US2592549A - Anode structure for electron discharge devices - Google Patents

Description

April 15, 1952 s. o. EKSTRAND Erm. 2,592,549

ANODE ySTRUCTURE FOR ELECTRON DISCHARGE DEVICES Filed Aug. :3, 1949 5 Sheets-Sheet l ATTORNEY April 15, 1952 s. o. EKSTRAND ETAL 2,592,549

ANODE STRUCTURE FOR ELECTRON DISCHARGE DEVICES F'ledAug. 5, 1949 3 Sheets-Sheet 2 FORM PLATE BLANK WELD TWO ELAN/(S TOGETHER HYDROGEN HEA T TREATMENT BUMP/NG OPERA T/ON COAT/NG TREATMENT WE r S. fm?

V ORS VLM/Vm ATTORNEY April 15, 1952 s. o. EKSTRAND ETAL 2,592,549

ANODE STRUCTURE FOB ELECTRON DISCHARGE DEVICES Filed Aug. 3, 1949 -3 Sheets-Sheet 5 ATTORNEY Patented pr. 15, 1952 2,592,549 AonE s'ritiiointit injcnnctin DISCHARGE DEVICES Ssmite lo. icksnaimi, Bethlehem, and victor L. Ronci, Zionsville, Pa., as'signors to Belli-elepho'ne Laboratories, Incorporated, New York, N;Y.-, a corporation of New -York Atpiiatitn-Agusts,1949, serial No. 168,356 '1o citons. (chars-maze) example, 'close finterelectrode spacing, Specially siiiall's'pac'ing between grid and anode, leads to sniall voltage drop-and sharp 'cutoohaacterisn'ds. 'The realization o'ff 'smallspannen"1f-mw-V ever, entails manifold practical difficulties. Spe cinauy, itis qifult not only' to obtain 'accurate initialv small electrodel s'pacins vlout also to'rfnainq tain s uch fspacings' duringfoperation of thedevice. Frther, the realization 'of unforr'nitynoi product'in quantity manufacture of electron dis'- chargedeviceshavingclosely adjacent electrodes involvesiobvious complexities. The general `prolo- 1on1y involved may be* appreciated vvvl'il-:n itisv noted that in particular triodes having a-no'n'al g'rdtoanode 'spacing ofthe order f 0.0085'`inch the permissible 'tolerances in this spacing Y-to ineet p fesiitd operatirig'requimts arefofftneordr of A$01.001' inch. Y Y

vOne general 'object of'tlis invention' is -toiine prove-the structure-and perfrniance-characteristicsof electron` discharge devices l`and especially ofsuchdevices itali/ingv very closely spaced electrodes. MrespecicallS/,jobjects of 'this' iriv'nfv toiialfto facilitatey thattairnent of proscribed s'nall interelect'rode 'spaoingisl to 'eipedite 'the fabrication of devices li'iiludii'g Ver? Closely spaced lectrodes, to I'ni'niiniz'e variaton'sln'th interelectrode spacings drin opzeratoiif the devices, and to enhance unforrnity'oi pr'oductin the quantity manufacture of sch devices.

Inaccordance `With one rfezftture of kthis invention, an anode for'"elect`ron discharg'edevices" of the Atype having portions orse'ctions onfvopiosite sides vof ano/ther electrode; Such `as acatlodeV or g'ridygvis constructeur-if two parano plate-'sections having spaced 'er'nbossinnts the eiiljos'slnts on the tvlfoSectionsy loei'gv joined inV abutting relation tor-nx the-'spacing lietween'the sections.

yIn accordance withanother feature of this 'invention, the'anode sections are povided'with extensions*or-ears'constructed'and arranged so that theymaybe readily associatedwith spacer inem'- b'ers, such as insulatingdis'cs, to vinou'ntandposition the anode in prescribedrelatoto 'other electrodes-arid! 'to mainte-m the ande'po'sition dtiiiifpe'ftinof the device.

2 `In accordance with a further" featrefoflvfiis invention the anode, after assembly, is 'Ht treated to relieve stressesV resulting from the-'joinl'igf th anode Sections, Whl'by 'llle''e"{SC'/Y maintain their proper relationship. I

InA accordance With a still f'th'er fatui'fof invention the l anod'esections ai'ejslqjotedA to -a Vlo'l'ilfriping operation tofinsure uniformity'vf spacing and parallelism between theplatescl-f tions'.

