CA1301085C - Air cargo container and method for forming side panels thereof - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

This invention discloses a cargo container (10) with transparent polycarbonate panels (12, 14, 16) held by inner and outer corner molding strips (18, 24). The molding strips (18, 24) are press-fitted together, form the corner joints (20) of the container (10), and retain the panel edge curru-gations (29, 30) by internesting the corrugations in a matching channel ((19, 25) formed by the mated strips (18, 24). The panel (12, 14, 16), therefore, is not penetrated by bolts, rivets, etc. The invention also discloses a method to progressively shape-form corrugations into preheated (to 120°F) panels by a series of roller dies, some of which are also heated to 110°F.

Description

~(31 ~ f85 This application relates to an improved air cargo container and enabling method and means for the construction th~reof. Also it pertains to an air cargo container corner construction which facilitates advantage in formation for assembly and disassembly of highly desired transparent and tough polycarbonate panels, in that it allows them for the first ~ime to be used effectively in air cargo containers.

Prior art containers and container structures have provided containers o* rigid and sturdy construction to sa~eguard cargo items being transported or stored therein. However, the side panels of the previous containers have been attached to the container frame most often using a bolt that passed through the panel. This made the use of a polycarbonate panel undesirable because of stress crazing and cracking that occurred around the bolt holes through which the bolt passed when attaching the panel. Additionally, the attempted use of nuts and bolts, rivets, fixings or the like to attach the side panel necessitated much effort to replace any side panel, in that removing the panel required disassembly of the nut and bolt combination. Special tools were often needed and the individual nuts and bolts were lost, especially under operating conditions for loading cargo containers into airplanes, i.e., urgency and sometimes poor illumination.
Additionally, the commonly used panel material, aluminum, is not transparent. Thus the cargo handlers cannot see how or to what extent the cargo container is loaded. The lack of transparency of prior panels also hid undesired acts of pilferage from plain view.

The present invention provides containers whereby the above noted disadvantages may be overcome.

The invention provides a cargo container having a top, a bottom and a plurality of side walls defining an enclosed interior, and having means defining peripheral .~
?11 corners of the cargo container comprising an elongated corner strip with a channel formation thereon defining a channel extending longitudinally of the strip, at least one of the walls of the container panel comprising a sheet of semi-rigid plastic material, preferably of polycarbonate, said panel having a channel section corrugation along a marginal edge, the corrugation being in interengagement with the channel formation with one side of the channel formation of the strip being received in the channel of the corruyation and a portion of the said marginal edge being received in the channel formation, and means for removably maintaining the interengagement between the corrugation and the channel formation.

With the container o~ the invention there has been eliminated any need to pass a bolt through the polycarbonate or other plastic material panel, stress crazing of the panel has been eliminated.

In one method for manufaciuring the cargo container, the edges of a transparent polycarbonate panel may be shape-formed into at least one corrugation by proeheating the panel edges, for example to about 55C
(120F) and passing the preheated panel edge through one or more roller dies disposed so as to progressively shape-form corrugations into the panel edges. The panel maythen be introduced between an outer and inner corner molding strip adapted to maXe lengthwise to form peripheral edges of a container. Threaded bolts may be inserted through aligned holes in inner and outer corner molding strips, but not penetrating said panel. The bolt is mated with a nut, the nut retained by non-rotatable means, and tightening effected to press fit and releasable retain the panel by the molding strips. Finally a door is attached over an opening left without a side panel between peripheral edges of the container.

~,~1, j BRIEF DESCRIPTION OF THE DRAWINGS

Having thus described the invention in general terms, reference will now be made to the accompanying drawings in which:

FIG. 1 is an enlarged cross-sectional view of the corner of an air cargo container.

FIG. 2 is the samé corner joint of the air cargo container shown in a disengagement mode.

FIG. 3 is the same corner joint as shown in PIG.
1 with the upper nut removed to better illustrate details of the invention.

FIG. 4 is a horizontal elevation of the shaping apparatus.

FIG. 5 is a partially cut away vertical elevation of the apparatus.

FIG. 6 is a partial horizontal cross-section of the shaping apparatus taken along line 6-6 shown ln FIG.
4.

Fig. 7 is a partial horizontal cross-section of the shaping apparatus taken along line 7-7 in FIG. 4.

