Patent GB-722109-A (GB)
Title: Cartridge-actuated tool for firing fasteners, such as nails, into a workpiece
IPC: B25C1/12
Filed: 1951-12-28
Abstract: 722,109. Pistol-type tool. PORTABLE INDUSTRIES, Inc. Dec. 28, 1951 [Sept. 1, 1951], No. 30325/51. Class 119. A pistol-type tool for firing nail projectiles into a work piece such as masonry has a firing pin normally spaced a safe distance from the cartridge primer and means rotatable by the tool operator in one direction to move the firing pin towards the primer into a ready-to-fire position said means being movable in a different direction to effect firing. The pistol comprises a removable barrel 10b with screw breech block 16 and a  removable hexagonal chamber plug 15 for loading a cartridge 12 and a nail projectile 11. The firing pin 13 is eccentrically housed in a sleeve 25 fast with a rotary firing handle 31. The barrel and breech block are surrounded by a knurled outer casing 23 forming a grip for the operator and an intermediate rotary sleeve 18 controlled by the rotation of handle 31. A pin 19a fast with the breech block engages a cam slot 20a, 20b, 20c, Fig. 1, m the sleeve 18 and a longitudinal guide slot 23a in the grip casing 23. A main spring 38 normally presses the barrel and breech block forwardly away from the firing pin assembly. The barrel protrudes through a flash shield 40 which is connected to a sleeve 41 sliding on the barrel against the action of a weak spring 44. When firing the pistol, the shield and barrel are pressed against the masonry or other work piece and the parts brought from the normal safety position, Fig. 2, to the ready-to-fire position, Fig. 3, by anti-clockwise rotation of handle 31, the pin 35a rotating sleeve 18 and pin 19a travelling in cam slot 20c, 20b. The breech block 16 with its firing opening 17 thus approaches the firing pin but firing is precluded by the eccentric, or out of register position of the firing pin in relation to opening 17 which enables a collar 13a on the pin to strike the surface 16a of the opening to cock the firing pin against the action of its spring 29. To complete firing, the handle is rotated in the reverse direction to bring the firing pin into full register with the opening 17 and enable the pin to spring forwards and strike the primer. The flash shield may be adjusted round the barrel to enable nails to be driven in at varying distances from a wall corresponding to the readings of an index plate 51, Fig. 12. Firing of the pistol when the shield makes an angle greater than say 7 degrees to 14 degrees with the workpiece is also precluded by the permitted advance of the barrel away from the firing pin outside these limits. The pistol can readily be adapted for firing by a blow on a button 60, Fig. 18, which replaces the firing handle 31. For this purpose the pin 35a, Fig. 4, occupies a threaded opening in sleeve 25 so that by one turning movement the eccentric firing pin is brought into register with the opening 17 for direct firing by a blow on the knob, the pin 35a then moving in a longitudinal slot in the sleeve 18. The threaded front end of the barrel may receive a disc adapter enabling a mild steel disc to be pierced and carried forward by the driven nail. For driving nails down into a hole in the workpiece, a further barrel extension may be used. Reference has been directed by the Comptroller to Specification 714,931.