Patent GB-152744-A (GB)
Title: Improvements in or relating to apparatus for use in making hollow articles of rubberor the like
IPC: B29C31/06
Filed: 1919-07-16
Abstract: 152,744. Roberts, F. T., and Rosenfeld, R. H. July 16, 1919. Junction rubber &c., attaching to metal and other articles.-Relates to apparatus for the manufacture of hollow rubber articles in which rubber sheets are seated by vacuum in two sets of mould cavities and are then forced together to unite the sheet at the edges, and consists of means for presenting the sheets and partly-made articles to the mould-plates together with means for removing the moulded articles. Two forms of apparatus are described, both designed for flushing-tank-valve balls. In the simpler form, Figs. 2 and 4, a plate 40 is carried by a shaft 45 which is rotatably mounted in an horizontal slide bar 50. The plate 40 can thus be drawn clear of the press and swung aside to receive a rubber sheet R and then returned to correct position (determined by stops) between the mould plates. A spring- pressed frame is then depressed by a lever 80, allowing hooks 68, 72, to engage the plate 40 and lift it so that its peripheral flange 41 presses the sheet against vacuum clamping-grooves 31 on the upper mould-plate, Fig. 4. Application of vacuum then clamps the sheet and seats it in the mould cavities, and the carrier 40 is withdrawn. The lower mould-plate 10 carrying the partiallyformed elements A in its cavities is then forced up and the sheet is severed and united to the parts A by knife-edges surrounding the cavities. The second form, Fig. 5, is adapted more especially to produce the flush-tank bulb or valve shown in Fig. 12, which has a veneer of rubber c on its stiff upper part A, which latter can thus be made of a lower grade rubber than the seating part B. The carrier here comprises a plate 190 to present the sheets to the upper and lower moulds and a connected plate 200 adapted to place the elements A in the upper mould plate 10. The combined carrier 190, 200 is vertically movable in a frame 150 which slides horizontally on alined rails 147, 167 supported respectively in vertically movable frames situated on opposite sides of the press, but capable of simultaneous vertical adjustment. In operation, the carrier is moved to the left and receives a sheet on the top and, by means of the vertically movable table 220, a second sheet on its underside, both sheets being then held by application of vacuum by the pipe 197. The plate 190 is then moved between the mould-plates and, by up and down adjustment, brings the two sheets into engagement with the upper and lower mould-plates respectively, where they are retained and seated by vacuum. The carrier is then moved further to the right into the position shown, where the plate 200 supports the elements A in register with the upper mould cavities. A succeding vertical movement brings the elements A into the moulds, when short stems carried by them puncture the upper sheet, admitting vacuum between this sheet and the elements A so as to prevent the formation of air bubbles. The carrier is now completely withdrawn, and on then closing the press the upper and lower sheets are severed, enclosing the elements A to form the complete article as shown in Fig. 12. In both forms of apparatus the carrier has means for discharging a small quantity of liquid into each filled cavity before closure of the press. To remove the formed articles, a tray, Fig. 9, is provided having apertures 241 corresponding to the moulds and a flange 242 which, when the tray is in position, closes the vacuum clamping grooves. in the mould-plates, whereupon compressed air is applied to the vacuum chambers to eject the articles into the tray.