US1560911A - Vacuum tube - Google Patents

Description

Nov. 10, 1925.

C. F. M., HAYES ET AL VACUUM TUBE Filed Feb. 10, 1925 Patented Nov. 10, 1925.

UNITED STATES PATENT OFFICE.

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VACUUM TUBE.

Application filed February 10, 1925. Serial No. 8,222.

To all whom it may concern:

Be it known that we, CHARLES Fnnonnrc MARCHANT HAYEs and Lnsnm GRINSTEAD, British subjects, and residents of Nightingale Lane, Balham, London, S. 'W. 12, England, have invented certain new and useful Improvements in Vacuum Tubes (for .which we have filed an application in England, dated 3rd May, 1924), of which the following is a specification.

This invention relates to thermionic valves or electron discharge tubes and is particularly concerned with the support or fixing of the electrodes, particularly the grid and anodes of'thermionic valves and is especially applicable to the construction of large valves such as are used fortransmitw ting purposes although it is in no sense limited to transmitting valves.

According to the invention, a band of metal is placed in position embracing a reentrant tube or stem of the valve bulb and carries the electrode in question by means of a number of legs and is ultimately fixed in position by the insertion of wedges which may comprise separate members, or may be formed by the ends of the electrode legs. The wedges or legsmay be fixed in position either by spot Welding at a number of points to the embracing band or in the case of the legs serving as wedges, wires may be welded to theleg and to the band and the former retained in position by twisting the two wirestogether. In order that invention ma be clearly understood and readily carrie into effect, some forms of construction for fixing electrodes in position in accordance with the invention are illustrated. in the accompanying drawings, in which I Figure 1 is an elevation of a complete thermionic valve with the walls of the bulb in section, showing both the anode and grid secured in position in accordance with the present invention; s Figure 2 1s a perspective view of one stem of the valve shown in Figure 1 but without the supporting legs attached to the clip;

Figure 3 is a'horizontal section on the line III-III of Figure 2, but in an intermediate stage of construction, wherein the welded edges of the clip are not turned down against the outer wall of the clip; and

Figures 4: and 5 are views similar to Figure 2, but showing two alternative constructions wherein the legs of the electrode form the securing wedges.

Referring first to Figures 1 to 3, a metal band a is placed in position around the glass stem or re-entrant tube 6 which is sealed into the walls a of the valve at one end. As can be seen the metal band forms a ring which does not fit the foot I) but leaves a free space. This is particularly clearly seen in Figure 3. The meeting edges (1, e of the band a are turned radially outwards so as to lie in contact as clearly seen in Figure 3 and are then spot welded together at a number of points as indicated at f in Figure 2., The out-turned edges (1, e can be left projecting radially as in Figure 3, but in Figures 2, 4 and 5 they are shown as folded down into contact with the outer cylindrical surface of the metal band a. In this condition the band forms a complete cylindrical ring entirely surrounding the stem or reentrant tube 6, but, as already mentioned, it is of such a size that it does not grip the foot I). It is subsequently fixed in position by one or more metal wedges g, there being actually three of such wedges in Figures 1 to 3 of segmental section. They are slipped in between the metal band a and the glass stem 6 and aresecured in the example illustrated by spot welding at the points h, although if desired other methods of securing may be employed. In Figure 1 this method of securing the anode is shown at the bottom of the valve and a similar method is shown at the top of the valve for securing the grid Z. In both cases in Figure 1 the legs m are shown secured to the metal band a by being spot welded on the outer surface of this band. The legs may, however, in

fact be made integral with the band a or may be riveted thereto.

As alread indicated, in Figures 4 and 5 I the legs m t emselves serve as the securin wedges, but. otherwlse the construction is similar to that shown in Figure 2 and similar .and electrodes therein,

reference letters have been applied. There are a number of ways of maintaining the legs in position when they serve as the wedges, for example in Figure 4 they are secured in position by spot welding as indicated at n. In the alternative form in Figure 5, however, each leg on has a wire 0 welded to it at a point a short distance away from the upper edge of the metal band a and the band a has a wire 7) for each leg welded to it at a point in the neighborhood at which the end of the leg m enters the band a. The wires 0, p are twisted together in pairs as shown in Figure 5' in order to hold the respective legs firmly wedged within the band a. In Figure 5 spot welding is also indicated for securing the legs in posit-ion at a, but the method of securing by the wires 0, p can be employed without spot welding at a without departing from the scope of the present invention.

