阅读说明：本技术 球拍 (Racket ) 是由 川端雅人 塙亮一 加藤仁 藤中涉 长泽康史 于 2018-05-18 设计创作，主要内容包括：本发明能够延长击球时球与拍线的接触时间。球拍(10)具有拍线被张紧而形成击球面的拍框(15)和形成于拍框和拍柄(12)之间的拍杆(13)。在拍框和拍杆之间形成接合它们的接合部(24)。形成由拍框和拍杆包围的开口(25),邻接开口的区域为开口形成区域(26)。在接合部上形成用于插通拍线的孔(17),在离开孔和开口形成区域的位置且在夹持厚度方向中心位置的两侧上分别形成有凹部(30)。(The invention can prolong the contact time of the ball and the line when the ball is hit. The racket (10) has a frame (15) with a string stretched to form a striking surface and a shaft (13) formed between the frame and a handle (12). A joint (24) for joining the frame and the shaft is formed between the frame and the shaft. An opening (25) surrounded by the frame and the shaft is formed, and a region adjacent to the opening is an opening forming region (26). A hole (17) for inserting the beat line is formed in the joint portion, and recesses (30) are formed in positions away from the hole and the opening forming region and on both sides of the center position in the thickness direction.)

1. A racket, comprising:

a racket frame, wherein the racket line is tensioned to form a ball striking surface; and

a racket rod formed between the racket frame and the racket handle,

wherein a joint part joining the frame and the shaft is formed between the frame and the shaft,

forming an opening surrounded by the frame and the shaft, an area adjacent to the opening being an opening forming area,

the joint portion is formed with a hole for inserting the racket string therethrough, and a recess is formed at a position apart from the hole and the opening forming region on each of both sides sandwiching a center position in a thickness direction.

2. The racket of claim 1,

the racket shaft has a neck that branches off into two strands from the handle toward the head, and the engaging portion and the recessed portion extend in the extending direction of the neck.

3. The racket of claim 2,

the joint portion has a pair of inclined surfaces gradually approaching from both sides in the thickness direction to the outside when viewed in a cross section perpendicular to the extending direction of the neck,

the concave portions are formed on the pair of inclined surfaces, respectively.

4. Racket according to claim 2 or 3,

the width in the direction perpendicular to the extending direction of the recess is formed to be gradually larger from both ends in the extending direction toward the center.

5. Racket according to any of the claims 1 to 4,

a groove portion having the hole on the bottom side is formed on the outer peripheral side of the frame and the joint portion,

the groove is formed continuously in the frame and the joint, and the groove formed in the joint has a depth greater than that of the groove formed in the frame.

Technical Field

The present invention relates to a racket, in particular, a racket for soft tennis.

Background

In racket sports such as tennis, a player strikes a ball by swinging a racket to play a game. The racket has a handle to be held by a player, a shaft provided at one end of the handle, and a frame formed in a ring shape and provided at the other end of the shaft. A racket string is stretched in a lattice shape on the inner side of the racket frame, and a hitting surface for hitting a ball is formed by such a racket string (see, for example, patent document 1).

Disclosure of Invention

Problems to be solved by the invention

Recently, due to the increase in the swing speed of a racket and the increase in the hitting speed of a ball, the contact time between the ball and a racket string at the time of hitting the ball is shortened. Therefore, the so-called ball holding performance (ball holding feeling) is lowered, and the ball control of the player at the time of hitting the ball tends to be difficult.

Therefore, in order to extend the contact time between the ball and the racket string, it is considered to increase the pitch of the racket string and reduce the tension of the racket string. In this case, the contact time between the ball and the line can be extended by reducing the face pressure of the hitting surface formed by the line, but there is a problem that the player feels the feeling of hitting blurred, and eventually the controllability cannot be sufficiently improved.

As another structure for extending the contact time, a structure is also conceivable in which the rigidity of the frame and the shaft is reduced to significantly improve the flexibility of the racket. However, in this case, it takes time for the bent racket to return to the original shape. Therefore, even if the player tries to hit the ball in a desired hitting direction, the ball is hit in a direction deviating from the desired hitting direction, and there is a problem that the ball control performance cannot be sufficiently improved.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a racket which can extend the contact time between a ball and a racket string at the time of a ball impact and can improve the ball control of the ball impact.

