Magnetic transmission arrangement for a power tool, power tool comprising said transmission arrangement and associated systems and methods

Abstract

A magnetic transmission arrangement (10) for a power tool (100) such as a powered marine growth removal tool comprises a drive member (12) configured for coupling to, forming part of or operatively as

Description

FIELD This relates to a magnetic transmission arrangement for a power tool, in particular a powered marine growth removal tool; to a power tool comprising said magnetic transmission arrangement, and to associated systems and methods. BACKGROUND A wide range of industrial and / or leisure activities take place within the marine environment and are thus subject to the technical challenges associated with withstanding the often harsh conditions present. One such challenge is the susceptibility of portions of marine structures and / or vessels which are, permanently or periodically, located below the water line to the growth of marine organisms on their surfaces, commonly known as marine growth. Examples of marine structures commonly affected by marine growth include offshore energy infrastructure, such as offshore oil and gas platforms and / or structures responsible for supporting offshore wind or tidal turbines such as monopoles or the like, but also static structures such as jetties, seawalls, and launching ramps. Amongst other things, such marine growth may be detrimental to the safe and efficient operation of the relevant structure or vessel itself, to the safety of personnel working in and / or around such structures or vessels as well as to the surrounding environment. For example, the proliferation of marine growth may lead to increased corrosion of metal components provided on or forming part (often a structurally critical part) of the structure or vessel. Moreover, the presence of marine growth on the surfaces of such structures and / or vessels may also conceal other forms of damage, thereby inhibiting or in some cases preventing such damage from being identified and remedied. The presence of marine growth may also increase structural load forces on the structure, thereby increasing the risk of structural damage and / or reducing operational lifetime; this in an environment which already poses significant limitations on structural lifetime due to exposure to the harsh marine environment. Moreover, for mobile structures and / or vessels the presence of marine growth on surfaces exposed to fluid flow is known to increase drag. This may in turn reduce fuel efficiency and / or impact on journey times, e.g. to the detriment of operational efficiency and / or availability of the structure or vessel, and more generally be contrary to the desire to reduce the carbon footprint and / or environmental impacts associated with marine operations. With a view to alleviating the negative consequences associated with marine growth, divers are typically employed to clean and / or otherwise remove marine growth from marine structures and / or vessels using a variety of handheld tools such as cloths, brushes, scraping tools, powered rotary brush system or high pressure waterjets. Cloths, brushes and scraping tools, whilst having the advantage of being mechanically simple to construct and operate, are labour and time intensive. In addition to increasing downtime and associated costs of the structure or vessel being cleaned, such labour and time intensive work exposes the divers to the marine environment for longer periods of time, with consequential increased safety concerns. Cloths, brushes and scraping tools have also been found to be ineffective in the removal of hardened marine growth. While powered rotary brush and high pressure waterjet systems offer improved performance in terms of labour and time, such tools are often not suited to prolonged use, in particular in the marine environment. For example, in view of the forces and / or actions involved in removing marine growth from a given surface rotary brush systems are subject to considerable wear and thus in practice have limited utility and / or operational lifetime. In the case of hydraulic and / or pneumatic tools, these are typically powered via an umbilical hose extending above the water line (whether on the surface of the marine vessel or structure itself, or on some other surface). Umbilical arrangements are intrinsically large and cumbersome and can be restrictive to diver movement underwater, limiting their utility and again leading to potential health and safety risks. SUMMARY Aspects of the present disclosure relate to a magnetic transmission arrangement for a power tool, such as a marine growth removal tool; to a tool comprising the transmission arrangement, and to associated systems and methods. According to a first aspect, there is provided a magnetic transmission arrangement for a power tool such as a powered marine growth removal tool, the magnetic transmission arrangement comprising: a drive member configured for coupling to, forming part of or operatively associated with a rotary drive arrangement of the power tool, wherein the drive member comprises one or more magnetic elements disposed thereon; and a driven member configured for coupling to, forming part of or operatively associated with a tool head of the power tool, wherein the driven member comprises one or more magnetic elements disposed thereon, wherein the driven member is spaced from the drive member, and wherein the magnetic transmission arrangement is configured to convert rotation of the drive member by the rotary drive arrangement into linear movement of the driven member. In use, rotation of the drive member by the rotary drive arrangement is converted by the transmission arrangement into linear movement of the driven member, in particular oscillatory movement of the driven member. More particularly, rotation of the drive member about its axis of rotation causes the one or more magnetic elements disposed thereon to process around the axis of rotation, thereby exposing the one or more magnetic elements of the driven member to a repelling force (where exposed to a magnetic element of the drive member of the same polarity) or an attractive force (where exposed to a magnetic element of the drive member of the opposing polarity). This linear, e.g. oscillatory, movement of the driven member causes the associated tool head of the power tool to move linearly, e.g. oscillate. In particular embodiments, the power tool may comprise or take the form of a powered marine growth removal tool, and said linear, e.g. oscillatory, movement of the driven member causes the associated tool head of the marine growth removal tool to move linearly, e.g. oscillate, thereby facilitating removal of marine growth from a marine structure or vessel. However, it will be understood that the magnetic transmission arrangement may be utilised in a wide variety of tools and / or applications. Beneficially, the present transmission arrangement facilitates the conversion of a rotary input into a linear, e.g. oscillatory, output, without relying on the physical interaction between the drive member and driven member. Amongst other things, the transmission arrangement may thus obviate or at least mitigate the wear associated with conventional tools and equipment. This, in turn, may facilitate prolonged operational lifetime and / or increased utility due e.g. to reduced need for repair, maintenance and replacement of the transmission arrangement. Furthermore, the transmission arrangement may obviate or at least mitigate any frictional power losses which might otherwise occur, as well as any noise which might otherwise be produced. The transmission of vibrations from the tool head in use, through the driven member and into the drive member and the rotary drive arrangement is also obviated or at least mitigated by the transmission arrangement. Thus, damage to the internal motor structure may be obviated or at least mitigated, as well as any damage sustained by the user, e.g. to the fingers or to the wrist of the user. Moreover, the transmission arrangement permits the drive member and associated components to be physically isolated from the driven member and associated components. The present transmission arrangement is particularly beneficial for tools and / or applications utilised in harsh and / or remote environments, such as the marine environment. For example, where the transmission arrangement is utilised as part of a marine growth removal tool, the transmission arrangement facilitates the conversion of a rotary input into a linear, e.g. oscillatory, output which provides for the highly effective removal of marine growth. Moreover, the transmission arrangement may obviate or at least mitigate the wear associated with conventional marine growth removal tools and equipment, facilitating prolonged operational lifetime and / or increased utility due e.g. to reduced need for repair, maintenance and replacement of the transmission arrangement. This may facilitate an increase in the amount of marine growth that can be removed during a given operation and thus reduce overall time that operatives, e.g. divers, are exposed to the harsh marine environment. The transmission arrangement may alternatively or additionally obviate or reduced the need for umbilical arrangements that are intrinsically large and cumbersome and can be restrictive to diver movement underwater, otherwise limiting utility and leading to potential health and safety risks. The above benefits may in turn reduce the risk of corrosion of metal components provided on or forming part (often a structurally critical part) of marine structures or vessels and / or reduce the likelihood that damage may go unidentified and remedied. The one or more magnetic elements of the drive member may comprise at least one first magnetic element of a first polarity. The one or more magnetic elements of the drive member may comprise at least one second magnetic element of a second, opposing, polarity. In particular embodiments, the drive member may comprise a plurality of the magnetic elements disposed thereon. In particular embodiments, the drive member may comprise at least one first magnetic element of the first polarity and at least one second magnetic element of the second, opposing, polarity. In particular embodiments, the magnetic elements may be arranged so that the polarity of the magnetic elements alternates. More particularly, but not exclusively, the magnetic elements may be arranged so that the polarity of successive magnetic elements alternates, e.g. north pole, south pole, north pole, etc. However, it will be understood that other arrangements may be provided, e.g. north pole, north pole, south pole, south pole, north pole, north pole etc. Alternatively, the drive member may comprise a plurality of magnetic elements, all of the magnetic elements being of the same polarity, e.g. all north poles or all south poles. The magnetic elements may be circumferentially arranged and / or spaced. The magnetic elements may be arranged in one or more rows., e.g. concentric rows. At least one of the magnetic elements may comprise or take the form of a permanent magnet. In particular embodiments, at least one of the magnetic elements may comprise or take the form of a neodymium magnet. Alternatively or additionally, at least one of the magnetic elements may comprise or take the form of: a samarium-cobolt magnet; an alnico magnet; or any other suitable permanent magnet. Alternatively or additionally, at least one of the magnetic elements may comprise or take the form of an electromagnet. As described above, the magnetic transmission arrangement comprises a drive member configured for coupling to, forming part of or operatively associated with a rotary drive arrangement of the power tool. The drive member may be coupled, e.g. directly or indirectly coupled, to the rotary drive arrangement. In particular embodiments, the drive member may be coupled, e.g. directly or indirectly coupled, to a drive shaft of the rotary drive arrangement. The drive member may comprise a body portion (“drive member body portion”). The drive member body portion may be coupled, e.g. directly or indirectly coupled, to the rotary drive arrangement. In particular embodiments, the drive member body portion may be coupled, e.g. directly or indirectly coupled, to the drive shaft of the rotary drive arrangement. The drive member body portion may be cylindrical or substantially cylindrical. The drive member body portion may comprise or take the form of a disc. The drive member body portion may comprise an inner surface. In use, the inner surface of the drive member body portion may define a proximal surface, i.e. closer to the rotary drive arrangement. The drive body portion may comprise an outer surface. In use, the outer surface of the drive member body portion may define