US2717114A

US2717114A - Thermal container

Info

Publication number: US2717114A
Application number: US158469A
Authority: US
Inventors: Jr Charles L Parham
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-04-27
Filing date: 1950-04-27
Publication date: 1955-09-06
Anticipated expiration: 1972-09-06

Description

Sept. 6, 1955 Filed April 27, 1950 6 Sheets-Sheet l I i l I l I I I I I I I l I I I I I I I I I I I I .v44 I I i I I I r:' 2:;I I 1 I INVENTOR.

ATTORNR? 6 Sheets-Sheet 2 THERMAL CONTAINER l l I c. 1.. PARHAM,

Sept. 6, 1955 Filed April 27, 1950 ATTOR Sept. 6, 1955 c. L. PARHAM, JR 2,

THERMAL CONTAINER Filed April 27, 1950 a Sheets-Sheet 5 I4 28 l3 I5 I 1 258 i {L i 30 I I INVENTOR.

CHARLES L.PARHAM Jr. 22

Sept.

Filed April 27, 1950 c. L. PARHAM, JR 2,717,114

THERMAL CONTAINER 6 Sheets-Sheet 4 IOO F|G.IO.

INVENTOR.

CHARLES L.PARHAM Jr,

Sept. 6, 1955 c. L. PARHAM, JR 1 2,717,114

THERMAL CONTAINER Filed April 27, 1950 6 Sheets-Sheet 5 FIG.I4.

INVENTOR. CHARLES L. PARHAM Jr.

ATTORN S Sept. 6, 1955 c. L. PARHAM, JR 2,

THERMAL CONTAINER Filed April 27, 1950 6 Sheets-Sheet s INVENTOR.

CHARLES L.PARHAM Jr- ATTORN 4 3 3 2 4 I I f .lullll lllufwnwll llllrllll United States Patent THERMAL CONTAINER Charies L. Parham, Jr., Dear-born, Mich. Application April 27, 1950, Serial No. 158,469

9 Claims. (Cl. 229-14) The present invention relates to a thermal container, and more particularly to one comprising an outer insulated box and a removable inner box for carrying food or the like.

It is an object of the present invention to provide a thermal container characterized by the economy with which it may be manufactured and sold, its utility and thermal efiiciency, and its adaptability to many different uses.

More specifically, it is an object of the present invention to provide a thermal container comprising an outer insulated box formed principally of cardboard or the like, including separate insulation for each side and insulation for the bottom, the box being designed to provide ledge portions overlying the upper edges of the side insulation and liner portions overlying at least the upper portion of the inner surfaces of the side insulation.

it is a further object of the present invention to provide a thermal container of the type referred to above in which the inner liner portions extend substantially to the bottom of the box and are retained in place by a bottom insulation.

It is a further object of the present invention to provide a thermal container of the type referred to in which wall forming portions are provided with interlocking elements such as cooperating notches and flanges;

It is a further object of the present invention to provide an inner box structure having inwardly extending resilient flanges at the tops and the sides thereof, and a cover hinged to the top rear adapted to be retained in closed position in substantial sealing contact with the aforementioned flanges.

It is a further object of the present invention to provide a thermal container of cardboard or similar material having hand holes in the ends characterized by, the provision of a doubled edge of material at the upper sides of the holes to reinforce the holes and to provide greater area of contact with the hand of the user. a

It is a further object of the present invention to provide an insulated container having hand holes formed through the end walls, insulating material disposed inwardly from the hand holes, and movable or stationary guards overlying the hand holes and normally disposed against the inner surface of the hand holes, the guards being movable inwardly to permit insertion of the fingers of the user while preventing contact between the fingers of the user and the insulating material.

It is a further object of the present invention to provide a guard as referred to above, in the form of a panel shaped to fit closely between the bottom and side walls so as to give added strength and rigidity to the container.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a perspective view of the complete thermal container with the top open.

Figure 2 is a top plan view of the thermal container. Figure 3 is 'a plan view of the outer box in open position.

Figure section on the line 44, Figure 2. .Figure section on the line 55, Figure 4. Figure section on the line 6-6, Figure 4. Figure 7 is a perspective view of the inner box in partially open condition. I

1 Figures 8 and 9 are plan views of the two elements making up the inner box, in open condition.

Figure 10 is a perspective view of a second embodiment of the invention.

