GB2459117A

GB2459117A - Lug for window frame assembly

Info

Publication number: GB2459117A
Application number: GB0806515A
Authority: GB
Inventors: Ramon Rabett
Original assignee: DUCHY INVEST Ltd
Current assignee: DUCHY INVEST Ltd
Priority date: 2008-04-10
Filing date: 2008-04-10
Publication date: 2009-10-14
Anticipated expiration: 2028-04-10
Also published as: GB0806515D0; GB2459117B

Abstract

A lug 24 for connecting a pre-fabricated window frame 15 into a wall opening 11 having smaller external dimensions than internal dimensions and the internal opening having a pocket liner 14 fitted to the internal reveal 12 thereof. The lug has a first part 26 for connection to the frame and a second part 27 for connection to a face of the pocket liner 14. The lug also has a mounting flank 25 extending between the first and second parts and which in use lies substantially parallel to the adjacent reveal of the opening. In use a jamb liner 32 for carrying an architrave 34 is securable to the mounting flank at suitable position. When the window frame is fitted to the opening and is secured in position by the second parts of a plurality of lugs 24 and an architrave is secured to the jamb liner, the architrave lies chosen surface associated with the internal face of the wall. The present invention also provides a window assembly and assembly method incorporating such lugs.

Description

FITTING REPLACEMENT WINDOWS

This invention relates to the fltting of a window to an existing window opening in a walL In particular, but not exclusively, the invention relates to the fitting of a replacement sash window to an opening in a wa which previously had fitted thereto a conventional sash window including counterweights for the sliding paneL In its preferred aspects, this invention concerns a lug for use in connecting a prefabricated frame to a window opening, a window assembly including a frame and a pIuraity of such lugs and a method of fitting a prefabricated window frame to an existing window opening.

A conventional sash window has a pair of counterweights connected to ic the s'iding panel by cords which run over pulleys at the top of the frame, the counterweights being disposed within timber boxes one to each side of the frame. In order to allow sufficient space for the accommodation of the boxes, the window reveal is stepped such that the internal dimensions of the reveal are greater than the external dimensions. Such a reveal configuration s often is referred to as a check reveal having a reverse brick detail such that there is a cheek against which the frame of the window abuts, from the inside.

When a conventional sash window fitted within a check reveal is removed for replacement by a prefabricated sash window, usually of aluminium but possibly of plastics materials, the space within the check reveal is no onger required since such replacement windows do not normally employ counterweights and so on for balancing the weight of the sliding panel. The usual practice is to fit within that space a so-called pocket liner of timber, to extend along the sides of the reveal and to which the replacement frame can be secured.

A particular problem arises in the case of a replacement sash window to be fitted within a window opening which previously accommodated a wooden sash window, in that there is a significant gap between the outer edge of the replacement frame and the reveaL This gap is normally covered by an architrave but if that is cantilevered from the wafl, it may give rise to an unsightly gap between the architrave and the frame and further the architrave is prone to damage in view of the relatively large unsupported width thereof.

io This invention aims at addressing the above problem of fitting a replacement sash window into a window opening which previously had a conventional wooden sash window fitted therein.

According to a first aspect of this invention, there is provided a lug for connecting a pre-fabricated window frame into a wall opening having smaller external dimensions than internal dimensions, the internal opening having a pocket liner fitted to the sides thereof, said lug having a first part for connecting to the frame and a second part for connecting to a face of the pocket liner, the lug having a mounting flank extending between the first and second parts and which when in use lies substantially parallel to the adjacent side edge of the opening, whereby when in use a jamb liner for carrying an architrave is securable to the mounting flank at a suitable selected position so that when the window frame is fitted to the opening and is secured in position by the second parts of the lugs and an architrave is secured to the jamb liner, the architrave lies against the internal face of the wall.

It wiH be appreciated that when using the lug of this invention as described above, it becomes possible to support the inner edge of an architrave so as better to close the gap between the replacement frame and the reveal.

This gives rise to a particularly neat construction for a replacement window and moreover the arrangement makes the architrave much less likely to be damaged or broken since it is no longer cantilevered from the wall.

According to a second but closely related aspect of this invention there is provided a window assembly for fitting into a wall opening having smaller external dimensions than internal dimensions and a pocket liner fitted to the io reveal of the internal opening, which assembly comprises a prefabricated window frame and a plurality of tugs for securing the frame in the required position within the opening, each lug having a first part connected to the frame and a second part for connecting to a face of the pocket liner, the lug further having a mounting flank extending between the first and second parts and is which lies substantially parallel to but spaced from the adjacent side edge of the frame so as to define in conjunction therewith a slot, whereby in use a jamb liner for carrying an architrave is receivable in said slot and is securable to the mounting flank at a suitable selected position so that when the window frame is fitted to the opening and is secured in position by the second parts of the lugs and an architrave is secured to the jamb liner, the architrave lies against a chosen surface associated with the internal face of the wall.

