US2068628A - Apparatus for trimming grid electrodes - Google Patents

Description

Jan. 19, 1937. H. P. KRONENWETTER ET AI. 2063523 APPARATUS FOR TRIMMING GRIDELECTRODES Filed June 12, l935- III Q ililiill INVENTOR S ""'TORNEY Patented Jan. 19, 1937 PATENT OFFICE APPARATUS FOR TRIMMING nuzcxmonrcs Harold P. Kronenwettel' and Ea.rl E. Moore, Emporium, Pa. assig'n0l's to Hyxrade Sylvania.

Corporation, Salem, Mass.

Massachusetts a corporation n! Applibation Junel2, 1935, Serial N0. 26,235

11 Olaims.

electrodes, as examples of such machine s may be mentioned these illustrated in Patent N0. 15 1814'770 and Patent N0. 1897460.

It has been the customary practice heretofore in winding grids in continuous grid-strips to' fasten the individual turns or lateral wlres to the grid side-rod or side-rods by a welding, peen-' 20 ing or swaging operation, and to leave one or more turns unfastened so that the grid strip may be cut into unit lengths with the side-rods extending beyond the lateral wires. 'prior machines thisresults in the leaving 01' a 5'considerab1e 1oose length cf the cut end of the lateral wire, a.nd has necessitated. the services of an operative who manually trims the 1oose unfastened ends, but in order to facilitate thi manuell trimming operation it has been found 30 necessary to leave more than one grid turn unv fastened so that the operative may have sufficient length of wire to grasp during the trimming operation. Where a large number of grids are be1ng manufactured these trimmed turns- 35 become waste products and add appreciably to the cost of the flnished'tube'into whichthe grid is incoiporated. Apart from the increased cost is the fast that with the ordlnary manuizl method of trimmixig these 'loose grid-ends, the manual contact with the gr1d W1res results in an" uniawoidable percent f contamination of the grld surface which contamination may cause wlde 'diverg6ricesbetweri the chara.cteristics 01 the tubes into which the grids are assembled. 4 Accordirxgly it-is another object of this Invention to provide a device which automatioally trims the loose en ds'of wire-wound grid electrodes s as to reduce to a mlnimum the percent of Waste wire and to avoid the contamir nation and other undesirable efiects incldenta.l to the handling of the grids during the manual trimming operation.

'A.feature of the invention relates to a device 55 whereby the 1oose ends of a, grid electrode wire In these may be accurately trimmed wlthout affecting the usual grid side-rod.

Another fea.ture relates to a method 01 fusing the 1oose ends of a wire-woui1d grid.

A further fea.ture relates to an automatic de- 5 vice for trimming the loose ends of a. wirewound grid, which device may be rea.dily applled to a so-called continuous grid-strip wlnding machine.

A still further feature relates to the novel organization, arrangement a.nd relative location of parts which go to make up an efliclent and accurate grid-electrode trimmi ng device.

Other features and advantages not specifleally enumerated will be apparent fter a consideration of the following descrlptions and the appended claims.

While the invention will be described herein as applied 139 certain wellknown typ s of grid winding machines, it will be understood that this 1s done merely for explanatory purposes and notby way of limitation and furthermore since these grid-windlng machines are wellknown in the art the drawing herein represents the mechanism of such machines in diagrammatlc form o nl y. In the drawing,

Fig. 1 shows in diagrammatic plane view the invention as applled to a, continuous grid-strip winding machine. Y

Fig. 2 is a diagrammatic elevatlonal view oI part of the mechanism-of Fig. 1.

Fig. 3 is a. diagrammatic end view of the mechanism shown in Figs. 1 and 2.

F 'ig.- 4 is an enlarged view of part cf 'a. grldstrip showing the points at whlch the uniastened turn of the grld wire 1s cut accordlng tq the invention. 1 J L Fig. 5 shows a. aectlon 0Lgrid-strip wound in one known manner.

