Patent Description:
Emergency control valves (ECVs), such as those used on domestic gas supply lines, can be difficult to operate by lay people, especially those with physical disabilities.

Typical ECV shut-off arrangements, known in the art per se, generally require special modifications, e.g. to the valve, gas meter, gas infrastructure, etc. For example some previous approaches to make operating an ECV easier have utilised a solenoid-based actuator. However, these are not generally easy to retro-fit to an existing installation. Moreover, a solenoid-based actuator, together with other actuators that require the use of electricity to actuate the ECV, are unsuitable for many gas applications due to the risk of fire or explosion.

In various applications, more generally, it may be desirable to improve the ease of actuation for a valve in a fluid supply line. In many environments, it can be difficult even for a trained service person to access a valve and apply the necessary torque to close the valve.

The present invention seeks to enable those with physical impairments to close off their gas ECV in case of emergency, without the use of electricity. Furthermore, the present invention seeks to assist with valve actuation across a range of applications.

<CIT> describes a safety valve for automatic closing and switching of a valve upon the detection of a fire.

In accordance with aspects, the present invention provides an actuation unit for a valve assembly as defined by claim <NUM> and a valve assembly as defined by claim <NUM>.

Thus it will be appreciated that embodiments of the present invention provide an improved valve assembly in which the valve is retained in the open position until a triggering force is applied by a user. Once triggered, the 'spring-loaded' actuation unit biases the valve to the closed position automatically, i.e. the user does not need to apply any torque to close off the valve. The valve can then be reset by applying a restorative torque in the opposite direction to bring the valve back to the open position, where it is held by latching the driving member. The valve is only latched in the open position when the valve is fully opened (i.e. in the open position). If the restorative torque restores the valve to some intermediate position between the closed and open positions, the latching mechanism has no effect and thus the torque spring biases the valve back to the closed position when the insufficient external torque is no longer applied.

In other words, the force for closing the valve is 'de-coupled' from the force required to open the valve. A user may simply operate the trigger member, which acts to force the valve closed by releasing the torque of the torsion spring. This may be particularly advantageous for users with physical impairments, however it has been appreciated that this may also generally make shutting off the valve easier in installations in which physical access to the valve is restricted (e.g. in closed or unusually shaped spaces).

It will be appreciated that the term 'open position' means that the valve is substantially open, preferably fully open, thereby allowing flow of fluid through the valve. Similarly, the term 'closed position' means that the valve is substantially closed, preferably fully closed, thereby preventing flow of fluid through the valve. Thus the actuation device latches only when the valve is in a position in which the valve is effectively fully open, and does not latch at any intermediate position.

The valve itself may be a new valve that is fitted together with the actuation unit, however the actuation unit may be supplied alone and can be 'retro-fitted' to existing valves that are already in situ, e.g. an existing gas supply valve in a domestic application.

In some embodiments, the valve assembly may make an audible sound when it biases the valve to the closed position. The audible sound may be the sound of a button 'popping up', or may be made by a sonorous component, such as a sonorous metal component (e.g. a bell). This may be beneficial to allow the user to know that the valve has been closed. With a sufficiently audible sound, a telephone operator (e.g. at a remote assistance centre) may be able to hear the valve shut off over the phone so that they are satisfied that the flow of fluid (e.g. domestic gas) has been stopped.

Generally speaking, and in preferred embodiments, the external force required to release the driving member is less than the force that would be required to manually close the valve. Release of the driving member from the latching mechanism allows a relatively large amount of stored energy (i.e. from the torsion spring) to be applied to the operating member of the valve for a potentially relatively small amount of input energy from the user (i.e. to operate the trigger member).

Embodiments in which the force required to close the valve is reduced may be particularly advantageous. However, additionally or alternatively, in some advantageous embodiments the external force applied to the trigger member is a non-rotary force. Some physical impairments may significantly affect the ability of a user to apply a twisting motion (e.g. to twist a valve handle), while the ability to apply a non-rotary force (such as a push or a pull) may not be as severely impaired. Of course, in a set of embodiments, a non-rotary external force may advantageously be less than the rotary force (i.e. the 'first torque') that closes the valve. The non-rotary force may, for example, be a linear force. This non-rotary force may be instantaneous, rather than a continual pushing in of the button, i.e. it is a 'binary' system such that once a sufficient non-rotary force is applied to the trigger member, the valve is triggered closed.

The Applicant has appreciated a number of mechanisms for an externally applied non-rotary force to release the driving member. In some embodiments, the trigger member comprises a button, wherein the driving member is released when the button is pressed. A button may be preferred due to the ease with which a user can press it.

The button itself may comprise a trigger spring arranged to return the button to a normal position after it has been pressed. It will be appreciated that the 'spring' may be any resilient member applying a bias force (e.g. an elastomeric or coil spring). The trigger spring, which may be a compression spring, may also advantageously determine (at least partially) the magnitude of the external force required to trigger the actuation unit into closing the valve, as the force of the trigger spring must be overcome when pressing the button. In some embodiments, a selection of spacers - which may include washers or other suitable components having a particular height or selection of heights - may be added in-line with the trigger spring to 'fine-tune' the amount of force needed to actuate the button. Additionally or alternatively, a nut may be loosened or tightened to adjust the height so as to influence the magnitude of the external force required to trigger the actuation unit into closing the valve. Additionally or alternatively, the trigger spring may be selected from a plurality of trigger springs each having a different respective spring constant. Thus the actuation device may be supplied in a kit together with a choice of trigger springs to allow for fine-tuning of the external force required to trigger the actuation unit into closing the valve.

The button may be positioned conveniently with respect to the actuation unit so as to allow easy access for the user. In some such embodiments, the trigger member comprises a top button positioned such that the top button is actuated by applying a longitudinal force to the top button in a direction parallel to the axis of the valve. In a set of such embodiments, the longitudinal force is to be applied along the axis of the valve, i.e. a coaxial force applied to the top button releases the driving member. Thus, in such embodiments, the axial movement of the button releases the latching mechanism. For example, the driving member may be displaced axially relative to the housing of the actuation unit so as to release the driving member and allow the first torque (from the torsion spring) to drive the valve closed.

