Abstract: The mining cutter-loader for winning minerals with a chainless feed system comprises a housing and a gantry pivotally connected with the housing, overlying the conveyor. The gantry carries propulsion mounted on the conveyer. The propulsion gears and the guiding rack are mounted in inclination relative to the axis of the housing, transverse with respect to the direction of the motion of the cutter-loader. Hydraulic cylinders are mounted between the housing and the gantry for fixing the housing relative to the gantry, having their one ends pivotally connected to the housing and their opposite ends pivotally connected to the gantry.

Abstract: A chainless feed system of a mining cutter-loader comprises a guiding rack mounted on a conveyer and meshing with gears rotatably mounted on the cutter-loader. The gears are operatively connected through a rotating mechanism with the hydraulic cylinders operable for rolling the gears along the guiding rack. The improvement of the rotating mechanism includes a carrier with a pawl adapted to engage the gear or come out of engagement therewith. For this purpose the pawl is pivotally mounted on the carrier which is operatively connected with the hydraulic cylinders arranged in opposition with respect to the pawl.

Abstract: Disclosed is a plough mining installation for the underground working of minerals, preferably those occuring in thin seams, which incorporates plough bodies interlinked by rigid rods into a ploughing system reciprocating along the face due to a reciprocatory means consisting of an immovable hydraulic ram and a plurality of movable hydraulic rams. Spaced apart along a frame of the installation, the movable hydraulic rams are linked to each other by articulated joints resting on slides arranged to travel on longitudinal guide means. Thus, the ploughing systems is capable of reciprocating through a distance equalling the length of the aggragate stroke of all the hydraulic rams.

Abstract: The pressure valve is actuated by pressurized fluid and has a housing with a high-pressure space and a low-pressure space separated from each other by a partition. The partition has a bore accommodating a valve member. Axial passages are made in the body of the valve member for establishing alternating communication between the spaces upon the displacement of the valve member. The low-pressure space receives a pressure-relief valve spring-urged away from the partition and movable by the action of pressure selectively supplied to initiate relieving of the high-pressure space. The pressure-relief piston has an axial bore. The pressure valve incorporates an auxiliary piston in the axial bore of the pressure-relief piston and it cooperates with the valve member to displace the latter. The body of the valve member is provided with throttling passages communicating with the axial passages.