Rei'erring to'the dra.wing the numeral I rep- 40 resents a. suitable'base up0n which are supported wlre turns, and suitable mechanlsm is 'provided to peen, or swage the notched slde-rod so as to hold the turns of the flne wire firmly in place i n the said notches. When the requisite number of turns have been wound the Ieeding mechanism may advance the side-rods so as to increase the pitch of the next turn as indlcated in Fig. 5. The purpose of this skip4urn is to provide the operative with a suflicient length of Ioose wire so tha.t the grid section may be handied and trimmed by band. In another type o! grid Wind- Ing machine instead of producing the skip-turn for this purpose, the grld is wound with uniform pitch except that at regular intervals one o1 more turns a.re left unfastened. With this lai;ter type of machine, in order that the loose ends may be trimmed it is necessary for the operative to unwind the unfastened turns prlor to trimming the same. In accordance with the present lnventlon elther met h0d of winding may be employed, prei- 'erably however the mechanism 2 Is arranged to wind the flne wire 5 with uniform pitch as shown in Fig. 2 and at regular intervals the pe.ening or swagmg is omitted-from a single turn as indi-- cated by the numeral 8 in Fig. 4 and by suitable mechanism about to be descrlbed the flne wire 5 is electrically cut at the points marked by the arrows. For this purpose the wound grid-strip 1s fed pa.st a pointed electrode 1 which Is Insulatingly1supporte'd onan arm 8 plvoted a1: the point 9 on a bra.cket III attached to base I, it being understood that the arbor in machine 2 which carries the side rods 3 anti 4 is rotated In the direction of the arrow (Fix. 3) at the same time that the gxid strip is being fed Iorwa.rdly Irom the ma'chine as indIcated. Arm II is provided with an extension II in which Is adjustably mounted the tension adjusting screw II which Is adapted to bear against a. stop II fastened to a support I5 rigidly mounte d on base I. A tension spring I6 has one end Ifastened to support I5 a.nd the ot-her end to arm II thus impelling the electrode I toward the grId-strip. 'I'he spe.cing between the pointed end ot electrode 'I und the grid-strip may be accurately regulated by the ad.- Justing screw I2. Preferably the electrode I is so mounted that when moved I;o cutting position II; is in registry with the part of the grid-strip marked by the arrows (Flg. 4) and when eurrent nasses, the lateral grid wire Is cut by a fusing operation as close as possible I:o the slde- IOd 3 but without this latter rod. In this counection II; should be noted tha.t the electrode I is so polnbed and is moved a.t such an angle tha.t lt flrstfuses the loose gricl tum at the polnt A in Iront of the side-rod 3 und subsequently tuses this turn at the point B in back o! the side-rod I.

In order that the electrode I may be operated in proper timed relation with respect; to the rate at which the grid-strip 'is -ted I rom thewindin8 maohine 2, there is provided a cum II amxed to a shai't III which may be driven In the proper timed relation Irom the main shattfl! which drives the winding machine 2, lt being anderstood thal: appropriate gea.ring a.n d bea.ring brackets are provid ed Ior shaft I8 aa Indicated by mmierals III, 2I. Afllxed t o base I is a pI-vot pin 23 on which Is mounted the pivoI; block 24 for vertical rotation about sald pin 23. Passing through block 24 is an arm 25 which ha.s fastened to one end the cum follower 26 adapted to ride on cam II. The opposite end of arm 25 is Connected by a link 21 bo the electrode support arm II. As will be seen the cum II is provided with two Iow sectors 28, 2,9, so that when the 1'ollower 2 is In these sectors'the electrdde I is advanced to cutting position a.s indicated by the arrows in Fig.

4. 'I'he speed o1 rota tion of cam II Is related so the speed o1 feeding of the grid-strip so that when the follower is in sector '28, the elecirode I is in alignment with the point A o! the unfastened grid wirre tum (see FIg. 4) and when the outting position is so timed'with the Ieedinm movement of the gricI-strip that the unfastened turn of the fine grid wire alone is out und during the remainder of the i'eeding movement the electrode I is mit of cutting relation with the gridstrip. It will also be understood ahoi; sinne the gricI-strip is wound so that successive unit;

lengths thereof have the grid wires Iastened, the

cam II maintains the electrode I out 01 cutting relation so long as the fastened turns are passing the cutting electrode. If desired a. pair of outting knives or rollers indicated by the numerals 3II, 3 I, may be mounted in such a. way thai:

as the trimmed unit lengths of the grid-strip are fed pasi; these cutters the side-rocls 3 and 4 a.re cut at the points C, D, thus producing finished wound grids of unit length with the flne gridwires acourately trimmed and with suflicient 1ength of sic ierods 3, I, left; to serve as attach- 1 ment Iugs or supports for the grid. In I;his couneotion II: will be understood of cdurse that the winding unit 2 may be so arranged that two or more turns of the grid wire are lefI: unfastened.

