A gearbox for a valve and method of installation thereof

Abstract

A gearbox 1 for a valve 2, the gearbox comprising a housing 3, a gear arrangement comprising an input gear 30 and an output gear 8 connected to an output gear mounting member such that rotation of the output gear rotates the output gear mounting member 9 and a sealing arrangement 12a, 12b configured to seal between the output gear mounting member and the housing such that a sealed enclosure 11 is provided externally of the output gear mounting member, within the housing. The gearbox has an installation configuration in which the housing has a sleeve insertion opening 14 for inserting an output drive sleeve 6 through, into an interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing. The output gear mounting member comprising a coupling arrangement 32 configured to couple the output gear mounting member to the output drive sleeve such that rotation of the output gear mounting member rotates the output drive sleeve.

Description

Field of the Invention The present invention relates to a gearbox for a valve. In particular, but not exclusively, the present invention relates to a gearbox for a valve for managing fluid flow in the oil, gas, water, chemical and power industries. In particular, but not exclusively, the present invention relates to a gearbox for a valve for transmitting rotation from an actuation device, for example a motor, to the valve, to operate the valve. The present invention also relates to a valve and gearbox assembly, a kit of parts of a gearbox for a valve, a valve gear installation system, an output drive sleeve for receiving a valve stem and coupling to the valve stem, a sleeve formation part, a method of assembly of a gearbox for a valve, a method of installation of a gearbox with a valve and a method of supplying a gearbox installation system for a valve. Background of the Invention It is desirable to be able to supply and / or install a gearbox for a valve in a sealed state, in which a sealed enclosure is provided in the housing, for example within which a gearing system of the gearbox is located, for example such that lubricating fluid in the sealed enclosure is prevented from leaving the sealed enclosure. However, due to different valves having different valve stems, with different coupling arrangements, as well as the need to rotationally position a drive sleeve in a particular rotational position relative to a valve stem, in order to be able to couple the sleeve to the valve stem, there are a number of design obstacles to being able to supply and / or install a gearbox for a valve in a sealed state. The present invention seeks to address or mitigate at least some of the above mentioned problems. Alternatively, or additionally, the present invention seeks to provide an improved gearbox for a valve. Alternatively, or additionally, the present invention seeks to provide an improved valve gear installation system. Alternatively, or additionally, the present invention seeks to provide an improved valve and gearbox assembly. Alternatively, or additionally, the present invention seeks to provide an improved kit of parts of a gearbox for a valve. Alternatively, or additionally, the present invention seeks to provide an output drive sleeve for coupling to a valve stem. Alternatively, or additionally, the present invention seeks to provide an improved sleeve formation part. Alternatively, or additionally, the present invention seeks to provide an improved method of installation of a gearbox with a valve. Alternatively, or additionally, the present invention seeks to provide an improved method of supplying a gearbox installation system for a valve. Summary of the Invention According to a first aspect of the invention there is provided a gearbox for a valve, the gearbox comprising: a housing; a gear arrangement comprising an input gear and an output gear, the output gear being arranged to be rotatably driven by the input gear; the output gear being connected to an output gear mounting member such that rotation of the output gear rotates the output gear mounting member; the gearbox comprising a sealing arrangement configured to seal between the output gear mounting member and the housing such that a sealed enclosure is provided externally of the output gear mounting member, within the housing; the housing having a valve stem insertion opening, for a valve stem to be inserted through; wherein: the gearbox is configurable to have, or is configured in, an installation configuration in which a sleeve insertion opening is provided in the housing for inserting an output drive sleeve through, into an interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing; and the output gear mounting member comprises a coupling arrangement configured to couple the output gear mounting member to a said output drive sleeve, that is so inserted into the interior of the output gear mounting member, such that rotation of the output gear mounting member rotates the output drive sleeve, and wherein the valve stem insertion opening is for a valve stem to pass through, into the output drive sleeve, such that the output drive sleeve is couplable to the valve stem such that rotation of the output drive sleeve rotates the valve stem. As the gearbox is configurable to have, or is configured in, an installation configuration in which a sleeve insertion opening is provided in the housing for inserting an output drive sleeve through, into an interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing, that provides a sealed enclosure externally of the output gear mounting member, within the housing, this may allow the gearbox to be delivered and installed in said sealed condition, where said sealed enclosure is provided in the housing. This may, for example, prevent lubricating fluid from leaking out of the sealed enclosure and / or fluid and / or detritus from entering the sealed enclosure, during delivery and installation, which may allow the gearbox to maintain its seal rating (e.g. IP68 rating) during delivery and installation. Alternatively, or additionally, it may allow the drive sleeve to be inserted into the output gear mounting member after the gearbox has been mounted onto a valve (e.g. attached to a valve flange). This may provide for ease of installation, since the drive sleeve can be rotated to a rotational position, relative to a valve stem, in which the valve stem is receivable by the drive sleeve to couple to the drive sleeve, before the drive sleeve is inserted into the interior of the output gear mounting member. This may remove the need to rotate the entire gearbox to rotate the drive sleeve to said correct rotational position relative to the valve stem. Furthermore, it may allow for drive sleeves with different coupling arrangements, for coupling to different valve stems, to be used with same gearbox. It also allows for a sleeve formation part, for having at least part of its interior removed such that the sleeve formation part forms an output drive sleeve tailored to a specific valve requirements, to be delivered and / or installed separately to the gearbox, with the gearbox being delivered and / or installed in said sealed condition. Optionally the coupling arrangement is configured such that the output gear mounting member is so couplable to a said output drive sleeve by the insertion of the output drive sleeve into the interior of the output gear mounting member. This may provide for ease of installation, as it may remove the need for any separate fasteners to be required to couple the output gear mounting member to the output drive sleeve. Optionally the output gear mounting member is rotatably mounted to the housing. Optionally the coupling arrangement comprises at least one formation that is for engaging with at least one formation of a said output drive sleeve by the insertion of the output drive sleeve into the interior of the output gear mounting member. Optionally the coupling arrangement is configured such that output gear mounting member is so couplable to the output drive sleeve in a plurality of rotational positions of the output drive sleeve relative to the output gear mounting member. This may provide for ease of installation, as it may allow the output drive sleeve to be rotated to a rotational position, relative to a valve stem, in which the valve stem is receivable by the drive sleeve to couple to the drive sleeve, before the drive sleeve is inserted into the interior of the output gear mounting member. This may remove the need to rotate the entire gearbox to rotate the drive sleeve to said correct rotational position relative to the valve stem. Optionally the coupling arrangement comprises a plurality of formations distributed circumferentially about an interior surface of the output gear mounting member, wherein the plurality of formations are for engaging with at least one formation of a said output drive sleeve in a plurality of rotational positions of the output drive sleeve relative to the output gear mounting member . Optionally the coupling arrangement is configured such that a said output drive sleeve may be selectively so coupled to and decoupled from the output gear mounting member. This may provide for ease of installation and removal of gearbox with and from a valve. Optionally the gearbox comprises a closure member that is movable relative to the housing between an open position, in which the sleeve insertion opening is provided, to configure the gearbox in the installation configuration, and a closed position in which the sleeve insertion opening is closed by the closure member . This may prevent the ingress of fluid or detritus from external the gearbox into the interior of the output gear mounting member and so may prevent the ingress of fluid or detritus from external the gearbox into the output drive sleeve and valve stem. Optionally the gearbox comprises a seal configured to provide a seal between the housing and the closure member, when the closure member is in said closed position. This may prevent the ingress of fluid or detritus from external the gearbox into the interior of the output gear mounting member and so may prevent the ingress of fluid or detritus from external the gearbox into the output drive sleeve and valve stem. Optionally the gearbox comprises an indicator that is configured to indicate at least one position of said valve and wherein the closure member comprises at least part of the indicator . The dual use of the indicator as a valve position indicator and the closure member may reduce the number of parts required, thereby saving on cost and space. Optionally the sealing arrangement comprises: a first seal configured to provide a seal between the output gear mounting member and the housing at a first location on the output gear mounting member; and a second seal configured to provide a seal between the output gear mounting member and the housing at a second location on the output gear mounting member; wherein the first and second locations are spaced apart along the output gear mounting member such that said sealed enclosure is provided between the first and second seals . Optionally: the first seal is configured to prevent fluid from passing from the exterior of the housing, via the sleeve insertion opening, into the sealed enclosure; and the second seal is configured to prevent fluid from passing from the exterior of the housing, via the valve stem insertion opening, into the sealed enclosure. Optionally: a first part of the output gear mounting member is arranged to rotate within the sleeve insertion opening; and a second part of the output gear mounting member is arranged to rotate within the valve stem insertion opening. Optionally the first seal provides a seal between the first part of the output gear mounting member and the housing and the second seal provides a seal between the second part of the output gear mounting member and the housing. Optionally: the housing has first and second parts; the first and second parts are selectively attachable to and detachable from each other and when the first part is detached from the second part, the first part is movable relative to the second part between a closed position and an open position; when the first part is in the open position, the output gear mounting member can be received in the housing and rotatably mounted to the housing such that rotation of the output gear rotates the output gear mounting member, and when the first part is in the closed position, with the first part attached to the second part, the sealing arrangement provides said seal between the output gear mounting member and the housing. This may provide for ease of assembly of the output gear mounting member in the housing. Optionally the gearbox comprises a housing sealing arrangement configured such that, when the first part is in the closed position and attached to the second part, a seal is provided between the first and second parts such that said sealed enclosure is provided externally of the output gear mounting member, within the housing. Optionally the output gear is provided in the sealed enclosure . Optionally the input gear is provided in the sealed enclosure . Optionally the gear arrangement is provided in the sealed enclosure . Optionally: the gearbox