GB1448422A - Safety guards - Google Patents

Abstract

1448422 Machinery safety devices JOSEPH DAWSON Ltd 5 Feb 1975 [20 Feb 1974] 7644/74 Heading F2J A movable safety guard 2 for a carding machine has locking means 7, 8 adapted to lock the guard 2 in the guarding position, which locking means 7, 8 is controlled by manual means 6, 11 and is associated with an on/off switch 18 of the machine, the manual control means 6, 11 being arranged so that when operated to unlock the guard 2 it initially operates the switch 18 to switch off the machine but opening movement of the guard 2 is still prevented until the control means 6, 11 has been operated for at least a predetermined time interval after disablement of the machine to ensure that the heavy moving carding machine parts are completely at a standstill before the guard 2 is finally released by the manual control means 6, 11 for access to the machine. As shown, the locking means comprises a T-shaped latch 7, carried by the guard 2, which engages slots 17 in a latch bar 8 fixed to the machine, the latch 7 being operated by a manually rotatable handle 6 via a reduction gear-box 11 and a snail cam 15, rotation of the handle 6 initially raising the latch 7 to operate the on/off switch 18 to switch off the machine, and further rotation of the handle 6 effectively slowly raises the latch 7 to finally clear the slots 17 to release the guard 2 at which point the machine will be at rest. A second switch 19 is arranged in series with the switch 18 so as to break the circuit when depressed as the T-latch 7 is raised in slots 17 whereby if the switch 18 is faulty the machine is nevertheless disabled and slows down during the period the switch 19 is depressed, the fault being indicated when the machine re-starts after switch 19 is released by the raised latch 7. As shown, the guard 2 is pivotally supported on underswing arms (4) Fig. 1 (not shown). In the alternative embodiment of Figs. 5 to 7 (not shown) the guard (23) is supported on an overhead track (26). The locking means comprises a vertically slidable non- rotatable rod (30) which is carried by the guard (23) and telescopes within a tube (37) fast on the track (26) to lock the guard (23) in position, with the upper end of the rod (30) engaging an on/off switch (39, 40) of the machine. The locking rod (30) of the guard (23) is again controlled by a manually operated handle (34) which via a gear-box (33) and a screw device (31), on the end of the locking rod (30), slowly lowers, i.e. withdraws the rod (30) from the tube (37) to initially release the switch (39, 40) to switch off the machine, whilst the locking rod (30) is still in locking engagement with the tube (37) to prevent the guard (23) being opened until it is finally lowered clear of the tube at which stage the machine is at rest and ready for safe access thereto.