Patent Publication Number: US-6983846-B2

Title: Top frame assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of application Ser. No. 09/576,163 filed on May 22, 2000 U.S. Pat. No. 6,651,815. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a top frame assembly. 
     BACKGROUND ART 
     A top frame is typically used in conjunction with a pallet for the mass shipping of objects. The top frame is placed on top of a load to stabilize the load for shipment. The top frame is typically used in conjunction with a pallet which is positioned at the bottom of the same shipment. Until recently, top frames were made of wood. However, recent top frames have been molded in plastic. U.S. Pat. No. 5,160,029 by Pigott et al. discloses a plastic top frame used in association with palletized goods. The top frame is subject to stress and torsional forces, and other types of load, such as those forces placed upon the top frame by strap (S). This top frame use a series of open rib for reinforcement. However, over a period of extended use, the structure of this top frame may not have sufficient strength and may tend to deform or fracture under such stress and bending 
     Accordingly, an improved top frame is desired which is able to withstand a relatively high amount of load, stress, torsional forces, and bending to which a top frame is subjected. 
     DISCLOSURE OF INVENTION 
     It is an object according to the present invention to provide a top frame which is able to withstand a relatively high amount of stress and torsional forces. 
     It is another object according to the present invention to provide a top frame assembly which has at least one insert member for providing strength and reinforcement to the top frame assembly. 
     It is yet another object according to the present invention to provide a top frame assembly which receives an insert member for providing strength and reinforcement to the top frame assembly. 
     In keeping with the objects and goals according to the present invention, an improved top frame assembly is provided which includes a frame portion which defines a receiving compartment therein, and at least one insert member, but preferably a plurality of insert members, which is disposed within the compartment of the frame for providing strength thereto. The insert member is preferably metal. The frame may have generally rectangular perimeter, wherein the at least one insert member extends along at least one side of the generally rectangular perimeter. In another embodiment, the frame may include a pair of planar members having a plurality of rib members extending therebetween. The frame may also include a top member and a bottom member, where the top member has an upper surface and a first opposed mating surface, and the bottom member has a lower surface and a second opposed mating surface, where the first and second opposed mating surfaces are welded together. 
     Another embodiment of top frame assembly includes a top member which has a top surface and a first mating surface, a bottom member which has a bottom surface and a second mating surface which corresponds to and mates with the first planar mating surface. Also included is at least one insert member disposed between the first and second mating surfaces for enhancing the strength of the top frame assembly. The insert member is preferably a metallic insert and includes a planar portion. In this embodiment, the top member may have a first pair of opposed side members including the first mating surface, and the bottom member has a corresponding second pair of opposed side members which includes the second mating surface, such that the at least one member is a pair of inserts each of which is disposed between a respective first and second pair of opposed side members. The top surface and bottom surface preferably are each planar and oriented parallel to each other, and the first and second mating surfaces may be defined by corresponding cross-rib patterns. In such an embodiment, the first and second planar mating surfaces are attached to each other such that the corresponding cross-rib patterns define a plurality of whole box beam sections extending across the top frame assembly. 
     This embodiment may also include a top member which has a generally rectangular upper perimeter member which includes the first mating surface, and a bottom member which has a generally rectangular lower perimeter member which corresponds to the upper perimeter member, and wherein the lower perimeter member includes the second mating surface. 
     In still another embodiment according to the present invention, a top frame assembly is provided which includes a first planar member having a first mating surface, a second planar member having a second mating surface for attaching to the first mating surface, wherein one of the first and second mating surfaces is defined by a rib pattern, which may also include a cross-rib pattern. Also included is at least one insert disposed between the first planar member and the second planar member to enhance the strength of the top frame assembly. The insert is preferably a metallic insert. In this embodiment, the first planar member may include a first pair of opposed side members which includes the first mating surface, and the second planar member which has a corresponding second pair of opposed side members including the second mating surface, such that the insert is a pair of inserts each of which is disposed between a respective first and second pair of opposed side members. 
     Further, in this embodiment, the first planar member may have a first outer surface and the second planar member has a second outer surface, such that the first and second outer surfaces are oriented parallel to each other. The first and second planar mating surfaces are attached to each other such that the rib pattern define a plurality of whole box beam sections extending across the top frame assembly. The top member may have a generally rectangular upper perimeter member which includes the first mating surface, and the bottom member may have a generally rectangular lower perimeter member which corresponds to the upper perimeter member, so that the lower perimeter member includes the second mating surface. 
