EP2157271B1 - Door blank and method for producing same - Google Patents

Description

Technical area

The invention relates to a door blank, in particular a blank for a front door or an apartment door, as well as frame elements for a door blank and a method for producing a door blank.

Background of the invention

Conventional front door blanks belonging to the upper quality class are typically made of high quality and relatively expensive materials. Such high quality materials, e.g. Although natural wood and steel ensure a certain quality of the product, their use at the same time contributes to higher production costs and an increased burden on the environment through a higher demand for wood stocks and higher energy consumption.

A door blank according to the preamble of claim 1 is already known from DE 82 02 848 U1 , of the DE 91 02 819 U1 and the US 2005/284030 known. In such a door blank comprising a frame extending around a substantial circumference of the door blank and a core substantially surrounded by the frame, at least one side is fully coated with a structural stabilizing layer made of a composite material. By using such a stabilizing layer, which may be formed in particular of a fiber-reinforced composite material, it is possible to save high-quality and relatively expensive material, such as natural wood and steel, in the manufacture of the door blank, without jeopardizing the structural stability of the door blank. A disadvantage of these known door blanks, however, is that relatively large amounts of the stabilizing layer are needed, wherein the stabilizing layer in the production is also not very favorable.

The invention has for its object to produce a high quality door blank from less expensive and / or environmentally friendly materials. In other words, the invention should provide a novel door blank which provides the structural and physical requirements of a high-quality door blank, while at the same time reducing the need for wood and steel components. At the same time, the use of required stabilizer layer material is also to be optimized to make the door blank even more cost-effective.

Brief description of the invention

This object is achieved by a door blank having the features of claim 1 and a method for producing a door blank according to claim 9. Further preferred embodiments of the invention will become apparent from the features of the dependent claims.

The door blank according to the invention is suitable for mounting on a door opening, and has the features according to claim 1.

Usually, the blank defines an area suitable for closing the door opening. In the prior art mentioned in the introduction, this surface is covered by the stabilization layer and substantially coincides with the stabilization layer. However, the inventors have surprisingly found that the advantages of the stabilizing layer are still substantially retained, even if the coating with the composite material is restricted to the frame or to the frame elements. In a preferred form of the invention, both sides of the door blank are provided with the stabilizing layer, this coating being limited to the frame or the frame elements. In a preferred embodiment of the invention, the elongated frame members of the door blank are enveloped or wrapped by the stabilizing layer.

In a preferred embodiment of the invention, the frame includes elongated elements which extend around the core and thus define the substantial periphery of the blank. The elongate elements are provided or coated with the structural stabilizing layer consisting of a composite material or a fiber-reinforced composite material on at least one side, preferably on at least two opposite sides (ie on the inside and the outside). Preferably, the elongate elements of the frame are at least partially wrapped by the stabilizing layer. Preferably, the door panel according to the invention has a rectangular shape. The elongated elements of the frame are arranged to form a rectangular frame around the circumference of the blank and the core is substantially surrounded by the elongate elements.

In a preferred embodiment of the invention, at least one - and preferably each - of the frame members consists of a plurality of elongate components or components which are provided with the structural stabilizing layer or coated and interconnected. Preferably, the plurality of components or components of the at least one frame member adjacent or adjacent to each other, preferably in parallel, and more preferably arranged axially in series or in a line and through the Stabilization layer interconnected. The components of the elongate frame members may be made of various materials, such as wood or wood-containing materials, or plastic such as polyurethane (eg, Baydur®), and are preferably square components having a rectangular cross-section.

In a preferred embodiment of the invention, adjacent ends of the elongate components of the at least one frame member are spaced apart. Opposite faces of the adjacent ends of these elongated components are preferably not directly connected to each other and may be e.g. be separated by a gap.

