GB2270935A

GB2270935A - Stressing mechanism for tent roof.

Info

Publication number: GB2270935A
Application number: GB9220233A
Authority: GB
Inventors: Laurence Joseph Bennett
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-09-24
Filing date: 1992-09-24
Publication date: 1994-03-30
Also published as: GB9220233D0

Abstract

A stressing mechanism is provided for a tent which comprises at least two elongate members (1) each pivotally connected at one end (5) to different fixed points of a tent and at the other end to each other at a coupling point (3). Struts (2) are each pivotally mounted at one end to a respective elongate member(1), and at the other end to each other at a second coupling point(4). By forcing the second coupling point towards the first coupling point, the elongate members are induced to flex until a point of maximum flexure in the members (1) and maximum compression in the struts (2) is reached. Further motion of the second coupling point is accompanied by reduced flexure and compression. The coupling points are held together by a locking force resulting from the reduction in flexure and compression forces. <IMAGE>

Description

TENSIONING MECHANISM This invention relates to a tensioning mechanism for a tent.

A tent consists of a number of sheets of canvas or other fabric, generally sewn together into an integral structure, and mounted on a framework. This framework holds the fabric under tension.

The framework for a tent is often complex.

Vertical members generally need to be held upright by ropes and ground pegs, or struts between members, or both.

Tent assembly is thus difficult and time consuming, and typically necessitates a large number of components. For certain types of structure it is also difficult to provide satisfactory framework. For example, large marquees, especially those with a circular floor area, require large poles within the marquee to hold up the roof. Assembly of such marquees is not only difficult, requiring skilled contractors, but the presence of such central poles may be considered unsightly and render the marquee unsatisfactory for its desired purpose.

It would therefore be desirable for apparatus to be developed which would enable tents to be assembled without the occurrence of these problems found in the prior art. In particular, it is desired that the number of components be minimised, that assembly be possible both simply and effectively, and that central poles not be required for tents and marquees. It is these problems of the prior art that are addressed by the invention.

Accordingly, the invention provides a tensioning mechanism for a tent, comprising: at least two elongate members, each elongate member being capable of flexure and the elongate members being pivotally connected together at one end at a first coupling point, the other ends of the elongate members being pivotally connected in use to different fixed points of the tent; at least two struts, each strut being pivotally connected at one end to an intermediate point along a respective elongate member, the other ends of the struts being pivotally connected at a second coupling point;; wherein in use the second coupling point is movable from a position remote from the first coupling point, through a position where compression force in the struts and the flexure of the elongate members are at a maximum, to a position where the first and second coupling points are adjacent and where the compression force and flexure are below their maximum values.

In another aspect, the invention provides a method for tensioning a tent, comprising the steps of pivotally connecting each of at least two elongate members at one end thereof to different fixed points of the tent, the other ends of each elongate member being pivotally connected together at a first coupling point whereby at least two struts are each pivotally connected at one end thereof to an intermediate point along a respective elongate member, the other ends of the struts being pivotally connected at a second coupling point; disposing a tent fabric over the rod members and the first coupling point; exerting force on the second coupling point to urge the second coupling point towards the first coupling point, such that a compression force in the struts and a flexure in the elongate members reaches a maximum value;; and further motion of the second coupling point until it abuts the first coupling point, whereby the compression force in the struts and the flexure in the elongate members fall substantially below their maximum values.

A specific embodiment of the invention is described below, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows an embodiment of the invention in an untensioned position.

Figure 2 shows the embodiment of Figure 1 in a tensioned position.

Figure 3 illustrates the flexure of a rod member in an embodiment of the invention on movement between an untensioned and a tensioned position.

Figure 4 shows the embodiment of Figure 1 folded for storage.

Figure 1 shows an embodiment of the invention with two elongate members 1. This is the minimum number of elements which is required for the mechanism. Obviously, a greater number of such elements can be used; the only important criterion is that forces balance within the framework structure. This embodiment uses as elongate members flexible rods 1; however, different embodiments could employ flexible plates or bars. The essential limitation on the support is that flexibility transverse to its length is possible.

The flexible rods 1 are connected at ends 5 to fixed points of the tent structure. For example, these points could be situated at the top of the side walls of a tent. The other ends of the flexible rod meet at a top coupling 3. Where the structure is to form part or whole of a tent roof, the tent material is placed over the surface formed by the flexible rods. It is not generally necessary for tent material to be fixed to this surface but fixings may be desirable, especially at fixed points 5 of the tent structure.

At points 6 along the flexible rods there is a hinged connection to a strut 2. These struts 2 join the flexible rods 2 to a bottom coupling 4. The struts 2 should not show comparable flexure to the flexible rods, but they should be adapted to withstand compressional forces along their length.

