GB190306295A - Improvements in or relating to Pneumatic Tools. - Google Patents

Abstract

6295. Boult, A. J., [Peck, C. W.]. March 18 Percussive hand tools; chisels.-Relates to a pneumatic percussive hand tool such as is used for chipping, caulking, drilling, reamering, &c., and more particularly to the valve mechanism of such a tool. Two sections of the tool at right-angles to each other are shown in Figs. 1 and 2, and a third section, intermediate between the other two, in Fig. 3. The barrel A, Fig. 1, is secured by the sleeve G to the handle F and chamber E containing the valve-box D and the cylindrical valve I, the interior of which forms a continuation of the working- cylinder. T move the valve, air or other fluid is admitted to, and exhausted from, the opposite sides of the flange I<1> in the chamber between the valve-box D and the flanged bush J. When the valve is in either of its extreme positions, a small port f allows air to pass into the chamber j to hold the valve in that position. At the end of the return stroke of the piston P, the reduced part p<2> enters and compresses the air in the bush J. In the Figures, the piston is shown at the beginning of its return stroke. The air passes from the duct a, through the passage c, port d, grooves n', port n, and passage h to the front of the piston, and escapes from the back of the piston through the ports i<1>, groove o, port w, Fig. 3, and passages v, x. During the return stroke, the piston closes the exhaust ports i<1>, Fig. 1, and then the passages c, g are thrown into communication with the passages r, q, Fig. 2, by means of the groove p, Fig. 1, and the valve is moved to its rearward position. The air from the back of the flange I' is exhausted through the port j<1>, Fig. 2, passages t, s, port s<1>, the space in the front of the piston, the port u<1>, Fig. 3, and passages u, v, x. The air then passes through the port e, Fig. 1, groove e<1>, and ports i to the back of the piston, and the air from the front of the piston will be exhausted through the port m, grooves m<1>, o<1>, o, port w, Fig. 3, and the passages v, x. Just before the piston arrives at the end of its stroke, the port s<2>, Fig. 2, is uncovered, and air passes from the cylinder through the passage t<1>, and moves the valve into its former position, the air from the front of the flange I<1> being exhausted through the port q<1>, passage q, groove p<1>, and port u<2>, Fig. 3. The valve L, Fig. 1, for controlling the air-supply is kept on its seat M by a spring, and the part within the seat M is provided with a series of inclined faces or bevels, which, as the valve is depressed, open the communication between the air-supply and the duct a, one after another. The regulating-valve Q, which may be turned to make the port b register entirely or only partially with the passage c, is held in any position by means of the serrated head S and the locking-bolt R.