GB322908A - Improvements in grabs - Google Patents

Abstract

32,2,908. Page, M. W. Flood-, and Westwood & Co., Ltd., J. Dec. 21, 1928. Grab - buckets. - Relates to grabs of the kind in which the buckets are released by turning a horizontal pin 19 which normally locks a vertical pin 18 on the lower cross-head 2 to a collar 17 on the lower sheave-block 15. Instead of releasing the pin 19 by means of a suspended ring, or by means of a weighted lever which operates only on lowering the buckets to the ground, the releasing means is made operable manually at any time and operates also automatically when the grab rests upon the ground. As shown, the lower cross-head 2 and sheaveblock 15 are guided by the telescopic rods 4, 3. A weighted lever 22 on the pin 19 tends to move the pin to the releasing position, Fig. 6, but a weighted trigger 26 pivoted freely on the pin normally takes up a vertical position so that a pin 25 thereon engages a lug 24 on the lever 22 and holds the pin 19 in the locking position. If the open buckets rest upon the ground and the block 15 is lowered from the position shown, the trigger 26 moves away from the stop 27 on the upper block 14 and stands vertically against a stop 29, so that when the collar 17 passes over the pin 18 the locking pin 19 snaps into the recess 20. When the block 15 is raised to close the grab, the trigger 26 bears against the stop 27 as shown, but the pin 19 is held frictionally in the locking position with the lever 22 horizontal. The pin is released either by lowering the closed grab on to the ground so as to leave the hoisting rope slack with the pin free to turn under the weight of the lever 22, or by pulling on the hand-line 28 so that the pin 25 on the trigger strikes a blow on the end 23 of the lever 22 to dislodge the pin whilst the grab is suspended. The lever 22 may be spring-actuated.