Figure 11 is a plan view of the outer container 'after die cutting and before assembly.

Figure 12 is a plan view of the end guard plates employed in the outer container.

Figure 13 is a perspective view showing the inner container in partly assembled relation.

Figure 14 is a plan view of one of the component parts of the inner container.

Figure 15 is a plan view of the other component part of the inner container.

Figure 16 is a plan view of the structure shown in Figure 10 with the top closed.

Figure 17 is a section onthe line 17-17, Figure 16.

Figure 18 is a section on the line 1818, Figure 16. Figure 19 is a section on the line 1919, Figure 17.

Figure 20 is a fragmentary end elevation with parts broken away showing hand holes for lifting the as-' sembly.

The outer box and inner containerdisclosed herein may conveniently be formed of cardboard but it is within the contemplation of the present invention that the material from which these boxes and containers are formed 4isa Sisa 6isa may be other fibrous material, plastic, wood or metal.

Where the material 'of the box is referred to hereinafter as cardboard it will be understood that this description is exemplary and not limiting.

. Referring now to the drawings the thermal container comprises a pair of independent and separable box sections. As best seen in Figure 1, there is an outer insulated box10 which is open at its top, and an inner removable container indicated generally at 12. The inner container is provided at the front with a rearwardly extending flap 13 and at the sides with inwardly extending

flaps

14 and 15. The container 12 includes a top section 16 with a downwardly extending flap 17 which in use will be inserted in the space between the front wall of the outer box 10 and the front wall of the inner container 12.

The inner container 12 may be formed of one or more component parts but as seen in Figures 7, 8, and 9, is formed from two pieces of cardboard or other suitable material, the two pieces being cut to the shape illustrated in Figures 8 and 9. The bottom rear and top of the box are formed from a piece indicated generally at 20 as shown in Figure 9, comprising the top portion 16 previously referred to, the flap 17 previously referred to, a back portion 21 and a bottom portion 22. The separate portions are divided by score marks or creases to facilitate folding. The remainder of the container is made up of a piece indicated generally at 25 as shown in Figure 8, and comprises a left side portion 26 having at one side the top flap 14 previously referred to, andhaving at the opposite side a bottom flap 27. The part 25 also includes the front portion 28 having at one side thereof the top flap 13 previously referred to, and having at the opposite side thereof a bottom flap 29. The part 25 also includes the right side portion 30 having at one side the top flap 15 previously referred to and having at the other side thereof a bottom flap 31. Intermediate the

side portions

26 and 30 and the front portion 28 the flaps are provided with -notches to permit interfitting in the manner illustrated in Figures 1 and 7.

To assemble the container 12 the parts are folded as above described and the rear edges of the

side portions

26 and 30 are secured to the side edges of the back portion 21 by any suitable means, such for example as adhesive paper or cloth strips 32. It is found unnecessary to provide any permanent attaching means for retaining the bottom portion 22 in proper relationship. Instead, this portion will be folded up so as to rest against the upper surfaces of the inturned bottom flaps 27, 2?, and 31. Since the edges of the bottom portion 22 rests against the portion of these flaps which is respectively adjacent the left side front and right side walls of the container, the bottom portion 22 will be adequately supported in position.

The outer box 10 which provides and helps provide for the insulation for the assembly, is formed primarily from a single piece of cardboard or other suitable material, and this material is initially precut to the shape best illustrated in Figure 3. The piece 40 is subdivided into a number of portions which will be specifically referred to and each of these portions is separated from adjacent portions either by a cut or space which will be indicated in full lines, or by a crease or score line to facilitate folding, which is indicated in this figure by dotted lines. The part 40 comprises an end portion 41 having a hand opening fiap 42 provided therein of special construction which will be subsequently described in detail. At one side of the end portion 41 is a partial bottom flap 43. At the opposite side of the end portion 41 is a ledge portion 44 which is adapted to overlie and protect insulating material as will subsequently be described. Extending outwardly from the ledge portion 44 is an inner end liner portion 45. Adjacent the end portion 41 is a first side portion 46 having at one side thereof a partial bottom flap 47, and at the opposite side thereof a narrow ledge portion 48, beyond which is provided an inner side liner portion 49. Adjacent the side portion 46 is a second end portion 50 provided with a hand opening flap 51 similar in all respects to the hand opening flap 42. At one side of the end portion 50 is a partial bottom flap 52, and at the-opposite side of the end portion 50 is a narrow ledge portion 53, beyond which is provided a second inner end liner portion 54. Beyond the end portion 50 is a second side portion 55 having a partial bottom flap 56 extending from one side thereof, a narrow ledge portion 57 at the opposite side thereof, and an inner side liner portion 58 extending beyond the ledge portion 57. Beyond the side portion 55 is a narrow attaching flange 60 which in assembly is stapled, clipped, or otherwise secured to the free edge of the end portion 41, suitable securing means for this purpose being illustrated in Figure l at 62.

