Патент USA US2411184код для вставки
Nov. 19, 1946. J, E, BEGGS 4 2,411,184 FABRICATION 0F DISCHARGE DEVICES His Attorney. Nov, 19, 1946. J. E. BEGGS ‘ 2,411,184 FABRICATION 0F DISQHARGE DEVICES Fiied July 2, 1942 Y \\\\\\\\\\\\\\ ' /30 2 Sheets-Sheet 2 « Patented Nov. 19,~ 1946 2,411,184 UNITED STATES PATENT OFFICE 2,411,184 ì FABRICATION oF DISCHARGE DEVICES ‘James E. Boggs, Scotia, N. Y., assîgnor to General ` `Electric Company, a corporation of New York ‘ Application July 2, 1942, Serial No. 449,391 15 Claims. (Cl. Z50-27.5) l 2 . This is a continuation-impart of my copend ing application, Serial No. 436,633, filed March `28, 1941, and assigned to the General Electric Company, a corporation of New York. The present invention relates to the fabrica tion of electronic discharge devices and more par ticularly to a process for obtaining a precise spac ing of the electrodes of such devices. In connection with vacuum tubes for use in tional steps in the process of completing the fab rlcation of the tube of Fig. 1~; Figs. 6 and 'l show an alternative method of procedure accordingto the invention; Fig. 8 illustrates the application of the invention to a form of device somewhat dif ferent from that illustrated in Fig. 1; Figs. 9 and 10 are enlarged detail views which illustrate various aspects of the structure of Fig. 8; Fig. 11 is a sectional view of a diode of a type which the ultra-high frequency range it is important 10 may be produced in accordance with the inven that the interelectrode distances be uniformly tion, and Fig. l2 shows an intermediate step in 4maintained from tube to tube with a deviation not materially in excess of a fraction of a mil. Any deviation greater than this, especially with reference to the spacing between the cathode and grid electrodes, results in inconsistent and un predictable operating characteristics and is, therefore, highly undesirable. It is an object of the present invention to pro vide a method of tube fabrication by which tol erances as close as those specified can be readily maintained. . One aspect of the invention which is important in the attainment of the foregoing object involves the fabrication of the tube of Fig. 11. Referring particularlyto Fig. l the discharge tube there illustrated includes a series of three circular metal members I Il, II and I2 which are arranged in spaced relation and which are mu tually separated by vitreous `(e. g'. glass) cylinders I3 and I4 sealed between them. Both the metal members ID to I2 and the cylinders I3 and I4 ‘ are of progressively decreasing diameter from one end of the tube to the other so that the tube as a whole has a step-wise coniiguration. ' The metallic part I2 includes a planar portion I8 having a central opening I 9 and a circular rim making at least one of the electrodes employed of 25 2U which extends away from the main body of deformable construction, installing the electrode in approximately its desired location in the tube structure, and thereafter deforming the electrode in situ to bring its active part more precisely into the desired relationship with the other electrodes 30 the discharge enclosure. Within the opening I9 there is provided a cathode structure which in cludes a supporting part 24 and an active part consisting of a metal disk 21, a cylindrical sleeve of the tube. 29 Which depends from the disk. The disk is preferably coated on its upper'surface with an activating coating such as a layer of barium and ` Another important feature consists in the use of an arrangement and procedure by which ad justment of the deformable electrode serves con 28 secured to the disk 21 and a flanged sleeve Strontium’carbonates, and a ñlamentary heater currently to establish the proper relationship be 35 32 arranged within the cathode structure serves tween the remaining electrodes of the tube. ' to maintain the disk at a temperature of ther A still further feature, which is ancillary to mionic emission. In the use of the device, the those specified above, comprises the use of a heat developed by the filament 32 is conveyed to multipart cathode construction of such nature the emissive disk 21 both by direct radiation and that relative adjustment of the respective parts 40 by conduction through the sleeve 2g. 'I'he sleeve affords ‘an effective means for bringing the active 29 serves the further function of minimizing ra component of the cathode into precisely the diation of heat to the other parts of the cathode proper correlation with the other electrodes. ` The features which I desire to protect herein ` The part 28, by which the emissive disk 21 is are pointed out in the appended claims. The in 45 directly supported, is preferably constituted of vention itself, together with further objects and a thin foil of a metal of low thermal conductivity ‘advantages thereof may best be understood by such, for example, as a nickel-iron-cobalt alloy reference to the following description taken in (Fernico) ._ Because of the relatively limited heat connection with the accompanying drawings in conduction path‘j provided by the foil, Whichmay `which Fig. l represents