US2298766A - Electrical condenser - Google Patents

Description

Oct. 13, 1942. c. M. JORGENSEN 2,298,766

ELECTRICAL CONDENSER 'Fi'led Jan. 6, 1941 2 Sheets-Sheet l I1 6 vezo Z GiZ Qrziefjf Jaye/58 4 Oct. 13, 1942. c. M. JORGENSEN 2,298,766

ELECTRICAL CONDENSER Filed Jan. 6, 1941 2 Sheets-Sheet 2 7 caw aflw #2 2 Patented Oct. 13, 1942 UNITED STATES PATENT OFFICE Electric & Mfg. 00., Inc

., Chi ag IlL, a corporation of Illinois Application January 8, 1941, Serial No. 873,235

9 Claims.

The present invention relates to electrical condensers, and is particularly concerned with adjustable electrical condensers of the type which have a relatively small range of adjustment, and which are usuallyadjustedto predetermined capacity at the factory. Such electrical condensers have been called "padders in the trade.

One of the objects of the invention is the provision of improved electrical condensers of the type having a limited range of adjustability, which are primarily intended to be set at the factory at desired capacities.

Another object of the invention is the provision of electrical condensers of the class described, which have a high degree of mechanical stability, and which are adapted to maintain their capacity at the predetermined value for a long period of time, with a minimum amount of drift.

Another object of the invention is the provision of an improved condenser structure in which the'mica plates are protected and aligned and their rotation is prevented by the structure of the clamping plates, land in which improved means is provided for mounting the condensers on the chassis without a bracket.

Another object of the invention is the provisionof an improved condenser structure which provides better control of stability, and in which.

the condenser may be provided with any lengths of soldered leads, or constructed with any number of insulated plates.

The riveted connectors of the prior art, which have been used with condensers, tend to oxidize, which changes their capacity and renders the oxidized plate inoperative.

Another object of the invention is the provision of an improved condenser structure which is simple, emcient. capable of economical manufacture, and which is peculiarly adapted to be utilized as the by-pass condenser for the aerial of a radio receiving set having a direct connection which reduces the inductance and increases the capacitors e fl'ectiveness.

Another object of the invention is the provision of an improved condenser structure by means of which a multiplicity of condensers may be placed in one assembly for the purpose of producing results equivalent to a series of condensers used in some electrical circuits, thereby reducing efiective inductance introduced in the circuits by the necessity of connecting several condensers into the assembly.

Other objects and advantages of the invention will be apparent from the following description and the accompanying drawings, wherein similar characters of reference indicate similar parts throughout the several views.

Referring to the drawings, of which there are two sheets.

Fig. 1 is an enlarged bottom plan view of a condenser constructed according to the invention, mounted on a portion or the chassis;

Fig. 2 is a/ top plan view of the chassis, with parts of the condenser exposed for access;

Fig. 3 is a vertical sectional view, taken on the plane of the line 8-4 of Fig. 1, looking in the direction of the arrows;

Fig. 4 is a horizontal sectional view, taken on the plane of the line 4-4 of Fig. 3;

Fig. 8 is a fragmentary sectional view, taken on the plane of the line 5-5 of Fig. 2;

Fig. 6 is a bottom plan view of another modifled form of structure, which is provided with a plurality of condensers in one assembly;

.Fig. 7 is a side elevational view of the assembly of Fig. 6;

I18. 8 is a view similar to Fig. 6 of another modification, which is provided with a bracket for the mounting of the condenser on a supporting bar or the like:

Fig. 9 is a side elevational view of the assembly of Fig. 8; and

Fig. 10 is a plan view of a condenser embodying the invention, secured to the aerial jack of a radio receiver for the purpose of providing a more direct connection to reduce inductance and increase capacitors eifectiveness.

