GB908132A - Improvements in percussive tools - Google Patents

Abstract

908,132. Nailing and stapling-machines. LIESSE, M. E. Oct. 19, 1959 [Oct. 18, 1958], No. 35369/59. Class 89 (3). [Also in Group XXIII] A percussive tool comprises a striking member operated by a piston against a return-spring by the explosion of an explosive mixture which is fed into a cylinder by a hand-controlled, shiftable member, locking means being provided to prevent operation until released by the shiftable member. As shown, a piston 2 carries a striking member 12 and is movable in a cylinder 1 which has an auxiliary piston 3 having an extension 5 provided with a locking device 9 and a camsurface 6 co-operating with a make-and-break contact 7. A handle 21 has two bellows, a larger, 26, which may be charged with air and a smaller, 28, which may be charged with butane, movement of the handle to compress the bellows causing the air and gas to be charged into the cylinder through a valve 25, and further movement causing a rod 23 to release the locking device 9 and allowing a spring 4 to move the piston 3 towards the piston 2, thereby compressing the mixture and then operating the contact 7 to cause a spark to ignite the gas mixture and drive the piston 2. Air below the piston escapes through ports 20 and passes through a double wall round the cylinder for cooling purposes. A part of the air may be used to charge the bellows 26 and return the handle to the starting position, Fig. 2 (not shown). The return of the handle to the starting position opens the exhaust valve 21 and the piston 2 rises under the pressure of a spring 13. The machine may be used for nailing (as shown), clamping, marking, punching or chiselling.