GB190119196A - Improvements in Pneumatic Hammers. - Google Patents

Abstract

19,196. Shaw, C. H. Sept. 26. Percussive hand tools.-Fig. 1 shows a longitudinal section, and Figs. 3 and 4 transverse sections on the line 3-3, Fig. 1, with the distributing-valve 29 in different positions. The air, gas, or other fluid under pressure reaches the space 34 through the channel 15, provided with the throttle valve 16 closed by a spring 20 and opened by the thumblever 23 and a second lever 18. The space 34 communicates with the annular groove 56 in the valve casing 4, which has other annular 'grooves 54, 55, 57, 58, of which the grooves 54, 58 always communicate with the exhaust through openings 43, 41. The groove 55 communicates with the bottom of the larger part of the cylinder 1 through channels 60, 42, and the groove 57 communicates with the top of the cylinder through openings not shown. The valve 29 is tubular, and slides over the fixed part 33. The valve has two wide annular grooves 50, 51 separated by a flange. Openings lead from these grooves into the interior of the valve, which is thus always full of air under pressure. The space 48 behind the valve is always free to the external air. The port 38 is always in communication with live air through channels 37, 59. The piston has a shoulder and an annular groove During the forward stroke, in which the valve and piston occupy the positions shown in Figs. 1 and 3, air enters the top of the cylinder through the grooves 56, 50, 57, and the space 62 below the shoulder communicates with the exhaust through channels 42, 60, 55, 51, 54, 43. The space 63 below the end of the piston is always open to the external air through the opening 42<1>. At the end of the forward stroke, live air passes through the port 38, the piston groove, and a channel to the space 28, Fig. 4, and thus forces the valve into the position shown in Fig. 4. During the return stroke, the top of the cylinder communicates with the exhaust through grooves 57, 50, 58, 41, and live air reaches the spaces 62 by channels 56, 51, 55, 60, 42 The valve returns to the position shown in Figs. 1 and 3, when the channel 40 is allowed to communicate with the space 63. The top of the cylinder may be in two parts, the part 2 and an internal lining 3 externally grooved to form the channels 37, 42. The tool shank has a rounded collar 46<1>, which may be forced past the pins 45, which are held in place by a spring ring 46.