     In still another embodiment according to the present invention, provided is a top frame assembly which has a pair of opposed side members and also includes a top member having a top pair of opposed side portions, a bottom member which is mounted to the top member and has a bottom pair of opposed side portions corresponding to the top pair of opposed side portions, such that the top and bottom pairs of opposed side portions mate with each other to define the pair of opposed side members. Also included is a plurality of insert members disposed between top and bottom pairs of opposed side portions for enhancing the strength of the top frame assembly. The inserts are preferably metallic and planar. The top member includes a top surface and the bottom member includes a bottom surface, such that the top and bottom surfaces are each planar and oriented parallel to each other. The top pair of opposed side portions include a first mating surface, and the bottom pair of opposed side portions include a second mating surface, such that at least one of the first and second mating surface is defined by a rib pattern, which may be a cross-rib pattern. 
     The first and second mating surfaces are attached to each other such that the mating surfaces define a plurality of whole box beam sections extending across the top frame assembly. In this embodiment, the top member may have a generally rectangular top perimeter member which includes the top pair of opposed side portions, and the bottom member may have a corresponding generally rectangular bottom perimeter member which includes the bottom pair of opposed side portions, and such that the top perimeter member includes a first mating surface and the bottom perimeter member includes a second mating surface for attaching to the first mating surface. 
     Provided according to the present invention is another top frame assembly which includes a first member having a planar first mating surface, a second member which has a planar second mating surface attached to the first mating surface, and at least one insert member having a planar portion and is disposed between the first and second members and oriented generally parallel to the first and second mating surfaces. Preferably, the insert is a metallic insert. The first member may have a first pair of opposed side members including the first mating surface, and the bottom member may have a corresponding second pair of opposed side members which includes the second mating surface, such that the at least one planar insert is a pair of inserts each of which is disposed between a respective first and second pair of opposed side members. The first member includes a first outer surface and the second member includes a second outer surface, such that the first and second outer surfaces are each planar and oriented parallel to each other. Also, at least one of the first and second mating surfaces may be defined by a rib pattern, and may include a cross-ribbing pattern. Still further, the first and second mating surfaces are attached to each other such that the mating surfaces define a plurality of whole box beam sections extending across the top frame assembly. Still further, the first member has a generally rectangular first perimeter member which includes the first mating surface, and the second member has a generally rectangular second perimeter member which corresponds to the first perimeter member, and where the second perimeter member including the second mating surface. 
     Also provided in accordance with the present invention is a top frame assembly having an upper frame portion having a generally rectangular upper perimeter member with a first mating surface, a lower frame portion having generally rectangular lower perimeter member corresponding to the upper perimeter member, the lower perimeter member having a second mating surface attached to the first mating surface. Also included is a plurality of planar insert members disposed between the first and second mating surfaces for enhancing the strength of the top frame assembly. The upper perimeter member has a first pair of opposed side members including the first mating surface, and the lower perimeter member has a corresponding second pair of opposed side members including the second mating surface, such that each of the plurality of inserts is disposed between a respective first and second pair of opposed side members. The upper perimeter member may also include a first outer surface, and the lower perimeter member may include a second outer surface, such that the first and second outer surfaces are each planar and oriented parallel to each other. One of the first and second mating surfaces may be defined by a rib pattern. The first and second mating surfaces are attached to each other such that the rib pattern defines a plurality of whole box beam sections extending across the top frame assembly. 
     The above objects and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of the top frame assembly according to the present invention; 
         FIG. 2  is a top plan view of the top frame of  FIGS. 1–3 , the bottom plan view being a mirror image thereof; 
         FIG. 3   a  is an exploded perspective assembly view of the top frame assembly according to the present invention and particularly illustrates an insert between the upper and lower top frame members according to the present invention; 
         FIG. 3   b  is a perspective view of one top frame portion according to the present invention having a plurality of inserts disposed thereon; and 
         FIG. 4   a  is an exploded, enlarged, partial perspective view of the bottom member of the top frame shown in  FIG. 4   a  having the first embodiment of the insert separated therefrom; 
         FIG. 4   b  is an enlarged, partial perspective view of the bottom member of the top frame assembly having the first embodiment of the insert positioned thereon; 
         FIG. 5   a  is a partial cross-sectional view of the top frame assembly taken along line A—A of  FIG. 3   b , illustrating the first embodiment of the insert member shown in  FIGS. 3   a – 3   b;    
         FIG. 5   b  is a full cross-sectional view of the top frame assembly shown in  FIG. 5   a , taken along the line B—B of  FIG. 2 ; 
         FIG. 6   a  is a partial cross-sectional view of the top frame assembly similar to that of  FIG. 5 , illustrating a second embodiment of the insert member; 
