MOORING DEVICE AND A METHOD FOR OPERATING A MOORING DEVICE

Abstract

A mooring device (100) includes a method for operation. The mooring device (100) has an attachment unit (101) including a contact surface (102) for contacting a surface of an object (201) to be attached and at least one magnet for generating a magnetic field through the contact surface (102) to the object (201), a regulator (104) for adjusting the magnetic field generated by the at least one magnet, a telescopic arm (105) pivotally attached to the attachment unit (101), a first hydraulic cylinder (106) and a second hydraulic cylinder (107) attached to the telescopic arm (105), and a monitor for monitoring linear displacements of the first hydraulic cylinder (106) and the second hydraulic cylinder (107). The regulator (104) is configured, based on the linear displacements, to adjust the magnetic field so that an attachment point on the surface of the object (201) can be changed.

Claims

1. A mooring device, comprising: an attachment unit that comprises a contact surface for contacting a surface of an object to be attached and at least one magnet for generating a magnetic field through the contact surface to the object, and means for adjusting the magnetic field generated by the at least one magnet, a telescopic arm pivotally attached to the attachment unit, a first hydraulic cylinder and a second hydraulic cylinder attached to the telescopic arm, and means for monitoring linear displacements of the first hydraulic cylinder and the second hydraulic cylinder, wherein the adjusting means is configured, based on the linear displacements, to adjust the magnetic field so that an attachment point on the surface of the object is changeable.

2. The mooring device according to claim 1, wherein the adjusting means is configured, when the attachment unit is attached to the object and at least one of the linear displacements exceeds a first threshold value specific to each hydraulic cylinder, to decrease the magnetic field so that the attachment unit can slide on the surface of the object, and when the attachment unit slides on the surface of the object and the linear displacements fall below a second threshold value specific to each hydraulic cylinder, to increase the magnetic field so that the attachment unit becomes stationary relative to the object.

3. The mooring device according to claim 1, wherein the monitoring means comprises a first linear displacement sensor installed into the first hydraulic cylinder and a second linear displacement sensor installed into the second hydraulic cylinder.

4. The mooring device according to claim 1, wherein the telescopic arm comprises a third hydraulic cylinder, the mooring device comprises means for monitoring a force exerted on the third hydraulic cylinder, and the adjusting means is configured to adjust the magnetic field based on the force.

5. The mooring device according to claim 4, wherein the adjusting means is configured, when the attachment unit is attached to the object and the force exceeds a third threshold value, to decrease the magnetic field so that the attachment unit detaches from the object.

6. The mooring device according to claim 4, wherein the monitoring means comprises a pressure sensor for measuring a hydraulic pressure in the third hydraulic cylinder.

7. The mooring device according to claim 1, wherein the mooring device comprises a shock absorbing element for absorbing shocks exerted on the telescopic arm.

8. The mooring device according to claim 1, wherein the mooring device comprises means for sensing a contact between the contact surface and the surface of the object.

9. The mooring device according to claim 1, wherein the magnet is a bi-stable permanent magnet.

10. A vessel comprising a mooring device according to claim 1 for mooring the vessel to a mooring structure.

11. A mooring structure comprising a mooring device according to claim 1 for mooring a vessel to the mooring structure.

12. A method for operating a mooring device according to claim 1, wherein the method comprises: moving the contact surface of the attachment unit into contact with a surface of an object to be attached, attaching to the object by generating, with the at least one magnet, a magnetic field through the contact surface to the object, monitoring linear displacements of the first hydraulic cylinder and the second hydraulic cylinder, and adjusting, based on the linear displacements, the magnetic field so that an attachment point on the surface of the object is changed.

13. The method according to claim 12, wherein the step of adjusting the magnetic field comprises, if at least one of the linear displacements exceeds a first threshold value specific to each hydraulic cylinder, decreasing the magnetic field so that the attachment unit slides on the surface of the object, and if, when the attachment unit slides on the surface of the object, the linear displacements fall below a second threshold value specific to each hydraulic cylinder, increasing the magnetic field so that the attachment unit becomes stationary relative to the object.

14. The method according to claim 13, wherein the step of adjusting the magnetic field comprises using the first hydraulic cylinder and the second hydraulic cylinder to facilitate the sliding of the attachment unit on the surface of the object.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIGS. 1A-1B illustrate a mooring device according to an embodiment of the invention, and

[0039] FIGS. 2A-2C illustrate the use of the mooring device according to FIGS. 1A-1B.

DETAILED DESCRIPTION OF THE DRAWINGS

[0040] FIGS. 1A-1B illustrate a mooring device according to an embodiment of the invention, viewed from two different directions. The mooring device 100 can be mounted to a vessel or a mooring structure for mooring the vessel to the mooring structure.