in section a three-ele 50 be on the order of a few tenths of a mil in thick ment discharge tubeßof a type which may suit ness, the loss of heatf from the disk 21 to the structure. ably;Y be constructed in accordance with the in vention; Figs. 2 and 3 represent successive steps ` l ` other part of the cathode structure is relatively slight, and eflicient operation‘of .the cathode is in the process 4ofi’abricating a tube such as that assured. The part 28 is of such dimensions that illustrated in Fig. 1; Figs. 4 and 5 represent op 55 it may slide over the part 24,‘being prevented from 2,411,184 3 welded connection to it. 4 surfaces shall be perfectly clean and resistant to corrosion. moving with respect to that part, however, by a (The cathode structure The disk II which is sealed to the upper ex tremity of the cylinder I4 is provided with a bination of the heat shield 29 and the part 23 which provides high resistance to heat flow, is DI central opening 5S and supports a mesh grid 51 just specified, including particularly the com more fully described and is claimed in my co covering this opening, the grid being spaced only pending application Serial No. 453,158, filed a few mils from the active surface of the cathode disk l21. Above the grid and in cooperative relation with respect to the grid ’and cathode, August 1, 1942, and assigned to the General Elec tric Company, a corporation of New York.) For the purpose of supporting the cathode structure, a Series of relatively rigid conductors 38 are attached to the lower surface of va. circu i there is supported an anode in the form of a This extends through an solid cylinder 6B. _opening formed centrally in the disk I2 and con lar flange 25 formed on the part 24. The part 25 is arranged in face to face relation with the lower surface of the partlß but is maintained at a fixed spacing with respect to this part by the nects above the disk with a cylindrical terminal 6I which, as shown, is of smaller diameter than interposition of a sheet or layer of a dielectric produced between the terminal 6I and the disk substance 42 consisting, for example, of mica or other inorganic insulating material. As a result of this arrangement the cathode structureA is in sulated from the part I2 with respect to unidirec tional currents while being effectively connected to -it (e. g. through the capacity between the op posed surfaces of the parts I8 and 25) as far as high frequency currents are concerned. As a consequence, the part I2 is adapted to serve as a high frequency terminal for the cathode the disk Iil, although of larger diameter than the hole formed in the disk. A fused metal joint IIJ, as indicated at 62 renders this end of the tube vacuum-tight and completes the enclosure of the device. ' In connection with a tube such as that de scribed, it is extremely important that the spac ing established between the various electrodes and especially the spacing between the cathode disk 21 and the grid 51, be maintained within very close tolerances and be substantially< in variable from tube to tube. In order to fulfill this condition in a manner which is consistent ' structure. -Unidirectional potential may be supplied to with the requirements of quantity production the cathode and heating current may be sup- t plied to the filament 32 by means of the con ductors 38 and additional Vconductors 43. con methods, the present invention makes use of a procedure such as is illustrated in Figs. 2 and 3. In the first of these ñgures there are shown nected-to the terminals of the ñlament. In the certain tube parts which correspond to various illustrated ductors are sealed through a metallic closure . parts illustrated in Fig. 1 and which are similarly numbered. These include particularly the en member 44 which is hermetically sealed by a soldered joint 415 to the lower edge of the cir cular rim 20. Individual glass-to-metal seals 41` corresponding in number to the lead-in con ductors, serve to maintain the conductors in in 40 the cathode parts 24 to 29. The parts IU to I4 and the grid 51 are already assembled in the relationship they are expected to occupy in the ñnished device. 'I‘hese parts, arrangement, these various con closure-forming parts I0 to I4, the grid 51, and sulatingly spaced relation With'respect to the part 44. The externally extending extremities ’together of the lead-in conductors are soldered into tubu lar contact prongs 52, and these in turn are sup ported in an insulating adaptor 53 which is suit posed between the cathode disk 21 and the grid ably secured in engagement with the closure 'member 44. VA centering pin 55 which depends from the kadaptor 53 serves to facilitate the orien tation of the tube in a cooperating socket. , The class cylinder I4 is sealed to the upper , surface of the planar wall part I8 in a region .surrounding the cathode structure, the joint be tween these parts being vacuum-tight. In order to facilitate the production of a joint of this kind it is expedient to -form the part I2 as well as ' >the disks I0 and II of iron and to use for the cylinders I3 and' i4 a glass which is