WO2021207786A1

WO2021207786A1 - A barrier

Info

Publication number: WO2021207786A1
Application number: PCT/AU2021/050302
Authority: WO
Inventors: Mark Found; Vadim Gershon; Desmond John Berry
Original assignee: Design Flow Pty Ltd
Priority date: 2020-04-15
Filing date: 2021-04-01
Publication date: 2021-10-21
Also published as: AU2021256325A1

Abstract

A barrier comprising a first post (3), a second post (5) and a stack (7). The stack spans from the first post to the second post and comprises one or more first members (9c) (each running about-horizontally), one or more stiffener members (11), (each running about-horizontally and stacked atop the one or more first members) and one or more second members (9d), each running about-horizontally, stacked atop the one or more first members and the one or more stiffener members.

Description

A BARRIER

FIELD OF THE INVENTION

The invention relates to barriers such as fences and retaining walls.

BACKGROUND TO THE INVENTION An existing approach to constructing one span of a barrier entails setting a pair of posts. Each of the posts has an I-beam profile and thereby defines a pair of channels opening in opposite directions. The two posts are oriented so that one channel of each post faces the other post. The posts may be set in concrete.

Sleepers running horizontally can then be dropped into the channels to form a stack of sleepers spanning from one of the posts to the other and so that one end of each sleeper is supported by one of the posts and the other end of each sleeper is supported by the other of the posts.

Often the sleepers are formed of treated pine. Concrete is another option. Concrete sleepers tend to be more durable and more aesthetically pleasing in use but are heavy and relatively brittle whereby transport to site and installation is difficult and typically entails wastage.

With the foregoing discussion in mind, the present invention aims to provide improvements in and for barriers, or at least to provide an alternative for those concerned with barriers and components therefor. It is not admitted that any of the information in this patent specification is common general knowledge, or that the person skilled in the art could be reasonably expected to ascertain or understand it, regard it as relevant or combine it in any way before the priority date. SUMMARY

One aspect of the invention provides a barrier comprising a first post; a second post; and a stack spanning from the first post to the second post and comprising one or more first members each running about-horizontally; one or more stiffener members, each running about-horizontally, stacked atop the one or more first members; and one or more second members, each running about-horizontally, stacked atop the one or more first members and the one or more stiffener members.

Preferably the one or more second members comprise one or more bottom projections arranged to be urged, against the one or more stiffening members, by load applied to the one or more second members and normal to the barrier. In some variants the one or more second members comprise one or more bottom projections arranged to be urged, against the one or more stiffening members, by load applied to the one or more second members in another direction normal to the barrier.

The one or more first members may comprise top projections arranged to be urged, against the one or more stiffening members, by load applied to the one or more first members and normal to the barrier; interspersed with the bottom projections.

Preferably at least one side of the one or more stiffener members is at least mostly concealed by one or both of the first members and the second members. More preferably both sides of the one or more stiffener members are at least mostly concealed by one or both of the first members and the second members. In some variants of the barrier, each member of the one or more second members comprises a front web a front of which defines a front presentation face; and rib portions, transverse to a length of the member, on a rear of the front web. In some other variants of the barrier, each member of the one or more second members comprises a front web a front of which defines a front presentation face on one side of the barrier; and a rear web a rear of which defines a rear presentation face on the other side of the barrier; and connecting portions connecting the front web to the rear web and running transversely to a length of a member.

As the wording is used herein, an Effective Density of a member is a ratio of a mass of the member to a volume of the smallest notional cuboid capable of containing the member. Preferably an Effective Density of one of the one or more stiffener members is at least twice an Effective Density of one of the one or more second members.

It is preferred that in situ a stiffness, normal to the barrier, of each of the one or more stiffener members is at least twice a stiffness, normal to the barrier, of each of the one or more second members. Optionally the one or more stiffener members bear on first bearing portions, of the one or more first members, and on second bearing portions of the one or more second members to define a first-to-second vertical spacing from the first bearing portions to the second bearing portions; the one or more second members bear on stiffener bearing portions of the one or more stiffener members, and are capable of bearing, on second stiffener bearing portions of one or more second stiffener members stacked on the one or more second members, to define a stiffener-to-second-stiffener vertical spacing of the stiffener bearing portions from the second stiffener bearing portions; and the stiffener-to-further-stiffener vertical spacing is at least twice, e.g. at least three times, the first-to-second vertical spacing.

