US2348216A - Electron discharge device mount spacer - Google Patents

Description

May 9, 1 944. D. F. HOLSHOUSER ELECTRON DISCHARGE DEVICE MOUNT SPACER Filed Feb. 9, 1943 a v m TO N NHWR f m N T I A Patented May 9, 1944 ELECTRON DISCHARGE DEVICE MOUNT SPACER Don F. Holshouser, East range, N. J assignor to Radio Corporation of America, a corporation of Delaware Application February 9', 1943, Serial No. 475,239

6 Claims.

My invention relates to electron discharge devices and particularly to methods and means for supporting electrode structure within an enclosing envelope and to electrical contact means for such devices.

In many electron discharge devices it is necessary to-mechanically support a relatively long electrode structure against transverse movement when subjected to shock or gravitational forces and it has been customary to provide springfingers or metal strips aflixed at oneend of the electrode structure to be supported and bearin against the envelope wall at the opposite end or ends thereoL...Such strips are. resiliently deformed by stresses comprising both tension and compression in the strips, and such. strips. being subjectedto the various baking and heating steps duringtube fimanuiacture suffer a loss in their resiliency. whereupon their efficiency is impaired. Consequently, a great number of such strips such as eight to twelve separate strips may be required in .an individual tube for adequate support. The .inefiiciencyof such strips is particularlyobjecti'onable in discharge devices of the cathode ray type having a relatively massive electrongun and deflection plate structure supported withinthe neck section of the tube from the sealed or stem end.

It is an object of my invention to provide resilient support members or spacers for supporting electrode structures in electron discharge devices -.which. will not become defective during manufacture oruse of the devices. It is another object t'o prdvide a resilient electrical contact through which electrical connection may be made to electrode structure within a discharge, tube. It is a. further object to provide improved electrode'mount supporting means which are easy to j assemble, rugged in construction, inexpensive to manufacture and which at the same time provide adequate support for relatively massive electrode structures. In accordance with my invention I provide one or more resilient spring members each aflixed to a transverse support on the electrode mount assembly, preferably surrounding the transverse support and affixed thereto at a plurality of points, the resilient member or members. being continuous around the support and having no free ends so that upon insertion of the mount assembly within a glass envelope or other container the resilient member or members are stressed in compression throughout the.

the resilient member or members may serve as electrical conductors to electrically connect electrodes within the envelope such as a conductive wall coating to one of the mount electrodes. These and other objects, features and advantages of my invention will become apparent when viewed with respect to the following description and the accompanying drawing wherein:

Figure 1 is a longitudinal view of a discharge device of the cathode ray type incorporating my inventioniand Figure 2 is a perspective view of the electrode mount structure shown in Figure 1. a a

While I will describe my invention with particular reference to its application in cathode ray tubes, it will be appreciated that it is nevertheless equally applicable to other electron discharge devices where it is desirable or necessary to, support the electrode structure from'the' bulb side walls. Referring to Figure 1, I have shown a cathode ray tube comprising an envelope, generally designated I, having a neck section 2, a stem, not shown, closing one end of the neck section and supporting the electrode mount structure -3, the opposite end of the tube being provided with a screen or target 4 with a conductive wall coating 5 intermediate the stem and target." The mount structure 3 comprises conventional electron gun electrodes which it is dei sired to support within the neck section 2, the

structure comprising more particularly a conventional centrally apertured grid 6 enclosing the usual cathode and heater (not shown), a cylindrical anode 1 and a plurality of apertured anode discs 8, 9, I0 and H. The anode 'l is supported from the stem such as by a plurality of ceramic rods I2 and the discs 8-l| are in turn supported from the anode 1 by additional ceramic rods l3 which may likewis be used to position and support conventional electrostatic deflection plate pairs 4l5. In accordance with the usual construction of such tubes, the anode discs -8l I may be maintained at increasing positive potentials by connecting lead wires extending through the stem of the tube from the base member IE, it being customary to apply the highest potential to the anode disc nearest th target 4 such as the. disc .H and also to the conductive coating 5.