capable of with the incompletely assembled cathode structure and a spacing cap "B9 inter 51, are mounted upon a fabricating jig having an outer cylinder 10 which bears upon the cathode part 25 and a retractable plunger 1I which engages the lower extremity of the part 29. (At Vthis point no joint exists between the cathode parts 24 and 28, so that relative motion of these parts is possible.) A spring 13 located within the’interior of the jig structure tends to press the plunger 1I upwardly while a set screw 14 affords a convenient means for locking the plunger in a. particular location with respect t0 the body of the jig. The jig as a whole, and the parts which it carries are supported upon a fixed arm 16 extending outwardly from a bench 11V or other immovable working surface. . being sealed to iron, such glasses being described, In place of the anode 60 referred to in conf for example, inV Hull and Navias Patent No. 2,272,747, granted February 10, 1942. To make 60 nection with Fig. 1 the upper part of the tube contains a'location-determining agency 80 which VJthe sealing process easier, the various metallic is in substantially the same form as the anode parts in question are preliminarily coat-ed with 60 but'which differs in length from the anode copper, which has they further effect of increas by an amount corresponding to the spacing de ing the’ surface conductivity of these members with respect to high frequency currents. The 65 sired to exist between the active surface of the anode and the active portion of the , grid 5,1. The part 8i) is provided at its upper end with an 'enlarged cap 82 which determines the distance this oxide before putting .inv place the cathode which the part BIJ> can project ’ intoï Athe structure and Ythe closure member 44 upon which the cathode ` structure is mounted. 70 tube enclosure. The cap 82-has a still larger part 82’ whichV is engaged by' a recess formed in ’As a further preliminary" to evacuation of the _copper is to some extent oxidized during the sealing >procedure and it is desirable to remove device and sealing in of the closure Amember it .has been found helpfulin some -cases to silver a movable arm 84, and at its opposite ,end the or gold plate the internal andr external surfaces ,a plunger 85 which is attached to anjoperator arm 34 is secured -to the upper extremity of of the parts I0", II and I2 -to assure that these 75 controlled pedal or actuator indicated at 81. 2,411,184 The `pedal 81 acts against‘a spring 88 so that the plunger 815 is normally biased in the upward direction, but when pressure is applied to the pedal, -the plunger and consequently the part 80 are :moved downwardly. Assuming the set screw 'I4 to be in a retracted position, the part 80 acting on the grid 51 will overcome the action of the spring ‘I3 and will move the discharge enclosure downwardly until the part i8`comes to rest upon the upper surface of the insulator 42. When this condition is Vattained the sup parts of the cathode structure together, some slight displacement of these parts may occur in spite of the fact that they are‘retained very close ly in their proper relationship‘by the jig elements 10 and 7l. If any displacement of this kindlhap-` pens, it can be readily rectified by replacingythe cathode structure in the lining up assembly shown in Figs. 2 and 3. If this is done and the part 80 is again forced downwardly into its lowest pos-_ sible position, it will reestablish the 'desired re iationship of the various elements. »In some cases it may be desirable to substitute for the element "it a similar element having a length a fewgmils reference tothe tube as a whole. Since further greater so that it is capable of producing a slight downward motion of the tube is impossible un 15 additional deformation of the >grid 5l. When der ‘the vcircumstances ‘ assumed, continued such a longer element is forced down into the tube porting part 24 of the cathode structure is in substantially its intended relationship with motion of the part 80 can occur only as a result of downward deformation of the grid 51 as in dicated in Fig. 3. ifA the lforce applied is suffi cient to cause such deformation to occur, the assembly it will obviously seat the grid firmly upon the spacer 69 even if some slight shrinking or- deformation of the cathode structurehas oc curred. If no such shrinkage exists, the slight additional displacement of the grid will be taken the capV 82 is seated upon the upper surface of up by a correspondingly slight deformation >or the disk It. If subsequently the part 80 is re compliance of the foil of which the cathode part placed by an anode which diiîers from it only 28 is constituted. It is assumed that‘the cath in being a: mils shorter, it is clear that a spacing ode parts 2e and 28 are welded in iixed relation of exactly :c mils will exist between the anode ship at this point so that relative displacement andthe deformed central portion of the grid 5l. between them is no longer possible, The details This then affords an extremely accurate method of this realigning step are indicated in Figs. 4`and of obtaining a