GB2607683A

GB2607683A - Method of forming twisted building façade element and apparatus

Info

Publication number: GB2607683A
Application number: GB2204763.3A
Authority: GB
Inventors: Trevor Mcgrath Alan
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-02-12
Filing date: 2021-02-12
Publication date: 2022-12-14
Anticipated expiration: 2041-02-12
Also published as: GB2607683B; GB202204763D0

Abstract

A method, and apparatus 10, is for forming a twisted building façade element, such as a louvre 12, from an elongate building façade element precursor comprising metal. The apparatus includes a first clamp 14 for releasably clamping a first clampable portion 16 of the precursor and a second clamp 18 for releasably clamping a second clampable portion 20 of the precursor. The second clamp is spaced apart from, and linearly aligned with, the first clamp. At least one intermediate clamp (170, Figure 10) between the first and second clamps is for clamping an intermediate clampable portion of the precursor. The intermediate clampable portion is between the first and second clampable portions. A linear displacement means (38, Figure 3) is for linearly displacing the first clamp relative to the second clamp so as to tension the building-façade-element precursor when clamped by the first and second clamps. A rotation means (50, Figure 4) is for rotating the second clamp relative to the first clamp so as to twist the precursor when clamped by the first and second clamps and tensioned. There may be first and second intermediate clamps, each for clamping a separate intermediate portion.

Description

Method of Forming Twisted Building Façade Element and Apparatus The present invention relates to a method of forming a twisted building facade element, in particular a building louvre. The invention further relates to an apparatus for forming a twisted building facade element, in particular a building louvre.

Building louvres are typically installed on buildings as part of a building facade to block rain and/or excessive direct sunlight to the building whilst permitting the passage of air for ventilation and/or permitting indirect light. Louvres may also be installed for aesthetic purposes. Building louvres are conventionally installed as spaced apart planar slats and may be at an angle to the vertical direction.

However, a louvre or building facade element with a helical shape may be desirable for decorative purposes.

To form a helical shape, it may be possible to mould, cast or press the material into the helical shape. However, this may be expensive or result in a building facade element with poor mechanical properties, due to the difficulties in moulding such a complex 15 shape.

Alternatively, a piece of deformable material may be twisted into the helical shape.

Relatively pliable materials such as plastics or plastic composites materials may be relatively convenient to twist. However, plastics and plastic composites are typically combustible and building regulations usually require for building facade elements to be 20 formed from non-combustible or substantially non-combustible materials.

Under typical service conditions, conventional engineering metals such as aluminium alloys, steel, or titanium alloys are non-combustible. However, it has been found that such materials are difficult to twist and/or to twist to form a uniformly twisted shape or a uniform helix.

The present invention seeks to provide a solution to these problems.

According to a first aspect of the present invention, there is provided a method of forming a twisted building facade element, the method comprising a): providing an elongate building-facade-element precursor, the building-facade-element precursor comprising metal and having a first clampable portion and a second clampable portion, the first and second clampable portions spaced apart from each other in a longitudinal direction of the building-façade-element precursor; b) clamping the building-façade-element precursor at the first clampable portion with a first clamp and clamping the buildingfaçade-element precursor at the second clampable portion with a second clamp; c) imparting tension to the building-facade-element precursor via the first and second clamps; d) rotating the second clamp relative to the first clamp so as to twist the buildingfaçade-element precursor whilst the building-facade-element precursor is under said tension to form the twisted building façade element; and e) releasing the twisted building façade element from the first and second clamps.

A building façade element which comprises metal is typically less combustible than plastics, for example. Metal is usually deformable and so the precursor can be twisted into a helical or twisted shape. The clamps allow for the precursor to be held, and the relative rotation of the clamps causes twisting of the precursor. By applying tension to the precursor, rippling, crumpling, crimping or other unwanted deformation at the outward edge of the precursor can be prevented. This allows for a building façade element with a smooth and uniform twist or helical shape to be created.

Preferably, the building façade element may be a building louvre.

Advantageously, the second clamp may be rotated relative to the first clamp by at least 90 degrees.

Beneficially, the second clamp may be rotated relative to the first clamp by at least 180 degrees.

Additionally, the method may further comprise the step f) before step d) comprising determining a desired extent of twist of the building façade element, and wherein during step d) the second clamp is rotated relative to the first clamp to twist the building-façade-element precursor by more than said desired extent of twist so that when the first clamp and the second clamp are relaxed relative to each other the building-façade-element precursor partly rebounds to form the twisted building façade element having the desired extent of twist. Due to the resilience or elasticity of metal, the precursor typically partially rebounds or untwists from the degree of twist provided by the clamps. As such, the precursor should be over-twisted so that such rebounding is taken into account.