         FIG. 6   b  is a full cross-sectional view of the top frame assembly similar to that of  FIG. 6   a  with the second embodiment; 
         FIG. 7   a  is a partial cross-sectional view of the top frame assembly similar to that of  FIG. 5 , illustrating a third embodiment of the insert member; 
         FIG. 7   b  is a full cross-sectional view of the top frame assembly similar to that of  FIG. 7   a  with the third embodiment; 
         FIG. 8   a  is a cross-sectional view of the top frame assembly similar to that of  FIG. 5 , illustrating a fourth embodiment of the insert member; 
         FIG. 8   b  is a full cross-sectional view of the top frame assembly similar to that of  FIG. 8   a  with the fourth embodiment; 
         FIG. 9  is a partial cross-sectional perspective view of the bottom member of the top frame assembly showing adjacent side and end members, each having an insert member disposed thereon; 
         FIG. 10  is another partial cross-sectional perspective view of the bottom member of the top frame assembly showing adjacent side and end members similar to  FIG. 9 , the end members having a vertically oriented insert and the side members having a horizontally oriented insert; 
         FIG. 11  illustrates a partial cross-sectional view of the top frame assembly taken along line C—C of  FIG. 3   b  through the hole of the insert member, illustrating the first embodiment of the insert member shown in  FIGS. 3   a – 3   b;    
         FIG. 12  is a perspective cross-sectional view of a side of the top frame assembly which does not include an insert member disposed between the upper and lower top frame members, taken along line D—D of  FIG. 2 ; 
         FIGS. 13   a–f  illustrate the method according to the present invention of forming and assembling the top frame assembly; 
         FIG. 14  is a side elevational view of a top frame assembly in use in conjunction with a pallet, and having layers of objects with slip sheets disposed therebetween; 
         FIG. 15   a  is a perspective view of another embodiment of the top frame assembly according to the present invention; 
         FIG. 15   b  is a cross-sectional view taken along line E—E of  FIG. 15   a;    
         FIG. 16   a  is a perspective view of still another embodiment of the top frame assembly according to the present invention; 
         FIG. 16   b  is a cross-sectional view taken along line F—F of  FIG. 16   a;    
         FIG. 17   a  is a perspective view of yet another embodiment of the top frame assembly according to the present invention; 
         FIG. 17   b  is a cross-sectional view taken along line G—G of  FIG. 17   a;    
         FIG. 18   a  is a perspective view of another embodiment of the top frame assembly according to the present invention having a cross-member therein; and 
         FIG. 18   b  is a cross-sectional view taken along line H—H of  FIG. 18   a.    
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Disclosed herein is a top frame assembly  10  according to the present invention, illustrated in  FIGS. 1–3 .  FIG. 1  illustrates a perspective view of top frame assembly  10 . Top frame  10  is preferably formed of a thermoplastic or other polymeric material and is also preferably, but not necessarily, formed by an injection molding process. Top frame  10  is shown in  FIGS. 1–3  as having a generally rectangular shape and also as being generally symmetrical about each centerline. However, it is fully contemplated that top frame assembly  10  may have various shapes and configurations without departing from the teachings according to the present invention. For example, top frame assembly  10  may also include one or more members or cross-members extending across central opening  26  (as illustrated in  FIG. 18   a .)  FIG. 2  illustrates a top plan view of top frame assembly  10 . 
     As best illustrated in the exploded perspective view of  FIG. 3   a , top frame assembly  10  includes an upper (first, top) member  12  and a lower (second, bottom) member  14  which correspond to and mate with each other. Particularly, as illustrated in  FIGS. 2 ,  3   a  and  5   b , upper member  12  has a flat, planar upper surface  16 , and also includes a lower (first mating) surface  18 . Lower member  14 , on the other hand, includes a planar lower surface  20  and also includes an upper (second mating) surface  22 . With further reference to  FIG. 5   b , mating lower surface  18  of upper member  12  mates with and attaches to corresponding upper surface  22  of bottom member  14 . More particularly, planar mating surface  18  of upper member  12  is generally defined by outer edge  19  which is a downwardly projecting flange member which extends around the perimeter of upper member  12 , and also by inner edge  21  which is also a downwardly projecting flange member which extends around the interior of upper member  12  and helps define opening  26 . As shown in  FIGS. 5   b ,  6   b ,  7   b ,  8   b , upper member  12  may also include ribs  24  which generally correspond to and mirror those ribs  25  of bottom member  14  shown in  FIGS. 3   a  and  3   b  and which are also generally co-planar with outer and inner edges  19 , 21 . 
     With regard to lower member  14 , planar mating surface  22  of lower member  14  is generally defined by outer edge  29 , which is an upwardly projecting flange member  29  (which extends around the perimeter of lower member  14  and corresponds to upper mating flange  19 ), and is also defined by inner edge  31  which extends around the interior of lower member  14  and corresponds to mating flange  21 . Those ribs  27  disposed below insert members  80  are generally not co-planar with edges  29 , 31 , as shown in  FIGS. 5   a ,  6   a ,  7   a ,  8   a . However, ribs  25  in corner portions  35  which do not have an insert member according to the present invention may be fully co-planar with edges  29 , 31 . Ribs  25  and  27  may of course include cross-ribbing as shown in  FIGS. 3   a – 3   b . Also, it is fully contemplated that one of upper member  12  and bottom member  14  may have a ribbing pattern, including cross-ribbing, while the other may include a mating surface  18 , 22  which is planar sheet of plastic without ribs which is welded or attached to the opposed mating surface. 
