Door leaf
The door leaf design combines a fireproof core with a concealed metal sheet to achieve high security and fire safety without compromising weight or appearance, addressing the trade-offs in existing door leaf technologies.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- KINGSWAY ENTERPRISES (UK) LTD
- Filing Date
- 2026-01-16
- Publication Date
- 2026-07-30
AI Technical Summary
There is often a trade-off between fireproof, lightweight, and high-security properties in door leaves, with each property compromising the others in terms of weight, security, and aesthetic appearance.
A door leaf design that incorporates a fireproof core lined with a concealed metal sheet, such as steel, secured by screws or adhesive, which enhances security without increasing weight or compromising aesthetics.
The design provides enhanced security and fire safety while maintaining a lightweight and aesthetically pleasing appearance, suitable for psychiatric environments.
Smart Images
Figure EP2026051023_30072026_PF_FP_ABST
Abstract
Description
[0001] DOOR LEAF
[0002] Field
[0003] The present disclosure relates to a door leaf.
[0004] Background
[0005] Door leaves can be designed to be fireproof, lightweight, or high-security. However, there is often a trade-off to be made between these requirements. For example, using fireproof materials may be at the expense of security and / or weight. Similarly, using lightweight materials may be at the expense of fire safety and / or security.
[0006] Finally, using high-security materials may be at the expense of fire safety, weight, and / or aesthetic appearance.
[0007] Summary
[0008] An aspect of the present disclosure is set out in claim 1. Other aspects and features of the present disclosure are set out in the dependent claims and in the description below.
[0009] Brief description of the drawings
[0010] Implementations of the present disclosure are described below, by way of example, with reference to the accompanying drawings, in which:
[0011] Fig. 1 shows an exploded view of a first door leaf according to the present disclosure;
[0012] Fig. 2 shows a cutaway view through an assembled first door leaf according to Fig. 1 ;
[0013] Fig. 3 shows an exploded view of a second door leaf according to the present disclosure;Fig. 4 shows a cutaway view through an assembled second door leaf according to Fig. 3;
[0014] Fig. 5 shows a method of manufacturing a first door leaf according to Figs. 1 and 2; and
[0015] Fig. 6 shows a method of manufacturing a second door leaf according to Figs. 3 and 4.
[0016] Like reference numerals are used for like components throughout the detailed description.
[0017] Detailed description
[0018] In overview, the present disclosure relates to a door leaf which comprises a fireproof core lined with a metal sheet. The fireproof core provides fire safety, while the metal sheet improves security without unduly increasing weight. The metal sheet is provided between the fireproof core and an outer surface of the door leaf, such that the metal sheet may be concealed from view. The inventor has found that this combination of features provides the benefits of a high-security metal door. However, by providing a metal sheet which is concealed under the outer surface of the door leaf, the aesthetic appearance of the door is not compromised. Accordingly, when used in psychiatric environments, the door provides good security without having an appearance which risks negatively affecting patients’ wellbeing.
[0019] This overview is provided to introduce in simplified form a selection of concepts that are further described herein. The presence of a feature in this overview does not necessarily imply that the feature is essential to the disclosure.
[0020] The present disclosure will now be described in general terms, before implementations of the disclosure are described by way of example with reference to the drawings. The word “may” is used to refer to a feature that is optional, i.e. in some implementations of the disclosure, the feature is present, and in some implementations of the disclosure, the feature is not present.The present disclosure relates to a door leaf. The door leaf comprising one or more of: a fireproof core; a first surface sheet provided on a first side of the fireproof core; a second surface sheet provided on a second side of the fireproof core; and a first metal sheet provided on the first side of the fireproof core, between the fireproof core and the first surface sheet.
[0021] The inventor has surprisingly found that providing a metal sheet in the door leaf does not negatively affect fire safety of the door leaf.
[0022] The first metal sheet may comprise a steel sheet. The metal sheet may be attached to the core by adhesive. Additionally or alternatively, the door leaf may further comprise at least one screw, pin or rivet which extends through the first metal sheet and the core, to thereby secure the first metal sheet to the core. The at least one screw, pin or rivet may be concealed under the first and second surface sheets. The inventor has found that the use of a screw, pin or rivet further helps with fire safety, by preventing delamination of the metal sheet(s) even in the case of an adhesive melting.