FIG. 8 is a partial horizontal cross-section of the shaping apparatus taken along line 8-8 in FIG. 4.

FIG~ 9 is a perspective view of a container constructed in accordance with the invention herein claimed.

:~31~

D~TAILED DESCRIPTION OF_THE PREFERRED ENBODIMENT

Referring to the drawings, l:ike numbers of reference indicate like elements throughout. In FIG. 3, peripheral corner 20 of container 10 is constructed with an outer corner channel strip 18 having flanged edges 22 adapted to mate lengthwise with an inner corner molding strip 24 and retaining side panel skins 26 thereinbetween to form the peripheral corner 20 of container 10.

An outer panel skin 26 forms a side of container 10. Peripheral edges 28 of outer panel skin 26 are adapted to be inserted and releasably retained between outer channel strip 18 and inner molding strip 24.

The corrugated configuration of the peripheral edges 28 of the outer panel skin 26 is formed by rolling parallel ridges 29 and 30 (including corresponding grooves or channels 30a, 30b) around the four edges of each panel.
The ridges are retained within corresponding longitudinal grooves 25 and 19, in the inner and outer molding strips 24 and 18, respectively. A projecting lip 27 of the inner molding strip 24 mates with ridge 29 and forces it into a groove or channel 19 of the outer channel strip 18.
Simultaneously, the flanged sides or edges 22 of the outer channel strip 18 mate with the ridge 30 of the two side panel skins 26 and force them into opposite grooves 25 of the inner corner molding 24. Projecting lips 23 on the underside of the outer channel 18 mate with preferably semicircular grooves 39 on the inner molding 24 and give the joint integral strength when the two moldings are clamped together. Thus, when threadably tightened, a bolt and nut combination 34 and 32 will compress and retain in a releasable lengthwise relation, the corrugated peripheral edges 28 of the outer panel skins 26 inserted between the inner and outer corner molding strips 24 and ,iyr .,'q ~3~

18 to form the structural corner 20 of the container 10.

It will be noted that, with this arrangement, a side 22 of each channel formation 19 of the strip 18 is received in a channel 3Oa of the corrugation of the panel 26, and an outer portion 28 or 29 of the panel is received in the channel 19. The portions 27 and 25 remo~ably maintain the interengagement.

The bolt 34 is inserted through aligned holes 36 in the inner and outer corner molding strips 24 and 18 and hole 37 in a short channel piece 38. The nut 32 is held rotationally immohile in the channel 38 which is slidably inserted in the inner corner molding strip 24 and therein held in place by channel-like extensions 35 protrud:ing from the inner side o~ molding strip 24. The nut holding channel 38 is therein retained by inwardly protruding lips.

Thus, as best shown in FIG. 2, in the replacement of damaged outer panel skins 26, the component parts comprising the structural corner 20 are not totally dismantled and the bolts and nuts 34 and 32 remain engaged in the channel molding strip 18 and inner molding strip 24, thus preventing their separation and loss.

130~ BSi ii~,. b The configuration of channel 38 shown in FIGo 3 is modified by the addition of an integrally formed U-shaped extrusion 106, as shown in FIGS. l and 2q In this embodiment, the projecting end 108 of the bolt 34, when tightened in nut 32, is protectively encapsulated by channel 38 with its U-shaped extrusion 106, thus preventing damage to the extended end of bolt 34 or the thread thereon and also the cargo stored within the container. When the bolt 34 is tightened during the assembly of the peripheral corner 20 of the container lO, its length is such as to cause a dimple 107 in the U-shaped portion 106 of the channel 38. Thus, the mating of the bolt end 108 and dimple 107 prevents the channel 38 from sliding from its position encompassing the nut 32, especially on the veL~tical corners. When the bolt 34 is rotatably retracted to the position shown in FIG. 2, its end 1~8 remains threadably engaged with the nut 32. This retracted position permits the disengagement of the outer skin 26 which was retained between the outer molding strip 18 and the inner molding strip 24.
Thus, the component parts comprising the peripheral corner 20 are not totally dismantled during the attachment and/or replacement of the outer skin panel 26.
In the second preferred embodiment as shown in FIGS. 1 and 2, it should be noted that a washer llO and supporting nut 112 are threadably mounted on bolt 34 in a counterbored recess 114 in the undexside of the molding strip 18. The self~locking nut 112, commercially known as a "nyloc-nut", has a nylon insert which clinches the nut onto the threads of the bolt 34 in a ~3(~:JL~S

