Patent Description:
Switchgears and other switching devices are used to control and protect electrical equipment, such as equipment operated by utilities, commercial building owners, and operators of distributed renewable generation assets such as solar farms and wind turbines. Such switchgears include various medium voltage devices (e.g., devices rated for 12kV or 24kV) for a range of applications, such as a ring main unit (RMU). Other switching devices include, for example, vacuum circuit breakers (VCBs).

For any given equipment specification or application, it is desirable to provide a reliable and compact device with a small footprint. It is also desirable to provide an actuating mechanism with a small footprint.

Document <CIT> discloses a switching device comprising a plurality of switching mechanisms configured to connect and disconnect a power supply from a load, the plurality of switching mechanisms arranged along a first axis defining a first direction and each comprising a fixed contact and a moveable contact; and an actuating mechanism for simultaneously actuating the plurality of switching mechanisms, the actuating mechanism comprising a bridge configured to move the movable contacts of the plurality of switching mechanisms; a shaft arranged along a rotational axis, wherein the shaft is configured to rotate around the rotational axis; and one or more force transmittal mechanisms configured to convert torque from the rotation of the shaft to a linear force acting on the bridge in a second direction, wherein movement of the bridge in the second direction in response to the linear force brings the moveable contacts into electrical contact with the fixed contacts to close the switching mechanisms and connect the power supply to the load.

The matter for protection is set out in the appended claims.

Disclosed herein is a switching device comprising: a plurality of switching mechanisms configured to connect and disconnect a power supply from a load, the plurality of switching mechanisms arranged along a first axis and each comprising a fixed contact and a moveable contact; and an actuating mechanism for simultaneously actuating the plurality of switching mechanisms. The actuating mechanism comprises: a bridge configured to move the movable contacts of the plurality of switching mechanisms; a shaft arranged along a rotational axis parallel to the first axis, wherein the shaft is configured to rotate around the rotational axis; and one or more force transmittal mechanisms configured to convert torque from the rotation of the shaft to a linear force acting on the bridge in a second direction. The second direction is perpendicular to the first axis. Movement of the bridge in the second direction in response to the linear force brings the moveable contacts into electrical contact with the fixed contacts to close the switching mechanisms and connect the power supply to the load.

In some implementations, for each switching mechanism, the moving contact is arranged between the shaft and the fixed contact along the second direction. Optionally, the one or more force transmittal mechanisms are arranged between the shaft and the fixed contact along the second direction. Optionally, the one or more force transmittal mechanisms are coupled to the shaft.

In some implementations, each switching mechanism comprises a vacuum interrupter. Optionally, the switching device is a vacuum circuit breaker.

In some examples, the one or more force transmittal mechanisms comprise: a secondary shaft configured to rotate around a third axis perpendicular to both the first axis and the second direction; a four-bar linkage configured to apply the linear force to move the bridge in the second direction in response to rotation of the secondary shaft; and a coupling configured to rotate the secondary shaft in response to rotation of the shaft so as to transfer the torque from the rotation of the shaft to drive the four-bar linkage.

Optionally, the coupling comprises a bevel gear pair. Optionally, the bevel gear pair is a <NUM>:<NUM> bevel gear pair. In some examples, the coupling further comprises a spur gear pair, wherein the bevel gear pair and the spur gear pair are rotationally connected by a shaft extending parallel to the third axis. Optionally, the spur gear pair is a <NUM>:<NUM> spur gear pair. This arrangement can facilitate provision of a more compact device.

In some examples, the shaft and the secondary shaft overlap but are offset along the second direction. Optionally, wherein the shaft comprises an offset portion which extends parallel to the rotational axis of the shaft but is offset from the rotational axis. Optionally, the device further comprises a resiliently deformable member coupled to the offset portion of the shaft, wherein rotation of the shaft around the rotational axis in response to user input causes deformation of the resiliently deformable member, and wherein a restoring force due to deformation of the deformed resiliently deformable member causes further rotation of the shaft around the rotational axis independent of the user input. Optionally, the resiliently deformable member is a tension spring.