These and other vdesilalle"features incbi-vl porated in one illustrative embodimentlo 'thli1 invention l'a twin triodein vvh-iclitl'ie twinelectrode elements are iolntd in parallel iel'atifoi"ivv attached 'to 'a vertical lediiifi Wire in -tll stein. The athdis'are separato@ connected-fte' other lead-in wires in westen. The sgnasjafr'e v'vuno side'rdds'of theswdg'edrtvne and oie'- wi'ifdinfgs' or laterale trentamila relation-to the greater dimensions of the cathode surface circular y,emtos"smartsYai15aentme 31o it edges. The Y einboss 'ents 'innneafcheprlaf er-bos'sieijits ofthe other pia-fett iiithithe'y j manly ""idd. The amies also 'prat/idea with Vdiifer'eiit sized vpairs earsf atfech ."czvifrerVV to-lock theanodes in tlieniica spacers; the laie ears mounting Ythe anodesfrom the spacers Vand is then coated with a black-body gas-absorbing coating.

A complete understanding of these and other desirable features of this invention may be gained from consideration of the following detailed description and the accompanying drawings, in which:

Fig. 1 is an elevational View of a twin triode electron discharge device embodying an anode structure illustrative of this invention, a portion of the enclosing vessel being broken away to show the internal assembly;

Fig. 2 is a side view in elevation of the elements as mounted in the stem of the device shown in Fig. 1;

Fig. 3 is a sectional view of the device taken along line 3-3 of Fig. 1;

Fig. 4 is an elevational view of an anode section illustrative of one embodiment of this invention;

Fig. 4A is a sectional view along line 4A-4A of Fig, 4;

Fig. 5A is an end view of a die used in the preparation of the anode structure in accordance with this invention;

Fig. 5B is a side view of the die of Fig. 5A;

p Fig. 6 is a perspective view of one die member of Fig. 5, showing the anode structure mounted on the mandrel;

Fig. 1 is a diagram illustrating the steps to be taken in the preparation of the anode structure; and

Fig. 8 is a sectional view of one triode structure taken along line 8-8 of Fig. 2.

Referring to the drawing, the electrode assembly is mounted in an enclosing vessel I0 which is sealed in a base I I, provided with a plurality of terminal pins I2 mounted in parallel relation in a circle. The electrode unit, which for purposes of illustration is shown as a twin triode, comprises a pair of parallelly arranged groups of electrodes, the similar elements of each group being identified by the same numeral. The anode of the triode is composed of parallel plates I3 and I4, joined together by embossments I5, and encompassing cathode I6, a helical grid I1 which is wound on support rods I8, and a cathode heater I9, best seen in Fig. 8. The electrodes are mounted between insulating spacer discs 23 and 24 and are connected through the stem 20 to the pins I2 by appropriate leads. Thus the two grids I1 are independently connected to two pins I2 by the leads 25 attached each to a grid rod I8, and the cathodes I6 are connected to pins I2 by two leads 26, the leads being composed of a ribbon portion attached to the electrode and a wire portion attached to the pin, the two portions being joined together as by welding. The heater elements I9 are connected to two leads 28 by cross wires 21, the two heater elements thus being connected in parallel. The insulating discs 23 and 24 are supported in spaced relation by a plurality of rigid posts 32, 33, 34 and 35, two of which extend from the inwardly projecting stem 20. `The insulating discs are attached to the posts as by eyelets 36. A short lead 31 connects one anode to the post 32 and another lead 31 the other anode to post 35, the two posts extending into the stem 20 and being in turn connected to appropriate pins I2. Thus the cathodes, grids and anodes are individually connected externally through the pins I2 for applying suitable potentials to the various electrodes.

'I he cathode I6, as shown best in Fig. 8, comprises a rectangular sleeve. as of nickel, which is coated on the outside with electroemissive material, such as a nely divided barium-strontiumcalcium carbonate in amyl acetate solution of nitrocellulose plasticized with butyl Cellosolve. The grids I1 may be of the swedge type with laterals formed of molybdenum wire and goldplated to reduce emission from the grids. The spacer discs 22 and 23 may be of mica.

An insulation disc 40, which may also be of mica, is supported above the electrode assemblies by the posts 32, 33, 34, and 35, to which it is attached by eyelets 4I. Side strips 42, which may also be of mica, are attached to the disc 40 and held in position by ears 43 evenly spaced around the periphery of the 4disc 4i). The disc 40 and side strips 43 serve to prevent vibration of the top end of the electrode assembly.

A getter wire 44 is mounted by a getter support assembly 45 attached to one of the posts, such as 32.

The anode sections I3 and I4, as shown in Fig. 4, are provided with diierent sized pairs of ears 46 and 41 to lock the anodes in the spacer discs 23 and 24. The large ears 43 provide the rigid mounting of the plates and one of the narrow ears 41 is connected to lead 31 to provide the connection to the post and thus the pin I2. While only one ear 41 is used for each anode the plates are stamped with the ears at all corners to simplify the assembly and thereby avoid selection of parts for the fabrication of the anodes. The anode sections are also formed with end iianges 53 between the ears 46 at both ends of the section.

