US3784043A

US3784043A - Lightweight collapsible structures

Info

Publication number: US3784043A
Application number: US00050065A
Authority: US
Inventors: M Presnick
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-11-29
Filing date: 1970-06-26
Publication date: 1974-01-08
Anticipated expiration: 1991-01-08

Abstract

A lightweight, collapsible or knock-down parallelepiped structure and other geometric structures, such as geodesic domes, having a high strength-weight ratio, erected without tools from series of standardized wall sections are disclosed herein. Each wall section of the structure comprises a plurality of framing rails which define a closed frame, which supports a rigid sheet of lightweight, durable paneling. The cross section of the framing rials is hermaphroditic, i.e., it is especially configured to mate with itself. The appropriate mating of two of the framing members is the first step in forming a unique edge joint of the structure without the use of tools. The edge joint is rigidly established by swinging toggle clamp members which firmly lock together the mating framing members of adjacent wall sections. When desired, the new structure may be disassembled or knocked down, also without tools, for storage in minimum space, by releasing the toggle clamp members by a simple pivoting movement. Spring keeper elements hold the toggle clamps in predetermined relation to the wall sections in both the operative and inoperative positions of the toggle clamps.

Description

O Unlted States Patent 1 1 1 3,784,043 Presnick Jan. 8, 1974 [54] COLLAPSIBLE FOREIGN PATENTS OR APPLICATIONS 1,474,966 2/1967 France 220/4 R [76] Inventor: Michael C. Presnick, 111 554,255 6/1957 Italy 220/4 R Bloomingdale Rd., New York, NY. 1 1301 Primary Examiner-George E. Lowrance 1 J e 2 Att0rney-Mandeville and Schweitzer [21] Appl. No.: 50,065 57 ABSTRACT Related US. Application Data A lightweight, collapsible or knock-down parallelepi- [63] Continuation-impart of Ser. No. 779,750, Nov. 29, ped Structure and other geometric structures Such as 1968, P N 3,517, 49 geodesic domes, having a high strength-weight ratio, erected without tools from series of standardized wall [52] US. Cl 220/4 F, 220/84, 287/2092 T, sections are disclosed herein. Each wall section of the 287/ 189.36 D structure comprises a plurality of framing rails which 51 Int. Cl. B65d 7/30, F16b 5/00 fin a closed frame, which pp a rigid Sheet of [58] Field of Search 220/4 R, 9 F, 80, g gh le p neling- The cro s section of the 220/75, 76, 84, 4 F; 217/69 65 69; framing rials is hermaphroditic, i.e., it is especially 287/2092 D, 2092 Y, 20.92 T, 20.92 R, configured to mate with itself. The appropriate mating 1393 1 1 93 1 93 1 93 c of two of the framing members is the first step in forming a unique edge joint of the structure without [5 6] References Cit d the use of tools. The edge joint is rigidly established by UNITED STATES PATENTS swinging toggle clamp members which firmly lock to- 2 961 H6 11/1960 Je son 220,9 F gether the mating framing members of adjacent wall 325l382 5,1966 i 1:: /9 F Ux sectlons. When desired, the new structure may be dis- 3:288:3l9 11/1966 Cahill 217 65 x assembled or 3,044,656 7/1962 Combs 220/4 R Storage in minimum Space, by releasing the toggle 2,919,826 1/1960 Richter 1. 220/4 R clamp members y a Simple pivoting movement- 2,495,862 1/1950 Osborn... 287/2092 T X Spring keeper elements hold the toggle clamps in pre- 2,577,l20 l2/l95l Franz 217/65 UX determined relation to the wall sections in both the 2,539,304 3/ 1952 p g 237/189-36 H UX operative and inoperative positions of the toggle 2,837,365 6/1958 Schlueter.... 287/l89.36 D X c]amps 2,884,296 4/1959 Meilinger.... 287/2092 C UX 3,547,472 12/1970 Ehrman 287/2092 T 4 s, 8 Drawing g r PATENTEU JAN 81974 SHEET 1 BF 3 INVENTOR MICHAEL C. PRESNlCK ATTORNEYS PATENTEI] JAN 81974 SHEET 3 OF 3 FIGQ6- FIG. 7

FIG. 8

INVENT OR. MICHAEL C. PRESNICK ATTORNEYS LIGHTWEIGHT COLLAPSIBLE STRUCTURES RELATION TO CO-PENDING APPLICATION This application is a continuation-in-part of copending application Ser. No. 779,750, filed Nov. 29, 1968, issued as US. Pat. No. 3,517,849.

