GB653324A - Improvements in or relating to electron discharge devices - Google Patents

Abstract

653,324. Thermionic valves. M-O VALVE CO., Ltd., FREEMAN, G. V. H., and WINDSOR, L. R. E. Feb. 17, 1948, No. 4638. [Class. 39 (i)] A method of manufacturing an electron discharge device includes the steps of mounting within the envelope a locating member provided with at least one aperture or recess, inserting in the envelope an electrode structure having at least two supporting members so that each of the supporting members enters an aperture or recess in the locating member whose area is substantially greater than the cross-sectional area of that supporting member, and manipulating the electrode structure until it is firmly located solely by the engagement of each of the supporting members with the periphery of the aperture or recess which it enters. The locating member may have the form shown in Figs. 2, 3 or 4. In Fig. 2, the member is provided with a central aperture whose diameter is preferably slightly less than the diameter of the circle on which the electrode-supporting members 4 lie. In Figs. 3 and 4 the aperture or apertures are arcuate in shape so that by rotating the electrode structure a firm engagement of the supporting members with the locating member may be obtained. The locating member may be of mica and the supporting members 4 may extend for an appreciable distance on the side of the locating member opposite to that on which the electrode structure is located. Alternatively the locating member may be of ceramic or refractory material and may be provided with recesses instead of apertures. The locating member is preferably provided with projections 11 which engage the envelope.