EP3317467A1

EP3317467A1 - Connector for structural building frames

Info

Publication number: EP3317467A1
Application number: EP16726321.9A
Authority: EP
Inventors: Steven LIMB
Original assignee: Saint Gobain Placo SAS
Current assignee: Saint Gobain Placo SAS
Priority date: 2015-07-01
Filing date: 2016-06-01
Publication date: 2018-05-09
Anticipated expiration: 2036-06-01
Also published as: GB201511575D0; EP3317467B1; TW201702464A; MA42288A; WO2017001136A1

Abstract

A connector 1 for connecting together first and second elongate frame members 28, 23 of a stud wall. The first member 28 comprises an axially extending channel and the second member 23 has a channelled longitudinally extending profiled surface 27. The connector has a first elongate end 20 adapted to slidably fit into the channel at one end of the first frame member 28 and a second end 21 having a ribbed distal end face 22 which comprises a profile which is complementary to the channelled surface of the second frame member. In use, the distal end face of the connector 1 is butted up against and comes into complementary engagement with the channelled surface of the second frame member 23. A screw 30 holds the connector 1 against the profiled surface of the second member 23 to form an L-shaped structure which forms two sides of the desired frame.

Description

CONNECTOR FOR STRUCTURAL BUILDING FRAMES

The present invention relates to structural building elements and more particularly to a connector for joining elongate members such as wall studs and frames members and a frame. In the frame of stud walls, horizontal channels are fixed to a ceiling and a floor, and vertical studs of profiled metal are urged into the channels and fixed in place. Where required, horizontal noggins of profiled metal may be provided between the studs to lend rigidity to the resulting structure. Boards are then fixed to the frame structure, binding it together and forming a wall surface. This conventional frame methodology suffers from a number of disadvantages, including the requirement to use different metal profiles and/or joins for each of the horizontal channels, vertical studs and horizontal noggins. Yet further structures may be required in order to build frames around doorways, and provide fixing points for patresses for electrical sockets and the like. In order to build the frame structure, the frame members have to be cut with a high degree of accuracy and then screwed or otherwise fixed together. This is both difficult and time consuming.

Our co-pending International Patent Application PCT/EP2014/079322 discloses a solution to these problems in the form of a connector which can be pushed axially into one end of a first channel-section frame member, such that an end portion of the connector projects axially from the frame member. The projecting end is provided with transversely extending slots on at least one pair of opposite side faces thereof. In use, the projecting end is inserted into the open channel of a second frame member, which extends at 90 degrees or obliquely to the first. The first frame member is then rotated about its longitudinal axis to cause the slots to embrace respective inwardly directed lips on the mouth of the channel of the second frame member. In this manner no screw or other fixings are required. Any intolerances in the length of the first frame member can be offset by moving the connector axially with respect to the first frame member. In this manner a low degree of cutting accuracy is required.

Frame members of the above type are generally formed of a thin metal and are of insufficient strength to support a door casing. The current practice when forming openings for doors often involves using a double-thickness of metal and sometimes also a timber insert. Hence more components are required and many more steps are involved in the measuring, cutting, folding, assembly and fixing of the members.

With the foregoing in mind and in accordance with the present invention as seen form a first aspect, we have now devised a connector for connecting together first and second elongate frame members, at least the first member comprising a hollow which extends axially along the member, at least the second member having a ribbed longitudinally extending profiled surface, the connector comprising:

a first elongate end portion adapted to slidably fit into the hollow at one end of the first frame member; and

a second end portion having a distal end face which lies perpendicular to the longitudinal axis of the first end portion and which comprises a profile which is complementary to the profiled surface of the second frame member; and

a fastening arrangement for use in fastening said end face against the profiled surface of the second frame member.

