GB1277336A - Improvements in or relating to travelling wave tubes - Google Patents

Abstract

1277336 Travelling-wave tubes SIEMENS AG 23 July 1970 [24 July 1969] 35729/70 Heading H1D A travelling-wave tube helix 10 is mounted within a metal envelope 1 by dielectric rods 3 and 31, an axially extending groove 4 in the envelope being located behind one of the rods and housing a spring 51 which applies inwardly directed pressure against the surface of the rod remote from the helix. As shown, the spring may consist of a slotted tube of oval crosssection, and two centring rods 7 may also be located in the groove. In other embodiments, the spring may consist of a corrugated strip (Figs. 1 and 2, not shown) or a U-shaped member (Fig. 4, not shown), and the spring may bear against a metal plate housed in the groove, which plate either itself bears against centring rods 7 (Figs. 2 and 6, not shown), or-dispensing with rods 7-is provided with a concave surface mating with that of the abutting rod 31 (Fig. 4, not shown). The envelope cross-section may be polygonal, with a rod at each corner, as in Fig. 3, or circular, with those dielectric rods which are not provided with a spring groove 4 having a locating groove formed in the envelope. Reference is made to the possibility of stressing the spring after insertion and assembly by the provision of a line of blind bores in the outer surface of the envelope along the groove 4, into which punches may be inserted to distort the envelope (Figs. 5 and 6, not shown).