GB516229A - Improvements in releasing devices for power operated drop hammers - Google Patents

Abstract

516,229. Power hammers. BURGESS, A. F. (Menck & Hambrock Ges.). June 15, 1938, No. 17792. [Class 83 (iv)] In compression ignition pile drivers with a stationary cylinder in which descent is accelerated by compressed air above the ram for starting, the cylinder and ram are both lifted and allowed to fall until the cylinder engages the pile whereupon the ram is released to continue its movement. A spring-pressed pivoted hook 10, Fig. 1, carried by a lifting rod 2 is splined for a key 15, which prevents rotation of. the rod. The hook has a toothed part 10a engaging a second hook 3 fixed to a pivot 7, to which is also attached a spring pressed lever 8, having an attached rope 14. When starting, a lifting rope 16 is attached to the rod 2 and the rope 14 pulled downwardly to rotate the hook 3 and free the .hook -10. A ram 13, which is at its .lower position is engaged by lowering the rod 2 until the hook 10 engages a recess in the ram, whereupon the ram is raised by the rope 16 and rod 2. When the ram reaches its upper position, the hooks 3, 10 are engaged and the cylinder and ram lifted. When the rope 16 is slackened the rod 2 drops slightly as shown, and the hook 10 has rotated, the hook 10 is released from the ram. In a modification a spring pressed latch enters a recess in a sleeve carrying the hook for engaging the ram to maintain the ram in position. In another form the ram is engaged by levers 10c, Fig. 6 in a cage having projections 28 that are supported by releasing levers 26. A wedge-end 21 is connected by a chain 37 to a drum 25 on a shaft 41 having pinions at its ends engaged by racks 43 on a frame carrying a loose pulley for a lifting rope. The lifting rope may, however, be attached directly to the chain 37. On lifting, the chain is tightened and spreads the levers 10c against the tapered shoulder 32 in the ram by the action of the inclined surfaces 29 on the wedge end.