NO20181278A1 - A tent system for protecting a workplace. - Google Patents

Description

BACKGROUND

[0001] The present invention concerns a tent system for protecting a workplace.

[0002] There is a need to protect workers and workplaces from wind, rain, snow, sun etc. Traditionally, this has been achieved with tents and/or tarpaulins, which are heavy and require substantial time and effort to put in place.

[0003] The objective of the present invention is solve or alleviate at least one of the problems above while retaining benefits from prior art.

SUMMARY OF THE INVENTION

[0004] This is achieved by a tent system according to claim 1. Further embodiments and features appear in the dependent claims. In the claims, we generally adhere to the convention that articles ‘a’, ‘an’, ‘the’ mean ‘(the) at least one’, whereas ‘one’, ‘two’ etc. mean exactly one, two etc. Further, ‘for’ should be construed ‘suitable for’.

[0005] More particularly, the invention concerns a tent system for protecting a workplace. The tent system comprises a tent canvas and is distinguished by at least two coaxial, approximately semi-circular, carrier arches, wherein each carrier arch comprises N > 1 inflatable straight cylindrical elements arranged end-to-end.

[0006] The approximately semi-circular shape of the carrier arches creates an outer surface greater than an inner surface exposed to an overpressure above atmospheric pressure. This creates a lifting force that depends on the radial dimensions of the carrier arches such that larger radial dimensions compensate for smaller overpressures. In practice, an inexpensive fan can lift a large structure.

[0007] The tent system preferably further comprises at least one inflatable stiffener extending perpendicular to and attached to the carrier arches. A main purpose is to keep the carrier arches at a fixed distance from each other. An inflatable stiffener, as opposed to a rigid strut, can be folded together with the rest of the tent and need no extra mounting when the arches are raised.

[0008] The tent system preferably further comprises rails for moving the carrier arches to and at the workplace. During assembly, rails enable one person to inflate and move tent modules to the workplace in a fast and efficient manner. Later, rails facilitate moving the tent/arches to wherever a protective tent is needed or desired.

[0009] Preferably, the tent canvas has attached pockets for inserting inflatable elements. This facilitates replacements compared to sewing, welding, gluing etc., and thereby facilitates maintenance and repairs.

[0010] Preferably, the system has safety relief valve mounted on the carrier arches and/or the inflatable stiffener. The safety relief values prevent damage due to excessive overpressure.

[0011] In some embodiments, the inflatable straight cylindrical elements have tapered ends, each with an angle 180°/N to the longitudinal axis of the straight cylinder. Among these, embodiments with N = 6 straight cylinders are found to be a good compromise between approximating a semi-circle and avoiding superfluous (sewn, welded, glued etc.) seams.

[0012] In alternative embodiments, the inflatable straight cylindrical elements have rounded ends. If one such element bursts, no other element is affected.

[0013] The inflatable straight cylindrical elements may have an elliptical cross section. In larger tents, this may save fabric without sacrificing lifting power.

[0014] The inflatable stiffener(s) may be designed for a different pressure than the carrier arches. Since the size of the carrier arches may compensate for a low pressure, a higher pressure may be desirable for the inflatable stiffeners.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The invention will be described in greater detail below be means of an exemplary embodiment with reference to the accompanying drawings, in which:

Fig. 1 is a front view of a preferred embodiment,

Fig. 2 is a top view of the embodiment in Fig. 1,

Fig. 3 shows an end wall,

Fig. 4 illustrates a pump circuit for filling inflatable elements,

Fig. 5 illustrates use of the invention,

Fig. 6 shows an inflatable cylindrical element,

Fig. 7 shows an elliptical cross-section of an inflatable element, and

Fig. 8 illustrates rails for moving a tent.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0016] The drawings are schematic and not to scale. Several details known to the skilled person are omitted from the drawings for clarity of illustration.

[0017] Figs. 1 and 2 illustrate a tent system 100 for protecting a workplace 10. Main parts include a tent canvas 110, at least two inflatable carrier arches 120, one of which is visible in Fig. 1, and at least one inflatable stiffener 130 extending perpendicular to the arches 120.

[0018] The carrier arches 120 are mounted on a pair of rails 140 attached to a ground 1 at the workplace 10. The rails 140 keep the lower ends of the carrier arches 120 together, and at the same time leave the ground 1 free from struts, ribbons etc. Without lateral support, inflated elements 120 would form flat horizontal structures rather than carrier arches. The bottom of the arches 120 may be attached to the ground 1 by any known means, so rails 140 are not strictly required.

[0019] However, the rails 140 make it possible to move the tent in a convenient manner, e.g. as work progress and moves a workplace 10 along a road. Since inflated carrier arches 120 are quite flexible, the rails 140 just have to be reasonably aligned.