Preferably, the desired extent of twist may be a twist of 180 degrees or substantially 180 degrees and the building-facade-element precursor is twisted by 200 degrees or substantially 200 degrees.

Beneficially, the building-façade-element precursor may consist of metal or consist essentially of metal. By consisting or consisting essentially of metal, the risk of combustion of the building façade element is further reduced.

Advantageously, the metal may consist or consist essentially of aluminium or an alloy thereof Aluminium is lightweight, so provides a limited load on the building as compared to other metals, such as steel, and is considered non-combustible in the building industry. Aluminium also typically has a lower shear modulus than steel or titanium, so could be a more convenient material to twist.

Optionally, the metal may comprise aluminium and may have been heat treated 10 according to a T4 or T6 aluminium heat treating temper code.

Preferably, the building-façade-element precursor may be planar or substantially planar. A planar, sheet-like or thin precursor is easier to twist and forms a more suitable helical shape Advantageously, the first clampable portion and the second clampable portion may be at or adjacent to opposing longitudinal ends of the building-façade-element precursor for twisting about a longitudinally central or substantially longitudinally central position of the building-façade-element precursor. As such, uniformly twisted building façade elements can be created.

Beneficially, the first clampable portion and/or the second clampable portion may be away from longitudinal ends of the building-façade-element precursor for permitting twisting about a position away from a longitudinally central or substantially longitudinally central position of the building-façade-element precursor. This may permit for multiple separate twists to be formed in the building-façade element, or at least allows for variability in the shape of the building-façade element.

Preferably, tension may be imparted to the building-façade-element precursor via moving the first and second clamps away from each other. This is a convenient way of forming tension in the precursor, and does not require a separate tensioning means beyond one of the clamps, for example. However, a separate tensioning means may be considered. For example, the precursor may be held by the second clamp, and then pulled using a further clamp to apply tension, with the first clamp then clamping the precursor. In this way, tension could be applied without having the first and second clamps being moveable away from each other.

Additionally, wherein during step d) the second clamp may be rotated relative to the first clamp to provide an initial twist to the building-facade-element precursor whilst the building-facade-element precursor is under said tension, tension may again be imparted to the building-facade-element precursor, and the second clamp is again rotated relative to the first clamp to provide a further twist to the building-facade-element precursor whilst the building-facade-element precursor is under said tension to form the twisted building facade element. When twisting the precursor, the material may deform, strain and/or creep which may reduce the tension on the precursor. Tension is therefore reapplied to avoid rippling of the material.

Preferably, during step b) the building-facade-element precursor is clamped via a fastener. This may require holes formed through the precursor and clamps to permit for the insertion of a fastener.

According to a second aspect of the invention, there is provided an apparatus for forming a twisted building facade element from an elongate building-facade-element precursor comprising metal, the apparatus comprising: a first clamp for releasably clamping a first clampable portion of the building-facade-element precursor; a second clamp for releasably clamping a second clampable portion of the building-façade-element precursor, the second clamp being spaced apart from and linearly aligned with the first clamp; a linear displacement means for linearly displacing the first clamp relative to the second clamp so as to tension the building-facade-element precursor when clamped by the first and second clamps; a rotation means for rotating the second clamp relative to the first clamp so as to twist the building-facade-element precursor when clamped by the first and second clamps and tensioned.

Preferably, the first clamp may be slidable for linearly displacing the first clamp relative 25 to the second clamp.

Additionally, the apparatus may further comprise a first clamp support, the first clamp being moveable relative to the first clamp support via adjustment of at least one fastener for linearly displacing the first clamp relative to the second clamp. For example, the clamp is held to the support via at least one bolt and nut. Tightening of the tensions the bolt which draws the first clamp towards the clamp support and therefore away from the second clamp. This tensions the precursor. The use of a bolt and nut allows for incremental and controlled tensioning of the precursor.

Advantageously, the apparatus may further comprise a biasing means at the fastener for preventing or limiting deformation of the building-facade-element precursor. The biasing means is a spring, and therefore there may be a spring between the nut and the clamp support. As such, when the nut is tightened, the spring is compressed. During twisting of the precursor, the material may deform, strain and/or creep which may tend to reduce the tension on the precursor. The springs, being under compression, helps to maintain tension on the precursor which can prevent or limit rippling of the material.

