GB2565608B

GB2565608B - Window frame member

Info

Publication number: GB2565608B
Application number: GB1720896.8A
Authority: GB
Inventors: Gregory Philip
Original assignee: Veka PLC
Current assignee: Veka PLC
Priority date: 2017-12-14
Filing date: 2017-12-14
Publication date: 2019-08-28
Anticipated expiration: 2037-12-14
Also published as: GB201720896D0; GB2565608A

Description

WINDOW FRAME MEMBER

The present invention relates to sliding sash windows, and to frame members for sliding sash windows.

The general construction of sliding sash windows will be very familiar to the skilled person. Typically a pair of sashes (glazed panels) is carried in an outer window frame. One or both of the sashes is (are) slidable with respect to the window frame to enable the window to open. In the case of a vertical slider sash window, the upright members of the window frame provide mounting channels which serve (a) to slidably mount the sashes themselves and (b) to receive a balance mechanism which at least partially supports the weight of the sash and may also damp its movement, helping the user to raise the sash and preventing it from falling under its own weight.

Traditionally the window frame and the structures of the sashes were made of timber. In the modern world they are often made from members comprising plastics, very often poly vinyl chloride ("PVC"), or metal, typically aluminium. A PVC window frame part may incorporate a stiffening member made of metal to reduce any tendency for it to distort in use.

The outer window frame needs to be secured in an opening in a wall, to mount the whole window assembly. Often this is done using screws or similar fastenings which are passed through the members making up the frame into the surrounding wall. The upright window frame members of a vertical slider window are typically secured by screws passed through holes in the mounting channels that receive the sashes. This is advantageous in that the screw heads are visually inconspicuous, being concealed by the sashes (at least while the window is closed) and/or by the balance mechanisms. But there are three disadvantages with this mode of mounting: i. swarf created by drilling into the surrounding wall structure can collect in the mounting channel and, if not removed (which is often the case) can enter the balance mechanism and impair its function; ii. some of the screw heads may be visible when the window is opened; and iii. the screw heads bear upon the PVC with little distribution of their loading, which may cause local stress and distortion.

In accordance with a first aspect of the present invention there is an elongate window frame member for a sliding sash window, comprising: a first mounting channel configured to slidably receive an edge of a first sash; a second mounting channel laterally offset from the first mounting channel and configured to receive an edge of a second sash; a longitudinally extending stiffener cavity containing an elongate stiffening member; a longitudinally extending installation channel which is adjacent the stiffener cavity and between the first and second mounting channels; the frame member further comprising a separately formed elongate installation cover mountable over the installation channel, so that the frame member is mountable to a wall by forming holes through the installation channel and through a stiffening member in the stiffener cavity and passing fasteners through respective holes to engage with the wall, after which the installation cover is able to be fitted conceal the fasteners.

Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:-

Figure 1 is a cross section through a window frame member embodying the present invention seated on surrounding brickwork;

Figure 2 is a perspective view of the same frame member, viewed from one end, and additionally shows separately formed installation covers;

Figure 3 is a view of the same frame member from above and to one side; and

Figure 4 shows a sliding sash window.

The window frame member 10 depicted in the drawings is for use in a vertical slider, double hung sash window 12 of the type depicted in Figure 4, forming one of the uprights of the window's outer frame 16 which is secured in an opening in an exterior wall (not shown) and which serves to carry and mount two glazed sashes 18, 20, each of which is able to slide up and down to open and close the window. The frame member 10 comprises plastics in the present embodiment. More specifically, it is extruded in one piece from un-plasticised PVC. Recycled PVC is suitable.

The frame member 10 has an exterior face 22, which is to the left in Figures 1 and 2 and which is directed toward the exterior of the building when the window frame is mounted, and an interior face 24 which is to the right in Figures 1 and 2 and which is directed toward the interior when the window frame is mounted. It has a base wall 26 which lies in use adjacent the brickwork 28 to which the frame member 10 is mounted, but is separated from it by a plurality of feet 30 which depend from the base wall 26 and extend along its length, the feet each having a respective mushroom head 32 to seat upon the brickwork 28. Note that although "brickwork" is referred to in this context, the window frame may be mounted in any suitable wall, whatever its construction.

The frame member 10 has a somewhat complex hollow form designed to provide a robust member while minimising the volume of material used. Its exterior face 22 is formed on a box section part 34 carrying an upstand 36 having an inwardly facing seal-receiving channel 38 for mounting a weather seal (which is not depicted, but can be an elastomeric seal of a type well known to the skilled person) which acts - in the assembled window - against an outer face of one of the sashes 18 to resist ingress of water. Adjacent and inboard of the box section part 34 is a first mounting channel 42 which serves two functions: it slidably engages with an edge of sash 18 to mount the sash. For this purpose it has at its mouth an opposed pair of sub-channels 44, 46 which engage with suitable formations on the sash 18 (whose form is well known and will not be described herein); it receives a balance mechanism acting on the sash 18. The balance mechanism is not depicted herein but is an elongate arrangement which resides in a lower region 48 of the first mounting channel 42. Suitable balance mechanisms are well known in the art. A stiffener cavity 50 is provided, lying in the present embodiment partly beneath and partly to the inner side of the first mounting channel 42. The stiffener cavity 50 receives an elongate stiffening member 52 which resists bending of the frame member 10. In the present embodiment the stiffening member 52 is a hollow metal member, more specifically a steel box section.

