Sequential latch for palletized cargo
An aircraft cargo handling system has a pair of load restraining rail assemblies, each of which has a shaft assembly running substantially parallel to the longitudinal axis of the aircraft. The shaft assembly has a plurality of lock pawls, each of which comprises a body having a cylindrical pallet-engaging surface. The pallet engaging surfaces of the lock pawls have increasing included angles at stations moving toward the front of the aircraft (or vice versa). This enables the pallets to be locked in place sequentially by rotating the shall assembly a predetermined angular rotation each time a pallet is loaded. Unloading of the aircraft is carried out in the reverse order, by rotating the shaft assembly in the opposite direction in steps to unlock each pallet individually as the aircraft is unloaded.
1. Cargo handling apparatus for restraining a plurality of pallets aboard an aircraft, each of said plurality of pallets having a side edge with a plurality of recesses formed therein, said cargo handling apparatus comprising:
a plurality of lateral restraint members attached to a floor section of said aircraft, each of said plurality of lateral restraint members comprising a body having a lateral surface and an upper surface, said lateral surface and said upper surface engaging the side edge of one of said pallets adjacent to one of said recesses for restraining lateral and vertical motion of said pallet;
a shaft assembly supported by said plurality of lateral restraint members for rotation about a rotation axis substantially parallel to a longitudinal axis of said aircraft;
first and second lock pawls attached to said shaft assembly, each of said first and second lock pawls comprising a body having a pallet-engaging surface comprising a substantially cylindrical segment having a center that is coaxial with the rotation axis of said shaft assembly and a predetermined included angle, the included angle of said first lock paw being larger than the included angle of said second lock pawl.
2. The cargo handling apparatus of claim 1 , wherein: said shaft assembly is rotatable for sequentially engaging said first and second lock pawls with one of said plurality of recesses.