a distal surface, i.e. further from to the rotary drive arrangement. The outer surface may be orientated to face the driven member. As described above, the drive member comprises one or more magnetic elements disposed thereon. In particular embodiments, the drive member body portion may comprise one or more recesses, e.g. pockets or apertures, for receiving the magnetic elements. Each recess may receive a single magnetic element or a plurality of the magnetic elements. The recesses may be formed or otherwise provided in the drive member body portion. In particular, the recesses may be formed or otherwise provided in the outer surface of the drive member body portion. The one or more recesses may be configured, e.g. dimensioned, shaped or otherwise constructed, to receive the magnetic elements. At least one of the recesses may be cylindrical or substantially cylindrical. However, it will be understood that the recesses may take any suitable form, e.g. rectangular or substantially rectangular, segment-shaped or the like. In particular embodiments, the drive member body portion may comprise a plurality of the recesses. The recesses may be circumferentially arranged and / or spaced. The recesses may be arranged in one or more rows, e.g. concentric rows. Alternatively, the drive member body portion may comprise a single recess for receiving the plurality of magnetic elements. Alternatively, the magnetic elements may be secured to the drive member body portion. For example, the magnetic elements may be secured to the drive member body portion by a coupling arrangement, e.g. one or more mechanical fasteners, adhesive bond, or other suitable coupling. The transmission arrangement may comprise a housing (“drive member housing”) for receiving the drive member. The drive member housing may be cylindrical or substantially cylindrical. As described above, the magnetic transmission arrangement comprises a driven member configured for coupling to, forming part of or operatively associated with a tool head of the power tool, the driven member comprising one or more magnetic elements disposed thereon. The one or more magnetic elements of the driven member may comprise at least one first magnetic element of the first polarity. The one or more magnetic elements of the driven member may comprise at least one second magnetic element of the second, opposing, polarity. In particular embodiments, the driven member may comprise a plurality of the magnetic elements disposed thereon. In particular embodiments, the driven member may comprise at least one first magnetic element of the first polarity and at least one second magnetic element of the second, opposing, polarity. In particular embodiments, the magnetic elements may be arranged so that the polarity of the magnetic elements alternates. More particularly, but not exclusively, the magnetic elements may be arranged so that the polarity of successive magnetic elements alternates, e.g. south pole, south pole, north pole, etc. However, it will be understood that other arrangements may be provided, e.g. north pole, north pole, south pole, south pole, north pole, north pole etc. Alternatively, the driven member may comprise a plurality of magnetic elements, all of the magnetic elements being of the same polarity, e.g. all north poles or all south poles. The magnetic elements may be circumferentially arranged and / or spaced. The magnetic elements may be arranged in one or more rows., e.g. concentric rows. At least one of the magnetic elements may comprise or take the form of a permanent magnet. In particular embodiments, at least one of the magnetic elements may comprise or take the form of a neodymium magnet. Alternatively or additionally, at least one of the magnetic elements may comprise or take the form of: a samarium-cobolt magnet; an alnico magnet; or any other suitable permanent magnet. Alternatively or additionally, at least one of the magnetic elements may comprise or take the form of an electromagnet. As described above, in use, rotation of the drive member by the rotary drive arrangement is converted by the transmission arrangement into linear movement of the driven member, in particular oscillatory movement of the driven member. More particularly, rotation of the drive member about its axis of rotation causes the magnetic elements disposed thereon to process around the axis of rotation, thereby exposing the magnetic elements of the driven member to a repelling force (where exposed to a magnetic element of the drive member of the same polarity) or an attractive force (where exposed to a magnetic element of the drive member of the opposing polarity). This linear, e.g. oscillatory, movement of the driven member causes the associated tool head of the power tool to move linearly, e.g. oscillate. The driven member may be coupled, e.g. directly or indirectly coupled, to the tool head. The driven member may comprise a body portion (“driven member body portion”). The driven member body portion may be coupled, e.g. directly or indirectly coupled, to the tool head. The driven member body portion may be cylindrical or substantially cylindrical. The driven member body portion may comprise or take the form of a disc. Alternatively, the driven member body portion may be a non-cylindrical shape. For example, the driven member body portion may be a polygonal shape in cross section e.g. rectangular or substantially rectangular, hexagonal or substantially hexagonal, or octagonal or substantially octagonal. The driven member body portion may comprise an inner surface. In use, the inner surface of the drive member body portion may define a proximal surface, i.e. closer to the drive member. The inner surface may be orientated towards the drive member. The driven body portion may comprise an outer surface. In use, the outer surface of the driven member body portion may define a distal surface, i.e. further from the drive member. The outer surface may be orientated towards the tool head. In particular embodiments, the driven member body portion may comprise one or more recesses, e.g. pockets or apertures, for receiving the magnetic elements. Each recess may receive a single magnetic element or a plurality of the magnetic elements. The recesses may be formed in the driven member body portion. In particular, the recesses may be provided in the inner surface of the driven member body portion. The one or more recesses may be configured, e.g. dimensioned, shaped or otherwise constructed, to receive the magnetic elements. At least one of the recesses may be cylindrical or substantially cylindrical. However, it will be understood that the recesses may take any suitable cross-sectional form, e.g. rectangular or substantially rectangular, segment-shaped or the like. In particular embodiments, the driven member body portion may comprise a plurality of the recesses. The recesses may be circumferentially arranged and / or spaced. The recesses may be arranged in one or more rows, e.g. concentric rows. Alternatively, the driven member body portion may comprise a single recess for receiving the plurality of magnetic elements. Alternatively, the magnetic elements may be secured to the driven member body portion. For example, the magnetic elements may be secured to the driven member body portion by a coupling arrangement, e.g. one or more mechanical fasteners, adhesive bond, or other suitable coupling. The driven member may comprise a shaft. In use, the shaft may transmit the linear, e.g. oscillatory, movement of the driven member to the tool head. The shaft may form part of or may be coupled to the driven member body portion. The shaft may form part of or may be coupled to the tool head. In particular embodiments, the shaft may be hollow in construction. The shaft may be aligned or substantially aligned with a central axis of the driven body portion. The shaft may be cylindrical or substantially cylindrical. Alternatively, the shaft may be a non-cylindrical shape. For example, the shaft may be a polygonal shape in cross section e.g. rectangular or substantially rectangular, hexagonal or substantially hexagonal, or octagonal or substantially octagonal. The transmission arrangement may comprise a housing (“driven member housing”) for receiving the driven member. The driven member housing may be cylindrical or substantially cylindrical. The driven member housing may be configured, e.g. dimensioned, shaped or otherwise constructed, to receive the driven member. The driven member housing may be configured e.g. dimensioned, shaped or otherwise constructed, to receive the drive member body portion. For example, an interior wall portion of the driven member housing may be configured to receive the drive member body portion. Alternatively, the driven member housing may be configured to receive a sleeve or insert configured to receive the drive member body portion. The provision of a sleeve or insert may for example facilitate simpler manufacture of the transmission arrangement and / or may facilitate the use of different driven members with a common driven member housing. In particular, the shape of the driven member housing, sleeve or insert may be configured, e.g. to match, the shape of the drive member body portion so as to form or form part of an arrangement for preventing or substantially preventing rotation of the driven member in response to rotation of the drive member, as will be described further below. The driven member housing may be configured, e.g. dimensioned, shaped or otherwise constructed, to receive the shaft of the driven member. For example, the driven member housing may comprise an axial channel. The axial channel may be formed in a distal end surface of the driven member housing. The shaft of the driven member may extend through the axial channel. An interior wall portion of the axial channel may be configured to receive the shaft. Alternatively, the driven member housing may be configured to receive a sleeve or insert configured for location in the axial channel and to receive the shaft. The provision of a sleeve or insert may for example facilitate simpler manufacture of the transmission arrangement and / or may facilitate the use of different driven members with a common driven member housing. The axial channel may be cylindrical or substantially cylindrical. Alternatively, a non-cylindrical shape. For example, the shaft may be a polygonal shape in cross section e.g. rectangular or substantially rectangular, hexagonal or substantially hexagonal, or octagonal or substantially octagonal. In particular, the shape of the axial channel, sleeve or insert may be configured, e.g. to match, the shape of the shaft so as to form or form part of the arrangement for preventing or substantially preventing rotation of the driven member in response to rotation of the drive member. The drive member and the driven member may be aligned or substantially aligned. The drive member and the driven member may be arranged co-linearly. The transmission arrangement may be configured such that the outer surface of the drive member is parallel or substantially parallel to the inner surface of the driven member. The transmission arrangement may be configured and / or operable so that the frequency of the oscillatory motion of the driven member is variable. For example, the frequency may be variable by adapting the configuration of the magnetic elements of the drive member and / or driven member. For example, where the rotary drive arrangement rotates at 1000 rpm, where the drive magnetic arrangement and the driven magnetic arrangement each comprise two magnetic elements as discussed above, the frequency of the linear motion of the driven member shall be 1000 cycles per minute. Where the number of magnetic elements comprised in each of the drive and the driven magnetic arrangements is increased to four, the frequency shall be 2000 cycles per minute. Where the number of magnetic elements comprised in each of the drive and the driven magnetic arrangements is increased to six, the frequency shall be 3000 cycles per minute. As described above, the magnetic transmission arrangement is configured to convert rotation of the drive member by the rotary drive arrangement into linear movement of the driven member. The transmission arrangement may be configured and / or operable to convert rotation of the drive member into solely linear motion or substantially solely linear motion of the driven member. The transmission arrangement may comprise an arrangement for preventing or substantially preventing rotation of the driven member. The arrangement may comprise a rotational lock. Beneficially, the arrangement for preventing or substantially preventing rotation of the driven member, e.g. rotational lock, may permit linear, e.g. oscillatory, movement of the driven member in response to rotation of the drive member but prevent or substantially prevent