Patent Application
20250115335
The present invention relates to a fin to be attached to a board, for example, a surfboard.
A fin that plays a role of a rudder is attached to a back surface of a surfboard, etc., to stabilize a straight-running property and a steering property of the surfboard. In such a fin, a shape of the entire fin, flexibility of the fin, etc. influence the straight-running property and the steering property of the surfboard. In particular, it is known that the flexibility of the fin largely depends on hardness of a material that configures the fin, a hard and less flexible fin less easily holds water so that the straight-running property is enhanced, and a soft and flexible fin more easily holds water so that the steering property is enhanced.
A fin of Patent Literature 1 is made by, between a pair of molds corresponding to a shape of the fin, laminating thick core mats, etc. having the substantially same shape as the shape of the fin, applying polyester resin, further laminating glass cloth, etc. woven with glass fiber on the outer side thereof, applying polyester resin, and hardening while pressurizing. In the fin like Patent Literature 1, by laminating the thick core mats, etc. inside the fin, it is possible not only to simplify a manufacturing process in comparison to a conventional fin manufactured by laminating 20 to 30 layers of glass cloth, but also to realize weight reduction of the fin while having the substantially same thickness as the conventional fin.
Patent Literature 1: Japanese Patent Application Publication No. S62-246383 (page 2 to page 3, FIG. 1)
However, in the fin like Patent Literature 1, the core mats, etc. having the substantially same shape as the shape of the fin extend to a leading end part of the fin called as a tip, and these are hardened by polyester resin in a state of being covered from the outer side by the glass cloth. Therefore, there is a problem that while the fin is excellent in the straight-running property, the entire fin is hard and less flexible and less easily holds water, so that a steering property is poor.
The present invention is achieved focusing on such a problem, and an object thereof is to provide a fin excellent in a steering property in addition to a straight-running property of a board.
In order to solve the problem described above, a fin according to the present invention is a fin to be attached to the back surface side of a board, wherein a core member having high strength is provided in the fin so as to be arranged biasedly toward a board side of the fin. According to the aforementioned feature of the present invention, upon receiving fluid resistance at the time of changing the sailing direction of the board, the board side of the fin becomes less flexible and a leading end part of the fin becomes flexible. Thus, it is possible to provide a fin excellent in a steering property in addition to a straight-running property of the board.
It may be preferable that the core member is arranged along an outer shape of the fin. According to this preferable configuration, it is possible to make strength distribution which does not inhibit original functions of the fin.
It may be preferable that the core member extends to a leg portion of the fin to be attached to the back surface side of the board. According to this preferable configuration, it is possible to reinforce the leg portion by the core member.
It may be preferable that a leading end of the core member is positioned on the board side of a top point of a rear edge portion of the fin. According to this preferable configuration, a portion of the fin close to the leading end side becomes flexible, and thus the steering property of the board is improved.
It may be preferable that a rear end of the core member is positioned on the front side of a base point of a rear edge portion of the fin. According to this preferable configuration, a portion of the fin close to the rear end side becomes flexible, and thus the steering property of the board is improved.
It may be preferable that the core member is formed of a wire rod. According to this preferable configuration, it is possible to reduce weight of the fin.
It may be preferable that the core member is bonded to a base member forming the fin. According to this preferable configuration, it is possible to enhance strength of the base material and strength of the core member configuring the fin with respect to each other.
Modes for carrying out a fin according to the present invention will be described below based on embodiments.
A fin according to a first embodiment of the present invention will be described with reference to
The fin according to the first embodiment of the present invention is to be attached to the back surface side of the board. It is noted that although a fin to be attached to a surfboard 2 serving as the board will be described in the present embodiment, the fin may be attached to other boards such as a bodyboard or a wakeboard.