In use, a door frame can be constructed by inserting the first end of the connector into one end of a first frame member and then positioning the second end of the connector against the profiled surface of the second frame member, such that the distal end face of the connector butts up against and comes into complementary engagement with the profiled surface of the second frame member. Any intolerances in the length of the first frame member can be offset by moving the connector axially with respect to the first frame member. The end face of the connector is then fastened against the profiled surface of the second member to form an L-shaped structure which forms two sides of the desired frame.

The way in which the profiled distal end of the connector engages the profiled surface of the second frame member ensures an accurate alignment of the two frame members and it is almost impossible for the connector to be rotated or misaligned and so provides the benefit of a flat front and rear face to the frame assembly with no projecting overlaps of metal or fixings.

The second frame member may be mounted vertically and may be formed of a metal which is thicker than that used for conventional channel-section frame members. The increased strength is able to withstand the weight of a door without any extra reinforcement. The whole door frame may be formed using such a frame member with a connector of the present invention at each corner. However, conventional frame members (which do not have profiled surface) may be used for one or more other sides of the frame.

A second connector may be inserted into the opposite end of the first frame member to enable the first frame member to be fixed between two frame members. There is a risk that, when a connector has been inserted into one end of the first frame member, the connector may slide into the hollow as another connector is being fitted to its other end. The connector then needs to be pushed back out before it can be used to join two members. Thus, the connector may comprise a stop which prevents the first end of the connector being pushed too far into the first frame member. The stop may be resiliency deflectable to allow the connector to be urged into the first frame member, the stop being arranged to frictionally engage the inner surface of the first frame member to prevent it from sliding.

The distal end face of the connector may comprise a plurality of ribs for engaging with corresponding channels in the longitudinally extending profiled surface of the second member.

The fastening arrangement may comprise a formation in the distal end face of the connector, through which a screw can be inserted to engage the second frame member. The formation may be an aperture, which may normally be closed but which can be penetrated by a screw.

The connector may also be arranged to connect elongate channel-shaped frame members having an open channel extending along the member and being partially enclosed by a lip extending along the opening, the channel having an opening along one side of the member, the first end portion of the connector being shaped to fit into the channel of a first channel-shaped frame member via one end thereof, the second end portion being shaped to permit its insertion into the channel of a second channel- shaped frame member via the opening therein when the connector is in a first rotational position with respect thereto, the second end portion comprising an engagement structure which is shaped to engage with the lip of the second channel- shaped frame member when the inserted connector is rotated within the channel from the first rotational position into a second rotational position with respect to the second channel-shaped frame member.

The engagement structure may comprise transversely extending slots on at least one pair of opposite side faces of the second end of the connector.

In this manner, the connector can be used to interconnect a variety of different types of frame members such as those used to form door openings or those used to form conventional stud walls.

The connector may be frangible and may comprise a transverse line of weakness extending transverse its longitudinal axis to enable the length of the connector to be shortened, for example in applications where the frame member into which the connector is inserted is short in length.

The line of weakness may extend from an edge of the connector and may comprise a reduced wall thickness, the wall thickness at the edge being thicker to prevent the connector from inadvertently breaking. In use, a user simply has to cut the edges with a cutting implement to allow the connector to be snapped into two.

The first end of the connector may comprise a distal end face which lies obliquely to the longitudinal axis of the first end portion and which comprises transversely extending recesses on at least one pair of opposite side faces of the first end of the connector, said recesses forming an engagement structure for engaging a channel- shaped frame member which lies at an oblique angle of say 32 to 50 degrees to a frame member into which the second end of the connector is inserted.

The connector may comprise a pair of said lines of weakness adjacent respective opposite ends thereof, so as to enable either end of the connector to be shortened.