The box 19 is designed to have insulation located to overlie its bottom and extend around all four sides of the box. The insulation is preferably formed of an insulating material, either loose fill, flexible, semi-rigid or rigid batt or blanket such for example as glass wool, mineral wool, corkboard, Styrofoam, vegetable fibres or the like and are precut into rectangular sections of the proper size to fit into the box during assembly as will now be described. Loose fill insulations may be hand packed or pneumatically applied, or installed.

in order to assemble the box 10 the part 40 is initially folded along the

creases

63, 64, and (Figure 3) to bring the attaching flange 60 into proper position adjacent the free edge of the end portion 41. The fiange 60 will be located inside the enclosure thus produced at the juncture between the end portion 41 and the side portion 55 and may be permanently attached thereto as by rivets, staples or the like. At this time the bottom

partial flaps

43, 47, 52, and 56 may be bent upwardly to provide a bottom surface for the box iii and may be retained in folded relationship by suitable means such for example as staples, adhesive strips or the like.

The next step in the assembly of the box 10 is to position the side insulation and 71 in position against the

side portions

46 and 55. Thereafter, the inner

side liner portions

49 and 58 are folded inwardly to overlie the insulation 70 and 71 respectively, and during this operation the

ledge portions

48 and 57 fall into position overlying the tops of the insulation 70 and 71.

The next step in the assembly is to position the end insulation 75 and 76 in position at the end of the box. The insulation is cut, or packed to a size such that it fits snugly within the confronting surface of the inner

side liner portions

49 and 58, and thus retains these portions in assembled relation. it will be observed that the end

inner liner portions

45 and 54 are of somewhat less width than the corresponding

outer end portions

41 and 50.

This is to permit the inner

end liner portions

45 and 54 to fit within the box between the

inner side portions

49 and 58 thus acting as an inner lock. The inner

end liner portions

45 and 54 are next bent inwardly of the box so that they overlie the end insulation 75 and 76, as best seen in Figure 4. In this figure it will be observed that bending the inner end liner portion 45 into position over the insulation 75 results in positioning the ledge portion 44 over the upper end of the insulation 75. In the same way, when the innerend liner portion 54 is bent into the position shown in Figure 4 it results in positioning the ledge portion 53 in overlying relationship to the insulation 76.

With the parts in the condition of assembly so far described the box is provided with insulation at both ends and both sides, which insulation is completely concealed and covered by the respective ledge portions and liner portions described in detail.

The next step in the assembly of the box is to position a bottom insulation portion 73 at the bottom of the box intermediate the

liner portions

45, 49, 54, and 58. This insulation will serve to retain the liner portions in assembled position parallel to the respective

outer wall portions

41, 46, 50, and 55. Thereafter, the container 12 may be inserted in position to overlie the bottom insulation 7 S and the device is ready for use.

In the foregoing description passing reference was made to the hand opening flaps 42 and 51 provided in the outer end portions of the box 10. Referring now more particularly to Figures 4 and 6, a preferred construction of the hand opening flaps is illustrated and described. The

flaps

42 and 51 are not cut completely through but instead are cut along three sides as indicated in Figure 3 and the partially severed portion is creased along the dotted