Beneficially, the apparatus may further comprise a second clamp support, the rotation means comprising a major gear rotatably mounted to the second clamp support and a minor gear for driving the major gear, the second clamp being mounted to the major gear and a handle being connected to the minor gear. The use of gearing allows for manual rotation of the second clamp, even if a large amount of torque is required to be applied due to the stiffness of the precursor.

Additionally, the apparatus may further comprise a ratcheting mechanism for ratcheting the rotation of the major and/or minor gear. This allows for pressure to be reduced or removed from the major and/or minor gear, without allowing the precursor to rebound or untwist due to its resilience. This is useful to permit manual rotation, since it may not be possible to manually maintain a constant holding pressure on the rotation means. This provides safety advantages, since the handle, if present, is prevented or limited from spinning out of control due to rebounding of the precursor.

Optionally, the apparatus may further comprise a bed, the first and/or second clamps being securable to a plurality of locations on the bed. This allows for the accommodation of different sizes of precursor.

According to a third aspect of the invention, there is provided a method of forming a twisted building facade element, the method comprising: providing an elongate buildingfacade-element precursor, the building-facade-element precursor comprising metal and having a first clampable portion and a second clampable portion, the first and second clampable portions spaced apart from each other in a longitudinal direction of the building-facade-element precursor; clamping the building-facade-element precursor at the first clampable portion with a first clamp and clamping the building-facade-element precursor at the second clampable portion with a second clamp; imparting tension to the building-facade-element precursor; rotating the second clamp relative to the first clamp so as to twist the building-facade-element precursor whilst the building-facade-element precursor is under said tension to form the twisted building facade element; and releasing the twisted building facade element from the first and second clamps.

According to a fourth aspect of the invention, there is provided an apparatus for forming a twisted building façade element from an elongate building-façade-element precursor 5 comprising metal, the apparatus comprising: a first clamp for releasably clamping a first clampable portion of the building-façade-element precursor; a second clamp for releasably clamping a second clampable portion of the building-facade-element precursor, the second clamp being spaced apart from and linearly aligned with the first clamp; tensioning means for imparting tension to the building-façade-element precursor 10 when clamped by the first and second clamps; and a rotation means for rotating the second clamp relative to the first clamp so as to twist the building-facade-element precursor when clamped by the first and second clamps and tensioned.

The invention will now be more particularly described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a side view of a first embodiment of an apparatus in accordance with second and fourth aspects of the invention, forming a twisted louvre from a louvre precursor via a method in accordance with first and third aspects of the invention; Figure 2 shows a side view first clamp mounted to a bed of the apparatus of Figure 1; Figure 3 shows an end view of the first clamp of Figure 2; Figure 4 shows a side view of the first clamp mounted to a bed of the apparatus of Figure 1; Figure 5 shows a side view of the first clamp of Figure 4; Figure 6 shows an end view of the first clamp of Figure 4; Figure 7 shows a view of at least part of a rotation mechanism of the first clamp of Figure 4 removed therefrom; Figure 8 shows the engagement of a pawl with a major gear of the rotation mechanism of Figure 7; Figure 9 shows a twisted louvre produced by the apparatus of Figure 1; Figure 10 shows an end view of a second embodiment of an apparatus in accordance with second and fourth aspects of the invention; Figure 11 shows a side view of a portion the apparatus of Figure 10; Figure 12 shows a side view of a further portion of the apparatus of Figure 10; and Figure 13 shows a partial top view of the further portion of Figure 12.

Referring firstly to Figure 1, there is shown an apparatus 10 for forming a twisted or helical building façade element 12 from an elongate building-façade-element precursor comprising metal. The building façade element 12 is preferably a louvre, although it will be appreciated that other building façade elements may be twisted. The term buildingfaçade-element precursor or louvre precursor will be understood to refer to the element which is used to form the building façade element 12 or louvre. The terms workpiece or blank may also be used.

The apparatus 10 comprises a first clamp 14 for releasably clamping a first clampable portion 16 of the building-façade-element precursor and a second clamp 18 for releasably clamping a second clampable portion 20 of the building-façade-element precursor. In Figure 1, reference numerals 16, 20 for the clampable portions of the precursor point to clampable portions of the twisted building façade element 12 since the precursor itself is not shown in the Figures and these clampable portions are correspond.

The first and second clampable portions 16, 20 are here at or adjacent to the ends of the precursor, although it will be appreciated that if at least one of the clamps 14, 18 is arranged to allow the workpiece to extend there-past or therethrough, at least one of the clampable portions may be away from the ends of the precursor. For example, one of the clampable portions may be in a central region of the precursor.

