TM 5-3610-253-14
Pump. Located in the reservoir pillar and driven by the main drive motor
through a V-belt and pulleys. The pump draws hydraulic fluid out of the reservoir
through a filter and supplies it under pressure to the hydraulic system via two
ports, P1 and P2.
b. Control block. Located beside the reservoir pillar, it controls the activation
and force of the clamp and the main drive clutch ram. It is comprised of:
control unit during foot pedal operations by opening if the safety pressure is
exceeded.
(2) Clamp control valve. Controlled by a cam on the clamp pedal. When
activated it directs P1 pump flow in control unit to allow clamp cylinder to
extend with a maximum force, not to exceed the safety pressure.
(3) Conical valve (Y315). When open, allows
hydraulic oil to flow to the
clamp cylinder. The valve is open during foot pedal
operations, and downward knife
motion. During the knife's upward motion, the valve
is closed to lock the clamp
down until the knife reaches the top of its stroke.
Then the valve is open to allow
hydraulics to flow back to the reservoir.
(4) Ball valve (Y27). This valve is open when not energized to allow free
hydraulic flow through the control block. This valve is energized and closed when
the cutting buttons are depressed. Closing the valve allows hydraulic pressure to
build up in the control block to activate the slide valve. This will allow maximum
clamp pressure as set by the clamp pressure regulation valve. Once the slide valve
is fully activated, the hydraulic fluid is then routed to the clutch to allow
cutting.
(5) Clutch pressure valve. Is an adjustable valve that regulates pressure
of P2 pump flow to clutch. The valve opens and releases flow if a preset pressure
is exceeded.
(6) Clamp pressure regulation valve. An adjustable valve controlled by the
clamp pressure control pedal. Varies the P1 pump flow pressure and, therefore,
varies the clamping pressure during cutting operations.
(7) Slide valve. Controls the fluid flow in the control unit. During idle
pump flow passes through slide valve and back to reservoir. When solenoid valves
are activated, P2 pressure increases and forces slide valve up. When this occurs,
P2 flow is routed out P2K port to engage the clutch ram. P1 flow is directed to the
clamp cylinder and controlled by the pressure regulation valve only, bypassing the
clamp control valve. The output of pressure to P2K is delayed slightly (the time it
takes the slide to be moved) which allows the clamp pressure to build up first.
(8) Speed control valve. Controls the clamp's downward speed when using the
clamp foot pedal by regulating the hydraulic flow. Can be adjusted for faster or
slower operation.
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