Field of the invention

This invention relates to a window or door frame comprising a structure, e.g. of metal, which is adapted to receive a lining, e.g. of wood, on one inner side. The invention also concerns a window casement as recited in the preamble of appended claim Z. Description of the prior art It has long been known to make doors and windows with a supporting structure of metal, in particular aluminium. Such constructions are light, strong and resistant. How¬ ever, the aluminium surfaces are not really aesthetically attractive, and the possibilities of varying the appear- ance are comparatively restricted. An all-metal surface on a window or door construction may feel .unpleasantly cold. Further, the metal has a good thermal conductivity.

WO90/02238, for instance, discloses window construc¬ tions with a supporting structure, preferably of alumi- nium, which is adapted to receive lining elements of wood on both the inside and the outside. Several methods of attaching the lining elements on the aluminium structure are described. However, all the embodiments shown have their disadvantages. Thus, WO90/02238 discloses a lining element in ^* hich one long-side edge is inserted and clamped in a groove of the aluminium structure, the purpose being that the lining only should be retained at one edge, the other edge being free. Naturally, the lining element is thus fastened in an extremely unreliable manner, and runs the risk of coming loose also when subjected to insignificant loads. In this embodiment, a large part of the aluminium construction will be visible.

Another embodiment of the above specification is designed to be introduced in a groove which is defined by two outwardly-directed flanges whose outer end portions are angled 90° inwardly towards one another and parallel

to the main plane of the lining element, said end portions being designed to grip or fit into the lining element. In this case, the fastening is secure. However, the lining element cannot be mounted after the window has been as- sembled, and thus cannot be replaced if e.g. damaged.

In yet another embodiment of the above specification, a main lining element is fastened along its long-side edges by means of overlapping side lining elements at each side, or by means of an overlapping side lining element at one side and by engagement with a projecting flange at the other side. This embodiment is very costly, since it takes two or three lining elements to cover each aluminium section. Further, the fastening is rather unreliable, and the lining element can easily come loose when struck by a blow.

At least in the first and the third of the embodi¬ ments illustrated in W090/02238, the lining element must be made of a fairly hard and high-strength material, such as wood or laminated wood, since it is impossible to fas- ten, in the manner illustrated, a soft and low-strength material, such as a material of good heat-insulating capacity. Objects of the invention

One object of the invention is to obviate the above inconveniences and disadvantages by providing a frame for windows or doors, which is adapted to receive, on its inner side, a lining which can be rapidly and expediently secured on, as well as be released from, the frame also after the latter has been assembled and without the use of any cooperating side lining elements. Another object of the invention is that a separate lining element should cover essentially the entire inner side of the frame. Yet another object of the invention is to improve the heat- insulating capacity of the frame, and protect the lining element from any condensation that may form on a cold metal construction. A further object of the invention is to enable the use of comparatively soft and low-strength

lining elements, e.g. lining elements of materials with good heat-insulating capacity. An additional object of the invention is to make it possible to fasten a lining on a frame without using any visible fastening means. Also with window casements, the invention achieves essentially the same objects as above. Summary of the invention

These objects are achieved by a frame which is of the type mentioned in the introduction to this specification and which is characterised in that the lining is made up of at least four separate, elongate elements which are each connectible to said structure by means of a snap con¬ nection allowing them to be releasably mounted on said structure by pressing one of two opposing sides of each element against the inner side of a corresponding portion of the structure of said frame.

The distinctive features of the window casement ac¬ cording to the invention are recited in appended claim Z. Brief description of the drawings In the drawings,

Fig. 1 is a cross-sectional view of a frame according to the invention, Fig. 2 is a cross-sectional view of the frame of Fig. 1 and a triple-glazed pane fixedly mounted therein by means of a clamping strip,

Fig. 3 is a cross-sectional view of the frame of Fig. 1 and a window casement cooperating therewith and adapted for an openable triple-glazed window, and Fig. 4 is a sectional perspective view of parts of a window construction according to the invention. Detailed description of the preferred embodiment