comprises an output drive sleeve for receiving a valve stem and coupling to the valve stem such that rotation of the output drive sleeve rotates the valve stem; wherein, when the gearbox is in the installation configuration, the output drive sleeve is insertable through the sleeve insertion opening into the interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing; and wherein the output drive sleeve comprises a coupling arrangement configured to couple the output drive sleeve to the coupling arrangement of the output gear mounting member, such that rotation of the output gear mounting member rotates the output drive sleeve; wherein the output drive sleeve is provided in the interior of the output gear mounting member and is so coupled to the output gear mounting member by said coupling arrangement. Optionally the coupling arrangement of the output drive sleeve and the coupling arrangement of the output gear mounting member are configured such that the output gear mounting member is so couplable to the output drive sleeve by the insertion of the output drive sleeve into the interior of the output gear mounting member. Optionally the coupling arrangement of the output drive sleeve comprises at least one formation that is for engaging with at least one formation of the coupling arrangement of the output gear mounting member by the insertion of the output drive sleeve into the interior of the output gear mounting member. Optionally the coupling arrangement of the output drive sleeve and the coupling arrangement of the output gear mounting member are configured to allow for said coupling of the output gear mounting member to the output drive sleeve in a plurality of rotational positions of the output drive sleeve relative to the output gear mounting member. Optionally the coupling arrangement of the output drive sleeve comprises a plurality of formations distributed circumferentially about an exterior surface of the output drive sleeve, wherein the plurality of formations are for engaging with the plurality of formations distributed circumferentially about the interior surface of the output gear mounting member in a plurality of rotational positions of the output drive sleeve relative to the output gear mounting member. Optionally the coupling arrangement of the output drive sleeve and the coupling arrangement of the output gear mounting member are configured such that the output drive sleeve may be selectively coupled to and decoupled from the output gear mounting member. Optionally the output drive sleeve comprises a coupling arrangement for coupling the output drive sleeve to a coupling arrangement of a valve stem such that rotation of the output drive sleeve rotates the valve stem. Optionally the gear arrangement comprises a worm drive. Optionally: the worm drive comprises a worm screw and a worm gear engaged with the worm screw; and wherein one of the input gear and the output gear comprises the worm screw and the other comprises the worm gear. Optionally the input gear comprises the worm screw and the output gear comprises the worm gear. Optionally the worm drive is a quarter turn worm drive and the worm gear is a worm gear quadrant. Optionally the gearbox comprises an input drive member and wherein the input gear is coupled to the input drive member such that the input drive member drives the input gear such that the output gear is rotated. According to a second aspect of the invention there is provided a gearbox and actuation device assembly comprising: a gearbox according to the first aspect of the invention; and an actuation device; wherein the actuation device is mechanically linked to the input drive member such that the actuator drives the input drive member to drive the input gear such that the output gear is rotated. Optionally the actuation device comprises an actuator and / or a manual actuation device. Optionally the input gear is configured to be rotatably driven and wherein the output gear is arranged to be rotatably driven by the rotation of the input gear. According to a third aspect of the invention there is 20 provided a valve and gearbox assembly comprising: a gearbox according to the first aspect of the invention, and a valve comprising a valve member and a valve stem that is coupled to the valve member such that rotation of the valve stem rotates the valve member to operate the valve; 30 the valve stem is received within the output drive sleeve and output drive sleeve is coupled to the valve stem such that rotation of the output drive sleeve rotates the valve stem, to operate the valve. According to a fourth aspect of the invention there is provided a kit of parts of a gearbox for a valve, the kit of parts comprising: a housing; a gear arrangement comprising an input gear and an output gear, the output gear being for being rotatably driven by the input gear; the output gear being connected to, or connectable to, an output gear mounting member such that rotation of the output gear rotates the output gear mounting member; the gearbox comprising a sealing arrangement for sealing between the output gear mounting member and the housing such that a sealed enclosure is provided externally of the output gear mounting member, within the housing; the housing having a valve stem insertion opening, for a valve stem to be inserted through; wherein: the gearbox is configurable to have, or is configured in, an installation configuration in which a sleeve insertion opening is provided in the housing for inserting an output drive sleeve through, into an interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing; and the output gear mounting member comprises a coupling arrangement configured to couple the output gear mounting member to a said output drive sleeve, that is so inserted into the interior of the output gear mounting member, such that rotation of the output gear mounting member rotates the output drive sleeve, and wherein the valve stem insertion opening is for a valve stem to pass through, into the output drive sleeve, such that the output drive sleeve is couplable to the valve stem such that rotation of the output drive sleeve rotates the valve stem. Optionally the kit of parts comprises: an output drive sleeve for receiving a valve stem and coupling to the valve stem such that rotation of the output drive sleeve rotates the valve stem; wherein, when the gearbox is in the installation configuration, the output drive sleeve is insertable through the sleeve insertion opening into the interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing; and wherein the output drive sleeve comprises a coupling arrangement configured to couple the output drive sleeve to the coupling arrangement of the output gear mounting member, such that rotation of the output gear mounting member rotates the output drive sleeve. According to a fifth aspect of the invention there is provided a kit of parts of a gearbox for a valve, the kit of parts comprising: a gearbox according to the first aspect of the invention; and a) an output drive sleeve for receiving a valve stem and coupling to the valve stem such that rotation of the output drive sleeve rotates the valve stem; wherein, when the gearbox is in the installation configuration, the output drive sleeve is insertable through the sleeve insertion opening into the interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing; and wherein the output drive sleeve comprises a coupling arrangement configured to couple the output drive sleeve to the coupling arrangement of the output gear mounting member, such that rotation of the output gear mounting member rotates the output drive sleeve; or b) a sleeve formation part for having at least part of its interior removed such that the sleeve formation part forms an output drive sleeve for receiving a valve stem and coupling to the valve stem such that rotation of the output drive sleeve rotates the valve stem; wherein, when the gearbox is in the installation configuration, the output drive sleeve is insertable through the sleeve insertion opening into the interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing; and wherein the output drive sleeve comprises a coupling arrangement configured to couple the output drive sleeve to the coupling arrangement of the output gear mounting member, such that rotation of the output gear mounting member rotates the output drive sleeve. According to a sixth aspect of the invention there is provided a valve gearbox installation system comprising: a gearbox according to the first aspect of the invention; and a) an output drive sleeve for receiving a valve stem and coupling to the valve stem such that rotation of the output drive sleeve rotates the valve stem; wherein, when the gearbox is in the installation configuration, the output drive sleeve is insertable through the sleeve insertion opening into the interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing; 5 and wherein the output drive sleeve comprises a coupling arrangement configured to couple the output drive sleeve to the coupling arrangement of the output gear mounting member, such that rotation of the output gear mounting member rotates the 10 output drive sleeve; or b) a sleeve formation part for having at least part of 15 its interior removed such that the sleeve formation part forms an output drive sleeve for receiving a valve stem and coupling to the valve stem such that rotation of the output drive sleeve rotates the valve stem; 20 wherein, when the gearbox is in the installation configuration, the output drive sleeve is insertable through the sleeve insertion opening into the interior of the output gear mounting 25 member, whilst said seal is provided between the output gear mounting member and the housing; and wherein the output drive sleeve comprises a coupling arrangement configured to couple the 30 output drive sleeve to the coupling arrangement of the output gear mounting member, such that rotation of the output gear mounting. According to a seventh aspect of the invention there is provided an output drive sleeve for receiving a valve stem and coupling to the valve stem such that rotation of the output drive sleeve rotates the valve stem; wherein the output drive sleeve comprises a coupling arrangement for coupling the output drive sleeve to a coupling arrangement of an output gear mounting member, such that rotation of the output gear mounting member rotates the output drive sleeve . According to an eight aspect of the invention there is provided a sleeve formation part for having at least part of its interior removed such that the sleeve formation part forms an output drive sleeve according to the seventh aspect of the invention. According to a ninth aspect of the invention there is provided a method of assembly of a gearbox for a valve, comprising: • providing a housing; • providing a gear arrangement comprising an input gear and an output gear, the output gear being arranged to be rotatably driven by the input gear, the output gear being connected to an output gear mounting member; • rotatably mounting the output gear mounting member to the housing such that rotation of the output gear rotates the output gear mounting member; wherein: the gearbox is configurable to have, or is configured in, an installation configuration in which a sleeve insertion opening is provided in the housing for inserting an output drive sleeve through, into an interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing; and the output gear mounting member comprises a coupling arrangement configured to couple the output gear mounting member to a said output drive sleeve, that is so inserted into the interior of the output gear mounting member, such that rotation of the output gear mounting member rotates the output drive sleeve, and wherein the valve stem insertion opening is for a valve stem to pass through, into the output drive sleeve, such that the output drive sleeve is couplable to the valve stem such that rotation of the output drive sleeve rotates the valve stem. Optionally: the housing has first and second parts; the first and second parts are selectively attachable to and detachable from each other and when the first part is detached from the second part, the first part is movable relative to the second part between a closed position and an open position; wherein: the output gear mounting member is rotatably mounted to the housing such that rotation of the output gear rotates the output gear mounting member, when the first part is in the open position. Optionally: after the output gear mounting member has been rotatably mounted to the housing, the first part is moved from the open position to the closed position and the first part attached to the second part, in the closed position; wherein when the first part is in the closed position, the sealing arrangement provides said seal between the output gear mounting member and the housing. Optionally the method comprises: • providing an output drive sleeve; • configuring the gearbox in an installation configuration in which a sleeve insertion opening is provided in the housing; • inserting the output drive sleeve through the sleeve insertion opening, into an interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing; coupling the output gear mounting member to the output drive