|Abstract: ||A method and means of minimizing the effect of elastic valve recoil in
impact applications, such as percussive drilling, where sliding spool
valves used inside the percussive device are subject to poor positioning
control due to elastic recoil effects experienced when the valve impacts
a stroke limiting surface. The improved valve design reduces the
reflected velocity of the valve by using either an energy damping
material, or a valve assembly with internal damping built-in, to
dissipate the compression stress wave produced during impact.