GB191412194A - Improvements in Pneumatic Impact Tools. - Google Patents

Abstract

12,194. Burlingham, W., and Weaver, J. B. May 18. Percussive hand tools. -The tool is provided with tandem high and low pressure cylinders 13, 2 formed in an extension of the handle and a separate casting which are connected together by a screwed collar 5, and is provided with a receiver comprising longitudinal connected bores 25. High - pressure and low - pressure air together effect the operative stroke of the piston, and low-pressure air alone the return stroke. The distribution is effected by two parallel differential valves 22, 23 comprising pairs of large and small heads placed beneath the high-pressure cylinder and shown diagrammatically in Figs. 1 and 2. The supply fluid has constant access to the areas between the central heads. The valve 22 is reversed bv high - pressure fluid from the high-pressure cylinder; the valve 23 is reversed by receiver pressure. During the reciprocation of the main differential piston, the large valve ends are put into communication with the exhaust by a recess 17 in the piston. In the position shown in Fig. 1, highpressure air enters the cylinder 13 by passage 33 and chambers 9, 34, 32, and receiver-pressure air enters the annular space of cylinder 2 by passages 41, and chambers 40, 38, 39. The front end of cylinder 2 exhausts through passages and chambers 63, 62, 61. In the position shown in Fig. 2, the high-pressure cylinder exhausts through passages and chambers 44, 42, 40, 41 to the receiver 24, and through passages and chambers 65, 64, 62, 63 to the forward end of the cylinder 2.