JP3267901B2 - Hitting tool holder of hitting tool test hitting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holding device for holding a hitting portion of a hitting device (so-called grip portion) in a test device for hitting a hitting device such as a tennis racket. This makes it possible to hold the grip closer to the gripped state.

[0002]

2. Description of the Related Art Conventionally, various studies have been made on a test hitting device for a hitting tool such as a tennis racket so as to approach a state where a person is actually hitting a ball.

For example, as a conventional tennis racket test hitting device, the Japan Society of Mechanical Engineers [No. 940-9] Proceedings of the AVD Symposium P128, The Japan Society of Mechanical Engineers [No.
95-28] The 4th Symposium on Motion and Vibration Control Symposium P170, The Japan Society of Mechanical Engineers [No. 95-1
7] Proc. Of Robotics Mechatronics Conference '95 (Vol.B) P1260, The Japan Society of Mechanical Engineers [No. 96-
20] Symposium Proceedings, P35, Nikkei Mechanical 1995.5.515 no. 454 P66 and the like.

[0004] In the tennis racket test hitting apparatus reported in the above-mentioned document, a holding tool (gripper) 10 for holding a grip portion of the tennis racket is usually made by dividing a metal cylinder into half as shown in FIG. Two fixtures 1a, 1b
A rubber sheet 2 for absorbing impact is disposed on the inner peripheral surface of the tennis racket 20. The grip portion 21 of the tennis racket 20 is sandwiched between the fixtures 1a and 1b via the rubber sheet 2, and the fixtures 1a,
The racket 20 is held by tightening the screw 1b with the screw 3.

[0005] These test hitting devices have been developed to measure the mechanical properties of a racket during tennis volleying. For example, to reproduce the movement of a human hand when a human volleys, for example, a human The arm of the robot corresponding to the arm is controlled by motor control so that the racket (face face) is pulled toward the user immediately after hitting the ball, and FIG. 11 (A)
As shown in (B), the holder 10 is attached to the tip of the support rod 32 connected to the rotating shaft 31 to form a pendulum structure, and immediately after the ball is hit, the (racquet) face retreats in the direction in which the ball has advanced. Like that.

[0006]

By the way, in the above-mentioned conventional test hitting apparatus, when a repeated hit test is performed, the racket may be broken at a shaft portion or a throat portion. Thus, the support rod 32 supporting the holder 10 was made to be an elastic body to improve the shock absorption. However, when a repeated hit test was performed, the racket was broken at the shaft portion or the throat portion. On the other hand, even if a person volleys repeatedly, the racket does not usually break at the shaft portion or the throat portion. Even if the racket is broken, a part of the broken part is on a gutted face surface where the ball actually hits. It should be noted that there is also a disadvantage that the cost of the apparatus is increased whether the control is performed by the motor control or the pendulum structure.

[0007] From this, the present inventor believes that the distortion applied to the racket is different between when volleying with the above-described conventional hitting device and when a person actually volleys, and when the person actually volleys with the above-mentioned volley. The strain applied to the racket when volleyed by the test hitting device was measured.

FIG. 12 shows a tennis racket (DUNN)
According to PRO2000RIMSL3 manufactured by LOP, 30
It is a time waveform of the distortion added to the racket (shaft, throat, face at 4 o'clock) when a tennis ball having a speed of m / sec is volleyed. On the other hand, in FIG. 13, as shown in FIGS. 14A and 14B, a rotary plate (turntable) 302 having a diameter of 120 mm is attached to a shaft portion 301 that protrudes horizontally from the support frame 300. ) 302 is fixed at the center with a holder 10 (a metal cylinder having an overall length of 70 mm and an inner diameter of 50 mm is halved and sorbosein rubber (manufactured by Sanshin Kosan Co., Ltd.) is used as a rubber sheet, which has high shock absorption). Using a device, a tennis racket (manufactured by DUNNLOP,
PRO2000RIM SL3) Grip 21 of 20
, A tennis racket is arranged so that the face surface is positioned below, and in this state, when a tennis ball having a speed of 30 m / sec is volleyed, the 4 o'clock portion of the face surface of the racket, the throat portion, and the shaft 16 is a time waveform of a distortion applied to a portion (FIG. 15).