sleeve such that rotation of the output gear mounting member rotates the output drive sleeve. According to a tenth aspect of the invention there is provided a method of installation of a gearbox with a valve, the method comprising: providing an output drive sleeve; providing a gearbox for a valve, the gearbox comprising: a housing; a gear arrangement comprising an input gear and an output gear, the output gear being arranged to be rotatably driven by the input gear; the output gear being connected to an output gear mounting member such that rotation of the output gear rotates the output gear mounting member; the gearbox comprising a sealing arrangement configured to seal between the output gear mounting member and the housing such that a sealed enclosure is provided externally of the output gear mounting member, within the housing; the housing having a valve stem insertion opening, for a valve stem to be inserted through; wherein the method further comprises: • configuring the gearbox in an installation configuration in which a sleeve insertion opening is provided in the housing; • inserting a valve stem through the valve stem insertion opening into the interior of the output gear mounting member; • inserting the output drive sleeve through the sleeve insertion opening, into an interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing; • coupling the output gear mounting member to the output drive sleeve such that rotation of the output gear mounting member rotates the output drive sleeve; • receiving the valve stem in the output drive sleeve to couple the output drive sleeve to the valve stem such that rotation of the output drive sleeve rotates the valve stem. Optionally the output drive sleeve is coupled to the output gear mounting member in a rotational position relative to the valve stem such that the valve stem can be received by the output drive sleeve and coupled to the output drive sleeve in said relative rotational position. Optionally the valve stem is inserted through the valve stem insertion opening before the output drive sleeve is coupled to the output gear mounting member. Alternatively, the valve stem may be inserted through the valve stem insertion opening after the output drive sleeve is coupled to the output gear mounting member. According to an eleventh aspect of the invention there is provided a method of supplying a gearbox installation system for a valve, the method comprising: supplying a gearbox; supplying an output drive sleeve or a sleeve formation part for having at least part of its interior removed such that the sleeve formation part forms an output drive sleeve; wherein the gearbox comprises: a housing; a gear arrangement comprising an input gear and an output gear, the output gear being arranged to be rotatably driven by the input gear; the output gear being connected to an output gear mounting member such that rotation of the output gear rotates the output gear mounting member; the gearbox comprising a sealing arrangement configured to seal between the output gear mounting member and the housing such that a sealed enclosure is provided externally of the output gear mounting member, within the housing; the housing having a valve stem insertion opening, for a valve stem to be inserted through; wherein: the gearbox is configurable to have, or is configured in, an installation configuration in which a sleeve insertion opening is provided in the housing for inserting the output drive sleeve through, into an interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing; and the output gear mounting member comprises a coupling arrangement configured to couple the output gear mounting member to the output drive sleeve, that is so inserted into the interior of the output gear mounting member, such that rotation of the output gear mounting member rotates the output drive sleeve, and wherein the valve stem insertion opening is for a valve stem to pass through, into the output drive sleeve, such that the output drive sleeve is couplable to the valve stem such that rotation of the output drive sleeve rotates the valve stem. Optionally the method comprises: removing at least part of the interior of a sleeve formation part such that the sleeve formation part forms an output drive sleeve comprising a coupling arrangement for coupling the output drive sleeve to a coupling arrangement of a valve stem such that rotation of the output drive sleeve rotates the valve stem. Optionally the coupling arrangement of the output drive sleeve is configured to couple to a specific valve stem. According to a further aspect of the invention there is provided an apparatus comprising a gearbox for a valve and a rotational drive transmitting device, the apparatus comprising: a gearbox comprising: a housing, and a gearing arrangement provided in the housing; the gearing arrangement comprising an input gear and an output gear mechanically linked to the input gear such that rotation of the input gear acts to rotate the output gear, and wherein the output gear is for being mechanically linked to a valve stem such that rotation of the output gear acts to rotate the valve stem, to operate a valve comprising the valve stem; the apparatus further comprising: a rotational drive transmitting device comprising: a housing; a rotational drive transmitting arrangement provided, at least partially, in the rotational drive transmitting device housing, the rotational drive transmitting arrangement being mechanically linked to the input gear of the gearbox such that, when the rotational drive transmitting arrangement is rotatably driven, the input gear is rotatably driven, via the rotational drive transmitting arrangement; the rotational drive transmitting arrangement comprising an output rotational drive member mechanically linked to the input gear of the gearbox such that rotation of the output rotational drive member, about a rotational axis, rotates the input gear of the gearbox; wherein the gearbox housing and the rotational drive transmitting device housing each comprise a respective attachment part, the attachment parts being attached to each other, to attach the gearbox housing and the rotational drive transmitting device housing to each other; wherein one of the attachment parts comprises a male part and other comprises a female part that receives the male part; and wherein the male and female parts are configured such that, when the input gear of the gearbox is rotatably driven, via the rotational drive transmitting arrangement, in at least one rotational direction, at least one outer peripheral surface of the male part contacts at least one inner peripheral surface of the female part to react at least part of a torque exerted on the male and / or female parts that acts to try to cause relative rotation of the male and female parts about said rotational axis of the output rotational drive member. It will be appreciated that said torque exerted on the male and / or female parts that acts to try to cause relative rotation of the male and female parts about said rotational axis is due to applied torque from a driving rotation that rotates the input gear of the gearbox, via the rotational drive transmitting arrangement. Optionally the gearbox housing comprises said female attachment part and the rotational drive transmitting housing comprises said male attachment part. Optionally the contacting surfaces of the male and female parts are configured such that the contacting surfaces act to prevent relative rotation of the male and female parts about the rotational axis of the output rotational drive member, in at least one rotational direction about the rotational axis. Optionally the male and female parts interlock such that said torque reaction is provided. Optionally the male and female parts interlock such that the interlocking of the male and female parts acts to prevent relative rotation of the male and female parts about the rotational axis of the output rotational drive member, in at least one rotational direction about the rotational axis. Optionally: the male and female parts each have a periphery that extends around the rotational axis of the output rotational drive member; and wherein the contacting surfaces of the male and female parts are each at least one surface of said periphery of the male and female parts respectively. In respect of each of the male and female parts, optionally said at least one outer peripheral contacting surface is a plurality of outer peripheral contacting surfaces. Optionally the outer peripheral contacting surfaces extend entirely around the rotational axis. Optionally the outer peripheral contacting surfaces extend circumscribe the rotational axis. Optionally the contacting surfaces of the male and female parts are substantially planar. Optionally the periphery of each of the male and female parts is a quadrilateral shape. Optionally the periphery of each of the male and female parts is a square shape. Optionally the at least one contacting surface of the female part is oriented such that, at at least one point along its surface, the normal to the surface extends in a direction that has a least a component in the opposite direction to the local direction of the torque exerted on the male and / or female parts that acts to try to cause relative rotation of the male and female parts about said rotational axis of the output rotational drive member. Optionally the contacting surfaces of the male and female parts are configured such that they produce a reaction force in a direction that has a least a component in the opposite direction to the local direction of the torque exerted on the male and / or female parts that acts to try to cause relative rotation of the male and female parts about said rotational axis of the output rotational drive member. Optionally the output rotational drive member passes through the attachment parts. Optionally the output rotational drive member passes through the centre of the attachment parts. Optionally said at least one rotational direction is both rotational directions. Optionally: the male and female parts are attached to each other by at least one fastener; and wherein said contact between the contacting surfaces of the male and female parts at least partially reduces the force that would have otherwise been exerted on the at least one fastener due to the torque exerted on the male and / or female parts that acts to try to cause relative rotation of the male and female parts about said rotational axis of the output rotational drive member . Optionally the gearbox comprises an input rotational drive member mechanically linked to the input gear such that rotation of the input rotational drive member acts to rotate the input gear. Optionally the input rotational drive member is rotatably drivable in first and second opposite rotational directions to rotate the output gear in first and second opposite rotational directions respectively. Optionally the input rotational drive member is rotatably drivable from first and second ends of the rotational drive member . Optionally: the attachment part of the gearbox housing is a first attachment part and the gearbox housing comprises a second said attachment part, for said attachment to the attachment part of the rotational drive transmitting device housing. Optionally when the input gear is rotatably driven, via the rotational drive transmitting arrangement, torque exerted on the male and / or female parts is exerted by the rotational drive transmission arrangement. Optionally: the rotational drive transmitting arrangement comprises a gearing arrangement configured such that the rotational drive transmitting housing is caused to try and rotate, about said rotational axis, when the input gear is rotatably driven, via the rotational drive transmitting arrangement; and / or the rotational drive transmitting device is connectable to an actuation device such that a rotational torque applied by the actuation device, to drive the input gear via the rotational drive transmitting device, causes the rotational drive transmitting housing to try and rotate, about said rotational axis . Optionally the apparatus comprises an actuation device mechanically linked to the input gear of the gearbox, via the rotational drive transmitting device, such that the input gear is rotatably drivable by the actuation device, via the rotational drive transmitting device. Optionally the actuation device comprises a housing that is attached to the rotational drive transmitting device housing such that the rotational drive transmitting device housing is rotationally fixed relative to the actuation device housing. The features of any of the above aspects of the invention may be combined with one or more features of any of the other aspects of the invention, in any combination. The steps in any of the above methods may be carried out in any order and are not limited to the order presented. Other preferred and advantageous features of the invention will be apparent from the following description. Description of the Drawings A specific embodiment of the invention will now be described with reference to the description and drawings. Figure 1 shows an exploded perspective view, from a first side, of an apparatus comprising a gearbox for a valve and a rotational