| 摘要 |
565,578. Electron discharge apparatus. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Feb. 4, 1943, No. 1841. Convention date, Jan. 1, 1942. [Class 39 (i)] [Also in Group XXII] Stamping processes.- A cathode sleeve for electron discharge devices comprises a wrapped, butt jointed and swaged metal tube of any transverse section and having uniform wall thickness, the external face being emissive when hot. The sleeve may be corrugated, Fig. 8, or have washers threaded thereon, it may have two different diameters 4, 9, Fig. 6, or have a part 4a outside the spacers 5 with a diameter less than that of the main portion 4 or of a collar 12, Fig. 5, so that an emissive coating thereon is not damaged when passing through the spacer 5. The sleeves may also be formed with a flange 7 or with tapered ends 8, Fig. 8, which are a push fit in the spacer holes. The cathode sleeves are made by drawing a nickel strip S, Fig. 9, through a skelping die 20 to form an openjoint tube S<1> which is fed step-by-step through dies A, B, one of each pair being rapidly reciprocated so as to reduce and give the desired form 4 to the tube, which is oscillated about its axis during the process, e.g. by rocking the skelping die. This hammering hardens the outer surface of the tube and sets up a strain therein, pressing the butted edges together. The shaped lengths of tube may be broken off or severed by a knife 23. The edges of the strip may be coated with silver or other hard solder and the tube be heated before or after hammering to effect a union. The surfaces 4a, 9 may be coated with electronemissive compound, such as barium-strontium oxides and an insulated heating coil is inserted at the lower end of the sleeve. Specification 15858/13, [Class 83 (iv)], is referred to. |