Fig. 11 is a side elevational view of the structure of Fig. 10;

Fig. 12 is a sectional view, taken on the plane of the line i2-i2 'of Fig. 11;

Fig. 13 is a side elevational view of another modification of the type shown in Fig. 4, which is provided with an improved form of supporting bracket;

Fig. 14 is a plan view of one of the condenser Plates;

Fig. 15 is a plan view of one of the sheets of mica;

Fig. 16 is a fragmentary sectional view, taken on the plane of the line l8l8 of Fig. 2.

It should be understood that the condensers may be mounted above or below the chassis, butfor the purpose of this description that side of the condenser having the head of the adjusting screw exposed has been termed the top.

Referring to Figs. 1 to 3, 20 in this embodiment indicates a sheet metal plate which forms a part of the supporting structure of the chassis. It is preferably provided with a pair of relatively long rectangular slots Ii, 22 oppositely located 55 with respect to an enlarged centrally located circular aperture 23.

The slots 2i and 22 are so located that when the head 24 of the condenser screw bolt 25 is accessible and centrally located in the aperture 23,

0 the lugs 28 and 21 of the condenser assembly 2 aae'a'me register with the apertures 2|, 22, through which they are passed.

The plate 23 is also preferably provided with a pair of oppositely located circular apertures 23, 23 for receiving the lugs 33, 3| carried by side 5 walls of the condenser.

The condensers constructed according to the invention preferably comprise the two clamping plates 32, 33, and the clamping plate 32 may be octagonal in form and provided with four spaced side wall flanges 34 to'31. g

The side wall flanges 34 to 31 extend at right angles to the body 01' the plate 32, and are located on alternate sides ofthe octagon which forms the border of theplate. This leaves open 5 spaces in the side wall between each of the flanges 34, 35; 35, 33; 33, 31; 31, 34, through which the connector strips of the condenser plates may project with a clearance.

The side wall flanges 34-31 may be provided with straight flat ends as in the embodiment of Figs. 6 and 7; but in the embodiment of Figs. 1 to 4 these side wall flanges carry the additional lugs which-are used to attach the con- -denser to the chassis plate 23. Thus the side wall flanges 34 and 36 may carry the lugs 33 and 3|, which project into the apertures 23 and 23 of the chassis plate 23 and prevent rotation of the condenser on the plate 23.

The side wall flanges 35 and 31 may carry the lugs 23 and 21, which are of greater width, being of a size adapted to pass through the apertures 2| and 22, with which they register when the lugs 33 and 3| are in the apertures 28 and 29. The lugs .26 and 21 are formed with 35 laterally and inwardly extending slots 38. These slots have their side wall, which is nearest to the end of the lug 23 or 21 so located that it will engage the face of the plate 23 when the-condenser has the ends of the flanges 34-31 engaging the other side of the plate.

Thus the lugs 23, 21 may be inserted through the apertures 2|, 22, and the portions 39, 43 of these lugs may be bent laterally to retain the condenser on the plate. It is the presence of 45 the slots 33 which renders it desirable to provide the lugs 33 and 3| for preventing rotation.

The slots 33preferably slope downward and from the edge of each lug, shown in Fig. 16, so

that the sloping surface 4| on each lug 33 or 43 5 serves to cam the condenser tightly against the plate 23.

The plate 32 is provided with a centrally located aperture 42, which is threaded to receive plurality of radially extending slots, preferably 6 equally spaced. In the embodiment illustrated they are at right angles to each other. These slots 44, 45 serve to give that portion 45 or the plate 33, which is between them, a greater resiliency, so that the plate may be slightly dished outwardly from the condenser assembly at the parts 45.

If it were not for the slots 44, 45, the dished formation in the plate 43 would necessarily be condenser plates and mica sheets with the same resiliency as the present structure.

Referring to Fig. 14, this is a plan view of a thin brass condenser plate 41 .utilized in the condenser assembly. It has a hexagonal body 43 of slightly smaller size than the plate 33, and of course it is smaller than the inside of the housing which is formed by the plate 32 and flanges 34-31, so that there will be a clearance between the condenser plates and the housing.

