Mooring cable tension monitoring system

Abstract

The mooring cable tension monitoring system includes a winch drum (3) for winding the mooring cable (11) and a belt brake (4) including a brake drum (41) that rotates together with the winch drum (3). In addition, the mooring cable tension monitoring system includes: a roll number detector for detecting the number of rolls of the mooring cable (11) on the winch drum (3); a weighing sensor (5) assembled to the belt brake (4) for measuring belt tension; and a control device for calculating the tension acting on the mooring cable (11) based on the number of rolls of the mooring cable (11) detected by the roll number detector and the belt tension measured by the weighing sensor (5).

Description

Technical Field

[0001] This invention relates to a cable tension monitoring system. Background Technology

[0002] Ships are equipped with winches for mooring lines to docks, etc. During mooring, due to changes in sea conditions and weather, excessive tension can sometimes occur on the mooring lines, causing them to break. Therefore, it is desirable to monitor the tension of the mooring lines during mooring.

[0003] For example, Patent Document 1 discloses a mooring cable tension monitoring system (referred to as a "mooring cable monitoring device" in Patent Document 1) that can monitor the tension of the mooring cable during mooring. In this system, a separate drum including a storage drum and a tension drum is used as the winch drum, and a load cell is assembled on a band brake including a brake drum. Then, during mooring, the mooring cable is wound on the tension drum of the winch drum. The radius from the center of the winch drum to the line of action of the tension is constant, and the load measured by the load cell is converted into the mooring cable tension.

[0004] Existing technical documents:

[0005] Patent documents:

[0006] Patent document 1: Japanese Patent Application Publication No. 2002-211478. Summary of the Invention

[0007] The problem the invention aims to solve:

[0008] However, because the separation drum is longer than the tension drum of a typical winch (the axial width of the drum is wider), the location for installing the winch is limited when using the separation drum. Moreover, in the mooring tension monitoring system of Patent Document 1, the mooring cable needs to be wound around the tension drum during mooring.

[0009] Therefore, the object of the present invention is to provide a mooring tension monitoring system that can monitor the tension of the mooring line during mooring without using a separation drum.

[0010] Solution methods:

[0011] To solve the above problems, the mooring cable tension monitoring system of the present invention is characterized by comprising: a winch drum for winding the mooring cable; a belt brake including a brake drum that rotates together with the winch drum; a roll number detector for detecting the number of rolls of the mooring cable on the winch drum; a weighing sensor assembled to the belt brake for measuring belt tension; and a control device for calculating the tension acting on the mooring cable based on the number of rolls of the mooring cable detected by the roll number detector and the belt tension measured by the weighing sensor.

[0012] Based on the above structure, the number of layers of the mooring cable on the winch drum is detected by a layer count detector. Therefore, instead of keeping the radius from the center of the winch drum to the line of action of tension constant, the tension of the mooring cable can be calculated using the number of layers. Thus, the tension of the mooring cable during mooring can be monitored without a separation drum.

[0013] Invention effects:

[0014] According to the present invention, a mooring tension monitoring system is provided that can monitor the tension of the mooring line during mooring without using a separation drum. Attached Figure Description

[0015] Figure 1 This is a front view of the mechanical part of a mooring cable tension monitoring system according to an embodiment of the present invention;

[0016] Figure 2 It is along Figure 1 A sectional view of line II-II;

[0017] Figure 3 This is a schematic structural diagram of a belt brake;

[0018] Figure 4 This is a diagram showing a modified example of the roll layer number detector;

[0019] Figure 5 This is a diagram showing another variation of the roll layer number detector;

[0020] Figure 6 This is a diagram showing another variation of the roll layer number detector;

[0021] Figure 7 This is a schematic structural diagram of a modified band brake. Detailed Implementation

[0022] Figure 1 and Figure 2 The diagram illustrates a mooring tension monitoring system 1 according to an embodiment of the present invention. The system 1 includes a winch drum 3 rotatably supported by a support platform 30 disposed on the deck 10 of a ship and a band brake 4 that allows or prevents the rotation of the winch drum 3 (so-called braking).

[0023] The winch drum 3 has a mooring cable 11 wound around it. Figure 1 (The details are omitted for simplicity in the drawing). The flange 31 protrudes radially outward from both ends of the winch drum 3.

[0024] The winch drum 3 is driven by the prime mover 22 via the reducer 23. A band brake 4 is disposed along the flange 31 on the side of the reducer 23, and a clutch 24 is provided between the band brake 4 and the reducer 23. In this embodiment, the clutch 24 is manual.

