A mitre joint

Abstract

A mitre joint for a metallic frame of a fenestration unit. The joint comprises: first and second frame members; a connector configured to locate the first and second frame members in relation to one another; and first and second fasteners configured to secure the first and second frame members respectively to the connector. The connector comprises a first arm configured to extend within a hollow profile defined by the first frame member, and a second arm configured to extend within a hollow profile defined by the second frame member. When the first and second arms extend within the corresponding frame members, the joint is configured such that one or each of the first and second fasteners is: co-axially receivable in a channel of the corresponding frame member via insertion through an external aperture in one of the frame members; and engageable with the corresponding frame member and connector arm when received in said channel to secure the frame member to the connector.

Description

FIELD

[0001] The present teachings relate to a mitre joint for a metallic frame of a fenestration unit, a connector for a mitre joint, a metallic frame comprising a mitre joint, a fenestration unit comprising a mitre joint, a kit of parts for a metallic frame of a fenestration unit, and a method of manufacturing a connector for a mitre joint.BACKGROUND

[0002] Frames for windows, doors and other types of fenestration unit are often provided by connecting a series of frame members with a joint at each corner of the frame.

[0003] It is known to assemble a metallic frame for a fenestration unit by attaching frame members to corner connectors, e.g. connecting four frame members at four corner connectors to create a standard four-sided frame. It is known to locate and secure a first frame member to a corner connector, and then to locate and secure a second frame member to that corner connector. Connecting frame members one at a time may be necessary due to the fastener arrangement used, or the design of the corner connector. However, such an arrangement often makes no allowance for inaccuracy during manufacture of the frame components, or damage that may occur to the frame components, for example during transport to a site. Misalignment of the frame members with respect to one another can result, so that a watertight or well insulated seal cannot be formed between a pane and the frame, so that the frame may not allow fitting of the required pane or panel, may not fit within the opening, or may simply not have a neat finish.

[0004] Other connection systems require a large investment in specialist machinery to simultaneously connect first and second frame members to a connector. Such systems use punches to deform the frame members to mechanically engage around the connector. This also prevents any subsequent adjustment of the alignment, so if not aligned properly during the operation, both frame members and the connector have to be scrapped.

[0005] There are other difficulties with existing joints. Transportation of several individual components may be required, during which components may be mislaid or separated from their assembly / remainder of the assembly. Joints may need to be assembled on site, which can be difficult with a number of intricate components. The fitting between each frame member and the connector may require the end of the frame member to have a particular internal profile, which may involve substantial amounts of material. This can be expensive in particular with e.g. aluminium frames.

[0006] Existing joints are known which include two outer frame members secured to each other via a first corner connector, and two inner frame members secured to each other via a second corner connector, where the outer frame members are on an outer face of the fenestration unit and the inner frame members are on an inner face, and the outer and inner frame members are connected to each other via further frame members. A problem with such joints is that the two corner connectors often need to be secured to at least two of the frame members substantially simultaneously so as to avoid stressing, and misaligning, the frame members. This can make assembly of such joints more time consuming, and / or necessitate specialist equipment.SUMMARY

[0007] The present invention seeks to overcome or at least mitigate one of more of the problems associated with the prior art.

[0008] According to a first aspect of the present teachings, there is provided a mitre joint for a metallic frame of a fenestration unit. The joint comprises: first and second frame members; a connector configured to locate the first and second frame members in relation to one another; and first and second fasteners configured to secure the first and second frame members respectively to the connector. The connector comprises a first arm configured to extend within a hollow profile defined by the first frame member, and a second arm configured to extend within a hollow profile defined by the second frame member. When the first and second arms extend within the corresponding frame members, the joint is configured such that one or each of the first and second fasteners is: co-axially receivable in a channel of the corresponding frame member via insertion through an external aperture in one of the frame members; and engageable with the corresponding frame member and connector arm when received in said channel to secure the frame member to the connector.

[0009] Advantageously, such a configuration enables the frame members to be accurately positioned relative to each other before the frame members are secured to the connector via the fasteners. This enables the joint to be assembled rapidly since it negates the need to repeatedly unsecure and secure the frame members to the connector to accurately align the frame members.

[0010] The or each external aperture may be substantially aligned with a longitudinal axis of the corresponding channel.

[0011] Such an alignment enables each fastener to be received in the corresponding channel quickly and easily, simplifying assembly of the joint.

[0012] The or each external aperture via which the corresponding fastener is receivable in the channel of the corresponding frame member may be in the other of the first and second frame members.

[0013] Such a configuration helps to simplify assembly of the joint.

[0014] The hollow profile of the or each frame member having an external aperture may comprise a passage from the external aperture in that frame member leading to the channel in the other frame member. The joint may be configured such that the corresponding fastener is receivable in the corresponding channel via the passage leading to that channel.

[0015] Such a configuration helps to simplify assembly of the joint.

[0016] Each passage may be formed via a punching or drilling process.

[0017] Each passage may be substantially aligned with the corresponding channel.

[0018] Such a configuration enables the mitre joint to be assembled easily and quickly.

[0019] When the first and second arms extend within the corresponding frame members, a longitudinal axis of the or each channel may be substantially parallel to a longitudinal axis of the corresponding connector arm.

[0020] Such a configuration helps to provide a more compact connector and may minimise the material to be removed from the frame members for insertion of the fasteners.

[0021] An axial portion of said one or each of the first and second fasteners may be configured to engage the corresponding channel so as to secure the fastener to the corresponding frame member.

[0022] Such a configuration helps to provide a strong connection between each fastener and corresponding frame member.

[0023] The axial portion may be a threaded axial portion.

[0024] The threaded axial portion may comprise a metric screw thread, e.g. a M8 screw thread.

[0025] Such screw threads are standardised and widely used, and so are low cost to obtain. Moreover, such screw threads provide high resistance to axial separation loads and thus help provide a strong connection between the frame members and the connector.

