摘要 |
<p>A dual circuit brake valve (10) is provided with a delivery differential control mechanism which controls the differential between the delivery pressures of the primary (70) and secondary (114) braking circuits. The delivery differential control mechanism (116) includes a spring retainer (122) which is mounted on the end of the stem (86) of the relay valve and which receives a spring-biased plunger (130). The plunger engages with the actuating member during the brake application to thereby transfer the force of the spring (132) to the relay member and therefore to the valve members of the secondary circuit. This transfer of the spring force reduces the crack open pressure of the valve members controlling communication through the secondary circuit, to thereby reduce the differential between the pressures generated by the primary and secondary circuits.</p> |