GB2510097A

GB2510097A - Door with switchable window having selective transparency

Info

Publication number: GB2510097A
Application number: GB1219956.8A
Authority: GB
Inventors: David Rory Charles Batt
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-11-06
Filing date: 2012-11-06
Publication date: 2014-07-30
Also published as: GB201219956D0

Abstract

A door includes a panel 10 having a window aperture in which a window 11 is fitted. The window comprises a material (13, fig 2) which is normally configured in a first state to partially or fully obscure vision through the window. The door further comprising means, such as a control unit 19, for reconfiguring or switching the window into a second state, in which vision through the window is unobstructed. The said material of the window is preferably liquid crystal, such as PDLC. The operation of the window is preferably configured to prevent or deter actuation by persons other than in the event of a fire or other emergency. Preferably the window is reconfigured by an actuator 21, optionally comprising a key switch, keypad or breakable cover.

Description

DOORS

This invention relates to doors and the like.

Fire doors are doors which have a resistance to fire. Many countries have regulations, which dictate that certain doors on a building must be fire doors in order to control the spread of fire. Fire doors generally have to be kept shut or are provided with a release mechanism, which closes the door in the event that a fire alarm is activated.

A disadvantage of any closed door is that it is not possible to see the area on the other side of the door without opening it. Thus, upon arrival at the scene of the fire, a fire fighter has to open any closed door in order to determine the extent of the tire behind the closed door. A disadvantage of this is that opening the door of a closed room re introduces oxygen into the room and fuels the combustion, perhaps explosively. This effect is known as a backdraft or a flashover and poses a serious risk to fire fighters.

In order to solve this problem it is known to fit some tire doors with windows, so that fire fighters can see through the door without opening it. However, a disadvantage of providing a window is that it reduces the privacy of persons using the room, for example in toilets, bathrooms and operating theatres etc. Windows also have the effect of allowing thieves to see the contents of a secure room.

Many doors are not provided with a window for privacy reasons. However, there is often the need to be able to see through such doors, for example to determine the identity of person standing on the other side of the door. Typically, this has been achieved by providing a peep hole in the door. However, a disadvantage of such peep holes is that they have a limited field of view.

We have now devised a door which alleviates the above mentioned problems.

In accordance with this invention, there is provided a door comprising a door panel having a window aperture in which a window is fitted, the window comprising a material which is normally configured in a first state to partially or fully obscure vision through the window, door further comprising means for re-configuring the window into a second state in which vision through the window is substantially unobstructed.

In use, the window is normally opaque and hence the door does not compromise the privacy within a room which is closed by the door. In order to see through the door, for example in the event of a tire or when someone wishes the door to be opened, the window can be reconfigured to allow vision through the door without opening it.

Preferably the re-configuration means comprises an actuator, which can be actuated to re-configure the window from said first to said second state.

Preferably the actuator is disposed on a front face of the door panel.

Preferably the actuator is configured to prevent or deter actuation by persons other than in the event of a fire or other emergency.

The actuator may comprise a key switch which is only operable by persons holding the key, a keypad which is only operable by persons knowing the code, or a cover which has to be broken by persons in the event of a fire.

Preferably the material is changed from said first to said second states by changing an electrical signal applied to the material.

Preferably the material comprises a liquid crystal, such as a particle disbursed liquid crystal (PDLC).

Preferably the material is configured in the second state by applying a voltage to the material which is higher than the voltage used to configure the material in the first state.

Preferably the door comprises a control unit for generating the signal required to change the state of the material.

Preferably the control unit is contained in a recess or cavity formed in the door panel.

In one embodiment, the door comprises a battery which delivers power to the control unit. The battery is preferably contained in a recess or cavity formed in the door panel.

Preferably the control unit comprises a fire retardant enclosure.

In an alternative embodiment, the door comprises a contact or wire which delivers power from a structure to which the door is mounted.

Preferably the control unit is arranged to apply an AC voltage in excess of 50 volts to the material, the AC voltage being generated from a low voltage DC power supply: in this manner, any risks associated with applying a voltage in excess of 50 volts AC to the door are elevated.

Preferably the material comprises a panel which is disposed between layers of glass.

An embodiment of the present invention will now be described by way of example only and with reference to accompanying drawings, in which: Figure 1 is a front view of a fire door in accordance with the present invention; and Figure 2 is a sectional view along the line II -II of Figure 1.

