Handrail

Abstract

A rail attachment system comprising a first and second rail, 10a and 10b, with internal threaded holes 13 and an elongate connecting member, e.g. threaded bar or rod 40, with two threaded portions, 41

Description

Background of the Invention The invention relates to handrail systems and in particular a system for mounting and attaching rail sections together. Hand rails are often installed in spaces where additional support may be helpful for users, such as on stairs. Various ways exist for providing such handrails but they typically include rail sections supported periodically by brackets which may be mounted on a wall, post or other suitable structure such as a staircase. Installation of such rails can be complex as the rails must often be precisely sized to fit specific lengths where they are to be installed. For example on a staircase, the rail might be mounted on a wall and extend from the bottom of a staircase running parallel to the stairs, then turn a corner as the staircase reaches a landing, where the staircase goes around and back on itself. The rail will typically turn to be horizontal, parallel to the floor of the landing, and then extend along the wall of the landing before turning again to follow the next flight of stairs up. It will therefore be appreciated that in order to follow the desired profile, the lengths of the rails need to be accurately defined with suitable interconnecting pieces, such as wall mounting brackets or parts to accommodate the changes in angles of the rails and so on. Similarly, the mounting brackets for supporting the rails will need to be provided at defined positions to allow attachment to the rails at the correct position. The rails may have pre-cut mounting points to align with the mounts. The mounts also need to be attached to the wall or other supporting element such as a post or other structure. Currently available rail systems tend to use a saddle bracket system. These work by using lengths of rail that are sat on top of a wall mounting bracket with a saddle portion for supporting the rail. The rail is then connected to the saddle using a pair of screws which pass through the saddle and screw into threaded holes in the rail. In some off-the-shelf systems, the rails are sold in various lengths with pre-drilled holes to receive the screws to attach the rails to the saddles. This is rather limiting as the positions of the brackets may not be suitable for the application and so may require modification on site. Another common system uses lengths of rail (generally as long as possible) which are supported on top of a saddle connected to the wall bracket. Again, the saddle has two holes for fixings but the rails do not have predefined holes for connecting to the bracket. Instead, the brackets are positioned where they are required. The rails are temporarily placed in position and the rail is then marked for drilling and tapping so the saddle and the rail can then be fixed to each other. Whilst this arrangement allows greater flexibility in where the mounting brackets can be positioned, there are a number of drawbacks with this type of system. Drilling and tapping holes on site can be difficult to do. Stock rail is often sold in long lengths (sometimes as much as 6 metres in length) which are more difficult and expensive to pack and transport. They are also awkward to move around on site, particularly through corridors and stairways etc. as well as when manipulating them into position and getting them ready for installation. The rails are typically cut to length on site with angle sections and bends then glued into the ends of open tube. These are usually attached to each other using adhesive, which is very expensive and can be messy to use on site, often leaving joints which can be unsightly with a lot of radial mismatch. This also tends to make them difficult to disassemble and refurbish. The requirements of the rails mean that mounting and installation of the rails often requires high accuracy and may require an initial measurement operation to utilise rails precut to precise lengths off site. They may be cut to size on site during installation although as noted above that is often challenging in typical installation spaces. The rails then need to be arranged on the mounts and the mounts attached to the walls. This might involve manipulating a first rail, the mount to which it is attached and possibly a second rail which is to be attached to the mount where rails are joined together. This is common where the mount acts as an interface between consecutive rails. Manipulating two rails and a mount whilst trying to attach the mount to a wall makes installation challenging and may require several people to hold various pieces. Various other methods have been proposed to try to aid the installation process and the attachment of the rails to each other and to the mounts, to try to reduce the complexity and workload associated with manufacture and installation. Arrangements such as those shown in JP2001 / 123628; JPH11 -117488; JP2001-317174; and JP2004 / 232216 utilise a termination arrangement on each end of the respective rails to be joined. The terminations are then engaged with each other, often with a portion of a mount in between and a screw or other fastener inserted to retain the terminations in engagement with each other and the mount. This allows the rails to be joined and a mount attached which can then be used to mount the rails on a wall etc. However, these arrangements typically involve complex parts which need to be mounted onto the ends of the rails and then attached to them, often using multiple screws to screw the mounting onto the end of the rail. They may also suffer the same issue with needing to support both rails and