Patent ID: 8523489

Claim:
An apparatus for bursting and replacing a conduit, comprising: a stored energy and cutting head having a stored energy head cavity and a stored energy head cap closing the stored energy head cavity; an energy storing assembly including: an energy storing head rod disposed in the stored energy head cavity; a washer retainer carried by the energy storing head rod; and a plurality of cupped spring washers carried by the energy storing head rod and sandwiched between the washer retainer and the stored energy head cap of the stored energy and cutting head; and a hammer assembly carried by the stored energy and cutting head and including: a hammer assembly housing carried by the stored energy and cutting head; a hammer disposed for axial displacement in the hammer assembly housing; a spring cavity in the hammer; a hammer return spring in the spring cavity, the hammer return spring interposed between the hammer and the stored energy and cutting head; an air pressure opening in the hammer and communicating with the spring cavity; a piston cavity extending into the piston end of the hammer; an air vent opening in the hammer and communicating with the piston cavity; and a hammer driving piston adapted to engage the piston cavity in the hammer for displacement in the hammer assembly housing against the stored energy and cutting head.