In some potentially overlapping embodiments, the trigger member comprises a side button positioned such that the side button is actuated by applying a lateral force to the side button perpendicular to the axis of the valve. In some embodiments, the trigger member comprising a pair of side buttons arranged on opposite sides of the actuation unit. This may, for example, provide a mechanism in which the user 'squeezes' the sides of the unit in order to close the valve. The side button (or each side button) may be a lever. In some such examples, the driving member may be displaced laterally relative to the housing of the actuation unit so as to release the driving member and allow the first torque (from the torsion spring) to drive the valve closed.

Where a button is provided, the button may be located within a button housing. In some embodiments, the latching mechanism may comprise the button housing. Thus, in such embodiments, the driving member may be retained by the button housing until the button is actuated, which may, for example, move the driving member relative to the button housing so as to release the driving member from the latching mechanism.

In addition to buttons, there are other triggering mechanisms that may be used. For example, in some potentially overlapping embodiments, the trigger member comprises a pull tab. The pull tab may, in some embodiments, also provide a latch member against which the driving member is held when held by the latching mechanism, wherein a lateral movement of the pull tab releases the driving member.

Such a pull tab may be pulled from the latched position manually, for example by gripping the tab and pulling it. However, in some embodiments a cord is attached to the pull tab, wherein pulling the cord applies the external force to the pull tab.

However, in some embodiments, the pull tab is attached to a Bowden cable. Those skilled in the art will appreciate that a Bowden cable (sometimes colloquially referred to as a 'brake cable') is a flexible cable that can transmit a pulling force from one end of the cable to the other. Advantageously, this provides a remote actuation method, such that the actuation unit may be triggered into closing the valve from a remote position which could, by way of example only, be metres away from the valve itself. In other arrangements, the Bowden cable may provide remote actuation from a shorter distance, e.g. from just outside a gas meter box, inside of which the actuation device and valve are located. The Bowden cable may, for example, be coupled to a switch, where the switch may be located in a convenient position for user access. By way of non-limiting example, the valve may be placed in a kitchen cabinet, low to the floor and under a kitchen countertop, while the switch may be located on a wall above the countertop.

The driving member is substantially annular. In some embodiments, the driving member is centred on the axis of the valve. By having the driving member centred with respect to the axis of the valve, the forces exerted by the actuation unit are 'balanced' such that no 'twist' is applied across the valve and/or pipe in which the valve is fitted that may cause damage, i.e. the forces exerted are symmetric. In some potentially overlapping embodiments the driving member is seated inside the torsion spring. For example, where a clock spring is used, the driving member may sit inside the innermost coils of the clock spring.

Those skilled in the art will appreciate that a driving member as described herein may be referred to as "an arbor".

The driving member may, at least in some embodiments, comprise a substantially cylindrical component with a ridged portion arranged to hold the driving member in position when latched.

There are a number of ways of latching the driving member such that it holds the valve in the open position. However, in some embodiments, the actuation unit comprises a housing, wherein the driving member (e.g. its ridged portion) is held in abutment against at least a part of said housing when latched. The housing may have a multi-part construction. In some embodiments, the housing may comprise a body portion and/or a lid portion. The part of the housing against which the driving member is held when latched may, at least in some embodiments, be a lid of the housing. Using the housing to hold the driving member in place may be beneficial where a particularly compact arrangement is required.

In embodiments where a lid portion is provided, the lid portion may partially or wholly enclose a cavity defined by the body portion (i.e. it may be a 'complete' lid in which the cavity is wholly enclosed, or a 'partial' lid in which there is at least one gap between the cavity and the outside world). For example, in embodiments in which a tab is provided that may be pulled in order to release the driving member as described in further detail below), the lid may partially enclose the cavity defined by the body portion, where the tab completely encloses the cavity when latched.

In some such embodiments, the latching mechanism comprises a tab that, when latched, is held in abutment against a stop face. When the external force is applied to the trigger member (e.g. the tab is pulled away from the stop face), the driving member is released and the valve is driven to the closed position. As will be understood by those skilled in the art, a latching mechanism is typically constructed from a 'latch' (a part that moves and can be held) and a 'keeper' (a part that is static and holds the latch). In some such embodiments, the tab and stop face may be the latch and keeper respectively, or vice versa.

In a set of embodiments, the stop face is provided on the housing, e.g. on a part of the lid portion.

In a set of potentially overlapping embodiments, the tab is provided on the driving member. However, in some embodiments, the tab is provided on the trigger member, wherein the trigger member mechanically engages the driving member such that both the trigger member and driving member rotate about the axis of the valve together. For example, the tab may be provided on the button housing in one set of embodiments as described herein. Rather than having the trigger member mechanically engage the driving member, arrangements are envisaged in which the trigger member and driving member are of integral construction.

In some embodiments, the latching mechanism is arranged to direct a portion of the external force applied to the trigger member as a rotational force applied to the driving member. For example, where the trigger member comprises a top button, a portion of the longitudinal force applied to the top button in the direction parallel to the axis of the valve may be translated to a rotational force applied to the driving member.

The Applicant has appreciated different mechanisms for providing this translation of a non-rotational force to a rotational force. In some embodiments in which the driving member comprises a tab as outlined above, the tab may comprise a chamfered side surface at an oblique angle to the axis about which the valve rotates, wherein the chamfered side surface of the tab abuts the stop face when the driving member is held by the latching mechanism. In some potentially overlapping embodiments, the stop face of the housing comprises a chamfered side surface at an oblique angle to the axis about which the valve rotates, wherein the chamfered side surface of the stop face abuts the tab when the driving member is held by the latching mechanism. Preferably, the tab and stop face each comprise a chamfered side surface, wherein the chamfered side surface of the tab corresponds to the chamfered side surface of the stop face, i.e. their sloped side surfaces (that touch when latched) match one another. In a potentially overlapping set of embodiments, the tab may comprise a chamfered front surface.

