US2162925A - Process for making electric condensers - Google Patents

Description

June 20, 1939. F. wElss `PROCESS FOR MAKING ELECTRIC CQHDENSERS l Filed Jar.. 22. 1958 l INVENTOR. ,SFLix Llfzlss n ATTORNEY.

Patented .lime 2o, 1939 UNITED STATI-:s

PitooEss Fon MAKING coNnENsEns momo.

Felix weiss, Plainfield, N. J.. assigner to comen- Dubilier Electric Corporation, South Plainiield, N. J., a corporation of Delaware Application January 22, 1938, Serial No. 186.339

' s claims. (cria-1s) The present invention relates to an improved method oi and apparatus for punching a plu rality of pieces of desired angular conguratio from coherent sheet material. More specifically,

5 although not limited thereto, the invention is concerned with cutting a plurality of square or 'rectangular pieces of equal or different size .outf

of a sheet of insulating material s uch as' mica or the like for use as dielectric elements in the lo construction of electrical condensers. Single pieces of dielectric sheet materialof de-f sired equal or different shapes had to be punched heretofore from mica sheets or the like in such a way as to leave unused portions between the individual pieces. This Amethod of cuttinginvolved a substantial loss in material and furthervmore,due to the brittle or laminated structure ,of the material, particularly mica, the corners were often splintered or broken so that many of 2 the punched pieces had to be rejectedand could not be used. Furthermore, in the case of laminated material such as mica, the laminaeof the material became partially separated along the edges of the punched pieces due to the shearing and other stresses exerted thereon duringthe cutting operation.

Accordingly, it is an object of the invention to increase the eiiiciency of cutting or punching sheet material into pieces orunits of any desired shape especially from laminated brittle or easily splintered sheetssuch as mica or similar material. Another object -is to cut or punch such pieces oi.' angular shape from the stock material, especially laminated brittle or' easily splintering material such as mica, without waste of material between the punched pieces. Another object is to obtain in an eicient and easy manner exact shapes with-unbroken and 'unsplintered edges or corners. Y

These and further objects of the invention will 'become more apparent from thev following detailed description'taken with referenceto the 'accompanying drawing forming part of I :hisfspeci-V cation and wherein Figure 1 illustrates the mannerof cuttings.V numberv of rectangular pieces `from a sheet ofA Vmica or the,like in accordance with previous known methods, Figure 2 illustrates the cutting of such pieces in accordance with the improved method proposed by the invention, Figure '3 is.

varl isometric' view of a suitable combination' punching and cutting die for practicing the invention with the upperl die half removed, Figure 4 a cross-section through the complete cutting die taken on line 4-4 ofFigure 3,- and IigureY isa further cross-section of the complete cutting die taken pn line 5 -5 of Figure 3.

Similarreference numerals designate similar parts throughout the diierent views of the drawing.

Although many modications and uses of the invention will be apparent, for clearness of the specification the invention will be described particularly by way of example` asapplied to the cutting or punching of mica sheet material, but l0 it will be evident from the following that many modifications and variations may be resorted to diifering from the speciflc steps and'combination of elements described -herein for purposes of illustration.

- Reierring'more particularly to Figure 1 of the drawing illustrating the method of cutting rectangular pieces from a sheet as practiced in the I vhazard manner; that is, one at a time, the waste .due to unusable material between the cut eiements maybe still greater as is stood.

If in Figure 1 the pieces I0 were cut closely 30 adjacent to each other or in other words, if the.

readily underspaces I2 were reduced by the use of a suitable multiple cutting die, the corners I3' of the cutout. pieces would in many cases become torn or splintered and useless for many practical appli- 35 cations especially as dielectric elements o r plates in an electrical condenser. Furthermore, in the Vcase of laminated materialsuchf'as mica, vthe vlaminae may become partly separated along the edges such as indicated'by the dotted lineat Il o -m a mutable punching die. The punching pins and cooperating holes in theA punching die vare arranged in such amanner, that .the holes will be punched in the mica sheet at the corners of the desired square or rectangularpieces to be .cut out. Subsequently, the sheet is cut along straight-lines IG interconnecting the'holes Il thereby obtaining punched pieces of the desired size and configuration; that is, rectangular pieces in the example illustrated without the defects and diiiiculties encountered inthe previously known methods and substantially without loss o r waste of material.