desired spacing between the grid 5 in which the displacement between the"dotted and anode in a construction such as that illus 30 lines a and b represents the difference inv length tratedY in Fig. 1. In a particular case a spacing between the location determining agency ' 8i) of about 13"mils has been found appropriate. originally employed and theslightly longer ele To obtain an equally accurate spacing between ment 8d’ employed in the realigning‘proces's; the grid and the active part of the cathode struc Spot weids joining the cathode part 28' tothe ture, it is only necessary to make the cathode-grid part 2d are indicated at 95 in Fig. ` ` ` . spacer 69 of the proper dimensions. In general, After the assembly of the cathode parts and . it is found desirable to apply the activating coat the rechecking of the cathode to grid spacing has ing to the cathode disk [il after the cathode as been accomplished, the cathode filament 32 (Fig. sembly is completed so that the spacer E9 should l.) is inserted in its proper location and the cath part 8i) will eventually reach the point at which have a thickness equal to the desired cathode to 40 ode structure as a whole is mounted upon the grid spacing (say, 4 mils) plus one or two mils to closure member 44 (i. e. by means of the con-` take into account the expected thickness of the ductors 38 and d3). Finally the closure member subsequently deposited layer of activatingmate is soldered to the lower edge of the circular flange rial.` Eil by a mass of solder 45 as previously specified. ‘ With the spacer 69 in place, the upward pres - The flange 2i) is of such dimensions with relation sureof the spring 'i3 (Fig. 2) serves to maintain to the length of the `conductors Sethat it does not the spacer clamped between the grid and cathode seat upon the surface of the closure part 44 but surfaces as the grid is deformed downwardly and remains slightly spaced from it while the soldered thus holds a constant spacing between these sur Joint is being produced. This means that the faces. This spacingwill he retained even when 150A cathode part 25 can lbe forced firmly against the 'the ’part 80 moves to its lowest permitted posi insulating disk ¿i2 and' that the disk iny turn can I tion (i. e. the positionillustrated in Fig. 3). Ac be seated solidly upon the envelope part i8. Ác cordingly, if the cathode structure is frozen in cordingly, assurance is provided that the cathode the relationship which it then occupies, the` de structure as a whole occupies precisely the rela sired relationship between the cathode and the 55 tionship which it had during its preliminary' ad grid and anode elements will have beenestab justment (i. e. during the performance of the‘pro lished. ¿This “freezing” of the cathode parts can cedural steps illustrated> in Figs. 2 and 3.) be accomplished by adjusting the set screw 14 so In some Vcases itis desirable to omit the insu that it clamps the parts 7G and 'H in fixed spatial relationship and then removing these elements 60 lating disk «l2 and to solder thecathode part 25 directly to the envelope part I8. Where this is from the tube assembly together with the cathode parts which they respectively support. Without disturbing this arrangement, the cathode foil 28 done, the preliminary line-up procedure will be the same as that described in the foregoing eX cept thatthe part 25 will be seated against the may then be welded to the outer surface of the part 2d ‘so that no subsequent displacement be 65 part la during the deformation of the grid 5l. tween them is possible. The spacer 69 may then It is not necessary that the means employed to be 'removed and the cathode Vreinserted into the determine thespacing between the anode and the tube assembly with the certainty that its active grid 51 shall take the precise Aform represented in surface will occupy the desired relationship with Figs. 2 and 3. Alternatively, one may employ the respect to the grid 51. (The fact that the part 42` 70 anode` itself in connection with a spacer‘of ap abuts ñatly against the under surface of the part` propriate dimensions‘used in the manner of the 25lmakes it certain that the earlier disposition of spacer 69. Of course,.where such a spacer isern the cathode structure in the discharge enclosure ployed, it must be capableof attachmentto the lower extremity'of the anode andthe opening `It occasionally happens that in welding the 75 formed in the disk. i0 `must be of sufficientdiar'nef-k can be accurately reestablished.) 