Locking mechanism for electrical switching device

Abstract

A locking mechanism for an electrical switching device is provided, comprising: a cover configured to couple to the electrical switching device; and a slider disposed within the cover and moveable between a first stop position and a second stop position, wherein in the first stop position the slider protrudes from the cover by a first amount and wherein the second stop position the slider protrudes from the cover by a second amount greater than the first amount. When the electrical switching device is in an off state, the slider can be moved between the first and the second stop positions. When the slider is in the second stop position, the electrical switching device cannot be switched from the off state to an on state.

Description

[0001] Locking mechanism for electrical switching device

[0002] Field

[0003] This relates to an electrical switching device. In particular, this relates to a locking mechanism for an electrical switching device.

[0004] Background

[0005] An electrical switching device is provided to activate an electrical circuit when it is in an ON state and to deactivate an electrical circuit when it is in an OFF state.

[0006] An electrical switching device typically comprises a fixed contact and a moving contact. The moving contact may be movable by, for example, being coupled to a rotation shaft. Such an electrical switching device is in the ON state when the rotation shaft has been rotated such that the moving contact and the fixed contact are connected in an electrically conducting manner. The electrical switching device is in the OFF state when the rotation shaft has been rotated such that the moving contact and the fixed contact are separated in an electrically isolating manner.

[0007] To prevent the electrical circuit from being accidentally activated, it is required to provide a mechanism to lock the electrical switching device in the OFF state.

[0008] For example, electrical switching devices are typically provided within an enclosure comprising a door which enables access to the electrical switching device.

[0009] When the enclosure door is closed, the rotation shaft of the electrical switching device may extend through the enclosure door. An operating knob or handle may be provided at the end of the rotation shaft extending through the enclosure door to switch the electrical switching device between the ON and the OFF state. Additionally, when the enclosure door is closed, a locking mechanism, such as a padlock, is provided to lock the operating knob or handle. In this way the position of the rotation shaft is locked such that the electrical switching device is locked in the OFF state.

[0010] However, sometimes it is necessary to open the enclosure door, for example, for the purposes of maintenance. When the enclosure door is open, the operating knob or handle is disconnected from the rotation shaft, and therefore the state of the electrical switching device cannot be locked in this way. This presents a risk of electric shock to a user of the electrical switching device in the event that the electrical switching device is in, or is accidentally switched to, the ON state whilst the enclosure door is open.

[0011] Regulations, such as NFPA-79 2021, therefore mandate a provision to lock the electrical switching device even when the enclosure door is open. Further, the electrical switching device must only be locked in the OFF state.

[0012] It is therefore desirable to provide a locking mechanism for an electrical switching device which can couple to an electrical switching device within an enclosure, and which can only be locked when the switch is in the OFF state, to remove the possibility of inadvertently locking the electrical switching apparatus in the ON state.

[0013] Summary

[0014] A locking mechanism is provided as defined in the appended independent claim 1, with optional features defined in the dependent claims appended thereto.

[0015] In the following specification, a locking mechanism configured to couple to an electrical switching device in an enclosure and to enable the electrical switching device to be locked only in an OFF state is described.

[0016] According to an embodiment, a locking mechanism for an electrical switching device comprises a cover configured to couple to the electrical switching device and a slider disposed within the cover which is moveable between a first stop position and a second stop position. In the first stop position, the slider protrudes from the cover by a first amount and in the second stop position, the slider protrudes from the cover by a second amount greater than the first amount. When the electrical switching device is in an OFF state, the slider can be moved between the first and the second stop positions, and when the slider is in the second stop position, the electrical switching device cannot be switched from the OFF state to an ON state.

[0017] When the slider is in the first stop position, the electrical switching device can be freely switched between the ON and the OFF state.

[0018] When the electrical switching device is in the ON state, the slider cannot be moved between the first and the second stop positions.

[0019] As such, a locking mechanism with a simple mechanism may be provided to prevent an electrical switching device from accidentally being switched to the ON state. In particular, the slider provides a simple and robust locking mechanism. By using a locking mechanism in accordance with the embodiment, an electrical switching device with improved safety may be provided.

[0020] Optionally, the slider is configured to have an aperture through which a rotation shaft of the electrical switching device is inserted, the electrical switching device being switched between the ON and the OFF state by rotation of the rotation shaft.

[0021] The aperture of the slider is configured such that when the slider is in the first stop position, rotation of the rotation shaft is enabled, and, when the slider is in the second stop position, rotation of the rotation shaft is prevented.

