GB1440751A - Carriage primarily for use in a timber extraction system - Google Patents

Abstract

1440751 Single-cable hoisting and transporting J FLEMING 20 June 1973 [22 March 1972] 13283/72 Heading B8B [Also in Division B7] A carnage 10, particularly for use in a timber extraction system, is shown slung from a burden cable 11 which has an adjustable skid 11a. A haul rope 12 is used to move the carriage 10 to a loading station, and it is moved to an unloading station at the skid position by a haul and hoist rope 13. The rope 13 at its free end has a load hook (not shown), adjacent which is an abutment member 27a. As shown in Fig. 2 a sleeve 17 slidable in vertical guides (not shown) on the carriage 10 and mounting a pulley 26a is biased into its upper position by a spring 18 acting through bell-crank lever 19 and link 20. At the loading station, when a load is applied to the rope 13 the sleeve 17 is moved downwards, against the action of the spring 18, until a bar 42 on the sleeve 17 engages a stop 43 on the carriage 10. The load can now be raised, the abutment member 27a passing through guide rollers 44 into the sleeve 17 where it lifts the free end of a lever 39 pivoted to lugs 40 against a spring 41. This action lifts a bolt 36 clear of a recess 37 in a latch bar 28 which is moved through a bell-crank lever 31 and a link 30a under the action of a spring 25a through a slot 29 into a position below the member 27a, locking the member 27a to the sleeve 17 and thus to the carriage 10. At the same time telescopic rods 22, pivoted to each other at 23 and at their other ends to the carriage 10, are forced into their upper position, Fig. 3 (not shown). The carriage 10 with its load can now be moved by the rope 13 until the skid 11a is engaged by skids 24 on the rods 22 forcing them down and thus withdrawing latch bar 28. This releases the member 27a so that the load can be lowered, the bolt 36 entering the recess 37 to retain the latch bar 28 retracted. Should an empty hook be raised the sleeve 17 is not depressed by the tension in the rope 13 and bar 42 remains in line with the latch bar 28 preventing it from locking the member 27a to the sleeve 17 and thus to the carrage 10. In a further embodiment, Fig. 4 (not shown), the telescopic rods 22 are replaced by strikers (65) at either end of the carriage 10, the skid 11a being replaced by adjustable stops. In this case the latch bar 28 is withdrawn to release an abutment member (59a) from the sleeve 17 when a striker contacts a stop.