With this second aspect of the invention, a plurality of lugs are positioned around the frame of the replacement window at a suitable spacing in order to allow secure fixing of the window to the pocket liner pre-mounted within the check reveal of the window opening. The provision of the lugs permits the use of a jamb liner to support the inner edge of an architrave secured to the wall around the window opening thereby to bridge the gap between the wall and the replacement frame.

According to a third aspect of this invention, there is provided a method of fitting a prefabricated window frame to a wall opening having smal'er external dimensions than internal dimensions, comprising the steps of: -fitting a pocket liner to the reveal of the interna' opening; -attaching a first part of each of a plurality of a lug to the frame, each io lug having a second part for connecting to a face of the pocket liner and a mounting flank extending between the first and second parts and which lies substantially paralle' to but spaced from the adjacent side edge of the frame so as to define in conjunction therewith a slot; -fitting a jamb liner into the slot such that an edge thereof is is substantially cop'anar with a chosen surface associated with the internal face of the wall when the frame is secured within the opening; -securing the jamb liner in position to the mounting flank; -attaching the second parts of the lugs to said face of the pocket liner to secure the frame in the opening; and -attaching an architrave to said edge of the pocket liner so as to bear on said chosen surface associated with the internal face of the wall.

In view of the fact that the jamb liner may adjustably be positioned in the slot between the mounting flank of the lug and the outer frame member, it is possible to accommodate different depths of reveal merely by adjusting the position of the jamb liner within the slot such that the outer edge of the jamb liner is substantiay coplanar with the internal surface of the waU. In the event that the reveal is relative'y shaow, it is stifi possible to use the same arrangement but then it may be necessary to mount a strip, for example of timber, along the edge of the window opening such that the architrave is carried by that strip and the jamb liner and so is spaced inwardly of a room from the interna' wa surface.

By way of examp'e only, one specific embodiment of this invention will now be described in detail but in three different arrangements by way of io illustration, reference being made to the accompanying drawings in which:-Figure 1 is a scrap cross-sectional view through a wall having a window opening into which is fitted a sash window frame, using a plurality of lugs of this invention and in accordance with a method also of this invention; Figure 2 is a view similar to Figure 1 but showing an alternative is arrangement where the revea' of the window opening is relatively deep; and Figure 3 is a view similar to Figure 1 but showing another arrangement where the reveal of the window opening is relatively shallow.

Referring initiaUy to Figure 1, there is shown a wall 10 having a window opening 11 which is defined by an internal reveal 12 and a check reveal 13 (otherwise known as a reverse brick detail) such that the external dimensions of the wall opening are smaller than the internal dimensions. Such a wall opening with a reverse brick detail is commonly employed with conventiona' wooden sash windows in order to allow space for the accommodation of weights, pulleys and cords to counterbalance the weight of the sliding panel of the window. When such a sash window is to be replaced by modern aluminium-framed windows, there is in general no need to provide counterbalancing weights such as was conventional'y employed and consequently there is a pocket behind the reverse brick detail which is no longer required. t is the usual practice to secure a pocket iner, usually of timber, within that pocket, so that the replacement window may be attached to the pocket liner.

n Figure I, the pocket liner is shown at 14 and is secured to the internal reveal 12 so as to extend therealong. The sash window frame 15 is prefabricated from aluminium sections which are known per Se, using io conventional manufacturing techniques. Since that window frame and the sections from which it is made form no part of the inventive concept of this application, they will not be described in further detail here other than to indicate that the outer frame member 16 defines a pair of channels 17 extending therealong, each channel having opposed inwardly directed flanges is 18.

When the replacement window is fitted to the window opening, it should be positioned such that the external face 19 of the outer frame member 16 engages against the inwardly directed face of the check reveal 13, as shown at 20. When so positioned, there is a variable spacing between the internal face 21 of the outer frame member 16 and the internal walt surface 22, depending upon the depth of the internal reveal 12, as determined from the internal wall surface 22 to the check revea' 13.

n this embodiment, the frame is secured in position within the internal reveal 12 by means of a plura'ity of lugs 24 arranged a'ong both sides of the outer frame member 16 and typicaUy also across the head of the frame. Each lug is formed from metal and has a width of about 20mm; the lugs should be positioned around the frame at not more than 600mm centres, with the lugs nearest the corners of the frame being positioned not more than a predefined distance from the corners.

