Patent Description:
A switch-disconnector, disconnect switch or isolator switch is used to break a current conduction path to ensure that an electrical circuit is de-energized and safe for service or maintenance. Such switch-disconnectors or switches are often found in electrical distribution and industrial applications. Switch-disconnectors can be operated either manually or automatically.

Manual switch disconnectors can be either independent (of a user input, i.e. the switch is simply switched on or off) or dependent, where the speed of the switching operation is controlled by user input (i.e. the speed of actuation by the user), or a combination of the two. For example, a manual dependent operation can control the make of the switch, whilst an independent operation (initiated by a user and then independent of user input) can be used to break the switch (or vice versa). This operation can be termed semi-independent.

There is a need for a simpler switch disconnector with semi-independent operation, which has a reduced manufacturing/assembly cost and complexity as compared to other known disconnectors.

<CIT> discloses a movable switching bar in a housing with at least one contact bridge corresponding to the number of phases for making electrical connections between input and output contact arrangements on opposite dies of the switching bar. The switching bar is vertically movable by a cam element and can be latched in different switch positions by a spring-loaded cam system.

<CIT> discloses a rotary-controlled multipole electric switch fitted with a handle and a housing in which a cam device transforms the rotation of the handle into a translational movement of contact bridges. In order to ensure coordination between a cylindrical control core and a slider <NUM> bearing contact bridges, the cam device is fitted with at least two notches offset around the axis of rotation X of the knob, and with a control projection applied respectively to the bottom of one notch in the OFF position and to the bottom of the other notch in the ON position by the force supplied by springs acting on the slider and contact pressure springs.

According to the invention, a switch-disconnector is provided as defined in the first appended independent apparatus claim, with optional features defined in the dependent claims appended thereto. Features can be combined in any suitable combination. The term "switch-disconnector" is used herein, but it will be understood that the principles described herein can apply equally to other disconnectors or disconnector devices such as circuit breakers, load disconnectors or any other form of electrical disconnection or isolation device.

Described herein is a disconnector, or switch disconnector, as set forth in claim <NUM>.

In some examples, the biasing member is resiliently deformable. The device may therefore work in either tension or compression, allowing for semi-independent make or break operation. Optionally, the biasing member comprises a spring which is configured to compress as the moveable bridge contact is urged in the axial direction. The disconnector may therefore be cheaper and easier to assemble.

The biasing member comprises two or more springs (optionally three springs) arranged equidistant along a length of the moveable bridge contact, each configured to compress as the moveable bridge contact is urged in the axial direction. This arrangement can improve stability and reliability of a semi-independent make or break operation (i.e. an operation at least partially independent of user input) by improving control of the user independent motion of the bridge contact <NUM>. For example, the bridge contact may wobble less.

Optionally, where there are three or more springs, one or more middle springs can be initially configured to compress as the cam follower is urged in the axial direction. This can help prevent accidental operation of the device, and provide robustness against accidental input since the bridge contact is only moved after a predetermined amount of rotational input is applied.

In one example, the first and second fixed contacts are arranged between the cam follower and the moveable bridge contact, such that: in the first position the moveable bridge contact is in electrical contact with the first and second fixed contact terminals to define a current conduction path between the first conductor and the second conductor, and in the second position the moveable bridge contact is electrically and physically separate from the first and second fixed contact terminals and the current conduction path is open. A controlled break operation and an at least partially independent make operation can therefore be provided. This can allow the switch make to be achieved quickly, which can be of benefit in applications were rapid electrical connection is required.

In another example, the moveable bridge contact is arranged between the cam follower and the first and second fixed contacts, such that: in the second position the moveable bridge contact is in electrical contact with the first and second fixed contact terminals to define a current conduction path between the first conductor and the second conductor, and in the first position the moveable bridge contact is electrically and physically separate from the first and second fixed contact terminals and the current conduction path is open. A controlled make operation and an at least partially independent break operation can therefore be provided. This can allow the switch break to be achieved quickly, which can be of benefit in applications were rapid electrical disconnection is required.