     With reference to  FIG. 1 , in the embodiment illustrated, top frame assembly  10  has a central opening  26  defined by an outer rail  28 , which includes a first pair of opposed side members  30 , 32  and a second pair of opposed side members  34 , 36 . For ease of reference, the first pair of side members may be referred to as side members  30 , 32 , while the second pair of opposed side members may be referred to as end members  34 , 36 . Referring again to  FIGS. 3   a  and  3   b , side member  30  is defined by upper side member  38  and lower side member  40 . Side member  32  is defined by upper side member  42  and lower side member  44 . End member  34  is defined by upper end member  46  and lower end member  48 . End member  36  is defined by upper end member  50  and lower end member  52 . 
     Further, with reference to  FIG. 1 , side members  30 , 32  respectively include a first pair of opposed outer edges  54 , 56  (side edges), while end members  34 , 36  respectively include a second pair of opposed outer edges  58 , 60  (end edges). Referring again to  FIGS. 2 ,  3   a  and  3   b , edge  54  is defined by upper member and lower member edges  62 , 64 , respectively. Edge  56  is defined by upper member and lower member edges  66 , 68 , respectively. Edge  58  is defined by upper member and lower member edges  70 , 72 , respectively. Edge  60  is defined by upper member and lower member edges  74 , 76 , respectively. Upon welding or fastening members  12 , 14  together according to the present invention, a parting line  78  results between the respective mating edges. (See  FIG. 1 .) Outer edge  19  of upper member  12  includes edge portions  62 ,  66 ,  70 , and  74 , while outer edge portion  29  of lower member  14  includes edge portions  64 ,  68 ,  72 , and  76 . 
     As illustrated in  FIGS. 3   a ,  3   b ,  4   a ,  4   b ,  5   a , and  5   b  and in accordance with the present invention, top frame assembly  10  also includes at least one, but preferably a plurality, of insert members  80  which provide and enhance the strength, reinforcement, and stiffness properties of top frame assembly  10  (see also the other embodiments of the insert member illustrated in  FIGS. 6   a ,  6   b ,  7   a ,  7   b ,  8   a , and  8   b .) As illustrated in  FIGS. 3   a – 3   b , a pair of elongated, longitudinally extending insert members  80  are shown disposed in a generally planar orientation between upper member  12  and bottom member  14  such that it is sandwiched between both mating surfaces  18 , 22  and generally parallel thereto. For example, as illustrated in  FIGS. 3   a – 3   b , insert member  80  is positioned between each corresponding pair of rail upper and lower side members  38 , 40  and  42 , 44 . 
     Insert member  80  is preferably formed of metal, but may be also formed of composite or structural plastic, or any other material providing the desired properties. In one embodiment of a rectangular top frame assembly  10  which is  56  inches long, 44 inches wide and 1.5 inches deep, insert  80  centrally disposed within side members  30 , 32  and is 52 inches long, 3.5 inches wide, and 0.025 inches thick. With reference to  FIGS. 3   a  and  3   b , insert  80  is illustrated as extending along the length of each of the side members  32 , 34  (and positioned between slide members  38 , 40  and  42 , 44 ) whereas no insert is shown along the end members  34 , 36  (or between end members  46 , 48  and  50 , 52 .) Also, while no portion of insert member is shown extending into the corner areas  35 , in other embodiments it may extend across top frame assembly  10  and into the corner areas. Prior to attaching upper member  12  and lower member  14 , insert member  80  extends widthwise between outer edge  29  and inner edge  31  of lower frame member  14 . 
     Thus, after insert member  80  or plurality of insert members  80  are positioned on the desired side rails of either the upper or lower member ( 12  or  14 ), the members  12 , 14  are heated and introduced to each other as described herein in association with  FIGS. 13   a – 13   f . Note that insert members  80  are illustrated as being generally solid and continuous, except for a plurality of holes  82  and notches  84  formed therein. Because of the generally solid and continuous nature of insert members  80 , the majority of the inner rib pattern or structure of those portions of rail  28  which are covered by insert  20  are therefore not able to mate with the corresponding rib structure. For example, in  FIGS. 3   a  and  4   a , the ribs along lower side members  40 ,  44  (such as plurality pattern of ribs  79  and  81 ) are covered by insert member  80  and thus they will not mate with or weld with the corresponding mating ribs  24  of upper side members  38 , 42 , respectively (see also  FIGS. 5   b ,  6   b ,  7   b , and  8   b .) In those areas, the welding takes place along side members  30 , 32 , by way of welding together upper and lower outer edges  19 , 21 , and also the co-planar upper and lower inner edges  29 , 3 . In areas having insert member  80  disposed therebetween, the welding or attachment may also take place through portions of ribs  25  which are exposed through holes  82  and notches  84  in insert member  80 , and thus are able to mate and be welded together in these areas for greater surface area attachment between upper and lower members  12 , 14  (best shown in the cross-sectional view of  FIG. 10  taken through hole  82  in insert  80 , and also shown in  FIG. 4   b .) 
