Abstract:
A method of connecting a panel ( 50 ) to a panel joining member ( 51 ) is disclosed. The method includes the steps of forming a recess ( 16 ) adjacent to an edge of a panel. The panel ( 50 ) is located within a panel joining member ( 51 ) the panel ( 50 ) being located against a stop member ( 15 ) and the recess ( 16 ) being aligned with an aperture ( 18 ) in the wall ( 13 B) of the joining member ( 51 ). A fastener ( 17 ) is passed through the aperture ( 18 ) and urges the panel towards the outer wall ( 15 ) of the joining member ( 51 ). A receiver ( 30 ) is inserted into the recess ( 16 ) to assist engagement of the panel ( 50 ) with the fastener ( 17 ). The receiver ( 30 ) has a shape complementary to that of the recess ( 16 ). Opposing walls ( 13 A,  13 B) of the joining member ( 51 ) are inclined towards one another to improve panel retention. A push or snap-fit join is included to facilitate assembly.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a joining member for holding together two or more panels. The invention further relates to a method of assembling said panels to construct, for example, structural or partition walls, flooring and roofing, furniture, containers or luggage. 
   BACKGROUND OF THE INVENTION 
   The assembly of large scale articles such as partition walls, furniture and transport containers by joining together smaller units, particularly panels, is well known in the art. Depending on the nature of the joint between adjacent units, articles of different strengths and function can be produced. For example, where a partition wall is to be formed, the individual units need to be retained in the desired orientation, but need not necessarily be required to be joined together in a robust fashion to withstand impacts. 
   Where, however the units are to form part of a container, and particularly where the article is an item of luggage, the joints usually need to be able to withstand a large amount of strain from the weight of the contents and be able to stand up to, for example, airport luggage handling techniques, which can often involve the luggage receiving a number of impacts. 
   In the art, it has been a standard approach when joining panels together to insert a panel into a moulded extrusion and secure the panel in place by a fastening method such as gluing, riveting or screwing through the outer face of the outer wall of the extrusion into the face of the panel. The screw bites into the panel and as the screw is tightened the panel is drawn into contact with the inner face of the extrusion&#39;s outer wall. 
   The above approach has a number of drawbacks. Firstly, the stress from tightening the screw is concentrated on the outer wall of the extrusion and panel skin. Where, for example, the panels form part of a piece of luggage or cladding on a building, then the sealing joint between the panel and extrusion will be less efficient and the exterior appearance of the joint will not be so pleasing. Also, if the panel width is narrower than the extrusion&#39;s channel width, then additional packing, adhesive bonds or the like may be required between the face of the panel and the extrusion&#39;s walls to maintain the spatial relationship between the panel and the extrusion&#39;s wall. 
   It is an object of the present invention to seek to alleviate the above problems. 
   SUMMARY OF THE INVENTION 
   According to a first aspect of the invention, there is provided, a method of connecting a panel to a panel joining member, the method including the steps of:
     forming a recess adjacent an edge of a panel;   locating said panel edge within a panel receiving portion of a panel joining member;   locating said panel against a stop member and aligning the recess with a fastener aperture formed in an inner wall of the panel receiving portion;   inserting a fastener through the aperture into the corresponding recess in the panel, the fastener urging the panel towards the outer wall of the panel receiving portion. The panel can be easily inserted into the joining member and undesirable stresses in the panel are minimised.   

   Preferably, a receiver is inserted into the recess prior to the panel being located within the panel joining member. 
   Advantageously, an adhesive is introduced between the panel and one or more walls of the joining member to increase the strength of the joint. Optionally, an adhesive bond weld is introduced when the fastener has been tightened substantially. 
   Optionally, the fastener is an expanding rivet fastener to engage the panel tightly. Advantageously, the fastener has a screw-thread to engage the panel and/or panel joining member. 
   Preferably, the fastener receiver is an adapter, the adapter having a shape complementary to that of the recess. The adapter provides a substrate for the screw to grip. The recess optionally narrows away from its open end to ensure that the material from which the adapter is formed undergoes plastic flow around the thread as the threaded fastener is tightened. The material which flows reduces the transmission of any vibrations to the fastener arising, for example from transportation. The vibrations act to cause the screw to loosen and hence the joint to become weaker. 
   Preferably the fastener is introduced into the fastener receiver at an angle inclined to the axis perpendicular to the surface of the panel. The angle encourages greater engagement of the panel or the fastener receiver with the fastener and can urge the panel against the stop members. 
