GB963034A - Improvements relating to knitting pins - Google Patents

Abstract

963,034. Extrusion machines. NEEDLE INDUSTRIES Ltd. Oct. 1, 1962 [July 1, 1961], No. 23838/61. Heading B5A. [Also in Division D1] In the manufacture of knitting pins comprising a metal core embedded in thermoplastic synthetic resin a series of rod-like metal cones 12, Fig. 3, are supplied from a feed roller device 18, Fig. 2, to an extruder head 21, from which the cores coated with synthetic resin are passed through a cooling water tank 9 to a haulage device 19. The feeding device 18 delivers the cores 12 in succession with gaps between adjacent ends of the cores so that synthetic resin is delivered at an increased rate between the cores to produce enlargements 72, Fig. 4. At the same time the speed of the haulage device 19 is increased to produce necked portions 73 at the warmer parts of the extrudate. The partly formed pins are separated by severing at the portions 73 and the pointed ends are shaped in a heated die cavity, whilst the parts 72 are upset to form knobs at the ends of the pins. The die 20 is carried in a holder 8 secured to the die head by three angularly spaced screws 7 so as to be radially adjustable. The guide tube 24 for the rods 12 is axially adjustable, and an electric heating element 4 surrounds the die holder 8. Alternatively, the pins may be made individually by injection moulding in a cavity 98, Fig. 17, in which the core 12 is supported by spacer elements 99 preferably of the same kind of synthetic resin as that injected into the cavity through the passages 100.