GB1369287A - Latching device in combination with a telescopic jib for a crane - Google Patents

Abstract

1369287 Telescopic jib cranes with crabs POTAIN 12 July 1972 [12 July 1971 29 June 1972] 32462/72 Heading B8B A telescopic jib comprises a jib head 1 arranged to slide in a jib foot 2. The jib head 1 is held in the extended position shown by a finger 25 loaded by a spring 29 into a position between two stops 37, 40, Rollers 4 of a subsidiary truck 5 run on rail track 3 3 of the jib head 1. A main truck 17 is arranged to run on rollers 8 along rail track 7 on the jib foot 1 and on to a short rail section 6 on the subsidiary truck 5 where it is latched in place for movement with the subsidiary truck 5 along the jib head 1. In the latched position shown a stop 52 on the main truck 17 is trapped between rockers 19, 21 pivoted on the subsidiary truck 5. The main truck 17 is attached in a conventional manner to an endless cable (10), Fig. 8 (not shown), for movement along the jib. When it is desired to transfer the main truck 17 to the jib foot 2 movement of the latched trucks 5, 17 to the left introduces the leading end of the rocker 19 between stops 23, 24 on the jib foot 2 pivoting the rocker 19 clockwise and releasing the stop 52 automatically to permit the required transfer. At the same time the auxiliary truck 5 is retained in position by the rocker 21 pivoting clockwise to retain the rocker 19 in position between the two stops 23, 24, Fig: 4 (not shown). Conversely, when the main truck 17 is run off the track 7 on the jib foot 2 on to the rail section 6 on the subsidiary truck 5, the stop 52 pivots the rocker 21 out of the way of the rocker 19 allowing the rocker 19 to pivot to the position shown.