US2398608A - Electron discharge device - Google Patents

Description

April 16, 1946. L. c. WERNER ET AL 2,398,608-

ELECTRON DISCHARGE DEVICE Fiied Oct. 1, 1941 I 2. Sheets-Sheet 1 INVENTORS, Z C. WEE/V67? J" 49/4 E) I mm ATTORNEY April L6,, 1946. c. WERNER ET AL ELECTRON DISCHARGE DEVICE Filed Q91. 1, 1941 2 Sheets-Sheet 2 IN'VENTORS 4 c. WEE/ME)? ADAM ATTORNEY Patented Apr. 16, 1946 ELECTRON DISCHARGE DEvIoE Leo Carl Werner and Hampton Jennings Dailey, Bloomfield, N. J., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a

corporation of Pennsylvania Application October 1, 1941, Serial No. 413,168

p 8 Claims. 01. 250-275) a filament and in the assembly and retention of those strands in the electrode structure. Precision of bending of filament wires has necessitated more or less elaborate dies and mandrels as well as methods to be employed which have'been time-consuming and otherwise unsatisfactory in use. The distortionof the wire used has left stresses therein, not immediately apparent always, but which develop a warping of the filament in service, and such as to affect the tube characteristics. pears to result in many instances from the fact that the part of the filament wire which is bent during fabrication becomes in use part of the length of filament between supports. In consequence of that fact, even very slight stresses in V the curved portion of the filament produce considerable deflections in the otherwise straight part of the filament. Furthermore, a die. or mandrel-formed filament, in view of the resiliency of the wire when bent, has to be baked while I through. Consequently, a baked filament very frequently warps after installation and when then; rendered incandescent in use, often results in the rejection of the whole device, thus representing a substantial financial loss. An object of the present invention is accordingly to provide a construction of a bent filament wherein the set may be performed after installation on its support and before completion of the electron discharge device.

confine the bend to a partof the filament where anystresses developed will have minimum defleeting or deforming effect upon the general lengthof the filament. I

The difficulty mentioned ap ment to incandesencewith current passing there- Another object of the present invention is to A further object'of theinvention is to provide a filament in which the set may be accomplished by heating in hydrogen while the filament is rendered incandescent from passage of an electric current therethrough.

Again, an object of the invention is toprovide a simple, light and effective spacer element which will position and hold thefilament. i

A still further object of the inventionresides in the method of manufacture of an electron discharge device, particularly as to application and retention of a filament therein.

' Other and further objects of the invention will appear to those skilled in the art as the description progresses,- both by direct statement thereof and by implication from the context.

In the accompanying drawings, wherein like numerals of reference indicate similar parts throughout the several views, and wherein a preferred physical embodiment of the invention is disclosed by way of example:

Figure '1'is a central vertical section of an electron discharge device'embodying the present invention;' i V i "Figure 2 is a plan of-the filament assembly as viewed on line II--II of Fig. l, but with increased scale 'thereover; i Figure 3 is a cross-sectional view on line III- ,III of Fig. l, and on a scale corresponding to that of Fig. 2; i r

Figure 4 is an elevation of one group of filament strands forming a complete series circuit with the source of current supply;

Figure 5 is a plan of a portion of one of the upperspacer elements with the bight of the filament section therein and showing the parts before the clinching tab is bent to holding position; i I Figure 6 is a sectional view on line VI-VI of Fi and V Figure 7 is a similar sectional view showingthe tab bent to its holding position.

In the specific embodiment of the invention illustrated in said drawings, a part of an electronic discharge device, generally identified as a transmitting tube, is depicted exemplifying the invention as part thereof. It should be understood, however, at the outset, that the invention is applicablerto other electronic devices than the particular transmitting tube'here selected for illustrative purposes. r r 1 The specific tube shown comprises a glass or otherceramic bowl -or casing portion [0, here represented as part, of an evacuated envelope, and as also constitutingthe base portion for the device, for which purpose it is equipped with appropriate prongs I! protrudin from the bottom thereof. These prongs are each preferably unified with appropriate posts, such as l2, l3, l4 and i5 shown in Fig. 3, extending upwardly within the interior of said bowl or base portion it). At the upper rim of the bowl portion I0, there is sealed into the glass or other ceramic a feather edge of a connecting ring-like portion I6 to a metal upper portion which in part also constitutes the anode IT. A part of the anode proper is shown re-entrant with respect to the connecting rim or ring portion l5, thereby p oviding an annular upwardly opening exterior groove I'I' serviceable in connection with cooling the anode in use.

