GB2290573A

GB2290573A - Template sub-frame for door or window installation

Info

Publication number: GB2290573A
Application number: GB9509875A
Authority: GB
Inventors: Roger Gamble; Antony Lee Hughes; John Lannigan; David John Jolly
Original assignee: Epwin Group PLC
Current assignee: Epwin Group PLC
Priority date: 1994-06-20
Filing date: 1995-05-16
Publication date: 1996-01-03
Also published as: GB9412307D0; GB9509875D0

Abstract

The invention provides a template sub-frame for use in defining a door or window aperture during the construction of a wall or similar structure. The sub-frame comprises two or more lengths (2, 3, 4, 8) of strip material joined together at at least one of the corners of the sub-frame by means of a separate corner piece (11, 12, 15, 16) which corner piece is securable to the lengths of strip material. Flaps 6 and 10 can be provided for retaining a door frame, window frame or sill. The corner piece can comprise two separate components which can each be separately secured together to form the complete corner piece. <IMAGE>

Description

TEMPLATE SUB-FRAME FOR DOOR OR WINDOW INSTALLATION Field of the Invention This invention relates to a template sub-frame for use in defining a door or window aperture during the construction of a wall or similar structure. The invention provides the template sub-frame itself, its use during the construction of a structure and component parts of the template sub-frame.

Background to the Invention When installing door or window assemblies in a wall or similar structure, the unglazed door or window frame may be used as a template to define an appropriate aperture in the brick, block or stone of the structure. The structure is constructed around the frame, which is subsequently glazed to form the completed door or window assembly.

More recently, it has become the practice to use, instead of the unglazed door or window frame, a temporary template frame to define the door or window aperture during construction. This avoids damage to the door or window frame itself. The template frame is removed prior to fitting the final door or window assembly into the aperture.

Alternatively, a "sub-frame" may be used as the template, not only to define the door or window aperture during construction, but also subsequently to provide a means for locating and in some cases securing the final door or window frame into position.

This type of template remains in the finished construction in addition to the door or window frame itself.

Several problems are experienced when using such subframes, notably their lack of rigidity and their relatively high cost. Also, in particular with metal sub-frames, the securing together of the corners of the sub-frame can involve the use of complex and costly welding techniques, the welds often being needed in relatively inaccessible positions, or the use of intricate screw and insert arrangements. It is an aim of the present invention to provide a template sub-frame of the type described, which overcomes or at least mitigates the above described problems.

Statements of the Invention According to a first aspect of the present invention there is provided a template sub-frame for use in defining a door or window aperture during the construction of a wall or similar structure. The subframe comprises two or more lengths of a strip material joined together at at least one of the corners of the sub-frame, the strip material having means by which it may be located in, and preferably secured to, the structure under construction. The lengths of strip material are joined together at said at least one of the corners by means of a separate corner piece made of a suitable material, which corner piece is securable to the lengths of strip material.

An important feature of the present invention is the use of separate corner pieces to hold together the components, i.e the lengths of strip material, of the template sub-frame. The corner pieces are preferably made from a plastics material, since such pieces are relatively inexpensive to produce. They may be made, for example, from PVC-u, from which many other conventional door and window components are constructed. They may be made from a recycled plastics material, for instance a PVC-u re-grind, leading to increased environmental acceptability and reduced cost. They may be formed, in particular, by extrusion or moulding.

In one embodiment of the invention, the corner pieces are formed by machining an existing PVC-u extrusion, such as would typically be used as a profile in a door or window assembly, to the desired shape. This is a highly convenient and inexpensive way of producing the corner pieces.

Corner pieces made from a plastics material are also much easier to weld together, either prior to use or on site, than are metal sub-frame components.

Techniques for welding together plastics door and window components are already widely available and relatively easy to use.

Thus, the template sub-frame of the present invention combines the advantages of conventional sub-frames, i.e it may be used to define a door or window aperture during construction and to provide a simple and reliable means for securing a door or window frame in position in a structure, with the additional advantages of ease of construction and use, relatively low cost and, due to the presence of the corner pieces in the sub-frame, accuracy in construction and high rigidity and strength of the sub-frame itself.

Indeed, the template sub-frame of the present invention can possess at least the same degree of rigidity and strength that would be expected of a fully welded metal sub-frame.