Due to the' small size of the holes `l5 and the fact that the stresses on the edges and corners during the cutting operation are greatly reduced g results.

Furthermore, the elimination of sharp perpendicularcorners substantially prevents tearing oi the corners of the cut out pieces, and furthermore results in a. decrease of the friction between the elements and the walls of the punching die and in turn in increased resiliency of the edges of the elements thereby preventing to a marked degree a separation of the lamina' of the sheets along the cut edges as experienced with previous cutting methods pointed out hereinabove.

As will be apparent from theabove, byemploying' the principle and method of the invention, elements of `rectangular or any otherI shap'e may be cut from a sheet with the edges of the elements closely adjacent to or coinciding withV each other, thereby entirelyV eliminating the waste material due to the separating spaces required in past cutting operations. In this manner by the new method an approximate saving of about 30% of material is obtained.

` .The perforating and subsequent cutting of the sheets according to the invention may be carried out by means of any suitable punching and cutting die. A preferred and improved device of thistype is shown in Figures 3 to 5. The latter constitutes a combination of perforating and cutting or shearing units with means for ensuring the proper relative position of the sheet to be punched during the perforating and cutting operations, respectively, to ensure the cutting 'oi the sheet along connecting lines between the previously punched holes in above. A

Referring to the drawing, Figures 3 to 5', there is shown a cutting device having lower and upper base'members'or supporting plates 2|! and 2|.

The lower supporting plate 2U, has a punching die plate o r section 22 and an adjacent cutting or shearing section 23 ii'xed thereto. Similarly, the upper supporting plate -2|. carriespunching and cutting die plates 24 and 25, respectively, the

' former being arranged to cooperate with the lower punching die plate 22 andthe latter being ar ranged to cooperate with the-lower cutting or shearing die section 23. Numeral 26- represents a guide post or the like forproperly guiding the `*upper half or plate 2| of the die during the punching and cutting operations. 'The bottom die plate 22 of the hole punching unit is provided with holes 21 registering with pins 28 secured to or integral withthe -upper dief-plate 24. There is further shown a stripping plate 29 having perforations allowing freepassage of the pins 28 and resiliently mounted upon the plate 24 by means of pins or studs 30 arranged to pass freely a manner described herein through corresponding perforations in the plate 24. 'I'he pihs 30 are formed with enlarged heads arranged to move in correspondingly enlarged portions 3| of the vperforations in the plate 24. Resilient spacing members 30 such las strips of rubber or equivalent material are placed between the plates 24 and 29 and secured thereto such as by screws or rivets or in any other suitable mannel'.

The operation of the hole punching unit described is readily understood. When the upper die plate is moved downward by hand or by the aid of a power driven device, the pins 28 will Vpush through the mica sheet 32 and engage the holes 21 of the lower die plate thereby punching .out round holes from the sheet 32 in the manner as shown in Figure 2. When the upper die plate is again moved upwardly the stripping plate 29 having previously been pressed towards the plate 24 by compression of the spacing members 30 is pushed again downwardly due to theresiliency of the members 3D', thus stripping olf the mica piece 32 and preventing its sticking to or being torn or bent by the upward movement of the plate 24.

