JPH0316923Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a drag head structure suitable for use in a drag suction dredger or the like.

[Conventional technology]

Generally, a drag suction dredger has a mud hold 2 in a hull 1, as shown in FIG. 4, and performs dredging work while pulling a drag head 4 with a drag arm 3.

There are various types of drag head 4,
When the bottom of the water is hard and compact, a drag head 4 equipped with a rotary cutter 8 as shown in FIG. 5 is conventionally used. Such a drag head 4 has a suction mouth 5 and a drag head case 6 attached thereto, and is connected via a flange 11 to a drag arm 3 shown in FIG.

In FIG. 5, reference numeral 7 indicates a motor for driving the rotary cutter, 10 a sled for sliding the drag head along the seabed 9, and 13 a hinge.

[Problem that the invention attempts to solve]

However, in the conventional drag head structure as described above, the drag head 4 is equipped with a drive motor 7,
Since it is necessary to equip the cutter shaft and the cutter 8 (not shown), there is a problem in that the weight increases, the traction resistance during dredging increases, and the propulsion resistance of the hull 1 increases.

Therefore, if the propulsion power of the hull 1 is insufficient, it may become impossible to tow at a predetermined speed.

Furthermore, since the force acting on the drag head 4 changes depending on the speed of the towing wall, when the towing speed is increased, the front part of the drag head 4 rises and the excavation depth 12 increases, as shown in FIG. It becomes shallow. In other words, since the drag head 4 is being pulled by the drag arm 3, it receives a pulling force in the axial direction of the drag arm 3, and not only receives a horizontal force from the drag arm 3, but also receives a vertical upward force. There is also the problem that the front part of the drag head 4 lifts up due to the force, resulting in a decrease in dredging efficiency.

In order to prevent such lifting of the drag head 4, it is conceivable to add a counterweight to the front of the drag head 4, for example near the position of the hinge 13, to increase resistance to lifting at the front of the sled 10. This is disadvantageous because the weight of the vessel 4 further increases, leading to an increase in the propulsion resistance of the hull 1.

The present invention attempts to solve these problems by reducing the underwater weight of the drag head and appropriately changing the weight distribution in the front and rear directions as necessary. To provide a drag head structure for a dredger which prevents the front part of the drag head from floating and enables efficient dredging.

[Means for solving problems]

For this reason, the drag head structure of the dredger of the present invention is provided with a drag head consisting of a cutter and a case covering the cutter at the tip of a drag arm whose base end is pivotally supported by the ship's hull, and the case is formed into a double structure. At the same time, a partition wall is provided to partition the internal space of the case, and a plurality of compartments divided by the partition wall are distributed in the front and rear direction, and piping for injecting and discharging ballast water is installed in each of these compartments. It is characterized by being connected.

[Effect]

In the drag head structure of the dredger described above, the underwater weight of the drag head can be reduced by draining the ballast water from each compartment in the internal space of the case, but it is also possible to inject ballast water into the appropriate compartments. Therefore, lifting of the front part of the drag head can be prevented.

〔Example〕

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.
FIG. 2 is a side view showing a drag head structure of a dredger as an example.

The first embodiment will be explained with reference to FIG.
A drag head 4' is provided at the tip of a drag arm 3 (see FIG. 4) that is pivotally attached to the hull 1. This drag head 4' has a rotary cutter 8
And this cutter 8 and the drag head case 6 that covers it.
and a case 16 that further covers the drag head case 6 to form a double structure. In FIG. 1, reference numeral 5 indicates a suction mouse, 7 indicates a drive motor for a rotary cutter 8, 9 indicates a seabed, and 10 indicates a sled.

The internal space between the case 16 and the drag head case 6 is partitioned by a plurality of partition walls 15 and divided into a plurality of watertight compartments 14a to 14f distributed in the front-rear direction. Pipes (not shown) for injecting and discharging ballast water are connected to these sections 14a to 14f, respectively, so that ballast water can be injected and discharged independently.

