Power hammer

In a power hammer of the type which imparts successive hammer blows to the end of a tool element, the improvement comprising:

• a. rectilinear guide means;
• b. a striker piston mounted by said rectilinear guide means for reciprocal axial movement in a hammer-direction and in a return-direction, said piston serving to impart a hammer blow to a tool element as the former moves in the hammer-direction;
• c. a piston actuator mounted for oscillatory movement in a hammer-direction and in a return-direction and lost-motion means connecting said actuator with said piston such that oscillatory movement of the former, imparts the aforesaid axial reciprocal movement to said piston, said lost-motion means permitting limited axial movement of said piston relative to said actuator when the latter reaches the end portions of its stroke of oscillatory movement;
• d. a motor having a rotary output member;
• and
• e. mechanical means connecting said rotary output member with said actuator thereby to convert rotary movement of the former into said oscillating movement of the latter, said mechanical means being capable of moving said actuator in its hammer-direction at a velocity which is greater than the velocity of the actuator in its returndirection, whereby said piston is also moved in its hammer-direction at a velocity which is greater than the velocity of the piston in its return-direction.