Abstract:
Disclosed is a method and device for transporting materials from a shipping end to a receiving end. The device is a slip sheet formed from a flat sheet of material having a flat portion with four side edges. One of the side edges has a compressible tab portion that extends outwardly therefrom. The compressible tab portion has an elliptical lip and an upper lip that forms a convex air foil-type cross-sectional area. The compressible tab portion is canted upwardly from a plane defined by the flat portion of the slip sheet. The slip sheet can be used in combination with a captive pallet to transport materials. Further, a method of transporting materials is disclosed whereby the shipping and receiving ends house the captive pallet whereby only the slip sheet is transported by a push-pull or fork-lift type truck.

Description:
This application claims the benefit of U.S. provisional application, Ser. No. 60/124,444 filed on Mar. 15, 1999, in Express Mail Label No. EL287032906US by the same inventor, Howard J. Trickett, entitled DEVICE AND METHOD FOR TRANSPORTING MATERIALS. 
    
    
     BACKGROUND OF THE INVENTION  
     I. Field of the Invention 
     This invention pertains to the field of transporting materials and, more particularly, to transporting materials by a fork-lift and push-pull type truck. This invention eliminates the pallets commonly used in the transportation cycle and provides a better and more advantageous pallet. 
     II. Description of the Related Art 
     The present invention contemplates a new and improved method and device for transporting materials which is simple in design, effective in use, and overcomes the foregoing difficulties and others while providing better and more advantageous overall results. 
     The world population is increasing. In fact, the UN Food &amp; Agriculture Organization projects an increase of 5 to 7 billion people over the next 30 years. This is like adding a new China or India every 10 years. 
     Population increase and economic expansion consumes land for housing and infrastructure. The earth&#39;s land and its resources are limited. Science and technology have provided us with the ability to do more while using less of the available land and resources. However, science and technology are limited as to what they can provide. Mother Earth will be stressed to keep up with world population expansion. 
     Quality of life is inextricably linked to the basics: reproduction, food, housing, packaging and transportation. Technology plays a major role by providing for a better standard of living for the worlds&#39; people. However, responsible business managers must be at the forefront of developing, providing and using environmentally responsible products. 
     For over sixty years products have been placed on wood pallets and we have used forklifts to load these products into trailers, containers and railcars. In today&#39;s world of high technology this equates to farming with a pair of oxen and a shovel plow. Packaging on wooden pallets can no longer be rationalized nor can shipping the product to a customer who throws the wood pallet into a trash receptacle with the pallet ultimately ending up in a landfill. Landfills are being closed and the trees required to make a good quality wood pallet are becoming scarce thus making the wood more expensive. Today&#39;s U.S. wood pallet average cost is over eight dollars. Landfill expense pushes the total cost of using a wood pallet to about ten dollars. This cost adds to the packaging, logistics and ultimately to the consumer&#39;s cost of the products they purchase. 
     Data indicates the global market for wood pallets is in excess of one billion units annually. The data does not include remanufactured or reused pallets. This data also indicates that the U.S. uses over five hundred million wood pallets annually. About four hundred and fifteen million (83%) end up in landfills, about eighty million (16%) are recycled/reused and about five million (1%) disposed of as firewood. 
     One of the challenges being addressed is the depletion of the world forest to manufacture wood pallets which are then disposed into landfills. We will teach how to use commercially and economical feasible replacement products made from recycled material and/or commercially and economical feasible replacement products that can be recycled back into themselves. These products will be used as the material handling system for the 21st century. 
     The material handling industry is an industry seeking a change, but until now lacked an uncomplicated economical alternative to the wood pallet. The slip sheet disclosed and claimed within U.S. Pat. No. 5,613,447 and co-pending patent application, Ser. No. 08/823,698 (now U.S. Pat. No. 5,881,651) are those unpretentious economical alternatives. The use of such a slip sheet in conjunction with a captive pallet system leads the way to the future of material handling. These two items taken together, finally accomplish what so many have tried for so long to achieve. 
     A captive pallet system is one where the shipper and receiver use a good quality wood, plastic or metal pallet to handle the product in-house while the product is packaged on a slip sheet. 
