Abstract:
A slip sheet pallet comprising a first sheet engageable with a stacked array which is to be supported; a second sheet attached to the first sheet; at least one flap connected to and extending outwardly from at least one of the first and second sheets and gripable by a lift truck gripping assembly; at least one of the first and second sheets comprising a compound sheet with a plurality of distinct connected layers.

Description:
RECREANCE TO COP ENDING PROVISIONAL APPLICATION  
       [0001]    The benefit of earlier filed co-pending U.S. Provisional Patent Application Serial No. 60/186,411 filed Mar. 2, 2000 for SLIP SHEET, Attorney Docket No. CBC 2000-2PRV, which is hereby incorporated by reference for all that it discloses, is hereby claimed. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    This invention relates to pallets and slip sheets, and more particularly to an improved slip sheet.  
           [0003]    Material handling apparatus for industrial use is commonly designed for ease of storage and handling in a warehouse and shipping on truck or rail. Different kinds of containers for various types of goods, for example cases of beer, are commonly arranged in a generally cubical array and are supported on a pallet. The array and pallet may then be lifted by a lift truck and stacked upon another array of containers for conservation of storage space. The array and pallet may also be conveniently loaded and unloaded for shipping in trucks, railcars, ships and other transport means.  
           [0004]    Commonly used pallets are constructed from wood with two planar support surfaces separated by spaced rails. The support surfaces have the general size and shape of the array to be supported, and the pallet is about 5 {fraction (1/2 )}inches thick. The pallet and array of containers are lifted and moved by inserting the forks of a forklift between the vertically separated support surfaces and the horizontally spaced spacer rails. Wood pallets are relatively expensive. Furthermore, the thickness of these pallets takes up useful storage space and their weight adds to transportation expense.  
           [0005]    These problems have been somewhat overcome by the development of slip sheets, also referred to as slip sheet pallets or slip pallets. A typical slip sheet comprises a relatively thin sheet of a material, such as chipboard or plastic, for supporting the array of containers. The array and slip sheet are lifted by gripping a lip portion extending from an edge of the slip sheet and holding it under tension with a lift truck gripping mechanism while slipping a platen (a spatula like member) of the lift truck under the slip sheet. The platen is raised to lift the array and slip sheet and the lift truck then moves them to a desired location where the slip sheet and the array are pushed off of the platen. Although slip sheets offer various advantages over common wooden pallets, some problems have been found in their use. Unlike conventional wood pallets, slip sheets do not have a lower opening for insertion of a lift truck lifting platform. Sliding a platen under a slip sheet resting on a hard surface causes a deformation wave to pass through the slip sheet as the leading edge of the platen moves below it. One significant problem with simple slip sheets formed from a single layer of plastic or chip board has been that shock, vibration and deformation waves, encountered during lift truck handling or rail or truck transportation are transmitted through the slip sheet to the array causing damage to items in the array, particularly items stacked at the bottom of the array. For example bottom tier beverage cans are often damaged by such shocks or deformations. Attempts to provide slip sheets having cushioning and stiffening capabilities to resist such shocks and deformation waves have heretofore met with only limited success. In some cases the shock absorption capabilities have been too meager. In others the cost of producing such shock absorbing slip sheets has been too great and/or the size and/or weight of the shock absorbing slip sheet has been commercially unacceptable. Also, where shock absorption is achieved by making the slip sheet extremely flexible, damage caused by deformation waves has been exacerbated.  