lines

80 and 81. In order to protect the user from contact with the insulating material while lifting the assembly, it is preferred to provide inner insulation covers 83. These elements may be generally rectangular pieces of cardboard or other material provided with a bent flange 84 along one side, the relationship being such that the flange 84 overlies the top of one of the insulations 75 or 76 and the remainder of the cover 83 extends downwardly in a position to overlie the opening 85 provided by bending the hand opening flap 51 upwardly. Pref erably, the covers 83 are provided with struck-out portions 86 which may be reversely bent as seen in Figure 4 to interfit over the upwardly extending edges of the reversely bent hand opening flaps 51 or 42. Due to the compressible nature of the insulating material, covers 83 may be displaced inwardly to permit entry of fingers into the hand openings in lifting the structure while preventing contact between the fingers and the insulating ma terial. This arrangement offers several advantages. In the first place it strengthens the material around the opening 85 since its upper edge is thus presented as a folded portion. In the second place it provides a thicker edge at the top of the opening 85 to be gripped by the fingers. It also results in providing a deep recess into which the fingers of the user may be inserted. Most important, it provides a cover over the insulating material. The

In actual use the box and container may be made of widely different materials. An entirely satisfactory construction results from the use of cardboard which may have its surface treated to render it wear resistant and to improve its appearance. Preferably, the inner container is waterproofed and any one of several expedients may be adopted for this purpose. Thus for example, the inner container 12 may be lined with a multiple ply foil or polyethylene or a metal foil such as aluminum laminated with polyethylene. Obviously, the gauge of the waterproofing lining will be determined by the use for which the container is intended.

Alternatively, the inner container may be spray coated on its inside with a suitable material such for example as plastic in order to render it water-proof, water repellant or water resistant.

The construction described is primarily useful as an insulating container and it may be used for either hot or cold material. In the event that it is used to transport and store chilled material no further insulation will be required inasmuch as it is adequately insulated around the sides and bottom and is sufiiciently tightly closed at the top to prevent setting up eddy currents which would reduce the thermal efliciency. If the structure is intended for use with hot contents it may in some cases be desirable to provide additional insulation at the top.

While the

inner liner portions

45, 49, 54, and 58 have been disclosed as dimensioned to extend completely to the bottom of the box, it will be appreciated that this will not in all cases be necessary. The essential requirement is that the inner liner portions be of sufiicient length to be interlocked in place when the inner container 12 is inserted in the insulated box.

It is also within the contemplation of the present invention to provide a transverse partition across the inner container 12, a portion of such partition being indicated at 90 in Figure 1. Such a partition may also be provided by a pair of cardboard partition elements spaced apart and receiving between them a suitable insulating material. With this construction the box may be used simultaneously for storing and transporting both hot and cold materials, these materials being separated in use by the insulated partition 90.

The present construction is highly useful in rapid transit as by air transport, of frozen articles such for example as sea food. It has been found that the thermal efficiency of the construction is such that prefrozen sea food may be transported without refrigeration enroute from ocean ports to destinations located centrally within the United States with the loss of but a few degrees in temperature. The apparatus is particularly useful for this purpose since It is extremely light, yet rugged enough to withstand repeated use.

This leads to an additional advantage of the present construction. Since the outer box and inner container may both be quickly assembled and disassembled, it is possible to provide for temporary securing of the box and container in assembled relation by the use of securing means such for example as adhesive tape or the like. Alternatively, the boxes may be assembled with removable staples, clips, rivets or the like. After the box has been employed in air shipment for example, it may be disassembled and returned to its original destination in flat condition. This is an important feature of the present invention since the volume to weight ratio of the assembled box and container is relatively large. By disassembling the box and container and returning them, together with the insulation packed in flat relationship, a much smaller volume to weight ratio may be obtained 1 sides with insulation.

and accordingly, many more of the boxes and containers may be returned in disassembled relation than would otherwise be the case.

Referring now to Figures 10 through 20 there is illustrated a second embodiment of the present invention which in many respects offers advantages over the first embodiment previously described.

In general, the embodiment of the invention illustrated in Figures 10 through 20 is designed to facilitate collapse of the box so that after use in shipping thermally insulated material, it may be collapsed to flat condition and returned for re-use, with a great saving of space. In this embodiment of the invention this is accomplished without disconnecting any elements of the inner or outer box. Instead the inner box, which may be formed of one or more parts and which is illustrated as comprising two component parts, is collapsed to flat condition. The outer box is also collapsed to flat condition, the side walls of the box as illustrated being thus folded double so as to provide a flat assembly whose major dimension is approximately equal to the combined length and width of the outer box.

