US2454834A - Manufacture of base assemblies for electric discharge tubes - Google Patents

Description

. S. J. MANUFACTURE OF BASE ASSEMBLIES FOR NOV. POWERS ELECTRIC DISCHARGE TUBES Filed Jan. 12, 1944 Patented Nov. 30, 1948 g MANUFACTURE OF BASE ASSEMBLIES FOR ELECTRIC DISCHARGE TUBES Stephen John Powers, London, England, assignor,

. a by mesne assignments, to International Standard Electric Corporation, New York, N. Y., a

, 1i corporation of Delaware Application'JanuarylfZ, 1944, Serial No. 517,945 In-Great Britain April 21, 1943 Claims. (01. 49-78)v v 1 2 The present invention concerns improved meth sembly with the conductor wires sealed to the ods of sealing the electrode leads through the disc; and

envelope of an electric vacuum or gas-filled tube of any type. i

It is applicable to any device or tube such as a cathode ray tube, for example, or a thermionic valve having electrodes mounted inside an envelope, which envelope may be exhausted or filled with gas at any pressure. It has previously been common practice in such tubes to seal the leads for the electrodes through a stem or press of glass, or ceramic material, or the like,.or through a substantially flat base, the stem or base being then sealed to the envelope.

' It is proposed to use a flat disc or base of glass provided with a central exhaust tube and formed with U-shaped radial slots around the periphery. The electrode conductors comprise short wires or rods each carrying a small glass bead. The'wires are placed with the beads in the slots, and the base is inserted into the neck of the envelope of the device, and the wires are sealed into the base and the base to the envelope in one operation.

One of the advantages of the arrangement is that it enables the electrode conductors to. be spread apart as widely as possible, so that they may lie in a circle not much smaller than the cross-section of the neck of the tube. The present invention employs another method of sealing the leads through a disc of similar type which does not involve sealing the disc to the envelope of the tube in the same operation. The advantage of having the conductors spread out by the maximum amount is retained.

The invention accordingly consists in the method of making a base assembly for an electric vacuum or gas filled tube which comprises locating conductor wires in peripheral slots of a disc of fusible material, softening the disc by heat, squeezing it between a pair of dies, and rolling a tool around the edge of the disc in sucha mannor as to close the slots on the wires so that they are hermetically sealed through the disc.

The invention will be described with reference to the accompanying drawings in which:

Figure 1 is a top view of a glass disc or base for a vacuum tube;

Figure 2 is a section taken on line 2-2 of Figure 1;

Figure 3 is a side elevation of a wire electrode conductor carrying a glass bead;

Figure 4 is a longitudinal section of the base and conductor wires assembled in a die to show how the wires are fused to the disc;

Figure 5 is a top view of the finished base as- Figure 6 is a section taken on line 66 of Figure 5.

Referring to Figures 1 and 2, the glass disc or base comprises a circular disc i 0, to the centre of which is sealed an exhaust tube H. Around the periphery of the disc are a number of rounded slots I2 having depressed edgesor rims it. This form may be produced, for example, by taking a plain circular disc, heating it sufficiently to soften the glass, and then pressing suitable wires (or the like) inwards and downwards from the edge of the disc. This produces rounded slots of the kind shown. The disc may, however, be formed in other ways, such as in a moulding tool.

Figure 3 shows one of the electrode conductors.

. It comprises a-metal wire or rod M having fused thereon a small glass bead l5.

The method of sealing the wires to the disc according to the invention is shown in Figure l. A lower die 16 is provided with a central channel for the exhaust tube H and with a numb-er of smallerblind holes i1 arranged around a circle,

inthedisclll."

