GB2531553A

GB2531553A - Modular Tube and beam shelving system

Info

Publication number: GB2531553A
Application number: GB1418722.3A
Authority: GB
Inventors: Graham David
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-10-21
Filing date: 2014-10-21
Publication date: 2016-04-27
Also published as: GB201418722D0

Abstract

A load-bearing system comprises at least three spaced apart columns 2, at least one beam 1 having openings 5 through which the columns pass and a plurality of hollow sleeves 3 through which the columns pass, wherein the sleeves cannot pass through the openings in the beam and so act to support the beam. The columns preferably each comprise a hollow tubular pipe, preferably a tubular cardboard pipe and more preferably a spirally wound cardboard pipe. The sleeves may comprise tubular cardboard pipe. The beam may comprise a sheet material that may be formed into a hollow box section (1, figure 3) having an internal space. Collars 4 having a central bore through which a column passes are preferably located within the internal space to form part of the openings in the beam. The load-bearing system is preferably in the form of a shelving system comprising at least two beams, wherein the beams form shelves. Also disclosed is a kit for forming the load-bearing system of the invention.

Description

Modular tube and beam shelving system

Background of the invention

The present invention relates to a series of solid beams, or tubular beams folded from flat sheet, which grip a series of bisecting perpendicular tubular pipes and are held in place and kept spaced apart by a series of tightly fitting hollow pipe sleeves telescopically fitted over the tubular pipes within, holding the tubular beams squarely and securely in place. The present invention supports a wide range of structural possibilities including shelving, and the embodiment utilizing industrial corrugated cardboard and spiral wound cardboard tubes will be used to illustrate the present invention herein.

Low-cost furniture often has a relatively short lifespan. But the materials in its construction usually have a fairly long lifespan. This factor, combined with the variety of materials used in some furniture products makes environmentally responsible disposal problematic. The shift in emphasis for disposal toward recycling over landfill or incineration, coupled with impending governmental legislation increasing corporate disposal costs, means readily recyclable furniture is an increasingly attractive option.

Cardboard is an ideal material for recycling as it has an efficient and well-established infrastructure in place to process it. It is also cost-effective to recycle. The material has fascinated inventors for years, but creating low-cost furniture from it which has similar all-round performance to wooden, plastic or metal furniture has proved challenging. Coupled with this, the perceived problems of durability, structural integrity and surface fragility -with its connotations of flimsy packaging materials, have acted as a barrier to cardboard being taken seriously as a mono-material option for the mainstream high-volume furniture market.

Many attempts have been made to create strong, rigid cardboard furniture, usually collapsible furniture intended for temporary use. But any structural integrity gained by folding corrugated cardboard material to make legs or support structure is usually at the expense of appearance and ergonomics, rendering the furniture visually ungainly, or awkward to use compared to its more standard-material counterparts. One solution for cardboard-based low-cost furniture has been to use a rigid honeycomb cardboard sandwich composite to create tabletops, which has strength, hardwearing waterproof surfaces and a slim profile. Another has been to locate cardboard tubes into molded plastic sockets with metal fittings to create structures for furniture such as folding chairs US applicationl2/800,208. Whilst these uses of cardboard in furniture can create products that are generally fit for purpose, they are not readily recyclable, due to the mixed materials involved, thus losing this main advantage of the material.

The present invention offers a versatile modular tube and beam system, which can be employed in many instances where a number of load bearing horizontal platforms arranged vertically in series is required. The system supports the creation of strong, light, industrial cardboard shelving, which can match wooden, plastic or metal shelving in general performance, and facilitate simple, stylish, shelving design. The heavy gauge paper used in industrial corrugated board can be treated to provide acceptable furniture-like surface performance whilst maintaining full repulpability. This means furniture of balanced proportion and an aesthetic quality in keeping with expectations of the domestic and commercial shelving market can be produced with a surface of similar durability to the softwood from which the industrial cardboard is made.

