US1543326A - Condenser and clamp therefor - Google Patents

Description

June 23, 1925. 1,543,326

w. DUBILIER CONDENSER AND CLA M? THEREFOR Filed Feb. 7, 1921 Patented June 23, 1925.

UNITED STATES 1,543,326 PATENT OFFICE.

WILLIAM DUBILIER, OF NEW YORK, N. Y., ASSIGNOR TO DUBILIER CONDENSER & RADIO CORPORATION, A CORPORATION OF DELAWARE.

commnsnn Am) CLAMP THEREFQR.

Application filed February 7, 1921. Serial No. 442,945. I

To (all whom it may concern:

Be it known that I, WILLIAM DUBILIER, a citizen of the United States, residing-at New York, in the county of New York and State of New York, have invented a certain newand useful Condenser and Clam Therefor, ofwhich the following is a speci cation.

The invention has for an object to provide a condenser having a clamp which, while affording the necessary degree of pressure upon the condenser stack, will yet involve 'but a small number of parts of simple con.-

struction, light weight and small size, and which may be readily assembled, thus mak ing the condenser particularly adapted for use where small units are desired. It is to be understood, however, that -the'invention is not limited in utility to condensers of small size.

Another object of the invention is to form a condenser clamp which will not tend to bow or warp over the active area of the condenser when the compression is applied to the latter, or in use of the condenser,-

for example, when expansion or contraction occurs due to temperature changes.

Another object of the invention is to provide a clamping device for condensers which may be adjusted to exert the necessary pressure upon the stack merely b pressing or forcing certain parts of sai device into operative position.

Further objects and advantages of the invention will be in part obvious and in part specifically mentioned in the description hereinafter contained, which, taken in connection with the accompanying drawings, discloses a preferred embodiment of the 1nvention; such embodiment, however, is to be considered merely as illustrative of its princi le.

In t e drawings- Figure 1 is a perspective view of a condenser and clamp made according to the invention;

Fig. 2 is a plan view of the structure shown in Fig. 1, certain of the parts being cut away;

Fig. 3 is a side view of one of the compresslon-appiying members shown detached. The invention is disclosed in connection with a condenser stack consisting generally of the dielectric sheets 1,-for example, of mica,-isterleaved with suitable groups of conducting sheets 2 and-3, respectively, the

dielectric sheets overlapping the conducting sheets on three sides, but each group of conducting'sheets projecting beyond'the stack (in the fourth side to form terminals 4 and 5. The condenser stack is preferably impregnated and then subjected to high pressure in the process of manufacture in such mancondensers of very small size which, however, should still be of as high efliciency as possible and. substantially constant in capaclty.

In order to obtain the desired efficiency, it is advantageous to place the elements of the condenser under suflicient pressure to insure that the intimate contact between the dielectric and conducting sheets effected as above described, will be maintained during use, but this involves some difiiculties if the volume of. the condenser is to be restricted to narrow limits. For example, if clamping plates be employed in op osite faces of the condenser stack and a su cient compression obtained by bolts or the like connecting said plates, it is necessary to have the plates overlap the stack sufficiently to accommodate the bolts, and to make the plates so strong and heavy that they will not how enough to unduly release the pressure on the central portion of the stack when the bolts are tightened up. Both of the above considerations tend to a construction of clamp which would be heavy and take up an undue amount of space, and the operations of assembling the condenser and placing it under proper compression, require special appliances and care- -iul work. Furthermore, if the condenser stack heats up in use, the expansion of the stack will also tend to how the clamping plates sa as release the pressure on the losses to be therein.

To facilitate the operations of assembling the condenser and placing the stack under the desired pressure, it is preferred to construct the condenser clamp of parts which will apply the necessary pressure merely by pressing or forcing them into proper position relative to each other. As shown, bearing plates 6 are employed on the opposite faces of the stack, such bearing plates having flat surfaces engaging the stack and being sufiiciently strong and rigid to distribute pressure over the area of the stack. In the present instance, the bearing members are made of metal, which is probably best suited to fulfill the requirements.

