JPS61186859A - Measuring instrument for swing speed - Google Patents

Abstract

PURPOSE:To measure the swing speed of a swing body like a bat even when a flying ball is hit by providing a couple of acceleration sensors to the swing body and calculating the integral value of acceleration as a speed. CONSTITUTION:The couple of acceleration sensors 3 are arranged so as to cross each other at right angles in a plane crossing the lengthwise direction of the bat 1 at right angles. Each sensor 3 is made of a piezoelectric body and when the bat 1 is accelerated, a voltage corresponding to variation in pressure operating on the piezoelectric body is led out, thereby measuring the acceleration. Voltages led out of both sensors 3 are converted into digital signals by an arithmetic circuit 4 to calculate the square root of the sum of the accelera tion; and the integral value of the acceleration is calculated until the accelera tion becomes 0 and the integration is completed when the acceleration becomes 0. Then, the integral value is displayed 5. The bat 1 enters rotary motion around its lengthwise axis, and the sensors 3 are arranged at right angles, so the actual acceleration is found.

Description

[Detailed Description of the Invention] [Technical Field 1] The present invention relates to a swing speed measuring device, more specifically,
The present invention relates to a swing speed measuring device that measures the speed when swinging a swinging object such as a bat or a racket.

(Background technology 1) Devices that measure the speed of swinging objects such as baseball bats, tennis and badminton rackets, and golf clubs have conventionally measured the head speed of golf clubs as shown in Figure 13. This is a device in which a pair of sensors 20 for detecting the passage of the club head are placed a predetermined distance apart before and after a position 21 where the ball is set. By determining the time difference when the head passes, the club head speed can be calculated and displayed on the display section 22.

In this measuring device, the sensor 20 is placed apart from the club, and the club must pass within the detection areas of both sensors 20, so the position at which the club is swung is restricted to the mounting position of the sensor 20. When hitting a flying ball like a baseball, the sensor 20
There is a problem in that it is virtually impossible to swing the swing body in the detection area, and it is impossible to measure the swing speed when hitting a flying ball.

[Objective of the Invention 1 The present invention has been made in view of the above points, and its main purpose is to enable measurement of swing speed even when hitting a ball with a swinging body. An object of the present invention is to provide a swing speed measuring device.

[Disclosure of the Invention 1 (Examples) Examples of the present invention will be described below based on the drawings. In this embodiment, a baseball bat is exemplified as the swing body 1. As shown in FIG. 1, a belt-shaped device main body 2 is attached to the surface of a bat 1, and an acceleration sensor 3
, a battery 7 serving as a power supply section 6, a microprocessor 8 constituting an arithmetic circuit 4, a display section 5 such as a liquid crystal display, a power switch 9, etc. are provided. The acceleration sensor 3 is composed of a piezoelectric material, and by sandwiching the piezoelectric material between an inertial body (not shown) having a relatively large mass, the piezoelectric material detects when the bat 1 is accelerated. Acceleration is measured by extracting the voltage that corresponds to changes in the applied pressure. In other words, the action of force is proportional to acceleration, so when the speed of swinging the bat 1 changes, pressure proportional to the acceleration acts on the piezoelectric body, and the voltage generated from the piezoelectric body in response to this pressure is measured. By doing this, acceleration can be measured. A pair of acceleration sensors 3 are provided, and the double-jaw speed sensors 3 are arranged in directions perpendicular to each other in a plane perpendicular to the longitudinal direction of the bat 1.

The signal taken out from the both-jaw speed sensor 3 is input to an arithmetic circuit 4, as shown in FIG. The arithmetic circuit 4 converts the voltages taken out from the two-jaw speed sensor 3 into h digital signals, and as shown in FIG. 3, the two-jaw speed sensor 3
The square root of the sum of the squares of the output values a× and ay is determined as the acceleration magnitude lal, and the acceleration magnitude is 0.
The integral value of the acceleration is calculated until the magnitude of the acceleration becomes O, and the integration is terminated.

This integral value is then input to the display section 5, and the integral value of acceleration is displayed.

The relationship between speed and acceleration when swinging the bat 1 is approximately as shown in FIG. 4.

