GB2437786A

GB2437786A - Reinforcement for window and door frames

Info

Publication number: GB2437786A
Application number: GB0608609A
Authority: GB
Inventors: Anthony Lee Hughes
Original assignee: Epwin Group PLC
Current assignee: Epwin Group PLC
Priority date: 2006-05-02
Filing date: 2006-05-02
Publication date: 2007-11-07
Anticipated expiration: 2026-05-02
Also published as: GB2437786B; GB0608609D0

Abstract

In order to manufacture a reinforced part of a window or door, a body (100) of thermoplastic material extruded to a length longer than the intended length of the part. A reinforcing insert (20) also of thermoplastic material is then inserted in the hollow interior (11) of the body (100) and secured to a wall of the body. The body (100) is then cut to the material length, with the reinforcement (20) occupying the full length of the cut body. Normally this is achieved by the cutting operation also cutting the reinforcement material. The reinforcement material may be extruded simultaneously with the body but is preferably inserted into the body separately.

Description

1 2437786

REINFORCEMENT FOR WINDOW MID DOOR STRUCTURES

This invention relates to a reinforced elongate part of a window or door structure, to a method of manufacturing the part, and to a method of manufacturing a reinforced window or door structure.

It is common in the construction industry for window and door frames to be manufactured by mitre cutting PVC-u and then fusion welding the resultant parts together using purpose designed machines. The body of material from which the window and door frames are made by a window manufacturer is usually supplied in lengths of six metres.

There is frequently a need to reinforce parts of such a window or door frame for two reasons: firstly, to add to the structural stiffness of the frame shell parts so they will become more able to sustain the loads that they will be subjected to in service and, secondly, to provide additional thickness for fasteners (for hinges, locks and the like) to penetrate. Generally steel or aluminium is used for the reinforcement material, though it is recognised that the reinforcement material must not corrode easily during the life of the window frame.

A known method for manufacturing a PVC-u window or door frame is to cut to length a body of PVC-u material to form a series of parts of a shell of the frame, to subsequently cut and fix metal reinforcement members to each part of the shell, and then to weld the shell parts together. The reinforcement members are commonly fixed to the shell parts using self drilling screws.

When a metal reinforcement member is originally cut, it has to be cut to a length which is slightly shorter than the PVC-u shell part to which it is to be fixed.

This is because, when the shell parts are being welded together, the surfaces that are being welded melt and so the lengths of the shell parts reduce slightly. However, the metal reinforcement members do not shrink during the welding. If the metal reinforcement members are not cut to this shorter length, then they would project from the ends of the shell parts where the weld is being performed, prevent the shell parts from contacting each other around the full path of the intended weld, and thus prevent a full weld being carried out at the join of the adjacent shell parts.

This known method of manufacture is time consuming because the PVC-u body material and the reinforcement members are individually cut to length. The appropriate length for a reinforcement member has to be first calculated based on the cut length of the shell part, the appropriate length being slightly shorter than the length of the shell part. If a reinforcement member for a shell part is cut too long then, as described above, an inadequate weld is formed between that shell part and an adjacent shell part, as the end surfaces of the shell parts will not be in contact along the full intended length of the weld. If the reinforcement member is cut too short then, once assembled, the frame would be allowed to flex and so the reinforcement of the window frame will be below optimal. Any inadequate joins would either need to be re-worked, or more likely the component parts would be scrapped. This leads to increased build times and wastage.

At its most general, the present invention proposes fixing a reinforcement material to an interior surface of a hollow body of material before the body is cut to length to form a shell of a part, and then subsequently cutting through the body to produce the shell with reinforcement material occupying the full length of the shell. This allows a reinforced part of a window or door structure to be manufactured more quickly and with less potential material waste than the known methods of manufacture.

