JPS6343256Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a drag head for a drag suction dredger, and particularly to an active type drag head suitable for use in dredging work on hard soil.

A conventional drag suction dredger, as shown in Figure 1, has a drag head 2 attached to the tip of a suction pipe 1 grounded to the water bottom 3, and uses a dredging pump installed inside the ship to draw suction and dredge while self-propelled. . The drag head 2 usually has a shape as shown in FIG. 2 (side view) and FIG. 3 (plan view), and the dredged soil 4 is scraped and dredged by claws 5 attached to the bottom surface of the drag head 2.

However, this method has the disadvantage that dredging becomes impossible when the seabed is hard.

In order to compensate for this drawback, a method called an active drag head has been developed. In this method, a cutter rotated by a motor is attached to the inside or outside of the drag head, and the cutter is used to scrape away the soil. Dredging is done by suctioning the clods of earth with a dredging pump.

4 and 5 show examples of conventional active type drag heads used in the above-mentioned means. The active drag head shown in Figure 4 is
Slide plate 2' is attached to the front,
This slide plate 2'
However, since the cutter 7 is fixed to the suction pipe 1 side, when the water depth changes, the cutter 7 becomes angled with respect to the submerged soil 4, reducing the excavation capacity. There is a problem. In the case of the drag head shown in Fig. 5, there is no mechanism to keep the excavated soil thickness constant, so the drag head 2 may penetrate too much into the soil.
In particular, there is a problem in that when there are irregularities on the bottom of the water, the influence becomes large.

The present invention aims to solve these problems by making it possible to stably excavate hard soil by keeping the excavation depth at an appropriate value in an active drag head equipped with a rotary cutter. The purpose is to provide a drag head with a

For this reason, the drag head of the present invention rotatably supports a rotating cutter via a cutter bearing, and is provided with a cutter cover consisting of a rotating cover and a fixed cover that cover the rotating cutter,
The fixed cover is fixed to the drag head,
The rotary cover is connected to the suction pipe so that its center of rotation is aligned with the center of the cutter bearing, and the drag head has a sled-shaped portion that curves upward from the front lower end of the fixed cover. It is characterized by the fact that it is formed.

Hereinafter, the drag head of the present invention will be explained with reference to the drawings. Figures 6 to 10 show a drag head as an embodiment of the present invention. Figure 6 is a side view, Figure 7 is a plan view, and Figure 8 is a side view of the drag head. The figure is a side view of the main part, FIG. 9 is a sectional view taken along the - arrow in FIG. 8, and FIGS. 10 a, b, and c are side views showing the operating state.

As shown in FIGS. 6 to 9, a cutter shaft 17 that drives the rotary cutter 7 is connected to a cutter bearing 18 fixed to the drag head 2 and a bush 1 for the cutter shaft.
A rotary cutter 7 supported by the drag head 2 seated on the seabed 3 is driven to excavate the underwater bed 4.

The cutter shaft 17 is connected to the cutter drive gear 2.
0, is connected to a drive motor 6 via a transmission cable 16, a transmission shaft bearing 9, and a drive shaft (transmission shaft) 19, so that the rotational force of the drive motor 6 is transmitted to the rotating cutter 7.

In addition, the transmission cable 16 and the cutter drive gear 20
is covered with a cover 10.

On the other hand, the rotating cutter 7 is covered with a cutter cover C consisting of a rotating cover 14 and a fixed cover 15.
The excavated soil is transferred to suction pipe 1.
It's starting to get sucked into.

By the way, the fixed cover 15 that constitutes a part of the cutter cover C is fixed to the drag head 2.

Further, the rotary cover 14 constituting the other part of the cutter cover C is supported by a cutter bearing 18 via a rotary cover bushing 21 at its lower part, and connected to the suction pipe 1 at its upper part.

The rotary cover bushing 21 is arranged so that its center coincides with the center of the cutter bearing 18, and the rotary cover 14 and the suction pipe 1 are located at the center of the cutter bearing 18 (the cutter drive shaft 17).
It is designed to be able to rotate around the center of rotation.