That is, if you start swinging the bat 1 at time t0, the initial speed at that time is O, it gradually accelerates and reaches the maximum speed at time t1, and then decelerates and finishes swinging the bat 1 at time t2. The velocity becomes O, and in an idealized state, the acceleration changes along a substantially sinusoidal curve. However, when the bat 1 reaches the maximum speed, the direction of the acceleration is reversed, so the maximum speed is reached when the acceleration becomes 0 for the first time after the bat 1 starts swinging. In other words, to find the maximum speed,
All you have to do is integrate the acceleration from when you start swinging the bat 1 until the acceleration becomes 0. By the way, when swinging the bat 1, there is a complex combination of linear and circular motions caused by the movements of a person's hips, arms, wrists, etc.
As shown in FIG. 5, the bat 1 rotates around its longitudinal direction as an axis. When such a rotational movement occurs, the direction of the force acting on the acceleration sensor 3 changes, and each acceleration sensor 3 measures the magnitude of the acceleration vector corresponding to the direction of the acceleration sensor 3. . However, by calculating the resultant force of the forces acting on the two acceleration sensors 3, the acceleration of the bat 1 can be obtained. , the actual magnitude of the acceleration can be determined by finding the square root of the sum of squares of the magnitude of the acceleration acting on the both-jaw speed sensor 3. This operation is shown in FIG.

In the above embodiment, the maximum velocity is determined by integrating the magnitude of acceleration from when the bat 1 starts swinging until the acceleration reaches O, but the integral value of the magnitude of acceleration at each time is If this is recorded with an X-Y recorder or the like, it is possible to measure changes in velocity, and it can also be used to measure changes in velocity due to impact when the ball collides with the bat 1.

Furthermore, by changing the dimensions of the device main body 2, it is possible to attach it to a tennis or badminton racket, a golf club, etc. in addition to the bat 1 as a swinging body.

(Embodiment 2) In Embodiment 2, an example will be shown in which the magnitude of acceleration can be measured using one acceleration sensor 3.

As shown in FIGS. 6 and 7, the acceleration sensor 3 is formed in a cylindrical shape, and includes a cylindrical weight 10 and a piezoelectric material wound around the entire circumference of the weight 10. It consists of a piezoelectric body 11 made of organic polymeric material, a cylindrical inertial body 12 that holds the piezoelectric body 11 between it and a weight 10, and a lid body 13 that closes both the upper and lower surfaces of the inertial body 12, respectively. has been done. The piezoelectric body 11 is formed into a rectangular shape as a weight 1.
0, and terminal wires 14 are drawn out from both the front and back sides.

Therefore, the 0-axis direction of the acceleration sensor 3 and the longitudinal direction of the swing body 1 are made to coincide with each other, so that the acceleration sensor 3
When attached to the swing body 1, pressure is applied to the piezoelectric body 11 between the weight 10 and the inertial body 12 when the swing body 1 is swung, and an electromotive force corresponding to the magnitude of acceleration can be extracted. It is. Here, the acceleration sensor 3 is a cylindrical weight 1
Since it is wrapped around the entire circumference of the 0, there is no directionality in the plane orthogonal to the 0 Tsumugi direction, and as shown in Example 1, the swing body 1 is wrapped around the axis along the direction of the technique. Even if the sensor rotates in the opposite direction, the magnitude of the acceleration can be measured regardless of the position of the acceleration sensor 3.

As shown in FIG. 8, this acceleration sensor 3 is attached to a belt-shaped device main body 2, and the device main body 2 is wrapped around the swing body 1. The device main body 2 includes a microprocessor 8 as an arithmetic circuit 4 that performs predetermined arithmetic operations on the output of the acceleration sensor 3 to calculate speed, a display section 5 such as a liquid crystal display that displays the output of the arithmetic circuit 4, and a power supply section. A battery 7 as 6 and a power supply switch 9 are provided. That is,
The acceleration sensor 3, the calculation circuit 4, the display unit 5, and the power supply unit 6 are connected as shown in FIG. 9, and the calculation circuit 4 calculates the speed based on the magnitude of acceleration detected by the acceleration sensor 3. This is displayed on the display section 5. Incidentally, when detecting the maximum speed when swinging the swing body 1, the arithmetic circuit 4 integrates the magnitude of the acceleration from when the swing body 1 starts swinging until the acceleration reaches O, as shown in FIG. , the integration is finished when the acceleration reaches O, and the integrated value is output to the display unit 5. In the manner described above, the maximum speed can be displayed. Here, since there is only one acceleration sensor 3, there is no need to calculate the square root of the sum of squares of the output values of the pair of acceleration sensors 3, and the calculation is simplified as shown in FIG. 10.

