GB812466A - Machine guard - Google Patents

Abstract

812,466. Machinery guards. JAGUAR CARS Ltd. Nov. 9, 1956, No. 34266/56. Class 80(4). In a machine in which the drive of the operating tool is controlled by a fluid-actuated member (e.g. the engagement of a clutch or release of a brake) a movable guard controls the supply of the actuating fluid so that the drive can only be effected when the guard is closed. In Fig. 1 two sliding guard parts 11, 12 carry flexible pipe portions 15, 16 which are connected respectively to a compressed-air source and to the fluid-actuated member controlling the drive. The ends of these pipes 15, 16 are provided with coacting coupling parts 17, 18, the part 17 having a valve with a projecting stem 19 and the part 18 having a socket 20 for receiving the valve stem 19. The valve stem 19 is spring- loaded at 42 (see Fig. 5) to project when the guard parts are open as in Fig. 1 to close axial and transverse passages 43, 70 therein. When the guard parts are brought together the stem 19 of coupling part 17 engages in the socket 20 of coupling part 18 and is pressed inwardly to open the passages 43, 70 to the inlet pipe 15 which can then pass the compressed air to pipe 16 and the fluid-actuated member for starting the drive. The pressure in pipe 16 is also utilized to operate a locking bolt which must be released before the guard can be opened. The release of such pressure-operated lock may be effected automatically at the end of each operational cycle of the machine as by a cam actuating a pressure release valve. A single sliding guard may be used instead of the two-part guard and may be of part-cylindrical form to move in a curved path.