the bracket simultaneously whilst installing. Summary of the Invention Therefore according to the present invention there is provided a rail attachment system, comprising: a first rail with an internally threaded first hole at one end; a second rail with an internally threaded second hole at one end; an elongate connecting member having a first threaded portion and a second threaded portion arranged at opposite ends, the first threaded portion having a first diameter corresponding to the internal diameter of the first hole and the second threaded portion having a second diameter corresponding to the internal diameter of the second hole; and an intermediate element having a passage passing therethrough, wherein the passage is sized to allow the first threaded portion of the connecting member to be inserted into an end of the passage to protrude from the other end of the passage to allow it to be screwed into the first hole, whilst at least part of the second threaded portion projects from the intermediate element to be received into the second hole, to allow the second rail to be screwed onto the second threaded portion. This arrangement provides a system which allows two rails to be easily connected to each other and to an intermediate member without needing several people to temporarily support the parts during construction and allowing the use of simple parts which can be pre-constructed off-site. It further allows the rails to be attached to each other by hand or using relatively simple tools to turn the connecting member. Complex connecting parts between the rails and other interfacing elements are avoided, simplifying manufacture of the rails and intermediate element. The screwed connection means that the rails can be supported at one end temporarily prior to and during installation avoiding the need for a separate installer to hold parts. Optionally, at least part of the passage is internally threaded with a diameter corresponding to the first threaded portion. This allows the intermediate member to be screwed into the intermediate member and then into the end of the rail. This means the connecting member can have a very simple shape such as a simple threaded rod. Alternatively, the internal dimension of the passage is large enough to allow the first threaded portion to pass freely through the passage and the connecting member includes a central portion arranged between the first threaded portion and the second threaded portion. This central portion may have a dimension larger than a first passage section of the passage. This means that the connecting member can be inserted into the intermediate member until the central portion meets the edge of the smaller first passage, preventing the connecting member passing further into the intermediate member. Then as the first threaded portion is screwed into the first rail, the first rail is pulled toward the intermediate member until they in turn engage each other and further tightening is prevented and the intermediate member and rail are held together. The passage preferably includes a second passage section having a dimension larger than the central portion. This allows the central portion to be received within the second passage section. This means the central portion can be completely contained within the intermediate member with only at least part of the second threaded portion protruding from it. This avoids the central portion interfering with the second rail being screwed fully up to the intermediate member preventing the end faces engaging, without having some provision for accommodating the central portion in between, such as by providing a recess on the end face of the second rail. The length of the second passage section is preferably equal to or greater than the length of the central portion. This allows the central portion to be fully accommodated within the second passage section when the connecting member is inserted into the intermediate member. The passage preferably may have a uniform diameter along the length of the passage. This provides a simpler construction. The connecting member is preferably rotated to screw the first threaded portion into the first hole. As this happens, the central portion engages the intermediate element to pull it into engagement with the end of the first rail. The second threaded portion preferably protrudes from the intermediate element and is screwable into the internally threaded second hole on the second rail to pull the second rail into engagement with said intermediate element. The end face of the rail is preferably abutted against the end of the intermediate element. The first diameter is preferably the same as the second diameter. This simplifies manufacture but also allows the intermediate element to be reversible and for the rails to have the same sized holes on each end. The connecting member may include a tool engagement portion, such as a recess, on the end of the connecting member adjacent to the second threaded portion. This allows engagement of a tool to aid screwing the connecting member into the first hole. The recess may be a hexagonal recess extending into the connecting member from at least one end for use with a hexagonal tool. Other shaped or formed engagement surfaces or recesses may be provided to allow a tool to be engaged with the connecting member to allow it to be driven in rotation. The present invention also provides a method for attaching a first rail and a second rail, comprising: providing a first rail with an internally threaded first hole at one end; placing an intermediate element having a passage passing therethrough adjacent to one end of said first rail; inserting an elongate connecting member having a first threaded portion and a second threaded portion arranged