In addition, a connecting rod 12 is rotatably attached to the rear end of the fixed cover 15, and a stopper 11 is attached to the rear end of the rotating cover 14 and has a long hole 11a formed therein. The connecting rod 12 and the stopper 11 connect the rotating cover 14 and the fixed cover 15.
Stopper mechanism S that restricts the relative rotation range with respect to 5
is configured.

That is, an enlarged portion 12a is formed at the tip of the connecting rod 12, and this enlarged portion 12a is adapted to slidably engage with the elongated hole 11a of the stopper 11, so that when the rotating cover 14 rotates, the stopper 11 also rotates. Along with this, the connecting rod 12 also rotates around the base end 12b, and the enlarged portion 12a of the connecting rod 12 rotates around the elongated hole 1.
Move within 1a.

Then, when the rotating cover 14 rotates to the limit angle, the enlarged portion 12a moves to the end 11 of the elongated hole 11a.
b, 11c, the movement of the connecting rod 12 is stopped, thereby restricting the rotation of the rotating cover 14.

Note that the above-mentioned limit angle, that is, the rotating cover 1
The relative rotation range of No. 4 with respect to the fixed cover 15 is as follows:
It is set to allow a change in the attitude of the suction pipe 1 in response to a change in water depth.

Further, the fixed cover 15 has side portions 15a, 1 so that the cutter cover C as a whole can remain closed to the outside even when the rotating cover 14 rotates.
5b is extended.

Then, the fixed cover 1 on the drag head 2
A sled-shaped portion 2a is formed that curves upward from the lower end of the front side 15a of the drag head 2, and a sled-shaped portion 2b that curves upward is also formed at the rear end of the drag head 2. The attitude of the drag head 2 can be adjusted smoothly depending on the unevenness.

Since the drag head of the present invention is constructed as described above, in order to carry out dredging work, the suction pipe 1 is lowered by letting out the wire 22 as shown in Fig.
have them seated.

Then, as shown in FIGS. 6 to 9, the drive motor 6 is operated to rotate the rotary cutter 7, and the portion of the rotary cutter 7 protruding downward from the drag head 2 excavates the submerged soil 4 to a depth t. Then, the excavated soil is transferred to the ship through the cutter cover C and the suction pipe 1.

By the way, when the water depth becomes shallow, drag head 2
Since the ground pressure against the seabed 3 increases, this is detected on the ship, and the lifting wire 22 is fed onto the ship to lift the suction pipe 1.

At this time, the suction pipe 1 and the rotating cover 14 rotate clockwise in FIG. 6 with the center of the cutter bearing 18 as the rotation center, and the rotating cover 14 enters into the front part 15a of the fixed cover 15.

In this case, the attitude of the suction pipe 1 changes, but the attitude of the drag head 2 does not change, and excavation is performed by the portion of the rotary cutter 7 that protrudes downward from the drag head 2, and a constant excavation depth t is maintained. be done.

On the other hand, as the depth of the seabed 4 increases, the ground pressure of the drag head 2 against the seabed 3 decreases, so this is detected on board and the lifting wire 22
to lower suction pipe 1. At this time, the suction pipe 1 and the rotating cover 14 rotate counterclockwise in FIG. The dredging work will be carried out in this state. In this case as well, the attitude of the drag head 2 does not change, and the portion of the rotary cutter 7 protruding downward from the drag head 2 performs excavation, and a constant excavation depth t is maintained.

In addition, if the excavated soil 4 has unevenness, the first
It operates as shown in Figure 0 a, b, and c. That is, as shown in FIG.
The drag head 2 rotates around the cutter drive shaft 17 while the suction pipe 1 maintains a constant posture, and the excavated soil is removed. The attitude of the drag head 2 changes so as to follow the shape shown in FIG. 10B, and becomes the state shown in FIG. Then, the drag head 2 rides on the top 4b of the convex portion 4a, and the drag head 2 rotates in the opposite direction around the cutter drive shaft 17 to take a position along the top 4b. In this way, the excavation to the depth t is continued again in the state shown in FIG. 10c.