drive transmitting device according to an aspect of the present invention and a valve, where part of the valve is cut-away for illustrative purposes and where an actuator mechanically linked to a gearing arrangement of gearbox, via the rotational drive transmitting device, is shown schematically (in dotted outline); Figure 2 shows a view corresponding to that of Figure 1, but from a second side; Figure 3 shows a view but in a non-exploded view configuration; corresponding to that of Figure 1, and where the gearbox is in a use Figure 4 shows an enlarged view of the region labelled 'A' in Figure 3; Figure 5 shows a schematic view illustrating a torque reaction of male and female parts of attachment parts of a rotational drive transmitting device housing and the gearbox housing respectively; Figure 6 shows a cross-sectional view of the gearbox, taken along a central plane, where the gearbox is in a use configuration; Figure 7 shows a rear perspective view of the apparatus of Figure 1, with the gearbox installed on a valve and connected to an actuation device, where the gearbox is in a use configuration; Figure 8 shows a view corresponding to that of Figure 7, but where the gearbox is in an installation configuration; Figure 9 shows a view corresponding to that of Figure 4, but of a second embodiment of the apparatus; Figure 10 illustrates the machining of the interior of a sleeve formation part to form an output drive sleeve of the apparatus, and Figure 11 schematically shows the steps in a method of supplying a gearbox installation system for a valve. Detailed Description Referring to Figure 1, there is shown an exploded perspective view, from a first side, of an apparatus 701 comprising a gearbox 1 for a valve 2 and a rotational drive transmitting device 700 according to an aspect of the present invention and a valve 2, where part of the valve 2 is cut-away for illustrative purposes and where an actuation device 41 mechanically linked to a gearing arrangement 4 of gearbox 1, via the rotational drive transmitting device 700, is shown schematically (in dotted outline). In the described embodiment, the valve 2 is of the type for managing fluid flow in the oil, gas, water, chemical or power industries, for example. The gearbox 1 comprises an input rotational drive member 5, in the form of an input drive shaft 5, an output drive sleeve 6, a housing 3 and a gear arrangement 4 for mechanically linking (together with the splines 32 on the output gear mounting member 9) the input drive shaft 5 to the output drive sleeve 6 such that, in use, when the output drive sleeve 6 is coupled to a valve stem 7 (described further below), rotation of the input rotational drive member 5 drives rotation of the output drive sleeve 6, to rotate the valve stem 7 to operate the valve 2. In the currently described embodiment, the housing 3 and output gear mounting member 9 are made of iron. However, it will be appreciated that any suitable material may be used. In the currently described embodiment, the output drive sleeve 6 is made of steel. However, it will be appreciated that any suitable material may be used. The housing 3 comprises a first part 3a, in the form of a lid 3a and a second part 3b, in the form of a main body 3b. The housing lid 3a is selectively attachable to and detachable from an upper peripheral side 18 of the main body 3b by a plurality of fasteners 10, in the form of screws 10, distributed about the periphery of the lid 3a and passing through the lid 3a into openings 17 in an upper peripheral side 18 of the main body 3b (see Fig. 2). A sleeve insertion opening 14, in the form of circular opening 14 is provided in the housing lid 3a (when the gearbox 1 is in an installation configuration, described below), that extends throughout the thickness of the housing lid 3a, from an outer surface 23 of the lid 3a (which in the orientation shown is an upper surface) to an inner surface 24 of the lid 3a (which in the orientation shown is a lower surface) . The circular opening 14 is centred on the rotational axis B of the output gear mounting member 9 (see below). The lid 3a also comprises a circular rim 23' that circumscribes the sleeve insertion opening 14 and extends outwardly (which is upwardly in the orientation shown) from the outer surface 23 of the lid 3a. The sleeve insertion opening 14 is in communication with the interior of the output gear mounting member 9 such that the sleeve 6 can be inserted through the opening 14 into the interior of the output gear mounting member 9 (described below). A valve stem insertion opening 15, in the form of a circular opening 15, is provided in a base 16 of the main body 3b of the housing 3. The opening 15 extends throughout the thickness of the base 16, from an outer surface 25 of the base 16 (which in the orientation shown is a lower surface) to an inner surface 26 of the base 16 (which in the orientation shown is an upper surface). The opening 15 is centred on the rotational axis B of the output gear mounting member 9 (see below). The input drive shaft 5 is provided within the main body 3b of the housing 3 and is rotatably mounted to the main body 3b so as to rotate about a rotational axis C. The input drive shaft 5 is mechanically linked to an output drive shaft 40 of an actuator 170 (shown schematically in Figure 7) of an actuation device 41 by a step down transmission 42, in the form of a planetary gear transmission 42. The gear arrangement 4 is a quarter turn worm drive comprising an input gear 30, in the form of a worm screw 30 and an output gear 8, in the form of a worm gear quadrant 8. The worm screw 30 is mounted to the input drive shaft 5, which passes through the worm screw 30 and is rotationally fixed to the worm screw 30, such that rotation of the input drive shaft 5 rotates the worm screw 30 about the rotational axis C. The worm screw 30 is engaged with the worm gear quadrant 8 by intermeshing of a screw 30' of the worm screw 30 with teeth 8' of the worm gear quadrant 8. The output gear 8 is mounted to an output gear mounting member 9. The output gear mounting member 9 is a hollow, generally cylindrical hollow member that extends between first and second ends 9a, 9b (which in the orientation shown in Figures 1 to 4 are upper and lower ends 9a, 9b respectively) along a central longitudinal axis B, that the output gear mounting member 9 rotates about (see below). The output gear mounting member 9 is rotatably mounted to the housing 3 so as to rotate relative to the housing 3 about said axis B. In this respect, the upper and lower ends 9a, 9b of the output gear mounting member 9 are respectively rotatably mounted in the sleeve insertion opening 14 in the housing lid 3a and in the valve stem insertion opening 15 in the base 16 of the main body 3b of the housing 3, so as to rotate about said axis B. A middle part 9c of the output gear mounting member 9 extends between the upper and lower ends 9a, 9b. The diameter of the middle part 9c of the output gear mounting member 9 is greater than the diameters of the sleeve insertion opening 14 and the valve stem insertion opening 15. The worm gear quadrant 8 is mounted to the output gear mounting member 9 such that rotation of the worm screw 30 rotates the worm gear quadrant 8 and output gear mounting member 9 about the rotational axis B. The gearbox 1 further comprises a sealing arrangement configured to seal between the output gear mounting member 9 and the housing 3 such that a sealed enclosure 11 (see Figure 6) is provided externally of the output gear mounting member 9, within the housing 3. The gearing arrangement 4, namely the worm screw 30 and worm gear quadrant 8, is located within the sealed enclosure 11. The sealing arrangement comprises upper and lower seals in the form of upper and lower O-rings 12a, 12b. The upper and lower seals each extend around the circumference of the upper and lower parts of the output gear mounting member 9 respectively. The upper and lower seals 12a, 12b are dynamic seals. The upper and lower ends 9a, 9b of the output gear mounting member 9 are of a lower diameter than the middle part 9c. Upper and lower lips 20, 21 of the mounting member 9 are provided at the transition between the main part 9c and the upper and lower ends 9a, 9b respectively. The upper O-ring 12a is mounted in a circular recess 60 in the rim 23' of the housing lid 3a and circumscribes the sleeve insertion opening 14. The upper O-ring 12a contacts and seals between opposed surfaces of the upper end 9a of the output gear mounting member 9 and the housing 3. The lower O-ring 12b is mounted in a circular recess 61 in the base 16 of housing main body 3b and circumscribes the valve stem insertion opening 15. The lower O-ring 12b contacts and seals between opposed surfaces of the lower end 9b of the output gear mounting member 9 and the housing 3. A housing seal 13 is mounted on the upper peripheral side 18 of the main body 3b and is a continuous seal that extends along the length of the upper peripheral side 18 and contacts and seals between opposed surfaces of the upper peripheral side 18 of the main body 3b and the lower surface 24 of the housing lid 3a. The housing seal 13 is a static seal. The housing 3 is configurable between an open configuration and a closed configuration. In this respect, when the lid 3a is detached from the main body 3b and moved relative to the main body 3b, to a position in which the output gear mounting member 9 can be received in the housing 3 (illustrated by the exploded view in Figure 1), and the lower end 9b of the output gear mounting member 9 mounted in the valve stem insertion opening 15, the housing 3 is in an open configuration. When the lid 3a is attached to the main body 3b (by the fasteners 10) , as shown in Figure 3, with the upper end 9a of the output gear mounting member 9 mounted in the sleeve insertion opening 14 and the lower end 9b of the output gear mounting member 9 mounted in the valve stem insertion opening 15, with said sealing provided by the upper and lower O-rings 12a, 12b and by the housing seal 13, the housing 3 is in a closed configuration. Accordingly, during assembly of the gearbox 1, the housing 3 can be configured into the open configuration, by said detachment and positioning of the housing lid 3a relative to the base 16. The output gear mounting member 9 may then be received within the housing 3, with the lower end 9b of the output gear mounting member 9 mounted in the valve stem insertion opening 15. When the housing 2 is in the open configuration, the input drive shaft 5 can be inserted through a central opening 63 in the side of the housing 3, through the worm screw 30 and into a mounting bore 64 in the other side of the main body 3b of the housing 3 so as to rotationally mount the input drive shaft 5 to the housing 3, to rotate about the rotational axis C. The input drive shaft 5 and worm screw 30 may be inserted into the main body 3b of the housing before, after or the same time as the output gear mounting member 9. The housing 3 is then configured into the closed configuration, by the attachment of the housing lid 3a to the main body 3b of the housing 3, with the upper end 9a of the output gear mounting member 9 mounted in the opening 14, in the housing lid 3a. When the housing 3 is in the closed configuration, the upper and lower ring seals 12a, 12b and the housing seal 13 form a sealing arrangement that provides a sealed enclosure 11 within the housing 3, external to the output gear mounting member 9, with the gear arrangement 4, namely the worm gear quadrant 8 (output gear) and the worm screw 30 (input gear) located within the sealed enclosure 11. A lubricant is provided in the sealed enclosure 11, to lubricate the gearing arrangement 4. In the currently described embodiment the lubricant is grease. However, it will be appreciated that any suitable lubricant may be used. The seals 12a, 12b, 13, are for substantially preventing the lubricant from leaking out of the sealed enclosure 11. The lubricant is not pressurised. In this respect, the seals 12a, 12b, 13 create a substantially liquid tight enclosure. The seals 12a, 12b, 13 also prevent the ingress of external fluid and detritus (under normal atmospheric pressures) from entering the sealed enclosure 11 from external to the housing 3. Any suitable material and type of seal may be used, for example Viton (RTM), nitrile rubber, fluorosilicone seals, etc. The output drive sleeve 6 is a generally cylindrical hollow member that extends between first and second ends 6a, 6b (which in the orientation shown in Figures 1 to 4 are upper and lower ends 6a, 6b respectively) along a central longitudinal axis B' that, when the output drive sleeve 6 is coupled to the output gear mounting member 9, is co-axial with the rotational axis B. A section of the output drive sleeve 6, at the first end of the sleeve 6, is provided with a coupling arrangement 31 in the form of a plurality of male splines 31 distributed circumferentially about the exterior of the sleeve 6. In this respect, each spline extends longitudinally, from the first end 6a of the sleeve 6, towards the second end 6b of the sleeve 6, along a longitudinal axis that is parallel to the rotational axis B. The splines 31 are in a continuous side by side arrangement. In this