[0026] The threaded portion may be configured to be self-tapping.

[0027] Such a configuration helps to provide a strong connection between the fasteners and the frame members, and eases assembly of the joint.

[0028] Said one or each of the first and second fasteners may be a grub screw.

[0029] Such a configuration helps to provide a more compact mitre joint as a female tool interface minimises the required overall diameter of the fastener.

[0030] Said one or each of the first and second fasteners may comprise an unthreaded axial portion adjacent an end thereof arranged to engage the corresponding connector arm.

[0031] The unthreaded axial portion may assist with guiding the fastener into the channel before the threaded portion engages the frame member.

[0032] An end of said one or each of the first and second fasteners may be configured to engage the corresponding connector arm via abutment therewith so as to secure the corresponding frame member to the connector.

[0033] Such a configuration enables the joint to be assembled rapidly and easily, whilst providing a strong connection between the frame members and the connector.

[0034] The connector may be configured such that, when the first and second arms extend within the corresponding frame members, a path of said one or each of the first and second fasteners from the corresponding external aperture to the corresponding channel is clear of the connector.

[0035] Such a configuration helps to reduce the mass and cost to manufacture the connector.

[0036] Said path may not pass through the connector.

[0037] Each connector arm may comprise an elongate member arranged substantially parallel to a longitudinal axis of the corresponding frame member when extending therein. The elongate members of the connector arms may join to define an inner corner of the connector. The connector arm corresponding to said one or each of the first and second fasteners may comprise an engagement wall projecting from an end of the elongate member with respect to a frame comprising the joint. The corresponding fastener may be arranged to engage the engagement wall to secure the corresponding frame member to the connector.

[0038] Each elongate member may be received in a first void defined by the corresponding hollow profile. The elongate member and first void may have complementary profiles.

[0039] Such a configuration enables the elongate member to help locate the connector arm in the frame member, as well as provide support for the corresponding channel.

[0040] Each connector arm may comprise a support member transversely spaced from, and parallel to, the elongate member. The support member may be received in a second void defined by the corresponding hollow profile. The support member and second void may have complementary profiles.

[0041] Such a configuration enables the elongate member to help locate the connector arm in the frame member, as well as provide support for the corresponding channel.

[0042] The support members of the first and second connector arms may be spaced from each other.

[0043] Such a configuration helps to reduce the mass and cost to manufacture of the connector.

[0044] Each support member may extend less than 75%, e.g. less than 50%, e.g. less than 25% of a length of the corresponding elongate member.

[0045] The elongate members of the connector arms may join to define an external outer corner of the connector.

[0046] Such a configuration helps to reduce the mass and cost to manufacture of the connector.

[0047] The first and second arms may be joined exclusively via their respective elongate members.

[0048] The frame member profile corresponding to said one or each of the first and second fasteners may define at least two, e.g. three or four, projections extending from the profile. The projections may at least partially define the corresponding channel. The corresponding fastener may engage the projections when received in the channel to secure the fastener to the frame member.

[0049] Such a configuration enables frame members to be more lightweight, and cheaper to manufacture.

[0050] Each projection may engage the corresponding fastener at an engagement point. The projections may be configured such that the engagement points are substantially equidistant about a periphery of the fastener.

[0051] Distributing the engagement points substantially equidistant about the fastener helps to increase the stability of engagement between the fasteners and frame members.

[0052] Said one or each of the first and second fasteners may comprise a threaded axial portion. Each projection of the corresponding frame member may extend to a location between a minor diameter and major diameter of said threaded axial portion.

[0053] Such a configuration provides a strong connection between the fasteners and frame members.

[0054] The hollow profile and projections of said one or each frame member may be configured to locate the corresponding connector arm within the frame member.

[0055] When the first and second arms extend within the corresponding frame members, the joint may be configured such that said one or each of the first and second fasteners is removable from the frame members via the corresponding external aperture.

[0056] Such a configuration enables the joint to be quickly and easily disassembled.

[0057] The first and second arms may meet such that an angle between a longitudinal axis of each of the arms is in the range of 60 to 120 degrees; optionally, in the range of 75 to 105 degrees.

[0058] The connector may be formed from metal, e.g. aluminium.

[0059] Each frame member may comprise first and second frame profiles connected via a connector frame member. The first frame profiles of the first and second frame members may be secured to a first connector via corresponding first and second fasteners. The second frame profiles of the first and second frame members may be secured to a second connector via corresponding first and second fasteners.

[0060] The joint may further comprise a third frame member and a third fastener. The connector may be configured to locate the first, second and third frame members in relation to one another. The third fastener may be configured to secure the third frame member to the connector. The connector may comprise a third arm configured to extend within a hollow profile defined by the third frame member. When the third arm extends within the third frame member, the joint may be configured such that the third fastener is: co-axially receivable in a channel of the third frame member via insertion through an external aperture in one of the frame members; and engageable with the third frame member and connector arm when received in said channel to secure the third frame member to the connector.

[0061] The first and second connector arms may meet to form an inner corner of the connector with respect to a frame comprising the joint. A profile of the inner corner may be configured such that the first and second connector arms meet at a point.

[0062] Such a configuration helps to accurately locate the frame members relative to each other.

[0063] According to a second aspect of the present teachings, there is provided a connector for the joint of the first aspect. The connector may incorporate one or more of the features of the connector referred to in relation to the first aspect.

[0064] According to a third aspect of the present teachings, there is provided an at least partially metallic frame comprising the joint of the first aspect.

[0065] According to a fourth aspect of the present teachings, there is provided a fenestration unit comprising the joint of the first aspect, or the frame of the third aspect.

