Apparatus for generating shock waves by means of a supersonic projectile

An apparatus for generating shock waves, comprising a first vertical cylinder connectable selectively at its upper end to a source of compressed gas or to a vacuum source, a first hammer fitting slidably within said first cylinder, a first cylindrical plunger coaxial and integral with the lower end of said first hammer, a hydraulic pressure chamber communicating with said first cylinder and having an axial hole dimensioned and disposed to receive said first plunger slidably with minimum clearance, said hydraulic pressure chamber having a vent hole means above said axial hole for establishing a liquid level in said hydraulic pressure chamber when liquid is transferred in excess into said hole, a piston chamber having first and second coaxial cylindrical ends, said first cylindrical end being hydraulically connected with said pressure chamber, a piston fitting slidably within said first and second ends, said piston being continuously reciprocable within said piston chamber, said second cylindrical end and the end of said piston therein forming a gas chamber fillable with a gas of low molecular weight, said second end of said piston chamber having an exit vent, a diaphragm blocking said exit vent and being selected to burst at predetermined pressure on compression of said low molecular weight gas by said piston, a barrel having an elongated bore therethrough connected removably at one end thereof to said piston chamber at said vent, said bore at said one end and said other end of said piston chamber being gastightly connected when said diaphragm is burst, said barrel being adapted for holding a projectile slidably in said bore at said one end thereof, and a holder for holding a workpiece at the other end of said barrel, said holder being vented.