In a preferred embodiment of the invention, the stabilizing layer has a thickness in the range from 0.5 mm to 15 mm, preferably in the range from 1 mm to 10 mm, and more preferably from 1 mm to 5 mm. The stabilization layer is preferably made of a fiber reinforced composite, e.g. Fiber-reinforced plastic, which gives the blank a high structural stability with a small thickness or strength. The fibers in the fiber reinforced composite are preferably of glass (i.e., glass fibers), although other materials for the fibers, e.g. Basalt, carbon or aramid are also possible. The composite matrix of the stabilization layer is preferably composed of one or more plastics, such as e.g. Polyester, vinyl ester, epoxy, polyamide, polyimide, polypropylene or the like. After curing of the composite material, the stabilizing layer gives the frame or the door blank higher structural stability and enables a reduction of the other reinforcing members in the door blank.

In a preferred embodiment of the invention, the stabilization layer consists of at least one layer of the fiber-reinforced composite material. Each ply of the fiber reinforced composite may include one or more fiber layers, and the fibers in each fiber layer preferably extend at least partially in a longitudinal direction of the frame members. For doors with special loads, the stabilization layer can consist of several layers, preferably of several layers of the fiber-reinforced composite material. The multiple layers of the fiber-reinforced composite material preferably run in parallel and can be laid by one or more intermediate layers at a predetermined distance from each other.

In a preferred embodiment of the invention, each frame element has at least one strut which extends in a longitudinal direction of the frame element and is covered or coated by the stabilization layer. Preferably, the strut extends along a substantial length of the frame member and is disposed on an outer side of the frame member. Thus, the strut leads to a reinforcement or stiffening of the frame element. Each frame member preferably includes at least two struts disposed on opposite outer sides of the frame member. Each strut, which preferably has a relatively flat profile, may e.g. be glued on an outer side of the elongated components of the frame member before the stabilization layer is applied. Otherwise, the strut can be received in a recess or groove in the elongated components and glued, if necessary, before the layers of the fiber-reinforced composite material or the stabilization layer is applied. The struts may be formed as bars or reinforcing profiles and are preferably made of a composite material such as e.g. Glass fiber profiles or of a metal such as e.g. Aluminum or steel.

In a preferred embodiment of the invention, the door blank is provided with an outer cover layer or with an outer cover sheet. In this context, the skilled person will understand that the stabilization layer need not be responsible for the appearance of the blank. But the topsheet or topsheet is laid over the stabilizing layer, for example, to produce a suitable appearance of the blank.

In a preferred embodiment of the invention, the frame comprises an inner, statically supporting part and an outer part which extends around an outermost edge of the frame or blank. That is, the frame construction has an inner, force-bearing part and an outer edge part. Preferably, the inner part of the frame is provided with the stabilizing layer and the outer part of the frame is not. The outer part of the frame forms a visible area and serves for the necessary operations, such as seaming, fittings, etc. As the outer part of the frame is visible, it is preferably made of a type of wood which matches the cover sheet, so that it has an aesthetic or decorative function is also guaranteed.

The present invention is a novel construction for a door blank, or door, that can absorb tensile and compressive stresses that arise on a front door due to changing climatic conditions through the fiber reinforced composite stabilizer layer. In addition, this stabilizing layer can reduce the water vapor permeability of the front door. This design has the great advantage that it can be dispensed with a circumferential steel frame in the core of the door blank and on a proportion of wood materials.

In a preferred embodiment of the invention, the core of the blank has at least one and preferably a plurality of parallel layers. The layer or layers of the core may be made of different materials, e.g. Polyurethane, polymer foams such as polystyrene rigid foam (EPS), coarse particle board (OSB), and / or plywood boards. Through a combination of materials in multiple layers, the structure of the core can be optimized for different requirements, e.g. Weight, thermal insulation and / or acoustic insulation.

According to the present invention, a door, in particular a front door or front door is provided which comprises or comprises a door blank according to the invention.