As seen in Figure 10 the outer box receives the inner box 200 and surrounds it at the bottom and four The inner box is provided with a cover portion which seals the top opening into the box. If circumstances require a separate top insulation may be provided or this insulation may be carried by the cover of the inner box.

The outer box 100 is formed of a single piece of sheet material such for example as cardboard which is die cut and scored as indicated in Figure 11. In this figure die cut lines are indicated as full lines and score lines are indicated as broken lines. The box 100 comprises a front wall 101, an end wall 102, a rear wall 103, and a second end wall 104.

End walls

102 and 104 are provided with partial cutout flaps 105 to constitute handle holes as will later be described. The frontwall 101 has a side flange 106 which is permanently secured to the edge of the end wall 104 by suitable means such for example as the staples indicated at 107 in Figure 10. t

The bottom of the outerbox 100 is formed by separated bottom flaps 108 carried by the end wall 104 and similar separated bottom flaps 109 carried by the end wall 102. When the front, rear, and end walls are folded around and the flap 106 stapled to the end wall 104, a rectangular enclosure is made. Thereafter the bottom flaps 108 and 109 are folded up to occupy the plane of the bottom of the box. The front wall 101 is provided with a bottom wall portion 110 scored as indicated at 111, to form a lower bottom portion 112 and an upper bottom portion 113 adapted to retain the box bottom assembled as will subsequently be described. In like manner the rear wall 103 has a bottom forming portion 114 scored as indicated at 115 to provide a lower bottom portion 116 and an upper or inner bottom portion 117.

Referring now to Figure 18 the manner in which the bottom Wall portions cooperate will be described. The bottom flaps 108 and 109 are bent up into the plane of the bottom of the box. The slots 118 between the

flaps

108 and 109, thereupon become aligned and provide a space into which the

bottom portions

113 and 117 may be in serted and folded backas well illustrated in Figure 18 This arrangement provides a strong interlock which retains the bottom of the box in assembled relation without the necessity of employing fastening elements.

As in the foregoing embodiment of the invention, the outer box is designed to provide insulation at the bottom as well as insulation at the four sides of the box, this latter insulation being overlaid and protected by inner walls. Moreover, the box construction is such that the box has portions overlying the space between its inner and outer walls, thus protecting the insulation and preventing-escape thereof. This construction is provided by the parts best illustrated in Figure 11. The box front 101 carries a front ledge 120 which is die cut as illustrated in the figure, and which includes rearwardly extending projections 122. The inner edge of the ledge 120 is defined by a scored line 124 which may be substantially straight throughout its major portion but which includes inclined portions 125 adjacent its corners for a purpose subsequently to be described. Beyond the scored line 124 is a front liner wall 126 including laterally extending

flanges

127 and 128.

The rear wall 103 is provided with ledge and liner portions substantially identical with those provided at the front wall. Thus, ledge portion 130 is provided terminating in the scored line 132 including inclined end portions 133 and also including forwardly extending projections 134. Beyond the scored line 133 is the rear liner wall 135 provided with forwardly extending

flanges

136 and 137.

The end wall 102 is provided with a ledge portion 140 defined by

straight score lines

141 and 142 and straight beveled die cut ends 143. Beyond the score line 142 is the end liner wall 144. a In like manner the outer end wall 104 carries a ledge portion 145 defined between two

straight score lines

146 and 147 and defined by straight beveled ends 148. Beyond the score line 147 is the end liner wall 150.

The flaps 105 previously referred to as forming hand holes for lifting the box, may as illustrated be provided in the ends of the box or if preferred could be provided in the front and back of the box. Preferably, the flaps 105 are scored along their upper edge and in use are bent inwardly and upwardly to the position best illustrated in Figure 17, thus leaving a hand hole 152. This has the effect of reinforcing the upper edge of the hand hole. If desired, the hand hole may be further reinforced and protected by means of rubber, plastic, or

other type shields.

