GB2126464A

GB2126464A - Portable of lightweight enclosures

Info

Publication number: GB2126464A
Application number: GB08320950A
Authority: GB
Inventors: Elliott Penton; David George Peter Stone
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-08-04
Filing date: 1983-08-03
Publication date: 1984-03-28
Also published as: WO1984000467A1; EP0118463A1; GB8320950D0

Abstract

A portable or lightweight enclosure has a flexible cover sheet (1) which is anchored to a base (2) or to the ground. A number of flexurally stressed or spring-loaded arched supports (6) are located within the cover sheet, the lower of the supports being free and braced against the inside of the cover sheet (1) by the stressing or loading of the supports so as to maintain the cover sheet in tension. The opposite longitudinal edges (5) of the sheet may be attached to respective longitudinal base members (3) which may be filled with ballast. The lower ends of the arched supports (6) may be interconnected by longitudinal elements (7) through which irrigation water may be supplied.

Description

SPECIFICATION Portable or lightweight enclosures This invention relates to portable or lightweight enclosures, more particularly enclosures of the kind in which a flexible cover sheet forms the sides and roof of an enclosure and is anchored along opposite sides to a base or to the ground. Such enclosures are commonly used in horticulture, for example as greenhouses, cloches or growing frames. In such enclosures the cover sheet is supported by arched frame members which are anchored at opposite ends to the base, the cover sheet being also anchored along opposite edges.

One of the disadvantages associated with such known enclosures is that the cover sheet is prone to expand, for example in hot or humid conditions, and lose its tension. This slackening of the cover sheet can result in tearing or fatiguing of the cover material, particularly if the enclosure is exposed to a high wind.

An object of the present invention is to provide a portable or lightweight enclosure having a cover sheet which is maintained in tension, notwithstanding expansion and contraction of the sheet material.

According to the present invention, in one aspect, there is provided a portable or lightweight enclosure comprising a flexible cover sheet anchored to a base or to the ground, and a number of flexurally stressed or springloaded arched supports located within the cover sheet, the lower ends of the supports being free and braced against the inside of the cover sheet by the stressing or loading of the supports so as to maintain the cover sheet in tension.

In another aspect the invention provides an enclosure having a cover sheet which is maintained in tension by a number of flexurally stressed or spring-loaded arched supports which are braced against the inside surface of the cover sheet, each support having at least one free end which is braced against a lower portion of the cover sheet, so as to maintain the latter in tension. The arched supports may have free lower ends while being anchored at their upper ends to a fixed support, thereby forming a lean-to enclosure.

The flexural stressing or spring-loading of the arched supports maintains the cover sheet in tension, by virtue of the fact that at least one end of each support is free. In the application of the invention to a portable freestanding enclosure the cover sheet may have opposite longitudinal edges which are attached to respective longituduinal base members, the arched supports being braced against the inside surface of the cover sheet between said longitudinal edges. The cover sheet may be releasably attached to the longitudinal base members, which may comprise hollow or tubular members which can be filled with water or other ballast upon assembly of the enclosure. The longitudinal base members may be maintained parallel to each other by transverse base members forming with the longitudinal members a rigid base frame.

In an alternative embodiment of the invention the cover sheet may be essentially tubular, having a lower portion on which the base rests, and an upper part, forming the roof and sides of the enclosure, which lies above the base and is tensioned by the flexural stressing or spring-loading of the arched supports.

The lower free ends of the arched supports are preferably interconnected by longitudinal elements which are urged against the inside surface of the cover sheet by the stressing or loading of the arched supports. At least one of the longitudinal elements and the arched supports are preferably tubular and intercommunicating, the arched supports having inwardly facing apertures which form sprinkler outlets for irrigation water supplied to the arched supports through one or both of the longitudinal elements.

The enclosure according to the invention has numerous practical applications. For example the cover sheet may be of clear plastics sheeting for application as a greenhouse, cloche or other horticultural enclosure.