SUMMARY OF THE PRESENT INVENTION The present invention provides a new and improved collapsible structure of especailly light weight in comparison to structures of comparable storage capacity and of strength substantially equal to or greater than previously available structures of comparable capacity. The new structures may be simply assembled by unskilled laborers from standardized and interchangeable wall sections, without the use of tools, and conversely they can be disassembled and completely collapsed for storage, without the use of tools, by virtue of a new and improved framing rail and edge joint construction.

More specifically, each of the wall sections for the structures of the invention are comprised of a rigid light weight frame made from a hollow extrusion or rail having a unique, hermaphroditic cross section. The configuration of the framing rail cross section is such that it is generally four-sided and includes a planar wall, a specially shaped key opposite the planar wall, a bifunctional, canted locking slot on a third wall, and a shallow groove on the fourth wall. An extension of the first wall together with a projecting flange from the fourth wall cooperate to form a panel retaining channel.

In accordance with the invention, predetermined lengths of the new hollow extrusion may be cut at right angles to its length and then connected together at predetermined angles to form closed frames by the use of angular corners which are appropriately shaped to fit within the hollow portions of the extruded frame members and to define the angle ofjunction. As will be understood, each wall section for the new structures may be fabricated by framing an appropriately shaped panel of rigid lightweight material such as reinforced corrugated board, plywood, alumunum or steel foil sandwiched about a core, etc.

In accordance with a very important aspect of the present invention, selected wall sections will carry pivotable toggle clamp members, which are adapted to clamp wall sections together in a predetermined rigid, edge joint generally established by the mating of the key portion of one wall section frame rail with the bifunctional slot of an adjacent wall section frame rail.

For a more complete understanding of the invention and a better appreciation of its attendant advantages, reference should be made to the following detailed description taken in conjunction with the accompanying drawings.

DESCRIPTION OF DRAWINGS FIG. 1 is a perspective view of an intermodal, collapsible, parallelepiped structure embodying the principles of the invention; I

FIG. 2 is an exploded, perspective view of the elements required to form a corner of a wall section for the new structure;

FIG. 3 is a plan elevational view of a corner of a wall section of the new structure showing the toggle clamp members in an inoperative position; and

FIG. 4 is a cross-sectional view of the new structure edge joint taken along line 44 of FIG. 3 and showing nested frame rails locked together by a toggle clamp member in accordance with the invention;

FIGS. 5, 6 and 7 are cross-sectional views of alternate preferred embodiments of the framing rail of the invention; and

FIG. 8 is a perspective view of a geodesic structure embodying the inventive principles.

DESCRIPTION OF PREFERRED EMBODIMENT Referring initially to FIG. 1, a preferred form of the structure of the invention is a rectangular parallelepiped 10 which comprises a front wall section 1 1, an end wall section 12, a rear wall section 13 (not visible in FIG. 1), an end wall section 14, a top wall section 15, and a bottom wall section 16. It is to be understood, of course, that structures embodying the inventive concepts will assume many other shapes, depending upon the ultimate use of the structure.

In accordance with the invention and as shown in FIG. 1, each of the wall sections 1 1-16 of the structure 10 is formed from a panel 17 of durable, lightweight, substantially rigid sheet material, which panel is cemented into a circumscribing frame 18 for support and stiffening. In accordance with the principles of the invention, each of the frames 18 is built up from a standard or universal hollow frame rail 19 (FIG. 2), having a unique tubular cross section especially designed to perform a multiplicity of functions. Advantageously, the frame rails are of extruded aluminum, ABS, or other high impact strength plastic construction.

Specifically, the new framing rail member 19 is adapted to be selfmating with a rail member of identical cross section when rotated i.e., it is hermaphroditic; it is adapted to hold and to stiffen the wall panel material 17 in a flat plane recessed from the periphery of the finished container; it is adapted to provide a groove in which a pivotable toggle clamp may be disposed in operable association therewith; it is adapted to receive a sealing gasket between itself and a mating frame rail; and it is adapted to be rigidly locked to a mating frame rail by a pivotable toggle clamp.