In the conventional method of manufacturing a door blank, the frame and core of the blank, as well as layers or plies, such as e.g. of adhesives or liners, typically laid on a platen in a press machine and brought together. In this way, the application of the stabilizing layer was originally provided on the respective sides of the door blank originally.

However, by a fundamental change in the manufacturing process, the inventors have devised a new preferred embodiment of the invention. According to this embodiment of the invention, the method for producing the door blank, the steps according to claim 9 before.

In this embodiment of the method, frame members are prefabricated with the structural stabilizing layer. In order to realize this embodiment of the invention, an additional or separate method of prefabrication of the frame members is needed, but as a result, a simpler and more flexible method of manufacturing the door blanks is obtained. Further, extensive and lengthy research and development has shown that ultimately the coating is critical to the frame construction, and that coating of the core can be eliminated without significantly compromising the benefits and performance of the stabilization layer.

• Bereitstellen mindestens einer Lage des Verbundwerkstoffes bzw. des faserverstärkten Verbundwerkstoffes,
• Anordnen mehrerer länglicher Komponenten nebenstehend oder benachbart miteinander, bevorzugt in parallel, und weiter bevorzugt axial in Reihe bzw. in einer Linie;
• Aufbringen der Lage des Verbundwerkstoffes auf mindestens eine Seite, bevorzugt auf mindestens zwei gegenüberliegende Seiten, der länglichen Komponenten, um die strukturelle Stabilisierungsschicht zu bilden;

wobei die Lage bzw. Stabilisierungsschicht über die mehreren Komponenten verläuft und sie miteinander verbindet, sodass die Komponenten durch die Stabilisierungsschicht in einem länglichen Rahmenelement vereint werden.In a further preferred embodiment of the invention, the step of prefabricating the elongated frame elements comprises the following steps:

• Providing at least one layer of the composite material or of the fiber-reinforced composite material,
• Arranging a plurality of elongated components adjacent or adjacent to each other, preferably in parallel, and more preferably axially in series or in a line;
• Applying the layer of the composite to at least one side, preferably to at least two opposite sides, of the elongate components to form the structural stabilizing layer;

wherein the layer of stabilization passes over and interconnects the plurality of components such that the components are united by the stabilizing layer in an elongated frame member.

In a preferred embodiment of the invention, adjacent ends of the plurality of axially in-line components are spaced apart and not directly connected.

• Umwickeln oder Umhüllen der länglichen Komponenten mit der Lage bzw. den Lagen des Verbundwerkstoffes. Nach dem Umwickeln oder Umhüllen der länglichen Komponenten kann bzw. können die Lage(n) des Verbundwerkstoffes aushärten, um ein festes oder starres Rahmenelement zu verschaffen.

In a further preferred embodiment of the invention, the step for applying the at least one layer of the composite material comprises the following step:

• Wrapping or wrapping the elongated components with the layer or layers of the composite material. After wrapping or wrapping the elongate components, the sheet (s) of the composite may cure to provide a rigid or rigid frame member.

• Auflegen bzw. Einlegen Verstärkungsstreben in einer Längsrichtung auf bzw. in die nebenstehenden oder benachbarten länglichen Komponenten, bevor die mindestens eine Lage des Verbundwerkstoffes auf die länglichen Komponenten aufgebracht wird.

In a preferred embodiment of the invention, the step of the step of prefabricating the elongated frame members comprises the following further steps:

• Applying reinforcing struts in a longitudinal direction to adjacent or adjacent elongated components before applying the at least one layer of composite to the elongated components.

As already mentioned above, the elongated components of the frame elements are usually square components with a rectangular cross section. After the stabilization layer has cured, but before the frame elements come to be used in a door blank, the frame elements can, however, be further processed and provided, for example with oblique connection surfaces and / or with Aussparrungen who then come into effect later in the assembly of the door blank and / or the resulting door. For example, when the frame members provided with the stabilizing layer have an inner and an outer part, these inner and outer parts can be combined with each other via such connecting surfaces or recesses.

