Abstract:
A containment tray for a hazardous material spill pallet for storage of hazardous material containing drums. The tray provides a raised support surface for the drums and a chamber for containing spilled or leaking material from the stored drums. Access for pallet lifting member is provided from all four directions of the pallet. The containment trays are nestable for stacking and peripheral edges are reinforced for more solid support when in use and when stacked. Multiple channels along the peripheral edge are provided for attachment of auxiliary devices such as a ramp for ease of placing and removing drums.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to pallets, for supporting hazardous material containing drums, which provide a chamber for receiving and retaining hazardous material which is spilled or leaked from the supported drums. 
     2. Description of the Related Art 
     Spill pallets or other devices for containment are required by various governmental agencies for storing materials which are considered hazardous to the environment. The materials are commonly stored in metal or plastic drums and a spill pallet must include a chamber for retaining a specified volume of material depending on the number and size of the drums being stored on the pallet. Various devices are known from a simple tub to more complex devices. An improved device, enabling easier handling of the drums, features a raised grate for supporting one or more drums with a retaining chamber beneath it; channels are provided in a lower portion of the chamber for entry of fork lift tines for ease of movement. Another feature found in various pallets is the ability to nest the pallets for stacking when a large number of pallets are stored for future use or stacked to occupy a minimum amount of space for shipping from a pallet manufacturer to a user. 
     The spill pallet of the present invention provides a drum support surface with an underlying containment tray and means for fork truck access to the support surface. It is configured so as to be stackable in a nested arrangement. Additional features include supports in a peripheral portion of the containment tray to provide sufficient vertical support for sizeable quantities of containment trays stacked above it, and channels provided in the peripheral portion of the containment tray for positively engaging a ramp for facilitating movement of drums from or to the pallet with use of a drum dolly or the like. The pallet is of a low profile while providing the retaining capacity required by governmental regulations. 
     SUMMARY OF THE INVENTION 
     The present invention is a containment tray for a hazardous material spill pallet for storing drums of hazardous material supported on a removable grate placed on the containment tray. A bottom wall and side walls extending therefrom form an open-top fluid-receiving chamber. Recesses in the bottom wall define open channels for entry of pallet lifting means such as fork lift tines. A grate, upon which the drums are stored, is at least partially supported by support posts which are offset from the center and extend upwardly from the bottom wall. A ledge, extending outwardly from the side walls, also supports the grate. An L-shaped flange extends upwardly then inwardly from an outer periphery of the ledge, and columns, which give strength to the L-shaped flange, are positioned at various locations along the flange. 
     Other specific features and contributions of the invention are described in more detail with reference being made to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top perspective view of a spill pallet including a containment tray of the invention, with a drum support grate in place on the containment tray and a ramp engaged on one side of the pallet; 
     FIG. 2 is a top perspective view of the spill pallet of FIG. 1 without the ramp in place; 
     FIG. 3 is a top perspective view of the containment tray of the invention with the drum support grate removed so as to reveal details of the containment tray; 
     FIG. 4 is a bottom perspective view of the containment tray of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is to a containment tray for use in a hazardous material spill pallet. FIG. 1 shows spill pallet  12  which is made up of containment tray  14  and support grates  16 . Grates such as those described in U.S. Pat. No. 5,375,537 can be used with the present invention. An auxiliary device, ramp  18 , is attached to the spill pallet at  20  and  22 . FIG. 2 shows the spill pallet with the ramp removed. A plurality of drums containing hazardous material (not shown) are supported on the horizontally oriented support surface of grate  16  when in use. In the event of leakage of hazardous material from a drum or spillage during use of the hazardous material from a drum, the material, typically in liquid form, drains through the many apertures  24  of the grate and into the containment tray  14 . FIG. 3 shows the containment tray  14  without the support grates in place, so as to expose a containment chamber  26  into which the hazardous material flows. The capacity of the containment chamber is in accordance with current EPA requirements. 
     The containment tray of the invention is preferably fabricated by rotational molding, however other methods of molding such as blow molding are available. The preferred material of the tray is polyethylene although other thermoplastic materials, can be used. The thickness of the molded material is between about 0.2 and 0.25 inches. 
     Containment tray  14  has a bottom wall  28 , and side walls  30  which extend generally upwardly from the periphery of the bottom wall, so as to form an open-top fluid receiving and retaining chamber. Walls  30 , which extend in various horizontal directions, extend completely around the periphery of bottom wall  28 . For purposes of this disclosure, a generally rectangular four drum spill pallet is described, however features of the invention are applicable to spill pallets of other dimensions. A preferred embodiment of the invention is a generally square shaped pallet which is symmetric about its center. Side walls  30  extend upwardly and slightly outwardly at an angle of from 10° to 15° from perpendicular to the bottom wall. The slight outward angle enables nesting of one tray within another. Nesting permits a large number of trays to be placed in a stacked condition for storage or shipping thus conserving valuable space and reducing shipping expenses. In the preferred embodiment, that is with symmetry about its center, the trays are nestable without regard for alignment of a particular edge of each tray. 