       FIG. 5   a  is an enlarged, partial cross-sectional view of the bottom member of the top frame assembly having the first embodiment of planar, flat insert member  80  positioned thereon, taken along line A—A of  FIG. 3   b .  FIG. 5   b  is a cross-sectional view of the top frame assembly taken along line B—B of  FIG. 2 , illustrating the first embodiment of the insert member shown in  FIGS. 3   a ,  3   b ,  4   a , and  4   b.    
       FIGS. 6   a ,  6   b ,  7   a ,  7   b ,  8   a  and  8   b  and  8 – 10  illustrate other various possible designs and embodiments of the. insert member according to the present invention. Of course, the various insert member embodiments are illustrated by way of example and not limitation, as the insert member disclosed herein may have any number of designs and configurations, the selection of which may be chosen based on the desired use, application, and properties of the top frame assembly. 
       FIG. 6   a  is a partial cross-sectional view of the top frame assembly similar to that of  FIG. 5   a , illustrating a second embodiment of the insert member  90  positioned upon side member  30  of rail  28 . As illustrated in  FIGS. 6   a – 6   b , insert member  90  is shaped like a “T”, having a flat planar portion  92  and a second planar portion  94  oriented perpendicular thereto, thus having portions  96 , 98  extending into upper member  12  and lower member  14 , adjacent inner walls  21 ,  31 .  FIG. 6   b  is a view similar to that of  FIG. 5   b.    
       FIG. 7   a  is a cross-sectional view of the top frame assembly similar to that of  FIG. 5 , illustrating a third embodiment of the insert member  100 .  FIG. 7   b  is a cross-sectional view of the top frame assembly similar to that of  FIG. 5   b , illustrating insert member  100 . As illustrated in  FIGS. 7   a – 7   b , from outer wall  21 , insert member  100  extends inwardly and has a flat planar portion  102  which transitions into an angled portion  104  extending into upper member  12 , and then has an end portion  106  which extends downwardly at 90° within lower member  14 , proximate inner wall  31 . 
       FIG. 8   a – 8   b  are other partial cross-sectional views of top frame assembly  10  similar to that of  FIGS. 5   a  and  5   b , illustrating a fourth embodiment of the insert member  110 . As shown therein, has a flat planar portion  112 , and an end portion  114  extending perpendicular thereto toward one of the upper member  12  and lower member  14 , and particularly shown oriented in a downward orientation. 
     In another embodiment according to the present invention, insert members according to the present invention are located on each of the side and end members  40 ,  44 ,  48 , and  52  of bottom member  14  of top frame assembly  10 , as shown in the partial cross-sectional view in  FIG. 9  of the symmetrical top frame assembly. As illustrated therein, an insert member  80  is disposed on each of the side members  40 , 44  and end members  48 , 52  for providing strength and resistance against deformation and buckling along each side. 
     In yet another embodiment shown in  FIG. 10 , side member  40  of bottom top frame member  14  includes an insert member  80  extending thereacross, as previously shown and described in association with  FIGS. 3   a  and  3   b . Moreover, end member  48  includes a vertically oriented insert member  120  (which, with reference to  FIGS. 6   a – 6   b , is similar to the vertically oriented portions  96 , 98  of insert member  90 , but does not have flat planar portion  92 .) In a rectangular top frame, the longer side members  30 , 32  may tend to deflect inward horizontally, or in a plane parallel to the insert member  80  or top surface  16 . Therefore, planar insert members  80 , or those substantially planar such as insert members  90 ,  100 ,  110 , may be used to provide strength and reinforcement in this direction. On the other hand, the shorter end members  34 , 36  may tend to bow or buckle under load (strapping forces), causing deflection in the vertical direction, or away from horizontal. Thus vertically oriented insert member  120  may be used to provide strength and reinforcement in those directions. In the embodiment of a top frame assembly  10  which is 56 inches long, 44 inches wide and 1.5 inches deep, insert member  120  may be 1.0 inch tall, 0.025 inch thick, and 40 inches long. 
     As shown in  FIGS. 6   a–b ,  7   a–b , and  10 , a portion of vertical insert members  90 ,  100 , and  120  may extend above planar surface  22 . Thus, if a hot plate welding process is used to assemble this top frame assembly as illustrated in  FIGS. 13   a–f , a groove maybe formed within the platen  326  to accommodate such upwardly extending portions of the various insert members. 