   The or each panel optionally includes one or more projections to engage a corresponding recess in a panel joining member thereby forming a push-fit type joint. The use of push-fit joint enables rapid assembly together of panels which assembly can be accomplished with relatively unskilled labour. Advantageously, opposing walls of the panel joining member are inclined together at an angle of up to 5°. The incline angle is particularly advantageously 0.7° to 2°. 
   The or each panel joining member preferably includes a chamfered edge to facilitate insertion of a panel into the panel joining member. 
   According to a further aspect of the invention, there is provided a panel joining member comprising a joining element having at least one panel receiving portion and at least one fastening assembly,
     the or each fastening assembly comprising a fastener and a fastener receiver, wherein the or each panel receiving portion is defined by spaced opposing walls including a panel stop member, located on at least one of the inner facing surfaces of said opposing walls, and in which a fastener aperture is located through one of said spaced opposing walls.   

   Preferably, where two panel receiving portions subtend an angle of less than 180°, the fastener aperture is located in the internal wall of the joining member. 
   This arrangement facilitates the alignment of a panel against a stop member to position a panel for securing thereto by said fastening assembly. 
   Advantageously, the fastener receiver of the fastener assembly is secured within a panel along a selected panel edge for inserting into a panel receiving portion. The fastener receiver would normally be profiled in a manner to facilitate its correct orientation for insertion into the said panel. 
   In one arrangement, the fastener receiver comprises a body adapted for engagement with a panel, the body including an open mouthed recess for receiving a fastener. 
   Optionally, the recess narrows away from the open mouth. 
   Preferably, the fastener is a screw having a flat ended shank. 
   According to a yet further aspect of the invention there is provided an adapter to receive a fastener for insertion into a panel recess, the adapter comprising a first opening having a diameter greater than that of said fastener. Optionally, the opening is narrower at its closed end to grip the end of a fastener. Advantageously, both the first opening and the narrowing are cylindrical, with the cylinders optionally co-axial. 
   According to a still yet further aspect of the invention, there is provided a panel joint, the panel joint comprising;
     a panel an edge of which is locally flat and which flat region includes a recess;   a joining member, the joining member having spaced opposed walls to receive the panel;   one or more stop members against which a panel is aligned;   the joining member having an aperture in one of said walls to enable a fastening member to pass through the joining member and engage the panel, thereby urging the panel against the opposite wall of the joining member.   

   Advantageously, the joint includes adhesive between the panel and one or more walls of the joining member to increase the strength of the joint. Optionally, the joint further includes an adhesive bond weld. 
   Preferably, an adapter is located in the recess, the adapter having a shape complementary to that of the recess. The adapter optionally narrows away from its open end to ensure that the material from which the adapter is formed undergoes plastic flow around the fastening member as the fastening member is fully engaged. The material which flows reduces the transmission of any vibrations to the fastening member arising, for example from transportation. The vibrations act to cause the fastening member to loosen and hence the joint to become weaker. Preferably, the fastening member includes a screw thread to engage the joining member. 
   Conveniently, the recess includes an aperture to receive a nut into which the fastening member can be screwed, the member and the nut co-operatively engaging to lock the nut against the inner wall. The compressive pre-load force is maintained by the elastic spring effect of the inner-wall. 
   Preferably the fastening member is aligned along an axis which is at an angle inclined to the axis perpendicular to the surface of the panel. The angle causes greater engagement of the fastening member with the material into which it is being screwed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described with reference to the accompanying drawings which show by way of example only three embodiments of a joint for panels. In the drawings: 
       FIG. 1  is a sectional view through a first embodiment of a joint; 
       FIG. 2  is a sectional view through a second embodiment of a joint showing the arrangement just after the locating/fastening screw has been introduced; 
       FIG. 3  is a sectional view through the second embodiment of the joint showing the fastening means fully engaged; 
       FIG. 4  is a plan view of a retention adapter, 
       FIG. 5  is a sectional view through a joint having a snap or push-fit fastening; 
       FIG. 6  is a sectional view through a further joint having a snap or push-fit fastening; and 
       FIG. 7   a - e  illustrates elements of a panel. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring initially to  FIG. 1 , this shows a first embodiment of a coupling means for securing panels together to form an article. The panels can be used in the construction of containers such as hand-portable cases or those which are to contain larger loads to be transported on lorries or ships. The containers are of modular construction and can be easily assembled either by the panel manufacturer or at a separate production site. Alternatively, panels can be joined together to form, for example, a partition wall. 