The present invention has several aspects. Thus, according to the first aspect, the present invention provides a method of manufacturing a reinforced elongate part of a window or door structure, said part having an intended length in its elongate direction, said method comprising the steps of: extruding a thermoplastic material to form a body having a wall surrounding a hollow interior and having a length in the direction of extrusion greater than said intended length of the part; inserting a thermoplastic reinforcement material into the hollow interior of the body; securing the reinforcement material to the wall of the body; and then cutting through the body such as to shorten it in the direction of extrusion to said intended length, thus forming a shell of the part with the reinforcement material occupying the full length of the shell.

The structure may be all or part of a window or door frame or an opening part of a window or door within a frame. Where the structure is a window frame, then the reinforced part may be any or all of: a perimeter section, a sash section, a transom section (i.e. a horizontal frame element which divides the vertical height of a window), or a mullion section (i.e. a vertical frame element which separates adjacent window units) of the window frame. Where the structure is an opening part of a window, the part may be an opening sash section of the window or other part of the opening part of the window.

This process reduces the time taken to manufacture a reinforced part of a window or door structure as, firstly, only one cutting operation needs to be set up and performed in the overall process of manufacturing the reinforced part and, secondly, the length of the resultant reinforcement material does not have to be calculated prior to its formation; it automatically inherits the same length as the shell. In particular, a window manufacturer saves time and money by not having to cut and fit reinforcement members to shells of parts of window structures. He or she simply purchases lengths of material which already have reinforcement material fixed to them, and then cuts the lengths to the required dimensions for the part he wishes to make.

Although it is intended that the reinforcement material is inserted into the body after the body has been extruded, it is conceivable that the reinforcement material may be simultaneously extruded with the body.

The reinforcement material may be fixed to the body by a continuous join along the wall in the direction of extrusion of the body or alternatively it may be fixed at regular intervals along the wall. Thus, wherever the body is subsequently cut, the reinforcement material remains firmly fixed to the resultant shell of the part.

It is possible to imagine the situation where the reinforcement material does not need cutting with the body. It is possible that when the reinforcement material is fixed inside the body, it already has a length suitable for a part which will be made from the materials. Then when the body is cut to form a shell, the reinforcement material already has the correct length and does not need to be cut. However, normally the reinforcement material is cut with the body. As both the reinforcement material and the material of the shell is a thermoplastic, when they are cut together there is no contamination into either element by a foreign material.

If the reinforcement material was a metal, as reinforcement members of e.g. window frames often are, then the simultaneous cutting of both the shell and the reinforcement material would lead to metal filings being embedded in the shell of the part. This can reduce the effectiveness of any subsequent welding carried out on the reinforced part at an end which has been cut, and also impairs the appearance of the reinforced part.

Furthermore, as both the reinforcement material and the material of the shell of the part of the structure are thermoplastics, they will not corrode. Preferably the thermoplastic material of the shell is PVC-u.

Furthermore, it is preferable that the reinforcement material is PVC-u.

Preferably the reinforcement material occupies the full length of the body. Thus, this allows a subsequent cut to be performed at any point along the body to form a shell with reinforcement material occupying the full length of the shell.

According to a second aspect of the present invention there is provided a reinforced elongate part of a window or door structure, said part comprising: a shell made from a thermoplastic material, said shell having a wall surrounding a hollow interior; and a thermoplastic reinforcement material located in the hollow interior and secured to the wall of the shell, wherein said reinforcement material occupies the full length of the shell and is of the same length as the shell. The ends of the shell of the part are therefore * 7 flush (i.e. in the same plane) with the ends of the reinforcement material. Thus, both shells of such parts and the reinforcement material of such parts may be joined in a subsequent process of manufacturing a reinforced window or door structure, as described below.

According to a third aspect of the present invention there is provided a method of manufacturing a reinforced window or door structure, said method comprising the steps of: manufacturing a plurality of reinforced parts according to the method of the first aspect of the invention; and joining together said reinforced parts.