Further, even when approaching a recess, the posture of the drag head 2 is adjusted in the same manner as described above, and the excavation depth t is maintained constant.

In this way, even if there are irregularities in the excavated soil 4, the posture of the drag head 2 changes smoothly according to the shape, so the drag head 2 does not sink into the excavated soil 4, and the cutter 7 is prevented from being overloaded. This is avoided, and the action of excessive force on the suction pipe 1 is also avoided.

Note that when the water depth of the excavated soil 4 increases and reaches the limit depth, the enlarged portion 12a formed at the tip of the connecting rod 12 closes to the elongated hole 11a in the stopper 11.
The rotation cover 14 and the suction pipe 1 are restricted from rotating. In addition, when the water becomes shallow and cannot be dredged, when the drag head 2 is pulled out of the water and stored on board, or when maintenance is performed,
The enlarged portion 12a formed at the tip of the connecting rod 12 comes to be locked to the end 11c of the elongated hole 11a,
The attitude of the drag head 2 relative to the suction pipe 1 is maintained constant.

As detailed above, according to the drag head of the present invention, the drag head rotatably supports a rotating cutter via a cutter bearing, and includes a cutter cover consisting of a rotating cover and a fixed cover that cover the rotating cutter, and the fixed cover is fixed to the drag head, the rotating cover is connected to the suction pipe so that its center of rotation is aligned with the center of the cutter bearing, and the rotating cover is curved forward from the front lower end of the fixed cover. The simple structure in which a raised sled portion is formed has the following effects and advantages.

(1) The drag head will not sink into the underwater ground even if it is uneven.

(2) Since the excavation depth is constant, there is no overload on the cutter.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the working state of a dredger, Figs. 2 and 3 show a conventional drag head, Fig. 2 is a side view thereof, Fig. 3 is a plan view thereof, and Figs. Fig. 5 shows a conventional active type drag head, Fig. 4 is a side view showing one example thereof, Fig. 5 is a side view showing another example, and Figs. 6 to 10 show an embodiment of the present invention. Fig. 6 is a side view of the drag head, Fig. 7 is a plan view of the drag head, Fig. 8 is a side view of its main parts, and Fig. 9 is a side view of the drag head.
The figures are a cross-sectional view taken along the - arrow in Fig. 8, Fig. 10a,
b and c are side views showing the operating state thereof. 1... Suction pipe, 2... Drag head, 2
a, 2b... Warped portion of the drag head, 3... Seabed, 4... Submerged soil, 4a... Uneven portion of the submerged soil, 4
b...Top of the submerged soil, 5...Claw, 6...Drive motor,
7... Rotating cutter, 8... Rotating joint, 9... Transmission shaft bearing, 10... Cover, 11... Stopper, 11
a... Long hole, 11b, 11c... End of the long hole, 12...
Connecting rod, 12a... Enlarged portion of the connecting rod, 12b... Proximal end of the connecting rod, 13... Bush for the cutter shaft, 14
...Rotating cover, 15...Fixed cover, 15a...Front side part of fixed cover, 15b...Rear side part of fixed cover,
16...Transmission cable, 17...Cut shaft, 18...Cut bearing, 19...Drive shaft (transmission shaft), 20...Cut drive gear, 21...Bush for rotating cover, 22...Lifting wire, 23...Inboard rotation joint, C...
Cutting cover, S...stopper mechanism, t...excavation depth.

Claims (1)

[Scope of utility model registration request] A drag head that rotatably supports a rotating cutter via a cutter bearing is provided with a cutter cover consisting of a rotating cover and a fixed cover that cover the rotating cutter, the fixed cover being fixed to the drag head, and the rotating cover having a center of rotation. The drag head is connected to the suction pipe so as to be aligned with the center of the cutter bearing, and the drag head is formed with a sled-shaped portion that curves upward from the lower front end of the fixed cover. drag head.