BACKGROUND OF THE INVENTION

The present invention relates to pallet sized containers for the storage and transport of frozen, fresh, chilled or processed foods and other perishable or temperature sensitive products or materials. In particular, the invention relates to a method for insulating members of the container.

During the transport and storage of frozen, fresh, chilled or processed foods, such as seafood, bakery, candy, ice and other perishable or temperature sensitive products or materials, it is essential that the goods be kept at a prescribed storing temperature. To transport large volumes of temperature sensitive goods, refrigerator vans with individual freezing systems have been used. However, transport of small amounts of goods to one or a few retailers or consumers with a refrigerator van is expensive and slow. Because of high freight costs, many frozen goods are transported on conventional vehicles, which leads to quality losses and damaged goods.

To maintain temperature sensitive goods at the prescribed storing temperature without the use of an external power source, insulated chests have been utilized for the transport and storage of temperature sensitive goods. However, these chests are often incapable of handling larger quantities of goods packaged for wholesale distribution. Moreover, such chests are expensive to purchase or manufacture and are difficult to stack and handle with conventional material handling equipment such as forklifts. To accommodate larger wholesale quantities of goods and to permit easy material handling of such goods, pallet sized containers are often used for storing and transporting goods. Pallet sized containers have base and wall members which are formed from a variety of strong, supporting materials, including wood, metal and plastics. Pallet sized

containers formed from plastic, such as high density polyethylene, are advantageous because such containers are generally lightweight, resistant to damage caused by rust or rotting, and are inexpensive to manufacture. Plastic pallet sized containers are often formed by blow-molding a polymeric material, such as high density polyethylene, within a mold to form pallet sized members which are assembled together to make the container. The resulting container members have water-resistant, polymeric outer surfaces which completely surround and enclose a hollow interior. As a result, the pallet sized members are strong, yet lightweight. Although lightweight and strong, polymeric pallet sized containers often fail to adequately insulate and protect temperature sensitive goods contained within the pallet sized container. Consequently, the temperature sensitive goods must be maintained at the prescribed storing temperature with the use of an external power source, or the goods must be preheated or covered with a cooling substance such as ice. These heating and cooling mechanisms add weight, require additional space, and increase the storage and transportation costs of the temperature sensitive goods. SUMMARY OF THE INVENTION A container formed of support shells having an interior cavity. The interior cavity is filled with insulating foam. The shells include fill holes and bleed holes. Insulating foam is injected into the fill holes and the bleed holes allow air and gases to escape during injection of the insulating foam.

A jig for filling the support shells. The jig including a plurality of frame compartments sized to receive a shell element. The frame compartments including opposed shell element support members. The opposed shell element support members being spaced a distance apart similar to the thickness of a shell element. The opposed spaced shell element support members are supported by a support structure.

BRIEF DESCRIFΠON OF THE DRAWINGS

Fig. 1 is a perspective view of a pallet sized container of the present invention with portions broken away for clarity.

Fig. 2 is a perspective view of a side wall member of the container of Fig. 1 with portions broken away.

Fig. 3 is a perspective view of a drop gate member of the container of Fig. 1 with portions broken away.

Fig. 4 is a perspective view of an insulating system of the present invention including a jig, a plug, and a foam injector. Fig. 5 is a flow chart of a method for insulating members of a pallet sized container. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a perspective view of pallet sized container 10 with cover 12. Pallet sized container 10 is used for storing and transporting a variety of goods and products,* including temperature sensitive goods 14. Pallet sized container 10 is formed from various members including base 16, sidewall 18, drop gate wall 20 and drop gate 22. Each member 16-22 is preferably blow molded and thermal formed from a plastic or polymeric material such as high density polyethylene. As a result, each member is strong, lightweight, impact resistant and water resistant. Each member has a plurality of surfaces including a top surface 24, a bottom surface 26, inner surface 28 and outer surface 30. Outer surface 30 includes depressions 32 which extend inward towards inner surface 28. Depressions 32 increase structural strength of members 16-22 in container 10. As a result, depressions 32 increase the structural strength of container 10 so that container 10 may withstand large forces exerted upon container 10 by goods 14 within container 10 and by additional containers stacked above container 10. Inner surface 28 and outer surface 30 define hollow interior 34. Hollow

interior 34 extends along the entire length of each member 16-22 and encircles depressions 32. Hollow interior 34 is substantially filled with insulating foam 36.