Shelving systems which support a series of horizontal parallel surfaces using bisecting tubular members are widely known in the art, as disclosed in, CA2817485A1(1), DE3206278A1, DE4219852A1, DE19647639A1(1), DE19822614A1(1), GB247604A, GB190612539A, US4138953A, US5127342A, as are structural joints in the shelving, where the tubular members pass through and support the horizontal parallel surfaces and may fit inside each other telescopically, to provide a strong union, as disclosed in GB2232344A, DE3933739A1, GB1096727A, GB2109671A, US6241108B1.

Cardboard shelving using cardboard tubes utilized for structural purposes is also widely known in the art, as disclosed in DE19839414 (A1) The specific embodiment of the present invention which utilizes cardboard materials features a plurality of tubular cardboard beams, which grip a series of bisecting perpendicular tubular pipes and are held spaced apart by a plurality of tightly fitting hollow sleeves, holding the tubular cardboard beams squarely and securely in place. The tubular cardboard beams are folded and secured together each using two cardboard securing clips which are inserted into the two open ends of the beam, and the tubular pipes pass through the circular openings located on the surface of the tubular beam followed by the shorter and longer hollow pipe sleeves which support the structure and provide a tight interference fit, and stable, rigid structure.

GB2232344A discloses a shelving arrangement, which has a number of shelves on vertical supports, each one split into a lower and higher element in the region of the shelf. One of these elements has an end portion of reduced diameter, which fits inside the tubular end of the other part. The shelf has a greater diameter than the portion of reduced diameter, but lesser diameter than the outer diameter of the other element.

GB 1096727 discloses a shelving system built up from units each consisting of a platform and four tubular uprights each having an upper part of greater diameter connected to a lower part by a conical neck, the part of each upright being a force fit in the part of the upright next below. The edges of the platforms are U-shape having aligned apertures, the larger funnel-shaped aperture receiving the tubular uprights in such a way that each platform is clamped between the neck of one upright and the top of the upright next below.

DE19839414A1(1) discloses a cardboard shelving system consisting of bow-shaped side elements which stand vertically, held at a distance by horizontally positioned round cardboard bars, which are inserted into openings within the side elements. The kidney-shaped shelves, fitted with bow shaped slots are attached by sliding them onto the side elements from above. The straight back is also guided through matching slots at the back of the shelves from above.

Summary of Invention

In the first aspect, the present invention provides a modular system comprising of horizontal beams held in place by bisecting perpendicular tubular pipes with telescopically fitted hollow sleeves. The system may have a variety of applications, one of which is particularly illustrated herein, namely the construction of strong, lightweight shelving, but the present invention could have many other applications and indeed can be used in many applications where a plurality of load bearing horizontal platforms arranged vertically in series, is required. It is an object of the present invention to provide a simple, rugged, easily assembled system consisting of two or more high-strength tubular cardboard beams and at least three perpendicular intersecting tubular pipes made substantially of cardboard, of sufficient strength and durability to cope with, for instance, the demands of everyday domestic or commercial furniture use.

It is another object of the present invention to provide a modular system consisting of four horizontal high-strength tubular cardboard beams and four perpendicular tubular pipes made substantially of cardboard which pass through circular openings in the four beam's adjacent corners; the beams being spaced apart and kept in place by a series of twelve slidable hollow tubular sleeves telescopically fitted around the tubular pipes, and the internal structure of the beams being supported by a series of twenty slidable hollow tubular sleeves telescopically fitted around the tubular pipes inside the structure of the beam, four of which serve as feet at the base of the four tubular pipes, to form a set of free-standing shelves.

It is yet another object of the present invention to provide a modular system consisting of four horizontal high-strength solid beams made of thick honey-comb cardboard or an alternative thick strong board material, and four perpendicular tubular pipes made substantially of cardboard which intersect and pass through the four beam's adjacent corners; the beams being spaced apart and kept in place by a series of twelve slidable hollow tubular sleeves telescopically fitted around the four tubular pipes, to form a set of free-standing shelves. In this embodiment, a set of four slidable hollow tubular sleeves telescopically fitted around the tubular pipes base of the shelving structure below the bottom shelf may also serve as feet for the set of freestanding shelves.

