GB1352065A - Cartridge actuated tools - Google Patents

Abstract

1352065 Jointing by stamping DEFENCE SECRETARY OF STATE FOR 21 Jan 1972 [21 Jan 1971] 2900/71 Heading B3Q Exhaust noise is reduced in a cartridgeactuated tool by delaying release of exhaust gas until it has cooled sufficiently to escape at sub-sonic velocity. As illustrated, the invention is applied to crimping tools in which the cartridge is fired electrically or by a striking pin. As the gas cools sufficiently in less time than it takes to operate and release the trigger 21, Fig. 2, release of the trigger is arranged to uncover an exhaust port 17. The tool includes a breech body 2 on which a stock pivots at 12 to expose a cartridge chamber 5. A grid 10 in the end of the chamber 5 retains the charge in the chamber, which opens into a cylinder 3 for a tool piston 4 having one or more rings of synthetic rubber or PTFE-bronze. An exhaust port 16 in the cylinder opens into a valve chamber 19 containing a valve 18 which is operated by the trigger 21, to close port 17, before a firing mechanism is operated. The trigger is connected by a rod 28 and a sear 30 to a hammer 29 for operating a striker 32. A safety catch 24 has a cam 23 in the way of an extension of the valve 18 for preventing operation of the trigger, or returning it in the event of sticking. In another form, Fig. 3, the pivoted connection 46 between the stock and breech body is off-set from the tool-axis, and the cartridge holder 5a engages screwthreads in the breech body. The exhaust port 16a is closed by a valve 52, 54 having a recess 56 engaged by a safety plunger 58 which is operated by the trigger 21a. Thus only after release of the trigger can the valve be withdrawn to allow communication between exhaust ports 16a, 51. The trigger is connected to a sear 60 which is located by a pin 61 and arranged to cock the hammer 64. A projection 66 of the sear is struck by the hammer during firing.