This offset and resiliently deformable member can facilitate provision of a toggle point, allowing user independent actuation of the device beyond the toggle point. Quicker actuating of the device may therefore be facilitated.

Optionally, the one or more force transmittal mechanisms comprise one or more cams arranged on the shaft and one or more corresponding cam followers arranged on the bridge. The cam and cam follower arrangement can facilitate reliable actuation of the switching mechanism via the shaft of the actuating mechanism whilst allowing the overall actuating mechanism to be more compact by aligning the shaft with the rest of the actuating mechanism and the switching mechanisms.

In some examples the device further comprises a latch configured to retain the actuating mechanism when the switching mechanism is closed, wherein the latch is engageable by a user to release the actuating mechanism and open the switching mechanism. The latch can engage to retain the actuating mechanism and prevent further rotation of the shaft, thereby keeping the switching mechanism closed until released by a user. Accidental opening of the device may therefore be prevented.

Also disclosed herein is a switchgear, comprising a plurality of switching devices as discussed above, wherein each switching device comprises a plurality of poles, and wherein each pole is associated with a respective switching mechanism of the switching device.

In some examples, one or more earthing or disconnection switches can also be provided. For example, the switching device described herein can further comprise a plurality of disconnector and earthing switches, each disconnector and earthing switch associated with a respective switching mechanism. Each disconnector and earthing switch can comprise a disconnector blade having a first end and a second end, wherein the disconnector blade is configured to pivot around the first end between three different positions, the three positions comprising: a first position in which the disconnector and earthing switch is closed and the power supply is connected to the load through the disconnector blade; a second, isolation, position in which the disconnector and earthing switch is open and the power supply is disconnected from the load; and a third position in which the power supply is disconnected from the load and a second end of the disconnector blade is electrically connected to an earthing contact. Such a disconnector and earthing switch (also termed an earthing disconnection switch) can be termed a 3PS switch (three position disconnector and earthing switch).

It is desirable to provide a reliable and compact switchgear with a small footprint. It is also desirable to provide an earthing disconnection switch (also termed a disconnector and earthing switch) with three positions - on, off (or isolation), and earth - to facilitate in-situ testing of cable integrity and improve the ease of maintenance of the switchgear. It is particularly desirable to combine a three-position disconnector and earthing with a compact switchgear. Such a compact switchgear can be facilitated by the switching device comprising an actuating mechanism described herein.

The following description is with reference to the Figures.

With reference to the schematic of <FIG>, an existing switchgear architecture is shown in plan (top down) view. This example switchgear 100a is a <NUM>-way, <NUM>-phase (or <NUM>-pole) device, i.e., has three switching devices <NUM>, each having three phases/poles <NUM>. In some examples, each switching device has a two-position disconnection switch for the live and earth contacts, e.g. a switch having two positions (on, earth). The disconnection switch, or disconnector and earthing switch, is not shown.

Each switching device is arranged in a panel or housing <NUM> along a longitudinal direction <NUM> (or longitudinal axis <NUM>), with the phases/poles (L1, L2, L3) for each switching device similarly arranged along the longitudinal direction. This arrangement is termed herein a "longitudinal" or "width wise" orientation. In one specific example of an existing switchgear, such a longitudinal/width wise architecture provides a width w (along the longitudinal direction <NUM>) of <NUM>, with a depth d (along a transverse direction <NUM> perpendicular to the longitudinal direction) of <NUM>. However, it will be understood that switchgears may have other dimensions and may include any suitable combination of switch types.

With reference to the schematic of <FIG>, a new switchgear architecture in accordance with the present invention is shown in plan (top down) view. This example switchgear 100b is a <NUM>-way, <NUM>-phase (or <NUM>-pole) device, i.e., has three switching devices <NUM>, each having three phases/poles <NUM>. In some examples, each switching device has a three-position earthing disconnection switch (or disconnector and earthing switch) having three positions (on, off or isolation, earth). In other examples, each switching device has a two-position disconnection switch, as per switchgear 100a. The disconnection switch, or disconnector and earthing switch, is not shown.

