Electropneumatic hammer

In an electropneumatic hammer comprising a housing, an axially extending guide cylinder within said housing, said guide cylinder forming an axially extending bore having a forward end and a rearward end, an exciter piston displaceably mounted within the bore in said guide cylinder, a driving piston displaceably mounted within the bore in said guide cylinder between said exciter piston and the forward end of the bore, wherein the improvement comprises an axially extending clamping member located within the bore with the axis thereof disposed in parallel relation with the axis of the bore and said clamping member secured against axial displacement in the bore, said clamping member having a first end and a second end with said second end spaced forwardly of said first end toward the forward end of said bore, said driving piston having a first part located adjacent to said exciter piston and a second part extending from said first part toward the forward end of the bore, said second part having an axially extending outer surface thereon arranged to be gripped by said clamping mamber and said surface extending through said clamping member from the first end toward the second end thereof as said driving piston reciprocates, and said clamping member having a portion thereof being inwardly movable relative to the axis of the bore through said guide cylinder under certain conditions for effecting gripping contact with the outer surface of the second part of said driving piston.