Alternatively, the cover sheet may be of suitable weatherproof material and the enclosure used as a tent or shelter. As a shelter the enclosure may be used as a garage or workshop, or as temporary accommodation in disaster areas.

The invention will be further described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic perspective view of a portable enclosure according to one embodiment of the invention; Figure 2 is an end elevational view of the enclosure shown in Fig. 1; Figures 3-5 are perspective views illustrating successive stages in the assembly of the enclosure illustrated in Figs. 1 and 2; Figure 6 is an end elevational view, corresponding to Fig. 2, of an enclosure according to an alternative embodiment of the invention; Figure 7 is a perspective view, corresponding to Fig. 1, of the arched supports of an enclosure according to another embodiment of the invention;; Figures 8 and 9 illustrate two alternative forms of arched support for use in enclosures according to the invention, and Figure 10 is a perspective view illustrating a lightweight enclosure according to a further embodiment of the invention.

Throughout the drawings the same reference numerals are used to designate corresponding component parts of the illustrated embodiments.

The enclosure illustrated in Fig. 1 is a free standing enclosure for use as a greenhouse or other horticultural structure. The enclosure is essentially portable in that it can be dismantled and erected on any convenient horizontal ground, without the need for foundations.

The enclosure has a flexible cover sheet 1 of clear heavy duty polyethylene sheeting. The cover sheet 1 is essentially rectangular, being anchored along opposite longitudinal edges to a base 2. The base 2 in the illustrated embodiment comprises two hollow longitudinal base members 3 of square section plastics tubing which are interconnected and maintained parallel to each other by transverse base members 4, also of plastics material. The transverse base members 4 may be attached to the longitudinal base members 3 by.interlocking mortice and tenon joints, or any convenient interlocking formations, so that the longitudinal and transverse members 3, 4 form a rigid base frame, as illustrated in Fig.

3.

The longitudinal edges of the cover sheet 1 are releasably attached to the inside vertical faces of the two longitudinal square-section base members 3, as shown in Figs. 1 and 2.

The releasable attachment is preferably effected by means of multiple hook fastening strips 5, for example "VELCRO" tape, attached to the two longitudinal edges of the cover sheet 1 and anchored to cooperating strips on the laterally inwardly facing vertical faces of the two square section longitudinal base members 3. Any convenient form of releasable fastening may be used to attach the longitudinal edges of the cover sheet 1 to the base members 3. Alternatively, the longitudinal edges of the cover sheet 1 may be permanently attached to the longitudinal base members 3, for example by welding.

The width of the rectangular cover sheet 1 is such that it can form the sides and roof of the enclosure by adopting a tunnel shape of hyperbolic or parabolic cross-section between its two anchored longitudinal edges, as illustrated in Fig. 1. The cover sheet 1 is maintained in tension in this tunnel shape by a number of resiliently flexible arched Supports 6 which are located within the cover sheet 1.

The lower ends of the arched supports 6 are free in the sense that they are not attached to the base 2 but rather can "float" freely relative to the base 2. The supports 6 are normally straight, as shown in Fig. 5, and are flexurally stressed into their arched shape.

Since the supports 6 are in a state of flexural stress the free lower ends of the supports 6 are continuously urged outwardly by the stressing of the supports 6, thereby maintaining the cover sheet 1 in tension.

The flexible arched cover supports 6 are maintained parallel to each other by intercon nection, by connector pieces 8, of the opposite ends of the supports by longitudinal ele ments 7. As shown in Fig. 2, the cover sheet 1 is maintained in tension between its anchored longitudinal edges 3 and the longitudinal elements 7 interconnecting the lower ends of the arched supports 6. This tension is maintained throughout the cover sheet 1, irrespective of any stretching of the cover sheet, for example as a result of thermal expansion: any such stretching is accommodated by a sufficient outward movement of the lower ends of the stressed arched supports 6.

The longitudinal base members 3, as stated previously, comprise respective tubular members of square or rectangular cross-section of plastics material. These hollow members have sealing end caps 9 defining water-tight sealed containers which can be filled with water, sand, or other ballast through filler plugs 10 (Fig. 3) to weight the base 2 upon assembly.

