IE860710L - Corner joint for window frame - Google Patents

Description

. s V 4 S# t> 01 This invention relates to connectors and in particular to connectors for connecting adjacent mitred ends of two elongate hollow frame elements of substantially rectangular-section to form a mitred 05 corner joint.

The rail and stile members of door and window frames are commonly formed as extrusions of hollow rectangular-section cut to length and the adjacent ends joined to form a rectangular frame of any. desired size. 10 Several methods for joining the adjacent ends of rail and stile members have been proposed previously including the use of both internal devices which are hidden and external devices which are exposed.

Internal devices are preferred as providing a neater 15 finish and these are known for producing both a butt joint and a mitred joint.

A disadvantage of the butt joint is that the end of one of the frame elements is open allowing the entry of water and debris into the frame section. Mitred 20 joints are therefore generally preferred as providing a joint in which the ends of both frame elements are closed.

The known internal devices for connecting hollow frame elemients include an L-shaped cleat device each 25 limb of which is received within the hollow section of a respective one of the frame elements. The limbs may be an interference fit within the section, for example formed with deformable burrs or the like to retain the limb in the frame section without the use of screws or 30 the like fasteners. Alternatively the frame elements 01 may be formed with one or more pre-drilled holes for the insertion of screws to engage tapped holes in the limbs.

A disadvantage of such cleat devices is that it is 05 often difficult to align the ends of the frame elements accurately and to prevent relative movement between the ends of the frame elements in the plane of the joint on assembly. Consequently the ends of the frame elements in the finished joint may be off-set which is both 10 undesirable and unsightly.

It is an object of the present invention to provide a connector for forming a mitred corner joint between elongate hollow frame elements of substantially rectangular-section which overcomes the foregoing 15 disadvantage of the known connectors.

According to a first aspect of the present invention we provide a mitred joint comprising first and second elongate hollow frame elements with abutting mitred ends, each frame element being of substantially 20 rectangular section having an inner web seated against a first insert secured within the section of the first frame element and projecting into the section of the second frame element, a second insert secured within the hollow section of the second frame element, the 25 first and second inserts having opposed abutment surfaces slidably engaging each other in a direction perpendicular to the plane of the joint, and a releasable fastener member extending in a direction perpendicular to the plane of the joint to connect the 30 first and second inserts together.

In the invented mitre joint, the mitred ends of two elongate hollow frame elements of substantially rectangular-section are accurately joined together by 01 locating and maintaining the adjacent ends in the required relationship by respective inserts secured within each frame element and connected by a releasable fastener member. .05 Each insert preferably extends between opposed front and rear walls of the associated frame element * and is secured to an outer web of the frame element.

Preferably, each insert comprises a substantially V-shaped body having a pair of limbs terminating in 10 respective co-planar attachment feet secured to the outer web of the associated frame element. The inserts may be secured by means of one or more screws extending through pre-drilled holes in the outer web of the associated frame element and engaging tapped holes in 15 the attachment feet.

The inserts are preferably extrusions of metal or alloy but plastics materials may be used depending on strength requirements. The frame elements are preferably extrusions of metal, alloy or plastics or 20 composites thereof. In this way, the inserts and frame elements may conveniently be cut to length from extrusions of the appropriate section.

The releasable fastener member preferably comprises a screw connecting the inserts together. 25 Preferably, the inserts are releasably secured, for example by means of set screws.

Advantageously, the secured position of the second insert is adjustable.

According to a second aspect of the present 30 invention we provide a door or window frame having a ' mitred joint according to the first aspect of the I' invention. 01 Other features and advantages of the invention will be apparent from the following description of one embodiment, given by way of example only, with reference to the accompanying drawings wherein:-05 FIGURE 1 is an exploded perspective view of a mitred corner joint according to the present invention: and FIGURE 2 is a part-sectional view of the corner joint shown in Figure 1 in the assembled condition. 10 Referring to the accompanying drawings, there is shown a mitred corner joint 1 between two elongate hollow frame elements 2,3 (part only shown) of substantially rectangular-section, such as rail and 01 stile members of a door or window frame. In a typical door or window frame of rectangular shape the rails form upper and lower cross members, the stiles form upright side members and there would be four such 05 joints, one at each corner of the frame, connecting adjacent ends of rail and stile members. In addition, i there may be one or more intervening mullions extending between the opposed stiles and joined thereto by any ^ suitable means. The assembled frame may be glazed or 10 panelled in known manner.

The frame elements 2,3 are of similar section, although this is not essential, each comprising front and rear walls 4 and 5 respectively connected by opposed inner and outer webs 6 and 7 respectively. The 15 outer web 7 is recessed between the edges of the front and rear walls which are formed with opposed inwardly directed lips 8 and 9 respectively to retain a cover strip (not shown) or the like. A flange 10 contiguous with the rear wall 5 forms a bead for locating glazing 20 or panelling (not shown) and is provided with longitudinally extending ribs 11 to engage a sealing strip (not shown) in known manner.

The frame elements 2,3 consist of extrusions of metal or alloy of the above-described section which are 25 cut to length and the adjacent ends mitred at 45° and connected by a connector 12 to form the corner joint 1.

By varying the length of the frame elements any desired size of frame may be produced.

The connector 12 comprises a pair of 30 inserts 13,13' and a releasable fastener , member constituted by a screw 14.

Each insert 13,13' comprises a generally V-shaped l- body 15,15' having a pair of limbs 16,16* extending 01 normal to each other and terminating at the base in respective co-planar attachment feet 17,17'.