As shown in
The center 1C is arranged substantially fin orthogonally to the back surface 2a in center of the right and left direction of the surfboard 2. The side fins 1L, 1R are arranged so as to be displaced on the front side with respect to the center fin 1C. In detail, the side fins 1L, 1R are inclined in the directions of separating from each other in the right and left direction toward a lower end, and also inclined in the directions of separating from each other in the right and left direction from a front end toward a rear end. It is noted that in the surfboard 2 of the present embodiment, the mode in which the three fins 1L, 1C, 1R are provided is described. However, the present invention is not limited to this but the number of the fins, arrangement, etc. may be freely changed.
Next, a structure of the center fin 1C will be described. It is noted that the side fins 1L, 1R have the substantially same configuration as the center fin 1C except for a configuration formed in a so-called flat foil in which a surface toward the inner side in the right and left direction is formed in a flat surface, and a surface toward the outer side in the right and left direction is formed in a convex curved surface (see
As shown in
In the present embodiment, the base member 10 is mainly made of polycarbonate and has elasticity by adding an appropriate amount of glass powder. Also, the base member 10 is semi-transparent and lightweight by being mainly made of polycarbonate. The base member 10 of the present embodiment has an outer shape gradually extending rearward from the upper portion base end side thereof toward the lower portion leading end side as a whole. In particular, a rear edge portion 10a forming an outer edge of the rear side of the base member 10 has an outer shape extending rearward while gradually curving from a base point P1 of an upper end thereof toward a top point P2 of a leading end (point of a rearmost end).
It is noted that the base member may be mainly made of, for example, other synthetic resin such as polyester resin or silicon resin, rubber, etc. other than polycarbonate as long as it has elasticity that the fin is required, or a filler or various additive agents, etc. may be added.
Also, in the present embodiment, in the base member 10, two front and rear leg portions 12, 12 protruding upward from a base 10b that configures an upper end portion of the fin and extends substantially horizontally are integrally formed. It is noted that the fin in the present embodiment is attached to the back surface 2a of the surfboard 2 by inserting the leg portions 12, 12 into a fin box 3 provided on the back surface 2a of the surfboard 2 and fixing with a bolt 4 (see
In the first embodiment, the core member 11 is a single wire rod configured by stainless steel, the wire rod having a cross-section of a circular shape (see
It is noted that the core member may be configured by, for example, other metal such as aluminum or titanium, synthetic resin, wood, bamboo, etc. other than stainless steel as long as it has strength higher than the base member. Also, the core member may be configured by the same material as the base member, and for example, by adding a filler of glass fiber, carbon fiber, etc. to the same material as the base member, the strength may be enhanced more than the base member.
Also, the wire rod used as the core member is not limited to the one having the cross-section of the circular shape, but for example, the shape of the cross-section may be other shapes such as an ellipse shape, a polygonal shape, a T shape, or an H shape, and alternatively, a shape of a cross-section of a wire rod used as the core member may be a flat plate shape short in the thickness direction of the fin. Also, in the wire rod used as the core member, the shape of the cross-section, a cross-sectional area, etc. may be partially changed in accordance with a required pliancy characteristic of the fin. For example, as the core member, by adopting a plate spring member having a shape of a cross-section that is a flat plate shape short in the thickness direction of the fin as described above, it is possible to improve an elastically restoring force of the fin and also dramatically enhance the pliancy characteristic of the fin. Also, the wire rod used as the core member may have a hollow structure.
Also, the core member 11 is arranged along the outer shape of the fin inside the base member 10. In detail, the core member 11 is bent along the outer shape of the fin, and a rear end 11a thereof is positioned on the front side of the base point P1 of the rear edge portion 10a of the fin. That is, the core member 11 is bent so as to be positioned on the front side of an imaginary line a passing through the base point P1 and extending orthogonally to the base 10b of the fin. It is noted that the rear end 11a of the core member 11 is a portion positioned on a rearmost end among the entire core member 11.