at opposite ends, the first threaded portion having a first diameter corresponding to the internal diameter of the first hole, the first diameter being less than said passage to allow said first threaded portion to be inserted into said passage to protrude from the other end; screwing said first threaded portion into said first hole, to bring an end face of the first rail into engagement with a first end face of the intermediate element; inserting the second threaded portion into an internally threaded second hole at one end of a second rail, the second hole having an internal diameter corresponding to the diameter of the second threaded portion; and rotating said second rail to screw it onto said second threaded portion and bring an end face of the second rail into engagement with an end face of said intermediate element to retain said intermediate element between the ends of said first and second rails. The connecting member may be inserted into the passage, with the first threaded portion having a dimension smaller than a first passage section of the passage, it then passes freely through the passage until a central portion of the connecting member, between the first threaded portion and the second threaded portion and having a dimension larger than first passage section, engages the internal edge of a first passage section. Brief Description of the Drawings The present invention will now be described in detail by reference to the attached drawings in which: Figure 1 shows a perspective view of the components of the rail system; Figure 2 shows an exploded view of the arrangement of Figure 1; Figure 3 shows a transparent view of one end of a first rail; Figure 4 shows 1 transparent view of a short second rail; Figure 5 shows a transparent connecting member; Figure 6 shows a mounting bracket; Figure 7 shows a perspective view of the components of the rail system partially assembled; Figure 8 shows a cutaway cross section of an assembled rail system; Figure 9 shows a transparent version of the cutaway cross section of Figure 8; Figure 10 shows a transparent version of the view of Figure 1; Figure 11 shows a transparent version of the view of Figure 2; Figure 12 shows an image of the exploded rail system; Figures 13a-13f show various alternative arrangements for the connecting member; Figure 14 shows an exploded view of a right angle corner system; Figure 15 shows an exploded view of an angled corner system; and Figure 16 shows an exploded view of a wall return system. Detailed Description Figure 1 shows an example of a rail system prior to assembly of the components. This shows the end of a first rail 10a which would in use extend from a previous section of the rail system. A second rail 10b is also shown to the right of Figure 1. This rail 10b is shown with the opposite end visible. This would represent a very short rail which is unlikely to be used in practice except for special situations where a very short piece is necessary but is shown here for simplicity. In practice longer rails are likely to be used to bridge between mounting brackets at spaced intervals. The rails 10, 10a, 10b are typically similar although they may be of different lengths and may have different ends in some cases according to how they are used. The first and second rails 10a, 10b have different labels in this example but are similar and both would typically be around 1m in length, except at ends, corners, changes of angle in the rail where they might be shorter to suit the layout of the rail. This provides a practical spacing between mounting brackets and allows a highly modular system to be provided to aid installation and delivery of stock to a site. This length also makes manipulation of the rails easier for an installer working alone. In practice, different lengths may be used to match the installation requirements to accommodate rails which are not of exact integer metres in length and also for short sections such as where the rail turns around consecutive corners. The rails are provided with inserts 12, 22, 26 at each end. As can be seen from Figures 3 and 4, the inserts 12, 22, 26 are inserted into each end of respective hollow tubes 11, 21 forming the bodies of the first and second rails 10a, 10b. In this example, the tubes are made of a metal such as stainless steel. The inserts are retained in the respective tube, using an adhesive or other retaining means such as a friction fit or a mechanical retainer such as a screw. The inserts are typically installed at the manufacturing stage prior to delivery to the installer so that the rails are provided as complete units including the inserts. The inserts have a central threaded bore 13 and may also include a pair of recesses 14, 28 used for tightening the assembly, as explained in more detail below. Figure 6 shows a mounting bracket 30. This is used for mounting the rail assembly to a wall or other supporting structure such as a post. The mounting bracket 30 has a wall mounting piece 39 which is attached to an intermediate element 31 by a stem 38 extending between them. The intermediate element 31 is arranged between the ends of the rails 10a, 10b in use, to facilitate connection of the rails to each other and the rails to the mounting point on the wall etc. The intermediate element 31 includes a central through bore with three separate sections. The first and second outer sections 32, 33 of the through bore are arranged to extend inward from the outer end faces of the intermediate member. The inner third section 34 of the through bore is arranged between the two outer sections 32, 33. In the example shown in Figure 6, the third section 34, has a smaller diameter then the two outer sections which have similar diameters to each other. This results in an annular wall