JPH06329392A - Posture holding method and device for vessel on lifter - Google Patents

Abstract

PURPOSE:To reduce work personnels, and shorten necessary time by fixing wires of respective winches arranged on both side of a lifter to a vessel, rewinding the wires according to a rise of the vessel by the lifter, measuring tensile forces of the respective wires and keeping them equal to each other when a posture is held, and keeping a difference in a rewinding length between the wires below an allowable value. CONSTITUTION:A vessel S enters a dock in a condition where a platform 10 of a lifter and a carriage 7 above it are lowered, and the tips of wires 11a-14a of respective winches 11-14 are fixed to bollards 6 of the vessel S. After centering is performed by operation of the winches 11-14, they are set in automatic tension, and a zero point to display a wire rewinding length is adjusted, and an allowable value is set. The lifter is operated, and the vessel is raised, and a hydraulic motor 20 is controlled so that tensile forces of the wires are equalized to each other by respective tension gauges 17, and the wires 11a-14a are rewound by the respective winches 11-14. At the same time, the rewinding length is measured by a length detecting device, and a difference in the rewinding length is held and controlled below an allowable value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is designed to properly position a ship when it is mounted on a platform of a lifter and lifted in the process of transporting a ship on the surface of the water to the sill of a shipyard for repair or the like. Retention method and apparatus.

[0002]

Conventionally, for example, a synchro lift (trade name)
In order to lift the ship to be lifted with a lifter, etc. in a correct posture, winch wires arranged on both sides of the lifter were fixed to the ship, and those wires were unwound as the ship lifted. . FIGS. 6 and 7 show such a conventional device, in which 1 is a lifter, on each side of which there is at least one pair of winches 2 and therefore on both sides at least two pairs of winches 2, Three, four and five were placed. The tips of the wires 2a, 3a, 4a, 5a of each winch are fixed to the bollard 6 of the ship. The ship S is mounted on a dolly 7 placed on a lifter platform 1a. Reference numeral 8 is a vertical rail, and the vertical rail is aligned with the rail on the platform by the rise of the platform 1a, and in this state, the ship is placed on the vertical rail with the carriage 7. Be moved.

Although not shown in the drawing, the platform 1a is constructed so as to be lifted by a series of lift winches arranged on the left and right sides of the platform 1a. When mounting the ship, the platform 1a is mounted on the platform 7a.
With the ship set, the ship descends below the surface of the water, and the ship is docked on it, and the winches 2, 3, 4, and 5 are fixed to the bollards of the ship. The operator arranged operates the winch in charge to adjust the wire while tensioning or loosening the wire to position and fix the ship at the center of the carriage 7. Each winch was operated by each worker so that the ship would not tilt to the left or right when the ship was raised.

[0004]

[Problems to be Solved by the Invention] Trim (tilt) on a ship
Therefore, when lifted by the lifter, either the bow or the stern comes into contact with the dolly first, and the opposite side easily swings to the left or right, making it difficult to center and stabilize the ship. However, in the prior art, even if each winch is of the power-driven type, it is considerably necessary to position the ship at the expected position on the trolley and to climb the ship while maintaining the correct posture, because each winch was operated by each operator. It required a lot of experience and skill, and required a relatively large number of workers, and in addition, it took a relatively long time to carry over the ship. In addition, it was difficult to maintain the correct attitude of the ship.

An object of the present invention is to eliminate the above-mentioned problems of the prior art. Therefore, it is possible to reduce the number of workers required for overhead work and shorten the time required, and to maintain the correct posture of the ship. It is an object of the present invention to provide a method for maintaining the attitude of a ship on a lifter and an apparatus used for carrying out the method, which can be lifted upright.

[0006]

According to the method for maintaining the posture of a ship according to the present invention, the wires of the winches arranged on both sides of the lifter are fixed to the ship and the wires of the winches are rewound as the ship rises. It is characterized in that the wire of each winch is unwound while the tension of each wire is equalized and the difference in the unwinding length between the wires is kept below an allowable value.

Further, the ship attitude holding device according to the present invention includes at least two pairs of winches arranged on both sides of a lifter for raising a ship to be mounted, and the wires of each winch are fixed to the ship to secure the ship's attitude. Each winch is configured to rewind each wire as it rises, each winch is driven by a hydraulic motor to adjust the tension of the wire, and a tensiometer for measuring the wire tension of each winch and each It is characterized by including a length detection device that measures the unwinding length of the wire.When the unwinding length of the wire exceeds a permissible value, the tension of the wire is adjusted and the unwinding length is adjusted again. Allows to be equal.

[0008]

According to the method of the present invention, when the lifter lifts the ship, the tension of the winch wires holding the ship is kept equal, and the unwinding lengths of the winch wires are equalized. As the wire is unwound, the ship is raised with the correct attitude set at the beginning. If the difference between the unwinding lengths of the wires during the ascending process of the ship exceeds the allowable value, the winch is adjusted so that the difference becomes less than the allowable value.