[0020] Fig. 1 shows a preferred embodiment of the system 100 viewed from a front during operation. Each carrier arch 120 essentially follows a semicircle with radius R and comprises identical straight cylinders 121 with tapered end faces. The radius R is typically about 1.5 m or greater, for example 3, 10 or 15 m.

[0021] The semi-circular shape distributes loads evenly over the construction. Moreover, it facilitates a construction that lift itself when inflated at low pressure, e.g. about 0.2 bar above atmospheric pressure. This is illustrated by the following example:

Example 1: Lifting force

[0022] Assume that the arch 120 is approximately semi-circular with outer radius (R d) and inner radius R. A pressure p acts equally on an outer and an inner surface, such that the net lifting force F ≈ c1p[π(R+d) - πR] = c1π·pd, where c1is a proportionality constant. In words, the lifting force is approximately proportional to the diameter d of the cylinders 121, and does not depend on the radius R of the arch. Moreover, a larger diameter d compensates for a lower pressure p, e.g. in the range 0.1 - 0.3 bar provided by inexpensive fans. Since the lifting force does not depend on radius R, the same lightweight fabric may be used in inflatable elements for tents with radius R = 1.5 or 15 m – the fabric just needs to contain a pressure about 0.2 bar.

[0023] Identical cylinders 121 enable larger series, thereby reducing manufacturing costs. Straight cylinders 121 further facilitate production because one relatively simple apparatus can sew, weld or glue straight longitudinal seams along inflatable cylinders 121 of different lengths and different diameters d. Conversely, an adjustable apparatus would be required for seams with different radius R.

[0024] Fig. 1 shows 6 straight cylinders 121 per arch 120, so each end tapers 180°/6 = 30° to the cylinder axis. In a carrier arch 120 with N straight cylinders 121, each taper would be 180°/N. We have found that N = 6 is a good compromise between approximation to the semicircle and number of elements for most sizes of interest. For example, decreasing N to 2 yields a triangular shape, which does not withstand vertical forces nearly as well as the embodiment in Fig. 1. Thus, a higher overpressure would be needed to carry the weight of the tent canvas 110 and a possible snow load. Opposite, increasing N to 10 increases the number of seams without a corresponding increase in load capacity.

[0025] Fig. 2 is a top view of the embodiment in Fig. 1, more precisely a tent module 101 with a connection piece 111 in both ends. The connection piece 111 is a reinforced part of the tent canvas 110 with suitable connection means depending on size. For example, a zipper may be adequate for smaller tents, whereas eyelets and a line may be more appropriate for larger tents. The inflatable carrier arches 120 and stiffener(s) 130 are preferably inserted in pockets 112 attached to the tent canvas 110. This facilitates maintenance and repairs.

[0026] Fig. 3 illustrates an end wall 102 with an opening 103. The radius R equals the radius R in Fig. 1. The connection piece 111 fits the connection piece 111 in Fig. 2.

[0027] Fig. 4 is a schematic view of a filling device 400, in which an inlet line 410 leads to a branch 420 for the carrier arches 120 and a branch 430 for the stiffener(s) 130.

[0028] The inlet line 410 comprises a fan 411, a manually operated valve 412 and a safety relief valve 413. Here and in the following, a safety relief valve is any device designed to open at a predetermined pressure to avoid damage on the inflatable elements 120, 121, 130.

[0029] Optional butterfly valves 421 on line 420 and 431 on line 430 illustrate that the pressures on lines 420 and 430 may be different, at least in principle.

[0030] Check valves 422 and 432 can be mounted on pipes or tubes leading to the inflatable elements 120, 130. However, the inflatable elements 120, 130 must have some form of built in check valve to prevent air from escaping when they are inflated. Hence, check valves 422 and 432 on tubes or pipes leading to the inflatable elements 120, 130 are optional.

[0031] Each carrier arch 120 preferably has at least one safety relief valve 125 that opens if the internal pressure exceeds a predetermined value. Each stiffener element 130 preferably has a safety relief valve 135 for the same purpose. Since the inflatable elements 120 and 130 may contain different pressures, the safety relief valves 125 and 135 may have different design or sizes.

[0032] Outlet valves on the inflatable elements 120, 121, 130 are not shown for clarity of illustration. However, real embodiments have outlet valves for deflating the tent after use. Suitable valves of all types just described are commercially available, and need no detailed explanation herein.

[0033] Fig. 5 illustrates assembly and use of the proposed tent system. First, rails 140 are attached to the ground at the workplace 10. Next, a module 101 is inflated, equipped with an end wall 102 and pushed to the workplace 10. A second module is inflated, pushed into place and joined to the first module by means of the connection piece 111. The procedure is repeated until the tent has a desired length. In Fig. 5, the third module has an end wall 102 illustrating the end of a tent.

