As a expr amp; # 252; ckkolben f amp; # 252; r plastic mass of which a closure made of elastic material f amp; # 252; r is a hollow cylindrical strand press guide amp; # 228; lter

摘要

1302981 Pistons ALFRED FISCHBACH KG KUNSTASTOFF-SPRITZGUSSWERK 27 April 1971 [9 July 1970] 11664/71 Heading F2T [Also in Division Fl] A closure of resilient material operable as a piston to expel plastic material from a container 9 comprises an externally convex end plate 2 having a sealing lip 3 around its edge, a skirt 1 extending from the lip 3, stop means, e.g. an annular ridge 4, on the inner surface of the plate 2, an annular lip 6 within the skirt and extending from the plate axially beyond the stop means 4 and a thickened wall portion 8 on the skirt which is spaced from the sealing lip 3 and, in use, engages the container wall. The closure is inserted to the filled container by a piston 10, Fig. 2, formed to engage firstly the edge 5 of ridge 4 and then the edge 7 of lip 6 whereby the lip 3 is not in contact with the container wall and any air is free during ininsertion to escape past the skirt. The discharge end of the container has an outlet 12 closed by stopper 13 (Fig. 3). To expel plastic material, after removing the stopper and fitting a discharge nozzle 14, the closure is pressed inwards by a plate 15 which engages firstly the edge 7 and then the edge 5 so that the lip 3 sealingly engages the container wall and the closure acts as a discharge piston.