Each insert 13,13* is located within the hollow rectangular section of a respective one of the frame 05 elements and is secured adjacent to the mitred end thereof by a pair of set screws 18 which extend through pre-drilled holes 19 in the outer web 7 of the frame element and engage tapped holes 20 in the attachment feet 17,17*. The insert bodies 15,15' extend 10 transversely with respect to the length of the frame elements and are of a length slightly less than the distance between the front and rear walls 4 and 5 so as to be a sliding fit therein.

The insert 13 is formed, on that side which, in 15 the assembled condition faces insert 13', with two longitudinal ribs 21,22, one at the apex of the body and the other adjacent to the base of the body. The ribs 21,22 extend transversely to the length of the frame element 2 and normal to the plane P of the 20 joint 1 between the frame elements 2,3. In the assembled condition, the ribs 21,22 project into the section of the other frame element 3 to locate the front and rear walls 4 and 5 of both frame elements relative to each other. In this way any twisting of 25 the frame elements 2,3 is avoided and the strength and rigidity of the resultant joint 1 is increased.

In addition, the apex rib 21 engages the inner web 6 of the frame element 2 on insertion of the insert 13 to position the insert 13 in the box-section 30 of the frame element 2 and provides a surface against which the inner web 6 of the other frame element 3 abuts in the assembled condition. In this way the inner webs 6 of both frame elements 2,3 are accurately 01 located relative to each other on assembly and outwards sliding movement in the direction of arrow A of the end of the frame element 3 relative to the end of the frame element 2 in the plane P of the joint 1 is prevented. 05 The insert 13' is formed, on that side which, in the assembled condition faces the insert 13, with a longitudinal rib 23 adjacent to the base of the body. „ The rib 23 extends transversely to the length of the frame element 3 and normal to the plane P of the 10 joint 1 between the frame elements 2,3. In the assembled condition, the rib 23 terminates flush to the end surface of the frame element 3, although this is not essential, and ribs 22,23 provide opposed abutment surfaces slidably engaging each other in a direction 15 normal to the plane P of the joint 1. In this way inwards sliding movement in the direction of arrow B of the end of the frame element 3 relative to the end of the frame element 2 in the plane P of the joint 1 is prevented. The pre-drilled holes 19 in the outer web 7 20 of the frame element 3 are slightly oversize to allow some adjustment in the position of the insert 13' to ensure the rib 23 is correctly positioned to slidably engage the rib 22 when the inner webs 6 of both frame elements 2,3 are accurately located by the rib 21. 25 The inserts are fastened together to complete the corner joint by the screw 14 which is inserted through a clearance opening 24 in the frame element 3 and a hole 25 in the insert 13" to engage an aligned tapped hole 26 in the insert 13. The screw head 27 is 30 recessed in the body 15' of the insert 13* and the aligned holes 25,26 in the inserts extend normal to the ^ plane P of the joint 1 between the frame elements 2,3. 01 In this way, on tightening the screw 14, the frame elements 2,3 are drawn together evenly whilst being retained in the required relationship by the abutment of the inner webs 6 against the rib 21 and by the 05 sliding engagement of the ribs 22,23.

As will now be appreciated the connector 12 enables the mitred ends of the frame elements 2,3 to be assembled and joined together with a high degree of accuracy by locating the inner webs 6 relative to each 10 other and maintaining the adjacent abutting ends of the frame elements 2,3 against relative inwards or outwards sliding movement in the plane P of the joint 1 therebetween.

The inserts may be of metal or alloy, for example 15 aluminium alloy, or alternatively plastics materials may be used depending on the strength requirements. The inserts may be formed by casting or machining but are preferably cut to length from an extrusion of the appropriate section.

The invention is not restricted to the embodiment above-described, for example the precise shape of the inserts may be altered as may the materials from which the inserts are formed to suit any particular application.

Also, the inner web of the frame elements may be slotted or apertured to allow drainage in known manner, for example the inner web may be formed by inturned flanges of the front and rear walls to form a continuous central slot extending lengthwise of the 30 frame element.

The frame elements may be of metal or alloy as described or, alternatively, of a suitable plastics material or a metal/plastics composite or an alloy/ plastics composite.

Claims (10)

01 Claims;

1. A mitred joint comprising first and second elongate hollow frame elements with abutting mitred ends, each frame element being of substantially 05 rectangular section having an inner web seated against a first insert secured within the section of the first s frame element and projecting into the section of the second frame element, a second insert secured within * the hollow section of the second frame element, the 10 first and second inserts having opposed abutment surfaces slidably engaging each other in a direction perpendicular to the plane of the joint, and a releasable fastener member extending in a direction perpendicular to the plane of the joint to connect the 15 first and second inserts together.

2. A mitred joint according to Claim 1 wherein each insert extends between opposed front and rear walls of the associated frame element and is secured to an outer web of the frame element. 20

3. A mitred joint according to Claim 2 wherein each insert comprises a substantially V-shaped body having a pair of limbs terminating in respective co-planar attachment feet secured to the outer web of the associated frame element. 25

4. A mitred joint according to Claim 3 wherein the inserts are extrusions of metal, alloy or plastics.

5. A mitred joint according to any one of the preceding Claims wherein the frame elements are extrusions of metal, alloy or plastics or composites 30 thereof. i.

6. A mitred joint according to any one of the preceding Claims wherein the releasable fastener member it comprises a screw.

7. A mitred joint according to any one of the preceding Claims wherein the inserts are releasably secured.

8. A mitred joint according to any one of the preceding Claims wherein the second insert is adjustably secured.

9. A mitred joint according to Claim 1 substantially as hereinbefore described with reference to the accompanying drawings.

10. A door or window frame having a mitred joint according to any one of the preceding Claims. F. R. KELLY & CO., AGENTS FOR THE APPLICANTS.