The second clamp 18 is spaced apart from and linearly aligned with the first clamp 14. As such, the precursor can be clamped in each of the first and second clamps 14, 18 and extend therebetween.

The first and second clamps 14, 18 are each mounted to a bed 22, which may also be referred to as a machine bed. The machine bed 22 comprises at least one and preferably 30 two rails 24 or elements. The rails 24 have an upper flange 26a which permits for holes to be made there in to receive bolts 28a therethrough. Whilst described as being mounted to a bed 22, it will be appreciated that this may not be necessary. The rails 24 are preferably I-beams, since this permits for a stable base formed by a lower flange 26b with the upper flange 26a providing the means for extending holes and bolts 28a therethrough. The bed is preferably heavy and therefore the rails 24 may be formed from a dense material, such as steel.

Referring now to Figures 2 and 3, the first clamp 14 is mounted or secured to a first clamp support 30. The first clamp support 30 may otherwise be referred to as an end or a back. The first clamp support 30 includes at least one and preferably a plurality of holes in a lower portion thereof for receiving bolts 28a or fasteners therethrough. The bolts 28a extend through the holes in the bed 22 to secure the first clamp support 30 to the bed 22.

The first clamp support 30 may have two feet 32, which each have the holes therein, for siting on the rails 24, and a body 34 which extends between the two feet 32. However, it 15 will be appreciated that other arrangements for the first clamp support 30 may be considered.

The first clamp 14 includes two jaws 36 or grips. Each jaw 36 has at least one hole therethrough which aligns with a hole in the corresponding jaw 36. The holes permit for a bolt 28b to extend through the jaws 36 to secure and clamp the precursor. It will be appreciated that the clampable portions of the precursor may also include holes aligned with the holes in the jaws to permit for bolts to extend therethrough to improve securement of the precursor. There is preferably a plurality of holes in each jaw 36. Each jaw 36 is L-shaped or substantially L-shaped, having a connection portion 36a to permit securement with the first clamp support 30, and a precursor-engagement portion 36b.

However, it will be appreciated that other jaw shapes or clamping arrangements may be considered.

The apparatus 10 comprises a tensioning means 38 for tensioning the precursor. Here the tensioning means 38 is a linear displacement for moving and holding the first clamp 14 away from the second clamp 18.

The linear displacement means comprises at least one hole, and preferably a plurality of holes, in the first clamp 14 and at least one hole, and preferably a plurality of holes, in the first clamp support 30 which are aligned so that a fastener can be inserted therethrough. As such, a bolt 28c, threaded bar or threaded rod, which is preferably an M12 high tensile bolt 28c, extends through the hole in the first clamp 14 and through the hole in the first clamp support 30. A nut 40 is used on the bolt 28c at the first clamp support 30 which allows for the bolt 28c to be placed under tension so as to draw the first clamp 14 towards the first clamp support 30 and so away from the second clamp 18. Here there are three holes in each jaw 36, in particular the connection portion of each jaw. The holes in each jaw 36 are preferably regularly spaced to ensure uniform loading on the precursor.

The first clamp 14 is preferably mounted to a slider to permit for the linear displacement 10 thereof There may be a box section 42, or intermediate element, between the jaws 36 and the first clamp support 30. There is preferably at least one central hole, and here two central holes, which extend through the box section 42 and the first clamp support 30. A bolt 28d, threaded bar or threaded rod extends through each central hole. Six lateral or periphery holes corresponding to the positions of the bolts 28c which attach the jaws 36 and the first clamp support also extend through the box section 42 for receiving said bolts 28c thereth rough.

There are here two rear plates 43 at a rear side of the first clamp support 30. Bolts 28c, 28d which extend through the box section 42 also extend through the rear plates 43.

A biasing means, such as a spring 44, is positioned over each of the bolts 28d which extend through the central holes.

It will be appreciated that the box section, bolts, holes, and springs may be omitted, or springs may be used on the other bolts 28c which tension the precursor.

Referring now to Figures 4 to 6, there is shown the second clamp 18 which is mounted or secured to a second clamp support 46. The second clamp support 46 is preferably similarly or identically formed as the first clamp support 30, having two feet 32a, which each have the holes therein, for siting on the rails 24, and a body 34a which extends between the two feet 32a. Here the second clamp support 46, and specifically each foot 32a, preferably includes a gusset 48 or brace which extends in a direction towards the first clamp 14 along the bed 22 so as to prevent or limit the second clamp support 46 from bending.

The second clamp 18 is preferably similar or identical to the first clamp 14, having two L-shaped jaws 36c with holes extending through one part 36d of the jaws to allow clamping of the precursor and holes extending through another part 36e of the jaws 36 to allow connection with the second clamp support 46.

