GB2081352A - Door construction - Google Patents

Abstract

A door construction primarily intended for use in external doors. The construction consists of a separate framing (49; 72) and one or more infilling elements (50, 64) fixed therein. The framing comprising a central layer of wood (10, 12, 14, 16; 40, 42) or wood-based material, partially replaced if desired by thermally insulating material (44), and at least two facing layers (24, 26) on each side of the central layer. The infilling elements consist either of full-length filling, a full-length glazing unit, or combinations of filling and glazing. The facing layer (24) is preferably of metal. The joints (28, 30) between buffing facing layers (24, 26) at the corners of the framing are arranged to be offset with respect to one another, the joints being thus overlapped by adjoining facing layers. The edges (60) of the said infilling elements (50) preferably butt against the inner edges (54) of the framing (49). In addition, separate beads (46) are arranged to overlap the joints between the framing and the infilling elements. At its inner edge the framing (49) is provided on at least one face (56) with a rebate (58) designed to receive part of the corresponding bead (46). <IMAGE>

Description

SPECIFICATION Door construction The present invention is concerned with a door construction especially suited for application in external doors, so-called terrace doors.

It is well known that external doors of wood easily deform under the influence of variations in ambient conditions, partly on account of variations in temperature, but mainly on account of variations in moisture - usually variations in the relative humidity of the air, but also, naturally, in precipitation.

A number of measures have been taken to limit these deformation movements, which affect the performance of the door in that the door may swell and jam tight in its frame, it may bend and become difficult to shut or draughty, etc. One known design which gives excellent results in this context is disclosed in Swedish Patent 339 745. With the design described in the said patent deformation movements in the form of bending are limited to within the preferred value of 4 mm laid down e.g. in Swedish Standard SS 81 73 02. However, even this degree of bending or curvature has been found to give rise to problems in recent years. One reason is the increased demands on the air-tightness of the door. Another is that the so-called closing pressure, which is also affected by bending of the door, has been getting increasing attention recently.This pressure may be so great as to be unacceptable with a curvature of only 3 mm, especially since the rigidity of the door has been increased on account of more stringent security requirements. A study carried out by the Royal Stockholm Institute of Technology shows that existing draught-exclusion systems can at best meet the applicable requirements if the curvature of the door does not exceed 2-2.5 mm.

As a result of this the need has arisen for a door construction which will combine high rigidity (security requirements) with very slight curvature (airtightness, closing pressure), even when the door is exposed to differing ambient conditions on the internal and the external face.

The principal purpose of this invention is to provide a door construction that will meet the above requirements, further advantages and answers to other problems and requirements being obtained at the same time.

The new door construction, in its simplest form, can be described as comprising a framing, substantially fabricated of wood or a wood-based material, and one or more separate infilling elements fixed in the framing.

Previously known framings of normal fabrication, found in window casements and glazed doors, for example, display a number of weaknesses. Such casements and framings are made of solid timber, which means that any faults, such as knots, shakes and the like, may pass from one face to the other. A comparatively high risk of failure exists on this account. Furthermore the known types of framing (casement) cannot be provided with additional insulation, and moreover they lack moisture barriers on both the inside and the outside.

Further, the known framings (casements) are affected by ambient conditions, which means that they easily warp and bend. Neither do they possess flexural rigidity. To provide good air-tightness and reasonable security these framings must be provided with locking at three points, i.e. at the top and bottom corners as well as at the centre.

The corners themselves are weak points inasmuch as they are not particularly strong and split easily. It is not entirely false to assert that the glazing is necessary to stabilize the casement or framing.

A further aim of the invention is to obviate these weaknesses of known constructions. This is made possible by a door construction primarily characterized in that it consists of a separate framing comprising a central layer of wood or wood-based material, which may if desired be partially replaced by thermally insulating material, and at least two facing layers on each side of the central layer, and one or more door infilling elements fixed in the framing, comprising either full-face filling, full-face glazing, or combinations of filling and glazing.

In the two Swedish Patents 144418 and 339745 the positive effect of a full-face metal facing is shown in conjunction with doors with a solid timber framing and with a framing of porous material.

