Surfboard fin mounting structure

Abstract

To easily set a mounting position of a fin according to a user's desire without reducing the rigidity of the fin itself. [Solution] The surfboard fin mounting structure for mounting and fixing a surfboard fin 1 to the surfboard body comprises a fin attachment 2 to which the fin 1 is removably attached, and a fin box 3 fixed to the back surface of the surfboard body, which forms a long gap S in the length direction DL of the surfboard on this back surface, and to which the fin attachment 2 is mounted so that it can move in the length direction DL within the gap S.

Description

[Technical Field]

[0001] The present invention relates to a mounting structure for surfboard fins. [Background technology]

[0002] Generally, surfboards have one to four fins attached to the rear end of the underside of the board. These fins help the board to both move in a straight line and turn.

[0003] There are two types of surfboards: longboards and shortboards. Longboards have one fin attached to the center of the board widthwise, while shortboards often have three fins attached and fixed.

[0004] It is known that changing the fin position in the fore-and-aft direction of a surfboard affects the maneuverability of the surfboard, i.e., the ability of the surfboard to travel straight and turn. Moving the fin forward improves turning ability, while moving it backward improves straightness.

[0005] Therefore, if the position of the fins can be changed and the maneuverability of the surfboard can be adjusted according to the user's preferences and wishes, as well as the practice tasks at hand, it will be possible to meet the user's wishes.

[0006] From this perspective, fins have been proposed that allow the attachment position on the surfboard to be changed in the front-to-rear direction. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6664384 Summary of the Invention [Problem to be solved by the invention]

[0008] In the technology of Patent Document 1, an internal cavity is formed inside the fin body, opening over a predetermined length in the front-to-rear direction on the underside of the fin body. A fin insertion plate that can be inserted into the internal cavity is formed on a base member that is fixed to the surfboard by a mounting block at the bottom.

[0009] The fin insertion plate is then inserted into the internal cavity of the fin body and removably secured to the fin body with a button. By removing the button, the fin insertion plate can be moved back and forth within the internal cavity, allowing the relative position of the fin body to be changed along the length of the surfboard relative to the base member.

[0010] With this technology, the internal cavity only has a dimension (i.e., length dimension) that is less than the width dimension of the fin or fin body in the length direction of the surfboard, so the fin body can only be moved a short distance relative to the base member, which has the disadvantage that it may not be possible to ensure the distance of forward and backward movement desired by the user.

[0011] Furthermore, the configuration in which an internal cavity is formed in a thin fin body and the fin insertion plate portion is inserted into the internal cavity and fixed in place has the disadvantage that it is difficult to ensure sufficient rigidity in the fin body against the water pressure that acts continuously on the fin when actually used underwater, and there is a possibility that the fin may not be able to withstand long-term use.

[0012] Therefore, an object of the present invention is to provide a surfboard fin mounting structure that allows the user to easily set the fin mounting position according to their wishes without reducing the rigidity of the fin itself. [Means for solving the problem]

[0013] In order to solve the above problem, the invention of claim 1 provides a surfboard fin mounting structure for mounting and fixing a surfboard fin to a surfboard body, the structure comprising: a fin attachment to which the fin is detachably attached; and a fin box which is fixed to the underside of the surfboard body, forming a gap which is long in the length direction of the surfboard on the underside, the fin attachment being attached in the gap so as to be movable in the length direction, the fin attachment having a length dimension shorter than the gap and a width dimension which is approximately the same as the width dimension of the gap, forming the gap and having a width dimension which allows the fin attachment to be attached to the fin box while being pressed against the inner side surfaces of the fin boxes which face each other, and a front the fin box has a height dimension such that when the fin attachment is attached, the top surface of the fin attachment and the top surface of the fin box are substantially flush with each other; the fin attachment further has an outer protrusion on its outer surface facing the inner surface that engages with the inner surface so as to be able to guide the fin attachment in the length direction in the gap; the fin attachment is formed in the shape of an elongated rectangular parallelepiped overall, has openings that open in the height direction and through which legs provided on the fin can be inserted and removed, and is configured so that the fin can be attached with the legs inserted into the openings; the fin attachment has fixing means that can fix the fin via the legs inserted into the openings; This is a surfboard fin mounting structure characterized in that the fixing means is composed of a lever operating mechanism that can be manually operated by the surfboard user to attach and detach the fin, and the lever operating mechanism is equipped with a drive member that can be manually operated by the user, and a driven member that can switch between attaching and detaching the fin to the fin attachment in conjunction with the movement of the drive member.

[0014] In the invention described in claim 2, the fin box is configured to be able to be fixed to a hole provided in the back surface of the surfboard body, and when fixed to the hole, the top surface of the fin box and the back surface of the surfboard body are configured to be approximately flush with each other. This is the surfboard fin mounting structure described in claim 1.

[0015] In the invention described in claim 3, the fin attachment is composed of a pair of half members divided in the width direction and connected and joined to each other, the outer protrusions are provided on the lower edge of the outer surface portion of each of the pair of half members, and a pair are provided on both sides of the width direction for the entire fin attachment, and the fin attachment further has a first operating member that can press the outer protrusions against the inner surface portion of the fin box by expanding the lower parts of the pair of half members in the width direction, which is the surfboard fin mounting structure described in claim 1.