[0023] A screw may be preferred in some examples. For example, a screw may provide for simpler manufacture of the door.
[0024] The or each metal sheet may have a thickness of at least 0.5mm, for example at least 1 mm. The or each metal sheet may have a thickness of at most 5mm, for example at most 2mm. The or each metal sheet may for example have a thickness of 1 ,5mm.
[0025] The fireproof core may be formed of wood. The use of a wood fireproof core ensures a low weight to the door leaf, while at the same time providing good fire safety. To the extent that the use of a fireproof core sacrifices on security, the inventor has found that the use of the metal sheet improves security.
[0026] The fireproof core may have a fire door rating of at least FR30. That is to say, the fireproof core may provide at least 30 minutes of fire protection.The fireproof core may have a thickness of at least 30mm, for example at least 40mm. The core may have a thickness of at most 60mm, for example at most 50mm. The core may for example have a thickness of 44mm.
[0027] The fireproof core may comprise a hardwood central layer of 32mm thickness, laminated between two 6mm thick layers of medium density fibreboard (“MDF”), for a total core thickness of 44mm. The fireproof core may for example be a Flamebreak FF630 core.
[0028] The first and second surface sheets may define external surfaces of the door leaf. Each of the first and second surface sheets comprises a veneer sheet, such as a wood veneer sheet. Each surface sheet may have a thickness of at least 0.2mm, for example at least 0.4mm. Each surface sheet may have a thickness of at most 1 mm, for example at most 0.6mm. Each surface sheet may for example have a thickness of 0.5mm.
[0029] The door leaf may further comprise a first lining sheet provided under the first surface sheet, and a second lining sheet provided under the second surface sheet. The first lining sheet may be provided between the first surface sheet and the first metal sheet. Where a second metal sheet (for example a second steel sheet) is present, the second lining sheet may be provided between the second surface sheet and the second metal sheet. Each of the first and second lining sheets may be a plywood sheet, or an MDF sheet. Each lining sheet may have a thickness of at least 1 mm, for example at least 2mm. Each lining sheet may have a thickness of at most 6mm, for example at most 4mm. Each lining sheet may for example have a thickness of 3mm.
[0030] An adhesive may be provided between each layer of the door leaf.
[0031] The total thickness of the door leaf may be at least 40mm, for example at least 50mm. The total thickness of the door leaf may be at most 70mm, for example at most 60mm. Where the door leaf comprises two steel sheets, two lining sheets, and two surface sheets, the total thickness of the door leaf may for example be 54mm.The sheets of the door leaf may be attached to one another by an adhesive. They may also be attached the core by an adhesive.
[0032] The door leaf may further comprise a second metal sheet provided on the second side of the fireproof core, between the fireproof core and the second surface sheet. The second metal sheet may comprise a steel sheet.
[0033] The first and second metal sheets may be attached to the core by an adhesive.
[0034] Additionally or alternatively, the door leaf may further comprise at least one screw, pin or rivet which may extend through the first metal sheet, the core and the second metal sheet, to thereby secure the first and second metal sheets to one another and to the core.
[0035] The at least one screw, pin or rivet may be concealed under the first and second surface sheets.
[0036] The door leaf may further comprise lipping extending around an edge of the door leaf. The lipping may conceal the core, the metal sheet(s) and the lining sheets. The lipping may be formed of wood.
[0037] The door leaf may have a thickness of at least 40mm, for example at least 50mm. The door leaf may have a thickness of at most 70mm for example at most 60mm. In an example, the door leaf may for example have a thickness of 54mm.
[0038] Each possible combination of any of the above-described features forms part of the present disclosure. A plurality of instances of any feature may also be present. By way of example, implementations of the disclosure will now be described with reference to the drawings. Each possible combination of any features described below with any features described above also forms part of the disclosure.
