Патент USA US2115934код для вставки
May 3, 1938. N. R. SMITH 2,115,934 ELECTRODE MOUNT Filed Dec. 51, 1936 INVENTOR NEWELL R. SMITH V %C ATTORN EY % Patented May 3, 1938 2,115,934 UNITED STATES PATENT OFFICE 2,115,934 ELECTRODE MOUNT Newell R. Smith, Bloom?eld, N. J., assignor, by mesne assignments, to Radio Corporation of America, a corporation of Delaware Application December 31, 1936, Serial No. 118,523 5 Claims. (Cl. 7250-27-5) My invention relates to electron discharge de vices, particularly to electrode constructions and their mount assemblies. Minimum spacing of ‘electrodes of a mount in I a tube with the usual tensioned ?lamentary cath ode is limited by the room required for the cath ode which, because of its ?exibility, is free inter mediate its ends to vibrate and to move consid erable distances. In power recti?ers, for exam 10 ple, it is important that the anode cathode spac ing be as small as possible to minimize the space impedance and permit greater anode current for a given anode operating temperature. Mounts employing the usual ?lament supporting means 15 are dif?cult to-assemble, particular pains being necessary to obtain a ?xed and uniform spacing between the ?lament and surrounding electrodes. An object of my invention is to provide a mount with a ?lamentary cathode and cooperating elec so trodes that may be easily‘assembled. A further object of my invention is to provide a mount with an anode and rigid self-sustaining ?lamentary cathode that may be closely mounted in cooperating relation. 28 ‘A further and more specific object 01' my in vention is to so form a?lamentary cathode with ‘ a'cross sectional con?guration that may lend sufficient rigidity to the cathode to prevent its vibration or movement between its points of sup 30 port. According to my invention, a ?lamentary cath ode and cooperating electrodes are so made that they may be mounted in close spaced relation ship, the ?lamentary cathode being stiffened to 35 make it self-sustaining in its supports, and the anode being so formed about the cathode to in crease the tube perviance. Ribbon-like strips of cathode material maybe longitudinally grooved by rolling or pressing, and the channelled ?la Figure 1 is a sectioned perspective view of one electrode assembly embodying my invention, Figure 2 is a detailed view showing the cross sectional con?guration of one form of channelled ?lament constructed according to my invention, and . Figure 3 shows another electrode assembly em bodying the characteristic features of my inven tion. The electron discharge device shown by way of example in Figure ‘1 and embodying the charac teristic features of my invention comprises an envelope I with a re-entrant stem 2, and press 3 insulatingly supporting the usual lead-in con ductors. The tube, chosen for illustration is shown with a glass envelope, although a metal envelope may be used, and with the electrodes of a full wave recti?er comprising anodes 4 se cured at their ends to insulating spacers 5 such as mica discs, the entire assembly being supported by the conductors embedded in the press. Each anode, according to my invention, com prises a single sheet of metal folded as shown with two longitudinal slots or folds 6 extending to wards the center of the tube to form indentations facing outwardly, the portions of the anode 1 ad jacent the folds being pressed in a cylindrical plane to present to the wall of the envelope a heat radiating surface of considerable area. The walls of the indentations may be accurately formed on a standard punch press machine to uniformly and closely space the sides of the in dentation. ‘ A ribbon-like ?lamentary cathode constructed according to my invention may conveniently be mounted in the slots with a minimum yet accu rately ?xed-spacing between the walls of the slot and the ?at sides of the cathode. Within each . slot is mounted a portion of ?lamentary cathode ment so constructed out to the proper length 8 shown in detailed section in Figure 2. The ?la and mounted in an electrode assembly. I have, ments, preferably strips of refractory metal such according to one embodiment of my invention, as molybdenum or nickel-iron-cobalt alloy, com bent the channelled strip at its center to form a mercially known as “16 metal”, are longitudinally 5 “V”, and welded the ends of the legs of the “V" grooved or channelled along the center of the to supporting lead-in wires in the press at the‘ ribbon or strip by-rolling or pressing to form the lower end of the tube so that the bight or apex strip with any desired cross sectional con?gura of the ?lament lightly engages at its edges, the tion. While the rectangular channel 9 shown edges of a narrow slot in the upper insulating in Figure 2 has been found to stiffen the strip sufficiently, the strip may be formed with any 50 spacer. V The characteristic features of this invention are de?ned with particularity in the appended claims and preferred embodiments are described in the following speci?cation and attached draw 55 ing in which; ' ' other desired cross sectional contour such for example as a semi-circle. In the particular em bodiment illustrated in Figure 1 each channelled ?lament is coated with an electron emitting