[0025] The prime mover 22 can be an electric motor or a hydraulic motor. In this embodiment, the prime mover 22 is equipped with an operating device 21, and the prime mover 22 is operated manually. However, the prime mover 22 can also be electrically controlled by the control device 8 described later.

[0026] In this embodiment, the band brake 4 is manually operated. Specifically, the band brake 4 is as follows: Figure 3 As shown, it includes a brake drum 41 fixed to the flange 31. That is, the brake drum 41 rotates together with the winch drum 3. Furthermore, the band brake 4 includes a pair of arc-shaped belts 42 and 43. One end of the belts 42 and 43 is connected to each other by a pin 44, and the other ends of the belts 42 and 43 are respectively provided with pins 45 and 46.

[0027] Pins 45 and 46 are connected to linkage 47, which moves pins 45 and 46 closer together or further apart depending on the rotation of the operating shaft 48. Linkage 47 is also connected to the support column 12 mounted on the deck 10 via pin 49. In this embodiment, the pin 45 located directly above the support column 12 is a pin-type load cell 5. In other words, the load cell 5 is mounted on the band brake 4.

[0028] When pins 45 and 46 approach each other via linkage 47 and belts 42 and 43 tighten the brake drum 41, the belt tension F acts upward on the load cell 5. That is, the load cell 5 measures the belt tension F. Additionally, when tension P acts on the mooring cable 11, this tension P generates a rotational force on the winch drum 3 and an upward force on the load cell 5. Therefore, the belt tension F measured by the load cell 5 is highly dependent on the tension P of the mooring cable 11.

[0029] When moored, the mooring cable 11 hanging on the mooring bollards on the dock is wound around the winch drum 3 by the prime mover 22, and the band brake 4 is locked, and the clutch 24 is closed.

[0030] Furthermore, such as Figure 2 As shown, the mooring cable tension monitoring system 1 includes a layer count detector 6 that detects the number of layers of mooring cable 11 on the winch drum 3, and a control device 8 electrically connected to the layer count detector 6 and the aforementioned weighing sensor 5. The control device 8 is also electrically connected to a display 9. The display 9 is located, for example, near the winch, on the bridge, or in the loading / unloading control room (cargo control room).

[0031] For example, the control device 8 is a computer with memory such as ROM and RAM, storage such as HDD and SSD, and a CPU, and the program stored in ROM or storage is executed by the CPU.

[0032] The layer count detector 6 includes a sensor that measures a value related to the layer count of the mooring cable 11 and a calculation unit that converts the value measured by the sensor into the layer count of the mooring cable. The calculation unit may also be assembled in the control device 8. In this embodiment, the sensor that measures a value related to the layer count of the mooring cable 11 is an encoder 61 that measures the rotation angle of the winch drum 3.

[0033] More specifically, the encoder 61 is disposed on a sprocket tooth located away from the winch drum 3, and a chain is mounted on the sprocket tooth and the sprocket tooth mounted on the winch drum 3.

[0034] The control device 8 calculates the tension P [kN] acting on the mooring cable 11 based on the number of layers N of the mooring cable 11 detected by the layer number detector 6 and the belt tension F [kN] measured by the weighing sensor 5. The control device 8 outputs the calculated tension P to the display 9.

[0035] Specifically, the control device 8 calculates the tension P acting on the mooring cable 11 using the following tension calculation formula (1), which includes the tension coefficient K and the correction coefficient α:

[0036] [Mathematical formula 1]

[0037] ,

[0038] D B Brake drum diameter [mm]

[0039] d R : Mooring cable diameter [mm]

[0040] d D : Winch drum diameter [mm].

[0041] The tension coefficient K in the tension calculation formula (1) is calculated using the following formula (2):

[0042] [Mathematical Expression 2]

[0043] ,

[0044] μ: Coefficient of friction between the belt and the brake drum;

[0045] θ: Contact angle between the belt and the brake drum;

[0046] Additionally, the contact angle θ between the belt and the brake drum is as follows: Figure 3 The angle between the centers of pins 45 and 46 is shown in the figure.

[0047] Regarding the correction coefficient α in the tension calculation formula (1), the cable tension monitoring system 1 is as follows: Figure 2 The diagram includes a correction device 7. The control device 8 sets the correction coefficient α to 1.0 in the initial state.