or flange where the first outer section 32 and the inner third section 34 meet. A similar wall is also formed where the second outer section 33 and the inner third section 34 meet. Figure 5 shows a transparent view of a connecting member 40. The connecting member is a generally elongate member which is provided with a first threaded portion 41 at one end and a second threaded portion 42 on the other end. A flanged portion 43 is provided between the first and second threaded portions 41, 42. This section has a larger diameter than the threaded portions 41, 42 so that it can engage with the annular end face 35 formed between the first outer section 32 and the inner third section 34. The flanged portion 43 is shown as having a hexagonal shape but it may have other shapes as long as the dimensions are sufficient to prevent it passing through the inner third section 34. The connecting member 40 is provided with a hexagonal recess 44 at one end, used for tightening the connecting member 40. The construction of the rail assembly will now be described. As a typical starting point, the installer will have a first rail 10a arranged in position with one end already mounted or supported (although this is not essential). The intermediate element 31 of the mounting bracket 30 is then brought up to meet the end of the rail 10a so that the end face of the intermediate element abuts the end face of the insert 12, as shown in Figures 7 and 8. The connecting member 40 is then inserted into the central bore of the intermediate element. The first threaded portion 41 of the connecting member 40 passes through the first outer section 32 of the through bore, on through the inner third section 34 and through the second outer section 33 of the through bore until it emerges from the opposite side of the intermediate element. It then meets the threaded bore 13 of the insert 12. The connecting member is then rotated to screw it into the threaded bore 13. It will be apparent that the threaded bore and first threaded portion 41 of the connecting member have corresponding dimensions. As the connecting member is moved through the through bore in the mounting bracket and screwed further into the bore 13, the flanged portion 43 moves into the first outer section 32 of the through bore. The dimension of the first outer section 32 is large enough to receive the flanged portion 43. As the connecting member continues to be screwed into the bore 13, the flanged portion 43 is pulled into engagement against the annular end face 35 of the edge of the inner third section 34. This will force the intermediate element 31 towards the end face of the insert 12 of rail 10a. As they engage, the intermediate element 31 is held between the connecting member 40 and the rail 10a. The initial screwing of the connecting member 40 into the insert 12 can be done by hand using the protruding second threaded portion 42. Further tightening may be facilitated using the hexagonal recess 44. For example, a hexagonal “Allen” key can be inserted into the recess 44 to facilitate further tightening of the connecting member. Once tightened, the intermediate element and the rest of the bracket 30 will then be firmly held in engagement with the rail 10a. Prior to final tightening of the connecting member 40, the intermediate element 31 can be freely rotated relative to the connecting member and the rail 10a. This allows the intermediate element 31 to be adjusted to align the bracket and the wall mounting piece 39 with the wall it is to be mounted on. At this stage, the installer can mark the mounting points and / or proceed to drill and mount the bracket on the wall. Once the wall mount has been correctly positioned, final tightening of the connecting member 40 can be done using the hexagonal key, as mentioned above. Once this stage is completed, the second threaded portion 42 will be left protruding from first outer section 32 of the through bore. A second rail 10b can then be brought up to the second threaded portion 42. The second rail has a similar insert 22 to the insert 12 in the first rail at its end. A threaded bore 23 is provided (see Figure 4), similar to the bore 13 in the insert 12 in the first rail. The bore 23 is then aligned with the end of the second threaded portion 42 and the first rail can be rotated so that the second threaded portion 42 is received into the bore 23. The rail is rotated until the end face of the insert 22 abuts against the end face of the intermediate element 31 and the rail tightens against it. Rotation of the rail is relatively easily done by hand. Rails are typically of the order of around 1 m in length and so can be easily manipulated by hand by a lone installer without needing assistance. With the mounting bracket already in position, from the previous step, it is easy to simply screw the next rail onto the mounting bracket. As noted above, the short rail 10b shown in the figures is meant to be schematic and would typically be longer than that shown although, as noted above, short rails may be used in some instances, where the installation configuration requires it. Even with longer rails, the simple bore and threaded portion 42 makes installation easy and will hold the rail in position ready for the mounting bracket to be mounted on the other end. Although a fairly tight fit can be achieved by hand, final additional tightening can be done using the tightening holes 28 on the far end of the rail. A tool like a pin spanner has its pins inserted into the holes 28 to allow the rail to be rotated and further screwed onto the threaded portion 42.. Figure 8 shows a cutaway view of the constructed rail joint. The intermediate element 31 is visible between the ends of the rails 10a, 10b with the connecting member 40 screwed into the