Each switching device <NUM> is arranged in a panel or housing <NUM> along a longitudinal direction <NUM>, but the phases/poles <NUM> for each switching device <NUM> are arranged along the transverse direction <NUM> (the poles for each switch are arranged along a respective transverse axis <NUM>). This arrangement is termed herein a "transverse" or "depth wise" orientation. In one specific example of the proposed switchgear, such a transverse/depth wise architecture provides a width w (along the longitudinal direction <NUM>) of <NUM>, with a depth d (along a transverse direction <NUM> perpendicular to the longitudinal direction <NUM>) of <NUM>. In another specific example, such a transverse/depth wise architecture provides a width w (along the longitudinal direction <NUM>) of <NUM>, with a depth d (along the transverse direction <NUM> perpendicular to the longitudinal direction <NUM>) of <NUM>. However, it will be understood that switchgears with this orientation may have other dimensions and may include any suitable combination of switch types. For example, any switchgear 100b may be provided with a plurality of switching devices <NUM>, each switching device having a plurality of poles <NUM>, arranged in accordance with the architecture of <FIG>.

In other words, the switchgear arrangement of <FIG> can be generally implemented for any switchgear comprising a plurality of switching devices <NUM> configured to disconnect a power supply from a load. By way of the novel switchgear architecture illustrated in <FIG>, the width of the switchgear product may be reduced, providing for a more compact switchgear whilst still allowing for e.g., provision of a three-position disconnection switch for the earthing contacts (three-position disconnector and earthing switch). However, there is a need to modify the actuating mechanism of the existing switchgear 100a to accommodate the depth wise orientation of the switchgear 100b. This will be described with reference to <FIG>.

With reference to <FIG>, a switching device <NUM> is described. <FIG> shows a plan view (from the top), and <FIG> shows a side view. In some particular examples, switching device <NUM> can be implemented as a vacuum circuit breaker, VCB. However, it will be understood that the switching device may be any other type of device, as required. For example, the device may be a load break switch.

Switching device <NUM> can optionally be enclosed within a housing <NUM>. One or more switching devices <NUM> can be provided in combination to provide a switchgear 100b or other disconnection device of the desired size or capacity. The one or more switching devices <NUM> can be provided within a switching compartment of the housing <NUM> (illustrated by the dashed lines).

Switching device <NUM> comprises a plurality of switching mechanisms <NUM> configured to connect and disconnect a power supply from a load. Here there are three switching mechanisms (210a, 210b, 210c), but there may be two switching mechanisms or more than three, depending on the application of the switching device <NUM>. In other words, any suitable number of switching mechanisms (of any suitable type, e.g., mechanical, electromechanical and/or solid state) may be used. The plurality of switching mechanisms are arranged along a first axis <NUM> (having the same orientation as the transverse axis of <FIG>). In other words, the switching mechanisms are placed in a depth wise orientation. Each switching mechanism <NUM> comprises a fixed contact <NUM> and a moveable contact <NUM>.

An actuating mechanism is provided for simultaneously actuating the plurality of switching mechanisms. The actuating mechanism comprises a bridge <NUM> configured to move the movable contacts of the plurality of switching mechanism. The actuating mechanism comprises a shaft <NUM> arranged along a rotational axis <NUM>. The rotational axis <NUM> is parallel to the first axis <NUM>. The shaft is configured to rotate around the rotational axis <NUM>. The shaft can be rotated or turned by way of handle <NUM>, or through any suitable mechanism.

The actuating mechanism also comprises one or more force transmittal mechanisms configured to convert torque from the rotation of the shaft to a linear force acting on the bridge <NUM> in a second direction <NUM>. The second direction is perpendicular to the first axis <NUM>. Here, the second direction is shown as being parallel to axis <NUM>. Movement of the bridge in the second direction <NUM> in response to the linear force brings the moveable contacts <NUM> into electrical contact with the fixed contacts <NUM> to close the switching mechanisms <NUM> and connect the power supply to the load. The bridge <NUM> can carry the moveable contacts <NUM> or can be otherwise configured to drive the moveable contacts into electrical contact the fixed contacts to close the switching device <NUM> (on position). The bridge <NUM> can also move the moveable contacts out of electrical contact with the fixed contacts to open the switching device (off position).