Optionally each of the one or more second members is at least predominantly plastic and/or is an integral body of material. Preferably one of the one or more first members is substantially identical to one of the one or more second members. Preferably one of the second members runs from the first post to the second post.

The one or more of the stiffener members may comprise a stiffener member running from the first post to the second post. Preferably, each of the one or more stiffener members is at least predominantly metallic. The one or more stiffener members may each have a length and a substantially uniform profile along the length. The profile may be rectangular and/or hollow.

Preferably each of the first post and the second post defines an upright channel opening towards the other one of the first post and the second post and holding an end of the span. The barrier may be a fence. Alternatively, it may be a retaining wall.

One aspect of the invention provides a member for a barrier; the barrier comprising a stack of member-stiffener combinations substantially identical to each other; one of the member-stiffener combinations comprising the member and a stiffener stacked on the member; the member comprising a front web a front of which defines a front presentation face; one or more stiffener supports (e.g. a top flange) to bear against the stiffener of the one of the member-stiffener combinations; one or more member supports (e.g. a bottom flange) to bear against an underlying one of the member-stiffener combinations; one or more top projections projecting upwardly to sit behind the stiffener of the one of the member-stiffener combinations; one or more bottom projections projecting downwardly to sit behind a stiffener of the underlying one of the member-stiffener combinations.

Optionally there is a plurality of the top projections mutually spaced along a length of the member. A plurality of the bottom projections may be mutually spaced along the length of the member. Optionally the bottom projections are positioned to be interspersed with the top projections of the underlying one of the member-stiffener combinations.

Preferably the member comprises rib portions, transverse to a length of the member, on a rear of the front web.

The member may be shaped to be stacked directly on an underlying member identical to the member; carry an overlying member, identical to the member, stacked directly on the member; define bottom voids into which top projections of the underlying member extend upwardly beyond a bottom of the bottom flange; and define top voids into which bottom projections of the overlying member extend downwardly beyond a top of the top flange.

Another aspect of the invention provides a member for a barrier; the barrier comprising a stack of member-stiffener combinations substantially identical to each other; one of the member-stiffener combinations comprising the member and a stiffener stacked on the member; the member comprising a front web a front of which defines a front presentation face for one side of the barrier; and a rear web a rear of which defines a rear presentation face for the other side of the barrier; and top projections projecting upwardly to sit in front of and behind the stiffener of the one of the member-stiffener combinations; bottom projections projecting downwardly to sit in front of and behind a stiffener of the underlying one of the member-stiffener combinations.

Preferably, connecting portions connect the front web to the rear web and run transversely to a length of a member.

Preferably the top projections and the bottom projections are configured to at least mostly conceal the stiffeners of the barrier.

The member may be at least predominantly plastic, an integral body of material and/or at least twice (e.g. at least four times) as long as a height of the member.

Another aspect of the invention a member for a barrier; the barrier comprising a stack of member-stiffener combinations substantially identical to each other; one of the member-stiffener combinations comprising the member and a stiffener stacked on the member; the member comprising a front web a front of which defines a front presentation face; rib portions, transverse to a length of the member, on a rear of the front web; a top flange to bear against the stiffener of the one of the member-stiffener combinations; a bottom flange to bear against an underlying one of the member-stiffener combinations; one or more top projections projecting upwardly to sit behind the stiffener of the one of the member-stiffener combinations; one or more bottom projections projecting downwardly to sit behind a stiffener of the underlying one of the member-stiffener combinations; wherein the member is an integral body of plastic at least twice as long as a height of the member.

Another aspect of the invention provides a method, of constructing a barrier, comprising stacking members and at least one stiffener to form a stack, of about- horizontal members, spanning from a first post to a second post.

Another aspect of the invention provides a method of making a member.

