GB857223A - Improvements relating to semi-automatic presses - Google Patents

Abstract

857,223. Machinery guards. HURST, E. J. June 6, 1958 [March 18, 1957], No. 8752/57. Class 80 (4). In a power-driven screw press wherein a starting handle 15 controls a pair of driving friction discs, one of which is shown at 14, engaging a flywheel 13 on the press screw 11, a guard 33 in front of the die box 12 is suspended from arms on a shaft 23 extending across the press, the shaft 23 carrying at one end a cam 34, Fig. 2, forming an interlock with a roller 35 or a lever of the press-starting linkwork, while the other end of shaft 23 is linked to rotate a cam 40 co-operating with a spring-raised plunger 41, Fig. 1, mounted in the path of the descending flywheel 13. The guard 33, which has a window 33a, is raised by a weighted arm 28 and lowered by a handle 20. The cam 34 and roller 35 co-operate so that the press cannot be started until the guard has been lowered, and subsequently the guard cannot be raised so long as the handle 15 is held in the "on" position. The interlock 34-35 is released to allow opening of the guard during the return movement of the flywheel. The cam 40 and plunger 41 cooperate so as positively to prevent descent of the flywheel, e.g. under gravity or if the interlock 34-35 fails, when the guard. is raised to its open position. The cam 40 has a number of recesses which co-operate with the plunger 41 to prevent its complete descent at intermediate positions of the cam, i.e. when the guard is partly open.