GB512172A - Improvements in fluid pressure hammers - Google Patents

Abstract

512,172. Power hammers. NAZEL, B.S. :May 3, 1938, No. 13188. [Class 83 (iv)] In a pump piston power hammer the ram may be held up for manipulating the work and may be operated to strike single blows or a succession. The hammer comprises a power cylinder 2, with piston 4 driven by electric motor, ram cylinder 2 with hollow ram 3 having a cushioning chamber 25, cylindrical valves 11, 12 operated by linkage from a handle 19, spring pressed check valves 13, 14. and spring pressed suction valves 15, 16. The casing of the valve 11 has a series of ports one communicating with a chamber 24 of the power cylinder above the piston, a second with a chamber 22 above the ram, a third port leading to an atmospheric chamber 36, a fourth communicating with a chamber 33 and finally one communicating with a reservoir or pressure chamber 35. Similarly ports in the casing of the valve 12 lead respectively to a chamber 23 below the piston 4, a chamber 21 below the head of the ram 3, atmosphere through the hollow pedestal 1, a chamber 34, an auxiliary reservoir 47, and the reservoir 35. Air may be drawn from the chamber 36 into the chambers 33 and 34 through the suction valves and therefrom respectively through the check valves into reservoirs 35, 47. A bye pass connecting the upper and lower parts of the cylinder 2' through the cylinder wall, is controlled by a rotary valve operated by a starting lever 20 which is shown in Fig. 1 in the starting position with the byepass opened. The lever 19 is preferably placed in the position indicated as "suspended full blow." The piston 4 reciprocates idly until the motor and power piston have reached working speed whereupon the lever 20 is put to a vertical position to close the bye-pass. On the up stroke of the piston 4 air is compressed and passes to the reservoir 35 to build up pressure and air is sucked into the chamber 23. The latter air is on the down stroke compressed and passes to the auxiliary reservoir 47 and into the chamber 21 to elevate the ram. The movement of the lever 19 to the position marked as "full blow" results in the ram being selfacting, and if such movement is not complete a succession of light blows results. For obtaining a single blow arms 19b and 19c are turned on pivots and the lever 19 moved to the left to a position against the new position of a stop 19d on the arm 19b. The ram 3 remains suspended to manipulate the work on the anvil. By moving the lever 19 to the left until it is adjacent a stop 19e on the arm 19c a maximum single blow operation results which decreases with the distance away from the stop.