[0022] The aperture of the slider is configured such that the slider can be moved to the second stop position only when the rotation shaft is in a position corresponding to the off state of the electrical switching device.

[0023] As such, a locking mechanism which is compatible with conventional electrical switching devices comprising rotation shafts may be provided. Further, by providing a locking mechanism with a simple configuration to control the rotation of a rotation shaft, a locking mechanism which can be easily adapted to different electrical switching devices and future needs may be provided. For example, the aperture can engage with the rotation shaft to prevent rotation, and this engagement can be modified or adapted to different electrical switching devices.

[0024] Optionally, when the slider protrudes by the second amount, a locking portion of the slider is exposed such that the electrical switching device can be locked in the OFF state. The locking portion is disposed within the cover when the slider protrudes by the first amount.

[0025] Optionally, the locking portion comprises an aperture configured to receive an external locking mechanism. Optionally, the external locking mechanism is a padlock.

[0026] When the slider is in the first stop position, the electrical switching device cannot be locked in either the ON or the OFF state.

[0027] This arrangement provides a locking mechanism which enables the electrical switching device to be locked in the OFF state. In addition, the locking mechanism ensures that it is only possible to lock the electrical switching device when it is in the OFF state, thereby preventing accidental locking of the electrical switching device in the ON state.

[0028] As such, a locking mechanism which complies with standard regulations and has improved safety may be provided.

[0029] Optionally, the slider is fixed to the cover by at least one snap lock. Optionally, the snap lock is provided on the cover. This arrangement ensures that the slider is securely fixed to the cover, thereby providing a locking mechanism with improved reliability.

[0030] Optionally, the cover comprises at least one rail along which the slider is configured to move. By guiding the motion of the slider in this way, a locking mechanism with improved operability may be provided. In particular, the slider is guided during operating in a reliable and repeatable manner. A robust locking mechanism can therefore be provided.

[0031] Optionally, an edge of the slider configured to engage with the rail is resiliently deformable. The slider can be resiliently deformable by form and / or by material.

[0032] Optionally, the edge comprises a compliant portion, the compliant portion having a peak protrusion configured to engage with the rail. The compliant portion can be compliant by form and / or by material.

[0033] Optionally, the peak protrusion is in a central portion of the edge.

[0034] By configuring the slider such that it has one or more of the above features, a slider with improved reliability and a unique shape profile which enables the slider to be seamlessly moved between predetermined (stop) positions within the cover may be provided. As such, a locking mechanism with improved operability may be provided.

[0035] Optionally, the rail comprises a first and second recessed portion, corresponding to the first and second stop position, and the peak protrusion of the slider is accommodated in the first and second recessed portion when the slider is in the first and second stop position respectively.

[0036] By configuring the rail in this way, the slider may be more securely held in the first or second stop positions. As such, a locking mechanism with improved reliability may be provided. Optionally, the first and second recessed portions have a shape corresponding to that of the peak protrusion. This arrangement may more securely hold the slider in the first and second stop positions, thereby further improving the reliability of the locking mechanism. The engagement of the recessed portions and the peak protrusion can therefore define the predetermined (stop) positions of the slider.

[0037] A locking mechanism comprising one or more of the above features provides a locking mechanism which uses a minimal number of components. As such, a locking mechanism which is quick and easy to assemble, has reduced manufacturing costs, and is easy to operate and maintain may be provided.

[0038] A system is also described herein comprising an electrical switching device and a locking mechanism as described herein. A cover of the locking mechanism is coupled to the electrical switching device.

[0039] Brief Description of the Drawings

[0040] Fig. 1 shows a front view of the exterior of the locking mechanism according to an embodiment when the slider is in the first stop position.

[0041] Fig. 2 shows a front view of the exterior of the locking mechanism according to an embodiment when the slider is in the second stop position.

[0042] Fig. 3 shows a front view of the interior of the locking mechanism according to an embodiment when the slider is in the first stop position.

[0043] Fig. 3A shows a schematic view of an aperture of the slider.

[0044] Fig. 4 shows a front view of the interior of the locking mechanism according to an embodiment when the slider is in the second stop position.

[0045] Fig. 5 shows a side view of the exterior of the locking mechanism according to an embodiment when the slider is in the second stop position.

[0046] Fig. 6 shows a perspective view of an edge of the slider according to an embodiment.

[0047] Detailed Description

[0048] Embodiments of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the present disclosure are shown. The same reference numbers indicate the same components throughout the specification.