In some cases the insulating material employed may be glass wool, mineral wool, or other material. In order to protect the users hand from coming in contact with the insulation, both to protect his hand and to protect the insulation, and more particularly to prevent the insulation working out of the hand hole 152, the guard plates 154 are provided. These plates are preferably formed of the same material as the box and are generally rectangular in shape and provided with a score line 156 dividing the guard into a main portion 158 and flange portion 160. The guard plate 154 in use is inserted into the box with its rebent flange 160 located behind the upwardly bent flap 105. thus assisting in retaining the flap in place and preventing the fingers of the user from coming in contact with insulation material. The guard 154 has an additional function of considerable importance. Its main portion 158 is of a size to fit closely between the front wall 101 and the rear wall 103 as best seen in Figure 19, and thus will serve to strengthen and reinforce the entire box structure. 1

Due to the compressibility of the insulation, portion 158 of the plates is movable inwardly to permit entry of fingers into holes 152 while preventing contact between the fingers and the insulating material.

In assembling the outer box the first operation is to fold the side walls of the box into rectangular formation and to staple the flap 1126 to the edge of the end wall 104. Thereafter, flaps 108 and 109 are bent up and the

bottom forming portions

110 and 114 are brought into position with the

portions

113 and 117 thereof first extended through the slot 118 and then folded outwardly to overlie the

portions

112 and 116 respectively.

If desired, the width of the

portions

113 and 117 may be slightly greater than the width of the

portions

112 and 116 so that the free edges of the portions 113 and 117' may frictionally engage the inner surfaces of the front wall 101 and the rear wall 103 respectively, thus retaining the

parts

113 and 117 in position.

Thereafter, end insulation 162 and front and back insulation 164 is introduced into the box and the liner portions are folded inwardly to position the ledge portions over the upper edge of the insulation. In this operation the front and

rear liner walls

126 and 135 are first folded into place with the

flanges

127, 128, 136 and 137 bent inwardly to overlie portions of the insulation at the ends of the box. Thereafter the

end liner walls

144 and 150 are moved into place. Due to the inclined portions and 133 of the scores,

end liner walls

144 and 150 will wedge as they come into fully operative position, and are thereby retained in position. As the front and rear liner walls 126 and are moved into position the

ledge portions

120 and 130 assume the overlying position illustrated in Figure 18, and the

projections

122 and 134 thereon overlie portions at the ends of the end insulation 162. As the

end liner walls

144 and 150 are moved into position the ledge portions and assume the overlying position illustrated in Figure 17 and these ledge portions overlie the

projections

122 and 134 as best illustrated in Figure 16.

Finally, the bottom insulation 166 is placed overlying the bottom of the box and will further tend to retain the

liner walls

126, 144, 135, and in position. Normally, the inner container rests directly against the bottom insulation 1.66 but if preferred, a separate panel may be provided to overlie the insulation and if desired, this panel could be formed as an integrally extending part on one of the

liner Walls

126 or 135. A fragment of such wall is indicated at 168 and it will be understood that if employed this wall will be of a size to cover the bottom insulation 166 and to extend between front and

rear liner walls

126 and 135 and end

liner walls

144 and 150.

As previously described, the insulation employed may be any suitable material, either loose fill, or cut pieces of fragile flexible blankets, or relatively strong selfsupporting material. It is also within the contemplation of the present invention to provide this insulation as permanently assembled to the appropriate surfaces of the box 100. Thus for example, insulation may be adhered or otherwise secured to the

Walls

101, 102, 103, and 104, or alternatively, to the appropriate surfaces of the

liner walls

126, 144, 135, and 15%. Moreover, if a bottom liner wall such as suggested and indicated at 168 is employed, the bottom insulation may be permanently secured to the appropriate surface of such wall. If employed as permanently attached to the appropriate wall surfaces of the box, the insulation will be fully protected when the box is collapsed for shipment since it will in all cases be enclosed between protecting walls of the box in collapsed condition.

Referring now to Figures l3, l4, and 15, a preferred construction of the inner container 200 is illustrated. Essentially, the container 2:30 comprises a rectangular box having a hinged lid associated therewith. Referring in detail to Figures 14 and 15, component parts of the box are illustrated. In these figures the box is shown as composed of two component parts adapted to be separated for return shipment, and adapted to form an adequately self-supporting box when in use without the necessity of permanent or removable fastening devices such as staples, tape or the like. In Figure 14 there is illustrated a die cut sheet material comprising a front wall 202 and end

walls

203 and 204. The front wall 202 has a top flap 29S and a bottom flap 206. The end wall 263 has a top flap 207 and a bottom flap 208. The end wall 204 has a top flap 209 and a bottom flap 210. The end wall 203 has an interlocking flange 211 and end wall 204 has a similar interlocking flange 212. The material is die cut to the shape illustrated and is scored for folding along the dotted lines as shown.