rotation of the driven member. The arrangement for preventing or substantially preventing rotation of the driven member, e.g. rotational lock, may comprise or take the form of a spline arrangement. The arrangement for preventing or substantially preventing rotation of the driven member, e.g. rotational lock, may comprise or take the form of a key arrangement. The arrangement for preventing or substantially preventing rotation of the driven member, e.g. rotational lock, may comprise or take the form of a cam and follower arrangement. The arrangement for preventing or substantially preventing rotation of the driven member, e.g. rotational lock, may comprise one or more protrusions, e.g. elongate protrusions, coupled to or forming part of the driven member body portion. At least one of the protrusions may extend radially outwardly from the driven member body portion. At least one of the protrusions may be configured to engage a groove or slot formed or otherwise provided in the driven member housing. Alternatively or additionally, the arrangement, e.g. rotational lock, may comprise a bearing arrangement. The bearing arrangement may be interposed between the driven member body portion and the driven member housing. The bearing arrangement may comprise one or more bearings disposed in and extending outwards from the driven member body portion. At least one of the bearings may be configured to engage a groove or slot formed or otherwise provided in the driven member housing. In particular embodiments, at least one on the bearings may comprise or take the form of a ball bearing, e.g. a steel ball bearing. Alternatively, at least one on the bearings may comprise or take the form of a roller bearing. Alternatively or additionally, the arrangement for preventing or substantially preventing rotation of the driven member, e.g. rotational lock, may be formed by the shape of the driven member body portion and the driven member housing and / or the shape of the shaft of the driven member and the axial bore of the driven member housing. For example, the receipt of a non-cylindrical driven member body portion within a non-cylindrical housing prevents or substantially prevents the rotation of the driven member. Alternatively or additionally, the receipt of a non-cylindrical shaft within a non-cylindrical channel prevents or substantially prevents the rotation of the driven member. As described above, the magnetic transmission arrangement is configured to convert rotation of the drive member by the rotary drive arrangement into linear movement of the driven member. In other embodiments, the magnetic transmission arrangement may be configured to convert rotation of the drive member into linear and rotational movement of the driven member. The magnetic transmission arrangement may comprise an arrangement for converting rotation of the drive member by the rotary drive arrangement into linear and rotational movement of the driven member. The arrangement for preventing or substantially preventing rotation of the driven member, e.g. rotational lock, may comprise or take the form of a key arrangement. The arrangement for preventing or substantially preventing rotation of the driven member, e.g. rotational lock, may comprise or take the form of a cam and follower arrangement. The arrangement for preventing or substantially preventing rotation of the driven member, e.g. rotational lock, may comprise one or more protrusions, e.g. elongate protrusions, coupled to or forming part of the driven member body portion. At least one of the protrusions may extend radially outwardly from the driven member body portion. At least one of the protrusions may be configured to engage a groove or slot formed or otherwise provided in the driven member housing. Alternatively or additionally, the arrangement, e.g. rotational lock, may comprise a bearing arrangement. The bearing arrangement may be interposed between the driven member body portion and the driven member housing. The bearing arrangement may comprise one or more bearings disposed in and extending outwards from the driven member body portion. At least one of the bearings may be configured to engage a groove or slot formed or otherwise provided in the driven member housing. In particular embodiments, at least one on the bearings may comprise or take the form of a ball bearing, e.g. a steel ball bearing. Alternatively, at least one on the bearings may comprise or take the form of a roller bearing. The shaft of the driven member may be configured to receive one or more magnetic elements. The one or more magnetic elements of the shaft may be configured and / or operable to co-operate with one or more magnetic elements of the drive member, in particular the inner arrangement provided on the distal end face of the drive member. In use, rotation of the drive member about its axis of rotation causes the magnetic elements of the inner arrangement to process around the axis of rotation, thereby exposing the magnetic elements of the shaft of the driven member to a repelling force (where exposed to a magnetic element of the same polarity) or an attractive force (where exposed to a magnetic element of the opposing polarity). This linear, e.g. oscillatory, movement of the driven member body portion and of the shaft, as well as the rotational movement of the shaft, causes the associated tool head of the power tool to move linearly, e.g. oscillate, and rotationally. Beneficially, such an arrangement may be used to provide an impact driver or hammer drill functionality. The shaft may comprise a plurality of magnetic elements disposed thereon, the plurality of magnetic elements comprising at least one first magnetic element of a first polarity and at least one second magnetic element of a second, opposing, polarity. In particular embodiments, the magnetic elements may be arranged so that the polarity of the magnetic elements alternates. More particularly, but not exclusively, the magnetic elements may be arranged so that the polarity of successive magnetic elements alternates, e.g. north pole, south pole, north pole, etc. However, it will be understood that other arrangements may be provided, e.g. north pole, north pole, south pole, south pole, north pole, north pole etc. The magnetic elements may be circumferentially arranged and / or spaced. The magnetic elements may be arranged in one or more rows., e.g. concentric rows. At least one of the magnetic elements may comprise or take the form of a permanent magnet. In particular embodiments, at least one of the magnetic elements may comprise or take the form of a neodymium magnet. Alternatively or additionally, at least one of the magnetic elements may comprise or take the form of: a samarium-cobolt magnet; an alnico magnet; or any other suitable permanent magnet. Alternatively or additionally, at least one of the magnetic elements may comprise or take the form of an electromagnet. The shaft may comprise one or more recesses, e.g. pockets or apertures, for receiving the magnetic elements. Each recess may receive a single magnetic element or a plurality of the magnetic elements. The recesses may be formed or otherwise provided in the shaft. In particular, the recesses may be provided in a proximal end surface of the shaft. The one or more recesses may be configured, e.g. dimensioned, shaped or otherwise constructed, to receive the magnetic elements. At least one of the recesses may be cylindrical or substantially cylindrical. However, it will be understood that the recesses may take any suitable cross-sectional form, e.g. rectangular or substantially rectangular, segment-shaped or the like. In particular embodiments, the shaft may comprise a plurality of the recesses. The recesses may be circumferentially arranged and / or spaced. Each recess may receive a single magnetic element or a plurality of the magnetic elements. The recesses may be arranged in one or more rows, e.g. concentric rows. Alternatively, the driven member body portion may comprise a single recess for receiving the plurality of magnetic elements. Alternatively, the magnetic elements may be secured to the shaft. For example, the magnetic elements may be secured to the shaft by a coupling arrangement, e.g. one or more mechanical fasteners, adhesive bond, or other suitable coupling. The transmission arrangement may comprise a damping arrangement. The damping arrangement may comprise or take the form of a mechanical damping arrangement, e.g. a spring, a rubber component or a dashpot. In particular embodiments, the damping arrangement may comprise or take the form of a magnetic damping arrangement. The damping arrangement may comprise a rear damping arrangement. In use, the rear damping arrangement may prevent or at least resist the physical engagement between the driven member and the drive member. Beneficially, the transmission arrangement may thus obviate or at least mitigate the wear associated with conventional tools and equipment. This, in turn, may facilitate prolonged operational lifetime and / or increased utility due e.g. to reduced need for repair, maintenance and replacement of the transmission arrangement. Moreover, the transmission arrangement permits the drive member and associated components to be physically isolated from the driven member and associated components. The rear damping arrangement may be at least partially formed by the magnetic elements of the drive member and the driven member having the same polarity. As described above, rotation of the drive member about its axis of rotation causes the magnetic elements disposed thereon to process around the axis of rotation, thereby periodically exposing the magnetic elements of the driven member to a repelling force (where exposed to a magnetic element of the same polarity). This periodic repelling may form or form part of the rear damping arrangement. The damping force may be tuned, e.g. by the arrangement of the magnetic elements. Alternatively or additionally, the rear damping arrangement may comprise one or more further magnetic elements of the same polarity. The rear damping arrangement may comprise at least one further magnetic element disposed on the drive member and at least one further magnetic element disposed on the driven member. The at least one further magnetic element disposed on the drive member may be aligned with the rotational axis of the drive member. The at least one further magnetic element disposed on the driven member may be aligned with a central axis of the driven member. The positioning of the one or more further magnetic elements may be configured and / or operable to provide a constant and / or non-variable repelling force between the drive member and the driven member when the magnetic fields of the further magnetic elements interact. The at least one further magnetic element disposed on the drive member may be disposed on or in a boss portion of the drive member body portion. The boss portion may extend from the drive member body portion towards the driven member. Alternatively or additionally, the at least one further magnetic element disposed on the driven member may be disposed on or in a recess portion of the driven member body portion. At least one of the further magnetic elements may comprise or take the form of a permanent magnet. At least one of the further magnetic elements may comprise or take the form of a neodymium magnet. Alternatively or additionally, at least one of the further magnetic elements may comprise or take the form of: a samarium-cobolt magnet; an alnico magnet; or any other suitable permanent magnet. Alternatively, at least one of the further magnetic elements may comprise or take the form of an electromagnet. The rear damping arrangement may reduce the rotational speed at which the transmission arrangement begins to operate. The magnetic transmission arrangement may comprise a front damping arrangement. In use, the front damping arrangement may prevent or at least resist the physical engagement between the driven member and the driven member housing. Beneficially, the damping arrangement may thus obviate or at least mitigate the wear associated with conventional tools and equipment. This, in turn, may facilitate prolonged operational lifetime and / or increased utility due e.g. to reduced need for repair, maintenance and replacement of the transmission arrangement The front damping arrangement may comprise or take the form of a magnetic damping arrangement. The front damping arrangement may comprise one or more magnetic elements. The front damping arrangement may comprise at least one magnetic element disposed on or in the driven member and at least one magnetic element disposed on or in the driven member housing. The at least one magnetic element disposed on or in the driven member and at least one magnetic element disposed on or in the driven member housing may be of the same polarity. In