US2348392A - Variable condenser - Google Patents

Description

' May 9, 1944. s KESTER 2,348,392

VARIABLE CONDENSER Filed July 8. 1942 INVENTOR 5 flz-ZMni Z1 ester 8 BY flWJ ATTORN EY Patented May 9, 1944 VARIABLE CONDENSER Arthur S. Kester, Chicago, 111., assignor to The Rauland Corporation, Chicago, Ill., a corporation of Illinois Application July 8, 1942, Serial No. 450,169

2 Claims.

This invention relates to new and useful improvements in variable condensers.

The object of the present invention to effect certain improvements in the condenser structure disclosed in my copending application Serial No. 425,987, filed January 8, 1942.

I To carry out this object, means are provided to prevent the movement of the condenser plates, and thus the varying of the capacitance, except under the wishful control of the operator and for simplifying the mounting of the control or driving shaft.

A preferred embodiment of the invention will now be described with reference to the drawing in which Fig. 1 is a side elevation with parts broken away;

Fig. 2 is another side elevation partly in section;

Fig. 3 is a section taken along lines 3-3 of Fig. 1;

Fig. 4 is a perspective view of the disc for taking up the end thrust on the main shaft;

Fig. 5 is a side elevation of the support for one of the bearings of the driving shaft; and

Fig. 6 is a perspective, with parts broken away, of a bearing of the driving shaft.

The condenser consists of rotor plates l mounted on a long sleeve 2 and cooperating with stator plates 3 which are fastened by means of screws 4 between two opposite strips of insulation, one of which is shown at 5 in Fig. 1. One end of strip 5 is fastened by a screw 6 to a shoulder 1 (Figs. 1 and 3) of the main frame, which in the structure illustrated is a casting carrying the control elements. The other end of the strip 5 is fastened to an end plate (not shown). The other insulating strip which is not shown is fastened to a shoulder 8 (Fig. 3) of the main casting and the above mentioned end plate.

A similar stator rotor assembly is provided on the left-hand side of the main casting (Figs. 1 and 2).

The main casting has a front wall 9 and two spaced transverse wings It) and II. The front wall has a central window opening l2. The wings I!) and H have their corners cut-off to form said shoulders I and 8, The sleeve 2 surrounds and is fastened to the right-hand portion of a shaft is which traverses the whole length of the condenser through openings in the wings ill and II where it is seated in ball bearings like M (Fig. 2).

Between the wings I and II, the shaft l3 carries a gear l hub l6 of which is pinned to .carries also a semi-circular casting la provided with a number dial or scale and a quadrant i9 rotatably mounted on a hub (Fig. 3) of the casting IS, the latter being fastened to the shaft I: by a set screw. The edge of the quadrant l9 which is visible through the window i 2 has a reference line 2| (Fig. 2) cooperating with the scale on dial it. The position of quadrant l9 and, therefore, of the reference line 2| is determined by a set screw 22 against which I! is pulled by a coiled spring 23. The set screw projects through an ear 24 of a cross-piece 25 which is fastened to the wings II) and II of the main casting by screws 26. One end of spring 231s fastened to quadrant l9 and the other end to the cross-piece 25 below screw 22.

The shaft l3 and thus the rotors of the condenser and dial it may be rotated by turning a knob 21 fastened to one end of a transverse driv- 20 ing shaft 28. A dial 29 is integral with knob 28 and serves to indicate the angular displacement of the driving shaft which has a worm 30 engaging the teeth of gear [5 against which it is pulled by a coiled spring 3|. The teeth of the worm and gear being wedge-shaped, back-lash is prevented.

One end of spring 3! is attached to asquare bearing 32 on the end of shaft 28. The bearing 32 is held within two lateral guides 33 (Figs. 3

and 5). The guides are formed in a vertical arm 34 of the cross-piece 25 and they are closed at the bottom as shown at 35. The other end of spring 3| is wrapped around an adjusting screw 36 in thecross-piece 25. The bearing 32 is allowed a limited lateral movement between a shoulder 31 and a ring 38 on the shaft.

In order to guard against the rotation of the condenser by a downward thrust on the projecting end of the shaft or an upward thrust on the knob 21, a screw-threaded stop 39 is provided in the bottom 35 of the guide 33. If the stop 39 were not provided, then the bearing 32 would be free to move far enough to cause the rotation of the main shaft owing to the torque exerted by worm so on gear 15. The stop can be set for allowing up and down movement of the ends of shaft 28 to any desired extent.

The spring 3| will lift the back end of the shaft 28 so as to insure good contact between l5 and 30. The slight bodily displacements of the driving shaft are made possible by providing a ball shaped bearing surface 40 thereon, the worm 30 being intermediate the two bearings 40 and 32.

Theball 40 engages a cup-shaped seat 4| on a the shaft at H. This portion of the shaft i3 sleeve 22. The sleeve is anchored in position by two lugs 43 projecting in slots of a retaining plate 44. The plate 44 is fastened to a bushing 45 formed in the main casting and is spaced from plate 5| by a felt or rubber pad 52. The sleeve 42 houses a coiled spring 48 which presses seat I into contact with ball 40. The curvature of the seat 4| is such that no torque is apparent when the knob 21 is free.

The end thrust in the rotor shaft i3 is absorbed by a disc 48 (Figs. 2 and 4) on shaft i3 between sleeve 2 and wing II and which together with its supporting rigid washer I8 is fastened to the latter by screws 41. Spring fingers 48 stamped out of disc 46 bear against wing ll adjacent the outer race of the ball bearing II. A washer II is within the circle formed by spring fingers 48 and prevents the pressing of disc 48 towards bearing it to such an extent as to distort the spring fingers 48.

The main casting is mounted on a plate II which may be attached to a panel.

What I claim is:

1. In a drive for variable condensers and the like, a main shaft, a driving gear fastened to the shaft, a driving shaft having a worm intermediate its ends engaging said gear, a bearing for one end of said driving shaft, 9. guide confining one end of said bearing for movement in one plane, resilient means forcing said bearing in said plane in a direction to press the worm into engagement with the gear, a movable stop limiting the motion assesses c! said bearing in the opposite direction in said plane, a ball formed on the driving shaft between the worm and its other end, a cup shaped seat for said ball, and a knob fastened to said other end of the shaft for rotating it.

2. In a drive for variable condensers and the like, a frame having two spaced transverse wings, a main shaft projecting through the wings, a bearing for the shaft in each wing, a driving gear fastened to the shaft between the two Wings, a horizontal transverse shaft between the wings at right-angles to the main shaft and having a worm intermediate its ends engaging said gear, a bearing for one end of said transverse shaft, a guide having a bottom and side walls between which the bearing is mounted free to move vertically, a coiled spring attached to said bearing and tending to pull it up vertically and thus the worm into engagement with the gear, a screwthreaded stop projecting through the bottom of the guide into engagement with said bearing limiting its downward movement, a ball formed on the transverse shaft between the worm and its other end, a sleeve on said transverse shaft and having a cup-shaped seat for said ball and two positioning lugs, a coiled spring within said sleeve surrounding the shaft, and a retaining plate fastened to said frame having notches for said lugs and an opening for the passage of the transverse shaft.

ARTHUR S. m.

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