Further, in this apparatus, when the ship is lifted by the lifter, the tension of each winch wire is constantly measured by a tensiometer to keep the tension of each wire equal, and at the same time, the unwinding length of each wire is adjusted. It is measured and the difference is kept below an allowable value. If the ship tilts slightly even when rising, the tilt is detected as a difference in the unwinding length between the left and right wires of the ship.In that case, the tension of the wire on the less unwinding side is weakened by operating the winch, Then, when the difference in the unwinding length is restored to the allowable value or less, the tensions are made equal again.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 illustrates a lifter equipped with a device used for carrying out the method of the present invention. It includes a platform 10 on which a ship S is mounted and the platform 10 on both sides of the platform. A lifter consisting of a lift winch (not shown) is provided with winches for holding the ship on both sides. As the winches, at least two pairs of winches are provided in a well-balanced manner, and therefore, a pair of winches 11 is provided on one side.
A pair of winches 13, 14 are provided on 12 and on the other side. To hold the ship on the platform, the tips of the wires 11a, 12a, 13a, 14a of each winch are fixed to the bollard 6 of the ship. Further, in the middle of each wire, a pulley 15 as a guide and a fixed pulley 16 are provided.
Are placed.

The method of maintaining the attitude of a ship according to the present invention is a lifter.
Is characterized in that the tension of each wire to be unwound when climbing a ship is equalized, and the unwinding length of each wire is kept substantially equal, so that the unwinding of the wire is performed, and therefore, it is associated with each winch or its wire. A tension meter 17 such as a load cell for measuring the tension of the wire and a wire length detector 18 for measuring the rewinding length of the wire (FIG. 2)
Is installed. This tensiometer 17 and length detector 18
As shown in the drawing, each winch or each wire is provided, and their outputs (detection values) are sent to the control chamber 19.

Each winch, as shown in FIGS. 2 and 3, is provided with a hydraulic motor 20 and is driven by the hydraulic motor to apply a predetermined tension to each wire and adjust the tension. It Preferably each winch has the same configuration. In this example, each winch has a drum 21 around which a wire is wound and a gear 22 fixed coaxially with the drum, as shown in the drawing.
And a pinion 23 meshing with the gear, and the hydraulic motor.
A pinion 23 is fixed to the main shaft of the hydraulic motor. Reference numeral 24 is an emergency manual brake, the brake drum 25 of which is fixed coaxially with the drum 21, and an appropriate number of brake shoes 26 are provided around the brake drum 25.

Further, in this example, the length detecting device 18 provided in each winch is connected to the shaft of the drum 21 by a chain 27, and the rotating speed and the rotating angle of the drum 21 are detected by the synchronizing generator in the detecting device. By doing
The length of the wire that is unwound or unwound is measured. The winch drum 21 is preferably constructed as a single layer winding to accurately measure the length of the wire.

Each winch is adapted to adjust the tension applied to the wire by adjusting the pressure of the hydraulic oil of its hydraulic motor 20, which pressure is provided to the hydraulic motor. The pressure of a hydraulic pump such as a variable piston pump is adjusted by operating an appropriate operating valve or a ship valve. This operating valve can be operated by remote control from the control room or by potentiometer command of the portable box.

A variable piston pump is preferably used to apply an auto tension (automatically adjusted tension) to the wire, and the pump discharges a required amount of hydraulic oil to perform a constant pressure holding control. The tension applied to each wire varies depending on the size and shape of the ship, but the hydraulic motor for each winch 2
It is operated by setting the hydraulic pressure introduced to 0 with an adjusting valve such as an electromagnetic proportional relief valve, and the adjusting valve is operated with an electromagnetic proportional remote controller or the like.

The tensiometer 17 is installed between each winch and its corresponding fixed pulley 16 as shown in FIG. 1, and as shown in FIG. 4, a shaft or pipe 29 in which a universal joint 28 is interposed. Is connected to the fixed pulley 16 by means of which the tensiometer 17 is at the position of the wire stretched between the winch and the pulley.

A strain gauge type load converter is preferably used for the detecting portion of the tensiometer 17, and the sensing member thereof is provided with a Wheatstone bridge including a strain gauge, and the input end of the bridge. When a constant voltage is applied to, an output voltage proportional to the load is generated at the output end. The output voltage is amplified and used as a control output.

When the ship to be overridden docks with the platform 10 of the lifter and the dolly 7 on it lifted down, the winches 11, 12, 13, on both sides of the ship,
The wires are unwound from 14, and the tip of each wire is fixed to the bollard 6 or the like on the main deck of the ship. When positioning the ship in the center of the lifter, the conductor usually gives visual instructions to the operator in the control room by radio, and the operator operates each winch by remote control without auto-tension. To center the ship.

As shown in FIG. 5, once the ship is centered, it is secured by the appropriate wire tension on each winch. Each wire is then transferred to autotension, for example by pressing an autotension pushbutton. The adjustment of the autotension of each wire is performed by changing the setting of the control valve, and in one example, each wire is loaded with 5 ton of autotension. Then, the display of the rewinding length of each wire is adjusted to 0 point, and the allowable value ΔT of the difference between the rewinding lengths is set by the comparator amplifier. This tolerance is 80 mm in one example.