respect, each spline extends from an adjacent spline on one side to an adjacent spline on the other side . The output gear mounting member 9 is provided with a coupling arrangement 32 in the form of a plurality of female splines 32 distributed circumferentially about the interior of the output gear mounting member 9. In this respect, each spline extends longitudinally, from the first end 9a of the mounting member 9, towards the second end 9b of the mounting member 9, along a longitudinal axis that is parallel to the rotational axis B. The splines 32 are in a continuous side by side arrangement. In this respect, each spline extends from an adjacent spline on one side to an adjacent spline on the other side . The above coupling arrangement provides for a large degree of rotational positions in which the output drive sleeve 6 can be coupled to the output gear mounting member 9. The male splines 31 of the output drive sleeve 6 mesh with the female splines 32 of the output gear mounting member 9 such that the rotation of the output gear mounting member 9 rotates the output drive sleeve 6. The output drive sleeve 6 comprises a stem coupling arrangement 33, in the form of an elongate slot 33 that extends from the first end 6a of the sleeve 6 to the second end 6b of the sleeve 6. The slot 33 has a generally rectangular cross-sectional shape and extends along a longitudinal axis that is parallel to the longitudinal axis B' of the sleeve 6. It will be appreciated that any type of stem coupling arrangement may be used. The valve 2 comprises a valve member 50, in the form of a ball valve member 50 provided with an opening 51 that passes through the ball valve member 50. The ball valve member 50 is rotatably mounted in a fluid conduit 52, to rotate about a rotational axis B'' and is connected to a valve stem 7 such that rotation of the valve stem 7 about said axis B' ’ rotates the ball valve member 50 between an open position, in which the opening 51 is co-axial with the longitudinal axis of the conduit 52, such that fluid can flow through the valve member 50, a first closed position in which valve member 50 is rotated clockwise such that the axis of the opening 51 is perpendicular to the longitudinal axis of the conduit 52, such that fluid cannot flow through the valve member 50 and a second closed position in which valve member 50 is rotated anti-clockwise such that the axis of the opening 51 is perpendicular to the longitudinal axis of the conduit 52, such that fluid cannot flow through the valve member 50 . In this respect, the input rotational drive shaft 5 can be driven in both rotational directions about the rotational axis C, to rotate the valve member 50 in different directions, between its open position and its closed positions. The valve stem 7 comprises a sleeve coupling arrangement 54, in the form of an elongate protrusion 54 that extends along a middle section of the length of the stem 7 along a longitudinal axis that is parallel to the rotational axis of the valve stem 7 . The protrusion 54 has a generally rectangular cross-sectional shape, protrudes radially outwardly of the outer surface of the stem 7 and extends along a longitudinal axis that is parallel to the longitudinal axis B' of the sleeve 6. The elongate slot 33 in the output drive sleeve 6 is sized and dimensioned to receive the elongate protrusion 54 when the valve stem 7 is received within the output drive sleeve 6. When the protrusion 54 is located in the slot 33, the output drive sleeve 6 is coupled to the valve stem 7 such that as the output drive sleeve 6 rotates about the rotational axis B, the stem 7 is rotated about the rotational axis B, to rotate the ball valve member 50 between its open and closed positions. The gearbox 1 further comprises a circular indicator plate 80. The indicator plate 80 is selectively attachable to and detachable from the output gear mounting member 9. In this respect, the indicator plate 80 is attached to an upper peripheral edge 70 of the output gear mounting member 9 by a plurality of fasteners 51 that pass through openings 51' in the indicator plate 80 and into aligned openings 89 in the upper peripheral edge 70 of the output gear mounting member 9. Accordingly, as the output gear mounting member 9 rotates, about the rotational axis B, the indicator plate 80 also rotates, about the rotational axis B. The indicator plate 80 has markings 71, 72, 72' that align with a marking 73 on the housing lid 3a when the valve member 50 is in the open, first closed and second closed positions respectively. The indicator plate 80 forms a closure member. In this respect, when the indicator plate 80 is attached to the output gear mounting member 9, the indicator plate 80 closes the sleeve insertion opening 14. In this configuration, the gearbox is a 5 'use configuration'. An O-ring 90 provides a seal between an undersurface of the indicator plate 80 and an upper peripheral edge 81 of the rim 23'. The O-ring 90 is a dynamic seal. When the indicator plate 80 is not attached to the output 10 mounting member 9, and is removed such that the sleeve insertion opening 14 is open, the gearbox 1 is an installation configuration, in which the output drive sleeve 6 is insertable through the opening 14, into the interior of the output gear mounting member 9, whilst the upper and lower O-rings 12, 12b 15 provide said seal between the output gear mounting member 9 and the housing 3 and whilst the housing seal 13 provides said seal between the housing lid 3a and the housing main body 3b such that the sealed enclosure 11 is provided externally of the output gear mounting member 9, within the housing 3. 20 As the output drive sleeve 6 is inserted into the interior of the output gear mounting member 9, the output gear mounting member 9 and is coupled to the output drive sleeve 6 by the meshing of the male and female splines 31, 32 of the sleeve 6 and mounting member 9 respectively, during said insertion, such 25 that rotation of the output mounting member 9 rotates the output drive sleeve 6, to rotate the valve stem 7 to operate the valve 2 . The output drive sleeve 6 may be selectively coupled to and decoupled from the output gear mounting member 9 by the 30 engagement and disengagement of the splines 31, 32. In this respect, the sleeve 6 may be slid back out of the sleeve insertion opening 14 to disengage the 31, 32. The valve stem insertion opening 15 is for the valve stem 7 to pass through, into the output drive sleeve 6, when the gearbox 1 is mounted on the valve flange 98, such that the output drive sleeve 6 is coupled to the valve stem 7, by the receipt of the protrusion 54 on the valve stem 7 into the slot 33 in the output drive sleeve 6, such that rotation of the output drive sleeve 6 rotates the valve stem 7. As the gearbox 1 is configurable to have said installation configuration, in which the sleeve insertion opening 14 is provided in the housing 3 for inserting the output drive sleeve 6 through, into an interior of the output gear mounting member 9, whilst said seal is provided between the output gear mounting member and the housing 3, that provides a sealed enclosure 11 externally of the output gear mounting member 9, within the housing 3, this may allow the gearbox 1 to be delivered and installed in said sealed condition. This may, for example, prevent fluid and / or detritus from entering or leaving the sealed enclosure 11 (e.g. to prevent lubricating fluid leaking out of the sealed enclosure 11), during delivery and installation, which may allow the gearbox to maintain its seal rating (e.g. IP68 rating) during delivery and installation. Also, it allows the drive sleeve 6 to be inserted into the output gear mounting member 9 after the gearbox 1 has been mounted onto a valve 2 (e.g. mounted to valve flange 98). This may provide for ease of installation, since the drive sleeve 6 can be rotated to a rotational position, relative to the valve stem 7, in which the valve stem 7 is receivable by the drive sleeve to couple to the drive sleeve 6, before the drive sleeve 6 is inserted into the interior of the output gear mounting member 9. This removes the need to rotate the entire gearbox 1 to rotate the drive sleeve 6 to said correct rotational position relative to the valve stem 7. Furthermore, it allows for drive sleeves with different coupling arrangements, for coupling to different valve stems, to be used with same gearbox, i.e. with the same output gear mounting member 9. It also allows for a sleeve formation part 6' (see Figure 10), for having at least part of its interior removed such that the sleeve formation part 6' forms a said output drive sleeve 6 tailored to a specific valve requirements, to be delivered and / or installed separately to the gearbox 1, with the gearbox 1 being delivered and / or installed in said sealed condition. A method of assembly of the gearbox 1, according to a further aspect of the invention, comprises: • providing the housing 3; • configuring the housing 3 in the open configuration; • providing the gear arrangement 4 comprising the input gear 30 and the output gear 8, the output gear 8 being arranged to be rotatably driven by the input gear 30, the output gear 30 being connected to the output gear mounting member 9; • rotatably mounting the output gear mounting member 9 to the housing such that rotation of the output gear rotates the output gear mounting member 9, and • configuring the housing 3 in the closed configuration. A method of installation of the gearbox 1 with the valve, according to a further aspect of the invention, comprises: 5 • configuring the gearbox 1 in the installation configuration in which the sleeve insertion 14 opening is provided in the housing; • mounting the gearbox 1 onto the valve flange 98, such 10 that the valve stem 7 passes through the valve stem insertion opening 15 into the interior of the output gear mounting member 9; • inserting the output drive sleeve 6 through the sleeve 15 insertion opening 14, into an interior of the output gear mounting member 9, whilst said sealed enclosure 11 is provided by the seal provided between the 0-rings 12a, 12b and the housing 2 and between the housing seal 13 and the housing 3; 20 • coupling the output gear mounting member 9 to the output drive sleeve 6, by intermeshing said splines 31, 32 such that rotation of the output gear mounting 25 member 9 rotates the output drive sleeve 6; • receiving the valve stem 7 in the output drive sleeve 6 to couple the output drive sleeve 6 to the valve stem 7 such that rotation of the output drive sleeve 6 rotates the valve stem 7. The gearbox 1 may be configured in the installation configuration before or after the gearbox 1 is mounted onto the valve flange 98, but preferably before as this provides for ease of installation. With reference to Figures 10 and 11, a method of supplying a gearbox installation system for a valve, according to a further aspect of the invention comprises: • supplying the gearbox 1, without the output drive sleeve 6 (step 101); • supplying the output drive sleeve 6 or a sleeve formation part 6' for having at least part of its interior removed such that the sleeve formation part forms the output drive sleeve 6 (step 102) . Where the sleeve formation part 6' is supplied, the method may comprise removing at least part of the interior of the sleeve formation part 6' such that the sleeve formation part 6' forms the output drive sleeve 6 (step 103). As stated above, the input drive shaft 5 of the gearbox 1 is coupled to an output drive shaft 40 of the actuator 170 by a step-down transmission 42, in the form of a planetary gear transmission 42. The planetary gear transmission 42 is provided in a planetary gear transmission housing 203. The planetary gear transmission 42 comprises a sun gear 200 configured to rotate about said rotational axis C, and a plurality of planet gears 201 that mesh with the sun gear 200. The sun gear 200 is coupled to the output shaft 40 of the actuator 170 by a shaft 43 that is coupled to the shaft 40, by coupling arrangement in the form of a protrusion and slot (not shown), such that the shaft 43 rotates with shaft 40, to rotate the sun gear 200 about the rotational axis C. When the sun gear 200 is rotatably driven by the actuator 170, about the rotational axis C, the planet gears 201 rotate about their own local rotational axes, which are parallel to the rotational axis C. The teeth 201' of the planet gears 201 mesh with teeth 203' on the interior of the planetary gear transmission housing 203, which form an annulus of the planetary gear transmission. This causes the planet gears 201 to orbit around the sun gear 200 (and therefore around the rotational axis C). The planet gears 201 are each mounted, at one end, to a circular disc 202, which is attached to an end of the input rotational drive shaft 5 of the gearbox 1, by a connecting shaft 210 that rotates with the disc 202 about the rotational axis C and passes through a central circular opening 63 in a female attachment part 3b' of the gearbox housing 3 (see below) to connect to the input drive shaft 5. The orbit of the planet gears 201, about the rotational axis C, rotates the disc 202, which rotates the shaft 210, which rotates the input rotational drive shaft 5 of the gearbox 1 about the rotational axis C. The planet