US1606760A - Method of and apparatus for bending filaments - Google Patents

Description

T. R. GRIFFITH METHOD OF AND APPARATUS FOR BENDING FILAMENTS Filed Oct. 10 1924.

Patented Nov. 16,1926.

UNITED" STATES PA,.TEN T, ,QFHCE. 4

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METHOD OF AND APPARATUS. FOR BENDING FILAMENTS.

- Application flledIOctobernlO, 1924. SerialNo. 742,756..

This invention relates to .a method and apparatus for bending and forming refractory material and particularly refractory: filaments such as are used in high power 6 electron discharge devices.

It has for an object to facilitatethe transformation of a .lon length of refractory wire into a desirahle form, such as M.- shaped or V-shaped filaments for the above purpose.

This object is attained by providing a metallic standard having a hand operated plunger which insulatingly supports a plurality of electrode jaws and a bending frame which carries a measuring voke and: a re movable lnsulatlng plate. A filament wire is laid in a slot in the insulating plate and the lunger lowered until it contacts with the lament wire, whereupon a circuit isestablished between the electrodejaws and the portion of the wire between. the jaws is heated and bent over the insulating dplate. The bent filament wire is remove from the frame and the bent portion placed over the ,5 hook on the measuring yoke, the parallel strands of the wire being laid in "the slots of the insulating plate andathe plungpr again lowered to bend the wire to form. t e filament in the desired shape in which it 80 will be used in an electron discharge device. A filament formed in this manner can be attached to the filament supporting structure in the device without any truing up or measurements of the length of the strands between bends. Y

Referring to the drawin s: Figure 1 is a side view 0 the bending jig made in accordance with this invention. Fig. 2 is an enlarged. sectional front view with the filament wire held: in position.

Fig. 3 is the same as Fi 2' but showing the plunger in its operate position.

Fig. 4 is an enlarged plan view of a section of the 'ig illustrating the second step of the hen ing operation.

ig. 5 is a front view of Fig. 4 showing the bent filament in dottedlines, and.

Fig. 6 is the com an apertured extension bent at right angles lete bent filament readyto be inserted in a igh power electron disto the standard. through whichv bolts are passed to fasten the standard to a base or work bench 2. An. apertured metallic block 3.. is fastened to the standard 1 adjacent the upper end thereof and forms. a" guiding member -for the plunger rod 4, which. is attached to the hand operated lever 5 carried 'atthe upper end of the standard 1. A n

slot 6 is provided on one longitudinal surface of the plunger rod 4 and a set screw 7, fastened through the guidemember 3, limits the upward and downward movement of the plunger rod 4. An integral bifurcated extenslon 8 on the lower end of the plunger 4 is provided with apertures to receive a locking screw to su port an insulating block 9, preferablv of lavite. The insulating block 9 is 0 such formation as to provide a rigid continuation of the plunger I 4 and insulatingly su ports metallic electrodes 10 and 11 whic lower end of the insulating block 9. The electrodes 10 and 11 are supported from the block 9 by means of a screw 12 passing through the electrodes and the insulating block 9. The electrode 10 is insulated from electrode 11 by having a larger bore through which the screw '12 passes and being in sulated from the screw 12 ,by insulating washer 13. Suitable electrical connections 14 and 1 5 are attached to the electrodes and connected to any desirable source of po wer. The contacting surfaces of the electrodes 10 and 11 are curved inwardly to prevent the electrodes cutting the filament wire in. the bending operation to be described hereinafter.

A rectangular metallic frame 16 having an extension 17 bent at right angles to the plane surface of the frame is arranged in an edgewise position with respect to the plunger rod 4. and attached to the frame by means.

of bolts and nuts. The frame 16 is positioned on the standard in such a manner that when. the'plunger is lowered the electrodes 10 and. 11 pass on either side of the edge of the frame 16. A portion of the frame is cut away to provide a seat for insulating plate 18,. which is preferably of lavite, the plate being provided with a rounded edge having indentations 19. A pair of metallic guiding strips 20 are attached to the frame on one side of the cut portion, the upper ends are carried at the i of the strips projecting above the edge of the frame and one side of the guiding strip ,1 projecting over the edge of the cut portion of the frame. A pair of similar guiding strips 21 are attached to the frame on. the opposi with t e strips form a pocket for the insulating plate 18. This construction pro-' vides suitable means for replacing the nsulating plate 18 in the event of breakage or 22 and 23 through which pins 24 and 25 extend to carry movable bearin s 26 and 27. The movable bearings 26 and 2 are be descri bed. A. filament wire I tory material, such! as tungstem'of suitable length to form a filament, is laid across the bending frame 16 and positioned in one'of "the slots 19 in the insulatin plate*18l'-- The lever 5 is operated, where ythe plunger su'lating' plate positioned in said frame,"re'-I j 11 contactwith the filament wire A. This" v o ratiorigiestablishes a' metallic circuit t rou h the'electrode jawlO, a portion of the lament wire and electrode jaw 11, whereby the portion of the filament wire between the electrode jaws is heated to a red. 1 glow, andpressure is then applied to the again lowered until. the elect with the strands B and C and a circuit es-' tablished to heat the portions-of'the strands between the electrode jaws. The plunger is, further '0 erated to bendthefilament wirev over the rame and the pl I to removekthe filament wire m the bend-. ;W be b swmgmg 3 provided with vapertured extensions 28 and 29 to which is attached a measuring yoke 30 by means of rivets." A hook member 31 pro-;: jects from the upper surface of the yoke 30 and is positioned near the converging point of the arms of the yoke. The normal position of the-yoke is generally in a substan-.

