Brake Valve have a " (12.8 mm) supply and "
The E-4 Dual Brake Valve is a foot operated valve
with two separate supply and delivery circuits for
(7 2.8 mm) delivery port.
service and emergency braking which provide the
driver with an easy and normal graduated control
Both upper and lower circuits use a common ex-
of applying and releasing the vehicle brakes. It can
haust located at the bottom of the valve which is
be either treadle operated or fitted with linkage for
protected from foreign matter entering the valve
connection to a conventional brake pedal.
by an exhaust check valve.
The E-4 Dual Brake Valve differs from other
APPLYING
Bendix-Westinghouse Brake Valves in that it is two
valves in one; each portion (upper and lower) hav-
NORMAL OPERATION: UPPER PORTION
ing separate inlet and exhaust valves, controlling
two separate circuits, receiving their air supply from
When the pedal or treadle is depressed, force is
separate air reservoirs, and controlled by the move-
exerted on top of the piston, and rubber graduating
ment of one treadle or pedal. The upper portion is
spring. The top piston moves down, and its stem
similar to the E-3 Brake Valve in operation and uses
which is the exhaust seat, closes the upper exhaust
the insert type inlet and exhaust valve assembly.
valve. As the upper exhaust valve closes, the upper
Under normal operating conditions, the lower por-
inlet valve is moved off its seat, and air pressure
tion is similar in operation to a relay valve. The lower
flows out the upper delivery port to the brake actu-
portion inlet and exhaust valve is also of the insert
ators applying the brakes.
type and can be easily removed without discon-
necting air lines.
NORMAL OPERATION: LOWER PORTION
When the upper inlet valve is moved off its seat,
Both upper and lower portions of the E-4 Dual
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