Preferably the connector is hollow and comprises an open front wall, ribs extending between opposite side walls of the connector. The ribs may extend transversely of the connector to define one or more voids which form pattresses. Also in accordance with the present invention, as seen from the first aspect, there is provided a frame assembly comprising:

a first frame member comprising a hollow which extends axially along the member, a second frame member having a ribbed longitudinally extending profiled external surface; and

a connector, the connector having a first elongate end portion slidably received in the hollow at one end of the first frame member and a projecting second end portion having a distal end face which lies perpendicular to the longitudinal axis of the first end portion and which comprises a profile which is complementary to the profiled surface of the second frame member, the distal end of the connector being butted against the profiled surface of the second frame member, such that the connector comes into complementary engagement with the profiled surface of the second frame, the connector being fixed against the profiled surface of the second frame member by fastening arrangement.

The distal end face of the connector may comprise a plurality of ribs which engage with corresponding channels in the longitudinally extending profiled surface of the second member. The fastening arrangement may comprise a formation in the distal end face of the connector, through which a screw extends to engage the second frame member. The formation may be an aperture, which may normally be closed but which can be penetrated by the screw. The assembly may comprise a third frame member and a second said connector having its first elongate end portion slidably received in the hollow at the opposite end of the first frame member, the third frame member having an open channel extending along the member and being partially enclosed by a lip extending along the opening, the channel having an opening along one side of the member, the second end portion of the second connector being shaped to permit its insertion into the channel of the third frame member via the opening therein when the connector is in a first rotational position with respect thereto, the second end portion of the second connector further comprising an engagement structure which is shaped to engage with the lip of the third channel-shaped frame member when the second connector is rotated within the channel from the first rotational position into a second rotational position with respect to the second channel-shaped frame member.

Also in accordance with the present invention, as seen from a second aspect, there is provided a connector for connecting together first and second elongate frame members, one of the members comprising a hollow which extends axially along the member, the connector comprising:

a first end portion shaped to fit into the hollow of the first frame member via one end of the first frame member; and

a second end portion adapted to engage the second frame member, wherein the connector is frangible and comprises a transverse line of weakness extending transverse its longitudinal axis to enable the length of the connector to be shortened.

The second frame member may have an open channel extending along the member and being partially enclosed by a lip extending along the opening, the second end portion of the connector comprising an engagement structure which is shaped to engage with the lip of the second member when the inserted connector is rotated within the channel of the second member from the first rotational position into a second rotational position with respect to the second member.

The second frame member may have a ribbed longitudinally extending profiled surface, the second end portion of the connector having a distal end face which lies perpendicular to the longitudinal axis of the first end portion and which comprises a profile which is complementary to the profiled surface of the second frame member, the connector further comprising a fastening arrangement for use in fastening said end face against the profiled surface of the second frame member.

An embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which:

Figure 1 is a schematic view of a connector according to the present invention, illustrating how the connector can be used to connect two frame members of a first type; Figure 2 is a plan view of the connector of Figure 1 when fitted to a frame member of a second type;

Figure 3 is a perspective view of the connector of Figure 1 when fitted to the frame member of the second type;

Figures 4A to 4F are perspective views of the connector of Figure 1 ;

Figure 5 is a perspective view of the connector of Figure 1 when fitted to the frame member of the second type;

Figure 6 is a part sectional view of the connector of Figure 1 when fitted to the frame member of the second type; and Figure 7A to 7C are perspective views showing how the connector of Figure 1 can be shortened in length.

