US2913646A

US2913646A - Electric condensers

Info

Publication number: US2913646A
Application number: US564170A
Authority: US
Inventors: Jr Atherton Noyes
Original assignee: AIRCRAFT RADIO CORP
Current assignee: AIRCRAFT RADIO CORP
Priority date: 1956-02-08
Filing date: 1956-02-08
Publication date: 1959-11-17
Anticipated expiration: 1976-11-17

Description

NV17,1959 y A.NoYEs,JR 2,913,646

' ELECTRIC coNDENsERs Filed Feb. 8. 1956 2 Sheets-Sheet l ,co7 INVENTOR.

Nov. 17, 1959 A. NoYEs, JR 2,913,646

ELECTRIC CONDENSERS United States Patent O ELECTRIC CONDENSERS Atherton Noyes, Jr., Mountain Lakes, NJ., assignor, by mesue assignments, to Aircraft Radio Corporation, a corporation of New Jersey (1958) Application February 8, 1956, Serial No. 564,170

6 Claims. (Cl. 317-254) This invention relates to electric condensers and aims to provide a variable electric condenser whose capacity is accurately predetermined and made insensitive to temperature variations.

It has been found that even though the thermal expansion of the shaft and the frame of a condenser are equal, objectional changes in the capacity will occur under the iniluence of thermal expansions and contractions of the condenser parts, unless the tixed plates are located accurately parallel to, and exactly centered between, the rotary plates. The object of the present invention is to provide for an initial adjustment of the fixed plates which shall comply with these two desiderata.

In accordance with the invention, the xed plates are mounted in groups between transverse partitions or septums of the condenser frame for micrometric translational and turning adjustment. An important feature of the invention consists in making such adjustments in relation to a point and a plane which are xed in relation to the planes of the movable plates.

The invention will be described in connection with a condenserembodying it and shown in the accompanying drawings in which Fig. 1 is a plan view of the condenser;

Fig, 2 is a transverse section on the line 2-2 of Fig. l;

Fig. 3 is a transverse section on the line 3-3 of Fig. l;

Fig. 4 is an enlarged longitudinal section of a part of the condenser on the line 4-4 of Fig. 5;

Pig. 5 is an enlarged plan view of the part of the condenser between two transverse partitions or septums,v

showing parts in section;

Fig. 6 is a detail sectioned on the line 6--6 of Fig. 5; and

Fig. 7 is a fragmentary section on the line 7-7 of Fig. 5.

The condenser illustrated has a frame 10 provided with transverse septums 11. In the frame is mounted a rotary shaft 12 to which the rotary plates 13 of the condenser are secured. End shake of the shaft 12 is prevented in the usual manner by a spring 15.

The iixed plates are mounted in groups between the septums 11. Each group of xed plates is provided at opposite sides with supporting rods 21 of micrometrically adjustable length.

Each supporting rod 21 consists of a hollow or tubular portion 22 containing evenly spaced external grooves 23 in which the plates 20 are secured by soldering. Each rod 22 has a bore which is of different diameters in two end portions of the rod. The smaller portion of the bore 24 is internally threaded. An adjusting screw 25 engages the threads 24 and has an enlarged cylindrical head 26 which fits in the larger portion 27 of the bore in the rod 22. An opening 28 in the rod 22 provides access to sockets 29 in the head 26 of the screw for the insertion of an adjusting tool.

The head 26 of the screw 25 has at its outer end a circular socket 30 for the reception of a ball 31 of glass or other hard insulating material. A similar socket 2,913,646 Patented Nov. 17, 1959 32 is provided at the end of the rod 22 which contains the threaded bore.

The stator consisting of the fixed plates 20 and the adjustable supporting rods 21 is mounted between two septurns 11 of the frame. Sockets or

bearings

35, 36 for the balls 31 at one end of the stator are provided in one of the septums 11, while sockets or

bearings

37, 38 for the balls at the-other end of the stator are provided in a leaf spring 39 pivotably mounted on a stud 40 on the next septum 11. The socket 35 is circular and holds the ball which is in engagement with it in a fixed position with respect to the frame 10. The socket 36 is a straight slot having its axis directed towards the center of the socket 35. The

sockets

37 and 38 are also straight slots and they have their axes on a diametrical line of the spring 39, that is, on a line passing through the axis of the pivot stud 40. The form and arrangement of the sockets serve to make the stator adjustable in a xed plane and about a fixed point in this plane. The fixed plane is defined by the centers of the

sockets

35 and 36 and the center of the stud 40. The xed point is the center of the circular socket 35. Both the plane and the point are fixed with respect to the frame 10 and, therefore, in respect to the planes of the movable plates 13.

To avoid any play in the bearing of the spring 39 on the stud 40, the hole for the stud is formed in a slot 41 and a parallel slot 42 is formed in the spring 39 in one side ofthe slot 41. Prior to heat-treating of the spring, a tool inserted in the slot 42 is used to deform the portion of the spring between `the slots inward toward the stud hole, thus insuring that when mounted on the st ud the spring will be free of translational play, yet still free to rotate to conform to the required reference plane.

The stator is adjusted by turning the screws 25 by means of an instrument inserted in the holes 29. Translational adjustment is obtained by turning both screws the same amount in the same direction. Rotational adjustment is obtained by turning one of the screws with respect to the other.