coat ing such as barium-strontium-carbonate, is bent ‘to form an inverted “U”, the legs of the ?lament 2 8, 1 1 6,984 inserted in openings or notches in the upper insu lating spacer, and their lower ends attached by welding to current supply conductors with the transverse section at the top of the "U" bearing against the upper insulating spacer S to trans versally support it. With the open sided slots in the anode and the stiff ?lamentary cathode of my invention, the electrodes may be automatically assembled by 10 machines, eliminating the usual hand operations. A chuck, for example, may be inserted through the open side of the slot to guide the ?lament into place where it is welded, at its lower end, to current supply conductors. It has been found ll that a ?lament constructed and mounted as shown in Figures 1 and 2 is self-sustaining, re quires no sprlng tensiouing means, commonly ac cepted as being indispensable for ?lamentary cathodes, and is rigidly held in place by the two welds at the lead-in wires. The parallel faces of the ribbon-like ?lament and walls of the slots minimize the anode-cathode impedance of the tube and with the plane of the ?lament normal to the wall of the envelope electrostatic in?uences on the cathode. such as "grid efl'ec ” noticeable particularly in tubes with metal envelopes, is materially reduced. This construction is strik ingly simple when compared with the usual mount of this type, is easy to assemble, and in 30 expensive to manufacture. My ?lament has been successfully employed in a commercial tube known as the "80" when the ribbon ?lament is bent at its center to form a “V", as shown in Figure 3, the ends of its legs 36 welded to lead-in conductors l0 and its apex slid ably held at the edges of the strip in opening it constructed, the apex of the ?lament above the spacer may be ?attened to rest upon the bridge. Such a bridge would serve to prevent the apex of the ?lament from slipping through the opening and disengaging the spacer. Since many modi?cations may be made in this invention without departing from the spirit thereof, it is desired that this invention be limited only by the prior art and the appended claims. I claim: 10 1. Anelectron discharge device comprising an envelope, an anode in said envelope with a cylin drical surface concentric with the wall of the envelope and two elongated indentations extend ing lengthwise of said anode with the sides of said 16 indentations opening in the cylindrical surface of the anode facing said envelope, and a U-shaped ?lament of ribbon-like refractory metal, the legs of said ?lament being insulatingly supported in the indentations with the plane of the ribbon 20 like ?lament parallel to the walls of the slots. 2. An electron discharge device comprising an anode and a ?lamentary cathode, an insulating spacer, the anode and cathode insulatingly held in cooperating spaced relation, and the cathode com 26 prising a strip of refractory metal stiffened throughout its length with a longitudinal channel, the lower end of the stiffened cathode strip be mg ?xed and the other end of the strip being free to move longitudinally and slidably guided by 80 said insulating spacer. 3. An electron discharge device comprising an envelope, an anode in said envelope comprising a metal sheet, said sheet being folded to form an elongated indentation, the sides of said indenta 35 tion opening upon the wall of said envelope, an. in the insulating spacer. Any desired arrange ment of grids could. of course, be placed between insulating spacer, a ribbon-like cathode of re the anode and cathode. the cathode, secured in and spaced from the sides of said indentation, one end of the cathode ribbon (0 The upper end of the ?lament is free to slide through the opening when the ?lament changes in length due to heating, the edge-to-edge contact between the ?lament strip and mica spacer offering minimum frictional resistance to the movement of the ?lament. With the ends of the legs of the V-type ?lament anchored, its apex is free to move only in the plane of the ?lament legs and the edge-to-edge contact between the ?lament and spacer o?ers maximum resistance to the ?ow of heat from the ?lament to the spacer. In manufacture it may be found desirable to stamp out the upper insu lating spacer 5 with a transverse portion or bridge across the center of openings II to underlie that portion of the ?lament extending above the sur face of the upper insulaton, With the spacer so fractory metal, longitudinally grooved to sti?en being ?xed and the other end of the ribbon being slidably guided by said insulating spacer. 4. An electron discharge device comprising an anode and a ?lamentary cathode, an insulating spacer, the anode and cathode being insulatingly held in co-operating spaced relation said cathode comprising a ribbon of refractory metal sti?ened throughout its length with a longitudinal channel, the width of the channel in said ribbon being sub stantially less than the width of said ribbon. 50 5. A cathode for an electron discharge device comprising a straight flat ribbon, a longitudinal channel in said ribbon to stiffen the ribbon, and electron emissive material in said channel. NEWELL R. SMITH.