The various electrodes are supported in iixed position by the spacer discs 23 and 24, as best seen in Fig. 3 with reference to disc 23. The disc is provided with apertures 48 through which the narrow ears 41 extend and with apertures 49 and 50 through which the larger earsy 46 extend. The apertures 49 are slightly larger than the ears 46 so that the ears float in them, but the apertures 50 are of almost the same width as the ears 46 so that the ears are tightly held thereby. A short section of the ears 4G is flat and parallel to the plane of the anode section to accomplish location in the disc 23. The remaining parts of the ears 46 are bent slightly to facilitate entrance into the respective slots in the disc 23 and to clearly dene the ear sections in which parallelism must be maintained. Apertures -5I are provided in the disc 23 through which the cathode sleeve I6 closely ts, the sleeve being formed with embossments 52, best seen in Fig. 2, directly beneath the disc 23 and above the disc 24, to hold the cathode firmly in position. Other apertures are provided in the disc members through which' the posts and rods I8 extend.

In the construction of the anode, each anode section I3 and I4 is first blanked and formed in a press, the embossments I5, ears 45 and 41, and end flanges 53 being formed with the sections. The sections are then placed in a welding jig in which the sections can be rapidly aligned. ri'he embossments I5 on section I3 are then welded to the embossments on section I4; all six welds may be made at one time, or singly if preferred. The welded assembly is then heat treated in a hydrogen atmosphere to relieve all strains from the welding operation and the original forming operation. It has been found advantageous to heat the assembly at around 1000u C. for about 10 to 15 minutes. y

.lt has also been found advantageous that the assembly in this stage have a spacing between the two'sections I 3 and I4l which is slightly larger than Vthat required by the tube geometry. -It has been found that the different assemblies after the heat treatment have larger variations in the spacing between sections from one assembly'to the 'next than'can be tolerated. In order-to insure uniformity ofspacing inthe assembliesand parallelism between the sections I`='3 and I4 -ea'ch :assembly is'subjectto a bumping operation in a die such as shown inFigs. 5' and 6.

The bumping die shown in Figs. 5 and 6 comprises an upper diemeinber 51 and a lower die member 58 the die faces of which are hardened, ground, and parallel. Both die members have two parallel slots 59facross their width'and four shorter slots 50 extending lengthwise fromthes'e parallel slots to the edges of the die. A tongue or mandrel 6I, which is'hardened and ground with-parallel faces, is hinged to an end portion 62 of thelow'er die member 58,' asjon a pivot' rod 'extending through apertures Ifl in 'the end portion-62. The die members may be held-in the pressl by screws extending into the threaded apertures 65 in the upper member 5'I and 5S in the lower member 58.

The assembled anode is iirst inserted on the tongue 6i, as shown in FigQ. When the tongue BI is lowered so that the anode section IIIv isdirectly on top of the face of the lower die 58, the end flanges 53 iit into the slots 59 and the ears 4S into the slots 50. The end flanges 53 thus serve to position the assembly in the die. The upper die member is then brought down pressing the anode assembly between the two die faces.

This operation results in the plate being squeezed to an inside dimension equivalent to the tongue thickness plus spring back. Since the only support existing between the plate sections is that of the six columns made up of the welded bosses, the plate is brought to proper size by crushing these columns. Thus the iinished bumped plate assembly is still practically free of stress in the flat areas of the plate, which were not aifected by this bumping operation, and hence does not lose the minor axis dimensional accuracy in subsequent operations.

When the assembly is thus brought to proper size it is then treated with a black-body and gas absorbing coating, such as a zirconium hydride.

These steps in the preparation of an anode assembly in accordance with this invention are diagrammed in Fig. 7, the steps being the making of the form plate blank and the bending of the iianges 53 and ears 45, the joining of the two sections I 3 and I4 together by welding the embossments I5 together, the hydrogen treatment of the welded assembly to relieve stress, the bumping operation in a bumping die to accurately form the anode assembly, and the coating treated onto the anode assembly.

When the anode is assembled in the tube the dimensions between it and the other electrodes are held to close tolerances by the design of the ears 4S and the apertures 49 and 50. Motion of the anode assembly perpendicular` to the plane of the major axis of the cathode I6 is restricted by the inside of ears 46 inserted in the apertures 49, 5B. Motion parallel to the cathodes major axis is restricted by the ears 46 and apertures 50, these being formedwith a close tolerance so that the ears 46 have an interference nt in the discs 23 and 24 while the ears 46 located in apertures 49 are allowed to oat in the apertures 49 in this direction. This oating 6 of the Y'ears 'a'.tV one end ofV4 the anode assembly permits of wider piece part tolerances lin the dimensions between the ears.