Associated with the part illustrated in Figure 14 is the structure illustrated in Figure 15. This comprises a bottom wall 214, a rear wall 215, and a top closure or cover 216. The rear wall 215 is provided at opposite ends there- 9 of with notches 217 which receive the interlocking

flanges

211 and 212 as best illustrated in Figure 13. The cover 216 has a front flap or flange 218 and side flaps or flanges 219. Finger holes as indicated at 220 are provided for assisting the user in raising the lid 216.

The container 200 is not intended to be self-supporting independently of the outer box 100, but when assembled together and placed in the box or when assembled in the box, it is self-supporting. In assembling the container structure 200 in the box 100 the portion illustrated in Figure 14 may first be placed in the box in proper position so that the front wall 202 extends along the front liner wall 126 and the

side walls

203 and 204 extend along the

liner walls

144 and 150 respectively. At this time the

bottom flanges

206, 208, and 210 will extend inwardly and the

top flanges

205, 207, and 209 will also extend inwardly. Thereafter, the component illustrated in Figure 15 may be inserted, pressing the bottom wall 214 downwardly into position and the rear wall 215 rearwardly toward the box liner portion 126. When the wall 215' reaches proper position the interlocking

flanges

211 and 212 will engage in the notches 217, thus retaining the parts in firmly assembled relation.

In use the inwardly extending

flanges

207, 205 and 209 of the box afford a substantial seal and the

flanges

218 and 219 on the cover 216 cooperate to produce a very effective sealing means. The side flanges 219 extend downwardly outside of the

end walls

203 and 204 of the container and between these Walls and the inner lining walls of the box 100. In the same Way the front flap or flange 218 is inserted outside of the front wall 202 of the box and extends down between this wall and the front liner wall 126.

Certain obvious modifications of the foregoing specifically described structure will suggest themselves. Thus for example, the ledge which overlies the interposed layer of insulation may be a part of the inner removable box instead of the outer box. In this case, as will be apparent, the cover for the inner removable box will be separate from the box. In the simplest case the outer box will comprise a bottom and four sides. The inner box will comprise a bottom and four sides and along the upper edge of each side of the inner box will be provided a ledge portion shaped to overlie the upper edge of the insulation provided between the side walls of the inner and outer boxes. At the outer edges of these ledge portions there will be provided flaps adapted to extend downwardly between the outside of the insulation and the inside surfaces of the outer box.

The boxes are capable of many uses and due to their inexpensive construction may be used in many cases where more expensive thermal containers would not be practical. They are particularly useful as a picnic box for families. Their use "J1 transporting frozen or chilled foods has previously been referred to. They may also be employed in machinery assembly plants for retaining chilled parts at a low temperature while awaiting assembly, in situations where closely fitting parts are shrunk by chilling to enable them to fit parts having extremely close tolerances therewith.

The drawings and the foregoing specification constitute a description of the improved thermal container in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

l. A thermal container comprising an open topped outer box having a bottom, outer sides, inwardly extending ledge portions at the top edges of all sides, and inner liner portions at the inner edges of said ledge portions, side insulation received between the sides and inner liner portions, and bottom insulation overlying said bottom, an inner box removably received in said outer box and having flexible inwardly extending flanges at the top of the sides and front, a cover hinged to the 10 top edge of the back, and a flap on the front end of said cover insertable between the outside of the inner box and the inside of the front wall of the outer box.

2. A collapsible insulated box structure comprising an open topped outer box having spaced apart inner and outer front, rear and side walls and a bottom wall, .insulating material disposed between said inner and outer walls, insulating material covering the bottom wall of said outer box, a removable two-piece inner box adapted to be assembled in place in said inner box, said inner box comprising a first sheet element cut and scored to define a bottom wall to overlie the insulation covering the bottom wall of said outer box, a rear wall, and a cover, said inner box also comprising a second sheet element cut and scored to define a front wall and a pair of opposed end walls, the vertical edges of the end walls on said second element and the adjacent vertical edges on the rear wall of said first element having interfitting notches and flanges preventing relative vertical movement therebetween and retaining said inner box in assembly while it remains in said outer box.