[0048] When not moored, the calibration device 7 is used to confirm the relationship between the belt tension F of the belt brake 4 and the hypothetical tension Pv of the mooring cable 11 at the rated number of layers Nr. The rated number of layers Nr is arbitrarily determined, for example, between 1 and 3 layers.

[0049] Specifically, the calibration device 7 includes: a triangular connecting rod plate 71 that is non-rotatably connected to the flange 31 and protrudes laterally from the flange 31; a jack 72 (hydraulic cylinder) that moves the tip of the connecting rod plate 71 up and down; and a hand pump 73 connected to the jack 72 via a hose 74. The pressure Pr of the working fluid pressurized by the hand pump 73 is measured by a pressure sensor 75. Furthermore, the structure of the calibration device 7 is not limited to this and can be modified appropriately.

[0050] When not moored, with the hand pump 73 operated while the belt brake 4 is engaged, working fluid is supplied to the jack 72 via the hose 74, causing the jack 72 to extend. As the jack 72 extends, the belt tension F of the belt brake 4, measured by the load cell 5, increases. The control device 8 calculates the hypothetical tension P of the mooring cable 11 using the following formula (3). v [kN]:

[0051] [Mathematical Expression 3]

[0052] ,

[0053] P r Pressure sensor 75 measures the pressure [MPa].

[0054] L: Distance from the center of winch drum 3 to the center of jack 72 [mm];

[0055] A S The pressure-bearing area on the head side of the hydraulic cylinder of jack 72 [mm] 2 ];

[0056] D r The diameter of the center circle of the surface mooring cable is the rated number of layers Nr.

[0057] D r =d D +N r ×d R .

[0058] Based on the results confirmed by the calibration device 7, the control device 8 determines the calibration coefficient α. The results confirmed by the calibration device 7 show that the calibration coefficient α sometimes remains at 1.0, and sometimes is less than or greater than 1.0.

[0059] More specifically, when the control device 8 calculates the imaginary tension Pv of the mooring cable 11 using equation (3), it substitutes the belt tension F measured by the weighing sensor 5 into the above equation (1) so that the tension P calculated by equation (1) is consistent with the imaginary tension Pv of the mooring cable 11 calculated by equation (3) to determine the correction coefficient α.

[0060] As explained above, in the mooring tension monitoring system 1 of this embodiment, the number of layers N of the mooring cable 11 on the winch drum 3 is detected by the layer count detector 6. Therefore, instead of keeping the radius from the center of the winch drum 3 to the line of action of the tension constant, the tension P of the mooring cable 11 can be calculated using the number of layers N. Thus, the tension P of the mooring cable 11 during mooring can be monitored without the separation drum. Furthermore, the calculated tension P is output from the control device 8 to the display 9, so the crew member viewing the display 9 can grasp the tension P of the mooring cable 11.

[0061] Additionally, when the tension P of the mooring line 11 exceeds the specified value, the control device 8 causes the alarm (not shown) to sound, and the crew member who hears the alarm releases the band brake 4. As a result, the mooring line 11 becomes unwinding. Subsequently, the crew member opens the clutch to wind the slack mooring line 11 onto the winch drum 3, and then locks the band brake 4 to close the clutch 24.

[0062] (Modified example)

[0063] This invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of this invention.

[0064] For example, the sensor that measures the number of layers of the tether cable 11 related to the layer count detector 6 is not limited to the encoder 61 that measures the rotation angle of the winch drum 3. For example, such as Figure 4 As shown, when the mooring cable 11 is pressed against the pressing member 32 of the winch drum 3 and is configured to rock around the fulcrum 33, the sensor that measures the value related to the number of layers of the mooring cable 11 in the layer number detector 6 can also be an encoder 62 (or a tilt sensor) that measures the angle of the pressing member 32.

[0065] Or, such as Figure 5 As shown, when the mooring cable 11 is pressed against the pressing member 33 of the winch drum 3 in a reciprocating configuration, the sensor that measures the number of layers of the mooring cable 11 related to the number of layers detected by the layer number detector 6 can also be a stroke sensor 63 that measures the position of the pressing member 33.

[0066] In addition, the layer count detector 6 can also use a camera to directly detect the layer count of the mooring cable 11 on the winch drum 3. Or, as... Figure 6As shown, the roll count detector 6 can also directly detect the roll count of the mooring cable 11 on the winch drum 3 using the infrared unit 64 provided on the flange 31. When using the infrared unit 64, the height of the mooring cable 11 from the deck 10 at a specified position between the mooring metal part (e.g., the guide roller for the mooring cable 11) and the winch drum 3 can be measured by the infrared unit 64, and this height can be converted into the roll count.