Means for solving the problems

The racket of the present invention includes a frame having a racket string stretched to form a ball striking surface, and a shaft formed between the frame and a handle, wherein a joint portion for joining the frame and the shaft is formed between the frame and the shaft, an opening surrounded by the frame and the shaft is formed, a region adjacent to the opening is an opening forming region, a hole for inserting the racket string is formed in the joint portion, and recesses are formed in positions away from the hole and the opening forming region and on both sides of a center position in a thickness direction.

According to this configuration, since the concave portion is formed in the joint portion that joins the frame and the shaft, the rigidity of the joint portion can be reduced, and the joint portion can be easily deformed at the time of hitting a ball. Thus, the frame is easily deformed so as to be twisted with respect to the shaft, and the contact time between the ball and the racket string can be extended, and the ball holding performance can be improved to improve the ball control performance. Further, only the rigidity of the joint portion can be reduced as compared with the conventional structure in which the recess portion is not formed, in other words, the rigidity of the frame and the racket shaft can be maintained as compared with the conventional structure. This can prevent the bending deformation amount of the frame and the shaft from changing during hitting, and can prevent the reduction of the ball control performance.

Further, in the racket of the present invention, it is preferable that the shaft has a neck bifurcated from the handle toward the head, and the engaging portion and the recessed portion extend in an extending direction of the neck. According to this configuration, the recess can be formed over a wide range of the joint portion, and the rigidity of the joint portion can be further reduced.

In the racket according to the present invention, it is preferable that the joint portion has a pair of inclined surfaces gradually approaching outward from both sides in the thickness direction when viewed in a cross section perpendicular to the extending direction of the neck, and the concave portions are formed on the pair of inclined surfaces, respectively. According to this configuration, since the joint portion forms the inclined surface, the cross-sectional shape of the joint portion is approximated to a triangular shape having the inclined surfaces as oblique sides. This makes it possible to achieve a better reduction in the rigidity of the joint portion, and to achieve the above-described function.

In the racket of the present invention, it is preferable that the width in a direction perpendicular to the extending direction of the concave portion is formed to be gradually larger from both ends of the extending direction toward the center. According to this configuration, the rigidity of the joint portion can be adjusted according to the width of the recess portion in the extending direction of the joint portion by changing the width of the recess portion. Further, the following visual effects can be obtained: the maximum reduction in rigidity can be achieved in the central portion where the width of the recess is the largest.

In the racket of the present invention, it is preferable that a groove having the hole at a bottom side is formed on an outer peripheral side of the frame and the joint portion, the groove is continuously formed on the frame and the joint portion, and a groove depth of the groove formed in the joint portion is larger than a groove depth of the groove formed in the frame. According to this configuration, not only the rigidity of the joint portion can be reduced by the recess portion, but also the rigidity of the joint portion can be reduced by the shape of the groove portion.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, since the concave portion is formed in the joint portion that joins the frame and the paddle shaft, the contact time between the ball and the line at the time of hitting the ball can be extended, and the ball control performance of the hit ball can be improved.

Drawings

Fig. 1 is an external view of a state in which the racket of the embodiment is used, fig. 1A is a front view of the racket, and fig. 1B is a side view of the racket.

Fig. 2 is a partial schematic perspective view of the racket.

Fig. 3 is a cross-sectional view taken along line a-a of fig. 1A.

Fig. 4 is an explanatory view of a deforming action of the racket at the time of hitting a ball.

Fig. 5 is a graph showing the rate of change of the frame angle at the time of impact.

FIG. 6 is a schematic cross-sectional view of the joint of examples 1 to 3 and comparative examples 1 to 4.

Detailed Description

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, although an example in which the present invention is applied to a racket for soft tennis will be described below, the application object is not limited thereto, and may be modified. For example, a tennis racket for a hard tennis ball, a racket for a squash ball, or the like can be applied.

Fig. 1 is an external view of a state in which the racket of the embodiment is used, fig. 1A is a front view of the racket, and fig. 1B is a side view of the racket. In the following drawings, a part of the structure is omitted for convenience of explanation.

As shown in fig. 1, the racket 10 has a head 11, which is a portion for hitting a ball, a grip 12, which is a portion for a player to hold the racket 10, and a shaft 13 formed between the head 11 and the grip 12. In the following description, as indicated by arrows in fig. 1, the side of the racket 10 in the longitudinal direction where the head 11 is located is defined as the upper side, and the side where the handle 12 is located is defined as the lower side. In addition, on the striking surface of the racket 10 (i.e., on a plane along the striking surface), a direction perpendicular to the longitudinal direction is taken as a width direction (or a left-right direction), and a direction perpendicular to the striking surface of the racket 10 is taken as a thickness direction (or a front-back direction).