und the cam II may be correspondingiy designed 1 to trim only these loose turns, thus allowing a greater length of exposed side-rod Ior grid supporting purposes. It will also be obvlous that instead o! employing only one cuttlng electrode, a pa.ir of aligned cuttsing electrodes may be employed so that the grid-wire may be trimmed adjacent both side rods. Thus in connection with the type of grid-strip shown in Fig. 5 where all the grid turns a.re fasteiied to thesIde-rods 3, 4, a Set of 'three cutting electrodes slmilar to electrode I ma.y be insulatingly mounted on the arm 8 so that one electrode cuts the grld wire a.t

point E, the second electrode a.t point F, and the third electrode at point G thus completely trimming the skip-turn" between adjaceni; unit lengths o! the grId-strip.

' In accordance with the present Invention it is preferred to aflfect the trimming o! the ioose grid turns by electrical means. Thus as shown In Fix. 1 the{electrode I Is connected by a. conductor 32 to one terminal of a suitable souroe o1 current .l3,

the opposite terminal of which is connected I:o the base I und thence oonduotively through the various parts described above, to the grid-strlp.

- Consequently when the electrode I is moved into cutting positlon a.s described, the flow-of eurren t at the point o1 contact with the grid wire causes a fusi ot1 o! the Iatter resulting in a, clean cut and without bur'ning or afl'ectlng the adjacent side-rod. Ifdesired the devices III a.nd II which are employed to cut the sl de-rocls may be replaced by electrodes similar I:o 'electrode 1 to afl'ect the outting of the sIde-rods electrically. In this case of cou.rsethe side-rod cutting electrodes will be moved into and out o1 cutting engagemeni: with the sIde-rods, by mechanism simi- Iar to that for moving electrode I.

In certain types o1 grids having relatively coarse wires or mesh, it may be impractical to move the pointed electrode I so that lt fuses the loose turn in back of the slde-rod as descrlbecl in connection wlth the fusing of the turn at the point B. In thls case two separate fuslng electrodes may be employed. Thus as lndlcated schematl'cally in Flg. 6, arm 8 whlch carrles the electrode 1 is linked' to another arm 35 which ls pivotally mounted at 36 so that when the arm 8 is operated by wise operated. Arm 35 will then carry a polnted electrode 31 simllar to electrode 1 but displaced the distance of one turn.- Wlth thls arrangement therefore. a single cam such as the cam I1 mta.y operate the mechanism so that electrode 1 fuses the loose grid tum (Flg. 4) at the point A in freut of the slde-rod 3 whlle slmultaneously therewlth. the polnted electrode 31 fuses the loose turn at. the point B in back of the slde rod. If desired the electrodes 31 and 1 may be adjustably mounted in thelr holders so as to accommo date the mechanlsm to difierent pltch grlds. It will also be obvious that lnstead of employlng a single cam' to operate the electrodes 1 and 31. two separate cams may be employed so that the said electrodes 1 and 31 niay be operate'd independently in any desired tlmed relation wlth respect to each ot.her.

Various 'changes and modiflcatlons may be made herein without departlng from the spirlt and scopei ot the inventlon.

What ls claimed is:

1. In a machine for trlmming cage-like grld electrodes of the type havlng a metal slde-rod and a fine wire wound therearound, a wlre severing eleetrode, means to feed a wound grld-strlp past said electrode and. to rotate sald grld strlp in front of said electrode me'ans for movlng sald electrode into severlng relatlon with sald grldstrip, and means for operatlng said severing means and said feedlng and rotatlng means in timed relat ion to each other.

2. In comblnatlon, a grld wlndin'g and feeding unit including means to rotate sald grld aboutits longitudinal axls, a grld wlre trimmlng unlt,

an electrode for severing the wound grld wlre at predetermlned spaced lntervals' and means. for oscillating said electrode into and out of severing relation with the grld wlre in tlmed relations to the sald feeding and rotating means.

3. In a devlce of the charaeter descrlbed a grid-strl p feeding unit lncludlng means to rotate said grid about its longitudinal axis, a grld wlre trimming unlt, an electrode for severing a grld wire adjacent lts support rod. a tlmlng cam for controllingthe operation of said severing means and means for operatlng said cam in tlmed. relation to the operation of sald feecllng and rotating means.

