Commutator and oar

Abstract

To provide a commutator and an oar equipped with a commutator that makes the oar easy to operate. The commutator 1 is an elongated commutator fixed to the blade 100 of the oar 200 to rectify the flow of water, characterized in that it protrudes from the front surface 101 of the blade 100 and is fixed with its tip side inclined upward. Also, the commutator 2 is characterized in that it protrudes from the back surface 102 of the blade 100 and is fixed with its tip side inclined downward. Also, in the vertical cross section, it protrudes most below the middle, and in the longitudinal direction, the protruding length L1 from the blade 100 is maximum at the middle and extends toward both sides. To As the blade 100 is viewed in the vertical direction, the upper surface 11 formed on the upper side is inclined with respect to the blade 100 and has an arch shape that protrudes upward.

Description

[Technical field]

[0001] The present invention relates to a commutator and an oar. [Background technology]

[0002] An oar for rowing comprises a long, thin cylindrical shaft, a blade fixed to the tip of the shaft, a handle fixed to the base end of the shaft, and a sleeve fitted onto the base end side of the shaft (see Patent Document 1). The sleeve is inserted into a rowlock (oarlock, oar receiver) on the boat (hull) and is supported by the rowlock. The rower grips the handle and operates the oar with the rowlock as the fulcrum. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-137205 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, depending on the skill of the rower, the water surface conditions, and other factors, it can be difficult to operate the oars.

[0005] Therefore, an object of the present invention is to provide a commutator that makes it easier to operate an oar and an oar equipped with a commutator. [Means for solving the problem]

[0006] As a means for solving the above problems, the present invention provides an elongated commutator that is fixed to an oar blade and rectifies the flow of water, comprising: The blade extends in an axial direction of the oar and has a longitudinal direction and a width direction perpendicular to the longitudinal direction. The blade Grab the water As well as protruding from the surface, The width direction is the vertical direction, and the length direction is the outer side. The tip is fixed at an upward incline. , the cross section in the vertical direction when the width direction is the vertical direction. This commutator is characterized in that in a vertical cross section, it protrudes most downward from the middle.

[0007] With this configuration, the commutator protrudes from the surface (front) of the blade and the tip side is fixed at an upward incline, so that when catching, water that penetrates (enters) the surface side of the blade from the tip side pushes the commutator and the blade vertically upward. This makes it difficult for the blade to sink in the water when catching, making it easier to operate the oar.

[0008] As a means for solving the above problems, the present invention provides an elongated commutator that is fixed to an oar blade and rectifies the flow of water, comprising: The blade extends in an axial direction of the oar and has a longitudinal direction and a width direction perpendicular to the longitudinal direction. The blade The opposite of the surface that grabs water It protrudes from the back and The width direction is the vertical direction, and the length direction is the outer side. The tip is fixed at a downward angle. , the cross section in the vertical direction when the width direction is the vertical direction. This commutator is characterized in that in a vertical cross section, it protrudes most downward from the middle.

[0009] With this configuration, the commutator protrudes from the back side (rear side) of the blade, and the tip side is fixed at a downward incline, so that when finishing, water that enters the back side of the blade from the base side pushes the commutator and the blade vertically upward. This makes it difficult for the blade to sink in the water when finishing, making it easier to operate the oar. In other words, it makes it difficult to commit a so-called harakiri. An example of an instance where water that has entered the back side of the blade pushes up the commutator is when, in a crew boat (eight, quadruple, coxed four, etc.), the operation of the oar (blade) is slower than the water flow corresponding to the boat speed, and the water pushes against the back side of the blade.

[0011] Here, the vertical section refers to a section of the commutator in the vertical direction (longitudinal direction) when the width direction of the blade to which the commutator is fixed is the vertical direction (longitudinal direction). With this configuration, in the vertical section of the commutator, the commutator protrudes most downward rather than in the middle, so that the angle between the lower surface below the most protruding position and the front / back surface of the blade is larger than the angle between the upper surface above the most protruding position and the front / back surface of the blade.