[0016] In the invention of claim 4, the fin box is formed in an elongated box shape overall, the gap is formed to be long in the lengthwise direction, grooves are formed along the lengthwise direction at the lower ends of the opposing inner side surfaces, the fin attachment is arranged in the grooves where each of the pair of outer protrusions corresponds, and is guided by the grooves to be slidable in the lengthwise direction, and the first operating member is a screw that, when screwed in, presses against the inner side surfaces of the pair of half members, expanding the lower parts of the pair of half members in the widthwise direction and presses the outer protrusions into engagement with the grooves, thereby fixing the fin attachment to the fin box. Claim 3 This is a mounting structure for a surfboard fin as described above.

[0017] In the invention of claim 5, the fin has, at its lower end, a first leg portion at the front end in the width direction, and a second leg portion spaced apart from the first leg and further rearward in the width direction than the first leg, and the fin attachment has a first leg fixing hole portion into which the first leg can be inserted and a second leg fixing hole portion into which the second leg can be inserted, and has a joining fixing portion formed to separate the first leg fixing hole portion and the second leg fixing hole portion and connecting and joining the pair of half members. Claim 3 This is a mounting structure for a surfboard fin as described above.

[0018] In the invention described in claim 6, the fin is formed with an engagement portion at the front end of the first leg and an abutment surface portion at the rear end of the first leg, and the fin attachment has a pressure-contact member in the joining and fixing portion as the driven member that presses against the abutment surface portion of the first leg inserted into the first leg fixing hole, moving the first leg toward its front end in the first leg fixing hole, and a first locking protrusion is provided at the front end of the first leg fixing hole that releasably engages with the engagement portion, which is the surfboard fin mounting structure described in claim 5.

[0019] In the invention of claim 7, the fin attachment is configured to be switchable at the joining and fixing portion between a first position in which the pressure contact member protrudes into the first leg fixing hole portion and presses against the abutment surface portion, and a second position in which the pressure contact member retracts from the first leg fixing hole portion and releases the pressure contact with the abutment surface portion, a second operating member is provided as the drive member, and the fin is attached to the fin attachment, and when the fin attachment is attached, the first leg is in the first leg fixing hole portion, the second operating member is positioned at the first position, the first locking protrusion engages with the engagement portion, and the pressure contact member presses against the abutment surface portion, the surfboard fin mounting structure of claim 6 is characterized in that

[0020] In the invention described in claim 8, the fin has an engagement recess formed on the side portion of the second leg facing the thickness direction of the fin, and the fin attachment has a second engagement protrusion in the second leg fixing hole portion that releasably engages with the engagement recess, and when the fin attachment is attached, the second leg is inserted into the second leg fixing hole portion and the second engagement protrusion is engaged with the engagement recess, thereby fixing the fin to the fin attachment, which is the surfboard fin mounting structure described in claim 6. [Effects of the Invention]

[0021] According to the invention described in claim 1, the fin attachment, to which the fin is removably attached, is configured to be attached and fixed to the fin box fixed to the underside of the surfboard body in the gap therebetween so that it can move in the longitudinal direction of the surfboard.

[0022] This allows the user to position the fin on the underside of the surfboard body in an appropriate position according to their preferences and desires.

[0023] Here, there is no gap inside the fin to allow movement of the fin in the length direction of the surfboard (hereinafter sometimes referred to as "forth and back movement of the fin"), and the fin itself is attached to the fin box via a fin attachment and fixed to the underside of the surfboard body.

[0024] This makes it possible to solve the conventional problem that the structure is weak against the water pressure applied to the fins during use and may not be able to withstand long-term use.

[0025] Furthermore, according to the invention described in claim 1, since the fin attachment is formed to have a length dimension shorter than the gap portion, the user can move the fin along the fin box in the length direction of the surfboard over a length dimension greater than or equal to the width of the fin and place it in the desired position.

[0026] This allows the fins to be moved to a position closer to the user's preference.

[0027] Furthermore, according to the invention described in claim 1, the fin attachment is provided with an opening that opens in the vertical direction, and the fin is configured to be attached to the fin attachment with the legs provided on the fin inserted into this opening.

[0028] This makes it possible to attach the fin to the fin attachment from the outside of the fin attachment via the legs of the fin, allowing the user to easily attach the fin to the fin attachment.

[0029] According to the invention as recited in claim 1, the fixing means is configured to fix the fin to the fin attachment via the leg portion inserted into the opening.

[0030] This makes it easier to secure the fin to the fin attachment. Furthermore, the invention described in claim 1 has a fixing means constituted by a lever operating mechanism that can be manually operated by the surfboard user to attach and detach the fin, and the lever operating mechanism is equipped with a drive member that can be manually operated by the user and a driven member that can switch between attaching and detaching the fin to the fin attachment in conjunction with the movement of the drive member, making it easy for the user to attach and detach the fin.

[0031] Furthermore, according to the invention described in claim 2, the fin box is configured to be able to be fixed to a hole provided on the underside of the surfboard body, and when the fin box is fixed to the hole, the top surface of the fin box and the underside of the surfboard body are approximately flush with each other, and the top surface of the fin attachment and the top surface of the fin box are also approximately flush with each other.