2,411,184 7 ter'to `permit the introduction through it of the the cathode so that it lies flat upon the filament spacer and its >attaching means. As a further alternative-to forming the grid by use of an anode-simulating element, as de underlying mica ring I|5. As in the procedure scribed in connection with Fig. 2, the same func I |3_, being supported through the iilamentbyi the described in connection with Fig. 2,'a location- _ determining agency |40 having a particular di mensional relationship to the anode which is to be used in the tube is forced down against the grid |35 to produce a predetermined deformation of it. After this operation is performed, the cath ode parts ||0 and ||| are locked in the position which they then occupy by means of a jig having an outer component |42 and an inner, relatively mov (Il tionmay be accomplished by appropriate manip ulation of the cathode parts as indicated in Fig. 6. (In this figure, parts corresponding to elements previously described bear similar reference nu merals differentiated by priming.) In the in tended location of the anode there is provided a location determining agency |00 which diiiers from lthe anode in by an amount corresponding to the desired spacing between the anode and able component |43, these being adapted to be ‘ secured in ñXed relation by a set screw or other means, not shown. With the jig in locked rela tion, the cathode structure (after adjustment) is removed from the tube assembly and its parits welded together in the manner previously de scribed. Thereafter, upon removal of the spacer'upon the cathode sleeve 29'. This drives the ac 20 cap |38 and restoration of the cathode structure toits original position in the tube assembly, the tive part of the cathode structure in an upward desired fixed spacing between the cathode »fila direction, carrying with it a spacer 69’ which acts ment and the grid |35 will have Vbeen attained. against the lower surface of the grid to deform The desired spacing between the anode and the it. Upward pressure is applied to the jig 10’ and downward pressure to the part |00, as indicated by 25 grid is, of course, produced by substituting for grid, the intended length of the anode being indicated by the dotted line I0|. The grid 51’ is pressed upwardly against the lower extremity of the element |00 by pressure suitably applied to the lower extremity of a plunger 1|' which acts the arrows A and B respectively, so that all the elements of the tube structure are placed under compression. A completed discharge device the location-determining element |40 an anode whose length differs from that of the element by the desired amount. Certain aspects of the invention are Valso ap formed in accordance with the procedure illus trated in Fig. 6 is shown in Fig. '1, the lower part 30 plicable in connection with the fabrication of two Y element 'discharge tubes. This is illustrated in of the tube being broken away to conserve space. The invention may also be applied in connec Figs. 11 and 12 which show respectively a oom pleted diode of a type described in my Vcopending tion with the fabrication of a tube in which the application S. N. 436,633, and an intermediate cathode takes the form of a directly heated fila ment rather than an indirectly heated construc 35 step in the manufacture of such a diode. The tube referred to includes an apertured cir tion as in Fig. 1. This possibility is illustrated for cular part |48 having an indirectly heated cath example, in Figs. 8, 9 and 10, the last two ñgures ode extending through its central opening. As showing the structuralv details of a completed in the construction of Fig. 1, the cathode com cathode structure of the type in question. As appears most clearly in Fig. 10` the cathode 40 prises an active disk |40 to which is secured a de pending sleeve |50 and a cylinder of metal foil includes a supporting part IIII which is in tele I5|, the cylinder being telescoped over and weld scoping relation with a metallic sleeve I I | form ed to a correspondingly shaped suporting part ing the lower component of the active part of |52. A iilamentary heater |53 is provided within the »cathode structure. The emissive portion of the cathode is in the form of a V-shaped ñlament 45 the interior of the cathode, being supplied With heating current by means of lead-in terminals ||3 (Fig. 9) which extends across the upper face |55. Additional lead-in conductors |56 are pro of the cathode structure. The ñlaments which vided for the purpose of supporting the cathode make up the sides of the V rest at their extremities structure and supplying it with unidirectional po upon the upper surface of a mica washer ||5 which is held in place by the fact that the edge 50 tential.` Close capacitive coupling between the cathode Vstructure and the part |50 is provided' of the part ||| is crimped over to provide a re taining means as indicated at IIS. (The upper edge of the part ||| -is cut away at appropriate regions to avoid interference with the filament by means of a flat metallic member |55 which is connected to the cathode and which is insulat ingly spaced from the part |50 by means of a@V | I3.) ` The apex of the filament V is engaged by a 55 mica spacer |60. spring arm I |8, whereas the extremities of the V are attached appropriately formed terminals ||9 and |20. These terminals are »clamped between the mica washer | I5 and a second similarly shaped mica washer |22 positioned below it, the in wardly extending parts of the terminals being shown in Fig. 10. Current is supplied to the fila ment by wires |24 which connect with lead-in conductors |25 shown only in part. The sup The lower opening of the circular member |48` is closed .by means of a generally