The embodiment of the present invention which features tubular beams is comprised of multiples of five different components; a tubular beam and its securing clips, a tubular pipe, and two different lengths of hollow tubular sleeve both of a similar larger diameter than the tubular pipe, allowing an interference fit when telescopically fitted over the tubular pipe.

The tubular beam can be constructed from a single sheet of corrugated cardboard folded back on itself, thereby forming a single rectangular beam with two internal sections. The beam may be assembled by folding and rolling each side of the beam up from two opposite sides of a sheet of cardboard and folding the ends of those two sides into the centre of the beam and securing them with two clips, one at each open end of the beam, each constructed from a single sheet of corrugated cardboard. (see FIG 3 below) The tubular pipe can be constructed from spiral wound industrial cardboard, as can the two different lengths of hollow pipe sleeve.

The tubular beam has two locating cut-out slots positioned adjacently along its centre line. When the flat sheet is folded back on itself to form the two compartments within the beam, the four tabs positioned on the ends of the opposite two edges of the flat sheet fit into the central locating cut-out slots, allowing the two edges of the flat sheet folded over at right angles to the outer surface of the beam to mate squarely against each other ready for securing clips to lock the beam together. A pair of locating slots formed from cut-outs in the sides of the two mating edges in the centre of the beam allow the securing clips to hold the beam squarely and firmly in position. Each securing clip also has its own cut-out locating slot positioned along its centre line, and when inserted flush against the inside of the beam on the side where the beam has its centre-join a rigid union is created. When the securing clips are fully inserted they are recessed from the open ends of the beam, disguising the mechanism that holds it together and the strong, central reinforcing rail that adds stiffness and rigidity to the beam. The assembled tubular beam has eight circular holes in its surfaces, four in the four adjacent corners of the upper surface of the beam and four in the four adjacent corners of the lower surface. In order to begin forming a shelving unit, the four tubular pipes are inserted through the circular holes in the assembled beam at right angles to its upper and lower surfaces forming a tight interference fit with the holes in the beam. Four of the shorter lengths of hollow pipe sleeve need to be inserted into the two open ends of the beam at this stage to brace the inside of the beam from getting crushed from a load applied the beam or others in the shelving system above it. The two securing clips both have semi-circular locating recesses, to help locate the hollow pipe sleeves line up with the circular holes in the upper and lower surfaces of the beam. The tubular pipe passing through the two circular holes in each corner of the beam forms a tight interference fit with the beam and a loose interference fit with short length hollow pipe sleeve which braces the hollow beam, and also the longer length of hollow pipe sleeve who's length which dictates the amount of space between each beam when forming the set of shelves. The longer lengths of hollow pipe sleeves can be slid over each of the four tubular pipes above the upper surface of the beam to create a dividing space between the beams, and further tubular beams can be added by inserting the four tubular pipes into the circular holes in the lower surface of a further beam, following the same procedure as before of inserting the four shorter lengths of hollow pipe sleeve into the two open ends of this second beam then forcing the four tubular pipes through the four holes in the lower surface of the beam, through the four shorter lengths of hollow pipe sleeve, and out of the circular holes on the upper surface of the second beam. This process can be repeated to create shelving sets of different number and height, the main limiting factor being the length of the tubular pipe. It is possible to use more than one length of tubular pipe per beam corner by staggering the joint. This is to make sure it is in the middle of one of the longer lengths of hollow pipe sleeve. It is possible to provide feet for the shelving assembly by interference fitting or gluing shorter lengths of hollow pipe sleeve to the prominent ends of the tubular pipe protruding from the lower surface of the lowest beam. If the shelving assembly needs to be lifted with a load on it, 'feet' made from shorter lengths of hollow pipe sleeve can also be glued on to the prominent ends of the tubular pipe protruding from the upper surface of the highest beam. In this embodiment, ideally single, unbroken lengths of tubular pipe need to be used for the entire height of the shelving assembly.

The embodiment which features a horizontal high-strength solid beams made of thick honey-comb cardboard or an alternative thick strong board material, is assembled on the same principle as the shelving system above, omitting the steps taken to assemble and brace the tubular beam with shorter lengths of hollow pipe sleeve, as the beams are solid, so do not require bracing.