Insulating foam 36 preferably consists of an expandable, liquid insulating foam such as 1.75 lb. polyurethane. Insulating foam 36 eliminates or minimizes dead air space within hollow interior 34. At the same time, insulating foam 36 increases the insulating effect of thermal efficiency of container 10. Consequently, temperature sensitive goods may be maintained at the prescribed storing temperature to reduce damage such as thawing and spoilage.

Upon assembly, members 16-22 form container 10. Base 16 generally comprises a rectangular base including legs 38. Preferably, base 16 includes three legs 38 on each side for supporting container 10. Legs 38 are preferably spaced apart from one another to permit forklift and pallet jack access. As a result, container 10 may be accessed by a forklift or pallet jack from any side of container 10 to speed the handling of container 10.

Side wall 18 and drop gate wall 20 are coupled to base 16 along joints 40a and 40b, respectively. Walls 18 and 20 are hingedly connected for selective connection and separation and radially rotate (as indicated by arrow 40c) about joints 40a and 40b, respectively, to permit walls 18 and 20 to be collapsed to improve space utilization and reduce shipping costs when not in use. As can be appreciated, walls 18 and 20 may alternatively be fixedly coupled to base 16.

Drop gate 22 is coupled to drop gate wall 20 near a top surface 24 of drop gate wall 20. Drop gate 22 is preferably hinged to drop gate wall 20 about hinge 42. Drop gate 22 radially rotates about hinge 42 so that goods 14 within container 10 may be more easily accessed.

FIGS.2 and 3 show perspective views of pallet sized members 18 and 22. In particular, FIG. 2 shows side wall 18. FIG. 3 shows drop gate 22. As best shown by FIG. 2, side wall 18 includes depressions 32, fill holes 50a, 50b, 50c and 50d, and bleed holes 52a, 52b, 52c, 52d. Depressions 32 are positioned along outer surface 30 of side wall 18 and extend toward inner surface 28 of side wall 18. Depressions 32 strengthen side wall 18 so that side wall 18 can withstand substantial loads or forces exerted upon it by goods contained within container 10 (shown in FIG. 1) and by other containers or goods stacked above container 10. Depressions 32 further prevent outer surface 30 of side wall 18 from bowing outward under high loads. In addition to strengthening side wall 18, depressions 32 interrupt hollow interior 34.

Fill holes 50a-50d are defined by top surface 24 of side wall 18. Fill holes 50a-50d communicate between top surface 24 and hollow interior 34 of side wall 18. Fill holes 50a-50d permit insulating foam to flow within hollow interior 34 so that side wall 18 may be insulated. Fill holes 50a-50d are equidistantly spaced apart from one another along top surface 24 of side wall 18. Alternatively, fill holes 50a-50d may extend through any surface 24-30. Fill holes 50a-50d are preferably formed by drilling into top surface 24 of side wall 18. As can be appreciated, fill holes 50a-50d may be formed by a variety of methods. Fill holes 50a-50d preferably have a diameter of about 1/2 inch.

Bleed holes 52a-52d generally consist of elongated, narrow slits cut into surfaces 24 and 30 of side wall 18. Bleed holes 52a-52d preferably have a length of about 1/2 of an inch to about 3/4 of an inch and a width of about 1/8 of an inch. As can be appreciated, bleed holes 52a-52b may have a .variety of shapes and sizes. Bleed holes 52a-52d permit air and gasses produced by the insulating foam during filling to escape from hollow

interior 34 of side wall 18. By allowing air and gas to escape, bleed holes 52a-52d prevent the formation of hollow pockets within the insulating foam as it is being injected into hollow interior 34. Consequently, hollow interior 34 of side wall 18 is more completely filled with insulating foam, i.e., a higher fill percentage, thereby causing side wall 18 to better insulate temperature sensitive goods within container 10. In addition, bleed holes 52a-52d indicate when portions of hollow interior 34 have been filled with insulating foam 36. Bleed holes 52a-52d permit an operator filling side wall 18 with foam to observe when certain portions surrounding each bleed hole 52 have been filled with the liquid insulating foam. Consequently, bleed holes 52a-52d allow side wall 18 to be more completely filled with insulating foam. Because bleed holes 52a-52c allow gasses to escape and indicate when portions of hollow interior 34 have been filled, portions of hollow interior 34 interrupted by depressions 32 are more easily filled. The number of unfilled, uninsulated portions of hollow interior 32 are thus reduced or eliminated. Consequently, side wall 18 better insulates goods within container 10.