cup-shaped part I5! which is reverse'ly bent to provide a circum ferentially extending‘trough portion |52.V This latter portionA is adapted to receive the extreme edge Vof the member |40 and when filled with solder as indicated at |03 provides a vacuum-tight seal -for the tube enclosure. The lead-in wires |55 and |56 are‘sealed through the part |6I by porting structure for the cathode is quite similar 65 means'of a plurality of glass-to-metal'seals shown at |64. ' " to that described in connection with Fig. l and ` The> lower edgeof the cup-shaped part IBI is includes a circular flange |30 which bears against provided with bent-in tabsV |06 which serve to an insulating washer I3 I , the washer in turn being engageand'retain a socket adapter |61 consti pressed against the lower vsurface of a metallic envelope part |32. The upper end of the cathode, 70 tuted of a suitable insulating material, such as a synthetic resin. The adapter is provided with aspecifically the filament ||3, is, in the completed form of the tube, desired to be spaced a particular distance from the grid |35 (Fig. 8). In order to produce the desired grid-to-cathode spacing, a’spacer capl |38 is placed over the upper end of 75 centering lug |61" and supports a number of hol low contact prongs |58 towhich the Vextremities'l of the conductors |55 and |56 are attached. The anode of the device' comprises- ‘a disk |60 2,411,184 10 which is- supported in fixed spaced relation with respect tothe active surface of the cathode by ' 4; Afmethod of fabricating an electric discharge device having a first electrode structure and a sec ond electrodestructure which includes an active part and a supporting part; which method com being sealed to the end of a glass cylinder |10. In the fabrication of the tube the anode |69 and the base part |48 are first sealed to the re prises installing said ñrst electrode structure in spective extremities of the glass cylinder |'|0. its desired location in the device, placing said sec Thereafter these elements and the loosely assem ond‘structure in approximately its desired loca bled cathode parts are positioned in a line-up jig tion in the device and with its parts in loose having a fixed part |80 and two concentric mov ` assembly, moving said parts relative to one an able parts |8| and |82. (See Fig. 12.) At this 10 other into precisely their desired relationship stage, the insulating disk |00 is omitted for a with respect to said first structure, and thereafter reason which will shortly appear. By pushing joining said parts in fixedassembly to assure the the jig parts IBI and |02 concurrently in the up subsequent preservation of the said relationship. Ward direction, the ñange of the cathode part 5,. The method of fabricating a discharge device |52 is caused to seat ñatly against the under sur having a first electrode structure of deformable face of the part |48 `and the cathode cap |49 is character and a second electrode structure which pressed against the anode |69. includes the assembly of an active part and a sup A Thereafter, the cathode assembly is “frozen” (by Vlocking the jig parts `|8| and |82 together) and withdrawn from the >tube so that the cath ode parts may be welded in ñxed relationship Finally, the cathode is mounted on the base |"6| and reinserted in the tubein the arrangement porting part; which method comprises installing said first structure in approximately its desired 20 location in the device, installing said second structure in approximately the desired relation ship with the ñrst structure and with its parts in loose assembly, deforming the said first struc shown in Fig. 11, the insulating washer |60 be ture to bring it more precisely into the desired 1o ing now included. By comparing Figs. 11 and 25 cation, modifying the assembly of said second 12 it will be seen that the resultant spacing of the cathode with respect to the anode |69 cor responds precisely to the thickness of the Washer, structure to bring its active part more precisely into the desired relationship with the iirst struc ture, _and thereafter fixing the assembly of the which may be made asgreat as is desired for second structure to preserve the said desired re the particular application at hand. lationship. In cases where the cathodestructure and the base part |50 of Fig. 11 are desired to be at the sameÍ potential, a metal Washer may be used as a spacer in place of the insulating disk |60. As a still further variant, in a case where the anode is of the type employed in the construction of Fig. l, the desired anode-cathode spacing` may be obtained by inserting a washer of proper thickness under the anode terminal cap after the anode and cathode have been brought into abut ting relation and the cathode parts joined in ac cordance with a procedure such as that just de scribed. . While the invention has been described by spec ifying various procedural steps as being taken in a particular order, it will be understood that a considerable variation in the order of procedure is possible, and I aim in the appended claims to . 