1728 Orbit Way - Minden, Nevada 89423 P: 775-782-1700 F: 775-782-1701 info@maxtonvalve.com www.maxtonvalve.com
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CAR AT REST–SOLENOID COILS DE–ENERGIZED
The car at rest is held by a hydraulic fluid system locked in place by a check valve, solenoid pilot valves and
a manual-lowering valve.
UP DIRECTION
When an up call is registered and the pump starts, the up solenoid (U) and the up stop solenoid (US) are
simultaneously energized closing the ball checks US and UT. The pump output flows through the up valve
and back to the reservoir.
Hydraulic fluid from the pump travels through the up strainer, to the up acceleration adjustment (UA), then
the control side of the up piston. The control side of the up piston is larger in area than the area of the up
piston exposed to the pump pressure; therefore, the up piston begins to move towards the up valve
restricting the opening in the up valve, raising the pump pressure. As the pump pressure increases above
that on the jack side of the check valve, the check valve is opened allowing fluid to flow to the jack cylinder
causing the jack to move in the up direction. The elevator then accelerates to full speed as the up piston
closes the up valve.
Upon reaching a predetermined distance below the floor to which the car is traveling (2 inches for each 10
fpm of car speed NOT to exceed 6 inches for every 25 fpm of car speed), the up solenoid (U) is
de-energized, allowing fluid from the control side of the up piston to flow through the up transition adjustment
(UT), then to the up leveling speed regulator (LS) orifice which is held open by a mechanical linkage
attached to the check valve. The control fluid then returns to the reservoir and the up piston moves toward
the open position. As the up piston moves, opening the up valve, hydraulic fluid begins flowing to the
reservoir, reducing the pump pressure. As the pump pressure is reduced, the check valve begins closing,
also, partially closing the (LS) orifice in the up leveling speed regulator.
When the flow through the (LS) orifice equals in quantity, the flow through the up acceleration adjustment
(UA) and the up leveling adjustment (UL), the car will be in leveling speed. Upon reaching a point slightly
before the floor (usually 3/8 of an inch to ¼ of an inch), the up stop solenoid (US) is de-energized. This
allows fluid to flow through the up stop adjustment (US), causing the up piston to fully open, permitting the
total pump output to flow to the reservoir, causing the car to stop. After the car comes to a complete stop, the
pump motor is electrically timed out and stops. If, during up movement, the car has been overloaded or hits
an obstruction, the fluid on the control side of the piston is evacuated to the reservoir through the relief valve,
causing the up piston to cycle open and by-pass the entire pump output.
OPERATING SEQUENCE UC1, UC1A, UC2, UC2A B44
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