DE2953741

PCT No. PCT/SU79/00045 Sec. 371 Date Feb. 25, 1981 Sec. 102(e) Date Feb. 25, 1981 PCT Filed Jul. 2, 1979 PCT Pub. No. WO81/00124 PCT Pub. Date Jan. 22, 1981.A reversible percussion device, having a casing 1 in which is installed a movable striker and a system for distributing fluid under pressure for causing the striker 4 to move for both forward and rearward movement functions of the device. The system comprises a control member 9 for controlling the distribution of fluid under pressure for both functions, which is movably coupled to the striker 4 and has a mechanism for locking it with respect to the casing 1 in two control positions, corresponding to the two functions of the device. According to the invention, the mechanism for locking the control member 9 in the position enabling the forward movement functions of the device comprises a body 11 movable relative to the control member 9. The body 11 is installed in such a manner as to have a portion adapted to be acted upon by fluid under pressure so as to engage the casing 1 in one position to axially lock the control member 9 with respect to the casing 1 and in the other position to enable the mobility of the control member 9 relative to the casing 1 when the device is switched over for the rearward movement function.