GB834293A - A tool for driving pins, rivets or other fastening elements - Google Patents

Abstract

834,293. Explosively-actuated pin driving tools. SCHULZ, W. Feb. 22, 1957 [Feb. 23, 1956(2); April 24, 1956], No. 6097/57. Class 119 [Also in Group XXIII] An explosively-actuated pin driving tool incorporates means for causing the pin to be elastically intercepted so as to limit the penetration of the pin into a wall or other part. In one form pin interrupting jaws 3, Fig. 1, are secured by a spring clip 4 to a member 17 axially slidable on the barrel 1. Before firing a sleeve 2 with its shutter guard 14 is pressed forwardly to retain the jaws 3 in the closed position so as to intercept the pin 5 on firing. If the pin 5 is driven into soft material, the jaws 3 will be entwined therewith together with the member 17 thus compressing a spring 20. The spring 20 may be replaced by a rubber spring or an air cushion. In another embodiment, Fig. 3. the propulsive effort acts on a piston 22 in which is located a collet-like chuck 23 for holding the pin head 27, the chuck 23 having a reduced front end 26 of less diameter than that of an opening 29 in the end of the barrel. On firing into hard material, a strong rubber ring 31 absorbs the momentum of the piston 22 when or just before the pin reaches its full depth of penetration. In this position, only the reduced end 26 of the chuck 23 will have entered the opening 29, and the jaws can open and permit the tool to be withdrawn. If, however, the pin is driven into soft material, the larger diameter of the jaws would enter the opening 29 and he retained thereby in the closed position, and at the same time a strong spring 32 is compressed to limit the penetration of the pin. In a further construction use is made of a gas cushion created by compression of the explosion gases. Inside an outer barrel 51, Fig. 4, is a second inner barrel 52 enclosing a main chamber in which a driving piston 54 can slide. The piston 54 is screwed into a metal block 57 slidable in the barrel 51, which block transfers the momentum of the piston to a pin connected to the block as described with reference to Fig. 3. Rods 60 connect the block 57 and hence the piston 54 to an annular piston 59 which slides in the space between the two barrels. On firing a cartridge in the chamber 55 the explosion gases propel the piston 54 and block 57 to the left to drive the pin into the wall. As soon as the rear end of the piston 54 reaches ports 61 in the barrel 52, the gases escape into the space between the barrels 51, 52. The ports 61 are then immediately closed by the annular piston 59 further forward movement of which compresses the gases and hence the further forward movement is braked. Embodiments are also described, Figs. 5. 6 (not shown) in which the braking spring or gas cushion for the pin is used to exert an extractive pull on the pin after firing thereby to test the strength of its anchorage in the wall.