[0066] According to a fifth aspect of the present teachings, there is provided a kit of parts for a metallic frame of a fenestration unit. The kit of parts comprises: first and second frame members; a connector configured to locate the first and second frame members in relation to one another; and first and second fasteners configured to secure the first and second frame members respectively to the connector. The connector comprises a first arm configured to extend within a hollow profile defined by the first frame member, and a second arm configured to extend within a hollow profile defined by the second frame member. When the first and second arms extend within the corresponding frame members, the joint is configured such that one or each of the first and second fasteners is: co-axially receivable in a channel of the corresponding frame member via insertion through an external aperture in one of the frame members; and engageable with the corresponding frame member and connector arm when received in said channel to secure the frame member to the connector.

[0067] According to a sixth aspect of the present teachings, there is provided a method of manufacturing a connector for the joint of the first aspect or the kit of parts of the fifth aspect. The connector comprises a first arm configured to extend within a hollow profile defined by a first frame member, and a second arm configured to extend within a hollow profile defined by a second frame member. The method comprises: extruding a blank comprising a plurality of connectors arranged side-by-side along a first axis of the connectors perpendicular to the first and second arms; cutting the blank to remove one of the connectors therefrom; forming a profile of the first arm of the removed connector along a longitudinal axis thereof via a machining process; and forming a profile of the second arm of the removed connector along a longitudinal axis thereof via a machining process.BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Embodiments are now disclosed by way of example only with reference to the drawings, in which: Figure 1 is a side view of a fenestration unit according to an embodiment; Figure 2 is an isometric view of a mitre joint of the fenestration unit of Figure 1 in a fully assembled state according to an embodiment; Figure 3 is an isometric view of the mitre joint of Figure 2 in a first partially assembled state; Figure 4A is a profile view of a connector for the mitre joint of Figure 2; Figure 4B is an isometric view of the connector of Figure 4A; Figure 5 is an isometric view of the mitre joint of Figure 2 in a second partially assembled state; Figure 6 is a side view of the mitre joint of Figure 2; Figure 7 is a view along section A-A in Figure 2; Figure 8 is an isometric view of a window frame member of the mitre joint of Figure 2; Figure 9 is an isometric view of a mitre joint in a fully assembled state according to an embodiment; and Figure 10 is a side view of the mitre joint of Figure 9. DETAILED DESCRIPTION OF EMBODIMENT(S)

[0069] Figure 1 shows a fenestration unit generally indicated at 1. The fenestration unit 1 has a frame 2 made up of a series of frame members 12 connected at mitre joints 10. The fenestration unit 1 of this embodiment is suitable for a window, door or other type of fenestration, such as a vent. The frame 2 supports a pane or panel 3, such as a pane of glass, a double or triple glazed sealed unit, or a panel of wood, aluminium or other suitable material.

[0070] The frame 2 is a metallic frame, i.e. a frame having frame members 12 that are at least in part metallic. A metallic frame as described here may include features or components of some non-metallic or composite material, such as plastics material or wood.

[0071] A mitre joint 10 of the fenestration unit 1 is shown in Figure 2 in an assembled state. The joint 10 has first and second frame members 12a, 12b. When the joint 10 is in the assembled state shown in Figure 2 the frame members 12a, 12b meet to form a corner of the frame 2. First ends 14a, 14b of the frame members 12a, 12b are angled, as indicated at a, b, so as to form a mitre joint. In this embodiment, the first ends 14a, 14b are both angled at 45°, i.e. angle a is 45° and angle b is 45°.

[0072] In alternative embodiments, the first ends 14a, 14b have some other angle. For example, 'a' may be 60° and 'b' may be 30°, or 'a' and 'b' may have other suitable values. In such embodiments, the first and second frame members 12a, 12b may be of different widths to one another, so that the first ends 14a, 14b require different angles to one another.

[0073] In the illustrated embodiment, the frame members 12a, 12b form a 90° corner. In alternative embodiments the frame 2 may have corners of some other angle, e.g. between 60° and 120°, e.g. between 75 and 105 degrees.

[0074] In the illustrated embodiment, the frame member first ends 14a, 14b are of equal angles. In alternative embodiments, where the frame has a corner or corners of some non-90° angle, and where the first and second frame members 12a, 12b are of different widths to one another, the first ends 14a, 14b may be of different angles to one another.

[0075] In the illustrated embodiment, each frame member 12a, 12b includes first and second hollow metal (typically aluminium alloy) frame member profiles 22x, 22y connected via a connector frame member 102. When the fenestration unit 1 is on a perimeter of a structure, the first member profiles 22x may be on an external face of the fenestration unit 1, and the second member profiles 22y may be on an internal face, or vice versa. Each connector frame member 102 may include a thermal break (e.g. of plastics or foam material) configured to inhibit heat transfer between the corresponding first and second frame member profiles 22x, 22y via the connector frame member 102. The use of a thermal break is required such that windows of this type with structural aluminium frame member profiles 22x, 22y to meet the energy efficiency requirements of domestic and commercial external windows and doors.

[0076] The joint 10 includes two connectors 16, as shown in Figure 3. Each connector 16 locates the frame members 12a, 12b in relation to one another, and may be substantially L-shaped. With reference to Figures 4A and 4B, each connector 16 has a first arm 20a and a second arm 20b. Each arm 20a, 20b has a first, free, end 21, and a second end 23. The second ends 23 meet to form a corner 118 of the connector 16. In this embodiment, where the frame members 12a, 12b form a 90° corner, the connector arm second ends 23 meet at a 90° angle. In embodiments where the frame 2 has corners of some other angle, the connector arms meet at a corresponding angle.

[0077] In alternative embodiments (not shown), the joint 10 may include only a single connector 16, or more than two connectors 16.

[0078] Each connector 16 may be formed from metal (e.g. aluminium, an aluminium alloy, or steel), plastics, or from any suitable material.