bore 13. The flanged portion 43 is engaged against the annular end face 35 of the inner third section 34 to pull the intermediate element 31 against the end of the rail insert 12. The rail insert 22 is screwed on to the second threaded portion 42 to pull it against the end face of the intermediate element 31. Once a section of rail is secured between two brackets it cannot become loose because any attempt to unscrew the rail by unscrewing it from one bracket would simultaneously be tightening the rail against the other bracket. As this would already be tightened, this would make any further tightening very difficult preventing any significant movement. This provides the advantage that thread lock or adhesive is not required during installation to prevent subsequent loosening of the rails due to inadvertent or deliberate rotation after installation. In the example above, the inserts 12, 22, 26 are retained within a tubular rail 11, 21. However, other arrangements may be provided. For example, wooden rails may be used with the inserts inserted into a recess formed in the ends of the solid wooden rail. Alternatively, the inserts could act as rail ends rather than being inserted into the rail end. These would be attached to the end face of the wooden rail. These may be screwed onto the end of the rail body, for example using the holes 14, 28. Other arrangements are envisaged where the inserts may be a fully integrated part of the rail, which may be solid. The holes 14, 28 may be omitted and other means of tightening may be used or hand tightening alone may be sufficient. The precise arrangement of the connecting member and the bores through the intermediate element may be modified whilst still providing the ability to clamp the intermediate element against the first rail and allow the second rail to be screwed onto it. For example, the precise position of the inner third section 42 of through bore does not need to be centrally positioned. Other possible arrangements are shown schematically in Figures 13b-13f as alternatives to the arrangement described above, as shown in Figure 13a. The first outer section 32 of the through bore may be dispensed with completely and the annular end face 35 may be flush with the outer end face of the intermediate element 31 (see Figure 13e). This may require a suitable recess on the rail end to accommodate the flanged portion 43 of the connecting member which would be proud of the end surface of the intermediate member. The dimensions of the threads on the first and second threaded portions 41,42 are shown as being the same which provides for flexibility as the dimension of the bores 13, 27 can be the same. However this is not essential and the dimension of the first and second threaded portions can be different. For example, the dimension of the second threaded portion 42 may be larger than the first threaded portion 41, e.g. Figures 13b, 13d, 13f. The second threaded portion 42 and the inner third portion 34 may be integrated into a single section. In other words, the connecting member may be formed of two portions of different dimensions with a stepped portion between them to provide the face to engage with the end face 35. In the arrangement shown in Figures 1 to 12, 13a, 13c and 13e, the flanged portion 43 is integral with the rest of the connecting member 41. However, it may be provided as a separate internally threaded nut which is screwed onto an otherwise simple threaded rod. Similarly, the arrangements in Figures 13b, 13d, and 13f show the connecting member as a single integral piece with only two parts, having different diameter. This may also be formed in two parts with, for example, the larger diameter section having an internal threaded portion for receiving the externally threaded end of part of the narrower diameter portion. With this two part arrangement, the threaded rod can be passed through the through bore in the bracket and screwed into the through bore 13 in the first rail 10a. The flanged portion 43 or nut forming the flanged portion 43 can then be screwed onto the threaded rod to tighten the bracket onto the first rail. Once tightened, the arrangement might appear like those shown in Figures 13e and 13f. However the other arrangements would also be applicable (similar to those shown in Figures 13a-d) although this would require a larger annular space within the bracket to allow a socket to be received into it to be able to reach and tighten the recessed nut. In the arrangements described above, rails can be connected to each other via an intermediate element, which may part of a mounting bracket although it may simply be an inter-rail connection. This works for connecting sequential sections of rail in a linear fashion. However, as noted above, the rails are often required to change direction to follow changes in the floor below and to allow the rail to pass around corners. Figure 14 shows an arrangement which allows a rail system to traverse a corner (either an internal or external corner). In the arrangement shown in Figure 14, the wall is shown schematically behind the rail system, in an arrangement for an internal corner but the wall could have been shown in front of the rail system where the rail is passing around a convex external corner. The arrangement uses similar rails 10c, 10d to the rails 10a, 10b shown above with tubular sections 11, 21 and inserts 12, 22, 26. In this example, the rail 10c might be positioned initially by attaching it to the bracket 30. A corner fixing 61 is then screwed into the end of the rail. The corner fixing 61 has a threaded portion 61 a to be received in the internally threaded hole in the insert on the end of the rail 10c. The corner fixing 61 has a separate boss portion 61b extending from the threaded portion 