particular embodiments, the driven member body portion may comprise one or more recesses, e.g. pockets or apertures, for receiving the magnetic elements of the front damping arrangement. The recesses may be formed in the driven member body portion. In particular, the recesses may be provided in the outer surface of the driven member body portion. The one or more recesses may be configured, e.g. dimensioned, shaped or otherwise constructed, to receive the magnetic elements. At least one of the recesses may be cylindrical or substantially cylindrical. In particular embodiments, the driven member body portion may comprise a plurality of the recesses. The recesses may be circumferentially arranged and / or spaced. Each recess may receive a single magnetic element or a plurality of the magnetic elements. Alternatively, the driven member body portion may comprise a single recess for receiving the plurality of magnetic elements. Alternatively, the magnetic elements may be secured to the driven member body portion. For example, the magnetic elements may be secured to the driven member body portion by a coupling arrangement, e.g. one or more mechanical fasteners, adhesive bond, or other suitable coupling. In particular embodiments, the driven member housing may comprise one or more recesses, e.g. pockets or apertures, for receiving the magnetic elements of the front damping arrangement. The recesses may be formed in the driven member housing. In particular, the recesses may be provided in the inner, e.g. proximal, surface of the driven member housing. The one or more recesses may be configured, e.g. dimensioned, shaped or otherwise constructed, to receive the magnetic elements. At least one of the recesses may be cylindrical or substantially cylindrical. In particular embodiments, the driven member housing may comprise a plurality of the recesses. The recesses may be circumferentially arranged and / or spaced. Each recess may receive a single magnetic element or a plurality of the magnetic elements. Alternatively, the driven member housing may comprise a single recess for receiving the plurality of magnetic elements. Alternatively, the magnetic elements may be secured to the driven member housing. For example, the magnetic elements may be secured to the driven member housing by a coupling arrangement, e.g. one or more mechanical fasteners, adhesive bond, or other suitable coupling. At least one of the one or more magnetic elements may comprise or take the form of a permanent magnet. In particular embodiments, the at least one magnetic elements may comprise or take the form of a neodymium magnet. Alternatively or additionally, at least one of the magnetic elements may comprise or take the form of: a samarium-cobolt magnet; an alnico magnet; or any other suitable permanent magnet. Alternatively or additionally, at least one of the magnetic elements may comprise or take the form of an electromagnet. As described above, the driven member comprises one or more magnetic elements disposed thereon. The magnetic elements of the damping arrangement may be configured so as to optimise the acceleration of the driven member. The magnetic elements of the damping arrangement may be positioned so as to optimise the acceleration of the driven member. The strength of the magnetic elements of the damping arrangements may be reduced so as to optimise the acceleration of the driven member. The thickness of the magnetic elements of the damping arrangement may be reduced so as to optimise the acceleration of the driven member. The thickness of the magnetic elements of the rear damping arrangement may be reduced so as to optimise the acceleration of the driven member. Beneficially, the reduction in thickness of the magnetic elements of the rear damping arrangement ensures that said magnetic elements only become effective when the driven member body portion is in close proximity to the drive member body portion. Thus, the detrimental effects of the first damping arrangement on the acceleration of the driven member may be reduced. In some embodiments, the transmission arrangement may be provided without the front damping arrangement. Beneficially, this may reduce the energy required in order to cause the maximum linear displacement of the driven member (and associated tool head). In other words, the initial operation of the tool requires less energy. Furthermore, as the operation of the tool begins, and the user brings the tool head into engagement with a workpiece, e.g. a marine growth to be removed, the engagement of the tool head with the workpiece, e.g. a marine growth, overcomes the initial biasing of the driven member, and forces the driven member towards the drive member. The increased force required to bias the driven member towards the drive member by the user produces a correspondingly increased force of repulsion to be exerted by the drive member on the driven member, thus increasing the linear acceleration of the driven member, and thus the force with which the tool head is capable of removing marine growths. In other words, the efficiency of the marine growth removal tool is increased. The transmission arrangement may comprise one or more members configured and / or operable to block magnetic flux. The transmission arrangement may comprise a plurality of members configured and / or operable to block magnetic flux. In use, at least one of the members may be positioned such that the effects of any magnetic field produced within the transmission arrangement are directed away from the rotary drive arrangement. Beneficially, at least one of the members prevents the interaction of any magnetic fields produced within the transmission arrangement with the components of the rotary drive arrangement. As such, any potentially detrimental effects stemming from the magnetisation of the rotary drive arrangement are prevented. Moreover, the one or more members may increase the force of repulsion and / or attraction exerted by the drive member on the driven member, thereby increasing the linear acceleration and / or associated force exerted by the driven member and associated tool head. At least one of the members may be interposed between the drive member and the rotary drive arrangement. At least one of the members may be interposed between the driven member and associated tool head. In particular embodiments, at least one of the members may comprise or take the form a plate (“magnetic flux plate”). At least one of the members may be partially or wholly constructed from a metal, in particular a ferromagnetic metal such as steel. The transmission arrangement may be configured and / or operable so that the acceleration of and / or associated force exerted by the driven member can be varied. For example, this may be achieved by changing the number of magnetic elements of the transmission arrangement, a greater number of magnetic elements facilitating movement of the driven member with higher acceleration and / or exerting greater force. The transmission arrangement may thus be configurable so as to form a force multiplier. Beneficially, this may increase the operational effectiveness of the associated tool. For example, when the tool comprises or takes the form of a marine growth removal tool the effectiveness of marine growth removal may be enhanced. The transmission arrangement may comprise one or more slip bearings. At least one slip bearing of the transmission arrangement may be located at the interface between the outer surface of the drive member and the inner surface of the driven member. At least one of the slip bearings may be coupled to and / or operatively associated with the outer surface of the drive member. At least one of the slip bearing may be coupled to and / or operatively associated with the inner surface of the driven member. Alternatively, or additionally, the inner surface of the drive member and / or the driven member may comprise a coating. The coating may comprise or take the form of a lubricant. In use, the provision of slip bearings and / or lubricants at the interface between the drive member and the driven members reduces the rotational speed at which the transmission arrangement begins to operate. The transmission arrangement may comprise a biasing arrangement. The biasing arrangement may be configured and / or operable to bias the driven member towards the drive member. Alternatively, the biasing arrangement may be configured and / or operable to bias the driven member towards the drive member. The biasing arrangement may comprise a spring. In use, rotation of the drive member about its axis of rotation causes the one or more magnetic elements disposed thereon to process around the axis of rotation, thereby exposing the one or more magnetic elements of the driven member to either a repelling force (where exposed to a magnetic element of the drive member of the same polarity) or an attractive force (where exposed to a magnetic element of the drive member of the opposing polarity). In some embodiments, the one or more magnetic elements of the drive member and the one or more magnetic elements of the driven arrangement may be configured so that the rotation of the drive member causes a unidirectional force, e.g. a repulsive force only or an attractive force only. This may be case e.g. where the one or more magnetic elements on the drive member are all of the same polarity and the one or more magnetic elements on the driven member are all of the same polarity. Where the polarity of the one or more magnetic elements on the driven member are the same polarity as the one or more magnetic elements on the drive member, the driven member may be subject to a uni-directional repulsive force. Where the polarity of the one or more magnetic elements on the driven member is different to the one or more magnetic elements on the drive member, the driven member may be subject to a uni-directional attractive force. In such embodiments, the biasing arrangement may provide a force on the driven member opposing that of the magnetically-induced force generated by the transmission arrangement, this facilitating the oscillatory movement of the driven member. According to a second aspect, there is provided a power tool comprising the magnetic transmission arrangement of the first aspect. In particular embodiments, the tool may comprise or take the form of a marine growth removal tool. The tool may comprise a rotary drive arrangement. The rotary drive arrangement may comprise a motor. The motor may comprise or take the form of an electric motor. The motor may comprise or take the form of a direct current (DC) electric motor. The motor may comprise or take the form of a hydraulic motor. The motor may comprise or take the form of a pneumatic motor. The tool may comprise a housing. The housing may comprise, may be coupled to and / or operatively associated with a handle. The housing may be modular. The drive member housing may form part of the housing. The driven member housing may form part of the housing. The drive member housing may be coupled to and / or operatively associated with the driven member housing. The drive member housing may be removably coupled to and / or operatively associated with the driven member housing. Alternatively, or additionally, the drive member housing and the driven member housing may form a unitary construction. The drive member housing may comprise a female connector. The drive member housing and the female connector may form a unitary construction. Alternatively, or additionally, the female connector may be coupled to and / or operatively associated with the drive member housing. The female connector of the drive member housing may be configured to receive the male connector of the driven member housing therein. The driven member housing may be removably coupled to the drive member housing via a snap fit connection. In use, the female connector of the drive member housing receives the male connector of the driven member housing therein. Due to the reliance of the transmission arrangement of the apparatus on magnetism, the use of mechanical components in order to connect the drive and the driven members of the transmission arrangement is unnecessary. As such, the interface between the drive member and the driven member may take the form of a void, free of any mechanical components required to link the transmission arrangement together. Beneficially, the absence of any obstructive mechanical components at the interface between the drive member and the driven member allows for the drive member - as well as the rotary drive arrangement to which it is removably connected within the drive member housing - to be sealed from the driven member. Where the tool is used as a marine growth removal tool, the isolation of the drive member from the driven member increases the durability of the tool by increasing the resistivity of