Since the drag head structure of the dredger according to the first embodiment of the present invention is constructed as described above, the drag head 4' discharges the ballast water in the compartments 14a to 14f of the case 16 when the front part is not floating. This increases the buoyancy of the drag head 4' and significantly reduces its underwater weight.

In addition, if the towing speed increases and the front part of the drag head 4' is likely to lift up, or if it occurs, for example, ballast water is injected into the compartment 14a and the ballast water in the compartments 14b to 14f is discharged. If this is done, the front part of the drag head 4' becomes heavy, and the rear part becomes lighter due to increased buoyancy, thereby preventing the front part of the drag head 4' from floating up.

Furthermore, since the internal space is divided into a plurality of sections 14a to 14f distributed in the front and back direction,
Depending on the degree of floating of the drag head 4', ballast water can be selectively poured into the required sections to finely adjust the weight distribution of the drag head 4'. Therefore, a predetermined moment required to prevent floating can be obtained while minimizing an increase in the underwater weight of the drag head 4', and dredging work can always be carried out efficiently.

In the unlikely event that only the water inlet from each section 14a to 14f is used,
Even in cases where lifting of the front part of the drag head 4' cannot be prevented, a counterweight is added to the front part of the drag head 4', and ballast water is poured into an appropriate section so as to generate a buoyancy force at least equal to the weight of the counterweight. By discharging the drag head 4', without increasing the underwater weight of the drag head 4',
This makes it possible to increase the moment that resists lifting of the front portion of the drag head 4'.

On the other hand, the second and third embodiments of the present invention will be explained with reference to FIGS. 2 and 3. In these embodiments, cases 16' and 1 forming a double structure are used.
The only difference from the first embodiment is the shape of each 6", and the other parts are constructed almost the same as the first embodiment, and both embodiments have the same effects as the first embodiment. can get.

Note that the reference numeral 14 in FIGS. 2 and 3 indicates case 1.
6' and 16'' are divided by partition walls 15 into a plurality of compartments distributed in the front-rear direction.

[Effect of idea]

As described in detail above, according to the drag head structure of a dredger of the present invention, a drag head consisting of a cutter and a case covering the cutter is provided at the tip of the drag arm whose base end is pivotally supported by the ship body, and the drag head consisting of a cutter and a case covering the cutter is provided. is formed into a double structure, and a partition wall is provided to partition the internal space of the case.
It has an extremely simple configuration in which multiple compartments divided by the same bulkhead are distributed in the front and rear direction, and piping for injecting and discharging ballast water is connected to each of these compartments. While it is possible to reduce the underwater weight of the drag head, when the towing speed is increased, by adjusting the water inlet of the multiple sections distributed in the longitudinal direction mentioned above and finely adjusting the weight distribution of the drag head, the weight of the drag head can be reduced. Since the front part of the drag head can be prevented from floating without significantly increasing the weight underwater, dredging work can be carried out efficiently.

[Brief explanation of the drawing]

1 to 3 are side views showing the drag head structure of a dredger as the first to third embodiments of the present invention, FIG. 4 is a side view showing a drag suction dredger, and FIGS. 5 shows a drag head structure of a conventional dredger, FIG. 5 is a side view thereof, and FIG. 6 is a side view showing its front part in a floating state. 1...Hull, 2...Mud storage, 3...Drag arm, 4'...Drag head, 5...Suction mouse, 6...Drag head case, 7...Hydraulic motor, 8...Rotary cutter, 9...Undersea, 10...
...sled, 14, 14a-14f...section, 15...
...Bulkhead, 16, 16', 16''...Case.

Claims (1)

[Scope of utility model registration request] A drag head consisting of a cutter and a case covering the cutter is provided at the tip of the drag arm whose base end is pivotally supported by the hull, and the case is formed into a double structure, and a bulkhead partitions the internal space of the case. is provided, and a plurality of compartments divided by the same partition wall are formed so as to be distributed in the front and rear direction, and piping for injecting and discharging ballast water is connected to each of these compartments, Draghead structure of a dredger.