GB2106579A

GB2106579A - Insulated frame member

Info

Publication number: GB2106579A
Application number: GB08225923A
Authority: GB
Inventors: Colin Martin White
Original assignee: BKL Extrusions Ltd
Current assignee: BKL Extrusions Ltd
Priority date: 1981-09-19
Filing date: 1982-09-10
Publication date: 1983-04-13
Also published as: GB2106579B

Abstract

A frame member for a window or door comprises, a metal element 101, 102 having a thermally insulating covering 120, 130, 131 on a part which is otherwise accessible, wherein the covering includes an outer rigid shell 10 of extruded plastics material defining an interior cavity into which has been extruded a foamed plastics material 11. <IMAGE>

Description

SPECIFICATION Window or door frame member This invention relates to frames for windows or doors.

Metal frames are widely used for windows or doors, but have problems in that in cold weather the thermal conductivity of the metal frame member can lead to interior condensation. Metal window frames are commonly made from aluminium alloys, which have a relatively high thermal conductivity. Metal frame members can be covered with a thermally insulating material to overcome this problem, and it is an object of the present invention to provide an improved frame member with a thermally insulating covering.

According to the invention, we provide a frame member for a window or door, comprising a metal element with a portion which is presented at a position which would otherwise be externally accessible when the frame member is installed as part of a window or door structure, but which is provided with a covering of a thermally insulating material, said covering comprising an extrusion of a plastics material with an outer relatively rigid shell defining an interior cavity containing a foamed plastics material which has been extruded into said cavity, said metal element and covering having longitudinally extending formations which interengage to secure the covering and metal element to one another.

When we refer to an externally accessible position, we mean accessible externally of the frame structure when installed, which may be on the interior or exterior of the building having the window or door structure.

The interengaging longitudinally extending formations may include a groove in said covering, and a projection on said metal element, said groove and projection being of a configuration which resists withdrawal of said projection from said groove. A suitable configuration is to have said projection provided with barbs or like formations.

The groove may have a mouth which is narrower than an inner part of the groove, and may have a wall portion which is roughened, serrated or otherwise configured to assist engagement with said projection. One advantage of the covering comprising an extruded shell of a relatively rigid plastics material is that accurate extrusion of such cross-sectional shapes is possible.

The invention will now be described by way of example with reference to the accompanying drawings, of which.~ Figure 1 is a section through a window assembly incorporating frame members according to the invention.

Figure 2 is an enlarged detailed section through the thermally insulating covering of a frame member of Figure 2.

Referring firstly to Figure 1 of the drawings, there is illustrated a window frame assembly occupying an aperture defined by a building structure 100. The window assembly comprises a fixed frame assembly 101 fixed to the building structure and incorporating a mullion or transome member 102, and a moveable frame assembly 103.

The fixed frame assembly 101 is made of members with a main extruded aluminium frame element which in cross section presents front and rear end flange portions 104, 105 and an interconnecting web portion 106. The rear flange portion has a forward facing projection 107, projections 108 which face to the rear of the section, a barbed projection 109, and a further protection or lip 110 at its one free end, inclined to projection 109. The front flange portion has a lip 111, and the web 106 is of cranked shape having a projection 112 which faces the projection 107 to define an undercut groove 11 3.

The frame member 101 is secured to the building structure surrounding the window aperture by a plurality of spaced lug members 114. Each lug member is secured to the building structure by a fastener 11 5, and to the frame member by the engagement of a resilient generally T shaped portion 116 of the lug within undercut groove 11 3. The free end of the opposite limbs of the T shape abut the projections 107,112 while the central portion of the T shape abuts web 106, the material (aluminium alloy) of the lug member being resiliently deformed to fit within groove 113 so that the frame member 101 is securely attached to the building structure.

A mastic seal 11 7 is provided between the projection 111 of the front flange portion 104 and the building structure, and a plastics trim strip 11 8 is fitted at the rear of the frame member, having resilient legs which engage with a lip 119 at the free end of each lug 1 and with a thermally insulating member 120 to be described hereafter.

By virtue of the provision of the thermally insulating member 120 thereon, no metallic part of the outer frame member 101 is accessible at the interior of the building structure. Thus, disadvantages of heat loss and condensation referred to above are overcome.

The moveable frame assembly 103 is formed of an extruded frame member 121 which, as in the case of the fixed frame member, comprises a web and front and rear flange portions. The rear flange portion 122 thereof corresponds in shape to the rear flange portion 105, and receives a thermally insulating member 123 identical to the thermally insulating member 120. The front flange portion, 124, of the moveable frame member has a part which extends generally rearwardly to receive a flexible weather seal 125, and also provides for attachment of a glazing bead 126 by means of which a double glazing panel 127 is secured in position.