Optionally, the cam surface comprises a protruding portion and the following surface comprises a detent or recess, the protruding portion configured to be received by the detent; this alignment of the protruding portion and recess can define a stop position of the urging member, wherein when the urging member is in the stop position the moveable bridge contact is in the second position. In this way, user input can be required to operate the subsequent make/ break of the switch, since the protruding portion needs to be released from the stop. Accidental operation may therefore be prevented.

Optionally, the urging member is fixed in the axial direction; this can improve the efficiency of the urging of the cam follower, and facilitate a smaller disconnector device. Optionally, both the following surface and the cam surface comprise corresponding angled portions which are in contact with one another when the moveable bridge contact is in the first position. This can facilitate a smaller disconnector device, since the cam portions of the urging member and cam follower can be at least partly nested.

Optionally the angled portion is angled such that the urging of the moveable bridge contact in the axial direction from the first position to the second position is dependent on user input, and movement of the moveable bridge contact towards the first position by the biasing mechanism is at least partially independent of user input.

Optionally the disconnector further comprises a housing configured to enclose the switch and the actuating mechanism. Optionally the housing comprises two portions, a front/top portion and a rear/bottom portion. The manufacturing and construction of the switch disconnector may therefore be quicker and cheaper. Optionally, the front portion may be at least substantially flat. A smaller disconnector may therefore be provided, and fewer materials may be needed for manufacturing the disconnector. The disconnector described herein may therefore be cheaper and require fewer resources to manufacture than other disconnectors.

Optionally, the disconnector further comprises a second switch, wherein the cam follower is also configured to move the moveable bridge contact of the second switch in response to the urging, and wherein the actuating mechanism comprises a second biasing member configured to act on the moveable bridge member of the second switch. Higher rated devices may therefore be isolated with the disconnector.

Optionally, the switch and the second switch are arranged along a direction perpendicular to the axial direction. This arrangement can be particularly space efficient, and can allow for a smaller and more compact device to be provided.

In accordance with the invention, a method of operating a disconnector as set forth in claim <NUM> is provided.

Disclosed is an electrical apparatus comprising any example of the disconnector described herein.

The following description is with reference to the following Figures:.

With reference to <FIG> (<FIG> and <FIG>), a switch disconnector <NUM> for opening a current conduction path is described. Switch-disconnector <NUM> is described herein as a switch-disconnector to isolate an electrical component (which can be after a current has been interrupted by another control device if the switch-disconnector has a low load capability), although it will be understood that the principles described herein could be applied to a load or switch switch-disconnector or circuit breaker or any other form of electrical disconnection device.

Switch disconnector <NUM> comprises a switch <NUM>, the switch <NUM> comprising a first contact terminal <NUM> of a first conductor, a second contact terminal <NUM> of a second conductor, and bridge contact <NUM>. These components are separate, conducting, components of the switch, arranged to define a current conduction path (when the contact terminals <NUM>, <NUM> are electrically connected to an external circuit upon installation of the switch-disconnector <NUM>) by way of electrical contact between the first and second contact terminals <NUM>, <NUM> and the bridge contact <NUM>.

The first and second contact terminals <NUM>, <NUM> are fixed, rigid, components of the switch <NUM>, and the bridge contact <NUM> is a moveable switching component. For example, in a first position of the bridge contact <NUM>, the bridge contact and first and second contact terminals <NUM>, <NUM> are in electrical contact and define the current conduction path. In this position, the switch is closed and current can flow through the switch <NUM>. In this example, movement of the bridge contact <NUM> in a direction <NUM> towards a second position, in which the bridge contact and first and second contact terminals <NUM>, <NUM> are electrically separate, opens the switch <NUM>. Opening the switch <NUM> breaks the current conduction path and isolates from its power source any apparatus which is connected to the electrical circuit on which the switch-disconnector is arranged. In particular, actuation of the bridge contact <NUM> in the direction <NUM> causes this electrical separation to occur by way of the physical separation of the bridge contact <NUM> from the first and second contact terminals. This operation is described in more detail below with reference to <FIG> and <FIG>.