The lengths of strip material from which the sub-frame is constructed may be entirely conventional - their form is not in itself critical to the present invention. Typically, they will be made of a metal such as steel, although they may alternatively be made of a plastics material to avoid problems of heat transfer associated with metal components. They will preferably have a box-like, or substantially box-like (e.g. C-shaped), cross-section, at least partly hollow. They must have means by which they may be located in, and preferably secured to, the structure under construction (for instance, they may be locatable in, or securable to an element already located in, the cavity of a cavity wall). They also preferably have means for engaging a door or window frame which is inserted into the aperture they define, once construction of the wall or other structure has been completed.

The or each corner piece may comprise two separate components securable together to form the complete piece, each of which components may be secured to one of the lengths of the strip material so as to join together the two lengths at a corner of the sub-frame.

These components may be secured together (typically by hot fusion welding or adhesive means) prior to being secured to two lengths of the strip material to form a corner of the sub-frame. Alternatively, each component may be separately secured to one of the lengths of the strip material, and the two components subsequently secured together (again, typically by welding or the use of an adhesive) so as to join together the two lengths of strip material.

The corner piece is preferably adapted to be insertable into, and to fit firmly inside, substantially without movement, the strip material.

Its shape should thus be appropriate to theshape of the strip material. More preferably, the or each length of strip material and/or the or each corner piece is provided with engaging means by which the strip material may engage with an inserted corner piece so as to hold it in its correct poSition. Such engaging means may take the form, for example, of flaps or tangs provided at appropriate positions on the strip material.

However, the corner piece may be secured to the strip material in any other appropriate way. For instance, the strip material and corner piece may be so shaped that portions of the strip material are received in channels or slots provided in the corner piece, and those portions of the strip material and/or the inside walls of the channels or slots may be appropriately profiled so as to engage positively with one another.

Additionally or alternatively, the strip material and the corner piece may be provided with holes which, after assembly of the sub-frame, are aligned with one another so as to admit a fastening means such as a screw, a plastic (eg. nylon) rivet or the like, by which the strip material and corner piece may be more permanently secured together.

When the corner piece is intended to fit firmly inside the strip material, problems can sometimes be encountered during, and subsequent to, the fitting of the corner piece. If the corner piece is designed to fit too tightly inside the strip material, it can be damaged on insertion - for instance, a layer of plastic might be shaved off the edge of a plastics corner piece, or the corner piece may be caused to crack. At the same time, the sides of the strip material may well be pushed outwards by the inserted corner piece, thus opening up an undesirable clearance between the sides of the strip material and the corner piece. In contrast, if the corner piece is designed to fit too loosely inside the strip material, it can often become too easily dislodged on handling the assembled sub-frame.

Such problems can be overcome in a number of ways, including those described above which ensure better engagement between the corner piece and the strip material. Firstly, one or more edges of the corner piece may be chamfered, so as to provide a smoother lead-in when the corner piece is inserted into the strip material. Additionally or alternatively, any splaying of the strip material, caused by the inserted corner piece, can be corrected by crimping (ie. press forming) one or more sections of the strip material onto or into the inserted corner piece - this provides a positive mechanical engagement between the two components and hence strengthens the assembled subframe.

Because the corner piece must be securable to, and preferably insertable into, the strip material, its size and shape will depend on that of the strip material with which it is to be used. An additional component may be provided to form part of such a corner piece, the additional component being securable to the corner piece, for instance to its inside face, so as to alter its overall size and shape. Two or more such additional components may be used together, for instance arranged perpendicularly to one another around the inside of the corner piece and interengaging with one another in an appropriate fashion.

The use of such additional components provides great versatility, in terms of the size and shape of strip material with which the corner piece may be combined to form a sub-frame in accordance with the invention.

The template sub-frame of the present invention is usually square or rectangular in shape, although other shapes are possible. Typically, it will comprise a top and two sides, made from three lengths of strip material secured together by means of separate corner pieces, and a bottom which may be made from a strip material having a different cross-sectional profile to that of the top and side pieces, in order to be securable to a door or window sill in the finished structure.

According to a second aspect of the present invention, there is provided the use of the template sub-frame of the first aspect, during the construction of a wall or similar structure. The sub-frame may be used in exactly the same way as is a conventional sub-frame, as a template to define a door or window aperture both during and after construction.

According to a third aspect of the invention, there is provided a corner piece, preferably made from a plastics material, for use as part of the template sub-frame of the first aspect of the invention.

