GB798862A - Improvements in or relating to injection molding process and apparatus for carrying out said method - Google Patents

Abstract

798,862. Injection-moulding tubular articles. PARKER PEN CO. Sept. 19, 1955, No. 26769/55. Class 87(2). A tubular article, e.g., a ball-point pen ink container is made by injecting plastic material into the annular space between a mould 2, Fig. 4, and a core 12. The material is injected downwardly through holes 21, 25 in a member 18, and pushes downwardly before it a slevee 31 which surrounds the core and keeps it centrally located. The sleeve is split over most of its length, to provide resilient tongues which grip the core, for a reason given below. The sleeve comes to rest at the bottom of the mould, its lower (split) end being accommodated within a recess 28 in a bushing 27 secured in a plate 26. Each core is fixed at its lower end to a plate 13. There are twenty-four moulds 2, and they are accommodated in a block 3. Fig. 2 shows the whole apparatus closed. When the apparatus begins to open, first an upper plate 29 carrying a sprue member 47 separates from the 3-26-13 assembly and a sprue puller 52 pulls the sprue 55 out of gate 48. Undercuts 57 in plate 29 initially retain sprue arms 53, and sprue projections 56 are broken away from the moulded articles. On further movement of plate 29, sprue projections 58 are pulled out of the undercuts, as in Fig. 3. Plate 29 opens to a degree determined by headed bolts 36. Then the 26-13 assembly separates from block 3, to a degree determined by bolts 42, the cores and moulded articles 30 being thereby pulled out of the moulds. Then plate 13 separates from plate 26, whereby the cores are pulled through the sleeves and out of the articles, as shown in Fig. 3, and the articles may be removed. When the sprue has been removed the apparatus may be closed again, and as it closes, each sleeve 31 is pushed back to the top of its mould by a step 46 on its core, the resilient tongues 33 having closed in to lie on this step.