GB2547071B

GB2547071B - Lockable Electrical Switch Assembly

Info

Publication number: GB2547071B
Application number: GB1620120.4A
Authority: GB
Inventors: Patrick Harrison Philip
Original assignee: Phillip Patrick Harrison
Current assignee: Phillip Patrick Harrison
Priority date: 2015-11-30
Filing date: 2016-11-29
Publication date: 2019-08-28
Anticipated expiration: 2036-11-29
Also published as: GB201620120D0; GB2547071A8; GB201521051D0; GB2547071A

Description

LOCKABLE ELECTRICAL SWITCH ASSEMBLY

The present invention relates to a lockable electrical switch assembly requiring a mechanical actuation force. The invention particularly, though not exclusively, relates to such a lockable electrical switch assembly for preventing inadvertent or unauthorised opening and/or closing of an electrical circuit associated with mains lighting, mains power or standalone electrical appliances.

Electrical circuits within residential and commercial buildings are often controlled by manually operable switches. For example, switches of the rocker or toggle types are manually pivotable between an "on” position and an "off’ position so as to selectively control the energising of an associated electrical circuit. In certain circumstances it may be desirable to prevent an electrical switch from closing or opening an associated electrical circuit. For example, in a domestic environment, parents of young children may wish to lock any accessible electrical switches in their "off’ positions. Similarly, for safety and/or insurance reasons, it may be desirable to prevent the unauthorised use of electrical sockets and/or the operation of light switches by the general public in certain public spaces. Moreover, within commercial environments it may be crucial that certain electrical appliances - e.g. fridges or freezers containing perishable goods - are continuously powered.

It is already known to fit mechanical guards over moveable electrical switches to prevent, or at least inhibit, their unauthorised use. For example, United States patent No. 5,723,833 (Danny A. Thrasher) discloses a rigid cover member which, when closed over an underlying switch, urges it into its "off” position. The cover member is then padlocked to the housing thus making it impossible for the switch to be moved to its "on” position. Whilst effective in preventing unauthorised use of a switch, such a system is cumbersome, aesthetically undesirable, and costly.

An alternative arrangement is disclosed in United States patent publication No. 2014/0262710 (assigned to American Tack & Hardware, Co. Inc.) whereby a switch guard is secured over a conventional rocker switch. The switch guard is provided with two small slots to enable operation of the rocker switch only by passing a small item such as a coin or paperclip through the appropriate slot. This device is easily defeatable and hence has limited effectiveness in terms of preventing unauthorised use of a switch. Switch guards are often aesthetically undesirable and difficult to install since they require to be retrofitted to existing electrical switches.

It is of course known to provide key card systems commonly used in hotels to control door locks, lighting and electricity supplies with the principal aim of avoiding energy wastage. However, such systems typically require the key card to be seated within a single wall-mounted card holder in order to centrally and collectively power associated electrical circuits. Such systems are of no use in controlling individual mechanically operable electrical switches in domestic, commercial or public environments.

There is therefore a need for an alternative lockable electrical switch which overcomes, or at least ameliorates one or more of the aforementioned disadvantages.

According to a first aspect of the present invention there is provided a lockable electrical switch assembly comprising: (i) an insulated housing for containing electrical contacts associated with the lockable electrical switch; (ii) an actuator for transferring a manual operating force to open or close electrical contacts associated with the lockable electrical switch; and (iii) a locking assembly comprises an abutment member which is resiliently urged into physical engagement with a first bearing surface of the actuator within the insulated housing for automatically locking the actuator when it is in a predetermined position; wherein the actuator is mounted within the housing for movement between said predetermined position and at least one other position; and at least part of the locking assembly is operable from the exterior of the insulated housing to selectively unlock the actuator; and wherein the actuator and the abutment member are each provided with cooperable cam profiles.