According to a fourth aspect, there is provided a component of such a corner piece, as described above, which component is separately securable to (preferably insertable into) a length of strip material, and securable to another such component so as to form a complete corner piece in accordance with the third aspect of the invention.

According to a fifth aspect, the invention provides the use of a corner piece according to the third aspect, or of a component according to the fourth aspect, in the assembly of a template sub-frame in accordance with the first aspect of the invention.

This use, i.e the assembly of the sub-frame, may take place on site (i.e at the site where the structure is to be constructed) immediately prior to use of the sub-frame.

The present invention will now be described, by way of example only, with reference to the accompanying illustrative drawings, of which: Figure 1 is a perspective view of a template sub-frame in accordance with the first aspect of the present invention; Figure 2 is a section along the line AA in Figure 1; Figure 3 is a section along the line BB in Figure 1; Figure 4 is a perspective view of a corner piece in accordance with the third aspect of the invention; Figure 5 is a perspective view of a component of the corner piece of Figure 4, in use in part of a template sub-frame such as is shown in Figure 1; Figures 6A - 6R are cross-sections through alternative corner pieces in accordance with the third aspect of the invention; Figures 7A - 7C illustrate how an alternative corner piece, in accordance with the invention, may be formed from an existing PVC-u extrusion and subsequently used;; Figure 8A is a perspective view of yet another corner piece in accordance with the invention Figure 8B is a section taken along the line XX in Figure 8A; Figure 8C is a section taken along the line YY in Figure 8A; Figure 9 is a schematic section through a corner piece similar to that of Figure 8, in use, showing an alternative method for securing the corner piece to a length of strip material; and Figures lOA & lOB are perspective views of additional components for use as part of a corner piece in accordance with the third aspect of the present invention.

Detalled Description of the Drawings Figure 1 shows a template sub-frame 1 in accordance with the first aspect of the present invention. The sub-frame comprises a top 2 and two sides 3, 4, each made from a length of steel strip 5 having a C-shaped box-like cross-sectional profile, as shown in Figure 2. The strip 5 is provided along its length with a number of flaps 6, by means of which it may be secured to a door or window frame which will be installed into the aperture 7 defined by the sub-frame 1. The strip is also securable to a second frame element (not shown) which may be located in the cavity of a cavity wall.

The bottom 8 of the sub-frame 1 is made from a length of steel strip 9 having the cross-sectional profile shown in Figure 3 and securable by means of flaps 10 to a door or window sill.

The components 2, 3 and 4 are secured together at their corners by means of plastics corner pieces 11 and 12, which are located inside the C-shaped metal strips 5. Figure 2 shows how the corner piece 12 fits snugly inside the strip 5, without movement. In an alternative embodiment of the sub-frame shown in Figure 1, additional resilient flaps would be provided on the shorter sides of each strip 5, so as to engage with the inserted corner piece 12 and hold it firmly in position.

Figure 4 shows the corner piece 11 (or 12) separated from the sub-frame. The corner piece is made from an extruded, recycled, plastics material. It comprises two components 13,14 secured together to form a rightangled corner piece. Component 13 is shown in Figure 5, already inserted into the metal strip 5 (only part of which is shown in Figure 5) ready for assembly of the complete template sub-frame of Figure 1.

As described above, the components 13, 14 may be separately inserted into the metal strips and then secured together to form a completed corner joint, or alternatively they may be secured together to form a corner piece such as is shown in Figure 4, which is then pressed into place inside two lengths of strip material to form part of a complete sub-frame.

Returning to Figure 1, sub-frame components 3 and 4 are secured to strip 8 by means of corner pieces 15, 16. Each of these corner pieces is effectively made up of two components, one the same as component 13 and the other (component 17 shown in Figures 1 and 3) of a slightly different cross-sectional profile so as to be insertable into the strip 8. The two components are secured together, conveniently by welding, to form the complete corner piece 15 or 16, thus to hold together the bottom and sides of the overall sub-frame 1.

Thus, it can be seen that a sub-frame in accordance with the present invention may be made up of lengths of strip material having different cross-sectional profiles, held together at the corners by means of corner pieces which are appropriately shaped to fit with the relevant cross-sectional profiles.

Figures 6A-6R show, in cross-section, alternative designs of corner piece in accordance with the present invention. Pieces A-G are for insertion into a subframe profile consisting of a 20 mm wide C-shaped steel channel; pieces H-K for insertion into a 10 mm wide C-shaped steel channel; and pieces L-R for insertion into a 35 mm wide C-shaped steel channel.

