GB2426998A - Letterplate with intumescent seal and heat resistant fasteners - Google Patents
Letterplate with intumescent seal and heat resistant fasteners Download PDFInfo
- Publication number
- GB2426998A GB2426998A GB0511863A GB0511863A GB2426998A GB 2426998 A GB2426998 A GB 2426998A GB 0511863 A GB0511863 A GB 0511863A GB 0511863 A GB0511863 A GB 0511863A GB 2426998 A GB2426998 A GB 2426998A
- Authority
- GB
- United Kingdom
- Prior art keywords
- letterplate
- door
- frame
- frames
- heat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000004033 plastic Substances 0.000 claims abstract description 12
- 229920003023 plastic Polymers 0.000 claims abstract description 12
- 239000000463 material Substances 0.000 claims abstract description 10
- 239000000378 calcium silicate Substances 0.000 claims description 3
- 229910052918 calcium silicate Inorganic materials 0.000 claims description 3
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 claims description 3
- 229910010293 ceramic material Inorganic materials 0.000 claims description 3
- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical compound [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 claims description 3
- 239000000391 magnesium silicate Substances 0.000 claims description 3
- 229910052919 magnesium silicate Inorganic materials 0.000 claims description 3
- 235000019792 magnesium silicate Nutrition 0.000 claims description 3
- 210000003195 fascia Anatomy 0.000 description 3
- 239000000446 fuel Substances 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47G—HOUSEHOLD OR TABLE EQUIPMENT
- A47G29/00—Supports, holders, or containers for household use, not provided for in groups A47G1/00-A47G27/00 or A47G33/00
- A47G29/12—Mail or newspaper receptacles, e.g. letter-boxes; Openings in doors or the like for delivering mail or newspapers
- A47G29/122—Parts, details, or accessories, e.g. signalling devices, lamps, devices for leaving messages
- A47G29/126—Lids for access slits
-
- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47G—HOUSEHOLD OR TABLE EQUIPMENT
- A47G29/00—Supports, holders, or containers for household use, not provided for in groups A47G1/00-A47G27/00 or A47G33/00
- A47G29/12—Mail or newspaper receptacles, e.g. letter-boxes; Openings in doors or the like for delivering mail or newspapers
- A47G29/122—Parts, details, or accessories, e.g. signalling devices, lamps, devices for leaving messages
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62C—FIRE-FIGHTING
- A62C2/00—Fire prevention or containment
- A62C2/06—Physical fire-barriers
- A62C2/065—Physical fire-barriers having as the main closure device materials, whose characteristics undergo an irreversible change under high temperatures, e.g. intumescent
Landscapes
- Health & Medical Sciences (AREA)
- Public Health (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Special Wing (AREA)
Abstract
A letterplate (1) comprises a pair of plastics frames (2, 3) that are adapted to be fined respectively one opposing sides (5, 6) of a door (4) and to inter-engage through a slot (5) cut into the door (4). Each frame (2, 3) is adapted to be secured directly to the door (4) via fasteners (14) and at least one of the frames (3) carries an intumescent seal (10) such that in use it will be disposed along at least one side of the slot (5) defined by the door (4). In addition, each of the fasteners (14) for at least one of the frames (3) is comprised of or is provided with a heat-insulating, non-flammable portion (15) disposed between a head (16) of the fastener (14) and the frame (3). In this way, if a fire occurs on one side of the door (4), the portions (15) reduce the flow of the heat between the heads (16) of the fasteners (15) and the adjacent plastics frame (3). This thereby protects the frame (3) and increases the time taken to allow the intumescent seal (10) to be fully deployed before the frame (3) is deformed by the heat and fails. Preferably, the heat-insulating, non-flammable portion comprises a washer disposed between a head of the fastener and the frame or a sleeve that covers the head of the fastener. It is also envisaged that the head of the fastener may be comprised of a heat-insulating, non-flammable material.
Description
A LETERPLATE
The present invention relates to a letterplate and, in particular to a fire-check letterplate.
