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(11) | EP 1 286 002 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Shutters |
| (57) There is disclosed a cornering shutter for a structural element having a first channel
(40) and a second channel (42) contiguous therewith and substantially perpendicular
thereto, the shutter comprising a folded, one piece arrangement of sheet material. |
[0002] The present inventor's earlier publication EP 0 866 196 discloses an extremely convenient form of shuttering for use in the construction industry in which a fluted plastic material is folded to provide a sacrificial shutter.
[0003] Although the shutters of EP 0 866 196 is advantageous, it is a relatively time consuming and labour intensive process to provide an arrangement which can accommodate structural comer elements, such as a foundation for a building in the region where two walls meet at 90°. In fact, this is a general problem with shuttering used in the construction industry, since, two shutters must be suitably positioned at right angles to each other, and this arrangement must be retained in place during construction of the structural feature.
[0005] According to a first aspect of the invention there is provided a cornering shutter for a structural element having a first channel and a second channel contiguous therewith and substantially perpendicular thereto, the shutter comprising a folded, one piece arrangement of sheet material .
[0006] The shutter overcomes the above described problems, being easily and quickly assembled, into the correct, right angled, configuration by a simple cutting and folding procedure. Furthermore, before assembly, the shutter can be flat packed, for ease of transportation and storage. The shutter enables the continuation of a channel pathway through 90° (the channel pathway comprising the first and second channels), with the dimensions of the channel pathway being unchanged.
[0007] Each channel may be three sided, comprising a base portion and two wall portions. Such a configuration is suitable for shuttering ground beams.
[0009] The shutter may comprise fluted or corrugated material. Such arrangements exhibit favourable mechanical properties. The sheet material may comprise two other wall sections spaced apart by a plurality of internal wall sections to form an internally fluted structure. An advantage with this material is that it is convenient to secure the shutter in place by locating clips in the flutes. Additionally, the structure is extremely strong. The sheet material may be plastic, which may be polypropylene or a modified polypropylene.
[0010] The shutter may further comprise one or more reinforcement cages disposed in at least one of the channels.
[0011] According to the second aspect of the invention there is provided a cornering structural element comprising a set construction material and at least one shutter according to the first aspect of the invention.
[0014] According to a third aspect of the invention there is provided a method of making a cornering structural element comprising the steps of:
folding a sheet material to provide a one piece cornering shutter having a first channel and a second channel contiguous therewith and substantially perpendicular thereto;
pouring a settable construction material into said cornering shutter; and
allowing said settable construction material to set.
[0015] The method may comprise the steps of:
providing a first fold line in the sheet material;
cutting the sheet material along a first cut line which extends from a first edge of the sheet material, the first cut line extending substantially perpendicularly to the first fold line and intersecting the first fold line;
providing a second fold line which is co axial with the first cut line;
folding the sheet material along the first fold line to provide an outer wall; and
folding the sheet material along the second fold line thereby causing a portion of the sheet material to rotate through substantially 90°.
[0016] It will be appreciated that the ordering of many of these steps, and many of the steps detailed below, are interchangeable. Furthermore, it will be appreciated that the term "intersect", as used herein, includes instances in which the a cut line meets a fold line but does not extend across the fold line. Indeed, such instances represent the preferred embodiment.
[0017] The method may comprise the step of folding the sheet material along a third fold line to provide an inner wall.
[0018] The method may comprise the steps of:
cutting a portion of the third fold line;
providing a fourth fold line extending from the first edge substantially perpendicularly to the third fold line and intersecting the cut portion of the third fold line; and
folding the sheet material along the fourth fold line to provide at least a portion of the inner wall.
[0019] The method may comprise the steps of:
cutting the sheet material along a second cut line extending from the first edge substantially perpendicularly to the third fold line, the second cut line intersecting the third fold line to define a panel portion; and
folding the panel portion along the third fold line to provide at least a portion of the inner wall.
[0020] The method may further comprise the steps of:
positioning the shutter in a trench; and
backfilling the trench so as to support the shutter.
[0025] The shutter may remain in contact with the set construction material as a sacrificial shutter.
[0027] Embodiments of shutters in accordance with the invention will now be described with reference to the accompanying drawings, in which:-
- Figure 1
- is a plan view of a precursor to the cornering shutter;
- Figure 2
- is an elevated side view of an intermediate stage in the production of a cornering shutter;
- Figure 3
- is an elevated side view of a cornering shutter;
- Figure 4
- is a cross sectional view of internally fluted sheet material; and
- Figure 5
- shows a panel and a panel portion secured by a clip.
[0028] Figure 1 shows a plan view of a precursor 10 of a cornering shutter according to the invention. The precursor 10 comprises a sheet material which has been prepared by forming fold lines and cut lines therein.
[0029] The precursor 10 comprises a first fold line 12 in the sheet material which extends from one edge of 14 the sheet material to an opposing edge 16 thereof, and a first cut line 18 which extends from a further edge 20 of the sheet material, the first cut line 18 extending substantially perpendicularly to the first fold line 12 and meeting the first fold line 12 at the point 22. The precursor 10 also comprises a second fold line 24 which is coaxial with the first cut line 18.