[0039] Fig. 1 shows an exploded view of a first door leaf 100 according to the present disclosure.The door leaf 100 comprises a fireproof core 102, a first surface sheet 104a on a first side of the fireproof core 102, a second surface sheet 104b on a second side of the fireproof core 102, a first steel sheet 106a between the first surface sheet 104a and the fireproof core 102, and a second steel sheet 106b between the second surface sheet 104b and the fireproof core 102. An adhesive layer (not shown in Fig. 1) is also provided between each layer, to bond the layers of the door leaf 100 together. The same adhesive is typically used between each layer. The adhesive may be a spray contact adhesive, such as an air-cured spray contact adhesive. In some examples, a different adhesive may be used for the surface sheets104a, 104b. For example, the surface sheets 104a, 104b may alternatively be adhered to the outer surfaces of the door leaf using a polyurethane resin. Each surface sheet covers the entire surface of the steel sheet to which it is attached.
[0040] In addition to the adhesive, screws 108 are provided to secure the steel sheets 106a, 106b to the core. Four screws 108 are used - one adjacent each corner of the door leaf. Each screw 108 extends through the first steel sheet 106a, the core 102, and the second steel sheet 106b, in order to secure the first steel sheet 106a, core 102 and second steel sheet 106b together. The surface sheets 104a, 104b cover the screws 108, such that the screws 108 are concealed from view in the assembled door leaf.
[0041] Finally, an elongate lipping 110 is provided along the edges of the door leaf 100. That is, a first elongate lipping 110a is provided along a first edge, a second elongate lipping 110b is provided along a second edge, a third elongate lipping 110c is provided along a third edge, and a fourth elongate lipping 110d is provided along a fourth edge. The elongate lippings are attached to their respective edges by an adhesive, typically the same adhesive as is provided between the layers of the door leaf 100. The elongate lippings cover the edges of the door leaf 100, so as to conceal the core 102 and the steel sheets 106a, 106b from view when the door leaf is assembled. Each lipping typically comprises a wood lipping.
[0042] The core 102 is a Flamebreak FF630 core, having a total thickness of 44mm. It may comprise a hardwood central layer of 32mm thickness, laminated between two 6mm thick layers of medium density fibreboard (“MDF”). Each steel sheet 106a, 106b is1.5mm thick, and covers the entire surface of the core 102 to which it is attached. Each surface sheet comprises a veneer, such as a wood veneer. Each veneer sheet has a thickness of 0.5mm. Accordingly, the door leaf 100 of Fig. 1 has a total thickness of 48mm. However, as the reader will understand, the present disclosure is not intended to be limited to these measurements.
[0043] Although two steel sheets 106a, 106b are shown in Fig. 1 , the door leaf 100 may in an alternative arrangement be provided with only one steel sheet 106a. That is, a first steel sheet 106a may be provided between the first surface sheet 104a and the core 102, and the second surface sheet 104b may be adhered directly to the core 102, with no intervening steel sheet.
[0044] Fig. 2 shows a cutaway view of the door leaf 100, once assembled. Once assembled, the surface sheets 104a, 104b conceal the steel sheets 106a, 106b and the screws 108. Furthermore, the lipping 110 conceals the core 102 and the steel sheets 106a, 106b.
[0045] Fig. 3 shows an exploded view of a second door leaf 300 according to the present disclosure. The second door leaf 300 corresponds to the first door leaf 100 in all respects apart from any differences that are apparent from the following description.
[0046] As shown in Fig. 3, the second door leaf 300 further includes a first lining sheet 302a and a second lining sheet 302b. The first lining sheet 302a is provided between the first surface sheet 104a and the first steel sheet 106a. The second lining sheet 302b is provided between the second surface sheet 104b and the second steel sheet 106b. The same adhesive as described above is used to secure the lining sheets 302a, 302b to the respective steel sheets 106a, 106b and to the respective surface sheets 104a, 104b. Further, each of the first and second lining sheets 302a, 302b covers the screws 108. Each lining sheet 302a, 302b covers the entire surface of the metal sheet 106a, 106b to which it is attached. Each surface sheet 104a, 104b covers the entire surface of the lining sheet 302a, 302b to which it is attached.