Referring to Figure 1 of the drawings, a connector 1 is engaged within a channel 3 of a vertically disposed C-shaped elongate frame member 2. In order to achieve this, the cross section of the connector 1 has external dimensions which substantially match the internal dimensions of the channel 3. Drawing element D in Figure 1 indicates a labelling convention for the various dimensions of the connector 1 . The longest dimension of the connector, extending vertically in Figure 1 is referred as the length L. The remaining dimensions relate to the cross section of the connector 1 , and include the shortest (narrowest) cross sectional dimension W1 , and the longest (widest) cross sectional dimension W2. The end portion of the connector 1 which engages within the channel 3 via its end is referred to as the first end portion 20. The channel 3 extends longitudinally of the C shaped frame member 2 from one end (the end into which the connector 1 is fitted in Figure 1 ) to its other end. The engagement may be a relatively loose slidable engagement, which permits the connector 1 and the C shaped channel 2 to move axially with respect to each other (that is, such that the connector 1 is able to slide into and out of the channel 3 of the member 2), for reasons which will be explained subsequently, or may instead be a relatively tight engagement. The C shaped frame member 2 comprises an opening 4 into the channel 3, which extends along one face (side) of the C shaped member 2. The side of the C shaped member 2 having the opening 4 also comprises longitudinal lips (or rims) 5a and 5b which extend along the side of the opening 4 to retain the connector 1 within the channel 3. At the top of Figure 1 , a horizontally disposed C shaped frame member 6 has a channel 7 extending longitudinally through it. The frame member 6 comprises an opening 8 into the channel 7 which extends along one face (side) of the C shaped member 6. The side of the C shaped member 6 having the opening 8 also comprises lips 9a and 9b which extend along the side of the opening 8. It will be appreciated from Figure 1 that the frame members 2 and 6 are identical and have the same profile (cross section). In one use of the connector 1 , the connector is able to join together two elongate members having the same profile (cross section).

The end portion of the connector 1 which is distal to the first end portion is referred to as the second end portion 21 . The second end portion 21 is provided with a groove 10 which extends (in this embodiment) transversely around all four sides of the connector 1 at a predetermined distance from the (nearest) end of the connector 1.

The second end portion 21 of the connector 1 is intended to engage with the frame member 6. In order to achieve this, the connector 1 is positioned at the entrance 8 to the channel 7 at a desired distance along the length of the frame member 6. The connector 1 is offered up to the channel 7 (directional arrow (A)) in a first rotational position with respect to the frame member 6 and the channel 7. The first rotational position is one in which the widest sides of the connector 1 (dimension w2) are parallel with the edges of the opening 8, or in other words in which the narrowest dimension w1 of the connector 1 is spanning between the edges of the opening 8. In this orientation the connector 1 is able to be inserted through the opening 8 and into the channel 7 of the member 6. It will be noted that the connector 1 as shown in Figure 1 is not in the first rotational position. Once lifted up into the channel 7, the connector 1 is rotated (directional arrow (B)) clockwise with the groove 10 proximate the lips 9a and 9b. As the connector 1 rotates, the lips 9a and 9b will enter into the groove 10. The rotation will continue for 90° until the shorter edge (dimension w1 ) is parallel with the edges of the opening 8. This is the second rotational position of the connector 1 with respect to the member 6. It will be noted that the connector 1 as shown in Figure 1 is in the second rotational position. In the second rotational position, the greatest cross sectional dimension w2 of the connector 1 is such that it extends across the opening 8 to substantially fill the width of the channel 7. It will be noticed that two of the square edges running along the length of the connector 1 are bevelled. These bevelled edges 12 permit the connector 1 to be rotated more easily within the channel 7. Without the bevelled edges, the greatest cross sectional dimension w2 of the connector 1 would have to be smaller in order to permit the connector 1 to rotate from the first rotational position into the second rotational position. In other words, the greatest cross sectional dimension w2 of the connector 1 can be a better fit to the width of the channel 7 when bevelled edges are used on at least two of the edges. As a result, more of the area of the lips 9a and 9b can be accommodated within the groove 10, providing for a stronger engagement between the connector 1 and the member 6. The insert locking mechanism works on the basis of a friction fit between the thin groove 10 and the edge profile of the metal section. Accordingly, bevelling all four edges is less desirable because it reduces the amount of contact between the slot 10 and the lips 9a, 9b.