[0049] This disclosure may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0050] It will be understood that, although the terms "first", "second," etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are labels, and are only used to distinguish one element from another element. For instance, a first element discussed below could be termed a second element without departing from the teachings of the present disclosure. Similarly, the second element could also be termed the first element.

[0051] With reference to Figures 1 to 6, a locking mechanism is described. The locking mechanism is configured to couple to an electrical switching device (not shown) in an enclosure and to enable the electrical switching device to be locked only in an OFF state.

[0052] The locking mechanism comprises a cover 100 and a slider 200. The cover 100 is configured to couple to the electrical switching device, in particular is configured to couple such that the slider can engage with an actuator / rotation shaft of a main switch of the electrical switching device.

[0053] The slider 200 is disposed inside the cover 100 and is moveable between a first stop position SI and a second stop position S2, shown in Figures 3 and 4 respectively.

[0054] The slider 200 is configured such that it is movable between the first stop position SI and the second stop position S2 when the electrical switching device is in the OFF state. The slider 200 is configured such that the electrical switching device cannot be switched from the OFF state to the ON state when the slider 200 is in the second stop position S2. An example mechanism by which this is achieved is described below.

[0055] The slider 200 is configured such that it cannot be moved from the first stop position SI to the second stop position S2 when the electrical switching device is in the ON state. The slider 200 is configured such that the electrical switching device can be freely switched between the ON state and the OFF state when the slider is in the first stop position SI. An example mechanism by which this is achieved is described below.

[0056] As such, a locking mechanism with a simple mechanism to prevent an electrical switching device from accidentally being switched to the ON state may be provided. By using a locking mechanism in accordance with the embodiment, an electrical switching device with improved safety may be provided.

[0057] According to the embodiment, the electrical switching device comprises a switch comprising a moving contact and a fixed contact (not shown). The switch can be turned ON or OFF by rotation of a rotation shaft 300 which is indirectly coupled at one end to the moving contact through a switching mechanism (not shown).

[0058] The electrical switching device further comprises an external handle or knob (not shown) coupled to an opposite end of the rotation shaft 300. In other words, the rotation shaft 300 is coupled between the switching mechanism and the external handle or knob. The external handle / knob can be outside a panel or enclosure containing the electrical switching device; in this example, the cover 100 is coupled to an external surface of said panel or enclosure, and the shaft 300 is disposed through the external surface of the panel / enclosure to reach the switching mechanism within the panel / enclosure. The handle / knob is configured to connect or separate the moving and the fixed contact (i.e. to operate the switching mechanism of the switch) via the shaft 300. For example, the shaft can be coupled between the handle / knob and a bridge (or other component) of the switching mechanism, such that the moving contact can be moved and connected to or separated from the fixed contact of the switch by rotation of the rotation shaft 300. As such, by rotation of the rotation shaft 300 as a result of user engagement with the knob / handle, the electrical switching device can be switched between the ON state and the OFF state.

[0059] The slider 200 comprises an aperture 210 through which the rotation shaft 300 of the electrical switching device, in particular an end of the rotation shaft, is inserted or disposed. The aperture 210 may comprise a first portion 210a, here corresponding to an upper portion of the aperture 210, and a second portion 210b, here corresponding to a lower portion of the aperture. The second portion 210b is narrower than the first portion 210a.

[0060] An example shape of the aperture 210 is shown schematically in Fig. 3A. In particular, Fig. 3A shows the first portion 210a being wider than the second portion 210b. In this specific example the aperture is substantially key-hole shaped, but any suitable shape or configuration can be provided to fulfil the functionality described herein. In some examples, the aperture may be rotated such that a lower portion is wider than the upper portion. The shape of the aperture can depend on the positions of the first and second stop positions SI, S2. In this specific example, when the slider 200 is in the first stop position SI, the rotation shaft 300 is inserted into / disposed through the (wider) first portion 210a. When the slider 200 is in the second stop position S2, the rotation shaft 300 is inserted into / disposed through the (narrower) second portion 210b.

[0061] The first portion 210a is configured to have a width greater than the diameter of the rotation shaft 300. In the embodiment shown in Figures 3 and 4, the first portion 210a has a substantially round shape, however it is not limited thereto. For example, the first portion 210a may have a substantially rectangular shape.

[0062] The second portion 210b is configured to have a width substantially equal to the diameter of the rotation shaft 300. In the embodiment shown in Figures 3 and 4, the second portion 210b has a substantially rectangular shape, however it is not limited thereto. For example, the second portion 210b may have a substantially round shape.

