MIL-T-62145 Trucks: Elevating Body, Diesel And Gasoline Engine Driven, 21,000 To 39,500 Pounds Gvw, 4X2 And 6X4, CommercialThis specification covers diesel and gasoline engine driven four-wheel, two-rear-wheel drive, and six-wheel, four-rear-wheel drive vehicles having minimum gross vehicle weights GVW of 21,000 to 39,500 pounds, for normal operating conditions. The vehicles are commercial trucks equipped with stake and platform or van bodies, capable of elevating the body and cargo to a specified height for loading and unloading the cargo into and out of aircraft. The vehicles procured under this specification are commercial items which shall be warranted by the manufacturer as specified in acquisition documents.

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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