[0032] This means that when the fin attachment is removed from the fin box, the underside of the surfboard body becomes flat and free of protrusions, making it possible to avoid situations that would hinder transportation, such as when transporting the surfboard to a beach where surfing is to be performed, due to protrusions remaining on the underside of the surfboard body making it difficult to transport.

[0033] According to the invention described in claim 3, the fin attachment is divided in the width direction and is composed of a pair of half members joined and fixed to each other, and a first operating member provided on the fin attachment is configured to expand the lower parts of the pair of half members in the width direction and press the outer protrusions of each member against the inner surface portion of the fin box.

[0034] This allows the user to easily secure the fin attachment to the fin box by operating the first operating member.

[0035] According to the invention described in claim 4, the fin box has a cavity formed in the longitudinal direction of the surfboard, and the outer protrusion of the fin attachment is arranged in a groove formed along the longitudinal direction at the lower end of the opposing inner surface portions, so that the fin attachment is guided by the groove and can slide in the longitudinal direction.

[0036] This allows the user to smoothly slide the fin attachment in the gap of the fin box, and easily change and adjust the attachment position of the fin.

[0037] Furthermore, by screwing in the first operating member, which is a screw, the first operating member is pressed against the inner surface portions of the pair of half members, thereby expanding the lower portions of the pair of half members in the width direction and fastening the outer protrusion of the fin attachment to the groove portion of the fin box with pressure.

[0038] This allows users to easily and quickly change the fin attachment position depending on the training theme when using a surfboard, such as when maneuverability is required (for example, when practicing turns) or when straight-line stability is required (for example, when practicing high-speed riding).

[0039] According to the invention described in claim 5, the fin attachment is formed with a first leg fixing hole portion at the front and a second leg fixing hole portion at the rear, sandwiching the joining fixing portion that connects and joins a pair of half members, and is configured so that the first leg of the fin is inserted into the first leg fixing hole and the second leg is inserted into the second leg fixing hole.

[0040] This makes it possible to securely fix the fin to the fin box via the fin attachment while ensuring the strength required for the fin attachment.

[0041] According to the invention described in claim 6, the abutment surface of the first leg accommodated in the first leg fixing hole is pressed by the pressure-contact member of the fin attachment, moving the first leg toward its front end in the first leg fixing hole, and engaging the first locking protrusion provided at the front end of the first leg fixing hole with the engaging portion provided at the front end of the first leg to fix the fin.

[0042] This makes it possible to easily and reliably attach a fin, which has a front end and a rear end at the lower end of the first leg and an engagement portion at the front end, to the fin attachment and fix it to the underside of the surfboard body so that it can move along the length of the surfboard.

[0043] According to the invention described in claim 7, the second operating member is configured to be switchable between a first position in which the pressure member is pressed against the abutment surface portion of the first leg portion of the fin, and a second position in which the pressure member is retracted and the pressure against the abutment surface portion is released, making it possible to attach and detach the fin to and from the fin attachment using the second operating member, and is configured so that when the fin attachment is attached, the first locking protrusion of the fin attachment engages with the engaging portion of the first leg portion.

[0044] This allows the fin to be securely attached to the fin attachment, and also allows the user to easily switch between attaching and detaching the fin to and from the fin attachment by operating the second operating member.

[0045] According to the invention described in claim 8, in the fin attachment, a second locking protrusion is formed in the second leg fixing hole portion, and when the fin attachment is attached, the second locking protrusion is configured to engage with the engagement recess of the second leg portion.

[0046] This allows the fin to be securely supported against the underside of the surfboard body when the fin is fixed to the fin attachment via both the first leg and the second leg and the fin attachment is attached to the fin box. [Brief explanation of the drawings]

[0047] [Figure 1] 1 is a perspective view showing a fin and its mounting structure according to an embodiment of the present invention, viewed from diagonally above and behind the left. [Figure 2] 2 is a perspective view showing the fin and its mounting structure shown in FIG. 1, as viewed obliquely from above on the left. [Figure 3] FIG. 2 is a perspective view showing the fin and fin attachment shown in FIG. 1 removed from the fin box. [Figure 4] 4 is a cross-sectional view of the fin and fin attachment shown in FIG. 3 taken along line A-A in FIG. 1, showing the lever operating mechanism in the drive member mounting position. [Figure 5] 4 is a cross-sectional view of the fin and fin attachment shown in FIG. 3 taken along line BB in FIG. 1, showing the lever operating mechanism in a position where the drive member is attached. [Figure 6] FIG. 4 is a bottom view of the fin and fin attachment shown in FIG. 3. [Figure 7] 2 is a plan view of a fin attachment provided in the fin mounting structure shown in FIG. 1. FIG. [Figure 8] 8A and 8B are exploded perspective views of the fin attachment shown in FIG. 7, where (a) shows the left half member of the fin attachment as viewed from the upper right rear, and (b) shows the same left half member as viewed from the upper left front. [Figure 9] 2 is a plan view of a fin box provided in the fin mounting structure shown in FIG. 1. FIG. [Figure 10] FIG. 10 is a side view of the fin box shown in FIG. [Figure 11] 11 is a cross-sectional view of the fin box taken along line CC shown in FIG. 10. [Figure 12] FIG. 1 is a schematic diagram showing the fin mounting positions on a surfboard, taking as an example a five-fin specification where five fins can be mounted. DETAILED DESCRIPTION OF THE INVENTION

[0048] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0049] As shown in Figure 1, the mounting structure for a surfboard fin (hereinafter simply referred to as "fin") 1 according to one embodiment of the present invention is for mounting and fixing the fin 1 to a surfboard body (not shown). The mounting structure for the fin 1 according to this embodiment (hereinafter simply referred to as "mounting structure") has, as its main elements, a fin attachment 2 and a fin box 3.