In accordance with the present invention, the frame member 10 provides an installation channel 54 above the stiffener cavity 50. The installation channel 54 is open towards the sashes 18, 20 (i.e. it is open in the upward direction, in Figures 1 and 2) and has a bottom wall 56, side walls 58 and an opposed pair of engagement lips 60. The bottom wall 56 lies against the stiffening member 52.

To fasten the frame member 10 to the brickwork 28, holes can be formed through the bottom wall 56 of the installation channel 54, the stiffening member 52, and the frame member's base wall 26 and into the brickwork 28 itself. Each hole receives a fastener 62 secured in the brickwork 28 and having an enlarged head 64 to engage the bottom wall 56 of the installation cavity. The fastener 62 is a threaded screw in the present embodiment. It may be screwed directly into the brickwork 28 or may be received in some form of wall plug in the brickwork 28.

Because the fastener 62 passes through the stiffening member 52, its loading is borne and distributed by the stiffening member, providing a secure fixing and minimising any tendency for the frame member 10 to be undesirably distorted. The holes in the frame member 10 and the stiffening member 52 which receive the fastener 62 may be pre-formed during manufacture, or may be drilled during installation of the window frame. The holes in the brickwork 28 will typically be drilled, or at least begun, with the frame in situ to ensure correct positioning of the holes. Note that any swarf produced does not fall in the mounting channel 42 where it might impair the function of the balance mechanism.

An installation cover 70 or 72 is fitted over the installation channel 54, serving two functions. It covers the installation channel and so conceals the heads of the fasteners 62, providing a clean appearance. It can also carry a weather seal to act against the outer face of the second sash 20. The installation cover 70, 72 has a cover wall 76 with two depending resilient limbs 78 shaped to be inserted into the installation channel 54 and to engage with the engagement lips 60 in a "snap fit" manner. That is, the limbs 78 are deformed elastically as they are inserted and then snap back to engage the lips 60 and so retain the installation cover 70, 72 in position upon the installation channel 54.

Note that Figure 2 shows two different versions of the installation cover 70. One version 70 has a weather seal-receiving channel 80 for mounting a weather seal seen at 82 in Figure 3 on an inwardly directed face of an upstand 84. The other version 72 of the installation cover has no weather seal, the inwardly directed face of the upstand 84 being plain. In both versions the upstand 84 has on its outwardly directed face an abutment strip 86 which abuts an adjacent face 88 of the first mounting channel 42, which has two functions. It provides a flat outer face and hence a clean appearance, but in the version 70 having the weather seal it also reacts force applied through the seal to the face 88, so that the mounting 60, 78 of the installation cover 70/72 does not need to carry this force.

On the inner side of the installation channel 54 is a second mounting channel 90, similarly formed to the first mounting channel 42 and serving, in the assembled window, to slidably mount the second sash 20.

Looking now at Figure 3, a complete frame member carries both the first and second versions 70, 72 of the installation cover, the first version with the weather seal 82 being below the other so that the weather seal 80 engages the second sash 20 when it is in the closed position.

Claims

1. An elongate window frame member for a sliding sash window, comprising: a first mounting channel configured to slidably receive an edge of a first sash; a second mounting channel laterally offset from the first mounting channel and configured to receive an edge of a second sash; a longitudinally extending stiffener cavity containing an elongate stiffening member; a longitudinally extending installation channel which is adjacent the stiffener cavity and between the first and second mounting channels; the frame member further comprising a separately formed elongate installation cover mountable over the installation channel, so that the frame member is mountable to a wall by forming holes through the installation channel and through a stiffening member in the stiffener cavity and passing fasteners through respective holes to engage with the wall, after which the installation cover is able to be fitted conceal the fasteners.

2. An elongate window frame member as claimed in claim 1 in which the installation cover carries a seal engageable in use with the second sash.

3. An elongate window frame member as claimed in claim 2 in which the installation cover has a laterally projecting abutment extending away from the said seal which serves to react force applied in use to said seal.

4. An elongate window frame member as claimed in claim 1 in which the installation cover is in two parts, one of which carries a seal and one of which does not.

5. An elongate window frame member as claimed in any preceding claim in which the installation covers comprises a pair of limbs configured to snap fit in the installation channel.

6. A sliding sash window comprising a frame member as claimed in any preceding claim.

7. A method of mounting a frame for sliding sash window to a building, comprising providing the frame with a frame member comprising a first mounting channel configured to slidably receive an edge of a first sash; a second mounting channel laterally offset from the first mounting channel and configured to slidably receive an edge of a second sash; a longitudinally extending stiffener cavity for containing an elongate stiffening member; an elongate installation channel which is adjacent the stiffener cavity and between the first and second mounting channels; the method further comprising forming holes through the installation channel and the stiffening member and into the wall; passing fasteners through respective holes to engage with the wall; and applying an installation cover over the installation channel, thereby concealing the fasteners.