Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
1999-10-21
2002-10-29
Wu, Daniel J. (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S531000, C340S539230, C073S763000
Reexamination Certificate
active
06472983
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an anchor and anchor chain monitoring device for anchored floating objects, in particular ships.
BACKGROUND
During a ship's voyage, monitoring devices are called into service to determine force acting on a securing mooring apparatus either in a harbor or on a floating buoy apparatus and, whenever necessary, should this force exceed a predetermined value, to trigger an appropriate measure in order to prevent the securing apparatus from renting and the respective floating vessel from then being carried unchecked into the waterway.
A method and a device for monitoring the force acting on a mooring hawser of a single-point mooring device during loading and unloading of a ship is known from DE-AS 21 34 104. According to this known method, the bow of the ship is fastened to the single-point mooring device via the mooring hawser in such a manner that the ship can swing freely and unhindered about the mooring hawser. In this state, the force acting on the mooring hawser is measured and transformed into a signal which is a gauge of the measured force acting on said hawser and which then is transmitted from the single point mooring device onto land or to the ship. The mooring hawser between the ship and the single point mooring device is then released as soon as the transmitted signal displays that force acting on the hawser exceeds a predetermined upper threshold value.
DE-GM-73 16 102 discloses an anchoring apparatus for a floating vessel utilizing a point-anchoring system with a plurality of hawsers. A monitoring means is provided having a monitoring station for receiving and displaying the signals from a plurality of stress meters in order to measure the mechanical stress in the hawser. An interim piece between the hawser securing section and a securing base member is disposed with a stress meter for this purpose.
A dynamic anchoring of ships and similar floating objects is known from DE-OS-2 410 528 in which a propelling means is provided and the ship on the surface of the water is anchored perpendicular to a first fixed point on the sea bed. A buoy, provided with its own dynamic anchoring means, is anchored at a distance from the ship such that no machine or apparatus located either on the ship or on said first sea bed fixed point can interfere with said dynamic anchoring means and the buoy in this manner is able to attain a fixed position with reference to a second point on the sea bed. With help of a measuring device located on the surface, working in concert with a ship's course determining device, the relative position of the ship with respect to buoy and course is determined. Any deviation in position of the ship with respect to the first given sea bed point is corrected by an anchoring means operation respective to delivered error signals of the measuring device.
DE-OS-2 410 528 further describes a buoy encompassing dynamic anchoring means as well as electromagnetic signal transmitter and reflector means.
A method for positioning a watercraft is known from DE-OS-25 02 020 with which a ship is always kept within an outer circle corresponding to the largest permissible inclination of a drilling mud return pipe, a riser, respectively. To this purpose, an anchoring arrangement is employed, as is a plurality of computer-controlled propellers with blades pivotal about a vertical axis. The computer only actuates the propellers after the resultant of the external force acting on the ship or the riser tube angle of inclination exceeds a certain predetermined value.
When values of external force or riser tube angle of inclination remain under the predetermined threshold value, only the compensating by the anchoring arrangement itself serves to keep the ship within a smaller inner circle which has a smaller radius than the radius of the outer circle.
A shear pin for retaining means is known from DE-GM-77 15 093, in particular for mooring arrangements, having sectionally decremental reductions at a measuring point. Stress sensors are arranged in an axle bore of the shear pin; their cavity filled with an sealing compound which hardens subsequent to introduction. The stress sensors are comprised of strain gages which are arranged in pairs at the measuring point and connected via conduits to an electrical circuit.
Cable works with a core are known from DE-OS-27 48 922, in particular for mooring of ships. The core consists of a cable connectable to an indicator system by at least two cable wires. Coexistent its mechanical connection, the cable works also has a clutch which serves for non-contact switching of the cable, whereby one coupling half is arranged at the cable works end and the other half is arranged at a distance thereto. In both coupling halves, moreover, an engageable locking and securing agent is provided. The coupling half disposed at the cable works end has a read contact under its front end at which the cable end is connected; under the front end of the other coupling half, a permanent magnet is disposed which works in concert with the read contact.
A monitoring or alarm system for ship anchor chains is known from GB 2 265 468 A in which a stress sensor controlled by a control means continually measures the tension in an anchor chain. The momentary measured anchor chain tension is compared with a predetermined tension or with the maximum measured tension recorded during the current anchored period, and the control means emits a warning signal when the anchor chain tension is higher than a predetermined critical value. Transmission of the signals between the sensor and the control means can ensue via a cable connection as well as through propagation of electromagnetic waves.
From U.S. Pat. No. 3,823,395, a means for monitoring the payload on cranes and similar contrivances is known. Said means can determine the weight load. A transmitter allocated to the sensor transmits the measured signal to a receiver which in turn shows the signal on a display.
U.S. Pat. No. 4,912,464 discloses an anchor warning device for ships in which a motion detector is arranged on the anchor of a ship and which emits an alarm signal upon significant movement of a sunk anchor.
From U.S. Pat. No. 5,086,651, a device and a method for measuring the mechanical strain in a structural member is known. A material is employed which undergoes a change in phase when strained so that the mechanical strain of a system can be determined through a measurement of the phase change. To effect an even more precise determination, a plurality of elements may be arranged for the monitoring of a complex system, each of said elements formed respectively from one material.
EP-A-0 242 115 defines a method and a system for determining position on a moving platform, for example a ship, utilizing signals from GPS satellites. In this known method, the satellite signals received directly at the moving platform are compared with satellite signals received indirectly through interposing from a base station, thereby determining the momentary position of the moving platform.
The problematic nature of anchors for floating objects will first be described using the example of an anchored ship.
To anchor, a ship lowers an anchor hanging on an anchor chain or hawser onto the waterway bottom so that the anchor, as well as also a large portion of the anchor chain/hawser lies on the sea bottom. What is important here is that the fixation of the ship at a certain area is not effected through the anchor connecting with the sea floor, but rather through the weight imposed on the portion of the anchor chain/hawser lying on the sea floor.
An anchored ship thus can, within a certain given range, move freely about the leverage point of the anchor chain/hawser on the sea bottom biasing the ship, thereby allowing for some give against external forces acting on the ship, as for example the force of currents or winds. As the amount of such external forces acting on the ship increase, this may led to the reaching of a particular condition, dependent upon a value based on weight and the l
Deep Blue Technology AG
Murphy James J.
Nguyen Phung
Schwartz Richard
Winstead Sechrest & Minick
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