Another aspect of the invention provides a barrier comprising a first post; a second post; and a stack spanning from the first post to the second post and comprising one or more first members each running about-horizontally; one or more stiffener members, each running about-horizontally, stacked atop the one or more first members; and one or more second members, each running about-horizontally, stacked atop the one or more first members and the one or more stiffener members. wherein the one or more second members comprise one or more bottom projections arranged to be urged, against the one or more stiffening members, by load applied to the one or more second members and in a direction normal to the barrier; one or more bottom projections arranged to be urged, against the one or more stiffening members, by load applied to the one or more second members in another direction normal to the barrier; one or more top projections arranged to be urged, against one or more overlying stiffening members, by load applied to the one or more second members and in the direction normal to the barrier; one or more top projections arranged to be urged, against the one or more overlying stiffening members, by load applied to the one or more second members in the other direction normal to the barrier; a front web a front of which defines a front presentation face on one side of the barrier; and a rear web a rear of which defines a rear presentation face on the other side of the barrier; and each of the first post and the second post defines an upright channel opening towards the other one of the first post and the second post and holding an end of the span.

BRIEF DESCRIPTION OF DRAWINGS Figure 1 is a top perspective view of a fence sleeper;

Figure 2 is a top view of the fence sleeper of Figure 1 ;

Figure 3 is a bottom view of the fence sleeper of Figure 1 ;

Figure 4 is a section view corresponding to the line A-A in Figure 2;

Figure 5 is a bottom perspective view of a portion of the fence sleeper of Figure 4; Figure 6 is a perspective view of a barrier;

Figure 7 is a vertical transverse cross section view of a portion of the barrier of Figure 5;

Figure 8 is a rear perspective view of a retaining wall sleeper;

Figure 9 is an enlargement of a portion of Figure 8; Figure 10 is a transverse vertical cross section view of the sleeper of Figure 8;

Figure 11 is a front perspective cutaway view of a barrier;

Figure 12 is a rear perspective cutaway view of the barrier of Figure 11 ;

Figure 13 is an enlargement of detail C in Figure 12;

Figure 14 is a view corresponding to Figure 13 of an alternative barrier; Figure 15 is a perspective view of retaining wall sleepers stacked on a pellet;

Figures 16a, 16b, 16c are front views of ends of retaining wall sleepers;

Figure 17 is a rear view of a part ejected from a mold; and Figure 18 is an end view of the part of Figure 17. DESCRIPTION OF EMBODIMENTS

Figure 6 illustrates a barrier 1 comprising a first post 3, a second post 5 and a stack 7. The stack 7 comprises horizontally running members 9 interleaved with horizontally running stiffeners 11 (Figure 7). Each of the posts 3, 5 is an I-beam. The post 3 defines a channel 3a opening towards the post 5 whilst the post 5 defines a channel 5b opening towards the post 3. The members 9 and stiffeners 11 are alternately dropped into the channels 3a, 5b whereby the stack 7 spans from the post 3 to the post 5 and the ends of the stack are supported by the posts 3a, 5b.

In this case there are four members 9a, 9b, 9c, 9d that are substantially identical to each other. Other barriers may comprise mutually-different members e.g. members 9b, 9d might be taller than members 9a, 9c and/or have a different colour to create a different aesthetic.

The members 9 are horizontally supported by the stiffeners 11 and thereby may have a lighter weight construction. Preferred variants of the member have an Effective Density less than the density of treated pine. Preferably each member predominantly consists of a single integral body of material. For the avoidance of doubt, ‘integral’ and similar terminology is used herein in its conventional sense to refer to a single continuous body of material. As such, bodies may be integrated by welding but not by conventional mechanical fastening.

Figure 1 illustrates the member 9c, which member is about 2,400 mm long by about 200 mm high by about 80 mm horizontally deep. The member 9c is injection moulded. Other modes of construction are possible. By way of example, multiple pieces of plastic might be integrated by ultrasonic welding. Alternatively, the member might be a composite member formed of multiple integral members mechanically fastened to each other.

The member 9c is formed of recycled plastic (e.g. recycled polypropylene) or other suitable plastic. Whilst plastic is preferred, other materials may also be used. By way of example, each member 9 might have a lightweight metallic construction that is adequate when supported by stiffeners 11.

Each stiffener 11 is preferably metallic. By way of example, the stiffeners might be formed of steel. Preferably the member 11 is corrosion resistant, e.g. the member may be formed of an inherently corrosion resistant alloy and/or be equipped with a suitable coating such as a zinc based surface coating for resisting corrosion. In this example, the stiffener 11 is 35 mm by 65 mm tube steel. Rectangular (e.g. square) profiles are preferred although other shapes are possible. 50 mm x 25 mm is another convenient size. There are other options, e.g. the stiffeners might be pultrusions.