     At selected portions of the bottom wall, bottom wall recesses  32  are formed which define external facing open channels  34  (FIG. 4) for insertion of pallet lifting means. Channels  34  are best viewed in FIG. 4 which is a bottom perspective view of the containment tray. The channels provide access from all four sides of the spill pallet for lifting means which most commonly consist of tines of a fork lift. 
     Projecting from the bottom wall, at locations offset from the center portion of the containment tray, are a plurality of support posts  36 , for at least partially supporting grate  16 , when in place. The support posts are positioned intermediate the tray center and the side walls  30 . Each post includes a grate support surface  38  which lies in a grate support plane defined by surfaces  38 . Side walls of support posts  36 , like side walls  30  extending from bottom wall  28 , are inclined at about 10°-15° from perpendicular to the bottom wall so as to enable nesting as discussed above. One of the side walls,  39 , of each support post  36  extends from grate support surface  38  downwardly to a bottom wall recessed portion  32 . With such a configuration, the load on the support post is at least partially bearing on the bottom wall recess, which is more solidly supported from beneath the spill pallet than the remaining bottom wall (non-recessed) of the tray from which the remaining three side walls of the support post extend. 
     The periphery of the grate  16  is supported by ledge  40 , which extends outwardly from top edges of the side walls  30  and lies in the grate support plane. The combined support provided by the support posts and ledge give ample support to the grate when installed and loaded with drums of hazardous material. The absence of additional support members adds to the volume of the retaining chamber so as to achieve the required volume yet present a spill pallet of a relatively low profile in relation to other spill pallets known in the art. A large portion of side wall  30 , which extends upwardly and supports ledge  40 , extends from bottom wall recessed portions  32  so as to provide a more solid ledge in light of the solid support from beneath the spill pallet as discussed above. 
     A peripheral L-shaped flange  42  extends upwardly and inwardly from an outer periphery of ledge  40 . The flange has a substantially vertically oriented face  44  and a substantially horizontally oriented face  46 . In a preferred embodiment of the spill pallet, a plane defined by horizontally oriented face  46  coincides with the top supporting surface of grate  16  when disposed on the spill pallet. Having the entire horizontal surface of the spill pallet (face  46  of flange  42  and top surface of grate  16 ) in a single plane facilitates use of the pallet, especially when drums are placed or removed from the pallet with means such as a drum dolly or the like. 
     To add vertical support to flange face  46 , a plurality of flange supports  48  are formed by walls  50  which extend between ledge  40  and flange face  46 . In the preferred embodiment, three walls are present for each flange support and  16  flange supports are provided in the tray. The flange supports are particularly useful for adding vertical strength to flange face  46 , which is needed if a drum is partially supported by the ledge  40  or more importantly for added strength needed when the trays are nested to form a tall stack of trays for storage or shipping purposes. 
     In addition to the three walls extending from ledge  40  to flange face  46 , a fourth wall  52 , L-shaped in configuration, extends upwardly from ledge  40  and then outwardly toward vertical face  44 . The upwardly extending portion does not extend all the way upward to horizontal face  46 , but turns to extend outwardly, short of face  46 , so as to create an inwardly directed channel  53  at each flange support. That channel,  53 , provides a location for attaching attachment means of ramp  18  to the spill pallet (see FIG.  1 ). In the preferred embodiment, the flange supports are generally square in shape and are open at the top and bottom, as best seen in FIGS. 3 and 4 as indicated at  48  and  54  respectively. 
     The flange supports  48 , function also to provide a centering means for grates  16 . One of the walls forming the flange support, that is the wall facing toward the grates, for example wall  56  in FIG. 3, bears against edges of a grate  16  so as to maintain it centered on the spill pallet. Without that centering means the grate could slide under the horizontally oriented face  46  of the L-shaped flange  42 . 
     In order to provide vertical support between the surface on which the spill pallet is placed and ledge  40 , and in turn to the horizontally oriented face  46  of L-shaped flange  42 , the side wall  30 , which extends in various horizontal directions, is routed, as best viewed in FIG. 4, to form support ribs  60 . At those rib locations, the side wall is extended out almost to the outer edge of ledge  40  to provide adequate vertical support to the ledge. In the preferred embodiment, three support ribs are provided per side of the containment tray. The walls of the support ribs extend from portions of the bottom wall in which bottom wall recesses are positioned so as to have more solid bearing, as discussed above. 
     In order to enable nesting of the containment trays the horizontally oriented face  46  of the L-shaped flange  42  has periodic gaps, such as at  58  in FIG. 3, to accommodate the support ribs  60  of an adjacent nested containment tray. 
     While specific materials, methods of fabricating and configurations have been set forth for purposes of describing an embodiment of the invention, various modifications can be resorted to, in light of the above teachings, without departing from applicant&#39;s novel contributions; therefore in determining the scope of the present invention, reference shall be made to the appended claims.