JP2607009B2 - Turnbuoy for boat race and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boat race turn buoy, and more particularly to an improvement for improving the reliability thereof.

[0002]

2. Description of the Related Art Heretofore, a turn buoy for displaying a turning point at the time of a race, as shown in, for example, Japanese Utility Model Publication No. 58-48958, has been installed on the course of a boat racetrack. The specific structure of the conventional turn buoy will be described with reference to the drawings in FIG.
The turn buoy a is formed by integrally forming a hollow conical portion b located above a substantially central portion in the vertical direction and a hollow tire portion c located below the hollow conical portion b. The hollow conical portion b and the hollow tire portion c are formed by bonding a rubber sheet material in which a reinforcing cloth d (see FIGS. 12 to 14) is embedded. As a method of manufacturing the turn buoy a, a styrofoam forming die conforming to the shape of the turn buoy a is prepared, and the sheet material is bonded to the outer surface of the forming die. It was formed into a predetermined shape.

The structure of each part of the turn buoy a will be described. First, as shown in FIG. 12, stainless steel is provided near the connection between the hollow conical part b and the hollow tire part c inside the turn buoy a. A reinforcing plate e is provided. This reinforcing plate e includes a disk portion e1 and the disk portion e.
And a cylindrical portion e2 erected on an upper surface of the cylindrical portion e1. Is in contact with the inner peripheral surface of the lower end of the hollow conical portion b. A ring member e3 is integrally formed on the outer peripheral surface near the upper end of the cylindrical portion e2, and the ring member e3 is engaged with a concave portion b1 formed on the inner peripheral surface of the hollow conical portion b. The falling off of the reinforcing plate e is prevented. A wire f is wound around the connection between the hollow conical portion b and the hollow tire portion c. With such a configuration, the connecting portion between the hollow conical portion b and the hollow tire portion c is reinforced, and the peripheral portion of the connecting portion maintains a predetermined shape with a predetermined rigidity.

As shown in FIG. 13, the turn buoy a is provided at a plurality of positions on the bottom surface of the hollow tire portion c.
A nut member h is screwed into which an eye bolt g (see FIG. 11) for connecting a chain extending from an anchor for fixing the nut member to the water bottom surface is buried, and is protruded from the outer peripheral surface of the nut member h. Flange h1 is hollow tire c
The nut member h is positioned in a buried state inside the bottom surface of the nut member h.
It has a retaining structure.

Further, as shown in FIG. 14, an air valve i for injecting air into the turn buoy a is disposed at the center of the bottom surface of the hollow tire portion c. The air valve i has a nut member i1 having a screw hole penetrating in the thickness direction of the bottom surface of the hollow tire portion c embedded in the bottom surface, and a valve i2 screwed to the nut member i1. ing. Further, the nut member i1
A flange portion i3 similar to the above is protrudingly provided on the outer peripheral surface of the nut member i3. ing.

[0006]

However, in the turn buoy a having the above-described structure, there is a possibility that the following problems may occur, and improvement thereof has been desired. First, the nut members h eyebolt attachment which is embedded in the bottom surface of the middle empty tire portion c is disposed at a position where the lower end portion protrudes from the lower surface of the hollow tire section c (see FIG. 13), racing In the case where the boat comes into contact with the turn buoy a and the turn buoy a is overturned, there is a possibility that the boat or an athlete may come into contact with the protruding portion of the nut member h.

Further, a turn buoy a is provided from the air valve i.
When injecting air into the inside, air is injected from the opening of the nut member i1, and then the valve i2 is inserted into this opening.
Is screwed, but in this case, this valve i
Air leakage occurred during the screwing operation of No. 2, and sufficient air could not be injected into the inside of the turnbuy a, and it was difficult to set the buoyancy of the turnbuy a to a predetermined value. In addition, since the lower surface of the nut member i1 is disposed flush with the bottom surface of the hollow tire portion c, the valve h2 is screwed to the air valve i.
If the head of the boat 2 is in a protruding state and a screw or the like of the boat comes into contact with the valve i2 or the nut member i1, there is a possibility that the air valve i is damaged and air leakage occurs.

On the other hand, in the method of manufacturing the turn buoy a, as described above, the sheet material is bonded to the outer surface of the styrofoam forming die, so that the surface shape of the sheet material is regulated. However, unevenness is easily generated on the surface, and such an unevenness leads to deterioration of the appearance of the turn buoy a.

[0009]

Means taken by the present invention to solve each of the above problems are as follows.
The invention according to claim 1 is provided at a predetermined position on the water surface of a racetrack, and includes an upper hollow cone portion integrally formed of an elastic material and a lower hollow tire portion having a substantially flat bottom surface. It is premised on a boat race turn buoy consisting of: And, on the bottom surface of the hollow tire portion, a connecting member to which an anchor is connected is provided, and the lower end surface of the connecting member is flush with the bottom surface of the hollow tire portion, and the bottom surface of the hollow tire portion is The hollow tire portion is buried at an inner circumferential position having a predetermined dimension from the outer circumferential edge on the bottom surface so as not to protrude to the outer circumferential side from the outer circumferential edge.

According to a second aspect of the present invention, an air-filled interior is provided at a predetermined position on the water surface of a boat racetrack, and an upper hollow conical portion formed integrally with an elastic material and a substantially flat bottom surface are provided. And a lower buoy having a lower hollow tire portion. And, on the bottom surface of the hollow tire portion, a recessed portion is formed having a slope inclined toward the inside of the hollow tire portion at a predetermined acute angle with respect to the bottom surface, and the recessed portion is formed on the slope surface. An insect-rubber type valve member for allowing air to flow into the hollow tire portion and the hollow cone portion is provided.

According to a third aspect of the present invention, in the turn buoy for a boat race according to the first aspect, the recessed portion has a first inclined surface and a second inclined surface along a straight line passing through the center thereof. And each of the inclined surfaces is recessed so that an angle formed between the inclined surfaces is substantially a right angle. In addition, the first inclined surface is inclined at an angle of approximately 60 ° with respect to the bottom surface of the hollow tire portion, while the second inclined surface is inclined at an angle of approximately 30 ° with respect to the bottom surface of the hollow tire portion. An insect rubber type valve member is provided on the first inclined surface.

[0012] The invention described in claim 4 is the above-described claim 1 or 2.
In Motorboat for Tanbui of 2, wherein the connecting portion between the middle empty cone and the hollow tire section, made of an elastic material, a partition member that partitions the internal space of the inner space and the hollow tire portion of the hollow conical portion integrally Form. Further, in the partition member,
An opening is formed to allow the internal space of the hollow conical portion to communicate with the internal space of the hollow tire portion.

According to a fifth aspect of the present invention, there is provided the turn buoy for a boat race according to the fourth aspect, wherein an outer peripheral edge of the partition member is connected to a connecting portion between the hollow conical portion and the hollow tire portion, and the connecting portion is thick. The structure is formed as follows.

According to a sixth aspect of the present invention, there is provided a boat race including an upper hollow cone portion and a lower hollow tire portion which are installed at a predetermined position on the water surface of a boat racetrack and are integrally formed of an elastic material. It is premised on the method of manufacturing a turn buoy. An upper mold having an inner surface matching the outer surface shape of the hollow conical portion and a lower mold having an inner surface matching the outer surface shape of the hollow tire portion are detachably disposed, and An assembly part of the lower mold to the lower mold and an assembly part of the lower mold to the upper mold are opened. Then, before assembling each mold, a sheet-like elastic material is stuck along the entire inner surface of each mold, and then, simultaneously with assembling each mold, the upper mold is An edge of an elastic material located at an assembly portion with respect to the lower mold,
After integrally forming the elastic material into the predetermined shape of the turn buoy by integrally bonding the edge of the elastic material located at the part where the lower mold is attached to the upper mold, the molds are opened. did.

[0015]

According to the above construction, the following effects can be obtained in the present invention. According to the first aspect of the present invention, since the lower end surface of the connecting member is flush with the bottom surface of the hollow tire portion, even when the boat comes into contact with the turn buoy during a race and the turn buoy is capsized. Thus, a situation in which a boat or a competitor comes into contact with this connecting member is avoided. In addition, since this connecting member does not protrude to the outer peripheral side from the outer peripheral edge of the bottom surface of the hollow tire portion, the boat or the competitor does not come into contact even when installed on the water surface.

According to the second aspect of the present invention, since the air valve is provided with an insect-rubber type valve member, air leakage does not occur at the time of air injection, and a predetermined buoyancy is obtained in the turn buoy. The air injection amount can be adjusted. In addition, since this air valve is provided on an inclined surface that has an acute angle to the buoy bottom surface, when refilling air, only slightly raising a part of the turn buoy, this inclined surface becomes a surface that extends in the vertical direction In addition, the insertion direction of the air replenishing nozzle into the air valve can be set in the horizontal direction, so that workability is good.

According to the third aspect of the present invention, the recessed portion is provided with an inclined surface having an angle of approximately 60 ° and approximately 30 ° with respect to the bottom surface of the hollow tire portion. By disposing the member, the air valve is disposed at a position retracted from the bottom surface of the hollow tire portion, so that the screw or the like of the boat does not come into contact with the air valve, thereby preventing the breakage. Also, when lifting a part of the turn buoy slightly during the air refilling operation, the bottom of the buoy should be approximately 3
It is possible to make the insertion direction of the air replenishment nozzle horizontal by simply raising it slightly so that it becomes 0 °.

According to the fourth aspect of the present invention, since the conventional stainless steel reinforcing plate is eliminated, even when the boat comes into contact with the turn buoy during the race, the occurrence of cracks and the like is suppressed. In other words, the life is extended. Further, even if a crack occurs, the reinforcing plate is not exposed, so that damage to the boat and the like can be avoided. Further, since the partition member has an opening, it is necessary to provide only one inflow port for introducing air into the buoy.

According to the fifth aspect of the present invention, the outer peripheral edge of the partition member is connected to the connecting portion between the hollow conical portion and the hollow tire portion, and the connecting portion is formed to have a large thickness. The rigidity of the portion is sufficiently ensured, and even when an external force is applied, the peripheral portion of the connection portion maintains a predetermined shape.

In the sixth aspect of the present invention, the elastic material forming the hollow conical portion is formed along the inner surface of the upper mold, and the elastic material forming the hollow tire portion is formed along the inner surface of the lower mold. Will be. For this reason, the surface shape of the outer surface of the turn buoy is formed in a predetermined shape that conforms to the shape of the inner surface of each mold, and the surface of the turn buoy does not have irregularities.

[0021]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front view of a boat race turn buoy 1 according to the present embodiment, and FIG. 2 is a bottom view thereof. As shown in FIG. 1, the turn buoy 1 has a substantially conical hollow conical portion 2 located above a substantially central portion in the vertical direction, and a lower conical portion 2 which is located below the hollow conical portion 2. Tire parts 3a, 3b
(The manufacturing method will be described later). A reinforcing core 3c is buried between the two upper and lower tire portions 3a and 3b. The hollow conical portion 2 and the hollow tire portion 3 are formed by bonding a rubber sheet material in which a reinforcing cloth 4 (see FIGS. 4 and 5) is embedded. And
The turn buoy 1 is radially painted in two colors of red and white in a plan view so that a competitor can easily recognize it.

The turn buoy 1 has one eyebolt 5 and 6 attached to the upper end of the hollow conical portion 2 and four eyebolts 5 and 6 to the bottom surface of the hollow tire portion 3, respectively, as shown in FIG. Anchor 9 is connected to eyebolts 6, 6,... Attached to the bottom surface of hollow tire portion 3 via chain 7, detent 8, and the like. The turn buoy 1 is set at a predetermined position on the water surface.

Next, each part of the turn buoy 1 will be described, in particular, the configuration which is a feature of the present embodiment. As shown in FIG. 4, the connecting portion between the hollow conical portion 2 and the hollow tire portion 3 inside the turn buoy 1 extends from the connecting portion toward the inner side in the horizontal direction, and the inside of the hollow conical portion 2 is formed. Partition member 10 for partitioning the space from the internal space of hollow tire portion 3
Are arranged. The partition member 10 is made of a thin rubber material, and is formed integrally with the hollow conical portion 2 and the hollow tire portion 3. An opening (not shown) is formed in the partition member 10, and the opening connects the internal space of the hollow conical portion 2 to the internal space of the hollow tire portion 3. Accordingly, the outer peripheral edge of the partition member 10 is also connected to the connecting portion between the hollow conical portion 2 and the hollow tire portion 3, and this portion is locally thickened, The rigidity is sufficiently ensured, and the periphery of the connecting portion is configured to maintain a predetermined shape with a predetermined rigidity.

As shown in FIG. 5, a nut member 11 as a connecting member according to the present invention for screwing the eye bolt 6 is embedded in the bottom surface of the hollow tire portion 3. The nut member 11 is formed with a female screw 11a having a bottom opening at the lower end surface thereof.
The eye bolt 6 is screwed to 1a (see FIG. 1). To explain the state of embedding of the nut member 11, a disk-shaped flange portion 11b is protruded from an outer peripheral surface of the nut member 11 at a position slightly above the lower end portion. The nut member 11 is positioned above the reinforcing cloth 4 inside the bottom surface of the hollow tire portion 3 to form a nut retaining structure. As one of the features of the present embodiment, the nut member 11 is set at a position where the bottom surface thereof is flush with the bottom surface of the hollow tire portion 3. That is, in the nut member 11 of this example, the flange portion 11b is set at a slightly lower position as compared with the conventional one (shown in FIG. 13). The lower end portion of the nut member 11 does not protrude from the bottom surface of the hollow tire portion 3 in a state where the nut member 11 is embedded.

As shown in FIG. 2, an air valve 12 for injecting air into the turn buoy 1 is provided at the center of the bottom surface of the hollow tire portion 3. And FIG.
As shown in FIG.
The valve member 14 is disposed in the recessed portion 13a formed in the above. The valve fitting 13 shown in FIG.
As shown in FIG. 6 (b), the bottom surface has a substantially semi-elliptical shape when viewed from below, and the recessed portion 13a formed at the center thereof has the same substantially semi-elliptical shape when viewed from below. As shown, the one side surface 13b is formed by a first inclined surface according to the present invention, which is inclined at an angle of about 60 ° with respect to a horizontal plane. In the cross section shown in FIG. 6A, the other side surface 13c is formed by a second inclined surface of the present invention which is inclined at an angle of about 30 ° with respect to the horizontal plane. Therefore, the first inclined surface 13b and the second inclined surface 1
3c is 90 °.

The valve member 14 is an insect-rubber type valve attached to the first inclined surface 13b.
A rubber tube 14b or the like is attached to an opening of a nozzle 14a for communicating the internal space of the hollow tire portion 3 with the outside, and air injected from the nozzle 14a into the internal space of the hollow tire portion 3 is supplied to the rubber tube 14b. Does not leak to the outside by closing the opening of the nozzle 14a.

On the other hand, as shown in FIG. 7, a nut member 15 for screwing the eyebolt 5 provided at the upper end portion is embedded in the upper end portion of the hollow conical portion 2. The nut member 15 has the same configuration as the nut member 11 buried in the bottom surface of the hollow tire portion 3, and has a disk-shaped flange portion 15 a formed on the outer peripheral surface thereof.
Embedded in the upper end surface of the nut member 1 in this state.
5 is configured such that the upper end portion does not protrude from the upper end surface of the hollow conical portion 2. FIG. 8 shows eyebolts 5 and 6 screwed to the nut members 11 and 15, and bolt portions 5 a and 6 a of the eyebolts 5 and 6 are screwed into female threads of the nut members 11 and 15. By being worn, it can be assembled to the turn buoy 1. As described above, the turn buoy 1 of the present example is configured.

Next, the operation of manufacturing the turn buoy 1 will be described. The turn buoy 1 is manufactured using a molding die 16 as shown in FIG.
A rubber sheet as a material of the turn buoy 1 is bonded along the inner side surface of the mold 16 to form a predetermined shape. The mold 16 is a first mold 1 as an upper mold corresponding to the shape of the hollow conical portion 2.
6a, the left and right halves of the second mold dies 16b, 16b corresponding to the entire upper tire portion 3a and the lower half of the lower tire portion 3b of the hollow tire portion 3, and the lower portion of the hollow tire portion 3. And a third mold 16c corresponding to the shape of the lower half of the side tire portion 3b.
The lower mold of the present invention is constituted by the 16b and the third mold 16c.

Before assembling the upper mold and the lower mold, the lower mold has the second molds 16b, 16b and the third mold 16c mounted on the inner surface thereof. Paste the rubber sheet along. On the other hand, the first mold 1 as the upper mold
Also in 6a, a rubber sheet is stuck along the inner surface. Thus, each of the molds 16a, 16b, 16c
With the rubber sheet adhered to the inner surface of the first mold 16 and the upper mold and the lower mold, the rubber positioned at the joint portion of the first mold 16a with the second mold 16b is simultaneously mounted. After integrally bonding the edge of the sheet and the edge of the rubber sheet located at the part where the second mold 16b is assembled to the first mold 16a, and forming the rubber sheet into the predetermined shape of the turn buoy 1 By opening the molds 16a, 16b and 16c, the turn buoy 1 having a predetermined shape as described above is manufactured.

As described above, the turn buoy 1 is attached to the inner surface of the molding die 16 by sticking the rubber sheet along the inner surface.
Therefore, the surface shape of the outer surface of the turn buoy 1 is formed along the shape of the inner surface of each of the molds 16a, 16b, 16c. It can be manufactured without causing irregularities or the like on the surface.

Hereinafter, the turn buoy 1 constructed as described above will be described.
The function at the time of using will be described. First, as an operation of installing the turn buoy 1 on a course, air is injected from the nozzle 14a of the air valve 12 disposed on the bottom surface of the hollow tire portion 3 toward the hollow tire portion 3. At this time, since the air valve 12 is an insect-rubber type valve, air leakage does not occur, and the air injection amount for obtaining a predetermined buoyancy in the turn buoy 1 can be adjusted. Then, the turn buoy 1 into which the air has been injected in this manner is engaged with the bottom surface of the hollow tire portion 3 by locking the anchor 9 connected to the bottom surface of the hollow tire portion 3 via the eyebolt 6, the chain 7, and the detent 8 to the bottom surface below the water surface. Installed at a predetermined position on the course.

Then, in this way, the race is started with the turn buoy 1 installed at a predetermined position,
In the case where the boat comes into contact with the turn buoy 1 during a race, the turn buoy 1 of this example does not have a stainless steel reinforcing plate as in the prior art, so that cracks are suppressed and air leakage is prevented. And a longer life can be achieved. Further, even if a crack is generated, the reinforcing plate is not exposed as in the related art, so that damage to the boat and the like can be avoided, and the safety is high.

The nut member 11 for mounting an eyebolt buried in the bottom surface of the hollow tire portion 3 does not protrude from the lower surface of the hollow tire portion 3 at its lower end portion.
This configuration also allows the boat to turn
When the turn buoy 1 is overturned by contact with
A situation in which a boat or an athlete comes into contact with the nut member 11 can be avoided, and safety is well ensured.

Further, since the air valve 12 is disposed at a position retracted from the bottom surface of the hollow tire portion 3, there is no possibility that a screw or the like of a boat comes into contact with the air valve 12, thereby preventing breakage thereof. it can.

As described above, in the turn buoy 1 of the present embodiment, safety and practicality are improved by improving each part which has been conventionally regarded as a problem.

In this embodiment, the rubber sheet in which the reinforcing cloth 4 is embedded is used as the material of the turn buoy 1. However, the present invention is not limited to this, and a resin material such as fiber reinforced plastic is used. You may make it.

[0037]

As described above, according to the present invention, the following effects can be obtained. According to the invention as set forth in claim 1, a connecting member to which an anchor is connected is provided on the bottom surface of the hollow tire portion, and the lower end surface of the connecting member is flush with the bottom surface of the hollow tire portion, and is hollow. In order not to protrude to the outer peripheral side from the outer peripheral edge of the bottom of the tire part,
Since it is buried at an inner peripheral position having a predetermined dimension from the outer peripheral edge on the bottom surface, a situation in which a boat or a competitor comes into contact with the connecting member during a race can be avoided, and high safety can be secured.

According to the second aspect of the present invention, since the insect rubber type valve member is provided in the recessed portion recessed with respect to the bottom surface of the hollow tire portion, air leaks when air is injected from the air valve. Therefore, it is possible to easily adjust the amount of air to be supplied to the turn buoy to obtain a predetermined buoyancy. In addition, since the air valve is provided on an inclined surface with an acute angle to the buoy bottom surface, at the time of air refilling work, by slightly lifting a part of the turn buoy, this inclined surface becomes a surface extending in the vertical direction, The insertion direction of the air replenishing nozzle into the air valve can be horizontal, and good workability can be obtained.

According to the third aspect of the present invention, the recessed portion has an angle of approximately 60 ° and approximately 30 ° with respect to the bottom surface of the hollow tire portion.
The air valve is disposed at a position retracted from the bottom surface of the hollow tire portion by providing an inclined surface having an angle of and the insect rubber type valve member is disposed on the former inclined surface, such as a screw of a boat. Are prevented from coming into contact with each other, and the damage is prevented. In addition, when slightly lifting a part of the turn buoy during the air replenishing operation, it is possible to make the insertion direction of the air replenishing nozzle horizontal by only slightly lifting the buoy bottom so as to be approximately 30 ° with respect to the water surface. In addition, good workability of the air replenishment work can be obtained.

According to the fourth aspect of the present invention, a partition member for partitioning the internal space of the hollow conical portion and the internal space of the hollow tire portion is provided at a connecting portion between the hollow conical portion and the hollow tire portion, Since this partition member was formed integrally with the hollow conical portion and the hollow tire portion by an elastic material, the boat contacted the turn buoy during the race due to the elimination of the conventional stainless steel reinforcing plate. Even in such a case, generation of cracks and the like can be suppressed, air leakage can be prevented, and the life can be extended. Further, since there is no problem that the boat is damaged by the exposed portion of the reinforcing plate as in the related art, safety can be improved. Further, by forming an opening for communicating the internal space of the hollow conical portion and the internal space of the hollow tire portion in the partition member, the inflow port for inflow of air into the buoy may be provided at only one place,
The air inflow operation can be simplified.

According to the fifth aspect of the present invention, the outer peripheral edge of the partition member is connected to the connecting portion between the hollow conical portion and the hollow tire portion, and the connecting portion is formed to be thick. the rigidity of the connection portion is sufficiently secured, even if an external force acts, the connecting portion periphery becomes possible to maintain a predetermined shape, whereby, while ensuring the effect of the claim 4, wherein Tanbui Can be prevented from becoming out of shape.

According to the sixth aspect of the present invention, the elastic material forming the hollow conical portion is formed along the inner surface of the upper mold, and the elastic material forming the hollow tire portion is formed along the inner surface of the lower mold. As a result, the surface shape of the outer surface of the turn buoy will be formed in a predetermined shape that conforms to the shape of the inner surface of each mold, and the surface of the turn buoy will not have irregularities etc. Thus, it is possible to obtain a manufacturing method capable of ensuring the appearance of the turn buoy.

[Brief description of the drawings]

FIG. 1 is a front view in which a part of a turn buoy is cut away.

FIG. 2 is a bottom view of the turn buoy.

FIG. 3 is a diagram showing an installation state of a turn buoy.

FIG. 4 is a longitudinal sectional view of a connecting portion between a hollow conical portion and a hollow tire portion.

FIG. 5 is a longitudinal sectional view of an eyebolt mounting portion on the bottom surface of the hollow tire portion.

FIG. 6 is a view showing an air valve.

FIG. 7 is a longitudinal sectional view of an eyebolt mounting portion on the upper end surface of the hollow conical portion.

FIG. 8 is a view showing an eyebolt.

FIG. 9 is a longitudinal sectional view of a turn buoy molding die.

FIG. 10 is a view showing a turn buoy molding die.

FIG. 11 is a diagram showing a conventional turn buoy.

FIG. 12 is a diagram corresponding to FIG. 4 in a conventional turn buoy.

FIG. 13 is a diagram corresponding to FIG. 5 in a conventional turn buoy.

FIG. 14 is a longitudinal sectional view showing a peripheral portion of an air valve of a conventional turn buoy.

[Description of Signs] 1 Turn Buoy 2 Hollow Conical Part 3 Hollow Tire Part 9 Anchor 10 Partition Member 11 Nut Member (Connecting Member) 12 Air Valve 13a Depressed Part 13b One Side (Slope) 14 Valve Member 16 Mold

Claims (6)

(57) [Claims] 1. A boat race provided at a predetermined position on the water surface of a boat racetrack and comprising an upper hollow conical portion integrally formed of an elastic material and a lower hollow tire portion having a substantially flat bottom surface. In the turn buoy, a connecting member to which an anchor is connected is provided on the bottom surface of the hollow tire portion, and the lower end surface of the connecting member is flush with the bottom surface of the hollow tire portion, and A turn buoy for a boat race, wherein the turn buoy is buried at an inner peripheral position having a predetermined dimension from the outer peripheral edge of the bottom surface of the hollow tire portion so as not to protrude outward from the outer peripheral edge of the bottom surface of the hollow tire portion. 2. A lower hollow tire having an upper hollow conical portion formed substantially of an elastic material and a substantially flat bottom surface, wherein the lower hollow tire is installed at a predetermined position on the water surface of a racetrack with air enclosed therein. A concave portion recessed on the bottom surface of the hollow tire portion having a slope inclined toward the inside of the hollow tire portion at a predetermined acute angle with respect to the bottom surface. A turn buoy for a boat race, characterized in that a portion is formed, and an insect rubber type valve member for flowing air into the hollow tire portion and the hollow cone portion is provided on the inclined surface. 3. The recessed portion has a first inclined surface and a second inclined surface in a vertical cross section along a straight line passing through the center thereof, and an angle formed by each of the inclined surfaces is substantially a right angle. The first inclined surface is inclined at an angle of approximately 60 ° with respect to the bottom surface of the hollow tire portion, while the second inclined surface is approximately inclined with respect to the bottom surface of the hollow tire portion. 3. The turn buoy for a boat race according to claim 2 , wherein the buoy is inclined at an angle of 30 [deg.], And an insect rubber type valve member is provided on the first inclined surface. The coupling portion between 4. A middle empty cone and the hollow tire section, made of an elastic material, a partition member for partitioning the internal space and the internal space of the hollow tire portion of the hollow conical portion is formed integrally The turn buoy for a boat race according to claim 1 or 2 , wherein the partition member is formed with an opening communicating the internal space of the hollow conical portion and the internal space of the hollow tire portion. 5. The partition member has an outer peripheral edge connected to a connecting portion between the hollow conical portion and the hollow tire portion, and the connecting portion is formed thick.
4. A turn buoy for a boat race according to 4 . 6. A method for manufacturing a turn-buoy for a boat race, comprising: an upper hollow cone portion and a lower hollow tire portion which are installed at a predetermined position on the water surface of a racetrack and are integrally formed of an elastic material. An upper mold having an inner surface matching the outer surface shape of the hollow conical portion and a lower mold having an inner surface matching the outer surface shape of the hollow tire portion are detachably arranged, The assembly part of the upper mold with respect to the lower mold and the assembly part of the lower mold with respect to the upper mold are left open, respectively. Before assembling each mold, the entire inner surface of each mold is A sheet-like elastic material is pasted along the edge of the elastic material, and thereafter, at the same time as each of the molds is assembled, the edge of the elastic material located at the assembly portion with respect to the lower mold of the upper mold, Edge of resilient material located at the part of the mold to be assembled to the upper mold A method for manufacturing a turn-buoy for a boat race, wherein the elastic material is formed into a predetermined shape of the turn buoy, and each mold is opened.