Typically, it is most convenient for each of the stiffeners 11 within a given barrier to be substantially identical to each other, although there are other options. By way of example, in the context of tall retaining wall, the stiffeners closer to the base of the wall may be heavier for improved load bearing.

The member 9c comprises a front web 13 and a serpentine structure 17 running along the length of the member 9c and mutually connecting the webs 13, 15. The structure 17 is a continuous web comprises a repeating pattern of inclined connecting portions 19, stiffener supports 21 and member supports 23. The connecting portions 19 are transverse to a length of the member 9c and mutually connect the webs 13, 15. In this case the connecting portions 19 are alternately inclined relative to the length of the member 9c to be conveniently cored from above and below. In other variants, the connecting portions might be substantially vertical.

In this example, the serpentine structure 17 is about 5 mm thick. A rib 25 runs along (e.g. centrally along) the length of the serpentine structure 17 and serves as a flow leader for distributing plastic during injection moulding. In this example, the rib 25 is about 5 mm high by about 10 mm wide.

Preferably the rib 25 runs along a bottom of the stiffener supporting portions 21 and along the top of the connecting portions 19 and the member supporting portions 23. Preferably the stiffener supporting portions 21 upwardly present co-planar horizontal surfaces, and the member supporting portions 23 downwardly present co-planar horizontal surfaces. That said, in some other variants of the member 9c, the portions 21 , 23 may be non-planar although preferably the stiffener supporting portions 21 sit in register with each and the member supporting portions 23 sit in register with each other.

In this example, the ends of the member 9c are capped by end walls 27.

A center of the member 9c, or more specifically one of the member support portions 23 in this case, is penetrated by an opening 29. In this case, the opening 29 is a rectangular opening. Contiguous extensions of the webs 13, 15 define top and bottom projections in the form of top flanges 13a, 15a and bottom flanges 13b, 15b.

The stiffener supporting portions 21 and top projections, in the form of top flanges 13a, 15a, define an upwardly open stiffener receiving recess 30 into which the stiffener 11 can be dropped. This recess is 17.5 mm deep, or to put it another way, the flanges 13a, 15a project 17.5 mm above the stiffener support portions 21. In this way, half of the stiffener 11 seats within the member 9c whilst the other half projects above.

The member 9d upwardly adjacent to the member 9c can then be stacked atop the member-stiffener combination 9c, 11. When the member 9d is dropped in place, it fits over the projecting top portion of the stiffener 11. It’s member support portions 23' bears against and rests upon the stiffener 11 and its bottom flanges 13b', 15b' project downwardly on either side of the stiffener 11 and, in this example, abut the flanges 13a, 15a along a continuous line of contact. The stiffener 11 is thereby fully enclosed within the members 9c, 9d and thereby is concealed from view. The recess 30 serves as a keyway and the stiffener 11 serves as a key keying the vertically adjacent members to each other.

The flanges 13a, 13b, 15a, 15b serve dual purposes:

• Firstly, they function as abutments for acting upon the sides of the stiffener 11. By way of example, with reference to Figure 7, if a wind loading urged the members 9c from right to left, the flanges 15a, 15b would be urged against the stiffener 11 whereby the stiffener 11 supports the member 9c against this loading normal to the plane of the fence.

• Secondly, the flanges conceal the stiffeners from view to improve the outward aesthetic of the fence.

In other variants a separate structure may be provided for each of these purposes, e.g. at each corner of the member’s profile a cosmetic flange might sit outwards from an abutment for abutting the stiffener.

Whilst in this example the top flanges 13a, 15a simply abut the vertically adjacent bottom flanges 13b’, 15b’, there are other options. In one advantageous implementation, the vertically adjacent flanges have complementary stepped profiles whereby the bottom flanges sit inside and mate with the vertically adjacent bottom flanges. In this way, the vertically adjacent members 9 are configured to mutually locate with respect to each other in the direction normal to the barrier. This helps to produce a more neatly aligned fence whilst leaving clearances within the fence posts and within the recesses 30 for rapid and convenient assembly. Other variants of the members 9 might be equipped with other mutually co-operable features to mutually align with respect to each other in a similar way.