           [0006]    Some of the various types of pallets and slip sheets which have been employed in the past are disclosed in: U.S. Pat. No. 3,199,468 issued Aug. 10, 1965 for NESTABLE PALLETS of Sullivan; U.S. Pat. No. 3,545,249 issued Dec. 8, 1970 for DIMPLE AND METHOD OF FORMING SAME of Brown; U.S. Pat. No. 3,776,145 issued Dec. 4, 1973 for SLIP PALLET of Anderson, et al; U.S. Pat. No. 3,850,116 issued Nov. 26, 1974 for SLIP PALLET REINFORCED WITH FILLERS of Mackes; U.S. Pat. No. 4,042,127 issued Aug. 16, 1977 for SLIP PALLET AND DIVIDER SHEET of Brossia; U.S. Pat. No. 4,507,348 issued Mar. 26, 1985 for CORRUGATED BOARD-LIKE SHEET MADE OF SYNTHETIC RESIN of Nagata, et al; U.S. Pat. No. 4,562,718 issued Jan. 7, 1986 for PALLET AND METHOD OF PRODUCTION of Dunk; U.S. Pat. No. 4,906,510 issued Mar. 6, 1990 for METHOD AND APPARATUS FOR FORMING A HINGE FOR LAMINATED CORRUGATED MATERIAL of Todor, Jr., et a/.; U.S. Pat. No. 5,226,372 issued Jul. 13, 1993 for SLIP PALLET WITH A CUSHIONING EFFECT of Frenkel, et al.; and German Patent No. 2625346 filed Jun. 4, 1976 for FLEXIBLE COMPONENT of Stangeland, et a/. The above patents are each hereby specifically incorporated by reference for all that is disclosed therein.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention is directed to a slip sheet having substantial shock absorbing and deformation resisting capabilities and which is relatively durable, compact, light weight and inexpensive. The slip sheet is particularly adapted for use with stacked arrays of beverage containers. In one preferred embodiment, the slip sheet comprises plural sheets at least one of which is a composite sheet which may be a honeycomb sheet or fluted sheet or standing rib sheet constructed from paper or plastic which provides shock absorption and deformation reduction. 
       
    
    
     BRIEF DESCRIPTION THE DRAWING  
       [0008]    [0008]FIG. 1 is a top plan view of a slip sheet pallet;  
         [0009]    [0009]FIG. 2 is a cross sectional elevation view of a slip sheet pallet;  
         [0010]    [0010]FIG. 3 is another more detailed cross sectional elevation view of a slip sheet pallet wherein the thickness of some of the layers has been exaggerated for illustrative purposes;  
         [0011]    [0011]FIG. 4 is a top plan view of another embodiment of a slip sheet pallet;  
         [0012]    [0012]FIG. 5 is a front elevation view of the slip sheet pallet of FIG. 4;  
         [0013]    [0013]FIG. 6 is a top plan view of a top sheet portion of the slip sheet pallet of FIG. 4;  
         [0014]    [0014]FIG. 7 is a front elevation view of the top sheet portion of the slip sheet pallet of FIG. 4;  
         [0015]    [0015]FIG. 8 is a top plan view of a bottom sheet portion of the slip sheet pallet of FIG. 4; and  
         [0016]    [0016]FIG. 9 is a front elevation view of the bottom sheet portion of the slip sheet pallet of FIG. 4. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]    [0017]FIGS. 1 and 2 illustrate a slip sheet or slip pallet or ship sheet pallet  10  having a generally parallelepiped shaped body  12  (i.e., a rectangular box shaped body). At least one, and preferably a plurality of peripheral flaps  14 ,  16 ,  18  extend outwardly from the body  12 . The body  12  includes a top sheet  20 , a base sheet  80 , and an intermediate sheet  110 .  
         [0018]    Top sheet  20 , as best illustrated in FIGS. 2 and 3, includes a top surface  24  and a bottom surface  26 . The top sheet  20  terminates at lateral edge surfaces  21 ,  23 ,  25 ,  27 , which may be planar vertical surfaces. Edge surfaces  21  and  25  are in one embodiment, parallel, and arranged perpendicular to parallel edge surfaces  23  and  27 . In one embodiment the top sheet  20  is a double walled corrugated sheet including, as shown in FIG. 3, a top wall paper layer  32  a bottom wall paper layer  36  and an intermediately disposed serpentine (fluted) paper layer  42 . The three paper layers  32 ,  36 ,  42  are preferably coextensive.  
         [0019]    The top wall  32  has an upper surface  34  and a lower surface  35 . The bottom wall  36  has an upper surface  38  and a lower surface  40 . The intermediately disposed fluted member  42  has an upper surface  44  and a lower surface  46 . The intermediate member comprises a plurality of longitudinally extending flutes  48 ,  50 ,  52  defined by a series of flute crests  54  and troughs  56 . The upper surface  44  of crests  54  are adhered as by a water based glue layer  55  to the lower surface  35  of top wall  32 . The lower surface  46  of the troughs  56  are adhered as by a glue layer  57  to the upper surface  38  of bottom wall  36 .  