The shorter lengths of hollow pipe sleeve function as feet only in this embodiment, but the longer lengths of hollow pipe sleeve fulfil an identical function.

The term "tubular" when applied to an object is not intended to imply that the object is limited to any particular cross section or that it necessarily has a uniform cross section along its length (although it preferably does) and a beam used in the kit of components of the present invention may have, in one embodiment, a rectangular cross section while the pipe may have a circular cross section.

The tubular pipe may be constructed from spiral or convolute wound cardboard or folded corrugated cardboard, and beam may be constructed of corrugated cardboard preferably of fairly deep section to increase stiffness, and ideally good quality industrial corrugated cardboard with heavy grade liners or similar material to support rigidity in the circular holes, allowing them to gain a good grip on the tubular pipe. All the components of the system may be coated or otherwise treated with a repulpable coating to provide tough water-resistant, but readily recyclable products. The tubular pipe may be otherwise wound with suitable hardwearing papers, again ideally supporting repulpability.

The surface of the tubular pipe member should be such that the pipe member both slides though the tight-fitting circular holes within the corners of the beam, without the surface tearing, and also provide a high level of friction once installed. Various materials are suitable for the construction of the tube pipe member, such as pure Kraft paper, or high performance board, and the surface can be wrapped in a suitable paper, such as vegetable parchment, or a treated, or coated paper. In one embodiment (see FIG 2), the tube pipe member needs a suitably robust, cleanable surface, such as vegetable parchment, to withstand the rigours of domestic or commercial use.

In one embodiment (see FIG 2) the shorter lengths of hollow pipe sleeve can be glued to the tubular pipe within and the pipe can be glued in to the beam union's circular hole sockets for a permanent fit if desired, thus increasing the load-bearing capacity of the upper surface of the beam and of the entire structure. This might be considered desirable (see FIG 2) in a professional environment such a shop or factory, where it may inadvertently be subjected to forces it was not designed to withstand. Ideally a repulpable adhesive should be used in order to leave the joints recyclability uncompromised.

The present invention may in some embodiments rely on the strength and quality of the corrugated cardboard the beams are made from and of the ability of that material to hold accurate folds, so critical in the correct alignment of the interlocking cut-outs and tabs.

The corrugated board for the tubular beams of the present inventions in some embodiments needs to be thick and strong in order to grip the tube pipe member, so ideally a thick pure Kraft industrial board may be required, such as, AA flute.

The flat corrugated cardboard parts of one embodiment (see FIG 9) of the present invention can be palletized and shipped flat or shipped partially assembled (see FIG 4) ready for display in retail outlet and ready for customers to pick up and carry out of the shop. Flat shipping is particularly relevant for air-freighting furniture or intercontinental shipping, where space is at a premium. As most countries of the world have at least one industrial cardboard factory and cardboard tube factory, the embodiment shown (see FIG 2) can be manufactured anywhere, avoiding the need for expensive transport.

The present invention supports the design of a durable, light and immensely strong range of embodiments utilizing industrial cardboard, designed to facilitate both ease of transport and simple assembly for the user.

One embodiment shown (see FIG 2) accurately mirrors modern trends in use for affordable furniture, and allows individuals and companies to use and discard the products as they see fit, without guilt or environmental penalty. And indeed, the invention, in this embodiment by nature of its design and materials, can be considered so inexpensive that the user can afford to treat it as disposable after its useful life is completed.

Whilst the embodiment shown (in FIG 2) can be extremely tough if constructed with the appropriate industrial cardboard materials, and able to offer years of service, it also may be readily recycled and provides a foolproof closed-loop end of life solution, all the more relevant given the often short lifespan of low-cost furniture.

The present embodiment offers a stylish, modern furniture solution focusing on inclusivity, real-world user behavior and minimal environmental impact throughout production, distribution and disposal.