In engagement with the member 6 using the second end portion 21 of the connector 1 , the sliding engagement of the first end portion 20 of the connector 1 permits the member 2 to slide up and down (directional arrow (C)) with respect to the connector 1 (which is itself locked into place to the member 6). It will be appreciated that the connector 1 can be used to join vertical studs to ceiling and floor (horizontal) channels. The sliding engagement may be able to absorb head deflection where the ceiling channel deforms with respect to the floor channel following installation of the stud. In addition, the slidable engagement reduces the need for the member 2 to be cut accurately to length, because length adjustment can be achieved with the connector 1 . Moreover, the member 2 can be cut shorter than would conventionally be the case, since part of the distance to be spanned is bridged by the connector itself. It will be appreciated that the sliding engagement may instead be with a horizontal member and the twisting engagement with a vertical member. Alternatively, both members may be horizontal in the case where a ceiling or floor structure is being formed, or one or both of the members may even be in an angled orientation such as might be required in the frame of a pitched roof. However, in all these cases it will be appreciated that the connection formed between the two members is a right angle connection. In principle however, the invention might be used to form a non-right angle connection in a case where the first end portion (slide fit) and second end portion (twist fit) are not at either and of a purely linear structure but are instead at either end of a curved or angled structure.

The connector 1 as hereinbefore described is identical to the connector disclosed in our co-pending International Patent Application PCT/EP2014/079322. The frame members 2 and 6 are also of the type widely used in the construction industry to build stud walls and are formed of relatively thin sheet metal.

Referring also to Figures 2 to 6 of the drawings, in accordance with the present invention, the invention further comprises a second type of C shaped frame member 23 having a channel 24 extending longitudinally through it. The frame member 23 is formed of sheet metal, which may be thicker than the sheet metal used for the frame members 2 and 6 of Figure 1 , and comprises an opening 25 into the channel 24 which extends along one face (side) of the C shaped member 23. The side of the C shaped member 23 having the opening 25 also comprises lips 26a and 26b, which extend along the side of the opening 25 and are formed of a double folded thickness of metal.

The frame member 23 further comprises a pair of longitudinally extending channels 27 in its bottom wall which face outwardly. The channels 27 and the folded lips 26a, 26b impart extra strength to the member 23 compared with that of the members 2 and 6 of Figure 1 . This combined with a thicker sheet metal makes the frame member 23 more suitable for use in forming frames around door apertures. The interior of the channel 24 is dimensioned substantially identically to that of the members 2 and 6 of Figure 1 and thus connectors 1 can be engaged with the channel 24 in the same way as that described in Figure 1. When forming a frame around a door for example, the frame member 23 is mounted vertically down one side of the aperture, being the side at which the door will be hung. The frame member 23 is supported by noggins or cross-members (not shown), which are attached using connectors 1 , engaged with the channel 24 in the same way as that described in Figure 1 . Since frame member 23 does not provide a channel facing into the door aperture, it is not possible to attach a horizontal top frame member (or so-called head) using the connector 1 in the same way as Figure 1 .

The second end 21 of the connector 1 comprises a distal end face which lies perpendicular to the longitudinal axis of the first end portion 20 and which comprises a pair of ribs 22 which extend in direction w1 of Figure 1. The transverse sectional ribbed profile of the distal end face substantially conforms with and complements the transverse sectional channelled profile of the external bottom surface of the frame member 23. In use, the connector 1 is slid into one end of a horizontal top frame member 28 in the same way as it is connected to the frame member 2 of Figure 1. The top frame member 28 may be identical to the conventional frame members 2 and 6 of Figure 1 or it may comprise a member identical to the frame member 23 of the present invention. The second end 21 of the connector 1 is then positioned against the profiled surface of the frame member 23, such that the ribbed distal end face of the connector 1 butts up against and comes into complementary engagement with the channelled surface of the frame member 23. Any intolerances in the length of the top frame member 28 can be offset by moving the connector 1 axially with respect to the top frame member 28. The end face of the connector 1 is then fastened against the channelled surface of the frame member 23 by passing a screw 30 through an aperture 31 formed in the distal end wall of the connector via an opening 32 in the bottom face of the connector 1 . In this manner a rigid L-shaped structure is provided which forms two sides of the desired door frame. A groove 29 may extend longitudinally along the centre of the external channelled surface of the frame member 23. The groove 29 provides a seat for the tip of the screw 30 and prevents it from skidding during insertion.