The head 11 has a frame 15 having a vertically long oval ring shape, and a hitting surface (face) is formed on the inside of the frame 15 by stretching a racket string (not shown) in a lattice shape. The outer peripheral surface 15a of the frame 15 is provided with a groove portion 16 depressed at the center in the thickness direction. The groove portions 16 are continuously provided in the circumferential direction of the racket frame 15. The frame 15 is provided with a plurality of holes 17 for inserting strings. The plurality of holes 17 are formed to penetrate from the bottom side of the groove portion 16 on the outer peripheral surface 15a of the frame 15 to the inner peripheral surface 15 b. A plurality of holes 17 are provided along the circumferential direction of the racket frame 15.

In the frame 15, the position where the left-right width is largest is formed above the center position in the vertical direction. This makes it possible to set a so-called sweet spot above the center position of the frame 15 in the vertical direction.

The shaft 13 has a neck 20 that branches off in two from the handle 12 toward the head 11 when viewed from the front-rear direction, and a shoulder 18 is formed between the left and right necks 20 and forms a part of the frame 15. The head 20 has a circular arc-shaped curved shape between the handle 12 and the head 11.

Therefore, a joint portion 24 for joining the upper end of the neck 20 and the lower left and right sides of the frame 15 (left and right sides of the shoulder 18) is integrally formed. The joint portion 24 is formed so as to overlap with the formation position of the frame 15 in the vertical direction, and is formed so as to bulge the lower portion of the frame 15 to the outside. Further, the joint portion 24 is provided in a shape extending in the extending direction of the curved neck 20. Further, the engaging portions 24 are provided on both end sides in the extending direction of the paddle shoulder 18. The groove 16 formed in the frame 15 is also continuously formed in the joint 24, and a hole 17 for inserting a racket string is also formed through the groove 16.

An opening 25 is formed in the front-rear direction so as to be surrounded by a shoulder 18 of the frame 15 and left and right neck portions 20 of the shaft 13. Therefore, as shown in fig. 2, the region adjacent to the opening 25 is an opening forming region 26. Fig. 2 is a partial schematic perspective view of the racket. The opening forming region 26 has an opening inner peripheral surface 27 extending in the front-rear (thickness) direction on the side of the left and right neck portions 20, the shoulder portions 18, and the opening 25 of the joint portion 24; and an opening abutting surface 28 which is connected to the opening inner peripheral surface 27 and is located closer to the opening 25 side than the maximum front-rear width forming position 29 of the neck portion 20 and the joint portion 24. The opening abutting surface 28 has a front-rear width smaller than the front-rear width of the maximum front-rear width forming position 29, and is formed so as to be recessed from the maximum front-rear width forming position 29.

The frame 15, the shaft 13, and the joint 24 are formed in a hollow cylindrical shape made of, for example, a fiber-reinforced resin, but may be formed in a non-hollow shape with a foam material filled therein, or made of wood or metal.

The left and right joint portions 24 are formed with recesses 30, respectively. The left and right engaging portions 24 and the recessed portion 30 have the same configuration except that the positions and directions are bilaterally symmetrical. Therefore, in the following description, specific configurations of the left-side joint portion 24 and the recess 30 will be described, and the description of the right-side joint portion 24 and the recess 30 will be simplified or omitted.

Fig. 3 is a cross-sectional view taken along line a-a of fig. 1A. As shown in fig. 3, the joint portion 24 has a pair of inclined surfaces 24a on both sides in the thickness direction. When viewed in cross section in fig. 3 (cross section perpendicular to the extending direction of the head unit 20), the pair of inclined surfaces 24a are formed so as to approach outward (to the left in fig. 3) from both sides in the front-rear (thickness) direction. More specifically, the front-rear inclined surfaces 24a are formed as surfaces inclined so as to approach each other from the maximum front-rear width forming positions 29 toward the front and rear ends of the groove portion 16 in the inner-outer direction of the engagement portion 24.

The front and rear inclined surfaces 24a are formed with recesses 30 (rear recesses are not shown in fig. 2). The recessed portion 30 is formed at a symmetrical position and shape at the front-rear (thickness) direction center position C of the front-rear inclined surface 24a with the joining portion 24 therebetween. The recess 30 is formed so as to be retracted without protruding from the inclined surface 24a, in other words, at a position separated from the groove 16, the hole 17, and the opening forming region 26.