     The unit of product has hereto been pulled by means of a forklift attachment called a push-pull, from the captive pallet at the point of shipment and the slip sheet becomes the article of conveyance to transfer the unit of product from the shipper to the receiver. Thus the captive pallet is kept or “captured” for reuse at the point of shipment. 
     At the receiving point, the product is pulled from the trailer using a push-pull attachment or a regular fork-lift truck and placed on the purchaser&#39;s captive pallet. From that point, it is handled as a normal palletized load using a regular forklift and normal warehouse storage techniques. The shipping/receiving cycle is described in greater detail later in this application. 
     Both the producer and his customer keep their good quality wood, metal or plastic pallet in-house. The issue of who destroyed or damaged a $50-$200 plastic pallet, who pays for a lost pallets, cost of returning empty pallets and all the associated problems of using inferior quality wood pallets and wood pallets in general are eliminated. 
     The slip sheet utilized by the present invention is a product which utilizes and creates a market for virgin and/or recycled and/or off- specification polymeric material. The design of the slip sheet corrects the inherent problems of current plastic and fiber slip sheets. To teach the scope of these problems, later herein is a short synopsis of the problems associated with prior known slip sheets. 
     The disclosed slip sheet allows the material handling industry to adopt it as a shipping medium, currently performed by pallets. The design this slip sheet eliminates the need for a forklift attachment called a push-pull at the shipping location for many products. 
     The purpose of this invention is to eliminate the need for a push-pull attachment at the receiving end after product has been shipped using the disclosed slip sheet. 
     There are two major obstacles associated with current slip sheets. One obstacle is the occurrence of inaccessibility of the lip/tab due to crumpling during transit or shifting of the load. The other obstacle is maintenance of the product on the slip sheet in transit. 
     Additionally, there are related issues with current slip sheets. Product damage and/or spillage caused by the push-pull gripper jaws colliding with the packaged unit in the operators attempt to grasp the deficient lip/tab. Product damage and/or spillage caused by the push-pull gripper jaws colliding with the packaged unit during the push-pull&#39;s jaw release and push cycle. Further, cost considerations need to be made because of the need to have a push-pull at both the shipping and receiving points to handle the current slip sheets. Also, the increasing cost of more sophisticated designed push-pull in an attempt to overcome the inadequacy of current slip sheets lip/tab and their resultant cost as a high maintenance item must be considered. 
     Field interviews verify that slip sheet and push-pulls in general, do not work well and exhibit these shortcomings, preventing slip sheets from enjoying a greater share of the material handling market. 
     One material handling area that slip sheets have made an impact is in the grocery industry. However it is one thing to shift a few hundred pound palletized unit of potatoes chips or corn flakes back unto the slip sheet and another thing to restack 2500 pounds of 40 or 80 pounds bags of salt that has shifted in transit. It should be noted that with present slip sheet design, it is only necessary that the product shift as little as ⅛ inch and the lip/tab crease will be covered pushing the lip/tab tightly against the floor of the trailer/container/railcar. With certain bagged products, simply settling during transit will cause the footprint of the product to expand covering the creased area, causing it to be pushed tightly against the floor. Obviously, this creates a problem at the receiving end as it is impossible to grasp the tab/lip and the jaws and platens of the push-pull slide over the top of the product, resulting in product damage. It then become incumbent upon the receiver to unload the unit by hand with manual labor called “humping”. 
     The technique to make the slanted lip disclosed within U.S. Pat. No. 5,881,651, was added to further enhance and ensure the ability of the lip/tab to fold-up and not crumple when units are added in-line. It was this concept that assured good presentation of the lip/tab for the push-pull&#39;s jaws to clamp and/or make an accentuated angle so an operator could simply drop the lift trucks push-pull&#39;s platens and/or forks and slip under the slip sheet. 
     By having a compressible convex airfoil-type cross-sectional area to facilitate the grasping of this type lip/tab in conjunction with the front sidewall, several of the needs of a slip sheet were met. Obviously, it was discovered this design also allowed us to employ a conventional lift truck with tapered forks, meeting several of the additional needs of the material handling industry. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, there is disclosed a new and improved captive pallet and slip sheet combination which overcomes the problems associated with both a wood pallets transport system and a captive pallet transport system. 