After the sheet 32 has been punched with holes in the manner described and arranged for instance such as shown in Figure 2, it is .moved to the shearing unit for cutting along the lines interconnecting the holes punched therein. as previously described. The cutting or shearing unit in the example illustrated comprises a lower part consisting of alternate stationary and movable rectangular elements or shearing blocks 35 and 36 respectively. The former `are rigidly iixed to or integral with the base plate 20 and the latter are arranged in snugly fitting but sliding relation between the fixed blocks for up and down movement against the action of resilient elements such as metal springs or rubber cushions 31 arranged between the lower faces of the blocks 36 and the base plate 20. 'I'he top part of the cutting die unit is the same as the bottom part described and comprises alternate stationary shearing blocks 38 fixed to the top supporting plate 2l and movable shearing blocks 39 held by pins or studs 4| ilxed tothezplate 2| and passing through perforations in the blocks 39. The latter perforations terminate in enlarged portions 42 adapted to receive the he'ads of the pins 4| thereby holding the blocks 39 in position and permitting the same`to move towards the supporting plate 2| against ,the action o f resilient cushions 40 similar as in the case of the blocks T36 of -the lower part of thedie. The top part 25 of the cutting die is furthermore arranged with its stationary shearing blocks registering with the movable shearing blocks 36'of the bottom part or section 23 and -vice versa with the stationary blocks 35 of the bottom section registering with the. movable blocks 39 of the top` section, in such a manner that when the die is closed, the stationary blocks 3,9 ofthe top part Y will force the movable blocks 36 of the bottom die may be carried out ina number of mannerssuch as'by. a suitable ,guide arrangement de- A 2,102,925 sheet u along the edges of the' blocks n, n, as,

39 and subdividing it into corresponding rectangular elements in the manner described. As pointed out, the mica sheet 32 or the like must be positioned and held in the cutting die in such a manner that the shearing edges of the die are in alignment with the holes 21 which have been previously punched in the sheet. .n

'I'he positioning of the sheet 32 in the punching die and corresponding positioning in the cutting scribed hereafter, or by punching -a number of positioning holes in the sheet tting over corresponding marking or positioning pins located in the'cutting die unit.

In the example illustrated in Figure A3, the positioning of the sheet in the respective dies is obtained in a more or lessautomatic manner. 'I'he sheet 32 is rst placed on a loading platform 46 with a portion extending beyond the platform as shown` A sliding clip having upper and lower elements or tongues." and 43 is fixed to a sliding member or block 50A moving upon a guide'.

rail 5| secured to a lateral extension of the bottom plate or support 2liV in such a manner that it may be moved from a position opposite to the loading platform `to a position opposite .to the punching die unit a n`d from there to av corresponding position opposite to the cutting die unit. Stops 52, 53 and 5I secured to the rail 5l serve "to x the positions of the block 50 or clip relative to the loading punching and cutting die units, respectively. YAtrip roller 55 having astop4 hinge section 55 allowing to drop the roller in a backward positionfis'secured to the base plate 2B in such aposition that as the block 50 is moved 'to the position in front of the loading- 'platform I6, the lower tongue 48 of the clip Passes over the roller 55 until its downwardly bent rear- A ward extension 49 engages the'roller at which time the clip jaws 55 and 51 open as the block A 50 is moved further forward toward the stop A position. The clip jaws 51 and 51 thus slip over 4:5

the extending pOltion of the sheet 32 and as the clip or block 50 is moved further in the same direction, the clip will spring into closing position thus firmly gripping the extension of the sheet 32.

The 'supportior the roller 50 may be held in a vertical vpizssiti'on by a coil spring having one end attached thereto and khaving its other end secured to the base plate-in such .a manner that as the block 50 is moved to the punching position, the end of the clip will trip'- the roller backwards and pass over the Asame without opening the' clip jaws. The lattermay be provided with teeth or prongs to ensure a iirm gripping of the mica sheet or the like thereby maintaining accu rate relative position of the sheet to be punched in the hole cutting and shearing die units re- After the holes 2i have been punched 'in the manner described,'the sheet 32 is'moved to the ,I cutting position by l releasing the stop elementv 53 andmoving the block 50 towards the right until abutting against the. stop element 5I.

While there'has been shown a particular com`.

I bination of elements to illustrate-,one way of -carrying out the invention, it is toA be clearly understood that any one of the elements can be used by-itself or with any other element besides those shown and illustrated, withoutdeparting ,from the scope of the invention. Moreover,'as will be evident from the above- 4the invention is not limited to the speciilc apthe appended claims.

rality of elements into which said sheet is to be sub-divided, a cutting die unit for cutting said sheet along lines connecting the holes punched therein, a movable support for said sheet, a guide for said support, and stop means for said support to position said sheet in the proper relative positions in said punching and cutting units.