In this way, the actuating mechanism is arranged in a depth wise orientation, such that the alignment of the shaft is parallel to the alignment of the switching mechanisms <NUM> along the first axis <NUM>. In this way, a more compact design can be provided which has a smaller dimension in the width wise or longitudinal direction (along axis <NUM>). In other words, the depth wise alignment or orientation of the actuating mechanism can facilitate provision of a more compact switching device.

In some examples, a switchgear 100b is provided having the actuating mechanism described with reference to <FIG>. The switchgear comprises a plurality of switching devices according to any preceding claim. Each switching device comprises a plurality of poles, and each pole is associated with a respective switching mechanism <NUM> of the switching device <NUM>. In other words, each switching device <NUM> comprises a plurality of poles, each pole associated with a respective switching mechanism <NUM> having a fixed contact and a moveable contact, and an actuating mechanism comprising a shaft <NUM>. The shaft <NUM> is configured to rotate around a rotational axis to transfer an external input force provided via handle <NUM> to move the moveable contact <NUM> and open or close the switching mechanisms <NUM> of the respective switching device <NUM>. The plurality of switching devices are arranged along a longitudinal axis (<NUM>) within the switchgear 100b. The plurality of poles of each switching device are arranged along the first axis (<NUM>) perpendicular to the longitudinal axis. Each shaft <NUM> is arranged along a rotational axis parallel to the first axis <NUM>. A compact switchgear can therefore be provided by way of the depth wise actuating mechanism described herein.

With further reference to <FIG>, in some examples each switching mechanism can be arranged or orientated such that the moving contact <NUM> is arranged between the shaft <NUM> and the fixed contact <NUM> along the second direction. In other words, the fixed contact <NUM> is offset from the shaft along the axis <NUM>, and the moving contact is disposed between the fixed contact and the shaft. In some examples, the one or more force transmittal mechanisms are arranged between the shaft and the fixed contact along the second direction. In other words, the moving parts of the actuating mechanism are arranged between the fixed contact and the shaft, each of which are fixed in space along the axis <NUM>.

By providing a vertical offset (offset along the second direction <NUM>), the width of the switching device <NUM> (in the longitudinal direction <NUM>) may be reduced. In other words, the arrangement or orientation of the actuating mechanism and switching mechanism along the axis <NUM> or second direction can facilitate provision of a more compact switching device.

The switching mechanism can be implemented in any suitable manner or be of any suitable type, e.g., any suitable type of mechanical or electromechanical mechanism. The top contact of the switching mechanism is the moveable contact <NUM>, moveable by the actuating mechanism is response to rotation of the shaft <NUM>. The fixed contact of the switching mechanisms can be fixed to the housing <NUM>, or can be fixed in any other suitable way.

In some particular examples, each switching mechanism <NUM> is implemented as, or comprises, a vacuum interrupter (or VI). In these examples, the bridge <NUM> is configured to drive the moving contact into electrical contact with the fixed contacts. For example, the bridge can be coupled to one or more drive pins or drive rods associated with the vacuum interrupter (such as drive rods <NUM> illustrated in <FIG>) such that movement of the bridge in the second direction <NUM> actuates the vacuum interrupter. The VI can be implemented as part of a VCB, or vacuum circuit breaker. In a VCB the operation of switching on and closing of current carrying contacts (e.g. the moving or moveable contact) and interrelated arc interruption takes place in a vacuum chamber in the breaker which is called a vacuum interrupter.

