GB190208155A - Improvements in Fluid Pressure Actuated Impact Tools - Google Patents

Abstract

8155. Clement, J. F. April 8. Percussive hand tools.-Fig. 1 shows one form of tool in which elastic fluid, during the forward stroke, enters the cylinder 6 through openings 15 in the valve 8. These openings communicate with the groove 14 in the valve, which, in the position shown, communicates with the groove 23 in the cylinder. The groove 23 is always supplied with the fluid by channels 16, 17. The exhaust takes place through a channel 18, valve groove 13, and a groove 24 always in communication with the external air by means of a lateral channel. When the piston 9 has passed the opening 20, the fluid passes along the channels 21, and, acting on the enlarged top of the valve, shifts it downwards. The backward stroke then takes place, the channel 18 and groove 13 then communicating with the groove 23, and the openings 15 and groove 14 communicating with another lateral exhaust channel arranged beneath and parallel to that above mentioned. The valve is forced back by the fluid entrapped in the valve, this fluid also serving to cushion the piston. In a modification, the valve is solid and slides in a chamber at right-angles to the cylinder. Fig. 9 shows another form in which the valve has two heads united by a stem 8<c>. The upper head puts the upper passage leading to the cylinder alternately in communication with the inlet aperture 17<b> and with the exhaust aperture 22<b>. The lower head puts the passage 18<b>, provided with openings 18<c>, 18<d>, alternately, in communication with the exhaust aperture 19<b> and the space 35 supplied with the motive fluid. As before, the valve is moved in one direction by the entrapped fluid, which acts as a cushion above the piston on its return stroke, and in the opposite direction by fluid passing through apertures 20<b>, 21<b> and acting on the enlarged heads 10<b> of the valve. The lower end of the channel 18<b> remains closed and the tool inoperative until the piece 40 for riveting &c. is pressed against the work. The spring-pressed sleeve 41 is then pressed back, so that the motive fluid can pass through the aperture 42 of the cylinder.