A method of strengthening a panel and a method of forming a panel

Abstract

A method of strengthening a panel 10 having an open structure and a plurality of sides extending from a main surface includes placing the panel on top of an insert (16, fig 2) on top of a rigid suppor

Description

The present invention relates to a method of strengthening a panel and relates particularly, but not exclusively, to strengthening a metal panel for use on the outer walls of buildings as cladding. The use of decorative panels on the outside of buildings is well known. Exterior panels are generally made of metal and are commonly used for the refurbishing of old buildings or as a feature for new buildings providing an attractive aesthetic exterior surface. It is important that panels appear to be consistent, and areas of imperfection or damage are avoided or are not immediately apparent. Using thin sheet materials makes such panels vulnerable to denting or similar imperfections caused by impacts. The risk of damage and imperfections can be reduced by forming the panels from thicker material or by using reinforcement of a thinner metal surface. However, this increases the material required to form the panel. This in turn increases the cost of production and also increases the cost of installation with more robust fixings being required and more personnel and equipment needed to handle the panels. Preferred embodiments of the present invention seek to overcome or alleviate the above described disadvantages of the prior art. According to an aspect of the present invention there is provided a method of strengthening a panel, comprising the steps : providing a panel having an open structure and having a plurality of sides extending from a main surface; providing an insert and providing a rigid support surface; placing said panel on top of said insert on top of said rigid support surface in a bag; substantially sealing said bag; removing air from said bag such that air pressure outside said bag is sufficiently greater than air pressure inside said bag so as to cause a surface of said bag in contact with said main surface of said panel to permanently deform over said insert; removing said panel from said bag. By deforming the panel over the insert causes the panel to gain strength and structural integrity. This deformation and therefore strength negates the need to increase the thickness of the metal. Therefore, keeping costs and the weight of the panel down by reducing the thickness but increasing the structural integrity. Furthermore, by having a panel which does not have a planar main surface the advantage is provided that small amounts of damage caused during or after installation or imperfections resulting from the manufacturing process are less immediately apparent when a multiplicity of panels are installed on a wall. As a result, a thinner material can be used because concerns regarding damage and imperfections are reduced as well as because the structural integrity of the panel has been improved by the inclusion of the de formation of the planar surface. The removal of the need for reinforcement not only reduces the weight of the panel but also removes or reduces the need for the inclusion of potentially dangerous flammable materials such as plastics which have been commonly used in the reinforcement of lightweight metal panels. In a preferred embodiment the method further comprises removing air until a predetermined pressure is achieved. Turning the pump off at a predetermined pressure ensures that the deformation in a series of panels is substantially uniform across all of those panels. In a further embodiment the insert is moveable relative to said board. Having a moveable insert allows you to produce a random deformity by moving the position of the insert or by replacing the insert with a different shape. As a result, it is possible to create a series of unique panels by using one of several randomly positioned inserts or by using a single insert and moving it into random positions. This creates an aesthetically pleasing exterior surface to a building and the random nature of the main surface means that minor damage or manufacturing imperfections are not immediately obvious without engaging in close inspection of the panels. It is therefore less likely that a panel will need replacing and panels can be manufactured from thinner materials or without the reinforcement of the metal surface . In a further preferred embodiment, the insert is fixed onto said board. Having the insert fixed allows for the same deformation to be made across all panels. In an additional preferred embodiment, the panel is cuboid in shape, the cuboid has one open face, and the open face comprises an aperture extending through the face. In another preferred embodiment the air is removed from said bag using a vacuum pump. The use of the vacuum pump allows for a more precise measurement of the air pressure. The method may further comprises providing at least one pointed corner with a corner cover so as to increase the radius of a curve of said pointed corner. In an additional preferred embodiment, the main surface has an area greater than one of either sides. In another preferred embodiment the bag creates a seal between said board and the edges of said panel. According to another aspect of the present invention there is provided a method of forming a panel, comprising the steps: forming a panel; and applying the strengthening method as set out above. Preferred embodiments of the present invention will now be described, by way of example only, and not in any limitative sense with reference to the accompanying drawings in which:- Figure 1 is an image of a pair of panels produced by the method of the present invention; Figure 2 is an image of a former used in the method of the present invention; Figure 3 is an image of a panel placed on top of the former shown in figure 2; Figure 4 is a close-up image of a corner of the panel shown in figure 3; Figure 5 is an image of the panel shown in figure 3 with protective coverings used in the method of the present invention; Figure 6 is an image of the panel shown in figure 3 inside a vacuum bag used in the method of the present invention; Figure 7 is an image of the panel shown in figure 3 deforming around the insert shown in figure 2 as part of the method of the present invention; and Figure 8 shows further examples of finished panels produced using the method of the present invention. Referring initially to figure 1 the method of the present invention is used to form a panel 10 having a deformation 12, the panel having been formed to provide an aesthetic decoration when attached to a structure, such as a building 14. Referring now to figures 2 to 5, the method is undertaken by utilising the following steps, an insert 16 is placed on a rigid support surface 18, such as a wooden board. The insert 16 has an outer frame 20 having four sides constructed from angle iron which has an L-shaped cross-section. A first pair of longer sides 22 are located opposite each other, whilst a second pair of shorter sides 24 are located between the first pair 22, with all four edges being welded