Abstract:
A metal pallet ( 10 ) has a deck ( 12 ), a base ( 14 ) and a plurality of beams ( 16 ) therebetween. The deck ( 12 ), the base ( 14 ) and the beams ( 16 ) may be formed from lightweight sheet metal. The metal sheets are folded into the desired shape to respectively form the beams ( 16 ), and panels ( 18, 22 ) and slats ( 20, 32 ) for the deck ( 12 ) and the base ( 14 ). The panels ( 18, 22 ) and the slats ( 20, 32 ) are corrugated and the opposed side edges thereof may be folded upon themselves to provide for robust multi-ply edge constructions. Different types of corrugations may be provided over the panels ( 18, 22 ) and the slats ( 20, 32 ) to locally reinforce the pallet ( 10 ). The bottom portion of the beams ( 16 ) may be plastically deformed to create arched opening ( 58 ) to permit side entry of pallet handling equipment. The plastically deformed regions ( 60 ) of the beams ( 16 ) may be configured to improve the mechanical properties of the beam while providing maximal clearance for pallet handling equipment.

Description:
TECHNICAL FIELD 
     The application relates generally to material handling and, more particularly, to metal pallets, such as aluminum and galvanized steel pallets. 
     BACKGROUND OF THE ART 
     While most pallets are made of wood, some pallets are also made of plastic and metal. Each material has advantages and disadvantages relative to the others. 
     Presently, metal pallets represent less than 1% of the market. Metal pallets are generally costly compared to wooden pallets. Some metallic pallets are subject to oxidation, the use thereof for outside storage may thus be problematic. Also metal and plastic pallets typically offer less adherence for the stack of goods to be carried than wooden pallets, which may result in stability problems. Finally, conventional metal pallets are generally heavy. 
     Accordingly, there is a need for a new metallic pallet design. 
     SUMMARY 
     In accordance with a general aspect of the present invention, there is provided a metal pallet comprising a deck mounted on a plurality of laterally spaced-apart beams, at least peripheral ones of said beams having a one-piece sheet metal body including a pair of legs extending upwardly from a bottom end, the legs defining therebetween a hollow internal volume, the one-piece sheet metal having at least one die formed portion protruding into said hollow internal volume between longitudinally opposed ends of the one-piece sheet metal body, each of said at least one die formed portion defining an arched opening across the one-piece sheet metal body. 
     In accordance with another general aspect, there is provided a metal pallet comprising a deck, a base and a plurality of beams therebetween, each beam having a one-piece sheet metal body folded into a V-shaped elongated member including a pair of legs extending upwardly from a flat bottom end, the legs defining therebetween an internal volume, the flat bottom end having at at least one location therealong a plastically deformed portion die pressed into the internal volume between the legs of the one-piece sheet metal body so as to define a corresponding transversal arched opening between opposed longitudinal ends of the beam, the plastically deformed portion being fully accommodated within the internal volume. 
     In accordance with a further general aspect of the invention, there is provided a galvanized steel pallet has a deck, a base and a plurality of beams therebetween. The deck, the base and the beams are formed from lightweight galvanized steel sheet. The galvanized steel sheets are folded into the desired shape to respectively form the beams, and panels and slats for the deck and the base. The panels and the slats are corrugated and the opposed side edges thereof may be folded upon themselves to provide for robust multi-ply edge constructions. Different types of corrugations may be provided over the panels and the slats to locally reinforce the pallet. 