     Further in accordance with the invention, the slip sheet of the present invention is formed from a flat sheet of material having a flat load receiving portion and four side edges. It is within the scope of the present invention to provide a slip sheet of the type disclosed in U.S. Pat. No. 5,881,651. However, it is further within the scope of the present invention to provide a slip sheet having conventional tabs, or having no tabs. Slip sheets having other designs may require the receiver to use push/pull attachments on forklifts. 
     Further in accordance with the invention, the captive pallet of the present invention comprises a first fork receiving area for reception of the forks of a conventional forklift for use when the captive pallet is moved, whether in a loaded or unloaded state. The captive pallet also provides a second fork receiving area for reception of the forks of a conventional forklift when it is desired to move only the load, either to load onto the captive pallet or remove from the captive pallet. Various embodiments of captive pallets are provided in the present invention, all having the common feature of providing first and second fork receiving areas. When the captive pallet is engaged on a ground surface in position for normal usage, the second fork receiving area is located higher from the ground surface than the first fork receiving area. The first fork receiving area is characterized by the presence of at least one upper barrier member against which the forks abut when the captive pallet is raised off the ground by the action of the associated forklift. The second fork receiving area is characterized by the absence of any upper barrier. The captive pallet further includes a plurality of planar load supporting surfaces adjacent the second fork receiving areas. 
     Further in accordance with the invention, there is provided a method of transporting materials. The method includes utilization of a captive pallet and slip sheet combination. A captive pallet having a first fork reception area adapted for use with the forks of an associated forklift. The captive pallet further includes a second fork reception area adapted for use with the forks of an associated forklift. An unloaded captive pallet may be properly positioned for reception of a load by placing the forks of an associated forklift into the first fork receiving area, raising the captive pallet from its resting position, transporting the captive pallet to a load receiving area, and lowering the captive pallet to the ground (or loading platform, etc). A slip sheet may then be positioned onto the load supporting surfaces. A load of material may be placed onto the load receiving portion of the slip sheet. The material may be secured to the slip sheet by any means known in the art such as binding, shrink wrapping and the like. The combination of loaded slip sheet and the captive pallet may be transported to another area by utilizing the associated forklift and the first fork receiving areas as discussed above. In order to move only the loaded slip sheet, the forks of the associated forklift are inserted into the second fork receiving areas. Upward movement of the forks cause the forks to abut the underside of the slip sheet and lift it off the captive pallet. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may take physical form in certain parts and arrangement of parts. A preferred embodiment of these parts will be described in detail in the specification and illustrated in the accompanying drawings, which form a part of this disclosure and wherein: 
         FIG. 1  is a side view of a push-pull type truck&#39;s forks and push-pull apparatus; 
         FIG. 2  is a front view of a push-pull type truck&#39;s forks and push-pull apparatus; 
         FIG. 3  is a perspective view of a captive pallet disclosed herein; 
         FIG. 4  is a side view of the captive pallet of  FIG. 3 ; 
         FIG. 5  is a front view of the captive pallet of  FIG. 3 ; 
         FIG. 6  is a perspective view of an inverted captive pallet; 
         FIG. 7  shows the nesting of the inverted captive pallets; 
         FIG. 8  is a perspective view of a slip sheet; 
         FIG. 9  is a perspective view of a slip sheet of the invention described herein; 
         FIG. 10  is an enlarged side view showing the compressible tab of the slip tray of  FIG. 9 . 
         FIG. 11  is an exploded view of a captive pallet/slip sheet combination of the present invention; 
         FIG. 12  is a perspective view of a further embodiment of a captive pallet; 
         FIG. 13  is an exploded view of another embodiment of a captive pallet/slip sheet combination according to the invention; and, 
         FIG. 14  is a perspective view of yet another embodiment of a captive pallet. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Push-pulls were originally designed over forty years ago to be used with cardboard and fiberboard slip sheets. The ambition for the slip sheet was to replace a wood pallet and/or pallets in general as the instrument which move products from a shipping location to a receiving location. 
     Referring now to the drawings, which are for purposes of illustrating a preferred embodiment of the invention only, and not for purposes of limiting the invention,  FIGS. 1 and 2  show a push-pull  10  having two forks  12  which have an extreme taper at the end. These forks are also known within the industry as platens. The platens  12  support the weight of the material as it is pulled from the captive pallet. 
