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)

3.4.18  Stake pockets.  Minimum ten each, stake pockets installed five on each side to accept four by four inch stakes with bottom stop and drainage provisions.  The stake pockets shall be equally spaced from front to rear of the loading space, except when interference with critical frame members occurs.

3.4.l9  Outriggers.  The semitrailer shall be equipped with folding outriggers for deck widening to 120 in.  The outriggers shall be properly located for using center inlaid flooring

planks of sufficient thickness to carry the payloads.  Outriggers are also to be provided in the area of the roadwheels and to the rear of the semitrailer to sufficiently support the plank and payloads.

3.4.20  Rear wheel splash and stone throw protection.  Anti sail mud flaps shall be provided at the rear of the rear wheels and shall be in accordance with SAE J682.  The splash and stone throw protection assembly shall be capable of being removed with ordinary personnel tools.

3.4.21  Lift fitting.  A heavy duty lift fitting, with removable pin for quick disconnect cable attachment, shall be provided and located at the center front of the gooseneck.  The removable lifting pin shall be attached to the body of the semitrailer with a corrosion resistant chain to prevent loss and its bore shall be provided with lubrication fitting.  The lifting attachment shall be capable of two times the load imposed by the unit cable.

3.5  Performance.

3.5.1  Automotive.  The semitrailer, fully equipped and loaded with rated payload, shall meet all the requirements specified herein without any evidence of part failure or permanent damage when coupled to suitable tractors and operated under the speed and slope condition specified in table III.

TABLE III  Speed and slope.

1/  M916, 6x6 Truck-tractor

2/  M920, 8x6 Truck-tractor

3.5.2  Turning ability.  The semitrailer shall be capable of assuming a 90° angle in both directions to the coupled towing vehicle without cramping, side-slipping, or damage to the semitrailer or the towing vehicle.

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