     Of course, it is fully contemplated that the insert members are not limited to those designs shown, but may have any shape or design in furtherance of the teachings according to the present invention. Also, any of the insert members disclosed and shown herein according to the present invention may be used in any area of top frame assembly  10  to provide the desired reinforcement, and are not limited to placement in those areas or top frame members disclosed. For example, any of the insert members may be used as desired to reinforce one or more of side and end members  30 , 32 , 34 , and  36 . In addition, should top frame assembly have members or cross-members extending across opening  26 , those members may also include insert members for reinforcement according to the present invention, as illustrated in  FIGS. 18   a–b . Further as illustrated in  FIGS. 15–17 , the teachings according to the present invention are not limited to two piece top frames which have an insert and are welded together, but may include any top frame having a reinforcing insert as disclosed and taught herein. 
     With reference to the cross-sectional views of  FIGS. 5   a ,  6   a ,  7   a , and  8   a , it is noted that the ribs  27 ,  81 ,  79  upon which the insert members rest have a lower height than the adjacent portions of outer and inner edges  29 , 31 , respectively (i.e. below surface plane  22 ). This allows the insert members  80  to be securely positioned within lower member  14  below planar surface  22 , prior to the welding process discussed below. As illustrated in  FIGS. 5   b ,  6   b ,  7   b  and  8   b , this allows the portions of edges  29 , 31  and ribs  25  to be plasticized during the welding process as disclosed further herein. In the other embodiments of insert members  90 ,  100 , and  110 , the lower profile rib portions  27  disposed below the insert members allow the relatively large flat, planar portion ( 92 ,  102 , and  112 ) of these insert members to be securely positioned therein. As shown in  FIGS. 5   b ,  6   b ,  7   b  and  8   b , after welding, the insert is preferably co-planar with the parting line  78 , but of course may vary due to welding and build variations. 
     According to the present invention, top frame members  12 , 14  are preferably fastened to each other by a hot plate welding operation, known in the art. (See  FIGS. 13   a – 13   f .) In these portions without inserts, the corresponding ribs on both members  12 , 14  are aligned so they preferably are welded together by plasticizing their mating surfaces to form box-beam sections, resulting in a top frame assembly where every section without an insert has a box beam. Note that the order of the plasticizing procedure is provided for illustrative purposes only, and of course, such steps may be performed in any feasible order. Also the plasticizing process for the top frame may also be accomplished by infrared radiation or another process designed to provide the desired properties of top frame  10 . 
     Attention is directed to the method of assembling top frame assembly  10  according to the present invention. The preferred manufacturing assembly process is by the hot plate welding process which is best illustrated in  FIGS. 13   a – 13   f  of the drawings. As indicated above, however, any suitable fastening means may be used such as, for example, infrared radiation, epoxy, etc. The hot plate welding process may be characterized as either contact hot plate welding or non-contact hot plate welding. This process should provide weld strength properties and produce seals between the mating (welded) components as strong as those of the parent polymer. According to the present invention, the top frame mating surfaces, are either placed in contact (in the contact hot plate welding process) or closely approach (in the non-contact variation) a heated platen  156  (preferably formed of steel) or similar tool in order to create a molten or plasticized region on the mating surfaces. Platen  156  is then moved out of the way and the plasticized regions are then pressed together to form the weld. 
     As illustrated in  FIG. 13   a , more particularly, in practice, the process is operated on a hot plate welding machine  150  (known in the art) in which the corresponding top frame  12 , 14  members which are to be welded together are securely attached by clamping in holding fixtures  152  and  154 . With reference to  FIG. 13   b , platen  156  of welding machine  150  is heated to a predetermined temperature and is extended between the separated upper member  12  and bottom member  14 . Holding fixtures  152  and  154  are moved toward each other and toward platen  156 , whereupon the weld planes of top frame members  12 , 14  are either pressed against platen  156  (by the contact version using conducted heat) or are moved closely to platen  156  (by the non-contact version using radiant heat.) The choice of which method to use is dependant on many factors including the properties of the materials to be welded; cycle times required; size and design of the component; accuracy and repeatability of the welding machine; and use of the welded component. 
     In the contact hot plate welding process, heat is conducted by way of physical contact of members  12 , 14  to be welded with heated platen  156  ( FIG. 13   c ). Further, the surface of each mating surface  18 , 22  is plasticized or melted until contact is complete (referred to in the art as “matching”). At this point, further platen  156  movement is often halted, and heating is continued, in order to create a deeper (to a predetermined depth), and relatively more molten, plasticized zone in which material is displaced. In the non-contact process,  FIG. 13   c  is disregarded and surfaces  18 , 22  do not contact platen  156 , but instead radiant heat is applied to the parts to be welded which is generated by holding the parts to be welded very close to the heated platen (target plates) and allowing them to heat over time. 