[0012] In this way, because the angle between the underside and the front / rear surface of the blade is large, when the commutator is fixed to the front surface of the blade, water entering the front surface of the blade from the tip side during catch tends to push the commutator and the blade vertically upwards. Also, when the commutator is fixed to the rear surface, water entering the rear surface of the blade from the base end tends to push the commutator and the blade vertically upwards during finish.

[0013] Also, The commutator In the longitudinal direction, the protruding length from the blade is maximum at the middle and extends outward on both sides. To The upper surface formed on the upper side may be oblique to the blade and have an upwardly protruding arch shape when viewed in the vertical direction of the blade.

[0014] According to this configuration, the length of the protrusion from the blade in the longitudinal direction is maximum at the middle and extends toward both sides. To As the blade length increases, it gradually becomes shorter, and the upper surface formed on the upper side is oblique to the blade and has an arch shape that protrudes upward when viewed vertically from the blade, so that water that enters the front / back side of the blade tends to flow in an arc along the arch-shaped upper surface.

[0015] As a result, in the flow direction of water entering the front / rear sides of the blades, the water that has flowed over the upper surface of the bow moves diagonally downward on the downstream side of the upper surface of the bow, making it easier to push down the existing water. In this way, the water that has flowed over the upper surface of the bow pushes down the existing water, and as a result of this resistance (reaction force), it makes it easier to push the commutator and the blades vertically upward.

[0016] In addition, if the upper side of the most protruding point in the longitudinal section is a generally linear slope, the water that has passed over the most protruding point will easily flow along the generally linear slope of the upper surface, making it difficult for vortices (Karman vortices) to occur. This makes it difficult for the blade to encounter resistance from the water. Furthermore, when the blade is moved forward (feathered) so that it is roughly parallel to the water surface, water and air will collide with the linear slope of the upper surface, reducing water and air resistance and making it difficult for the boat to decelerate when moving forward.

[0017] As a means for solving the above-mentioned problems, the present invention provides an oar comprising a blade and a commutator fixed to the blade.

[0018] Such a configuration makes it easier to operate the oars. Effect of the Invention

[0019] According to the present invention, it is possible to provide a commutator and an oar equipped with a commutator that makes the oar easier to operate. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a plan view of a single scull and oar according to the present embodiment, showing the catch phase. [Diagram 2] FIG. 2 is a plan view of the single scull and oar of the present embodiment, showing the middle stage. [Diagram 3] FIG. 1 is a plan view of a single scull and oars according to an embodiment of the invention, showing the finishing phase. [Figure 4] FIG. 2 is a surface view (front view) of the blade according to the present embodiment, showing the catching stage. [Diagram 5] FIG. 2 is a surface view (front view) of the blade according to the present embodiment, showing the middle stage. [Figure 6] FIG. 2 is a surface view (front view) of the blade according to the present embodiment, showing the finishing stage. [Figure 7] FIG. 2 is a bottom view (rear view) of the blade according to the embodiment, showing the finishing stage. [Figure 8] FIG. 2 is a perspective view of a commutator according to the embodiment. [Figure 9] FIG. 2 is a plan view of the commutator according to the embodiment. [Figure 10] 5 is a cross-sectional view taken along line X1-X1 of FIG. 4. [Figure 11] 8 is a cross-sectional view taken along line X2-X2 of FIG. 7. [Figure 12] 1 is a graph showing the flow velocity of water on a surface side of a blade. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] An embodiment of the present invention will be described with reference to Figs. 1 to 12. Here, the oar 200 (scull oar) on the bow side of a racing single scull 300 (boat) will be described. The same applies to the stroke side. Facing the front of the single scull 300 in the traveling direction (upper side of the paper in Figs. 1 to 3), the left side is the stroke side and the right side is the bow side. The rower sits facing backwards on a seat 320, which will be described later.

[0022] <Single Scull> As shown in Figures 1 to 3, the single scull 300 comprises a single scull body 310, a seat 320, and a row lock 330 (oar support). The single scull body 310 is an elongated hull, and the cross section in the width direction is approximately semicircular. The seat 320 is provided so as to be slidable in the longitudinal direction (front-rear direction) of the single scull body 310.