Switch-disconnector <NUM> further comprises a housing <NUM>, enclosing at least the components of switch <NUM>. In particular, the first and second contact terminals <NUM>, <NUM> of conductors and the bridge contact <NUM> are disposed within the housing <NUM> of the switch-disconnector <NUM>. In other words, the first and second contact terminals <NUM>, <NUM> are the end portions of conductors via which the device is connected to an external circuit and are the portions which are used within the switching mechanism of a switch-disconnector, i.e. the portions which make or break the circuit. Connection of the conductors associated with the first and second contact terminals to an external circuit outside of the housing <NUM> of the switch-disconnector can be by way of any suitable electrical connection, and suitable openings in the housing <NUM> can allow for such connection.

An advantage of the disconnector arrangement described herein is that the housing <NUM> can be constructed in two halves; for example, the switch and actuating mechanism can be built into a lower half or base 126b of the housing (or a back half, depending on the orientation of the switch), and then a front portion 126a may be provided afterwards. In other words, housing <NUM> comprises two housing portions, a front/top portion 126a and a rear/bottom portion 126b. The manufacturing and construction of the switch disconnector may therefore be quicker and cheaper.

Another advantage of the disconnector arrangement described herein is that the front portion 126a of the housing may be flat (with the exception of additionally mounted rotary component, or knob, <NUM>). In particular, since the arrangement of the actuating mechanism and switch obviates the need for the additional mechanisms used in existing disconnector devices to assist the operation of the urging member cam, the depth of the disconnector <NUM> (here, the thickness along direction <NUM>) can be significantly reduced. A smaller disconnector may therefore be provided, and fewer materials may be needed for manufacturing the disconnector. The disconnector described herein may therefore be cheaper and require fewer resources to manufacture than other disconnectors.

With further reference to <FIG>), actuation of the bridge contact <NUM> is controlled by an actuating mechanism <NUM> of the switch-disconnector <NUM>. In one example, a rotational movement <NUM> of rotary component <NUM> (here shown as a manually operated knob, but any other suitable component may be used) of the actuating mechanism <NUM> causes actuation of the bridge contact <NUM> in direction <NUM> (i.e. from the first position to the second position). In particular, the linear actuation of the bridge contact <NUM> in direction <NUM> is controlled by manual user input of the rotary component <NUM>, and the movement of the bridge contact <NUM> back to the first position is independent of user input, as will be described below in more detail.

The actuating mechanism <NUM> comprises an urging member <NUM> rotatable in direction <NUM> around an axis extending in direction <NUM> (which rotation is in response to actuation of the rotary component <NUM> by a user). The speed of rotation of the urging number <NUM> in this direction is thus user dependent. The urging member <NUM> is configured as cam, and the actuating mechanism further comprises a cam follower <NUM> which is arranged such that movement of the cam follower causes a corresponding movement of the movable bridge contact <NUM>. Optionally, the cam follower is coupled to the moveable bridge contact; this can be advantageous when rapid switch make/break is required, since user input has an instant effect on the position of the moveable bridge contact. Optionally, a portion of the cam follower is arranged around the moveable bridge contact such that the cam follower at least temporarily contacts, but is not coupled to, the moveable bridge contact <NUM>. As described herein, the urging member <NUM> is fixed in the axial direction <NUM> and rotatable relative to the cam follower <NUM> to cause displacement of the cam follower (and thus of the bridge contact <NUM>) by interaction between the cam follower and the urging member.

The urging member <NUM> comprises a cam surface <NUM>, and the cam follower <NUM> comprises a following surface <NUM> along which the cam surface travels as the urging member rotates. The following surface <NUM> is configured to engage with the cam surface <NUM> to cause the cam follower <NUM> to move in the linear direction <NUM> in response to rotation <NUM> of the urging member <NUM> position (i.e. as the height of the cam surface <NUM> changes, the cam follower moves accordingly such that the following surface remains in contact with the cam surface), thereby moving the bridge contact <NUM> from the first position towards the second. This arrangement is contrary to other semi-independent or independent mechanisms, which comprise spring powered mechanisms which operate to move a contact carrying bridge in a transverse or lateral direction (i.e. in a direction perpendicular to the axial direction <NUM>) to open a current conduction path, and can facilitate for simpler and cheaper manufacturing, since fewer components may be required. For example, the need for mechanisms and cams to separately drive the springs can be eliminated by the proposed linear arrangement of the bridge contact and biasing member. This arrangement can also provide flexibility in the arrangement for the making/breaking of the switch, as will be discussed further with reference to <FIG>.

