MIL-T-11663 Truck, Materials Handling, Container Hoisting, Rear Hoist, 21,000 To 32,000 Pounds Gvw, 4X2This specification covers diesel or gasoline engine driven, four-wheel, two-rear-wheel drive materials handling trucks having gross vehicle weights GVW of 21,000 to 32,000 pounds, for normal operating conditions. Vehicles procured under this specification are commercial items which shall be warranted by the manufacturer as specified in acquisition documents.

Pages 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19 - 20 - 21 - 22 - 23 - 24 - 25 - 26 - 27 - 28

MIL-T-11663K

3.5.3 Hydraulic systems. The hoist-haul units shall be hydraulically operated. Power shall be transmitted from a transmission mounted power takeoff through a heavy duty gear or vane type pump. The normal operating pressure range shall be between 900 pounds per square inch (psi) and 1600 psi. Relief valves shall be incorporated into the hydraulic system to prevent excessive pressure. A line tap shall be provided so that a pressure gage may be installed to periodically check relief pressure. All hydraulic lines, hoses, and fittings shall meet or exceed the requirements of SAE recommended practices and standards. The size, volumetric capacity, and

pressure rating of all components shall be such as to assure a smooth and efficient operation of the system.

* 3.5.3.1 Hydraulic fluid. Unless otherwise specified, the manufacturer's standard or recommended hydraulic fluid shall be provided in the hydraulic system. When specified (see 6.2), hydraulic fluid conforming to MIL-H-83282 shall be provided in the hydraulic system. A permanent decal located near the hydraulic system fill port shall be furnished stating "CAUTION: USE HYDRAULIC FLUID CONFORMING TO MIL-H-83282 ONLY."

* 3.5.3.2 Hydraulic cylinders. All hydraulic cylinders shall be fitted with seals to prevent entrance of dirt, moisture, and other foreign elements and to preclude leakage of hydraulic fluid from the cylinders. Hydraulic piston rods shall be chrome-plated full length with sufficient thickness to withstand a 30-hour salt spray test in accordance with ASTM Designation B117. The connecting ends shall be treated in accordance with the best commercial practice.

3.5.3.2.1 Type I cylinders. Two vertical cylinders shall be provided to control the elevating and lowering of the boom arms. One horizontal cylinder shall be provided to control the forward and rearward movement of the carriage for container pickup, moving the container into travel position, and moving the container into position for dumping refuse.

3.5.3.2.2 Type II cylinders. One single-acting cylinder shall be provided to control lifting and lowering of the forks, two double-acting cylinders to control the dumping action, and one double-acting cylinder to control the tilting action of the carriage.

3.5.4 Lubrication. All moving parts and surfaces of the equipment normally requiring lubrication shall be provided with lubrication fittings of the hydraulic type with surface check ball and, when applied to sealed bearings, shall have pressure release to protect the seals.