     With reference to  FIG. 13   d , for either version, after a predetermined period of time, heating is complete and the surface melting has reached a predetermined melt depth, the parts are retracted from platen  156 . Platen  156  is then moved out of the way, whereupon the adjoining top frame members  12 , 14  are forged together and held for a predetermined period of time until the plasticized material is stabilized and the mating surfaces cools. (See  FIG. 13   e .) Mechanical or microprocessor-controlled stops may be used to control the amount of material displacement of the top frame polymer from the weld zone, particularly during the heating phase. Finally, with reference to  FIG. 13   f , fixtures  152  and  154  are separated to their part loading position and welded top frame assembly  10  with insert contained therein, is held to one of the fixtures (shown in  FIG. 13   f  as fixture  154 ) for unloading. The part is then removed from welding machine  150 . 
     Weld times to form top frame assembly  10  may vary with the volume of polymer to be fused and the thermal conductivity of the respective top frame member. Accordingly, welding times for top frame assembly  10  may fall in the range from 5 to 60 seconds, although the mass of top frame members to be plasticized, the size and quantity of the insert members, and the corresponding cooling rates will govern cycle times. The size of top frame assembly  10  that may be hot plate welded according to the present invention is limited only by the practical size of holding fixtures  152  and  154  and platen  156  of welding machine  150 , and also of the mechanics of the removal of the welded assembly or subassembly from the weld zone and moving top frame assembly  10  components for forging them together. 
     Each of the contact and non-contact methods have their advantages, including: in the non-contact method, no special coating on platen  156  is required for material release, no residue builds-up on platen  156 , there is no loss of weld edge material against heated platen  156  and finished parts have consistent weld characteristics. Whereas, the advantages of contact heating are a quicker cycle time, lower temperature required for platen  156 , the method is more tolerant of larger design components, such as top frame assembly  10  disclosed herein, and also more tolerant of less dimensionally consistent components. 
     Welding top frame assembly  10  as described herein with insert  80  provides a high strength weld suitable for parts operating under pressure. The parting line  78  is relatively inconspicuous. Further, no other attachment methods, such as adhesives, solvents, mechanical fasteners such as nails or staples, are required. Also, complex shapes are capable of being welded since there is no relative motion required in the welding process. 
     Another assembly process known as infrared radiation may also be used as a non-contact alternative to hot plate welding for use in forming and assembling top frame assembly  10  according to the present invention. In such a process, the infrared radiation is often supplied by high intensity, quartz heat lamps which produce radiation having wavelengths of around one micron. As with hot plate welding, when this radiation is applied to mating surfaces  18 , 22  of top frame assembly  10 , plasticization of the surfaces occurs. In one application, radiation source, such as heat lamps, are removed after melting has occurred and the parts are forged together just as with the platen in hot plate welding. Infrared welding tends to melt the zone relatively quickly. Hot plate welding uses conduction to create the necessary plasticized zone. Of course, as with any other process, the depth of penetration of the plasticization depends on many factors and it varies strongly with only minor changes in polymer formulation. 
     As noted above, ribs  27 ,  79 ,  81  disposed below the corresponding insert members have a lower profile creating a pocket into which the insert member may be positioned prior to the above welding processes. However, it is also contemplated that ribs  27 ,  79 ,  81  upon which insert  80  rests, may be co-planar with edges  29 , 31  to assist in defining planar surface  22 . In this design, when the respective ribs  24 , 27  above and below the insert members  80  are plasticized, the upper and lower members  12 , 14  are held together for bonding, and the insert member displaces the plasticized material in those regions, thereby fitting between upper and lower members  12 , 14 , and also allowing for additional bonding between the plasticized top frame plastic and the metal insert member. 
       FIG. 14  shows a top frame assembly in operation. As illustrated therein, top frame assembly  10  according to the present invention is positioned upon a plurality of layers of objects for transport and storage, which are stacked upon a pallet. Such objects are shown in  FIG. 14  as a plurality of empty bottles  316 , but of course may be any of various objects which may be transported by and stored on pallet and to which the teachings according to the present invention apply, including cans. A first layer of bottles  316  is loaded on pallet  310 . Typically, a planar member  318  is positioned on the upper surface of bottles  316 . Planar member  318  may be referred to as a slip sheet in the art, and is typically formed of cardboard or fiberboard. As illustrated, another layer of bottles  316  maybe disposed on top of planar member  318 , and then another planar member  318  is positioned on top of that layer of bottles  316 . 