The apparatus 10 includes a rotation means 50 or mechanism for rotating the second clamp 18. Here, each jaw 36 is secured to an intermediate plate 42a which is attached to a major wheel or gear 52, preferably to the axis of rotation of the major gear 52.

The major gear 52 is roatably mounted to the second clamp support 46. A handle 54 is used to allow for manual rotation of the second clamp 18.

To permit convenient manual rotation of the second clamp 18, gearing is used. The gearing is illustrated in Figure 7. A minor wheel or gear 56 is rotatably mounted to the second clamp support 46. The minor gear 56 includes teeth which interlock with teeth on the major gear 52. The handle 54 is connected to the minor gear 56 so that rotation of the minor gear 56 drives the major gear 52. The gearing is preferably such that for every rotation of the minor gear 56, the major gear 52 rotates by five degrees. However, it will be appreciated that other gearing may be considered, or gearing may not be required. Additionally, a handle for manually driving the rotation may not be required, and the rotation may be electrically driven by an electric motor, for example.

To prevent unintentional counter-rotation of the second clamp 18, which may be caused by the stiffness and elasticity of the precursor, a ratcheting mechanism 58, or other means or another mechanism for preventing counter-rotation, is preferably used. The ratcheting mechanism 58 can preferably be moved from an engaged or active condition to a released or passive condition, so that counter-rotation is permitted when required. More preferably, the ratcheting mechanism 58 is reversible, so as to permit rotation in either direction and prevent rotation in the opposing direction as required.

The ratcheting mechanism 58 includes a pawl 60 which is pivotably or rotatably mounted to the second clamp support 46. The pawl 60 preferably has first and second heads 62, 64 which face opposing directions, each head having teeth 66 to interlock with those of the major gear 52, although it will be appreciated that the pawl 60 may engage with the minor gear 56. The pawl 60 is arranged so as to be gravity biased into engagement with the major gear 52, although, it will be appreciated that spring 44 biasing or other biasing may be considered.

Referring in addition to Figure 8, the teeth 66 of the pawl 60 are sloped on one side 66a and flat on the other 66b. The slope 66a of the teeth 66 allows for the pawl 60 to move over the teeth of the major gear 52 in one direction, and the flat 66b of the teeth 66 prevents the pawl 60 from moving over the teeth 66 of the major gear 52 in the other 5 direction. The pawl 60 can be rotated so as to switch the head 62, 64 which engages with the major gear 52. When a first head 62 of the pawl 60 engages with the major gear 52 it permits rotation in a clockwise direction and prevents or limits rotation in the anticlockwise direction. When a second head 64 of the pawl 60 engages with the major gear 52, it permits rotation in the anti-clockwise direction and prevents or limits rotation in the 10 clockwise direction.

Whilst a two-headed pawl 60 is suggested, it will be appreciated that this may not be necessary. For example, there may be two different pawls for controlling rotation in either direction, each pawl being selectably engageable with the major gear. Alternatively, a ratchefing mechanism for both directions of rotations may not be required. A ratchefing mechanism may not be required at all if the material being used does not exert a high counter-rotation force to being twisted, for example if the material is not stiff and/or highly elastic.

To produce a helical or twisted louvre 12, as per Figure 9, a workpiece, louvre precursor or building-facade-element precursor may be provided. The louvre precursor is preferably elongate, although non-elongate shapes may be considered, and is more preferably planar or substantially planar. In this way, the louvre precursor is an elongate sheet. The sheet is preferably in the range of thickness between 2 mm and 10 mm, and is more preferably 6 mm or substantially 6 mm. The width of the sheet is preferably in the range of 100 mm to 500 mmm, and more preferably has a width of 150 mm, 200, mm, 250 mm or 400 mm. The length of the sheet may be any as desired, for example within the range of 2 m to 8 m.

The louvre precursor or building-facade-element precursor preferably comprises, consists essentially of, or consists of metal, although it will be appreciated that deformable non-metals may also be considered if they are considered to be non-combustible. More particularly, the metal is aluminium, such as an alloy of aluminium of which at least a majority is aluminium. The aluminium alloy is preferably heat treated according to a T4 or T6 aluminium heat-treating temper code, although other types of aluminium alloys or other pre-treatments or tempering may be considered. The aluminium alloy is most preferably 6063 14. Although aluminium is preferred, it will be appreciated that other metals, such as steel or titanium alloys, or composite materials may be considered.