[0079] In the illustrated embodiment, the first arms 20a of the connectors 16 are configured to extend within the first and second member profiles 22x, 22y of the first frame member 12a respectively to locate the first frame member 12a. The second arms 20b of the connectors 16 are configured to extend within the first and second member profiles 22x, 22y of the second frame member 12b respectively to locate the second frame member 12b.

[0080] Each connector arm 20a, 20b is receivable in the corresponding hollow member profile 22x, 22y when respective first and second longitudinal axes Xa, Xb thereof are aligned, as shown in Figure 6.

[0081] With reference to Figures 5 and 6, the joint 10 includes two pairs of first and second fasteners 18a, 18b configured to secure the frame members 12a, 12b to the connectors 16.

[0082] A first pair of fasteners 18a, 18b is configured to secure the first member profiles 22x of the first and second frame members 12a, 12b to one of the connectors 16. A second pair of fasteners 18a, 18b is configured to secure the second member profiles 22y of the first and second frame members 12a, 12b to the other connector 16. The securing arrangement of the first member profiles 22x to the corresponding connector 16 is substantially identical to the securing arrangement of the second member profiles 22y to the corresponding connector 16. As such, only the former of these securing arrangements shall be discussed in the following for brevity.

[0083] Figure 5 shows the connector arms 20a, 20b extending within the first member profiles 22x before the frame members 12a, 12b are secured to the connector 16 (which is shown in phantom in Figure 5) via the fasteners 18a, 18b. The joint 10 is configured such that, when the connector arms 20a, 20b extend within the corresponding frame members 12a, 12b, the first and second fasteners 18a, 18b are co-axially receivable in respective first and second channels 106a, 106b of the first and second frame members 12a, 12b respectively. In the illustrated embodiment, said first and second channels 106a, 106b are in the first frame member profiles 22x of the first and second frame members 12a, 12b.

[0084] The first and second fasteners 18a, 18b are engageable with the corresponding frame member 12a, 12b and connector arm 20a, 20b when received in the corresponding channel 106a, 106b to secure that frame member 12a, 12b to the connector 16.

[0085] The joint 10 is configured such that each fastener 18a, 18b is receivable in the corresponding channel 106a, 106b via insertion through an external aperture 108a, 108b in one of the frame members 12a, 12b. By "external aperture", it is intended to mean an aperture in a surface of the frame member which will be on the exterior of said frame member once the joint 10 is fully assembled. Each external aperture 108a, 108b is sized to allow the corresponding fastener 18a, 18b to pass therethrough. In the illustrated embodiment, a minimum diameter of each external aperture 108a, 108b is greater than a maximum diameter of a profile of the corresponding fastener 18a, 18b.

[0086] Advantageously, such a configuration of the joint 10 enables the frame members 12a, 12b to be accurately positioned relative to each other via the connector 16 before the frame members 12a, 12b are secured to the connector 16 via the fasteners 18a, 18b. This enables the joint 10 to be assembled rapidly since it negates the need to repeatedly unsecure and secure the frame members 12a, 12b to the connector 16 to accurately align the frame members 12a, 12b. Further, such a configuration enables each connector 16 to be secured to the frame members 12a, 12b separately (i.e. not simultaneously), further simplifying assembly of the joint 10.

[0087] As shown in Figure 6, in the fully assembled state of the joint 10, the first connector arm 20a, the first channel 106a, the first fastener 18a and the first frame member 12a are aligned with the first longitudinal axis Xa. Likewise, the second connector arm 20b, the second channel 106b, the second fastener 18b and the second frame member 12b are aligned with the second longitudinal axis Xb. In alternative embodiments (not shown), one or more of the corresponding connector arms 20a, 20b, channels 106a, 106b, fasteners 18a, 18b and frame members 12a, 12b may be positioned so as to have a different longitudinal axis (i.e. having a different position relative to the corresponding first or second longitudinal axis Xa, Xb).

[0088] In the illustrated embodiment, the first external aperture 108a is substantially aligned with the first longitudinal axis Xa. The second external aperture 108b is substantially aligned with the second longitudinal axis Xb. Such an alignment enables each fastener 18a, 18b to be received in the corresponding channel 106a, 106b rapidly and easily.

[0089] In the illustrated embodiment, the first external aperture 108a is in the second frame member 12b. The second external aperture 108b is in the first frame member 12a. Such a configuration may help to provide a more compact connector 16, smaller external apertures 108a, 108b, and simplify assembly of the joint 10.

[0090] Figure 7 shows a view of first member profile 22x of the first frame member 12a and first fastener 18a along section A-A in Figure 2, which is substantially identical to corresponding views of the second frame member profile 22y but with the orientation changed accordingly.

[0091] In the illustrated embodiment, each frame member profile 22x, 22y defines four projections 24 extending from the profile 22x, 22y to engage the respective fastener 18a, 18b. The projections 24 at least partially define the corresponding channel 106a, 106b. Each fastener 18a, 18b engages the projections 24 when received in the corresponding channel 106a, 106b to secure the fastener 18a, 18b to the frame member 12a, 12b.

[0092] In alternative embodiments (not shown), each channel 106a, 106b may have any suitable configuration, e.g. defined by an internal wall of the frame member profile 22x, 22y.

[0093] The projections 24 engage the fasteners 18a, 18b at discrete, separate engagement points 26, where each engagement point is distinct from the next. The projections 24 are arranged about the fasteners 18a, 18b such that the engagement points 26 provide balanced support, e.g. such that the engagement points 26 are evenly arranged about a periphery of each fastener 18a, 18b. Advantageously, this arrangement provides stability to the engagement between each fastener 18a, 18b and frame member 12a, 12b whilst reducing the amount of material used in the profile 22x, 22y. Providing an engagement point 26 rather than a solid block or a face of a profile wall or the like for fastener engagement can also improve ease of engagement, in particular where the fastener is a self-tapping screw, due to the reduced amount of material used.

