GB2286454A - Window frame trickle ventilation - Google Patents

Abstract

A trickle ventilation system has a ventilation passage (44, 29a, 29b) formed through a hollow profile frame member of a vent window frame (25). The flow of outside air into the passage is through a vent (35, 36) in a glazing bead (30) engageable with the frame member and serving to retain a glazing panel (38) in the window frame. <IMAGE>

Description

TRICKLE VENTILATION SYSTEMS Hollow profile sections, particularly extruded uPVC (unplasticised polyvinyl chloride) profiles, are increasingly being used as structural members for door and window frames.

These hollow profile sections are structurally strong and provide good thermal insulation. In addition, the hollow profile section at the head (top) of a vent window frame has been used to provide trickle ventilation by forming a ventilation passage through the profile from the inside wall to the outside wall.

However, the present system of trickle ventilation requires an external vent cover which protrudes from the outside wall of the profile. This is not only unsightly but inevitably adds to the manufacturing costs.

According to one aspect of the present invention, an external vent for a trickle ventilation system is provided in one of the inwardly facing walls bounding the opening of a glazed window frame. The external vent is preferably covered, and the cover preferably comprises a vented glazing bead engageable with the inwardly facing wall and additionally serving to retain a glazing panel in the opening of the window frame.

According to a second aspect of the present invention, a trickle ventilation system having a ventilation passage formed through a hollow window frame member is characterised in that the air flow into the passage is through a vent in a glazing bead engageable with the frame member and serving to retain a glazing panel in the window frame.

The ventilation passage is preferably formed in the top member of the window frame such that the vented glazing bead engages an inwardly and downwardly facing surface of the frame.

In a preferred embodiment of the invention, the glazing bead is formed in two parts. A first moulded part contains the vent and is releasably engageable with the second part which is an extrusion. The extrusion may then extend the full width of the opening while the moulded part of the bead may be split into shorter lengths to reduce manufacturing costs.

In the accompanying drawings, by way of example only: Fig. 1 diagrammatically illustrates a prior art procedure for beading a glazed window frame; Fig. 2 shows a typical frame profile section being fitted with a prior art glazing bead; Fig. 3 shows the frame profile of Fig. 2 with the glazing bead fitted; Fig. 4 shows a prior art trickle ventilation system; Fig. 5 is a cross-section through a window frame fitted with a trickle ventilation system embodying the invention; Fig. 6 is a perspective view of the venting system shown in Fig. 5; and Fig. 7 is a perspective view of the vented glazing bead used in the venting system of Figs. 5 and 6.

Referring first to Figs. 1-3, a conventional vent window frame 10 having extruded hollow profile uPVC frame members is fitted with glazing beads 11, 12, 13 and 14. The top and bottom beads 11, 13 are butt cut and fitted before the mitred vertical beads 12, 14 are fitted.

The extruded profile section for each hollow frame member is generally rectangular with a network of internal walls providing multiple internal chambers. In this specification, the opposed external walls of the profile which respectively face inside and outside the building or room in which the window is fitted will be referred to as the inside and outside walls of the profile, respectively, while the external walls of the profile which face into the opening formed by the window frame will be referred to as the inwardly facing walls.

Figs. 2 and 3 show the beading procedure for a typical profile section.

It can be seen that the inside wall 15 of the profile is extended to provide a flange 17 against which the glazing panel (not shown) is abutted when a glazing bead 18 is fitted to the inwardly facing wall 40 of the profile.

The glazing bead 18 is fitted in a groove 20 of the wall 40 using a "shuffle" method in which a tongue 19a projecting from the bottom wall of the glazing bead 18 is first located in groove 20a, and a tongue 19b is subsequently located in groove 20b by displacing the bead 18 to the right (as viewed in Fig. 3) when the glazing panel is wedged into place. The glazing bead 18 includes co-extruded flexible lips 21 which resiliently retain the glazing panel in position against the flange 17.

Referring next to Fig. 4, in which like reference numerals used in Figs. 1-3 are used to denote like parts, the profile frame member of Figs. 2 and 3 is shown inverted and without the glazing bead, but fitted with a known trickle ventilation system. The ventilation system includes an internal trickle vent 21 and an external cover vent 22, both vents being push-fitted into routered slots respectively formed in the inside and outside walls 15, 16 of the profile. Only the slots 23 in the inner wall 15 are visible in Fig. 4. The external cover vent 22 consists of a cover housing 41 with ventilation openings 24 communicating with the slots (not shown) in wall 16 to provide a flow of air through the profile frame member.

An embodiment of the invention is then illustrated in Figs. 5-7. A vent frame 25 which opens and closes against a fixed outer frame 26 is formed of extruded uPVC hollow profile sections identical to those shown in Figs. 1-4, and like parts are again denoted by like reference numerals.