More specifically and with reference to FIG. 2, the hollow frame rail 19 of the invention includes an outer substantially planar wall 20 and a planar inner wall 21 having a wedge-shaped key 22 projecting centrally therefrom. The key 22 has convergent sides 23 and a flat face 24. The inner and outer

frame rail walls

20, 21 are spaced from one another by a panel retaining wall 25 and a locking wall 26. As shown, the retaining wall 25 includes a projecting flange 27 which is parallel with an extension or flange 28 of the inner wall 21. The

flanges

27, 28 cooperate to define a channel 29 of sufficient width to receive and to securely hold the container wall sheet material 17. The

flanges

27, 28 include grooves 35 at their inside surfaces, which grooves provide additional surface area for establishment of the cement bond between the channel 29 and the paneling l7 and which grooves prevent bonding material (usually epoxy) from flowing beyond the

flanges

27, 28. The panel retaining wall 25 also includes a shallow groove 30 which extends longitudinally parallel to the axis of the frame rail.

The locking wall 26 of the frame rail includes a canted, deep slot 31, the divergent mouth of which is defined by

spaced lands

32, 33 which are generally shaped to matingly receive the wedge-shaped key 22. As shown, the land 33 is formed generally by a rounded hollow corner 33' connecting the

rail walls

20, 26, while the land 32 is formed by a solid locking lip 34 which defines one wall of the slot 31. In accordance with the invention, the rounded edges 33 are the outermostedges of the erected container and contribute to safety in handling of the erected structure and to the even distribution of shock forces. As will be understood, the slot 31 is deep enough and sufficiently canted to receive and to hold the hooked locking portion of a toggle clamp, as will be described in greater detail hereinafter.

The individual lengths of frame rails 19 required to form a frame 18 are advantageously cut from pieces of stock by 90 cuts and are connected together to form frame corners by an angle piece or frame connector 40 having a central portion with external contours which are generally flush with external contours of the rails with one exception. The inner face 41 of the frame connector 40 is planar and is flush with the wall 21 (and not the key 22) for reasons to be discussed hereinafter. Planar surfaces 42 and slot 43 of the connector 40 are generally flush with the slots 31 and outer wall surfaces 20 of the rails 19 which are to be joined to form a frame 18. A pair of solid legs 45 having cross sections generally similar to the hollow portions of the tubular rails 19 project outwardly from the central portion of the connector and mutually define the angle of juncture of the connector. in the illustrated preferred embodiment in which each of the structure wall sections is rectangular, the corner connector 40 will, of course, be L-shaped or perpendicular. As will be understood, shoulders 46 are formed where the central connector portions are joined with the legs 45. Advantageously and as shown in FIG. 2, the connector 40 is of solid construction, although a hollow connector may be employed with efficacy in some applications.

As an important aspect of the invention, the surfaces 41 of the frame corner connector 40 are suitably recessed in relation to the keys 22 to allow framed wall sections (for example, sections 11, 12 in FIG. 1) to be mutually butted in the formation of the completed structure without interference from the keys.

The corner of a framed wall section may be simply completed in accordance with the invention by telescoping the hollow frame rails 19 over the legs 45 and into contact with shoulders 46 formed in the corner 40.

Permanence and absolute rigidity of the established corner may be ensured by applying a thin coat of epoxy cement to the surfaces to be joined before they are telescoped. Of course, other adhesives or suitable mechanical fasteners may be employed in lieu of epoxycement, if desired.

From the foregoing, it will be apparent that wall sections of all sizes and shapes can be easily fabricated from readily available lightweight sheet material, such as plywood or sheet aluminum, laminated to a honey comb core.

As a most important aspect of the invention, completed wall sections may be quickly, simply, and efficiently connected together, without any tools whatever, to form the rigid structure through the employment of novel toggle clamps 50 carried by selected ones of the wall sections. For example, in a rectangularly prismatic structure having 42 X 58 inches front and rear walls and 42 X 42 inches end walls and especially suited for use as a cargo container, three clamps would be carried at the top and bottom edges of the front and rear walls and two clamps would be carried by the side edges of the front and rear walls and by the top and bottom edges of the end walls, a total of 28 clamps. However, for the sake of brevity of description and similicity of illustration, only a few of these toggle clamps 50 have been shown in FIG. 1. As a specific aspect of the invention, the clamps 50 are held in a recessed relation within the periperhy of the container by a keeper member 70.