the tool to the marine environment. The tool may comprise, may be coupled to and / or operatively associated with a power supply. The power supply may be configured and / or operable to power the rotary drive arrangement. In particular embodiments, the power supply may comprise or take the form of an onboard power supply, e.g. a battery. Beneficially, the provision of a portable power supply such as a battery obviates or at least mitigates the need for restrictive umbilical arrangements, and the associated drawbacks discussed above. Alternatively or additionally, the power supply may comprise a fluid power supply, such as a hydraulic power supply or pneumatic power supply. The tool may comprise, may be configured for coupled to and / or operatively associated with a tool head. The tool head may be fixedly coupled to the tool. Alternatively, the tool head may be removably couplable to the tool. The tool head may take a variety of different forms. In particular embodiments, the tool head may comprise or take the form of a scraper. Alternatively or additionally, the tool head may comprise or take the form of a blade, e.g. a saw blade. Alternatively or additionally, the tool head may comprise or take the form of a brush. According to a third aspect, there is provided a tool system comprising one or more tools according to the second aspect. The system may comprise a subsea tool system. The system may further comprise a remotely operated vehicle (ROV), e.g. an observational class ROV. In use, marine growths are removable from the subsea surface of a marine structure or vessel via the operation of the ROV to which the tool may be mounted. Beneficially, the operation of the above discussed system removes any reliance on human operators, e.g. divers, to remove marine growths from the subsea surface of a marine structure or vessel. In doing so, it becomes unnecessary for divers to enter into deep, complex subsea environments, and thus reduces the health and safety risks to which the diver is exposed. Furthermore, having mounted the cleaning apparatus to the ROV, the ROV is capable of conducting both the visual assessment and subsequent cleaning of a marine structure or vessel, reducing the downtime between visual assessment and the deployment of conventional cleaning means. As such, the effectiveness of the system is increased, increasing the levels of marine growth it is possible to remove from the marine structure or vessel in question. In reducing the time taken to undertake marine growth removal, the operation of such a system increases the efficiency of any inspection or decommissioning processes, for example, executable only once any obstructive marine growths have been removed. The mounting of the cleaning apparatus to the ROV also enables marine growth removal to be carried out at greater subsea depths than are accessible by human operators employing conventional cleaning means. According to a fourth aspect, there is provided a method for marine growth removal using of the tool of the second aspect or the system of the third aspect. According to a fifth aspect, there is provided a magnetic damping arrangement for a power tool such as a marine growth removal tool. The magnetic damping arrangement may comprise a rear magnetic damping arrangement, as described above. The magnetic damping arrangement may comprise a front magnetic damping arrangement, as described above. According to a sixth aspect, there is provided a power tool comprising the magnetic damping arrangement of the fifth aspect. According to a seventh aspect, there is provided a tool system comprising one or more tools according to the sixth aspect. According to an eighth aspect, there is provided a method for marine growth removal using of the magnetic damping arrangement of the fifth aspect, the tool of the sixth aspect or the tool system of the seventh aspect. According to a ninth aspect, there is provided a magnetic transmission arrangement comprising: a drive member configured for coupling to, forming part of or operatively associated with a rotary drive arrangement, wherein the drive member comprises one or more magnetic elements disposed thereon; and a driven member, wherein the driven member comprises one or more magnetic elements disposed thereon, wherein the driven member is spaced from the drive member, and wherein the magnetic transmission arrangement is configured to convert rotation of the drive member by the rotary drive arrangement into linear movement of the driven member. The invention is defined by the appended claims. However, for the purposes of the present disclosure it will be understood that any of the features defined above or described below may be utilised in isolation or in combination. For example, features described above in relation to one of the above aspects or below in relation to the detailed description below may be utilised in any other aspect, or together form a new aspect. BRIEF DESCRIPTION OF THE DRAWINGS These and other aspects will now be described with reference to the accompanying drawings, in which: Figure 1 shows an exploded perspective view of a magnetic transmission arrangement, shown disposed in a power tool; Figure 2 shows another view of the magnetic transmission arrangement shown in Figure 1; Figure 3 shows another view of the magnetic transmission arrangement shown in Figure 1; Figure 4 shows a front perspective view of a drive member of the magnetic transmission arrangement shown in Figure 1; Figure 5 shows a rear perspective view of the drive member of the magnetic transmission arrangement shown in Figure 1; Figures 6 shows a rear perspective view of the driven member of the magnetic transmission arrangement shown in Figure 1, shown disposed in a tool head of the power tool; Figure 7 shows another rear perspective view of the driven member of the magnetic transmission arrangement shown in Figure 1; Figure 8 shows a front perspective and cutaway view of the driven member of the magnetic transmission arrangement shown in Figure 1; Figure 9 shows another cutaway view of the driven member of the magnetic transmission arrangement shown in Figure 1, showing a rotational lock; Figures 10 to 12 show a power tool comprising the transmission arrangement shown in Figure 1; Figure 13 shows a tool system comprising the tool shown in Figures 10 to 12; Figure 14 shows alternative tool bits for the tool head; Figure 15 shows an alternative power tool comprising one or more handles; Figure 16 shows an alternative power tool comprising one or handles and a support arrangement; Figure 17 shows an alternative power tool comprising one or more handles, a support arrangement and a remote power supply; Figure 18 shows an alternative power tool comprising one or more handles and a remote power supply; Figure 19 shows an alternative power tool comprising a remote power supply; Figure 20 shows an alternative power tool comprising one or more handles and a remote power supply; Figure 21 shows an alternative magnetic transmission arrangement; Figure 22 shows a perspective view of an alternative magnetic transmission arrangement comprising a hexagonal or substantially hexagonal driven member body portion and a hexagonal or substantially hexagonal driven member housing; Figure 23 shows a perspective view of an alternative magnetic transmission arrangement comprising a rectangular or substantially rectangular shaft of the driven member and a rectangular or substantially rectangular channel formed through the driven member housing; Figure 24 shows a perspective view of an alternative power tool comprising a driven member wherein a shaft of the driven member is rotationally coupled to a driven member body portion; Figure 25 shows an exploded view of the alternative power tool shown in Figure 24; and Figures 26 and 27 show an alternative transmission arrangement. DETAILED DESCRIPTION OF THE DRAWINGS Referring first to Figures 1 to 3 of the accompanying drawings, there is shown a magnetic transmission arrangement 10 for a power tool 100 (shown in Figure 1) such as a powered marine growth removal tool. As shown, the magnetic transmission arrangement 10 comprises a drive member, generally denoted 12, and a driven member, generally denoted 14. The drive member 12 is configured for coupling to, forming part of or operatively associated with a rotary drive arrangement 102 of the power tool 100 and comprises magnetic elements 16N of a first polarity and magnetic elements 16S of a second, opposing, polarity. The driven member 14 is configured for coupling to, forming part of or operatively associated with a tool head 104 of the power tool 100 and comprises magnetic elements 18N of said first polarity and magnetic elements 18S of said second, opposing, polarity. As will be described further below, the magnetic transmission arrangement 10 is configured to convert rotation of the drive member 12 by the rotary drive arrangement 102 into linear - in particular oscillatory - movement of the driven member 14. In use, rotation of the drive member 12 about its axis of rotation A causes the magnetic elements 16N,16S disposed thereon to process around the axis of rotation A, thereby exposing the magnetic elements 18N,18S of the driven member 14 to a repelling force (where exposed to a magnetic element of the same polarity) or an attractive force (where exposed to a magnetic element of the opposing polarity). This linear, e.g. oscillatory, movement of the driven member 14 causes the associated tool head 104 of the power tool 100 to move linearly, e.g. oscillate. The illustrated power tool 100 comprise or take the form of a powered marine growth removal tool, and said linear, e.g. oscillatory, movement of the driven member 14 causes the associated tool head 104 of the marine growth removal tool to move linearly, e.g. oscillate, thereby facilitating removal of marine growth from a marine structure or vessel (not shown). However, it will be understood that the magnetic transmission arrangement 10 may be utilised in a wide variety of tools and / or applications. Beneficially, the present transmission arrangement 10 facilitates the conversion of a rotary input into a linear, e.g. oscillatory, output, without relying on the physical interaction between the drive member 12 and driven member 14. Amongst other things, the transmission arrangement 10 thus obviates or at least mitigate the wear associated with conventional tools and equipment. This, in turn, may facilitate prolonged operational lifetime and / or increased utility due e.g. to reduced need for repair, maintenance and replacement of the transmission arrangement 10. Moreover, the transmission arrangement 10 permits the drive member 12 and associated components to be physically isolated from the driven member 14 and associated components. The present transmission arrangement 10 is particularly beneficial for tools and / or applications utilised in harsh and / or remote environments, such as the marine environment. For example, the illustrated transmission arrangement 10 is utilised as part of a marine growth removal tool, the transmission arrangement 10 facilitates the conversion of a rotary input into a linear, e.g. oscillatory, output which provides for the highly effective removal of marine growth. Moreover, the transmission arrangement 10 may obviate or at least mitigate the wear associated with conventional marine growth removal tools and equipment, facilitating prolonged operational lifetime and / or increased utility due e.g. to reduced need for repair, maintenance and replacement of the transmission arrangement 10. This may facilitate an increase in the amount of marine growth that can be removed during a given operation and thus reduce overall time that operatives, e.g. divers, are exposed to the harsh marine environment. The transmission arrangement 10 may alternatively or additionally obviate or reduced the need for umbilical arrangements that are intrinsically large and cumbersome and can be restrictive to diver movement underwater, otherwise limiting utility and leading to potential health and safety risks. The above benefits may in turn reduce the risk of corrosion of metal components provided on or forming part (often a structurally critical part) of marine structures or vessels and / or reduce the likelihood that damage may go unidentified and remedied. As described above, the magnetic transmission arrangement 10 comprises a drive member 12 configured for coupling to, forming part of or operatively associated with a rotary drive arrangement 102 of the power tool 100. Referring now also to Figures 4 and 5 of the accompanying drawings, which show enlarged perspective views of the drive member 12, it can be seen that the drive member 12 comprises a body portion (“drive member body portion”) 20. In the illustrated transmission arrangement 10, the drive member body portion 20 is directly or coupled