   The coupling means shown in  FIG. 1  comprises a joining element  10 . The joining element  10  can be formed from an extruded plastics material having good impact and scuff resistance or a metal (such as extruded aluminium). Two panel retaining portions  11  of the joining element  10  are at right angles to each other and separated by strengthening walls  12 . Joining elements can be produced however with retaining portions at other desired angles, for example 180°. Each retaining portion  11  has flexible side walls  13 A,  13 B to enable a panel  14  to be easily inserted therebetween. Adhesive  21  is introduced between the panel  14  and the outer wall  13 A of the joining element  10 . Positioning of the panel  14  into the desired location and orientation is facilitated by stop members  15  on the inside of the retaining portion  11 . 
   A further feature of the invention is the option of adding a hole-reinforcing adapter to the hole  16  in the in-use inner wall of the panel  14 . The hole  16  enables a flat-ended load screw  17  to be passed through a threaded hole  18  in the inner wall  13 B of the retaining element  10 . The adapter would normally have a bore diameter slightly larger than the outer diameter of the fastening screw. As the screw  17  is screwed into the panel  14  therefore, the panel  14  is pushed against the wall  13 A. In order to further secure the panel  14  to the walls  13 A,B, adhesive can be included. 
   A number of barbs  19  can also be included in the inner surface of the inner walls  13 A to provide further grip on a panel  14 . A bond weld  20 , which can take the form of further adhesive or a sealant compound can be included. The bond weld  20  performs a number of functions. Firstly, it provides further bonding between the panel  14  and the wall  13 B. Secondly, it closes any remaining gaps between these two elements and improves the sealing and the appearance of the finished article. 
   The joint which is achieved by the above has advantages over conventional joints. Firstly, from a security point of view, as screw heads are normally on the inside of the finished article, the screws cannot be removed to facilitate access to the article. Secondly, from an aesthetic view point, the appearance of the article is improved. Thirdly, with conventional articles of similar construction, the inner face of the wall  13 A may be pulled away from the panel during manufacture, a problem which is obviated by the current invention. Fourthly, the inner wall  13 B remains mechanically coupled to the panel  14 . 
   An alternative embodiment of a coupling means is disclosed in  FIGS. 2 and 3 . The features of the joining element and the panel are substantially as described above in relation to  FIG. 1 . In addition however, the embodiment of  FIG. 2  includes a retention adapter  30  which fits into a correspondingly shaped hole within the panel  14 . The retention adapter  30  has a recess to engage and retain in position a reaction and locking nut  31 . The recess preferably has the same cross-section as the locking nut to improve the grip on and prevent rotation of the locking nut  31  as the screw  32  is tightened. 
   As the screw  32  is tightened, the wall  13 B is put under compression and the panel  14  and the wall  13 B are pushed apart. Furthermore, a load arises which tends to push the panel  14  against the outer wall  13 A. As the screw  32  is tightened further it pushes against an end section  33  of the hole  34 . The end face of the screw reacts onto the end section  33  and causes the locknut to ease out of its recess towards the inner, panel-side face of the wall  13 B, ultimately causing the screw to lock securely against the wall  13 B and preserving the compressing preload force by means of the elastic spring effect of the wall  13 B. The diameter of the closed end of the hole  34  is smaller than that of the screw  32  and undergoes plastic deformation. The deformation results in the plastic flowing into the thread of the screw and provides, in the finished product, anti-vibration pressure. The plastic will act to hold the screw  32  in position and therefore during transportation of an article which includes a fastening as described above, any vibrations such as from a vehicle will not cause the screw to come loose. 
   As with the joint shown in  FIG. 1 , adhesives and bond welds can be applied to improve the strength and appearance of the joint. Barbs and profiling of outer the wall  13 A may also be employed to refine the system. Furthermore, rivets may be used as alternatives to or in addition to a screw-type fastening. 
   The embodiment of the invention shown in  FIGS. 2 and 3 , includes the additional feature that the hole  34  is slightly eccentric. The eccentricity of the hole causes the screw  32  to be guided into position and also to grip and hold the panel more tightly in the required position urging it against stop members  15 . In some circumstances this option is not required and an embodiment utilising a concentric arrangement of hole  34  would suffice. 
   An advantage of the above described invention is that the panels can be easily assembled together. In that sense the individual components can be manufactured and subsequently dispatched to be assembled by relatively unskilled workers. 
   The retention adapter  40  as shown in  FIG. 4  has barbs  41  to prevent the adapter  40  from being lifted out of the hole in the panel  14  prior to the panel being engaged into the joining member. A recess  42  which can accommodate a locking nut having a hexagonal cross-section is shown. 
