Abstract: A device for supporting and electrically contacting brushes, with which an electrical loop contact can be established with slip-rings on a shaft of a current generator or an electric motor. The device includes a support having a support base and a plurality of pins fastened thereto, through which at least one brush can be connected supportively with the support base. The device has at least one current distributor which can be electrically contacted in a short-circuiting manner with at least two brushes and can be connected to at least one electrical connection line. More than one of the pins function as an electrical contact pin with a contact surface and are integral components of at least one current distributor, so that at least one brush can be connected supportively through it and electrically contacted. The supporting base is electrically insulated at least in regions of connecting locations to the contact pins.

Abstract: In a mine roof support in which a roof shield, pressed by hydraulically operated, collapsable and extensible props, arranged between the roof shield and a sole plate, against the roof of a mine gallery, is connected at its rear end to a rear shield, which in turn is connected by links to the rear end of the sole plate and in which a hydraulically operated cylinder-and-piston unit is interconnected between the roof shield and the rear shield for controlling the included angle between these shields, an arrangement for stopping further feeding of pressure fluid into the props when the inclined angle between the shield reaches a predetermined minimum or maximum angle.

Abstract: An advancing excavation roof support has a base and a shield assembly above the base. The base has two base portions which are spaced from one another at its end which faces toward the face of the excavation, and a lifting member is mounted between the two base portions for pivoting about an axis. A hydraulic cylinder-and-piston unit extends between the base and the lifting member and pivots the latter about its pivoting axis between a retracted position in which the lifting member is out of contact with the excavation floor, and an extended position in which an engaging portion of the lifting member engages the excavation floor and is downwardly spaced from the base so that the one end of the base which faces the excavation face is elevated and digging thereof into the excavation floor is prevented.