1,218,335. Latches. P. J. PINGON. 20 June, 1969 [30 Aug., 1968; 24 Dec., 1968], No. 31414/69. Heading E2A. [Also in Division B8] A tower crane comprises a chassis 1, a superstructure 5 with a counterweight 7 on a slueing device 6 and a mast with two elements 9, 10 hinged together at 11. The lower element 9 is hinged to the superstructure at 8 so that the mast can be folded into a horizontal position with the elements 9, 10 superimposed as shown in Fig. 1 in full lines. A carriage 14 is arranged to move along the element 9 by rotation of a lead screw 15, rods 18 being pivoted on trunnions 17 on the carriage 14 and on a pedestal 12 on the superstructure 5. The element 9 is erected to its vertical, operative position 9' by movement of the carriage 14, the rods 18 paking up a position 18'. At the same time a set of toggle lines 20, 22, 23 pivoted on the trunnions 17, to each other at 21 and respectively to the elements 9, 10 at 24, 25 causes the element 10 to assume its vertical, operative position 10'. The element 10 may be telescopic and extended further when vertical. Fig. 2 shows hows a jib 27 may automatically be moved into its operative position through tie bars 33, 34, beams 30 and hinged rod 37 connected to hinge 11 as the mast is raised. Fig. 6 shows a telescopic jib 27, 40 controlled by an endless cable 53, from a winch 54, which passes over a pair of pulleys 55 and around a horizontal pulley 56 at the end of the first jib length 27. The cable 53 is attached at 57 to the second jib length 40. A further endless cable 58 is engaged around the jib length 40 on four pulleys 59 and secured at 60 to a crane trolley 45, and at 61 to the end of the jib length 27. As telescoping occurs the trolley 45 thus moves over the jib length 40. Figs. 7, 9 show a modification wherein a telescopic jib with a second, movable length 64 longer than the first length 63 has a trolley track 72 forming an extension of a trolley. track 69 when the jib is fully telescoped (as shown in outline). The trolley 71 is moved over the track 69 by a cable (79), Fig. 8 (not shown) when the jib is fully telescoped and may run on to the track 72 where it is automatically latched to the length 64 by a hook 95 engaging a dog 101, a hook 87 being disengaged from a dog 92 by an abutment 93 engaging a lever 90 pulling a rod 89 to release length 64 from length 63. The hooks 87, 95 are respectively urged to their engaged positions by springs 91, 98.
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