Those skilled in the art will appreciate that the term 'chamfered' as used herein means that the tab and/or stop face may have a wedge-like construction. The Applicant has appreciated that such an arrangement is particularly advantageous because it may make triggering the release of the driving member easier for a user. This effect is achieved because the slope of the tab and/or stop face (and preferably both) translates a component of the lateral force from the torsion spring to a downward force such that, once the trigger member starts to move, the force of the torsion spring 'assists' the trigger members motion. The tab and/or stop face may each have a pair of chamfered side surfaces, such that the movement of one past the other is made easier regardless of whether the rotation about the axis is clockwise or anti-clockwise.

The oblique angle of the slope (the angle between the normal to the surface and the axis around which the valve rotates) will depend on force requirements and an appropriate selection can be made, however in some embodiments, the angle of the slope may be equal to or less than approximately <NUM>°, optionally equal to or less than approximately <NUM>°, and preferably equal to or less than approximately <NUM>°. In a set of embodiments, the angle of the slope is between approximately <NUM>° and <NUM>°, for example between approximately <NUM>° and <NUM>°, preferably between approximately <NUM> and <NUM>°, and most preferably between approximately <NUM>° and <NUM>°.

In a potentially overlapping set of embodiments the tab and/or stop face may have a curve-like construction in which the tab and/or stop face may each have a pair of curved side surfaces. Thus the tab may, in some embodiments, comprise a curved side surface having a varying angle to the axis about which the valve rotates across said curved surface, wherein the curved side surface of the tab abuts the stop face when the driving member is held by the latching mechanism. In some potentially overlapping embodiments, the stop face of the housing comprises a curved side surface having a varying angle to the axis about which the valve rotates across said curved surface, wherein the curved side surface of the stop face abuts the tab when the driving member is held by the latching mechanism. Preferably, the tab and stop face each comprise a curved side surface, wherein the chamfered side surface of the tab corresponds to the curved side surface of the stop face, i.e. their sloped side surfaces (that touch when latched) match one another. In a potentially overlapping set of embodiments, the tab may comprise a curved front surface.

Those skilled in the art will appreciate that this may provide a screw-thread like construction, where the 'thread pitch' may be relatively coarse. Such an arrangement may advantageously ease turning of the driving member.

The valve may be any of a number of valves which rotate between an open position and a closed position. However, in some embodiments, the valve is a quarter-turn valve. Those skilled in the art will appreciate that a 'quarter-turn' valve is a valve having substantially <NUM>° between its open and closed positions. In some such embodiments, the valve is a ball valve. However, it will be appreciated that the principles of the present invention could also be applied to, for example, disc valves, vane valves, plug valves, etc..

In some embodiments, the valve comprises a gas supply valve, preferably a domestic gas supply valve. The gas supply valve may be positioned in-line on a domestic gas supply pipe. The gas supply valve may, in some embodiments, be a 'standard' gas supply valve, i.e. the valve may be manufactured in accordance with a relevant standard, as determined by an appropriate standards board. Alternatively, the valve may comprise a water supply valve or any other suitable valve for controlling fluid flow (i.e. of a liquid or gas supply).

Those skilled in the art will appreciate that a torsion spring is a type of spring arranged to store mechanical energy by twisting it. When a torsion spring is twisted, it exerts a torque in the rotational direction opposite to the rotational direction of twisting. The resulting torque is generally proportional to the angle through which the spring is twisted. One type of torsion spring that may be used is a helical torsion spring, where a wire or rod is bent into a coil, where a twisting motion applied to its ends (i.e. an applied bending moment) causes the coil to be twisted tighter. However, in some embodiments, the torsion spring comprises a clock spring, sometimes referred to as a 'spiral wound torsion spring' or a 'power spring'. Unlike a helical spring, a clock spring is wound in a concentric spiral (i.e. it has 'in-plane' windings), such that the spring has a relatively 'flat' profile. This may be particularly advantageous in constructing a compact actuation unit suitable for use in physically restricted or 'cramped' conditions.

The actuation unit may, in some embodiments, comprise a sacrificial element arranged to release the driving member such that it is no longer held by the latching mechanism. This may, for example, comprise a component that dissolves in a flood or melts in a fire, allowing automatic triggering of the valve to the closed position without user input. Additionally or alternatively, a component may be arranged to physically break when overpowered with a particular input force, e.g. if the valve is forced closed manually.

Thus, the latching mechanism may hold the driving member at positions other than in the open position, for example at an intermediate position. This may, by way of non-limiting example, be useful for water valves which may be latched at an intermediate position between the 'fully' open and 'fully' closed positions, where a sacrificial element is arranged to release the latching mechanism in response to a flood.

In some arrangements, the driving member is positioned on a fire protection member, said fire protection member having a melting point lower than a melting point of the driving member, wherein the fire protection member is arranged such that, when the driving member when latched, the fire protection member releases the driving member upon the fire protection member melting. The fire protection member may, for example, be a washer such as a plastic washer. Alternatively, where the triggering member comprises a pull tab, a portion of the pull tab may be arranged to melt when exposed to a sufficiently high temperature, thereby releasing the driving member.

The sacrificial element may be arranged to break when exposed to a fire, e.g. when exposed to a temperature exceeding some threshold limit. Such a sacrificial element may be frangible. In a set of such embodiments of either of the foregoing aspects of the invention, the sacrificial element comprises a glass bulb. The temperature threshold of the bulb may, for example, depend on the geometry of the bulb and/or a fluid composition within the bulb (e.g. a liquid and/or gas inside the bulb that expands when exposed to sufficient heat energy). The Applicant has appreciated that it is advantageous to use a frangible glass bulb (similar to frangible glass bulbs used in fire sprinkler systems) in order to provide a heat-activated valve, e.g. to close a gas supply valve in the event of a fire.

In normal operation, the latching mechanism may be held in abutment against the glass bulb, wherein breaking of the bulb causes the latching mechanism to be released. Such an arrangement may advantageously bias the valve to the closed position in response to exposure to a fire.