Preferred variants of the member 9c are configured to be formed from a simple two- way split dye. Preferably, the member 9c is configured to be cored from above and below. One or more presentation surfaces of the member 9c may have textural features. A two-way split dye may be employed to produce textural features transverse to the length of the member 9c. Alternatively, a four-way split dye may be employed to produce other shapes.

In some contexts, e.g. in connection with shorter spans, the members 9 might simply be stacked directly one atop the other. In this case the stiffeners 11 might not be called for. For such purposes, the opening 29 provides an alternative means for mutually connecting the vertically adjacent members 9 and stiffening the stack 7. The openings 29 of the stack 7 sit in register to be skewered by a vertical member, which member may be formed of similar materials to the stiffeners 11. By way of example, the vertical member might be formed of 30 mm by 30 mm tube steel. Alternately, the vertical member may have a circular profile (or other convenient profile). Preferably the opening 29 has substantially the same shape as the profile of the vertical member. Optionally, plural openings 29, e.g. three openings 29, may be spaced along the length of the member.

The openings 29 may be as-molded features and/or formed by one or more post molding material-removal operations. In a preferred implementation each opening 29 as molded is spanned by a respective flow leading portion (a respective portion of the rib 15 in this case) and the respective flow leading portions are cut out. The material removal operation may occur prior to shipment to the consumer or be left as an optional operation for onsite workers.

Conveniently, plumbing and/or power may be routed along a void defined by a vertically adjacent two of the members 9. This routing may be instead of or in addition to a stiffener 11. The routing may be within a stiffener. For this purpose the stiffener may be formed of C-section or other open profile.

To suit such shorter spans, shorter variants of the members 9 may be provided. Alternatively, the members 9 might be cut to length, e.g. cut to length on site. Cutting injection moulded plastic is straightforward relative to cutting concrete. Most home handy people will have access to a saw (e.g. a handsaw intended for cutting timber) well adapted to cutting plastic. In contrast, cutting concrete typically calls for more specialised equipment. Spans longer than each member 9 can also be formed. Most preferably, individual stiffeners each long enough to span from post to post are employed whilst lightweight members are laid end to end to complete the span. By way of example, as noted above the member 9c is about 2,400 mm long; a 3,600 mm span may be installed by connecting a member 9c end to end with a half-length of member 9c, stacking a 3,600 mm stiffener atop these two members and then repeating the operation. Preferably the members are laid, e.g. in a brickwork pattern, to horizontally space the junctures, of members connected end-to-end, from similar junctures of neighbouring layers.

Likewise, it is also possible to build up barriers in which the stiffeners run less than the full length of the span. By way of example, a stiffener might simply be positioned at mid span, where the bending moment is greatest. Optionally, separate stiffener members might be laid end to end. Again, it is preferred that the junctures between the end to end members do not align with similar junctures in other layers - e.g. a brickwork pattern may be convenient.

The wall 1 is equipped with a cover strip 31 that sits within the stiffener receiving recess of the uppermost of the members 9 to give the wall 1 an attractive finished look.

Figure 6 shows a barrier 1 comprising one span between two posts. Of course, longer barriers comprising multiple spans are possible, e.g. an end of another stack, e.g. substantially identical to the stack 7, might be supported within the channel 5a of the post 5.

In this example, the 35 mm high stiffener 11 defines a member-to-member spacing between the operative faces of the portions 21 , 23' of 35 mm. The operative faces of the portions 21 , 23 define a stiffener-to-stiffener spacing of about 165 mm whereby a stacking pitch of the member-stiffener combination 9, 11 is about 200 mm. In this example, the member support portion 23' bears on the stiffener 11. Other variants may do without the support portion 23'. Instead, each of the upwardly adjacent members may rest on the underlying member rather than on the stiffener 11. Preferably the top flanges 13a, 15a project about half of the member-to-member spacing above the stiffener supporting portions 21, and the flanges 13b, 15b project about half the member-to-member spacing below the member supporting portions 23, to hide the stiffeners.

The member 9c is well suited to barriers such as neighbourhood fences. In particular, advantageous variants of the member 9c are substantially identical on each side and in turn the barrier 1 is substantially identical on each side thereby avoiding neighbourhood disputes as to which neighbour should be faced with a side of the barrier thought to be less desirable than the other.