Conventionally letterplates comprise a pair of inter-engaging plastics frames that are fitted together through both sides of a slot cut into a door of a building to accommodate same. The letterplate finishes the slot and provides one or more flaps and/or brushes to cover the framed slot and thereby protect the space on, for example an interior side of the door from the weather on the exterior side of the door whilst enabling letters and small packets to be pushed through the framed slot into the building.
In order to check fires, usually doors are made from i hour fire-rated materials. It is, however, important to prevent the framed slot through the letterplate from providing a conduit enabling air from the exterior of a building to fuel a fire arising within the building. To this end letterplates may be provided with an intumescent seal that can close the slot if the need arises. If this seal becomes sufficiently hot, for example in the case of a fire occurring on the interior side of the letterplate, then the seal is located and designed such that it swells sufficiently to close off the slot, thus cutting off the air supply to the fire that would otherwise be available through the slot.
The frames of letterplates may be metallic but they are more usually they are made of a plastics material. Such plastics letterplates are less expensive and easier to manufacture than metallic letterplates. However, they have the disadvantage that they tend not to be able to check a fire in the event of one breaking out in the interior of the building. Usually, the plastics of the frames melts and both of the frames fall away before an intumescent seal incorporated therein would have had sufficient time to operate. This enables air readily to pass through the slot in the door to fuel the fire.
The object of the present invention is to overcome or substantially mitigate the aforementioned problem.
According to the present invention there is provided a letterplate comprising a pair of plastics frames that are adapted to be fitted respectively one opposing sides of a door and to inter-engage through a slot cut into the door, each frame being adapted to be secured directly to the door via fasteners and at least one of the frames carrying an intumescent seal such that in use it will be disposed along at least one side of the slot defined by the door, characterized in that each of the fasteners for at least one of the frames is comprised of or is provided with a heat-insulating, non-flammable portion that is disposed at least between a head of the fastener and the frame.
It has been found that the main problem with conventional letterplates is that heat is transmitted to frames of the letterplate from a fire within a building along the fasteners used to attach the frames to the door.
The fasteners, typically being metal, heat up quickly and cause the plastics of the frame adjacent thereto to soften and deform. The frame is thereby loosened and tends to fall away from the door before the intumescent seal has had time to operate satisfactorily. However, in the present invention the heat-insulating, non-flammable portions are intended to reduce the flow of the heat between the heads of the fasteners and the adjacent frame. This thereby protects the plastics of the frame and increases the time taken before the frame falls away sufficiently to allow the intumescent seal to be fully deployed.
Preferably, the heat-insulating, non-flammable portion comprises either a washer disposed between a head of the fastener and the frame or a sleeve that covers the head of the fastener. Alternatively, the head of the fastener is comprised of a heat-insulating, non-flammable material.
Preferably also, said one frame with the fasteners provided with the heatinsulating, non-flammable portions is the frame adapted to be fitted to the exterior side of the door.
Usually, the frame on the interior side of the door is heated directly by the fire and will soften and deform quickly, well before the same can occur to the exterior frame. However, without the protective effect of the heat- insulating, non-flammable portions in accordance with the present invention, the exterior frame can also fall away before the intumescent seal can deploy. Positioning these portions on the exterior frame of the letterplate thereby increases the time available for the intumescent seal to operate satisfactorily to seal the slot in the door.
Preferably also, the portions are fashioned from magnesium silicate or calcium silicate board. Advantageously, the board is at least 3 mm thick.
Alternatively, the portions are comprised of a ceramic material.
Preferably also, four screw-fasteners are provided per frame.
Preferably also, both of the frames are adapted to carry the intumescent seal.
Preferably also, at least one of the frames is provided with a flap that is hinged along one side of the frame such that in use it hangs downwards to cover the slot in the door.
Preferably also, at least one of the frames is provided with a brush seal that in use covers the slot in the door.
An example of the present invention will now be described with reference to the accompanying drawings, in which:- Fig. 1 is a schematic cross-section through a letterplate according to the present invention when fitted through a slot formed in a door; and Fig. 2 is a view of the letterplate in the direction of the arrow II in Fig. i but with a flap thereof shown in a raised position.