After the same tension is applied to the wires of each winch and the zero point of each wire is adjusted in this way, the lifter is operated to raise the ship. The wire of each winch is unwound as the ship rises, with the unwinding force of each wire being greater than the force of the winch hydraulic motor 20 winding the wire onto the drum 21, and hence the hydraulic motor. Ta rotates in the reverse direction. Therefore, a constant hydraulic pressure (5 tons in the above example) that attempts to rotate the hydraulic pump is applied to the wire as a braking force.

Further, the rewinding length L of the wire of each winch is detected along with the operation of the lifter, and the difference ΔL in the rewinding length between the wires, especially between the right and left wires, is always the difference between the lengths. Is compared with the allowable value ΔT of And the difference Δ
If L is less than or equal to the allowable value, it is confirmed that the ship maintains a normal posture without tilting.

If the difference ΔL in the unwinding length exceeds the allowable value, that is, in the above example, when it exceeds 80 mm, it indicates that the ship is tilted, and in that case, the lifter remains in the operating state and the winding is performed. Hydraulic motor 20 for winch on the side with short return length
Is weakened by the differential pressure adjusting volume, for example, half the initial tension, 2.5 tons in the above example, to restore the attitude of the ship. That is, as the ship ascends, the unwinding length of the wire on the weaker tension side becomes larger than the unwinding length of the other wires, and the difference in the unwinding length between the wires again becomes less than the allowable value. The tensions of the wires are equalized when the wire tension falls below the allowable value. It should be noted that such an operation can be performed automatically by an appropriate controller.

In the above example, the allowable value ΔT is set to 80 mm, and when it exceeds the allowable value ΔT, it is assumed that the ship is tilted. However, the tilt in this case does not mean that the ship is overturned or the like, but it does not mean that the ship is overturned. It means that it is out of the set tolerance. In the above experimental examples, when the allowable value is 80 mm, the difference in the unwinding length between the wires exceeds only 1 to 2 percent. It should be noted that the occurrence of a situation in which the allowable value is exceeded can be confirmed visually by a tensiometer or at that time by hearing a flicker sound by a flicker sound generated by a comparator amplifier.

Thus, with the tension of each wire kept constant and each unwinding length kept equal, the ship ascends, and when the upper limit of the lifter platform is reached, the lifter stops and the platform The rails on the form are aligned with the vertical rails 8. In the above example, the allowable value is set to 80 mm, but it goes without saying that the value is appropriately selected depending on the size of the ship to be overloaded and other conditions. Also,
The optimum number of winches arranged on both sides of the ship is used according to various conditions or specifications. Furthermore, it is clear that the method and the device can be applied as well when descending a ship to the surface of the water.

[0025]

As described above, according to the present invention, when the ship is raised, the tensions of the winch wires for holding the ship are kept equal and the rewind lengths of the wires are made approximately equal. Being rewound, the ship can be lifted in the correct position. Further, in the device of the present invention, it is possible to surely hold the tension of the wires of each winch to be the same and to make the rewinding lengths equal, which is highly reliable. Further, even if the ship is slightly tilted during the ascent of the ship, it can be immediately restored by operating the tension of the wire. Therefore, it is possible to carry out the work of hoisting the ship in a relatively short time, and it is possible to operate the operator after fixing the wire to the ship, which saves a great deal of labor.

[Brief description of drawings]

FIG. 1 is a plan view generally showing an example of a boat attitude holding device according to the present invention.

FIG. 2 is a plan view showing an example of a winch used in the device of the present invention.

3 is a side view of the winch shown in FIG. 2. FIG.

FIG. 4 is a cross-sectional view showing an example of a tensiometer used in the device of the present invention.

FIG. 5 is a flow chart schematically showing the method of the present invention.

FIG. 6 is a plan view generally showing a conventional attitude holding device for a ship.

7 is a cross-sectional view of the conventional example of FIG.

[Explanation of symbols]

 11 winch 12 winch 13 winch 14 winch 17 tensiometer 18 length detector 20 hydraulic motor

Claims (2)

[Claims] 1. A wire for each winch arranged on both sides of a lifter for lifting a ship to be mounted is fixed to the ship, and the wire for each winch is rewound as the ship is lifted by the operation of the lifter. In the method of properly maintaining the attitude of the ship, the tension of each of the wires is measured, the tensions of the wires are kept equal, and the difference in the unwinding length between the wires is kept below an allowable value. A method for maintaining the attitude of a ship on a lifter, characterized by performing return. 2. Including at least two pairs of winches disposed on opposite sides of a lifter for raising a ship to be overloaded, the wires of each winch being secured to the ship and of each winch as the ship is elevated. In the posture maintaining device of the ship, wherein the wire is rewound, each winch is driven by a hydraulic motor to adjust the tension of each wire, and the tension of the wire of each winch is further adjusted. A posture maintaining device for a ship on a lifter, comprising: a tension meter for measuring; and a length detecting device for measuring a rewinding length of a wire of each winch.