The top contact of the vacuum interrupter VI is the moveable contact <NUM>, moveable by the actuating mechanism is response to rotation of the shaft <NUM>. The fixed contact of the vacuum interrupter VI can be fixed to a bottom plate of the housing <NUM> via a support plate (not shown). A housing of the VI covers the fixed and moving contacts and is bolted to the support plate. Column supports formed of an insulating material (not shown) can be bolted between the support plate and the bottom plate to hold the support plate within the switching compartment of the housing <NUM>. As discussed above, the moving contact moves within the VI housing in response to actuation/rotation of the shaft <NUM>. In particular, rotation of the shaft <NUM> actuates the drive pin/rod coupled to the bridge <NUM> of the actuating mechanism, pushing the moveable contact in the second direction <NUM> away from the shaft <NUM> and opening the switching mechanism <NUM>.

With particular reference to <FIG>, a first example implementation of the one or more force transmittal mechanisms configured to convert torque from the rotation of the shaft to a linear force acting on the bridge <NUM> in a second direction <NUM> (as discussed with reference to <FIG>) is now described. The bridge can be sandwiched between or otherwise at least partially enclosed within one or more plates <NUM>.

In this example, the one or more force transmittal mechanisms comprise a four-bar linkage <NUM> configured to apply the linear force to move the bridge in the second direction <NUM>. When the shaft <NUM> rotates, it forces the four-bar linkage <NUM> to move or pivot towards a left hand side of <FIG>: bars of the linkage consequently move from being at an angle (as shown in <FIG>) with respect to the horizontal to being perpendicular or almost perpendicular from the horizontal (as shown in <FIG>), thereby increasing the vertical component of the bar length. This increase in bar length in the vertical (i.e., along axis <NUM>) forces the bridge <NUM> to move downwards (in the second direction <NUM>). The amount of displacement, d, corresponds to the change in length of the vertical components of the bar length between the positions of <FIG>. The movement of the four-bar linkage can be further facilitated by a resiliently deformable member <NUM> and cam <NUM>, as will be understood by the skilled person, or by any other suitable components. The resiliently deformable member <NUM> is optionally an extension spring.

Such a linkage <NUM> can be the same as, or similar to, actuating mechanisms of existing switchgears 100a. In particular, the four-bar linkage is configured to apply the linear force to move the bridge in the second direction <NUM> in response to rotation of a shaft. In existing devices illustrated in <FIG>, the linkage can be directly driven by shaft <NUM> through rotation of handle <NUM>. However, the change from a width wise orientation of the switching mechanisms <NUM> to a depth wise orientation (as in <FIG>) requires modification of existing actuating mechanisms.

In the implementation of <FIG>, the one or more force transmittal mechanisms comprise a secondary shaft <NUM> configured to rotate around a third axis perpendicular to both the first axis <NUM> and the second direction <NUM> (along axis <NUM>). In other words, secondary shaft <NUM> is configured to rotate around the third axis <NUM> (aligned with the longitudinal direction <NUM> of <FIG>). The four-bar linkage <NUM> is configured to apply the linear force to move the bridge in the second direction in response to rotation of the secondary shaft <NUM>. A coupling is configured to rotate the secondary shaft <NUM> in response to rotation of the shaft <NUM> so as to transfer the torque from the rotation of the shaft to drive the four-bar linkage <NUM>.

<FIG> show perspective and side on views, respectively, of an example of the switching device <NUM> showing the linkage <NUM>, and <FIG> shows a schematic of an example of the coupling. By providing a coupling in this way, a compact switching device <NUM> can be provided with only a small modification of existing actuating mechanisms. Consequently, the user interface (e.g., the handle <NUM> or other mechanism) and mode of operation can remain the same, reducing or eliminating the need for user/operator training.

