A hand brake valve is a type of valve used in hydraulic brake systems of trains and other large vehicles. It is called a "hand" brake valve because it is operated manually by a lever or hand brake, rather than being controlled automatically.
The hand brake valve is typically located in the driver's compartment of a train or other vehicle. It controls the flow of hydraulic fluid to the brake cylinders, which apply pressure to the brake shoes or pads, slowing or stopping the vehicle.
In addition to the manual control lever, the hand brake valve may also have other features, such as a pressure gauge or a release valve to release pressure from the brake system. Some hand brake valves may also have additional safety features, such as a locking mechanism to prevent accidental or unauthorized activation.
In pneumatically braked vehicles, a hand brake valve is used to engage the parking brake in a parked position and to release the parking brake again if the vehicle is moved. The valve is actuated by a control element, generally in the form of a cam disk, which is connected to a rocking lever and which ensures that the parking brake cylinders are ventilated.
In a conventional hand brake valve the rocking lever is blocked in a shift gate so that it cannot be entered into the released position by lifting up a handle of the lever. This prevents the parking brake from being applied and may be misleading to a driver, in particular when the rocking lever is not fully engaged but appears to be so to the driver.
One solution for this problem is to provide a switch element which switches a lighting means connected to the instrument panel in a locked position of the rocking lever. This switching element reliably indicates the locked position of the rocking lever and is connected to the hand brake valve such that simple mounting and a replacement of parts are possible.
