GB353210A - Improvements in guards or protectors for preventing injury by presses and like machines - Google Patents

Abstract

353,210. Controlling machinery guards. SCHULTE, O., Niederschlema, Saxony, Germany. June 26, 1930, No. 19462. Convention date, May 3. Addition to 353,207. [Class 80 (iv).] In pneumatically-actuated guards for presses &c., the valve arrangement described in the parent Specification for controlling the supply of compressed air or other medium through pipe n to the pneumatic device o, q for operating the starting- lever p is modified by providing inlet and exhaust ball valves 3, 4 opened alternately by a spring- returned rocking lever 1, which is depressed by a nose 5 on the guard lever c when fully raised into the safety position by the pneumatic piston e, as shown in Fig. 3. If the spring 2 should break, the lever 1 is positively actuated on descent of the guard lever by a further nose 7 thereon. The cylinder o for the lever p is movable, the return spring therefor being supplemented or replaced by compressed air led directly from the main supply pipe h through a pipe n<1> to the upper side of the fixed differential piston q. The guard lever c is latched in its safety position by a pawl 8, which is tripped towards the end of the downstroke of the press ram by the rod r which opens the exhaust ball valve s for the guard-actuating cylinder f. To ensure that the lever p is released soon enough to avoid " repeats " in high-speed presses, the valve s may be respectively opened and closed early in the down and up strokes by positively limiting the motion of the rod r in a guide x, Fig. 1, and connecting it to the arm on the press ram by friction washers 9 allowing slip.