Other variants are possible. For example, asymmetric variants are possible. In particular, whereas the member 9c incorporates load transmitting abutments (in the form of flanges 13a, 13b) by which the member 9c draws support from the stiffener in one direction and load transmitting abutments (in the form of flanges 15a, 15b) by which the member 9c draws support from the stiffener 11 in the other direction,

Figure 8 illustrates a member 33 adapted to draw support from stiffeners in one direction normal to the barrier and draw minimal support from the stiffeners in the other direction. The member 33 is well adapted for producing retaining walls such as the barrier 35 (Figure 11 ).

The member 33 has many similarities to the member 9c. Each of these members may incorporate features described in respect of the other. Likewise each of the barriers 1 , 35 may incorporate features described in respect of the other.

The member 33 is a single integral body of plastic comprising a front web 37, a top flange 39, a bottom flange 41 , top projections 43 and bottom projections 45. The portions 37, 39, 41 , 43, 45 have a wall thickness of about 6 mm. The front web 37 is about 2,400 mm long by about 200 mm high. Ribs 47 are spaced at a pitch of about 70 mm along the rear of the front web 37. In this example each rib 47 is a vertical rib and has a profile of about 20 mm by 6 mm. The junctures of the ribs 47 and the flanges 39, 41 are radiused.

The top flange 39 runs along the full length of the member 33 and extends rearwardly by an amount complementary to the stiffener 11 to define an upwardly directed stiffness support portion. In this case the flange 39 presents a planar far 49 to the stiffener.

Top projections 43 sit rearward of the stiffener support portion 49 and project upwardly from the flange, in this case upwardly from a rear of the flange to sit behind the stiffener 11 as best illustrated in Figure 13. In this way, a front presentation surface 51 of the front web 37 sits substantially in register with front surfaces of the stiffener 11 whereby a front 53 (Figure 11) of the barrier 35 is substantially planar.

Along a bottom of the member 33 the bottom flange 41 defines a downwardly directed member support surface, akin to the surface 49, for bearing on a top of the stiffener 11 ; and the bottom projections 45 extend downwardly from the bottom flange 41 behind the surface 45 to sit behind the stiffener 11.

In this way, the projections 43, 45 sit behind the stiffener 11 to bear against the stiffener and thereby support the members 33 to resist load applied to the members 33 from behind the wall 35, e.g. to assist the members 33 to resist the bearing pressure of earth retained behind the wall 35.

Advantageously, the size of the stiffener 11 can be varied to suit the loading requirements. Figure 13 illustrates a 35 mm x 65 mm rectangular hollow section (RFIS) that may be usefully applied lower down in the retain wall and/or in the context of longer spans. 50 mm x 25 mm RFIS is another convenient size. Figure 14 illustrates an alternate variant in which a stiffener 11 ' in the form of a 65 mm x 5 mm steel plate sits between member 33 and the overlying member 33'. For this purpose, the projections 43, 45 have mutually complementary spacings offset from each other so that they can interleave behind thinner stiffener members. Furthermore, the top projections 43 sit behind the bearing surface 49 (and the bottom projections 45 likewise sit behind the bearing surface 55) to define top voids 57 (and bottom voids 59; see Figure 9). In this example, the flanges 39, 41 are coincident with the bearing surfaces 49, 55 whereby the voids 57, 59 are rearwardly open notches although, in principle, the voids 57, 59 might take the form of through holes through longer flanges that extend further rearwards. Stiffener profiles other than RHS and plate are possible. By way of example, a channel section may be employed. Roll forming is a convenient mode of construction. A corrosion-resistant metallic material e.g. galvanised steel, is preferred. A range of profiles of differing material thicknesses may be offered to suit differing reinforcement requirements. By way of example, a range of 50 mm x 10 mm channel sections formed of galvanised steel having thicknesses of 0.5 mm, 1.2 mm and 2 mm may be provided.

As best illustrated in Figure 14, the top voids 57 are positioned to receive the bottom projections 45 of the overlying member 33' whilst the bottom voids 59 of the overlying member 33' are arranged to receive the top projections 43 of the member 33. In this way large (e.g. about 15 mm high) top and bottom projections can be provided to securely engage the rear of the stiffener 11 whilst the member 33 is adapted to co operate with thin stiffeners 11 , or indeed to simply co-operate with a vertically adjacent member without any intervening stiffener at all. By way of example, in the context of a short span at the top of a retaining wall, a stiffener might not be called for.