In a preferred embodiment, bleed hole 52a extends through top surface 24 between fill holes 50a and 50b. Bleed hole 52d extends through top surface 24 between fill holes 50c and 50d. Bleed hole 52b extends through outer surface 30 approximately equidistantly from top surface 24 and bottom surface 26. Bleed hole 52c preferably extends through from surface 30 opposite bleed hole 52b. As can be appreciated, bleed holes 52a-d may be placed along any surfaces 24-30. As best shown by FIG.3, drop gate 22 includes depressions 32, latches 54a-54b, fill holes 56a, 56b and bleed holes 58a, 58b, 58c, 58d. Depressions 32 provide structural strength for drop gate 22. However, depressions 32 also partially interrupt hollow interior 32. Latches 54a-54b

are mounted within side wall 22 and permit side wall 22 to be releasably latched to drop gate wall 20. Latches 54a-54b are inset within outer surface 30 of drop gate 22. As a result, latches 54a-54b further interrupt hollow interior 32 of drop gate 22. Fill holes 56a and 56b are positioned along top surface 24 and communicate between top surface 24 and hollow interior 32. Fill holes 56a and 56b permit insulating foam to be injected into hollow interior 32 to insulate drop gate 22. As can be appreciated, fill holes 56 may be placed along any surface 24-30 of pallet sized member, drop gate 22. Bleed holes 58a-58d are generally elongated, narrow slits extending surfaces 24 and 30 to communicate with hollow interior 32. Bleed holes 58a and 58b are positioned along top surface 24 on opposite ends of fill holes 56a and 56b. Bleed hole 58c is located below latch 54b. Bleed 58c allows gas to escape and indicates when hollow interior 32 below latch 54b is filled with insulating foam. Bleed hole 58d is located below latch 54a. Bleed hole 58d allows gas to escape and indicates when hollow interior 32 below latch 54a is filled with insulating foam. Fill holes 56 and bleed holes 58 permit drop gate 22 to be more completely filled with insulating foam. As a result, drop gate 22 better insulates temperature sensitive goods contained within container 10. FIG.4 illustrates insulating system 70 for insulating pallet sized members such as side wall 18, drop gate wall 20 and drop gate 22. System 70 includes jig 72, plugs 74 and foam injector 76. Jig 72 holds each pallet sized member while each pallet sized member is filled under pressure with insulating foam. Jig 72 includes bottom outer frame 78, top outer frame 80 and cross beams 82a-82b. Bottom outer frame 78 and top outer frame 80 are identical. Outer frames 78 and 80 each include struts 84a and 84b, respectively. Struts 84 comprise elongated thin beams formed of wood. Alternatively, struts 84 may be made of a variety of materials including

plastics or metals. Struts 84 are joined together on their ends by end members 86. End members 86 hold struts 84 at a fixed distance apart from one another. Consequently, struts 84 are prevented from bowing outward as forces are applied against struts 84. Bottom outer frame 78 and top outer frame 80 are joined together by cross beams 82.

Cross beams 82a and 82b are generally thicker than struts 84 so as to extend outward from struts 84. Each cross beam 82 includes an upper notch 88 and a lower notch 90. Upper notch 88 is sized to receive strut 84 of top outer frame 80 while notch 90 is sized to receive strut 84 of bottom outer frame 78. Bottom outer frame 78, top outer frame 80 and cross beams 82 are assembled together so as to preferably form five individual frame compartments 92a-92d. Each frame compartment 92 has a length and a width large enough to receive one of frame members 18-22. For example, compartment 92a receives a pallet sized member (shown with dashed lines). The pallet sized member may be any one of members 18-22. The member is positioned between cross beams 82 so that cross beams 82 abut both rear surface 28 and front surface 30 of the pallet member. Consequently, the pallet member is securely held within compartment 92a. Jig 72 preferably holds the pallet sized members while the pallet sized members are filled with insulating foam. Jig 72 may also be used to hold pallet sized members while fill holes are created within the pallet sized members. Because cross beams 82 abut the surfaces of each pallet sized member, cross beams 82 prevent the surfaces of the pallet sized members from deflecting or bowing outward while each pallet sized member is filled with insulating foam. Because each pallet sized member has a large hollow interior which must be filled with insulating foam, and because each pallet sized member includes depressions which interrupt the hollow interior of each member, the insulating foam must be injected under high pressure to

completely fill the hollow interior of each member. Cross beams 82a and 82b of jig 72 prevent the inner wall or surface 28 and the outer wall or surface 30 from deflecting under this pressure. Because the pallet sized members do not bow outward or deflect while being filled with insulating foam, each pallet sized member achieves tolerance specifications so that container 10 is more easily assembled to meet size specifications.