The way in which the ribbed distal end of the connector 1 engages the channelled surface of the frame member 23 ensures an accurate alignment of the two frame members 23, 28 and it is almost impossible for the connector 1 to be rotated or misaligned and so provides the benefit of a flat front and rear face to the frame assembly with no projecting overlaps of metal or fixings.

The connector 1 comprises a pair of stops 33 which prevents the first end of the connector 1 being pushed too far into the frame member 28. The stops 33 are resiliency deflectable to allow the connector 1 to be urged into the frame member 28 if desired, the stops being arranged to frictionally engage the inner surface of the frame member 28 to prevent it from sliding fully inside.

The connector 1 is formed as a unitary moulding from plastics material and comprises an open front wall, and ribs 34 extending between its opposite side walls 35. The ribs 34 extend transversely of the connector 1 to define one or more voids 36 in which electrical outlet sockets can be mounted.

The first end portion 20 of the connector comprises a distal end face 37 which lies obliquely to the longitudinal axis of the first end portion 21 and comprises transversely extending recesses 38 on its opposite side faces. These recesses 38 perform the same function as the groove 10 at the second end portion 21 and, as shown in Figure 4D, provide an engagement structure for engaging channel-shaped frame members which lie at an oblique angle of 32 to 50 degrees to the frame member into which the second end 21 of the connector 1 is inserted. The first end 20 of the connector 1 can then be fixed in-situ by passing a screw through an elongate aperture 39 formed in the distal end face 37.

Referring also to Figures 7A to 7C of the drawings, the connector 1 comprises a transverse line of weakness 40 adjacent the first and second ends 20, 21 thereof. The lines 40 are of weakness are formed by moulding the walls of the connector 1 of thinner material at discrete regions along the line. The ends of the line where they meet edges of the connector are not reduced in thickness to prevent the connector 1 from inadvertently breaking. In use, a user simply has to cut the edges e.g. 41 with a cutting implement to allow the connector 1 to be snapped into two. This allows the connector 1 to be shortened, for example in applications where the frame member into which the connector 1 is inserted is short in length.

The connectors can be fixed rigidly at one or both ends to respective frame members after adjustment if required, for example by driving a screw through the relevant frame member into the connector. The frame members may comprise groves to assist with location of the screw. A connector in accordance with the present invention is simple and inexpensive in construction yet enables a wide variety of frame members to be easily and securely connected together using just one type of connector.

Claims

A connector for connecting together first and second elongate frame members, at least the first member comprising a hollow which extends axially along the member, at least the second member having a ribbed longitudinally extending profiled surface, the connector comprising:

a second end portion having a distal end face which lies perpendicular to the longitudinal axis of the first end portion and which comprises a profile which is complementary to the profiled surface of the second frame member; and a fastening arrangement for use in fastening said end face against the profiled surface of the second frame member.

A connector as claimed in claim 1 , comprising a stop which prevents the first end of the connector being pushed too far into the first frame member.

A connector as claimed in claim 2, in which the stop is resiliently deflectable to allow the connector to be urged into the first frame member, the stop being arranged to frictionally engage the inner surface of the first frame member to prevent it from sliding therein.

A connector as claimed in any preceding claim, in which the distal end face of the connector comprises a plurality of ribs for engaging with corresponding channels in the longitudinally extending profiled surface of the second member.

A connector as claimed in any preceding claim, in which the fastening arrangement comprises a formation in the distal end face of the connector, through which a screw can be inserted to engage the second frame member.