Yet another purpose of the invention is to further improve the constructions in accordance with the above-mentioned Swedish patents. This is made possible in that at least one of the facing layers on both sides of the central layer is made of metal. This design provides the door with extremely and sur prisingly high stability against deformations due to differing ambient conditions on the inside and the outside. While the new construction does have certain similarities to the two last-named patents, it nonetheless displays considerably less tendency to bend. In certain cases curvature amounts to only about 60 % of that occurring with the known constructions. For best results it is preferable to arrange the adjoining facings so that joints between facing layers are offset with respect to one another.The metal sheet may cover the full width of the framing or only part thereof. In a preferred embodiment the width of the framing is covered with aluminium foil or sheet. This design facilitates the bonding of the various sheets to each other and, furthermore, all fabrication can be done with ordinary woodworking tools.

Framings (casements) for windows and glazed doors are normally provided with a rebate against which the infilling element of the window or door, e.g. the glazing, bears on one side. A bead is fixed on the other side. This known design implies on the one hand that the wood of the framing (casement) must be of high quality for reasons of both appearance and function, and on the other hand that the fixed rebate must face inwards, to permit water to run off and to allow venting of the glazing to the outside.

Thus when the framing (casement) is completely fabricated and fitted with hinges it is already deter mined that it is to be used in an inward or outward opening window or door.

Afurtheraim of the invention isto improve the fastening of door infilling elements in the framing.

This is achieved in that the framing is not provided with an ordinary rebate in the manner of the known construction. Instead the outside edges of the said infilling elements butt against the innermost edges of the framing and separate cover strips are provided to conceal the joints between the framing and the infilling. This design offers a number of advantages. The wood is visible only along the outside edge of the framing. Elsewhere the wood is concealed by the facings or the cover strips. When the framing is completely fabricated and provided with hinges infilling elements may be fitted in the manner desired for use as an outward or inward opening door.

The invention will be described below in the form of a number of preferred embodiments, with reference to the accompanying drawings.

Figure 1 shows in perspective one corner of the central sheet of a door framing in a preferred embodiment of this invention.

Figure 2 shows in perspective one corner of the two facing layers of a door framing, intended for application on both sides of a central layer as illustrated in Figure 1.

Figure 3 shows in perspective one corner of the central layer of a door framing, to be used in a modified door construction according to the invention.

Figure 4 shows a section of part of the union between a door framing designed according to the principles of the invention, illustrated in somewhat simplified form, and a door infilling element.

Figure 5 shows in perspective parts of the union between an insulating filling and a glazing unit in a door design according to the principles of the invention.

As illustrated in Figure 1, the central layer of a door framing comprises, at least at the corners, a wooden framing consisting of parallel strips 10,12,14,16.

The strips are arranged so that the joints 18, 20, 22 are not in line with each other. Hence there is no clear line of failure. All unions are made by bonding.

As is more particularly illustrated in Figure 2, two facing layers 24, 26 are applied to each side of the central layer. The inner facing 24 preferably consists of metal and the outer 26 of plywood, chipboard or similar material. The sheets 24, 26 are applied to overlap, so that the end joints 28, 30 between their individual laminations 32, 34 and 36, 38 do not coincide. This in combination with the central layer provides a framing wherein any knots or shakes will not pass from face to face. In addition it provides good thermal insulation. The framing is further found to be surprisingly stable with regard to both flexural rigidity and corner strength. The metal sheets 24 also serve as a good moisture barrier.

The door framing can be insulated in parts. This is preferably effected in the central layer, which is provided in such a case with an inner 40 and an outer 42 wooden lipping between which insulation 44 is inserted. The insulation 44 may be layered alternately with wooden laminations (not illustrated) to ensure high strength. The wooden inner lipping 40 is convenient for fixing separate beads, e.g. 46 or48, designed to support and retain the door infill elements.

The union between the door framing 49 and the infilling element 50 is illustrated in Figure 4 in a simplified form. Hence the individual layers of the framing are not shown. The infilling element 50 consists of a triple glazing unit, including spacing means 52 between the panes along the edges thereof. The door framing is provided on both faces 56 with longitudinal rebates 58 at its inner edge 54.

The width of the inner edge 54 of the framing 49 between the rebates 58 is substantially equal to the width of the outer edge 60 of the triple glazing unit 50. The said widths may differ somewhat on account of possible differences in fastening - glazing compound or rubber profile at the edges of the faces 62 of the unit 50. In the embodiment shown the beads 46 are such that their thickness is substantially equal to the depth of the rebates 58. Their breadth is such that the beads 46 extend a certain distance over the faces 62 of the unit.

A design of the type illustrated in Figure 4 offers very great flexibility of use. This is also true of the design illustrated in Figure 5, wherein the door infilling element 64, consisting in this case of insulating filling, is also provided with longitudinal rebates 66 along the edges 70 of the faces 68 thereof.