Moreover, the arrangement disclosed herein is contrary to other semi-independent or independent mechanisms which operate to indirectly move a contact carrying bridge in an axial direction by way of additional, cam operated, spring and/or cam powered mechanisms. For example, in some previous switch arrangements the rotation of a cam causes lateral movement (i.e. movement perpendicular to the axial direction) of a cam follower, which lateral movement can act on one or more spring mechanisms to indirectly actuate the bridge contact in a different direction. In contrast, the present, linear, arrangement allows the rotation of the urging member or cam component to directly displace the cam follower in the axial direction and therefore directly actuate or more the bridge contact, and so eliminates the need for such additional cam or spring based mechanisms. By removing the need to translate movement between different directions during operation, a smaller and simpler device may be provided.

In order to urge the moveable bridge contact <NUM> in direction <NUM>, i.e. in order to provide a force to the bridge contact <NUM> to move it in direction <NUM>, at least one of the following surface and the cam surface comprises an angled portion 118a, 120a. As the urging member <NUM> rotates in direction <NUM>, the angled portion 120a of the cam surface <NUM> can rotate along the following surface <NUM> of the cam follower <NUM> (or the cam surface <NUM> can rotate along the angled portion 118a of the following surface <NUM>); the fixed position of the urging member <NUM> in combination with the rotation of the angled portion 118a or 120a relative to the other surface causes the cam follower <NUM> to move in the axial direction <NUM>.

The at least one angled portion can be a straight angled portion, or the cam(s) can be arranged to comprise at least one helical or spiral portion. The at least one angled portion is angled with respect to the axial direction <NUM>, and may be arranged at a constant or varying angle depending on the geometry of the components. In some examples, the angled portion(s) 118a, 120a can both be angled at between <NUM> degrees and <NUM> degrees relative to direction <NUM>, optionally angled at between <NUM> and <NUM> degrees, optionally angled at <NUM> degrees or substantially at <NUM> degrees. Optionally, the angled portions can be at smaller or greater angles relative to the direction <NUM>, as appropriate. It will be understood that the angle of the angled portion with respect to direction <NUM> influences the force required to operate the switch, as well as the amount of displacement provided per degree of rotation of the rotary component <NUM>. The cam geometries, including the angle of the angled portion, may therefore be chosen for a particular application. As described herein, the cams may be designed such that each comprises an angled portion, wherein the two angled portions are arranged to correspond to one another, such that the surfaces of the cams may be in contact along the entire length of the angled portion.

The actuating mechanism <NUM> further comprises a biasing member <NUM>, configured to act on the movable bridge contact <NUM> to oppose its movement in the axial direction <NUM>. In other words, the biasing member <NUM> exerts a force on the movable bridge contact <NUM>, and/or on the cam follower <NUM> which at least temporarily contacts the bridge contact <NUM>, the force being exerted in direction <NUM> opposite to direction <NUM> when the bridge contact is actuated. The force exerted by the biasing member <NUM> is less than the force exerted by the urging member <NUM>, such that manual actuation of the rotatable component <NUM> causes an opening of the current conduction path by displacement of the movable bridge contact <NUM>, described above. However, the force exerted in direction <NUM> is sufficient to move the movable contact <NUM> back to the first position in the absence of any user input. In this way, independent closing (making) of the switch <NUM> is provided.