The condenser plates all have an enlarged centrally located aperture 49, which passes the screw bolt with a relatively large clearance to prevent contact between the condenser plates and the adjusting screw bolt.

The body 43'of each condenser plate has a laterally projecting flange or tab 53, which projects laterally from one of the flat sides and serves as a connector. It also serves the purpose of holding the plates in alignment in a jig while the condenser is being assembled.

The tab 53 may be described as substantially rectangular in plan. It is provided with a pair of inwardly extending and ODPO itely located rectangular slots 5|, 52. These serve to receive a clip which holds the connecting wire to the condenser, and which holds the tabs in alignment.

The tab or flange 53 also has a centrally located aperture 53, which is adapted to receive the laterally turned end 54 or a connecting wire or loop 55, which serves to secure together one or more different plates, forming a strong mechanical connection preliminary to soldering.

Referring to Fig. 15, this is a plan view of one of the mica plates. It is also octagonal in form, being provided with the sides 56 of greater length and the sides 51 of smaller length. This gives the mica plates such a shape that the portions bounded by the sides 51 project slightly, as shown at 58, from the housing between the side walls 34-31, increasing the width of these insulating plates at the point where the terminals 53 project from the housing.

The condenser may be built up of any number of metal plates and dielectric plates, the mica plates being interposed between the metal plates.

The preferred practice is to have the outermost brass plates bearing against the heavy clamping plates 32, 33 above and below so that the heavy plates, that is, the housing 32 and the pressure plate 33, are common to one side of the condenser.

In other embodiments, however, a heavy mica plate may be inserted between the brass plate and the housing, above and below, so that the housing is also insulated from all of the brass plates.

The method of assembling the condenser is as follows: The housing 32 is first placed upon a suitable jig or support, the jig being provided with shoulders for locating the housing, and with upwardly extending lugs suitably located 5 with respect to the housing and adapted to be received within the slots 5| and 52 of the brass plates,- to be assembled with the housing. Two lugs may be provided on each of the four open sides of the housing, so that when it is desired to have the tabs 53 project from all four sides, as shown in Fig. 6, this can be done.

Referring to a simple embodiment, such as Figs. 1 to 3, the brass plates and mica plates are then alternately placed inside the housing 32.

very stiff and the plate would not clamp the The mica plates are maintained in proper alignaaoares ment with their centrally located aperture aligned with the screw aperture 42 by the side walls 34-" which the edges of the mica sheets engage.

The brass plates are maintained in proper alignment inside the housing by the lugs of the Jig, which flt in the slots II, I! of the tabs ll. After a suitable number of mica sheets and brass plates have been placed in the housing, the pressure plate II is placed on top and the screw 2| inserted into the threaded bore 42 and driven home to clamp the brass plates and mica plates together by means of the pressure plate It.

The condenser may thenibe removed from the Jig and completed by inserting the wires N with their laterally turned ends is extending through the registering apertures ll. With the wire in this position a sheet metal cli ll is'bent about the wire II, and tabs II, the clip being of suiflcient width to fit inside the aligned slots II, I! of the assembly of brass plates, and the clip has its upper side bent to substantially cylindrical shape at II to at about the wire.

Below the assembly of connector flanges ll the clip I! has its ends bent over toward each otherat 8i so that the wire is clamped in place with its end projecting through the apertures II.

The clip and the wire are then covered with solder on the upper and lower sides so that the clip is soldered to the wire and to the condenser flanges l0, and the various condenser flanges are also soldered together, leaving the wire ll prosion ll.

means of this connection than any other. Before the condenser leaves the factory, its adjustment screw 25 is so adjusted that the condenser has the desired predetermined capacity. The various mica sheets and plates are held in proper position and clearance with respect to the screw by the frictional engagement between these sheets under the clamping action of the plate 33 and housing 32. They are also held in predetermined position with respect to each other by the fact that all of the condenser plates which have a flange projecting from one side are secured together at that flange by soldering and by means of the wire and clip in such manner that the plates cannot get out of alignment.

