JPH04223996A - Automatic wave follow-up device - Google Patents

Abstract

PURPOSE:To improve the wave follow-up property of a sling before the sling is connected to an object to be lifted such as a buoy or the like on the sea. CONSTITUTION:The upper terminal of a load cell 1 is connected to a part which makes a movement same as that of the hook 9 of a crane 7 operating on the sea, and at the same time, the lower terminal of the load cell 1 is connected to a wave detecting chain 2 which achieves free movement to follow up the wave motion. The constitution is characterized in such a way that a controller 4 is provided to perform an automatic control of the hoisting winch 6 of the crane 7 so as to hold the detected values from said load cell 1 to predetermined levels.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic wave following device that is applied to a crane installed on a ship or on land, for example, when lifting a buoy or the like on the ocean.

0002

2. Description of the Related Art Conventionally, constant tension devices using hydraulic cylinders, pneumatic cylinders, etc. have been used to lift objects that are susceptible to the effects of waves.

0003

[Problems to be Solved by the Invention] However, since such a constant tension device operates after the hanging rope is connected to the object, it becomes difficult to sling the hanging rope to the object. On the other hand, if there is no connection with the object to be lifted, non-contact detection devices such as optical sensors or ultrasonic sensors that detect the displacement of the object due to waves may be considered, but the method of installing the sensor is difficult and the detection range is limited. Limited and not suitable for practical use.

The present invention has been developed in view of the current situation, and is capable of detecting the displacement of an object to be lifted using a load cell, so that the suspension rope can be reliably connected by following the fluctuations of the object. The purpose is to

[0005]

[Means for Solving the Problems] The structure of the present invention for achieving the above object will be explained with reference to FIGS. 1 and 2, which correspond to embodiments. A load cell 1 that is connected to a part that moves in the same way as the hook 9 and whose lower end is connected to a wave detection chain 2 that can freely move to follow the movement of waves to detect tension fluctuations in the wave detection chain 2; The present invention is characterized by comprising a controller 4 that automatically controls the hoisting winch 6 of the crane 7 so as to maintain the detected value at a constant value.

[0006]

[Operation] According to the above-mentioned means, when the object to be lifted is lowered by waves, the crane hook, the load cell, and the chain do not move, so the chain is in the same state as if it had been lifted, and the load on the load cell becomes heavy. Furthermore, when the object to be lifted rises due to waves, the lower part of the chain is lifted by the object to be lifted, so the load on the load cell becomes lighter.

[0007] Therefore, if the hoisting winch of the crane is controlled so that the output load of the load cell is constant, the relative position of the crane hook and the object to be lifted can be controlled to be constant.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In FIGS. 1 and 2, reference numeral 7 denotes a crane erected on the deck 11 of the work boat, and a hanging rope 20 extended from the winch 6 suspends a hook 9 via a balance 21. 2 is a wave detection chain having an upper end connected to a relay wire 22 suspended from the balance 21 and a stabilizing weight 23 attached to the lower end, and having a length of about 1 m and a weight of 6 kg.

Reference numeral 1 denotes a load cell installed on the relay wire 22, the output of which is guided to the controller 4 of the crane 7 through a cable 10 and a brushed cable reel 3. Reference numeral 5 denotes a starter panel, which rotates the winch motor 6 in the forward and reverse directions according to commands from the controller 4, and controls the balance 2.
Raise and lower 1.

Reference numeral 8 indicates an object to be lifted, such as a buoy, which is lifted by the crane 7, and is moving unrelated to the work boat 11 due to waves. In the above, load cell 1 is 3k
g, and the controller 4 is set to send a hoisting signal to the winch 6 in a range exceeding 3±0.5 kg. Thus, as shown in FIG.
g) by transmitting signals for hoisting and unwinding the crane suspension line 20 to the winch starter panel 5 and operating the winch motor 6, the load applied to the load cell 1 is controlled within a certain range (for example, 3±0.5 kg). ). In other words, the chain connected to the load cell follows the movement of the buoy so that about half of its own weight (6/2=3 kg) is kept lying on the top surface of the buoy 8. As a result, the crane hook 9 follows the movement of the buoy 8 and is positioned near the lifting eye bolt 24 provided on the top surface of the buoy, thereby facilitating the slinging operation.

[0011]

[Effects of the Invention] According to the present invention, the upper end is connected to a part that moves in the same way as the hook of a crane working on the sea, and the lower end is connected to a wave detection chain that has free movement to follow the movement of waves. It is equipped with a load cell that is connected to detect the tension fluctuation of the wave detection chain, and a controller that automatically controls the hoisting winch of the crane so as to maintain the detected value of the load cell constant. Since displacement caused by waves can be interpreted as a change in the load on the chain, it has the effect of being able to follow waves even before the object to be lifted and the crane's suspension line are connected.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an automatic wave tracking device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing how the wave detection device is attached.

FIG. 3 is an explanatory diagram showing the operating state of the chain.

[Explanation of symbols]

1 Load cell 2 Wave detection chain 4 Controller 6 Hoisting winch 7 Crane 9 Hook

Claims (1)

[Claims] [Claim 1] The upper end is connected to a part that moves in the same way as the hook of a crane working at sea, and the lower end is connected to a wave detection chain that has free movement to follow the movement of waves, so that the tension of the wave detection chain can be adjusted. An automatic wave following device comprising: a load cell that detects fluctuation; and a controller that automatically controls a hoisting winch of the crane so as to maintain a detected value of the load cell at a constant value.