         [0020]    A moisture barrier layer  60  may be applied to the top wall  32  to prevent moisture penetration into the top sheet  20 . The moisture barrier may be a layer of spray coated material or alternatively may be a layer applied as a hot melt or may comprise a plastic film material which is adhered to the upper surface  34  of paper layer  32  by a suitable adhesive. As another alternative, the top wall  32  may be impregnated with a moisture barrier to prevent moisture penetration therethrough by known commercial processes such as rod or gravure application. Commercially available coating material includes repulpable moisture vapor barriers such as Vapor Coat and X300, both manufactured by Michelman, Inc., 9080 Shell Road, Cincinnati, Ohio 45236; or V-647 Pro Shield Release Coating manufactured by Progressive Coatings, 455, West 61 st  Street, Shreveport, La. 71106. A typical coating thickness is 3 wet lbs. Per 1,000 square feet of surface area.  
         [0021]    Top sheet  20  preferably has a thickness of between 0.0468 inches and 0.1406 inches and more preferably between 0.0625 inches and 0.09375 inches.  
         [0022]    Commercially available materials suitable for forming the top sheet  20  include industry standard single-walled, B-flute corrugated sheet such as single-walled or double walled container board sold by International Paper having a business address of 6400 Poplar Avenue, Memphis, Tenn. 38197.  
         [0023]    Base sheet  80 , as best illustrated by FIG. 3, comprises a top surface  82  and a bottom surface  84 . Base sheet  80  may have a fiberboard layer  86  which may be formed from fiberboard having a thickness of preferably between .085 inches and .120 inches and most preferably between .090 inches and .10 inches. The fiberboard layer has a top surface  88  and a bottom surface  90 . The bottom surface  90  is coated with a moisture barrier layer  92  which may be similar or identical to the moisture barrier layer  60  described above for the top sheet  20 . Commercially available fiberboard suitable for use in base sheet  80  include fiberboard sold by Gaylord Container Corp. having a business address of 186 Bayline Circle, Folsome, Calif. 95630.  
         [0024]    Intermediate sheet  110  comprises a top surface  112 , a bottom surface  114 , and four lateral side faces  111 ,  113 , etc. (only two shown) arranged below and parallel to lateral edge surfaces  21 ,  23 ,  25 , and  27 , respectively, of top sheet  20 . Intermediate sheet  110  may comprise a honeycomb layer  118  and top and bottom layers  1   17 ,  119 . The top and bottom layers are adhered to top and bottom surfaces  121 ,  123  of honeycomb layer  118  by adhesive such as water base glue layers  125 ,  127 . The honeycomb portion  118 , as shown in FIG. 1, comprises a plurality of hexagonal cross sectioned cells  120 ,  122 ,  124 ,  126 , etc. Each of the cells of the honeycomb has six vertically extending side walls  128 . The cells may be  1  inch in height and may have a maximum cross section dimension of about ⅜ inch. (Many other widths ranging up to 3 or 4 inches may also be acceptable depending upon strength, elasticity, etc.) The honeycomb may be manufactured from 26 lb. kraft paper. The top and base layers  117 ,  119  may be 42 lb. kraft paper. A moisture barrier  130  is applied to the exposed sidewall of intermediate sheet  110  and may also be applied to the top sheet sidewalls  21 ,  23 ,  25 ,  27  as well. The moisture barrier  130  may comprise any suitable water resistant coating such as for example Michelman Vapor Coat manufactured by Michelman, Inc. having a business address of 9080 Shell Road, Cincinnati, Ohio 45236. Another suitable material is: V-647 Pro Shield Release Coating, manufactured by Progressive Coatings having a business address of 455 West 61 st  Street, Shreveport, La. 71106.  
         [0025]    As best shown by FIG. 2 flaps  14 ,  16 ,  18  may be provided through extension of base sheet  80 . The flaps ordinarily are tilted upwardly at an angle u of about 30 degrees as a result of a crease  132 ,  134 ,  136 , provided along the length of each flap. Each flap may have a linear outer terminal portion  140 , FIG. 1, position parallel to the adjacent lateral sides  111 ,  113 , etc. of the intermediate layer. Each flap also comprises opposite linear, tapering edge portions  142 ,  144  which in one preferred embodiment are sloped at an angle v of about 45 degrees from edge  140 .  
