JPH0111805Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a drag head used for port civil engineering work as a dirt suction and mud lifting device for a drag suction dredger. The present invention relates to a drag head with a digging blade that can be used in various ways.

The drag suction dredger that has been commonly used is the dredger a, as shown in Figures 1 and 2.
The drag arm (suction pipe) b protrudes from the side of the
A drag head c is attached to the tip of the drag arm b, and when the dredger moves forward by tilting the drag head c so that it touches the seabed surface d, a mixture of sediment and seawater on the seabed is activated by the dredging pump e inside the ship a. is sucked in by drag head c, and drag arm b,
It is designed to be loaded into a mud hold h of a dredger via a discharge pipe f and a loading trough g inside a ship a.

As shown in FIGS. 3 and 4, the drag head c used in the conventional drag suction dredger is box-shaped with an inlet i at the bottom, and when the dredger a moves forward. It is designed to draw a mixture of seabed sediment and seawater through the suction port i by being dragged along the seabed surface, and does not actively excavate the earth and sand.

Therefore, in the case of conventional dragheads, the target soil for dredging is limited to soft soil such as soft mud or unconsolidated fine sand or sand. Although such soft soil can be efficiently dredged, Since there is no ability to excavate fine sand, sand, clay, etc., there is a drawback that the dredging efficiency is significantly reduced.

In order to compensate for this drawback, a drag head j having a structure as shown in FIGS. 5 and 6 has conventionally been used. That is, an excavator blade drive shaft k is rotatably supported inside a drag head j, and excavator blades l extending in the longitudinal direction of the excavator blade drive shaft k are arranged radially on the outer surface of the excavator blade drive shaft k, and A drag head is used in which the excavating blade drive shaft k is rotated by a motor m, and the excavating blade l is rotated together with the excavating blade driving shaft k, thereby dredging earth and sand on the seabed.

This type of drag head with a digging blade currently in use uses a round-up excavation method that allows the excavated soil to be guided to a place where it can easily be sucked.
A method is adopted in which the dredger rotates in the opposite direction to the direction in which the dredger is traveling.

However, during dredging work in an area where there are many obstacles n such as rocks and waste in the seabed sediment, if the drilling blade l encounters an obstacle n, in the case of the above-mentioned round-up excavation method, the dredging The blade l actively cuts into the obstacle n or operates in the direction of digging deeper into the obstacle n, and the reaction force p exerted by the obstacle n on the digging blade l and the external force acting downward on the drag head, that is, the drag head The resultant force q of the external force o, which is the sum of the own weight and the adsorption force on the seabed caused by the dredging pump, is the drag arm b that is the suction pipe.
Therefore, it is necessary to provide sufficient strength to the drag head j, the drag arm b, and the joint between the hull and the drag arm b. Therefore, it has the disadvantage that it must be constructed as a heavy structure.

In order to eliminate such drawbacks, the present invention improves the suction effect of earth and sand without making the drag head itself, the drag arm, the joint between the drag arm and the hull, etc. heavy structures, thereby increasing the efficiency of drag suction dredging. This was done with the aim of increasing the number of people.

Embodiments of the present invention will be described below based on the drawings.

As shown in Figures 5 and 6, a drag head is attached to the tip of a drag arm that functions as a suction pipe provided on the side of the dredger, and an excavation blade drive shaft is provided inside the drag head. As shown in FIGS. 7 and 8, the excavator blade drive shaft 2, which is rotatably supported horizontally inside the drag head 1, is cut down by a motor (not shown) and excavated in the same direction as the traveling direction of the dredger. ), the excavating blade 3 is attached to the outer surface of the excavating blade drive shaft 2, and the drag head 1
The aft body 1a and the forebody 1b are connected by a rotation hinge 4, so that the aft body 1a can freely rotate around the rotation hinge 4, and the inside of the aft body 1a and the forebody 1b can be rotated by the rotation of the excavation blade 3. The aft body 1a is formed to have a wall thickness that is as close as possible to the outer circumference of the circle, and the bottom edge of the aft body 1a is inserted into the drag arm 7, which functions as a suction pipe, at the contact portion 6 with the seabed surface 5 as much as possible. In order to seal the seawater so as to prevent the formation of a seawater flow path, the aft body 1a is formed into a ski-like shape that is in continuous contact with the seabed surface 5. Furthermore, a seawater inlet 8 is provided at the bottom of the rear part of the aft body 1a. Seawater is prevented from being sucked in from locations other than the seawater inlet 8.