In a set of such embodiments, the latching mechanism may comprise a bulb retainer that, in normal operation, is held in abutment between the glass bulb and the driving member. In other words, the bulb retainer may resist the spring force of the driving member so long as the glass bulb remains intact.

Once assembled, one side of the bulb is held in contact with the bulb retainer. The opposite side of the bulb may be held in place by a bulb holding portion, which may for example be a suitable slot (e.g. a milled slot) located on the lid of the housing. The bulb retainer may, in some embodiments, comprise a pivot arm arranged to pivot around a pivot axis when the glass bulb breaks. This pivot arm may therefore be held against the spring force of the driving member, where the driving member can push the pivot arm out of the way upon the glass bulb breaking.

The pivot axis may extend parallel to the axis of the valve, i.e. such that the plane in which the pivot arm rotates is parallel to the plane in which the valve rotates.

While the trigger mechanism could be the only way by which the valve can be closed, in a set of embodiments, the valve assembly is arranged that an external third torque in the first rotational direction closes the valve. There may, in some such embodiments, be a threshold amount of force required to 'overcome' the resistance of the driving member when latched before the valve can be forced closed. This may be advantageous where a person (e.g. a firefighter) may need to manually close the valve. As outlined above, the actuation unit may comprise a sacrificial element that breaks when a user applies an external torque in the first rotational direction greater than a threshold to the valve assembly, e.g. to overpower the force of the torsion spring and close the valve manually.

It will be appreciated that the device described herein works regardless of whether closing the valve requires a clockwise rotation or an anti-clockwise rotation, i.e. the first rotational direction may be clockwise and the second rotational direction may be anti-clockwise, or vice versa. In some embodiments, the torsion spring is invertible, such that the respective directions of the first and second rotational directions may be swapped. For example, where a clock spring is used, the clock spring may, in such embodiments, be flipped over. In some embodiments, the torsion spring is sealed within a housing, and so the determination of the directions is made during manufacturing, however other arrangements are envisaged in which the torsion spring may be placed in the desired orientation during installation so as to fit a particular end-use.

In some embodiments, the operating member of the valve comprises a stem that extends along the axis of the valve. Such a stem may, for example, be threaded. Additionally or alternatively, the operating member of the valve may comprise a handle, e.g. extending laterally from the stem. The driving member may be physically attached to the operating member, for example attached to the stem or the handle of the valve.

In some embodiments, the valve assembly comprises a visual indicator that indicates when the valve is in the open position and when the valve is in the closed position. This can be helpful to allow a user to easily see at a glance the current operating state of the valve.

For example, in embodiments where the operating member of the valve comprises a handle, the handle may aid identification of the operating state of the valve. In some embodiments, a first visual marker indicates the open position and a second visual marker indicates the closed position, wherein in the open position, the handle covers the second visual marker, and wherein in the closed position, the handle covers the first visual marker. In some such embodiments, the handle is elongate, wherein a portion of the elongate handle obscures the first and second visual markers in the appropriate positions. It will be appreciated that visual markers include any suitable verbal or symbolic visual markers including: the words 'ON' and 'OFF'; the words 'OPEN' and 'CLOSED'; the numbers '<NUM>' and '<NUM>'; symbols such as a tick and a cross; illustrative symbols showing a valve being open or closed; illustrative symbols showing fluid flow and no fluid flow; colour coding; arrows; etc..

In some embodiments, the actuation unit comprises an engagement portion arranged to engage with a pipe. This engagement portion acts as a 'strap' such that, where the valve is connected in-line with a pipe, the actuation unit can be fixed around the valve and affixed to the pipe. The engagement portion could comprise a removable piece that is positioned on the opposite side of the pipe to the rest of the actuation unit, where these are then fixed together by a suitable fastening means, e.g. screws or a nut and bolt arrangement. The removable piece and the actuation unit (e.g. a housing of the actuation unit) may be supplied with through-holes that align when the removable piece is in place, where a suitable fastener may hold this in place.

The removable piece may be 'U-shaped' (i.e. of a horseshoe-like construction) that forms a collar around the pipe when affixed.

In a set of such embodiments, the engagement portion may comprise a hinged portion. Providing a hinged mechanism may advantageously allow the actuation unit to be easily clamped around the valve and affixed to the pipe and for easy removal of the actuation unit from the pipe. The actuation unit may have a 'double hinge', where the hinge can open on two opposite sides of the actuation unit so as to allow placement around pipes in different spaces. Arrangements are envisaged in which a removable piece with through holes may be fixed to the housing of the actuator through one of the sets of through-holes thereby forming the hinge, however in other arrangements a dedicated hinge may be provided.

The torsion spring may come 'pre-loaded' in the valve assembly such that the valve assembly is assembled onto a valve when the valve is in the closed position. Once assembled, the valve is then moved to the open position (e.g. with a manual <NUM>° turn to the open position).

In some embodiments, a safety cover may be provided that contains the rest of the valve assembly, wherein the trigger member may be accessed through the safety cover (e.g. a button may protrude through the safety cover). The safety cover may, in a set of embodiments, comprise a transparent window through which the handle of the valve may be seen, thereby providing a visual indication of whether or not the valve is closed. The safety cover may be locked closed around the valve assembly, preventing the valve from being re-opened after it is triggered without the key to the safety cover. Such a key may, for example, only be held by authorised persons such as gas engineers or firefighters.

Certain embodiments of the present invention will now be described with reference to the accompanying drawings, in which:.

<FIG> are schematic drawings of a quarter-turn valve <NUM>, while <FIG> are cross-sectional drawings of the valve <NUM> of <FIG>. In particular, the valve <NUM> shown is a quarter-turn ball valve, as outlined in further detail below.

