US2309973A - Electron discharge device - Google Patents

Description

Feb. 2, 1943. c. F. MILLER 2,309,973

y ELECTRON DISCHARGE DEVICE riginal Filed May 2e, 1937 Tini-1E' .CM-J@ Patented Feb. 2, 1943 ELECTRON DISCHARGE DEVICE Carl F. Miller, Corning', N. Y., assgnor to Sylvania Electric Products Inc., a corporation of Massachusetts Original application May 28, 1937, Serial No. 145,198. Divided and this application October 22, 1940, Serial No. 362,194

2 Claims.

This invention relates to electron discharge devices and more particularly to improved contact bases for radio tubes and the like.

An object of the invention is to provide an improved form of contact base which can be applied either to me-tal envelope tubes or toI glass en- Lvelope tubes,

A feature of the invention relates to an improved form of shell base for radio tubes and similar articles.

Another feature relates to a radio tube of the type having a locating boss or projection on its base, and wherein the contact prongs are directly sealed into a glass header or closure member. Y

Anotherlfeature relates to an improved contact base for radio tubes and the like having a metal boss or locating member for preventing insertion of the tube in a socket in the wrong contact relation. Preferably this metal boss is located so that it also acts as an electrostatic shield between certain of the Contact prongs.

A further feature relates to an improved type of composite metal-glass radio tube or the like.

Other features and advantages not specifically enumerated will be `apparent after a consideration of the following detailed descriptions an the appended claims. i

Inasmuch as the present invention is concerned primarily with the envelope, shield and base portions of a radio tube or similar device, the electrode assembly or mount portion and the particular means for supporting the same within the tube are shown merely in outline form. In the drawing,

Fig. 1 is a vertical view, partly in section, of my improved form of shell type contact base for a glass envelope tube.

Fig. la is a bottom plan view of Fig. l.

Fig. 2 is a vertical sectional view showing my improved base applied to a metal Ienvelope tube.

Fig, 3 shows a modification of the shell base of Fig. 1.

Fig. 4 is a bottom plan view of Fig. 2.

Referring to Fig. 1, the numeral I represents a glass enclosing envelope of any well-known type, having supported on the interior thereof any form of electrode assembly or mount designated generally by the numeral 2. Merely for purposes of illustration the envelope is shown as of the domeshaped type having sealed therein a reentrant stem 3 terminating in a press 4 through which are sealed the various lead-in and support wires for the electrodes of the mount, these lead-in wires being contacted to the respective contact prongs 5, 6. While the drawing shows only two of these contact prongs it will be understood that a greater number will be employed depending upon the number of electrodes in the mount. Thus the lead-in wires 1, 8, for the plate and grid electrodes for example, are shown connected to the prongs 5, 6. Likewise the leads l), I0, for the cathode filament or heater will be connected to similar prongs; `and the lead II for the cathode sleeve will also be connected to its individual prong.

The base is in the form of a cup-shaped metal member I2 the upper rim of which is adapted to engage the shouldered portion I3 of the bulb,

the base being held fast in place in the customary manner by a layer i4 of cement. The bottom of the cup-shaped .base is provided with a series of circular openings I5, one for each of the contact prongs, it being understood that the openings I are much larger than the outermost diameter of the contact prongs so that said prongs can project through the said openings without being short-circuited.

Preferably the contact prongs are previously staked into a circular disc I6 of glass, ceramic or other insulating material and for this purpose each prong may be in the form of a small metal tube having integrally formed circular beads I1, I8, to engage the upper and. lower faces of the disc I6. Integrally fastened to the center of the bottom of the metal base is a hollow tubular metal boss I9 having an integral longitudinally extending rib or key 20. The boss I9 preferably extends downwardly beyond the contact prongs so that it may cooperate with a corresponding opening in a suitable contact socket whereby the tube is prevented from being inserted into the socket in any but the correct contact relation. The glass disc I6 with its contact prongs is held in place against the base of the metal shell l2 preferably by means of struck-out tongues 2| which are bent inwardly to rmly engage the upper face of the said disc. While the drawing shows two of these retaining lugs, it Will be understood that a greater or less number may be employed. The manner of connecting the various lead-in wires to the contact prongs is well-known in the art and detailed description thereof is not believed necessary.

