GB1027341A - Improvements in or relating to moulding apparatus - Google Patents

Abstract

1,027,341. Moulding keys for typewriters &c. S. KOBAYASHI. March 25, 1963 [April 27, 1962], No. 11746/63. Heading B5A. A metallic mould for moulding plastics materials, especially for shaping two-tone typewriter keys or telephone dials, comprises an upper mould 1 (Fig. 3, not shown) and two lower moulds 2, for a first stage and 3 (Fig. 4, not shown) for a second stage, the upper mould 1 being provided with several vertically movable plungers 14 and the first lower mould 2 being provided on its upper surface with small projections 4 serving to provide gates c for the second step, the two lower moulds being interchangeably engageable with said upper mould so as to enable the first step of the process to be carried out by injection moulding into the upper mould and the first lower mould 2, whereafter the product remains in the upper mould and the second step then being carried out by injection moulding into the upper mould and the second lower mould 3. The first lower mould 2 is fitted to the upper mould 1 and the plungers 14 are moved down into contact with the projections 4 by cylinders 20 acting on rods 16 through a plate 18. The first injection moulding is carried out through gate 5. The first lower mould 2 is then removed, leaving the first moulding attached to the upper mould 1, and the second lower mould 3 is fixed in its place. This mould 3 has a cavity 6 which is below the first moulding. The plungers 14 are now raised until in contact with an intermediate plate 11 in the upper mould 1. The second injection is now made through gate 7, giving a two-coloured article having smooth upper and lower surfaces.