A standard internal trickle vent cover moulding 21 is fitted to the inside wall 15 of one of the profile sections forming the top of the vent frame 25. The vent 21 communicates with a slot 44 in the wall 15 and with routered slots 29a, 29b formed respectively in an internal wall 45 and in the inwardly and downwardly facing external wall 40 of the profile section. The slots 44, 29a and 29b provide a ventilation passage through the profile section. The slot 44 extends the full length of the cover moulding 21 but is sub-divided into sections by transverse strips of solid profile.

The downwardly facing external wall 40 of the profile section is engaged with a two-part glazing bead 30 which is separately illustrated in Fig. 7.

The first part of bead 30 consists of an injection moulding 31 having a top wall 32, a side wall 47, and a bottom wall 48. The top wall 32 has elongate slots 35 aligned with the routered slots 29 in the wall 40 of the profile section, and also aligned with corresponding ventilation slots 36 in the bottom wall 48 of the bead moulding. The side wall 47 has a projecting tongue 33 engaged in the groove 20a in the wall 40 of the profile section.

The second part of the glazing bead 30 is an extruded section 54. The injection moulding 31 is open along one side but the top and bottom walls 32, 48 have respective tongues 49, 50 slidably engageable with respective slots formed in top and bottom cantilevered portions 51, 52 of the extruded section 54. The section 54 therefore closes the open side of the injection moulding 31. The top cantilevered portion 51 of the extruded section 54 also includes a tongue 53 which slidably engages the corresponding groove 20b in the external wall 40 of the profile section.

The bead unit 30 therefore serves the dual function of a vented cover for the external vent 29b in the profile, and a glazing bead for retaining the glazing panel 38 (Fig. 5) against the flange 17 of the inside wall 15 of the profile section. The airflow through the bead is shown by the arrow head in Fig. 6, and the glazing panel is retained in place using conventional sealing gaskets 39 shown in Fig. 5.

There are a number of advantages in forming the glazing bead in two parts. Firstly, the injection moulding 31 can be made from short standard lengths which are easy to mould and commensurate with a standard window opening. For example, with a 600mm window frame having an opening of 480mm, two short lengths of 240mm can be used. Should there be a requirement for a non-standard length, extra short pieces can be cut and inserted along with one or more of the standard length pieces. The extruded section 54, on the other hand, can be easily cut to any required length and will extend the full width of the window frame opening in each case. Accordingly, any joins between the short moulded sections will be concealed.

An added advantage of having the separate extruded section 54 is that, where another size or type of glazing unit is to be used with the system, it would be necessary only to change the design of the injection moulding 31, not the extruded section.

Furthermore, the extruded section 54 also acts as a weather bar to deflect water flow away from the face of the unit.

The illustrated vented bead system can provide more than the required ventilation to comply with Building Standards and it can achieve this without the need for additional vents on the outside wall of the vent frame. With the prior art system of Fig. 4, the maximum amount of ventilation was restricted by the size of the slots 23. By increasing the ventilation area compared to the prior art system shown in Fig. 4, the system of Figs. 5-7 has no such design restrictions.

In use, the vented bead 30 is inserted into the glazed vent frame 25 as illustrated in Figs. 2 and 3, and the bottom bead is then inserted as standard. The vertical beads are then inserted, the vertical beads being butt (square) cut at the top end to fit flush with the vented bead.

To complete the glazing process, the vented bead is wedged by the gaskets 38, and end caps are snapped on the ends of the extruded section 54. The ventilation flow is controlled internally by the standard internal trickle vent 21.

The bead unit 30 is prepared by first cutting the extruded section 54 to the full width of the glazing rebate. If the glazing rebate is a standard size (say, 480mm), two standard length vented mouldings 31 (each of 240mm) are then slid into the section 54 to its full length.

For a non-standard opening, an additional piece of the vented moulding is cut from the standard lengths and inserted to fill the required length of section 54.

The extruded section 54 might be formed, for example, of aluminium or PVC, and the injection moulding 31 of ABS.

Claims (5)

1. A trickle ventilation system wherein a ventilation passage through a window frame member has an external vent provided in one of the inwardly facing walls of the member forming a rebate for a glazing panel retained in the window frame.

2. A trickle ventilation system according to claim 1 wherein the external vent is covered by a vented glazing bead engageable with the inwardly facing wall and additionally serving to retain the glazing panel in the rebate.

3. A trickle ventilation system according to claim 2 wherein the vented glazing bead comprises two co-operating parts releasably engageable with one another.

4. A trickle ventilation system according to claim 3 in which a first of the two parts is an injection moulding and the second part is an extrusion.

5. A trickle ventilation system wherein a ventilation passage is formed through a window frame member, and wherein the flow of outside air into the passage is through a vent in a glazing bead engageable with the frame member and serving to retain a glazing panel in the window frame.