As shown in the drawings, a letterplate 1 comprises a pair of rectangular frames 2, 3 that are adapted to be fitted respectively one opposing sides of a door 4 and to inter-engage through a rectangular slot 5 cut into the door 4. The frames 2, 3 cover the edges of the slot 5 and are designed primarily to protect the space on, for example an interior side 6 of the door 4 from the weather on the exterior side 7 of the door 4. Typically, the slot 5 will have dimensions of 253 mm X 47 mm and the internal slot of the letterplate 1 defined by the inter-engaging frames will have dimensions of 248 mm x42mm.
Each of the frames 2, 3 is made from a rigid plastics material, preferably by a moulding process. Each frame 2, 3 comprises a fascia portion 8 that is adapted to lie adjacent the respective side of the door 6, 7 and to be fastened thereto, as described below, and a series of supports 9 that are arranged at right angles to the fascia portion and that are adapted to project into the slot 5 cut into the door along its top and bottom sides. The dimensions of the frames 2, 3 are adapted such that the supports 9 of one of the frames 2 lie on the outside of the supports 9 of the other of the frames 3.
The supports 9 along the top and bottom of the frames 2, 3 carry intumescent seals io such that in use the seals io are retained in positions covering the top and bottom sides of the slot 5. Typically, the seals io are made from a graphite based material backed with glass scrim. They are designed to swell when heated sufficient to obturate the slot 5, thus significantly reducing the possible flow of air through the slot 5.
Each of the frames 2, 3 is also provided with a flap ii that is hinge along the uppermost side of the fascia portion 8 beneath a protecti overhang 12 such that in use it hangs downwards to cover the slot 5 in the door 4. The flaps ii are preferably made of aluminium and pivot outwardly of the door 4 to enable letters and small packets to be posted through the slot 5. Flaps ii may be provided on both sides of the door for aesthetic purposes but at least one flap 11 is preferably provided on the external side of the door fastened to the frame 3 to prevent wind and rain from passing through the slot. The exterior frame 3 is also provided with a brush seal 13 also covers the slot 5 in the door 4. Preferably, the brush seal 13 comprises a pair of brushes that overlap centrally of the slot 5. Such a seal reduces draughts through the slot while still enabling mail to be readily posted through the letter plate.
The frames 2, 3 are adapted to be directly secured to the respective sides 6, 7 of the door 4 by screw fasteners 14. Each frame 2, 3 is provided with a hole (not shown) at each of its four corners through which one of the screw fasteners 14 can pass. In this illustrated example, on at least the exterior frame 3, each of the screw fasteners 14 is provided with a heatinsulating, non-flammable washer 15 that is disposed between a head 16 of the fastener 14 and the frame 3. In this way, as described above, the passage of heat from the fastener 14 to the plastics of the frame 3 adjacent the head is slowed sufficiently to give time for the intumescent seals io to operate satisfactorily. The washers 15 can be made from any suitable material such as a ceramic material. However, from practicality and economics, the washers are preferably fashioned from magnesium silicate or calcium silicate board which is at least 3 mm thick.
In alternative embodiments of the invention, at least the heads 16 of the fasteners 14 can be covered by a protective, heat-insulating, nonflammable sleeve or coating (not shown). Alternatively, at least the head 16 of the fastener 14 may be comprised of a heat-insulating, nonflammable material. Such a fastener could be made in toto of this material if appropriate.
Claims (13)
1. A letterplate comprising a pair of plastics frames that are adapted to be fitted respectively one opposing sides of a door and to inter-engage through a slot cut into the door, each frame being adapted to be secured directly to the door via fasteners and at least one of the frames carrying an intumescent seal such that in use it will be disposed along at least one side of the slot defined by the door, characterized in that each of the fasteners for at least one of the frames is comprised of or is provided with a heat-insulating, non- flammable portion that is disposed at least between a head of the fastener and the frame.
2. A letterplate as claimed in Claim i, characterised in that the heatinsulating, non-flammable portion comprises a washer disposed between a head of the fastener and the frame.
3. A letterplate as claimed in Claim i, characterised in that the heatinsulating, non-flammable portion comprises a sleeve that covers the head of the fastener.
4. A letterplate as claimed in Claim 1, characterised in that the head of the fastener is comprised of a heat-insulating, non-flammable material.
