US2444082A

US2444082A - Flexible electrode support for electron discharge devices

Info

Publication number: US2444082A
Application number: US652927A
Authority: US
Inventors: Wood Ross
Original assignee: Raytheon Manufacturing Co
Current assignee: Raytheon Co
Priority date: 1946-03-08
Filing date: 1946-03-08
Publication date: 1948-06-29
Anticipated expiration: 1965-06-29

Description

R. WOOD FLEXIBLE ELECTRODE SUPPORT FOR ELECTRON DISCHARGE DEVICES Filed March 8, 1946 INVENTOR Ross W000 M June 29, 1948.

III/i/l/I/l Fla. 7

Patented June 29, 1948 I FLEXIBLE ELECTRODE SUPPORT FOR ELECTRON DISCHARGE DEVICES Ross Wood, Waltham, Mass, assignor to Raytheon Manufacturing Company, Newton, Mass, a corporation of Delaware ApplicationMarch 8, 1946, Serial No. 652,927

This invention relates to electron-discharge devices, and more particularly to the means by which filamentary cathodes are held in tension within the device.

A large number of devices for supporting filaments in tension within an electron-discharge device have been conceived but their use has been confined to electron-discharge devices of the well known conventional size. With the advent of sub-miniature electron-discharge devices such as are used in hearing-aid apparatus, pocket-size radio receivers and other electronically-operated devices where extreme compactness is a first requisite of construction, the importance of properly spacing and positioning the minute elements within these sub-miniature electron-discharge devices poses a very difi'icult structural problem, namely, means for properly maintaining a directly heated filament in proper space relation to the control grid within the confines of an extremely small envelope having an internal diameter '04 the order of 0.2 of an inch. Cantilever spring suspensions as ordinarily used in some miniature tubes, particularly those of a size somewhat larger than the present device, present many difiiculties when an attempt is made to use them in the sub-miniature type tubes. Such a cantilever structure when scaled down to meet the needs encompassed in a tube having a diameter as just described would, by reason of its diminishing size, lose itselastic characteristic which is so essential to maintaining and supporting a filament in tension.

It is therefore an object of the present device to provide a filamentary support which will have a cantilever spring action in the longitudinal plane of an electron-discharge device in contradistinction to a cantilever structure in the transverse plane as commonly used.

It is a further object to provide a support for a. filament which is a unitary structure capable of being deformed without acquiring a set in the deformed position,

These and other objects will present themselves as the specification progresses and as evidenced by the attached drawing in which:

Fig. 1 is a cross-sectional view of one embodiment of the invention; and

Fig. 2 is a second embodiment, in cross section, of the present invention.

Referring now more particularly to Fig. 1, the drawing illustrates an evacuated envelope I containing therein electrode spacers II and I2, composed of mica for example, which serve to position the anode electrode I5 within the envelope I0.

8 Claims. (Cl. 250-275) The spacers I I and I2 are provided with apertures I1, 23, 24 and 25 through which are threaded the filamentary cathode I4 and the filament support I3. For the sake of clarity'the usual control grid has been omit-ted. However, the device can be used in combination with any number of electrodes.

The metallic support I3, which may be composed of tungsten for example, is rigidly aflixed, as by welding, to a metal tab 16 and extends on through the aperture I'I, said tab being in turn :fastened to the edge of insulating spacer I2 by crimping thereto, or by any other suitable means. The free end of support I3 extends through aperture 23 in spacer I I and terminates in a short arm ISA. The filament I4 has tabs 2!] and 2| amxed to each end thereof as by welding or other suitable means. The talb 20 is welded to the end of the short arm I3A of the support and the tab EI welded to the cross bar I8 which in turn is zfastened, preferably by welding, to the downwardly extending member I8A, said last-named member being riveted or otherwise firmly fastened to the spacer I2. The manner of asseming the support I3 and filamentary cathode It will be given in more detail hereinafter.

Electrically-conductive members I9 and ISA are firmly im beddcd within the press 22, said press being an integral part of the envelope Ill. The members I 9 and ISA serve to support the electrode assembly within the envelope I0 and to conduct current to the respective electrodes. Lead -I9' is welded to the cross memlber I8, said cross member acting as a support for one end of the filamentary cathode I4. Lead I9A is welded to the lower end of support I3 which projects through aperture I1. This assembly pro vides a path for the conduction of current through the, filamentary cathode I4 when a potential is applied between the leads l9 and ISA.