gears 201, disc 202 and connecting shaft 201 form an output rotational drive member of the transmission 42. In this respect, the planetary gear transmission 42 is a rotational drive transmitting arrangement 42 and the housing 203 is a rotational drive transmitting device housing 203. The housing 203 and rotational drive transmitting arrangement 42 together form a rotational drive transmitting device 700. The rotational drive transmitting device and the gearbox 1 form an apparatus 701. The gearbox housing 3 and the rotational drive transmitting device housing 203 each comprise a respective attachment part 3b', 203a. The attachment parts 3b', 203a are attached to each other, to attach the gearbox housing 3 and the rotational drive transmitting device housing 203 to each other. The attachment part 203a of the rotational drive transmitting device housing 203 is an end of the housing 203 that has a square shape that is centred on the rotational axis C and extends around the rotational axis C, to circumscribe the rotational axis C. An outer peripheral edge of the attachment part 203 extends around the rotational axis C, to define said square shape, and comprises oppositely facing planar upper and lower outer peripheral surfaces 203ai, 203az and oppositely facing planar side surfaces 203as, 203a4 (see Figure 4). The attachment part 3b' of the gearbox housing 3 is a part of the housing 3 that defines a square recess 204 that is centred on the rotational axis C. An inner peripheral edge of the attachment part 3b', that defines the square recess 204, extends around the rotational axis C, to circumscribe the rotational axis C, to define said square recess 204, and comprises opposed planar upper and lower inner peripheral surfaces 3bi, 3b2 and opposed planar side inner peripheral surfaces 3ba, 3b4 (see Figure 1) - The square attachment part 203a of the rotational drive transmitting device housing 203 is received in the square recess 204 (see Figure 3) in the attachment part 3b' of the gearbox housing 3, as shown in Figure 4. In this respect, the attachment part 203a of the rotational drive transmitting device housing 203 forms a male part 203a and the attachment part 3b' of the gearbox housing 3 forms a female part 3b' that receives the male part 203a. A plurality of fasteners 205, more specifically four fasteners 205, with a respective fastener 205 received in each corner of the attachment parts 3a, 203a, attach the attachment parts 3a, 203a to each other. The actuator 170, of actuation device 41, is an electric motor 170, that produces said rotational driving force. The actuator 170 is provided in an actuator housing 206 (see Figure 7). The actuator housing 206 is mounted to an opposite end of the transmission housing 203 (to the male part 203a) by a plurality of fasteners, in the form of four bolts 207, which are each mounted in a respective aperture 208 in a corner flange 208' of a mounting bracket 209 provided at said end of the transmission housing 203. This attachment is such that the transmission housing 203 is rotationally fixed relative to the actuator housing 206. When the gearing arrangement of the gearbox 1 is rotatably driven by the actuator 170, via the transmission 42, the applied torque from the actuator 170 and the rotation of the planet gears 201 within the annulus produces a torque on the transmission housing 203 that acts to try and rotate the male part 203a relative to the female part 3b' , in an opposite rotational direction to that of the applied rotation, about the rotational axis C. The outer peripheral surfaces 203ai, 203a2, 203a3, 203a4 of the male part 203a and the inner peripheral surfaces 3bi, 3b2, 3ba, 3b4 of the female part 3b' contact each other respectively, abutting against each other, to react said torque. With reference to Figure 5, in relation to each contacting surface 3bi, 3b2, 3ba, 3b4 of the female part 3b' , at at least one point along the surface 3bi, 3b2, 3ba, 3bd, the normal (N) to the surface extends in a direction that has a least a component (N' ) in the opposite direction to the local direction (T) of the torque exerted on female part, by the male part, that acts to try to cause relative rotation of the male and female parts about said rotational axis C. In this respect, the contacting surfaces of the male and female parts produce a reaction force (R) in a direction that has a least a component in the opposite direction to the local direction (T) of the torque exerted on the male and / or female parts that acts to try to cause relative rotation of the male and female parts about said rotational axis of the output rotational drive member. However, it will be appreciated that any suitable arrangement of contacting surfaces may be used. The male and female parts 203a, 3b' interlock such that said torque reaction is provided. The male and female parts 203a, 3b' interlock such that the interlocking of the male and female parts 203a, 3b' acts to prevent relative rotation of the male and female parts 203a, 3b' about the rotational axis C, in both rotational directions about the rotational axis C, and so provide said torque reaction when the applied rotational input torque is in either rotational direction. Alternatively, the male and female parts may arranged to only provide said torque reaction in one rotational direction, about the rotational axis C. The torque reaction, by the contacting surfaces, allows the attachment parts 203a, 3b' to be attached to each other with one or more fasteners 205 that may be tightened with a lower torque than would otherwise be necessary. Alternatively, or additionally, it may allow the fasteners 205 to be used without locking washers . This simplifies the installation and maintenance of the apparatus. Alternatively, or additionally provides a consistent and guaranteed joint strength. In the described embodiment, the attachments parts 203a, 3b' are square, i.e. a square male member is received in a square female member, to provide said interlocking, to provide said torque reaction. However, it will be appreciated that any suitable shape of the male and female parts may be used that provides said torque reaction, including rectangular, triangular, diamond, hexagonal, etc . Furthermore, in a reciprocal arrangement the attachment part of the gearbox housing may comprise the male part and the attachment part of the transmission housing may comprise the female part. In the described embodiment, a transmission 42 is provided to mechanically link the actuator 170 and the input rotational drive shaft 5 of the gear box 1. In this case, it will be appreciated that the input gear 30 is mechanically linked to the actuator 170 by the drive shaft 5 and the transmission 42. The transmission 42 and transmission housing 203 form a rotational drive transmitting device, with the planetary gears 201, disc 202 and connecting shaft 210 forming an output rotational drive member of the rotational drive transmitting device that rotates about the rotational axis C. In a second embodiment of the apparatus, shown in Figure 9, the actuator 170 is directly connected to the input rotational drive shaft 5 of the gearbox by a direct drive shaft 5' provided, at least partially, in the housing 203. The direct drive shaft 5' is coupled to the input rotational drive shaft 5 by any suitable coupling arrangement (e.g. protrusion and recess) such that the direct drive shaft 5' rotates the input rotational drive shaft 5. In this case, there is no gearing arrangement (i.e. there is no planetary gear transmission 42) . In this case, it will be appreciated that the input gear 30 is mechanically linked to the actuator 17 0 by the input rotational drive shaft 5 and the direct drive shaft 5'. It will be appreciated that the direct drive shaft 5' and its housing 203 form a rotational drive transmitting device, with the direct drive shaft 5' forming an output rotational drive member of the rotational drive transmitting device. Where a direct drive is used, the applied torque from the actuator 170 produces a torque on the housing 203 of the direct drive shaft 5' that acts to try and rotate the male part 203a relative to the female part 3b' , in an opposite rotational direction to that of the applied rotation, about the rotational axis C. Where a transmission 42 is used, any type of transmission may be used, including a planetary gear transmission, spur gear transmission, etc. The gearbox 1 comprises a second said attachment part 103b' on an opposite side of the housing 3. The second attachment part 103b' corresponds to the first attachment part 3a and is for attaching the attachment part 203a of the transmission, on the other side of the gearbox 1, in the same way, to allow the rotational drive shaft 5 to be driven from an opposite end of the shaft 5, in the opposite rotational direction about the rotational axis C, whilst providing said torque reaction. When the second said attachment part 103b' is not used, a square cover 77 is received in the square recess to cover the opening. The actuation device 41 also comprises a manually rotatable handwheel 169 that is mechanically linked to the rotational drive transmitting arrangement (of the rotational drive transmitting device) such that rotation of the handwheel 169 drives rotation of the rotational drive transmitting arrangement. This allows the valve to be manually operated, via the gearbox 1 (e.g. to change the position of the valve from a closed position to an open position, or vice-versa), either in normal operation or when a fault occurs with the actuation device 41. The actuation device may comprise the actuator 170 and / or the handwheel 169 (or any other manually operable actuation device). In this respect, the actuation device may comprise the handwheel 169 (or any other manually operable actuation device), without the actuator 170. Alternatively, the actuation device may comprise the actuator 170, without the handwheel 169 (or any other manually operable actuation device). Alternatively the actuation device may comprise the actuator 170 and the handwheel 169. It will be appreciated that numerous modifications to the above described design may be made without departing from the scope of the invention as defined in the appended claims. For example, in the described embodiment, the actuator is an electric motor. However, it will be appreciated that any suitable type of actuator may be used, including an electric actuator, a hydraulic actuator, a pneumatic actuator, etc. In the described embodiments the input rotational drive shaft 5 can be driven in both rotational directions about the rotational axis C, to rotate the valve member 50 in different directions. Alternatively, the input rotational drive shaft 5 could only be drivable in one rotational direction. The gearbox 1 may be provided without said torque reaction arrangement provided by said male and female attachment parts. The rotational drive transmitting device may be omitted. A direct drive may be used. In the described embodiment the sealed enclosure 11 is provided by the exterior of output gear mounting 9, the O-rings 12a, 12b and the housing seal 13. Alternatively, the housing seal 13 may be omitted, where a sealed enclosure is provided without the housing 13, for example where the housing 3 is formed as a single piece. In the described embodiment the input gear 30 directly engages with the output gear 8, to rotate the output gear 8. Alternatively, one or more intermediary gears may be provided between the input gear 30 and the output gear 8 such that the output gear 8 is rotatably driven by the input gear 30. In the described embodiment, the input gear 30 is a worm screw 30 and the output gear 8 is a worm gear quadrant 8. Alternatively, the input gear 30 may be a worm gear quadrant 8 and the output gear 8 a worm screw 30. Furthermore, any suitable gearing arrangement 4 may be used and is not limited to use of a worm screw 30 and worm gear quadrant 8. In this respect, the input gear could alternatively be a linear gear, such as rack, with the actuator 41 being arranged to move the linear gear linearly. The gearbox 1 may be used with any type of valve including, for example, heavy or light duty ball, plug or butterfly valves. In the described method of installation, the valve stem 7 is received through the valve stem insertion opening 15 into the interior of the output gear mounting member 9 (by mounting the gearbox 1 on the valve flange 98) before the output drive sleeve 6 is inserted through the sleeve insertion opening 14, into an interior of the output gear mounting member 9. This provides for ease of installation. However, alternatively, the valve stem 7 could be received through the valve stem insertion opening 15 into the interior of the output gear mounting member 9 (by mounting the gearbox 1 on the valve flange 98) after the output drive sleeve 6 is inserted through the sleeve insertion opening 14, into an interior of the output gear mounting member 9. However, this would provide for a more difficult installation process . Any type of coupling arrangement, to couple the output gear mounting member 9 and the sleeve 6 may be used, including a reciprocal male / female arrangement of splines to that of the described embodiment. Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims.

