Top closure for a rectangular box

Abstract

The top closure of the present invention comprises a flexible sheet member sized to fit in covering relation over a top opening of a box. One edge of the sheet member is attached to the upper edge of one of the box walls. At least one track is positioned at one of the opposite ends of the box and an elongated shaft extends between the two opposite ends of the box. The tracks guide the shaft from an open position adjacent one edge of the box to a closed position adjacent the other upper edge of the box. The flexible sheet member is rolled around the shaft when the shaft is in its open position, and the sheet member unrolls from the shaft as the shaft rolls towards its closed position. When the shaft reaches its closed position, it engages a plurality of flaps which are mounted along the edge of the box. These flaps wrap around the shaft as the shaft rotates, and become attached to the shaft, thereby fastening the shaft to the sidewalls of the box with the tarpaulin in covering relationship over the opening. Reversal of the rotational direction of the shaft causes the flaps to unroll and detach from the shaft so that the shaft can roll back towards its open position, and thereby uncover the opening in the box. The shaft may be rotated either by an electrical motor or by a manual crank. The motor has a gear box which functions as a brake against rotation when the motor is deactuated.