4. In a machine for trimmlng cage-llke grid elect rodes of the type comprislng a metal siclerod and a fine wire hellcally wound around and fastened to thesiderod, the comblnatlon of a severing electrode, xr'1eans to feed. the grid wlth its side-rod and flne*wlre past said electrode said severing electrode belng normally dlsposed away from said fine wire, and means to move sald electrode toward the fine w ire but at an angle tc the side-rod to sever the fine wire adjacent the side-rod and without afieetlng sald slde-rod.

5. In a machlne for trimmlng cage-llke grld electrodes f the type cornprislng a metal slde-rod and a fine wire helically wound around and fastened to the side-rod, the comblnatlon of a pointed cutting electrode, means to feed a. grld with the slde-rod and fine wlre past sald cutting the llnk 21 the arm 35 ls l1ke.

electrode, a source of current havlng one termlnal connected to the grld and the other terminal connected to said electrode, and means to move sald electrode toward the fine wlre to strike an arc between the polnted end of the electrode and the fine wlre only.

6. In a machlne for trimmlng cage-like grid electrodes of the type comprising a metal siderod and a fine wlre helically wound and fastened 1:0 sald. slde-rod, the comblnation of a trimming electrode means to rotate the grid around its longitudinal axis and to feed the grld longitudinally past the tri mming electrode, sald grld having at least one turn of the fine wire unfastened, means to move the trlmming eleetrode toward said fine wlre, the last-mentioned means bein automatlcally operated in timed relation to sald f eecllng and rotatlngmeans so that the trimming .electrode flrst trlms the end of the unfastened turn in tront ot the side-rod and then trims the end cf the unfastened turn on the rear of the side-rod.

' '1. In a. machlne for trimmlng cage-llke grld electrodes of the type comprislng a metal slde-rod arxd a fine wlre helically wound around and fastened to the side-rod; the combinatlon of a pointed trlmmlng electrode, means for formlng and f6edlng a grld strlp past sald trimming elec- 'trode said strip havlng at least one turn unfastened to the sicle-rod, means for movlng said trimm1ng electro'de lnto and out of arc formlng relatlon with one end of sald unfastened turn means to rotate the grld strlp to bring the other end of said unfasten ed turn into am forming relatlon with sald trlmming electrode, and means fqr malntalnlng 'sald electrode away from said 'grid strip when the latter ls rotating 8. In a machine of the character described, the comblnation cf a unit for winding and feeding longitudlnally a cage-llke grld in the form of a fine wire hellcally wound around a metal side-rod, a unlt for severlng the fine wire at predetermined intervals lncludlng a pointed arc-producing electrode, and means f or automatically operating both saldu'nlts in timed relation so that one side of the grid strip is first presented to said pointed elec trode, andthen the other side of the grld strlp is presented to salrl polnted electrode.

' 9. In a machlne for trimmlng cage-like grid electrodes of the type com'prising a rigid metal side-rod and a plurality of fine lateral wires bent\ around. sald slde-rod, a palr of polnted electrodes,

means for fee;ding a grld strlp past sald electrodegs, one of sald electrodes being dlsposed With lts polnt adjacent the lateral wlres on one side of the grld strip, and the other of said electrodes being disposed with its point adjanent the lateral wiresmn the other side oi the grid strip, and means for moving sald pointed electrodes lnto and out; of arc-procluclng relatlon with sald lateral wires in tlmed relation to the ieeding movement ofthe grid strlp so that said pointed electrodesx strlke an arc to said lateral wlres closely adjacerlt the s ide-rocl but without afiectlng said side-rod.

10. A machine according to claim 9 in which certaln of the lateral wlres are fastened 190 the side-rod and other lateral wires are unfastened, and the movement oi the pointed electro des ls timed so that an arc is produced only when the ends of the unfastened lateral wires are in reglstry with the said pointed electrodes. A

. 11. In a machinefor manui'acturing radio tube electrodes ofthe cage-llke type, me'ans for windlng a fine wire around a pair of metal side-rods wlth some cf the turns fastened to the side-rocls and other turns unfastened, means for severlng the unfa.stened turns comprislng a pointed arcproducing electr'ode, a member in which said. electrode is adjusta.bly mounted, a cam for uperating seid member, and. means for operating said cam in timed r elation'to the windi ng of sa.id fine W1're so that saicl pointed electrode is moved to severing position only when the ends of the unfastened turns are in registry therewith.

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