US1721405A - Electrode for vacuum tubes - Google Patents

Description

July i929. D. A. MULLANEY Er Ai. L7219405 ELECTRODE FOR VACUUM TUBES Filed July 8, 1925 A w f,

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i U o T DJ Patented July 16, 1929.

UNITED STATES 1,721,405 PATENT OFFICE.

DUDLEY A. MULLANEY AND JOHNSON F. HENDRY, F SCHENECTADY, NEW YORK, 'i

ASSIGNORS TO GEN EBALELECTRIO COMPANY, A. CORPORATION 0F NEW YORK.

ELECTRODE FOR VACUUM TUBES.

v application 111mlv mi a, 1925. serial No. 42,274.

Our invention relates to improvements in electrodes for vacuum tubes, and more particularly to methods of constructmg and supporting the grids and anodes used 1n such 5 devices.

It is the object of our invention to provlde an electrode structure which shall notonly be light and rigid but the parts of whlch will be symmetrical and consequently adapted for rapid assembly in jigs, and fixtures so as to reduce manual assembling operations to a minimum. i

In the manufacture of anodes and grlds for space current devices, particularly of the t-ype known as power tubes 1n which the electrodes are of considerable size, it 1s customary to use heavy rods ofA molybdenum or tungsten for supporting the electrodes. These are usually riveted to the electrode body itself and either welded or riveted to metal straps by means of which the assembled structure 1s clamped to some lass member of the tube,

usually the stem t rough which the lead-in wires pass. D

In accordance w1th our 1nvent1on we use a lighter but equally rigid structure for uniting the parts Vof such electrodes as well as for holding the samev in position in the tubes.

The structure is shown in detail in the annexed drawing in which:

Fig. 1 shows ourl improved supportmg structure as applied to an anode of a space current device.

Fig. 2 illustrates this applicatlon to a grld or control electrode, and

Fig. 3k depicts a complete space current device embodying the improved electrode of our invention whi e Fig. 4 is a detail of an anode.

The improved structure of the invention is applicable to different types of electrodes so that both anode and grid may, for example, be built alon the same general lines.

Referring 1n detail to the drawings it will be observed that the anode support of Fig. 1 is made from flanged or channel members 1,-2, preferably rolled or stamped from sheet molybdenum or other suitable metal. These are attached to the anode sections, preferably by riveting although they may be spot welded in place if desired. Each channel member has welded or riveted to it at the end opposite the anode one-half 5 or 6 of a metal clamp. The two halves when placed together are adapted to embrace the glass stem 30 or 34 of the tube ina manner shown in Fig. 3 where a portlon of such a clamp is visible. `For this purpose, the clamps are provided with holes 7, 8, 9, 10 for the reception of screws which are indicated in Fig. 3.

Fig. 4 illustrates a detail of the anode y structure showing -a method of constructing the anode in question'so as to secure substantiallythe same bracing effects of the channel members 1 and 2 and thus additional strength. In this case, the anode is composed of flat members 3, 4, 11, 12 provided with flanges 13 by means of which the members 1 may be assembled by riveting or welding as desired.

Fig. `2 illustrates the application of the channel supports to the construction of a grid or control electrode. In this case the flanged or channel members are represented by 14, 15. These are attached to clamp members 5 and 6 in the same manner as the anode of Fig. 1, the clamps in this case serving the same purplose heretofore 'described for the anode.

T e gridwire 17 is wound over the channel members, the latter being wide enough so that the resulting cage will accommodate the filament or cathode which is shown at 18. The upper portions 'of the channel members 14, 15, are held together by means of bar 19 made of suitable insulating material such as fused quartz which is embraced and held by theends of the channel members in any appropriate way. This bar serves as a support for the cathode and wires 20 may be imbedded in the quartz and used to hold the cathode supporting system which comprises insulating members 21 preferably made of fused quartz, spring 22 and retaining hooks 23. f

Other metal supporting members may be held by the quartz cross-piece 19 to aid in keepin the elements of the tube rigid. Thus, the en 24 of the leading-in conductor 32 which is sealed into the press 25 may extend beyond the press and rest in a bearing hole in the quartz bar 19. This facilitates assembly since the anode and cathode may be rapidly and accurately brought into their relative juxtaposition and rigidly held in place.

A conductor 33 may be wrapped around the wire 32 in any suitable manner and attached to one of the electrodes of the device, for example, the anode, and thus serve to connect the anode with the terminal 27.

Figure 3 shows the method by which the electrode and supports are disposed in a 11o s ace current device of the power tube type.

he tube consists of a glass container 26 a A portion of which is shown broken away. The anode 11 is also shown broken away in order to expose the rid and cathode whose structure has been escribed in detail above. The

-cathode leading-in wires are indicated by 31, embedded in aA lass press around which is clamped the gri support composed of clamp members 5, 6. The'lament conduc-K tors are brought out to terminal posts only one of which, 29, is shown, while the grid is connected to ost 28 which together with bers of which only system described above is very rigid, easily reduced and readily assembled. 1t is less iableto warp out of shape under the stresses produced by the heat evolved during the operation of the tube and presents the further advantage ofbeing adaptable to quantity manufacture and assembly in machines and 310s.

bWhat we claim as newand desire to secure by Letters Patent of theUnited States, 1s:-

. 1. A space current device comprising a container of insulating material, a reentrant glass tube at each end of s aid container, an Vanode mounted on one of said reentrant tubes and a grid mounted on the other reentrant tube,rthe su ports of both anode and grid comprising anged members metallically attached to and extending along the entire 1ongitudinal axis of the surface of said anode and grid, said anode and grid being provided with clamp members adapted when coacting with each other to embrace said respective reentrant glass tubes.

2. In a space current device, an anode com'- prising a plurality of alternately arranged iat and round ortions provided with flanges which extend 1n a direction normal to the surfaces of said portions at their edges, said flanges being secured together to form a rigid body of closed perimeter, and means for supporting the anode within the device, said means comprising a pair of oppositely disposed channel members secured to said flat anode portions.

3. In a s ace current device, a grid comprising a pllilrality ofupright channel members about which the grid wire is Wound, a clamp secured to one end of the channel members for supporting the grid within the device, .the opposite end of said members being spaced by an insulating material which is adapted to constitute an electrode support.

4. 1n a space current device, an evacuated envelope provided with a reentrant stem a combined filament and grid electrode arrangement comprising a pair of upright channel members about which the grid wire is wound, said members being spaced by au linsulating material at one end and terminating in a clamp at the other end which embraces said stem, a filament suspended between the insulating material' and said stem. Inwitness whereof,;we have hereunto set our hands this 7th day of July, 1925.

' -DUDLEY A. MULLANEY.

JOHNSON F. HENDRY.'

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