Claims

1. A gearbox for a valve, the gearbox comprising:a housing;a gear arrangement comprising an input gear and an output gear, the output gear being arranged to be rotatably driven by the input gear;the output gear being connected to an output gear mounting member such that rotation of the output gear rotates the output gear mounting member;the gearbox comprising a sealing arrangement configured to seal between the output gear mounting member and the housing such that a sealed enclosure is provided externally of the output gear mounting member, within the housing;the housing having a valve stem insertion opening, for a valve stem to be inserted through;wherein:the gearbox is configurable to have, or is configured in, an installation configuration in which a sleeve insertion opening is provided in the housing for inserting an output drive sleeve through, into an interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing;and the output gear mounting member comprises a coupling arrangement configured to couple the output gear mounting member to a said output drive sleeve, that is so inserted into the interior of the output gear mounting member, such that rotation of the output gear mounting member rotates the output drive sleeve,and wherein the valve stem insertion opening is for a valve stem to pass through, into the output drive sleeve, such that the output drive sleeve is couplable to the valve stem such that rotation of the output drive sleeve rotates the valve stem.

2. A gearbox according to claim 1, wherein the coupling arrangement is configured such that the output gear mounting member is so couplable to a said output drive sleeve by the insertion of the output drive sleeve into the interior of the output gear mounting member.

3. A gearbox according to claim 2, wherein the coupling arrangement comprises at least one formation that is for engaging with at least one formation of a said output drive sleeve by the insertion of the output drive sleeve into the interior of the output gear mounting member.

4. A gearbox according to any preceding claim, wherein the coupling arrangement is configured such that output gear mounting member is so couplable to the output drive sleeve in a plurality of rotational positions of the output drive sleeve relative to the output gear mounting member.

5. A gearbox according to claim 4, wherein the coupling arrangement comprises a plurality of formations distributedcircumferentially about an interior surface of the output gear mounting member, wherein the plurality of formations are for engaging with at least one formation of a said output drive sleeve in a plurality of rotational positions of the output drive sleeve relative to the output gear mounting member.

6. A gearbox according to any preceding claim, wherein the coupling arrangement is configured such that a said output drive sleeve may be selectively so coupled to and decoupled from the output gear mounting member.

7. A gearbox according to any preceding claim, wherein the gearbox comprises a closure member that is movable relative to the housing between an open position, in which the sleeve insertion opening is provided, to configure the gearbox in the installation configuration, and a closed position in which the sleeve insertion opening is closed by the closure member .

8. A gearbox according to claim 7, wherein the gearbox comprises a seal configured to provide a seal between the housing and the closure member, when the closure member is in said closed position.

9. A gearbox according to either of claims 7 or 8, wherein the gearbox comprises an indicator that is configured to indicate at least one position of said valve and wherein the closure member comprises at least part of the indicator.

10. A gearbox according to any preceding claim, wherein the sealing arrangement comprises:a first seal configured to provide a seal between the output gear mounting member and the housing at a first location on the output gear mounting member; anda second seal configured to provide a seal between the output gear mounting member and the housing at a second location on the output gear mounting member;wherein the first and second locations are spaced apart along the output gear mounting member such that said sealed enclosure is provided between the first and second seals .

11. A gearbox according to claim 10, wherein:the first seal is configured to prevent fluid from passing from the sealed enclosure, via the sleeve insertion opening, to the exterior of the housing;andthe second seal is configured to prevent fluid from passing from the sealed enclosure, via the valve stem insertion opening, to the exterior of the housing.

12. A gearbox according to any preceding claim, wherein:a first part of the output gear mounting member is arranged to rotate within the sleeve insertion opening;anda second part of the output gear mounting member isarranged to rotate within the valve stem insertion opening.

13. A gearbox according to claim 12, when dependent on either of claims 10 or 11, wherein the first seal provides a seal between the first part of the output gear mounting member and the housing and the second seal provides a seal between the second part of the output gear mounting memberand the housing.

14. A gearbox according to any preceding claim, wherein:the housing has first and second parts;the first and second parts are selectively attachable to and detachable from each other and when the first part is detached from the second part, the first part is movable relative to the second part between a closed position and an open position;when the first part is in the open position, the output gear mounting member can be received in the housing and rotatably mounted to the housing such that rotation of the output gear rotates the output gear mounting member, andwhen the first part is in the closed position, with the first part attached to the second part, the sealing arrangement provides said seal between the output gear mounting member and the housing.

15. A gearbox according to claim 14, wherein the gearbox comprises a housing sealing arrangement configured such that, when the first part is in the closed position and attached to the second part, a seal is provided between the first and second parts such that said sealed enclosure is provided externally of the output gear mounting member, within the housing.

16. A gearbox according to any preceding claim, wherein the output gear and / or input gear is provided in the sealed enclosure .

17. A gearbox according to claim 16, wherein the gear arrangement is provided in the sealed enclosure.

18. A gearbox according to any preceding claim, wherein:the gearbox comprises an output drive sleeve for receiving a valve stem and coupling to the valve stem such that rotation of the output drive sleeve rotates the valve stem;wherein, when the gearbox is in the installation configuration, the output drive sleeve is insertable through the sleeve insertion opening into the interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing;and wherein the output drive sleeve comprises a coupling arrangement configured to couple the output drive sleeve to the coupling arrangement of the output gearmounting member, such that rotation of the output gear mounting member rotates the output drive sleeve;wherein the output drive sleeve is provided in the interior of the output gear mounting member and is so coupled to the output gear mounting member by said coupling arrangement.

19. A gearbox according to claim 19, when dependent directly or indirectly on claim 2, wherein the coupling arrangement of the output drive sleeve and the coupling arrangement of the output gear mounting member are configured such that the output gear mounting member is so couplable to the output drive sleeve by the insertion of the output drive sleeve into the interior of the output gear mounting member.

20. A gearbox according to either of claims 18 or 19, when dependent directly or indirectly on claim 3, wherein the coupling arrangement of the output drive sleeve comprises at least one formation that is for engaging with at least one formation of the coupling arrangement of the output gear mounting member by the insertion of the output drive sleeve into the interior of the output gear mounting member.

21. A gearbox according to any of claims 18 to 20, when dependent directly or indirectly on claim 4, wherein the coupling arrangement of the output drive sleeve and the coupling arrangement of the output gear mounting member are configured to allow for said coupling of the output gear mounting member to the output drive sleeve in a pluralityof rotational positions of the output drive sleeve relative to the output gear mounting member.

22. A gearbox according to any of claims 18 to 21, when dependent directly or indirectly on claim 5, wherein the coupling arrangement of the output drive sleeve comprises a plurality of formations distributed circumferentially about an exterior surface of the output drive sleeve, wherein the plurality of formations are for engaging with the plurality of formations distributed circumferentially about the interior surface of the output gear mounting member in a plurality of rotational positions of the output drive sleeve relative to the output gear mounting member.

23. A gearbox according to any of claims 18 to 22, when dependent directly or indirectly on claim 6, wherein the coupling arrangement of the output drive sleeve and the coupling arrangement of the output gear mounting member are configured such that the output drive sleeve may be selectively coupled to and decoupled from the output gear mounting member.

24. A gearbox according to any of claims 18 to 23, wherein the output drive sleeve comprises a coupling arrangement for coupling the output drive sleeve to a coupling arrangement of a valve stem such that rotation of the output drive sleeve rotates the valve stem.

25. A gearbox according to any preceding claim, wherein the gear arrangement comprises a worm drive.26.A gearbox according to claim 25, wherein:the worm drive comprises a worm screw and a worm gearengaged with the worm screw; andwherein one of the input gear and the output gear comprises the worm screw and the other comprises the worm gear .

27. A gearbox according to claim 26, wherein:the input gear comprises the worm screw and the output gear comprises the worm gear.

28. A gearbox according to any of claims 25 to 27, wherein the worm drive is a quarter turn worm drive and the worm gear is a worm gear quadrant.

29. A gearbox according to any preceding claim, whereinthe gearbox comprises an input drive member and wherein the input gear is coupled to the input drive member such that the input drive member drives the input gear such that theoutput gear is rotated.

30. A gearbox and actuation device assembly comprising:a gearbox according to claim 29; andan actuation device;wherein the actuation device is mechanically linked to the input drive member such that the actuation device drives the input drive member to drive the input gear such that the output gear is rotated.

31. A gearbox according to any preceding claim, wherein the input gear is configured to be rotatably driven and wherein the output gear is arranged to be rotatably driven by the rotation of the input gear.

