Patent GB-1494210-A (GB)
Title: Tool for carrying out operations on a workpiece by the direct action of an explosive cartridge
IPC: B25C1/10
Filed: 1974-11-27
Abstract: 1494210 Welding by pressure; explosive forming AVESTA JERNVERKS AB 27 Nov 1974 [28 Nov 1973] 51451/74 Headings B3Q and B3R A tool for carrying out operations on a workpiece by the direct action of an explosive cartridge includes a first unit which holds the cartridge and has an explosion chamber having an open mouth through which the explosion of the cartridge may act against a workpiece and a second unit which includes a mechanical firing device for firing the cartridge and which is hinged to the first unit to permit reloading. In an embodiment, a gun for explosive spot welding of, e.g. a titanium sheet to a steel plate, comprises a tubular member 10 carried by a body 11 provided with a handle 2. Slidable within the member 10 is a hollow member 22 which carries at its forward end a flanged body 37 receiving the forward end of a firing pin 23 located within the member 22, the flanged body 37 being received in an enlarged end 15 of the member 10. A cartridge holding unit 3 comprises a cup like member 35 having an opening in which is located a ring 39 slidably carrying a cartridge holder 42 secured at its forward end to a hollow member 40, the member 40 being urged forwardly by a spring 44. The cup like member 35 is pivoted at 31 to the body 11 and has an extension 36 received between two ears 37a on the body and releasably secured thereto by a pin 38. The rearward end of the member 10 is screwed to a cap member 70 coated externally with rubber or plastics material and supporting a recoil buffer 75. A member 74 is held between the end of the member 10 and the buffer and slidably receives a sleeve 76 urged forwardly by a spring 78, the sleeve being received in a member 72 urged by a spring against the closed end of the member 22. The forward movement of the sleeve 76 is prevented by an abutment member 81 and the forward end of the sleeve engages the firing pin 23 which latter has an axially extending recess engaged by a pin 60. A handle 100, Fig. 3 is attached to the body in a plane normal to the plane of the handle 2 and is provided with a means for locking the member 22 respectively to the member 10, the locking means being releasable by a trigger 120. In operation the pin 38 is released and the member 35 is swung about pivot 21 into the position shown in dotted lines in Fig. 1 whereupon an explosive cartridge is inserted into the sleeve 43 and the member 35 is returned to its initial position and secured. The gun is then applied to the work and the trigger 120 operated so that the member 40 is forced into the cup shaped member 34 and the member 44 engages the work. The member 22 presses the member 72 against the member 74 and the pin 23 presses the sleeve 76 rearwardly to compress the spring 78. A trigger 13 in the body 11 is pressed to raise the abutment member 81 and the spring 78 thrusts the sleeve 76 and the pin 23 forwards causing the pin tip 18 to detonate the cartridge and effect spot welding. Expanded cartridge removal means may be provided on the swing- able member and instead of a frusto-conical shape for the interior of the member 40 a curved undercut shape may be employed. The gun may also be used for shaping workpieces.