to a drive shaft 106 of the rotary drive arrangement 102. In the illustrated transmission arrangement 10, the drive member body portion 20 is cylindrical or substantially cylindrical in shape and comprises an inner surface 22 which, in use, defines a proximal surface (i.e. closer to the rotary drive arrangement 102) of the drive member 12 and an outer surface 24 which, in use, defines a distal surface (i.e. further from to the rotary drive arrangement 102) of the drive member 12. The outer, distal, surface 24 is orientated to face the driven member 12. As described above, the drive member 12 comprises a plurality of magnetic elements 16N.16S disposed thereon. In the illustrated transmission arrangement 10 the drive member body portion 20 comprises recesses 26 for receiving the magnetic elements 16N, 16S, the recesses 26 being provided in the outer surface 24 of the drive member body portion 20. The recesses 26 are circumferentially arranged and / or spaced. The recesses 26 are configured, e.g. dimensioned, shaped or otherwise constructed, to receive the magnetic elements 16N, 16S. In the illustrated transmission arrangement 10, the recesses 26 are cylindrical or substantially cylindrical in shape. As described above, the drive member 12 comprises a plurality of magnetic elements 16N of the first polarity and a plurality of magnetic elements 16S of the second, opposing, polarity. In the illustrated transmission arrangement 10, the magnetic elements 16N, 16S arranged so that the polarity of successive magnetic elements 16N, 16S alternates, i.e. north pole, south pole, north pole, etc. However, it will be understood that other arrangements may be provided, e.g. north pole, north pole, south pole, south pole, north pole, north pole etc. In the illustrated transmission arrangement 10, the magnetic elements 16N, 16S take the form of neodymium magnets. As shown, the transmission arrangement 10 comprises a housing 28 (“drive member housing”) for receiving the drive member 12. In the illustrated transmission arrangement 10, the drive member housing 28 is cylindrical or substantially cylindrical. As described above, the magnetic transmission arrangement 10 comprises a driven member 14 configured for coupling to, forming part of or operatively associated with a tool head 104 of the power tool 100. Referring now also to Figures 6, 7 and 8 of the accompanying drawings, which show enlarged perspective views of the driven member 14, it can be seen that the driven member 14 comprises a body portion (“driven member body portion”) 30. In the illustrated transmission arrangement 10, the driven member body portion 30 is directly coupled, to the tool head 104. In the illustrated transmission arrangement 10, the driven member body portion 30 is cylindrical or substantially cylindrical and comprise an inner surface 32 which, in use, defines a proximal surface (i.e. closer to the drive member 12) of the driven member 14 which is orientated towards the drive member 12 and an outer surface 34 which, in use, defines a distal surface (i.e. further from the drive member 12) of the driven member 14 and which is orientated towards the tool head 104. As shown, the driven member 14 comprises a shaft 36. The shaft 36 is aligned or substantially aligned with a central axis B of the driven member 14, more particularly the driven member body portion 30, and in the illustrated transmission arrangement 10 is co-linear with the axis of rotation A of the drive member 12. In use, the shaft 36 transmits the linear, e.g. oscillatory, movement of the driven member 14 to the tool head 104. In the illustrated transmission arrangement 10, the shaft 36 forms part of the driven member body portion 30 and is hollow in construction. However, it will be understood that the shaft 36 may alternatively take the form of a separate component coupled to the driven member body portion 30. As described above, the driven member 14 comprises a plurality of magnetic elements 18N, 18S disposed thereon. In the illustrated transmission arrangement 10, the driven member body portion 30 comprises recesses 38 for receiving the magnetic elements 18N, 18S. The recesses 38 are circumferentially arranged and / or spaced. The recesses 38 are formed in the driven member body portion 30, more particularly the inner surface 32 of the driven member body portion 30. The recesses 38 are configured, e.g. dimensioned, shaped or otherwise constructed, to receive the magnetic elements 18N, 18S. In the illustrated transmission arrangement 10, the recesses 38 are cylindrical or substantially cylindrical. As described above, the driven member 14 comprises a plurality of magnetic elements 18N of the first polarity and a plurality of magnetic elements 18S of the second, opposing, polarity. In the illustrated transmission arrangement 10, the magnetic elements 18N, 18S are arranged so that the polarity of successive magnetic elements 18N, 18S alternates, i.e. north pole, south pole, north pole, etc. However, it will be understood that other arrangements may be provided, e.g. north pole, north pole, south pole, south pole, north pole, north pole etc. In the illustrated transmission arrangement 10, the magnetic elements 18N, 18S take the form of neodymium magnets. The transmission arrangement 10 comprises a housing (“driven member housing”) 40 for receiving the driven member 14. In the illustrated transmission arrangement 10, the driven member housing 40 is cylindrical or substantially cylindrical in shape. The transmission arrangement 10 is configured and / or operable to convert rotation of the drive member 12 into solely linear, e.g. oscillatory, motion or substantially solely linear motion of the driven member 14. The transmission arrangement 10 comprises an arrangement for preventing or substantially preventing rotation of the driven member, generally denoted 42. In the illustrated transmission arrangement 10, the arrangement 42 comprises or takes the form of a rotational lock for preventing or substantially preventing rotation of the driven member 14. As shown most clearly in Figure 9 of the accompanying drawings, arrangement 42 comprises elongate protrusions 44. The protrusions extend radially outwardly from the driven member body portion 30. In the illustrated transmission arrangement 10, the protrusions 44 form part of the driven member body portion 30. However, it will be understood that the protrusions 44 may alternatively take the form of separate components coupled to the driven member body portion 30. As shown, the protrusions 44 are each configured to engage a respective groove 46 formed or otherwise provided in the driven member housing 40. Beneficially, the arrangement 42 may permit linear, e.g. oscillatory, movement of the driven member 14 in response to rotation of the drive member 12 but prevent or substantially prevent rotation of the driven member 14. As shown most clearly in Figure 2 of the accompanying drawings, the transmission arrangement 10 comprises a magnetic damping arrangement, generally denoted 48, which in the illustrated transmission arrangement comprises a rear damping arrangement, generally denoted 50, and a front damping arrangement, generally denoted 52. In use, the rear damping arrangement 50 prevents or at least resists the physical engagement between the drive member 12 and the driven member 14. Beneficially, the damping arrangement 10 may thus obviate or at least mitigate the wear associated with conventional tools and equipment. This, in turn, may facilitate prolonged operational lifetime and / or increased utility due e.g. to reduced need for repair, maintenance and replacement of the transmission arrangement 10. The rear damping arrangement 50 is partially formed by the magnetic elements 16N, 16S, 18N, 18S of the drive member 12 and the driven member 14 having the same polarity. As described above, rotation of the drive member 12 about its axis of rotation A causes the magnetic elements 16N, 16S disposed thereon to process around the axis of rotation A, thereby periodically exposing the magnetic elements 18N, 18S of the driven member 14 to a repelling force (where exposed to a magnetic element of the same polarity). This periodic repelling may form or form part of the rear damping arrangement 50. The illustrated rear damping arrangement 50 further comprises a further magnetic element 54S disposed on the drive member 12 and a further magnetic element 56S disposed on the driven member 14, the further magnetic elements 54S, 56S being of the same polarity. The positioning of the further magnetic elements 54S, 56S are configured and / or operable to provide a constant and / or non-variable repelling force between the drive member 12 and the driven member 14 when the magnetic fields of the further magnetic elements 54S, 56S interact. As shown, the further magnetic element 54S disposed on the drive member 12 is disposed on or in a boss portion 58 of the drive member body portion 20. The boss portion 58 extends from the drive member body portion 20 towards the driven member 14. The further magnetic element 56S disposed on the driven member 14 is disposed on or in a recess portion 60 of the driven member body portion 30. In the illustrated rear damping arrangement 50, the further magnetic elements 54S, 56S comprises or take the form of neodymium magnets. The rear damping arrangement 50 may reduce the rotational speed at which the transmission arrangement 10 begins to operate. As described above, the magnetic damping arrangement 48 comprises a front damping arrangement 52. In use, the front damping arrangement 52 prevents or at least resists the physical engagement between the driven member 12 and the driven member housing 40. Beneficially, the front damping arrangement 52 may thus obviate or at least mitigate the wear associated with conventional tools and equipment. This, in turn, may facilitate prolonged operational lifetime and / or increased utility due e.g. to reduced need for repair, maintenance and replacement of the transmission arrangement 10. The front damping arrangement 52 comprises magnetic elements 62S disposed on or in the driven member 14 and magnetic elements 64S disposed on or in the driven member housing 40. The magnetic elements 62S, 64S are of the same polarity. In the illustrated front damping arrangement 52, the magnetic elements 62S, 64S comprise or take the form of neodymium magnets. In the illustrated front damping arrangement 52, the driven member body portion 30 comprises recesses 66 for receiving the magnetic elements 62S. The recesses 66 are circumferentially arranged and / or spaced. The recesses 66 are configured e.g. dimensioned, shaped or otherwise constructed, to receive the magnetic elements 62S. The recesses 66 are cylindrical or substantially cylindrical. In the illustrated front damping arrangement 52, the driven member housing 40 comprises recesses 68 for receiving the magnetic elements 64S of the front damping arrangement 52. The recesses 68 are circumferentially arranged and / or spaced. The recesses 68 are configured e.g. dimensioned, shaped or otherwise constructed, to receive the magnetic elements 64S. The recesses 68 are cylindrical or substantially cylindrical. The recesses 68 are circumferentially arranged and / or spaced. The recesses 68 are configured e.g. dimensioned, shaped or otherwise constructed, to receive the magnetic elements 64S. The recesses 68 are cylindrical or substantially cylindrical. In the illustrated front damping arrangement 52, the magnetic elements 64S, 64S comprise or take the form of neodymium magnets. In some embodiments, the transmission arrangement 10 may be provided without the front damping arrangement 52. Beneficially, this may reduce the energy required in order to cause the maximum linear displacement of the driven member 14 (and associated tool head 104). In other words, the initial operation of the tool 100 requires less energy. Furthermore, as the operation of the tool 100 begins, and the user brings the tool head 104 into engagement with a workpiece, e.g. a marine growth to be removed, the engagement of the tool head 104 with the workpiece, e.g. a marine growth, overcomes the initial biasing of the driven member 14, and forces the driven member 14 towards the drive member 12. The increased force required to bias the driven member 14 towards the drive member 12 by the user produces a correspondingly increased force of repulsion to be exerted by the drive member 12 on the driven member 14, thus increasing the linear acceleration of the driven member 14, and thus the force with which the tool head 104 is capable of removing marine growths. In other words, the efficiency of the marine growth removal tool is increased. As shown most clearly in Figures 3 to 5 of the accompanying drawings, the transmission arrangement 10 comprises a plurality of members 70a, 70b configured and / or operable to block