3. Structure as defined in claim 2 in which the cover of said inner box includes a flap at its forward edge insertable into the space between the front wall of said inner box and the inner front wall of said outer box.

4. Thermal container structure comprising inner and outer boxes separable and collapsible for storage and shipment in flat condition, and insulation material in the form of self-supporting blankets, said outer box comprising a sheet element cut and scored to provide a bottom wall, four outer side walls, ledges extending inwardly from the top edges of said side walls, and liner walls extending downwardly from the inner edges of said ledges, said insulating blankets comprising separate side and bottom blankets disposed respectively between said side and liner walls and overlying said bottom wall, a removable and collapsible inner box having a bottom wall adapted to overlie and rest upon the bottom blanket, one of said bottom blanket and inner box being effective to retain said liner walls in position in assembly.

5. Structure as defined in claim 4 in which said liner walls extend substantially to the bottom of said outer box and said bottom blanket abuts the lower edge portions of said liner walls to retain them in parallelism with said outer side walls prior to insertion of said inner box into said outer box.

6. Structure as defined in claim 4 in which said insulation comprises four separate side blankets, a first pair of opposed side blankets being dimensioned to extend between and contact at their ends the inner surfaces of an opposed pair of outer side walls, the remaining pair of side blankets being dimensioned to extend between and contact at their ends the inner surfaces of the first pair of side blankets to retain said side blankets in assembly prior to folding over said ledge and liner walls.

7. A thermally insulated shipping container adapted to be knocked down for return shipment or storage in flat condition comprising: a one-piece outer, open topped box having a bottom, front, rear and two side wall portions, ledge portions extending inwardly from the top edges of said front, rear and side wall portions, liner portions extending downwardly from the inner edges of said ledge portions; an inner box structure comprising a first element having a bottom wall portion, a rear wall portion extending upwardly from said bottom wall portion, a cover portion extending forwardly from the top of said rear wall portion, and a flap portion at the front edge of said cover portion, and a second element having connected front and side wall portions, the rear edges of the side wall portions of said second element and the side edges of the rear wall portion of said first element having releasably engaging interlock means thereon; and insula tion material interposed between the bottom wall portions of said outer and inner box and between the front, rear and side wall portions of said outer and inner box, said insulation material comprising relatively strong self-supporting blankets shaped to fit within the spaces between the bottom, front, rear and side wall portions of the boxes.

8. A container as defined in claim 7 in which the bottom edges of said liner portions lie closely adjacent the bottom wall portion of said outer box, and. the insulation material comprises a separate bottom insulating blanket the edges of which engage the bottom edge portions of said liner portions to retain them in position after insertion of the bottom insulating blanket and before insertion of the inner box in said outer box.

9. A thermally insulated shipping container adapted to be knocked down for return shipment or storage in fiat condition comprising: a one-piece outer, open topped box having a bottom, front, rear and two side wall portions, ledge portions extending inwardly from the top edges of said front, rear and side wall portions, liner portions extending downwardly from the inner edges of said ledge portions; an inner box structure comprising front, rear, and side wall portions, a cover portion extending forwardly from the top edge of said rear wall portion, and a flap at the front edge of said cover portion insertable between the front wall portion of said inner box and the front liner portion of said outer box; and

insulation material interposed between the bottom wall portions of said outer and inner box and between the front, rear and side wall portions of said outer and inner box, said insulation material comprising relatively strong self-supporting blankets shaped to fit within the spaces between the bottom, front, rear and side Wall portions of the boxes.

References Cited in the file of this patent UNITED STATES PATENTS 1,351,278 Billstein Aug. 31, 1920 1,649,146 Bliss Nov. 15, 1927 1,701,323 Fredenhagen Feb. 5, 1929 1,882,524 Sherman Oct. 11, 1932 1,950,582 Ware Mar. 13, 1934 1,997,909 Luce Apr. 16, 1935 2,074,315 Neely Mar. 16, 1937 2,081,419 Benschoter May 25, 1937 2,149,955 Burns Mar. 7, 1939 2,481,871 Potts Sept. 13, 1949 2,491,206 Potts Dec. 13, 1949 FOREIGN PATENTS 197,998 Great Britain May 23, 1923 530,091 Great Britain Dec. 4, 1940 411-12.; .mai