GB1051585A - - Google Patents

Abstract

1,051,585. Moulding discs of thermoplastic material. ELECTRIC & MUSICAL INDUS TRIES Ltd. Aug. 30, 1963 [Aug. 30, 1962], No. 33286/62. Heading B5A. A device for moulding discs from synthetic thermoplastic material, comprises a lower plate 2 and a rotatable upper plate 1 in close facing relationship, said upper plate being rotatable in discreet steps to bring at least one aperture therein to a plurality of stations, means for introducing thermoplastic material in granular form into the aperture at a first station 4 in which position the lower plate closes the bottom of the aperture, means for passing heated gas or vapour into said aperture through the lower plate at a second position 5 to cause the granules of said thermoplastic material to soften and adhere together to form a biscuit of said material, and an aperture in the lower plate at a third position 6 through which the biscuit may fall under gravity on to a record press. The upper plate 1 is rotated by a lever and ratchet assembly 9, 10. At the heating station 5 gas or vapour is blown upwardly through a duct 14 (Fig. 1b, not shown) over a heating element 20, thence over the material in the aperture and finally is exhausted through a duct 8. During the heating step the granules of thermoplastic material are retained in the aperture by means of two gratings 12, 13 located above and below plate 1. The gratings comprise four radial ribs 31 (Fig. 2a) supporting five circular ribs 32. Additional arcuate ribs 36 are provided on top of ribs 32 forming arcuate grooves 33 concentric with the axis of rotation of plate 1. These ribs provide a suitable passage for the heated gas.