5. A letterplate as claimed in any of Claims i to 4, characterized in that said one frame with the fasteners comprised of or provided with the heat-insulating, non-flammable portions is the frame adapted to be fitted to the exterior side of the door.
6. A letterplate as claimed in any of Claims 1 to 5, characterized in that the heat-insulating, non-flammable portions are fashioned from magnesium silicate or calcium silicate board.
7. A letterplate as claimed in Claim 6, characterized in that the board is at least 3 mm thick.
8. A letterplate as claimed in any of Claims i to 5, characterised in that in that the heat-insulating, non-flammable portions are comprised of a ceramic material.
9. A letterplate as claimed in any of Claims i to 8, characterized in that four screw-fasteners are provided per frame.
10. A letterplate as claimed in any of Claims i to 9, characterized in that both of the frames are adapted to carry the intumescent seal.
11. A letterplate as claimed in any of Claims 1 to 10, characterized in that at least one of the frames is provided with a flap that is hinged along one side of the frame such that in use it hangs downwards to cover the slot in the door.
12. A letterplate as claimed in any of Claims 1 to 11, characterized in that at least one of the frames is provided with a brush seal that in use covers the slot in the door.
13. A letterplate substantially as described herein and as shown in the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0511863A GB2426998B (en) | 2005-06-11 | 2005-06-11 | A letterplate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0511863A GB2426998B (en) | 2005-06-11 | 2005-06-11 | A letterplate |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0511863D0 GB0511863D0 (en) | 2005-07-20 |
| GB2426998A true GB2426998A (en) | 2006-12-13 |
| GB2426998B GB2426998B (en) | 2009-08-12 |
Family
ID=34855352
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0511863A Active GB2426998B (en) | 2005-06-11 | 2005-06-11 | A letterplate |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2426998B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2435074B (en) * | 2006-02-14 | 2010-01-06 | Window Fab & Fixing Supplies | Letter plate feature |
| GB2538045A (en) * | 2015-03-17 | 2016-11-09 | Uap Ltd | Improvements to letter-plates |
| CN107031935A (en) * | 2017-06-13 | 2017-08-11 | 何华勇 | A kind of security mailbox |
| GB2570750A (en) * | 2018-09-06 | 2019-08-07 | Rabinovitch Efim | A mail slot with security and insulation attachments |
| US11771254B2 (en) | 2020-09-29 | 2023-10-03 | Bota, Inc. | Mail slot insert with foam attachment |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10172492B2 (en) | 2015-01-15 | 2019-01-08 | Bota, Inc. | Adjustable insert for door mail slot |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4310500Y1 (en) * | 1966-12-28 | 1968-05-08 | ||
| GB2268224A (en) * | 1992-06-24 | 1994-01-05 | Mateer & Nelson Ltd | Letterplates |
-
2005
- 2005-06-11 GB GB0511863A patent/GB2426998B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4310500Y1 (en) * | 1966-12-28 | 1968-05-08 | ||
| GB2268224A (en) * | 1992-06-24 | 1994-01-05 | Mateer & Nelson Ltd | Letterplates |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2435074B (en) * | 2006-02-14 | 2010-01-06 | Window Fab & Fixing Supplies | Letter plate feature |
| GB2538045A (en) * | 2015-03-17 | 2016-11-09 | Uap Ltd | Improvements to letter-plates |
| GB2538045B (en) * | 2015-03-17 | 2020-06-10 | Uap Ltd | Improvements to letter-plates |
| CN107031935A (en) * | 2017-06-13 | 2017-08-11 | 何华勇 | A kind of security mailbox |
| GB2570750A (en) * | 2018-09-06 | 2019-08-07 | Rabinovitch Efim | A mail slot with security and insulation attachments |
| GB2570750B (en) * | 2018-09-06 | 2020-01-08 | Rabinovitch Efim | Security and insulation attachments for a mail slot |
| US11771254B2 (en) | 2020-09-29 | 2023-10-03 | Bota, Inc. | Mail slot insert with foam attachment |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0511863D0 (en) | 2005-07-20 |
| GB2426998B (en) | 2009-08-12 |
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