The biasing member <NUM> is shown here as a series of springs (see <FIG>), but the biasing member may be any other resiliently deformable member configured to exert a force in direction <NUM> in response to compression or other deformation caused by movement the bridge contact <NUM>. For example, a flexible arm or leaf spring may be used and/or a rubber or elastic members arranged under tension or compression. It will be understood that the resiliently deformable member, shown here under compression, can also be arranged under tension; for example, as the bridge contact <NUM> is displaced in direction <NUM>, the biasing member may be placed in extension, with a restoring force being exerted in direction <NUM>. For example, a spring or rubber or elastic remember may be stretched as the bridge contact <NUM> moves. It will be understood that the force exerted by the biasing member may be sufficient that the disconnector <NUM> can be placed in any orientation. For example, the disconnector may be orientated such that direction <NUM> is perpendicular to the arrangement shown in <FIG>. Utility of the switch disconnector may therefore be improved.

In the example described herein, a series of three springs, arranged equidistant along the length of the movable bridge contact <NUM>, are provided. In some examples, the cam follower <NUM> is coupled to the moveable bridge contact, such that movement of the cam follower <NUM> directly moves the moveable bridge contact <NUM>. Each spring is configured to compress as the movable bridge contact is urged in the axial direction <NUM>, and therefore to exert an opposing force in direction <NUM>. According to the invention, two springs are provided, one at each end of the bridge contact <NUM>. Alternatively, a single spring may be provided, optionally in the middle of the bridge contact <NUM>. The number and arrangement of the springs, or other biasing members <NUM>, can be determined based on the particular application. For example, more springs may improve contact between the components of the switch <NUM>, and/ or increase the reliability of the making operation (or breaking operation, as described below) by controlling the movement of the bridge contact <NUM>. However, for some applications fewer springs or a smaller biasing member may be a suitable trade-off for a lower cost, low complexity device.

As can be seen further with reference to <FIG>, in some examples described herein there are three springs, which springs can fulfil different functions at different parts of the break operation. For example, it can be seen that two of the springs (the ones at either end of the bridge contact <NUM>) are located beneath the moveable bridge contact <NUM>; these are springs 116a. Springs 116a may be in direct physical contact with the bridge contact <NUM>, or may be in indirect contact, for example via an insulating portion. The middle spring 116b is arranged beneath the middle of the bridge contact <NUM>, but is in contact with the cam follower <NUM> rather than the bridge contact <NUM> itself.

When the urging member or cam <NUM> is rotated in direction <NUM> (here, direction <NUM> is anticlockwise), spring 116b associated with the cam follower <NUM> is activated, and is compressed until a portion of cam follower <NUM> contacts the movable bridge contact <NUM> (see <FIG> for further description of the arrangement of the cam follower), wherein the cam follower <NUM> begins to urge the moveable bridge contact <NUM> with it along direction <NUM>. This movement of the bridge contact subsequently causes springs 116a to begin to compress. All three springs of the biasing member <NUM> are then providing a restoring force on the cam follower <NUM> due to the contact between the bridge contact and the cam follower in anticipation of a subsequent switch make operation.

In other words, the biasing member comprises three springs arranged equidistant along a length of the moveable bridge contact; each is configured to compress as the moveable bridge contact is urged in the axial direction, but in response to different initial inputs. A middle spring 116b of the three springs is configured to compress as the cam follower is urged in the axial direction, and the other two springs 116a (the end springs) are configured to subsequently compress only when the moveable bridge contact <NUM> moves, i.e. after a predetermined displacement of the cam follower causes a portion of the cam follower to contact the moveable bridge contact and begin urging it in the axial direction. This arrangement can facilitate a more robust switch, since small or accidental inputs do not cause breaking of the circuit through the switch (instead, switch 116b can absorb said small inputs, and only large inputs which cause sufficient displacement of the cam follower that it contacts the bridge contact act to trigger the disconnector <NUM>).