Also, a leading end 11b (lower end) of the core member 11 is positioned on the upper side of the top point P2 of the rear edge portion 10a of the fin. That is, the core member 11 is bent so that the leading end 11b thereof is positioned on the upper side of an imaginary line β passing through the top point P2 and extending in parallel to the base 10b of the fin. It is noted that the leading end 11b of the core member 11 is a portion positioned on a most leading end (lowermost end) among the entire core member 11.
Also, in the core member 11, both upper end portions 11c, 11d extend to insides of the two front and rear leg portions 12, 12. In particular, an end surface of the upper end portion 11c on the front side is exposed on an upper surface 12a of the leg portion 12. It is noted that the exposed part of the core member 11 may be covered by using the material of the base member 10, a caulking material, etc.
Also, as shown in
Now, a manufacturing method of the center fin 1C will be described. In the first embodiment, the center fin 1C is manufactured by so-called insert molding in which, in a state where the core member 11 is arranged and fixed in advance in substantial center of the thickness direction (right and left direction) of a mold corresponding to the shape of the fin, the heated and melted material of the base member 10 is cast into the mold, cooled down, and solidified. Thereby, the base member 10 is welded to the core member 11.
As described above, in the fin, the core member 11 having the high strength is arranged biasedly toward the surfboard 2 side (upper side). According to this, as shown in
Also, strength on the surfboard 2 side (upper side) of the fin is easily ensured by the core member 11. Thus, it is possible to suppress the thickness of the fin.
Also, the core member 11 is arranged along the outer shape of the fin. Thus, it is possible to make strength distribution which does not inhibit original functions of the fin.
Also, the core member 11 extends to the insides of the leg portions 12, 12 of the fin attached to the back surface 2a of the surfboard 2. Thus, it is possible to reinforce the leg portions 12, 12 by the core member 11.
Also, the rear end 11a of the core member 11 is positioned on the front side of the base point P1 of the rear edge portion 10a of the fin. Thus, a portion of the fin close to the rear end side becomes flexible, and thus the steering property of the surfboard 2 is improved. Also, the leading end 11b of the core member 11 is positioned on the upper side of the top point P2 of the rear edge portion 10a of the fin. Thus, a portion of the fin close to the leading end side becomes flexible, and thus the steering property of the surfboard 2 is improved.
Also, the core member 11 is the wire rod. Thus, it is possible to reduce weight of the fin while exerting the high strength.
Also, the core member 11 is bonded to the base member 10 by welding the base member 10 to the outer surface thereof. Thus, it is possible to enhance strength of the base member 10 and the strength of the core member 11 configuring the fin with respect to each other. Also, the core member 11 less easily directly touches water. Thus, it is possible to prevent corrosion of the core member 11. Also, a clearance is not formed between the core member 11 and the base member 10. Thus, it is possible to suppress invasion of water into the fin or an increase in the weight of the fin due to water absorption of the base member 10 and the core member 11.
Also, the base member 10 is semi-transparent by being mainly made of polycarbonate. Thus, it is possible to confirm the core member 11 arranged inside the base member 10 from the outside, and early find abnormality such as a position gap or breakage. Also, by making the core member 11 arranged inside the base member 10 visible from the outside, it is possible to enhance a design property. In this way, the base member preferably has translucency.
Also, the fin of the first embodiment is manufactured by insert molding. Thus, it is possible to simplify a manufacturing process.
It is noted that in the fin in the first embodiment, by changing a bending shape of the wire rod configuring the core member, the pliancy characteristic of the fin is adjustable, as a matter of course. It is noted that in order to exert the pliancy characteristic of the fin with which both the straight-running property and the steering property of the surfboard 2 described above can be obtained, the wire rod is preferably bent so that the rear end of the core member is positioned on the front side of the base point P1 of the rear edge portion 10a of the fin, and the leading end (lower end) of the core member is positioned on the upper side of the top point P2 of the rear edge portion 10a of the fin. In other words, in the fin, by not arranging the core member on the rear side of the imaginary line a and on the lower side of the imaginary line β, it is possible to enhance the elasticity by the core member on the base end side of the fin and also ensure original pliability of the base member 10 on the leading end side of the fin. That is, the pliancy characteristic of the fin with which both the straight-running property and the steering property of the surfboard 2 can be obtained is more easily exerted.