Detailed Description of the Drawings

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 shows an exploded perspective view of a modular tube and beam shelving assembly featuring a series of hollow beams; Figure 2 shows a perspective view of a modular tube and beam shelving assembly featuring a series of hollow beams; Figure 3 shows a perspective view of an inverted hollow tubular beam that has been unfolded; Figure 4 shows a perspective view of an inverted assembled hollow tubular beam; Figure 5 shows an exploded perspective end view detail of an assembled hollow tubular beam, with tubular pipes and hollow pipe sleeves; Figure 6 shows a plan view of a detail of an assembled hollow tubular beam, with separate securing clip, tubular pipes and hollow pipe sleeves; Figure 7 shows an end view of an assembled hollow tubular beam, with tubular pipes and hollow pipe sleeves; Figure 8 shows a side view of a modular tube and beam shelving assembly featuring hollow beams.

Figure 9 shows a plan view of a flat blank of a hollow tubular beam with separate securing clips; Figure 10 shows a perspective view of a modular tube and beam shelving assembly featuring a series of solid beams.

Referring now to the drawings, the exploded perspective view (FIG 1) shows a modular tube and beam shelving assembly. The shelving assembly is comprised of four different main components; a tubular beam 1; a tubular pipe 2, a longer hollow pipe sleeve 3; and a shorter hollow pipe sleeve 4. The tubular beam 1 can be constructed from a single sheet of corrugated cardboard folded back on itself, to form a beam with two separate internal rectangular sections. The hollow beams 1 are preferably made of double-wall industrial corrugated cardboard or similar heavy-gauge corrugated cardboard, of the type used commonly for shipping heavy goods, such as engine blocks, and the tubular pipe 2, and hollow pipe sleeves 3 and 4 shown in this embodiment (FIG 1) may be a spiral wound industrial cardboard core, made from strong, high quality cardboard, such as high performance board.

A tight-fitting right-angle union may be achieved by passing the tubular pipes 2 through a series of circular openings 5 located toward the end of each beam on the higher and lower horizontal planes, achieving a tight interference fit.

The embodiment shown in FIG 1 shows a series of twelve longer hollow pipe sleeves 3, which slide over the four tubular pipes during assembly; the length of which determines the height of shelf space within the shelving assembly; and twenty shorter hollow pipe sleeves 4, which also slide over the four tubular pipes during assembly; but serve the function of supporting internal structure of the tubular beams, and acting as feet for the shelving assembly. Both shorter and longer hollow pipe sleeves create a tight interference fit with the tubular pipe within.

FIG 2 shows a perspective view fully assembled modular tube and beam shelving embodiment featuring tubular beams, shown exploded in FIG 1.

Turning now to the interlocking cut-outs and tabs shown on the inverted and pre-assembled beam FIG 3, which shows a partially folded beam with two locating cutout slots 6 positioned adjacently along its longitudinal centre-line and four tabs 7 positioned on the ends of the opposite two edges of the pre-assembled sheet. When the flat sheet is folded back on itself to form the two compartments within the beam, the four tabs 7 positioned on the ends of the opposite two edges of the flat sheet fit into the locating slots 6, allowing the two edges of the flat sheet folded over at right angles to the outer surface of the beam to mate squarely against each other ready for securing clips 8 to lock the beam together. A pair of locating slots 9 formed from cut-outs in the sides of the two mating edges at the two ends of the central reinforcing rail 10 in the centre of the beam, allow the securing clips to hold the beam squarely and firmly in position. Each securing clip 8 has its own cut-out locating slot 11 positioned along its centre line, and when inserted flush against the inside of the beam on the side where the beam has its centre-join, a rigid union is created.

Turning now to FIG 4 which shows a perspective view of an inverted assembled hollow tubular beam. A securing clip 8, is inserted flush against the inside of each the ends of the beam, to engage with the corresponding locating cut-outs in the sides of the two mating edges in the centre of the beam.

Turning now to FIG 5, it will be observed the beam is now the in the correct orientation, as assembly of the beam in it's inverted position has been completed. Figure 5 shows an exploded perspective end view detail of the assembled tubular beam, with a securing clip 8 in the correct position inside the lower surface of the beam locking the two halves of the central reinforcing rail 10 and two tabs 7 visible through the locating cut-out slots 6 positioned along the beam's longitudinal centreline.

