GB2271798A

GB2271798A - Joints in window frames formed from metal extrusions

Info

Publication number: GB2271798A
Application number: GB9222113A
Authority: GB
Inventors: Suee Pi Tang
Original assignee: SOLITE IMPEX Pte Ltd
Current assignee: SOLITE IMPEX Pte Ltd
Priority date: 1992-10-21
Filing date: 1992-10-21
Publication date: 1994-04-27
Also published as: GB9222113D0

Abstract

A window frame comprises lengths of metal extrusion cut from longer extrusions, the extrusions being cut in a plane perpendicular to their long axes, and connecting pieces acting so as to form joints between the lengths of metal extrusion. The connecting pieces have at least one tongue complementary in shape to a cavity formed within the lengths of extrusions such that the tongue may be received by a cavity in a length of extrusion so as to form the desired joint. By joining lengths of extrusion cut in this way, the wastage associated with the conventional means of joining lengths of extrusion is avoided. The connecting pieces can be used to form corner-joints, cross-joints and tee-joints in inner and outer window and door frames and can be of ABS, uPVC or wood.

Description

WINDOW FRAMES FORMED FROM METAL EXTRUSIONS This invention relates to window frames formed from lengths of metal extrusion cut from longer lengths of extrusion.

For many years window frames and outer frames have been manufactured from metal extrusions. Frames formed from metal extrusions are very popular as they are easy to maintain and are extremely durable. Furthermore, the extrusions can be moulded into specific shapes so that hinge means, locking means etc. may be concealed within the extrusions. Many casement and fanlight windows, singly or doubly glazed, as well as the supporting outer frames therefor, are now formed from metal extrusions, particularly aluminium extrusions which are long lasting, easy to mould and attractive to look at.

However, there are a number of problems associated with the formation of window frames and outer frames from metal extrusions. The metal extrusions come in standard lengths which are then cut to appropriate lengths to form the sides of the metal frames. Conventionally, in forming a corner joint the cut lengths are joined by a mitre joint, which requires that the metal extrusions be cut diagonally at a 45- angle. This leads to a great deal of wastage. For example, one of the standard lengths of aluminium extrusions currently available from suppliers is 6. 1 m long. One of the standard casement window frames currently manufactured has outer dimensions of 70 cm x 40 cm. Thus, each casement frame requires 2. 2 m of the aluminium extrusion.Three such windows would therefore require 6. 6 m of aluminium extrusion, such that the standard length aluminium extrusion is not sufficiently long to form three such casement window frames. Thus, the requirement to cut the extrusions diagonally leads to considerable wastage.

Additionally, the formation of the mitre joint requires a fair degree of skill. The extrusions must be cut at 45 angles before joining the ends together. The sharp edges formed must be filed and a special clamp is then required to hold the four corners together while the joints are fixed with rivets or screws. If the special clamp is not used, there is a tendency for gaps to form at the joints. This method of forming the joints in the frames is both difficult and time consuming.

Another problem often encountered in producing window frames is where it is desired to form one or more divisions, either vertical (mullions) or horizontal, between the lights of the window. Again, specialised clamps are required to hold the extrusions together and a great deal of skill is required to cut the ends of the extrusions to the appropriate shape and to attach them so as to form the desired joint.

It can be seen, therefore, that there is a need for a quick and simple means for forming joints between lengths of metal extrusion which does not require specialist skill and equipment, and which cuts down the wastage that is caused as a result of the type of joints that are currently employed. It is these problems that the present invention addresses.

In addressing these problems, the present inventors have developed a window frame which comprises lengths of metal extrusion cut from longer extrusions, the extrusions being cut in a plane perpendicular to their long axes, and connecting pieces acting so as to form joints between the lengths of metal extrusion. The connecting pieces have at least one tongue complementary in shape to a cavity formed within the lengths of extrusions such that the tongue may be received by a cavity in a length of extrusion so as to form the desired joint.

Thus, according to the present invention, there is provided a window frame comprising lengths of metal extrusion secured by connecting pieces, the lengths of extrusion being prepared from longer extrusions by cutting in a plane perpendicular to the long axes thereof and being so formed as to define at least one cavity therein, the connecting pieces having at least one tongue so configured as to form a snug fit with at least one cavity in a length of extrusion, the connecting pieces also being securable to at least one other length of extrusion.

It will be appreciated that the term window frame encompasses both frames for holding the lights of a window, including door frames for doors having windows, and also the supporting frames for such frames.