     The push-pull hydraulics extend the attachment jaw  14  to grip a lip/tab  22  (best shown in  FIG. 8 ) which extends beyond the footprint or surface loading area  24  of the slip sheet  20 . As the push-pull gripper jaws  14  close, the hydraulic extension  16  retracts and pulls the load that is packaged on the slip sheet  20  from the captive pallet onto the platens  12 . The load is taken to the loading dock and the push-pull hydraulic extension  16  pushes the load into the conveyance vehicle. Next, the hydraulic extension  16  opens the gripper jaws  14  and hydraulically pushes the load from the platens  12  simultaneously as the lift truck backs away from under the load. Thus, the load is deposited on the floor of the trailer or double-stacked onto a similar load. 
     At the receiving end, the purchaser/receiver, using a push-pull  10  grips the edge of the slip sheet  20 , pulling it onto the platens  12 , carries it to a captive pallet and pushes the load onto a waiting captive pallet. From that point, the material is handled in-house in the same manner as if it had been originally shipped on a conventional wood, plastic, or metal pallet. 
     In another embodiment, a captive pallet may not be used, and the slip sheet  20  will serve as the support base while the material is stored in-house. 
       FIGS. 3-5  depict a preferred embodiment of the invention herein. A captive pallet  30  is shown having a front  32 , a rear  34  and sides  36 ,  38 . The front  32  and rear  34  of the captive pallet  30  are both able to receive the forks  12  of a fork-lift type truck. The captive pallet  30  shown is preferably rectangular in configuration but also could be square or other shapes and still be within the scope of this invention. 
     The captive pallet  30  comprises a top  40  and bottom  42  both of which have a centerline  41 ,  43 . The centerlines  41 ,  43  are taken from the width W of the captive pallet  30 . In its preferred embodiment, the center line  41  of the top  40  and the centerline  43  of the bottom  42  lie along the same vertical plane and in-line with one another. This creates vertical plane  44  formed by centerline  41  of the top  40  and centerline  43  of the bottom  42 . 
     The top  40  comprises a plurality of members  50  that preferably have an inverted u-shape. The inverted u-shaped members  50  are preferably spaced apart according to the width W of the captive pallet  30  and preferably comprise four (4) rows and four (4) columns. The columns C extend from the front  32  to the rear  34  of the captive pallet  30 . The rows R extend from the side  36  to the other side  38  of the captive pallet  30 . Therefore, in its most preferred embodiment, the captive pallet  30  comprises sixteen (16) inverted u-shaped members  50 . However, alternative arrangements and either eliminating the rows R or columns C are within the scope of this invention. 
     The inverted unshaped members  50  each have a length L M  and a width W M . Preferably, the overall width W is 45 inches (114.3 cm) and the column W C  is preferably 6.5 inches (16.51 cm). Therefore, the width of the members W M  is 6.25 inches (15.875 cm) and 6.5 inches. The members  50  nearest the sides  36 ,  38  are typically 6.25 inches in width, while the two center members are typically 6.5 inches. However, the width W of the captive pallet  30  can vary as well as the width W M  of the members, as well as the column width W C . 
     The preferred embodiment of the inverted u-shaped members  50  are disclosed as having a hollow portion  52  thus creating the u-shape. However, the hollow portion  52  can be eliminated thus leaving the member  50  as solid. Again, in its most preferred embodiment, the center columns  54  of the members  50  have a centerline  56  such that they lie along the same line and in the same plane of their respective later-described dividers  70 . The overall preferred embodiment is such that there is equal distribution of weight over the center  31  of the captive pallet  30 . This is accomplished by having the center columns  54  in their most preferred embodiment, as described above. 