The corner pieces shown are intended to be made from PVC-u. The dimensions illustrated are in millimetres.

All radii are 0.5 mm unless otherwise stated.

Standard tolerances apply unless otherwise stated; in particular, for dimensions up to 4.0 mm, the tolerance is +/- 0.2; for those above 4.0 mm, +/- 0.3. The angular tolerance is +/- 10.

Figure 7 shows how an alternative corner piece 20 in accordance with the invention (cross-sectional profile shown in Figure 7A) can be manufactured by machining an existing PVC-u extrusion (the dashed line 21 in Figure 7B) typical of PVC-u profiles used in door and window assemblies. The corner piece is machined to have chamfered edges 22, 23. Figure 7C shows how the finished corner piece 20 fits tightly inside a steel channel 24 from which a template sub-frame in accordance with the invention is constructed.

Figure 8 shows yet another corner piece, 25, in accordance with the invention. The piece is moulded, in this case, from either a plastics material or from a die-cast metal. It comprises an "upper" portion 26 and a "lower" portion 27, joined by a neck portion 28, which together define slots 29 into which the arms of a C-shaped steel channel (forming part of a sub-frame) may be fitted in use. The clearance between the upper and lower portions depends on the thickness of the steel channel, as can be seen from Figure 8C.

Engagement between the corner piece 25 and the steel channel is achieved in use by means of profiling on the inside walls of the slots 29 (see Figure 8B), which helps to grip the inserted arms of the channel.

For additional security, an arrangement such as is shown in Figure 9 may be used. Here, extra holes 32 have been punched into a steel channel 33, close to its ends, to align with holes 34 in the corner piece 35. The corner piece is secured to the steel channel by means of pins (made for instance from nylon), plastic rivets, screws or other suitable fastening means, through the aligned holes 32 and 34. This makes the assembled sub-frame (ie. comprising both corner pieces and lengths of strip material) more secure during storage, transportation and use.

The corner piece may also be provided with one or more core holes such as 31, for corner strapping if necessary. Larger-sized sub-frames often need to be cross-braced at their corners to give extra rigidity and ensure squareness - the core holes 31 can receive self-tapping screws, for instance, for strapping the corners of a finished sub-frame.

Figures 10A and B show, in perspective view, additional components 36 and 37 which may be used to form part of a corner piece in accordance with the invention. A component such as 36 or 37 may be secured (by any suitable means) to an inside face of a basic corner piece such as that shown in Figure 8, so as to increase the size and alter the shape of the overall corner piece. Two or more such components may be used together, depending on the shape and size finally desired (which in turn depends on the profile of the strip material with which the corner piece is to be used). The two components 36 and 37 may be used together, arranged perpendicularly to one another and interlocking by means of peg 38 on component 37 and slot 39 in component 36, so as to form a corner joint.

The holes 40 are aligned with holes provided in the basic corner piece, via which the corner piece may if desired be secured to the lengths of strip material which it is used to join.

The additional components 36 and 37 greatly increase the versatility of the basic corner piece in use.

Practically speaking, the sizes and shapes of strip material from which sub-frames are constructed differ greatly from one to the next, depending on the structure in which any particular sub-frame is to be used. Often, the sides of a sub-frame must be made of a differently sized strip material to the top, and the bottom (which usually engages with a door or window sill in the finished structure) of a differently sized material again. This means that several different corner pieces are needed to allow all possible corner joints between differently sized pieces of strip material. Appropriate use of the two additional components allows several different corner joints to be formed, starting with just one size and shape of basic corner piece (as shown in Figure 8).

Alternatively, and still in accordance with the present invention, the basic corner pieces used may themselves differ in size and shape, depending on the profiles of the lengths of strip material with which they are to be used. Thus, any given sub-frame may well comprise a number of differently sized/shaped corner pieces.

Claims

1. A template sub-frame for use in defining a door or window aperture during the construction of a wall or similar structure, the sub-frame comprising two or more lengths of a strip material joined together at at least one of the corners of the sub-frame, the strip material having means by which it may be located in, and preferably secured to, the structure under construction, and the lengths of strip material being joined together at said at least one of the corners by means of a separate corner piece made of a suitable material, which corner piece is securable to the lengths of strip material.

2. A template sub-frame according to claim 1, wherein the corner piece is made from a plastics material.

3. A template sub-frame according to claim 2, wherein the corner piece is made from PVC-u.

4. A template sub-frame according to claim 2 or claim 3, wherein the corner piece is made from a recycled plastics material.