Now, with the start of the dredging work, the excavator blade drive shaft 2 rotates together with the excavator blade 3 in the clockwise direction in FIG. It is excavated continuously by 3. The excavated earth and sand is mixed with seawater sucked in from the seawater inlet 8 provided at the lower rear end of the aft body 1a, and is assisted by the rotation of the excavation blade 3 to form streamlines as shown in FIG. It is guided from inside the drag head 1 into the drag arm 7 and loaded into the mud hold on the dredger. At this time, since the digging blade 3 is rotating in the direction of cutting down and digging, the water flow at the bottom of the drag head 1 is directed to the cutting blade 3.
Since the drag head 1 is assisted from the front to the rear, seawater can be further prevented from flowing into the drag head 1 from the contact portion between the aft body 1a and the seabed surface 5.

Next, during the dredging of the seabed sediment, an obstacle 9 such as a rock is present in the seabed sediment, and this obstruction 9
To explain the case where the excavating blade 3 encounters the excavating blade 3 as shown in FIG.
When the excavation blade 3 collides with an obstacle 9, the excavation reaction force 10 that the excavation blade 3 receives from the obstacle 9 is a compressive force 11 on the drag arm 7 in the opposite direction to that in the round-up excavation method shown in FIG. Since the excavator blade 3 acts as a Even when an obstacle 9 is encountered, since the rotation is based on the cut-down excavation method, unlike the cut-up excavation method, the rotation does not actively bite into the obstacle 9, but instead uses the excavation torque of the excavation blade 3 as rotational torque as shown in FIG. As shown in the figure, the obstacle 9 can be overcome, thereby avoiding the obstacle 9 and preventing the digging blade 3 from being damaged.

It should be noted that the drag head of the present invention is not limited to the above-mentioned embodiments, and the shape of the digging blade 3,
Numbers, etc. may be changed arbitrarily other than those shown in the illustrations, etc.
Of course, various changes can be made without departing from the gist of the present invention.

As described above, according to the drag head with excavating blade of the present invention, the following excellent effects can be achieved.

(i) Since the excavation blade is rotated using the cut-down excavation method to excavate seabed soil, the excavation resistance force during dredging work can be reduced compared to the cut-up excavation method, and the excavation blade is free from obstacles. Even if an obstacle is encountered, forward force is applied by the dredger, so there is no need to make the drag head, the drag arm, and the joint between the drag arm and the dredger a heavy structure, and product costs can be reduced.

(ii) Since the drilling blade is rotated in a cutting-down drilling method, it is possible to prevent seawater from entering.

(iii) Since obstacles can be overcome, damage to the excavation blade and drag head itself can be prevented, and the operating efficiency of the dredger can be improved.

(iv) Since the distance between the rotational circumference of the excavation blade and the inner surface of the aft body and forebody of the drag head is narrowed, the mixture of excavated earth and sand and inhaled seawater can be effectively sucked into the dredger; Combined with active excavation work by the excavation blade, it is possible to improve the efficiency of drag suction dredging.

(v) Since the drag head is designed to prevent seawater from being inhaled from any ports other than the seawater inlet provided on the rear lower surface, the suction effect of soil and sand is improved, and the dredging efficiency can be improved.

[Brief explanation of the drawing]

Figure 1 is a side view of a conventional drag suction dredger, Figure 2 is a plan view from direction A in Figure 1, and Figure 3 is a side view of a conventional drag suction dredger.
4 is a cutaway side view of a conventional drag head, FIG. 4 is a plan view of FIG. 3, FIG. 5 is a cutaway side view of another example of the conventional drag head, and FIG. 6 is a cutaway plan view of FIG. 5. Fig. 7 is a cutaway side view of the drag head of the present invention, Fig. 8 is a view taken along the line B-B in Fig. 7, Fig. 9 is a side view showing the suction state of earth and sand and seawater, and Figs. 10 and 11. FIG. 3 is a side view showing a state when the excavating blade encounters an obstacle. 1...Drag head, 1a...Aft body,
1b...Fuor body, 2...Drilling blade drive shaft, 3
...Drilling blade, 6...Contact part, 7...Drag arm, 8...Seawater inlet, 9...Obstacle.

Claims (1)

[Scope of utility model registration request] An aft body and a forebody are connected to each other by a rotational hinge so that the aftbody can freely rotate around the rotational hinge, and an excavation blade drive shaft with an excavation blade attached to the outer surface is rotatably supported within the draghead main body. The drag head body is equipped with a motor that rotates the excavation blade drive shaft in the direction of cutting down and digging, and a seawater inlet is provided at the lower rear end of the aft body, and the part of the lower edge of the aft body other than the seawater inlet that contacts the seabed is shaped like a ski. A drag head with a digging blade.