[0063] The slider 200 comprises a first edge 211 surrounding the first portion 210a of the aperture 210 and a second edge 212 surrounding the second portion 210b of the aperture 210. The slider 200 further comprises a third edge 213 connecting the first edge 211 and the second edge 212. The third edge 213 protrudes inwards from the first edge 211 towards the second edge 212.

[0064] The rotation shaft 300 comprises a protrusion 310. The protrusion 310 protrudes from the circumferential edge of the rotation shaft 300. The protrusion 310 protrudes from the end of the rotation shaft 300 which is inserted into the aperture 210. The protrusion 310 may be formed integrally with the rotation shaft 310, but it is not limited thereto.

[0065] The rotation shaft 300 is configured such that, when the electrical switching device is in the OFF state, the protrusion 310 protrudes from the rotation shaft 300 in a direction parallel to the direction in which the slider 200 moves between the first stop position SI and the second stop position S2. In the present example, the direction in which the slider 200 moves between the first stop position SI and the second stop position S2 corresponds to the vertical direction, but it is not limited thereto.

[0066] The rotation shaft 300 is configured such that, when the electrical switching device is in the ON state, the protrusion 310 protrudes from the rotation shaft 300 in a direction perpendicular to the direction in which the slider 200 moves between the first stop position SI and the second stop position S2.

[0067] The protrusion 310 is configured such that the distance between the circumferential edge of the rotation shaft 300 and an outer edge of the protrusion is less than the distance between the circumferential edge of the rotation shaft 300 and the first edge 211 of the aperture 210. As such, the rotation shaft 300 can be freely rotated within the first portion 210a because there is no interference between the protrusion 310 and the slider 200. As such, the electrical switching device can be freely switched between the ON and the OFF states when the slider 200 is in the first stop position SI.

[0068] The protrusion 310 is configured such that the distance between the circumferential edge of the rotation shaft 300 and the outer edge of the protrusion 310 is greater than the distance between the circumferential edge of the rotation shaft 300 and the second edge 212 of the aperture 210. As such, when the rotation shaft 300 is in a position corresponding to the ON state of electrical switching device, the protrusion 310 and the third edge 213 interfere when the slider 200 moves from the first stop position SI to the second stop position S2. As such, the slider 200 cannot be moved from the first stop position SI to the second stop position S2 when the electrical switching device is in the ON state.

[0069] Similarly, when the rotation shaft 300 is rotated from a position corresponding to the OFF state of the electrical switching device towards a position corresponding to the ON state, the protrusion 310 interferes with the third edge 213 of the aperture 210 when the slider 200 is in the second stop position S2, preventing the rotation shaft 300 from moving to the position corresponding to the ON state. As such, when the slider 200 is in the second stop position S2, the electrical switching device cannot be turned ON.

[0070] In other examples (not shown) the aperture 210 of the slider may comprise one or more protrusions that engage with the rotation shaft 300 to allow / prevent rotation of the shaft 300 (i.e. in place of protrusion 310). Alternatively, any other geometry or configuration of the slider 200 can be provided such that the shaft 300 can be rotated as described herein and such that the slider 200 is movable between the first stop position SI and the second stop position S2 when the electrical switching device is in the OFF state but cannot be moved from the first stop position SI to the second stop position S2 when the electrical switching device is in the ON state. A locking mechanism comprising a simple configuration to control the rotation of a rotation shaft 300 in the form of an aperture 210 is thus provided. As such, the locking mechanism may be easily adapted to different electrical switching devices and future needs.

[0071] A locking portion 220 of the slider 200 will now be described.

[0072] Figures 1 and 3 show the slider 200 in the first stop position SI in the cover 100.

[0073] The slider 200 is configured to protrude from the cover 100 by a first amount DI when it is in the first stop position SI. The slider 200 may be configured to protrude from the cover 100 in a vertically upwards direction as shown, however it is not limited thereto. The slider can protrude from the cover in any suitable direction. Optionally the direction is perpendicular to an axis of rotation of the shaft 300.

[0074] Figures 2 and 4 show the slider 200 in the second stop position S2 in the cover 100.

[0075] The slider 200 is configured to protrude from the cover 100 by a second amount D2 when it is in the second stop position S2. The second amount D2 is greater than the first amount DI.