As shown in fig. 2, the outer peripheral edge of the concave portion 30 is formed in an elongated shape extending in the extending direction of the neck 20, and is formed so that the width in the direction perpendicular to the extending direction changes. Specifically, the width is formed so as to gradually increase from both ends in the extending direction toward the center, and further formed so as to form a triangular shape. The apex of the triangular shape of the concave portion 30 is formed on both sides in the extending direction of the neck 20 and on the inner side of the middle portion in the extending direction.

Next, a description will be given of a deforming operation of the racket at the time of hitting a ball, with reference to fig. 4. Fig. 4A to 4C are explanatory views of the deforming action of the racket at the time of hitting a ball. As shown in fig. 4A, for example, in a Ground stroke (hitting course) of a tennis ball, when a tapping spin is applied to the ball B, the ball B is hit in the vertical direction in the figure with the width direction of the frame 15. In this striking, the racket 10 is often moved from the lower side to the upper side in order to impart a tapping rotation during the swing. At this time, the hitting position of the ball B tends to be upward in fig. 4A of the face F in order to make an area of the face F to be rolled and rubbed against the ball B. Further, the hitting surface F tends to be tilted from above so as to wrap the ball B flying in order to impart the driving rotation.

Then, as shown in fig. 4B, when the ball B hits the hitting surface F, the frame 15 is elastically deformed in a twisted manner in the direction of the arrow R1 by the impact force generated at this time. Then, the elastic deformation is restored, and as shown in fig. 4C, the racket frame 15 is rotationally restored in the direction of arrow R2 in the figure. The restoration of the twist in the direction of the arrow R2 acts to impart a driving rotation to the ball B contacting the ball striking surface F.

In the present embodiment, the formation of the recessed portion 30 can reduce only the rigidity of the joint portion 24, as compared with a racket of a conventional structure in which the recessed portion 30 is not formed. This makes it possible to easily generate the deformation of the racket 10 shown in fig. 4. Specifically, by the reduction in rigidity of the joint portion 24, the amount of torsional deformation in the arrow R1 direction of fig. 4B can be increased, and the amount of recovery in the arrow R2 direction of fig. 4C can also be increased.

With such a deformation, even a skilled person who swipes at a high speed can extend the contact time between the ball B and the face F, and the ball holding performance (feeling of holding) can be improved. As a result, the time for the player to operate the hitting direction at the time of hitting the ball can be won, and the range of the hitting direction can be widened to allow the player to hit the ball at a large angle.

Further, since the torsional deformation amount and the recovery amount thereof become large, more driving rotation can be applied to the ball B, and the driving performance on the racket 10 can be improved. Further, the torsional deformation increases, so that the hitting surface F at the time of maximum torsion can be made to face upward, and the trajectory of the hit ball can be made to face upward, thereby improving the flight performance.

Further, by providing only the recessed portion 30 in the joint portion 24, even if the joint portion 24 is easily deformed when a hitting force is applied to the hitting surface F, the rigidity of the frame 15 and the shaft 13 itself can be maintained, and a drop in the rebound performance at the time of hitting can be prevented. Further, the deformation of the frame 15 and the shaft 13 itself can be made unchanged from the conventional structure, and the bending direction and the bending amount can be set to be the same as those of the conventional structure, thereby avoiding the deterioration of the ball control performance due to the change in bending. For example, when a ball is hit in a straight direction, the ball can be prevented from being hit in a direction deviating from the straight direction, and the ball control performance can be maintained well.

Therefore, the above description has been made of the case where the hitting position of the ball B is above the hitting surface F in fig. 4A, and the case where the hitting position is below the hitting surface F in the same figure has been tested. In this experiment, a ball was hit by a robot having high racket reproducibility as a player swings a racket, and the hitting surface and the ball at the time of hitting the ball were measured by a high-speed camera (5,000 Hz). The number of ball revolutions and the motion of the racket were evaluated by this measurement. The racket formed in the same manner as the above-described embodiment and the racket having the conventional structure without the recessed portion 30 formed therein are used.

Comparing the number of ball revolutions of the racket of the embodiment with that of the racket of the conventional structure, the number of ball revolutions of the embodiment is increased by about 27% compared to that of the ball of the conventional structure. Further, the motion of the racket is a graph as shown in fig. 5. Fig. 5 shows a graph of the rate of change of the frame angle at the time of impact. In the graph of fig. 5, the circle scale and the solid line represent the embodiment, and the triangle scale and the broken line represent the existing structure. As can be understood from the graph of fig. 5, the torsion of the embodiment is larger than that of the conventional structure, and the time for which the torsion occurs becomes longer. It is presumed that the direction of the twist is inclined toward the underlying layer of the frame (the striking face), and in this state, the driving rotation becomes easy by swinging the frame upward.