More specifically and in accordance with the principles of the invention, each toggle clamp assembly 50 includes an operating lever 51 and pivoting locking member 62, both of which are formed from heavy wire which has been appropriately bent into the illustrated shapes. As shown in FIGS. 3 and 4, the lever 51 is of closed shape and has a fulcrum rod portion 52 spaced from a pair of pivot axis portions 53 by parallel leg portions 54. An elongated handle 55 having a slightly upturned distal end 56 is connected to the pivot portions.

The locking member 62 includes a pair of elongated parallel locking portions 63, the hooks 64 of which are interconnected by a transverse locking bar 65. The free ends of each of the locking portions 63 are bent back upon themselves and around the pivot axis portions 53 of the operating lever 51 to form loops 66 and to effectively articulate the locking member 62 to the lever 51 to form a locking clamp assembly 50. As shown, each of the loops 66 is in the nature of a stabilizing foot for the clamp assembly 50.

The toggle clamp assembly 50 is associated with each wall section by placing the fulcrum rod 52 in the shallow groove 30. Thereafter, the books 64 are swung up, over, and loosely into the canted locking slot 31 of an appropriately abutted frame rail by pivoting the lever 51 outwardly from the plane of the paneling 17. The subsequent pivoting of the operating lever downward and towards the plane of the wall panel will pull the locking bar 65 tightly into the locking slot 31 and will firmly and rigidly clamp the abutted frame rails, one to the other, between the locking bar and the fulcrum bar. As a very important aspect of the invention, each pair of abutted, clamped, hollow tubular rails constitutes a very strong (but light weight) load-bearing member, i.e., the four pairs of horizontal rails act as four loadbearing beams, while the four pairs of vertical rails act as four load-bearing columns. This the structures 10 may be readily, safely stacked upon one another or otherwise externally loaded or stressed.

In accordance with the invention, the keeper member is fabricated of tempered spring steel and is provided to maintain the toggle clamp assembly in permanent association with the wall sections and to maintain the elements of the assembly 50 in either of two positions shown in FIGS. 3 and 4. More specifically, the keeper includes a groove-like portion 71 which cooperates with the groove 30 on the frame rail 19 to define a substantially closed passage in which the fulcrum rod 52 is disposed. As shown in FIG. 4, the keeper member 70 is attached by rivets 73 or is otherwise suitably secured to the wall section to maintain the assembly 50 in a fixed longitudinal position with respect to each frame rail but in a manner which accommodates free swinging of the lever 51 and locking member 62 toward and away from the plane of the wall panel. Additionally, the keeper member includes an integral pair of U- shaped spring clip members 74, the inner surfaces 75 of which are adapted to engage and hold the operating lever 51 substantially flat against the wall panel, and the outer surfaces 76 of which are adapted to hold the locking member 62 parallel to the plane of the wall panel, as shown in FIG. 3. Accordingly, when the toggle clamp assembly 50 is not in use, it will be held restrained from movement and maintained in a recessed relation beneath the outer periphery of the wall section (the plane defined by the outer surfaces of the frame rails). On the other hand, when the locking member 62 is disposed in a locking relation (FIG. 4), the inner surfaces of the clips 74 will maintain the handle portion 55 of the lever against the wall panel, thereby securely maintaining the edge joint of the structure through the clamping of abutted wall sections and preventing the accidental unlatching of the locking member 62.

As a more specific aspect of the invention, each of the spring clips 74 may include an aperture 77 through which a sealing wire 78 may be threaded after the erection, filling, and closing of the structure 10, when it is used as a cargo container. The wire 78, when sealed across the gap between the clips 74 and over the handle 55 by an integral seal 79, will prevent unauthorized opening or tampering with the container and will provide further assurance against accidental unlatching of the locking member by pivoting of the lever 51.