together to form a rectangular shape. Located inside the rectangular frame is a pair of flat bar iron insert structures 26. The insert structures 26 are welded at one end to the inside surface of one of the first sides 22 and the other end attached to the inside surface of the other first side 22. The position and the angle at which the insert structures are at will directly affect the shape of the deformation 12 on the panel 10. It should be noted that only one insert structure 26 could be used or more than two. The insert structures could also be free to move instead of being welded in place, in which case angle iron is used and / or piece are joined together to be free standing. Furthermore, the insert structures could be any shape or size, for example a metal block or bar (that would not necessarily need an outer frame). This block or metal structure could be placed anywhere on the wooden board with the panel 10 placed over it. The panel 10 shown in the figures is cuboid in shape where the height and length are much larger than the width. The panel has a rectangular main surface 28, a plurality of sides 29 extending perpendicular from the four edges of the main surface 28 and a rim 32 extending from each of the four sides 29. It can also be seen in figure 4 that the sides of the panels are not welded together. Surrounding the four sides 29 is an open face, opposite the main surface 28 giving the cuboid shape an open structure. The height, length and width of the panel 10 are only slightly larger than the height, length and width of the insert structure 16. A guide 30 is further used in this example and fixed on top of the rigid support 18. The purpose of the guide is to provide a standard edge against which the panels 10 can be positioned to ensure a consistent location as the process is repeated for each panel. The guide 30 is fixed to the board 18. Once the panel 10 is placed over the insert 16 each corner of the panel 10 and the guide 30 is covered with a corner cover 34 as shown in figure 5. The corner covers 34 are formed from sections of foamed thermoplastic and held in position using tape. However, any suitable material can be used that increases the radius of the corner of panel 10 or guide 30 to reduce the risk of tearing. Referring now to figures 6 and 7 the rigid support 18, insert 16, panel 10 and guide 30 are all placed inside a vacuum bag 36. The vacuum bag 36 has one opening that is sealed using a long clamp (not shown) . The clamp is formed in two parts including a central rod and a split tube. It should be noted that the bag could be sealed by other methods. The vacuum bag 36 also has an aperture (not shown) that enables a pump hose to be inserted and sealed. This pump hose is attached to a vacuum pump 38. The vacuum pump 38 is used to remove the air from within the vacuum bag to create a much lower air pressure within the bag compared to outside the bag. Once a permanent deformation 12 has been created the vacuum pump 38 is turned off and the panel 10, with these deformations 12 being clearly shown in figure 7, is formed. The method of strengthening the panel 10 will now be described. A panel 10 of suitable colour (matt or shiny), size and type of metal is chosen. The shape and size of the insert 16 is also chosen and a decision is made to whether a series of similar panel deformations will be created or if random deformations will be created. If a series of similar deformations is to be obtained, the guide 30 is placed and then fixed onto the rigid structure 18, in this case a wooden board. The insert 16 is positioned on the wooden board 18 and positioned correctly using the guide 30. The insert and insert structures 26 could also be fixed if the same pattern is to be achieved across many panels. The open face of the desired panel 10 is placed over the insert 16 and also positioned correctly using the guide 30. All corners of the guide 30 and the panel are covered with a corner covers 34. These are used to protect the vacuum bag 36 from tears during the air removal process. The wooden board 18, insert 16, guide 30 and panel 10 are inserted into the vacuum bag 36 and placed on top of a table or the floor. The vacuum bag 36 is sealed at the open end. Using the central rod and split tube this is achieved by placing the rod onto the bag a short distance from the open end. The bag is folded over the rod and the split tube is then slid onto the rod to sandwich both sides of the bag between the inside of the split tube and the outside of rod thereby sealing the open end of the bag. One end of the pump hose is inserted into the aperture of the vacuum bag and further sealed whilst the other end of the pump hose is inserted into the vacuum pump 38. The vacuum pump 38 is turned on and the air is removed from within the vacuum bag 36. When the air pressure outside the bag is sufficiently greater than air pressure inside the bag this causes a surface of the vacuum bag to make contact with the main surface of the panel 10. As the air pressure within the vacuum bag further decreases the last amount of air to be extracted is within the space between the wooden board 18 and the panel 10. This begins to form a seal around the edges between the wooden board 18 and the panel 10 and the vacuum bag 36 begins to deform the panel over the insert 16. Once the panel has deformed to the point that a permanent change has been made the vacuum pump can be turned off. If an exact air pressure is known for creating a particular depth or length of permanent deformation the pump can be turned off that this point. The seal at the open end of the vacuum bag 36 is released and the wooden board 18, insert 16, guide 30 and panel 10 are removed from the vacuum bag. The corner covers 34 are removed and the panel is lifted off the insert 16. Any covering on the panel can be peeled off, highlighting the deformations 12 created across the main surface 28 of the panel 10. Figure 8 highlights the different styles and colours of panels 10 that can be used with varying degrees of deformations 12 across their surfaces. In summary, the first step of the method is to provide a panel with an open structure with a plurality of sides extending from a main surface. The panel is placed on top of an insert which is itself on top of a rigid support surface ad put into a bag. The bag is sealed and the air removed from the bag so that air pressure outside the bag is sufficiently greater than the air pressure inside the bag so as to cause the main surface of said panel to permanently deform over the insert. When the panel is removed from the bag, the rigidity of the panel has increased. It will be appreciated by persons skilled in the art that the above embodiments have been described by way of example only and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the protection which is defined by the appended claims. For example, the insert and insert structures have been described above as being made of metal. However, any material that would be strong enough to withstand the air pressure and weight of the panel during the deformation process could also be used.

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