• Anordnen mehrerer länglicher Komponenten nebenstehend oder benachbart miteinander, bevorzugt in parallel, weiter bevorzugt axial in Reihe bzw. in einer Linie; und
• Aufbringen einer strukturellen, aus einem Verbundwerkstoff, insbesondere einem faserverstärkten Verbundwerkstoff, bestehenden Stabilisierungsschicht auf mindestens eine Seite, bevorzugt auf mindestens zwei gegenüberliegenden Seiten, der länglichen Komponenten.

According to another aspect of the invention, there is provided a method of prefabricating an elongated frame member for a door blank, comprising the steps of:

• Arranging a plurality of elongate components adjacent or adjacent to each other, preferably in parallel, more preferably axially in series or in a line; and
• Applying a structural stabilizing layer consisting of a composite material, in particular a fiber-reinforced composite material, to at least one side, preferably on at least two opposite sides, of the elongated components.

• Bereitstellen mindestens einer Lage des Verbundwerkstoffes bzw. des faserverstärkten Verbundwerkstoffes,
• Umwickeln oder Umhüllen der angeordneten, länglichen Komponenten mit der mindestens einen Lage des Verbundwerkstoffes.

In a preferred embodiment of the invention, the step of applying the stabilization layer comprises the following steps:

• Providing at least one layer of the composite material or of the fiber-reinforced composite material,
• Wrapping or wrapping the arranged, elongated components with the at least one layer of the composite material.

In a preferred embodiment of the invention, the step of placing the adjacent or adjacent elongated components on the at least one provided layer of the composite takes place. In other words, the elongated components of the frame member are placed on the uncured layer of the composite material. The at least one layer of the composite is then wrapped or wrapped around the elongate components and preferably pressed together with the components. This can e.g. by pressing the components and composite material into or over a mold. The layers of the composite then cure to provide a rigid or rigid frame member.

In a preferred embodiment of the invention, the stabilizing layer passes over the plurality of components and connects them together. The components are united by the structural stabilization layer in an elongated frame element. In In this context, the material of the composite matrix may have an adhesive property that can be easily bonded to the components. Preferably, the elongated components of each frame member are not previously bonded together but are structurally united in a rigid elongated member by the hardening of the stabilizing layer.

In a preferred embodiment of the invention, the stabilizing layer is applied to the blank or to the frame with a thickness of 0.5 mm to 15 mm, preferably 1 mm to 10 mm, more preferably 1 mm to 5 mm.

In a preferred embodiment of the invention, the stabilizing layer is provided with an outer cover layer or with an outer cover sheet to produce a suitable appearance of the blank.

According to yet another aspect of the invention, a frame member for a door blank is provided. The frame element according to the invention is typically prefabricated by the method described above and has the features described above in connection with the door panel according to the invention. In a preferred embodiment, the invention therefore provides a frame member for a door blank, which consists of a plurality of elongated components, which components of the frame member adjacent or adjacent to each other, preferably in parallel, more preferably axially arranged in series, wherein the plurality of components of the frame member with a structural, consisting of a composite material or a fiber-reinforced composite material, stabilizing layer on at least one side, preferably on two opposite sides, are provided or coated.

According to a further aspect of the invention, kit is provided for a door blank or for a door, wherein the kit has a plurality of frame elements according to the invention. Preferably, the kit according to the invention also comprises a core for the door blank or at least one or more layers from which a core can be constructed.

