GB828945A - Automatic nail gun - Google Patents

Abstract

828.945. Nailing apparatus. LAUCHER, R. G. May 2, 1957 [May 3, 1956], No. 14057/57. Class 89(3) A nail gun comprises a hammer rod 19, Fig. 1 movable from a cocked position in a work direction under influence of fluid pressure, support means 36 for carrying a nail 29. in an elevated position with respect to the work surface 43 and in driving alignment with respect to the hammer rod, and shearable means for resisting movement of the hammer rod in its work direction until the fluid pressure directed against the hammer rod is sufficient to cause the hammer rod to shear the shearable means and permit conversion of potential energy of the fluid pressure to kinetic energy of the hammer rod and nail. As described, the shearable means is a ribbon 30, Fig. 8, comprising a series of nail head washer members 32 separated by index grooves 31, each washer member carrying a nail 29. The gun is actuated by depressing a trigger 49 which admits fluid pressure from a supply passage 68 in the handle 14, into a chamber 57a, through a port 76 and into a chamber 15. The pressure in the chamber 57a forces down a hollow piston 54 which through a lever 79 moves a rail indexing rod 27 against a compression spring 48 whereby a pawl 44 carried by the rod 27 rides over the head of the next nail to engage an index groove 31, Fig. 8 in the ribbon 30. The pressure in the chamber 15 acts upon a piston 17 carried by the hammer rod 19 causing the lower end of the rod to engage the head of the nail 29 aligned therewith and this pressure continues to build up until it is sufficient to shear a washer 32 from the ribbon 30 so that the rod 19 and nail 29 carrying the washer 32 move downwardly to drive the nail into the work surface 43. A knife 42 carried by the rod 19 cuts off the end of the ribbon from which a washer 32 was cut on the previous nail driving operation. When the trigger 49 is subsequently released, it moves upwardly under the influence of fluid pressure and exposes cross ports 71, Fig. 6 in the hollow piston 54. The ports 71 comprise suction orifices through which fluid in the chambers 57a and 15 is withdrawn due to the flow of fluid pressure from the passage 68, through ports 70, along a passage 59, nozzle 60 and passage 58 to the atmosphere via the lower part of the housing 13. Low pressure is thereby developed in the chambers 15 and 57a so that the pistons 17 and 54 return to their uppermost positions as shown in Fig. 1 in preparation for the next nailing operation. Upward movement of the piston 54 allows the index rod 27 to move to the left to the position shown in Fig. 1, assisted by the spring 48, so that the ribbon is indexed by the pawl 44 to move the next nail into axial alignment with the rod 19. The nail ribbon 30 is slidably carried by a U-sectioned nail cartridge 33.