With reference to <FIG>, the coupling of this particular implementation comprises a bevel gear pair <NUM>. The bevel gear pair transfers the torque from rotation of the shaft <NUM> from the rotational axis (transverse direction) to the third axis <NUM> (longitudinal direction). This facilitates the change in orientation of the switching mechanisms relative to the actuating mechanism, i.e., allows the actuating mechanism to be aligned with the switching mechanisms. In some examples, the bevel gear pair is a <NUM>:<NUM> bevel gear pair, but any suitable gearing may be used. Bevel gears are most often used to transmit power at <NUM> degrees, or at a right angle. The axes of the two bevel gear shafts intersect and the tooth-bearing faces of the gears themselves are conically shaped. Bevel gears are most often mounted on shafts that are <NUM> degrees apart (here shafts <NUM>, <NUM>). However, any other suitable arrangement to transfer torque from one axis to another, perpendicular axis may be used instead of the bevel gear mechanism. For example, a spiral gear or worm gear may be used.

The coupling further comprises a spur gear pair <NUM>, wherein the bevel gear pair <NUM> and the spur gear pair <NUM> are rotationally connected by a shaft <NUM> extending parallel to the third axis <NUM>. In some examples the spur gear pair is a <NUM>:<NUM> spur gear pair, but any suitable gearing may be used. Any other suitable arrangement to offset torque along the axis <NUM> may be used instead of the spur gear mechanism. The use of the spur gears (or other mechanism) transfers the torque in a vertical direction (i.e., along the axis <NUM>). By offsetting the shaft <NUM> and the shaft <NUM> in the vertical direction, the shafts <NUM>, <NUM> can be placed under each other. This can facilitate provision of a more compact device. In other words, by arranging the shaft <NUM> and the secondary shaft <NUM> to overlap, but then offsetting the shafts in the second direction <NUM> (so that when viewed in a plan view they appear to intersect, but do not actually touch), a smaller and more compact switching device <NUM> can be provided.

In some implementations, the switching device further comprises a latch <NUM> configured to retain the actuating mechanism in a fixed position when the switching mechanism is closed. For example, as the actuating mechanism pushes the bridge in the second direction <NUM> and closes the switching mechanism <NUM>, the latch <NUM> can engage to retain the actuating mechanism. In some examples, such as is illustrated with reference to <FIG>, a latching portion 348a of the latch <NUM> is coupled to or otherwise arranged on shaft <NUM>. An engagement portion 348b of the latch is configured to engage the latching portion to retain the actuating mechanism (i.e., to prevent the bridge from moving in a direction opposite the second direction <NUM>) by preventing further rotation of the shaft <NUM>. The engagement portion may be coupled to the housing <NUM> or may be arranged and/or fixed in any suitable manner to retain the actuating mechanism.

The latch <NUM> is further engageable by a user to release the actuating mechanism and open the switching mechanism. In other words, a user can press, depress or otherwise move the latch to allow the bridge to move in a direction opposite the second direction, thereby allowing the switching mechanism <NUM> to open. In some examples, such as is illustrated with reference to <FIG>, the engagement portion 348b of the latch is engageable by the user to release the actuating mechanism and open the switching mechanism. For example, the engagement portion may comprise a trigger or be otherwise moveable to allow the latching portion 348a to be released or disengaged. Release or disengagement of the latching portion can allow the shaft <NUM> to rotate around the rotational axis, thereby allowing for opening of the switching mechanism.

In the particular example of <FIG>, the latch <NUM> retains the four-bar linkage in the leftward position, where the bars of the linkage are perpendicular or almost perpendicular from the horizontal, thereby increasing the vertical component of the bar length. As discussed above, this increase in bar length in the vertical (i.e., along axis <NUM>) forces the bridge <NUM> to move downwards (in the second direction <NUM>). By retaining the four-bar linkage <NUM> in this position, the bridge is also retained in this downward position with the switching mechanism <NUM> closed. Engagement of the latch <NUM> by a user allows the four-bar linkage to pivot back towards the right of <FIG>, angling the bars with respect to the horizontal and shortening the vertical length component along axis <NUM> (thereby allowing the bridge <NUM> to move upwards and opening the switching mechanism).