From FIGS. 12 and 13, the shaft portion at the moment when the ball collides with the face surface of the racket is shown when the human hits the tennis racket while holding the tennis racket and hits the ball while holding the tennis racket with the holder. Although the magnitude of the distortion is almost the same, it can be seen that the distortion immediately after that is very large when the tennis racket is held by the holder. In addition, when a person holds the tennis racket and hits the ball, the distortion attenuates with a periodic waveform, but when the person holds the tennis racket and hits the ball, the distortion is not periodic but has an irregular waveform. It turned out to be attenuating. Therefore, it is difficult to say that a conventional test hitting device holds a tennis racket in a state similar to a state where a person holds the tennis racket, and it cannot be said that a highly reliable test has been performed. there were.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and a holder of a hitting tool in a test hitting apparatus for performing a hitting test of a tennis racket or the like is brought closer to a state in which a person holds the hitting tool. It is an object to be able to hold a hitting tool.

[0011]

In order to solve the above-mentioned problems, according to the present invention, an elastic sheet is attached so as to include an air layer along an inner peripheral surface of a rigid cylindrical portion. The elastic sheet is inflated by injecting air into the air layer, and the elastic sheet is brought into elastic contact with the outer peripheral surface of the gripping portion of the hitting tool that has passed through the inner diameter of the cylindrical portion. There is provided a hitting tool holder of a hitting tool trial hitting device configured to be able to hold a holding portion while deforming an elastic sheet in response to movement of the holding portion with air pressure in an air layer.

Specifically, the elastic sheet attached to the inner peripheral surface of the cylindrical portion so as to include an air layer is made of an elastic tube having a hollow peripheral wall adhered to the inner peripheral surface of the cylindrical portion. An air injection passage is formed through the side wall of the cylindrical portion and the outermost wall of the elastic tube, and a check valve is provided in the air injection passage so that air injected into the tube from outside is sealed. (Claim 2).

An elastic sheet attached to the inner peripheral surface of the cylindrical portion so as to include an air layer inserts an elastic tube through an inner diameter portion of the cylindrical portion, and upper and lower ends of the cylindrical portion of the elastic tube. An air-injection passage which is formed by folding back an excess length portion protruding from the opening and tightly fixed to the outer peripheral surface of the cylindrical portion, and communicating with a gap between the inner peripheral surface of the cylindrical portion and the elastic tube on a side wall of the cylindrical portion. Is formed, and a check valve is provided in the air injection passage so that air injected into the gap from the outside is sealed.

In the hitting tool holder of the present invention, since the hitting tool is gripped by the elastic sheet (elastic tube) expanded by air pressure, it is possible to approximate a state where the ball is held by a human palm. That is, since the hitting tool is gripped by the elastic force of the elastic sheet and the air pressure, when the ball hits the hitting tool in the gripping state, the elastic sheet is largely deformed, and the hitting tool moves largely. Therefore, for example, when the player hits the ball while holding the tennis racket, the impact force at the time of hitting can be effectively mitigated, and the problem that distortion is concentrated on the shaft portion and the throw portion of the tennis racket can be eliminated. In the conventional holding device, a rubber sheet is covered on a portion of the hitting device to be held, but the rubber sheet only prevents the rigid fixing device from directly contacting the hitting device. When the ball hits the hitting tool, the hitting tool cannot move largely from its gripping position.

In the hitting tool holder of the present invention, it is preferable that the inner diameter of the cylindrical portion made of the rigid body is 140 to 230% of the outer diameter of the portion to be held by the hitting tool. When the inner diameter of the cylindrical portion is less than 140% of the outer diameter of the portion to be held by the hitting tool, for example, when the hitting tool is a tennis racket, the gripped grip portion is made of a rigid body due to movement at the time of a ball collision. May hit the inner peripheral surface of the cylinder,
The distortion of the shaft portion may increase. On the other hand, depending on the material of the elastic sheet (elastic tube), the elastic sheet needs to have elasticity and thickness that can withstand air pressure. However, if the elasticity or the thickness becomes too large, the elongation rate becomes small and the swelling does not expand sufficiently, so that it is difficult to obtain a stable gripping force. Conversely, if the stretchable material or thickness is reduced, the elongation will increase, but if the elongation is too high, it will be difficult to grip the hitting tool at the approximate center of the inner diameter of the cylindrical portion, or grip the tennis racket In this case, the gripped portion may hit the inner peripheral surface of the rigid cylindrical portion due to the movement at the time of the ball collision. Therefore, in order to grip the hitting tool with a stable gripping force at substantially the center of the inner diameter portion of the cylindrical portion, the sheet elastic modulus and the thickness of the rubber sheet are usually set in the range described later. However, even if the elastic modulus and the thickness of the elastic sheet are set in the ranges described below, when the inner diameter of the cylindrical portion is set to a diameter exceeding 230% of the outer diameter of the portion to be held by the hitting tool, the above ideal is obtained. It is difficult to obtain a grip state.