Reference'is made to our divisional-applicationf' Serial No. 227,214, filed May 19,*1951 wherein certain related features of this invention are claimed.

Itis to be understood that' the'above-described arrangements are illustrati-ve of the application of the principles ofthe invention. vrNumerous other arrangements maybe devised by v`those skilled in 'the art without departing fro'mthe spirit and scope of the invention.

What' is claimedis:

l. An lectrodeassembl'y' for electron discharge devices comprising a pair of plate sectionshaving "inwardly projecting r embossments, vthe fembossments ofthe first pla-te being :inlabutti'ng aligned relation `with the embossments f of' 'the' second'plate and secured thereto.

2. `A'n "electrode assembly for electron 'fdischarge devices comprising a vpair-of platesectionshaving spaced' inwardly projecting embossments adjacent parallel edges,fsaidembossments being in abutting aligned relation an'dlocally-A welded tofprovide accurate spacing betwee'nsaid sections.

*3. nna-node assembly for electron discharge devicesl comprisinga pair of flat plate sections having inwardly projecting embossments adjacent pa'rallel edges, the embossments of the rst plate being in abutting relation with the embossments of the second plate and secured thereto to provide accurate spacing between the sections.

4. An anode assembly for electron discharge devices comprising a pair of flat plate sections having spaced inwardly projecting embossments adjacent parallel edges, the embossments of the rst plate being in abutting aligned relation with the embossments of the second plate and locally welded thereto to provide accurate spacing between said sections.

5. In an electron discharge device, a cathode and an anode assembly surrounding said cathode, said assembly comprising a pair of at plate sections having spaced inwardly projecting embossments removed from said cathode, the embossments of the rst plate being in abutting aligned relation with the embossments of the second plate and secured thereto.

6. In an electron discharge device. a cathode having two oppositely directed emitting surfaces, a grid portion adjacent each emitting surface, and an anode assembly, said assembly comprising a pair of plate sections each opposite one of said emitting surfaces, said plate sections having spaced inwardly projecting embossments adjacent parallel edges thereof, the embossments of one plate being in abutting aligned relation with the embossments of the other plate and secured thereto to provide accurate spacing between said sections.

7. In an electron discharge device a cathode and an anode assembly. said assembly comprising two flat plate sections, one on each side of said cathode, said plate sections having inwardly projecting embossments, the embossments of the one plate being in abutting relation with the embossments of the other plate and secured thereto, said plate sections having ears at each corner thereof, and insulating support means cooperating with said ears and said cathode to support said anode assembly and cathode in spaced relation to each other.

8. In an electron discharge device a cathode, grid support rods adjacent said cathode, a grid wound on said rods surrounding said cathode, an anode assembly encompassing said grid and cathode, said assembly comprising a pair of plate sections having inwardly projecting embossments, said embossments being in abutting relationship and secured together, ears extending from each of said plate sections parallel to said support rods, and insulating support means cooperating with said rods, said cathode and said ears to position said cathode, grid and anode assembly in spaced relation to each other.

9. In van electron discharge device, a sleeve cathode having embossments thereon adjacent its ends, grid support rods adjacent said cathode, a grid wound on said rods surrounding said cathode, an anode assembly encompassing said grid and said cathode, said assembly comprising a pair of flat plate sections having spaced inwardly projecting embossments adjacent parallel edges, the embossments of the first plate being in abutting aligned relation with the embossments of the second plate and welded thereto, a pair of ears extending from each corner of said plate sections parallel to said support rods, a pair of insulating discs cooperating with said rods, said cathode embossments, and one of said ears at each corner to position said cathode, said grid, and said anode assembly in spaced .relation to each other, and connections from said cathode, said rods, and one of the other of said ears to leads extending external to said device.

10. An electron discharge device in accordance with claim 9, wherein said insulating discs have apertures therein and wherein at least one of said rst ears tightly fits into one of said apertures and the other of said rst ears floats in the other of said apertures.

STURE O. EKSTRAND. VICTOR L. RONCI.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,514,898 Geisey Nov. l1, 1924 1,919,984 Murphy July 25, 1933 2,075,639 Castle Mar. 30, 1937 2,464,272 Suesholtz et al. Mar. 15, 1949 2,476,940 Wood July 19, 1949 FOREIGN PATENTS Number Country Date 262,806 Great Britain Mar. 31, 1927

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