6. The method of fabricating a discharge de vice having a generally planar grid constituted ofV deformable material and a cathode which in-V cludes a supporting part and an electrically active part; which method comprises installing said grid in approximatelyl its desired location in the de vice, placing said cathode in approximately its de sired relationship with respect to the grid and with its said parts in loose assembly, deforming the said grid to cause its active portion to occupy a plane more nearly at‘the desired location, mod ifyingthe cathode assembly by relative motion of its parts to cause the said active part to assume a desired spacing with respectto the said active . grid portion, and thereafter ñxing the assembly of said parts to assure the preservation of the cover all such equivalent variations as come with said spacing. '7. A method of fabricating a discharge device having an envelope, an anode, agrid of deform in the true spirit and scope of the foregoing dis able material and a cathode which includes active closure. and supporting parts capable of being assembled in engaging relation; which method comprises in stalling said grid in said envelope, positioning said active cathode part in substantially its proper a VWhat I claim as new and desire to secure by Letters Patent of the United States is: 1. A process of fabricating a discharge device having an electrode of deformable construction, , which process comprises installing the electrode approximately in its desired location in the de vice and thereafter deforming the electrode in situ to bring its active part more precisely into the desired location. 6 2. A process of fabricating a discharge device having a grid constituted of deformable mate rial, which process comprises installing the grid relation to said grid, `arranging said supporting part of the cathode in its intended location with respect to said envelope and in loosely engaging relation with said active part, deforming said grid to bring it more precisely into its desired location, bringing the active part of said cathode struc ture more precisely into its proper relation to said grid by adjustment of such part with reference to the said supporting part, securing said cathode approximately in its desired location in the de parts to one another in the relation which they vice, and thereafter deforming the grid in situ to 65 then occupy, and finally completing the assembly of said device. bring its active part more precisely into the de sired location. 8. A method of fabricating a discharge device 3. A methodl of fabricating a discharge device having an envelope, an anode, a grid »of deform having an electrode of deformable construction, able material and a cathode which includes sepa which method comprises installing said electrode 70 rate active and supporting parts capable of being in approximately its desired location in the de mutually joined; which method comprises the vice, positioning location-determining agencies on following steps, installing the grid in said enve- » opposite sides, of said electrode, and deformingA the electrode by said agencies, thereby to effect lcpe in substantially its intended location, posi tioning the active cathode part in proximity to a more precise location of a part of said electrode. 75 said grid with a spacer of predetermined thick 2,41 1,184 ll ness between them, arranging said supporting part in its intended location with respect to said envelope and in proximityvto said active part, de forming a portion of said grid to bring it more preciselyinto its desired location, moving said active cathode part with reference to said sup porting part to establish between said active cath ode part and the deformed portion of said grid‘a spacing determined by the thickness of sald 12 f thickness between them, adding to said >assem-bly on the anode side of said grid an agency having a surface which vcan be located with cer tainty'in a plane which is a iixed distance from the desired location of the active part of‘said anode, moving said surface against» the grid to bring the active part of the grid into the said plane while concurrently deforming said cath-y ode by the action of- said spacer to preserve-a: spacer, joining saidv cathode parts in the relation 10 fixed spacing between the grid and cathode and thereafter withdrawing said spacer andV said> which they then occupy, removing said spacer, agency and completing the permanent-assembly and completing the assembly of said device. 