GB1076236A - Valve means for an air-operated fastener device - Google Patents

Abstract

1,076,236. Fastener driving tools. D. HAUBOLD. Feb. 3, 1966 [Feb. 4, 1965], No. 4818/66. Heading B4C. An air-operated tool for driving staples or nails into a workpiece comprises a main cylinder 5, a magnet 29 for holding a piston 14 in its uppermost position, an inlet valve 23 seating on the upper end of the cylinder, an exhaust valve 32 at the upper end of the cylinder and a trigger-operated control valve 42 for pneumatically-moving the inlet and exhaust valves, the exhaust valve being connected to a differential piston 34 operating in a cylinder 35 having a port 39 in permanent communication with an air chamber 4 and a port 40 which is in communication with the air chamber only when the control valve is in its inoperative position as illustrated. In this inoperative position, O- ring 49 is seated while 0-ring 48 is unseated to permit the air in the chamber 4 to pass through ports 53, 40 to the cylinder 35 and to pass through ports 53, 44 into the space above the inlet valve 23. When the trigger 46 is squeezed, the control valve is moved upwardly to the position illustrated in Fig. 3 (not shown), to shut-off the air supply to the space above the inlet valve and to open the port 40, together with the space above the inlet valve, to an exhaust port 54 via ports 53. The differential piston 34 moves to the right to close the exhaust valve 32. The air in the chamber 4 then raises the inlet valve against the action of springs 24 as it passes through ports 45 to force the piston 14 downwardly and drive staples from a magazine 17. During the downward movement of the piston, air is displaced through ports 11 into a storage chamber 9 and when the piston reaches a buffer 13, the actuating air above the piston flows through a port 10 to increase the pressure in the storage chamber for returning the piston. If desired, the cross-sectional area of the port 40 may be varied to regulate the time for discharging the air from the cylinder 35 and closing the exhaust valve 32.