An apparatus for generating an impact against a target object comprises a driver
reciprocally disposed in a housing. The driver includes a hollow tube having a
closed end and a nozzle seating the other end. A piston is slidably positioned
in the tube. Propellant is disposed between the piston and the closed end of the
tube and fluid is disposed between the nozzle and the piston. A rupture disc is
provided for sealing the nozzle which is adapted to rupture when the pressure in
the tube exceeds a predetermined pressure. A striker is also mounted in the housing
so that in a retracted position of the striker a head portion is proximate the
driver and a portion of a shaft extends outwardly from the housing. The striker
member is movable between the retracted position and an extended position. The
propellant is ignited so that combustion gases build pressure in the tube between
the piston and the closed end of the tube causing the pressure in the tube to exceed
the predetermined pressure for rupturing the disc. This causes the piston to move
toward the nozzle and fluid to be expelled through the nozzle for moving the driver
against the head portion of the striker. The driver transfers energy to the striker
for moving the striker to the extended position at high velocity for driving the
end of the striker with great force against the target object. Recoil action is
cushioned by the fluid exiting the nozzle.