     Dividers  70  are mounted between the top  40  and bottom  42  of the captive pallet  30 . The dividers  70  join the top  40  and bottom  42  of the captive pallet  30 . The dividers  70  extend from the pallet front  32  and terminate at the pallet rear  34 . The dividers  70  aid in support of the material the captive pallet  30  is supporting. Further, the dividers  70  create the later-described slots  80 . The dividers  70  are preferably rectangular in shape. The dividers  70  are located such that their centerline  72 , which runs from the pallet front  32  to the pallet rear  34 , is parallel with the sides  36 ,  38  of the captive pallet  30 . However, having the centerline  72  of the dividers  70  can also be situated such that their centerline is not parallel to the sides  36 ,  38 . However, having the centerlines  56  situated such that they are parallel with the sides  36 ,  38  allows for the forks  12  to enter within the later-described slots  80  and not be interfered by, or with the dividers  70 . The dividers  70  must have a height H great enough to allow the forks to enter between the top  40  and bottom  42  of the captive pallet  30 . Additionally, the height H must be such that it allows the forks  12  to enter the captive pallet  30  easily and without having to be extremely precise. Preferably, the dividers  70  comprise sixteen (16) equally spaced in rows and columns. 
     Slots  80  are formed by the top  40 , bottom  42  and the dividers  70 . The slots  80  are located along the front  32  and rear  34  of the captive pallet  30 . In its preferred embodiment, one of the slots  80  is located within the center of the captive pallet  30  such that it shares the same vertical centerline as that of the top  40  and bottom  42  of the captive pallet  30 . Or put another way, the centerline  84  of the center slot  82  is in-line with the centerlines  41 ,  43 . Preferably, the captive pallet  30  comprises three (3) slots thereby equalizing the captive pallet  30 . 
     With reference to  FIGS. 6 and 7 , an alternative embodiment of the present invention is disclosed. An inverted captive pallet  90  is shown having a front  92 , rear  94 , sides  96 ,  98 , top  100  and base  102 . A plurality of first channels  104 ,  106 ,  108 , form the base  102 . A plurality of second channels  110 ,  112 ,  114 ,  116  form the top  100 . The first channels  104 ,  106 ,  108  have a width, centerline and extend from the pallet front  92  to the pallet rear  94 . The first channels  104 ,  106 ,  108  accept the forks  12  of the truck. Preferably, the first and second channels are rectangular. 
     The second channels  110 ,  116  have a length, width and centerline and are mounted to the first channels  104 ,  108 . The centerline  118  of the first channels are perpendicular to the centerlines  120  of the second channels. The second channels  110  can also form, by themselves, the sides  96 ,  98  of the inverted captive pallet  90 . The second channels preferably have a plurality of u-shaped openings  122 . The u-shaped openings  122  allow for the insertion of a securing means  130  to underlie a load placed upon the inverted captive pallet  90 . The securing means  130  is typically some sort of a strap, belt or other means to secure the load placed upon the inverted captive pallet  90 . 
     In its preferred embodiment, the inverted captive pallet  90  comprises three (3) first channels  104 ,  106 ,  108  and the second channels  110 ,  112 ,  114 ,  116  comprise four (4) each having three (3) u-shaped openings  122 . Each u-shaped opening  122  has a centerline that corresponds with the centerline  120  of the  118  first channels  104   106 ,  108 . Put another way, each u-shaped opening  122  is located directly above the first channels  104   106 ,  108  such that the centerline of the u-shaped opening and the centerline of the first channel lie along the same vertical plane. Preferably, the ushaped openings each have a width Wo 3.5-8.0 inches, inclusive. Again, in the preferred embodiment, the width Wo of the openings  122  are greater than the width of the first channels  104 ,  106 ,  108 . As shown within  FIG. 7 , this allows for proper stacking of the captive pallets  90  upon themselves. The first channels  104 ,  106 ,  108  fit within each of the openings  122 , which also allow for proper removal by a fork-lift type truck. 
     The slip sheet  130  of the present invention has upstanding walls  132 ,  133 ,  134 ,  135 , as well as grasping tab  136 . Folded portions  137 ,  138 ,  139  and  140  are registered and affixed to the walls within slotted portions  141  as shown. The advantage of the grasping tab  136  from those known in the prior art is the cross-section which has one offset crease to allow for a “spring” action of an elliptical lip  144 . This serves to keep an elliptical lip  144  off of the supporting surface. Additionally, this keeps the elliptical lip  144  from being compressed and/or crushed from material set on top and/or pushed up against its opposite lip  144 . This is accomplished by the off-set crease wherein the length L 144  of the elliptical lip  144  exceeds the length L 142  of the lip  142 . The length L 144  is measured as its perimeter, thus yielding the length L 144 . Thus, the tab  136  has two (2) lips, an elliptical lip  144  having a radius of curvature R, and lip  142  being relatively flat, or having multiple creases to allow for ridged off-set lips, i.e., fiber board. This elliptical lip  144  permits the grasping fingers on a push-pull type lift truck to obtain a better grip. 