It should be noted that the widths of the contact surfaces between the door framing 72 and the filling 64 are equal in the present case. Inward and outward opening doors can be made with identical components in all parts. All wood in the framing is concealed, with the exception of the outer edge. The beads 48 may be very simple and may, as shown, be rectangular in section. Variations in the thickness of the filling 64 have no effect at all, provided that the widths of the contact surfaces above-mentioned are equal. If the width of the contact surfaces of the framing, filling and glazing unit are matched to each other the beads can be made continuous. This means that jointing - with its consequent drawbacks such as leakage etc, at the joint between glazing and filling - is unnecessary.

With the construction in Figure 5 it is possible to use comparatively heavy beads 48. This provides high strength in the fixing of the glazing unit and/or filling 64, but even so the beads will not project any great distance. Therefore they need not collide with the door handle 74. Where beads are planted on the framing this can cause problems.

By applying the principles of the invention it is alse possible to eliminate the horizontal rail conventionally provided between the glazing and the filling in - known designs. The rail provides a means of fixing the glazing and the filling and also holds the door together, i.e. adds to its stability. According to the invention the filling is so formed that the glazing can butt directly thereon. This is shown in Figure 6, where the filling 76 has a projecting horizontal edge 78 against the inside 80 of which one face 82 of the glazing unit rests. The bottom edge of the unit rests directly on the top edge of the filling. An arrangement of this kind involves the minimum number of joints, thus improving air-tightness. Moreover, the wooden beads to be fitted in the rebates 84 may extend the full length of the respective faces of the framing.

Claims (12)

1. A door construction, primarily intended for application in external doors, characterized by consisting of a separate framing (49; 72) comprising a central layerofwood (10,12,14,16; 40,42) or wood-based material, partially replaced if desired by thermally insulating material (44), and at least two facing layers (24,26) on each side of the central layer, and one or more door infilling elements (50; 64) fixed in the framing, comprising either full-length filling, a full-length glazing unit, or combinations of glazing and filling.

2. A door construction as claimed in Claim 1, characterized in that the central sheet, at least at the corners of the framing, is composed of parallel longitudinal wood strips (10, 12, 14, 16) which are so united at their ends that the end joints (18,20,22) are offset with respect to one another.

3. An arrangement as claimed in Claim 1 or 2, characterized in that the framing (49; 72) includes on at least one side of the central layer, a layer (24) of metal, e.g. aluminium foil or sheet.

4. A door construction as claimed in Claim 3, characterized in that the framing (49; 72) includes two facing layers on each side of the central layer, one of the facing layers on at least one side of the central layer consisting of metal and the remaining layers of plywood, wood fibre board or similar material.

5. A door construction as claimed in any of Claims 1 to 4, characterized in that the joints (28, 30) at the corners of the frame in adjoining facing layers (24,26) are offset with respect to one another.

6. A door construction as claimed in any of Claims 1 to 5, characterized in that the layers are bonded together.

7. A door construction as claimed in any of Claims 1 to 6, characterized in that the outer edges (46; 70) of the said door infilling element (50; 64) butt on the inner edges (54) of the framing (49; 72) and that separate beads (46; 48) are provided to cover the joints between the framing and the infillings.

8. A door construction as claimed in Claim 7, characterized in that the framing (49) is provided with a longitudinal rebate (58) at its inner edges (54) on at least one face (56), designed to receive part of the corresponding bead (46).

9. A door construction as claimed in Claim 8, characterized in that the said door infilling element (64) is provided with a longitudinal rebate (66) at the edge (70) of at least one face (68), designed to receive part of the corresponding bead (48).

10. A door construction as claimed in Claim 8, characterized in that the framing (49) is provided on both faces (56) with longitudinal rebates (58) and that the width of the inner edge (54) of the framing between the rebates (58) is substantially equal to the width of the outer edge (46) of the corresponding infilling element (50).

11. A door construction as claimed in Claim 10, characterized in that the said infilling element comprises a sealed glazing unit (50) of thickness substantially equal to the width of the inner edge (54) of the framing (49) between the rebates (58).

12. A door construction as claimed in any of Claims 1 to 11, characterized in that the said infilling comprises a combination of filling and glazing, and that the part of the filling (76) meeting the glazing unit comprises a longitudinal projecting part (78), one face (80) of which bears on one face (82) of the glazing unit.