The valve <NUM> comprises a valve housing <NUM>, with two fluid apertures <NUM>, <NUM> which allow ingress of a fluid, i.e. a liquid or a gas, into the valve <NUM>. An operating member <NUM> is arranged to rotate a quarter turn between an 'on' position (as shown in <FIG> and <FIG>) in which fluid may flow freely through the valve <NUM>, and an 'off' position (as shown in <FIG> and <FIG>) in which the fluid is prevented from flowing through the valve <NUM>. Typically, a handle (not shown) is attached to a stem <NUM>, which may be threaded, such that rotation of the handle rotates the stem <NUM> about an axis, thereby rotating a ball <NUM> within the valve housing <NUM> about the axis of the stem <NUM>.

The ball <NUM> has a hollow cylinder <NUM> running through it, such that in the on position, the flow axis of the hollow cylinder <NUM> is aligned with the axis of the valve <NUM> such that fluid may pass through the valve <NUM>. In the off position, however, the flow axis of the hollow cylinder <NUM> is perpendicular to the flow axis of the valve <NUM>, such that there is no fluid flow path, thereby preventing flow of the fluid.

It will be appreciated that intermediate positions between the on and off positions may reduce but not completely inhibit fluid flow, however generally an emergency valve such as an emergency domestic gas shut off valve is either 'on' or 'off', with intermediate positions being undesirable for safety reasons well understood by those skilled in the art.

<FIG> are schematic drawings that show an actuation unit <NUM> with a top button <NUM> in accordance with an embodiment of the present invention including the handle used to operate the valve <NUM>. The internal construction of the actuation unit <NUM> may be readily understood with reference to <FIG>. Briefly, <FIG> and <FIG> provide exploded views of the actuation unit <NUM>, and <FIG> is a cross-sectional view of the actuation unit <NUM>.

The actuation unit <NUM> is constructed from a housing <NUM> fitted a lid <NUM>, a top button <NUM> (i.e. a trigger member) including a button inner <NUM> which is positioned within, and is movable vertically relative to, a button housing <NUM>. The button housing <NUM> is also moveable vertically relative to the housing <NUM>, as explained in further detail below.

A hinged portion <NUM> is positioned at the bottom of the actuation unit <NUM>, and 'hinges' away from the housing <NUM>. This hinged portion <NUM> acts as a 'strap' such that, where the valve <NUM> is connected in-line with a pipe (not shown), the hinged portion <NUM> allows the actuation unit <NUM> to be clamped around the valve <NUM> and affixed to the pipe. This hinged portion <NUM> may be 'double hinged', such that the strap may open in either direction, as different installations may require that the strap open one direction or the other in order to fit it around the pipe. It will of course be appreciated that other arrangements are possible, e.g. the hinged portion <NUM> could instead be a wholly separate piece that is screwed or bolted to the housing <NUM> once the actuation unit <NUM> is in place.

The handle <NUM> may be supplied as part of the actuation unit <NUM> or may be an existing handle associated with the valve <NUM> which is removed when the actuation unit <NUM> is fitted, and then re-attached once the actuation unit <NUM> is in place. A tab-shaped protrusion <NUM> extends from an outer surface of the button housing <NUM> and is arranged to latch against the housing <NUM> of the actuation unit <NUM>, as outlined in further detail below.

The button housing <NUM> engages with the operating member <NUM> of the valve <NUM>, specifically with the stem <NUM>, via an arbor <NUM> as outlined in further detail below. It will be appreciated that in other embodiments, the button housing <NUM> may additionally or alternatively engage with the handle <NUM> (again, via the arbor <NUM> outlined below) which, in turn, engages the stem <NUM>.

Two side tabs <NUM> extend from the button housing <NUM>, though these could form part of the handle <NUM> in some embodiments, e.g. the handle <NUM> and side tabs <NUM> could be of integral construction. An 'on' indicator <NUM> and an 'off' indicator <NUM> are located on the upper face of the lid <NUM>. Depending on whether the valve <NUM> is in the open or closed position, only one of these indicators <NUM>, <NUM> is visible at a time, the other indicator <NUM>, <NUM> being covered by the side tabs <NUM>. This allows a user to easily see at a glance the current operating state of the valve <NUM>, i.e. whether it is open or closed. In the illustrated embodiment, the 'on' indicator <NUM> and an 'off' indicator <NUM> are the words 'ON' and 'OFF' respectively, however it will be appreciated that these indicators may be any other form of verbal or symbolic indicator, for example colours, symbols, pictograms, words, letters, ticks/crosses, etc. as appropriate.

As will be explained in further detail below, pushing the button <NUM> in the downward direction <NUM> (i.e. vertically relative to the button housing <NUM>) releases a driving member from a latch, causing the driving member to force the valve <NUM> from the open position (see <FIG>, <FIG>, and <FIG>) to the closed position (see <FIG>, <FIG>, and <FIG>), by rotating the operating member <NUM> of the valve <NUM> around its axis, i.e. in a rotational direction <NUM>. The mechanism that achieves this may be readily understood by reference to <FIG>, <FIG>, and <FIG>.

Within the housing <NUM> is located a torsion spring <NUM> and an arbor <NUM> (i.e. a driving member). The torsion spring <NUM> has a tab 38a, 38b at each end of the spring <NUM>. The outermost tab 38a is, when assembled, held in place in a slot <NUM> of the housing <NUM>. The housing <NUM> may be provided with a number of these slots <NUM>, such that the 'built in' torsion of the torsion spring <NUM> (i.e. a 'torsional pre-load force') may be adjusted by placing the tab 38a in a particular slot <NUM>. The innermost tab 38b is, when assembled, held in place in a slot <NUM> of the arbor <NUM>. Thus, rotating the arbor <NUM> relative to the housing <NUM> varies the torsion of the torsion spring <NUM>, storing energy within the spring <NUM>.

When the valve <NUM> is in the closed position, a user must apply a sufficient external torque in order to reset the valve <NUM> to the open position. In order to achieve this, the user applies a force to the handle <NUM>, which is coupled to the arbor <NUM>, which in turn is coupled to the operating member <NUM> of the valve <NUM>. As the arbor <NUM> is rotated relative to the housing <NUM> in response to an external torque applied to the handle <NUM>, the operating member <NUM> of the valve <NUM> rotates from the closed position to the open position as shown in <FIG>. Once in the open position, the button inner <NUM> is free to 'pop up' as shown in <FIG>, changing the distance between the top surface of the button inner <NUM> and the button housing <NUM> from d1 to d2, causing an audible 'click' that the user can hear.