[0050] The fins 1 are attached to the underside of the surfboard body to provide or improve the maneuverability of the surfboard, specifically, its ability to travel straight and turn. The surfboard to which the fins 1 are attached may be a longboard or a shortboard, and the number and attachment positions are determined depending on the maneuverability required.

[0051] For example, a longboard has a single center fin attached to the center of the rear end of the underside of the surfboard body, while a shortboard has a single center fin and a pair of side fins, one on each side. The attachment structure can be applied to both center fins and side fins.

[0052] In each of Figures 1 to 3, the length direction of the surfboard is indicated by an arrow DL, the width direction of the surfboard is indicated by an arrow DW, and the thickness direction is indicated by an arrow DT.

[0053] In FIG. 1, the back surface of the surfboard faces upward on the paper, and the front surface faces downward on the paper.

[0054] When the fin 1 is attached to a surfboard, its width direction corresponds to the length direction DL of the surfboard, and its thickness direction and height direction correspond to the width direction DW and thickness direction DT of the surfboard, respectively.

[0055] As shown in FIGS. 4 and 5, the fin 1 to be attached by the attachment structure has legs 12 and 13 that protrude from the lower end 11 in the height direction of the fin 1.

[0056] In this embodiment, the legs 12, 13 include a front leg 12 provided at one end of the fin 1 in the width direction (in other words, the front end in the longitudinal direction DL of the surfboard), and an intermediate leg 13 provided at a distance from the front leg 12 toward the other end of the fin 1 in the width direction.

[0057] Here, the front leg 12 corresponds to the "first leg" according to this embodiment, and the middle leg 13 corresponds to the "second leg" according to this embodiment.

[0058] To attach to the fin attachment 2, the front end of the front leg 12 is provided with an engagement portion 121 that protrudes forward in the length direction DL and is split into upper and lower forks, and one side of the middle leg 13 that faces the width direction DW of the surfboard (i.e., the thickness direction of the fin 1) is formed with an engagement recess 131 that is recessed in the width direction DW (Figure 5).

[0059] The engaging portion 121 and the engaging recess 131 have their edges defined by the legs 12, 13 at the top, bottom, and rear, while being open toward the front.

[0060] 1 to 3, the fin 1 is removably attached to the fin attachment 2. The fin attachment 2 is removably attached to the fin box 3 (described below), and by attaching the fin attachment 2 to the fin box 3 with the fin 1 attached, the fin 1 can be attached and fixed to the underside of the surfboard body via the fin box 3.

[0061] The fin box 3 is fixed to the underside of the surfboard body. In this embodiment, a long hole (not shown) is provided in the underside of the surfboard body in the length direction DL, and the fin box 3 is embedded in this hole and fixed in place with adhesive or the like.

[0062] 9 and 10, the fin box 3 has an overall long box shape, and when fixed to the underside of the surfboard body, it forms a long, narrow gap S on the underside that runs along the length direction DL of the surfboard. The gap S can accommodate the fin attachment 2 with the fin 1 attached.

[0063] 1 and 2, the fin attachment 2 has a dimension in the length direction DL that is shorter than the gap S. In other words, when the fin attachment 2 is housed in the gap S, a gap is formed in front of or behind the fin attachment 2 in the length direction DL that allows the fin attachment 2 to move relative to the fin box 3. In other words, when the fin attachment 2 is attached to the fin box 3, the gap S can move in the length direction DL of the surfboard.

[0064] The fin attachment 2 has dimensions in the width direction DW that are approximately the same as the gap S. In other words, the width dimension of the fin attachment 2 and the width dimension of the gap S are approximately the same, and when the fin attachment 2 is attached to the fin box 3, the outer side surface portions 21 (21l, 21r) in the width direction DW are pressed against the inner side surface portions 31 (31l, 31r) of the fin box 3. The inner side surface portions 31 face each other in the width direction DW and define the gap S together with the front and rear surface portions.

[0065] The fin attachment 2 has dimensions in the thickness direction DT that are approximately the same as the gap S, and when it is contained in the gap S and attached to the fin box 3, its upper surface 22 is approximately flush with the upper surface 32 of the fin box 3.

[0066] The dimension of the fin box 3 in the thickness direction DT (i.e., the height dimension) is set so that the top surface 32 of the fin box 3 is roughly flush with the underside of the surfboard body when the fin box 3 is fitted into the hole in the surfboard body. Therefore, the top surfaces 22, 32 of the fin attachment 2 and fin box 3 are aligned at roughly the same height in the thickness direction DT relative to the underside of the surfboard body.