Plugs 74 partially fit within the fill holes of the pallet sized member (shown by dashed lines) and include stopper 94 and handle 96. Stopper 94 is sized to partially fit within the fill hole so that the fill hole is sealed. Stopper 94 has a cylindrical hollow lower portion extending from a rim which encircles an upper end of the cylindrical portion. Stopper 94 is preferably formed from a rubber or plastic material.

Handle 96 is an elongated cylindrical tube press fit to stopper 94. Preferably, handle 96 comprises a wooden dowel press fit within the hollow interior of stopper 94. Handle 96 permits quick insertion and removal of plug 74 within the fill holes. Plug 94 prevents insulating foam from expanding or flowing out of the plug filled fill hole. At the same time, plug 74 plugs the fill hole to force the insulating foam to expand in other directions so that the hollow interior of the pallet sized member is more completely filled. As a result, the pallet sized member better insulates goods within container 10.

Foam injector 76 comprises a standard pair of tanks capable of injecting insulating foam under pressure as is conventionally known in the art. Foam injector 76 preferably discharges insulating foam under about 150 lbs. of pressure. The insulating foam preferably is 1.75 lb. polyurethane. Foam injector 76 preferably has an output end 98 for directing the insulating foam under pressure through the fill holes of each pallet sized member.

FIG. 5 shows a flow chart of a method 100 for insulating one of pallet sized members 16-22. Alternatively, method 100 may be used to insulate any pallet sized member having a hollow interior. As illustrated by block 102, one of pallet sized members 16-22 is positioned within one of compartments 92 of jig 72. Jig 72 holds and supports the pallet sized member and prevents the surfaces of the pallet sized member from deformation while the pallet sized member is filled with foam.

As indicated by block 104, fill holes are created within the pallet sized member. Fill holes are preferably created or formed while pallet sized member is positioned within jig 72. As a result, the pallet sized member is held steady by jig 72. Fill holes are preferably created by drilling into the pallet sized member. Alternatively, the fill holes may be formed as part of the pallet sized member while the member is being blow molded. The fill holes preferably have a diameter of about 1/2 inch. As can be appreciated, the fill holes may also be created before the pallet sized member is positioned within jig 72. The fill holes are preferably spaced apart along the top surface of the pallet sized member so that the entire hollow interior of the pallet sized member is filled with insulating foam. The number of fill holes and the positions of the fill holes depends upon the size of the pallet sized member and pressure at which foam is injected into the pallet sized member.

As indicated by block 106, bleed holes are also created within the pallet sized member. The bleed holes are preferably formed by cutting into surfaces of the pallet sized member so that slits are formed. The bleed holes preferably have a thickness of about 1/8 of an inch. The bleed holes permit air and gasses to be exhausted from the hollow interior of the pallet sized member. As a result, the bleed holes prevent the formation of air pockets within the insulating foam. In addition, the bleed holes indicate to

an operator when specific portions of the pallet sized member have been completely filled with insulating foam. As a result, the hollow interior of the pallet sized member is more completely filled with insulating foam, thereby allowing pallet sized member to better insulate contents of the pallet sized container.

Block 108 indicates that the fill holes are plugged by plug 74. Typically, every fill hole but one is plugged. Plugging the fill holes prevents the injected insulating foam from discharging out of the fill holes. Plugging the fill holes also forces the insulating foam to expand and flow in other directions, thereby filling hard-to-reach portions of the hollow interior of the pallet sized member. Consequently, the pallet sized member exhibits a higher fill percentage which improves the insulation effect of the pallet sized member.

As indicated by block 110, insulating foam is injected through an unplugged fill hole into the hollow interior of the pallet sized member. The insulating foam is preferably injected under pressure of about 150 lbs. As can be appreciated, the pressure depends upon the size of the pallet sized member, the position and number of fill holes, and the shape of the pallet sized member. The insulating foam preferably is injected until all portions of the hollow interior are filled as indicated by the bleed holes. The insulating foam preferably comprises 1.75 lb. polyurethane.

As shown by block 112, the fill hole in which foam was injected through is then plugged by plug 74. Plugging the remaining fill hole prevents the insulating foam from further expanding or flowing out of the fill hole. Plugging the remaining fill hole also forces the insulating foam to flow and expand into other portions of the hollow interior. Thus, the hollow interior is more completely filled with insulating foam. The above method results in the hollow interior of each pallet sized member 16-22 being filled

with insulating foam from between about 90 percent to about 99 percent. Because the above-method achieves this high fill percentage, pallet sized containers can more effectively insulate and protect large wholesale quantities of temperature sensitive goods.

Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.