Once the open position is reached, the arbor <NUM> is held in place by the housing <NUM>. Thus the arbor <NUM> is 'latched' by the housing <NUM> until the button <NUM> is pressed.

As can be seen in <FIG>, the button <NUM> has a tapered triggering tab <NUM> that, when the valve <NUM> is in the open position, abuts a tapered stop face <NUM> on the main body assembly. In this example, the tapered stop face <NUM> is on the lid portion <NUM>. This operation may be understood with further reference to <FIG> as outlined in further detail below.

The tab <NUM> has a pair of chamfered side surfaces <NUM> which are each at an oblique angle to the axis about which the valve <NUM> rotates. The chamfered side surfaces <NUM> of the tab <NUM> abut corresponding chamfered side surfaces <NUM> of the stop face <NUM> when the arbor <NUM> is held by the latching mechanism. The tab also comprises a chamfered front surface <NUM>. The chamfered side surfaces <NUM> of the tab <NUM> and the chamfered side surfaces <NUM> of the stop face <NUM> correspond to one another such that their sloped side surfaces <NUM>, <NUM> substantially match one another.

This means a portion of the torque <NUM> from the torsion spring <NUM> creates a downward force component on the button <NUM> to compensate for friction, making depressing the button <NUM> easier than it would be without the taper. The button <NUM> is supported by a trigger spring <NUM>. By adjusting the trigger spring force, the force required to depress the button <NUM> can be adjusted.

Additionally, the taper can be chosen so that the valve <NUM> can be closed with the lever arm, without using the button. This will require high torque but may prevent damage to the valve if the handle <NUM> is forced while ultimately allowing the valve <NUM> to be closed.

An overview of operation when the button <NUM> is pressed can be seen in <FIG>, with further reference to <FIG>. For reference, a cross-section of the actuation unit <NUM> is shown in <FIG>.

<FIG> shows the actuation unit <NUM> when the valve <NUM> is in the open position, without the button assembly visible for ease of understanding. In this position, the valve <NUM> is held in the open position, because the arbor <NUM> is latched as outlined above. As can be seen in <FIG>, in the open position, the rotational force <NUM> of the torsion spring <NUM> cannot close the valve because of the latching mechanism, i.e. the tab <NUM> on the button housing <NUM> is held in abutment against the stop face <NUM>. The tab <NUM> is biased upwards by the trigger spring <NUM>.

The user then presses down the button <NUM> by applying an 'axial' force <NUM>, i.e. along the axis of the operating member <NUM> of the valve <NUM>, as shown in <FIG>, compressing the trigger spring <NUM>. As can be seen in <FIG>, this moves the tab <NUM> downwards relative to the stop face <NUM>. Due to the chamfered side surfaces <NUM>, <NUM> of the tab <NUM> and stop face <NUM>, a component <NUM> of the rotational force <NUM> provided by the torsion spring assists with the downward motion of the tab <NUM>.

This allows the tab <NUM> on the button housing <NUM> to pass under the stop face <NUM> of the housing <NUM>, releasing the arbor <NUM> from the latching mechanism and permitting the torsion spring <NUM> to impart a rotational force <NUM> on the arbor <NUM>, as shown in <FIG>.

Once the tab <NUM> has moved sufficiently downwards relative to the stop face <NUM> as shown in <FIG>, the tab <NUM> passes under the stop face <NUM> as shown in <FIG>. The rotational force <NUM> is then free to bias the valve <NUM> to the closed position, as shown in <FIG>.

Once in the closed position, the trigger spring <NUM> imparts an upward axial force <NUM>, which pops the button <NUM> up as shown in <FIG> and <FIG>, and the tab <NUM> moves upward relative to the stop face <NUM>, on the other side of the stop face <NUM> having gone through a rotation of <NUM>°. The button <NUM> moving upwards may make an audible click which may indicate to the user that the valve is closed. This click may be sufficiently loud that it may be heard over a telephone, e.g. by a telephone operator talking the user through shutting off the gas supply.

<FIG> is a cross-sectional drawing showing a fire protection mechanism within the actuation unit <NUM>. <FIG> are schematic drawings illustrating operation of fire protection mechanisms. Specifically, <FIG> illustrate operation of the protection mechanism of <FIG>, while <FIG> shows an alternative construction.

In this embodiment, a thermal washer <NUM> having a selected melting temperature is provided between the button inner <NUM> and a lip <NUM> of the button housing <NUM> on which the button inner <NUM> rests, as can be seen in <FIG>.

This thermal washer <NUM> acts as fuse by failing at a specific high temperature, i.e. its melting point, such that it melts. When the thermal washer <NUM> melts as shown in <FIG>, this allows the button <NUM> to move upwards in response to the force <NUM> from the trigger spring <NUM>, allowing the button <NUM> to pass over the button inner <NUM>, forced upwards by the trigger spring <NUM>. Once the button <NUM> has moved upwards, the arbor <NUM> is free to rotate and is forced by the torsion spring <NUM> to close the emergency control valve <NUM>.

<FIG> shows an alternative construction in which like reference numerals appended with a prime symbol (') denote like components. As can be seen in <FIG>, the thermal washer <NUM>' may be placed at an angle, rather than flat, with a suitable slope of the lip <NUM>' of the button housing <NUM>'. This sloping of the thermal washer <NUM>' may advantageously help to prevent the button <NUM> getting caught in case of less-than-optimal concentricity or uneven loading.

<FIG> are schematic diagrams showing an alternative sacrificial triggering mechanism in which like reference numerals appended with a double prime symbol (") denote like components. In this arrangement, the tab <NUM>" of the button housing <NUM>" is held in place by a fixed stop feature <NUM>", which prevents the rotation of the button housing <NUM>" and associated arbor (not shown) under the rotational force <NUM>" of the torsion spring (not shown).

