The present invention relates to a reeling device. In particular to a reeling device for the controlled coiling and uncoiling of a cable, which has the facility to lift and lower a load connected to an end of the cable. The present invention therefore relates to a reeling/lifting device.

It is widely known in the art to wind and unwind cables from a reeling device, wherein one end of the cable is fixed relative to the remainder of the cable, for providing a stationary electrical connection location, and the other end of the cable can be unreeled for deploying a desired length of cable. Such devices may be used when it is desired to lower and raise a device from a ceiling or otherwise. These devices must however make provision to avoid the stationary portion of the cable from twisting, kinking and ultimately failing as the reel is rotated during winding and unwinding of the cable.

There are a number of known solutions in the reeling device art.

In a first solution, slip rings are used to provide an electrical connection between the stationary and rotatable portions of the cable. A problem with slip rings, however, is that they can be the source of undesirable electrical noise and intermittent electrical contact. This is a particular concern when such a reeling device is used in connection with audio and data cables.

In a second solution, an arrangement such as that disclosed in US 5,526,997 is used. This arrangement comprises main and secondary reels that include a common hub member that is formed with a hole extending therethrough from the main reel to the secondary reel. The cable is wound upon the two reels with a first end portion of the cable being coiled upon the main reel, an intermediate portion thereof extending through the hole formed in the common hub member and a second end portion of the cable being coiled about the secondary reel. The second end portion of the cable is substantially shorter than the first end portion and includes an end that is fixed to the housing. With this arrangement, as the first portion of the cable is fully unwound from the main reel, the second portion of the cable is simultaneously unwound from and then rewound onto the secondary reel. A variation on this scheme uses a twin rotating reel and a rotating guide sheave to feed the cable from one of the rotating reels to a fixed reel and a further variation uses a twisting cable chain. Whilst these arrangements avoid the need for slip rings, they introduce alternative problems. The cable is usually coiled on the main reel in successive radial layers. This renders accurate positioning difficult, with accuracy decreasing over time due to compression of the cable. Such arrangements also require a ‘standing’ length of cable to be retained in the device (in some cases equal to or greater than the stroke of the device). In some applications, overall cable length can be critical and it is therefore desirable that a maximum length of the cable is deployed in the stroke of the device (i.e. a minimum length of the cable is retained within the device when the cable is fully deployed).

A further known solution is disclosed in WO 2021/099800 A1 . This arrangement comprises a first ‘static’ reel fixed against rotation and axial movement and a second ‘moving’ reel arranged coaxially with the static wheel. The moving reel is rotatable about the axis, with such rotation causing axial movement of the moving reel. An intermediate guide is provided for guiding a cable between the static and moving reels during coiling and uncoiling of the cable. In order to maintain correct alignment of the intermediate guide with the moving reel as the cable is coiled and uncoiled, the intermediate guide is arranged to rotate about and move axially along the axis of the moving reel. The rotation and axial movement of the intermediate guide are maintained in proportion to the rotation and axial movement of the moving reel in order to ensure that the intermediate guide remains aligned with the point of the moving reel at which the cable is fed on/off at all times.

In the prior art arrangement, this synchronisation between the intermediate guide and the moving reel is achieved by means of gear sets, which allow the rotational movement of a shaft driven by a motor to both the intermediate guide and the moving reel in a proportional manner. However, this arrangement has a number of drawbacks.

Firstly, the gear ratio is defined by number of teeth of the component gears, which must necessarily be an integral number. Accordingly, the use of gear sets does not allow complete freedom of the rotational speed ratio between the intermediate guide and moving reel.

Secondly, the use of gear sets introduces a number of component parts, which adds to the complexity of the device. This increases the burden of maintenance and the risk of mechanical failure. Such components also occupy space, thus increasing the overall dimensions of the device, as well as adding to the weight of the device. It is desirable to minimise the size and weight of the device, particularly when the device is mounted in an elevated position, for example.

The present invention arose in an attempt to provide a reeling device that addresses the above problems with the prior art.

