GB436424A - Production of hollow rubber articles - Google Patents

Abstract

436,424. Balls. FABER, P., 115, Hauptstrasse, Idar-Oberstein, Germany. Jan. 14, 1935, No. 1279. Convention date, Jan. 12, 1934. [Class 132 (ii)] [See also Group V] Hollow rubber balls are produced from aqueous dispersions of rubber by depositing the undissolved constituents of the dispersions on the inner walls of hollow porous moulds which are not completely filled with the dispersions, the moulds being given simultaneous rotational movements about two axes preferably disposed at right angles. By using several coloured dispersions, variegated articles may be produced. The mould may be provided with a pressure-equalizing tube projecting so far into the interior of the mould that the end is always above the surface of the dispersion. The tube may be of glass, but if a rubber tube is used it may be left in the article formed and used to inflate it. The mould may have an opening accommodating a plug carrying the tube, a flange on the tube resting on the inner end of the plug, while the tube is extended by a paper sleeve. In making a ball, a piece of coagulated rubber may be introduced with the dispersion, through which piece a hollow inflating needle may later be forced. Fig. 5 shows a portion of a mould for making a ball, and Fig. 3 shows the corresponding finished ball. The mould takes a porous plug 14 having a passage 13 taking a rubber tube 17 which fits tightly. In the finished ball the rubber tube is firmly united to the deposited material forming the recess 7, and a sealing disc 8 is accommodated in an annular rebate 11 formed by a shoulder 16 in the mould. The rubber tube is shown extended through a slit in the sealing disc, but after inflation it is folded under the sealing disc. During or after deposition of the rubber, the mould is warmed, and then the solidified ball is taken out, dried and vulcanized.