The mullion or transome member 102 is of somewhat rectangular hollow form in cross section, and at its rear (i.e. towards the interior of the building structure) is provided with two oppositely directed flange formations 1 28, 129, which as viewed in section are mirror images of one anothers shapes, identical to the rear flange portion 105 on which thermally insulating member 120 fits. Thus, the flanges 128, 129 carry thermally insulating members 130, 131, these members being identical to member 120. A thermally insulating filler strip 132 fits between members 130 and 131. Thus, all parts of the mullion ortrànsome 102 which are accessible from within the building structure are covered by thermally insulating members.The window assembly as a whole thus presents the thermal insulating properties necessary to avoid condensation problems, The thermally insulating covering 120 is shown in greater detail in Figure 2. It comprises an outer, relatively rigid, shell 10 extruded from a plastics material, containing a foamed plastics material 11 which has been extruded into the interior cavity defined by the shell. Suitable materials for the shell and foamed material are appropriate grades of polyvinyl chloride, at least the shell being a relatively hard unplasticised pvc.

Manufacture of the covering 120 would be carried out by a known extrusion process using a die which extrudes the shell through an annular aperture of the required cross-sectional shape, and simultaneously extrudes the foamed material into the interior of the shell.

In cross-sectional shape, the covering 120 comprises a relatively thick body portion from which extend spaced limbs defining a groove 14 and a lip which defines a groove 12 and a recess 13. The groove 12 receives the lip 110 on the metal frame member, the recess 13 receives projection 108, and the groove 14 receives the barbed projection 109 of the metal frame element. It will be noted that the groove 14 has a mouth which is narrower than the innermost part of the groove, and the parts of the shell 10 which define the walls of the groove are serrated. These features assist retention of the barbed projection 109 in the groove 14. Further, the limbs which define the groove 14 are connected to the main body of the covering by portions of relatively reduced cross-section, to facilitate flexing of the limbs as the projection 109 enters the groove 14.

The formation of the thermally insulating covering as an outer shell and a foam interior which has been extruded into the shell means that relatively close tolerances in manufacture can be maintained. A high degree of security in the attachment of the covering to the metal frame element can be achieved, especially in respect of the resistance to withdrawal of the projection 109 from groove 14, and yet the covering is relatively easy to fit to the metal frame element. Such fitting is carried out by entering the projection or lip 110 on the metal frame element into groove 12 in the covering, and moving the covering pivotally therearound to cause projection 109 to enter groove 14.

The foamed material need not completely fill the cross-section of the interior cavity of the shell.

In practise, the foam may not penetrate the narrow sections defined by the limbs which afford the groove 14 and groove 12. The shell may have internal webs for strengthening, and such webs may separate areas which have the foamed material filling from areas which do not. The shell of the covering can be appropriately coloured for the required installation, and the foamed material within the shell also may be coloured, if desired.

Thus the invention provides a window assembly which is effective in use and satisfactory in appearance.

Claims

1. A frame member for a window or door, comprising a metal element with a portion which is presented at a position which would otherwise be externally accessible when the frame member is installed as part of a window or door structure, but which is provided with a covering of a thermally insulating material, said covering comprising an extrusion of a plastics material with an outer relatively rigid shell defining an interior cavity containing a foamed plastics material which has been extruded into said cavity, said covering and metal element having longitudinally extending formations which inter-engage to secure the covering and metal element to one another.

2. A frame member according to Claim 1, wherein said shell and said foamed material are of PVC.

3. A frame member according to Claim 1 or Claim 2 wherein said formations include a groove in said covering and a projection on said metal element, said groove and projection being of a configuration which resists withdrawal of said projection from said groove.

4. A frame member according to Claim 3 wherein said projection on said metal element is barbed.

5. A frame member according to Claim 3 or Claim 4 wherein said groove has a mouth which is narrower than an inner part of the groove.

6. A frame member according to Claim 3, 4 or 5 wherein said groove has a wall portion which is roughened, serrated or otherwise configured to assist engagement with said projection.

7. A frame member according to any one of Claims 3 to 6 wherein said groove is defined by limbs each extending from a body part of said covering and including a portion of relatively reduced cross-sectional area to provide for flexing thereof.

8. A frame member according to any one of Claims 3 to 7 wherein said longitudinally extending formations further comprise a projection extending from said metal member at an inclination to the first said projection, and a further groove in said covering which receives said further projection.

9. A frame member substantially as hereinbefore described with reference to the accompanying drawings.