The following description will refer to Figs 1, 2 and 3, whereas Fig. 4 is mainly intended to provide a general view of the positions of the elements forming pa t of the construction. Thus, Fig. 1 is a cross-section of a frame 1 according to the invention. The frame includes a main sec¬ tion or structure 2 and a covering section 3 intended to

form the outside of the door or window construction of which the frame is a part. The main section 2 and the covering section 3 are interconnected by intermediary, web-forming elements or bridges 4, 4' . The covering sec- tion 3 is divided into an inner covering section 3' and an outer covering section 3", which are kept apart by spacers 5, 5'. Preferably, the spacers are U-shaped sections mounted on flanges 6, 6 ¹ projecting from the inner cover¬ ing section 3'. The outer covering section 3" is pressed over the spacers in such a manner that an inward-facing flange member 7 at one edge of the outer covering section engages one spacer 5' , and a bead 8 at the other edge of the outer covering section is snapped over the curved part of the spacer 5. The inward-facing flange member 7 has a groove 9 adapted to receive a seal, as will be described further below. The spacers 5, 5' suitably extend along the entire frame section to form a closed, heat-insulating air gap between the inner and outer covering sections. The invention is based on the idea that the main section 2 and the covering sections 3' and 3" are made of a resistant and high-strength metal, such as aluminium, whereas the bridges 4, 4 ¹ and the spacers 5, 5' are made of a material with much better heat-insulating properties, e.g. poly- vinyl chloride plastic, to disrupt the thermal bridge which would otherwise arise in the construction, between the inside and the outside of the building. As a compari¬ son, it may be mentioned that the thermal conductivity or the coefficient of thermal conductivity of aluminium is about 220 W/m K, whereas that of polyvinyl chloride plastic is about 1.0 W/m K. Suitably, the main section 2 and the inner covering section 3* are joined by moulding the bridges 4, 4' in the position apparent from Fig. 1, whereas the outer covering section is snapped in place after the spacers 5, 5' have been applied to the inner covering section. Since the outer covering section 3" is snapped in position, it may be replaced later if damaged. In practice, it is preferred that the connection between

the main section 2 and the inner covering section 3' consists of two bridges 4, 4' with an intermediate, closed air gap 10. This gives the construction better heat-insu¬ lating properties than if the connection were in the form of a single homogeneous bridging member. Also, the con¬ struction becomes less expensive as well as lighter, since less material is required.

That part of the main section 2 which is intended to face inwards in the building is formed with a groove 11 adapted to receive an inner lining 12, suitably a wood fillet. This fillet is to be snapped into the groove 11 behind beads 13, 13' on flanges 14, 14' projecting from the main section and forming the side walls of the groove 11. To achieve distinct and reliable snapping-in of the wood fillet 12, the latter preferably has a substantially U-shaped section 15 of polyvinyl chloride plastic, which, via inwardly projecting portions 16, 16' at its leg edges, engages a groove in one edge of the wood fillet and a corner of a groove formed in the other edge. The plastic section is intended to be concealed between the wood fillet and the main section. Since shoulders 17, 17' are formed at the outer leg edges of the U-shaped section and engage behind the beads 13, 13' when the wood fillet is introduced in the groove 11, the fillet will be securely retained in the groove on the main section. The plastic section 15 also serves to remove the wood fillet from the main section 2, thereby avoiding that any moisture will condense on the metal surface of the main section and damage the wood fillet. The plastic section 15 need not extend along the entire length of the wood fillet, but is suitably applied in the form of short spaced-apart pieces. It is highly advantageous that the inner lining of the frame can be snapped in position and thus dismounted if need be. In this manner, the inner lining of the frame can be mounted after the window has been positioned in the building, owing to the rapid and expedient snap action. This obviates the need for large stocks of windows and

doors, since every customer may choose the inner lining he requires. Thus, the lining need not necessarily be made of wood, and many other materials may also be used. In this manner, much of the damage usually caused to the insides of the windows when transported and mounted will be avoid¬ ed. Further, it is possible to simply and expediently re¬ place the lining when the house later is being renovated.

A projecting flange 18, shown in Fig. 1, is an exten¬ sion of the flange 14 and is formed with grooves or barbs, the idea being that covering boards arranged round the window opening and having a previously milled groove will cover the flange 18 and be retained by means of the grooves.

In the cavity between the inner and outer covering sections 3', 3", there are provided an angular flange 19 and an inclined flange 20. When the frame is placed in the lower part of a window, these flanges serve to divert any water that may penetrate into the construction. The water is drained off by holes 21 and 22, as indicated in the Figure. The small groove 23 at the outside of the outer covering section is to contain the upper edge of a window ledge.

The frame shown can be fixed in the building struc¬ ture in different ways, e.g. by screws through the main section or by mountings engaging interfacing grooves 24 and 25 of the frame.