     This procedure is repeated for as many layers as is practical and desired, for example the eight layers of bottles shown in  FIG. 14 . After the final planar member is positioned, top frame assembly  10  is positioned on top of the planar member so that the product is sandwiched. Pallet  310  and top frame assembly  10 , with the objects disposed therebetween, are strapped together via straps  320 . As shown in  FIGS. 1 and 2 , top frame assembly  10  has recesses  86  and chamfered edges  87 , 89  around its sides in which straps  320  are positioned so that they do not move or easily slide off of the outer rail  28  during shipment. Subsequently, the resulting packaging (as shown in  FIG. 14 ) is typically covered and protected, such as by applying a shrink plastic wrap. Opening  26  of top frame assembly  10  assists in lowering the weight of top frame assembly  10  while the disclosed insert members  80  and box-beam sections provide the desired strength and rigidity to top frame  10 . 
       FIG. 12  illustrates that fastening together, or welding, each of the above respective pairs of ribs which are aligned define box-beam section walls of top frame  10 , in those areas of top frame assembly  10  which do not include an insert member  80 .  FIG. 12  is a perspective view shown as taken along line D—D of FIG.  2 . Thus, in embodiments where a portion of the top frame assembly does not include an insert member  80 , top frame assembly  10  includes box beam sections  77  (best shown in  FIG. 12 ) formed between top member  12  and bottom member  14  as illustrated in  FIG. 12 , in areas where no insert member  80  is located, such as the corner portions shown in  FIGS. 3   a ,  3   b , for example. In these non-insert areas, top frame assembly  10  also includes mating planar surfaces  18  and  22  which when fastened according to the teachings of the present invention define box beam sections therein as well as the parting line  78  between upper member  12  and bottom member  14 . Top frame assembly  10  also includes one or more holes  88  extending therethrough for receiving a grommet (not shown) therein for providing skid or slip resistance when stacking top frames. 
     Top frame  10  thus provides greater load stability and reinforcement which allows the objects  216  to be stacked higher and with greater stability. Further, with top frame  10  positioned and secured on top of the stack, it is contemplated that another pallet, such as pallet  210 , may be stacked on top of top frame  10 . The metal insert members  80 ,  90 ,  100 ,  110 , included within top frame assembly  10  provide improved stiffness, reinforcement, and strength to the part and minimize any bowing or flexing of the part, and also to minimize or prevent any deformation that would result from applying straps  320  to a prior art plastic or wood top frame. 
       FIGS. 15–16  illustrate another embodiment according to the present invention.  FIG. 15   a  illustrates a top frame assembly  170  according to the present invention which has a frame  178  formed of plastic and preferably formed by an extrusion process. Top frame  178  has a removable corner portion  171  which is preferably formed of injection molded plastic and covers the open ends  176  of each side portion  174 . One or more ribs  172  is shown extending down each side portion  174  of top frame assembly  170  from top surface  173  to bottom surface  175 , dividing side portion  174  into a plurality of cavities  177 ,  179 . As illustrated in the cross-sectional view of  FIG. 15   b  taken along the line E—E of  FIG. 15   a , an insert member  100 ′ (shown as similar to insert member  100 ) is inserted into one of the cavities (shown as cavity  177 ) from open end  176  and preferably extends along the length of side member  174 . Of course, an insert member may be received by the other cavity or both cavities without departing from the teachings herein. Further, an insert member may be received by any or all of side members  174 . 
       FIG. 16   a  illustrates yet another embodiment of a top frame assembly  180  according to the present invention, similar to that of  FIG. 15   a . Top frame  188  is formed of plastic and is preferably formed by an extrusion or blow molding process, in order to define hollow cavity  185 . Alternatively, any or all of the wall members which form each side portion  184  may be molded separately and welded together. As illustrated in the cross-sectional view of  FIG. 16   b  taken along line F—F of  FIG. 16   a , an insert member (for example insert member  100 ) is inserted into cavity  187  from open end  186  and preferably extends along the length of one or more side members  184 . Top frame assembly also has a top surface  183  and a bottom surface  185 . 
       FIG. 17   a  illustrates yet another embodiment of a top frame assembly  190  according to the present invention. Top frame  198  is formed of plastic by an extrusion process. The corners are then cut at the appropriate angles and attached or welded together. Prior to welding the frame side portions  194  together, an insert member is inserted therein, as illustrated in the cross-sectional view of  FIG. 17   b , taken along the line G—G in  FIG. 17   a , in which an insert member  100 ′ is received by at least one of the cavity portions  200 ,  201 ,  202  and  203 . 
       FIG. 18   a  illustrates still another embodiment of a top frame assembly  210  according to the present invention. Top frame assembly  210  is similar to top frame assembly  10  previously disclosed, with the addition of a cross-member  211 . Features similar to that of top frame assembly  10  have a corresponding reference number with the addition of a “2” prefix. As shown in the cross-sectional view of  FIG. 18   b , taken along lines H—H of  FIG. 18   b , the cross member  211  may be reinforced similar to the side and end rails, previously disclosed. Of course, any of the top frame embodiments disclosed herein may include cross members of any design or configuration. 
     While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.