According to the present invention there is provided a reeling device for the controlled coiling and uncoiling of a payload cable, the reeling device comprising first and second reels about which the payload cable adapted to be coiled and uncoiled in use, wherein the first and second reels are coaxial, the first reel is fixed against rotation and axial movement, and the second reel is rotatable about the axis with such rotation causing axial movement of the second reel relative to the first reel, the reeling device further comprising: at least one drive cable coiled about the first and second reels, the or each drive cable having a first end fixed with respect to the first reel and a second end fixed with respect to the second reel for rotation with the second reel; and a transfer member rotatable about the axis of the first and second reels, wherein rotation of the transfer member causes axial movement of the transfer member, the transfer member comprising one or more intermediate guides, the or each intermediate guide being arranged to guide the drive cable or one of the drive cables between the first and second reels.

The first reel and the second reel of the reeling device have a common central axis. Each reel is preferably substantially cylindrical in shape.

With the arrangement of the present invention, rotation of the second reel can be effected by rotation of the transfer member via the drive cable or drive cables. The drive cable is fixed with respect to each of the first and second reels. Preferably, the second end of the or each drive cable is fixed directly to the second reel.

Since the second end of the or each drive cable is fixed with respect to the second reel for rotation therewith, rotation of the transfer member carrying the drive cable causes rotation of the second reel by means of the frictional contact between the drive cable and the second reel. Accordingly, rotation of the second reel can be maintained in proportion with rotation of the transfer member, without requiring the use of gear sets. Rotation of the second reel causes axial movement of the second reel and rotation of the transfer member causes axial movement of the transfer member. Rotation and axial movement of the transfer member and the second reel can therefore be kept in synchronisation. The abovementioned problems are thereby overcome.

The first reel is fixed against rotation. Rotation of the transfer member about the central axis therefore reels the payload cable onto the first reel, or unreels the payload cable from the first reel, depending on the direction of rotation.

The reeling device may comprise first and second drive cables and the transfer member may comprise a first intermediate guide for guiding the first drive cable between the first and second reels and a second intermediate guide for guiding the second drive cable between the first and second reels. The first drive cable may be coiled about the first and second reels in an opposite direction to the second drive cable. Rotation of the second reel can thereby be effected in both directions.

With the arrangement of the present invention, rotation of the second reel is effected by rotation of the transfer member. Rotation of the second reel is therefore proportional to rotation of the transfer member. It is also preferred that axial movement of the second reel is proportional to axial movement of the transfer member. This may be achieved in a number of ways.

In one arrangement, the transfer member may be driven to move axially by means of a roller provided on the transfer member and received within a helical groove of the static first reel. Rotation of the transfer member causes the roller to progress along the helical groove and thereby moves the transfer member axially. The second reel may be driven to move axially by means of a static roller received within a helical groove of the second reel. Rotation of the second reel causes the roller to progress along the helical groove of the second reel but since the roller is static (i.e. in a fixed position relative to the central axis of the second reel), the second reel is moved axially during rotation. With this arrangement, axial movement of the second reel can be maintained in proportion to axial movement of the transfer member. It will be appreciated that the ratio between axial movement of the second reel and axial movement of the transfer member will depend on the relative pitches of the helical grooves and the relative circumferences of the first and second reels. Alternative means to maintain proportional axial movement between the second reel and the transfer member will be known to the skilled person.

The or each drive cable may be a wire rope, preferably a steel wire rope. This provides the required strength and permits the diameter of the drive cable to be relatively small.

Preferably, the first reel and/or the second reel comprises a first helical groove arranged to accommodate a payload cable, in use, and a second helical groove arranged to accommodate the or each drive cable. This helps ensure that the payload cable and drive cables are reeled onto the first and second reels accurately throughout the life of the device and prevents unintended overlap or tangling between the drive cables and the payload cable. The first helical grooves of the first and second drums are preferably arranged to receive a payload cable in a single layer without overlap. The second helical grooves of the first and second drums are preferably arranged to receive the or each drive cable in a single layer without overlap with the same or another cable.

The first and/or second helical grooves are preferably substantially semi-circular in cross-section at a base portion thereof. The base portion is the portion of the helical groove that lies closest to the central axis of the reel in a radial direction. Accordingly, the first and/or second helical grooves are preferably arranged to receive a payload cable or drive cable that is substantially circular in cross-section.