To assemble and erect the enclosure the base 3 is first assembled from the longitudinal and transverse members 3, 4 (Fig. 3) and the hollow longiotudinal base members 3 are then ballasted, as described previously. The cover sheet 1 is then attached along its two longitudinal edges 5 to the laterally inwardly facing surfaces of the two longitudinal base members 3 (Fig. 4). The arched support structure is next assembled from the tubular supports 6 and the longitudinal elements 7, using the connector pieces 8 (Fig. 5). The assembled support structure is then deformed by bending of the tubular supports 6, and the deformed structure then inserted between the transverse base members 4 and the cover sheet 1.After full insertion of the support structure inside the cover sheet 1 the support structure is released, allowing the supports 6, now arched, to spring laterally outwardly under their flexural pre-stress until they are arrested by the cover sheet 1, which is thereby maintained in tension as described previously.

Once the tunnel shaped enclosure has been assembled and erected as described above, end closure panels may be added by clipping suitably shaped sheets of the same material as the cover sheet 1 to the arched supports 6 at opposite ends of the panel. Any suitable spring clip may be used for this purpose. The end closure panels may be divided vertically to form two flaps which can be secured to gether by releasable fastenings such as "VEL CRO" (Registered Trade Mark) fastenings.

Where the portable enclosure is intended for use as a greenhouse or other horticultural enclosure the arched supports 6 may conveni ently include tubular elements the walls of which are perforated by inwardly facing aper tures (not shown). These tubular elements communicate through the connector pieces 8 with the two longitudinal tubular elements 7, one or both of which may be connected to a source of irrigation water through a stop cock 11 (Fig. 1).

The use of hollow longitudinal base mem bers 3 has the further advantage that, when the enclosure is disassembled, the other component parts, including the cover sheet and the tubular elements 6, 7, may be stowed in the hollow interiors of the base members 3.

It is not essential that the cover sheet 1 be anchored to longitudinally extending base elements, as described with reference to Figs. 1 to 5. In an alternative embodiment, illustrated in Fig. 6, intended for use as a survival tent or shelter, the cover sheet 1 is essentially tubular and extends over the arched supports 6 and beneath a weighted base 2, which may be in the form of a sleeping bag or mattress and which takes the place of the base frame 3, 4 of the embodiment illustrated in Figs. 1 to 5. The flexural stress of the arched supports 6 maintains the cover sheet 1 in tension, as described previously, while the weighted base 2 effectively anchors the sheet to the ground.

For the erection of enclosures of substantial size the cover sheet 1 may consist of a number of sections joined together. In addition, the arched supports 6 may be interconnected at intervals by longitudinal bracing supports, in addition to the longitudinal elements 7 interconnecting the ends of the supports 6. Thus Fig. 7 illustrates a number of arched supports 6 each of which comprises two arcuate arms connected to a longitudinally extending ridge rod or tube 1 2 through spigot and socket connections. The lower ends of the arcuate arms are interconnected in pairs by respective rigid ties 1 3. The entire assembly of the resiliently flexible arched supports 6 and the ridge rod or tube 1 2 forms a skeletal frame which can be located within a cover sheet to tension the latter, as described previously.

In a further embodiment of the invention, not illustrated, the resiliently flexible arched supports 6 may be attached at an upper end to a fixed support, such as a vertical wall, and project laterally outwardly from this support.

The supports are bent into an arched shape in which they are maintained by the tension in the cover sheet, forming, in effect, a "lean to" enclosure. Such an enclosure would be useful as a shelter for decorators working on the outside of buildings.

It will be understood that the enclosure according to the invention can assume a number of different practical forms. For example, instead of the elongate tubular structure illustrated in the drawings, the enclosure may be a dome-shaped structure, with a flexible cover sheet which is anchored around its periphery by a water-filled or other suitably ballasted base. In this case the arched supports may be in the form of bracing struts which intersect at the apex of the dome structure, with "floating" circumferentially extending portions adjacent the anchored periphery of the cover sheet. Upon erection of the enclosure the cover sheet would assume a dome shape and would be maintained in tension by the flexural stress of the arched bracing struts, the enclosure having a shape similar to that of an 'igloo' or umbrella.