The condenser plates have a relatively large clearance around the screw, due to the size of the aperture u, but the mica plates have a smaller aperture so that they project inwardly beyond the border of the aperture ll of each condenser plate. The mica aperture is, however, preferably slightly larger than the threads of the screw, so that the threads will not tear the mica.

Referring to Figs.'6 and 7, these are views of a modification in which condenser plates insulated from each other have connector flanges extending from all of the four sides of the assembly, and in fact two condenser plate assemblies at the left of the figure are provided with two separate wires it, 03. Thus, a multiplicity of condensers, insulated from each other, but in electrostatic relation with respect to each other, may be secured in the same assembly.

There are-various forms of nlter and resonant circuits which these condenser assemblies serve to replace at a minimum cost, and with a high degree of emciency.

\ Referring to Figs. 8 and 9, these are views of a modifled form of condenser which is provided with an attaching bracket II for attachment to the bars or plates of a supporting chassis. In this embodiment the bracket ll comprises a plate having arect ngularbodyandhayingtheupwardly extending rectangular tabs '0. The body of theplate is soldered, brazed, or otherwise secured to the housing, and has a centrally located aperture for passing the screw bolt II.

The plate to which this bracket is secured is indicated at I, and it comprises a strap of metal which has an aperture 61 for clearance with respect to each of the screws of the condensers that are attached to it. It is attached by bending the flanges I! over and about the strap II in such manner as to secure supporting member ll. 1

Referring to Fig. 13, in this embodiment the housing of the condenser has an angular bracket ll, comprising a strap of metal which is bent at right angles at H, and which hasjone portion again provided with an aperture 12 for clearance about the screw bolt 2'.

the condenser to the The end portion I3 is soldered or otherwise secured to the housing 32, and the upwardly extending leg ll of the bracket has an aperture II a pressing operation, which also forms a depres- The protuberance TI is received in a complementary aperture II in the supporting plate ll of the chassis. 4

Referring to Figs. 10-12, this is a modification in which the side walls I441 of the housing have been eliminated and the two heavy plates II, II serve as condenser plates. The heavy plate II is similar in structure to the housing I! in that it is provided with a threaded aperture for receiving the threaded endof the screw bolt 81.

It also has an oifset narrower flange II, which carries a partially cylindrical flange "that flts about the outside of a jack ll, such as may be used for connection to an aerial in the radio receiver of an automobile.

The single condenser plate ll may be circular, and may have an enlarged centrally located aperture ll, as described in Fig. 14, and a downwardly extending connector tab 02 which extends between the two flanges I! of the connector of the Jack.- I

The flanges I: have an aperture 94 so that a wire extending through these apertures may also engage the connector tab 01 of the condenser. The pressure plate I! is circular and provided with slots 44, 45, as shown in Fig. 4; and mica sheets are, of course, interposed between the condenser plate !I and each of the plates II, II.

This condenser provides such a short and direct connection between its elements and the Jack connectors that the leads of this condenser have v a minimum amount of inductance, and the condenser assembly is very effective as a by-pass condenser for the jack of an aerial of an automobile radio receiving set.

The dimculty with most condensers for this purpose is that the leads are too long, and for high frequency currents such long leads would increase the inductance. of the by-pass circuit by such an amount that the capacity of the condenser would be cancelled out and substantially ineffective.

In the present embodiment, however, the bypass condenser has maximum effective capacity,

and economical mode of connecting the device in circuit. As a mechanical joint is provided first, and the plates are then sweated together with solder. the wire is firmly and permanently secured to the condenser plates, and the assembly may be furnished with any reasonable length of wire desired. This renders the present condenser assemblies more salable than the devices of the prior art in which a long soldered lug or wire is riveted to the condenser plates.

The present condensers are provided with various convenient structures for securing them to the chassis, and with means for indexing and preventing rotation of the condensers on the chassis. While these condensers are best adapted for capacities of, for example, from 300 to 6,000 microfarads, they can also be built to high capacities and to lower capacities. The assemblies in which a multiplicity of condensers are embodied in one structure are adapted to replace various types of fllters and other circuits utilizing condensers, and to perform the same function efficiently, at a very low cost.

