GB1020077A - Hydraulic hammer - Google Patents

Abstract

1,020,077. Pile driving. RAYMOND INTERNATIONAL Inc. Dec. 2, 1963 [Dec. 10, 1962], No. 47557/63. Heading E1H. [Also in Division B3] A pile driving hammer comprises a cylinder 12, piston 13, connecting rod 14 secured to ram 11, a cam 32, 33 linked to said ram, a rotory cam follower 28 oscillated by said cam and a slide valve 18 having an arm 18a linked to cam follower 28 for reciprocation thereby between a pair of valve actuating positions. Hydraulic fluid passes from pumps 41, 42 through valves 50, 51 into pressure line 55 connected to pipeline 15 which passes the fluid into distribution box 16. From box 16, pipe 17 leads to cylinder 12 below piston 13, pipe 21 leads to an inlet accumulator 22 precharged with gas to a pressure two-fifths that of the hydraulic fluid supplied over pipeline 15, and pipe 20 leads to slide valve 18. From valve 18 pipe 23 extends to the top of cylinder 12 and drain pipe 25 extends to an outlet accumulator 27 precharged with gas to 100 p.s.i. When the piston 13 rises, the cam follower 28 is rotated clockwise and through linkage 29, 29a, 30 and 18b pushes arm 18a to the left which allows pressure pipe 20 and pipe 23 to communicate and pressure fluid to enter the top cavity of the cylinder. This forces the piston 13 down which rotates the cam follower anticlockwise and moves arm 18a to the right which allows pipe 23 to communicate with drain pipe 25 and thus the pressure on top of the piston is removed and the piston rises again under fluid pressure from pipe 17. When the piston rises and the valve 18 is actuated to reverse the piston, this reversing effect does hot act immediately since the piston accumulates a considerable velocity in its upward travel, and therefore while it continues to rise will discharge liquid from the upper cylinder cavity through pipe 23 into box 16 where most of it will go through pipe 21 into accumulator 22. The accumulator 22 is 5 to 20 times the cylinder volume. The valve 18 is designed with an overlap between its two actuating positions. The cylinder 12 is suspended by a universal coupling from plate 60 and piston rod 14 is connected to ram 11 by means of knob 83 and rings 93 and 94 (Fig. 3, not shown).