[0094] In the illustrated embodiment, engagement of the projections 24 and the fasteners 18a, 18b at the engagement points 26 cover less than 25% of the total circumference of each fastener 18a, 18b. In alternative embodiments, the engagement points cover less than 50% of the total periphery of each fastener, or less than 35%.

[0095] In the illustrated embodiment, two projections 24 extend from a first side 28 of each profile 22x, 22y, and two projections 24 extend from a second side 30 of each profile 22x, 22y. The projections 24 oppose one another and are arranged so that the four engagement points 26 are equidistant to one another about the periphery of the respective fastener 18a, 18b. In alternative embodiments, with a profile defining four projections, the projections 24 may be arranged such that the engagement points form opposing pairs, i.e. so that the projections extending from a first side of each profile create engagement points that oppose those created by the projections extending from a second side of each profile, yet the engagement points are not equidistant from one another.

[0096] In alternative embodiments (not shown) each frame member profile may define two projections, or three projections, or five or more projections. In some embodiments with even numbers of projections, the projections are arranged in pairs. In some such embodiments, the pairs of projections are equidistant one another about the periphery of each fastener.

[0097] In the illustrated embodiment, the second side 30 of each profile 22x, 22y is configured to engage the connector frame member 102 to connect thereto.

[0098] In the illustrated embodiment, a threaded axial portion T of each fastener 18a, 18b is configured to engage the corresponding channel 106a, 106b to secure the fastener 18a, 18b to the corresponding frame member 12a, 12b. In alternative embodiments (not shown), each fastener 18a, 18b may additionally or alternatively include an axial portion configured to engage the corresponding channel 106a, 106b via any suitable means, e.g. via an interference fit. For example, the fastener may be radially expandible to frictionally engage the walls of the channels 106a, 106b.

[0099] Each threaded axial portion T may have a major diameter in the range of 6 to 10mm, e.g. 7 to 9mm, e.g. approximately 8.0mm. Each channel 106a, 106b may have a diameter in the range of 5 to 9mm, e.g. 6 to 8mm, e.g. approximately 7.0mm.

[0100] In the illustrated embodiment, each fastener 18a, 18b is a grub screw, which helps to reduce the width of the external apertures 108a, 108b and channels 106a, 106b needed to receive the fasteners 18a, 18b since they do not need to accommodate a larger diameter fastener head.

[0101] In the illustrated embodiment, each threaded portion T is configured to cut threads into the projections 24 when driven into the corresponding channel 106a, 106b (i.e. the threaded portion T is self-tapping). This helps to provide a strong connection between the fasteners 18a, 18b and the frame members 12a, 12b, and eases manufacture of the joint 10. In alternative embodiments (not shown), one or both channels 106a, 106b may include pre-formed threads for engagement with the corresponding fastener.

[0102] The threaded axial portion T may include a metric screw thread, e.g. a M8 screw thread. Such screw threads are standardised and widely used, and so are low cost. Such screw threads also provide high resistance to axial separation loads and thus help provide a strong connection between the frame members 12a, 12b and the connector 16.

[0103] In the illustrated embodiment, the projections 24 extend substantially to a minor diameter of the threaded portion T of each fastener 18a, 18b. That is, the projections 24 extend to substantially the full depth of the trough of the fastener thread. A high level of engagement between the fasteners 18a, 18b and the respective frame member 12a, 12b is thus achieved. In alternative embodiments, each projection 24 may extend to any location between a minor diameter and major diameter of the corresponding threaded axial portion T.

[0104] In the illustrated embodiment, each fastener 18a includes an unthreaded axial portion U adjacent an end 112 thereof. The unthreaded axial portion U may help guide the fastener 18a, 18b into the corresponding channel 106a, 106b before the threaded axial portion T engages said channel 106a, 106b.

[0105] With reference to Figure 6, the joint 10 is configured such that the end 112 of each fastener 18a, 18b engages the corresponding connector arm 20a, 20b via abutment therewith so as to secure the corresponding frame member 12a, 12b to the connector 16. Such a configuration provides a strong connection between the frame members 12a, 12b and the connector 16.

[0106] The first member profile 22x of the second frame member 12b includes a first passage 110a from the first external aperture 108a leading to the first channel 106a in the first frame member 12a. Likewise, the first member profile 22x of the first frame member 12a includes a second passage 110b from the second external aperture 108b leading to the second channel 106b in the second frame member 12b. The joint 10 is configured such that each fastener 18a, 18b is receivable in the corresponding channel 106a, 106b via the passage 110a, 110b leading to that channel 106a, 106b.

[0107] In the illustrated embodiment, the first passage 110a is aligned with the first longitudinal axis Xa. The second passage 110b is aligned with the second longitudinal axis Xb. In alternative embodiments (not shown), one or both passages 110a, 110b may not be so aligned.

[0108] The joint 10 is configured such once both frame members 12a, 12b have been secured to the connector 16 via the fasteners 18a, 18b as shown in Figure 6, each fastener 18a, 18b is removable from the frame members 12a, 12b via the corresponding passage 110a, 110b and external aperture 108a, 108b. Such a configuration enables the joint 10 to be quickly and easily disassembled.

[0109] With reference to Figure 8, each passage 110a, 110b is formed by removing material from the corresponding profile 22x, 22y (e.g. from the projections 24) to form a cylindrical void (represented by dotted lines in Figure 8) extending from the external aperture 108a, 108b through the hollow profile 22x, 22y. Each passage 110a, 110b and corresponding external aperture 108a, 108b may have substantially the same diameter. Each passage 110a, 110b may be formed via a punching and / or drilling process, for example.