In some examples, the cam surface <NUM> can comprise a protruding portion 120b which contacts the angled portion 118a as the urging member <NUM> rotates. The following surface <NUM> comprising the angled portion 118a follows the movement of the protruding portion 120b of the cam surface. In particular, the biasing member <NUM> exerts a force on the cam follower in direction <NUM> which pushes the following surface into the cam surface; the interplay between downward force from user controlled urging member <NUM> and the upward force from the biasing member <NUM> ensures a contact between the following and cam surfaces during operation of the disconnector <NUM>. Additionally or alternatively, the following surface <NUM> can comprise a protruding 118b or flat portion which contacts angled portion 120a of the cam surface <NUM>. In some examples, both the following surface and the cam surface comprise corresponding angled portions which are in contact with one another when the movable bridge contact <NUM> is in the first position. In this way, a smaller switch may be provided, since the respective angled portions of the urging member and the cam follower can mate when the bridge contact is in the first position.

In some arrangements, the protruding portion of the cam surface is arranged to be received within a detent or recess 118c in the following surface <NUM>. When the protruding portion 120b is received by the detent 118c, a stop position of the urging member <NUM> is defined. In other words, the stop position can be considered as the position of the urging member <NUM> when the protruding portion 120b and the recess, or detent, 118c are aligned. In the arrangements described herein, the urging member rotates <NUM> degrees in direction <NUM> before reaching the stop position. However, it will be understood that depending on the cam arrangement and geometry, more or less rotation may be provided by a user before a stop position is reached. Moreover, to return the bridge contact to the first position, the rotation can be in a direction opposite direction <NUM> or the urging member <NUM> may continue to rotate in direction <NUM>, depending on the particular cam configurations used.

It will also be understood that, in some examples, rotation of the urging member <NUM> in a first direction (direction <NUM>) to the stop position may be at least partially user independent. In particular, in examples where a user rotates the urging member until the protruding portion 120b of the cam surface is aligned with protruding portion 118b of the following surface (the point of maximum compression of the biasing member, where the bridge contact is at maximum displacement from the rest of the switch), further rotation of the urging member may be user independent due to the angled portion of the following surface which extends between protruding portion 118b and recess 118c. This angled portion of the following surface causes the protruding portion 120b to follow the following surface to recess 118c and the stop position without any user input.

At the stop position, movement of the bridge contact <NUM> under the opposing force of the biasing member <NUM> is prevented. The detent prevents further rotation of the urging member <NUM>, in either direction, without manual input. Should a user wish to move the bridge contact <NUM> back to the second position, an initial input can be provided to release the protruding portion 120b from the detent 118c; the biasing member <NUM> then applies a force in direction <NUM>, causing the cam follower to move in direction <NUM>. In the present examples, the cam follower <NUM> acts to urge the urging member <NUM> to rotate in a direction opposite to direction <NUM>, which rotation is facilitated by the at least one angled portion 118a, 120a (the cam surface can slide along the following surface as the urging member rotates). In other arrangements, the detent can be provided on the cam surface (rather than the following surface), with a corresponding protruding portion 118b on the following surface. Depending on the cam geometry or arrangement, further rotation of the urging member in direction <NUM> may also/instead release the urging member from the stop position and cause the bridge contact to return to the first position under the force of the biasing member <NUM>.

In some arrangements, a protruding portion 118b is provided in combination with the detent 118c on the following surface <NUM>, along with the protruding portion 120b of the cam surface <NUM> (it will be understood that the features described with reference to the cam surface may be otherwise provided on the following surface, and vice versa). By providing such a protruding portion on the following surface, here located between the angled portion 118a and the detent 118c, the protruding portion 120b has to travel over the protruding portion 118b before reaching the stop position in detent 118c. When the two protruding portions of the cams contact, a maximum compression (or tension) of the biasing member <NUM> can be applied; the subsequent release of the biasing member <NUM> as the protruding portion the urging member travels towards the stop position at the detent or recess 118c can provide a physical feedback to the user that the stop position is reached. This can improve reliability of operation of the disconnector and so improve safety.

