Abstract: A percussive device for creating impact impulses, which device comprises a housing accommodating a striker. The striker has a tail portion located in a power cylinder which is joined to the housing and is filled with a fluid medium under pressure, said fluid medium operating the striker. Provision is made of an arresting mechanism which is kinematically connected to a drive designed to engage the striker for effecting its backward stroke in the process of which the fluid medium under pressure is compressed, storing potential energy. According to the invention, the striker backward stroke drive is constructed in the form of several hydraulic cylinders equidistantly spaced round the periphery of the housing. The rod of each of the hydraulic cylinders is connected to the striker arresting mechanism.

Abstract: An apparatus for drifting openings in hard rock incorporating a carrier capable for travelling along the floor of the opening. A means of breaking of the percussive type is mounted on the carrier by means of a turnable jib with provision for turning about said jib in a vertical plane. There is also incorporated a means of loading with a mucking conveyor. Employed as the means of breaking with a percussion tool directly acting upon the rock so as to break same when the means of breaking is set into a given position. Also provided are means of shock-absorbing which serve to link up movably said means of breaking with said jib in order to absorb the undesirable deflections of the means of breaking when the percussion tool recoils from the rock at right angles to the longitudinal axis thereof and to return the means of breaking into the given position.