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|  MIL-T-62145E
shall be provided on the discharge side of the hydraulic pump. Accumulators shall not be
furnished. The system shall be designed to a safety factor of 3 for normal operating conditions.
3.5.6.6.1 Hydraulic valving. An in-line relief valve shall be provided, fully adjustable, and
compatible with the working loads and test loads specified herein. The valve shall have
provisions for a safety lock wire on the adjustment portion of the valve to permit sealing and
locking at the proper working pressure after test. The valve shall be sealed and locked at the
proper setting after testing. A normally closed, 12-volt dc, solenoid operated check valve or
valves shall be provided to lock the cylinder(s) in the event of a failure in any other portion of
the hydraulic system. If the check valve is not integral with the cylinder, a minimum number of
fittings shall be used between the check valve and the cylinder, with a burst strength of at least
three times the maximum operating pressure. A normally open 12-volt dc, solenoid operated,
two-position, two-way valve with pilot assist or a three-position four-way valve with both
cylinder ports blocked shall be provided to raise and lower the body. The high pressure
hydraulic system shall be provided with a gage port to accommodate a 2-1/2 inch face,
0-3000 psi, glycerin filled, stem-mounted gage. The gage, when installed, shall be easily visible
with the body in the down position. The gage need not be furnished.
3.5.6.7 Hydraulic cylinders. The lift mechanism shall be actuated by single or dual
cylinders. When dual cylinders are used, they shall be connected to a hydraulic manifold in a
manner to assure equal pressure and simultaneous operation of both cylinders. Cylinders may be
single, multiple telescoping, or other special design. All seals, rings, gaskets, and other related
components shall be designed for easy removal and replacement. Metal nonflexing hydraulic
lines shall be used where flexing is not required during operation. An armored or otherwise
protected flexible hose shall be used where flexing is required. Provisions shall be made for
bleeding the system at all necessary points without removing or loosening any component of the
system. The cylinder(s) shall be positioned to prevent the cylinder(s) from extending above the
body floor. The hoist cylinder(s) shall be furnished with automatic cushioning of their stroke
when approaching the fully extended and fully retracted positions of the body. The hydraulic
system shall be designed to prevent hydraulic transients. Automatic pilot check valves shall be
provided to prevent body descent in the event of a hydraulic, electrical, or power source failure.
A manual device or valve shall be incorporated into the system to enable lowering of the body in
case of an electrical or power source failure. The device will bleed the fluid back into the
reservoir. The device shall provide metering characteristics.
3.5.6.7.1 Hydraulic cylinder valving and manifold. A check valve or a ball type shut-off
valve shall be provided between the reservoir and the return line filter to enable the shut off of
the oil supply to facilitate changing the element in the filter. A fixed orifice device or an
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