A pitch of the first helical groove is preferably equal to a pitch of the second helical groove. The first and second helical grooves of the first reel and/or the second reel may be arranged such that, in use, the payload cable and the or each drive cable have the same pitch circle diameter when coiled about said reel and accommodated within the respective first or second helical groove of said reel. In this context, the pitch circle diameter is to be understood as the diameter of one complete turn of a respective cable when coiled about said reel, when viewed in an axial direction. Where two cables have the same pitch circle diameter, the centre-points of the two cables lie at the same radial distance from the central axis.

The second helical groove may lie next to the first helical groove in a side-by-side manner in the axial direction of the first and second reels. The first and second helical grooves of the first and/or second reels may therefore be in the form of a double helix. Accordingly, in use, the payload cable may lie adjacent at least one of the first and second drive cables when coiled about the first and/or second reels. In one particular embodiment, the first and second helical grooves of each of the first and second reels are arranged such that, in use, the payload cable is coiled about the first/second reel next to at least one of the first and second drive cables, wherein the payload cable and said first or second drive cable have the same helical pitch and the same pitch circle diameter.

In some embodiments, a diameter of the second helical groove is smaller than a diameter of the first helical groove. The second helical groove is thereby arranged to accommodate a drive cable that has a diameter smaller than that of a payload cable with which the reeling device is intended to be used. Each of the first and second helical grooves may have a base portion in the form of an arc. The arc of the first helical groove may have a radius that is greater than the radius of the arc of the second helical groove. In this regard, the base portion of the first helical groove is to be understood as the innermost portion of the first helical groove that lies closest to the centre of the respective reel when viewed in cross section (i.e. the portion that lies closest to the central axis of the reel in a radial direction).

The first groove of the first and/or second reels may have an arc of diameter less than or equal to 20 mm, more preferably less than or equal to 15 mm and most preferably less than or equal to 10 mm. This allows the first groove to accommodate a payload of appropriate dimensions.

The second groove of the first and/or second reels may have an arc of diameter less than or equal to 10 mm, more preferably less than or equal to 5 mm and most preferably less than or equal to 2 mm.

The second helical groove may be located at a base portion of the first helical groove. With such an arrangement, a drive cable received within the second helical groove may be located beneath a payload cable in use of the reeling device. This permits the dimensions of the first and second reels to be minimised i.e. the first and second reels can be shorter and more compact in an axial direction than an arrangement in which the first and second helical grooves lie next to each other. The drive cable being received “beneath” the payload cable is to be understood as the drive cable being located closer to the central axis of the respective reel than the payload cable when viewed in cross section.

In such arrangements, it is preferred that a depth of the second helical groove of the second reel is greater than a depth of the second helical groove of the first reel. This ensures that proportional rotation and axial movement of the second reel relative to the transfer member can be maintained by selecting an appropriate depth of the second helical groove of the second reel. The depth of the helical grooves is to be understood as the dimension of the helical grooves in a radial direction of the first/second reel. The second helical groove of the second reel may have an elongate extent in a radial direction and may have a base portion in the form of an arc.

The reeling device may further comprise an intermediate guide for guiding a payload cable between the first and second reels. The intermediate guide for guiding a payload cable between the first and second reels is preferably fixed for rotation and axial movement with the transfer member and is most preferably fixed to the transfer member.

The or each intermediate guide of the reeling device is preferably arranged, in use, to guide one of the drive cables or a payload cable substantially tangentially with respect to the first and/or second reels. Accordingly, the drive cables and/or payload cable can be fed on/off the first and second reels in the correct position without unwanted twisting or kinking.

Preferably, at least one of the first end and the second end of the or each drive cable is fixed with respect to at least one of the first reel and the second reel by means of at least one tensioning device. This enables the drive cables to be installed within the reeling device and subsequently brought into tension about the first and second reels. In a preferred embodiment, the first end of the or each drive cable is connected to a frame of the reeling device by means of a tensioning device, such that the first end of the or each drive cable is fixed with respect to the first reel.

The reeling device may further comprise a payload cable having a first end that is fixed and a second end that is movable relative to the first end, wherein the payload cable is unbroken between its first and second ends. The first end of the payload cable is preferably fixed to allow for a stationary connection to be made. The payload cable may support any suitable device (or other payload) at its second end. The payload cable may be an electrical cable or an optic fibre. In one exemplary arrangement a microphone is supported and the payload cable is an electrical cable. The reeling device is suitable for lifting objects (e.g. a microphone or camera).