relative position allowing a clearance space between the washer 110 and molding strip 18, thus permitting the bolt to rotate in the hole 36 and in the outer mslding strip 18. Thus, when the bolt 34 is rotatably retracted to its outer position as shown in FIG. 2, the washer 110 and nut 112 rotate with the bolt and remain in their relative position affixed upon the bolt 34. The nut being held rotationally immobile in the channel 38 unscrews from the bolt 34, thus forcing the outer molding strip 18 to disengage from its locking position with inner molding 24 and, thereby, releasing outer skin 26.
Referring now to FIG. 9, the invention is shown embodied in the form of a cargo container 10, specifically, an air cargo container. rr'he container comprises a top 12, a bottom 14, and a plurality of exterior side walls 16. The actual exterior shape of the container 10 can be contoured to occupy a particular location as, for example, against the curved hull of a cargo aircraft or a seagoing vessel, by the addition of angled and/or shortened walls 16a. Through access opening 54 can be seen hinged handles 74, gusset plates 78 and threshold channel 82 to which a flexible door flap (not shown) may be attached and secured. The peripheral corner 20 of the container 10 has bolts 34 accessible from the surface and penetrating the corner thereof, as shown in FIGS. 1 - 3. The lower panel portions 58 of the side walls 16 are reinforced with peripheral hollow stiffener members 60 forming a structural frame around the bottom 14.

Referring now to FIG. 4, which is a horizontal elevation of apparatus 212, the apparatus 212 can be composed of two sections, the heating means 214 and shaping means 216. The heating means 214 is composed of one or more heating lamps 218 enclosed as in a shroud 220. This shroud 220 can be mounted on a pole 222 by clamp 224. Clamp 224 can be loosened and the heating means 214 adjusted up ~nd down. This allows the distance between the heating means 214 and the shaping means 216 to be varied.
The lamps 218 can be such as infra-red heat lamps.
Typically, these heating lamps draw 250 watts of electric current. For example, a collection of 7 heating lamps, can raise the temperature of a metal part up to around 110F (49C) approximately when positioned 14 inches away.
The shaping means 216 is composed of a series of opposed roller dies 226 and 228, wherein roller die 226 is disposed on top of roller die 228. Although FIG. 4 shows eight such pairs of roller di~s 226 - 226G and 228 - 228G, the number of opposed roller die pairs can be varied depending upon the geometry desired in the final edge of the plastic sheet to be shape-formed. The roller dies 226 and 228 rotate in the same direction, i.e., from right to left. Positioning means 230, shown in FIGo 6, allows the sheets to be introduced into the series of opposed roller dies. The sheet 236 travels from right to left in FIG~ 4 encountering the roller die pairs in alpha-betical order after roller die pairs 226 and 228. When the c~ 8~
sheet 236 encounters the roller die pairs, and afterwards, the roller dies with the third roller dies 238 - 238C, the sheet edge is progressively shaped into the corrugations for inter-nesting with a channel defined by the edges of the corner molding strips.The roller dies 226 - 226G and 228 - 228G are powered by electric motors.
FIG. 5 is a vertical elevation of apparatus 212. Heating shroud 220 is shown in phantom to show its position in relation to the top roller die 226. Alternatively, the heating assembly could be configured to heat all the top roller dies or even all the roller dies, bottom and top. As seen in FIG. 6, positioning means 230 is composed of a horizontal table 232 with a guide 234 composed of angle iron mounted above the table 232. The angle iron of guide 234 is mounted sufficiently far above the table 232 to allow a sheet of plastic material to slide along felt webbing placed on top of the table 232. The positioning means 230 guides the sheets of thermoplastic material into the series of opposed roller dies 226 - 226G and 228 - 228G.
FIG. 7, which is a partial horizontal cross-section of the apparatus 212, shows a sheet 236 of thermoplastic material going through the first pair of roller dies 226 and 228. The roller dies are deforming the thermoplastic material sheet 236 as shown.
FIG. 8, which is a partial horizontal cross-section,,taken along lines 8-8 in FIG. 4, shows the thermoplastic material sheet 236 as it emerges from the last set of roller dies 226 and 3L;~J~ 3LGr~35 /i io --~6--228. Also impinging upon the thermoplastic sheet 236 is a third roller die 238, the last in a series of third roller dies 238 -238C. As can be seen, the set of three roller dies 226G, 228G
and 238 are beyond the range of heating means 214. However, due to the pre-heating of the panel and the heating of the ~irst series of roller dies, the thermoplastic material is still amenable to shaping. Also illustrated in FIG. 8 is the complex shape with the minimal radius of curvature for the ridges formed in the edge of sheet 236.
The apparatus and method of the present invention ~aintains enough heat in the edge of the sheet 236 of plastic material so that the edge may be shaped into the desired geometry by the series of roller dies 226 - 226G, 228 - 228G and, if needed, 238 - 238C. The heat is transferred into the sheet 236 by first heating the panel separately to 120F before putting the sheet into the apparatus. The top roller die 226 is heated, in turn, by the heating means 214O The heat transfer from the roller die 226 to the sheet 236 is accomplished by direct contact and is to maintain the sheet temperature near 120F. The heat transfer from the heating means 214 to the top roller die 226 is accomplished by radiation heating where heat lamps 218 are used.
In the case of infra-red heat lamps, in an assembly of 7 heat lamps together, the temperature of the top roller die 226 reaches 110F (49C). This is sufficient to maintain enough heat in the plastic sheet 236 to make it amenable to shaping by the roller die 226 and 228. Thus, the sheet 236 is pliable enough to be reshaped into the desired geometry.