Advantageously thin stiffeners 11 are sandwiched between the bearing surfaces 49, 55 and supported thereby so as to resist buckling. In this way, the lateral stiffness of the member 11 in situ can be greater than the stiffness of a similar member that is unsupported.

The thin walled construction of the member 33 and in particular the thin wall construction in combination with the ribs 47 transverse to the length of the member, produces a lightweight member that is cost efficient to produce and easy to transport and install. In particular not only is the member lighter (and therefore less costly to freight and safer to manually handle) it also packs more efficiently than a typical cuboid sleeper. As suggested in Figure 15 like members 33 can be interlocked for space efficient packing.

The members 9, 33 described herein may advantageously carry patterned ornamentation for improved aesthetics. Preferably these aesthetics comprise inherent properties of the material and/or features molded in to the material. Surface treatments such as painting are also possible. Figures 16a, 16b, 16c illustrate portions of retaining wall members 33a, 33b, 44c comprising presentation faces 51a, 51b, 51c in which aesthetic features are molded in. The presentation surface 51a comprises a foliage pattern; the presentation surface 51 b comprises a geometric pattern; and the presentation surface 51c presents as horizontally running boards. As described herein, the various members described herein may be stacked to form fences and retaining walls. Alternatively, they may be employed to clad an existing wall (or other surface).

The member 33c (Figure 16c) comprises top and bottom projections 43c, 45c, each of which is penetrated by a fastener-accommodating opening through which a fastener (e.g. screw) can be passed to fasten the member 33c to a wall. In one preferred mode of construction, a lowermost member 33c is fastened top and bottom to a wall. Thereafter, a subsequent member 33c can be placed so that its lower fingers 45c nest in behind the top flange of the lowermost member. This subsequent member 33c can then be placed so that its lowermost projections sit behind the lowermost member 33c whereby the subsequent member (and each subsequent member thereafter) need only be screwed off (or otherwise fastened) along its top edge to clad the wall.

Advantageously the fastener receiving openings are slotted, e.g. slotted in a lengthwise direction, to accommodate movement, e.g. expansion, relative to the backing surface.

The mutual staggering of the top and bottom projections allows substantially identical members to be stacked vertically one on top of the other to produce a straight stack.

Preferably a range of geometrically-similar but aesthetically different members is provided to allow for easy and convenient aesthetic effects. By way of example, a wall might be clad mostly with members 33c whilst a single horizontal row of the cladding is made up of members 33a as a feature line. Preferably the members are molded in multi-shot dyes. Figure 17 is a rearview of a portion from a four-shot dye for simultaneously producing four members 33c. As illustrated, a set of runners mutually connects an adjacent two members 33c.

Whilst various examples of various technologies are disclosed herein, the invention is not limited to these examples, e.g. whilst examples entailing members abutting the sides of cuboid stiffeners are disclosed, in other variants, this relationship might be reversed. A simple variant of a barrier might entail and H-section metallic stiffener co- operable with cuboid plastic members. Other variants might rely on friction and, whilst it is preferred that the key components can simply be stacked, load transmission within the stack might be enhanced by adhesive and/or mechanical fastening.

Posts other than I-beams are possible, e.g. the sleepers might have end flanges to sit fore and aft of the posts, in which case each post may have a convex (e.g. rectangular) profile. Preferably the sleepers can simply be dropped in place, although mechanical fasteners might connect the sleepers to the posts as an additional or alternative measure. In the context of a retaining wall, by way of example, the sleepers might sit behind the posts.

The term ‘comprises’ and its grammatical variants has a meaning that is determined by the context in which it appears. Accordingly, the term should not be interpreted exhaustively unless the context dictates so.

Claims

1. A barrier comprising a first post; a second post; and a stack spanning from the first post to the second post and comprising one or more first members each running about-horizontally; one or more stiffener members, each running about-horizontally, stacked atop the one or more first members; and one or more second members, each running about-horizontally, stacked atop the one or more first members and the one or more stiffener members; wherein the one or more first members comprise top projections spaced lengthwise along the one or more stiffener members to be urged, against the one or more stiffening members, by load applied to the one or more first members and normal to the barrier; and the one or more second members comprise bottom projections spaced lengthwise and interspersed with the top projections along the one or more stiffener members to be urged, against the one or more stiffening members, by load applied to the one or more second members and normal to the barrier.