[0047] The first and second lining sheets 302a, 302b each comprise a plywood sheet. The first and second lining sheets 302a, 302b each have a thickness of 3mm.Accordingly, the total thickness of the door leaf 300 of Fig. 3 is 54mm, although as the reader will understand the present disclosure is not intended to be limited to this measurement.
[0048] Although two steel sheets 106a, 106b are shown in Fig. 3, the door leaf 300 may in an alternative arrangement be provided with only one steel sheet 106a. That is, a first steel sheet 106a may be provided between the first surface sheet 104a and the first lining sheet 302a, and the second surface sheet 104b may be adhered directly to the second lining sheet 302b, with no intervening steel sheet.
[0049] Fig. 4 shows a cutaway view of the second door leaf 300, once assembled. As shown, the lipping 110 further covers the lining sheets 302a, 302b, such that the lining sheets are not visible when the door leaf 300 is assembled.
[0050] Fig. 5 shows a method 500 of manufacturing a first door leaf 100 according to the present disclosure.
[0051] In step 502, an adhesive is applied to each surface of the core 102.
[0052] In step 504, a first steel sheet 106a is attached to a first surface of the core 102, and a second steel sheet 106b is attached to a second surface of the core 102.
[0053] In step 506, four holes are drilled through the door leaf 100, each hole being located adjacent a respective corner of the door leaf 100.
[0054] In step 508, a screw 108 is passed through each hole and is secured in place, thereby further securing the steel sheets 106a, 106b to the core 102.
[0055] In step 510, an adhesive is applied to the outer surface of each steel sheet 106a, 106b.
[0056] In step 512, a first surface sheet 104a is attached to the first steel sheet 106a, and a second surface sheet 104b is attached to the second steel sheet 106b.In step 514, adhesive is applied around the edges of the door leaf 100.
[0057] In step 516, a first lipping 110a is attached to a first edge of the door leaf, a second lipping 110b is attached to a second edge of the door leaf, a third lipping 110c is attached to a third edge of the door leaf, and a fourth lipping 110d is attached to a fourth edge of the door leaf.
[0058] In step 518, the door leaf 100 is left to cure, during which time the adhesive hardens.
[0059] Fig. 6 shows a method 600 of manufacturing a second door leaf 300 according to the present disclosure.
[0060] In step 602, an adhesive is applied to each surface of the core 102.
[0061] In step 604, a first steel sheet 106a is attached to a first surface of the core 102, and a second steel sheet 106b is attached to a second surface of the core 102.
[0062] In step 606, four holes are drilled through the door leaf 100, each hole being located adjacent a respective corner of the door leaf 100.
[0063] In step 608, a screw 108 is passed through each hole and is secured in place, thereby further securing the steel sheets 106a, 106b to the core 102.
[0064] In step 610, an adhesive is applied to the outer surface of each steel sheet 106a, 106b.
[0065] In step 612, a first lining sheet 302a is attached to the first steel sheet 106a, and a second lining sheet 302b is attached to the second steel sheet 106b.
[0066] In step 614, an adhesive is applied to the outer surface of each lining sheet 302a, 302b.
[0067] In step 616, a first surface sheet 104a is attached to the first lining sheet 302a, and a second surface sheet 104b is attached to the second lining sheet 302b.In step 618, adhesive is applied around the edges of the door leaf 100.
[0068] In step 620, a first lipping 110a is attached to a first edge of the door leaf, a second lipping 110b is attached to a second edge of the door leaf, a third lipping 110c is attached to a third edge of the door leaf, and a fourth lipping 110d is attached to a fourth edge of the door leaf.
[0069] In step 622, the door leaf 100 is left to cure, during which time the adhesive hardens.
[0070] Each possible combination of any features from the implementations described above forms part of the present disclosure.
[0071] Aspects of the present disclosure are set out below. Each item below corresponds to an aspect of the disclosure, and each possible combination of any of the items corresponds to an aspect of the disclosure. When items are combined, two or more instances of an element with the same name are to be understood as referring to the same element, even if the element is introduced by the word “a” more than once. Each possible combination of any features from the items below with any features described above also forms part of the disclosure.
