| 摘要 |
<p>Disclosed is a positive-pressure air brake system for a highway tractor and trailer combination in which the conventional mode of tractor-to-trailer control line connection is avoided and supplanted by a sub-system in which the trailer control line pressures are developed from the tractor supply line rather than its control line through a valve assembly which responds to tractor control line pressures in relay fashion to dispense brake-operating pressures to the control line of the trailer. This valve assembly is further disclosed as having mechanism for sensing differences in the pressures of the tractor and the trailer control lines, e.g., a difference resulting from the rupture of the trailer control line, to close off the air supply to the trailer and thus bring about emergency application of the trailer brakes without any material loss of pressure in either the supply or control lines of the tractor brake system.</p> |