The connecting pieces of the present invention allow the metal extrusions to be cut perpendicularly rather than diagonally, as is required for the conventional mitre joint. By cutting the extrusions perpendicularly the wastage represented by the extra diagonal piece on each cut length is saved. Furthermore, formation of both corner and mullion joints and the like is considerably easier than using the conventional techniques outlined earlier. No specialised clamps are required, the connecting pieces slotting easily into place.

The joints formed between the lengths of extrusion may be corner joints, the connecting pieces forming the corner joints acting to substantially fill the space between the joined lengths of extrusion so as to convey a continuous appearance between the joined lengths of extrusion. For example, the window frame may be one having substantially square corners, the connecting pieces then having a substantially cuboidal central body, a pair of mutually perpendicular tongues extending from said central body.

In a further embodiment, the window frame of the invention may have vertical or horizontal members, formed from lengths of extrusion, which act to form divisions between the lights of the window, the ends of the dividing members being connected to the sides of the frame by means of connecting pieces, each connecting piece having a substantially flat face for abutment to the side of the window frame to which the dividing member is attached and means within the face to enable the socket pieces to be connected to the side of the window, each connecting piece further having a tongue extending perpendicularly to the plane of the substantially flat face of the connecting piece, the tongue being complementary in shape to a cavity in the length of extrusion forming the dividing member.

As has been discussed earlier, the extrusions to be joined together will typically be aluminium extrusions.

In a further aspect of the present invention, connecting pieces for use in the manufacture of the window frames of the invention are provided. For example, for square or rectangular window frames, a connecting piece is provided for joining two or more lengths of metal extrusion in the manufacture of said window frames, the end faces of each length of extrusion being perpendicular to the long axis of the length of extrusion, the connecting piece being such that it enables joints to be formed between the lengths of extrusion in which the end faces of the lengths of extrusion joined are mutually perpendicular.

Typically, the connecting pieces are formed from a durable plastic such as ABS (acrylonitrile-butadiene-styrene copolymers) or uPVC (unplasticised polyvinyl chloride). Alternatively, the socket pieces may be formed, for example, from a suitable wood. The particular form of the connecting pieces will vary depending on the type of joint to be formed. Using these connecting pieces it is possible to form strong, long-lasting joints between lengths of metal extrusion so as to form window frames and supporting outer frames for windows, without the wastage and difficulty associated with current methods of forming joints between lengths of metal extrusions.

In one embodiment of the connecting piece of the invention, a corner connecting piece is provided, a pair of tongues extending from a central body such that the tongues are at the desired angle of the joint to be formed between the lengths of extrusion, the shape of the tongues being complementary to a cavity defined by the cross sectional shape of the lengths of metal extrusion to be joined and the length thereof, such that in use the complementarily shaped tongues may be received snugly by the cavities in the lengths of extrusion to be joined so as to form the desired corner joint, the central body acting so as to substantially fill the space between the joined lengths of extrusion.

In a substantially square or rectangular window frame, the connecting piece of the invention has a wholly or partially cuboidal central body, a pair of tongues extending from the central body in a mutually perpendicular direction, e. g. the central body may be substantially L-shaped, tongues extending axially from the end of each of the arms such that the tongues are mutually perpendicular.

In a typical casement window frame, for example, the substantially L-shaped central body of a corner connecting piece will have a recess surrounding the complementarily shaped tongue such that when the tongue is received by length of extrusion, there is a flush fit between the central body of the connecting piece and the edges of the length of extrusion.

The central body of the connecting piece may have further sections on the sides thereof, the dimensions of the L-shaped portion and the side pieces being chosen such that they are complementary to the dimensions of the end faces of the lengths of extrusion to be joined, so that when the joints are formed the connecting piece acts to fill the space between the joined extrusions to form a continuous, substantially square face to the corner joint similar to that obtained by the conventional mitre joint. The side pieces may be integrally moulded with the remainder of the connecting piece, if it is formed from plastic, or they may be added metal pieces, the metal being the same as that from which the extrusion is formed from, so as to form apparently "seamless" corner joints.

Further features may be incorporated into the central body, if required, e. g. a groove, complementary to a groove on the metal extrusions to be joined, to accept a rubber insulating strip.

The corner connecting piece for the formation of a supporting outer frame is substantially the same as that for the formation of a frame, the additional features being shaped so as to enable attachment of the outer frame, formed using the connecting pieces, to the wall.