[0041] The mooring device 100 comprises an attachment unit 101 that comprises a contact surface 102 for contacting a surface of a metal plate (not shown) that can be attached to the vessel or the mooring structure, and a plurality of magnets (not shown) for generating a magnetic field through the contact surface 102 to the metal plate. The magnets are arranged inside a housing 103 of the attachment unit 101. The mooring device 100 comprises a control unit 104 for adjusting the magnetic field generated by the magnets. The attachment to the metal plate is achieved by arranging the contact surface 102 in contact with a surface of the metal plate, and then by generating with the magnets a magnetic field through the contact surface 102 to the metal plate.

[0042] The mooring device 100 comprises a telescopic arm 105 and two hydraulic cylinders 106 and 107 for moving the attachment unit 101. A first end of the telescopic arm 105 is pivotally attached to the attachment unit 101, and a second end of the telescopic arm 105 can be pivotally attached to the vessel or the mooring structure. The telescopic arm 105 comprises an outer arm 108 and an inner arm 109 that is arranged to be moveable relative to the outer arm 108 in the longitudinal direction of the telescopic arm 105 so that the length of the telescopic arm 105 can be adjusted. The inner arm 109 can be moved relative to the outer arm 108 by using a hydraulic cylinder (not shown). First ends of the hydraulic cylinders 106 and 107 are pivotally attached to the outer arm 108, and second ends of the hydraulic cylinders 106 and 107 can be pivotally attached to the vessel or the mooring structure.

[0043] The hydraulic cylinders 106 and 107 comprise linear displacement sensors (not shown) for measuring linear displacements of the hydraulic cylinders 106 and 107. The linear displacement sensors measure the amount of rod extension relative to a reference position. When the attachment unit 101 is attached to the metal plate, the linear displacements of the hydraulic cylinders 106 and 107 provide information on the relative movement between the vessel and the mooring structure.

[0044] The control unit 104 is configured, based on the linear displacements of the hydraulic cylinders 106 and 107, to adjust the magnetic field generated by the magnets so that an attachment point on the surface of the metal plate can be changed. The attachment point on the surface of the metal plate is changed by decreasing the magnetic field in such a manner that the attachment unit 101 can slide on the surface of the metal plate, and when the attachment unit 101 has slid to a desired position, increasing the magnetic field so that the attachment unit 101 becomes stationary relative to the metal plate. The hydraulic cylinders 106 and 107 are used to facilitate the sliding of the attachment unit 101 from one attachment point to another on the surface of the metal plate.

[0045] The hydraulic cylinder of the telescopic arm 105 comprises a pressure sensor (not shown) for measuring a hydraulic pressure in the hydraulic cylinder. The hydraulic pressure is indicative of the force exerted on the telescopic arm 105 and it is utilised by the control unit 104 to detach the attachment unit 101 from the metal plate when the hydraulic pressure exceeds a predetermined threshold value so that the mooring device 100 can be protected from being damaged.

[0046] FIGS. 2A-2C illustrate the use of the mooring device according to FIGS. 1A-1B. In FIG. 2A, there is shown a situation where the attachment unit 101 is moved towards a metal plate 201 by using the telescopic arm 105. The attachment unit 101 is moved until the contact surface 102 comes into contact with the surface of the metal plate 201. After the contact, the magnets are adjusted to generate a magnetic field through the contact surface 102 to the metal plate 201, whereby the attachment unit 101 attaches to the metal plate 201. This situation is shown in FIG. 2B.

[0047] When the attachment unit 101 is attached to the metal plate 201, the telescopic arm 105 is fixed so that its length does not change and the hydraulic cylinders 106 and 107 are arranged in a floating mode, which allows the telescopic arm 105 to pivot about its second end. When the vessel moves relative to the mooring structure, the linear displacements of the hydraulic cylinders 106 and 107 change. By measuring the linear displacements of the hydraulic cylinders 106 and 107, the need for changing the attachment point on the surface of the metal plate 201 can be identified. The attachment point on the surface of the metal plate 201 is changed by adjusting the magnetic field based on the linear displacements of the hydraulic cylinders 106 and 107 in the following manner. When at least one of the linear displacements exceeds a first threshold value specific to each hydraulic cylinder 106 and 107, the magnetic field is decreased so that the attachment unit 101 can slide on the surface of the metal plate 201. The hydraulic cylinders 106 and 107 are used to facilitate the sliding of the attachment unit 101 on the surface of the metal plate 201. Once the linear displacements fall below a second threshold value specific to each hydraulic cylinder 106 and 107, the magnetic field is increased so that the attachment unit 101 becomes stationary relative to the metal plate 201. The situation where the attachment unit 101 has moved to another attachment point is shown in FIG. 2C.

[0048] Only advantageous exemplary embodiments of the invention are described in the figures. It is clear to a person skilled in the art that the invention is not restricted only to the examples presented above, but the invention may vary within the limits of the claims presented hereafter. Some possible embodiments of the invention are described in the dependent claims, and they are not to be considered to restrict the scope of protection of the invention as such.