Also, the base member is not limited to the one configured by a single layer but may be configured by, for example, laminating a plurality of layers which have different materials from each other.
Also, in the core member, both the upper end portions are not always required to extend to the insides of the leg portions 12, 12. In this case, from a viewpoint of exerting the strength of the fin and the pliancy characteristic of the fin with which both the straight-running property and the steering property can be obtained, the upper end portions of the core member preferably extend to the vicinity of the base 10b.
Also, the core member may be configured by a plurality of wire rods divided in the extending direction thereof, or may be configured by a plurality of wire rods provided in parallel in the width direction.
Next, a fin according to a second embodiment will be described with reference to
As shown in
In the second embodiment, the core members 211A, 211B are two wire rods configured by stainless steel, each of the wire rods having a cross-section of a circular shape (see
It is noted that the core members 211A, 211B may be configured by wire rods having not only different lengths but also different widths or materials, etc. For example, as the core members, by adopting plate spring members each having a shape of a cross-section that is a flat plate shape short in the thickness direction of the fin as described above, it is possible to improve an elastically restoring force of the fin and also dramatically enhance a pliancy characteristic of the fin.
Also, the core members 211A, 211B are arranged along the outer shape of the fin inside the base member 10. In detail, the core member 211A is curved along a shape of the fin on the front side, and the core member 211B is curved along a shape of the fin on the rear side.
Also, among the core members 211A, 211B, a rear end 211Ba of the core member 211B extending to the rear side is positioned on the front side of a base point P1 of a rear edge portion 10a of the fin. That is, the core members 211A, 211B extend to positions on the front side of an imaginary line a passing through the base point P1 and extending orthogonally to a base 10b of the fin. It is noted that the rear end 211Ba of the core member 211B is a portion positioned on a rearmost end among the entire core member 211B.
Also, among the core members 211A, 211B, a leading end 211Ab (lower end) of the core member 211A extending to the leading end side (lower side) is positioned on the upper side of a top point P2 of the rear edge portion 10a of the fin. That is, the core members 211A, 211B extend to positions on the upper side of an imaginary line β passing through the top point P2 and extending in parallel to the base 10b of the fin. It is noted that the leading end 211Ab of the core member 211A is a portion positioned on a most leading end (lowermost end) among the entire core member 211A.
Also, the core members 211A, 211B extend so as to gradually come close toward the lower side. It is noted that the core members 211A, 211B are not limited to the ones respectively formed to have the same diameter over the entire length, but for example, the leading end 211Ab of the core member 211A or the rear end 211Ba of the core member 211B may be formed to have a large diameter, or may be formed in a tapering shape.
Also, in the core members 211A, 211B, end portions 211Ac, 211Bc on the upper side respectively extend to insides of two front and rear leg portions 12, 12. End surfaces of the end portions 211Ac, 211Bc of the core members 211A, 211B are exposed on an upper surface 12a of the leg portion 12. It is noted that the exposed parts of the core members 211A, 211B may be covered by using a material of the base member 10, a caulking material, etc.
Also, as shown in
Now, a manufacturing method of the side fin 1L will be described. In the second embodiment, the side fin 1L is manufactured by firstly casting the heated and melted material of the base member 10 into a mold corresponding to a shape of the fin, cooling down and solidifying, and then respectively inserting the core members 211A, 211B from the upper surfaces 12a of the leg portions 12, 12 of the base member 10. In detail, the mold is configured so that insertion holes 10c for inserting the core members 211A, 211B are respectively formed on the upper surfaces 12a of the leg portions 12, 12 in advance at the time of solidifying the base member 10 in the mold, and the core members 211A, 211B are inserted in a state where an appropriate amount of the adhesive 210 is charged into the insertion holes 10c. Thereby, in the insertion holes 10c, the outer surfaces of the core members 211A, 211B are bonded to the base member 10 over the entire length by the adhesive 210.