Preferably, a diameter of the or each drive cable is smaller than a diameter of the payload cable. The diameter of the or each drive cable may be less than or equal to half the diameter of the payload cable.

The payload cable may have a diameter less than or equal to 20 mm, more preferably less than or equal to 15 mm and most preferably less than or equal to 10 mm.

The or each drive cable may have a diameter less than or equal to 10 mm, more preferably less than or equal to 5 mm and most preferably less than or equal to 2 mm. Such dimensions provide the necessary strength and frictional contact, whilst minimising the space occupied by, and the weight of, the drive cable or cables.

In one particularly preferred embodiment of the present invention, the reeling device comprises first and second drive cables, the transfer member comprising a first intermediate guide for guiding the first drive cable between the first and second reels and a second intermediate guide for guiding the second drive cable between the first and second reels, wherein the first drive cable is coiled about the first and second reels in an opposite direction to the second drive cable, wherein rotation and axial movement of the second reel are proportional to the rotation and axial movement of the transfer member. Each of the first and second reels may comprise a first helical groove arranged to accommodate a payload cable, in use, and a second helical groove arranged to accommodate the or each drive cable, wherein a pitch of the first helical groove is equal to a pitch of the second helical groove.

Non-limiting embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a front isometric view of a reeling device according to a first embodiment of the present invention;

Figure 2 is a rear perspective view of the reeling device of Figure 1 ;

Figure 3 is an enlarged view of the reeling device of Figure 1 , showing a connection of a first end of first and second drive cables;

Figure 4 is an enlarged view of the reeling device of Figure 1 , showing a connection of a second end of first and second drive cables;

Figures 5a and 5b are front views of the reeling device of Figure 1 with the payload cable fully coiled and fully uncoiled, respectively;

Figures 6a and 6b are section views of a reeling device according to a second embodiment of the present invention, with the payload cable fully coiled and fully uncoiled, respectively;

Figure 7 is an enlarged sectional view showing the circled region of Figure 6a;

Figure 8 is a sectional view of the reeling device of Figure 1 ; and

Figures 9a and 9b are enlarged views showing the circled regions of the first and second reels of Figure 8, respectively.

With reference to Figures 1 to 5b, there is shown a reeling device 1 according to a first embodiment of the present invention. The reeling device 1 is configured for the controlled coiling and uncoiling of a payload cable 2 having a first end 2a that is fixed and a second end 2b that is movable relative to the first end 2a. The first end 2a is fixed to allow for a stationary connection to be made. The payload cable 2 may support any suitable device at its second end. The payload cable may be an electrical cable or an optic fibre, for example. In one exemplary arrangement a microphone (not shown) is supported and the payload cable 2 is an electrical cable. The payload cable 2 is unbroken between its first and second ends 2a, 2b.

The reeling device 1 comprises first and second reels 4, 6 about which the payload cable 2 is coiled. Figure 5a shows the payload cable 2 fully wound/coiled and Figure 5b shows the payload cable 2 fully unwound/uncoiled. The first and second reels 4, 6 are coaxial. The first reel 4 is fixed against rotation and axial movement. The second reel 6 is rotatable about a common central axis of the first and second reels 4, 6. Rotation of the second reel 6 causes axial movement of the second reel 6 relative to the first reel 4, as described below. The reeling device 1 comprises a first drive cable 8 and a second drive cable 10. Each of the first and second drive cables 8, 10 is coiled about the first and second reels 4, 6. The first drive cable 8 is coiled about the respective circumferences of the first and second reels 4, 6 in a first direction. The second drive cable 10 is coiled about the respective circumferences of the first and second reels 4, 6 in a second direction opposing the first direction.

Each of the first drive cable 8 and the second drive cable 10 has a first end 8a, 10a fixedly connected to the first reel 4 and a second end 8b, 10b fixedly connected to the second reel 6.

With reference to Figure 3, in the present arrangement the first end 8a of the first drive cable 8 is fixed with respect to the first reel 4 by means of a tensioning connector 12. The tensioning connector 12 connects the first end 8a of the first drive cable 8 to a portion 14a of a frame 14 of the reeling device 1 . The first reel 4 is fixed to the same portion 14a of the frame 14. Accordingly, the first end 8a of the first drive cable 8 is fixed with respect to the first reel 4 and is thus fixed against rotation and axial movement.