In one embodiment (not described or illustrated), the abutment member is independently retractable to unlock the actuator without any physical interaction from outside the housing. For example, at least part of the abutment member may be formed from a ferromagnetic material such that a magnetic key brought into its proximity outside the housing provides a magnetic attraction force within the housing sufficient to overcome the resilient locking force and retract the abutment member away from the first bearing surface. It will be appreciated that the invention may be adapted to allow the use of alternative types of smart keys or proximity keys, for example employing radio pulse generators and antennas; RFID technology; biometric sensors and the like.

Optionally, the locking assembly comprises a locking detent which is resiliently urged into physical engagement with the abutment member within the housing.

Optionally, the abutment member comprises a locking surface and the locking detent is resiliently urged into physical engagement therewith.

Optionally, the locking detent and the abutment member are confined to linear pathways permitting their translational movement along non-parallel axes.

Preferably, the locking detent is confined to a linear pathway which extends substantially perpendicularly relative to a linear pathway of the abutment member.

Preferably, coil springs are interposed between surfaces of the housing and the locking detent and the abutment member respectively to effect said resilient urging.

As will be described in more detail below, the linear path for the locking detent is defined by a cylindrical channel formed in the moulded housing and extending away from its front face. The linear path for the abutment member is defined on one side by ribs or projections extending inwardly from the front face of the moulded housing and, on an opposite side, by a cover plate attached to the housing.

In the embodiment described and illustrated below, it will be appreciated that the aforementioned arrangement of technical features provides a switch which, by default, is locked in its "off” position. In particular, engagement of the locking detent within the locking surface of the abutment member retains the latter in its locking position until an external (and non-mechanical) unlocking force is applied from outside the housing.

Optionally, at least part of the locking detent is formed from a ferromagnetic material susceptible to a magnetic force originating externally of the housing.

Again, it will be appreciated that the invention may be adapted to allow the use of alternatives to magnetic keys which attract or repel the locking detent against the resilience of its coil spring. For example, other types of smart keys or proximity keys employing radio pulse generators and antennas; RFID technology, biometric sensors and the like may be employed.

Optionally, the actuator is a rocker switch or a toggle switch mounted on the housing for pivotable movement thereon.

It will be appreciated that the co-operable cam surfaces facilitate the smooth transfer of the actuator between its locked "off’ position and its unlocked "on” position.

Though principally described below in relation to rocker or toggle switches, it will be appreciated that, it its broadest sense, the present invention can also be applied to switches exhibiting other forms of movement, for example rotary switches and sliding switches.

According to a second aspect of the present invention there is provided a lockable electrical switch assembly kit comprising a lockable electrical switch assembly according to the first aspect, and a proximity device for remotely unlocking the switch assembly.

Optionally, the locking detent of the lockable electrical switch assembly is formed from, or coated with, a ferromagnetic material susceptible to influence by a magnetic force; and the proximity device is a magnetic key providing a magnetic field.

Alternatively, the locking assembly of the lockable electrical switch assembly is co-operable with a proximity device utilising one or more of RFID technology, biometric sensors, short-range radio transmitter technology, and magnetic or electric coupled transponder systems.

Further features and advantages of the present invention will become apparent from the appended claims and the following description.

Embodiments of the present invention will now be described by way of example only, with reference to the following diagrams, in which :-

Fig. 1 shows the facia of the lockable electrical switch of the present invention;

Fig. 2 shows the lockable electrical switch of the present invention whereby it is locked in its "off” condition;

Fig. 3 shows the locking detent following its non-mechanical retraction out of engagement with the locking surface of the abutment member;

Fig. 4 shows the movement of the rocker actuator to its "on” position and the consequent downwards movement of the abutment member; and