Brief description of the drawings

Figur 1a bis 1c

schematische Darstellungen des Aufbaus eines Türrohlings jeweils in Draufsicht, Endquerschnitt und Seitenquerschnitt gemäß einem Ausführungsbeispiel, welches nicht Bestandteil der Erfindung ist;

Figur 2a bis 2c

schematische Darstellungen des Aufbaus eines Türrohlings jeweils in Draufsicht, Endquerschnitt und Seitenquerschnitt gemäß einem weiteren Ausführungsbeispiel welches nicht Bestandteil der Erfindung ist;

Figur 3a bis 3c

Darstellungen des Aufbaus eines Türrohlings jeweils in Draufsicht, Endquerschnitt in Richtung der Pfeile "b-b" und Seitenquerschnitt in Richtung der Pfeile "c-c" gemäß einem bevorzugten Ausführungsbeispiel der Erfindung; und

Figur 4

detaillierte Querschnitt-Darstellung des Aufbaus des Rahmens des Türrohlings in dem Bereich "SS" gezeigt in Figur 3b.

The embodiments described above and further preferred embodiments of the invention will become apparent from the following description of exemplary embodiments which with reference to the accompanying figures, wherein functionally similar or functionally similar components are identified by the same reference numerals. It shows:

FIGS. 1a to 1c

schematic representations of the structure of a door blank in each case in plan view, end cross section and side cross section according to an embodiment which is not part of the invention;

FIGS. 2a to 2c

schematic representations of the construction of a door blank in each case in plan view, end cross section and side cross section according to a further embodiment which is not part of the invention;

FIGS. 3a to 3c

Representations of the structure of a door blank respectively in plan view, end cross-section in the direction of the arrows "bb" and side cross-section in the direction of arrows "cc" according to a preferred embodiment of the invention; and

FIG. 4

detailed cross-sectional representation of the structure of the frame of the door blank in the area "SS" shown in FIG. 3b ,

Description of the embodiments

The FIGS. 1a to 1c show purely schematically an embodiment, which is not part of the invention, a door blank 1 for mounting on a door opening. The door blank 1 has a generally rectangular shape and has a frame 2 extending around a substantial circumference of the blank 1. Furthermore, the door blank 1 has a core 3 which is surrounded by the rectangular frame 2.

The frame 2 includes a plurality of elongated elements 4-7, which are interconnected and together form the frame 2. The longer, vertically extending members 4, 6 at the lateral edges of the blank 1 actually assume a substantially vertical posture in use on a door opening. The slightly wider element 6 of the two vertical elements 4, 6 is particularly suitable for the assembly of a hinge. Thus, during mounting of the door blank 1 to a door opening, a hinge (not shown) is attached to the member 6 of the frame 2 and fixed to an adjacent door jamb (not shown). The shorter, horizontally The extending elements 5, 7 at the upper and lower edges of the blank 1 actually assume a substantially horizontal posture in use. In this embodiment, the elongated elements 4-7 of the frame 2 are made of either wood such as spruce, pine, larch, Meranti 450 plus, oak, beech or maple, etc., or a synthetic wood substitute such as polyurethane, Baydur®.

The dimensions of the frame 2 can be adjusted according to the use. In this example, the vertical elements 4, 6 have a length of about 2000 mm to 2200 mm and a thickness (transverse to the plane of the drawing) of about 40 mm to 80 mm, preferably from 65 mm to 75 mm. The width of element 6 (in the plane of the drawing) is approximately twice the width of element 4, in this case about 160 mm. The horizontal elements 5, 7 have a length of about 700 mm to 900 mm, a thickness (across the plane of the drawing) of about 40 mm to 80 mm, preferably from 65 mm to 75 mm, and a width (in the plane of the drawing) of about 30 mm to 50 mm, preferably 35 mm to 45 mm.

Like the frame 2, the core 3 of the door blank 1 has an equally rectangular shape and is surrounded by and connected to the elongate elements 4-7. The core 3 of the blank may have a single-layer or multi-layer structure, and the exact structure of the core 3 will normally be selected and optimized for specific requirements such as weight, thermal insulation and acoustic insulation.