[0030] The precursor 10 further comprises a third fold line 26 which extends from the edge 14 to the edge 16, and which is substantially parallel to the first fold line 12. A portion 26a of the third fold line 26 is cut, and a fourth fold line 28 extends from the edge 20, substantially perpendicularly to the third fold line 26, this fourth fold line 28 meeting one end of the cut portion 26a of the third fold line 26. The precursor 10 is cut along a second cut line 30 extending from the edge 20 substantially perpendicularly to the third fold line 26, the second cut line 30 meeting the third fold line to define a panel portion 32.
[0031] The precursor 10 is then manipulated in the manner described below to provide a cornering shutter having a first channel and a second channel contiguous therewith and substantially perpendicularly thereto. Each channel comprises a three sided arrangement having a base portion of width A and two wall portions of height B.
[0032] Folding of the sheet material precursor 10 is performed as detailed below to produce an intermediate structure 33 which is shown in Figure 2.
[0033] The precursor 10 is folded along the first fold line 12 to provide an upstanding outer wall 34. The outer wall 34 comprises two sections 34a, 34b on either side of the second fold line 24. The sheet material is then folded along the fourth fold line 28 to provide an upstanding panel 36, the panel being foldable in this way due to the first cut line 18 and the cut portion 26. The panel portion 32 is folded so that the panel portion 32 is upstanding from the unfolded body of the precursor 10. In this way the intermediate structure 33 is produced.
[0034] Next, the intermediate structure 33 is rotated by folding along the second fold line 24 so that the section 34b of the outer wall 34 is substantially perpendicular to the section 34a. The rotation also causes the panel 36 to come into contact with the panel portion 32, thereby producing the cornering shutter 38 shown in Figure 3. The cornering shutter 38 possesses a first 40 channel and a second channel 42 contiguous therewith and substantially perpendicular therewith. It is highly advantageously that this alignment of the two channels 40, 42 follows directly and "automatically" from the folding process, and requires no careful alignment procedure. If necessary, the shutter 38 can be secured: this may be achieved by securing the panel 36 and the panel portion 32 together.
[0035] A further advantage of the arrangement of Figure 3 is that the panel 36 and panel portion 32 (which form part of an inner wall of the shutter 38) are easily returned to an unfolded state (whilst the remainder of the sheet material is retained in a cornering, right angled configuration). This is highly advantageous if access to the interior of the cornering shutter is required, for example for steel fixing.
[0036] Figure 4 shows a cross sectional view of a preferred embodiment of sheet material which comprises two outer wall sections 50, 52 spaced apart by a plurality of internal wall sections 54 to form an internally fluted structure having internal flutes 56.
[0037] The flutes can, however, comprise grooves formed in the surface of the section. In a related configuration, the section can be corrugated. Extruded polypropylene is a highly suitable material. The precise dimensions and densities used can, of course, be varied so as to provide shutters suitable for the task envisaged. However, it has been found that sections having thickness/weight characteristics (t/w) in range 4.0/700 to 9.0/2000 are well suited to a wide range of applications. The thickness is the dimension 't' shown in Figure 4, in millimetres, and the weight 'w' is the weight in grams per square metre.
[0038] The extruded section may be creased, or fold lines may be formed by any suitable means, even on site. Such means might comprise a platen equipped with suitably positioned and adapted blades. An advantage of such an approach is that the shutter can be flat packed for transportation and storage, and folded into shape along the crease lines on site.
[0039] It is preferred that the internal flutes 56 extend transversely across each channel. An advantage with such an arrangement is that it is very convenient to secure the shutter in place by locating clips in the flutes. Figure 5 shows the panel 36 and panel portion 32 in contact after formation of the shutter. As can be seen, a generally U shaped clip 60 having two tubular members 62, 64 can be disposed in a flute of the panel 36 and a flute of the panel portion 32. The clip can be manufactured from metal or any other suitable material, such as plastic.
[0040] Structural elements may be formed by filling the cornering shutter with a settable material such as concrete. One or more reinforcement cages can be positioned in the shutter. The manner in which these operations are performed can be substantially as described in EP 0 866 196.
[0041] Other arrangements may be contemplated by the skilled person who, once armed with the present disclosure, might usefully refer to texts on paper folding techniques, such as origami. For example, it is possible to modify the precursor 10 shown in Figure 1 by extending the first cut line 18 so that it runs into the portion of Figure 1 occupied by the second fold line 24, or by cutting out altogether the panel portion 32 or panel 36.
folding a sheet material to provide a one piece cornering shutter having a first channel and a second channel contiguous therewith and substantially perpendicular thereto;
pouring a settable construction material into said cornering shutter; and
allowing said settable construction material to set.
providing a first fold line in the sheet material;
cutting the sheet material along a first cut line which extends from a first edge of the sheet material, the first cut line extending substantially perpendicularly to the first fold line and intersecting the first fold line;
providing a second fold line which is coaxial with the first cut line;
folding the sheet material along the first fold line to provide an outer wall; and
folding the sheet material along the second fold line thereby causing a portion of the sheet material to rotate through substantially 90°.
cutting a portion of the third fold line;
providing a fourth fold line extending from the first edge substantially perpendicularly to the third fold line and intersecting the cut portion of the third fold line; and
folding the sheet material along the fourth fold line to provide at least a portion of the inner wall.
cutting the sheet material along a second cut line extending from the first edge substantially perpendicularly to the third fold line, the second cut line intersecting the third fold line to define a panel portion; and
folding the panel portion along the third fold line to provide at least a portion of the inner wall.
positioning the shutter in a trench; and
backfilling the trench so as to support the shutter.