- ~ -One specific use of the apparatus and method for shaping the edges of thermcplastic material sheets is in manufacture of advanced air cargo containers. It is desirable that the side panels of air cargo containers be light, yet strong enough to withstand rough handling and other abuses. Polycarb~nate material, such as polycarbonate produced by General Electric Company, meets this requirement. In one specific type of air cargo container, the geometry required for the edges of the side panel skins consists of a series of corrugations. The radius of curvature is typically the thickness of the sheet material. In the case of polycarbonate, cold forming techniques are not recommended where the radius of curvature is less than 100 times the thickness of the sheet material. If the radius of curvature is less/ stress crazing can result.
In particular, it has been found that a collection of infra-red heat lamps, positioned in a shroud assembly about 14 inches from the top roller die, was sufficient to raise the temperature of the top roller die to 110~F ~49C~. In particular, when a sheet of l/16th inch thick of polycarbonate is introduced into the shaping means containing the roller dies, above which the heating assembly described hereinbefore is mounted 14 inches away from the initial top roller dies, the complicated geometry required for side panels of air cargo containers can be shaped-formed into the edges of the sheet.
A most important feature of this invention is the joint as used with the particular polycarbonite material~ The joint is a continuous joint so that every piece of the joint is providing 'BS

_~3 strength. When there is a riveted or bolted or any mechanical joint, the strength is provided by the rivet, and if the rivets are at half-inch, one inch, two inch, or whatever pitch that they are, the strength is only provided at those points and pitches. If high strength is desired, a very high number of fixings, rivets, bolts, or whatever have to be employed. ~or the present container with the polycarbonate panel, tests have shown tha~ loads of 500 lbs. per inch were obtained. The area of the joint or the linear length of the joint on top of the present container is 160 inches plus 120 inches which gives approximately 280 inches and, at 500 lbs. per inch, it gives the staggering load of approximately 150lO00 lbs. Without use of the herein described joint, it would need probably a treble line of rivets every half inch to approach the load which is obtained from this joint. The cost of doing that would be prohibitive, The added weight would be prohibitive. The maintenance costs would be prohibitive. With the present design, one man with a power screwdriver can remove or replace a panel in five minutes.
Thus, a massively high level of strength equal to the tensile strength of these polycarbonate sheets is achieved, coupled with ease of assembly and disassembly are achieved.
Another feature of this design is that the joint creates its own hollow section which provides greater stiffness of the frame. In either of these materials, aluminum or polycarbonate, the container structure produces a diaphragm effect as with drums where the skin of the drum is in tension against a strong outside periphery. There is still flexibility so that, when it ~OlG 8~i receives a blow, it absorbs a tremendous amount of energy before breaking. The strong frame is achieved by way of the extrusions ~inner and outer corner molding strips3 which are made stronger because the clamping extrusion forms a hollow section as two independent clamping extrusions come together to form a hollow extrusion, which means that the stiffness of the frame is very much greater than it would otherwise be.