For example, the core 3 can consist of three layers, of which the outer layers of coarse chip (OSB) or plywood boards with a thickness in the range of 5 mm to 15 mm, preferably in the range of 8 mm to 12 mm , and the middle layer of eg Polyurethane having a thickness in the range of 30 mm to 60 mm, preferably in the range of 40 mm to 50 mm. In another example, the core 3 comprises a single layer 31 made of an expanded polystyrene rigid foam (EPS) and having a thickness in the range of 45 mm to 75 mm, preferably in the range of 55 mm to 65 mm ,

Referring again to the FIGS. 1a to 1c the door blank 1 on each of its two opposite sides (ie on the inside and on the outside) on a layer or layer 8, which consists of glass fiber reinforced plastic. Each of these two layers 8 covers the entire side of the door blank 1, namely the entire outer surface of the core 3 and the frame elements 4-7 on the respective side of the blank. Each of the layers 8 forms a structural layer that gives the construction of the blank 1 strength and stability, so that only a few or even no reinforcement by a steel frame or by wood or steel struts in the core 3 of the blank 1 is necessary. Preferably, the glass fiber reinforced layers 8 have a thickness of 1 mm to 5 mm and thus form stabilizing layers on the opposite sides of the door blank 1. Further, each stabilizing layer 8 has the advantage that it is substantially waterproof and not permeable to water vapor, so that weather-related moisture on a built of the blank 1 front door should not affect the structural integrity of the door. It should be noted, however, that the layers 8 need not cover the entire side of the blank 1 to provide the advantages of strength and stability. Only the frame 2 with its frame elements 4-7 benefits from this structural stabilization layer 8; so that the stabilization layer 8 can be limited to the frame elements on the lock side, hinge side, bottom and top. This is important for doors where cutouts are placed inside the core, because the frame construction must accept or absorb all occurring forces.

The FIGS. 2a to 2c show schematically a further embodiment, which is not part of the invention, a blank 1, in which the frame 2 has a slightly different structure. In this case, the vertical elements 4, 6 of the frame 2 have a plurality of elongated components or components. Namely, each of the two vertical members 4, 6 has two components 41, 42 and 61, 62, respectively, which are parallel to each other and connected to each other. These components 41, 42 and 61, 62 of the frame members 4, 6 are made of different materials. The outer components 41, 61 are made of wood, such as spruce, pine, larch, meranti, oak, beech or maple. The inner components 42, 62 are made, for example, of a synthetic material, such as polyurethane, Baydur®.

The outer components 41, 61 are also slightly longer than the inner components 42, 62, so that the ends of at least one of the horizontal elements 5, 7 can be inserted into recesses. The dimensions of the frame elements 4-7 in this embodiment remain otherwise unchanged from those of the example of FIGS. 1a to 1c , The door blank 1 in the FIGS. 2a to 2c is provided on one side with a stabilizing layer 8 made of glass fiber reinforced plastic as in the first embodiment.

With reference now to the FIGS. 3a to 3c as well as the FIG. 4 a preferred embodiment of the invention will be described in more detail. This embodiment shows a door blank 1 according to the invention with a frame 2 which extends around a substantial circumference of the blank 1, and a core 3 which is surrounded by the frame 2. Again in this embodiment, the frame 2 comprises a plurality of elongated elements 4-7, from which it is constructed. However, in this example, the frame members 4-7 have more or less the same structure. The elements 4, 6 extending vertically are, of course, longer than the horizontally extending elements 5, 7, but there is no significant difference in construction. It is important, however, that the frame 2 in this embodiment differs significantly from the others.

More specifically, in this embodiment, the frame 2 has an inner static supporting part 21 and an outer visible part 22 FIG. 3b the outer frame part 22 is shown with dashed lines in order to clearly distinguish it from the inner frame part 21. The outer frame member 22 forms the outermost edge of the frame 2 and is for use in necessary operations such as seaming, fittings, etc. The inner frame member 21, in contrast, is critical to the structural integrity and rigidity of the door blank. The elongated frame elements 4-7 together form at least the inner, statically supporting part 21 of the frame 2 but possibly also the entire frame 2.