(Example 3) What is shown in FIGS. 11 and 12 is an acceleration sensor 3
This is an improved version of Example 2, and piezoelectric body 1
1 is shaped like a parallelogram I# as shown in FIG. 11, and is designed to be wrapped around a weight 10. That is, in this parallelogram, the piezoelectric body 11 is a weight 10
A shape in which a right angle is sandwiched between a side of ml having a length equal to the total length of the circumference of a cylinder formed by winding it around the cylinder, and a second side having a length equal to the total length of the cylinder in the 0-axis direction. It is formed by aligning the second sides of a right triangle formed in , so that the hypotenuses are parallel. By winding the parallelogram-shaped piezoelectric body 11 around the weight 10, the discontinuous portion of the piezoelectric body 11 is
1, so that no singular point is formed over the entire circumference of the piezoelectric body 11 in the circumferential direction, and it is possible to prevent the piezoelectric body 11 from having any directionality. be.

[Effect of the Invention 1] As described above, the present invention includes an acceleration detecting means for detecting acceleration in a direction perpendicular to the longitudinal direction of a swinging body such as a bat or a racket, and a small amount of acceleration in directions perpendicular to each other;
a calculation means for calculating the integral value of the acceleration detected by the acceleration detection means as a speed; a display means for displaying the output result of the calculation means; and a device body in which each of the above means is installed and detachably connected to the swing body. The device is attached directly to the swinging body, and the speed can be measured without the swinging position of the swinging body being restricted by the device, such as when hitting a flying ball. However, it has the advantage that the swing speed of the swing body can be measured. Furthermore, since the acceleration detection means is arranged to detect acceleration in a direction perpendicular to the longitudinal direction of the swing body and at least in directions perpendicular to each other, even if the swing body rotates around its longitudinal direction, the measured value This has the advantage that no error occurs.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the first embodiment of the present invention, FIG. 2 is a block diagram of the same as above, FIG. 3 is a diagram explaining the operation of the arithmetic circuit used in the same, FIG. The figure is an explanatory diagram of the same operation as above, FIG. 6 is a perspective view showing a state in which the lid of the acceleration sensor used in the second embodiment of the present invention is removed, and FIG. 7 is a state in which the lid of the acceleration sensor used in the above is attached. FIG. 8 is a perspective view showing the same as above, FIG. 9 is a block diagram of same as above,
Fig. 0 is an explanatory diagram of the operation of the same arithmetic circuit as above, Fig. 11 is a perspective view showing Embodiment 3 of the present invention with the lid removed, Fig. 1 is a developed view showing the piezoelectric body used in the above, Fig. FIG. 13 is a plan view showing a conventional example. 1 is a swing body, 2 is a device main body, 3 is an acceleration sensor, 4
is an arithmetic circuit. Agent Patent Attorney Ishi 1) Chief 7 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 (a) (b) (c) Figure 7
Figure 6 Figure 9 Figure 10 Figure 11 Figure 13

Claims (4)

[Claims] (1) An acceleration detection means for detecting acceleration in a direction perpendicular to the longitudinal direction of a swinging object such as a bat or a racket, and at least in directions perpendicular to each other, and an integral value of the acceleration detected by the acceleration detection means is calculated as velocity. a calculation means for displaying an output result of the calculation means;
A swing speed measuring device comprising a device main body in which each of the above means is installed and detachably connected to the swing body. (2) The acceleration detection means is comprised of a pair of acceleration sensors, each of which is arranged so as to detect acceleration in a direction perpendicular to the longitudinal direction of the swing body and perpendicular to each other. A swing speed measuring device according to claim 1. (3) The acceleration detecting means is an acceleration sensor formed in a cylindrical shape, and the device main body is attached to the swing body so that the mouth axis direction of the acceleration sensor is parallel to the longitudinal direction of the swing body. A swing speed measuring device according to claim 1, characterized in that: (4) The acceleration sensor has a cylindrical shape formed by rounding a parallelogram so that its hypotenuses overlap each other, and the parallelogram has a first diameter having a length of the entire circumference in the circumferential direction of the cylinder. A pair of right triangles sandwiching a right angle between the side of 4. The swing speed measuring device according to claim 3, wherein the swing speed measuring device is formed into a shape.