GB1358599A - Gun for firing tacks - Google Patents

Abstract

1358599 Nail driving tools U MONACELLI 13 Dec 1971 [22 Dec 1970] 57745/71 Heading B4C A tool for driving headed nails into a workpiece includes members for supporting the head of a nail being driven during the driving stroke of a nail driving element and means permitting the members to be automatically moved to a non-supporting position towards the end of the driving stroke of the element. In a first embodiment (Figs. 1 and 2) the tool is pneumatically operated and comprises a magazine 3 from which nails 28 are advanced by a spring biased pusher into a driving channel 22 along which the nails are driven by a pusher rod 12 secured to a piston 11. Jaws 20 supported the pusher rod have bent ends 21 which in the initial position of the pusher rod, support the head of a nail supplied to the driving channel. Depression of trigger 6 causes a valve 9 to be raised thus permitting supply of compressed air into cylinder 8 to drive the piston 11, the supported nail and the jaws towards the workpiece. The jaws each travel in a respective channel 23. After a predetermined distance the bases of the channels 23 diverge, so that the jaws under bias of spring 17 can pivot out of supporting engagement with the nail. At the point of release of the nail, the shank of the nail preferably extends into a workpiece (Fig. 8, not shown). In a similar arrangement (Fig. 9) a tooth 35 on each jaw engages a stop 37 which engagement assists in moving the jaw to its non-supporting position. A further embodiment (Fig. 12, not shown) includes inclined stop surfaces (25) which assist in moving the jaws into their non- supporting positions. In the embodiment of Fig. 14, upper ends 69 of the jaws are located in apertures in a hollow rod 62 integral with a piston 83 which is slidable within piston 82. The piston 82 carries a pusher rod 57 the head 56 of which coacts with cam pistons 68 on the jaws when the latter reach the diverging bases of channels 73. In operation compressed air passes via bores 67, 86 into space 84 to maintain the piston 83 in the illustrated position. Raising of valve 59 initiates the driving stroke of the piston 82 and simultaneous movement of the piston 83. When the bore 86 comes into communication with bore 66, the piston 83 is abutting buffer 60, and air in space 84 passes to exhaust via bores 86, and 66 so that movement of piston 82 continues so as to open the jaws and fully drive a nail into a workpiece. Return of the pistons is effected by introducing compressed air into chamber 54 and exhausting air from the cylinder space above the piston 82. Initially air passing via bores 65 and 86 effects upward movement of piston 82, and the head 56 on engaging the end of rod 62 effects upward movement of the piston 83.