[0067] Furthermore, the correction device 7 can be omitted, and the tension calculation formula (1) may not include the correction coefficient α. However, if the correction device 7 is provided as described in the embodiment, and the correction coefficient α in the tension calculation formula (1) is determined by using the confirmation result of the correction device 7, the tension P of the mooring cable 11 can be calculated correctly.

[0068] Furthermore, in the described embodiment, the band brake 4 is manual, but it can also be electric. In this case, if the tension P of the mooring line 11 calculated by the control device 8 exceeds a predetermined value, the control device 8 can also release the band brake 4. Also, if the band brake 4 is electric, and the clutch 24 is also electric, the control device 8 can disengage the clutch 24 after the band brake 4 is released, allowing the slack mooring line 11 to be wound onto the winch drum 3. This structure is useful for reducing crew manpower and for automated navigation.

[0069] Also, such as Figure 7 As shown, the pin-type load cell 5 assembled on the belt brake 4 can be a pin 49 located between the support 12 and the linkage mechanism 47 on the deck 10. At this time, the control device 8 calculates the tension P acting on the mooring cable 11 using the tension calculation formula (4) below:

[0070] [Mathematical Expression 4]

[0071] ,

[0072] L: Horizontal distance from the center of winch drum 3 to the center of pin 49 [mm].

[0073] (Summarize)

[0074] The mooring cable tension monitoring system of the present invention is characterized by comprising: a winch drum for winding the mooring cable; a belt brake including a brake drum that rotates together with the winch drum; a roll number detector for detecting the number of rolls of the mooring cable on the winch drum; a weighing sensor assembled to the belt brake for measuring belt tension; and a control device for calculating the tension acting on the mooring cable based on the number of rolls of the mooring cable detected by the roll number detector and the belt tension measured by the weighing sensor.

[0075] Based on the above structure, the number of layers of the mooring cable on the winch drum is detected by a layer count detector. Therefore, instead of keeping the radius from the center of the winch drum to the line of action of tension constant, the tension of the mooring cable can be calculated using the number of layers. Thus, the tension of the mooring cable during mooring can be monitored without a separation drum.

[0076] Alternatively, the control device can output the calculated tension to a display. With this configuration, the crew member viewing the display can monitor the tension of the mooring lines.

[0077] Alternatively, the aforementioned mooring cable tension monitoring system may also include a correction device for confirming the relationship between the belt tension of the belt brake and the hypothetical tension of the mooring cable at the rated number of coils when not moored. The control device calculates the tension acting on the mooring cable using a tension calculation formula including a correction coefficient, and determines the correction coefficient based on the result confirmed by the correction device. With this structure, the tension of the mooring cable can be calculated accurately.

[0078] Symbol explanation:

[0079] 1. Mooring cable tension monitoring system;

[0080] 11 Mooring rope;

[0081] 3. Winch drum;

[0082] 4. Band brake;

[0083] 41. Brake drum;

[0084] 5. Weighing sensors;

[0085] 6-layer count detector;

[0086] 7. Calibration device;

[0087] 8. Control device;

[0088] 9. Monitor.

Claims

1. A mooring cable tension monitoring system, comprising: A winch drum for winding the mooring cable; A band brake comprising a brake drum that rotates together with the winch drum; A layer count detector for detecting the number of layers of the mooring cable on the winch drum; A weighing sensor assembled on the belt brake to measure belt tension; A control device that calculates the tension acting on the mooring cable based on the number of mooring cable layers detected by the layer number detector and the belt tension measured by the weighing sensor. and A correction device for confirming the relationship between the belt tension of the belt brake and the hypothetical tension of the mooring cable at the rated number of coils when not moored, the correction device comprising a connecting rod plate non-rotatably connected to the flange of the winch drum, a hydraulic cylinder, i.e., a jack, for moving the connecting rod plate up and down, and a hand pump connected to the jack via a hose. The control device calculates the tension acting on the mooring cable using a tension calculation formula that includes a correction factor, and determines the correction factor based on the result confirmed by the correction device.

2. The mooring cable tension monitoring system according to claim 1, characterized in that, The control device outputs the calculated tension to the display.

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