The bevel and spur gear pairing illustrated in <FIG> can facilitate reliable actuation of the switching mechanism <NUM> via the shaft <NUM> of the actuating mechanism whilst allowing the overall actuating mechanism to be more compact by aligning the shaft <NUM> with the rest of the actuating mechanism and the switching mechanisms. A smaller footprint can therefore be achieved. These benefits are further increased when the switching device <NUM> is implemented as part of a switchgear 100b, where a more compact switchgear can be provided. Moreover, as a result of the smaller footprint, the manufacturing costs of the overall switchgear may be reduced (fewer materials, smaller housing), facilitating provision of a robust and cost effect switchgear. Additionally, it may not be necessary to provide extra user/operator training as the user interface (i.e., the handle <NUM>) of is kept same as existing switchgear 110a products.

With particular reference to <FIG>, a second example implementation of the one or more force transmittal mechanisms configured to convert torque from the rotation of the shaft to a linear force acting on the bridge <NUM> in a second direction <NUM> (as discussed with reference to <FIG>) is now described.

In the implementation of <FIG>, which show a perspective view of an example of the switching device <NUM> showing the force transmittal mechanism, the one or more force transmittal mechanisms comprise one or more cams <NUM> arranged on the shaft <NUM> and one or more corresponding cam followers <NUM> arranged on the bridge <NUM>. As the shaft <NUM> rotates around the rotational axis, the cams <NUM> rotate with the shaft. The cams <NUM> are shaped to exert a force on the cam followers <NUM> as the shaft <NUM> rotates, which in turn forces the bridge <NUM> to move downwards (in the second direction <NUM>).

Although not shown here, a latch may be provided as discussed above with respect to <FIG>. For example, as the cam <NUM> and cam follower <NUM> pushes the bridge in the second direction <NUM> and closes the switching mechanism <NUM>, a latch can engage to retain the actuating mechanism and prevent further rotation of the shaft <NUM>. Engagement of the latch by a user allows the shaft <NUM> to continue to rotate, in turn rotating the cams <NUM> which are shaped to (after closing of the switching mechanism) allow the bridge <NUM> to move upwards again. The cams <NUM> may be shaped to facilitate rapid movement of the bridge, and thus rapid opening of the switching mechanism, facilitating quick breaking of the circuit through the switching device <NUM>.

With further reference to <FIG> shows a perspective view of an example of the switching device <NUM> of <FIG>, and <FIG> shows a schematic illustration of the force transmittal mechanism of this example.

In this example, the shaft <NUM> comprises an offset portion 214a which extends parallel to the rotational axis <NUM> of the shaft <NUM> but is offset from the rotational axis <NUM>. The offset portion <NUM> can be joined or coupled to the rest of the shaft <NUM> (i.e., the main portion of the shaft which is actuated by a user through handle <NUM>) by way of an S bend. In other examples, the offset portion 214a is formed from the shaft <NUM> by introducing or creating an S bend.

The switching device <NUM> further comprises a resiliently deformable member <NUM> coupled to the offset portion 214a of the shaft <NUM>. Rotation of the shaft <NUM> around the rotational axis <NUM> in response to user input causes deformation of the resiliently deformable member <NUM>. The resiliently deformably member <NUM> may be coupled to the housing <NUM> at the other end, or may be arranged and/or fixed in any suitable manner to facilitate deformation of the member <NUM> as the shaft <NUM> rotates. In this example, the resiliently deformable member is configured to hinge or rotate around a hinge point <NUM> (arranged at the end of the member <NUM> which is opposite coupled to the offset potion 214a), but any other suitable fixing or coupling point <NUM> may be used.

In this example, the resiliently deformable member is a tension spring. In other words, due to the offset portion 214a being offset from the rotational axis <NUM>, the resiliently deformable member is pulled or extended in the second direction <NUM>. A maximum extension is experienced by the member <NUM> when the shaft <NUM> is rotated <NUM> degrees from the position shown in <FIG> (i.e., where the rotational axis <NUM> extends between the coupling point <NUM> of the member <NUM> and the offset portion 214a. A restoring force due to deformation (i.e., extension) of the deformed resiliently deformable member <NUM> causes further rotation of the shaft <NUM> around the rotational axis. This further rotation of the shaft can be independent of the user input. In other words, the offset portion 214a and resiliently deformably member <NUM> act to provide a toggle point for the actuating mechanism, after which toggle point the closing of the switching mechanism is user independent. This mechanism is discussed in more detail with reference to <FIG>.