         [0026]    In one preferred embodiment of the invention the slip sheet  10  is adapted to receive a total of 120 cases (24 beverage cans or bottles per case) stacked 10 tiers high, 12 cases per tier and having a total weight of approximately 2,800 pounds. In a warehouse the loaded slip sheets are often stacked four high and thus the bottom slip sheet must support 4×2,800 lbs.=11,200 lbs. Each case has a rectangular shape with a base measuring 15-¾ inches by 10-⅜ inches. In this preferred embodiment the dimensions of the slip sheet, with reference to FIG. 1, may be as follows: a=53.50 inches; b=46.00 inches; c=3.75 inches; d=43.50 inches; e=39.75 inches; f=3.75 inches; g=a radius of 1.0 inch for an outwardly facing concave surface; and h=1.125 inches maximum. (Other case configurations, such as  18  container cases may of course be supported on similar pallets with suitable modification to accommodate the different case size.) The co-efficient of friction on the top surface  24  is preferably between about 0.30 and about 0.50 and is most preferably between about 0.35 and about 0.45. The co-efficient of friction on the bottom surface  84  is preferably between about .30 and about .50 and is most preferably between about .35 and about .45.  
         [0027]    Although one preferred construction for top sheet  20  has been described above in detail, various alternatives to that construction may also be employed including: multi-ply corrugated paperboard; single layer paperboard; multilayered, uncorrugated paperboard; plywood; particle-board;chip board; cork; fiberglass; plastic; rubber; natural or synthetic fabric which may be woven or unwoven; metal plate; or composites of any of the above described materials or other materials. Similarly, the same type alternatives as discussed immediately above could be used for the bottom sheet  80 .  
         [0028]    An integral flap formed from the bottom layer  80  was described with reference to the preferred embodiment of FIGS. 1 and 2; however, various alternatives to that flap construction may also be used. For example, integral flaps could be provided by extending and laminating a portion of the top layer to an extension of the bottom layer. Another alternative would be to extend both top intermediate and bottom layers and then to crush/compress the intermediate layer between the top and bottom layers while fixing the top layer relative to the bottom layer as by rivet devices or the like. Other alternative composite flap configurations formed from top and bottom layers are described in U.S. Pat. Nos. 4,906,510 and 4,507,348 which are hereby incorporated by reference for all that is disclosed therein. As a further alternative the flaps may be provided in a non-integral configuration from material identical to or different from the material used in the body  12  of the slip sheet  10 . Such flaps may be configured geometrically the same as those described above with reference to FIGS. 1 and 2 but may be attached to the body  12  by hinges which may be formed from the fabric or high strength paper or other high strength flexible material which is adhered to both the body  12  and each flap at various points along the length of the flap, either at the top surface of the flap or the bottom surface of the flap or at both top and bottom surfaces. In such a configuration the top hinge material may be used to hold the flap in an upwardly inclined position such as illustrated in FIG. 2 to maintain an angle u of approximately 30 degrees. The flaps may also be glued on flaps.  
         [0029]    The intermediate sheet  110  provides most of the shock absorbing and deformation resisting capability of the slip sheet  10  through its use of compressible, relatively elastic honeycomb material. The honeycomb material is preferably a paper material, but could in the alternative be formed from a number of different materials including rubber, foam rubber, plastic, plastic foam, or any other suitable material. Also, various geometric structures other than a honeycomb structure might be employed, for example, a parallelepiped shaped plate of plastic foam, multilayered corrugated board, gel, foam rubber, cork, or any of the various materials used for other shock absorbing purposes such as those used in the construction of athletic shoes. Other shapes such as egg carton shapes, or multiple truncated cone shapes, truncated pyramid shapes, dome shapes, cylinder shapes, standing rib shapes, etc. could be used. Also, rather than providing shock absorbing material in a sheet or plate, a bladder structure might be used, for example, an air bladder constructed from plastic or other suitable material and having either multiple, independent chambers or a single air chamber. Another alternative would be to provide an enclosure sealed at the top and bottom by the top and bottom sheets  117 ,  119  and sealed around the periphery by a suitable layer of plastic sealant or the like. This enclosure could be filled with various types of elastic, granular materials such as plastic foam or foam rubber peanuts or pebbles. Similarly, crushed paper or other types of shock absorbing “loose” material might be placed in such a cavity.  
         [0030]    While a multilayered slip sheet  10  having a compound top sheet  20 , a compound bottom sheet  80 , and a compound intermediate sheet  110  has been described above in the illustrated embodiment, it would also be possible to provide a slip sheet formed from one homogeneous material such as gel, cork, or plastic having a top layer and a bottom layer provided with appropriate moisture barrier material having a coefficient of friction in the ranges discussed above. The slip sheet  10  embodiment described above with reference to FIGS.  1 - 3  may be used to support 480 cases of beverage having a total weight of approximately 11,200 lbs., in a four slip sheet high, loaded stacking arrangement. This slip sheet is capable of significant shock absorption and yet weights only about 7-10 lbs. (as opposed to 40-90 lbs. For a typical wood pallet).  
