1
Phillip R Johnson, Peter F M Prillinger, Alfred W Sieving: Control system for an integral spring-loaded parking and service brake. Caterpillar Tractor Co, Phillips Moore Weissenberger Lempio & Strabala, December 21, 1976: US03999075 (13 worldwide citation)

A control system for a spring-applied service brake which can also be used as a parking brake. Pressure from the vehicle hydraulic system is normally used to release the brakes. In the event of a loss of the primary pressure from the hydraulic system, the control system switches automatically to use ...


2
Control system for an integral spring-loaded parking and service brake. Caterpillar Tractor Co, December 21, 1977: GB1495915-A (1 worldwide citation)

1495915 Spring - loaded vehicle brakes CATERPILLAR TRACTOR CO 17 March 1976 [18 Aug 1975] 10778/76 Heading F2F Vehicle brakes 10 are biased on by springs 12 and held off by hydraulic pressure in line 35 connected to a three-position valve 19. Normally the valve is centralized (as shown) by springs 2 ...


3