The first end 10a of the second drive cable 10 is fixed with respect to the first reel 4 by means of a further tensioning connector 12 in the same manner. The provision of tensioning connectors 12 allows the first and second drive cables 8, 10 to be brought into tension about the first and second reels 4, 6.

Referring now to Figure 4, the second end 8b of the first drive cable 8 is received within a recess 16 provided on the second reel 6 and is fitted with a crimp 18 to hold the second end 8b within the recess 16 when the first drive cable 8 is in tension. The second end 8b of the first drive cable 8 is thereby fixed with respect to the second reel 6 for rotation therewith. It will be appreciated that in alternative embodiments, the second end 8b of the first drive cable 8 may not be fixed directly to the second reel 6, provided it is fixed in a manner which permits rotation and axial movement with the second reel 6. However, it is preferred that the second end 8b of the first drive cable is fixedly connected directly to the second reel 6. Although not shown, it will be appreciated that the second drive cable 10 can be fixedly connected to the second reel 6 at a suitable location in an identical manner to the first drive cable 8.

Referring again to Figures 1 and 2, the reeling device 1 comprises a first intermediate guide 20 for guiding the first drive cable 8 between the first and second reels 4, 6 and a second intermediate guide 22 for guiding the second drive cable 10 between the first and second reels 4, 6. The first and second intermediate guides 20, 22 are provided on a transfer member 24. The transfer member 24 is rotatable about the central axis. By such an arrangement, as seen in Figures 1 and 2, the intermediate guides 20, 22 can guide the first and second drive cables 8, 10 substantially tangentially with respect to the second reel 4 at all times during reeling and unreeling of the cable 2.

The transfer member 24 comprises a tubular frame 26 centred on the axis of the first and second reels 4, 6. The first and second intermediate guides 20, 22 each comprise an arm 28, 30 connected to the tubular frame 26 so as to fix the first and second intermediate guides 20, 22 for rotation and axial movement with the tubular frame 26.

It will be appreciated that the tubular frame 26 may have various cross-sectional profiles. The tubular frame 26 may substantially circular in cross-section, however in other embodiments the tubular frame 26 may not be circular in cross-section.

Rotation of the transfer member 24 causes axial movement of the transfer member 24 and, concurrently, of the first and second intermediate guides 20, 22. By such axial movement, as seen in Figures 1 and 2, the first and second intermediate guides 20, 22 are suitably axially aligned with the point of the second reel 4 at which the cable is fed on/off the second reel 4 at all times. Rotation of the transfer member 24 also causes rotation and axial movement of the second reel 4 by means of the first and second drive cables 2, 4, as discussed in greater detail below.

In the present arrangement, the first and second intermediate guides 20, 22 each comprise first and second guide members 32a, 32b in the form of pulleys. With reference to the first intermediate guide 20 (shown most clearly in Figure 1), the first guide member 32a guides the first drive cable 8 with respect to the first reel 4 and the second guide member 32b guides the first drive cable 8 with respect to the second reel 6. For such purposes, the first guide member 32a overlaps with the first reel 4 when viewed in a radial direction and the second guide member 32b overlaps with the second reel 6 when viewed in a radial direction.

In accordance with the discussion above, the points of the first and second guide members 32a, 32b at which the first drive cable 8 is fed on/off the first and second guide members 32a, 32b are respectively axially aligned with the first and second reels 4, 6 at the points at which the cable 2 is fed on/off the first and second reels 4, 6.

The guide members 32a, 32b of the second intermediate guide 22 are arranged in an equivalent manner to the guide members 32a, 32b of the first intermediate guide 20.

The first and second guide members 32a, 32b comprise pulleys in the present arrangement, which is preferred to avoid wear on the cable. The guide members 32a, 32b could be otherwise arranged. They could, for example, be non-rotating and have a low- friction surface over which the respective drive cable 8, 10 can slide. By rotation of the transfer member 24, the guide members 32a, 32b (and the respective portions of drive cables extending between the guide members 32a, 32b) maintain tangential alignment with the first and second reels 4, 6 at all times.