The type of base described has the advantage that the contact prongs are carried as a unit by the insulator disc I6 and the boss I9 being of metal is capable of being welded to the .base 25 of member I2. Furthermore the boss I 9 being of metal and being interposed between the cont socket.

fore, they have been usually in the form of a Y molded insulating material and therefore are easily worn and in some cases sheared o when the tube is forced into the correspondingly keyed Furthermore these insulator bosses do not provide a conductive contacting means and being of insulation do not act as an electrostatic shield between the various contact prongs.

Instead of staking the contact prongs into a disc of ceramic, glass or similar insulating material, they may be molded'therein. In this case the insulator disc may be of Bakelite or other suitable moldable insulating material. Thus as indicated in Fig. 3 the prongs 5, 6 aremolded into a disc 23 of Bakelite which is also molded into the space between the contact prongs and vthe edge of the opening through which the contact prong passes, thus providing in effect a bead or bushing of insulation in which the Contact prong is supported and centered, this bushing being firmly attached to the base 25. In this embodiment, the boss i9 is preferably of hollow tubular metal and is welded or otherwise fastened to the disc 25 forming the bottom of cup I2.

The type of contact and keying base already described is also applicable to metal envelope tubes, as distinguished from glass envelope tubes.

Thus as shown in Figs. 2 and 4, the envelope 24 is of a metal usually employed in so-called metal radio tubes, such as steel or the like. The envelope is hermetically closed by a metal header 24a which is welded to the envelope 24. Header 24a carries a plurality of metal eyelets 24h through which are sealed, by means of the glass beads 241C, the various lead-in and support wires l-I I. Preferably, although not necessarily, the header Ella is in the form of an inverted cup which is welded around its periphery to the lower end of envelope 24. The contact base may be the same as that of either Figa 1 or Fig. 3, with the exception that thecylindrical part of the cup l2 (Fig. l) is omitted and the radial flange?! of the envelope 25s is welded, or brazed to the margin of the metal disc 25. Instead of joining the parts 25 and 21 by welding, the lower end of member 24 may be spun over the edge of disc 25. The insulator disc I6 in this embodiment is held in place by bent over lugs 26 struck out from the disc 25 and bent back over the edge of said disc as shown in Fig. 2.

This application is a division of application Serial No. 145,198, filed May 28, 1937 (Patent No. 2,238,025).

What I claim is:

1. An electron tube including a metal base member comprising a substantially flat central bottom with a surrounding perforated margin, the perforations being arranged in a symmetrical path around the center of the bottom, a central opening in said bottom closed olf on one side by a hollow metal tubular body depending therefrom, electrical conductors passing through said perforations, a mass of fusible material located in each perforation closing off the space between the conductor and the edge of the perforation, said insulating material being sealed vin a vacuum-tight manner to said edge and serving to support the conductor substantially centrally thereof. v v Y l 2. An electrical discharge device, having an envelope with a metal base comprising a central fiat portion surrounded by a series of symmetrically arranged perforations and having its outer periphery sealed in a vacuum-tight manner to an end of said envelope, a metal conductor positioned substantially centrally in each perforation and shaped at its outer end to serve as a plug-in pin, an electrode structure enclosed by said envelope and connected to said conductors, a mass of fusible vitreous material filling each perforation around the conductor therein and sealed in a vacuum-tight manner to the edge .of the perforation, said vitreous materialV having a portion of its mass extending through said perforation and supporting the conductor on one side of said flat portion around the margin of the perforation and another portion of its mass extending through the perforation and supporting the conductor on the Opposite side of said fiat portion around the margin of the perforation, a central opening in said central flat portion of the base and a hollow tubular metal keying conductively carried by said bottom and closing off said central opening.

CARL F. MILLER.

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