         [0031]    The above described slip sheet  10  embodiment substantially meets the following loading and deflection specifications:  
         [0032]    a) Vertical load carrying requirements.  
         [0033]    i) Uniform load. The slip sheet shall support a two stack high uniform load of 5,600 pounds while being carried by a pull pack modified fork lift truck. The load shall be distributed on the top face of the slip.  
         [0034]    ii) Warehouse load. The slip sheet shall support a static load equivalent to four full beer pallets stacked vertically (11,200 pounds) upon a level concrete floor. Deflection of the honeycomb shall be less than or equal to ¼ inch. The deflection must be uniform across the slip sheet diagonal+⅛.  
         [0035]    iii) Concentrated load. The slip sheet shall support a single static concentrated load of 300 pounds distributed over an area 6 inch×6 inch placed at the corner of the slip sheet. Deflection of the slip sheet shall not exceed ¼ inch in the loaded area.  
         [0036]    iv) Racking load. The slip sheet shall be able to support 2800 pounds on a three rail rack with rails spaced at 22 inches. Rack rails shall be 2 inches wide and the full length of the slip sheet.  
         [0037]    b) Impact load requirements.  
         [0038]    i) Uniform load. The slip sheet must resist a uniformly distributed impact load while fully supported on a pull pack modified fork lift truck equivalent to 1.25 times the load described in (a)(i) above, in conformance with ASTM specification D1185. There shall be no permanent deformation or buckling of the honeycomb sheet.  
         [0039]    ii) Horizontal load. The slip sheet shall resist a load created by driving the fork lift at 10 mph and applying the brakes without release while supporting the load defined in (a)(i) above. The platen is to be tilted at 10- toward the truck. The slip sheet and load shall remain upright upon the platen and shall not shift more than 2 inches in the direction of travel. There shall be no permanent deformation or buckling of the honeycomb sheet.  
         [0040]    ii) Horizontal concentrated load. The slip sheet must be capable of distributing a lateral load of 300 pounds applied to the mid height of the top pallet during the stacking process. The bottom slip sheet shall incur no localized deformation and shall maintain the stacked beer pallets in a stable and vertical position.  
         [0041]    iv) Railcar and truck vibration loads. The slip sheet shall be capable of supporting a double stacked load, i.e., two loaded pallets while being submitted to ASTM testing methods D4169, Random Test Option, Assurance level II.  
         [0042]    The above slip sheet of FIGS.  1 - 3  achieves these loading and deflection requirements in a relatively compact, lightweight and inexpensive construction which is sufficiently durable to be used once from manufacturer to retail outlet, i.e., manufacturer warehouse handling, shipment to retail distributor and retail distributor warehouse handling. The slip sheet  10  may then be easily ground up and, depending upon the waterproof coatings used, recycled. Polypropylene for example, is readily recycled.  
         [0043]    Another embodiment of a slip sheet pallet  210  is illustrated in FIGS.  4 - 9 . Double slip sheet  210  comprises a single top sheet  212  and a single bottom sheet  214 .  
         [0044]    The top sheet  212  may be rectangular in shape with a top surface  220 , a bottom surface  222  and four lateral side edge surfaces  224 ,  226 ,  228 , and  230 .  
         [0045]    The bottom sheet  214  has a central body portion  240  which may be of the same general size and shape as the top sheet  212 . The bottom sheet also comprises at least one and preferably  3  flaps  242 ,  244 ,  246  integrally formed with the central body portion. The bottom sheet has a top surface  250 , a bottom surface  252  and side wall surfaces  254 ,  256 ,  258  located at the terminal edges of flaps  242 ,  244 ,  246 , respectively. Another side wall edge surface  260  is located at the side of the bottom sheet  214  which does not include a flap.  
         [0046]    The plan view dimensions of the slip sheet pallet  210  may be any dimensions which are commensurate with the size and shape of the object or objects to be loaded on the pallet. It may, for example, be the same or similar to that described above with reference to FIG. 1 for the loading arrangement described for that embodiment.  
         [0047]    The bottom sheet  214  may be a homogeneous, dimpled, single plastic layer sheet such as is currently used commercially as a stand alone slip sheet. It may be the same as the slip sheet described in detail in U.S. Pat. No. 5,226,372 issued Jul. 13, 1993 of Frenkel, et al. for Slip Sheet with cushioning Effect which is hereby incorporated by reference for all that it discloses. The bottom sheet  214  preferably comprises a single layer of plastic which in one preferred embodiment has a thickness of about 0.05 to 0.06 inches with downwardly projecting dimples  213 ,  215 , etc. evenly distributed across the central body portion  240  on about 1.0 inch centers. Each dimple may have a height of about 0.1 inch and a radius of about 0.25 inch.  