It will be understood that in other examples the member <NUM> may be any other suitable component. For example, a compression spring may be used, wherein the resiliently deformable member is configured such that maximum compression occurs at the position shown in <FIG>; the restoring force then acts to push the offset portion 214a away from the resiliently deformable member <NUM>, driving the shaft <NUM> independent of user input. However, any other resiliently deformable member (which is resiliently deformable through form and/or function) may be used.

With reference to <FIG>, three distinct positions of the shaft <NUM> are shown, corresponding to different angles of rotation of the shaft <NUM> around the rotational axis <NUM>. As discussed above, a user can provide an input motion to the actuating mechanism through the shaft <NUM>. The operator uses handle <NUM> (or other input means) to rotate the shaft <NUM> around the rotational axis <NUM> (from <NUM> degrees to <NUM> degrees). Position <NUM> is an illustrative position within this range, where the cam is illustratively orientated at <NUM> degrees below the horizontal. In this example, the shaft (and cam) are being rotated around the rotational axis in a clockwise direction.

At or just after <NUM> degrees (as shown in position <NUM>) the resiliently deformable member <NUM> (here an extension spring) is at maximum deformation. This is the toggle point - before <NUM> degrees of rotation, the restoring force from the extension spring <NUM> would cause the shaft <NUM> to rotate in the opposition direction (i.e., in the direction opposite to the direction of user rotation). After <NUM> degrees, the user can release the handle and the resultant restoring force causes the shaft <NUM> to continue to rotate in the same direction of rotation. In other words, the restoring force of the deformed (extended) spring <NUM> rotates the shaft (and cam) in the clockwise direction. The cam is now illustratively orientated at <NUM> degrees.

At position <NUM>, the cam <NUM> - cam follower <NUM> pair act to convert the torque from rotation of the main shaft into movement along axis <NUM>. In particular, the cam <NUM> is shaped to cause displacement or vertical motion of the bridge <NUM> in the second direction <NUM>. In this example, the vertical displacement of the bridge <NUM> is shown by the distance d. This displacement d is sufficient to cause the switching mechanism to close. In this position, the resiliently deformable member can be undeformed, and there is no restoring force being applied to cause rotation of the shaft <NUM>.

Where a latch is provided, the shaft <NUM> can be latched in this position to prevent further rotation of the shaft <NUM> (and thus to prevent accidental or unintended opening of the switching mechanism). Additionally or alternatively, the cam and/or cam follower may be shaped to prevent further rotation of the shaft independent of user input. For example, one or more recesses, detents or protrusions may be used to engage the cam and the cam follower, thereby requiring a threshold input torque to be applied through the shaft <NUM> to open the switching mechanism <NUM>.

Claim 1:
A switching device (<NUM>) comprising:
a plurality of switching mechanisms (<NUM>) configured to connect and disconnect a power supply from a load, the plurality of switching mechanisms arranged along a first axis (<NUM>) defining a first direction and each comprising a fixed contact (<NUM>) and a moveable contact (<NUM>); and
an actuating mechanism for simultaneously actuating the plurality of switching mechanisms, the actuating mechanism comprising:
a bridge (<NUM>) configured to move the movable contacts of the plurality of switching mechanisms;
a shaft (<NUM>) arranged along a rotational axis parallel to the first axis,
wherein the shaft is configured to rotate around the rotational axis; and
one or more force transmittal mechanisms configured to convert torque from the rotation of the shaft to a linear force acting on the bridge in a second direction (<NUM>),
wherein the second direction is perpendicular to the first axis and wherein movement of the bridge in the second direction in response to the linear force brings the moveable contacts into electrical contact with the fixed contacts to close the switching mechanisms and connect the power supply to the load.