Electromagnetic door lock with visual indicator

Abstract

An electromagnetic door lock including: an electromagnet which can be energised and de-energised to put the lock into respective locked and unlocked conditions; a visual indicator which indicates the status of the lock; the visual indicator includes a light diffusing element and a light source is mounted internally of the light diffusing element; the light diffusing element is formed from silicone; and particles of a light reflective material are dispersed in the silicone.

Description

[0001] ELECTROMAGNETIC DOOR LOCK WITH VISUAL INDICATOR

[0002] Technical Field

[0003] The present invention relates to electromagnetic locks and particularly relates to improvements in illuminated visual indicators used on electromagnetic door locks to improve their appearance and visibility.

[0004] Background to the Invention

[0005] Referring to figure 1, an electromagnetic lock, magnetic lock, or maglock is a locking device that consists of an electromagnet 100 and an armature plate 120.

[0006] The principle behind an electromagnetic door lock is the use of electromagnetism to lock a door when energised. The electromagnet 100 is usually affixed to a fixed part of a doorway in a building and the armature 120 is affixed to a door to control access through the door as part of a building access or security system. When energised, the electromagnet 100 attracts the armature 120 with a force large enough to prevent the door from being opened.

[0007] A visual indicator is provided on the housing of the lock in the form of a transparent window 116 which is formed from glass or plastic. A light source is mounted inside the electromagnet 100. When the electromagnet is energised, the light source is illuminated. When the electromagnet is not energised, the light source turns off. The light from the light source can be seen through the transparent moulding 116.

[0008] The output of the visual indicator is an important safety feature and is the only indicator to building occupants for them to understand whether an electromagnetic door lock is “locked” or “unlocked. Often, the light emanating from the window 116 is difficult to recognise. This is particularly the case in low visibility conditions, such as in the case of a room or corridor which may be occupied by smoke. It can be difficult for occupants to properly see the indicator and to recognise whether they can open a door or not. There remains a need for improved electromagnetic door locks with improved visual indicators.

[0009] Summary of the Invention

[0010] In a first aspect the present invention provides an electromagnetic door lock including: an electromagnet which can be energised and de-energised to put the lock into respective locked and unlocked conditions; a visual indicator which indicates the status of the lock; the visual indicator includes a light diffusing element and a light source is mounted internally of the light diffusing element; the light diffusing element is formed from silicone; and particles of a light reflective material are dispersed in the silicone.

[0011] The light source may be is a point source LED which is mounted inside the light diffusing element.

[0012] The light diffusing element may be mounted at a comer region of a housing of the electromagnet and emits light from two surfaces of the housing.

[0013] The light source may be an LED strip which is mounted in a channel in the rear of the light diffusing element.

[0014] The light diffusing element may be mounted so that it extends horizontally across a surface of the housing of the electromagnet.

[0015] The particles of light reflective material may be formed from either aluminium oxide or titanium oxide.

[0016] Brief Description of the Drawings

[0017] An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0018] Figure 1 is perspective view of a prior art electromagnetic door lock;

[0019] Figure 2 is a rear lower perspective view of an electromagnetic door lock;

[0020] Figure 3 is a front lower perspective view of the lock of figure 2;

[0021] Figure 4 is an exploded view of the lock of figure 2;

[0022] Figure 5 is a detail view of the light diffuser and LED light source of the lock of figure 2;

[0023] Figure 6 is a rear perspective view of another embodiment of an electromagnetic door lock; and

[0024] Figure 7 is an exploded view of the lock of figure 6.

[0025] Detailed Description of the Preferred Embodiment

[0026] Embodiments of the invention are based on providing an electromagnet with a light diffusing element which is used in conjunction with a light source. The light diffusing element is formed from silicone and particles of a light reflective material are dispersed in the silicone.

[0027] The silicone light diffusing element of the present invention uses semitransparent or translucent silicone as the base material, with light-reflective powder uniformly distributed within. The particles of the powder can effectively scatter light, allowing light from the source to evenly spread throughout the diffuser, thereby achieving uniform illumination across the entire diffuser.

[0028] Referring to figures 2 and 3, an electromagnetic door lock 10 is shown including an electromagnet 14 which can be energised and de-energised to put the lock into respective locked and unlocked conditions. A visual indicator 20 which indicates the status of the lock is mounted at a comer of the housing and in use emits light at faces 15 and 16 of the housing 12.

[0029] Referring to figures 4 and 5, the visual indicator includes a light diffusing element in the form of diffuser 24 which in use is mounted in an opening 22 in the housing with the projecting portion 25 of the light diffusing element located in aperture 22. A light source in the form of a point source LED 26 is mounted internally of the diffuser 24 by being inserted into aperture 29. A cable 27 and connector 28 connects the LED 26 to the electronic circuit (PCB) 30 of the lock which is housed behind cover 32.

[0030] The LED may emit different colours to indicate the status of the lock. For instance, when illuminated green this may indicate that the lock is locked. When illuminated red this may indicate that the lock is unlocked (open). The installer of the lock can reverse the colour status by reversing the position of the connector 28 where it connects to the PCB.

[0031] The diffuser 24 may be formed according to the following process:

[0032] 1. A moulding mixture is prepared which is comprised of translucent silicone rubber with a shore hardness of A 50-70 and mixed with added reflective particles (0.2%wt), vulcanising agent (1.5%wt) and mold separator lubricant (0.5%wt).

[0033] 2. The mixture is injected into molds and cured.

[0034] 3. The cured silicone rubber is then ejected from the molds.

[0035] Suitable reflective particles include particles of titanium dioxide or particles of aluminium oxide with particle sizes in the range 0.1 to 10 micrometers.

[0036] Referring to figures 6 and 7, another embodiment of electromagnetic lock 10a is shown being labelled with like reference numerals. In the embodiment 10a, the visual indicator 20a extends horizontally across a surface of the housing 12a of the electromagnet.

[0037] The light diffuser 24a is formed with an open channel 29a at its rear. A strip LED module 26a is inserted into the channel 29a and connects to the PCB 30a by way of an electrical connector.

[0038] Electromagnetic locks fitted with light diffusers according to the method described above have been tested and achieve a high level of evenly distributed light output from the visual indicator of the lock which exceeds that of currently existing visual indicators.

[0039] Any reference to prior art contained herein is not to be taken as an admission that the information is common general knowledge, unless otherwise indicated.

[0040] Finally, it is to be appreciated that various alterations or additions may be made to the parts previously described without departing from the spirit or ambit of the present invention.

Claims

CLAIMS:

1. An electromagnetic door lock including: an electromagnet which can be energised and de-energised to put the lock into respective locked and unlocked conditions; a visual indicator which indicates the status of the lock; the visual indicator includes a light diffusing element and a light source is mounted internally of the light diffusing element; the light diffusing element is formed from silicone; and particles of a light reflective material are dispersed in the silicone.

2. An electromagnetic door lock according to claim 1 wherein the light source is a point source led which is mounted inside the light diffusing element.

3. An electromagnetic door lock according to claim 2 wherein the light diffusing element is mounted at a comer region of a housing of the electromagnet and emits light from two surfaces of the housing.

4. An electromagnetic door lock according to claim 1 wherein the light source is an LED strip which is mounted in a channel in the rear of the light diffusing element.

5. An electromagnetic door lock according to claim 4 wherein the light diffusing element is mounted so that it extends horizontally across a surface of the housing of the electromagnet.

6. An electromagnetic door lock according to any preceding claim wherein the particles of light reflective material are formed from either aluminium oxide or titanium oxide.

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