustable as to the area of the surfaces in juxtaposition and as tothe dis- .tance between the surfaces by manipulation prising a pair of spaced fiat and substanlially parallel condenser plates, one of said plates being fixed and the other mounted on a shaft and slidably and rotatably adjustable relative to the fixed plate, and means for varying the distance between said plates by manipulation of said shaft.

4. A variable electrical condenser comprising a pair of spaced-flat and substanti'ally parallel condenser plates, one of said plates beingfixed and the other mounted on a shaft and rotatable to vary the overlapping surfaces, and means for varying the distance between said plates by manipulation of said shaft. 4

4 5. A variable electrical condenser comprising' a pair of spaced flat and substantially parallel condenser plates, one of said plates being fixed, mleans for rotating the other plate about an axis to vary the overlapping surfaces and means cooperating with the rotating means for simultaneously" varying the distance between said plates.

6. A variable electrical condenser comprising a set of spaced flat condenser plates,

a second set of spaced fiat condenser plates amounted on a shaft to be slidably and rotatably adjustable between the first set and means for varying the effective separation .of the plates by manipulation of said shaft.

7. A variable electrical condenser comprising a set of fixed equidistant flat condenser plates, a second set of equidistant flat condenser plates mounted on a shaft and slidably and rotatably adjustable between the plates of the first set and means for moving one set of plates laterally by manipulation of said shaft to vary the effective spacing of the plates of the condenser.

8. A variable electrical condenser, comprising a set of fixed condenser plates, a set of semi-circular plates, rotatable between the plates of the first set, means for rotating said plates, means for longitudinally moving the axis of rotation of the second set by manipulation of said first named means to vary the effective se aration of the plates.

9. A. variab e electrical condenser comprising a set of fixedcondenser plates, a shaft having a second set of condenser plates attached thereto, and movable between the plates of the first set, said shaft being rotatable to vary the oi'erlapping surfaces, and means cooperating with said shaft for moving one of the sets longitudinally in relation to the other set by manipulation of said shaft.

10. A variable electrical condenser comprising a set of fixed condenser plates, a shaft having a second set of condenser plates attached thereto and movable between the plates of the first set, said shaft being r0- tatable to vary the overlapping surfaces, 8. support for said shaft and means cooperating with said support for mloving the shaft longitudinally during said rotation.

1.1. A Variable electrical condenser comprising a set of. fixed condenser plates, a

shaft having a sepond set of condenser plates attached thereto and adapted to rotate the attached plates between the fixed plates and a support for said shaft, said shaft and support being threaded to produce longitudinal movement of the shaft during its rotation.

GEORGE HOWARD CLARK.

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