[0110] In the illustrated embodiment, each projection 24 includes a root portion 24a and a tip portion 24b. Each root portion 24a joins to the remainder of the profile 22x, 22y. Each tip portion 24a extends from a corresponding root portion 24a, and engages the corresponding fastener 18a, 18b. Each tip portion 24b extends at angle to the corresponding root portion 24a. In the illustrated embodiment, each passage 110a, 110b is formed by removing material from the tip portions 24b of the projections 24 only, i.e. no material is removed from the root portions 24a. This has been found to simplify formation of the passages 110a, 110b, since the tip portions 24b provide less resistance to machining than the root portions 24a. Material may also be removed from the root portions 24a in alternative embodiments.

[0111] With reference to Figures 4A and 4B, each connector arm 20a, 20b includes an elongate member 120 and an engagement wall 122. Each elongate member 120 is arranged substantially parallel to the corresponding common longitudinal axis Xa, Xb when extending within the corresponding hollow profile 22x, 22y. The elongate members 120 include the second ends 23 of the connector arms 20a, 20b, which join to form the corner 118 of the connector 16. In the illustrated embodiment, the corner 118 includes an inner corner 118i and outer corner 118o of the connector 16, where "inner" and "outer" are used with respect to the frame 2. The inner and outer corners 118i, 118o are on the exterior of the connector 16.

[0112] Each engagement wall 122 projects from an end of the elongate member 120 distal the corner 118. Each engagement wall 122 projects outwardly with respect to the frame 2. As shown in Figure 6, the end 112 of each fastener 18a, 18b is arranged to abut the corresponding engagement wall 122 to secure the corresponding frame member 12a, 12b to the connector 16.

[0113] In the illustrated embodiment, each engagement wall 122 projects substantially perpendicular to the corresponding elongate member 120, but may extend at any suitable angle in alternative embodiments (e.g. between 45 and 135 degrees to the corresponding elongate member 120).

[0114] The profile 22x, 22y and projections 24 of each frame member 12a, 12b are configured to locate the corresponding connector arm 20a, 20b therein. With further reference to Figure 7, the profile 22x, 22y and projections 24 of each frame member 12a, 12b define a first void 130a and a second void 130b. The two voids 130a, 130b are located either side of the channel 106a, 106b.

[0115] In the illustrated embodiment, each elongate member 120 is received in the first void 130a. The elongate member 120 and first void 130a have complementary profiles so as to locate the connector arm 20a, 20b in the frame member 12a, 12b. Moreover, such an arrangement of the elongate member 120 and first void 130a enables the elongate member 120 to support the adjacent projections 24 when the corresponding fastener 18a, 18b engages them. In the illustrated embodiment, said complementary profiles are rectangular but may have any suitable shape.

[0116] In the illustrated embodiment, the end portion 104 of each connector arm 20a includes a support member 126 opposing, and substantially parallel to, the elongate member 120. Each support member 126 is received in a second void 130b. The support member 126 and second void 130b have complementary profiles so as to locate the connector arm 20a, 20b in the frame member 12a, 12b and support the adjacent projections 24.

[0117] The complementary profiles of the elongate members 120 and first voids 130a, and support members 126 and second voids 130b are configured such that engagement therebetween couples the connector arms 20a, 20b and frame members 12a, 12b to each other about their longitudinal axes Xa, Xb. Moreover, such engagement may provide some resistance to relative translation of the connector arms 20a, 20b and frame members 12a, 12b along their longitudinal axes Xa, Xb due to friction. Hence, when the connector arms 20a, 20b extend within the hollow profiles 22x, the connector 16 maintains a relative position of the frame members 12a, 12b before the fasteners 18a, 18b are secured in placed.

[0118] In the illustrated embodiment, the support member 126 is adjacent the engagement wall 122. The support member 126, engagement wall 122 and elongate member 120 define a recess 124 in which the end 112 of the corresponding fastener 18a, 18b is received.

[0119] In the illustrated embodiment, the support members 126 of the first and second connector arms 20a, 20b are spaced from each other, i.e. they do not contact each other. In alternative embodiments (not shown), the support members 126 may instead join to form an outer corner of the connector 16.

[0120] Each support member 126 extends less than 25% of a length of the corresponding elongate member 120, which helps to reduce the mass and cost to manufacture of the connector 16. In alternative embodiments (not shown), each support member 126 may extend more than 25% but less than 50% or less than 75% of the length of the elongate member 120. Alternatively, the support member 126 may extend 100% or more of the length of the elongate member 120.

[0121] The connector 16 is configured such that, when the first and second arms 20a, 20b extend within the corresponding frame members 12a, 12b, the path of each fastener 18a, 18b from the corresponding external aperture 108a, 108b, along the corresponding passage 110a, 110b to the corresponding channel 106a, 106b for engagement with the corresponding engagement wall 122 is clear of the connector 16.

[0122] In the illustrated embodiment, the first and second connector arms 20a, 20b are joined solely via their respective elongate members 120. This not only helps to reduce the mass and cost to manufacture of the connector 16, but also ensures that said path of each fastener 18a, 18b is clear of the connector 16. In the illustrated embodiment, said path of each fastener 18a, 18b does not pass through the connector 16. In alternative embodiments, such a path may pass through an aperture in a wall of the connector 16.

[0123] In the illustrated embodiment, an end portion 104 of each arm 20a, 20b has a substantially I-shaped profile, but may alternatively have a T-shaped profile, or any suitably shaped profile for coupling the arms 20a, 20b to the frame members 12a, 12b, e.g. any profile including a plurality of transverse protrusions.

[0124] In the illustrated embodiment, the end portion 104 of each connector arm 20a, 20b includes a chamfered leading edge 132 to aid in guiding each connector arm 20a, 20b into the corresponding hollow profile 22x, 22y.

[0125] In the illustrated embodiment, a profile of the inner corner 118i is configured such that the connector arms 20a, 20b meet at a point as shown in Figure 4A, which helps to accurately locate the frame members 12a, 12b relative to each other.

