Bendix Commercial Vehicle Systems SR-1 SPRING BRAKE VALVE - Manual (Page 3)

3
FIGURE 5 - PARKING BRAKE SUPPLY DELIVERY LESS THAN 95 P.S.I.
FIGURE 4 - RESERVOIRS CHARGING - ABOVE 55 P.S.I.
OPERATION - CHARGING SPRING BRAKE
ACTUATORS LESS THAN 95 PSI
With the air brake system charged and the dash valve
pushed in, air enters the Bendix
® SR-1 ™ valve supply port.
Air entering the supply port fl ows past inlet and exhaust
valve B to the underside of piston B and out the delivery
port of the SR-1 valve to the Bendix
® R-14 ® parking relay
valve then to the emergency air connection at the spring
brake actuator. Note that the springs above piston B force
it into contact with inlet and exhaust valve B. In the position
shown the exhaust is closed and the inlet is open.
OPERATION - CHARGING SPRING BRAKE
ACTUATORS ABOVE 95 PSI
When air pressure beneath piston B is approximately
95* P.S.I., piston B rises slightly, against the force of the
springs above it, allowing the inlet of valve B to close. The
exhaust through valve B remains closed. The closing of
the inlet portion of valve B retains approximately 95* P.S.I.
in the hold- off cavity of the spring brake actuators while
allowing full air system pressure to build elsewhere. Refer
to Figures 5 and 6.
#2 SERVICE
RESERVOIR
#1 SERVICE
RESERVOIR
DOUBLE
CHECK
VALVE
PISTON B
CHECK VALVE
INLET &
EXHAUST A
PISTON A
INLET
&
EXHAUST
B
EXHAUST
SPRING
BRAKE
#2 SERVICE
RESERVOIR
#1 SERVICE
RESERVOIR
DOUBLE
CHECK
VALVE
PISTON B
CHECK VALVE
INLET &
EXHAUST A
PISTON A
INLET
&
EXHAUST
B
EXHAUST
SPRING
BRAKE
BRAKE
VALVE
R-14 ®
RELAY
VALVE
R-14 ®
RELAY
VALVE
PARK
CONTROL
VALVE
PARK
CONTROL
VALVE