Fig. 5 shows the movement of the rocker actuator back to its "off” position and the consequent return of the abutment member and locking detent to their original locked positions. A lockable electrical switch assembly 10 according to the present invention is shown in Fig. 1. The illustrated embodiment shows a double gang switch. Since the structure and function of each gang is identical, only one is described below. It will be appreciated that the invention can be used in association with any gang arrangement. The assembly 10 comprises an insulated facia or housing 12 which separates a user from electrical contacts associated with an electrical circuit. As shown in Fig. 2, an actuator 14 in the form of a manually operable rocker (or toggle) switch is mounted within an aperture formed in the housing 12. The rocker switch 14 is pivotable relative to the housing in a rocking motion between at least two predetermined positions, namely an "on” position wherein electrical contacts associated with an electrical circuit are closed to energise the circuit; and an "off’ position wherein electrical contacts associated with an electrical circuit are opened to deenergise the circuit. A locking assembly 16, 18 is provided within the housing 12 for selectively locking the actuator in a predetermined position. In the illustrated example, the predetermined position is the aforementioned "off” position.

The locking assembly includes an elongate abutment member 16 extending along a path lying alongside and parallel to the front wall 12f of the housing 12. A lower distal end 16a of the abutment member 16 is separated from a lower flange or wall 12a of the housing 12 by a coil spring (not shown). An upper distal end 16b of the abutment member 16 is provided with a cam profile. As described in more detail below, different portions of the cam profile are engageable with different bearing surfaces of the rocker switch 14 dependent upon its pivotable orientation relative to the housing 12. In the particular arrangement shown in Fig. 2, an inclined locking portion 17a of the cam profile is urged vertically into physical engagement with a first bearing surface 14a on the rear of the rocker switch 14 to thereby lock it in the "off” position.

Translational movement of the abutment member 16 is confined to a vertical linear pathway extending between its coil spring and the rocker switch. The vertical linear pathway is defined, on one side, by ribs or protrusions 12p extending perpendicularly away from the rear surface of the front wall 12f of the housing 12 and, on the other side, by a cover plate 20 attached to the housing 12 for example by a screw. The cover plate 20 adopts a shallow U-shaped profile with a wide base and relatively short side walls. The cover plate 20 is orientated such that its base extends vertically and defines the rear limit of the vertical linear pathway. The shorter side walls of the cover plate 20 extend towards the front wall 12f of the housing. Shoulder surfaces 16s on the abutment member 16 are situated within the U-shaped profile between its upper and lower side walls. The side walls of the cover plate 20 therefore place a limit on the extent of upward and downward translational movement of the abutment member 16.

The locking assembly also includes a locking detent 18 located within a horizontal linear pathway proximate the front wall 12f of the housing 12 which extends perpendicularly relative to that of the abutment member 16. The locking detent 18 is cross-shaped in crosssection and its translational movement is confined to the pathway extending between its coil spring (not shown) and the abutment member 16. The horizontal linear pathway is defined by a cylindrical recess extending perpendicularly away from the front wall 12f of the housing 12.

The intersection of both pathways allows the locking detent 18 to physically engage with the abutment member 16 in the manner described in more detail below. A front distal end 18b of the locking detent 18 is separated from the front wall 12f of the housing 12 by a coil spring (not shown). A rear distal end 18a of the locking detent 18 is engageable within a locking recess 17b of the abutment member 16 dependent upon its translational position along its vertical linear pathway. In the particular arrangement shown in Fig. 2, the rear distal end 18a of the locking detent 18 is urged rearwardly away from the front wall 12f of the housing 12 into physical engagement with the locking recess 17b facing the fro nt-facing side of the abutment member 16.

In use, when the rocker switch 14 is pivoted into its "off’ position shown in Fig. 2 the abutment member 16 is urged vertically, by its coil spring, into its uppermost position along its vertical pathway. In doing so, the inclined locking portion 17a of the cam profile at its upper distal end 16a abuts the first bearing surface 14a on the rear of the rocker switch 14 and the locking recess 17b of the abutment member 16 is brought into alignment with the horizontal linear pathway of the locking detent 18. The locking detent 18 is urged, by its coil spring, away from the front wall 12f of the housing 12. Consequently, the rear distal end 18a of the locking detent 18 engages within the locking recess 17b whilst at least its front distal end 18b remains within the confines of its horizontal linear pathway.