61a. After the threaded portion 61a is screwed into the insert, the boss portion 61b is left protruding from the end of the rail. A corner piece 60 is then placed onto the protruding boss 61b. The corner piece 60 has a generally cylindrical shape with a flat portion forming an engagement face 65 formed at a right angle to the axis of the cylindrical portion. Essentially, the corner piece 60 appears as if a cylindrical cut has been made at right angles to the cylindrical body, approximately half way through the diameter of the corner piece. The engagement face 65 has a central hole 64 extending into the corner piece 60 for receiving the boss 61b. The corner piece 60 is provided with a flat end face 67 at the end of the cylindrical section. The end face 67 is provided with a protruding threaded rail connector 62. The rail connector 62 in this arrangement is screwed into the corner piece 60 but may be formed integrally with it. The corner piece 60 is also provided with an internally threaded locking hole 66 which extends from the end face 67 into the corner piece 60 to open out into the central hole 64. In use, the corner piece 60 is brought up to the end of the rail 10c and the protruding boss 61b is guided into the central hole 64. Once fully inserted, the end of the rail will be flush with the engagement face 65. The boss 61b extends into the central hole 64 so that the edge of the boss is aligned with the locking hole 66. A grub screw 63 is then inserted into the locking hole 66 and screwed in until it engages the boss 61b and is then tightened to hold the corner piece in engagement with the rail 10c. As shown in Figure 14, the boss 61b can be provided with a flange on the end, to prevent the boss slipping out once the grub screw 63 has been tightened. The boss may have other arrangements such as an angled circumferential groove to receive the end of the grub screw which might have a matching pointed profile to accurate align the two and aid with pulling the boss into the hole 64 and the end face of the rail 10c against the engagement face 65. Finally, the second rail 10d forming the next portion of the railing is brought up to the corner piece and screwed onto the protruding rail connector 62 in a similar manner to that described above for rail 10b. Once fully tightened up to the end face 67, the corner piece is completed and the rest of the railing can be installed. The corner piece 60 provides a convenient way of allowing a turn in the direction of the rail being installed. The arrangement shows a rail turning through a right angle due to the engagement face 65 being perpendicular to the end face 67 but the configuration of the corner piece may be adjusted to provide different angles. Figure 15 shows a different arrangement, used for forming an angled bend at an angle which is not a right angle. In this example an angle of 45 degrees is provided although again, this can be selected by adjusting the geometry of the main body 70 of the elbow piece shown in Figure 15. The elbow piece includes two main parts, a main body 70 and rail connector 72 which acts as an interface between the main body and the rail. The main body 70 includes a generally cylindrical body with a cylindrical cut (along an axis 79 offset from the axis 78 of the main body) made into it, to form a cylindrical recess with a flat engagement face 73 at the base of the recess. The engagement face is oriented such that an axis 79 perpendicular to the face is arranged at an angle to the main axis 78 of the cylindrical body. The angle represents the change in angle (in this example 45°) between the axis 78 of the rail at one side of the elbow piece and the axis 79 of the next rail at the other side of the elbow piece. The engagement face 73 includes a fastener recess 75 extending along the axis 78 of the main body and out of the end face of the main body. The engagement face 73 also includes additional internally threaded holes 77 for receiving fasteners 74. The rail connector 72 provides an interface between the main body 70 and the next rail 10d. It has a generally cylindrical body with a flat end face for engaging the engagement face 73. It includes at least one, in this case two through holes 721 for receiving fasteners 74. At the opposite end to the flat end face, a threaded stub 76 is provided. As a railing is constructed, it may be desirable to have a change in the direction of less than a right angle, such as 45°. For example, where a railing extends up a staircase, it may be parallel to the rising staircase but at the top, the rail may need to change direction to be parallel with a landing area at the top of the stairs, requiring a change in angle. As shown in Figure 15, a rail 10c is extending in a first direction along an axis 78 but needs to turn to follow a second direction along axis 79. The rail 10c can be initially installed to the bracket 30 shown in the bottom left of Figure 15, as described above. At the end of the rail 10c, a main body 70 is attached by bringing it into engagement with the end face of the rail. A fastener 71 is then inserted into the fastener recess 75 which extends through the main body 70. The fastener is threaded and once it has been passed through the main body, it can be screwed into the rail 10c. The threaded portion is similar that on the first threaded portion of the connecting member 40 and so the same rails 10 can be used without modification. The fastener recess 75 includes an internal change in diameter providing an edge (not shown) for the wider head of the fastener to engage as it is tightened, to pull the main body against the end of the rail 10c. The fastener may include a shaped recess such as the hexagonal one shown in Figure 15, to allow a tool to be inserted, to aid tightening. Once