The two adjustments are made after the condenser has been completely assembled so that the correctness of each adjustment may be determined by electrical measurement. Each adjustment is made in such a way as to obtain minimum capacity for the section of the condenser being adjusted. This insures positioning the fixed plates accurately parallel to the movable plates and placing them in the middle of the spaces between pairs of the movable plates.

After this adjustment has been accurately made, a change in the temperature of the condenser has a minimum effect on the capacity of the condenser. Furthermore, wherever the balls may be seated in the slots, good mechanical stability is maintained regardless of minor inaccuracies in the manufacture of the parts.

What I claim is:

1. In an electrical condenser, the combination with two septums of a supporting frame, of an adjustable stator comprising a series of plates, two hollow supporting rods attached to said series of plates at opposite sides thereof, a part of each rod being internally threaded, a screw threaded into the threaded part of each supporting rod, each rod and each screw having at its outer end a circular socket, a ball of insulating material engaging the socket at each end of each rod, a circular socket in one of the septums for the ball at one end of one of the rods, a socket in said septum for the ball at the corresponding end of the other rod having the form of a straight slot directed toward said circular socket, a leaf spring pivotably mounted on the other septum, and radial slots in said spring for receiving the balls at the other ends of the two rods.

2. In an electrical condenser, the combination with two septums of a supporting frame, of an adjustable stator comprising a series of plates, two hollow sup- POIIIlg IOdS attached to said series of plates at oppositeV sides thereof, a part of each rod being internally threaded, a screw threaded into the threaded part of each supportingl rod, each rod and each screw having at its outer end a circular socket, a ball of'insulating material engaging the socket at each end of each rod, a circular socket in one of the septums for the ball at the screw end of one of the rods, a socket in said septum for the ball at the screw end of vthe other rod having the form of a straight slot directed toward said circular socket, a leaf spring pivotably mounted on the other septum, and radial slots in said spring for receiving the balls at the other ends of the two rods.

3. In an electrical condenser having a frame with transverse septums and having movable plates mounted on a shaft extending through said frame, an adjustable stator unit between two ofV theV septums of the frame comprising a setvof plates, two supporting rod assemblies secured to opposite sides of the set of plates, each assembly having fixed means providing a xed bearing surface at one end thereof and adjustable means providing an axially adjustable bearing surface at the other end thereof, a xed pointA bearing in one of the septums supporting the adjustable means of one assembly in engagement with the bearing surface thereof, straight elongated slotV bearings with the greater length thereof directed substantially in a common planepassing through the longitudinal axis of both said assemblies for supporting respectively the fixed means and other adjustable means in engagement with the bearing surfaces thereof, and resilient means cooperating therewith for urging the bearings associated with the fixed means towards the bearings'at the opposite ends of the assemblies.

4. In an electrical condenser, the combination with two septums of a supporting frame, ofan adjustable stator comprising a series of plates, two supporting rod assemblies secured to opposite sides of said series ofV plates, each assembly having fixed means providing a'iixed bearingsurface atone end thereof and adjustable means providing an axially adjustable bearing surface at the other end thereof, a iixed point bearing in one of the septums supporting the adjustable means of one assembly in engagement with the bearing surface thereof, a bearing in said one septum for supporting the adjustable means of the other assembly in engagement with the bearing surface thereof and consisting of a straight slot'directed towards said point bearing, aleaf spring pivotally mounted on the other septum, and bearings in saidspring for sup porting respectively the xed means in engagement with the bearing surfaces thereof, each of the bearings in the spring comprising a straight slot directed towards the pivotal axis of the spring'.

5. In an electrical condenser, the combination with two septums of a supporting frame, of an adjustable stator unit comprising a set of plates, two supporting rods secured to opposite sides of said set of plates, each of said rods having balls of insulating material disposed at opposite ends thereof and means cooperating therewith for axially adjusting one of the balls while the other ball remains fixed relative to the rod, a circular socket in one of the septums for the axially adjustable ball associated with one of the rods, a socket in said one septum for the axially adjustable ball associated with the other rod having the form of a straight slot directed toward said circular socket, a leaf spring pivotally mounted on the other septum, and radialV slots in said spring for receiving respectively a different one of the fixed balls associated with the two rods.

6. In an electrical condenser having a frame with transverse septums and having movable plates mounted on a shaft extending through said frame, an adjustable stator unit between two of the septums of the frame comprising a set of'platestwo supporting rodassemblies secured to Opposite sides ofthe set of plates, each assembly, having fixed means providing a iixed bearing surface at one end thereof and adjustable means providing an axially adjustable bearing surface at the other end thereof, a fixed point bearing in one of the septums supporting the adjustable means of one assembly in engagement with the bearing surface thereof, a straight slot bearing in said one septum directed toward said point bearing for supporting the adjustable means of the other assembly in engagement with the bearing surface thereof, a leaf spring mounted on the other septum, and'straight slot bearings in said spring directed towards each other for supporting respectively the fixed means in engagement with the bearing surfaces thereof, said spring urging said assemblies toward the bearings in said one septum.

References Cited in the iile of this patent UNITED STATES, PATENTS 1,579,482 Jorgensen Apr. 6, 1926 1,756,447 Behringer Apr; 29, 1930 2,077,544 Behr Apr. 20, 1937 2,282,215 Drake May'S, 1942 FOREIGN PATENTS 701,991 Great Britain Ian. 6, 1954l