[0067] 3, the fin attachment 2 has outer protrusions 211f, 211b that engage with the inner surface portion 31 on the left and right outer surface portions 21l, 21r that face the inner surface portion 31 of the gap S. The outer protrusions 211f, 211b are provided on the lower end of the fin attachment 2 at the front end portion 23 and the rear end portion 24 of the fin attachment 2, respectively, and protrude outward in the width direction DW from the outer surface portions 21l, 21r.

[0068] 11, in this embodiment, grooves 311 (311l, 311r) are formed in the fin box 3 along the length direction DL of the surfboard at the lower end of each of a pair of inner side surfaces 31l, 31r that define the gap S. Outer protrusions 211f, 211b of the fin attachment 2 engage with these pair of grooves 311l, 311r, restricting movement of the fin attachment 2 relative to the fin box 3 in the thickness direction DT.

[0069] The fin attachment 2 is guided in the longitudinal direction DL as the outer protrusions 211f, 211b move along the corresponding grooves 311l, 311r, and slides through the gap S in the longitudinal direction DL toward the front end 33 or rear end 34 of the fin box 3.

[0070] 7 and 8, the fin attachment 2 has an overall elongated rectangular parallelepiped shape and has an opening O that opens in the thickness direction DT of the surfboard (i.e., the height direction of the fin 1 or fin attachment 2). The fin 1 can be attached to the fin attachment 2 with the legs 12, 13, which protrude from the bottom surface of the lower end 11 in the height direction (i.e., the thickness direction DT of the surfboard), inserted into this opening O.

[0071] In order to allow the fin 1 to be freely attached and detached to the fin attachment 2, a lever operation mechanism is provided that allows the surfboard user to manually attach and detach the fin 1.

[0072] A user can attach the fin 1 to the fin attachment 2 and detach the fin 1 from the fin attachment 2 by operating the drive member 41 of the lever operation mechanism with his or her fingers.

[0073] The lever operating mechanism corresponds to the "fixing means" according to this embodiment.

[0074] The configuration of the fin attachment 2 will now be further described with reference to FIGS.

[0075] In this embodiment, the fin attachment 2 is divided in the width direction DW into a pair of half members 2A, 2B, and the fin attachment 2 is formed by joining the pair of half members 2A, 2B together.

[0076] The pair of half members 2A, 2B includes a left half member 2A on the left side of the width direction DW toward the front of the surfboard and a right half member 2B on the right side, and the left half member 2A and the right half member 2B are connected and joined via an intermediate wall portion 25 formed in the middle of the length direction DL with their inner surface portions facing each other.

[0077] Here, the intermediate wall portion 25 corresponds to the "joint fixing portion" according to this embodiment.

[0078] As described above, the left half member 2A and the right half member 2B have the aforementioned outer side surface portions 21l, 21r on the opposite sides of their inner side surface portions, and a pair of outer protrusions 211f, 211b is formed on the lower end of each of the outer side surface portions 21l, 21r. That is, in this embodiment, a pair of outer protrusions 211f, 211b is provided on the outer side surface portion 21l of the left half member 2A, and a pair of outer protrusions 211f, 211b is provided on the outer side surface portion 21r of the right half member 2B, so that the fin attachment 2 as a whole has a total of four outer protrusions 211f, 211b at the front end 23 and the rear end 24.

[0079] The left half member 2A and the right half member 2B have inward protrusions 231, 241 at their front end 23 and rear end 24, respectively, which protrude from the inner surface of one member toward the inner surface of the other member. The inward protrusions 231l, 241l of the left half member 2A and the inward protrusions 231r, 241r of the right half member 2B (Figure 6) are staggered in the thickness direction DT, and partially overlap each other in the thickness direction DT (specifically, the inner ends near the inner surface of the other member).

[0080] Here, in the fin attachment 2, a hole portion (hereinafter referred to as the "first leg fixing hole portion") O1 is formed which is defined in the length direction DL by the inward protrusions 231l, 231r of the front end portion 23 and the intermediate wall portion 25 and which passes through the fin attachment 2 in the thickness direction DT. Furthermore, a hole portion (hereinafter referred to as the "second leg fixing hole portion") O2 is formed which is defined in the length direction DL by the inward protrusions 241l, 241r of the rear end portion 24 and the intermediate wall portion 25 and which passes through the fin attachment 2 in the thickness direction DT.

[0081] When the fin 1 is attached to the fin attachment 2, the front leg 12 of the fin 1 is inserted into the first leg fixing hole O1, and the middle leg 13 of the fin 1 is inserted into the second leg fixing hole O2.

[0082] Of the inward protrusions 231, 241 provided on the left and right half members 2A, 2B, the inward protrusions closest to the upper surface 22 of the fin attachment 2 (in this embodiment, the inward protrusions 231l, 241l of the left half member 2A) have embedded screws 51, 52 provided at the front end 23 and rear end 24 of the fin attachment 2, respectively.

[0083] As shown in Figure 6, the screws 51 and 52 are positioned so that their tips can enter between the inner surface of the left half member 2A and the inner protrusions 231r and 241r of the right half member 2B, and by screwing the screws 51 and 52 into the inner protrusions 231l and 241l, the lower part of the left half member 2A and the lower part of the right half member 2B can be separated in the width direction DW, and the fin attachment 2 can be expanded in the width direction DW at its lower part.