     Further details of these and other aspects of the present invention will be apparent from the detailed description and figures included below. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Reference is now made to the accompanying figures, in which: 
         FIG. 1  is a perspective top view of a galvanized steel palette in accordance with an embodiment of the present invention; 
         FIG. 2  is a perspective bottom view of the palette shown in  FIG. 1 ; 
         FIG. 3  is a side view of the palette shown in  FIG. 1 ; 
         FIG. 4  is an exploded view of the palette illustrating the panels, the beams and the slats forming the palette; 
         FIG. 5  is an enlarged side view of the palette illustrating details of the corrugation pattern of the top panels of the palette; 
         FIG. 6  is a bottom perspective view of a V-shaped beam forming part of the pallet; 
         FIG. 7  is a cross-section view of the V-shaped beam taken along line  7 - 7  in  FIG. 6 ; 
         FIG. 8  is a side elevation view of a stack of pallets, the pallets being nested one into each other; and 
         FIGS. 9 a -9 d    are sequential views schematically illustrating the sheet metal forming process used to form transversal arched openings in the beams. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  illustrates an example of a 48″×40″×5″ (1000 m×1200 mm×102 mm) weldless galvanized steel pallet  10 . The pallet  10  generally comprises a load supporting deck  12 , a base  14  and a set of beams  16  (three in the illustrated embodiment) interconnecting the deck  12  to the base  14 . The deck  12 , the base  14  and the beams  16  may all be made from galvanized steel sheets. According to one example, the components of the deck  12 , the base  14  and the beams  16  are made from a lightweight gauge of galvanized steel, such as lightweight gauges typically used in the ventilation industry. For instance, the components of the pallets could be made from standard 24 gauge galvanized steel sheets (ASTM 653B G90). It is understood that different gauges of steel could be used. For instance, any combination of 10 gauge galvanized steel sheet to 24 gauge galvanized steel to 24 gauge could be used. 
     Referring concurrently to  FIGS. 1 to 4 , it can be appreciated that the deck  12  of the pallet  10  may be composed of a front corrugated panel  18 , a central corrugated slat  20  and a rear corrugated panel  22 . It is understood that the number of panels and slats may vary. Referring more particularly to  FIG. 3 , it can be appreciated that slat  20  is narrower than the panels  18 ,  22 . For instance, the panels  18 ,  22  may have a width (W) equal to 500 mm whereas the slat  20  may have a width (w) of 100 mm. The slat  20  may be spaced-apart from the front and rear panels  18 ,  22  so as to define front and rear gaps  24  therewith. The central slat  20  and the panels  18 ,  22  are coterminous in the transversal direction of the pallet  10 . The corrugations of the panels  18 ,  22  and slat  18  extend transversally to the longitudinal axis of the pallet  10 . 
     In the embodiment illustrated in  FIGS. 1-4 , the panels  18 ,  22  and the central slat  20  are mounted on top of three laterally spaced-apart longitudinal beams  16 . In the illustrated embodiment, the beams  16  are identical. However, they could be different. According to the illustrated embodiment, all the beams  16  have a V-shaped open-top section with longitudinally extending lateral flanges  28  at the top. The deck panels  18 ,  22  and the central slat  20  may be riveted or otherwise suitably attached to the lateral flanges  28  of the beams  16 . The beams  16  may extend longitudinally the full extent of the pallet  10 . The bottom end of the beams  16  is flat to provide a suitable mounting surface  30  for the base  14 . 
     According to the illustrated example, the base  14  is composed of three corrugated bottom slats  32 . The bottom slats  32  are uniformly distributed along the length of the beams  16  and oriented transversally with respect thereto. The bottom slats  32  comprise a front bottom slat, a central bottom slat and a rear bottom slat. The front, central and rear bottom slats  32  may be identical and are coterminous to the deck panels  18 ,  22  and the deck central slats  20  in the transversal direction of the pallet  10 . According to the illustrated example, each bottom slat  32  has three pairs of laterally extending mounting flanges  34  distributed along the length thereof. The mounting flanges  34  of the bottom slats  32  may be riveted or otherwise suitably attached to the flat bottom end  30  of each beam  16 . 
     As best shown in  FIG. 5 , the front and rear panels  18 ,  22  of the deck  12  each have two different types of corrugations: central corrugations  38  and edge corrugations  40 . The central and the edge corrugations  38 ,  40  may have a trapezoidal shape and a same depth (e.g. 19 mm). However, the pitch of the corrugations  38  in the central area is greater than the pitch of the corrugations  40  in the lateral edge areas of the panels  18 ,  22 . For instance, the pitch of the central corrugations  38  may be twice that of the edge corrugations  40 . In accordance with one example, the pitch of the central corrugations  38  is 54 mm and the pitch of the edge corrugations  40  is 27 mm. The central corrugations  38  are designed to maximize the top bearing surface area of the pallet  10  while offering an adequate load bearing surface capability relative to the weight of the panel. According to one example, the central corrugations  38  have an 88 degrees opening angle. In contrast, the edge corrugations  40  may have a 26 degrees opening angle. The edge corrugations  40  have a smaller pitch and have almost vertical sides or legs extending between top and bottom webs, thereby providing for better mechanical properties with greater vertical load bearing capabilities at the lateral edges of the panels  18 ,  22 . 