As shown best in FIG. 4, the key 22 of the frame rail of one wall section nestingly or matingly fits into the mouth of the slot 31 of the frame rail of an adjacent wall section. The planar surfaces adjacent the key 22 abut the

lands

32, 33 adjacent the slot 31 in flat fact-toface contact, in a manner whereby the outer surfaces 42 of the frame rail members are disposed outwardly of the wall panels 17. These surfaces 42 are definitive of the outer periphery of the structure, as will be understood. In some applications, where it is desirable or necessary, an elastomeric sealing member or gasket 80 may be disposed in the bottom of the slot 31 to seal the formed container edge joint, which is, of course, rigidified and completed by clamping the nested frame rails together by the locking toggle action of the clamp assembly 50, described hereinabove. If desired, a gasketing elastomeric strip 81 may be fastened directly to the framing rail, as shown in FIG. 6. Thus it should be appreciated that, in accordance with the principles of the invention, an entire structure can be built up or knocked down in a matter of minutes without any tools merely by latching and unlatching a series of toggle clamps.

The sequence of erection of a complete parallelepiped is as follows: The bottom wall section 16 is disposed with the keys 22 of its frame 18 facing upwardly. The rear wall section 13 is then locked to the side wall section 12 in perpendicular relation thereto (with the key 22 and slot 31 nested in the manner shown in FIG. 4) by hooking the locking members carried by the rear wall section into the locking slot in the frame of the side wall section and then clamping the abutted frame rails together through the pivoting movement of the operating levers, thereby forming a corner post or loadbearing column of the container. Thereafter, the joined

sections

12, 13 may simply and accurately be located over the keys of the bottom wall section 16 and connected thereto by the locking members in a similar manner to that described immediately above. Subsequently, the side wall 14 is clamped to the rear wall and bottom wall. As should be understood, the wall sections l2, 14 will be free to abut the wall section 13, in spite of the upwardly facing keys 22 of the bottom wall section, due to the surface 41 of the corner connector which is recessed with respect to the keys 22. The structure 10 may be completed by clamping the front wall section to the bottom wall section 16 and to the end wall sections l2, l4, and then clamping the top wall section 15 to the interconnected upstanding wall sections 11-14 in the manner described.

While the above-described rectangular prism 10 represents one of the standardized configurations for intermodal (truck, ship, airplane, railroad car) cargo containers, the inventive concepts may also be employed in the manufacture of structures having shapes other than that of rectangular prisms. For example, cargo containers having the standardized A and B shapes established by the International Air Transport Association (IATA) may be readily built up from a series of wall sections comprising panels framed with the new hermaphroditic framing rails. Of course, and as will be understood, for special shapes the specific proportions and geometry of the cross section of the hermaphroditic rails may be suitably varied. However, the unique functional aspects of the hermaphroditic rail will be the same. For example, it may be desirable or necessary to fabricate a hermaphroditic rail 19 with an arcuate key 22', as shown in FIG. 5, rather than a wedge-shaped key 22, as shown in FIG. 2.

More specifically, utilizing the general principles of the present invention, a geodesic dome 84 (FIG. 8) may be built up from a plurality of

triangular panels

85, 86 framed with hermaphroditic framing rails 87 generally embodying the inventive concepts. As shown in FIG. 7, the rail 87 includes a shallow longitudinally extending groove 88 in which is seated the fulcrum rod portion 52 of a toggle clamp assembly 50 identical in construction and function to that described hereinabove. The framing rail 87 also includes a longitudinally extending locking slot 89 into which the hook 64 of the toggle clamp 50 may be inserted (as shown in FIG. 7) in the interlocking of

adjacent panels

85, 86. Actual mating of the edges of the rails 87 is effected through a longitudinal hermaphroditic groove 90, one wall of which groove is defined by a key member 91. Retained in the groove 90 is a flexible, resilient gasket 92, as shown. The rails 89 have outwardly extending

flanges

93, 94 which cooperate to define a channel 95 into which a sheet of paneling material 17 is inserted and held in the same manner described in connection with

flanges

27, 28 of the rails 19.

As shown in FIG. 7, the triangular panels may be easily and quickly connected to the panels 86 which surround it by operation of the toggle clamps 50 in the manner described hereinabove. As shown, the edge portions of the hermaphroditic rails 87 may be mated by the insertion of the rounded key members of adjacent rails into the hermaphroditic grooves 90. A tightly sealed joint is effected by the insertion of tightly sealed gaskets in each of the grooves of the abutted rails 87, as will be apparent from FIG. 7. In effect, the panels 85 will be righthanded and the panels 86 will be lefthanded. That is to say, the clamps on the panels 86 will be disposed internally of the dome 84, while the clamps on the panels 85 will be disposed externally of the panels. Thus, the orientations of the rails on

panels

85 and 86 are reversed. As shown in FIG. 7, the panel 86 has a toggle clamp 50 disposed internally of the dome, the hook of which clamp is engaged in the locking slot 89 of the panel 85, as shwon, while the clamp carried by the panel 85 is hooked into the locking slot of the panel 86 which is disposed externally of the structure. Thus, it will be appreciated that each of the righthanded triangular panels is locked to its neighboring lefthanded panel by latches extending in opposite directions and disposed on both sides of the completed edge joint of the dome 84.