[0084] Here, the screw 51 at the front end portion 23 and the screw 52 at the rear end portion 24 each correspond to a "first operating member" according to this embodiment.

[0085] The lever operating mechanism is provided on the intermediate wall portion 25 of the fin attachment 2.

[0086] The lever operation mechanism includes a drive member 41 that can be manually operated by a user, and a driven member 42 that can switch between attaching and detaching the fin 1 to the fin attachment 2 in conjunction with the movement of the drive member 41. The drive member 41 and the driven member 42 are coupled to each other so that they can be moved in conjunction with each other. In this embodiment, the drive member 41 and the driven member 42 are coupled via a connecting shaft portion 422 (FIG. 8) formed on the driven member 42, and can rotate together about an axis AX that extends in the width direction DW.

[0087] The drive member 41 is rotatable about an axis AX and can be switched between an attached position and an detached position shown in Fig. 3. The attached position corresponds to the "first position" according to this embodiment, and the detached position corresponds to the "second position" according to this embodiment.

[0088] When the driving member 41 is in the release position, the tip 411 protrudes from the upper surface 22 of the fin attachment 2. In this case, the driven member 42 is in a position rotated in the same direction and by the same angle as the driving member 41 from the state shown in FIG.

[0089] 8, with the tip 421 separated from the intermediate wall 25 of the fin attachment 2 and protruding into the first leg fixing hole O1. In this state, the driven member 42 presses against the rear end of the front leg 12 of the fin 1, pushing the front leg 12 forward and moving the front leg 12 toward its front end in the first leg fixing hole O1. In other words, the rear end of the front leg 12 forms the "contact surface" 122 according to this embodiment.

[0090] The fin attachment 2 has a first locking protrusion 26 formed at the front end of the first leg fixing hole O1 that is capable of engaging with the engaging portion 121 of the front leg 12. In this embodiment, the inner protrusion 231l of the left half member 2A of the fin attachment 2 extends further rearward in the longitudinal direction DL than the inner protrusion 231r of the right half member 2B, and the first locking protrusion 26 that can fit into the forked engaging portion 121 is formed at its rear end.

[0091] Here, the driving member 41 corresponds to the "second operating member" according to this embodiment, and the driven member 42 corresponds to the "pressure contact member" according to this embodiment.

[0092] The following describes a series of steps for attaching and fixing the fin 1 to the underside of the surfboard body. Attaching the fin 1 includes a first step of attaching the fin 1 to the fin attachment 2, and a second step after the first step of attaching the fin attachment 2 with the fin 1 attached to the fin box 3.

[0093] In the first step, with the fin attachment 2 having the drive member 41 in the release position, the front leg 12 of the fin 1 is inserted into the first leg fixing hole O1 and the middle leg 13 is inserted into the second leg fixing hole O2. In this state, the bottom end 11 of the fin 1 abuts against the top surface 22 of the fin attachment 2.

[0094] Next, the driving member 41 is rotated around the axis AX and tilted backward to move it to the mounting position, and the driven member 42 is rotated in conjunction with the driving member 41 and protrudes into the first leg fixing hole O1. This causes the driven member 42 to press against the rear end of the front leg 12, and the driven member 42 presses against the contact surface 122, moving the front leg 12 and the fin 1 forward.

[0095] When the front leg 12 reaches the vicinity of the front end of the first leg fixing hole O1, the first locking protrusion 26 of the fin attachment 2 fits into the engagement portion 121 of the front leg 12. This causes the first locking protrusion 26 to restrict movement of the fin 1 in the height direction (i.e., the thickness direction DT of the surfboard) relative to the fin attachment 2.

[0096] In addition to the above, in this embodiment, a second locking protrusion 27 that protrudes inward into the second leg fixing hole O2 is provided on the inner surface of the right half member 2B (FIG. 7).

[0097] The second locking protrusion 27 moves away from the engagement recess 131 of the middle leg 13 when the drive member 41 is in the release position and the rear leg 13 is in a position close to the rear end of the second leg fixing hole O3, but when the drive member 41 is switched to the attachment position and the middle leg 13 approaches the front end of the second leg fixing hole O2, it engages with the engagement recess 131 and, like the first locking protrusion 26, restricts the vertical movement of the fin 1 relative to the fin attachment 2.

[0098] Thus, the first step is completed.

[0099] Following the first step, the fin attachment 2 with the fin 1 attached thereto is housed in the space S of the fin box 3.

[0100] Next, the fin attachment 2 is moved in the length direction DL in the gap S, and placed in an appropriate position according to the user's preferences and wishes, as well as the practice task at hand. As the fin attachment 2 moves, the outward protrusions 211f, 211b on the outer side surfaces 21l, 21r engage with the grooves 311l, 311r inside the fin box 3, and the fin attachment 2 is guided by the grooves 311l, 311r.

[0101] Thereafter, the screws 51, 52 at the front end 23 and the rear end 24 are screwed in to separate the lower part of the left half member 2A from the lower part of the right half member 2B in the width direction DW, and the fin attachment 2 is spread apart in the width direction DW at its lower part. As a result, the outer side surfaces 21l, 21r of the fin attachment 2 are pressed against the inner side surfaces 31l, 31r of the fin box 3, and the outer protrusions 211f, 211b are pressed into engagement with the grooves 311l, 311r, and the fin attachment 2 is fixed to the fin box 3.