[0126] The connector 16 may be formed via an extrusion process. Such a process may include: extruding a blank comprising a plurality of connectors 16 arranged side-by-side along a first axis of the connectors 16 perpendicular to the connector arms 20a, 20b (i.e. oriented into the page in Figure 4A); cutting the blank to remove one of the connectors 16 therefrom; forming a profile of the first arm 20a of the removed connector 16 along the first longitudinal axis Xa via a machining process (e.g. drilling, milling, cutting); and forming a profile of the second arm 20b of the removed connector 16 along the second longitudinal axis Xb via a machining process.

[0127] Advantageously, it has been found that forming the connector 16 via such an extrusion process increases its durability such that the first and second connector arms 20a, 20b can be joined solely via their respective elongate members 120 without significantly affecting the integrity of the connector 16.

[0128] In alternative embodiments (not shown), the connector 16 may be formed via any suitable process, e.g. casting (e.g. die casting), forging, moulding, and / or additive manufacturing.

[0129] The joint 10 can be assembled according to the following method: i) inserting the first connector arms 20a of the connectors 16 into the first frame member profile 22x and second frame member profile 22y of the first frame member 12a respectively; ii) inserting the second connector arms 20b of the connectors 16 into the first frame member profile 22x and second frame member profile 22y of the second frame member 12a respectively; iii) securing the first frame member 12a to the connectors 16 via the corresponding first fasteners 18a; and iv) securing the second frame member 12b to the connectors 16 via the corresponding second fasteners 18b.

[0130] It will be appreciated that the order of the steps may be altered.

[0131] Once secured, relative movement of the frame members 12a and 12b are prevented towards each other by the contact of the mitred surfaces, and away from each other by the fasteners 18a, 18b being axially constrained in the frame members by the threaded interface and the ends of the fasteners abutting the engagement walls 122.

[0132] Advantageously, each of steps i)-iv) be performed quickly and easily using only basic hand tools (e.g. such as a screwdriver or Allen key).

[0133] In the foregoing description, both frame members 12a, 12b are secured to the connector 16 via the first and second fasteners 18a, 18b as described above. In alternative embodiments (not shown), a fastener may secure one of the frame members 12a, 12b to the connector 16 via a different means.

[0134] Figures 9 and 10 show a mitre joint 10' according to further embodiment. Features common with the joint 10 of Figures 2 to 8 share common reference numerals and a discussion of which shall not be repeated for brevity. The joint 10' may share any of the features described in relation to the joint 10 and vice versa.

[0135] The joint 10' includes first, second and third frame members 12a, 12b, 12c'. The connector 16' of this embodiment is configured to locate the first, second and third frame members 12a, 12b, 12c' in relation to one another.

[0136] In the illustrated embodiment, the first and second frame members 12a, 12b are substantially perpendicular. The second and third frame members 12b, 12c' are substantially perpendicular. The first and third frame members 12b, 12c' are substantially parallel. In alternative embodiments (not shown), the frame members 12a, 12b, 12c' may have any suitable relative positions.

[0137] The joint 10' includes first, second and third fasteners 18a, 18b, 18c' configured to secure the first, second and third frame members 12a, 12b ,12c' respectively to the connector 16'.

[0138] The connector 16' includes first, second and third arms 20a, 20b, 20c' configured to extend within hollow profiles defined by the first, second and third frame members 12a, 12b, 12c'.

[0139] When the connector arms 20a, 20b, 20c' extend within the corresponding frame members 12a, 12b, 12c', the joint 10' is configured such that each fastener 18a, 18b, 18c is co-axially receivable in a channel 106a, 106b, 106c' of the corresponding frame member 12a, 12b, 12c' via insertion through an external aperture 108' in one of the frame members 12a, 12b ,12c'. Each fastener 18a, 18b, 18c is engageable with the corresponding frame member 12a, 12b ,12c' and connector arm 20a, 20b, 20c' when received in said channel to secure the frame member 12a, 12b, 12c' to the connector 16'.

[0140] In the illustrated embodiment, the frame members 12a, 12b ,12c' include a single external aperture 108' formed in the first and third frame members 12a, 12c', but may have two or more external apertures 108' in alternative embodiments (e.g. one in each of the first and third frame members 12a, 12c'. The aperture 108' may be in the form of an elongate slot spanning the first and third frame members 12a, 12c' enabling each fastener 18a, 18b, 18c' to be inserted at a suitable angle.

[0141] In the illustrated embodiment, a passage 110a, 110b, 110c' extends from the external aperture 108' to each channel 106a, 106b, 106c'. The joint 10' is configured such that each fastener 18a, 18b, 18c' is receivable in the corresponding channel 106a, 106b, 106c' via the passage 110a, 110b, 110c' leading to that channel 106a, 106b, 106c'.

[0142] In the illustrated embodiment, only the second passage 110b and channel 106b are aligned with the external aperture 108'. The external aperture 108' and the first and third passages 110a, 110c' are sized to enable the first and third fasteners 18a, 18c' to be received in the corresponding channels 106a, 106c' via the external aperture 108' and corresponding passages 110a, 110c'. The external aperture 108' and first and third passages 110a, 110c' are also sized so as to enable a tool 140', such as a ball headed Allen key, to drive the first and third fasteners 18a, 18c' into engagement with the corresponding channels 106a, 106c', as shown in Figure 10.

[0143] In the foregoing description, all three frame members 12a, 12b, 12c' are secured to the connector 16' via the first, second and third fasteners 18a, 18b, 18c' as described above. In alternative embodiments (not shown), a fastener may secure one of the frame members 12a, 12b, 12c' to the connector 16' via a different means.

Claims

1. A mitre joint for a metallic frame of a fenestration unit, the joint comprising: first and second frame members; a connector configured to locate the first and second frame members in relation to one another; and first and second fasteners configured to secure the first and second frame members respectively to the connector, wherein the connector comprises a first arm configured to extend within a hollow profile defined by the first frame member, and a second arm configured to extend within a hollow profile defined by the second frame member, wherein, when the first and second arms extend within the corresponding frame members, the joint is configured such that one or each of the first and second fasteners is: co-axially receivable in a channel of the corresponding frame member via insertion through an external aperture in one of the frame members; and engageable with the corresponding frame member and connector arm when received in said channel to secure the frame member to the connector.