The joint that has been disclosed herein enables polycarbonate panels to be used. Polycarbonate has been around for many years, but it has never been able to be used in this application, because the only way of fixing it to any box is by way of fixing it by rivets, or whatever, which would inevitably fail due to stress corrosion. As noted, there are no holes in the instant design; therefore, the disclosed joints make polycarbonate useable and it cannot be used without this type of joint.
Referring to FIG. 3, in the preferred form the two inner legs of the capping extrusion have small b~ads 23. The small beads fit into the recesses marked 39 on the structural extrusion by driving past rims 21 which go back to the position shown in FIG. 3 once the beads have passed by. ~hen these two beads are connected and home, the two extrusions become as if they were one integral extrusion.
The force required to make them and to disengage them is very, very significant.

The jackbolt, which is item 108 (FIG. 3), is the means of forceably removing the capping extrusion (outer corner molding strip) from the structural extrusion (outer corner molding strip). When these two legs 23 are connected to the structural extrusion, the capping is fixed and the fixing joint, which is shown on the panel, is sufficient to prevent the panel from coming out. It should be noted that the grooves are deep. It therefore means that if the snap-fit is to pull out, the leg 23 must bend. And when the leg bends, it comes into the side and ~,i ,_ ,, 13~ i35 the more it comes into the side the more it jams. The same eff~ct is experienced on the insicle area about the number 39. So this becomes absolutely fixed because the two legs are fixed in the center at 23, 39.

The bolts 34 themselves are not necessary from a structural point of view. The bolts enable the capping to be put on and taken off. It therefore, in effect, produces a joint which requires no bolt for the purpose of the joint. After pressure is put on by the bolt, the two middle legs 23 bend inwards and as they get past the cam-like rims 21, they spring back (as little as .020"), which makes a firm snap and a permanent connection between the capping and structural extrusions until forced apart, as by the jackbolt 108 (Fig. 3).

Preferably, the outside capping leg fits into a U-section. The yap in that U-section is preferably designed to be no more than 1/16th of an inch. The polycarbonate panel is preferably 1/16th of an inch throughout (including its formed edges). The more load that goes on the panel the more it tends to cram or jam into the adjacent structural extrusion.

The invention described above is susceptible to many variations, modifications and changes, all of which are within the skill of the art. It should be understood that all such variations, modifications and changes are within the spirit and scope of the invention and the appended claims. Similarly, it will be understood that it is intended to cover all changes, modifications and variations of the example of the invention herein disclosed for the purpose of illustration which do not constitute departures from the spirit and scope of the invention.

Claims (28)

1. A cargo container having a top, a bottom and a plurality of side walls defining an enclosed interior, and having means defining peripheral corners of the cargo container comprising an elongated corner strip with a channel formation thereon defining a channel extending longitudinally of the strip, at least one of the walls of the container panel comprising a sheet of semi-rigid plastic material, said panel having a channel section corrugation along a marginal edge, the corrugation being in interengagement with the channel formation with one side of the channel formation of the strip being received in the channel of the corrugation and a portion of the said marginal edge being received in the channel formation, and means for removably maintaining the interengagement between the corrugation and the channel formation.

2. A container as claimed in claim 1 wherein the plastic material is polycarbonate.

3. A container as claimed in claim 1 wherein said means for removably maintaining the interengagement comprise a member engaging said portion of the said marginal edge and urging it into said channel formation.

4. A container as claimed in claim 1, 2 or 3 wherein the channel section corrugation is formed along an edge of the sheet of plastic material.

5. A container as claimed in claim 1, 2 or 3 wherein said sheet of plastic material is transparent or translucent whereby the contents of the cargo container may be received therethrough.