Within the anode l1, spaced in parallelism to the same, is a bird-cage dome-like grid. l8 providing a plurality of similar strands l 9 in generally vertical planes, evenly distributed circumferentially and providing lowerportions which are parallel to each other and upper portions which curve upwardly inward to a common vortex to obtain the dome-like contour of grid. Said grid is also shown as having a helically wound Wire 28, each point of crossing of which with the strands I9 is spot welded or otherwise secured, to constitute the strands and helically wound wire a unitary grid structure. The lower ends of the several strands l9 arev secured to a horizontally 30 disposed plate 2!, as by screw and nut means 22 shown. Said plate is provided with a central opening 23 therein for passage of other terminal connections and posts therethrough, and is also provided with a peripheral rim or skirt at its edge for obtaining desired rigidity. A plurality of posts, of which post I5 is representative, support strands 24"of the group are in electrical series to the source of current supply. Other like groups 7 nate sections thereof are duplicates. Two adjaare in parallel to each other although the strands of each group are in electrical series within the group. A maximum electron emitting surface area for copious flow of electrons is thus provided with minimum current consumption.

In the fabrication of the filament assembly 24, a plurality of generally parallel spacer members are provided, namely, three next the bottoms of the strands and two next'the top. Of the bottom three spacer members, the lowermost one is designated by numeral 25 and is situated horizontally or transverse to the filament strands. Physically and electrically spaced a short distance above this lower spacer member 25, and parallel thereto, is a second or intermediate spacer member 26. These two spacer members are connected to opposite poles of the source of filament current supply, as indicated in Fig. 4. Next above the intermediate spacer member 26 is a third or neutral spacer member 2'! likewise parallel to and electrically distinct from the other said spacer members. All of these spacer members are preferably of plate formation, the lowermost one, 25, having a central aperture 25' permitting free passage therethrough without contact, of post 13 the upper end of which is electrically and 60 ate spacer member.

physically secured to the next or intermediate plate-like spacer member 26. This post I3 represents one lead-in means for the supply current to the filament. The lower spacer member 25 is supported by welding, brazing or otherwise sebracket secured upon the tops of posts [2 and I4 and forming therewith electrical circuit from the filament to the other pole of the source of current supply. Bolts or other holding means 30 extend through the three spacer members described with suitable insulation from at least two thereof, thereby obtaining rigidity with electrical separation.

At the top of the filament assembly are provided two spacer members forming an important 0 part of the present invention. Each of said spacer-members for the top part of the filament is of a generally flat, ring-like or endless configuration. Said members are also physically and electrically spaced from each other and arranged to providean upper spacer member 3| and a subtended parallel spacer member 32, both also being parallel to the spacer members at the bottom part of the filament.

It isnow appropriate to point out that each group of strands constituting an electrical series, is made up of two lengths of wire each bent in the form of a hair-pin and referred to here as a filament section. Two such sections are shown as comprising each group of series-connected u strands. The bent portion, referred to as the bight of the filament section, is engaged in one of the upper spacer members, whereas the bight of the other hair-pin formation is engaged in the other spacer element. As the potential at the bight of all filamentsections engaged in one spacer member is the same, said spacer members are conveniently made of metal, but may be of non-conductive material if found more expedient. A desirable characteristic is that they shall be of minimum mass or light in weight as they are entirely supported by the filament strands, and should develop minimum momentum under con ditions of jarring the electron discharge device.

In the general assembly of the filament, altercent sections comprising a single group in effect constitute an M-shape with one top bight a little lower than the other due to the spacing of the two upper spacer members one below the other.