The clampable portions 16,20, which are here the end portions of the louvre precursor, 5 preferably have holes machined therethrough for receiving bolts 28b, which are preferably M12 high tensile bolts, passed through the holes in the jaws 36. In this way, the clampable portions 16,20 can be secured to the jaws 36.

The second clamp support 46 may be secured on the rails 24, for example via bolts 28a passing through the holes in the feet 32a of the second clamp support 46 and through 10 the holes in the rails 24.

The first clamp 14 is moved away from the first clamp support 30 via loosening the nuts 40 on the fasteners which attach the first clamp 14 to the first clamp support 30 and sliding the first clamp 14 away from the first clamp support 30. The first clamp support 30 is then positioned on the rail 24 so that the distance between the first and second clamps 14, 18 equates or substantially equates to the length of the louvre pre-cursor. The first clamp support 30 is secured to the rails 24 via fasteners 28a inserted through holes in the feet 32 and holes in the rail 24. Holes may be required to be drilled into the correct position on the rail 24 to accommodate the fasteners. The first clamp support 30 and the second clamp support 46 may be secured via M16 bolt and nuts 40.

The first clamp 14 is rotated so as to be angularly aligned with the second clamp 18. The louvre precursor is then secured in the clamps 14, 18 by inserting the clampable portions 16, 20 into the jaws 36, 36c and inserting fasteners 28b through the holes in the first and second jaws 36, 36c and the holes in the clampable portions 16, 20. The fasteners 28b are tensioned via nuts so that the jaws 36, 36c clamp the louvre precursor.

The louvre precursor is then tensioned. This is done via moving the first clamp 14 away from the second clamp 18, which is achieved by the linear displacement means. In other words, the nuts 40 on the bolts 28c which connect the first clamp 14 to the first clamp support 30 are tightened. This is preferably done in a specific way to reduce the risk of the first clamp 14 binding in the slider. Firstly, the nuts 40 are screwed up to the first clamp support 30 with no tension, and then the nuts 40 are individually tightened. Preferably, the nuts 40 are tensioned in the following order: top left, bottom right, bottom left, top right, centre left, centre right. The two central nuts on the central bolts 28d are also tensioned which compresses the springs 44. Each nut 40 is preferably tensioned in stages. The final tension for each nut 40 is preferably 110 Nm or substantially 110 Nm, although other tensions may be considered, such as in the range of 50 Nm to 150 Nm. The louvre precursor is thus under tension. Since the precursor is tensioned so that it will be under tension during twisting, this prevents or limits the louvre precursor from rippling, crimping, crumpling, or otherwise deforming at the longitudinal edges thereof when twisting and/or when being released from the clamps 14, 18.

The second clamp 18 is then rotated via the rotation mechanism 50. To rotate the second clamp 18, the first or second head of the pawl 60 is engaged with the major gear 52, depending on the desired direction of rotation, and then the handle 54 is rotated to rotate the minor gear 56, which drives the major gear 52, which rotates the second clamp 18. The first clamp 14 remains stationary and therefore there is relative rotation between the first and second clamps 14, 18.

The second clamp 18 is rotated by an initial amount, for example by 90 degrees. The louvre precursor is thus twisted about a central point between the first and second clamps 14, 18. During rotation, the louvre precursor material may stretch, creep, strain or otherwise deform. Such stretching may occur at the outward longitudinal edges of the precursor. The stretching relives tension in the precursor.

The use of springs 44 on the central bolts or bars 28d under compression by the nuts 40 can maintain some tension on the precursor and reduces the risk of the rippling at the longitudinal edges of the precursor due to insufficient tension. However, the tension should preferably still be reapplied to avoid or reduce the risk of the rippling at the longitudinal edges of the precursor due to insufficient tension. Here the reapplication of tensioning is achieved by tensioning the nuts 40 on the bolts 28c which attaches the first clamp 14 to the first clamp support 30. The nuts 40 should be re-tensioned, for example to 110 Nm. During this re-tensioning, the ratcheting mechanism 58 holds the second clamp 18 in position.

The second clamp 18 can then be rotated by a further amount. For example, the second clamp 18 may be rotated by a further 130 degrees so that the total rotation is 220 degrees. It is possible that further re-tensioning may be required or desirable during this further rotation of the second clamp 18. Retensioning may generally be done approximately halfway through the twisting.

Although here a louvre with a 180 degrees twist is desired, the second clamp 18 is rotated to 220 degrees to provide over-twist which may be necessary to compensate for the elasticity of the material of the louvre.