2. The barrier of claim 1 wherein each member of the one or more second members comprises a front web a front of which defines a front presentation face; and rib portions, transverse to a length of the member, on a rear of the front web.

3. The barrier of claim 1 or 2 wherein an Effective Density of a member is a ratio of a mass of the member to a volume of the smallest notional cuboid capable of containing the member; and an Effective Density of one of the one or more stiffener members is at least twice an Effective Density of one of the one or more second members.

4. The barrier of any one of claims 1 to 3 wherein in situ a stiffness, normal to the barrier, of each of the one or more stiffener members is at least twice a stiffness, normal to the barrier, of each of the one or more second members.

5. The barrier of any one of claims 1 to 4 wherein the one or more stiffener members bear on first bearing portions, of the one or more first members, and on second bearing portions of the one or more second members to define a first-to-second vertical spacing from the first bearing portions to the second bearing portions; the one or more second members bear on stiffener bearing portions of the one or more stiffener members, and are capable of bearing, on second stiffener bearing portions of one or more second stiffener members stacked on the one or more second members, to define a stiffener-to-second-stiffener vertical spacing of the stiffener bearing portions from the second stiffener bearing portions; and the stiffener-to-further-stiffener vertical spacing is at least twice the first-to-second vertical spacing.

6. The barrier of any one of claims 1 to 5 wherein each of the one or more second members is at least predominantly plastic.

7. The barrier of any one of claims 1 to 6 wherein each member of the one or more second members is an integral body of material.

8. The barrier of any one of claims 1 to 7 wherein one of the one or more first members is substantially identical to one of the one or more second members.

9. The barrier of any one of claims 1 to 8 wherein the one or more of the stiffener members comprise a stiffener member running from the first post to the second post.

10. The barrier of any one of claims 1 to 9 wherein each of the one or more stiffener members is at least predominantly metallic.

11. The barrier of any one of claims 1 to 10 wherein the one or more stiffener members each have a length and a substantially uniform profile along the length.

12. The barrier of claim 11 wherein the profile is rectangular.

13. The barrier of claim 11 or 12 wherein the profile is hollow.

14. The barrier of any one of claims 1 to 13 wherein each of the first post and the second post defines an upright channel opening towards the other one of the first post and the second post and holding an end of the span.

15. The barrier of any one of claims 1 to 14 being a retaining wall.

16. A member for a barrier; the barrier comprising a stack of member-stiffener combinations substantially identical to each other; one of the member-stiffener combinations comprising the member and a stiffener stacked on the member; the member comprising a front web a front of which defines a front presentation face; one or more stiffener supports to bear against the stiffener of the one of the member-stiffener combinations; one or more member supports to bear against an underlying one of the member-stiffener combinations; top projections projecting upwardly to sit behind the stiffener of the one of the member-stiffener combinations and mutually spaced lengthwise along a length of the member; and bottom projections projecting downwardly to sit behind a stiffener of the underlying one of the member-stiffener combinations and mutually spaced along the length of the member to be interspersed with top projections of the underlying one of the member-stiffener combinations.

17. The member of claim 16 comprising a top flange to bear against the stiffener of the one of the member-stiffener combinations.

18. The member of claim 16 or 17 comprising a bottom flange to bear against an underlying one of the member-stiffener combinations.

19. The member of claim 16, 17 or 18 comprising rib portions, transverse to a length of the member, on a rear of the front web.

20. The member of any one of claims 16 to 19 wherein the member is shaped to be stacked directly on an underlying member identical to the member; carry an overlying member, identical to the member, stacked directly on the member; define bottom voids into which top projections of the underlying member extend upwardly beyond a bottom of the one or more member supports; and define top voids into which bottom projections of the overlying member extend downwardly beyond a top of the one or more stiffener supports.

21. The member of any one of claims 16 to 20 being at least predominantly plastic.

22. The member of any one of claims 16 to 21 being an integral body of material.

23. The member of any one of claims 16 to 22 being at least twice as long as a height of the member.

24. A method, of constructing a barrier, comprising stacking members and at least one stiffener to form a stack, of about-horizontal members, spanning from a first post to a second post; wherein each of one or more the members is in accordance with any one of claims 16 to 23.