Patent ID: 9016396
Filing Date: 2015-04-28
Classification: B25D,E21B

Abstract:
1. Percussion device for a rock drilling machine including a percussive piston which is reciprocally movable inside a cylinder and an impact receiving element with an impact surface (A;A′), against which the percussive piston is arranged to perform strikes in an impact direction towards a percussive tool for transferring percussive energy through shockwaves to said a percussive tool, wherein the impact receiving element includes a shockwave modifying portion which extends in a direction opposite to the impact direction as seen from a plane (P;P′) through the impact surface (A;A′), said shockwave modifying portion being formed integrally with said impact receiving element, said impact receiving surface being provided at the forward end of said shockwave modifying portion, and a damping piston arranged to engage the rear end of said shockwave modifying portion, wherein the shockwave modifying portion has a length, as seen from said plane, which is essentially the same as the length of the percussive piston.