The end legs of the M-shape have their lower ends correspondingly one lower than the other since one such outside leg is connected to the lower or first spacer member and the other outside leg is connected to the next above or intermedi- The two middle legs of th'e M-shape are both physically and electrically connected to the third or neutral spacer member and are accordingly shorter than either of the end legs. All three of these lower spacer members are electrically conductive and are provided with projecting and staggered ears 33, 34 and 35 at the peripheries thereof, so that strands to the lower spacer member ears 33 may pass between the ears 34 and 35 of the other two members, strands to the intermediate member may be secured to the projecting ears 34 thereof and passbetween the ears 35 of the upper one of said members, whereas the strands to the upper one of the members may be secured to the ears 35 thereof and'thus locate all of the strands in a single circle with lower spacer members.

section with the bight of the section overlying the portion of the ear intervening between said holes. A tab 38 is formed integral with and at the inside edge of the ear, said tab being bent upwardly outward to clinch over the top of the bight after the filament section is slid home through said holes. If desired, the tab and/or filament bight may be spot welded or otherwise rendered that much more secure to the spacer member.

It now follows from the foregoing description, that assembly is effected by inserting the legs of appropriate hair-pin filament sections, while the metal is still in pliable form, through the .prepared holes in the spacer member ear, duplicating the procedure for all ears of both spacer members. Since substantially all of the bend effected in the metal forming the bight is situated in the ear above the holes, the walls around the holes will resist any effort made by the resiliency of the wire or by internal stresses, from deflecting the strands out of parallel relation. Clinching of the tabs may now be effected, either before or after which the lower ends of the strands are welded or otherwise secured to their respective The filament assembly is then introduced in hydrogen and rendered incandescent while therein by passage of an appropriate electric current through the filament, and the filament assembly thereafter inserted in place with other parts forming and completing the electron discharge device. Heat treatment by current causing incandescence obtains a permanent set in the filament metal, and accomplishment of this set prior to incorporating the filament in the electron discharge device enables said filament to be inspected while still a separate entity. However, mounting in place may take precedence to setting the metal if preferred, in which event the device may be evacuated through tubulation 39, hydrogen introduced therethrough, the filament ignited, the tube again evacuated and completed in usual manner.

We claim:

1. A spacer member for filaments and the like, comprising an endless narrow ribbon-like member having pairs of holes at intervals for reception of strands of filament wire bent in the area spanning the holes of a pair of holes.

2. A spacermember for filaments and the like, comprising an endlessnarrow ribbon-like member having pairs of holes at intervals for reception of strands of filament wire bent in the area spanning the holes of a pair of holes, and means for retaining said filament wire in place in said holes. I

3. A spacer member for filaments and the like, comprising an endless narrow ribbon-like member having pairs of holes at intervals for reception of strands of filament wire bent in the area spanning the holes of a pair of holes, and means bendable over the bight of said filament wire for holding the said filament wire in place.

4. A spacer member for filament wires and the like wherein said wire is bent intermediate its length to provide parallel strand portions and a bight portion, and wherein said spacer member provides holes for passage of said parallel strand portions therethrough, the combination of a tab integral with said member and bendable over said bight portion of the filament wire for retaining the bight portion next the member at the area intervening between the holes. 5. A spacer comprising an endless ribbon member having portions protruding and other portions receding, said protruding portions constituting ears, each said ear having a pair of holes and all of said holes equi-distant from a common center, filament strands in each said hole, and means supporting said member from said strands.

6. A filament structure comprising a pair of spaced and parallel endless ribbon members each having peripherally projecting ears with the ears of one member staggered with respect to the ears of the other member, each said ear having a pair of holes, filament strands depending from each said hole, the strands from the upper of the said members passing out of contact from the other member, and means at the lower end of said strands for completing the electric circuit with respect thereto.

7. A filament structure in accordance with claim 6, wherein means is provided at the upper parts of the filament strands securing the same to their respective said members.

8. A filament structure in accordance with claim 6 wherein means is provided integral with said members and in intimate contact with said filament strands for supporting the said members from the respective said strands in the holes thereof.

LEO CARL WERNER. HAMPTON JENNINGS DAILEY.

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