[0076] According to the embodiment, the slider 200 comprises a locking portion 220. The slider 200 is configured such that the locking portion 220 is exposed when the slider 200 protrudes from the cover 100 by the second amount D2, that is, when the slider 200 in the second stop position S2. The locking portion 220 is configured to enable the position of the slider 200, and therefore the state of the electrical switching device, to be locked.

[0077] As shown in Figure 5, the locking portion 220 may comprise an aperture 220a configured to receive an external locking mechanism, such as a padlock. However, it is not limited thereto and any suitable means of locking the position of the slider 200 in the second stop position may be applied.

[0078] When the slider 200 is in the first stop position SI and protrudes from the cover 100 by the first amount SI, the locking portion 220 is disposed within the cover 100. That is, the locking portion 220 is not exposed when the slider 220 is in the first stop position SI. As such, the position of the slider 200 cannot be locked when it is in the first stop position SI, when the electrical switching device can freely switch between the ON and the OFF state. That is, the state of the electrical switching device cannot be locked when the slider 200 is in the first stop position SI. The position of the slider 200 can be locked when it is in the second stop position S2, when the electrical switching device is in the OFF state.

[0079] As such, the electrical switching device can be locked when the slider 200 is in the second stop position S2, when the electrical switching device is in the OFF state. Further, it is only possible to lock the electrical switching device when the slider 200 is in the second stop position S2, when the electrical switching device is in the OFF state. As such, accidental locking of the electrical switching device in the ON state is prevented, thereby improving the safety of the electrical switching device.

[0080] Next, the arrangement of the slider 200 within the cover 100 will be described.

[0081] The slider 200 is securely fixed to the cover 100 by a snap lock 110. The snap lock 110 may be provided on the cover 100. The snap lock 110 may be provided to fix an edge 230 of the slider 200 to the cover 100. The cover 100 may comprise a plurality of snap locks 110. As shown in the examples of Figures 3 and 4, the slider may be fixed to the cover with snap locks on either side of the slider (i.e. there are two edges, each of which is snapped to the cover). The snap lock(s) 110 ensures that the slider 200 is securely fixed to the cover 100, thereby providing a locking mechanism with improved reliability.

[0082] As set out above, the slider 200 is movable between the first stop position SI and the second stop position S2. The slider 200 may be moved, for example, by a user applying a force to a portion of the slider 200 protruding from the cover 100.

[0083] The cover 100 includes a rail 120 along which the slider 200 is configured to move. In particular, an edge 230 of the slider 200 is guided along the rail 120. As discussed above, an edge 230 on each side of the slider 200 can be guided along respective rails. The cover 100 may comprise a plurality of rails along which a plurality of edges of the slider 200 are configured to move along. The use of a plurality of rails can improve the stability of motion of the slider during operation, by guiding each edge of the slider between the stop positions SI, S2. The edge 230 of the slider 200 configured to move along the rail 120 is optionally resiliently deformable. The (optionally each) edge can be resiliently deformable by material and / or form. For example, the edge 230 of the slider 200 may be made of a material such as plastic and be resilient by form. This resiliency may improve the reliability of the slider 200 and thereby the locking mechanism by facilitating repeatable operation and movement of the slider.

[0084] The edge 230 (optionally each edge) of the slider 200 optionally comprises a compliant portion 231. The compliant portion 231 has a peak protrusion 231a configured to engage with the rail 120. The peak protrusion 231a is formed in a central portion of the edge 230. However, the peak protrusion 231a is not limited thereto, and may be formed at another position along the edge 230.

[0085] The resiliently deformable / compliant portion 231 of the edge 230 is configured to gradually protrude outwards from a first end 230a of the edge 230 to the peak protrusion 231a and to gradually recess inwards from the peak protrusion 231a towards a second end 230b of the edge 230. As such, a slider 200 with a unique shape profile may be provided, which enables the slider 200 to be seamlessly and reliably moved within the cover 100. As such, a locking mechanism with improved operability may be provided.

[0086] The rail 120 comprises a first recessed portion 121 and a second recessed portion 122. The first recessed portion 121 and the second recessed portion 122 correspond to the first stop position SI and the second stop position S2 in the cover 100 respectively. In particular, when the slider is in the first stop position SI or the second stop position S2, the peak protrusion 231a is accommodated in the first recessed portion 121 or the second recessed portion 122 respectively.

[0087] The first recessed portion 121 and the second recessed portion 122 are configured to have a shape corresponding to the peak protrusion 231a.

[0088] The first and second recessed portions 121, 122 may securely hold the slider 200 in the first and second stop positions SI, S2, thereby improving the reliability of the locking mechanism.

