CABLE SPOOLING APPARATUS

Abstract

A cable spooling apparatus for use with a storage drum for spooling and storing cable. The cable spooling apparatus comprises a tensioning unit for adjusting the tension of a cable as it is being spooled onto the storage drum. The tensioning unit traverses a path between the opposite ends of the storage drum. Methods of spooling and unspooling cable using the apparatus are also disclosed.

Claims

1. A cable handling apparatus for use in conjunction with a storage drum for spooling cable, said apparatus comprising: a support; a travelling member moveably mounted to the support; a tensioning unit for adjusting the tension of said cable, the tensioning unit mounted on said travelling member and having a cable entry point and a cable exit point, whereby cable, when present, extends from the cable exit point to the storage drum; wherein the travelling member is moveably mounted to said support, such that the cable exit point traverses a path between first and second positions where the tensioning unit feeds cable to or from opposite first and second ends respectively of a cable storage portion of the storage drum.

2. A cable handling apparatus according to claim 1, wherein the travelling member and tensioning unit are configured such that the cable, when present, extends from the cable exit point to the storage drum in a straight line.

3. A cable handling apparatus according to claim 1, wherein the tensioning unit is a transfer unit, or a linear tensioning unit or a curved tensioning unit.

4. A cable handling apparatus according to claim 1 wherein the tensioning unit comprises a sheave and belt.

5. A cable handling apparatus according to claim 1, wherein the tensioning unit comprises two opposing belts which constrain the cable, when in place, to follow a curved path between the belts.

6. A cable handling apparatus according to claim 1, wherein the first and second positions are aligned with the first and second ends of the cable storage portion.

7. A cable handling apparatus according to claim 1, wherein the tensioning unit and travelling member function as a spooling unit.

8. A cable handling apparatus according to claim 1, wherein the travelling member is pivotably mounted to the support (typically at the first end).

9. A cable handling apparatus according to claim 8, wherein the path between the first and second positions is curved.

10. A cable handling apparatus according to claim 1, wherein the travelling member is translatably coupled to the support such that the cable exit point moves laterally between the first and second positions in use.

11. A cable handling apparatus according to claim 1, further comprising a travelling member drive mechanism to drive the movement of the travelling member relative to the support.

12. A cable handling apparatus according to claim 11, in which the mechanism comprises a hoisting screw, a self-reversing screw, a belt, a linear actuator, or any other means of controlled motion.

13. A cable handling apparatus according to claim 1, comprising a drive mechanism configured to both drive the tensioning unit to feed cable and to drive rotation of a storage drum to wind cable in concert.

14. A cable handling apparatus according to claim 11, further comprising a motor to operate said mechanism to drive.

15. A cable handling apparatus according to claim 1, wherein said tensioning unit comprises separate first and second gripping regions, spaced along the length of the cable, wherein at each region the cable is gripped from both sides and urged in an axial direction in use.

16. A method of spooling a cable onto a storage drum, the method utilising a tensioning unit to tension said cable, whereby said cable enters a cable entry point of said tensioning unit and exits at a cable exit point of said tensioning unit, whereby the tensioning unit travels in use such that the cable exit point of the tensioning unit traverses a path between first and second positions wherein in the first position it feeds cable to a first end of a cable storage portion of the storage drum and in the second position it feeds cable to an opposite second end of the cable storage portion of the storage drum.

17. A method according to claim 16, wherein the cable exit point of the tensioning unit travels along a curved path between the first and second positions and back again and the tensioning unit rotates in use.

18. A method according to claim 16, wherein the cable exit point of the tensioning unit travels along a straight path between the first and second positions and back again and the tensioning unit translates laterally in use.

19. A method according to claim 16, wherein the method comprises driving the tensioning unit to feed cable and driving the rotation of the storage drum in concert such that the force used to urge the cable through the tensioning unit onto the storage drum is shared between the tensioning unit and the storage drum.

Description

DESCRIPTION OF THE DRAWINGS

[0037] Example embodiments of the present invention will now be illustrated with reference to the following Figures in which:

[0038] FIG. 1 is a schematic diagram of a known spooling arrangement;

[0039] FIG. 2 is a schematic diagram of a spooling arrangement according to the present invention;

[0040] FIG. 3 is a schematic diagram of a pivotably mounted tensioning unit for use with the invention;

[0041] FIGS. 4A and 4B are schematic diagrams of the tensioning unit of FIG. 3 with the cable exit point at the first position and the second position respectively; and

[0042] FIG. 5 is a schematic diagram of a drive gear arrangement for belts for the spooling arrangement of the present invention.

[0043] FIGS. 6A and 6B show schematic diagrams of the tensioning unit mounted in working configuration with a storage drum.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0044] With reference to FIG. 2, a cable spooling apparatus (1) according to the invention comprises a tensioning unit (also known as a transfer unit), in this case a linear tensioning unit (2) (LTU). The LTU is, or is attached to, a member which moves in use, referred to as a travelling arm (16). The travelling arm (16) is pivotably mounted to a base (18). In use, cable (4) extends into the LTU where it engages with a cable entry point (20) of the LTU and passes through the LTU to a cable exit point (22). In FIG. 2 the cable exit point (22) is shown in a first position (24), at one extent of its travel. The fleet angle is shown as a. In the first position (24), the LTU is aligned such that cable from the LTU passes in a straight line to the first end (12) of a cable storage portion (6) of the storage drum (8). The travelling arm (16) may pivot around the base (18) until, at the other extent of its travel, the cable exit point (22) is at a second position (26) from which cable from the LTU passes in a straight line to the opposite second end (14) of cable storage portion (6) of the storage drum (8).