[0023] The row lock 330 is rotatably attached to the tip of a rigger (not shown) that is provided to protrude from the left and right sides at approximately the middle position of the single scull body 310. The row lock 330 is a U-shaped member that supports the oar 200 from below. That is, the row lock 330 supports a sleeve 230 (described later) of the oar 200, and when the rower operates the oar 200, the row lock 330 becomes the point of action between the single scull 300 and the oar 200.

[0024] Oar The oar 200 includes an elongated cylindrical shaft 210, a blade 100 fixed to the tip of the shaft 210, a handle 220 fixed to the base end of the shaft 210, a sleeve 230 fitted onto the base end side of the shaft 210, three commutators 1 (see FIG. 4) fixed to the front surface 101 of the blade 100, and one commutator 2 (see FIG. 7) fixed to the back surface 102 of the blade 100. The commutators 1 and 2 have the same shape. Here, the axis of the oar 200 corresponds to the axis O2 of the shaft 210 (see FIG. 4).

[0025] The shaft 210 and the blade 100 are made of, for example, CFRP (Carbon Fiber Reinforced Plastic) and have appropriate elasticity. The handle 220 is a part that the rower grasps to operate the oar 200. The sleeve 230 is a cylindrical part that is supported by the row lock 330. When the rower grasps and operates the handle 220, the oar 200 rotates with the row lock 330 (sleeve 230) as a fulcrum.

[0026] <Blade> 4 to 7, the blade 100 is a member that paddles through water, and has a wide, thin plate shape extending in the direction of the axis O2 of the shaft 210. Here, the blade 100 according to this embodiment is asymmetric with respect to the axis O2 of the shaft 210. In other words, when the width direction of the blade 100 is the vertical direction (when the blade 100 is perpendicular to the water surface S1), the blade 100 is offset vertically downward so that the portion that paddles through water becomes larger.

[0027] <Commutator> The commutator 1 rectifies the flow of water on the front surface 101 of the blade 100, thereby stabilizing the movement of the blade 100. The commutator 2 rectifies the flow of water on the back surface 102 of the blade 100, thereby stabilizing the movement of the blade 100.

[0028] <Commutator - Surface side> 4 to 6 and 8 to 10, three commutators 1 fixed to protrude from the surface 101 of the blade 100 will be described. The commutators 1 are adhered to the surface 101 with, for example, an adhesive. The commutators 1 are elongated members made of resin and extending in the direction of the axis O3. The resin is, for example, a TPU (Thermoplastic Polyurethane) resin, an ABS (Acrylonitrile Butadiene Styrene) resin, or a PLA (Poly-Lactic Acid) resin.

[0029] The two commutators 1, 1 are disposed outside (tip side) the middle in the longitudinal direction of the blade 100 and in two stages in the width direction (height direction). One commutator 1 is disposed inside (base end side) the middle in the longitudinal direction of the blade 100 and between the two outer commutators 1, 1 in the width direction. When the blade 100 is perpendicular to the water surface S1, the width direction of the blade 100 becomes the height direction.

[0030] Each commutator 1 is fixed to the surface 101 in a state (posture) in which the tip side is inclined upward, that is, in a state in which the base end side is inclined downward, when the width direction of the blade 100 is the vertical direction. That is, when the shaft 210 enters the water at a predetermined angle θ1 (10 to 20°, preferably 15°) with respect to the water surface S1 (see FIG. 4), the width direction of the blade 100 is the vertical direction, and the blade 100 is disposed at a predetermined depth D1 (3 to 15 cm) below the water surface S1, the axis O3 of the commutator 1 is in a state in which the tip side (outside) is inclined upward with respect to the axis O2 of the shaft 210. The angle θ2 (see FIG. 8) between the axis O3 and the horizontal plane S2 is, for example, 10 to 20°.