The stop feature <NUM>" has a sacrificial part <NUM>" which melts when exposed to a sufficiently high temperature, such that it no longer holds the tab <NUM>" of the button housing <NUM>", thereby allowing rotation of the button housing <NUM>" and associated arbor (not shown) under the influence of the torsion spring (not shown), i.e. in response to the rotational force <NUM>".

<FIG> are schematic drawings that show an alternative actuation unit <NUM> with a side button <NUM> in accordance with a further embodiment of the present invention. <FIG> are further schematic drawings illustrating operation of the actuation unit <NUM> of <FIG>.

In addition to the top button <NUM>, which operates in the same way as described above, the actuation unit <NUM> is provided with a pair of side buttons 170a, 170b arranged to trigger release of the arbor <NUM> in response to a lateral force <NUM> applied by the user, i.e. in response to one or both of the side buttons 170a, 170b being pushed or squeezed against the restorative force from corresponding side button springs 171a, 171ab.

In the actuation unit <NUM>, a bypass plate <NUM> is provided which, if moved, releases the latching mechanism such that the arbor <NUM> and top button assembly <NUM> (together with the associated handle <NUM>) to rotate around the axis of the valve, driving the valve to the closed position.

In <FIG> and <FIG>, the valve is in the open position, and the bypass plate <NUM> holds the arbor <NUM> in place. However, when the user presses either side button 170a, 170b by applying a lateral force <NUM>, this causes the bypass plate to move in a radial direction <NUM> away from the arbor <NUM>, releasing the tab <NUM> of the button housing <NUM>.

This can be seen in <FIG> and <FIG>, in which the bypass plate <NUM> moves backwards, allowing the tab <NUM> on the button housing to pass and thus the arbor <NUM>, button housing <NUM>, and handle <NUM> to rotate about the axis of the operating member of the valve in a rotational direction <NUM> about the axis of the valve's operating member.

Once the valve is in the closed position as shown in <FIG> and <FIG>, an extruded boss <NUM> on the arbor <NUM> prevents the bypass plate <NUM> from returning to its forward position.

<FIG> is a schematic drawing that shows an actuation unit <NUM> with a pull-tab trigger mechanism in accordance with a further embodiment of the present invention. <FIG> are schematic drawings that show this actuation unit <NUM> connected to a Bowden cable trigger mechanism.

Similarly to the actuation unit <NUM> described previously with reference to <FIG> and <FIG>, a bypass plate <NUM> provides a latching mechanism by which the arbor <NUM> is held in place. The actuation unit <NUM> has a top button <NUM> trigger and handle <NUM> which operate in the same way described with reference to the actuation unit <NUM> of <FIG>. Similarly, the actuation unit <NUM> also has side buttons 270a, 270b that can move the bypass plate <NUM> backwards in the manner described previous with reference to the actuation unit <NUM> of <FIG> and <FIG>.

In this arrangement there is a remote terminal <NUM> with a button <NUM> and an indicator <NUM>. The button <NUM> can be used to trigger release of the latching mechanism, thereby closing the valve, as explained below. The indicator <NUM> provides a visual indication of whether the gas is on or off (i.e. whether the valve is open or closed respectively).

As can be seen in <FIG>, initially the gas is on as indicated by the indicator <NUM>. When a user presses the external button <NUM> by applying a force <NUM>, the inner core of a Bowden cable <NUM>, attached to the button <NUM>, is pulled, i.e. it applies a lateral force <NUM> to the bypass plate <NUM>. The other end of the inner core of the Bowden cable <NUM> is connected to the bypass plate <NUM>, which acts as a pull tab.

As shown in <FIG>, the bypass plate <NUM> therefore moves backwards, away from the arbor <NUM>, allowing button tab to pass and thus the arbor <NUM> to rotate in the rotational direction <NUM>, therefore driving the operating member of the valve toward the closed position. During this motion, the arrow on the indicator <NUM> indicates that the valve is not fully closed.

As can be seen in <FIG>, and similarly to the corresponding feature described with respect to the actuation unit <NUM> of <FIG> and <FIG>, an extruded boss on the arbor <NUM> prevents the bypass plate <NUM> from returning to its forward position. The arrow on the indicator <NUM> indicates that the valve is still not fully closed.

The extruded boss on the arbor <NUM> is stepped towards the end of its travel which allows for further movement of the bypass plate <NUM>. This allows more accurate indication at the remote terminal <NUM> that the valve is fully closed, as shown in <FIG>.

<FIG> are cross-sectional drawings showing the remote terminal <NUM> in more detail. Within a housing <NUM> of the remote terminal <NUM> is located a pair of rotating arms <NUM> and a tensioning spring <NUM> which is arranged to maintain the button position once the bypass plate <NUM> is in the not return position and to ensure the indicator <NUM> is correctly registering lever position and valve state. The rotating arms <NUM> translate a vertical movement of the button <NUM> to a horizontal movement of the Bowden cable carrier <NUM>. This spring <NUM> must be lower in force than the side button springs 271a, 271b so that the button remains in the up position when the bypass plate is in the locked position.

The button <NUM> only returns to the up position once the valve is turned to the open position, i.e. when the gas is on. In this position, the bypass plate <NUM> can return under the action of the side button springs to the locked position. The side button springs 271a, 271b push the side buttons 270a, 270b outwards, and pivot around their connection point with the housing of the actuation unit <NUM>. This pushes the bypass plate <NUM> forwards, back to the locked position.

<FIG> are cross-sectional drawings that show an alternative mechanism that allows for the valve to be closed manually. In this arrangement, the button <NUM> has a curved triggering tab <NUM> that, when the valve <NUM> is in the open position, abuts a curved stop face on the main body assembly (not shown).