6. In combination with a cargo container having a top, a bottom and a plurality of side walls defining an enclosed interior, the improvement comprising:
(a) means defining peripheral corners of the cargo container, the means comprising:
(i) an elongated corner channel strip defining a longitudinally extending edge projecting therealong, and (ii) an elongated molding strip defining a longitudinally extending groove therealong;
(b) at least one of the walls of said container comprising a panel comprising a sheet of semi-rigid polycarbonate plastic material, said panel having along a marginal edge a ridge and a groove, the longitudinally extending edge of said channel strip being releasably inserted into and seated within the groove in the marginal edge of said panel while its corresponding ridge is releasably inserted into and seated within the groove of said molding strip; and (c) means for removably maintaining the longitudinally extending edge of said channel strip within the edge groove of said panel and for removably maintaining the corresponding ridge of said panel within the groove of said molding strip to form a peripheral corner of the cargo container whereby said panel may be selectively detached from said corner for repair and replacement without penetration of said panel.

7. The improvement in a cargo container as claimed in claim 6 wherein the plastic material is polycarbonate.

8. The improvement in a cargo container as claimed in claim 6 wherein the edge of the sheet of plastic material has a ridge and the groove along said marginal edge.

9. The improvement in a cargo container as claimed in claim 6, 7 or 8 wherein said sheet of plastic material is transparent or translucent whereby the contents of the cargo container may be viewed therethrough.

10. In a cargo container having a top, a bottom and a plurality of side walls with interlocking corner joints at the peripheral corners thereof and defining an enclosed interior, the improvement comprising:
(a) elongated corner molding strips at said corner joints defining longitudinally extending groove means, said strips defining the peripheral corners of said container;
(b) unperforated semi-rigid panels of sheet plastic material forming the walls of said container, said wall panels having peripheral edge portions with an extending ridge provided therealong, and said panels in each of said edge portions being adapted at its extending ridge to be inserted into and seated within a groove means of a corner molding strip;
(c) corner channel strips each including a longitudinally extending edge adapted to be inserted into the extending ridge of the edge portion of a wall panel inserted into and seated within a groove within a groove means of a corner molding strip; and (d) means for removably maintaining a corner channel strip within the extending ridge of the edge portion of each wall panel and for removably maintaining the extending ridge of the edge portion of each wall panel within a groove means of a corner molding strip whereby the edge portions of each wall panel are releasably retained between a corner channel strip and a corner molding strip thereby forming an interlocking joint at the peripheral corners of said container.

11. The improvement in a cargo container r as claimed in claim 10 wherein the sheet plastic material of said wall panels is transparent.

12. The improvement in a cargo container as claimed in claim 11 wherein the sheet plastic material of said wall panels is translucent.

13. The improvement in a cargo container as claimed in claim 10, 11 or 12 wherein the sheet plastic material of said wall panels is formed from a polycarbonate plastic material.

14. In a cargo container having a top, a bottom and a plurality of side walls defining an enclosed interior and having interlocking joints at the peripheral corners thereof for ease in the assembly and disassembly of said container, the improvement comprising:
(a) elongated corner molding strips at said corner joints defining longitudinally extending groove means, said strips defining the peripheral corners of said container.
(b) unperforated semi-rigid panels of sheet plastic material forming the walls of said container, said wall panels having corrugated peripheral edge portions presenting an extending ridge, and said panels in each of said corrugated edge portions being adapted at its extending ridge to be releasably inserted into and seated within the groove means of a corner molding strip;
(c) corner channel strips each including a longitudinally extending edge adapted to be releasably inserted into the extending ridge of the corrugated edge portion of a wall panel inserted into and seated within the groove means of a corner molding strip;
and (d) means for removably maintaining a corner channel strip within the extending ridge of the corrugated edge portion of at least one of said wall panels and for removably maintaining the extending ridge of the edge portion of said at least one wall panel within a groove means of a corner molding strip whereby the corrugated edge portions of said at least one wall panel are releasably retained between a corner channel strip and a corner molding strip thereby forming an interlocking joint at a peripheral corner of said container.

15. The improvement in a cargo container as climaed in claim 14 wherein the plastic material is polycarbonate.

16. The improvement in a cargo container as claimed in claim 14 wherein the sheet plastic material forming the walls of said container is transparent.