Each frame element 4-7 comprises a plurality of elongated components 41, 51, 61, 71, which are arranged side by side and axially in series. In other words, the vertically extending frame members 4, 6 each comprise a plurality of elongated components or components 41, 61 arranged axially in series, and the horizontally extending frame members 5, 7 each comprise a plurality of elongated components 51, 71 arranged in series The individual components or components 41, 51, 61, 71 are all preferably made of the same material, such as made of wood, a wood-containing material or a synthetic material, such as polyurethane, Baydur®.

Adjacent ends 43, 53, 63, 73 of the plurality of elongated components 41-71 have opposed end faces which are not connected to each other. Rather, these end faces are at a distance from each other and are separated by a small gap S, which preferably has a dimension of about 2% of the length of the respective adjacent components 41-71. In this example, the individual components have 41-71 a length of about 50mm, so that the gap S between the respective adjacent components or components is about 1 mm.

Again FIGS. 3b and 3c can be seen, the individual components 41-71 of the individual frame elements 4-7 are provided or coated with a stabilizing layer 8 made of glass fiber reinforced plastic, on the opposite sides of the door blank 1 (ie both on the inside and on the outside) , From the FIG. 4 However, this stabilization layer 8 can be seen much more clearly.

The glass fiber reinforced plastic (GvK) existing stabilization layer 8 is here on the elongated components 41-71 but under a cover layer or a cover sheet 9 which was applied to both inner and outer sides of the door blank 1. In this embodiment, which may be very advantageous for doors with a special load, the GvK stabilization layer 8 has a multilayer structure. The GvK is divided into two layers 81, 83. The first inner layer 81 was applied directly to the components 41-71 and then an intermediate layer 82 as a spacer. As a third, outer layer 83 of the GvK was again applied over the entire surface to stabilize the frame elements 4-7 even more 2. This construction of the frame elements 4-7 and the frame 2 acts here statically in addition to a double-T-beam. The structure of the stabilizing layer 8 is mounted symmetrically to the blank, ie on the inside and outside.

In addition, reinforcing rods V can also be introduced. These preferred reinforcing bars V are shown in dashed lines in FIGS FIGS. 3b and 4 shown. In this example they consist of extruded glass fiber profiles but the bars V can also be made of aluminum or steel (eg St 37). These bars V are placed on the outer side or in a groove of the components 41-71 before the stabilizing layer 8 is manufactured. The individual rods V extend over almost the entire length of the frame elements 4-7 and, together with the stabilization layer 8, finally remain invisible under the cover sheets 9.

The material for the static-carrying part 21 of the frame 2 consists for example of wood and / or wood-containing materials. So that no additional stresses can occur during natural swelling and shrinkage of wood-based materials, the frame elements 4-7 are subdivided into the individual components 41-71. Thus everyone can Components 41-71 of the frame members 41-71 perform for themselves movements, and generate no or only very low stresses throughout the construction.

The outer visible frame member 22 connects to the static supporting frame. This area lies between the two cover sheets 9 and covers the static-carrying part 21 of the frame to the outside. The width of the visible frame area may vary and will be adapted to the requirements of the door leaf and application.

Claims (15)

