Patent ID: 7540701

Claim:
A cargo transportation box body for a container or the cargo bed of a truck with a cargo-handling device for cargo unloading or loading, the box body comprising on its bottom a floor board movable via a cylinder in an antero-posterior direction, and a movable partition wall on the floor board such that, when the movable partition wall is latched, only the floor board is movable, and when the movable partition wall is not latched, the movable partition wall moves in association with the floor board, and wherein; first and second rotary bodies are attached at on the sides of and beneath the movable partition wall so as to be one on each side, and third and fourth rotary bodies are similarly attached on the sides of the movable partition wall such that the first and third rotary bodies come into proximity on one side while the second and fourth rotary bodies come into proximity on the other side; a mid portion of a first chain comprising a series of rings is wound around the first and fourth rotary bodies while a mid portion of a second chain comprising a series of rings is wound around the second and third rotary bodies such that the two chains are stretched between the respective two rotary bodies; the first and second chains are stretched between the first and fourth rotary bodies and the second and third rotary bodies, respectively, and a sprocket that engages with the first and second chains is provided between the first and second chains so as to be rotatable around an axis; the first chain with an other end thereof being fixed at a front end side and the second chain with an end thereof fixed at a front end side of the box body and another end thereof being fixed at a rear end side are stretched to cross each other so that mid portions of said chains engage with said sprocket; a rotation arresting mechanism attached to the axis of the sprocket so that a motor, when inactivated, serves as braking mechanism for arresting a rotation of the sprocket; one set comprising the first chain engaging with the first and fourth rotary bodies and the other set comprising the second chain engaging with the second and third rotary bodies form a stack such that, when one set engages with the sprocket, the movable partition wall is fastened to the box body and when the other set engages with the sprocket, the movable partition wall is fastened to the floor board or the floor board is fastened to the movable partition wall; and a stretch of each of the first and second chains from the fixed terminal end to the initially encountered rotary body is housed in a groove with a laterally opened slit provided over the floor board along a basal lengthwise corner of the box body.