The disc It] is placed on the lower die l6 with the exhaust tube Ii inserted into the central channel of the die, the slots l2 registering with the holes H. The Wires M are then inserted in the holes I! with the beads l5 located in the slots l2. An upper die [8 having holes l9 corresponding to the holes I! is provided. Heat is applied in any convenient manner to melt the glass of the disc, and the upper die is brought down onto the disc, as shown in dot-dash lines it, with the upper ends of the wires M in the holes is. The glass is pressed into contact with the beads i5 and fuses thereto, and some is expelled sideways forming a ridge or heading 20. During this operation a roller tool 2| with an appropriately shaped groove 22, is run around the edge of the base ill to form the beading 20, and to ensure that the slots are closed up and that the melted glass flows all around the beads l5, so that there is formed a complete circular disc with the wires sealed through it, as shown in Figures 5 and 6.

The base assembly so formed is suitable for and located so as to correspond with the slots 12 any electric device having electrodes inside an envelope. The electrodes may be mounted on the wires l4, and the disc may then be sealed around the beaded edge to an appropriate envelope in any convenient way, and the envelope may be exhausted or filled with gas through the sealing to the material of the disc l0":

Furthermore, the exhausttube is not essential and could be omitted if a suitable-tube is'prjo- The head IS on each of the electrode conductors it should, of course, be of fusible materialappropriate for" vided somewhere else in the envelope of the:

device. the lower die would not be necessary.

What is claimed is:

1. The method of making a base assembly fer an electric discharge tube which comprises 10-- cating conductor wires in peripheral slots of a disc of fusible material;v softening thex-disc: by heat, squeezing the disc to press the disc into contact with the wires,v and applying a' rolling action around the edge of the disc in? such :a

manner as: to close" the slots" around the: wires so that the" wires are hemieticallysealed in the disc t 2; The method'of makingla base assembly for eatinga number: ofconductor: wires each provided with a fusible' bead in spaced. peripheral slots in a disc: of fusible: insulating: material; so that the b'ead's register within the: slots applw in'g heatto melt the fusible material;- pressing the disc into contact with the beadsandztoexe pel a peripheral ridge" oithe fusible material, and applying a rolling action around thetri'cl'ge of the disc to' form the ridge and: tb press the molten insulatingmaterial: inwards s'o'as to close the slots aroundithe-b'eads'.

3; The method of making a: base" assembly' for an?electricdischargetube which comprises form ing a plurality of spaced slotsaround the periphery of a disc of fusible material holdin'gaip1urality of conductor wiresinfixed relation to each other and to the disc with the wires extending In such a case the central channel of through the slots, heating the disc to fusing temperature, and squeezing the disc to press the fusible material around the wires in the slots and simultaneously rolling the rim of the disc to force: the fusible material around the Wires and to produce a-uniformi rim: around said disc.

4. The method of making a base assembly for an electric discharge tube which comprises fusing spaced slots with depressed rims into the periph'eryi-ofiadisc; holding a plurality of conduct'or'wiresin spaced fixed relation with each wire extendingg through one of the slots of said discsheating: said; disc to fusing temperature,

"aind pressing: said: disc and simultaneously rolling the fusible material around the rim of said disc tq jorce such. material around said wires 'a'n electric' discharge tube, which: comprisesv '10- Y and produces, uniform circular rim.

5, The method of making a base assembly for an' electric discharge tube comprising placing a number of conductor wires in peripheral depressions: located: in a: discof insulating: material, heatingthe disc and applying pressure on the disc to force the insulating materialzinto contactwith the wires, and applying pressure around; the'pe* ripheraledge. of the disc to forcethe insulating material into sealedcontactwith the wires.

r STEPHEN! 'JQHN POWERSi V REFERENCES CITED;

, 'I he following references are of record" in the file of this patent: i

UNITED STATES PATENTS Number Name Date '850;02'9- Meeker :Apr: 9', 19107 872530 Meeker: D'ec.i3; 1907 2395, 183 Franks Apr; 2', 1940 23345784 Miller: Nov.:23, 1943 21339350 Goodale Jan. 25,-.1944

23403879 Horn-N -Feb. 8; 1944 v FOREIGN. PATENTS Numberv Country Date:

376,953: Italy l. e -Dec. I4, 1939

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