correctly in position, so that the engagement face 73 is oriented along the desired axis 79, it can be fully tightened, to retain the main body 70 in position. The rail connector 72 is then brought up to the engagement face 73 to be received into the (at least partial) circular recess on the main body. The through holes 721 are then aligned with the threaded holes 77 in the main body and fasteners 74 inserted to tighten the rail connector 72 onto the main body. Once tightened, the second rail 10d can then be screwed onto the threaded stub 76 in the usual way, as described above. The threaded stub is again arranged to have a diameter corresponding to the second threaded portion of the connecting member so that the same rails can be used. The rail can then be continued as before by adding brackets 30 etc. At the ends of a series of rails, it may be desirable to terminate the end of the rail in different ways. In some case, a simple end cap may be used but in other cases, it may be desirable to have a return, i.e. where the end of the rail continues with a right angle bend towards an adjacent wall or other supporting structure. This can be done using a right angled section like that in Figure 14 but the relatively short distance from the rail to the adjacent wall means that a specific return section may be preferable, such as those shown in Figure 16. Figure 16 shows schematically a rail system, with representative short rail sections 10 arranged to represent a run of rail sections but in this case returns 80 are provided on each of the end rails. The return piece 80 has a generally circular body (although this is not necessary and other shapes are possible). The return piece has an end face at the one end of the circular body, to be aligned against the adjacent wall (or similar structure) or some interface such as a wall mounting plate. The rail end of the return piece 80 has a circular recess 84 formed into it, the recess being oriented along an axis parallel to the axis of the rail 10 and perpendicular with the circular body part of the return piece. A face 85 is formed at the base of the circular recess 84 and is provided with a through hole 86 extending along the axis of the rail. To install the return, the return piece 80 is brought up to the end of the rail, so that the face 85 is adjacent to the rail end. The return piece 80 is aligned so that its other end is aligned adjacent to the wall. A fastener 81 is then inserted into the recess 86 and screwed into the threaded bore 13 in the end of the rail. The fastener 81 is then tightened to pull the return piece 80 against the end of the rail. An end cap 82 may then be slotted into the end of the through hole 86 to hide the fastener 81. The wall end of the return piece 80 may be simply held in place against the wall supported by the rail or a wall mounting plate may be provided to provide additional support. The end of the return piece 80 is then attached to or supported by the wall mounting piece. Other modifications to the examples above may be made. The hexagonal recess 44 shown at one end of the connecting member 21 may be provided at both ends for simplicity. It may also be provided with different shapes, such as a square profile or may have a cross-shaped head for receiving a conventional cross-head screwdriver. Other means of tightening may be used. For example, the external thread may include flats to allow a spanner to be used to tighten the connecting member. The recess may be dispensed with altogether. For example, after initial hand tightening, final tightening could then be achieved by tightening the second rail 10b. As the second rail is tightened onto the connecting member, any slack in the connection between the connecting member and the first rail will be taken up. In the example described above, the intermediate element 31 includes the inner third portion 34 which is essentially a narrower portion of the through bore or a circular flange in the middle of the through bore. Referring to figure 8, it will be apparent that the widened part of the through bore, outer second portion 33 is not essential to the operation of the system. This portion simply needs to be sufficiently large to allow the first threaded portion 41 to pass through. In that way, inner third portion 34 and the outer second portion 33 could be one continuous part with a uniform cross-section (see Figure 13c). However, having the outer second portion 33 with a larger diameter allows the system to be used in either direction. In other words, the mounting bracket can be connected to a rail on its right hand side (as shown in the figures) first and the connecting member 40 inserted form the left hand side and tightened before a second rail is screwed onto the portion of the connecting member protruding from the right hand side of the intermediate element 31. In the extreme case, the connecting member could be a simple threaded shaft which is screwed into the first rail in the same way but without the flanged portion 43. With this arrangement, the shaft can either pass freely through the through bore or the through bore may be provided with an internal; thread corresponding to the threaded connecting member. In the first case, when the connecting member is screwed into the rail, the intermediate member will not be held against the end of the rail. However, once the second rail is screwed on, the two rails will move towards each other and eventually clamp the intermediate member between them. In the second case, where a threaded through bore is used, the first rail is held in contact with the intermediate member as the connecting member is screwed in holding the two parts together, the second rail can then be screwed on to tighten it against the intermediate member.