This method of manufacturing is quick to perform, due to the abovementioned advantages of the method of manufacturing the reinforced parts.

Preferably said reinforced parts are joined together both between the shells of the parts and between the reinforcement material of the parts. This enables a reinforced part of a window or door structure to be attached to another reinforced part over a larger surface area than known structures in which only the shells of the component parts are joined together, and so a very strong join can be produced between the two.

Preferably the reinforced parts are joined together by fusion welding. Because both the shells of the parts and the reinforcement members fixed to the shells are made from a thermoplastic, both will shorten during welding of the parts to each other.

An embodiment of the present invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which: Fig. 3. shows a cross section of a body of thermoplastic material for use in an embodiment of the method of the present invention; Fig. 2 shows a cross section of a thermoplastic reinforcement material for use in an embodiment of the method of the present invention; and Fig. 3 shows a cross section of a reinforced part of a frame made by an embodiment of the method of the present invention.

A method of manufacturing a perimeter section 30 of a window frame will now be described. By perimeter frame section 30 it is meant that part of a window frame which is positioned at the outer edge of a window of e.g. glass. Fig. 1 shows the cross section of a body 100 of thermoplastic material which will be used to form a shell of a perimeter section 30 of a window frame. This body 100 is made of PVC-u, has a length of six metres extending into the page and was formed by extruding the PVC-u. The body 100 has a wall 12 surrounding a hollow interior 11. The wall 12 and the hollow interior 11 extend along the full length of the body 100 in the direction of extrusion. The wall 12 has an internal surface 12a. * 9

Fig. 2 shows a cross section through a thermoplastic reinforcement material 20. The reinforcement material 20 has an outer surface 22 and has a length of e.g. six metres extending into the page. This thermoplastic reinforcement material 20 is also PVC-u.

The reinforcement material 20 is inserted into the hollow interior 11 of the body 100 and is then fixed at its outer surface 22 to the surface 12a of the wall 12 of the body 100. There are a series of joins between the reinforcement material 20 and the body 100 at regular intervals along the interface between these surfaces 12a, 22.

A subsequent step in the manufacture of the reinforced perimeter section 30 of a window frame is to cut through both the body 100 and the reinforcement material 20, thus forming a perimeter section 30 of required dimensions. This cut is made in the plane of the page, as Figs. 1 to 3 are drawn. Any splinters originating from the reinforcement material 20 during the cutting which become embedded in the resultant shell 10 will, of course, be of the same material as the shell 10 itself. Therefore the shell 10 does not become contaminated with foreign material, as would have been the case if the reinforcement material 20 had been of a different material e.g. a metal. The appearance of the cut shell 10 is thus preserved. Furthermore, the reinforcement material 20 remains fixed to the shell 10 along its full length after the body 100 and reinforcement material 20 have been cut.

Fig. 3 shows the resultant reinforced perimeter section 30 of a window frame manufactured by this embodiment of the present invention. This figure shows the reinforcement material 20 inside the shell 10 of the perimeter section 30 and also shows the join 40 between surfaces 12a, 22. The end 23 of the reinforcement material 20 projecting from the page (as Fig. 3 is drawn) is flush with the end 13 of the shell 10, i.e. the reinforcement material 20 does not project from the end 13 of the shell 10 which results from the cutting operation, and the shell 10 does not project from the end 23 of the reinforcement material 20 which results from the cutting operation.

An embodiment of the method of manufacturing a reinforced window or door structure will now be described. The structure is a window frame.

The first step is to manufacture the reinforced parts required for the frame (not shown) . In this embodiment, just four perimeter frame sections 30 are required, one for each of the four sides of a rectangular window frame. These perimeter sections 30 are each manufactured as described above. Each perimeter section 30 has its ends cut at 45 such that, when the sections are brought together to form a rectangular frame, each corner of the frame will comprise the cut ends of two sections 30 meeting to create a 90 angle in the frame.