When the locking detent 18 engages within the locking recess 17b of the abutment member, the rocker switch 14 is inevitably locked in its "off’ position. When locked by default in this manner, it will not be possible for an unauthorised person to unlock the switch assembly 10. In particular, manual pressure applied to the lower surface of the rocker switch 14 exteriorly of the housing 12 is resisted and will fail to pivot it to its "on” position because the abutment member 16 is prevented from moving vertically downwards by the presence of the locking detent 18 within its locking recess 17b. Furthermore, an unauthorised person will not perceive any means of tampering with the switch assembly 10 to override its default locking condition. In particular, there is an absence of any key slots or apertures extending through the housing 12 from its exterior to its interior.

In order to unlock the switch assembly 10, an external unlocking force must be applied from outside the housing 12. Importantly, since there is no physical access to the interior of the housing 12 from its exterior, unlocking of the locking assembly must be achieved at a distance by non-mechanical means.

In one embodiment, at least part of the locking detent 18 is formed from, or coated with, a ferromagnetic material susceptible to influence by a magnetic force originating externally of the housing 12. Unlocking of the locking assembly is therefore achieved by moving a magnetic "key" M into the proximity of the ferromagnetic locking detent 18 at the exterior of the magnetically transmissive housing 12. Crucially, the strength of the magnetic attraction force must be selected such that the magnetic field reaching the ferromagnetic locking detent 18 within the housing 12 is sufficient to overcome the resiliency of its associated coil spring. Once the rear distal end 18a of the locking detent 18 fully retracts from the locking recess 17b - as illustrated in Fig. 3 - there is no longer any means of preventing downwards movement of the abutment member 16 against the action of its associated coil spring.

For as long as the rear distal end 18a of the locking detent 18 remains outside the locking recess 17b, a manual force F applied to the lower surface of the rocker switch 14 exteriorly of the housing 12 will be capable of pivoting it to its "on” position. Pivoting of the rocker switch from its "off” position - shown in Fig. 3 - to its "on” position - shown in Fig. 4 - causes the first bearing surface 14a on the rear of the rocker switch 14 to ride upwards along the inclined locking portion 17a of the cam profile at the upper distal end 16b of the abutment member 16. Sufficient manual force F applied to the rocker switch 14 causes the abutment member 16 to be translated downwards along its vertical pathway and overcome the resiliency of its spring coil. In doing so, the locking recess 17b moves out of alignment with the horizontal linear pathway of the locking detent 18. Consequently, removal of the magnetic "key” M and its associated magnetic field from the proximity of the ferromagnetic locking detent 18 will not cause the locking assembly to lock the switch assembly in the "on” position. Instead, the ferromagnetic locking detent 18 will merely passively abut against a rear side surface of the abutment member 16 above the locking recess 17b as shown in Fig. 4.

Pivoting of the rocker switch from its "on” position - shown in Fig. 4 - to its "off” position -shown in Fig. 5 - causes the first bearing surface 14a on the rear of the rocker switch 14 to ride downwards along the inclined locking portion 17a of the cam profile at the upper distal end 16b of the abutment member 16. This movement of the rocker switch 14 allows the abutment member 16 to be translated upwards along its vertical pathway under the influence of its resilient spring coil. In doing so, the inclined locking portion 17a of the cam profile abuts against the first bearing surface 14a on the rear of the rocker switch 14 to lock it in the "off’ position. During the upward translational movement of the abutment member 16, the rear distal end 18a of the locking detent 18 rides long the rear side surface of the abutment member. Once the locking recess 17b of the abutment member 16 is once again brought into alignment with the horizontal linear pathway of the locking detent 18 its rear distal end 18a is urged, by its associated coil spring, into engagement with the locking recess 17b.