1. Door blank (1) having
   a frame (2) which extends around a substantial periphery of the door blank,
   a core (3) which is essentially surrounded by the frame (2), and
   a structural stabilisation layer (8) comprising a composite material, in particular, a fibre-reinforced composite material, with which at least one side of the door blank is furnished or coated,
   characterised in that only the frame (2) and not the core (3) is furnished or coated with the structural stabilisation layer (8), comprising a composite material or a fibre-reinforced composite material, on at least one side, preferably on two opposite sides.
2. Door blank (1) according to claim 1, wherein the frame (2) contains elongated elements (4 - 7) which extend around the core (3) and thereby essentially define the periphery of the door blank, and wherein the elongated elements (4 - 7) are furnished or coated with the structural stabilisation layer (8), comprising a composite material or a fibre-reinforced composite material, on at least one side, preferably on two opposite sides.
3. Door blank (1) according to claim 2, wherein at least one of the elongated frame elements (4 - 7) comprises several elongated components (41, 42; 61, 62), wherein the several components (41, 42; 61, 62) of the at least one frame element (4 - 7) are furnished or coated with the structural stabilisation layer (8) and are connected to one another.
4. Door blank (1) according to claim 3, wherein the several components (41, 42; 61, 62) of the at least one frame element (4 - 7) run parallel, and wherein the components are arranged next to one another or alternatively axially in a line and are connected to one another by means of the stabilisation layer (8).
5. Door blank (1) according to claim 4, wherein adjacent ends (43 - 73) of the several elongated components (41 - 71) of the at least one frame element (4 - 7) are arranged at a distance from one another, e.g. by means of a gap (S) and are preferably not directly connected to one another.
6. Door blank (1) according to one of the preceding claims, wherein the stabilisation layer (8) comprises several layers (81 - 83), preferably several layers (81, 83) of the fibre-reinforced composite material, and wherein the several layers of the fibre-reinforced composite material run at a distance from one another by means of at least one intermediate layer (82).
7. Door blank (1) according to one of the preceding claims, wherein the stabilisation layer (8) has a thickness or a strength in the range or 1 mm to 10 mm, and preferably in the range of 1 mm to 5 mm.
8. Door blank (1) according to one of the preceding claims, wherein the door blank has an external surface layer; and/or wherein the frame elements (4 - 7) consist of at least one from wood and polyurethane.
9. Door blank (1) according to one of the preceding claims, wherein the fibre-reinforced composite material has glass, basalt, carbon or aramid fibres.
10. Door blank (1) according to one of the preceding claims, wherein the frame (2) comprises an inner section (21), which is furnished with the stabilisation layer (8), and an external section (22), which is not furnished with the stabilisation layer (8).
11. Door blank (1) according to one of claims 2 to 10, wherein each of the frame elements (4 - 7) has at least one strut (V), preferably at least two struts arranged on opposite external sides of the frame element, which extends in a longitudinal direction of the frame element (4 - 7), preferably arranged along a substantial length and on an external side of the frame element (4 - 7), and is covered or coated by the stabilisation layer (8).
12. Method for the production of a door blank (1) having the following steps:

    Prefabrication of elongated frame elements (4 - 7), which are furnished or coated with a structural stabilisation layer (8), comprising a composite material, in particular, a fibre-reinforced composite material, on at least one side, preferably on at least two opposite sides;

    Construction of a frame (2) of the door blank (1) by arranging the prefabricated frame elements (4 - 7) around a substantial periphery of the door blank; and

    Construction of a core (3) of the door blank, wherein the core (3) is essentially surrounded by the frame elements (4 - 7), and wherein the core is not furnished or coated with the structural stabilisation layer (8), comprising a composite material or a fibre-reinforced composite material.
13. Method according to claim 12, wherein the step for prefabricating elongated frame elements (4 - 7) has the following steps:

    Arranging several elongated components (41, 42; 61, 62) adjoining or adjacent to one another, preferably in parallel; more preferably axially in a row or in a line;

    Applying the structural stabilisation layer (8) comprising a composite material, in particular, a fibre-reinforced composite material, to at least one side, preferably to at least two opposite sides, of the elongated components (41, 42; 61, 62), wherein the stabilisation layer (8) runs across the several components and binds them to one another so that the components and the structural stabilisation layer (8) are joined in an elongated frame element (4 - 7).
14. Method according to claim 13, wherein adjacent ends of the several components (41; 61) arranged axially in a row are arranged at a distance to one another, e.g. by means of a gap (S), and are preferably not directly connected to one another.
15. Method according to claim 13 or 14, wherein opposite end faces of the adjacent ends (43 - 73) of the components (41 - 71 ) are not directly connected to one another and are preferably separated from one another by means of a gap (S).

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