At each cut end of the perimeter sections 30 the end 23 of the reinforcement member 20 is flush with the end 13 of the shell 10, i.e. end 23 is on the same plane as end 13.

Subsequently, the perimeter sections 30 are fusion welded together at their 45 -cut ends to form the rectangular frame. It will be appreciated that, during the fusion welding, both the shell 10 of each perimeter section 30 and the reinforcement material 20 fixed inside each shell 10 heats up and shortens in length. This is different to conventional manufacturing methods where metal reinforcement members remain the same length during welding of adjacent shells of perimeter sections. Thus, with the method of the present invention, no part of a reinforcement material 20 extends beyond the length of a shell 10 during welding, and so a full weld can be carried out at the interface of one perimeter section 30 with an adjacent perimeter section 30. The shell 10 of one perimeter section 30 becomes joined to the shell 10 of an adjacent perimeter section 30, and the reinforcement material 20 of the two sections 30 also becomes joined. Thus a strong join is formed between the perimeter sections 30.

Of course, not all of the required perimeter sections 30 for the window frame would need to be manufactured before the welding is begun. For example, in the described embodiment, welding could have been carried out between two perimeter sections 30 while the * 12 other two perimeter sections 30 required for the frame were being manufactured.

The resultant window frame is strongly welded at each join between component parts and has reinforcement material securely fixed around the full perimeter of the frame.

It will thus be appreciated that the method of the present invention allows a reinforced part for a window or door structure to be manufactured quickly, without the need to calculate the required length of reinforcement material to be fixed to a shell of the part of the structure. Furthermore, when such parts are joined together to create a reinforced structure such as a window frame, a strong join can be created without fear of a portion of the reinforcement material protruding from the shell of one part preventing a surface of the part being joined to the surface of another part. The resultant structure has component parts firmly fixed together, as well as reinforcement material firmly fixed to the shell parts.

Claims

CLAIMS: 1. A method of manufacturing a reinforced elongate part of a

window or door structure, said part having an intended length in its elongate direction, said method comprising the steps of: extruding a thermoplastic material to form a body having a wall surrounding a hollow interior and having a length in the direction of extrusion greater than said intended length of the part; inserting a thermoplastic reinforcement material into the hollow interior of the body; securing the reinforcement material to the wall of the body; and then cutting through the body such as to shorten it in the direction of extrusion to said intended length, thus forming a shell of the part with the reinforcement material occupying the full length of the shell.

2. A method according to claim 1, wherein the reinforcement material is simultaneously cut with the body.

3. A method according to claim 2, wherein the thermoplastic reinforcement material occupies the full length of the body.

4. A method according to any one of the preceding claims, wherein the material of the body is PVC-u.

5. A method according to any one of the preceding claims, wherein the reinforcement material is PVC-u.

6. A method according to any one of the preceding claims, wherein said structure is a window frame.

7. A method according to claim 6, wherein said reinforced part is one of a perimeter section, sash section, transom section or mullion section of the window frame.

8. A method according to any one of claims 1 to 5, wherein said structure is a door frame.

9. A reinforced elongate part of a window or door structure, said part comprising: a shell made from a thermoplastic material, said shell having a wall surrounding a hollow interior; and a thermoplastic reinforcement material located in the hollow interior and secured to the wall of the shell, wherein said reinforcement material occupies the full length of the shell and is of the same length as the shell.

10. A method of manufacturing a reinforced window or door structure, said method comprising the steps of: manufacturing a plurality of reinforced parts according to the method in any one of claims 1 to 8; and joining together said reinforced parts.

11. A method according to claim 10, wherein said reinforced parts are joined together both between the shells of the parts and between the reinforcement material of the parts.

12. A method according to claim 10 or claim 11, wherein the reinforced parts are joined together by fusion welding.

13. A method of manufacturing a reinforced part of a window structure substantially as described herein with reference to and as illustrated in the accompanying drawings.