[0031] In the vertical cross section, the commutator 1 is a substantially triangular shape with the surface side protruding (see FIG. 10). The vertical cross section is a cross section perpendicular to the axis O3. In the vertical cross section, the commutator 1 protrudes most downward from the middle. That is, the protruding portion 30 (top) of the commutator 1 is lower than the middle in the vertical direction (height direction, width direction). The surface of the protruding portion 30 is chamfered to have an "R-shape". The upper surface 11 on the upper side of the protruding portion 30 is a concave curved surface that is slightly recessed toward the blade 100 (surface 101), and water easily flows in a laminar flow at the boundary between the upper surface 11 and the surface 101, making it difficult for vortexes to occur. The lower surface 21 on the lower side of the protruding portion 30 is also a concave curved surface that is slightly recessed toward the blade 100 (surface 101). However, the upper surface 11 and the lower surface 21 may be configured as linear inclined surfaces.

[0032] The protruding length L1 of the protruding portion 30 is maximum at the center in the direction of the axis O3 (the longitudinal direction of the commutator 1) and gradually becomes shorter toward both outsides (see FIG. 9). The upper surface 11 formed on the upper side of the protruding portion 30 is inclined with respect to the surface 101 of the blade 100 (see FIG. 10), and has an upwardly protruding arch shape when viewed in the vertical direction of the blade 100 (when viewed in the vertical direction of the paper in FIG. 4). The upper edge 12 of the commutator 1 when viewed from the front (when viewed in the vertical direction of the blade 100) has an upwardly protruding arc shape (see FIG. 8). The lower edge 22 of the commutator 1 when viewed from the front has a slightly downwardly protruding arc shape (see FIG. 8).

[0033] The angle θ3 between the upper surface 11 and the surface 101 is, for example, 20 to 50° (preferably, 30 to 40°) (see FIG. 10). The angle θ4 between the lower surface 21 and the surface 101 is, for example, 50 to 70° (preferably, 55 to 65°). In other words, the upper surface 11 is gently inclined with respect to the surface 101, and the lower surface 21 is steeply inclined with respect to the surface 101.

[0034] <Commutator - back side> 7 and 11, a single commutator 2 that is fixed to protrude from the rear surface 102 of the blade 100 will be described. Regarding the commutator 2, differences from the commutator 1 will be described.

[0035] The commutator 2 is an elongated member extending in the direction of the axis O4. The commutator 2 is disposed inside (toward the base end) the middle of the blade 100 in the longitudinal direction, and at the upper stage in the width direction (height direction).

[0036] The commutator 2 is fixed to the back surface 102 in a state (posture) in which the tip side is inclined downward, that is, in a state in which the base end side is inclined upward, when the width direction of the blade 100 is the vertical direction. That is, when the shaft 210 enters the water at a predetermined angle θ1 (10 to 20°, preferably 15°) with respect to the water surface S1 (see FIG. 7), the width direction of the blade 100 is the vertical direction, and the blade 100 is disposed at a predetermined depth D1 below the water surface S1, the axis O2 of the shaft 210 and the axis O4 of the commutator 2 are approximately parallel, and the base end side (inner side) is inclined upward. The angle θ5 between the axis O4 and the horizontal plane S2 is, for example, 10 to 20° (preferably 15°).

[0037] In a vertical cross section, the commutator 2 is a generally triangular shape with a protruding back surface (see FIG. 11). A vertical cross section is a cross section perpendicular to the axis O4. In a vertical cross section, the commutator 1 protrudes most downward from the middle. In other words, the protruding portion 30 (top) of the commutator 2 is lower than the middle in the up-down direction (height direction, width direction). The surface of the protruding portion 30 is chamfered to have an "R-shape." An upper surface 11 on the upper side of the protruding portion 30 and a lower surface 21 on the lower side of the protruding portion 30 are generally linear.

[0038] The upper surface 11 formed on the upper side of the protruding portion 30 is inclined with respect to the rear surface 102 of the blade 100 (see FIG. 7), and has an arch shape that protrudes upward when viewed in the vertical direction of the blade 100 (viewed in a direction perpendicular to the paper surface of FIG. 7). The upper edge of the commutator 2 when viewed from the front (viewed in the vertical direction of the blade 100) has an arc shape that protrudes upward (see FIG. 7). The lower edge of the commutator 2 when viewed from the front (viewed in the vertical direction of the blade 100) has an arc shape that protrudes slightly downward (see FIG. 7).