It is noted that the fin of the second embodiment may be manufactured by insert molding as well as the fin of the first embodiment. In this case, the base member 10 is welded to the outer surfaces of the core members 211A, 211B.
According to this, by dividing the core members 211A, 211B into the two wire rods, in comparison to a wire rod having a bent shape as in the first embodiment, strength of the core members 211A, 211B on the leading end side is more easily lowered. Thus, it is possible to make a leading end part of the fin flexible.
Also, among the core members 211A, 211B, the rear end 211Ba of the core member 211B extending to the rear side is positioned on the front side of the base point P1 of the rear edge portion 10a of the fin. Thus, a portion of the fin close to the rear end side becomes flexible, and thus the steering property of the surfboard 2 is improved. Also, among the core members 211A, 211B, the leading end 211Ab (lower end) of the core member 211A extending to the leading end side (lower side) is positioned on the upper side of the top point P2 of the rear edge portion 10a of the fin. Thus, a portion of the fin close to the leading end side becomes flexible, and thus the steering property of the surfboard 2 is improved.
Also, the outer surfaces of the core members 211A, 211B are bonded to the base member 10 by the adhesive 210. Thus, it is possible to enhance strength of the base member 10 and the strength of the core members 211A, 211B configuring the fin with respect to each other. Also, the core members 211A, 211B less easily directly touch water. Thus, it is possible to prevent corrosion of the core members 211A, 211B. Also, a clearance is not formed between the core members 211A, 211B and the insertion holes 10c in the base member 10. Thus, it is possible to suppress invasion of water into the fin or an increase in weight of the fin due to water absorption of the base member 10 and the core members 211A, 211B.
Also, the fin of the second embodiment is manufactured by inserting the core members 211A, 211B later into the base member 10 formed by the mold. Thus, it is possible to simplify a manufacturing process.
It is noted that the insertion holes 10c are not limited to the ones formed by the mold but may be formed by piercing the formed base member 10 by using a drill, etc.
Also, a clearance between the core members 211A, 211B and the insertion holes 10c is not required to be charged with the adhesive. In this case, however, the clearance is preferably so small that the core members 211A, 211B do not move relatively to the base member 10.
Also, in the fin in the second embodiment, by changing not only length, width, material, etc. of the wire rods configuring the core members 211A, 211B but also curvature or arrangement of the core members 211A, 211B, the pliancy characteristic of the fin is adjustable, as a matter of course.
Also, the core member may be configured by one wire rod or three or more wire rods.
Next, a fin according to a third embodiment will be described with reference to
As shown in
In the third embodiment, the core member 311 is a plate member configured by stainless steel. It is noted that the core member 311 is a flat plate member whose entire thickness is substantially uniform.
It is noted that the core member may be configured by, for example, other metal such as aluminum or titanium, synthetic resin, wood, bamboo, etc. other than stainless steel as long as it has strength higher than the base member. Also, the core member may be configured by the same material as the base member, and for example, by adding a filler of glass fiber, carbon fiber, etc. to the same material as the base member, strength may be enhanced more than the base member.
Also, the plate member used as the core member is not limited to the one whose entire thickness is substantially uniform but for example, the plate member may be made thin and flexible by pressing the leading end side (lower end side). Also, the leading end side of the plate member used as the core member may be made flexible by providing a groove, a through hole, etc.
Also, the core member 311 is arranged along the outer shape of the fin inside the base member 10. In detail, the core member 311 has an outer shape close to the outer shape of the fin, and a rear end 311a thereof is positioned on the rear side of a base point P1 of a rear edge portion 10a of the fin. That is, the core member 311 extends to a position on the rear side of an imaginary line a passing through the base point P1 and extending orthogonally to a base 10b of the fin. By doing so, it is possible to exert high rigidity by the core member 311 over to the rear end side of the fin. It is noted that the rear end 311a of the core member 311 is a portion positioned on a rearmost end among the entire core member 311.