Claims

1. A rail attachment system, comprising:a first rail with an internally threaded first hole at one end;a second rail with an internally threaded second hole at one end;an elongate connecting member having a first threaded portion and a second threaded portion arranged at opposite ends, the first threaded portion having a first diameter corresponding to the internal diameter of the first hole and the second threaded portion having a second diameter corresponding to the internal diameter of the second hole; andan intermediate element having a passage passing therethrough, wherein the passage is sized to allow the first threaded portion of the connecting member to be inserted into an end of the passage to protrude from the other end of the passage to allow it to be screwed into the first hole, whilst at least part of the second threaded portion projects from the intermediate element to be received into the second hole, to allow the second rail to be screwed onto the second threaded portion.

2. A rail attachment system according to claim 1 wherein at least part of the passage is internally threaded with a diameter corresponding to the first threaded portion.

3. A rail attachment system according to claim 1 wherein:the internal dimension of the passage is large enough to allow the first threaded portion to pass freely through the passage; andthe connecting member includes a central portion arranged between the first threaded portion and the second threaded portion, the central portion having a dimension larger than a first passage section of the passage.

4. A rail attachment system according to claim 3 wherein the passage includes a second passage section having a dimension larger than the central portion for receiving the central portion within it.

5. A rail attachment system according to claim 4 wherein the length of the second passage section is greater than the length of the central portion such that thecentral portion can be accommodated within the second passage section when the connecting member is inserted into the intermediate member.

6. A rail attachment system according to claim 3 wherein the passage has a uniform diameter along the length of the passage.

7. A rail attachment system according to any one of claims 3 to 6, wherein as the connecting member is rotated to screw the first threaded portion into the first hole, the central portion engages the intermediate element to pull it into engagement with said one end of the first rail.

8. A rail attachment system according to any one of claims 3 to 7, wherein said second threaded portion protrudes from the intermediate element and is screwable into the internally threaded second hole on the second rail to pull the second rail into engagement with said intermediate element.

9. A rail attachment system according to any one of the preceding claims wherein the first diameter is the same as the second diameter.

10. A rail attachment system according to any one of the preceding claims wherein the connecting member includes a tool engagement portion on the end of the connecting member adjacent to the second threaded portion.

11. A rail attachment system according to claim 10 wherein the tool engagement portion is a recess extending into the connecting member for receiving a correspondingly shaped tool into said recess.

12. A method for attaching a first rail and a second rail, comprising: providing a first rail with an internally threaded first hole at one end;placing an intermediate element having a passage passing therethrough adjacent to one end of said first rail;inserting an elongate connecting member having a first threaded portion and a second threaded portion arranged at opposite ends, the first threaded portion having a first diameter corresponding to the internal diameter of the first hole, the first diameterbeing less than said passage to allow said first threaded portion to be inserted into said passage to protrude from the other end;screwing said first threaded portion into said first hole, to bring an end face of the first rail into engagement with a first end face of the intermediate element;inserting the second threaded portion into an internally threaded second hole at one end of a second rail, the second hole having an internal diameter corresponding to the diameter of the second threaded portion; androtating said second rail to screw it onto said second threaded portion and bring an end face of the second rail into engagement with an end face of said intermediate element to retain said intermediate element between the ends of said first and second rails.

13. A method according to claim 12 wherein as the connecting member is inserted into the passage, the first threaded portion having a dimension smaller than a first passage section of the passage passes freely through the passage until a central portion of the connecting member, between the first threaded portion and the second threaded portion and having a dimension larger than first passage section, engages the internal edge of a first passage section.

14. A method according to claim 13 wherein the central portion has a dimension smaller than a second passage section and the method includes inserting the central portion the second passage before engaging the internal edge of a first passage section.

15. A method according to claim 14 wherein the length of the second passage section is greater than then length of the central portion and the method includes inserting the central portion completely within the second passage section when the connecting member is inserted into the intermediate member.

16. A method according to claim 13 wherein the passage has a uniform diameter along the length of the passage and the method includes inserting the connecting member into the intermediate member until the central portion engages the external face of the passage.

17. A method according to any one of claims 13 to 16, wherein said screwing includes screwing the intermediate member into said first hole until the intermediate member is tightly held between the rail and the connecting member as the central portion engages the intermediate element to pull it into engagement with the first rail.

18. A method according to any one of claims 13 to 17, further comprising screwing a second rail, having an internally threaded second hole at one end, onto the second threaded portion of the connecting member until one end of the second rail is pulled into engagement with said intermediate element.

19. A method according to any one of claims 12 to 18 wherein the connecting member includes a tool engagement portion on the end of the connecting member adjacent to the second threaded portion and said screwing includes turning the connecting member using a tool engaged with the tool engagement portion.

20. A method according to claim 19 wherein the tool engagement portion is a hexagonal recess extending into the connecting member and said screwing includes inserting said tool into said recess to engage said connecting member.

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