The compression is applied to the stack by means of members or clamps 7, each arched to extend around a side 0 the stack, and having opposed end portions 8 adapted to engage the outer surfaces of the bearing members 6 and pressing upon the same with sulficient force to maintain the laminae of the condenser in proper relation to each other. If desired, engaging parts may be provided between the members 6 and 7,' such as grooves 9, in the bearing members engaging the end portions 8 of the compression-applying members 7 ,to prevent accidental displacement of the latter.

If the clamp be employed in connection with condenser stacks which have previously been subjected to a high pressure, it is only necessary that the clamp bear on the stack firmly enough to insure that the elements of the condenser will not shift in use. However, if the condenser stack has some irregularities,such as small particles of wax on its surfaces,the pressure of the clamp will be sufiicient to take out such irregularities when the condenser becomes warm and hold the elements in proper shape thereafter.

The compression-applying members 7 are made of stiff material,ordinarily, metal, and are forced over the bearing members 6 with what might be termed a drive or force fit. Thus the forcing of members 7 over the bearing members places the condenser stack under the necessary pressure without necessitating the use of a press, or the tightening of bolts, to obtain thenecessary compression. In the present instance, the end portions8 of the members 7 are provided with inclined surfaces, edges or cutaway corners 10 so that the members may be readily driven into proper position by means of a hammer or the like.

As the clamp, in the particular form of the invention chosen for illustration, is independent of the circuit connections of the condenser, I have shown insulating sheets 11, for eXample ,of mica, interposed between both bearing members 6 and the stack to prevent short circuiting.

It is preferred to construct the bearing members and the compression-applying members 7 in such manner that compression is applied to the stack at points which are within the confines of the latter, so to speak. Thus the bearing members will not oe subjected to stresses which would tend to bow them,'either when the compression is applied or if the stack tends to expand in heating during use, since the pressure of the members 7 will be applied directly against the fiat face of the condenser stack. Furthermore, the application of pressure may be restricted to the confines of the active area of the condenser,that is, the overlapping portions of the conducting sheets i and 5,-- if it is found that the overlapping edges of the dielectric sheets, which are spaced apart a distance equal to the thickness of the conducting sheets, tend to give sufiiciently to bow the bearing members should compression be applied to points even with the overlapping edges of such sheets. If the compression be applied to the bearing members at points materially outside of the confines of the stack, the edges of the stack tend to act as fulcruins, with the result that the central portions of the bearing members are bowed outwardly so as to release the compression on the active area of the condenser, and the same tendency occurs when the heating of the condenser stack expands it.

The members 7 are preferably made of a metal,such as steel,-which is sufficiently springy to be spread or forced apart at the opposed end portions 8 of the members when they are adjusted to operative position, and sufficiently strong and stiff to give the necessary com ression. Thus, if the stack should expand due to heating in use, this expansion may be taken up by the members 7 without detriment. Ordinarily, the yielding of the clamping members of a condenser has a tendency to release the compression on one part or another of the active area of the stack, but with a construction of the above character, the bearin surfaces of members 5 and 6 will still be maintained parallel after expansion, and the members 7 will still exert the proper'amount of uni form compression upon them.

Since the bearing members need not be subjected to bending stresses, it is not necessary to make them of heavy weight, nor need they be extended to overlap the stack. The compression-applying members 7 are also of relatively li ht weight, and need be spaced from the si es of the stack only a sufficient distance to provide clearance, with the result that the clamp as a whole is comparatively light and occupies but a small amount of space.

'While a specific embodiment of the invention has been described, it will be obvious that many of the features of the invention are independently useful, and that many changes may be made without departin from the spirit of the invention as define in the following claim.

I claim:

'An electrical condenser comprising a stack of conducting and dielectric sheets, bearing members engaging the op osite faces of said stack, each of said mem ers having openended grooves in its outer face along its opposite edges, and clamps fonholdin said members and said stack together, said 0 amps having opposed edges and being disposed at opposite sides of the condenser, the edges of each clam engaging the ooves in the bearing members at each si e of the condenser, each clamp havin cutaway corners at the ends of its opposed edges, to enable it to be forced upon the condenser in'gripping position.

In testimony that I claim the foregoing, I have hereunto set my hand this 4th day of January, 1921.

- WILLIAM DUBI-LIER;

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