US 20050072657 A1
Conveyor systems for storage and movement of goods on pallets and slip sheets. The transfer structures enable slip sheet mounted loads to be transferred to a roller conveyor by providing structures that cooperate with wide platen forks of a lift truck. The structures provide roller contact between a portion of the underside of the slip sheet at all times. In other areas there is alternatively contact between a lift truck platen or additional rollers that cooperate in a manner making it possible to move the slip sheet mounted load from the lift truck to an adjacent conveyor system.
1. A conveyor transfer structure for use with loads resting on a slipsheet, the transfer structure comprising:
(a) fixed-position rollers for contact with the slip sheet and
(b) movable position rollers movable between first positions supporting portions of the slipsheet and second positions permitting lift truck platen contact with the portions of the slipsheet.
2. The conveyor transfer structure of
3. The conveyor transfer structure of
This invention relates to conveyor systems for storage and movement of goods on pallets and slip sheets and, in particular, to the use of slip sheets with roller conveyor systems.
Goods are stored and shipped throughout the world in relatively uniform size loads that rest on either pallets or thin plates of pasteboard or other fiber material known as slip sheets. Slip sheets provide cost, weight, size and other advantages as compared to pallets but are not as stiff as pallets and must therefore be supported with contact over a larger portion of their undersides than pallets. Accordingly, while pallets can be lifted and transported by contact between relatively narrow regions of the pallet understructure and forks, such as conventional lift truck forks, much wider structures must be used to support slip sheets bearing loads. Transfer of loads resting on slip sheets therefore conventionally occurs by sliding the slip sheet and load between two locations by either pushing the slip sheet and load or pulling the slip sheet by grasping an edge of the slip sheet. There are numerous drawbacks associated with these activities.
As a result, it is desirable to provide improved structures and means for transferring loads carried on slip sheets on to and off of roller conveyor systems.
The transfer structures of this invention enable slip sheet mounted loads to be transferred, for instance, from a lift truck to a roller conveyor by providing structures that cooperate with wide platen forks of a lift truck. The structures provide roller contact between at least a portion of the underside of the slip sheet at all times. In other areas there is alternatively contact between a lift truck platen or additional rollers that cooperate in a manner making it possible to move the slip sheet mounted load from the lift truck to an adjacent conveyor system.
In the first embodiment of the transfer structure of this invention, illustrated in
Operation of the transfer structure embodiment shown in
After the slip sheet and load are thus resting solely on the rollers of transfer structure 10, the load can be pushed in the direction of conveyor rollers 12 and can move along the conveyor system in the conventional manner.
As will be appreciated by one skilled in the conveyor art, the transfer structures of this invention can also be used for removal of a load resting on a slip sheet by movement of the load onto the transfer structure and use of the lift truck platens in steps that are reverse in order from the above description.
Embodiment 50 also utilizes two sections of rollers 54 and 56 mounted in a manner so that they are biased by a spring, pneumatic cylinder, or other suitable structure normally to be in the position shown in
In operation of this embodiment 50, the ends of platens 32 contact stop 58 as the platens move to the right in
As described above relative to the first embodiment (20) of this invention, the pivotable rollers 20 pivot. When the load is lifted off of transfer structure 50 or platens 32 are moved out from under the load and slip sheet, the pivotable rollers 20 pivot forward to the position shown in
As will be appreciated by reference to the Figures. and description of this invention above, it can be practiced in several alternative configurations including configurations not shown in the drawings.
In general, all such configurations can provide a transfer mechanism with multiple rollers for supporting a load mounted on a slip sheet so that the load can advance on rollers in the transfer mechanism to a conventional roller conveyor structure or can advance from a conventional roller conveyor structure to the rollers of the transfer mechanism. Some of the rollers or wheels of the transfer mechanism remain fixed in a plane that is substantially the same plane as the tops of adjacent rollers of the conventional roller conveyor. Other rollers, wheels, or other support structures are positioned and mounted to move from: (1) a first position where their support surfaces are in the same plane with the support surfaces of the fixed rollers, wheels or other support structures to (2) a second position permitting the platens of a lift truck to be positioned with their support surfaces in the same plane as the support surfaces of the fixed wheels or rollers. Other load bearing surfaces substitutable for rollers and wheels can be used in appropriate circumstances, including, for instance, low friction surfaces and conveyor belts among other alternatives.