Also, a leading end 311b (lower end) of the core member 311 is positioned on the upper side of a top point P2 of the rear edge portion 10a of the fin. That is, the core member 311 extends to a position on the upper side of an imaginary line β passing through the top point P2 and extending in parallel to the base 10b of the fin. It is noted that the leading end 311b of the core member 311 is a portion positioned on a most leading end (lowermost end) among the entire core member 311.
According to this, by configuring the core member 311 by the plate member, it is possible to ensure strength even when the core member 311 is thin, and it is possible to reduce thickness of the entire fin.
Also, the outer shape of the core member 311 can be made close to the outer shape of the fin. Thus, it is possible to make strength distribution which does not inhibit original functions of the fin.
It is noted that the fin of the third embodiment can be manufactured by any method among a manufacturing method by insert molding as in the first embodiment, and a manufacturing method of forming the base member 10 and then inserting the core member as in the second embodiment.
Also, the core member 311 may have convex portions extending to insides of leg portions 12, 12.
Also, the core member 311 may be divided into a plurality of members, and for example, the plate member configuring the core member may be divided into the front side and the rear side.
Next, a fin according to a fourth embodiment will be described with reference to
As shown in
In the fourth embodiment, the core member 411A is a single wire rod configured by stainless steel, and the core member 411B is a plate member configured by stainless steel. Also, the core member 411A is bent along part of an outer periphery of the core member 411B and arranged so as to contact with the core member 411B. It is noted that the core members 411A, 411B may be separate bodies or may be integrated.
Also, a rear end 411Aa of the core member 411A is positioned on the front side of a base point P1 of a rear edge portion 10a of the fin. That is, the core member 411A is bent so as to be positioned on the front side of an imaginary line a passing through the base point P1 and extending orthogonally to a base 10b of the fin. It is noted that the rear end 411Aa of the core member 411A is a portion positioned on a rearmost end among the entire core member 411A.
Also, a leading end 411Ab (lower end) of the core member 411A is positioned on the upper side of a top point P2 of the rear edge portion 10a of the fin. That is, the core members 411A, 411B are bent so as to be positioned on the upper side of an imaginary line β passing through the top point P2 and extending in parallel to the base 10b of the fin. It is noted that the leading end 411Ab of the core member 411A is a portion positioned on a most leading end (lowermost end) among the entire core member 411A.
Also, in the core member 411A, both upper end portions 411Ac, 411Ad extend to insides of two front and rear leg portions 12, 12.
According to this, by combining the core member 411A configured by the wire rod and the core member 411B configured by the plate member, it is possible to reinforce the core members 411A, 411B with respect to each other.
Next, a fin according to a fifth embodiment will be described with reference to
As shown in
The core member 511 in the present embodiment has two front and rear leg portions and is arranged biasedly toward the surfboard 2 side inside the base member, that is, toward the upper side.
It is noted that in the base member in the fifth embodiment, a member other than the glass cloth 513 may be laminated on both the sides of the core member 511.
Also, the core member in the fifth embodiment is not limited to the plate member but may be, for example, a wire rod as in the first and second embodiments, or may be a combination of a wire rod and a plate member as in the fourth embodiment.
The embodiments of the present invention have been described above with the drawings. However, specific configurations are not limited to these embodiments, and the present invention includes even changes and additions within a range not departing from the scope of the present invention.
For example, the examples in which the wire rod and the plate member are used as the core member are described in the above embodiments. However, the present invention is not limited to this, but the core member may be one in which a plurality of thin wire rods such as piano wires are bundled or one in which wire rods are processed in a net shape or a cloth shape.
Also, the leg portions of the fin may be configured as part of the core member as a whole.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-015421 | Feb 2022 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2023/002078 | 1/24/2023 | WO |