Fig. 2 illustrates the placement and the function of the frame in a window construction. The window shown is a fixed, non-openable window with a triple-glazed sealed glazing unit 26. The windowpane is clamped between an outer rubber seal 27 in the groove 9 of the outer covering section of the frame and an internally positioned clamping section 28. The clamping section has two legs 29, 29' equipped with beads 30, 30' which engage an edge 31 of a groove 32 in the main section, and an edge 33 on a portion projecting from the main section. Apart from pressing the windowpane between the outer seal 27 and an inner seal 34,

the clamping section is also intended to keep in place a wood lining 35. To this end, the clamping section 28 is formed with three projecting flanges 36, 37, 38, the flanges 36 and 37 being formed with barbs or grooves for engaging corresponding grooves in the wood lining. Between the sealed glazing unit 26 and the frame 1 is formed a closed space 58 which is well protected from the outside temperatures since the covering section is made up of two part sections with intermediate spacers. Thus, the heat insulation is improved, and moisture is prevented from condensing in the construction.

Fig. 3 illustrates the frame according to the inven¬ tion when cooperating with a window casement 39 of an openable, linked window, more precisely of the type having an inner window casement 40 with a double-glazed sealed glazing unit 41, and an outer window casement 42 with a single pane 43. Sealing strips 59 and 60 are applied bet¬ ween the casement and the frame, as is apparent from the Figure. The window casement is constructed in essentially the same manner as the frame, and more precisely comprises a main section or inner-casement section 44, which is connected to an intermediate section 46 by bridges 45, 45' of polyvinyl chloride plastic. The intermediate section is articulated to an outer-casement section 46 of the outer window casement 42 by means of a specially designed link element 48 to be described in more detail further below. Also, there is provided a seal 61 between the outer-case¬ ment section and the intermediate portion. The outer pane 43 is clamped between the outer-casement section 47 and an outer clamping section 49 snapped on to the outer-casement section with the aid of an intermediate spacer 50 of the same type as the spacers 5, 5' of the covering section of the frame. Like the frame, the window casement comprises a plurality of bridges disrupting thermal conductivity and interconnecting the different sectional elements of alu¬ minium, thereby obstructing thermal conductivity through the construction. The inner double-glazed pane 41 is

clamped between a flange 51 projecting from the inner- casement section 44 and a clamping section 52. The latter is snapped into a groove 53 in the intermediate section 47. As in the frame, the inside of the window casement is equipped with a lining 54, e.g. of wood, which can be snapped on to the inside of the window casement by means of a concealed aluminium section 55 attached to the wood lining.

In a preferred embodiment, the link element 48 is an elongate, mainly rigid body which preferably is symmetri¬ cal in relation to a plane in the longitudinal direction of the element, and whose cross-section essentially has the shape of a twist bun, as is apparent from the Figure. More precisely, each of the symmetrical parts has a substantially straight portion 56 and a substantially semicircular portion 57 defining between themselves a semicircular groove 62. The semicircular portions of the two symmetrical parts are further interconnected in the symmetrical plane, as is apparent from the Figure. The inner and the outer window casements are formed with grooves or recesses of essentially the same shape as the outer contours of the straight portion 56 and the semi¬ circular portion 57 of the link element. Moreover, there is an edge portion 63 which is introduced into the groove 62 when the window casements are swung out and away from one another. The grooves are further so designed that the link element can be snapped into them, for which reason said element must be at least partly resilient. The centres of curvature of the two semicircular portions 57 are located at the points 64 and 64' , which means that the outer window casement 42 can be swung out from the inner window casement 40 by pivoting about these points at the two symmetrical parts. Thus, there will be a simultaneous pivotal movement about two parallel axes 64, 64' . The link element described has several advantages as compared with conventional hinges. Thus, the device according to the in¬ vention constitutes an inexpensive and rapidly and expedi-

ently mounted linkage system in the window casement. Further, it is possible to manufacture the link elements of a material with better heat-insulating properties than the metal in the window casements, e.g. polyvinyl chloride plastic, thereby producing a bridge disrupting the thermal conductivity therebetween. Displacement of the link ele¬ ment in relation to the grooves in the intermediate sec¬ tion 46 and the outer-casement section 47 when the window is so placed that the link element is in vertical posi- tion, can be prevented by extending the link element along the entire length of the grooves, so that the end surface of the link element will, at the top as well as at the bottom, be applied against the horizontal window-casement pieces applied perpendicular to the vertical window-case- ment piece.

It goes without saying that the invention can be modified in many ways within the scope of the appended claims. Thus, the invention is not restricted to a frame snap connection consisting of two deformable flanges pro- jecting from the main section, or to a window-casement snap connection consisting of a deformable flange project¬ ing from the aluminium section 55. It will be appreciated that different combinations of these embodiments are conceivable within the scope of the invention. Likewise, the two fastening elements 15 and 55 may be manufactured of any suitable material.