MIL-T-62735 Trucks And Truck Tractors: Modified Commercial, General Specification ForThis specification covers general requirements for the classes, models and types of modified commercial trucks indicated in the specification title above and in 1.2 below. This specification is intended only as a document to be referenced in detail specification sheets that must, as a minimum, cover detailed truck body requirements and specify the model and class required from table I.

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MIL-T-62735

3.4.2.14 Hydraulic lift fifth wheel. When specified (see 6.2), model 4x2 and 6x4 shall have a hydraulic lift fifth wheel. The truck tractor shall conform to 3.4.2 through 3.4.2.13 and all options therein specified in acquisition documents. The hydraulic fifth wheel shall be designed, warranted and marketed for highway use. The unit shall include a hydraulic system to elevate

the fifth wheel; a pneumatic system to open a semiautomatic lock for the kingpin; all controls in

the cab, accessible to the seated driver; controls identified in accordance with 3.10.5; and all necessary components, such as pump, hoses and fittings. The fifth wheel shall have a manual locking device to lock out lifting capability. The cab instrument panel shall have a decal or plate conforming to 3.10.5 reading "LOCK DOWN FIFTH WHEEL FOR HIGHWAY USE." In addition, the vehicle shall be equipped with air brake-PTO interlocks, requiring the parking brakes to be set before the PTO can be powered. Opening the kingpin lock shall require simultaneous operation of two controls, spaced so as to require two hands by the operator.

3.4.2.14.1 Hydraulic lift capacity and range. The fifth wheel shall have a capacity of not lese than 22 100 kg (50,000 pounds) over a lifting range of at least 300 mm (12 inches). Full lifting range shall not cause the centerline of the fifth wheel to shift more than 180 mm (1 inches) longitudinally.

3.4.2.15 Air lift fifth wheel. When specified (see 6.2), the truck tractor shall have an air lift fifth wheel. The truck tractor shall conform to 3.4.2 through 3.4.2.13 and all options therein specified in acquisition documents. The air lift fifth wheel shall be designed, warranted and marketed for highway use. The fifth wheel shall have a manual locking device to lock out lifting capability. The cab instrument panel shall have a decal or plate conforming to 3.10.5 reading "LOCKDOWN FIFTH WHEEL FOR HIGHWAY USE." In addition, the vehicle shall be equipped with air brake-PTO interlocks, requiring the parking brakes to be set before the PTO can be powered.

3.4.2.15.1 Air lift capacity and range. The fifth wheel shall have a capacity of not less than 18 150 kg (40,000 pounds) over a lifting range of not less than 280 mm (11 inches). Full lifting range shall not cause the center of the kingpin lock to shift more than 75 mm (3 inches) measured longitudinally.

3.4.2.15.2 Air lift fifth wheel components. The air lift fifth wheel shall include:

(a) Additional air reservoir(s), not less than 210 liters (L) (7.4 cubic feet) total capacity, equipped with drain, safety and check valves between compressor and reservoir

(b) Automatic moisture ejector valve