     Multi-ply edges portions may be provided at the opposed lateral sides of the panels. For instance, a 3-ply edge portion  42  may be formed along the front edge of the front panel  18  by folding the front edge portion of the panel  18  twice upon itself. A 3-ply edge portion  44  may be similarly formed along the rear edge of the rear panel  22 . The folding of the edge portions of the panels  18 ,  22  at the front and the back of the pallet  10  eliminates the presence of sharp edges that would otherwise be present at the periphery of the pallet  10  and that could potentially be harmful for an operator when manually handling the pallet  10 . Furthermore, the multi-ply edge structures at the front and rear of the pallet  10  also act as front and rear bumpers to better resist potential lateral impacts of the forks of a forklift truck or other pallet handling equipment at the front and rear fork entries of the pallet  10 . 
     A 2-ply edge portion  46  may also be formed along the rear edge of the front panel  18  and along the front edge of the rear panel  22  adjacent to the central slat  20 . The 2-ply edge portions are formed by folding the edge portion of each panel upon itself. This also provides for smoother rounded edge at the top surface of the pallet  10 . 
     A non-slip or anti-skid treatment surface may be applied on the top facing surface of the deck panels  18 ,  22  and of the central slat  20  (i.e. the deck surface in contact with the merchandise to be carried on the pallet). The anti-skid treatment may take the form of small convex embossments or protrusions on the top web surface of the corrugations as for instance shown at  48  in  FIG. 5 . Arrays of spaced-apart elongated embossments  48  may be formed along the top web of selected corrugations. According to one example, the embossments have a 1 mm height and a 5 mm length. According to one embodiment, more than 550 embossments are distributed over the deck of the pallet  10  to provide a better adherence and, thus, a better stability of the merchandise on the pallet  10 . 
     Like the top panels  18 ,  22 , the top slat  20  is corrugated. The corrugations of the slat  20  may also have a generally trapezoidal shape. According to one embodiment, the pitch of the corrugations of the slat  20  is equal to 27 mm. The slat  20  may have opposed longitudinal downwardly sloping edge portions  50 . The sloping edge portions  50  may define a 45 degrees slope. The sloping edge portions  50  may be folded upon themselves to provide a 2-ply edge structure as described above with respect to the panels  18 ,  22 . 
     The corrugations of the bottom slats  32  forming the base  14  of the pallet  10  may be generally similar to the corrugations of the top slat  20  and the side corrugations  40  of the panels  18 ,  22  (similar depth and pitch). As can be appreciated from  FIG. 4 , downwardly sloping wing-like projections  52  extend between the mounting flanges  34  along the opposed longitudinal sides of each slat  32 . The wing-like projections  52  extend downwardly at an appropriate angle (e.g. 45 degrees) to form raceways to facilitate the entry of pallet handling equipment (e.g. forks of a forklift truck) in the end entries of the pallet. The wing-like projections  52  may have a 2-ply configuration by folding over a portion of the lateral edge portions of the slats  32  upon themselves. This provides for a more robust raceway construction for absorbing impact forces. The mounting flanges  34  also contribute to render the wing-like projections  52  more robust. 
     As mentioned hereinbefore, each beam  16  has a V-shaped open-top section. 
     The V shape of the beams provides added resistance to buckling under high-stacking loads. The V-shaped beams provide a rigid and sturdy bridge between the top and bottom sections of the pallet  10 . According to an embodiment, an angle of about 30 degrees is defined between the sidewalls of each beam  16 . Still according to this embodiment, the height of each beam is equal to 90 mm. The top lateral flanges  28  used to attach the beams  16  to the top panels  18 ,  22  and the top central slate  20  may have a 2-ply configuration. As described above with respect to the panels  18 ,  22  and the slates  20 ,  32 , the 2-ply configuration may be obtained by folding over the side edge portions of the sheets of galvanized steel used to form the beams  16 . As shown in  FIGS. 1, 3 and 6 , a pair of elongated arched openings  58  may be defined in the sides of each beam  16  for providing side entries for pallet handling equipment. The pallet shown in  FIG. 1  with the side entries and the end entries is a four-way entry pallet that can be lifted from any sides thereof. As can be appreciated from  FIGS. 6 and 7 , the openings  58  may be provided by pressing or deep drawing a portion of the material of the flat bottom end  30  of the beams between the diverging sides or legs of the beams. 