Looking at the next stage in assembly now the tubular beam is completed, FIG 5 shows two of the shorter lengths of hollow pipe 4 in position to be inserted into the open end of the beam to mate with the semi-circular cut-outs 12 in the end of the securing clip 8. Once in position the tubular pipes can be forced through the circular openings 5 in the beam, through the shorter lengths of hollow pipe 4 within the ends of the beam and then through the longer lengths of hollow pipe 3 above to form a tight interference fit.

Turning now to FIG 6, which shows a plan view of a detail of an assembled hollow tubular beam 1, with separate securing clip 8; the position of the inserted securing clip within the end of the beam can be seen represented in a dashed line within the end of the beam. The two tabs7 are also visible through the locating cut-out slot 6 positioned along the longitudinal centre-line of the beam and the central reinforcing rail 10 can be seen represented by a dashed line. The tubular pipes 2 and hollow pipe sleeves 3 can also be seen end-on, in their assembled positions.

Turning now to FIG 7, which shows an end view detail of an assembled hollow tubular beam 1 in the correct orientation with hollow pipe sleeves 3 and 4, and hollow pipe 2 within. The end of the central reinforcing rail 10, which runs along the centre of the beam along its most of its length and provides extra lateral strength to the beam can be seen, and the side of the securing clip 8 that holds the two separate halves of the central reinforcing rail together is also visible in this view.

Both the shorter 4 and longer 3 lengths of hollow pipe sleeve can also be seen in this view and the hollow pipe within is represented with a dashed line.

Turning now to Figure 8, which shows a side view of a modular tube and beam shelving assembly featuring tubular beams 1, the hollow pipe 2 can be seen represented by the innermost of the vertical dashed lines in two halves within the outer hollow pipe sleeves in this particular embodiment. The purpose of having two shorter hollow pipes, instead of one longer one passing through the circular openings in the corner of each tubular beam is two make the flat packed shelving system product easier to assemble and ship. The securing clips 8 can also be seen represented by a dashed line, as can the shorter lengths of hollow pipe sleeve 4, apart from the set beneath the lowest shelf, which act as 'feet' which are represented in solid line as they are in view and not enclosed within the tubular beams. The longer lengths of hollow pipe sleeve 3 can also be seen in this view.

Turning now to the flat blanks of the embodiment of the present invention which constitutes a light-weight shelving system, FIGS 9, shows flat blanks for the three separate components that make up a single hollow beam within the shelving system, Both the main body of the beam 1 and the two securing clips 8 that make up one shelf can be die-cut from a single flat sheet of corrugated cardboard. The hollow components of the tubular beams are preferably made of double-wall industrial corrugated cardboard or similar heavy-gauge corrugated cardboard.

The flat plan of the main body of the beam features four creases 13 represented by dotted lines, and two crease-cutsl4 shown as dashed lines which accurately represent a real crease-cut, to allow it to fold into the tubular beam. The creases 13 provide a gentle radius at 90 degrees, which is both aesthetically pleasing, and does not split the coloured waterproof finishes applied to the outer surface, and the crease-cut 14 provides a very accurate fold with less tension in the fold for very flat

I I

mating surfaces along the central re-enforcing rail. Although the necessary accuracy of the components could prove challenging for many cardboard factories, and the present invention supports all possible manufacturing options including rotary die-cutting, flat-bed die cutting.

All the features of the tubular beam and securing clips can be clearly seen on the flat blanks in FIG.9, including circular openings 5 which the tubular pipes pass through; locating cut-out slots 6; which receive tabs 7when folded; and can be seen on the ends of the two halves of the reinforcing rail 10; which features locating slots 9 to receive the securing clips8 when folded; which feature semi-circular cut-outs 12; and the securing clip's own locating cut outs 11.

Turning to figure 10, which shows a perspective view of a modular tube and beam shelving assembly featuring a series solid beams 15. In this embodiment the beams are constructed from a single thickness of thick honey-comb cardboard or an alternative thick strong board, in yet other embodiments, the beams could be constructed form multiple layers of thick honey-comb cardboard or an alternative thick strong board, should an increase in stiffness of the beams be required.

