Air brake for lorry and trailer - has test position on handbrake valve for releasing trailer brake only

摘要

The air brakes for the lorry and trailer are fitted with spring loaded hold-off cylinders which apply the brakes if the supply pressure drops below a set value, and which enable a parking brake to be applied. The control valve for the parking brake has an intermediate test position in which the trailer brakes only are released, while the lorry brakes remain on. This enables the driver to test the trailer brakes after connecting the trailer, without any danger of the vehicles running away on hills. The valve has an isolating element between the lorry and trailer brake outlets, with a third valve seat.