It will be appreciated that the lockable switching assembly and kit of the present invention provides a relatively simple and low cost means of mechanically preventing actuation of a rocker switch which overcomes or ameliorates problems associated with prior art devices.

Although a particular embodiment of the invention has been disclosed herein in detail, this has been done by way of example and for the purposes of illustration only. The aforementioned embodiment is not intended to be limiting with respect to the scope of the appended claims. It is contemplated by the inventor that various substitutions, alterations, and modifications may be made to the invention without departing from the scope of the invention as defined by the claims. It will also be appreciated that the descriptive terms vertical, horizontal, upper, lower, front and rear are not intended to be limiting in scope and are merely used to describe the orientation of the switch assembly illustrated in the figures.

For example, whilst the ferromagnetic locking detent 18 is retracted from its locking recess 17b by means of a magnetic attraction force, this could equally be achieved by an adapted arrangement using a magnetic repulsion force. It will be appreciated that the invention may be adapted to allow the use of alternatives to magnetic keys which attract or repel the locking detent against the resilience of its coil spring. For example, other types of smart keys or proximity keys employing radio pulse generators and antennas; RFID technology, biometric sensors and the like may be employed.

Claims

1. A lockable electrical switch assembly comprising: (i) an insulated housing for containing electrical contacts associated with the lockable electrical switch; (if) an actuator for transferring a manual operating force to open or close electrical contacts associated with the lockable electrical switch; and (nf) a locking assembly comprises an abutment member which is resiliently urged into physical engagement with a first bearing surface of the actuator within the insulated housing for automatically locking the actuator when it is in a predetermined position; wherein the actuator is mounted within the housing for movement between said predetermined position and at least one other position; and at least part of the locking assembly is operable from the exterior of the insulated housing to selectively unlock the actuator; and wherein the actuator and the abutment member are each provided with cooperable cam profiles.

2. A lockable electrical switch assembly according to claim 1, wherein part of the locking assembly is remotely operable and comprises a locking detent which is resiliently urged into physical engagement with the abutment member within the housing.

3. A lockable electrical switch assembly according to claim 2, wherein the abutment member comprises a locking surface and the locking detent is resiliently urged into physical engagement therewith.

4. A lockable electrical switch assembly according to claim 2 or 3, wherein the locking detent and the abutment member are confined to linear pathways permitting their translational movement along non-parallel axes.

5. A lockable electrical switch assembly according to any of claims 2 to 4, wherein the locking detent is confined to a linear pathway which extends substantially perpendicularly relative to a linear pathway of the abutment member.

6. A lockable electrical switch assembly according to any of claims 2 to 5, wherein coil springs are interposed between surfaces of the housing and the locking detent and the abutment member respectively to effect said resilient urging.

7. A lockable electrical switch assembly according to any of claims 2 to 6, wherein at least part of the locking detent is formed from a ferromagnetic material susceptible to a magnetic force originating externally of the housing.

8. A lockable electrical switch assembly according to any preceding claim, wherein the actuator is a rocker switch or a toggle switch mounted within the housing for pivotable movement thereon.

9. A lockable electrical switch assembly kit comprising a lockable electrical switch assembly according to any of claims 1 to 8; and a proximity device for remotely unlocking the switch assembly.

10. A lockable electrical switch assembly kit comprising a lockable electrical switch assembly according to any of claims 2 to 7; and a proximity device for remotely unlocking the switch assembly; wherein the locking detent of the lockable electrical switch assembly is formed from, or coated with, a ferromagnetic material susceptible to influence by a magnetic force; and the proximity device is a magnetic key providing a magnetic field.

11. A lockable electrical switch assembly kit according to claim 9, wherein the locking assembly of the lockable electrical switch assembly is co-operable with a proximity device utilising one or more of RFID technology, biometric sensors, short-range radio transmitter technology, and magnetic or electric coupled transponder systems.