The tab <NUM> has a pair of curved side surfaces <NUM> which are each curved with respect to the axis <NUM> about which the valve rotates, such that the angle θ<NUM>, θ<NUM> between the normal to the curved surfaces <NUM> and the axis <NUM> varies across the curved surfaces <NUM>. The curved side surfaces <NUM> of the tab <NUM> abut corresponding curved side surfaces of the stop face when the arbor is held by the latching mechanism. The curved side surfaces <NUM> of the tab <NUM> and the curved side surfaces of the stop face correspond to one another such that their sloped side surfaces substantially match one another, mating in a similar way to a coarse screw thread.

<FIG> are schematic drawings of an actuation unit <NUM> with a sacrificial triggering mechanism that uses a frangible glass bulb <NUM> in accordance with a further embodiment of the present invention.

In this particular arrangement, the sacrificial element which provides fire protection is a frangible glass bulb <NUM> arranged to break when exposed to a fire. When exposed to a temperature exceeding a threshold amount (i.e. a degree of heat associated with the presence of fire), a heat-sensitive fluid (typically a liquid) inside the glass bulb <NUM> rapidly expands, causing the bulb <NUM> to shatter. The temperature at which the bulb <NUM> breaks generally depends on the geometry of the bulb <NUM> and/or the composition of the fluid within the bulb <NUM>.

In addition to the latching mechanisms described previously, in this embodiment a pivot arm <NUM> is positioned between the glass bulb <NUM> and the arbor (i.e. the driving member) such that it is in contact with both when fully assembled, as shown in <FIG>. Specifically, when fully assembled, one side of the bulb <NUM> is held in contact with the pivot arm <NUM> (i.e. the bulb retainer).

The opposite side of the bulb <NUM>, which is tapered, is held within a suitably sized milled slot <NUM> which is located on the lid <NUM> of the housing <NUM>. Thus the milled slot <NUM> acts as a 'socket' for the bulb <NUM>.

The pivot arm <NUM> is mounted to the lid <NUM> of the housing <NUM> via a suitable pivot point <NUM>, e.g. a dowel or hinge point, such that the pivot arm <NUM> may rotate about the pivot point <NUM>. Thus the pivot point <NUM> provides the axis of rotation for the pivot arm <NUM>. The axis of the pivot point <NUM> is generally normal to the plane of the housing lid <NUM>, and thus parallel to the axis of rotation of the valve.

<FIG> are further schematic drawings illustrating the operation of the sacrificial glass bulb triggering mechanism of <FIG>. In particular, <FIG> shows the actuation unit <NUM> under normal operation, when the unit <NUM> is fully assembled. As can be seen in <FIG>, the pivot arm <NUM> is held in abutment between the glass bulb <NUM> and the arbor <NUM>.

This pivot arm <NUM> is therefore 'wedged' between the bulb and the arbor <NUM> so as to prevent rotation of the arbor <NUM>. Of course, the arbor <NUM> may still rotate in response to the other methods of releasing the latching mechanism outlined above as appropriate (e.g. in response to a button being pressed, a tab being pulled out, etc.). Thus so long as the glass bulb <NUM> remains intact (i.e. there has been no fire) the pivot arm <NUM> resists the rotational spring force being applied to the arbor <NUM> by the internal spring, where this rotational force has been discussed previously.

As can be seen in <FIG>, when exposed to sufficient heat (e.g. during a fire), the glass bulb breaks. As a result, the pivot arm <NUM> is then free to rotate and occupy space previously occupied by the glass bulb <NUM>. With the resistance from the glass bulb <NUM> removed, the arbor <NUM> pushes the pivot arm <NUM> out of the way (i.e. it 'swings around' the pivot point <NUM>) under the force from the spring within the actuation unit <NUM>.

This results in the valve to which the actuation unit <NUM> is connected - which is mechanically coupled to the arbor <NUM> - to rotate in the manner described previously, thereby biasing the valve to the closed position. This may be particularly advantageous, for example, for shutting off the domestic gas supply during a fire, thereby limiting the risk of flammable gas from coming into contact with the flames.

Claim 1:
An actuation unit (<NUM>; <NUM>; <NUM>) for a valve assembly, the actuation unit comprising:
a torsion spring (<NUM>), a trigger member (<NUM>; <NUM>; <NUM>'; <NUM>; 170a, 170b; 270a, 270b; <NUM>), a latching mechanism (<NUM>; <NUM>; <NUM>; <NUM>"; <NUM>; <NUM>) and a driving member (<NUM>; <NUM>; <NUM>; <NUM>), said driving member (<NUM>; <NUM>; <NUM>; <NUM>) being arranged to engage with an operating member (<NUM>) of a valve (<NUM>) to drive rotation of the operating member (<NUM>), wherein the torsion spring (<NUM>) applies a first torque to the driving member (<NUM>; <NUM>; <NUM>; <NUM>) around an axis in a first rotational direction;
wherein an external second torque applied opposite to the first torque resets the valve (<NUM>) to an open position in which the driving member (<NUM>; <NUM>; <NUM>; <NUM>) is held by the latching mechanism (<NUM>; <NUM>; <NUM>; <NUM>"; <NUM>; <NUM>), thereby resisting the first torque of the torsion spring (<NUM>), said latching mechanism (<NUM>; <NUM>; <NUM>; <NUM>"; <NUM>; <NUM>) being arranged to hold the driving member (<NUM>; <NUM>; <NUM>; <NUM>) only when the valve (<NUM>) is in the open position;
wherein an external force applied to the trigger member (<NUM>; <NUM>; <NUM>"; <NUM>; <NUM>; <NUM>; 170a, 170b; 270a, 270b; <NUM>) releases the driving member (<NUM>; <NUM>; <NUM>; <NUM>) such that it is no longer held by the latching mechanism (<NUM>; <NUM>; <NUM>; <NUM>"; <NUM>; <NUM>), the first torque thereby rotating the driving member (<NUM>; <NUM>; <NUM>; <NUM>) in the first rotational direction so as to drive rotation of the operating member (<NUM>) and mechanically bias the valve (<NUM>) to the closed position; and characterised in that:
the driving member (<NUM>; <NUM>; <NUM>; <NUM>) is substantially annular.