With reference to Figure 2, a third intermediate guide 34 is provided for guiding the payload cable 2 between the first and second reels 4, 6. The third intermediate guide 34 comprises an arm 36 connected to the tubular frame 26 so as to fix the third intermediate guide 34 for rotation and axial movement with the tubular frame 26 and, concurrently, with the first and second intermediate guides 20, 22.

The third intermediate guide 34, further, as it rotates, acts to coil/uncoil the payload cable 2 from the first reel 4. In the present arrangement, as is preferred, the configuration of the intermediate guide 34 is such that the payload cable 2 is also guided substantially tangentially with respect to the first reel 4 at all times and such that the intermediate guide 34 is also suitably axially aligned with the point of the first reel 4 at which the payload cable 2 is fed on/off the first reel 4 at all times.

In the present arrangement, the third intermediate guide 34 comprises a set of pulley sheaves 38 arranged in an arc. The bend radius of the payload cable 2 passing over the third intermediate guide 34 is defined by the angle of the arc of the pulley sheaves 38. Accordingly, the bend radius can be suitably set according to the minimum allowable bend radius of the particular cable in use.

The payload cable 2 is fed on/off the first and second reels 4, 6 by terminal pulley sheaves 38a, 38b. The points of the terminal pulley sheaves 38a, 38b at which the payload cable 2 is fed on/off the third intermediate guide 34 are respectively axially aligned with the first and second reels 4, 6 at the points at which the payload cable 2 is fed on/off the first and second reels 4, 6.

Operation of the reeling device 1 will now be described.

In the present arrangement, rotation of the transfer member 24 is effected by rotation of a handle 40 coupled to the transfer member 24 by a shaft 42. The present arrangement is therefore operated manually, however alternative arrangements may be driven by an electric motor, such as a servomotor.

In order to deploy the payload cable 2, the transfer member 24 is driven to rotate in a clockwise direction as shown in Figures 1 and 2. That is, the transfer member 24 is driven to rotate in a clockwise direction as viewed in the direction indicated by arrow A in Figures 1 and 2. This rotational motion is transferred to the first intermediate guide 20 via the transfer member 24. As the first intermediate guide 20 rotates in a clockwise direction, the first drive cable 8 is guided onto the first reel 4, which remains fixed against rotation. The frictional connection between the first drive cable 8 and the second reel 6 causes the second reel 6 to rotate in the clockwise direction as the first drive cable 8 is unreeled from the second reel 6 and reeled onto the first reel 4.

As the second reel 6 rotates, the payload cable 2 is unreeled from the second reel 6. Figure 5a shows the reeling device 1 with the payload cable 2 fully wound/coiled and Figure 5b shows the reeling device 1 with the payload cable fully unwound/uncoiled. The third intermediate guide 34 rotates with the transfer member 24 to guide the payload cable 2 off the first reel 4 as the payload cable 2 is deployed.

Rotation of the second reel 6 causes axial movement of the second reel 6. With the axial movement of the second reel 6, it is possible to provide a zero fleet reeling device, i.e. a device where the radial and axial location and the orientation of the portion of the payload cable 2 adjacent the second end 2b of the payload cable 2 that is fed on/off the second reel 6 does not change during reeling unreeling of the payload cable 2, as shown most clearly in Figures 5a and 5b. This ensures accurate operation and ease of installation, for example where the payload cable 2 is required to drop though a small hole in a ceiling. An end guide 44 is preferably provided for guiding the payload cable 2 on/off the second reel 6. The end guide 44 is fixed against axial movement. In the present arrangement, the end guide 44 comprises a guide wheel.

Rotational movement of the shaft 42 is also transferred to the second intermediate guide 22 by the transfer member 24. As the second reel 6 rotates in a clockwise direction as shown in Figures 1 and 2 (i.e. as the payload cable 2 is deployed), the second drive cable 10 is unreeled from the first reel 4 and is guided onto the second reel 6 by the second intermediate guide 22.

In the reverse operation, the shaft 42 and transfer member 24 are rotated in the opposing direction (i.e. an anticlockwise direction when viewed in the direction indicated by arrow A in Figures 1 and 2). As the second intermediate guide 22 rotates in an anticlockwise direction, the second drive cable 10 is guided onto the first reel 4, which remains fixed against rotation. The frictional connection between the second drive cable 10 and the second reel 6 causes the second reel 6 to rotate in the anti-clockwise direction as the second drive cable 10 is unreeled from the second reel 6 and reeled onto the first reel 4. At the same time, the payload cable 2 is reeled onto the first and second reels 4, 6 and the first drive cable 8 is unreeled from the first reel 4 and is guided onto the second reel 6 by the first intermediate guide 20.

