MIL-S-62549 Semitrailer, Low Bed, 40 Ton Nominal Payload For Transportation Of Heavy Engineer Construction Equipment, M870A2This specification covers a level frame, low bed semitrailer equipped with a folding gooseneck for front loading and movement of heavy engineer construction equipment.

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MIL-S-62549(AT)

3.4.7 Folding gooseneck. The gooseneck shall be of full width of the semitrailer and with tapered approach ramp for safe loading of equipment. A hinged connection between the load carrying portion and the gooseneck deck shall permit the gooseneck to be laid on the ground in a prone position, to form a continuous full width ramp and loading approach to the semtrailer deck. A locking arrangement shall be provided to enable the gooseneck to be held erect in a fixed gooseneck type position. The folding gooseneck shall have a failsafe mechanical lock for

transport and be non-binding during lowering and raising. The locks shall be safe and not deform in transportation, including front trailer supports complying with the performance and adjustment characteristics of SAE J701. A means of lubrication shall be provided for all moving parts and components.

3.4.8 Flooring. The platform shall be floored with hardwood in accordance with Class 1 of MIL-W-3912 and be capable of withstanding crawler tractor grousers and sheeps-foot rollers. Flooring shall be fastened to the frame in a manner without perforating the main frame rail. The wood surface shall be at least 3/8 in higher than adjoining metal members to prevent

metal-to-metal contact of load and semitrailer. Flooring shall be laid lengthwise, as close together as practicable, attached with corrosion resistant countersunk bolts and bridge style floor clips to eliminate drilling frame members. The top of countersunk bolt heads shall be no less than 1/8 in and not more than 1/4 in below the top of the wood surface. Center inlaid floor shall be removable and of appropriate size to provide planks for a level load bearing surface when placed on outriggers. Wood shall completely cover the gooseneck except for the stowage compartment.

3.4.9 Wheel well covers. Wheel well covers shall be provided to service the wheels. There shall be no interference between the tires and platform or wheel well covers when the semitrailer

is loaded to specified payload and subjected to the suspension system articulation specified herein.

3.4.10 Storage area. The storage area shall be provided to accommodate the various equipment and tools necessary for operation. It shall be provided with drain holes. The storage area shall be of sufficient size and 3 capacity of minimum nine cubic feet (ft3 ) and shall provide storage for eight load binders, eight chains, and a crow bar.

3.4.11 Kingpin. The semitrailer shall be equipped with a floating type kingpin conforming to the dimensions specified in SAE J848. The kingpin retainer shall be constructed so as able to withstand a drawbar pull specified in SAE J133.