[0039] <Effects of commutators and oars> Next, the effects of the commutator 1, the commutator 2, and the oar 200 will be described. When a rower sits on the seat 320, grips the handle 220, and operates the oar 200, the single scull 300 moves forward along a linear target line O1 (see Figs. 1 to 3). Specifically, the single scull 300 moves forward by repeating a catch stage (see Figs. 1 and 4), a middle stage (see Figs. 2 and 5), a finish stage (see Figs. 3, 6, and 7), and a forward stage.

[0040] <Catch stage> The catch stage is when the rower bends his legs in a forward leaning position and moves the seat 320 backward (Fig. 1), then raises the handle 220 to lower the blade 100 into the water and catch the water with the blade 100. When the rower then straightens his legs while still leaning forward and pulls the handle 220, the single scull 300 moves forward along the target line O1 with the position where the blade 100 caught the water as the fulcrum and the row lock 330 as the point of action (see arrow A1 in Fig. 1). In other words, the oar 200 rotates with the position where the blade 100 caught the water as a substantially fixed point, causing the single scull 300 to move forward.

[0041] Here, since the length of the oar 200 is constant, as the single scull 300 advances, the blade 100 is pushed further outward (toward the bow side) in the water (see arrow A11 in FIG. 1). Then, water flows from the outside to the inside on the front surface 101 and the back surface 102 of the blade 100 (see arrow A21 in FIG. 4 and FIG. 8).

[0042] Then, the water flowing from the outside to the inside hits the inclined lower surface 21 of the commutator 1, generating a force that pushes the commutator 1 and the blades 100 vertically upward (see arrow A22 in Figs. 4 and 8). In this way, a force is generated that pushes the commutator 1 and the blades 100 vertically upward immediately after catching, making it difficult for the blades 100 to sink and making it easier to operate the oar 200.

[0043] As the stage progresses from the catch stage, the water flow velocity on the front surface 101 and the back surface 102 of the blade 100 gradually decreases (see FIG. 12). In FIG. 12, the water flow velocity toward the inside of the front surface 101 of the blade 100 is negative, and the water flow velocity toward the outside of the front surface 101 of the blade 100 is positive.

[0044] Some of the water flows over the protrusions 30 of the commutator 1 and into the upper surface 11 (see arrow A23 in Figs. 4 and 8). At this time, since the upper surface 11 is a gentle linear slope, the water that has flowed over flows in a laminar flow along the upper surface 11. Since the water that has flowed over flows in a laminar flow (see arrow A23 in Fig. 10), water vortices are less likely to be generated, and the blade 100 can move more easily without being resisted by vortices. Here, the upper surface 11 may be configured to have a plurality of grooves / ribs formed, for example, along the inclination direction, to make it easier for the water that has flowed over the protrusions 30 to flow in a laminar flow.

[0045] Furthermore, the water flowing from the outside to the inside flows in an arc along the bow-shaped upper surface 11 (see arrow A24 in Figs. 4 and 8). Then, in the flow direction of the water flowing in this arc, on the downstream side of the bow-shaped upper surface 11, the water that has flowed over the bow-shaped upper surface 11 flows diagonally downward and pushes down the existing water.

[0046] In this way, the water that has flowed along the arch-shaped upper surface 11 pushes down the existing water, and as a resistance (reaction) to this, the commutator 1 and the blade 100 are pushed up vertically upward. In other words, immediately after catching, a lift force that pushes the commutator 1 and the blade 100 vertically upward is generated, making it difficult for the blade 100 to sink and making it easier to operate the oar 200. The same is true for the back surface 102 side of the blade 100, where the water that has flowed along the arch-shaped upper surface 11 of the commutator 2 pushes down the existing water, and as a resistance (reaction) to this, the commutator 1 and the blade 100 are pushed up vertically upward.