With the present arrangement, by coiling the first and second drive cables 8, 10 about the first and second reels 4, 6 in opposite directions, rotation of the second reel 4 can be effected in both directions. This permits both reeling and unreeling of the payload cable 2.

As shown in the figures, the payload cable 2 and the first and second drive cables 8, 10 are helically coiled about each of the first and second reels 4, 6 in a single layer without overlap. This helps ensure accuracy throughout the life of the device. In the present arrangement, the first and second reels 4, 6 are provided with a first helical groove 46 for guiding/aligning the payload cable 2 as it is coiled, wherein the payload cable 2 is accommodated within the first helical groove 46. The first and second reels 4,6 are also provided with a second helical groove 48 for guiding/aligning the first and second drive cables 8, 10 as they are coiled, wherein the first and second drive cables 8, 10 are accommodated within the second helical groove 48. The helical grooves 46, 48 are shown most clearly in Figures 6a to 9b and preferred arrangements of the first and second helical grooves 46, 48 are described in greater detail below.

In the present arrangement, both the first and second reels 4, 6 are provided with helical grooves. In alternative arrangements, the helical grooves may be provided on only one of the first or second reels 4, 6 or may be omitted entirely.

The mechanism by which axial movement of the second reel 6 will now be described with particular reference to Figures 6a and 6b. It must be appreciated, however, that numerous modifications may be made without impacting the operation of the reeling device 1 , as fundamentally defined by Claim 1 . The present invention is not to be limited to the exemplary mechanism described.

Figure 6a shows the reeling device 1 with the payload cable 2 fully coiled and Figure 6b shows the reeling device 1 with the payload cable 2 fully uncoiled. In this arrangement, the reeling device 1 comprises an electric motor 50 to drive the shaft 42, which is fixed against axial movement. A torque arm linkage 52 is connected to the shaft 42 by means of a bush 54, such that the torque arm linkage 52 is fixed for rotation with the shaft 42. The torque arm linkage 52 is in turn fixedly connected to the tubular frame 26 of the transfer member 24. The torque arm linkage 52 permits the tubular frame 26 to rotate with the shaft 42 but to move axially with respect to the shaft 42. The tubular frame 26 is centred on the shaft 42 by a bearing 58, which permits axial movement of the tubular frame 26 relative to the shaft 42. The shaft 42 will typically be low-friction coated to allow relative movement of the tubular frame 26 on the shaft.

A roller 56 is provided at an end of the tubular frame 26 and is received within the first helical groove 46 of the first reel 4. As the transfer member 24 rotates (driven by the shaft 42), the roller 56 progresses along the first helical groove 46 and thereby moves the transfer member 24 axially from the position shown in Figure 6a, in which the tubular frame 26 surrounds a major portion of the first reel 4, to the position shown in Figure 6b, in which the tubular frame 26 surrounds only a relatively small end portion of the first reel 4.

Axial movement of the second reel 6 is effected by means of a further roller 60 received within the first helical groove 46 of the second reel 6. The roller 60 is fixed against axial movement. As the second reel 6 rotates (driven by the first or second drive cables 8, 10), roller 60 progresses along the first helical groove 46 of the second reel 6 thereby moving the second reel 6 from the position shown in Figure 6a, in which the second reel 6 partially surrounds the tubular frame 26, and the position shown in Figure 6b, in which the second reel 6 does not surround the tubular frame 26. As can be seen from Figures 6a and 6b, such axial movement of the second reel 6 permits the axial and radial location from which the payload cable 2 is reeled on/off the second reel 6, and the orientation of the payload cable 2 as it is reeling on/off the second reel 6, to be kept constant at all times during reeling and unreeling of the payload cable 2.

By the above arrangement, rotation of the shaft 42 driven by motor 50 effects rotation and axial movement of the transfer member 24 and the second reel 6, without the need for a gear set to transfer rotational or axial movement between the components.