[0045] The storage drum (8) is coupled to a storage drum motor (28) which drives rotation of the storage drum (8) around its axis during operation. A travelling arm motor (27) is coupled to the travelling arm to drive rotational motion of the travelling arm (16) around the pivot. A controller (29), such as a microprocessor or microcontroller, is in electronic communication with the storage drum motor (28), travelling arm motor (27) and the tensioning unit motor (40), for example through wires, and is configured to drive the motors in concert as will be described. One skilled in the art will appreciate that the motors illustrated in FIG. 2 may also be implemented using only two, or only one motor, with a suitable mechanical transmission.

[0046] During operation, in order to spool cable (4) onto the storage drum (8), the LTU (2) and storage drum motor (28) are driven together to urge cable (4) through the LTU onto the storage drum (8), which rotates in order to take up the cable (4). The LTU (2) and the storage drum motor (28) share the load of pulling the cable (4). Each provides a force to urge the cable onto the storage drum (8). This distribution of force reduces the maximum axial force which must be applied to the cable at any one point. The speed of movement of cable through the LTU (2) and the tangential speed of rotation of the storage drum (8), given the thickness of cable already stored on the storage drum (8) are generally the same.

[0047] During spooling onto the storage drum, while the LTU (2) and storage drum motor (28) are operated, the travelling arm (16) is moved by the travelling arm motor (27) so that the cable exit point (22) of the LTU (2) moves smoothly along an arc from the first position (24) to the second position (26) and back again. Thus, the travelling arm (16) functions as a spooling device, feeding cable and directing cable back and forth along the cable storage portion (6) of the storage drum (8). The first and second positions (24, 26) of the cable exit point (22) are aligned with the first and second ends (12, 14) of the cable storage portion (6). The first and second positions are spaced apart by the same distance as the end of the cable storage portion except for a small margin due to the fleet angle, again up to about 2° at either end which means that the first and second ends (12, 14) of the cable storage portion (6) may be slightly further apart than the first and second positions (24, 26) of the cable exit point (22).

[0048] FIG. 3 illustrates machinery for driving the travelling arm (16) and tensioning unit (2) (in this case a curved tensioning unit) in a practical implementation. In this example, the tensioning unit comprises two rubber belts (30) and a spring loading pad (32), and a fixed loading pad (34), which is out of sight in FIG. 3. The belts (30) extend around pulleys (36) and have a central groove (38) within which the cable (4) is located and compressed (squeezed between the loading pads (32, 34)) during operation. A belt drive motor (40) provides force to moves the belts (30) to urge a cable (4) through the tensioning unit (2) in use. The travelling arm (16) and tensioning unit (2) are mounted on pivot bearings (42). A travelling arm motor (27) drives movement of the travelling arm (16) and tensioning unit (2) through a drive screw (44). Fairleads (46, 48) at the cable entry point (20) and cable exit point (22) guide cable through the device. FIGS. 4A and 4B show the travelling arm (16) and tensioning unit (2) at the opposite first and second ends of its range of movement. FIG. 5 provides more detail of the drive gear arrangement for the belts. The belt drive motor (40) drives a rotating shaft and gear (46) which drives belt gears (50) via intermediate gear (48). Rotation of the belt gears (50) moves the belts (30) unaffected by pivoting of the travelling arm (16) and tensioning unit (2) around pivot bearings (42). It may also be that only one belt is driven.

[0049] By forming the tensioning unit (2) as part of a travelling arm (16) which pivots in use, the space required for the apparatus is substantially reduced. In the arrangement of FIG. 1, the requirement for the fleet angle to not exceed around 2° means that the overall length of the apparatus is substantial. In the arrangement of FIG. 2, the tensioning unit (2) moves through what was effectively space for the cable to flex in the arrangement of FIG. 1 and so the overall device is more compact. In this arrangement, the travelling arm (16) and tensioning unit (2) effectively function as a spooling device.

[0050] In practice, the cable (4) curves slightly at the fairlead (46) at the cable entry point (20), within the limiting radius of curvature of the cable. The cable extends in a straight line from the cable exit point (22) to the cable storage portion (6) of the storage drum (8).

[0051] In order to unspool the cable (4), the tensioning unit (2) and storage drum motor (28) are operated in reverse. Cable thus passes from the cable storage portion (6) of the storage drum (8) through the tensioning unit (2), but in this case from cable exit point (22) to cable entry point (22). Again, the travelling arm (16) pivots so that the cable exit point (22) moves in an arc between the first and second positions (24, 26) and the force to urge the cable is distributed between the tensioning unit (2) and storage drum motor (28).

[0052] In the example of FIG. 2, the tensioning unit is a linear tensioning unit (2). However, the person skilled in art will be aware of alternative tensioning units which are also useful for the purposes of the invention. For example, a tensioning unit may be formed by two curved belts, or by a single curved belt and a sheave between which the cable (4) is held and urged in use, and moved in the same way as part of a travelling arm. In these cases, the cable curves within the tensioning unit but would leave the cable exit point (22) to the storage drum in a straight line.

[0053] Although in the example shown in FIG. 2, the travelling arm (16) pivots relative to the base, It would also be possible for the travelling arm (16) to move laterally, backwards and forwards, relative to the base, between first and second positions (22, 26 respectively) for the cable exit point (22) at which cable is fed to first and second ends (12, 14 respectively) of the cable storage portion (6) of the storage drum (8).

[0054] Schematic diagrams of the cable handling apparatus in its working configuration together with a storage drum for spooling cable are shown in FIGS. 6A and 6B.

[0055] Further modifications and variations may be made within the scope of the invention herein disclosed.