     A method of transporting materials utilizes a slip sheet and captive pallet combination. The slip sheet is typically upon the captive pallet whereby the material to be transported is within the slip sheet. The method comprises placing the material to be transported within the slip sheet from a shipping location. The material within the slip sheet is preferably secured by the above-mentioned securing means. The slip sheet and its material are then removed from the captive pallet by a push-pull or fork-lift type truck. The push-pull type truck typically utilizes its features to grasp the tab portion  136  of the slip sheet  130  to pull the slip sheet from the captive pallet. The captive pallet does not leave the shipping location and it used for incoming slip sheets. 
     The slip sheet, along with the material contained therein, is placed within a movable carrier such as a tractor-trailer type truck, or other means, and shipped to its receiving location. At the receiving location, the slip sheet is removed from the movable carrier by use of a push-pull or fork-lift type truck similar to the manner described above. The slip sheet is then placed upon a pallet, or captive pallet. 
     The present invention, is further directed to a new and improved captive pallet and slip sheet combination  150  as shown in  FIG. 11 . The slip sheet  154  is formed from a flat sheet of material having a flat load receiving portion  158  and four side edges  160 . It is within the scope of the present invention to provide a slip sheet of the type disclosed in U.S. Pat. No. 5,881,651. However, it is further within the scope of the present invention to provide a slip sheet having conventional tabs, or having no tabs. Slip sheets having these other designs may require the receiver to use push/pull attachments on forklifts. 
     The captive pallet  164  comprises a first fork receiving area  166  for reception of the forks of a conventional forklift (not shown) for use when the captive pallet  166  is moved, whether in a loaded or unloaded state. The captive pallet  164  also provides a second fork receiving area  170  for reception of the forks of a conventional forklift when it is desired to move the slip sheet  154  with or without a load  174  (shown in phantom lines), either to place it upon the captive pallet  164  or remove it from the captive pallet  164 . Various embodiments of captive pallets  164 A- 164 C are shown in  FIGS. 12-14 , all having the common feature of providing first and second fork receiving areas  166 ,  170 . When the captive pallet  164  is engaged on a ground surface in position for normal usage, the second fork receiving area  170  is located higher from the ground surface than the first fork receiving area  164 . The first fork receiving area  164  is characterized by the presence of at least one upper barrier member  176  against which the forks abut when the captive pallet  164  is raised off the ground by the action of the associated forklift. The second fork receiving area  170  is characterized by the absence of any upper barrier. The captive pallet  164  further includes a plurality of planar load supporting surfaces  180  adjacent the second fork receiving areas  170 . 
     With reference to  FIG. 11 , a method of transporting materials includes utilization of a captive pallet  164  and slip sheet  154  combination. A captive pallet  164  having a first fork reception area  166  adapted for use with the forks of an associated forklift (not shown). The captive pallet  164  further includes a second fork reception area  170  adapted for use with the forks of an associated forklift. An unloaded captive pallet  164  may be properly positioned for reception of a load by placing the forks of an associated forklift into the first fork receiving area  166 , raising the captive pallet  164  from its resting position, transporting the captive pallet  164  to a load receiving area, and lowering the captive pallet  164  to the ground (or loading platform, etc). A slip sheet  150  may then be positioned onto the load supporting surfaces  180 . A load  174  of material may be placed onto the load receiving portion  158  of the slip sheet  154 . The load  174  may be secured to the slip sheet by any means known in the art such as binding, shrink wrapping and the like. The combination of loaded slip sheet  154  and the captive pallet  164  may be transported to another area by utilizing the associated forklift and the first fork receiving areas  166  as discussed above. In order to move only the loaded slip sheet  154 , the forks of the associated forklift are inserted into the second fork receiving areas  170 . Upward movement of the forks cause the forks to abut the underside of the slip sheet  154  and lift it off the captive pallet  164 . 
     The invention has been described with reference to the preferred embodiment. Obviously, modifications and alterations will occur to others upon a reading and understanding of the specification. It is intended by applicant to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.