Having thus described our invention what we claim as new and desire to secure by Letters Patent is 1. In a vacuum tube having an envelope and electrodes therein, the combination of a bandloosely encircling a stem on said envelope and supporting one of the electrodes, and a wedge inserted between said band and said foot.

2. In a vacuum tube having an envelope and electrodes therein. the combination of a band loosely encircling a stem on said envelope and supporting one of the electrodes, and a plurality of wedges spaced around the stem and inserted between said band and said foot.

3. In a vacuum tube having a envelope and electrodes therein, the combination of a band loosely encircling a stem on said envelope and supporting one of the electrodes, and a wedge inserted between said band and said stem and welded to said band.

4. In a vacuum tube having an envelope an electrodes therein, the combination of a band loosely encircling a stem on said envelope and supporting one of the electrodes, and a plurality of wedges spaced around the stem and inserted between said band and said stem, said wedges being welded to said band.

5. In a vacuum tube having an envelope and electrodes therein, the combination of a band loosely encircling a stem on said envelope and an electrode supported on legs, said legs being inserted between said band and said stem to act as wedges to secure said band in position.

6. In a vacuum tube having an envelope the combination of a band loosely encircling a stem on said envelope and an electrode supported on legs, said legs being welded to said band between the band and said stem, and acting as wedges to secure said band in position.

7. In a vacuum tube having an envelope containing grid and anode electrodes and furnished with two re-entrant stems disposed at opposite ends of said envelope, the combination of a band loosely encircling one of said stems and supporting said grid electrode, wedges inserted between said band and said stem,a second band loosely encircling the other of said stems and supporting said anode, and further wedges inserted between said second hand and said second named stem.

8. In a vacuum tube having an envelope with two re-entrant stems disposed at opposite ends of said envelope, thecombination of a band loosely encircling one of said stems, a grid electrode with integral legs, said legs being inserted between said band and said stem and acting as wedges to secure said band in position, a second band loosely encircling the second of said stems and an anode with integral legs, said legs bein inserted between said second hand and sai second stem and acting as wedges to secure said second hand in position.

9. A method of mounting an electrode within a vacuum tube envelope with a reentrant stem which consists in bending a metal strip to form a band loosely encircling said stem and having two radial flanges in contact with each other, spot welding said adjoining flanges together, thereby forming said strip into a continuous band and driving in a wedge between said band and said stem to secure an electrode to said stem.

10. A method of mounting an electrode within a vacuum tube envelope with a 'reentrant stem which consists in bending a metal strip to form a band loosely encircling said stem and having two radial flanges in contact with each other, spot welding said adjoining flanges together, thereby forming said strip into a continuous band, turning down said flanges to lie circumferentially against said band and driving in a wedge between said band and said stem to secure an electrode to said stem.

11. A method of mounting an electrode with integral legs within a vacuum tube envelope with a re-entrant stem which consists in bending a metal strip to form a band loosely encircling said stem and having two radial flanges in contact with each other, spot Welding said adjoining flanges, thereby forming said strip into a continuous band, and inserting thelegs of said electrode between said band and said stem to wedge said band upon said foot'and thereby to secure said electrode firmly in position.

12. A method of mounting a grid electrode and an anode within a vacuum tube envelope having two re-entrant stems at opposite ends which consists in bending two metal strips to form each into a band loosely encircling one of said stems and having two radial flanges in contact with each other, spot welding the flanges of each band together, thereby formin each of said strips into a continuous ban and inserting between the ,one band and the one stem the legs of the gria and between the other band and the other stem the -legs of the anode to act as. wedges and to secure said electrodes respectively firmly in position.. I

In witness whereof, we hereunto subscribe our names this 1925.

' CHARLES EREDERIC MARCI IAN'I' HAYES.

LESLIE GRINSTEAD.

29th day of J anuary, A. D.

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