A connector as claimed in any preceding claim, in which the connector is also be arranged to connect elongate channel-shaped frame members having an open channel extending along the member and being partially enclosed by a lip extending along the opening, the channel having an opening along one side of the member, the first end portion of the connector being shaped to fit into the channel of a first channel-shaped frame member via one end thereof, the second end portion being shaped to permit its insertion into the channel of a second channel-shaped frame member via the opening therein when the connector is in a first rotational position with respect thereto, the second end portion comprising an engagement structure which is shaped to engage with the lip of the second channel-shaped frame member when the inserted connector is rotated within the channel from the first rotational position into a second rotational position with respect to the second channel-shaped frame member.

7. A connector as claimed in claim 6, in which the engagement structure comprises transversely extending slots on at least one pair of opposite side faces of the second end of the connector.

8. A connector as claimed in any preceding claim, in which the connector is frangible and comprises a transverse line of weakness extending transverse its longitudinal axis to enable the length of the connector to be shortened.

A connector as claimed in claim 8, in which the line of weakness extends from a point adjacent an edge of the connector and comprises a reduced wall thickness, the wall thickness at the edge being thicker than that of the line.

10. A connector as claimed in any preceding claim, in which the first end of the connector comprises a distal end face which lies obliquely to the longitudinal axis of the first end portion and which comprises transversely extending recesses on at least one pair of opposite side faces of the first end of the connector, said recesses forming an engagement structure for engaging a channel-shaped frame member which lies at an oblique angle of 32 to 50 degrees to a frame member into which the second end of the connector is inserted.

1 1 . A connector as claimed in claim 10 as appended to claims 8 or 9, in which the connector comprises a pair of said lines of weakness adjacent respective opposite ends thereof.

12. A connector as claimed in any preceding claim, in which the connector is hollow and comprises an open front wall, ribs extending between opposite side walls of the connector.

13. A connector as claimed in claim 12, in which the ribs extend transversely of the connector to define one or more voids which form pattresses.

14. A frame assembly comprising:

15. A frame assembly as claimed in claim 14, in which the distal end face of the connector comprises a plurality of ribs which engage with corresponding channels in the longitudinally extending profiled surface of the second member.

16. A frame assembly as claimed in claim 14 or 15, in which the fastening arrangement comprises a formation in the distal end face of the connector, through which a screw extends to engage the second frame member.

17. A frame assembly as claimed in any of claims 14 to 16, in which the assembly comprises a third frame member and a second said connector having its first elongate end portion slidably received in the hollow at the opposite end of the first frame member, the third frame member having an open channel extending along the member and being partially enclosed by a lip extending along the opening, the channel having an opening along one side of the member, the second end portion of the second connector being shaped to permit its insertion into the channel of the third frame member via the opening therein when the connector is in a first rotational position with respect thereto, the second end portion of the second connector further comprising an engagement structure which is shaped to engage with the lip of the third channel-shaped frame member when the second connector is rotated within the channel from the first rotational position into a second rotational position with respect to the second channel-shaped frame member.

18. A frame assembly as claimed in any of claims 14 to 17, in which the connector is a connector of any of claims 1 to 13.

19. A connector for connecting together first and second elongate frame members, one of the members comprising a hollow which extends axially along the member, the connector comprising:

20. A connector as claimed in claim 19, in which the second frame member has an open channel extending along the member and being partially enclosed by a lip extending along the opening, the second end portion of the connector comprising an engagement structure which is shaped to engage with the lip of the second member when the inserted connector is rotated within the channel of the second member from the first rotational position into a second rotational position with respect to the second member.

21 . A connector as claimed in claim 19, in which the second frame member has a ribbed longitudinally extending profiled surface, the second end portion of the connector having a distal end face which lies perpendicular to the longitudinal axis of the first end portion and which comprises a profile which is complementary to the profiled surface of the second frame member, the connector further comprising a fastening arrangement for use in fastening said end face against the profiled surface of the second frame member.

22. A connector as claimed in any of claims 14 to 17, in which the connector is a connector of any of claims 1 to 13.