As illustrated in <FIG>, the switch disconnector <NUM> comprises three separate switches <NUM>, arranged along a direction <NUM> perpendicular to axial direction <NUM>. In the examples illustrated herein, each separate switch <NUM> comprises a separate biasing member <NUM> (in this arrangement, a set of three individuals springs aligned along a length of each bridge contact <NUM>). However, it will be understood that a single biasing member <NUM> may be provided for the entire series of switches <NUM>. The number and positional relationship of the switches <NUM> can be determined by the particular application for the switch disconnector <NUM>, such as the size of the switch and/or the rating capacity; in some examples, there may be only one switch <NUM>, there may be two switches <NUM>, there may be three switches, or three or more switches, et cetera.

As illustrated in <FIG>, which shows the cam follower of the arrangement <FIG>, the cam follower <NUM> comprises three sections, each of which supports a separate one of the three bridge contacts <NUM>. In this way, each switch <NUM> of the disconnector <NUM> may be operated simultaneously in response to actuation of a single urging member <NUM> by rotary component <NUM>. However, it will be understood that when multiple switches <NUM> are provided within a single housing <NUM>, each switch may be individually actuated with a separate actuating mechanism <NUM> in the manner described herein.

The first position <NUM> and the second position <NUM> of the movable bridge contact is described further with reference to <FIG> and <FIG>. As discussed above, in the first position <NUM> of the bridge contact <NUM>, the bridge contact and first and second contact terminals <NUM>, <NUM> are in electrical contact and define the current conduction path. In this position, the switch is closed and current can flow through the switch <NUM> (see e.g. <FIG>). The cam surface and the following surface of the urging member and the cam follower, respectively, each comprise an angled portion 118a, 120a. The cam (or urging member) and cam follower are arranged such that the two angled portions are aligned and the cam surface and the following surface are in contact along at least the angled portions. This minimises the depth of the switch disconnector <NUM>, facilitating provision of a smaller disconnector device.

Upon rotation of the rotary component <NUM> by a user, the urging member forces the cam follower in direction <NUM>. In other words, by rotating the rotary component in a first direction <NUM>, the urging member <NUM> is rotated around the axial direction <NUM> relative to the cam follower, optionally until a stop position is reached. Rotating the urging member urges the cam follower in the axial direction. This urging can compress (or tension, as appropriate) a portion of the biasing member (here spring 116b) which is coupled to, or arranged in contact with, the cam follower <NUM>.

The cam follower here comprises a void <NUM> in which the moveable bridge contact <NUM> is located, the void bounded along direction <NUM> by first <NUM> and second <NUM> surfaces (see also <FIG>). It will be understood that the protection against accidental rotation or input provided by the device can be in part dependent on the dimensions of the void -a greater void depth along the axial direction <NUM> (i.e. between first surface <NUM> and second surface <NUM>) means the cam follower must travel further before contacting the moveable bridge contact, so a greater degree of rotation needs to be applied by a user before the switch is activated. The protection against accidental operation may therefore be predetermined or preconfigured by changing the void dimensions.

As the cam follower is urged in the axial direction <NUM>, the first surface <NUM> contacts a surface 108a of the moveable bridge contact. The urging of the cam follower <NUM> causes surface <NUM> to push down on surface 108a, which pushing causes a temporary contact between the cam follower and the bridge contact, and a corresponding movement of the moveable bridge contact <NUM> in direction <NUM>. As the bridge contact <NUM> moves, another portion of the biasing member (here springs 116a) compresses (or tensions, as appropriate), which causes the biasing member <NUM> to oppose the urging of the moveable bridge <NUM>. Without sustained user input, the biasing member will thus force the moveable bridge <NUM> back to the first position <NUM>. For this reason, the detent is provided. In other examples the bridge contact <NUM> is coupled (optionally rigidly) to the cam follower <NUM>, and is correspondingly moved in direction <NUM> towards the second position <NUM> shown in <FIG>in response to the urging of the cam follower.

In the second position <NUM>, the bridge contact <NUM> and first and second contact terminals <NUM>, <NUM> are electrically separate, which opens the switch <NUM>. This is the switch break operation. Opening the switch <NUM> breaks the current conduction path and isolates from its power source any apparatus which is connected to the electrical circuit on which the switch-disconnector is arranged. In particular, actuation of the bridge contact <NUM> in the direction <NUM> causes this electrical separation to occur by way of the physical separation of the bridge contact <NUM> from the first and second contact terminals by the relative motions of the urging member cam and the cam follower.

