GB697255A - Improvements in and relating to injection moulding and articles produced thereby - Google Patents

Abstract

697,255. Injection-moulding hollow articles. WAGNER, E. V. April 18, 1952 [April 25, 1951], No. 9606/51. Class 87 (ii) A hollow article having. a head or closed end, e.g. a tubular reservoir a for a ball-pointed writing instrument or a pen or pencil cap or point protector, is made by a two-stage process. In the first stage the article is injection-moulded in the apparatus shown in Fig. 2, which includes a mould 7 and core 3, the free end of the core or the sleeve 11 by which it is supported having grooves or the like 3a through which plastic material passes into the moulding space between the mould 7 and the core. This results in the production of an article having gaps in its head or closed end corresponding to the places at which the core is supported by the sleeve. In the second stage the plate 10 in which the sleeve 11 is disposed is removed (the incompletely-moulded article being left in the mould) and in its place is put another plate 10a having a sleeve 12, Fig. 3, which is spaced from the end of the core, more plastic material being then injected through sleeve 12 to fill or cover the gaps in the head or closed end of the article and produce a smooth end b. (This end is afterwards drilled to receive a ballhousing.) The plate 10a and stripper plate 8 are then raised, the plate 8 retaining the article which is thus withdrawn from the core pin. Figs. 2 and 3 show apparatus for moulding many reservoirs simultaneously, each core being held in a plate 2 and passing through a bush 5 in a bolster 4. The moulds 7 are carried in a plate 6 and project into the stripper plate 8. Guide pillars 9 are provided.