   In use, when two or more panels are to be joined together, a panel according to the above invention is taken. A retention adapter, if not already present is inserted into a corresponding hole within the panel and a locking nut located in the aperture provided in the adapter. The panel is brought in to correct alignment with a joining member, between two retaining walls of said joining member. An adhesive can be applied at this stage between the wall of the panel and the inner face of the retaining wall  13 A of the joining member. 
   Alignment is achieved by locating the edge of the panel against the stop members in the joining member and ensuring that a clearance hole in the joining member is over the locking nut opening. A screw is then screwed in through the joining member and into the retaining member. The screw may be profiled with a reduced-diameter lead-in section so as to help guide it into the appropriate female section. As the screw is tightened, the outer wall and the panel are brought together. Once the screw has been tightened, the joint produced can be sealed and further strengthened on the inner wall  13 B of the joining member using a bond weld. 
   A further aspect of the present invention is shown in  FIG. 5  in which a panel  50  is held into position with a joining element  51  by means of a push or snap-fit mechanism. The push or snap-fit biases the panel  50  towards the inside face of the outer wall  54 A of the joining member  51 . In order to effect the joint, panel  50  has a raised ridge  52  running along its length (see  FIG. 6 ). The ridge  52  engages a recess  53  in the joining element  51  and co-operates to retain the panel  50  rigidly in position. The joining element  51  shown in  FIG. 5  is substantially similar to that shown in  FIG. 1 , with a primary difference being the lack of a hole through which a screw can pass. 
   In order to provide an even stronger bond, the joining element  51  can be provided with non-parallel sides  54 A,  54 B which are inclined towards one another. For example, whist the outer wall  54 A is at right angles to the strut  55 , the inner wall  54 B is inclined at an angle towards the outer wall  54 A typically an angle of up to 5° has been shown to give a good joint, although angles of from 0.7° to 2° have been found to be most effective. 
   Furthermore, the joining element  51  includes a chamfered edge  56 . The chamfered edge  56  facilitates insertion of a panel  50  into the joining element  51  during the assembly process. 
   The push-fit mechanism can be used in conjunction with the features relating to the adapter/screw mechanism shown in  FIGS. 1 to 4 . 
   Alternatives to a single ridge along the length of the panel, a number of other features can be used. For example, a castellated projection or even a series of staples whose heads protrude from the panel could also be used. Furthermore, any ridge or projection does not have to run parallel to the edge but could also be disposed at other angles with a proviso that the panel joining member has a corresponding recess to engage ridge or projection. 
   The panels as used herein are primarily sheet materials which are locally planar along their edge, enabling them to be joined to other panels. The panels can be constructed from materials formed by the pressure bonding of a plurality of layers and having rigid outer layer and a lightweight inner layer. The outer layer can be formed from a number of layers or skins, for example plywood, MDF or plastics material. The inner layer can be formed from a lightweight material such as a plastic or aluminium and have a honeycomb structure which can impart strength and rigidity whilst reducing weight. Alternatively, the sheet material can be a single layer of wood, plastic or metal. 
   An alternative aspect of the invention is shown in  FIG. 6 . The features shown here are suitable for use in cases for transporting goods and materials. The joining element  71  is similar to that shown in  FIG. 5 , and in this instance is to form a corner of the base of a suitcase or packing case. The wall  72  of the case is planar having a thickness of approximately 1 mm. It is therefore far thinner and lighter than other wall panels described above in relation to the other figures. The case produced is therefore lighter and has a greater internal volume. In order to retain the wall  72  in position a retaining element  73  is inserted between the wall  72  and the internal edge  74  of the joining element  71 . The retaining element  73  engages the internal edge  74  by means of a push-fit mechanism, a ridge  75  on the retaining element  73  engaging the recess  76  of the joining element  71 . An adhesive  77  is added to further secure the components together. The joint formed can be further secured by passing a securing element such as a screw or rivet through the internal wall  78  into the retaining element  73 . In the particular example shown here, a foot  79  is secured to the joining element  71  to provide protection for the case when the case rests on the floor. 
   It can be noted that elements, (as shown in  FIG. 7 ) smaller than a normal panel but having the same configuration can be slotted, by means of the projections  80  into larger panel elements to provide the larger panel elements with the projections required for push or snap-fit assembly. 
   It will of course be understood that the invention is not limited to the specific details described herein, which are given by way of example only, and that various modifications and alterations are possible within the scope of the invention.