9. A method of fabricating a discharge device of said electrodes. . Y 13. A method of fabricating a discharge d_e-- Y having three electrodes, the intermediate elec trode being a grid of deformable material, which 15 vice having a first electrode and a second electrode which includes as separable componentsy method comprises temporarily assembling said an active part and asupporting part; said meth grid and a selected one of said remaining elec od comprising the steps of disposing said-.iirst trodes in approximately their desired relation electrode in its desired location in said device,y ship in the said device, interposing between said Y electrodes a vspacer having a thickness equal to 20 disposing the supporting `part of said second.V electrode at a fixed distance from the first elec the desired spacing of the electrodes, adding t0 the assembly an agency having a surface which trode and in approximately its desired relation can be located with certainty in a plane which is a fixed distance from the desired location of the the active part of said second» electrode in abut ship> with respect -to such electrode, arranging third electrode, moving said surface against the 25 ment with said first electrode and in its desiredl relationshiprwith respect to said supporting part, grid to bring the active part of the grid into the fixing said active and supporting parts in the said plane while said spacer maintains the grid relationship which they then occupy, displacing in fixed relationship with respect to said one elec the whole structure of one of saidrelectrodes from trode, and thereafter withdrawing said spacer and said agency and completing the permanent 30 its originally assigned location byv an> amount corresponding to the spacing desired to exist be assembly of the electrodes.V tween the said active part yand the> first elec 10. A method of fabricating a discharge de trode, Vand without subsequnt displacement of vice having a first electrode which is of deform the parts completing theiixed assembly of the able character and. a second electrode, which method comprises installing said electrodes 1n 35 14. A method of fabricating a discharge de _ approximately the desired location in the device, vice having a cathode which includes. an active interposing a spacer of predetermind dimen part and a supporting partadapted to be assem sions between the electrodes, and moving said bled in telescoping relation,Y a second electrode second electrode to force said spacer against the first electrode with resultant deformation of it, 40 adapted to cooperate with said cathode, and anl device. thereby to bring the active parts of both said electrodes more precisely into the desired loca tion in said device while concurrently establish ing a desired spatial relationship between them. 11. The method of -fabricating a discharge v . v envelope >for enclosing said cathode and saidV second-electrode; said method comprising dis posing said second electrode in its desired loca tion in said envelope, disposing said cathode in the envelope with its parts in loosely engaging relation and with its supporting'part at a‘iixed distance from said second electrode, moving the active part of the cathode with reference to the terial, which method comprises temporarily as supporting part to bring it into abutment with sembling said intermediate electrode and a'se lected one of the remaining electrodes in ap 50 the second electrode, fixing said cathode parts in the relationship which they then occupy, dis proximately their desired relationship in thîe placing said supporting part from its originally said device, interposing between said electrodes assigned location in the envelope by an amount a Spacer having a thickness corresponding to corresponding to the spacing desired to exist the desired spacing of the electrodes, adding to said assembly anagency having a surface which 55 between the anode and cathode, and without subsequent change in ~the relationship 0i" the can be located with certainty a` fixed distance parts completing the permanent assembly of the from the desired location of the active surface of device. said third electrode, »moving said selected elec l5. A method of fabricating an electric dis trode toward said intermediate electrode with out withdrawing said spacer, thereby by de 60 charge device having a first electrode structure and also having a second electrode structure formation of material to force the active por which includes a cylindrical supporting part and tion of said intermediate electrode against the a conformingly cylindrical active part; which said surface of said agency while maintaining method comprises installing said iirst electrode the desired spacing of said selected and inter mediate electrodes, and thereafter withdrawing 65 structure in its desired location in the device, said spacer and said agency completing the placing said second structure in approximately its permanent assembly of the electrodes. desired location in the device with its said cylin 12. A method of fabricating a discharge de drical parts in slidably interiitting relation, rela vice having three electrodes including a grid and tively sliding said parts to cause the said active cathode of deformable character and an anode 70 part to assume precisely a desiredY spacing with of non-deformable l character, which method respect to said first electrode structure, and device having three electrodes, the intermediate electrode being constituted of deformable ma comprises temporarily assembling said grid and cathode in approximately their desired location in said device with a spacer of predetermined thereafter fixing the assembly of said parts to assure the preservation of the said spacing. JAMES E. BEGGS.