US2298929A - Electron discharge device - Google Patents

Description

H. J. DAILEY ELECTRON DISCHARGE DEVICE Filed Nov. 29, 1941 w Sa Q INVENTOR H. J Ey ATTORNEY Pa'tented Oct. 13, 1942 ELECTRON DISCHARGE DEVICE Hampton Jennings Dailey, Bloomfield, N. J., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application November 29, 1941, Serial No. 420,908

6 Claims.

This invention relates to electron discharge devices, and more particularly to supports used therein and having applicability especially to electrode support and tensioning at the bight portion of a filament.

The prior art is replete with electrode supports of which many apply tension to a filament. Most common amongst these is the simple bight-engaging hook formed as the outer end of a single resilient wire arm. The arin is deflected under tension or normal length of filament and tends to lessen its deflection as the filament elongates from heat or otherwise but within a range of tensioned movement to keep the filament taut. A drawback is present, however, in such'a construction, namely, that the wire arm is also flexible laterally of the filament to the same extent as flexible lengthwise of the filament. Such a circumstance becomes intolerable as use is made of the resilient support in electron discharge devices the sensitivity of which is essentially important, as, for instance, in electrometer tubes, of which one identified in trade as Westinghouse RH 507 is an example.

An object of the present invention is to provide an improved tensioning hook which is readily applied.

Another object is to provide a tensioning hook which will exert its tension in a proper direction and maintain proper positioning of the filament.

A further object of the invention is to prevent the tensioning hook from material lateral deilection.

A still further object of the invention is to obtain more accurate location and retention of a filament with respect to other electrodes.

Other 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. f

In the accompanying drawing, wherein like numerals of reference indicate similar parts throughout the several views;

Figure 1 is an elevation of a discharge device with part of the envelope broken away for better disclosing my invention therein;

Figure 2 is a vertical sectional view on line 1li-II of Fig. 1;

Figure 3 is a cross-sectional view on line III-III of Fig. 1; and

Figure 4 is a perspective View of the hook member and its mounting constituting the essence of the present invention.

In the specific embodiment of the invention i1- lustrated in said drawing, the reference numeral II) designates a typical radio tube evacuated envelope to which is sealed a reentrant stem ll having a press l2 at its inner end. 'I'he press is employed as usual for sealing therethrough or therein the various lead-in and support wires I3 to l1, inclusive. For purposes of explanation, the tube here shown will be described in its upright position to assist in location of various parts, and considered with the stem projecting upwardly inward from the bottom of the tube.

The particular tube shown is of the triode type, comprising a filamentary hairpin cathode I8, a attened helical wire grid I9 and a substantially rectangularanode 20 having usual positions and relation to each other. The grid I9 is formed with a pair of parallel uprights or side rods 2|, 2l, the lower ends of which are integrally connected by a horizontally disposed U-shaped connecting portion 22. At the middle of this connecting portion 22 is Welded or otherwise secured one wire 23 of a crowfoot, which, as part thereof, has two other or outer wires 24, 24 on opposite sides of the middle one 23. The upper ends of these two outer wires bend outwardly and are secured to the lower ends of side rods 25, 25, in turn carried between flanges 25, 26 at the sides and longitudinally of the anode. The upper ends of these several side rods are similarly rigidly secured, except that it is more convenient to weld the horizontally disposed U-shaped connecting portion to straight ends of the grid side rods after the same have been inserted through the anode. Thus assembled, the said side rods 2l, 2l of the grid are braced and supported next their upper ends by the horizontally disposed U-shaped portion 22', the legs of which are welded to upper ends of the side rods.

A central depending wire I5 is welded to the U-shaped connection 22 and at its lower end is imbedded in the portion of an upper crowfoot which constitutes the glass or other ceramic body thereof. On opposite sides of this central wire in the body of the upper crowfoot are two outer wires 24', 24 which bend laterally and are welded at their upper ends to the upper ends of the anode side rods 25. The construction obtains a marked rigidity of anode with respect to the grid. It may be here noted that the body of each crowfoot provides sleeves 21 of glass or other seramic extending upwardly around the several wires out of engagement therefrom for purposes of increasing the surface path between the wires and preventing leakage therebetween across the glass or other ceramic surface. In the use made of the particular tube being described, the part described as the anode is made negative with respect to the part described as a grid, and ace cordingly the part described as the anode is actually functioning as a grid and requires dielectric insulation to a greater extent than the usual anode.