The internal bracing struts or arched supports 6 need not necessarily be tubular as in the illustrated embodiments: for some practical applications it may be found more practical to employ flat strips or bars of metal or plastics as the bracing struts. Moreover, the arched supports 6 need not necesarily be flexurally resilient. For example, as shown in Figs. 8 and 9 the supports 6 may comprise rigid arcuate arms 14, 15, hinged together about a pivot axis 1 6 extending longitudinally of the enclosure, and spring-loaded relatively to each other by a spring 1 7 so that the free lower ends of the arms 14, 1 5 are urged apart.

For some uses it may be desirable to anchor the base of the enclosure positively, in addition to, or as an alternative to, ballasting.

Thus the base may be anchored to the ground by bolts or stakes, for example where the enclosure is erected on sloping ground or in an exposed position.

Alternatively, and as illustrated in Fig. 10, opposite longitudinal margin flaps 1 8 of the cover sheet 1 may be turned inwardly towards each other and anchored directly to the ground by pins or stakes 1 9. The arcuate supports 6 may rest directly on the anchored margin flaps 18, the supports 6 tensioning the cover sheet 1 as described previously.

Claims

1. A portable or lightweight enclosure comprising a flexible cover sheet anchored to a base or to the ground, and a number of flexurally stressed or spring-loaded arched supports located within the cover sheet, the lower ends of the supports being free and braced against the inside of the cover sheet by the stressing or loading of the supports so as to maintain the cover sheet in tension.

2. An enclosure according to Claim 1, in which the cover sheet has opposite longitudinal edges which are attached to respective longitudinal base members, the arched supports being braced against the inside surface of the cover sheet between the said longitudinal edges.

3. An enclosure according to Claim 1, in which the cover sheet is releasably attached to the longitudinal base members.

4. An enclosure according to Claim 2 or Claim 3, in which the longitudinal base members are hollow or tubular members which can be filled with water or other ballast upon assembly of the enclosure.

5. An enclosure according to any one of Claims 2 to 4, in which the longitudinal base members are maintained parallel to each other by transverse base members forming with the longitudinal members a rigid base frame.

6. An enclosure according to any one of Claims 1 to 5, in which the lower free ends of the arched supports are interconnected by longitudinal elements which are urged against the inside surface of the cover sheet by the stressing or loading of the arched supports.

7. An enclosure according to Claim 1 or Claim 6, in which the cover sheet is essentially tubular, having a lower portion on which the base rests, and an upper part, forming the roof and sides of the enclosure, which lies above the base and is tensioned by the stressing or loading of the arched supports.

8. An enclosure according to Claim 6 or Claim 7, in which at least one of the longitudinal elements and the arched supports are tubular and intercommunicating, the arched supports having inwardly facing apertures which form sprinkler outlets for irrigation water supplied to the arched supports through one or both of the longitudinal elements.

9. An enclosure according to any one of the preceding claims, in which each arched support comprises two arcuate arms connected to a longitudinally extending ridge rod or tube interconnecting the arched supports.

10. An enclosure according to Claim 6, in which the lower ends of adjacent arched supports are interconnected in pairs by respective rigid ties.

11. An enclosure according to any one of the preceding claims, in which the cover sheet is of clear plastics sheeting.

1 2. An enclosure having a cover sheet which is maintained in tension by a number of flexurally stressed or spring-loaded arched supports which are braced against the inside surface of the cover sheet, each support having at least one free end which is braced against a lower portion of the cover sheet so as to maintain the latter in tension.

1 3. An enclosure according to Claim 12, in which the arched supports have free lower ends and are anchored at their upper ends to a fixed support, thereby forming a lean-to enclosure.

14. A portable enclosure substantially as herein described with reference to and as shown in the accompanying drawings.