The height of the rigid cylindrical portion is not particularly limited, but is preferably equal to the width of a human palm (generally 50 to 90 mm). This corresponds to the case where a person actually holds the hitting tool with one hand. In addition, most tennis rackets hold the racket with one hand,
The racket may be gripped with both hands. Therefore, when measuring the mechanical characteristics of the racket when holding the racket with both hands, make the height of the cylindrical portion twice the width of the human palm, and adjust the size of the elastic sheet (elastic tube) accordingly. May be increased so as to approximate a state of being held by both hands.

The material of the elastic sheet (elastic tube) is not particularly limited, and various materials such as a natural or synthetic rubber sheet (tube), an elastomer sheet (tube), a fiber sheet formed by knitting non-stretchable fibers and rubber fibers, and the like can be used. (Elastic) sheet (tube) can be used. Particularly, a rubber sheet (tube) is preferable, and styrene-butadiene rubber (SBR), natural rubber (NR), butadiene rubber (BR), and ethylene-propylene rubber (EP
M), butyl rubber (IIR), halogenated IIR, chloroprene rubber (CR), chlorosulfonated polyethylene rubber (CSM), epichlorohydrin-ethylene oxide copolymer rubber (CIIC), epichlorohydrin homopolymer rubber (CHR), nitrile rubber (NBR) Hydride, chlorinated polyethylene, urethane rubber, silicone
Sheets (tubes) of ethylene propylene mixed rubber or the like are preferably used.

The elastic sheet (elastic tube) has a sheet elastic modulus of 5 × 10 ⁷ to 15 × 10 ⁷ dyn / cm.
² , preferably 8 × 10 ^{7 to} 13 × 10 ⁷ dyn / cm
² is good, and the sheet thickness is 1.0-2.
5 mm, preferably 1.25 to 2.0 mm.

The pressure applied to the hitting tool when a person holds the hitting tool varies depending on the sex of the person, the type of the hitting tool, the playing conditions at the time of hitting the ball, and for example, when the hitting tool is a tennis racket, The pressure applied to the grip of the racket during stroke, serve, is 0.5 to 2.0.
kgf / cm ² . Therefore, the air pressure in the elastic sheet (elastic tube) in a state where the hitting tool is gripped is 0.5 to 2.0 kgf / when the tennis racket is gripped.
It is preferably in the range of cm ² .

When the elastic modulus or thickness of the elastic sheet (elastic tube) is smaller than the above range, the sheet cannot withstand air pressure, the sheet itself is greatly deformed by elongation, and a stable and stable gripping force is obtained. Becomes difficult.
On the other hand, if it is larger than the above range, even if air pressure is applied, it does not expand sufficiently, and the force for gripping the racket becomes insufficient.

When the elastic sheet (elastic tube) is a rubber sheet (rubber tube), the loss tangent (tan δ) of the rubber at 24 ° C. is 0.1 to 0.5, preferably 0.15 to 0.5. It is preferable to use one in the range of 25. By being in this range, the shock absorbing property and the vibration damping property of the holder are further improved.

[0022]

Embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a hitting tool holder according to the first embodiment. The holder 100 has a thickness of 2 mm and a height of 70 mm.
On the inner peripheral surface 101a of the aluminum cylinder 101, an annular shape having a hollow peripheral wall having a height substantially equal to the height of the aluminum cylinder 101 and an outer peripheral length substantially equal to the inner peripheral length of the aluminum cylinder 101 is provided. The outer peripheral surface of the rubber tube 102 made of styrene-butadiene rubber (SBR) is adhered. Side wall 101b of aluminum cylinder 101 and rubber tube 1
In the outermost wall 103 adhered to the inner peripheral surface of the cylinder 101 of No. 02, an air injection passage 104 having a diameter of 4 mm penetrating therethrough is formed. I try to inject. A check valve 105 is provided inside the air injection passage 104 so that the air injected into the hollow portion 102a of the rubber tube 102 is sealed. Rubber tube 10
The air pressure in the second hollow portion 102a is adjusted by the amount of air injected from the outside. Although not shown here, the rubber tube 102 or the aluminum cylinder 1
An air pressure meter for measuring the air pressure in the tube may be attached to the side wall of the tube 01.