The filament or cathode is preferably of the hairpin type providing legs in a vertical plane with the lower ends of said legs secured to leadin wires l, i6 and having its upper end or bight 28 carried by a hook member 29 constituting an essential part of the present invention. For supporting the said hook member, the Wire I5 protruding from the middle of the press constitutes a supporting rod having no external connection through the press. Said rod l5, as may be seen clearly in Figure 2, projects upwardly out of the press, and is oset rearwardly ther'eabove before reaching the anode so as to clear the anode, and then extends upwardly past and beyond the anode where it is given a forked construction in some suitable manner. The particular forked end, as shown in Figures 1 and 4, is obtained by offsetting, in a plane parallel to the anode, an upper end portion 30, by providing a supplementary part or end portion 3l similarly but oppositely offset in the same plane and by having a short lower end 3 I of the supplementary part contiguous to the rod l5 below the offset portion thereof and welded thereto. If so desired, the upper end of this forked rod may be and preferably is braced from one of the other electrode supports. Inasmuch, las indicated above, the anode is intended to function as a grid vin lthis particular tube, it is preferable to avoid dielectric leakage therefrom to the forked filament support, wherefore I prefer to brace the filament support from the electrode above described as the grid i9. Braces 33 having dielectric beads 34 interrupting the electrical continuity thereof are welded at opposite ends to the forked ends and to the upper end of the grid side rods. These braces accordingly accurately position the filam-ent supporting rod with respect to the grid.

Hook member 29 is here shown as a twostrand or doubled wire, the doubled end 3'2 Vof which constitutes the prong of the hook vfrom which the two strands dip side by side and return upwardly side by -side to form the bightsupporting portion 32 at the bottom of the dip. The two strands of the hook member are then bent laterally or horizontally at a position above the bight-supporting portion in a direction `away from the prong, and for added rigidity may be spot-welded or otherwise secured together in the region of this horizontal projection away from the bend. The strands constituting this horizontally projecting portion are spread or caused to diverge rearwardly and engage against the forked ends 3u, 3i of the filament supporting rod l5, being welded thereto at the points of contact. By virtue of the divergence of the strand portions 35, 35 the hook member is braced against lateral deflection, which the hook will perform is a resilient up and down movement in response to the tension of the filament. The fact that the strands forming the hook have a contiguous region and are secured together in that region, the hook portion of the hook member presents considerable rigidity against flexing in any direction which 'accordingly restricts the resilience of the hook member to the fieXing which may occur in the divergent'portions of the strands. Since the diverging strands brace each other in the common plane of the strands, it will now be evident that the only'direction of flexing will be in a direction normal to said plane of the diverging strands which is a direction longitudinal of the filament. The mounting of the F lament is thereby maintained accurate withrespect to the other electrodes sothat the device and virtually the only movement is usable in highly sensitive work such as required of electrometer tubes.

Since the various details of construction, as well as the precise relation and functioning of parts, are subject to variation and change without departing from the inventive concept or scope of the invention, it is intended that all matter contained in the specification or illustrated in the drawing, shall be interpreted as exemplary and not in limiting sense. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein shown and described and all statements of the scope of the invention herein set forth as a matter of language which might be said to -fall therebetween.

I claim:

l. A resilient support for tensioni-ng a lament, comprising a hook member having `a filament engaging portion of double wire terminating as a prong and having resilient portions diverging from the double Wire portion remote from the prong in a plane normal to the direction of tensioning of the filament.

2. A resilient support for tensioning a filament, comprising a hook member of which the hook portion consists of a plurality of contiguous strands reenforcing one another, said strands separating away from the hook portion thereby permitting iiexing thereat in one direction and more rigidly preventing flexing transverse thereto.

3. A resilient support for tensioning a 1i-lament, comprising a hook member of which the hook portion consists of a plurality of contiguous strands secured together and reenforcing one another, said strands separating away from the hook portion thereby permitting fieXing thereat in one direction and more rig-idly pre-venting flexing transverse thereto.

4. An electron discharge device having a filament therein bent with a bight portion, a hook member supporting the lament at Vsaid bight, and a relatively rigid forked support, said hook F member having diverging portions secured tothe forked parts of said nforked support.

5. An electron discharge device having a filament therein with a bight portion and depending leg portions ina vertical plane, a hook member engaging said yfilament at vthe said bight portion, said hook member having diverging strands therefrom situated in -a plane transverse Vto the said vertical pla'ne of the filament and thereby bracing the hook laterally with respect to said vertical plane.

6. An electron discharge device having a lilament therein with a bight portion and depending leg portions in a vertical plane, a hook'member engaging said -la-mentat the said bifghtportion, and a relatively rigid `forked support the forked ends of which-are in a plane substantially parallel to said vertical plane of the filament legs, said hook member having diverging strands therefrom in a plane transverse to both of the aforementioned planes, said strands having outer end portions thereof each `secured respectively to one of the forked ends 4of the forked support and thereby bracing the hook against `flexing in the said transverse plane and permitting flexing in a vertical direction.

HAMPTON lJntfNilvofs BAILEY.

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