During the corresponding make operation, the biasing member exerts a restoring force on the cam follower <NUM> and the bridge contact <NUM> in direction <NUM> (see <FIG>). As the moveable member and cam follower are moved back towards the first position, the second surface <NUM> bounding void <NUM> can temporarily contact a second surface 108b of the moveable bridge contact, which contact can help to improve stability of movement of the bridge contact during the make operation (by supporting the middle of the bridge contact, as well as the ends). The force applied by the portions of biasing member <NUM> acting directly on the bridge contact <NUM> (here springs 116a) can help to ensure good electrical contact between the bridge contact <NUM> and the first and second fixed contacts <NUM>, <NUM> when the switch is closed.

Movement of the moveable bridge contact towards the first position by the biasing mechanism (here, the make operation) is at least partially independent of user input. In the examples described herein, the make operation occurs in response to an initial user input (to release the protruding portion from the detent, as discussed above, and thereby release the urging member from the stop position). After rotating the urging member in a second direction opposite to the first direction to rotate the urging member past the stop position, the biasing member <NUM> acts to move the moveable bridge in direction <NUM> towards the first position to close the switch; in particular, the restoring force of the biasing member <NUM> axis direction <NUM> to restore the biasing member from the compression (or tension) to which it has been subject whilst the bridge contact <NUM> was retained in the second position <NUM>. In this regard, the make operation is (for the most part) independent of user input. This arrangement can provide a controlled break operation, and an at least partially independent make operation. This allows the switch make to be achieved quickly, which can be of benefit in applications were rapid electrical connection is required.

The switch disconnector <NUM> of <FIG> and <FIG> is illustrated further in <FIG>. As can be seen from this schematic, the first and second fixed contacts <NUM>, <NUM> are arranged between the cam follower <NUM> and the moveable bridge contact <NUM> (i.e. the bridge contact <NUM> is further away from the cam follower <NUM> in direction <NUM> than the fixed contacts <NUM>, <NUM>).

An alternative switch disconnector is illustrated in <FIG>, in which the moveable bridge contact <NUM> is arranged between the cam follower <NUM> and the first and second fixed contacts <NUM>, <NUM> (i.e. the bridge contact <NUM> is closer to the cam follower <NUM> in direction <NUM> than the fixed contacts <NUM>, <NUM>). In this arrangement, in the first position (where the urging member <NUM> and the cam follower <NUM> are mated and the biasing member <NUM> is under no tension or compression) the moveable bridge contact <NUM> is electrically and physically separate from the first and second fixed contact terminals <NUM>, <NUM> and the current conduction path is open.

Claim 1:
A disconnector (<NUM>), comprising:
a switch (<NUM>) comprising:
a first, fixed, contact terminal (<NUM>) of a first conductor,
a second, fixed, contact terminal (<NUM>) of a second conductor, and
a moveable bridge contact (<NUM>) moveable between a first position (<NUM>) and a second position (<NUM>); and
an actuating mechanism (<NUM>) comprising:
a cam follower (<NUM>) coupled to the moveable bridge contact and comprising a following surface (<NUM>),
a cam (<NUM>) comprising a cam surface (<NUM>), the cam surface configured to engage with the following surface, wherein the cam is rotatable around an axial direction (<NUM>) relative to the cam follower,
wherein at least one of the following surface and the cam surface comprises an angled portion (118a, 120a), the angled portion angled with respect to the axial direction such that rotation of the cam urges the cam follower in the axial direction, wherein the cam follower is configured to move the moveable bridge contact in the axial direction from the first position to the second position in response to the urging, characterised by
two biasing members (116a) configured to, upon movement of the moveable bridge contact in the axial direction, exert a force on the moveable bridge contact in a direction (<NUM>) opposite the axial direction to oppose the movement, one biasing member arranged at each end of the moveable bridge contact.