GB1393225A - Cranes - Google Patents

Abstract

1393225 Mobile luffing arm apparatus INTERNATIONAL HARVESTER CO 17 Sept 1973 [21 Sept 1972] 43600/73 Heading B8H A jib 8 is pivotally mounted on a support frame 10 for movement about a horizontal axis 9 under the action of a ram 13 and a load-engaging hook 18 is mounted on the jib 8 for movement therealong in response to pivotal movement of the jib in order to maintain the horizontal distance between the hook 18 and axis 9 constant. The hook 18 moves along rails 15 (only one shown), under the action of an hydraulic ram 22 to which fluid is supplied via an hydraulic control valve 41 so that on raising the jib 8 by means of the ram 13 a bell crank 32 on the jib is rotated therewith and actuates the valve 41 through a rod 38, the valve then supplying fluid to the ram 22 to cause its extension and thus movement of the hook 18 outwardly from the frame 10, such movement effecting angular movement of a telescopic arm 25 which is connected at one end to the hook 18 and at its other end to the bell crank 32 through a rod 30, the arm 25, in moving from its full line to its phantom line position shown, causing the bell crank 32 to rotate in the direction opposite to the direction of its rotation caused by the pivoting of the jib 8, thus returning the valve 41 to its neutral position. On lowering the jib 8 the hook 18 is moved inwardly towards the frame 10, the latter being mounted on a vehicle (5), Fig. 1 (not shown).