2. In a device as claimed in claim l wherein said punching die unit comprises a pair of cooperating portions, one of whichis provided with a pluralityrol.' punching pins engaging correspondingholes in the other portion, and wherein said cutting unit comprises a plurality of adjacent shearing elements, land a pairof common Vsupportingmembers for the corresponding portions of said dies'.

3.In` a device of the character described, a

punching die unit for punching a plurality oi small holes in a sheetat the corners o f a plurality of elements .into which said sheet isto be sub-divided. a cutting die unit for cutting said sheet along lines connecting the holes punched therein, said punching die unit comprising cooperating lower and upper portions, one of said portions being provided with a plurality of punching pins engaging corresponding holes in the other `portion, said cutting die unit also comprising upper and lower` portions ,with -a plurality of cooperating adjacent shearing'element's, a pair of common'supporting members for the respective upper and lower portions of said dies, a carrier member slidably mounted and adapted. to rigidly hold the sheet 'to be cut, and stop means forjsaid carrier member for xing `the relative positions of said sheet in said punching and said cutting dies, respectively to cut said sheet along linesconnecting holes punched therein. A

4. In a device of the character described, means allel rows in a sheet, said holes dening lthe forpunching a plurality of small holes in parcorners of a plurality of` elements into which said sheet is to be sub-divided, further means for cutting said sheet along th'e lines connecting, said Iholes, said last'means comprising a pairV of co.-

operating unitseach unit comprising alternately iixed and -movable shearing members conforming to the shape of the'elements to be cut, the'iixed shearing members of one unitA registering with the movable shearing membersl of the other unit and vice versa, and means for positioning a sheet to be cut with respect to said iirst and second means', respectively, so that the holes 'punched by said ilrst means register with the respective meeting corners of the shearing members of said second means.

5. In a device "of the character described, means for punching a plurality of small holes in mutually perpendicular rows in a sheet, said holes defining the corners of a plurality of--rectangular elements into which said sheet is to vbe subdivided, further punching means for cutting said sheet along the 'linesy connecting said holes, said last punching meanscomprising apalr of co- Il operating units, each unit comprising alternately fixed and movable shearing members conforming to the shape of the elements to be cut, the fixed shearing members of one unit registering with the movable shearing members of the other unit and vice versa, and means for positioning a sheet to be cut with respect to said first and second means so that the holes punched by said first means register with the respective meeting corners of the shearing members of said last punching means. A

6. In a device of the character described, means for punching a plurality of small holes in mutually perpendicular rows in la sheet, said holes defining the corners of a plurality of rectangunormally flush with the fixed shearing members of the same unit and adapted to recede when eri--v '1 gaged by the cooperating fixed shearing members of the other unit during the closing of said further punching means, and means for positioning a sheet to be cut in said first and second punching means, respectively, so that the holes punched z by said rst means register with the respective meeting corners of the shearing members of said second means. y

'7. In a device of the character described, means for punching a plurality of small holes vin mutually perpendicular rows in a sheet, said holes defining the corners of a plurality of rectangular elements into which said sheet is to be sub-divided, further punching means for cutting said sheet along .the linesconnecting said holes, said last punching means comprising a pair of cooperating units, each of said units 'comprising alternately fixed and movable shearing members conforming to the shape of the elements to be cut, the fixed shearing members of one unit registering with the movable shearing members of the other unit and vice versa, a carrier member slidably mounted and adapted to rigidly hold a. sheet to be cut, and stop means for saidcarrier member for fixing the relative positions of said sheet in respect to said first and'second punching means so that the holes punched by said first means register with the respective meeting corners of the shearing members of said second punching means.

8. In a device of thecharacter described, means for punching a plurality of Asmall holes in mu-` i shape of the elements to be cut, the fixed shearvice versa, resilient supporting means for said movable shearing members in each unit, whereengaged by the cooperatingfixed members of the other unit during closing of' said last punch-l ing means, a carrier member' slideably mounted and adapted to rigidly hold a sheetl to be cut,

andstop means for said carrier member for fix-l ing the relative positions of said sheet in respect to said first and second punching means,

whereby the holes punched by said first punch-y ing means register with the respective meeting corners of the shearing members of said second punching means.

FELIX WEISS.

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