High energy impact riveting apparatus and method

A method for forming an elongated metal object having opposite ends such as upsetting a fastener in a workpiece comprising the steps of:

• a) providing high energy impact apparatus comprising a pair of apparatus units operatively associated with said opposite ends of said metal object, each of said apparatus units having a mass;
• and
• b) adjusting the mass of said units to obtain a mass balance so that upon simultaneous impact by said units on the opposite ends of said metal object there occurs the least possible amount of unbalanced force so that the least possible amount of force transfers to the workpiece and to structure associated with said apparatus units.

Apparatus for forming an elongated metal object having opposite ends such as upsetting a fastener in a workpiece comprising:

• a) first and second units of high energy impact apparatus operatively associated with said opposite ends of the metal object and each comprising first and second coil means in close proximity to and in electromagnetic association with each other, the first coil means being in driving association with a forming tool adapted for forming the metal object at one of the ends thereof, the first and second coil means being supported in a manner allowing movement of the first coil means relative to the second coil means, and wherein electric current pulses are supplied simultaneously to the first and second coil means to provide a repulsive electromagnetic force sufficient to accelerate the first coil means and drive the forming tool against the end of the metal object;
• and
• b) the mass of said units being adjusted to obtain a mass balance so that upon simultaneous impact by said units on the opposite ends of the metal object there occurs the least possible amount of unbalanced force so that the least possible amount of force transfers to the workpiece and to structure associated with said apparatus units.

Apparatus for forming an elongated metal object having opposite ends such as upsetting a fastener in a workpiece comprising:

• a) high energy impact apparatus comprising a pair of apparatus units operatively associated with said opposite ends of said metal object, each of said apparatus units having a mass;
• and
• b) the mass of said units being adjusted to obtain a mass balance so that upon simultaneous impact by said units on the opposite ends of said metal object there occurs the least possible amount of unbalanced force so as to substantially eliminate transfer of force to the workpiece and a structure associated with said apparatus units.