     The material pressed into the V-shaped section of the beams (i.e. the die formed portions) can be seen at  60  in  FIG. 7 . The die formed portions may include a central arch  60   a  and a pair of secondary arches  60   b ,  60   c  on opposed sides of the central arch  60   a . These die formed portions also contribute to strengthen the beams  16 . 
     A shape transformation process that can be used to form the transversal arched openings  58  in the beams  16  is shown in  FIGS. 9 a  to 9 d   . First, a sheet metal workpiece W is folded into a V-shaped elongated beam member. Then, as shown in  FIG. 9 a   , the pre-folded sheet metal workpiece W is seated face down on a die D and held thereon by a blank-holder H. Thereafter, as shown in  FIG. 9 b   , a central punch CP is lowered to press the underlying portion of the flat bottom end of the inverted-V-shaped workpiece W into a corresponding central cavity defined in the die D, thereby providing for the formation of the central arched  60   a . As can be appreciated from  FIG. 7 , the central arch  60   a  is fully accommodated within the internal volume defined between the legs of the cold formed V-shaped beam  16 . In the illustrated example, the height of the central arch  60   a  corresponds to the height of the legs (i.e. the top surface of the central arch is leveled with the mounting flange  28 ). It is understood that the central arch  60   a  must not project out of the top open end of the beam in order not to interfere with the mounting of the deck to the flanges  28 . In order to further increase the height of the arched openings  58 , a pair of secondary punches SP disposed on opposed sides of the central punch CP are pushed into the workpiece material to draw the material adjacent to the previously formed central arch  60   a  into corresponding cavities defined in the die D. This result in the formation of secondary arches  60   b ,  60   c  on opposed sides of the central arch  60   a . As can be appreciated from  FIG. 7 , the height of the secondary arches  60   b ,  60   c  is less than that of the primary arch  60   a . The central arch  60   a  and the secondary arches  60   b ,  60   c  cooperate to further strengthen the beam. Finally, as shown in  FIG. 9 d   , the central punch CP and the secondary punches SP are withdrawn from the workpiece W to permit subsequent removal of the so cold formed arched beam from the die D. 
     The above shape transformation process with material retention provides for the formation of strong beams with lateral entry features for the pallet. It is understood that other suitable stamping or press forming processes could be used to form the arched openings with material retention of the plastically deformed zones within the internal volume between the legs of the beam. 
     The remaining land of material between the adjacent arched openings  58  and at the outer ends thereof provide the required mounting surfaces for the transversal slats  32  of the base  14 . 
     As shown in  FIG. 6 , the edge portions  62  at the opposed longitudinal ends of the legs of each beam may be folded inwardly at right angles to provide additional protection to the beams  16  against collisions. 
     As shown in  FIG. 8 , similar pallets  10   a ,  10   b ,  10   c    10   d ,  10   e  . . . may be stacked one upon another with the downwardly projecting ridges of the corrugations formed in the bottom slats  32  fitting in corresponding troughs of the side corrugations  40  of the deck panels  18 ,  22  and of the central top slat  20 . This nesting engagement between the corrugations of the pallets provides for added stacking stability. It also provides for a more compact stacking arrangement than conventional wooden pallets. 
     Advantages of the above described metal pallet constructions comprise: load bearing capability, durability, recyclable, sanitary, easy to clean, light weight and robust, fire resistant, thermally stable and re-usable. 
     The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. For instance, any suitable metal material, such aluminum could be used to form the pallet. Also, depending on the size of the pallets, a different number of arched openings could be formed in the beams  16  to permit side entries of material handling equipment. Also, only the peripheral beams (the one along the sides of the pallet) could be provided with the side openings. It is also contemplated to manufacture a pallet without the corrugated bottom slat. Other modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims.