JPH08127387A - Buoy - Google Patents

Abstract

PURPOSE: To decrease a drag so as to enable sinking a buoy and mooring force to decrease, by supporting under a float a flat ring with a sectional shape having an attack angle in the center direction, to increase restoring moment acting so as to negate tilt moment. CONSTITUTION: A flat ring 1, whose sectional shape has an attack angle in the center direction, is supported to the downward of a float 3. In the upstream part of the ring 1 thus supported, a negative attack angle is generated against a flow of water, and a drag Dr smaller than a perpendicular down facing lift L acts to generate restoring moment in a direction of negating tilting the float 3. In the downstream part of the ring 1, a positive attack angle is generated against a flow of water, and an up facing lift L and a drag Dr smaller than this lift L are generated to act as restoring moment of negating tilting the float 3. In this way, the float 3 can be small formed, and a mooring device can be also miniaturized. At the time of wavy motion, shake suppressing force can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a floating mooring type buoy, such as a traffic light buoy or a feeding buoy, which has improved posture stability in a water stream and in waves.

[0002]

2. Description of the Related Art As a structure for reducing the inclination of a buoy with respect to a current such as a tidal current, (a) the shape of a floating body is a disk. (Refer to Fig. 4) (b) A resistance element against water flow is provided. A cross-shaped resistance plate formed by combining vertical plates may be provided at the bottom of the floating body (see Fig. 5), or a short cylindrical resistance ring may be provided below the floating body. It is generally supported (see FIG. 6).

[0003]

In the case of (a), (1)
Since the lift moment L (downward) generated at the front edge of the lower surface of the floating body is used to obtain the restoring moment, the buoy sinks as the flow becomes faster. (2) The diameter of the floating body becomes large, and the volume efficiency of buoyancy is poor (many materials are required to obtain the same buoyancy). (3) There is a possibility of capsizing. (4) The vibration sensitivity is too sensitive and the riding comfort is poor. Although it is calm, it has the drawback of swaying irregularly.

[0004] In the case of (b), by utilizing the drag, for the method to generate a reverse moment of the tilting moment acting on the floating body in the drag D _r of the resistance plate or resistor rings, only resistor component increases drag The horizontal load on the buoy increases, and the buoy sinks and the mooring device becomes larger.

According to the present invention, in a water flow, a restoring moment acting to cancel a tilting moment due to a drag force acting on a floating body is large, a drag force is small, and a vibration damping force is large even in a wave, and stability is high. It is a buoy.

[0006]

In order to achieve this object, the present invention provides a buoy in which a flat ring whose cross-sectional shape has an attack angle (acute angle) in the central direction is supported below a floating body.

[0007]

In the water flow, the ring on the upstream side has a negative angle of attack with respect to the water flow, and the downward lift force L and the drag force D _r (D _r is smaller than L) act. Further, the ring on the downstream side has a positive angle of attack with respect to the water flow, an upward lift L and a drag force D _r work, and both act as opposite moments that cancel out the tilt moment M due to the drag force D _b of the buoy. Therefore, by appropriately adjusting the position and shape of the ring, both moments can be balanced and kept upright regardless of the slowness of the water flow.

Further, the drag force of the ring in the water flow is much smaller than the lift force, and therefore the drag force of the buoy as a whole does not increase much due to the ring. The floating body may be smaller than before. Furthermore, since the extension line of the center line of the ring cross section passes closer to the center of gravity (center of sway) of the buoy, it effectively works as a resistance plate against the sway caused by waves of the buoy and reduces the sway.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of a buoy embodying the present invention and is an explanation of the action of a ring in a water stream. Reference numeral 1 is a flat ring whose cross-sectional shape has an angle of attack toward the center. 2 is a pillar, 3 is a floating body, 4 is a mooring ring, and 5 is a mooring line. θ is the angle of attack, and the arrow is the direction of water flow.

The drag D _b due to the water flow acts on the buoy, and the tilt moment M acts to try to tilt it. Upstream portion of the ring 1 becomes a negative angle of attack to the water flow, the direction of the restoration moment counteracting together inclination of buoy work is lift L is smaller than this drag D _r of vertical downward. The downstream portion of the ring 1 acts as a restoration moment counteract both inclination of the buoy serves small drag D _r than the positive and attack angle becomes the upward lift L contrast flow. Therefore, if the ring is selected to have an appropriate size, an effective tidal current posture stabilizing effect with a small drag force and a large restoring force can be obtained.

FIG. 2 is an explanatory view of the action of the ring on the waves. When there are waves, the buoy sways about the center of gravity G. Since the extension of the center line of the ring cross section has an angle of attack θ, it passes near the center of gravity G, the projected area in the wobbling direction of the ring is large, and it is located farthest from the center of the wobbling. It acts as a resistance plate and produces a damping effect and an additional mass effect, and has a great effect of suppressing shaking.

Also, in shallow water where many buoys are installed, the water molecule motion trajectory of the wave becomes an ellipse that is long in the horizontal direction due to the influence of the seabed as shown by the arrow in FIG. 2, so the horizontal component of the wave force is the vertical component. Although larger, the ring 1 has a smaller horizontal projected area, and thus the wave force (wave forcing force) is smaller. Therefore, this ring is an efficient posture stabilizer that has a large sway suppression force (drag resistance) and a small sway compulsion force (oscillation force), and the buoy does not tilt even during tidal currents and has little sway during waves. It will be a buoy.

In the present embodiment, the ring (1) has a plate-shaped cross section, but it goes without saying that it may have a blade-shaped cross section as shown in FIG.

4 to 6 are explanatory views of a conventional buoy, FIG. 4 is a disk type buoy, FIG. 5 is a buoy having a cross resistance plate, and FIG. 6 is a buoy having a short cylindrical resistance ring. .

[0015]

[Effect] When the buoy of the present invention is used, the restoring moment that acts to cancel the tilting moment due to the drag force acting on the floating body due to the water flow is large, the drag force is small, and the sinking and mooring force of the buoy is small. Therefore, the floating body is small, the mooring device can be made small, and the sway suppression force is large in the waves, and the sway force (oscillating force) due to the waves is small. The light buoys for traffic signs and feeding buoys have the effect of providing a stable and economical buoy that has a long range of lighting and is comfortable to ride on, has good workability.

[Brief description of drawings]

FIG. 1 is an explanatory view of the action of a first embodiment of the present invention in a water stream.

FIG. 2 is an explanatory view of the operation of the first embodiment of the present invention in waves.

FIG. 3 is a sectional view of another embodiment of the ring.

FIG. 4 Disk-type buoy of a conventional example

FIG. 5 is a conventional buoy with a cross-shaped resistance plate.

FIG. 6 is a buoy having a conventional short cylindrical resistance ring.

[Explanation of symbols]

1 Ring 2 Strut 3 Floating body 4 Mooring ring 5 Mooring line θ Angle of attack D _b Drag force of buoy by water flow D _r Drag force of ring or cross resistance plate by water flow L Lifting force T Mooring force

Claims (1)

[Claims] 1. A buoy which is characterized in that a flat ring having a cross-sectional shape having an attack angle in the central direction is supported below a floating body.