[0102] The screws 51 and 52 can be easily screwed in using a predetermined tool such as a small hexagonal wrench.

[0103] Thus, according to this embodiment, the fin attachment 2 to which the fin 1 is removably fixed is configured to be fixed to the fin box 3 fixed to the underside of the surfboard body in a gap S so that it can move in the length direction DL of the surfboard. This makes it possible to position the fin 1 on the underside of the surfboard body at an appropriate position according to the user's preferences and wishes, and adjust the maneuverability of the surfboard.

[0104] Here, there is no gap S inside the fin 1 that would allow movement of the fin 1 in the longitudinal direction DL (i.e., back and forth movement of the fin), and the fin 1 is attached to the fin attachment 2, attached to the fin box 3 via the fin attachment 2, and fixed to the back surface of the surfboard body, thereby ensuring the rigidity of the fin 1 and making it possible to create a structure that can withstand long-term use.

[0105] Furthermore, the fin box 3 can be fixed into a hole provided on the underside of the surfboard body, and when the fin box 3 is fixed into this hole, the top surface 32 of the fin box 3 and the underside of the surfboard body are approximately flush, and the top surface 22 of the fin attachment 2 and the top surface 32 of the fin box 3 are also approximately flush.This means that when the fin attachment 2 is removed from the fin box 3, the underside of the surfboard body is flat and free of protrusions, which makes it possible to avoid problems that would hinder transportation when transporting the surfboard to a beach where surfing is to be done, such as protrusions remaining on the underside of the surfboard body making it difficult to transport.

[0106] In the case of a multi-fin specification using multiple fins 1, the orientation of the fin attachment 2 when attached to the surfboard body can be the same for all fins 1, or it can be different for some fins 1 than for other fins 1. Specifically, the positions of the drive member 41 and screws 51, 52 relative to the center of the surfboard body in the width direction DW are made different among the multiple fins 1.

[0107] For example, the drive member 41 and screws 51, 52 of the fin attachment 2 are disposed on the outside relative to the center of the surfboard body SB.

[0108] With reference to FIG. 12, an example of a five-fin specification in which five fins 1 are used will be described.

[0109] In the example shown in the figure, five fins 1 are attached to the underside of the surfboard body SB using an attachment structure. Here, the assembly of the fins 1, fin attachment 2, and fin box 3 is called a "fin assembly" ASY (ASY1 to ASY5), and in Figure 12, the five fin assemblies ASY1 to ASY5 are arranged staggered back and forth.

[0110] Specifically, a first fin assembly ASY1 is positioned in the center of the rear end of the underside of the surfboard body SB, and a pair of fin assemblies (second fin assembly ASY2, third fin assembly ASY3) are positioned forward of the first fin assembly ASY1, sandwiching the center of the surfboard body SB from the left and right, and further forward than that, a pair of fin assemblies (fourth fin assembly ASY4, fifth fin assembly ASY5) are positioned shifted outward from the second and third fin assemblies ASY2, ASY3.

[0111] Of these five fin assemblies ASY1 to ASY5, the second and fourth fin assemblies ASY2 and ASY4 lined up on the left side are arranged with the half member 2A including the drive member 41 on the left side so that the drive member 41 and the screws 51 and 52 are located to the left of the fin 1. Figure 12(a) shows the second and fourth fin assemblies ASY2 and ASY4 with the fin 1 removed.

[0112] On the other hand, the third and fifth fin assemblies ASY3 and ASY5, which are aligned on the right side, are arranged with the half member 2A on the right side so that the drive member 41 and the screws 51 and 52 are located to the right of the fin 1. Figure 12(b) shows the third and fifth fin assemblies ASY3 and ASY5 with the fin 1 removed.

[0113] The first fin assembly ASY1 at the center of the rear end can be oriented in either direction, and in the example shown in Figure 12, it is shared with the second and fourth fin assemblies ASY2 and ASY4, and is arranged so that the drive member 41 and screws 51 and 52 are located to the left of the fin 1.

[0114] The above-described embodiments are merely illustrative and do not limit the scope of the invention. These novel embodiments may be embodied in various other forms, and various omissions, substitutions, or modifications may be made without departing from the spirit of the invention. These embodiments and modifications thereof are included within the scope and spirit of the invention, and are also included in the scope of the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0115] 1. Fin 11...Lower end of fin 12...Front leg (first leg) 121...Engagement portion 122...Abutment surface part 13…Middle leg (second leg) 131...engagement recess 2...Fin attachment 2A...Left half member 2B...Right half member 21, 21l, 21r...Outer surface of fin attachment 211f, 211b...External process 22...Top surface of fin attachment 23...Front end 24...Rear end 25…Intermediate wall part (joint fixing part) 26...First locking convex part 27…Second locking protrusion O...Opening O1...First leg fixing hole O2…Second leg fixing hole 41, 42... Lever operating mechanism (fixing means) 41...Drive member (second operating member) 411...Tip 42...Driven member (pressure-contact member) 421...Tip 422...Connection shaft part 51, 52...Screw (first operating member) 3. Fin box 31, 31l, 31r...Inner surface of the fin box 311l, 311r…Groove 32...Top of fin box S...Void part AX…Axis SB…Surfboard body ASY, ASY1 to ASY5...Fin assembly