Referring to the drawings, there is shown a fire door comprising a traditional fire door panel 10 having a fire retardant construction of the type which will be known to those skilled in the art. The door panel 10 comprises a window aperture in which a window 11 is fitted. The window 11 comprises a sheet of toughened glass 12 which is bonded to a PDLC panel 13 by an adhesive 14. The opposite side of the PDLC panel 13 is bonded to a sheet of fire rated glass 15 by an adhesive 16.

The door is hinged along one side thereof to a frame 17 by hinges 18. A control unit 19 is recessed into the hinged side edge of the door panel 10. The control unit 19 comprises a fire retardant housing. A 9-volt battery 20 is also recessed into the hinged side edge of the door panel 10. An actuator 21 is mounted on the front/rear face of the door panel 10. The actuator 21 and battery 20 are connected to the control unit 19 by wires which extend inside the door panel 10. The control unit 19 is connected to the PDLC panel 13 of the window 11 by a wire which also extends inside the door panel 10. The actuator 21 may comprise a key switch or it may comprise a switch which is normally disposed behind a sheet of glass that has to be broken in order to actuate the switch.

The PDLC panel comprises two outer layers of polyester material and a central layer of liquid crystal. Under normal circumstances, where no power is applied to the PDLC panel 13, the crystals are arranged irregularly and make the panel opaque.

Upon the application of an AC voltage to the panel 13, the crystals align and make the panel 13 transparent.

Under normal circumstances, no power is applied to the PDLC panel 13 and hence the window 13 is opaque. In the event of a fire, the actuator is actuated by a fire fighter, so that the control unit 19 draws power from the battery 20 and generates a volt AC signal which is applied to the FDLC panel to make the window 13 substantially transparent. In this manner, a fire fighter is able to see through the door to determine the extent of any fire on the other side.

In an alternative embodiment, the battery 20 is omitted and the control unit 19 draws power from a power supply located externally to the door. In order to achieve this, the door panel 10 may comprise electrical terminals which makes contact with complementary terminals on the door frame 17.

Additional features of the invention could include lights, door bells and door access systems which are integrated into the door and powered internally within the door structure directly from the battery or other power source. The window 11 may also be configured so that vision is only enabled in one only direction, so that persons on the other side of the door are unaware that they are being viewed.

A fire in accordance with the present invention is simple and expensive in construction yet allows persons to see through the door when desired, whilst preventing vision through the door under normal circumstances.

Claims

Claims 1. A door comprising a door panel having a window aperture in which a window is fitted, the window comprising a material which is normally configured in a first state to partially or fully obscure vision through the window, the door further comprising means for re-configuring the window into a second state in which vision through the window is substantially unobstructed.
2. A door according to claim 1, wherein the re-configuration means comprises an actuator, which can be actuated to re-configure the window from said first to said second state.
3. A door according to claim 2, wherein the actuator is disposed on a front face of the door panel.
4. A door according to claim 2 or claim 3, wherein the actuator is configured to C") prevent or deter actuation by persons other than in the event of a fire or other emergency. r

1
5. A door according to any one of claims 2 to 4, wherein the actuator comprises a key switch which is only operable by persons holding the key, a keypad which is only operable by persons knowing the code, or a cover which has to be broken by persons in the event of a fire.
6. A door according to any preceding claim, wherein the material is changed from said first to said second states by changing an erectrical signal applied to the material.
7. A door according to claim 6, wherein the material is configured in the second state by applying a voltage to the material which is higher than the voltage used to configure the material in the first state.
8. A door according to any preceding claim, wherein the material comprises a liquid crystal.
9. A door according to any preceding claim, further comprising a control unit for generating the signal required to change the state of the material.
10. A door according to claim 9, wherein the control unit is contained in a recess or cavity formed in the door panel.
11. A door according to claim 9 or claim 10, wherein the door comprises a battery which delivers power to the control unit.
12. A door according to claim 11, wherein the battery is contained in a recess or cavity formed in the door panel.
13. A door according to any one of claims 9 to 12, wherein the control unit comprises a tire retardant enclosure.
14. A door according to claim 9 or claim 10, wherein the door comprises a contact or wire which delivers power from a structure to which the door is mounted.
15. A door according to claim 14, wherein the control unit is arranged to apply an C') AC voltage in excess of 50 volts to the material, the AC voltage being generated from a low voltage DC power supply. r
16. A door according to any preceding claim, wherein the material comprises a panel which is disposed between layers of glass. r
17. A door substantially as hereinbefore described and as illustrated in the accompanying drawings.