In accordance with my invention I provide a transverse member supported by the mount structure 3 such as'the anode discs III or and aifix thereto a resilient mount support spacer ll as best shown in Figure 2. I preferto utilize two such mount support members l1- although one or more may be sufiicient depending upon the degree of support required for any particular appli cation. The mount support spacer or spacers in accordance with my invention are continuous bands of resilient material such as thin metal stripping affixed to the transverse mount support at a plurality of points such at the points I8. I prefer to form the spacer or spacers I! in the shape'of a three-lobed heart cam contacting and affixed to the anode disc or discs at three equally spaced points about the anode periphery so that the lobes of the mountspacer extend be-- to a circle concentric with the longitudinal axis neck diameter of 1.86 inches and tolerances of $0.120 inch utilizing spacers having a total length surrounding the transverse members of 5.75 inches allowing an overlap at the ends of 0.020 inch. The unstressed spacer has a maximum radial dimension of 1.01 inches between the axis of the mount structure and each eventual point of contact with the bulb wall prior to assembly, this dimension being reduced to the radius of the bulb neck section following assembly. It will be noted from the drawing that Iiutilize the spacer I! as an electrical contacting yond the periphery ofthe anode and lie tangent 1 planar so that no longitudinal stress, is applied c to the mount assembly. The mount spacer material may be of metal such as a nickel-chromium alloy usually referred to as ,Nichromeor Inconel or other resilient material capable of re-. taining its resiliency upon heating to the temperatures usually reached during tube manufacture such as attained at bake-out temperatures of 300 to 500 C. Although I have shown the transverse support members and II as being of circular shape, this is not at all necessary, the shapebeing determined merely by the otherrequirements of electrode structure. The only requirement is a plurality of preferably equally spaced points to which the spacer is affixed such as by welding, these points being at equal radial distances from. the longitudinal axis of the electrode structure. j 7 1 The spacer material'maybe of Nichrome strip having a thickness of from .O02-.010" and a width of A; to A". This thickness and width is sufficient for proper rigidity of a mount structure such as'contained in the commercial cathode ray tube type RCA 5CP1 when utilizing two such spacers'as shown in the drawing. When utilizing two such spacers of equivalent dimensions in a uniform diameter envelope portion it is desirable to displace the pointsof contact which one spacer makes with the envelope with respect'to the corresponding points of the other spacer so that these points are unaligned in an axial direction. When utilizing two three-lobed spacers the points of' contact on the envelope wall are displaced one from the other by degrees around the inner periphery of the envelope. I

I choose the length of the material comprising the spacers I1 less than the inner circumference of. the envelope wall'at the eventual points of contact such that'following shaping in the desired. 'form and attachment to -the transverse members at the'plurality of points, 18 the mount assembly may be forced into the neck 2 of the envelope 1 before the stem. is sealed to' the lower end of the neck section; Upon assembly in the envelope the lobes of the spacers are forced inwardly" toward the mount axis stressing each portion of the spacer between the points of support on the transverse member. wholly in compression, Such a mode of support is far more rigid for a given thickness and width of spacer material than for a spacer which has means between the anode disc II and the conductive wall coating 5, the three points of support combined with the fact that the spacer is wholly in compression providing excellent electrical contact to the coating 5 so that it may be operated at the same potential as the anode disc I]. To prevent abrasion of the coating 5, the spacer may have a slight rounded rib or embossed portion l9 to provide smooth engagement between the coating 5 and the spacer'a's' the mount is slipp'edintothe neck portion 2.-

While I have described only one specifice'mbodiment of my invention and have described its use with particular reference to a cathode'ray tube, it will be appreciated that other modifications may be made and various uses contemplated without departing from the scope of myinvention as set forth in the appendedclaims.

Iclaim: 1. An electron discharge device comprising an envelope having a tubular portion, an electrode structure within said tubular portion, a transverse member on said structure and a resilient envelope spacercompletely surrounding said transverse member having points of. contact with said envelope and afflxed to said transverse member at points intermediatesaid' points of contact. r

2. An electron discharge device'comprising an envelope having atubular portion, an electrode mount structure within said tubular portion, a transverse member supported by said mount structure and a continuous spacer, completely surrounding said member affixed thereto at a plurality of spaced points and restrainedby said envelope at a plurality of points eachintermediate two of said spaced points. j

3. An electron discharge device comprisinggan envelope having a tubular portion, an electrode assembly within said tubular portion, atransverse member supported by said electrode assembly and a metal strip completely surroundin said transverse member and extending .to and abutting said tubular portion at a plurality of spacedpoints about its periphery, the said strip being affixed to said transverse member at a similar plurality of points each of which intermediate two points of abutment against said tubular portion. 7.

4. An electron discharge device comprising an envelope having .a tubular section of predetermined internal diameter, an electrode mount structure within said section, a transversemembersupported'by said mount structure and a continuous band of metal. having a length less than the inner circumference of said tubular section affixed to said transverse member at-a plurality of points about its periphery, portions of said band of metal extending to and engaging said tubular portion at a plurality of points intermediate said affixed points.

5; An electron discharge device comprising an envelope having. a predetermined internal diameter, an electrode mount structure within said envelope, a transverse member of smaller diameter than said envelope supported by said electrode structure, a single strip of metal completely surrounding said transverse member and attached thereto at three equally spaced points about the periphery thereof, said strip contacting the inner wall of said envelope and portions of said strip lying between each of said points of support on said transverse member being arcuate-shaped between each of said points of support and the point of contact between said strip and said envelope.

6. An electron discharge device comprising an envelope having a tubular portion, a mount structure within said envelope, a pair of axially spaced transverse members supported by said mount structure, a single strip of metal completely surrounding each of said transverse members attached at a plurality of points thereto and contacting said envelope at other points intermediate said points of attachment, the points of contact with said envelope of one of said metal strips being unaligned in an axial direction with the corresponding points of contact of the other of said metal strips.

DON F. HO'LS-HOUSER.

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