magnetic flux and / or increase the force of repulsion and / or attraction exerted by the drive member 12 on the driven member 14. In use, the member 70a is positioned such that the effects of any magnetic field produced within the transmission arrangement 10 are directed away from the rotary drive arrangement 102. Beneficially, the member 70a prevents the interaction of any magnetic fields produced within the transmission arrangement 10 with the components of the rotary drive arrangement 102. As such, any potentially detrimental effects stemming from the magnetisation of the rotary drive arrangement 102 are prevented. Moreover, the members 70a, 70b may increase the force of repulsion and / or attraction exerted by the drive member 12 on the driven member 14, thereby increasing the linear acceleration and / or associated force exerted by the driven member 14 and associated tool head 104. As shown, the member 70a is interposed between the drive member 12 and the rotary drive arrangement 102 and in the illustrated transmission arrangement 10 comprises or takes the form a steel plate (“magnetic flux plate”). As described above, in use, rotation of the drive member 12 about its axis of rotation A causes the magnetic elements 16N, 16S disposed thereon to process around the axis of rotation A, thereby exposing the magnetic elements 18N, 18S of the driven member 14 to a repelling force (where exposed to a magnetic element of the same polarity) or an attractive force (where exposed to a magnetic element of the opposing polarity). This linear, e.g. oscillatory, movement of the driven member 14 causes the associated tool head 104 of the power tool 100 to move linearly, e.g. oscillate. The transmission arrangement 10 may be configured and / or operable so that the frequency of the oscillatory motion of the driven member 12 is variable. For example, the frequency may be variable by adapting the configuration of the magnetic elements 16n, 16S, 18N, 18S of the drive member 12 and / or driven member 14. The transmission arrangement 10 may be configured and / or operable so that the acceleration of and / or associated force exerted by the driven member 14 can be varied. For example, this may be achieved by changing the number of magnetic elements of the transmission arrangement 10, a greater number of magnetic elements facilitating movement of the driven member 14 with higher acceleration and / or exerting greater force. The transmission arrangement 10 may thus be configurable so as to form a force multiplier. Beneficially, this may increase the operational effectiveness of the associated tool 100. For example, when the tool 100 comprises or takes the form of a marine growth removal tool the effectiveness of marine growth removal may be enhanced. Figures 10, 11 and 12 of the accompanying drawings show the power tool 100, which as shown takes the form of a marine growth removal tool. As shown, the tool 100 comprises the transmission arrangement 10 described above and the rotary drive arrangement 102. In the illustrated tool 100, the rotary drive arrangement 102 comprises a motor, more specifically a direct current (DC) electric motor. As shown, the tool 100 comprises a housing, generally denoted 172. The drive member housing 28 of the housing 172 is configured to receive the drive member 12 of the transmission arrangement 10 therein. The drive member housing 28 is also configured to receive the rotary drive arrangement 102. Alternatively, the rotary drive arrangement 102 may be housed within a further housing portion. The driven member housing 40 is provided and is configured to receive the driven member 14 of the transmission arrangement 10 therein. The drive member housing 28 is coupled to and / or operatively associated with the driven member housing 40 so as to form the housing 172. In the illustrated tool 100, the drive member housing 28 is removably coupled to and / or operatively associated with the driven member housing 40. Beneficially, the absence of any obstructive mechanical components at the interface between the drive member 12 and the driven member 14 allows for the drive member 12 - as well as the rotary drive arrangement 102 to which it is removably connected within the drive member housing 28 - to be sealed from the driven member 14. Where the tool 100 is used as a marine growth removal tool, the isolation of the drive member 12 from the driven member 14 increases the durability of the tool 100 by increasing the resistivity of the tool 100 to the marine environment. The tool 100 further comprises a power supply 108. The power supply 108 is configured and / or operable to power the rotary drive arrangement 108. In the illustrated tool 100, the power supply 108 comprises or take the form of an onboard power supply, more particularly a battery. Beneficially, the provision of an onboard power supply such as a battery obviates or at least mitigates the need for restrictive umbilical arrangements, and the associated drawbacks discussed above. The tool 100 comprises, may be configured for coupled to and / or operatively associated with the tool head 104. The tool head 104 may take a variety of different forms. In the illustrated tool 100, the tool head 104 comprises or take the form of a scraper. Referring now also to Figure 13 of the accompanying drawings, the tool 100 may form part of a tool system, generally denoted S. As shown, the tool system S comprises a subsea tool system and comprises a remotely operated vehicle (ROV) S2, e.g. an observational class ROV. In use, marine growths are removable from the subsea surface of a marine structure or vessel via the operation of the ROV S2 to which the tool 100 is mounted. Beneficially, the operation of the above discussed system S removes any reliance on human operators, e.g. divers, to remove marine growths from the subsea surface of a marine structure or vessel. In doing so, it becomes unnecessary for divers to enter into deep, complex subsea environments, and thus reduces the health and safety risks to which the diver is exposed. Furthermore, having mounted the cleaning apparatus to the ROV S2, the ROV S2 is capable of conducting both the visual assessment and subsequent cleaning of a marine structure or vessel, reducing the downtime between visual assessment and the deployment of conventional cleaning means. As such, the effectiveness of the system S is increased, increasing the levels of marine growth it is possible to remove from the marine structure or vessel in question. In reducing the time taken to undertake marine growth removal, the operation of such a system S increases the efficiency of any inspection or decommissioning processes, for example, executable only once any obstructive marine growths have been removed. The mounting of the cleaning apparatus to the ROV S2 also enables marine growth removal to be carried out at greater subsea depths than are accessible by human operators employing conventional cleaning means. Various modifications may be made without departing from the scope of the invention as defined by the appended claims. For example, the arrangement 42, e.g. rotational lock, may comprise a bearing arrangement. As shown in Figure 14, the tool head 104 may alternatively comprise or take the form of a blade, e.g. a saw blade; a brush or other tool head. Whereas in the tool 100, the housing 172 forms the handle for use by the operator, Figure 15 shows an alternative tool 200 comprising one or more handles 274. Figure 16 shows an alternative tool 300 comprising a handle 374 and a support arrangement 376. As shown in Figure 17, an alternative tool 400 comprises a handle 474, a support arrangement 476 and a power supply 408, wherein the power supply 408 comprises or take the form of a remote power supply connected to the tool 400, more particularly a battery. As shown in Figure 18, an alternative tool 500 comprises one or more handles 574 and a power supply 508, wherein the power supply 508 comprises or take the form of a remote power supply connected to the tool 500, more particularly a battery. Figure 19 shows an alternative tool 600 comprising a power supply 608, wherein the power supply 608 comprises or take the form of a remote power supply connected to the tool 600, more particularly a battery Figure 20 shows an alternative tool 700 comprising a handle 774 and a power supply 708, wherein the power supply 708 comprises or take the form of a remote power supply connected to the tool 700, more particularly a battery An alternative magnetic transmission arrangement 810 is shown in Figure 21, of which the thickness and positioning of magnetic damping elements 816N, 816S, 818N, 818S of both the drive 812 and driven 814 members may be altered so as to ensure said magnetic damping elements 816N, 816S, 818N, 818S only become effective when the driven member body portion 830 is in close proximity to the drive member body portion 820. In doing so, any detrimental dampening effects on the acceleration of the driven member 814 may be reduced. An alternative magnetic transmission arrangement, generally denoted 910, is shown in Figure 22 of the accompanying drawings. As shown, a driven member body portion 930 takes the form of a hexagonal or substantially hexagonal body portion, body portion 930 having been received within a hexagonal or substantially hexagonal housing 940 and thus forming a rotational lock. It shall be understood that the transmission arrangement 910 is similar to the transmission arrangement 10, and that like components are referenced using like reference numerals, incremented by 900. An alternative magnetic transmission arrangement, generally denoted 1010, is shown in Figure 23. As shown, a shaft 1036 takes the form of a rectangular or substantially rectangular shaft, shaft 1036 having been received within a rectangular or substantially rectangular channel 1078 formed through a housing 1040 and thus forming a rotational lock. It shall be understood that the transmission arrangement 1010 is similar to the transmission arrangement 10, and that like components are referenced using like reference numerals, incremented by 1000. A perspective view of an alternative power tool, generally denoted 2100, comprising a driven member, generally denoted 2014, is shown in Figures 24 and 25. As shown, a shaft 2036 is rotationally coupled to a driven member body portion 2030, wherein magnetic elements 2018N, 2018S have been received within recesses 2080 provided in an inner surface 2082 of the shaft 2036. In the illustrated embodiment, the shaft 2036 of the driven member 2014 is directly coupled to a tool head, generally denoted 2104. In use, rotation of the drive member, generally denoted 2012, by the rotary drive arrangement, generally denoted 2102, is converted by the transmission arrangement, generally denoted 2010, into linear movement of the driven member body portion 2030 and the shaft 2036, in particular oscillatory movement of the driven member body portion 2030 and the shaft 2036, and rotational movement of the shaft 2036 of the driven member 2014. More particularly, rotation of the drive member 2012 about its axis of rotation causes the magnetic elements 2016N, 2016S of an inner arrangement, generally denoted 2084, disposed on an outer surface 2024 thereof to process around the axis of rotation, thereby exposing the magnetic elements 2018N, 2018S of the shaft 2036 of the driven member 2014 to a repelling force (where exposed to a magnetic element of the same polarity) or an attractive force (where exposed to a magnetic element of the opposing polarity). This linear, e.g. oscillatory, movement of the driven member body portion 2030 and of the shaft 2036, as well as the rotational movement of the shaft 2036, causes the associated tool head 2104 of the power tool 2100 to move linearly, e.g. oscillate, and rotationally, wherein the tool head 2104, for example, comprises an impact driver or a hammer drill. It shall be understood that the power tool 2100 is similar to the power tool 100, and that like components are referenced using like reference numerals, incremented by 2000. As described above, various modifications may be made without departing from the scope of the invention as defined by the appended claims. For example, Figures 26 and 27 of the accompanying drawings show a further alternative transmission arrangement 1110. As shown, the magnetic transmission arrangement 1110 comprises a drive member, generally denoted 1112, and a driven member, generally denoted 1114. The drive member 1112 comprises magnetic elements 1116N, all of a first polarity. The driven member 1114 comprises magnetic elements 1118N, all of said first polarity. As in the embodiments described above, the magnetic transmission arrangement 1110 is configured to convert rotation of the drive member 1112 into linear - in particular oscillatory - movement of the driven member 1114.