32. A valve and gearbox assembly comprising:a gearbox according to claim 18, or any of claims 18 to 31 when dependent on claim 18, anda valve comprising a valve member and a valve stem that is coupled to the valve member such that rotation of the valve stem rotates the valve member to operate the valve;whereinthe valve stem is received within the output drive sleeve and output drive sleeve is coupled to the valve stem such that rotation of the output drive sleeve rotates the valve stem, to operate the valve.

33. A kit of parts of a gearbox for a valve, the kit of parts comprising:a housing;a gear arrangement comprising an input gear and an output gear, the output gear being for being rotatably driven by the input gear;the output gear being connected to, or connectable to, an output gear mounting member such that rotation of the output gear rotates the output gear mounting member;the gearbox comprising a sealing arrangement for sealing between the output gear mounting member and the housing such that a sealed enclosure is provided externally of the output gear mounting member, within the housing;the housing having a valve stem insertion opening, for a valve stem to be inserted through;wherein:the gearbox is configurable to have, or is configured in, an installation configuration in which a sleeve insertion opening is provided in the housing for inserting an output drive sleeve through, into an interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing;and the output gear mounting member comprises a coupling arrangement configured to couple the output gear mounting member to a said output drive sleeve, that is so inserted into the interior of the output gear mounting member, such that rotation of the output gear mounting member rotates the output drive sleeve,and wherein the valve stem insertion opening is for a valvestem to be inserted through, into the output drive sleeve, suchthatthe output drive sleeve is couplable to the valve stem suchthat rotation of the output drive sleeve rotates the valve stem.

34. A kit of parts according to claim 33, wherein the kit of parts comprises:an output drive sleeve for receiving a valve stem and coupling to the valve stem such that rotation of the output drive sleeve rotates the valve stem;wherein, when the gearbox is in the installation configuration, the output drive sleeve is insertable through the sleeve insertion opening into the interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing;and wherein the output drive sleeve comprises a coupling arrangement configured to couple the output drive sleeve to the coupling arrangement of the output gear mounting member, such that rotation of the output gear mounting member rotates the output drive sleeve.

35. A kit of parts of a gearbox for a valve, the kit ofparts comprising:a gearbox according to any of claims 1 to 17; anda) an output drive sleeve for receiving a valve stem and coupling to the valve stem such that rotation of the output drive sleeve rotates the valve stem;wherein, when the gearbox is in the installation configuration, the output drive sleeve isinsertable through the sleeve insertion opening into the interior of the output gear mounting member, whilst said seal is provided between the 5 output gear mounting member and the housing; and wherein the output drive sleeve comprises a coupling arrangement configured to couple the output drive sleeve to the coupling arrangement of the output gear mounting member, such that rotation 10 of the output gear mounting member rotates the output drive sleeve; or 15 b) a sleeve formation part for having at least part of its interior removed such that the sleeve formation part forms an output drive sleeve for receiving a valve stem and coupling to the valve stem such that rotation of the output drive sleeve rotates the 20 valve stem; wherein, when the gearbox is in the installation configuration, the output drive sleeve is insertable through the sleeve insertion opening 25 into the interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing; and wherein the output drive sleeve comprises a 30 coupling arrangement configured to couple the output drive sleeve to the coupling arrangement of the output gear mounting member, such that rotationof the output gear mounting member rotates the output drive sleeve.

36. A valve gearbox installation system comprising: 5 a gearbox according to any of claims 1 to 17; and a) an output drive sleeve for receiving a valve stem and coupling to the valve stem such that rotation of the output drive sleeve rotates the valve stem; 10 wherein, when the gearbox is in the installation configuration, the output drive sleeve is insertable through the sleeve insertion opening into the interior of the output gear mounting 15 member, whilst said seal is provided between the output gear mounting member and the housing; and wherein the output drive sleeve comprises a coupling arrangement configured to couple the 20 output drive sleeve to the coupling arrangement of the output gear mounting member, such that rotation of the output gear mounting member rotates the output drive sleeve; 25 or b) a sleeve formation part for having at least part of its interior removed such that the sleeve formation part forms an output drive sleeve for receiving a 30 valve stem and coupling to the valve stem such that rotation of the output drive sleeve rotates the valve stem;wherein, when the gearbox is in the installation configuration, the output drive sleeve is insertable through the sleeve insertion opening into the interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing;and wherein the output drive sleeve comprises a coupling arrangement configured to couple the output drive sleeve to the coupling arrangement of the output gear mounting member, such that rotation of the output gear mounting rotates the output drive sleeve .

37. An output drive sleeve for receiving a valve stem and coupling to the valve stem such that rotation of the output drive sleeve rotates the valve stem;wherein the output drive sleeve comprises a coupling arrangement for coupling the output drive sleeve to a coupling arrangement of an output gear mounting member, such that rotation of the output gear mounting member rotates the output drive sleeve.

38. A sleeve formation part for having at least part of its interior removed such that the sleeve formation part forms an output drive sleeve according to claim 37.

39. A method of assembly of a gearbox for a valve,comprising:• providing a housing;• providing a gear arrangement comprising an input gear and an output gear, the output gear being arranged to be rotatably driven by the input gear, the output gear being connected to an output gear mounting member;• rotatably mounting the output gear mounting member to the housing such that rotation of the output gear rotates the output gear mounting member;wherein:the gearbox is configurable to have, or is configured in, an installation configuration in which a sleeve insertion opening is provided in the housing for inserting an output drive sleeve through, into an interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing;and the output gear mounting member comprises a coupling arrangement configured to couple the output gear mounting member to a said output drive sleeve, that is so inserted into the interior of the output gear mounting member, such that rotation of the output gear mounting member rotates the output drive sleeve,and wherein the valve stem insertion opening is for a valvestem to pass through, into the output drive sleeve, such thatthe output drive sleeve is couplable to the valve stem such thatrotation of the output drive sleeve rotates the valve stem.

40. A method of assembly of a gearbox according to claim 39, wherein:the housing has first and second parts;the first and second parts are selectively attachable to and detachable from each other and when the first part is detached from the second part, the first part is movable relative to the second part between a closed position and an open position;wherein:the output gear mounting member is rotatably mounted to the housing such that rotation of the output gear rotates the output gear mounting member, when the first part is in the open position.

41. A method of assembly of a gearbox according to claim40, wherein:after the output gear mounting member has been rotatably mounted to the housing, the first part is moved from the open position to the closed position and the first part attached to the second part, in the closed position;wherein when the first part is in the closed position, the sealing arrangement provides said seal between the output gear mounting member and the housing.

42. A method according to any of claims 39 to 41, wherein the method comprises:• providing an output drive sleeve;• configuring the gearbox in an installation configuration in which a sleeve insertion opening is provided in the housing;• inserting the output drive sleeve through the sleeve insertion opening, into an interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing;• coupling the output gear mounting member to the output drive sleeve such that rotation of the output gear mounting member rotates the output drive sleeve.

43. A method of installation of a gearbox with a valve, the method comprising:providing an output drive sleeve;providing a gearbox for a valve, the gearbox comprising:a housing;a gear arrangement comprising an input gear and an output gear, the output gear being arranged to be rotatably driven by the input gear;the output gear being connected to an output gear mounting member such that rotation of the output gear rotates the output gear mounting member;the gearbox comprising a sealing arrangement configured to seal between the output gear mounting member and the housing such that a sealed enclosure is provided externally of the output gear mounting member, within the housing;the housing having a valve stem insertion opening, for a valve stem to be inserted through;wherein the method further comprises:• configuring the gearbox in an installation configuration in which a sleeve insertion opening is provided in the housing;• inserting a valve stem through the valve stem insertion opening into the interior of the output gear mounting member;• inserting the output drive sleeve through the sleeve insertion opening, into an interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing;• coupling the output gear mounting member to the output drive sleeve such that rotation of the output gear mounting member rotates the output drive sleeve;• receiving the valve stem in the output drive sleeve tocouple the output drive sleeve to the valve stem suchthat rotation of the output drive sleeve rotates thevalve stem.

44. A method according to claim 43, wherein the output drive sleeve is coupled to the output gear mounting member in a rotational position relative to the valve stem such that the valve stem can be received by the output drive sleeve and coupled to the output drive sleeve in said relative rotational position.

45. A method according to either of claims 43 or 44, wherein the valve stem is inserted through the valve stem insertion opening before the output drive sleeve is coupledto the output gear mounting member.

46. A method of supplying a gearbox installation systemfor a valve, the method comprising:supplying a gearbox;supplying an output drive sleeve or a sleeve formation part for having at least part of its interior removed such that the sleeve formation part forms an output drive sleeve;wherein the gearbox comprises:a housing;a gear arrangement comprising an input gear and an output gear, the output gear being arranged to be rotatably driven by the input gear;the output gear being connected to an output gear mounting member such that rotation of the output gear rotates the output gear mounting member;the gearbox comprising a sealing arrangement configured to seal between the output gear mounting member and the housing such that a sealed enclosure is provided externally of the output gear mounting member, within the housing;the housing having a valve stem insertion opening, for a valve stem to be inserted through;wherein:the gearbox is configurable to have, or is configured in, an installation configuration in which a sleeve insertion opening is provided in the housing for inserting the output drive sleeve through, into an interior of the output gear mounting member, whilst said seal is provided between the output gear mounting member and the housing;and the output gear mounting member comprises a coupling arrangement configured to couple the output gear mounting member to the output drive sleeve, that is so inserted into the interiorof the output gear mounting member, such that rotation of the output gear mounting member rotates the output drive sleeve,and wherein the valve stem insertion opening is for a valve stem to pass through, into the output drive sleeve, such that the output drive sleeve is couplable to the valve stem such that rotation of the output drive sleeve rotates the valve stem.

47. A method according to claim 46, wherein the method comprises :removing at least part of the interior of a sleeve formation part such that the sleeve formation part forms an output drive sleeve comprising a coupling arrangement for coupling the output drive sleeve to a coupling arrangement of a valve stem such that rotation of the output drive sleeve rotates the valve stem.

48. A method according to claim 47 wherein the coupling arrangement of the output drive sleeve is configured to couple to a specific valve stem.

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