[0034] Reference numerals 410 – 430 are explained with reference to Fig. 4. Fig. 5 shows the lines 420 and 430 as combinations of tubes and pipes. As illustrated in example 1, the carrier arches 120 raise the module 101 when inflated. Thus, one person can assemble a large tent from modules 101 in a fast and convenient manner. Later, the entire assembled tent may move along the rails 140 as needed or desired.

[0035] Fig. 6 shows an alternative embodiment of the cylinder 121. This embodiment has rounded ends instead of the tapered ends in Fig. 1, and an inlet 122 with the same function as check valve 422 in Fig. 4. The safety relief valve 125 corresponds to the valve 125 in Fig. 4.

[0036] The rounded ends permit many angles through the carrier arch 120. Further, each such cylinder 121 is a self-contained unit such that one burst cylinder 121 does not affect other cylinders 121 in the arch 120. It is understood that self-contained cylinders 121 as shown in Fig. 6 must be contained in channels or extensive pockets (112 in Fig. 2).

[0037] Fig. 7 is a cross section through the tent canvas 110 and pocket 112 in Fig. 2. In the present example, the cross section through the cylinder 121 is elliptical rather than circular. The major axis of the ellipse has length d and equals d in Fig. 1 and example 1. The elliptical cross section has a smaller circumference than a circle, which may save fabric. However, a distance piece 123 such as a ribbon must be attached along the minor axis of the ellipse, e.g. by sewing, welding or gluing as known in the art. Without the distance piece 123, the cross section would be circular due to pressure acting equally in all directions. Accordingly, the embodiment shown in Fig. 7 only saves fabric in elements 121 where the savings in circumference exceed the cost for the element 123 with associated (welded or glued) seams.

[0038] Regardless of which embodiments are selected for the various parts, the proposed system is modular, and should have as many reusable modules and components as possible, e.g. identical cylinders 121 as shown in Fig. 1 or Fig. 7 and standardised rail segments.

[0039] Fig. 8 illustrates rails 140 for moving a tent at the workplace, not necessarily along straight rails 140. Specifically, Fig.8 resembles a traditional railway junction with a curved segment. The proposed rails may include similar junctions and other known equipment. However, moving the equipment for inflating the tent is usually more convenient than building an extensive rail system, so in real embodiments, we expect the rails 140 to be relatively short, for example up to a few times the length of a tent. Short and light rail segments may be combined to rails 140 of any desired length and shape.

[0040] The proposed tent has many potential applications. We finish with two examples:

Example 2: Workplace in a ditch along a road

[0041] For this, a small tent with R in the range 1.0 – 1.5 m might be appropriate. The rails 140 are convenient means to even out the ground, and may be made of aluminium tubing. As work progresses along the ditch, rails can be moved from behind the tent to the front of the tent. Some rail segments can be curved. Regardless of the shape of the rails, a light tent and light rail segments enable one person to move the tent with little effort.

Example 3: Temporary assembly hall

[0042] Assume that a company sometimes needs to assemble a construction that is larger than its workshop, and that the company has access to a parking lot outside the workshop. One or a few person may assemble temporary rails 140 along the parking lot and inflate a tent, for example with R in the range 5 - 15 m, whenever needed. At other times, the tent and rails are stored safely and the ground is used for parking. This is less expensive than enlarging the workshop. Further, maintaining a large tent is less expensive than maintaining a large building because cleaning, repairs and replacements can be done at ground level.

[0043] While the present invention has been illustrated by examples and schematic drawings, the scope of the present invention is set forth in the accompanying claims.

Claims (10)

Claims

1. A tent system (100) for protecting a workplace (10), wherein the system (100) comprises a tent canvas (110) and is characterised by at least two coaxial, approximately semi-circular, carrier arches (120), wherein each carrier arch (120) comprises N > 1 inflatable straight cylindrical elements (121) arranged end-to-end.

2. The system according to claim 1, further comprising at least one inflatable stiffener (130) extending perpendicular to and attached to the carrier arches (120).

3. The system according to claim 1 or 2, further comprising rails (140) for moving the carrier arches (120) to and at the workplace (10).

4. The system according to any preceding claim, wherein the tent canvas (110) has attached pockets (112) for inserting inflatable elements (120, 130).

5. The system according to any preceding claim, further comprising a safety relief valve (125, 135) mounted on the carrier arches (120) and/or the inflatable stiffener (130).

6. The system according to any preceding claim, wherein the inflatable straight cylindrical elements (121) have tapered ends, each with an angle 180°/N to the longitudinal axis of the straight cylinder.

7. The system according to claim 6, wherein N = 6.

8. The system according to any claim 1-5, wherein the inflatable straight cylindrical elements (121) have rounded ends.

9. The system according to any preceding claim, wherein the inflatable straight cylindrical elements (121) have an elliptical cross section.

10. The system according to any claim 2-9, wherein the inflatable stiffener(s) (130) is/are designed for a different pressure than the carrier arches (120).