The hitting ball holder 100 is used by attaching it to a test hitting device for tennis. The height of the aluminum cylinder 101 is 70 mm, which corresponds to the width of the palm of a male adult. That is because

The gripping operation of the tennis racket by the holder 100 is usually performed as follows. First, holder 1
The grip part of the tennis racket is inserted into the inner diameter part of the aluminum cylinder 101 of No. 00. Then, the rubber tube 102 is passed through an air injection path 104 by an air pump (not shown).
Air is blown into the hollow portion 102a so that the inside of the hollow portion has a desired air pressure, the rubber tube 102 is expanded, and the grip portion of the tennis racket is
Pressing and gripping on the inner peripheral surface of. If the air pressure becomes too high, after air is injected, the check valve 105 in the air injection path 104 is pushed from the outside with a rod-shaped member to release the valve from closing, and the air in the tube 102 is released to the outside. You can also.

FIGS. 3 to 5 show a hitting tool holder according to a second embodiment. The hitting tool holder 200 has a diameter of 2 mm and a diameter of 70 mm in a part of the side wall of an aluminum cylinder 201. 4
mm through-hole 201a is formed, and a rubber tube 202 whose height is larger than that of the aluminum cylinder 201 is inserted into the inner diameter of the cylinder 201 (FIG. 3).
The extra length portions 202a and 202b protruding from the upper end and lower end openings of the
(See FIG. 4).

The through-hole 201a is provided in the rubber tube 202.
An air injection path for injecting air from the outside into the air layer 204 between the air layer 204 and the inner peripheral surface 201c of the cylinder 201. The air injected into the air layer 204 is sealed inside the air injection path 201a. Thus, the check valve 105 is provided. Note that the rubber tube 2 is also used in the holder 200.
02 or on the side wall of the aluminum cylinder 201, an air pressure meter for measuring the air pressure in the tube may be attached.

The holder 200 is used by being attached to a tennis hitting device in the same manner as the holder 100, and the operation of holding the tennis racket by the holder 200 is usually performed as follows. First, the grip part of the tennis racket is inserted into the inner diameter part of the aluminum cylinder 201 of the holder 200. The rubber tube 202 and the cylinder 2 are passed through an air injection passage 201a by an air pump (not shown).
Air is sent into the air layer 204 between the inner surface 201c and the inner surface 201c to expand the rubber tube 202, and the grip portion of the tennis racket is pressed and gripped by the inner surface of the rubber tube 202.

Test hitting experiment The holder 10 of the test hitting device shown in FIG.
6, except that 0 was replaced by the holder 200 of the second embodiment, and the thickness of the rubber tube 202 of the holder 200 made of styrene-butadiene rubber (SBR) rubber was changed. By changing the diameter, the inner diameter of the cylinder 201, and the like as described below, a test hitting (volley) test was performed as described above, and distortion at the time of collision at the 4 o'clock portion, the throat portion, and the shaft portion of the face surface of the racket was performed. Measure the amount of distortion (accurately about 13 mmsec after collision), the amount of distortion after collision (accurately about 16 mmsec after collision) (all of these are the maximum values), and the time waveform of the amount of distortion did. The racket is the same DUNNLOP as above.
And PRO2000RIM SL3 (35 mm outer diameter of the grip portion) were used to collide a tennis ball having a speed of 30 m / sec against the face surface of the racket.

(Experimental example 1) Aluminum cylinder has a thickness of 2 m
m, an inner diameter of 50 mm and a height of 70 mm were used.
A rubber tube made of styrene-butadiene rubber (SBR) rubber has a sheet elasticity of 9 dyn / cm ² , an outer diameter of 50 mm, a sheet thickness of 2.0 mm, and a height of 120 mm.
Was used. (Experimental example 2) Except that the sheet thickness of the rubber tube was 1.0 mm, it was the same as Experimental example 1. (Experimental Example 3) The same procedure as in Experimental Example 1 was conducted except that the inner diameter of the aluminum cylinder was 80 mm and the outer diameter of the rubber tube was 80 mm.

In each of the experimental examples, the air pressure in the air layer 204 inside the rubber tube 202 was 1 kg / kg.
cm ² . Table 1 shows the distortion amount immediately after the collision and the next distortion amount after the collision at the 4 o'clock portion, the throat portion, and the shaft portion of the face surface of the racket in each experimental example. 7 to 9 show time waveforms of distortion amounts applied to the 4 o'clock portion, the throat portion, and the shaft portion of the face surface of the racket in Experimental Examples 1 to 3, respectively. Table 1 also shows the amount of strain applied to the racket volleyed by the human and the amount of strain applied to the racket when using the conventional holder.

[0031]

[Table 1]

According to Table 1, FIGS. 7 to 9, FIG. 12 and FIG.
When the holder of the present invention is used, the strain applied to the racket at the time of hitting is very similar to the strain applied to the racket when a person grips and hits the racket, as compared to the case where the conventional holder is used. You can see that it is. In other words, the throat and the shaft of the racket are not greatly distorted in the same manner as when a human holds the racket and hits the ball, and the distortion applied to the racket is the same as when the human holds the racket and hits the ball. It was confirmed that the frequency was attenuated periodically.