Each lug 24 has a central mounting flank 25 provided at one end with a first part 26 adapted for connection to a channel 17 of the outer frame member 16 and at the other end with a second part 27 extending at right angles to the mounting flank and adapted for connection to the pocket liner 14. The first part 26 has a substantially linear first section 28 extending at right angles to the mounting flank 25 and a second section 29 extending at right angles to the first section, so as to lie substantially parallel to but spaced from the mounting flank 25. The second section 29 terminates in an arm 30 turned back towards the mounting flank 25. Adjacent the junction between the first and second sections 28,29 of the first part 26, there are two second arms 31, one on each side of the lug and each cut from the material thereof, which second arms are deformed outwardly from the remainder of the first section 28. In this way, the second section 29 of the first part of the lug may be snap-fitted into the channel 17 with the arms 30,3 1 engaging behind the inwardly directed flanges 18 of the channel, thereby securely holding the lug to the outer frame member 16.

When the lugs have been fitted as described, a slot is formed between the mounting flank 25 of each lug 24 and the inwardly directed flanges 18 of the two channels 17 formed along the length of the outer frame member 16. A timber jamb liner 32 is located in that slot to extend along the length of the frame member 16, the position of that jamb ner 32 relative to the outer frame member 16 being adjustable to suit the depth of the reveal 12. The objective should be to have the outer edge 33 of the jamb liner 32 essentiay coplanar with the internal wa surface 22 as shown in Figure 1, such that subsequent to fitting of the window to the opening, an architrave 34 may be attached to both the jamb liner and the wafl, to extend over the gap between the frame member 16 and the walL The window frame is fitted to the window opening in the foowing manner. The pocket liner 14 is attached to the internal reveal 12 using suitable io fastenings such that face 36 of the pocket liner is at a pre-set distance from the check reveal 1 3 of the window opening. A plurality of lugs 24 are attached to the outer frame member 16 as has been described above, by interengagement of the second section 29 of each ug with the channel 17, with the appropriate spacing between the lugs. The window frame is then offered to the opening is such that the external face 19 of the outer frame member 16 abuts the check reveal; when so positioned, the second part 27 of the lug 24 should more or less engage face 36 of the pocket liner 14, depending upon the building tolerances.

The jamb liner 32 is pressed into the slot between the mounting flank 25 and the channels 17 and its position is adjusted until the outer edge 33 of the jamb liner is substantially coplanar with the internal wall surface 22. At each ug a line is then drawn on the jamb liner 32, at the junction between the central mounting flank 25 and the second part 27 thereof. The frame is then removed from the window opening and the jamb liner is secured to the mounting flanks by means of screws passing through holes in the mounting flanks on the centres 37, with the liner positioned appropriately in accordance with the lines drawn thereon.

The window frame is then fitted once more into the opening and is secured in position by means of further screws passing through holes in the second section 29 of each lug 24, on the centres 38 also shown on Figure 1.

When completed, the outer edge 33 of the jamb liner 32 should be essentially coplanar with the internal wall surface 22 such that an architrave 34 may be secured to the jamb liner 32 and to the internal wall surface 22, also as shown io in Figure 1.

Figure 2 shows an arrangement which is similar to that of Figure 1 described above except that the reveal is relatively deep. Like parts with those of Figure 1 are given like reference characters and will not be described again here.

is When fitting the window frame to a relatively deep reveal, the pocket liner 14 is secured to the internal reveal 12 such that the distance between face 36 of that liner and the check reveal 13 is the same as with Figure 1; the face 36 is thus disposed deeper within the reveal than is shown in Figure 1 Despite this, when the frame is offered into the opening and engages the check reveal 13, the second part 27 of each lug 24 still engages the face 36 of the pocket liner, as previously.

When the window is positioned as shown, the jamb liner 32 is again positioned such that its outer edge 33 is substantially coplanar with the internal wall surface 22; the liner 32 is thus less deeply inserted into the slot than is the case with the arrangement of Figure 1. FoUowing marking of the jamb ner, the frame is removed from the opening and the jamb liner 32 is secured to the mounting flank 25 as previously, but so as to project beyond the internal face 21 of the frame member 16, as shown. Foowing mounting of the frame in the opening, by securing the second parts 27 of the lugs 24 to the pocket liner 14, the architrave 34 may be attached to both the wall surface and the jamb liner, again as has been described above.

The arrangement shown in Figure 3 differs from those described above in that the reveal is relatively shallow and thus face 36 of the pocket liner 14 is io disposed relatively close to the internal wall surface 22. In order to address this issue, a timber ground strip 40 is attached to the internal wall surface to extend parallel to the edge of the reveal 12, such that the architrave 34 will be stepped inwardly with respect to the internal wall surface. The jamb liner 32 is secured to the mounting flank 25 such that the outer edge 33 of the jamb liner is is substantially coplanar with the exposed face of the timber ground strip 40 and the architrave then bridges between the jamb liner and the ground strip, as shown in Figure 3. In all other respects, the arrangement of Figure 3 corresponds to those described above, including the method of fitting the window.