In the construction of the device, the length of the filament I I is first determined. Tabs 20 and 2! are then welded to the respective ends of said filament. Tab 20 is then welded, or otherwise :fastened to the spring arm I3A. Now ta-b 2| is dropped through the

apertures

24, 25, spring arm I3A is depressed and tab 2I welded, to the cross member I8. This arrangement causes the support I3 to bow out or distort, and so provide the necessary tension in filament I 4. Thus we have provided a unitary supporting structure, simple in its configuration, small in that portion which must lie in the transverse position within the device, yet providing a tension arrangement which is so resilient that it will not take a set in the deformed position.

Fig. 2 illustrates a second embodiment of the present device in which the support is a flexible metal member 26, preferably composed of tungsten. This structure permits even greater latitude in reducing. the size of. the envelope l0. Its advantages will' be taken up as thisyspeciflcation progresses. In this particular embodiment, the tab 2! is fastened, by welding or otherwise, directly to the member I8A.

In Fig. 2, the short arm I3A is dispensed with to enable the construction of devices of the type described having still smaller'internal diameters. Here the construction of the support -26'is in the nature of a half-portion of a string and bow arrangement, the tab l6 being the pointof fulcrum. In this particular embodiment'the construction is simplified further by threading :the filament I4 through the

apertures

24 and 25 and fastening the tab zl directly tot-he member ISA, thusobviating theextended member l8. As can be readily observed the tension in the filament is similar to the tension in the string of a bow which has been pulled taut.

Although several embodiments of, this invention have been described and illustrated, it is of course understood that many -,modifications and alterations may be made wherein the relation of the electrodes maybe altered to achieve the primary conception of thisinvention; for example, a plurality of filament supports may be placed diametrically, opposite each other for the purpose of constructing a dual diode or triode having separate filaments within the small space as.

hereinbefore described, or such supports may be readily used in tubes of larger diameter with equal effectiveness.

What claimed is:

1. An electrode support comprising a flexible member of unitary construction, a major portion of the length of said member being substantially parallel with an electrode attached thereto, means for rigidly supporting one end of said .member, means for fastening said electrode to the unsupported end ofsaid flexible member, and

-means for rigidly supporting the opposite end of .said electrode to cause said flexible member to distort under-tension.

2. An electrode support comprising a flexible L-shaped member, means for rigidly fastening one end of an, electrode to one arm of said member, means for rigidly supporting the other arm of said member, and means forrigidly fastening the opposite end of said electrode to cause said member to distort under tension.

3. An electrode support. comprising a flexible -S a-ped member having arms of substantially differing lengths, means for rigidly fastening one end of an electrode to the shorter arm of said member, means for rigidly supporting the end of the longer arm of said member, and means for rigidly fastening the opposite end of said electrode to cause said member 'to distort under tension.

4. An electrode support comprising a flexible unitary L-shaped member having arms of substantially differing lengths, the longer arm of said memberbeing substantially parallel with an electrode attached to the end of the shorter arm,

4 thereof, means for rigidly fastening one end of said electrode to the end of the shorter aim of said member, means for rigidly supporting the end of the longer arm of said member, and means for rigidly fastening the opposite end of said electrode to cause said member to form a bow under the tension. c

, 5. In an electron discharge device, the combination of an envelope containing an electrode assembly, insulating spacers having apertures therein for the passage therethrough of said electrodes, at least one of said spacers having a metal tab attached to the edge thereof, a second metal tab attached to said first-named spacer, said second-named tab being disposed between said firstnamed tab and an, aperture in the center of said spacer, an electrode support comprising a flexible metal member, a major portion of the length of said member being substantially parallel with an electrode attached to one end thereof, the opposite end of said member being rigidly affixed to said first-named tab, andthe other end of. said electrode being attached ,to said second-named tab to cause said support to distort under tension.

6.. In an electron discharge device, the combination of an envelope containing electrode spacing means, at least one of said spacing means having means for rigidly attaching thereto at least one electrode, said spacing means .having apertures therein for the passage therethrough of, said electrode, an electrode support comprising a flexible unitary ,member, a major portion of the length of said support being substantially parallel with an electrode attached thereto, said support being rigidly attached to a first of said spacing means, the free end of said support extending through an aperture in a second of said spacing means, and means for attaching said electrode to the free end of said support, the opposite end of said electrode being firmly afiixed to said first-named spacing means to cause said support to distort under tension.

.7. An electrode support comprising a unitary member having arms of substantially difiering lengths, the shorter of said arms being relatively rigid with respect tothe longer of said arms, means "for attaching one end of. anelectrode to the shorter arm of said member, andmeans for one end ofqan electrode to the shorter arm of said member, and means for attaching the opposite end ,of said electrode to cause said longer arm to distort under the tension.

ROSS WOOD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,042,554 Round June 2, 1936 2,266,080 Rockwood Dec. 16, 1941