         [0048]    The top sheet  212  in one embodiment comprises a single honeycomb layer of paper material covered by top and bottom layers of paper material which are adhered to the honeycomb layer in the same manner as described above with respect to honeycomb layer  118 , top and bottom layers  117  and  119 , and glue layers  125 ,  127 . In one embodiment the cell size of the honeycomb layer is ½ inch, i.e. ½ inch between opposite side walls. The honeycomb may be constructed from craft paper such as 26 lb. to 32 lb. mullen verse paper having a cell wall thickness of 0.01 inches. The top and bottom layer paper may be the same as the cell wall paper or slightly thicker, e.g. 10% thicker then the cell wall paper. In one embodiment in which the cell height is ½ inch the stiffness per surface area of the top layer may be approximately 94,447 lbs./inch/sq. inch. In an embodiment in which the cell height is 1 inch the stiffness per surface area may be approximately 47,223 lbs./inch/sq. inch. In an embodiment in which the cell height is 2 inches the stiffness per surface area is approximately 23,611 lbs./inch/sq. inch.  
         [0049]    In another embodiment in which the cell size is ⅜ inch, i.e ⅜ inch between side wall faces of the cell and in which the materials and paper thickness etc. remain the same as in the above example. The stiffness per surface area for ½ inch height is 89,465 lbs./inch/ sq. inch; for 1 inch cell height is 44,732 lbs./inch/ sq. inch and for 2 inch height is 22,366 lbs./inch. sq. inch.  
         [0050]    In another embodiment of the top sheet  212  the top sheet comprises a standing rib polypropylene sheet having a construction similar to the double walled corrugated sheet illustrated in FIG. 3, including a top layer and a bottom layer. However the top and bottom layers are adhered to an intermediately disposed vertical (standing) rib layer (rather than a fluted layer). In one embodiment the top and bottom polypropylene sheets have a thickness of 0.03 inches and each rib  221 , 223  etc. in the ribbed layer has a thickness of 0.02 inches. The height of each rib  221 ,  223 , etc., may be 0.37 inches and the spacing between ribs may be 0.41 inches. This embodiment may have a stiffness per surface area of approximately 117,592 lbs./inch/sq. inch. An identical design except having a rib height of 0.29 inches may have a stiffness per surface area of approximately 150,031 lbs./inch/sq. inch. The lateral direction that the ribs extend may be the same direction as shown for the fluting in FIG. 1, or may be in a direction perpendicular to the direction shown in FIG. 1, i.e. parallel to edges  226 ,  230  and  132 ,  136 , as shown in FIG. 6, or may be in a direction diagonal to creases  132 ,  136 . One advantage of a plastic sheet, whether ribbed or honeycomb or other construction, over a similar paper sheet is moisture resistance.  
         [0051]    The double sheet slip sheet pallet  210  may have the top sheet  212  secured to the bottom sheet  214  by conventional adhesives, by sonic welding, stapling, riveting, or other attachment means. The top sheet  212  may also be secured to the bottom sheet  214  simply by friction. In this embodiment the top sheet  212  is simply laid on top of the bottom sheet  214  prior to loading the double slip sheet pallet  210 . The friction between surfaces when the slip sheet pallet is in a loaded state is sufficient to prevent lateral shifting between the two sheets  212 ,  214 . In such an embodiment the static coefficient of friction between the two sheets is preferably at least about 0.3 and is preferably about 0.4. One advantage of frictional or other easily disconnectable sheet attachment arrangement is that the more easily damaged top sheet  212  may be readily replaced after the slip sheet pallet  210  has been used, thus, saving the cost of replacing both sheet components of the compound slip sheet  210 .  
         [0052]    Cans located in the bottom case of a fully loaded pallet are subject to considerable shocks due to rail car and truck vibrations and to dynamic loads and defections associated with lift truck operation. The above described slip sheets of FIGS.  1 - 9  have been found to absorb sufficient shock and resist deformation sufficiently to significantly reduce bottom row damage to beverage cans.  
         [0053]    It is contemplated that the inventive concepts herein described may be variously otherwise embodied and it is intended that the invention is construed to include all such alternative embodiments except insofar as limited by the prior art.