WhileI have illustrated a preferred embodiment of my invention, many modiflcationsmay be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but desire to avail myself of all changes within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

1. In an electrical condenser, the combination of a housing of substantially octagonal form, said housing having four open sides and four sides closed by upwardly projecting flanges, a plurality of condenser plates and mica insulating plates alternately disposed and located in said housing, a pressure plate above the assembly of said condenser plates and mica plates, a screw bolt passing through said pressure plate and threaded into said housing plate, said condenser plates having laterally projecting connector flanges extending through the open sides of said housing and adapted to be used for connecting the plates in circuit.

2. In an electrical condenser, the combination of a housing of substantially octagonal form, said housing having four open sides and four sides closed by upwardly projectingflanges, a plurality of condenser plates and mica insulating plates alternately disposed and located in said housing, a pressure plate above the assembly of said condenser plates and mica plates, a screw bolt passing through said pressure plate and threaded into said housing plate, said condenser plates having laterally projecting connector flanges extending through the open sides of said housing and adapted to be used for connecting the plates in circuit, said pressure plate having a dishedformation adjacent its aperture and having radially extending slots for increasing the resiliency of the dished formation.

3. In an electrical condenser, the combination of a housing of substantially octagonal form, saidhousing having four open sides and four sides closed by upwardly projecting flanges, a pin--- rality of condenser plates and mica insulating plates alternately disposed and located in said housing, a pressure plate above the assembly of said condenser plates and mica plates, a screw bolt passing through said pressure plate and threaded into said housing plate, said condenser plates having laterally projecting connector flanges extending through the open sides of said housing and adapted to be used for connecting the plates in circuit, said mica plates fitting substantially in said housing, and said condenser plates having a clearance with respect to said housing and being maintained in predetermined position by frictional engagement with the rest of the assembly under the clamping action of said screw bolt.

4. In an electrical condenser, the combination of a housing of substantially octagonal form, said housing having four open sides and four sides closed by upwardly projecting flanges, a plurality of condenser plates and mica insulating plates alternately disposed and located in said housing, a pressure plate above the assembly of said condenser plates and mica plates, a screw from eachother by slots, said plate having a centrally located threaded aperture, a plurality of metal condenser plates and a plurality of insulat ing sheets arranged alternately in a stack to insulate said condenser plates from each other and from said housing plate, said insulating sheets being shaped to engage said guide flanges, and a pressure plate engaging the assembly of insulating plates and condenser plates, said pressure plate having a centrally located aperture surrounded by a dished portion and having radially extending slots extending from said aperture in said dished portion, and a threaded metal member extending through said pressure plate and threaded into said housing plate to place a predetermined compression upon the assembly of the insulating plates and condenser plates, said condenser plates being formed with integral radially extending connector portions and said condenser plates being arranged in at least two series of plates, the plate of each series being insulated from the plates of the other series and the plates of difierent series having their connector portions extending through diiferent slots in said hous'ng,

and means for securing said connector portions together to assure the location of said condenser plates in said assembly with the condenser plates out of contact with the threaded member and the housing flanges.

6. In an electrical condenser the combination of an external housing plate having a plurality of transversely extending guide flanges separated from each other by slots, said plate having a centrally located threaded aperture, 9. plurality of metal condenser plates and a plurality of insulating sheets arranged alternatively in a stack to insulate'said condenser plates from each other and from said housing plate, said insulating sheets being shaped to engage said guide flanges, and a pressure plate engaging the assembly of insulating plates and condenser plates, said pressure plate having a centrally located aperture surrounded by a dished portion and having radially extending slots extending from said aperture in said dished portion, and a threaded metal member extending through said pressure plate and threaded into said housing plate to place a predetermined compression upon the assembly of the insulating plates and condenser plates, said condenser plates being formed with integral radially extending connector portions and said condensed plates being arranged in at least two series of plates, the plates of each series being insulated from the plates of the other series and the plates of different series having their connector portions extending through different slots in said housing, and means for securing said connector portions together to assure the location of said condenser plates in said assembly with the condenser plates out of contact with the threaded member and the housing flanges, said condenser plates having their connector portions formed with through apertures and said through apertures being placed in registry and engaged by the end of a through connector wire.