tially parallel plane'with the frame 16 but in its operated position is swung up at right angles to the frame and lies in a'plane sub-' stantially the same as the edge of the frame; This arrangement provides a jig which may be used for bendin both V and M shaped filaments since the oosely' pinioned yoke is only used when the M shaped filament is de sired.

The operation of thebendingiigwill how is lowered and the electrode jaws 10 and plunge'ritd bend the filament wire over' the frame'to complete the first operation. The

' a standard, "a bending frame attac ed to filament wire'is removed from the frame and comprises two strands B and C in substantiallglparallel-relation." The bent portion of the anient wire is hooked over the pin 31 (in ,the 1measuring joke 30 and the yoke swung n to a plane approximately the same as't e edgeofthe bending frame, and

the strands B and C laid in the slots 19 in the 'insulatinggplate 18. The lunger is escontact side of the cut portion and together trodes carried bv 'said vtached to said stan of refrac- 5 yoke carried by said frame. 1

r withdrawn ing frame. The filament wire nowcomprises four strands, B, C, D' and E,"as shown in Fig. 6, and is formed into the desired shape in which it will be used. in a high power electron .discharge device.

Althoughh-this invention has been d-F scribed with reference to theibendin and;

cation forming of a highlyirefractory ment it is within the; V to bend other forms'of'refra l1 and other metals in wire form' -in whi "desired to electrically heat" andbend portions of the Wire to form desirable shapes'and configurations. t: a. H

\Vhat is claimed is 4 1. A filament; forming -apparatus c-om prising a standard, amovablelunger'attached to saidstandarch-"a plura ity of elecglunger, a frame atard, a removable grooved. insulating plate 1. carried by), said frame, and a yoke looselymounted on said;- am'ent' in adjuste'dj position on said plate. 4

frame for holding the fi 25A filament bending device I a standard, -a lever attached-to said stan ard, a" plunger carried by'said lever, guid- 7 ried by said insulating block, a metal-frame arranged edgewise with res act to said plunger and attached to sai standard, a removable insulating plate,"means on said frame to support said plate, and aswinging 3. A filament bending device comprisin ard:- -intermediate the ends thereof, in-

taining means for said plate attached to a standard, aframe attached to said stan said frame, bearings carried by'said frame,

a swinging yoke, supported from said bearin a guide block attached to said standar agplunger slidably mounted in said lock,-{ ineansfor operating said lunger, anda-fplurality of metallic electrod ds insulatingly supported by said plunger.

4. A filament bending device com rising said standard, -an insulatin plate carried by said frame, said platebem'gadapted to receive a filament wire to be bent,- a. slidable plunger carried by said standard, ,aniinsuating block carried by'said plugger, and :a lura ity of electrodes support I b said lock, whereby the contact of saifelec 5. A filament bending device comprising a standard, abending frame attac d its I said standard, an insulating plate carried-Q} by said frame, said plate adapted to receive -'11 supported at either side of said plate, a pin carried by said yoke, said pin being adapted to carry the filament wire, said yoke being swung in the same plane as the edge of said insulating plate, the parallel strands of the filament being laid on said insulating plate, anda slidable plunger carried by said standard and adapted to apply pressure to the filament wire whereby the filament wire is bent in the form in which it will be used in vacuum tubes.

6. The method of bending and forming a refractory wire which comprises laying said Wire on a bending frame having a swinging yoke, lowering a plurality of electrodes in contact with said wire, applying pressure to portions of said wire to bend said wire over said frame, removing the bent wire from the frame, attaching the bent portion to said yoke, elevating said yoke to the plane of the edge of the frame, positioning the two strands of the bent wire across said frame, and thereafter lowering the electrodes on said strands to bend said strands over said frame.

7. A bending device comprising a standard, a frame. attached to said standard, said frame having a removable insulating plate to receive a wire to be bent, a plunger mounted on said'standard, a plurality of electrodes carried by said plunger cooperating with said plate and a movable yoke for positioning said wire on said plate.

8- A bending device comprising a stand ard, a frame attached to said standard, said frame being adapted to receive a wire to be bent, a plunger carried by said standard, a plurality of electrodes supported by said plunger and adapted to heat and bend the wire over said frame, said electrodes passing on either side of said frame.

In witness whereof, I hereunto subscribe my name this th day of September, A. D. 1924.

THOMAS R. GRIFFITH.

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