The operation of the device will be described with reference to Figures 1, 2 and 3. From the untensioned position shown in Figure 1 upward force is exerted on bottom coupling 4, causing it to move upwards. This sets up a compression force in each of the struts 2. This compression force is balanced by flexure of the flexible rods 1. As bottom coupling 4 is moved upwards, both the compression force in the struts 2 and the strain of the flexure of rods 1 increases until, at any rate in this embodiment, the struts 2 are essentially coplanar. At this point the compression force in the struts is at its greatest value and the flexure of the flexible rods 1 is also at its greatest. In figure 3 the initial position is designated X, and this position of greatest strain in the flexible rods is designed Y.

However, further upward force exerted on bottom coupling 4 elevates it still further. This both reduces the compression force in struts 2 and reduces the flexure of rods 1. Once the bottom coupling is moved past the position of maximum compression and flexure, it will move towards the top coupling without the need for further force to be exerted. Further upward motion of bottom coupling 4 will be stopped by abutment of the couplings 3 and 4, resulting in the end position of Figure 2, designated Z in Figure 3.

The nature of the device is such as to impose certain geometrical constraints on the length of the struts 2. These must have a length greater than the horizontal distance between points 6 and the coupling axis, and also greater than the minimum necessary to maintain flexure in rods 1 when the couplings abut, or else the lower coupling will not reach this abutment position. The strut length should not be so great as to cause excessive flexure in rod 1 at the position of maximum flexure.

The apparatus is now locked in this position, as a significant downward force must be exerted on the bottom coupling 4 for it to reach the position of greatest compression and flexure. However, it may be desirable for safety reasons to introduce an additional locking between the top and bottom couplings to prevent any possibility that freak forces on the bottom coupling will move it below the position of maximum compression.

When the apparatus is relaxed and removed from the fixed points 5 of the tent assembly, it can be easily contracted further for storage. The storage position is shown in Figure 4. The apparatus is contracted to a position where the flexible rods 1 and struts 2 are parallel, minimising the volume of storage space required.

The same principle can be employed if there are a multiplicity of rods and struts, other than two of each as illustrated here. For ease of assembly and disassembly, it is preferred that the tent fabric should remain on the apparatus throughout disassembly, storage and subsequent assembly.

By application of the principle described above an apparatus with three or more rods and struts can be used to support the entire roof of a tent assembly with no need for a central pole in the tent. Composite arrangements of a plurality of such devices can be used in more complex tent structures. Alternatively, a row of two-rod devices can be used in rectangular tents. In circular tents, there can be a number of radial rods and struts, in the manner of an umbrella. Similarly, in square tents with a pyramidal roof, rods and struts can radiate out from the centre point to the corners and perhaps the edges of the roof base.

Moreover, each individual apparatus unit of two couplings and associated rods and struts can be stored compactly as a unit, aiding greatly storage and assembly of tents and marquees.

Claims

CLAIMS:

1. Tensioning mechanism for a tent, comprising: at least two elongate members, each elongate member being capable of flexure and the elongate members being pivotally connected together at one end at a first coupling point, the other ends of the elongate members being pivotally connected in use to different fixed points of the tent; at least two struts, each strut being pivotally connected at one end to an intermediate point along a respective elongate member, the other ends of the struts being pivotally connected at a second coupling point;; wherein in use the second coupling point is movable from a position remote from the first coupling point, through a position where compression force in the struts and the flexure of the elongate members are at a maximum, to a position where the first and second coupling points are adjacent and where the compression force and flexure are below their maximum values.

2. Tensioning mechanism as claimed in claim 1, wherein the tensioning mechanism comprises at least three elongate members extending radially about an axis defined by the coupling points.

3. Tensioning mechanism as claimed in claim 1 or claim 2, further comprising a locking means for engaging the first and second coupling points.

4. Tensioning mechanism as claimed in any preceding claim, further comprising means for attaching a tent fabric to one or more of the elongate members and the first coupling point.

5. Tensioning mechanism as claimed in claim 4, where the means for attaching the tent fabric are located at the connection between the elongate members and the fixed points of the tent assembly.

6. Method for tensioning a tent, comprising the steps of pivotally connecting each of at least two elongate members at one end thereof to different fixed points of the tent, the other ends of each elongate member being pivotally connected together at a first coupling point whereby at least two struts are each pivotally connected at one end thereof to an intermediate point along a respective elongate member, the other ends of the struts being pivotally connected at a second coupling point; disposing a tent fabric over the rod members and the first coupling point; exerting force on the second coupling point to urge the second coupling point towards the first coupling point, such that a compression force in the struts and a flexure in the elongate members reaches a maximum value; ; and further motion of the second coupling point until it abuts the first coupling point, whereby the compression force in the struts and the flexure in the elongate members fall substantially below their maximum values.

7. A tensioning mechanism for a tent as herein described with reference to the accompanying drawings.

8. A method of tensioning a tent as herein described with reference to the accompanying drawings.