5. A template sub-frame according to any one of the preceding claims, wherein the corner piece is formed by extrusion.

6. A template sub-frame according to any one of claims 1-3, wherein the corner piece is formed by machining an existing PVC-u extrusion to the desired shape.

7. A template sub-frame according to any one of the preceding claims, wherein the lengths of strip material are made of metal.

8. A template sub-frame according to any one of claims 1-6, wherein the lengths of strip material are made of a plastics material.

9. A template sub-frame according to any one of the preceding claims, wherein the lengths of strip material have a box-like, or substantially box-like, cross section, which is at least partly hollow.

10. A template sub-frame according to claim 9, wherein the lengths of strip material have a C-shaped cross section.

11. A template sub-frame according to any one of the preceding claims, wherein the lengths of strip material have means for engaging a door or window frame which is inserted into the aperture defined by the sub-frame, once construction of the wall or other structure has been completed.

12. A template sub-frame according to any one of the preceding claims, wherein the corner piece comprises two separate components securable together to form the complete piece, each of which components may be secured to one of the lengths of strip material so as to join together the two lengths at a corner of the sub-frame.

13. A template sub-frame according to any one of the preceding claims, wherein the corner piece is adapted to be insertable into, and to fit firmly inside, substantially without movement, the strip material.

14. A template sub-frame according to claim 13, wherein one or more edges of the corner piece are chamfered, so as to provide a smoother lead-in when the corner piece is inserted into a length of the strip material.

15. A template sub-frame according to claim 13 or claim 14, wherein at least one of the lengths of strip material and/or the corner piece is provided with engaging means by which the strip material may engage with an inserted corner piece so as to hold it in its correct position in use.

16. A template sub-frame according to claim 15, wherein the engaging means takes the form of flaps or tangs provided at appropriate positions on the strip material.

17. A template sub-frame according to any one of the preceding claims, wherein the lengths of strip material and the corner piece are so shaped that edges of the strip material may be received in channels or slots provided in the corner piece, and the edges of the strip material and/or the inside walls of the channels or slots are appropriately profiled so as to engage positively with one another.

18. A template sub-frame according to any one of the preceding claims, wherein the lengths of strip material and the corner piece are provided with holes which, after assembly of the sub-frame, are aligned with one another so as to admit a fastening means, so as to secure the lengths of strip material and the corner piece together.

19. A template sub-frame according to any one of the preceding claims, wherein one or more of the lengths of strip material are crimped onto or into the corner piece.

20. A template sub-frame according to any one of the preceding claims, which is square or rectangular in shape.

21. A template sub-frame according to claim 20, which comprises a top and two sides, made from three lengths of strip material secured together by means of separate corner pieces, and a bottom made from a strip material having a different cross-sectional profile to that of the top and side pieces, in order to be securable to a door or window sill in the finished structure.

22. A template sub-frame substantially as herein described with reference to the accompanying illustrative drawings.

23. Use of a template sub-frame according to any one of the preceding claims, during the construction of a wall or similar structure, to define a door or window aperture.

24. A corner piece for use as part of a template subframe according to any one of claims 1-22.

25. A corner piece according to claim 24, which is made from a plastics material.

26. A corner piece according to claim 24 or claim 25, which comprises two separate components securable together to form the complete piece.

27. A corner piece according to any one of claims 2426, comprising an additional component which is securable to the corner piece so as to alter its overall size and shape.

28. A corner piece according to claim 27, wherein two or more additional components are used together, arranged perpendicularly to one another around the inside of the corner piece and interengaging with one another.

29. A corner piece substantially as herein described with reference to the accompanying illustrative drawings.

30. A component of a corner piece according to any one of claims 26-29, which component is separately securable to a length of strip material, and securable to another such component so as to form the complete corner piece.

31. An additional component for use as part of a corner piece according to any one of claims 27-29, the additional component being securable to the corner piece so as to alter its overall size and shape.

32. A component or additional component of a corner piece for use as part of a template sub-frame, the component being substantially as herein described with reference to the accompanying illustrative drawings.

33. Use of a corner piece according to any one of claims 24-29, or of a component according to any one of claims 30-32, in the assembly of a template subframe according to any one of claims 1-22.

34. Use according to claim 33, which takes place immediately prior to use of the sub-frame, at the site where the structure is to be constructed.