[0089] The configuration of the compliant portion 231 and the rail 120 is not limited to the above-described embodiment. For example, the compliant portion may comprise a plurality of peak portions, and the first and second recessed portions may each comprise a corresponding number of accommodating recessed portions. The recessed portions may also have a shape which can accommodate the peak protrusions, without having a corresponding shape.

[0090] A locking mechanism comprising one or more of the above-described features provides a locking mechanism which uses a minimal number of components. As such, a locking mechanism may be provided which is quick and easy to assemble, has reduced manufacturing costs, and is easy to operate and maintain.

[0091] The above-described locking mechanism may be coupled to an electrical switching device provided within an enclosure. As such, the electrical switching device can be locked in the OFF state even when the enclosure door is open. Therefore, a locking mechanism compliant with various safety regulations may be provided.

[0092] List of reference numerals

[0093] 100 cover

[0094] 120 rail

[0095] 200 slider

[0096] 210 aperture

[0097] 210a first portion

[0098] 210b second portion

[0099] 211 first edge

[0100] 212 second edge

[0101] 213 third edge

[0102] 220 locking portion

[0103] 220a aperture

[0104] 230 edge

[0105] 230a first end of the edge

[0106] 230b second end of the edge

[0107] 231 compliant portion

[0108] 231a peak protrusion

[0109] 300 shaft

[0110] 310 protrusion

[0111] DI first amount

[0112] 51 first stop position

[0113] 52 second stop position

Claims

1. Claims1. A locking mechanism for an electrical switching device, comprising: a cover configured to couple to the electrical switching device; and a slider disposed within the cover and moveable between a first stop position and a second stop position, wherein in the first stop position the slider protrudes from the cover by a first amount and wherein the second stop position the slider protrudes from the cover by a second amount greater than the first amount; wherein, when the electrical switching device is in an OFF state, the slider can be moved between the first and the second stop positions, and wherein, when the slider is in the second stop position, the electrical switching device cannot be switched from the OFF state to an ON state.

2. The locking mechanism of claim 1, wherein, when the slider is in the first stop position, the electrical switching device can be freely switched between the ON and the OFF state.

3. The locking mechanism of claim 1 or 2, wherein, when the electrical switching device is in the ON state, the slider cannot be moved between the first and the second stop positions.

4. The locking mechanism of claim 1, wherein the slider is configured to have an aperture through which a shaft of the electrical switching device is inserted, the electrical switching device being switched between the ON and the OFF state by rotation of the shaft.

5. The locking mechanism of claim 3, wherein the aperture of the slider is configured such that when the slider is in the first stop position, rotation of the shaft is enabled, and, when the slider is in the second stop position, rotation of the shaft is prevented.

6. The locking mechanism of claim 3, wherein the aperture of the slider is configured such that the slider can be moved to the second stop position only when the shaft is in a position corresponding to the OFF state of the electrical switching device.

7. The locking mechanism of claim 1, wherein, when the slider protrudes by the second amount, a locking portion of the slider is exposed such that theelectrical switching device can be locked in the OFF state, wherein the locking portion is disposed within the cover when the slider protrudes by the first amount.

8. The locking mechanism of claim 6, wherein, the locking portion comprises an aperture configured to receive a locking mechanism, optionally wherein the locking mechanism is a padlock.

9. The locking mechanism of claim 6 or 7, wherein, when the slider is in the first stop position, the electrical switching device cannot be locked in either the ON or the OFF state.

10. The locking mechanism of claim 1, wherein the slider is fixed to the cover by at least one snap lock, optionally provided on the cover.

11. The locking mechanism of claim 1, wherein the cover comprises at least one rail along which the slider is configured to move.

12. The locking mechanism of claim 11, wherein an edge of the slider is configured to engage with the rail, wherein at least part of the edge is resiliently deformable.

13. The locking mechanism of claim 12, wherein at least part of the edge comprises a compliant portion, the compliant portion having a peak protrusion configured to engage with the rail, optionally wherein the peak protrusion is in a central portion of the edge.

14. The locking mechanism of claim 12 or 13, wherein the rail comprises a first and second recessed portion, the first and second recessed portions corresponding to the first and second stop positions, respectively, and wherein the peak protrusion of the slider is accommodated in the first and second recessed portion when the slider is in the first and second stop position respectively.

15. The locking mechanism of claim 14, wherein the first and second recessed portions have a shape corresponding to that of the peak protrusion.

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