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.

Abstract: A hammer for breaking down strong abrasive materials comprising a body with a movable ram reciprocated by a drive and provided with a socket accommodating a tool intended to break down the materials by impacts during reciprocation of the ram. The end of the tool shank and the contacting bottom of the ram socket have the shape of matching spherical surfaces. The side surfaces of the tool shank and ram socket are separated by an elastic gasket and are made in the form of truncated cones whose larger base faces the working portion of the tool and angles of their cones are smaller than the angles of friction between the adjoining surfaces, the end of the working portion of the tool being provided with a blind hole which ensures better penetration of the tool into the material being broken.