The ratchet mechanism is then released. Here, the pawl 60 is rotated so that the second 5 head 64 engages the major gear 52, although it will be appreciated that ratcheting in the counter-rotation direction may not be necessary. The handle 54 should be held to avoid sudden counter-rotation since the ratchet mechanism is no longer preventing or limiting counter-rotation. Sudden counter-rotation may cause deformation of the louvre precursor and/or may pose a safety hazard to personnel in the vicinity due to the movement of the 10 handle 54 or precursor.

The holding pressure on the handle 54 can then be reduced and so the precursor is allowed to gradually rebound. This may reduce the elastic shear strain or torsional strain in the precursor. Once the elastic shear strain has been released, the twisted louvre 12 is formed, and here has a 180-degree twist.

The twisted louvre 12 may need to be supported, for example via wooden blocks, and the tension on the louvre 12 should be removed by loosening the nuts 40 which secure the bolts 28c which hold the first clamp 14 to the first clamp support 30. Loosening of the nuts 40 should preferably be done in the reverse order to that which they were tightened. The twisted louvre 12 can then be removed from the clamps 14, 18 via removing the fasteners 28b which held the louvre 12 in the jaws 36, 36c.

The twisted louvre 12 may then undergo post processing as required, for example polyester powder coating to give the appearance of rust, or painting.

The aforementioned method and apparatus 10 permits for twists performed about a centre point of the louvre, although to achieve non-central twists a second embodiment 25 of the method and apparatus 10 may be required.

Referring now to Figures 10 to 12 the second embodiment of the apparatus 110 is shown. The second embodiment has similar or identical features to first embodiment and referencing numerals are similar or identical with 100 added.

The second embodiment includes a first clamp 114 and a second clamp 118 which are 30 similar or identical to the first and second clamps 114, 118 of the first embodiment and are mountable to rails 124 in a similar or identical way. The second embodiment includes at least one, and preferably first and second intermediate clamps 170, 172. The intermediate clamps 170, 172 are for clamping the louvre precursor away from the ends of the louvre precursor, for example clamping the louvre precursor in clampable portions 16, 20 in a central region thereof.

Each of the first and second intermediate clamps 170, 172 includes two jaws 136. The jaws 136 of the first and second intermediate clamps 170, 172 are preferably at least in part deformable or resilient. This permits a reduction or relief in tension as the louvre precursor is twisted. As such, the jaws 136 are preferably formed from timber and/or have an elastomeric or rubber coating, for example ethylene propylene diene monomer rubber. Additionally or alternatively, to provide such reduction or relief in tension, the intermediate jaws 136 are mounted via biasing means, such as springs 144. The first and second intermediate clamps 170, 172 are preferably supported by first and second intermediate clamp supports 174, 176, which are mountable and/or movably mountable to the rails 124 in a similar or identical way to the first and second clamp supports of the preceding embodiment.

The first intermediate clamp 170 may be rotatably mounted to the first intermediate clamp support 174 in a similar or identical way to the mounting of the second clamp 118 to the second clamp support 146. As such, the first intermediate clamp includes a similar rotation mechanism 178. The rotation mechanism 150 of the second clamp 118 and the rotation mechanism 178 of the first intermediate clamp are linked via a linkage 180 so that they rotate together.

To use the second embodiment, the intermediate clamps 170, 172 are positioned so that the associated jaws 136 can clamp the precursor at the desired location of the centre of the twist. For example, the centre of the twist may be defined between the jaws 136 of the intermediate clamps 170, 172. The precursor is clamped via the first and second clamps 116, 118 and the precursor is tensioned via the first clamp 116 in a similar way to the first embodiment.

The jaws 136 of the intermediate clamps 170, 172 are then engaged with the precursor. This is achieved via loosening nuts 140 which hold the springs 144 under compression. 30 The jaws 136 of each clamp 170, 172 therefore move towards each other to gently or loosely clamp the precursor.

The second clamp 118 is then rotated in a similar way to the first embodiment and the first intermediate clamp 170 rotates with it. A twist therefore forms in the precursor, centred around a point between the jaws 136 of the intermediate clamps 170, 172. Since the springs 144, elastomeric coating and/or timber jaws are used, the twist that forms is fluid and sharp deformation in the precursor is avoided.

Retensioning and overtwisfing of the precursor during use of the second embodiment 5 may be considered as per the first embodiment.

It is therefore possible to provide a method and apparatus for forming a twisted louvre or other building façade element. The application of tension to the workpiece whilst twisting prevents or limits rippling at the outward edges of the workpiece. As such, suitable decorative louvres can be formed from non-combustible or fire-resistant material.