Many of the same features as the tubular beam shelving assembly shown in the exploded view in FIG.1 can be seen in FIG.10 including; a tubular pipe 2, a longer hollow pipe sleeve 3; and a shorter hollow pipe sleeve 4. The solid beam 15 also features circular openings 5 to allow tubular pipe 2 to pass through.

Claims

CLAIMS1. A load-bearing system comprising: at least three spaced apart columns; at least one beam, wherein each beam has openings and wherein the columns pass through different openings in the or each beam; and hollow sleeves through which the columns pass but said sleeves cannot pass through the openings in the at least one beam, thereby acting to support the at least one beam.
2. A load-bearing system as claimed in claim 1, wherein the sleeves have a top end and a bottom end and the top end of each sleeve engages a beam and the bottom end of each sleeve engages the surface on which the load-bearing system sits or a lower beam.
3. A load-bearing system as claimed in claim 1 or claim 2, which includes at least two beams and wherein the sleeves between the beams have a length of at least 5cm, optionally at least 8 cm, for example at least 12 cm.
4. A load-bearing system as claimed in any preceding claim, wherein the openings in the at least one beam form an interference fit with the columns.
5. A load-bearing system as claimed in any preceding claim, wherein the sleeves form an interference fit with the columns.
6. A load-bearing system as claimed in any preceding claim, wherein the columns each comprise a hollow tubular pipe, e.g. a tubular cardboard pipe, such as a spirally wound cardboard pipe.
7. A load-bearing system as claimed in any preceding claim, wherein the sleeves each comprise a tubular cardboard pipe, such as a spirally wound cardboard pipe.
8. A load-bearing system as claimed in any preceding claim, wherein the or each beam comprises a sheet material.
9. A load-bearing system as claimed in claim 8, wherein the or each beam is made of sheet material formed into a hollow box-section having an internal space.
10. A load-bearing system as claimed in claim 9, wherein the or each beam is formed of a single sheet folded to form the box-section.
11. A load-bearing system as claimed in claim 9 or claim 10, wherein each hollow box-section beam includes collars that are (a) located within the internal space of the beam, (b) form part of the openings in the beam and (c) have a central bore through which one of the columns passes.
12. A load-bearing system as claimed in claim 11, wherein the collars each have a height equal to the height of the internal space within the box section beam.
13. A load-bearing system as claimed in claim 11 or claim 12, wherein the central bore in each collar forms an interference fit with the column passing through it.
14. A load-bearing system as claimed in any one of claims 11 to 13, wherein the collars each have a cross section that is identical to the cross section of the sleeves.
15. A load-bearing system as claimed in any one of claims 8 to 14, wherein the sheet material from which the or each beam is made is cardboard.
16. A load-bearing system as claimed in claim 15, wherein the cardboard sheet material is corrugated cardboard.
17. A load-bearing system as claimed in any of claims 1 to 7, wherein the or each beam is formed of a single board.
18. A load-bearing system as claimed in claim 17, wherein the single board comprises a honeycomb cardboard panel or a section of wood, composite wood or a plastic material.
19. A load-bearing system as claimed in any of claims 1 to 7, wherein the or each beam is formed of a stack of sheets, e.g. cardboard sheets, which may be bonded together.
20. A load-bearing system as claimed in any preceding claim wherein the or each beam has a thickness of at least 10mm e.g. at least 20mm, for example at least 25mm and/or a thickness of not greater than 100mm, e.g. not greater than 60mm, for example not greater than 50mm.
21. A load-bearing system as claimed in any preceding claim wherein the columns, beams and sleeves are all composed substantially of cardboard.
22. A load-bearing system as claimed in any preceding claim, which includes 4 columns.
23. A load-bearing system as claimed in any preceding claim, which includes a sleeve located below the lowermost beam that supports the lowermost beam off the ground.
24. A load-bearing system as claimed in any preceding claim in the form of a shelving system comprising at least two beams and wherein the beams form the shelves of the shelving system.
25. A kit for making a load-bearing system, the kit comprising at least three columns, at least one beam and sleeves, wherein the kit can be assembled to form a load-bearing system as claimed in any preceding claim.