Although the description has been made mainly of the content for holding a tennis racket, the holding device of the present invention is also applicable to a case where a hitting tool other than a tennis racket such as a badminton racket or a baseball bat is held. It goes without saying that you can do it.

[0034]

As is clear from the above description, according to the holder of the hitting ball test hitting device of the present invention, the bag is formed by inflating the bag made of a rubber sheet and using the elastic force of the rubber and the air pressure. By holding the hitting tool, the hitting tool can be held by approximating a state where a person holds the hitting tool. Therefore, it is possible to realize a state that is very similar to a state where a person actually hits the ball with the test hitting device, and it is possible to measure various characteristics such as shock absorption, durability and the like of the hitting tool in an actual use state from the test hitting device. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a perspective view of a hitting tool holder according to a first embodiment.

FIG. 2 is a sectional view of the hitting tool holder of the first embodiment.

FIG. 3 is a perspective view illustrating a manufacturing process of a hitting tool holder according to a second embodiment.

FIG. 4 is a perspective view of a hitting tool holder according to a second embodiment.

FIG. 5 is a sectional view of a hitting tool holder according to a second embodiment.

FIG. 6 is a side view showing an example of a test hitting device using the hitting tool holder of the second embodiment.

FIG. 7 is a time waveform diagram of a distortion amount applied to a tennis racket after hitting in Experimental Example 1 of the present invention.

FIG. 8 is a time waveform chart of a distortion amount applied to a tennis racket after hitting in Experimental Example 2 of the present invention.

FIG. 9 is a time waveform diagram of a distortion amount applied to a tennis racket after hitting in Experimental Example 3 of the present invention.

FIG. 10 is a perspective view of a tennis racket holder of a conventional tennis racket test hitting device.

FIG. 11 is a side view showing an example of a test hitting device using the holder shown in FIG.

FIG. 12 is a time waveform chart of distortion applied to a racket when a human volleys a tennis ball.

FIG. 13 is a time waveform diagram of the amount of distortion applied to the tennis racket after hitting the ball when the tennis racket is held by a conventional holder.

14A and 14B are a front view and a side view showing another example of the test hitting device using the holder shown in FIG.

FIG. 15 is a plan view of a tennis racket.

[Explanation of symbols]

 100, 200 Holder 101, 201 Aluminum cylinder 101a Inner peripheral surface of aluminum cylinder 101b Side wall of aluminum cylinder 102 Annular rubber tube 102 Hollow part 103 Tube wall 104, 201a Air injection path 105 Check valve 202 Rubber Tube 203-Hose band 204 Air layer

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01M 19/00 A63B 49/00

Claims (3)

(57) [Claims] An elastic sheet is attached so as to include an air layer along an inner peripheral surface of a cylindrical portion made of a rigid body, air is injected into the air layer to expand the elastic sheet, and the cylindrical portion is expanded.
On the outer peripheral surface of the gripper of the hitting tool passed through the inner diameter of
The elastic sheet is brought into elastic contact with the elastic force of the elastic sheet and the air.
Elastic sheet according to the movement of the gripping part with the air pressure in the layer
A hitting tool holder of a hitting tool test hitting device, wherein the hitting portion can be gripped while being deformed . 2. An elastic sheet attached to an inner peripheral surface of the cylindrical portion so as to include an air layer, the elastic sheet includes an elastic tube having a hollow peripheral wall adhered to an inner peripheral surface of the cylindrical portion. An air injection passage penetrating these is formed on the side wall and the outermost wall of the elastic tube, and a check valve is provided in the air injection passage so that air injected into the tube from the outside is sealed. The hitting tool holder of the hitting tool trial hitting device according to claim 1. 3. An elastic sheet attached to an inner peripheral surface of the cylindrical portion so as to include an air layer, wherein an elastic tube is inserted into an inner diameter portion of the cylindrical portion, and upper and lower ends of the cylindrical portion of the elastic tube. An air-injection passage which is formed by folding back an excess length portion protruding from the opening and tightly fixed to the outer peripheral surface of the cylindrical portion, and communicating with a gap between the inner peripheral surface of the cylindrical portion and the elastic tube on a side wall of the cylindrical portion. 2. The hitting tool holder of the hitting tool test hitting device according to claim 1, wherein a check valve is provided in the air injection path so that air injected into the gap from the outside is sealed. .