7. In an electrical condenser the combination of an external housing plate having a plurality of transversely extending guide flanges separated from each other by slots, said plate having a centrally located threaded aperture, a plurality of metal condenser plates and a plurality of insulating sheets arranged alternately in a stack to insulate said condenser plates from each other and from said housing plate, said insulating sheets being shaped to engage said guide flanges, and a pressure plate engaging the assembly of insulating plates and condenser plates, said pressure plate having a centrally located aperture surrounded by a dished portion and having radially extending slots extending from said aperture in said dished portion, and a threaded metal member extending through said pressure plate and threaded into said housing plate to place a predetermined compression upon the assembly of the insulating plates and condenser plates, said condenser plates being formed with integral radially extending connector portions and said condenser plates being arranged in at least two series of plates, the plates of each series being insulated from th plates of the other series and the plates of different series having their connector portions extending through different slots in said housing, and means for securing said connector portions together to assure the location of said condenser plates in said assembly with the condenser plates out of contact with the threaded member and the housing flanges, said latter means comprising a metal clip secured about said connector portions and engaged in lateral slots of said connector portions.

8. In an electrical condenser the combination of an external housing plate having a plurality of transversely extending guide flanges separated from each other by slots, said plate having a centrally located threaded aperture, a plurality of metal condenser plates and a plurality of insulating sheets arranged alternately in a stack to insulate said condenser plates from each other and from said housing plate, said insulating sheets being shaped to engage said guide flanges, and a pressure plate engaging the assembly of insulating plates and condenser plates, said pressure plate having a centrally located aperture surrounded by a dished portion and having radially extending slots extending from said aperture in said dished portion, and a threaded metal member extending through said pressure plate and threaded into said housing plate to place a predetermined compression upon the assembly of the insulating plates and condenser plates, said condenser plates being formed with integral radially extending connector portions and said condenser plates being arranged in at least two series of plates, the plates of each series being insulated from the plates of the other series and the plates of different series having their connector portion extending through diiierent slots in said housing, and means for securing said connector portions together to assure the location of said condenser plates in said assembly with the condenser plates out of contact with the threaded member and the housing flanges, said latter means comprising a metal clip secured about said connector portions and engaged in lateral slots of said connector portions, and said metal clip and connector portions being soldered together.

9. In an electrical condenser the combination of an external housing plate having a plurality of transversely extending guide flanges separated from each other by slots, said plate having a centrally located threaded aperture, a plurality of metal condenser plates, and a plurality of insulating sheets arranged alternately in a stack to insulate said condenser plates from each other and from said housing plate, said insulating sheets being shaped to engage said guide flanges, and a pressure plates engaging the assembly of insulating plates and condenser plates, said pressure plate having a centrally located aperture surrounded by a dished portion and having radially extending slots extending from said aperture in said dished portion, and a threaded metal member extending through said pressure plate and threaded into said housing plate to place a predetermined compression upon the assembly of the insulating plates and condenser plates, said con denser plates being formed with integral radially extending connector portions and said condenser plate being arranged in at least two series of plates, the plates of each series being insulated from the plates of the other series and the plates of different series having their connector portions extending through different slots in said housing, and means for securing said connector portion together to assure the location of said condenser plates in said assembly with the condenser plates out of contact with the threaded member and the housing flanges, said condenser plates having their connector portions formed with through apertures and said through apertures being placed in registry and engaged by the end of a through connector wire, said latter means comprising a metal clip secured about said connector portions and engaged in lateral slots oi said connector portions, and said metal clip and connecto portions being soldered together.

CARTHER M. J ORGENSEN.

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