Claims

1. A surfboard fin mounting structure for mounting and fixing a surfboard fin to a surfboard body, a fin attachment to which the fin is detachably attached; a fin box that is fixed to the back surface of the surfboard body to form a gap that is long in the length direction of the surfboard on the back surface, and the fin attachment is attached to the gap so that it can move in the length direction, the fin attachment has a length dimension shorter than the gap and a width dimension substantially the same as the width dimension of the gap, and has a width dimension that allows the fin attachment to be attached to the fin box in a state of being in pressure contact with the inner side surfaces of the fin box that form the gap and face each other, the fin box has a height dimension such that, when the fin attachment is attached, an upper surface of the fin attachment and an upper surface of the fin box are substantially flush with each other; the fin attachment further has an outer protrusion on an outer surface portion facing the inner surface portion, the outer protrusion engaging with the inner surface portion so as to be able to guide the fin attachment in the length direction in the gap portion; the fin attachment is formed in an elongated rectangular parallelepiped shape overall, has an opening in a height direction, and has an opening through which a leg portion provided on the fin can be inserted and removed, The fin is configured to be attachable with the leg portion inserted into the opening, the fin attachment has a fixing means capable of fixing the fin via the leg portion inserted into the opening, The fixing means is configured with a lever operating mechanism that can be manually operated by a surfboard user to attach and detach the fin, A surfboard fin mounting structure characterized in that the lever operating mechanism comprises a drive member that can be manually operated by the user and a driven member that can switch between attaching and detaching the fin to the fin attachment in conjunction with the movement of the drive member.

2. The fin box is configured to be fixed to a hole provided on the back surface of the surfboard body, 2. The surfboard fin mounting structure according to claim 1, characterized in that, when fixed to the hole, the top surface of the fin box and the underside of the surfboard body are configured to be approximately flush with each other.

3. The fin attachment is composed of a pair of half members that are divided in the width direction and connected and joined to each other, the outer protrusions are provided on the lower edge of the outer surface portion of each of the pair of half members, and a pair of outer protrusions are provided on both sides in the width direction of the fin attachment as a whole; 2. The surfboard fin mounting structure according to claim 1, wherein the fin attachment further comprises a first operating member that can press the outer protrusion against the inner surface of the fin box by expanding the lower portions of the pair of half members in the width direction.

4. The fin box is formed in an elongated box shape overall, and the gap is formed long in the length direction, A groove is formed in the lower end of each of the inner side surfaces facing each other along the length direction, The fin attachment is configured such that each of the pair of outer protrusions is disposed in the corresponding groove, and is slidable in the length direction while being guided by the groove; 4. The surfboard fin mounting structure of claim 3, wherein the first operating member is a screw that, when screwed in, presses against the inner surface portions of the pair of half members, expanding the lower portions of the pair of half members in the width direction and presses the outer protrusion into the groove portion, thereby fixing the fin attachment to the fin box.

5. The fin has a first leg portion at a front end portion in the width direction at a lower end portion thereof, and a second leg portion spaced apart from the first leg portion and further rearward in the width direction than the first leg portion, the fin attachment has a first leg fixing hole into which the first leg can be inserted and a second leg fixing hole into which the second leg can be inserted, 4. The surfboard fin mounting structure according to claim 3, further comprising a joining and fixing portion formed to separate the first leg fixing hole portion and the second leg fixing hole portion, which connects and joins the pair of half members.

6. The fin has an engagement portion formed at the front end of the first leg and an abutment surface portion formed at the rear end of the first leg, the fin attachment has a pressure member in the joining and fixing portion as the driven member that presses against the contact surface of the first leg inserted into the first leg fixing hole, thereby moving the first leg toward its front end in the first leg fixing hole; 6. The surfboard fin mounting structure according to claim 5, wherein a first locking protrusion is provided at a front end of the first leg fixing hole portion, the first locking protrusion being capable of being engaged with and disengaged from the engaging portion.

7. The fin attachment is configured so that, at the joint fixing portion, it can be switched between a first position in which the pressure contact member is protruded into the first leg fixing hole portion and pressed against the abutment surface portion, and a second position in which the pressure contact member is retracted from the first leg fixing hole portion and the pressure contact with the abutment surface portion is released, and a second operating member is provided as the driving member, the fin is attached to the fin attachment; when the fin is attached to the attachment, the first leg is in the first leg fixing hole and the second operating member is disposed at the first position; 7. The surfboard fin mounting structure according to claim 6, wherein the first locking projection engages with the engaging portion, and the pressure contact member presses against the abutment surface portion.

8. The fin has an engaging recess formed on a side surface of the second leg portion facing in the thickness direction of the fin, the fin attachment is provided with a second locking protrusion in the second leg fixing hole that is releasably engaged with the engaging recess; 7. A surfboard fin mounting structure as described in claim 6, characterized in that when attaching the fin attachment, the second leg is inserted into the second leg fixing hole and the second locking protrusion is engaged with the engagement recess, thereby fixing the fin to the fin attachment.

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