The words 'comprises/comprising' and the words 'having/including' when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components, but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

The embodiments described above are provided by way of examples only, and various 20 other modifications will be apparent to persons skilled in the field without departing from the scope of the invention as defined herein.

Claims

Claims 1 An apparatus for forming a twisted building façade element from an elongate building-façade-element precursor comprising metal, the apparatus comprising: a first clamp for releasably clamping a first clampable portion of the building-façade-element precursor; a second clamp for releasably clamping a second clampable portion of the building-façade-element precursor, the second clamp being spaced apart from and linearly aligned with the first clamp; at least one intermediate clamp between the first and second clamps for clamping an intermediate clampable portion of the building-façade-element precursor, the intermediate clampable portion being between the first and second clampable portions; a linear displacement means for linearly displacing the first clamp relative to the second clamp so as to tension the building-façade-element precursor when clamped by the first and second clamps; a rotation means for rotating the second clamp relative to the first clamp so as to twist the building-façade-element precursor when clamped by the first and second clamps and tensioned.
2 An apparatus as claimed in claim 1, wherein there are first and second intermediate clamps each for clamping a separate intermediate clampable portion.
3. An apparatus as claimed in claim 2, wherein the first intermediate clamp is rotatable with the second clamp.
4 An apparatus as claimed in claim 2 or claim 3, wherein the first and second intermediate clamps each have jaws which are at least in part deformable or resilient.
An apparatus as claimed in any one of the preceding claims, wherein the first clamp is slidable for linearly displacing the first clamp relative to the second clamp.
6 An apparatus as claimed in any one of the preceding claims, further comprising a first clamp support, the first clamp being moveable relative to the first clamp support via adjustment of at least one fastener for linearly displacing the first clamp relative to the second clamp.
7 An apparatus as claimed in claim 6, further comprising a biasing means at the fastener for preventing or limiting deformation of the building-façade-element precursor.
8 An apparatus as claimed in any one of the preceding claims, further comprising a second clamp support, the rotation means comprising a major gear rotatably mounted to the second clamp support and a minor gear for driving the major gear, the second clamp being mounted to the major gear and a handle being connected to the minor gear.
9. An apparatus as claimed in claim 8, further comprising a ratcheting mechanism for ratcheting the rotation of the major and/or minor gear.
10. An apparatus as claimed in any one of the preceding claims, further comprising further comprising a bed, the first and/or second clamps being securable to a plurality of locations on the bed.
11. A method of forming a twisted building façade element, the method comprising: a) providing an elongate building-façade-element precursor, the building-façade-element precursor comprising metal and having a first clampable portion, a second clampable portion, and at least one intermediate clampable portion, the first and second clampable portions spaced apart from each other in a longitudinal direction of the building-façade-element precursor, and the or each intermediate clampable portion being between the first and second clampable portions; b) clamping the building-façade-element precursor at the first clampable portion with a first clamp, clamping the building-façade-element precursor at the second clampable portion with a second clamp, and clamping the intermediate clampable portion with an intermediate clamp; c) imparting tension to the building-façade-element precursor via the first and second clamps; d) rotating the second clamp relative to the first clamp so as to twist the buildingfaçade-element precursor whilst the building-façade-element precursor is under said tension to form the twisted building façade element; and e) releasing the twisted building façade element from the first and second clamps.
12. A method of forming a twisted building façade element, the method comprising: a) providing an elongate building-façade-element precursor, the buildingfaçade-element precursor comprising metal and having a first clampable portion and a second clampable portion, the first and second clampable portions spaced apart from each other in a longitudinal direction of the building-façade-element precursor; b) clamping the building-façade-element precursor at the first clampable portion with a first clamp and clamping the building-facade-element precursor at the second clampable portion with a second clamp; c) imparting tension to the building-façade-element precursor; d) rotating the second clamp relative to the first clamp so as to twist the buildingfaçade-element precursor whilst the building-façade-element precursor is under said tension to form the twisted building façade element; and e) releasing the twisted building façade element from the first and second clamps.
13. An apparatus for forming a twisted building façade element from an elongate building-façade-element precursor comprising metal, the apparatus comprising: a first clamp for releasably clamping a first clampable portion of the building-façade-element precursor; a second clamp for releasably clamping a second clampable portion of the building-façade-element precursor, the second clamp being spaced apart from and linearly aligned with the first clamp; tensioning means for imparting tension to the building-façade-element precursor when clamped by the first and second clamps; and a rotation means for rotating the second clamp relative to the first clamp so as to twist the building-façade-element precursor when clamped by the first and second clamps and tensioned.