This invention relates to load conveying systems, and specifically to a type of load conveying system which is known as a moving floor.
Moving floors are used in a variety of material handling environments, such as warehouses and in over-the-road trailers which are used in the trucking industry. A basic concept of a moving floor or reciprocating conveyor is disclosed in my U.S. Pat. No. 4,143,760, for RECIPROCATING CONVEYOR, which describes a moving floor system having a plurality of groups of elongated slats. In that system, a hydraulic drive is operable to move all of the slats of each group from a start position simultaneously in a load-conveying direction, and then to move the slats of each group sequentially in the opposite direction from the advanced position back to the start position. In this fashion a load is conveyed in a predetermined direction.
Known reciprocating conveyor systems utilize rigid slats which are normally formed of extruded aluminum. The hydraulic drive system typically takes the form of a plurality of hydraulic cylinders, each of which is mounted to a transversely extending drive beam or cross drive, to which are mounted each of the slats of that group. Other forms which the drive system may take include a reciprocating rod extending between a pair of fixed cylinders, or a single cylinder mounted to reciprocate on a fixed shaft. With these systems the cross drives are mounted to the reciprocating rod or to the reciprocating cylinder, respectively, and the slats of each group are mounted to one of the cross drives.
Slat type conveyor systems have been extremely successful in providing a trailer-mounted loading and unloading capability for a reasonable expense, while taking up little space in the trailer. However, because the slats must extend the entire length of the trailer, and cover most of the floor thereof, even when a light weight material such as aluminum is used, the weight of the conveyor system is substantial. Also, because the load to be carried is often dropped onto the slats in the trailer, the slats will on occasion be damaged, thereby rendering the system inoperable. Also, when consideration is given to the amount of aluminum which must be used, the expense of the slats comprises a substantial percentage of the cost of the conveyor system. Finally, in order to render the conveyor system watertight, seals must be positioned between the various slats. These seals need to be replaced from time to time and thus increase the maintenance which is required to the system.
It is an object of the invention to overcome the limitations with the prior art proposals. Other more specific objects are as follows: (1) to develop a trailer-mounted reciprocating conveyor system which does not require the use of expensive slats with seals mounted therebetween; (2) the provision of a reciprocating conveyor system which can lend itself to watertight operation; (3) to provide a conveyor system which is similar to conventional slat type conveyors except that flexible bands are used in place of the slats, such bands being less susceptible to damage during loading operations; (4) to develop a reciprocating floor conveyor system in which slats may be operating in purely a pulling rather than a pushing mode, thereby reducing structural requirements for the slats; (5) the provision of a trailer-mounted conveyor system which uses less space and weighs less than conventional slat type conveyor systems; and (6) to develop a conveyor system which permits drive components to be mounted at various positions in or under the trailer, thereby providing a conveyor system which is usable in many different applications.