Patent GB-191014302-A (GB)
Title: Improvements in and relating to Fluid-operated Hammers.
Inventor: ARNOTT ROBERT FLEMING
IPC: B21J7/24
Filed: 1910-06-13
Granted: 1911-03-30
Abstract: 14,302. Arnott, R. F. June 13. Fluid-pressure hammers.-A fluid-pressure hammer is provided with the following improvements, (1) a rotary valve having a step-by-step movement, a part of the operating- mechanism being carried by the ram head, (2) mechanism separately operated or controlled by movement of the ram head for raising or lowering the hammer as a whole and for preventing accidental lowering of the hammer in combination with a device by which the speed of lowering of the hammer is frictionally controlled, (3) means for controlling the flow of working-fluid at starting, whereby premature operation of the ram head is prevented until the pile &c. is in position, (4) mounting the mechanism in the heavy and stationary frame members. The ram head f, Fig. 7, is connected to a piston-rod e, of which the piston d moves in a cylinder c formed in a heavy case a, which may be formed separately from or integrally with the side-members b. Pressure - fluid is supplied to the cylinder through a throttle valve i, passage i<1>, valve-chest j, rotary distributing-valve k, Fig. 6, and ports n, o, and the exhaust escapes by a port p. The valve k is operated from the ram head f by means of a rod g, Figs. 1 and 7, the upper end of which is constructed in two parts with a gap u between, in which are mounted valve-trips v, w as shown in Fig. 9. On the downward stroke, the nose 2 of the trip-plate 3 strikes the toe 4 of the trip-arm v of the valve lever and turns the valve k from the position shown in Fig. 14 to that shown in Fig. 15. As the ram head f continues its downward travel, the nose 6 strikes the toe 4 and turns the valve into the position, Fig. 16, whereby the expansion continues to take place at the upper end of the cylinder, while compression occurs at the lower end. The nose 8 then contacts with the heel 10 of the triparm and turns the valve into the position, Fig. 17, connecting the lower end of the cylinder to the admission port i, and the upper to the exhaust p. On the upward movement, the position shown in Fig. 15 may be avoided by employing two toes 11, 14 on the trip w which contacts with the trip-arm s. The arm t acts as a stop. The hammer is thus cushioned at both ends of its stroke. The hammer is raised or lowered as a whole by means of a rod 20, Fig. 7, attached at its upper end with a rack gearing with a pinion 21, Figs. 1 and 20, which operates a worm 32, worm-wheel 34 and chainwheel 36, Fig. 6, meshing with an endless chain 37. The pinion 21 is made in two parts 22, 23, Fig. 20, with a diaphragm 25 between, the parts 22, 23 being constructed as hall free - wheel clutches in opposed directions. By sliding a shaft 28 and collar 31 into the mid position with the collar 31 inside the diaphragm 25, the wheel 21 can be made free in both directions, whereas by sliding the collar 31 into one or other of the parts 22, 23 the wheel 21 is made free in one or the other direction. The part of the chain 37 above the hammer may thus either be lengthened or shortened and the hammer lowered or raised. A rotary engine may be employed to operate the worm 32 in place of the pinion 21. The hammer may also be lowered by slackening a band-brake 42, Fig. 7, which passes over a drum 41 mounted on the same shaft 40 as the chain-wheel 39, Fig. 1. Each of the frame members b is provided at its lower end with a buffer-plate 56, Fig. 7, and jaw-plates 57 of varying size upon which rests a pile-plate 59 from which projects a pile-pin 60. These prevent lateral movement of the hammer. In a modification, Fig. 26, the lower port o<1> does not enter quite at the bottom of the cylinder, and the cylinder is grooved as shown at 62 so that any steam which may leak past is prevented from raising the cylinder. Thus the ram cannot be actuated until the pile is in position and the hammer is resting upon the top thereof, the effect of which is to raise the ram and uncover the port o<1> and so admit the pressure fluid.