2. The joint of claim 1, wherein the or each external aperture is substantially aligned with a longitudinal axis of the corresponding channel.

3. The joint of claims 1 or 2, wherein the or each external aperture via which the corresponding fastener is receivable in the channel of the corresponding frame member, is in the other of the first and second frame members, optionally, wherein the hollow profile of the or each frame member having an external aperture comprises a passage from the external aperture in that frame member leading to the channel in the other frame member, and wherein the joint is configured such that the corresponding fastener is receivable in the corresponding channel via the passage leading to that channel; optionally, wherein each passage is formed via a punching or drilling process, wherein each passage is substantially aligned with the corresponding, optionally, wherein, when the first and second arms extend within the corresponding frame members, a longitudinal axis of the or each channel is substantially parallel to a longitudinal axis of the corresponding connector arm.

4. The joint of any preceding claim, wherein an axial portion of said one or each of the first and second fasteners is configured to engage the corresponding channel so as to secure the fastener to the corresponding frame member, optionally, wherein the axial portion is a threaded axial portion; optionally, wherein the threaded axial portion comprises a metric screw thread, e.g. a M8 screw thread, and / or wherein said one or each of the first and second fasteners is a grub screw, optionally, wherein said one or each of the first and second fasteners comprises an unthreaded axial portion adjacent an end thereof arranged to engage the corresponding connector arm.

5. The joint of claim 4, wherein an end of said one or each of the first and second fasteners is configured to engage the corresponding connector arm via abutment therewith so as to secure the corresponding frame member to the connector, optionally wherein the abutment is configured to engage an end of the or each fastener at an end of the fastener distal the corner.

6. The joint of any preceding claim, wherein the connector is configured such that, when the first and second arms extend within the corresponding frame members, a path of said one or each of the first and second fasteners from the corresponding external aperture to the corresponding channel is clear of the connector; optionally, wherein said path does not pass through the connector.

7. The joint of any preceding claim, wherein each connector arm comprises an elongate member arranged substantially parallel to a longitudinal axis of the corresponding frame member when extending therein, wherein the elongate members of the connector arms join to define an inner corner of the connector, wherein the connector arm corresponding to said one or each of the first and second fasteners comprises an engagement wall projecting from an end of the elongate member with respect to a frame comprising the joint, and wherein the corresponding fastener is arranged to engage the engagement wall to secure the corresponding frame member to the connector, optionally, wherein each elongate member is received in a first void defined by the corresponding hollow profile, and wherein the elongate member and first void have complementary profiles, optionally, wherein each connector arm comprises a support member transversely spaced from, and parallel to, the elongate member, wherein the support member is received in a second void defined by the corresponding hollow profile, and wherein the support member and second void have complementary profiles; optionally, wherein the support members of the first and second connector arms are spaced from each other; optionally, wherein each support member extends less than 75%, e.g. less than 50%, e.g. less than 25% of a length of the corresponding elongate member.

8. The joint of any one of claim 7, wherein the elongate members of the connector arms join to define an external outer corner of the connector; optionally, wherein the first and second arms are joined exclusively via their respective elongate members.

9. The joint of any preceding claim, wherein the frame member profile corresponding to said one or each of the first and second fasteners defines at least two, e.g. three or four, projections extending from the profile, wherein the projections at least partially define the corresponding channel, and wherein the corresponding fastener engages the projections when received in the channel to secure the fastener to the frame member; optionally, wherein each projection engages the corresponding fastener at an engagement point, and wherein the projections are optionally configured such that the engagement points are substantially equidistant about a periphery of the fastener.

10. The joint of any preceding claim, wherein, when the first and second arms extend within the corresponding frame members, the joint is configured such that said one or each of the first and second fasteners is removable from the frame members via the corresponding external aperture, and / or, wherein each frame member comprises first and second frame profiles connected via a connector frame member, wherein the first frame profiles of the first and second frame members are secured to a first connector via corresponding first and second fasteners, and wherein the second frame profiles of the first and second frame members are secured to a second connector via corresponding first and second fasteners.

11. A connector for the joint of any preceding claim.

12. An at least partially metallic frame comprising the joint of any one of claims 1 to 10.

13. A fenestration unit comprising the joint of any one of claims 1 to 10, or the frame of claim 12.

14. A kit of parts for a metallic frame of a fenestration unit, the kit of parts comprising: first and second frame members; a connector configured to locate the first and second frame members in relation to one another; and first and second fasteners configured to secure the first and second frame members respectively to the connector, wherein the connector comprises a first arm configured to extend within a hollow profile defined by the first frame member, and a second arm configured to extend within a hollow profile defined by the second frame member, wherein, when the first and second arms extend within the corresponding frame members, the kit of parts is configured such that one or each of the first and second fasteners is: co-axially receivable in a channel of the corresponding frame member via insertion through an external aperture in one of the frame members; and engageable with the corresponding frame member and connector arm when received in said channel to secure the frame member to the connector.

15. A method of manufacturing a connector for the joint of any one of claims 1 to 10, or for the kit of parts of claim 14, wherein the connector comprises a first arm configured to extend within a hollow profile defined by a first frame member, and a second arm configured to extend within a hollow profile defined by a second frame member, the method comprising: extruding a blank comprising a plurality of connectors arranged side-by-side along a first axis of the connectors perpendicular to the first and second arms; cutting the blank to remove one of the connectors therefrom; forming a profile of the first arm of the removed connector along a longitudinal axis thereof via a machining process; and forming a profile of the second arm of the removed connector along a longitudinal axis thereof via a machining process.

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