17. The improvement in a cargo container as claimed in claim 14 wherein the sheet plastic material forming the walls of said container is translucent.

18. A construction for a cargo container having a top, a bottom and a plurality of side walls defining an enclosed interior comprising:
(a) means defining peripheral corners of the cargo container, the means comprising:
(i) a corner channel strip defining a longitudinally extending groove means opening in a first direction and including a longitudinally extending edge; and, (ii) a molding strip defining a longitudinally extending groove means opening in a direction generally opposite to said first direction and including a longitudinally extending projecting lip;
(b) a wall of the container comprising a continuous unperforated semi-rigid panel with peripheral edges having parallel ridges formed therealong; and, (c) attaching means to removably attach the corner channel strip to the molding strip such that a ridge of the semi-rigid panel and the projecting lip of the molding strip extend into the groove means defined by the corner channel strip, and a ridge of the semi-rigid panel and the edge of the corner channel strip extend into the groove means defined by the molding strip so as to clamp the peripheral edge of the semi-rigid panel between the corner channel strip and the molding strip, the attaching means comprising:
(i) nut retaining means on the inner molding strip;
(ii) nut means non-rotatably retained in the nut retaining means; and, (iii)threaded means extending through the outer corner channel strip and the inner molding strip, and threadingly engaging the nut means.

19. The cargo container construction according to claim 18 wherein the semi-rigid panel is formed from a plastic material.

20. The cargo container construction according to claim 19 wherein the plastic material is transparent.

21. The cargo container construction according to claim 19 wherein the plastic material is translucent.

22. The cargo container construction according to claim 19 wherein the plastic material is polycarbonate.

23. The cargo container produced by the method of:
shape-forming the edges of a transparent polycarbonate panel into at least one corrugation by preheating the panel edge and passing said preheated panel edge through one or more roller dies disposed so as to progressively shape form corrugations into the panel edge;
introducing said panel between first and second corner molding strips adapted to mate lengthwise to form peripheral edges of said container;
tightening threaded bolts inserted through aligned holes in the first and second corner molding strips, but not penetrating said panel, said bolt mated with a nut, said nut retained by non-rotatable means, said tightening effecting a press-fitting and releasable retaining of said panel by said first and second corner molding strips; and attaching a door over an opening left without a side panel between peripheral edges of container.

24. A confined storage space for cargo produced by the steps of:
shape forming the edges of a transparent polycarbonate panel into at least one corrugation by preheating the panel edge and passing said preheated panel edge through one or more roller dies disposed so as to progressively shape-form corrugations into the panel edge;
introducing said panel between first and second corner molding strips adapted to mate lengthwise to form peripheral edges of said container;
tightening threaded bolts inserted through aligned holes in the first and second corner molding strips, but not penetrating said panel, said bolt mated with a nut, said nut retained by non-rotatable means, said tightening effecting a press-fitting and releasable retaining of said panel by said first and second corner molding strips; and attaching a door over an opening left without a side panel between peripheral edges of container.

25. A cargo container whose construction comprises:
first and second corner molding strips adapted to mate continuously lengthwise, sharing between them an uninterrupted lip and groove combination for snap fitting said molding strips together, said molding strips shaped into internesting corrugations at their edges; and panels shaped into corrugations at the edges, the edges adapted to internest with said corrugations of said molding strips, said panels when internested with said molding strips at all edges of said panel being under tension; and means for forcing said corner molding strips together to confine the corrugated edges of said panels and for forcing snap fitted molding strips apart thereby releasing said panels.

26. The container of claim 25 wherein said means for forcing the molding strips together and apart consists of a threaded bolt inserted through said molding strips, but not penetrating said panels, said bolt mated with a nut, said nut held by means in a non-rotatable relationship.

27. The container of claim 26 wherein said bolt is mated with said nut in such a way that said bolt never separates from said nut, and said nut is positioned in relationship with said molding strips so that said bolt never disengages from said molding strips.

28. The container of claim 26 wherein said nut holding means consists of a U-shaped channel mating lengthwise with one of said corner molding strip and further having an inner protuberance preventing lengthwise movement of the nut and bolt in the channel, the depth of the channel being less than the length of the threaded bolt, so that when the threaded bolt is fully tightened, the bolt contacts the wall of said U-shaped channel strip.