[0072] 1. A door leaf comprising a fireproof core lined with at least one metal sheet, for example at least one steel sheet.
[0073] 2. The door leaf of item 1 , wherein the fireproof core is formed of wood.
[0074] 3. The door leaf of item 2, wherein the door leaf comprises a wood outer layer.
[0075] 4. A method of manufacturing a door leaf according to the present disclosure.
[0076] 5. The method of item 4, the method comprising attaching a metal sheet to a fireproof core.
[0077] 6. The method of item 5, wherein the fireproof core is formed of wood.7. The method of item 5 or item 6, wherein the metal sheet is a steel sheet.
[0078] 8. The method according to any of items 4 to 7, wherein attaching the metal sheet to the fireproof core comprises drilling a hole through the fireproof core and the metal sheet, and securing a screw, pin or rivet through the hole.
[0079] 9. The method according to any of items 4 to 8, further comprising attaching a surface sheet to the metal sheet.
[0080] 10. The method according to any of items 4 to 9, wherein the surface sheet is formed of wood.
[0081] It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other implementations will be apparent to those of skill in the art upon reading and understanding the above description. Although the present disclosure has been described with reference to specific implementations, it will be recognized that the disclosure is not limited to the implementations described, but can be practiced with modification and alteration. Accordingly, the specification and drawings are to be regarded in an illustrative sense rather than a restrictive sense. The scope of protection should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
Claims
CLAIMS1. A door leaf comprising:a fireproof core;a first surface sheet provided on a first side of the fireproof core;a second surface sheet provided on a second side of the fireproof core; and a first metal sheet provided on the first side of the fireproof core, between the fireproof core and the first surface sheet.
2. The door leaf according to claim 1 , further comprising at least one screw, pin or rivet which extends through the first metal sheet and the core, to thereby secure the first metal sheet to the core.
3. The door leaf of claim 2, wherein the at least one screw, pin or rivet is concealed under the first and second surface sheets.
4. The door leaf of any preceding claim, wherein the fireproof core comprises a wood fireproof core.
5. The door leaf of any preceding claim, wherein the fireproof core has a fire door rating of at least FD30.
6. The door leaf of any preceding claim, wherein the first and second surface sheets define external surfaces of the door leaf.
7. The door leaf of any preceding claim, wherein each of the first and second surface sheets comprises a veneer sheet.
8. The door leaf according to any preceding claim, further comprising a first lining sheet provided under the first surface sheet, and a second lining sheet provided under the second surface sheet.
9. The door leaf of claim 8, wherein the first lining sheet is provided between the first surface sheet and the first metal sheet.
10. The door leaf of claim 8 or claim 9, wherein the first and second lining sheets comprise plywood sheets.
11. The door leaf according to any preceding claim, wherein the sheets of the door leaf are attached to one another by an adhesive.
12. The door leaf of any preceding claim, further comprising a second metal sheet provided on the second side of the fireproof core, between the fireproof core and the second surface sheet.
13. The door leaf of claim 12 when dependent on any of claims 8 to 10, wherein the second lining sheet is provided between the second surface sheet and the second metal sheet.
14. The door leaf according to claim 12 or claim 13, wherein the first and second metal sheets are attached to the core by an adhesive.
15. The door leaf according to any of claims 12 to 14, further comprising at least one screw, pin or rivet which extends through the first metal sheet, the core and the second metal sheet, to thereby secure the first and second metal sheets to one another and to the core.
16. The door leaf of claim 15, wherein the at least one screw, pin or rivet is concealed under the first and second surface sheets.
17. The door leaf of any preceding claim, further comprising lipping extending around an edge of the door leaf.
18. The door leaf of claim 17, wherein the lipping conceals the core, the metal sheet(s) and the lining sheets.
19. The door leaf of claim 17 or claim 18, wherein the lipping is formed of wood.
20. The door leaf of any preceding claim, wherein the or each metal sheet comprises a steel sheet.14