GB1106678A - Pneumatic nailing machine - Google Patents

Abstract

1,106,678. Nailing machines. K. REICH. 30 June, 1966 [9 July, 1965], No. 29405/66. Heading B4C. A pneumatic nailing machine has a perciussion piston 9, Fig. 1, movable in a main cylinder 5 communicating via an inlet valve with a compressed air supply line 10, and with a reversing valve 49 which at the end of each blow of the percussion piston on a nail 16 is moved from a normal to a reversing position in which it causes the piston to be returned to its inactive position. When it arrives in this position it is automatically returned to its normal position in Which the piston strikes another blow on the same nail. A compressed air inlet valve, actuated by compressed air, has a large flow passage controlled via a control channel by a control valve 54, and the reversing valve 49 is interposed between two sections of the control channel of the control valve. As described the machine comprises a cylindrical housing 1 containing two concentric cylinders 4, 5, which form chambers 6, 7, 8. The outer chamber is directly connected with the air line. The upper part of the main control has a slide valve 27; when this is open an annular chamber 37 communicates via apertures 26 in the outer cylinder with the compressed air source. The chamber 37 communicates with the main cylinder chamber 8. In operation, when a trigger 76 is pulled a valve port 68 of the control valve 54 is closed. Compressed air acts on the front 28 of the slide valve 27 and shifts it upwards, the air passing into the chamber 8 and propelling the piston 9 so that the striker pin 11 hits the nail 16. During the power stroke of the percussion piston 9 the reversing valve 49 is maintained in its normal position. When the trigger 76 is pulled and the pressure in the chamber 7 reaches a predetermined strength at the end of a stroke, the reversing valve piston 56 is mounted upwards along a port 51 arid opening a port 52. The compressed air then passes from the outer chamber 6 via the valve 49 into a chamber 39 to close the slide valve. Compressed air in the chamber 7 passes into the lower part of the chamber 8 to propel the piston 9 back to its neutral position. When the striker pin 11 emerges from the bore 13 the differential piston 56 is moved back, the reversing valve 49 returns to its normal position and the cycle continues until the trigger is released. After the control valve 54 is returned to its inactive position, compressed air is permitted to escape via a choke bore 73. In modifications, the reversing valve is held in normal position by a spring 156, Fig. 2, and the control valve 54 may be returned to neutral positon by compressed air pressing open the valve member 66 when the trigger 76 is released. The valve 78, actuated by the piston 9 when at the lower end of the chamber 8 may be connected to the nail feeding mechanism by a conduit 77, so as to feed a new nail when the valve 78 is closed. The nail is held in position by jaws 17.