One or more brakes are preferably provided, particularly where the shaft 42 is driven by an electric motor. It is particularly preferable, as in the present arrangement, that a holding brake 62 is provided, which is preferably an electromagnetic brake. The holding brake 62 is directly connected to the first reel 4. The electromagnetic holding brake 62 may take any conventional form. There may be additional brakes provided and/or positivebreak direct struck limit switches.

As discussed above, each of the first and second reels 4, 6 comprises a first helical groove 46 for accommodating the payload cable 2 and a second helical groove 48 for accommodating the first and second drive cables 8, 10. Figure 7 provides an enlarged view of the circled portion of the second reel 6 shown in Figure 6a. As can be seen in Figure 7, the first helical groove 46 has a larger diameter than the second helical groove 48, in order to accommodate the larger diameter of the payload cable 2 with respect to the first and second drive cables 8, 10. In this regard, it will be appreciated that the first and second drive cables 8, 10 need only have a relatively small diameter in order to provide the required frictional contact with the second reel 6. The required strength and frictional contact of the first and second drive cables 8, 10 can be achieved with a steel wire rope, for example.

In the arrangement shown in Figure 7, the first and second helical grooves 46, 48 run next to each other in the form of a double helix. The first and second helical grooves 46, 48 have the same helical pitch. The first and second helical grooves 46, 48 are arranged such that the payload cable 2 and the first or second drive cables 8, 10 have the same pitch circle diameter when coiled about the second reel 6. This is illustrated in Figure 7, which shows that the centre points of both the payload cable 2 and the second drive cable 10 lie on the same radius R from the rotational axis of the second reel 6 and have the same pitch P. Accordingly, when viewed in an axial direction, the diameter of one complete turn of the payload cable 2 has the same diameter as one complete turn of the second drive cable 10. This arrangement ensures that rotation and axial movement of the second reel 6 (effected by the first and second drive cables 8, 10) are maintained in proportion to the rotation and axial movement of the transfer member 24. Synchronisation between the transfer member 24 and the second reel 6 can thereby be maintained.

Figure 8 shows the first embodiment of Figure 1 to 5b in cross section.

This arrangement differs from the second embodiment in that the second helical grooves 48 of the first and second reels 4, 6 are located within the first helical grooves 46. This is shown most clearly in Figures 9a and 9b, which show enlarged portions of the first and second reels 4, 6, respectively. The second helical grooves 48 are provided at a base portion of the first helical grooves 46. Accordingly, the first and second drive cables 8, 10 can be accommodated beneath the payload cable 2 in use of the reeling device 1 . In this regard, “beneath” is to be understood as closer to the central axis of the first and second reels in a radial direction.

This arrangement is particularly advantageous as it permits the length of the first and second reels 4,6 in an axial direction to be minimised, since it is not necessary to accommodate the two helical grooves 46, 48 in a side-by-side manner.

However, since the pitch circle diameters of the payload cable 2 and first/second drive cables 8, 10 are no longer the same, it is necessary to adjust the relative pitch circle diameter of the second drive cable 10 relative to the pitch circle diameter of the first drive cable 8 in order to maintain proportional rotation and axial movement of the second reel relative to the transfer member 24. This is achieved by increasing the depth D2 of the second helical groove 48 of the second reel 6 relative to the depth D1 of the second helical groove 48 of the first reel 4.

To achieve this increased depth D2, the second helical groove 48 of the second reel 6 has an elongate extent in a radial direction of the second reel. A base portion of the second helical groove 48 of the second reel 6 is in the form of an arc to receive the first/second drive cables 8, 10 having a substantially circular cross-section.

The differential X1 , X2 between the pitch circle diameter of the payload cable 2 and the pitch circle diameter of the first/second drive cables 8, 10 can be selected for each of the first and second reels 4, 6 in order to ensure that the second reel 6 rotates at a speed in the correct proportion to the rotation of the transfer member 24.

The necessary depth D2 of the second helical groove 48 of the second reel 4 will depend on the depth D1 of the second helical groove 48 of the first reel 4, the diameters of the payload cable and drive cable, the diameters of the first and second reels 4, 6 and the desired ratio of the rotation and axial movement of the second reel 6 with respect to the transfer member 24.

The invention has been described above with reference to specific embodiments, given by way of example only. It will be appreciated that different arrangements of the system are possible, which fall within the scope of the appended claims.