[0047] <Middle stage> The middle stage is when the single scull 300 advances and the angle between the single scull 300 and the oar 200 becomes 90° (see Figs. 2 and 5). In the middle stage, the water flow velocity on the front surface 101 and the back surface 102 of the blade 100 becomes approximately 0 (see Fig. 12).

[0048] Thereafter, when the rower leans his torso back and pulls the handle 220, the single scull 300 moves further forward along the target line O1 with the blade 100 catching the water as the fulcrum and the row lock 330 as the point of action (see arrow A2 in FIG. 2).

[0049] Here, since the length of the oar 200 is constant, as the single scull 300 advances from the middle stage, the blade 100 is gradually pulled inward (toward the single scull 300) in the water (see arrow A12 in FIG. 2). As a result, water flows from the inside to the outside on the front surface 101 and back surface 102 of the blade 100 (see arrow A31 in FIG. 6). Note that as the blade advances from the middle stage, the flow velocity of the water on the front surface 101 and back surface 102 of the blade 100 gradually increases (see FIG. 12).

[0050] <Finishing stage> The finish stage is a stage in which the rower leans his or her upper body back, bends his or her arms, pulls the handle 220 all the way back, and then lowers the handle 220 to raise the blade 100 and pull it out of the water.

[0051] Here, in the fish stage, water moving from inside to outside on the surface 101 of the blade 100 collides with the inclined upper surface 11 of the commutator 1, generating a force that pushes the commutator 1 and the blade 100 vertically downward (see arrow A32 in FIG. 6). In this way, in the finish stage, a force that pushes the blade 100 vertically downward is generated, making it difficult for the blade 100 to rise above the water early and making it easier for the blade 100 to push the water to the end.

[0052] Moreover, the water flowing from the inside to the outside flows in an arc along the bow-shaped upper surface 11 (see arrow A34 in FIG. 6). Then, in the flow direction of the water flowing in this arc, on the downstream side of the bow-shaped upper surface 11, the water that has flowed over the bow-shaped upper surface 11 flows diagonally downward, pushing down the existing water.

[0053] In this way, the water that has flowed along the arched upper surface 11 pushes down the existing water, and as a resistance (reaction) to this, the commutator 1 and the blade 100 are pushed up vertically upward. That is, in the fish stage, a lift force that pushes up the commutator 1 and the blade 100 vertically upward is generated, making it difficult for the blade 100 to sink, and making it easier to operate the oar 200. The same is true for the back surface 102 side of the blade 100, where the water that has flowed along the arched upper surface 11 of the commutator 2 (see arrow A44 in FIG. 7) pushes down the existing water, and as a resistance (reaction) to this, the commutator 2 and the blade 100 are pushed up vertically upward.

[0054] Furthermore, if the operation of the oar 200 is delayed relative to the boat speed of the single scull 300, the water will push the underside 102 of the blade 100 backward. That is, the water flowing outward on the underside 102 of the blade 100 (see arrow A41 in FIG. 7) collides with the inclined lower surface 21 of the commutator 2, generating a force that pushes the commutator 2 and the blade 100 vertically upward (see arrow A42 in FIG. 7). Since a force is generated that pushes the blade 100 vertically upward, it becomes easier for the blade 100 to come out of the water, making it difficult to perform a so-called harakiri (a slashing motion), and it becomes easier to operate the oar 200.

[0055] Some of the water climbs over the protruding portion 30 of the commutator 2 and flows into the upper surface 11 (see arrow A43 in FIG. 11). At this time, since the upper surface 11 is a gentle linearly inclined surface, the water that climbs over flows in a laminar flow along the upper surface 11. In this way, the water that climbs over flows in a laminar flow (see arrow A43 in FIG. 11), making it difficult for water vortices to occur, and therefore the blade 100 can move more easily without receiving resistance from vortices.

[0056] <Forward Phase> The forward phase is when the rower leans his / her upper body forward, bends his / her legs, and then moves forward to the next catch with the handle 220 and seat 320. In the forward phase, to reduce the air resistance experienced by the blade 100, the handle 220 is rotated approximately 90° so that the front surface 101 faces vertically upward. That is, in the forward phase, the blade 100 moves in an arc so as to move forward in the direction of travel, with the back surface 102 facing the water surface S1 (vertically downward).

