Abstract: This invention achieves a complete dissipation of a residual pressure in a brake cylinder. The air brake system has a pressure control valve arranged between a brake valve and the brake cylinder. This pressure control valve has an outlet valve which controls the connection between an outlet chamber to which the brake cylinder is connected, and a venting space and has a control chamber. A connection between the control chamber and the venting space can be controlled by way of a control valve. There is furthermore a connecting conduit between the outlet chamber and the control chamber of the outlet valve. In the case of a braking operation, the control valve is switched briefly into its open position after the actuation of the brake valve ceases, allowing the residual pressure in the brake cylinder to be dissipated to the venting space via the connecting conduit. The method can be employed in commercial-vehicle air brake systems.

Abstract: A pressure control valve having a pressure fluid inlet chamber connected to a pressure fluid source via a brake valve. A pressure fluid outlet chamber of the pressure control valve communicates with a brake cylinder. The pressure fluid inlet chamber and the pressure fluid outlet chamber can be connected to a control chamber via an inlet valve. The pressure fluid outlet chamber can be connected to the atmosphere via a controllable outlet valve. From the pressure fluid outlet chamber, a first connecting conduit leads to the control chamber of the inlet valve. The first connecting conduit can be monitored by a control valve embodied as a 2/2-way valve. A second connecting conduit, which is always open, is also provided between the control chamber of the inlet valve and the pressure fluid inlet chamber. This conduit exerts a delaying action upon pressure fluid flowing at high speed through it.

Abstract: An arrangement for producing grooves in walls, ceilings and the like with the use of a hand-held processing machine, has a rotatable material-removing tool driven in rotation by the machine, and a housing surrounding the tool. The housing has a guiding piece through which the tool extends. The guiding piece has a guiding surface which is adapted to lie on the surface of the wall, ceiling and the like, and is inclined at an acute angle relative to the axis of the tool. The guiding piece is detachably mounted on the processing machine.