Claims

1. A magnetic transmission arrangement for a power tool such as a powered marine growth removal tool, the magnetic transmission arrangement comprising:5 a drive member configured for coupling to, forming part of or operativelyassociated with a rotary drive arrangement of the power tool,wherein the drive member comprises a one or more magnetic elements disposed thereon; anda driven member configured for coupling to, forming part of or operatively 10 associated with a tool head of the power tool,wherein the driven member comprises one or more magnetic elements disposed thereon,wherein the driven member is spaced from the drive member,and wherein the magnetic transmission arrangement is configured to convert15 rotation of the drive member by the rotary drive arrangement into linear movement of the driven member;wherein the transmission arrangement comprises a magnetic damping arrangement.20 2. The magnetic transmission arrangement of claim 1, wherein the magnetictransmission arrangement is configured to convert rotation of the drive member by the rotary drive arrangement into oscillatory movement of the driven member.

3. The magnetic transmission arrangement of claim 1 or 2, wherein at least one of 25 the drive member and the driven member comprises a plurality of the magnetic elements.

4. The magnetic transmission arrangement of claim 3, wherein at least one of:the plurality of magnetic elements on the drive member comprises at least one30 first magnetic element of a first polarity and at least one second magnetic element of a second, opposing, polarity;the plurality of magnetic elements on the driven member comprises at least one first magnetic element of the first polarity and at least one second magnetic element of the second, opposing, polarity.

5. The magnetic transmission arrangement of claim 4, wherein at least one of: the at least one first magnetic element of the drive member and the at least one second magnetic element of the drive member are circumferentially arranged in alternating fashion;5 the at least one first magnetic element of the driven member and the at leastone second magnetic element of the driven member are circumferentially arranged in alternating fashion.

6. The magnetic transmission arrangement of any preceding claim, wherein the10 drive member comprises a body portion.

7. The magnetic transmission arrangement of any preceding claim, wherein thedriven member comprises a body portion.

158. The magnetic transmission arrangement of any preceding claim, wherein the driven member is configured for location in a housing, and wherein the driven member is configured and / or operable to move linearly relative to the housing.

9. The magnetic transmission arrangement of any preceding claim, wherein the transmission arrangement is configured and / or operable to convert rotation of the drive member into solely linear motion or substantially solely linear motion of the driven member, the transmission arrangement comprising an arrangement for preventing or substantially preventing rotation of the driven member.25 10. The magnetic transmission arrangement of claim 9, wherein the arrangementfor preventing or substantially preventing rotation of the driven member relative to the drive member comprises a rotational lock.

11. The magnetic transmission arrangement of claim 9 or 10, when dependent on30 claim 8, wherein the arrangement for preventing or substantially preventing rotation of the driven member comprises at least one of:one or more protrusions configured to engage a groove or slot formed or otherwise provided in the housing;a bearing arrangement;a spline arrangement; anda cam and follower arrangement.

12. The magnetic transmission arrangement of any preceding claim, wherein the damping arrangement comprises a rear damping arrangement, the rear damping 5 arrangement configured and / or operable to prevent or at least resist the physical engagement between the driven member and the drive member.101513. The magnetic transmission arrangement of claim 12, wherein at least one of:the rear damping arrangement is at least partially formed by the magnetic elements of the drive member and the driven member having the same polarity;the rear damping arrangement comprises one or more further magnetic elements of the same polarity, at least one of said further magnetic elements being disposed on the drive member and at least one of said further magnetic elements being disposed on the driven member.

14. The magnetic transmission arrangement of claim 13, wherein at least one of:the at least one further magnetic element disposed on the drive member is aligned with the rotational axis of the drive member;the at least one further magnetic element disposed on the driven member is aligned with a central axis of the driven member.

15. The magnetic transmission arrangement of any one of claims 12 to 14, when dependent on claim 8, wherein the magnetic transmission arrangement comprises a front damping arrangement, the front damping arrangement configured and / or operable 25 to prevent or at least resist the physical engagement between the driven member and the housing.

16. The magnetic transmission arrangement of claim 15, wherein the front damping arrangement comprises at least one magnetic element disposed on or in the driven 30 member and at least one magnetic element disposed on or in the housing of the driven member, the at least one magnetic element disposed on or in the driven member and the at least one magnetic element disposed on or in the driven member housing being of the same polarity.5f17. The magnetic transmission arrangement of any one of claims 1 to 8, or claims 12 to 16 when dependent on any one of claims 1 to 8, wherein the magnetic transmission arrangement is configured to convert rotation of the drive member into linear and rotational movement of the driven member, the magnetic transmission 5 arrangement comprising an arrangement for converting rotation of the drive member by the rotary drive arrangement into linear and rotational movement of the driven member.

18. The magnetic transmission arrangement of claim 17, wherein the arrangement for converting rotation of the drive member by the rotary drive arrangement into linear 10 and rotational movement of the driven member comprises one or more magnetic elements provided on a shaft of the driven member, the one or more magnetic elements of the shaft configured and / or operable to co-operate with one or more magnetic elements of the drive member such that rotation of the shaft causes the driven member to move linearly and rotationally.1519. The magnetic transmission arrangement of any preceding claim, wherein at least one of the magnetic elements comprises or takes the form of a permanent magnet, e.g. a neodymium magnet; a samarium-cobalt magnet; an alnico magnet.20 20. The magnetic transmission arrangement of any preceding claim, wherein atleast one of the magnetic elements comprises or takes the form of an electromagnet.

21. The magnetic transmission arrangement of any preceding claim, wherein the transmission arrangement comprises a member configured and / or operable to block 25 magnetic flux.

22. A power tool comprising the magnetic transmission arrangement of any one of claims 1 to 21.30 23. The power tool of claim 22, wherein the power tool comprises or takes the formof a marine growth removal tool.

24. The power tool of claim 22 or 23, further comprising the rotary drive arrangement.

25. The power tool of claim 22, 23 or 24, wherein the power tool comprises:a housing configured to receive the drive member of the transmission arrangement,wherein the housing of the driven member is removably coupled to the housing5 of the drive member.14 02 2526. The power tool of any one of claims 22 to 25, wherein the power tool comprises, is coupled to and / or operatively associated with an onboard power supply, e.g. a battery.1027. The power tool of any one of claims 22 to 26, wherein the power tool comprises the tool head, and wherein the tool head comprises or takes the form of:a scraper;a blade, e.g. a saw blade;15 a brush.

28. A tool system comprising one or more tools according to any one of claims 22 to 27.20 29. The tool system of claim 28, wherein the tool system comprises a remotelyoperated vehicle (ROV).

30. A method for marine growth removal using of the transmission arrangement of any one of claims 1 to 21, the tool of any one of claims 22 to 27 or the tool system of 25 claim 28 or 29.

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