GB433799A - Improvements in or relating to guards or safety devices for machines - Google Patents

Abstract

433,799. Machinery guards and safety devices. BROUGHTON, G. J., Security Works, Vere Street, Birmingham. Feb. 26, 1934, No. 6155. [Class 80 (iv)] A guard for machines particularly presses, stamps and the like, comprises a guard member movable by hand to an operative position and associated with a member or stop adapted to be moved between the engageable members of the machine clutch, the arrangement being that said stop or member positively prevents said clutch members being moved into engagement until the guard member is moved to the operative or safety position, such movement of said guard member withdrawing said stop or member from the position between the clutch members. Further, a safety stop is provided to prevent inadvertent operation of the machine whilst the guard is in the raised or inoperative position. The invention is described as applied to a power press in which the die is actuated by a crank on a shaft 10 adapted to be rotated through a clutch. The danger zone is adapted to be enclosed by a guard consisting of two end frames 13 connected by a front frame 14, the frames being covered by a grid of wire mesh. This guard is mounted on a transverse shaft 15, and each end frame has an extension 16 clamped adjustably between an arm 17 on the shaft and a plate 18 bolted thereto. The guard is balanced by weights 38. The arm 17 has a boss to which is secured an arm 21 connected by link 23 to a sliding rod 26 which in turn is connected by linkage 29, 30 to a shaft 31 on which is mounted the stop arm 33 held by a spring normally in the path of the movable clutch member. The clutch cannot be operated until the guard 13, 14 has been lowered by hand into the protective position, and further the guard cannot be raised while the clutch members are engaged, the stop arm 33 being prevented by the clutch from moving. To prevent operation of the machine whilst the guard is raised and due to inadvertent or accidental over-running, a plunger 39 is connected by a link 41 to a crank-pin 42 on the main shaft 10. While the guard is raised, the rod 26 acts as a stop to plunger 39, but when lowered, the rod 26 is moved so that a slot 44 comes opposite the plunger and permits it to reciprocate.