Patent GB-572261-A (GB)
Title: Improvements in or relating to the manufacture of articles made of metal and rubber bonded together
IPC: B29C45/46
Filed: 1942-10-12
Abstract: 572,261. Moulding rubber. METALASTIK, Ltd., WOODCOCK, W.J., and GOODMAN, L. T. Oct. 12, 1942, Nos. 14264/42 and 4625/43. [Class 87 (ii)] Rubber is forced under pressure into moulds through a charging connection which may be opened and closed, and rubber escaping through a relief orifice or valve gives an indication of changes in rubber charging conditions, e.g. when a mould is full, the flow of rubber through an orifice increases. The relief orifice or valve is disposed between the pressure-applying means and the mould. The invention is described in connection with the charging of rubber into moulds which are constituted in part by U-shaped metal mountings 60, 61, Fig. 5, and 78, 79, Fig. 7, which are to be bonded together by rubber. In the apparatus shown in Figs. 1, 4 and 5, the mountings 60, 61, assembled in pairs in jigs which include mould parts 63, 64, are located by dowel pins on an intermittently-rotating table 17. (Figs. 1 and 4 are elevations, and Fig. 5 a plan view.) On top of each pair of mountings rests a plate 38 having holes 40 through which rubber is to be charged into the moulds. From rest, the table revolves and a plate 38 is brought beneath a die box 15 which is fed continuously with rubber by a screw extruder head 10. The table then stops and a clamping plate 46 is rotated (on a quick thread 45a on an axial boss 45) to descend and hold the plate and mountings securely on the table. With the plate 46 also rotates a rubber-supplycut-off plate 44 carrying short tubes 47, which are thus brought into register with the holes 40 and with channels 43 leading from die box 15, as shown in Fig. 4. (Alternatively, opening and closing of the charging connection may be caused automatically by rise and fall of pressure in the rubber supply.) Rubber then passes into the mould, and when the latter has been filled (at which time the rubber supply pressure may be reduced), rubber escapes through an orifice 51 which may be spring-loaded to open only under excessive pressure or, as shown, permanently open. When the mould is full, the cut-off plate 44 is turned from the position shown in Fig. 4 to isolate the mould from the die box, and simultaneously a plate 52 is moved to uncover a relief port 15a through which rubber escapes. The table then moves one step forward, and the jigs with the mountings and rubber filling are removed. The rubber is then vulcanized to the mountings, e.g. as described in Specification 572,275. The extruder 10 is driven by electric motor 12 through shaft 13 and gearing 14. The table 17 also is driven by the motor through clutch 19 and telescopic shaft 22. A shaft 25 can be turned manually or by means of an air motor 30 and lever 31, and when it is turned three things happen : (1) The clutch 19 is pulled out, via link 27 and lever 28, and the table stops rotating. (2) A link 33 rocks the cut-off plate 44, thus clamping the mould to the table and allowing acess of rubber from the die-box 15 into the mould. (3) The same link 33 rocks plate 52 to cover port 15a. Fig. 7 (which is a plan view) shows a modification in which the rotating table 17 is not used. The manuallyoperated cut-off plate 74 has 'orifices 80 which can be aligned with orifices 81 in the die box, and has also seatings for the mountings 78, 79. In use, the orifices 80, 81 being out of alignment, the mountings are placed in the seatings. Then a jig 85 having a handle 84 is placed against the outer ends of the mountings, a cap 83 on the jig fitting over pins 82 which project from the plate 74. Finally, the plate 74 is turned to the charging position shown, the jig and mountings turning with it; in this position a bar 86 abuts an annular plate 89, the jig being thus held in position against the pressure of the issuing rubber. When the orifices 80, 81 are in alignment, as shown, the relief orifice 90 is closed, but when the mould is full it opens automatically.