In the aforementioned illustrated structure, a particularly advantageous lightweight sheet material 17, especially well suited for air cargo containers, comprises a 0.250 inch thick core of rigid, expanded plastic foam, e.g., polystyrene foam (Foamcore material commercially available from Monsanto Chemical) to the outer surface of which (outer is expressed in terms of the erected structure) is laminated a layer of 0.002 inch thick steel foil and to the inner surface of which is laminated a layer of 0.004 inch thick steel foil. Advantageously, a thin paper layer may be included between the foil and plastic foam in order to facilitate bonding of the foam to the foil and/or to enhance the strength of the laminated material. This very specific construction (0.002 inch of steel foil on the outside of a plastic core with 0.004 inch on the inside) offers substantial resistance to deleterious puncturing forces. Moreover, utilizing the same plastic foam core and the same total thickness of steel foil, foil arrangements other than the aforementioned 0.002 outside 0.004 inside do not provide the same high degree of punctureproofness. For example, 0.003 inch foil on both sides of the core is not as effective as the 0.002 inch outside-0.004 inch inside arrangement, nor is an arrangement of 0.004 foil on the outside and the 0.002 inch foil on the inside as effective.

It will be understood that the specific forms of the invention illustrated and described herein, including the frame rail and clamp assembly configurations, are intended to be representative only, and that certain changes may be made therein without departing from the clear teachings of the disclosure. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention.

I claim:

1. A universal, hollow one-piece hermaphroditic framing rail characterized in that the cross section of said rail includes four consecutive generally perpendicular walls, the first of which includes a key means, the second of which is adjacent to said first wall and includes a slot means abuttably matable with said key means, the third of which is generally flat, and the fourth of which has a paneling support means integral therewith.

2. A rail in accordance with claim 1, in which a. said key means is wedge-shaped and has a predetermined height,

b. said slot means is canted and has a depth greater than said predetermined height,

c. whereby the key means of one frame rail is adapted to nest in the slot means of another frame rail of the same cross section.

3. A lightweight collapsible geometric structure comprising a plurality of wall panels clamped together, characterized in that a. each of said panels is framed by universal hollow one-piece hermaphroditic framing rails having four sides, three of which are generally perpendicular;

b. all of said framing rails have key means and slot means of configurations abuttably matable with each other on consecutive sides, one of the other sides has panel support means formed integrally and recieving said wall panels; and

c. elastomeric gasket means are disposed between the key means and slot means of adjacent panels.

4. A universal, hollow one-piece hermaphroditic frame rail having a generally polygonal cross section including four sides, three of which are generally perpendicular, one of which sides includes a male key means, a second of which sides is adjacent to said first side and includes a separate female slot means of directly abuttably, matable configuration with said male key means, and panel retaining means formed integrally with a third side, said panel retaining means including an integral planar extension of a side remote of said slot means, whereby said universal frame rail is adapted to frame planar members of predetermined shape, a plurality of which framed panel members may be connected to one another in predetermined orientations in abutting edge-to-edge relationship with said key means and said slot means mated to establish predetermined three dimensional geometric structures.

Claims

2. A rail in accordance with claim 1, in which a. said key means is wedge-shaped and has a predetermined height, b. said slot means is canted and has a depth greater than said predetermined height, c. whereby the key means of one frame rail is adapted to nest in the slot means of another frame rail of the same cross section.

3. A lightweight collapsible geometric structure comprising a plurality of wall panels clamped together, characterized in that a. each of said panels is framed by universal hollow one-piece hermaphroditic framing rails having four sides, three of which are generally perpendicular; b. all of said framing rails have key means and slot means of configurations abuttably matable with each other on consecutive sides, one of the other sides has panel support means formed integrally and recieving said wall panels; and c. elastomeric gasket means are disposed between the key means and slot means of adjacent panels.