Next, in order to evaluate the difference in rigidity due to the shapes of the joining portions and the recessed portions according to the above-described embodiments, the rigidity in the shapes of examples 1 to 3 and comparative examples 1 to 4 shown in fig. 6 was calculated and compared. FIG. 6 is a schematic cross-sectional view of the joint parts of examples 1 to 3 and comparative examples 1 to 4. In fig. 6, the joint portion 24 is viewed in cross section at the same position as in fig. 3. In fig. 6, in all the examples and comparative examples, the frame 15 adjacent to the joint portion 24 was omitted, and calculation and comparison were made regarding the rigidity in the case of the solid structure.

In examples 1 to 3, the joint 24 was formed in the shape of the pair of inclined surfaces 24a and the groove 16 as in the above-described embodiment, and the thickness t of the joint 24 was set to about 13.5mm and the front-rear width h was set to about 19 mm. In examples 1 to 3, the depth d of the groove 16 was varied, and the depth d in example 1 was set to 2.5mm, the depth d in example 2 was set to 3mm, and the depth in example 3 was set to 5 mm. The joint 124 of comparative example 1 has substantially parallel regions on the front surface 124b and the rear surface 124c, compared to the shape of example 1, and the formation of the recess 30 of example 1 is omitted. The joining portions 124 of comparative examples 2 to 4 were formed into the same inclined surfaces 124a as the inclined surfaces 24a of examples 1 to 3, but the shape of the recess 30 was omitted. The depth d of the grooves 16 was 2.5mm in comparative examples 1 and 2, 3mm in comparative example 3, and 5mm in comparative example 4.

When 100 is taken as the value of the section rigidity of comparative example 1, table 1 below shows the relative values of the section rigidity (the second moment of the section with respect to the axis extending in the left-right direction) of examples 1 to 3 and comparative examples 2 to 4.

[ Table 1]

As can be understood from the results in table 1, the rigidity of the joint portions 24 and 124 can be reduced by 10% or more in examples 1 to 3 in which the concave portion 30 is formed, as compared with comparative examples 2 to 4. Thus, by forming the concave portion 30, the amount of torsional deformation shown in fig. 4 can be increased, and the contact time between the ball striking surface and the ball at the time of hitting the ball can be extended to improve the ball control performance. Further, since the amount of recovery of the torsional deformation is also increased, the ball can be greatly rubbed on the hitting surface, and the driving rotation performance can be improved.

In comparison between comparative example 1 and comparative examples 2 to 4, it is understood that the inclined surface 124a is formed on the joint portion 124, which contributes to a reduction in rigidity of the joint portion 124. Therefore, in the joint portion 24 of the embodiment, since the joint portion 24 has the shape of the inclined surface 24a, the sectional rigidity is reduced and the torsional deformation can be ensured to be increased.

In addition, in examples 1 to 3 and comparative examples 2 to 4, the depth of the groove 16 was small, but the value of the section rigidity was small. Thus, for example, the groove depth of the groove portion 16 formed in the joint portion 24 is larger than that of the groove portion 16 formed in the frame 15, so that the value of the cross-sectional rigidity of the joint portion 24 can be reduced and the distortion can be easily caused.

The present invention is not limited to the above-described embodiments, and can be implemented in various modifications. In the above-described embodiments, the size, shape, orientation, and the like shown in the drawings are not limited thereto, and may be appropriately modified within the range in which the advantageous effects of the present invention are exhibited. The present invention can be implemented with appropriate modifications without departing from the scope of the object of the present invention.

For example, the shape of the engaging portion 24 is not limited to the shape in the above embodiment. As an example, the shape of the joint portion 124 in comparative example 1 of fig. 5 may be adopted, and the concave portions 30 may be formed on both the front and rear surfaces of the joint portion 124. Among these, the formation of the recess 30 on the inclined surface 24a of the joint portion 24 according to the above embodiment is advantageous in that the recess is easily distorted by a reduction in the sectional rigidity, and the above-described effects can be more effectively obtained.

The shape of the recess 30 may be variously changed, and for example, the shape may be a rectangle or an ellipse extending in the extending direction of the joint portion 124, or may be formed by dividing one inclined surface 24a into a plurality of parts.

Industrial applicability of the invention

The present invention provides a racket having an effect of extending a contact time between a ball and a racket string at a time of hitting a ball.

The application is based on Japanese special application 2017-107782 applied on 31.5.2017. The contents of which are all incorporated herein.