It is a feature of this invention that the tongues are so configured that they form a snug fit when inserted into cavities formed within the lengths of extrusion to be joined. It should be appreciated that each tongue may be divided into a number of smaller elements complementary in shape to cavities within the extrusions to be joined. The precise nature of the tongues may vary somewhat. The tongues may be parallel-sided members which may be easily slotted in an axial direction into the complementarily shaped cavity in the length of the extrusion to be formed. Alternatively, the tongues may be wedge shaped so as to form a tighter fit in the cavities into which they are inserted. The latter style of tongue might typically be used where no additional means for fixed attachment of the connecting pieces to the lengths of extrusion are provided.

The connecting pieces of the invention may have means that enable the connecting pieces to be fixedly attached to the extrusions once they are in place to form the desired joint between the extrusions. Typically, these will take the form of receiving means moulded into the connecting piece, suitably placed such that when the connecting piece is in place the receiving means are aligned with complementary receiving means in the lengths of extrusion to be joined, screws, rivets or the like then being driven through the aligned receiving means to fixedly attach the connecting piece to the lengths of extrusion.

In a further embodiment of the connecting piece of the invention, a connecting piece is provided for use in the formation of joints between lengths of metal extrusion forming the sides of a window frame and lengths of metal extrusion forming vertical or horizontal dividing members between the lights of a window (e.g. mullion joints), the connecting piece having a body with a substantially flat base for abutment to a face of a length of extrusion to be used in forming a side of a window frame, means being provided in this substantially flat base to enable it to be attached to said face of said length of extrusion, the main body of the connecting piece extending from the substantially flat base such that a pair of opposing faces of the body are substantially T-shaped, a tongue extending from the distal end of the main body in a direction perpendicular to the plane of the substantially flat base, the shape of the tongue being complementary to a cavity defined by the cross sectional shape of the length of metal extrusion to be used in forming a dividing member and the length thereof, such that in use the substantially flat base may be affixed to the appropriate face of the length of extrusion forming the side of a frame to be formed, the tongue being received by the cavity in the length of extrusion forming the vertical or horizontal dividing member so as to form the desired joint.

In another embodiment of the invention, a connecting piece is provided that acts as a means of connecting more than two lengths of extrusion together at a single junction. In a square or rectangular window, for example, which is divided into four lights by the use of horizontal and vertical members, a central connecting piece is used to connect the dividing members. Such a connecting piece is configured such that each adjoining pair of tongues is mutually perpendicular, i.e. the tongues are arranged in a cross-like configuration.

Similar central connecting pieces may be envisaged in which the relative configuration of the tongues of the connecting piece is determined by the angles between the dividing members to be joined.

There is also provided a method of forming a window frame from lengths of metal extrusion comprising the following steps: (a) cutting metal extrusions in a plane perpendicular to the long axis of the extrusion to form shorter lengths of metal extrusion; and (b) connecting the lengths of extrusion so as to form the desired frame by means of the connecting pieces of the invention.

Claims

1. A window frame comprising lengths of metal extrusion secured by connecting pieces, the lengths of extrusion being prepared from longer extrusions by cutting in a plane perpendicular to the long axes thereof and being so formed as to define at least one cavity therein, the connecting pieces having at least one tongue so configured as to form a snug fit with at least one cavity in a length of extrusion, the connecting pieces also being securable to at least one other length of extrusion.

2. A frame according to claim 1, wherein at least one connecting piece is securable to said other length of extrusion by means of a tongue as defined.

3. A frame according to claim 1 or 2, wherein the tongue is unitary or comprised of two or more elements.

4. A frame according to any preceding claim, wherein at least one connecting piece is so configured as to convey a continuous appearance between the lengths of extrusion connected by it.

5. A frame according to any preceding claim, wherein at least one connecting piece has two tongues and no other means of connection.

6. A frame according to any preceding claim, comprising four connecting pieces serving as corner joints.

7. A frame according to any preceding claim, in which the connecting pieces are formed from a durable plastic.

8. A frame according to claim 7, wherein the connecting pieces are formed from ABS (acrylonitrile-butadienestyrene copolymer) or uPVC (unplasticised polyvinyl chloride).

9. A window frame according to any preceding claim, wherein the extrusions are of aluminium.

10. A connection piece for use in window frames formed from lengths of metal extrusion, as defined in any preceding claim.

11. A method of forming a window frame from lengths of metal extrusion comprising: (a) cutting metal extrusions in a plane perpendicular to the long axis of the extrusion to form shorter lengths of metal extrusion; and (b) connecting the lengths of extrusion so as to form the desired frame using connecting pieces as defined in claim 10.