[0057] Here, in the forward stage, the front side of the commutator 2 fixed to the back surface 102 on the vertically lower side of the blade 100 forms a gently sloping upper surface 11, so that even if the blade 100 collides with the water surface S1 because, for example, the water surface S1 is rough, the upper surface 11, which is the main collision surface, is a gently sloping surface, so that the water easily passes through the commutator 2 (see arrow A51 in FIG. 11), reducing the impact on the blade 100. Because the impact on the blade 100 is reduced in this way, the oar 200 becomes easier to operate.

[0058] <<Variations>> Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment and may be modified, for example, as follows.

[0059] In the above-described embodiment, the commutator 1 and the commutator 2 are separate components from the blade 100 and are bonded with an adhesive. However, for example, the commutator 1 and / or the commutator 2 may be made of CFRP (Carbon Fiber Reinforced Plastic) and may be integrally molded with the blade 100.

[0060] In the above embodiment, a configuration in which three commutators 1 are fixed to the front surface 101 of the blade 100 has been exemplified, but the number of commutators 1 is not limited to this. Also, a configuration in which two commutators 1 are arranged in two stages on the tip side and one commutator 1 is arranged on the base end side on the front surface 101 of the blade 100 has been exemplified, but the arrangement of the commutators 1 can be freely changed. The same applies to the commutator 2 on the back surface 102 of the blade 100.

[0061] In the above-described embodiment, a configuration in which the upper surface 11 and the lower surface 21 of the commutator 1 and the commutator 2 are linearly inclined surfaces in a longitudinal cross section has been exemplified, but other configurations, for example, a convex curved surface or a concave curved surface may also be used.

[0062] In the above embodiment, the commutator 1 and the commutator 2 are configured to protrude most downwardly from the middle in the vertical cross section. However, they may be configured to protrude most upwardly from the middle, for example.

[0063] In the above embodiment, the present invention is applied to the oar (scull oar) on the bow side of a single scull (boat), but the present invention may also be applied to, for example, the oar on the stroke side of a single scull (boat). Also, the present invention may be applied to the scull oar and sweep oar of a crew boat (double scull, quadruple, coxed four, eight, etc.). [Explanation of symbols]

[0064] 1, 2 commutator 11 Top side 21 Bottom side 30 Protrusion 100 Blades 101 Surface 102 Back side 200 All

Claims

1. A long and narrow rectifier that is fixed to the blade of an oar and rectifies the flow of water, The blade extends in an axial direction of the oar and has a longitudinal direction and a width direction perpendicular to the longitudinal direction. The blade protrudes from the surface that grabs the water, and the tip side, which is the outer side in the longitudinal direction when the width direction is the vertical direction, is fixed at an upward incline, In a vertical cross section, which is a cross section in the vertical direction when the width direction is the vertical direction, the protrusion is most protruding below the middle. A commutator comprising:

2. A long and narrow rectifier that is fixed to the blade of an oar and rectifies the flow of water, The blade extends in an axial direction of the oar and has a longitudinal direction and a width direction perpendicular to the longitudinal direction. The blade protrudes from the back surface opposite to the surface that grabs water, and the tip side, which is the outer side in the longitudinal direction when the width direction is the vertical direction, is fixed at a downward incline, In a vertical cross section, which is a cross section in the vertical direction when the width direction is the vertical direction, the protrusion is most protruding below the middle. A commutator comprising:

3. A commutator according to claim 1 or claim 2, In the longitudinal direction of the commutator, the protruding length from the blade is maximum at the middle and gradually becomes shorter toward both outer sides, The upper surface formed on the upper side is inclined with respect to the blade and has an arch shape protruding upward when viewed in the vertical direction of the blade. A commutator comprising:

4. Blade and A commutator according to claim 1 or 2 fixed to the blade; Equipped An oar characterized by:

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