JPH07580A - Switching speed detector - Google Patents

Abstract

PURPOSE:To detect the Karman's vortex occurring along with the displacement of a bar or thread shape member without attaching any means on the member by detecting the Karman's vortex by a sound collection means with improved directivity and set so as to intersect an installing direction with a locus formed along with the displacement of the member, and calculating displacement speed from a detection result. CONSTITUTION:A sound collection device with high directivity is provided on the pressure receiving surface side of a condenser microphone 10 for audio equipment sold on the market by narrowly regulating the propagating path of a detected sound wave by inserting one end part of a cylinder 8 with both ends opened. A speed detector is formed by providing at least a pair of through holes 9 of small diameter on the wall surface of the cylinder 8 of the sound collection device, and mounting it on a housing 6 provided with a display window 7. The Karman's vortex along with the swing of a bat can be detected by adhering the detector on, for example, the home base of baseball. Displacement speed is calculated by the frequency of a detected Karman's vortex and it is displayed on the display window 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swing speed detecting device for detecting a swing speed of a golf club, a tennis racket, a baseball bat or the like.

[0002]

2. Description of the Related Art Conventionally, in a swing speed detecting device for this kind of sports equipment, for example, a device for detecting the rotational speed of the head of a golf club, a magnet is attached to the head with an adhesive tape or the like and generated from the magnet. The detected magnetic flux is detected as a magnetic flux change by a detection device including a Hall element installed at a specific position such as the ground surface, and the swing speed of the head is detected based on the magnetic flux change.

[0003]

However, in the case of the rotational displacement as described above, the centrifugal force corresponding to the rotational speed (or swing speed) acts on the magnet to swing the club. There is a risk that they will fly away and fly, so they have to swing around the club in a very dangerous state, so it is not a concern for the practitioner and cannot swing around the club as much as possible There was a problem. Further, since a magnet has to be attached to the club or the like, there is a problem that the weight of the club or the like changes, and the center of gravity position changes accordingly. Therefore, an object of the present invention is to provide a device capable of detecting the speed without attaching anything to a golf club or the like.

[0004]

A bar-shaped member swing speed detecting device according to the present invention detects Karman vortices generated by displacement of a rod-shaped or thread-shaped member by sound collecting means, and detects the detected Karman vortex. In a swing speed detecting device for calculating a displacement speed of the rod-shaped or thread-like member based on a frequency, the directivity of the sound collecting means is enhanced, and the installation direction of the sound collecting means is accompanied by the displacement of the rod-shaped or thread-like member. It is set so that it intersects with the locus formed.

[0005]

[Function] A sound collecting means such as a microphone having a high directivity is used for a baseball bat, a baseball bat
Install the rod-shaped member such as a golf club, the net of a tennis racket, etc. toward the portion of the rotational locus formed along with the displacement of the portion to be measured, and rotate the rod-shaped member or the filamentous member. It is possible to detect the speed at a desired position of the tip portion, the hand portion, and the middle portion of a baseball bat that is rotated (or swung) from the frequency of the generated Karman vortex.

[0006]

【Example】

[First Embodiment] The structure of a sound-collecting device 1 having a high directivity, which constitutes the present invention, will be described in detail with reference to FIG. In addition, in this embodiment, in order to obtain a small-sized sound collecting device 1 having high directivity, the following principle structure is adopted.

That is, here, a commercially available condenser microphone 10 for audio is used,
And on the pressure receiving side of the condenser microphone 10,
The sound collector 1 is fitted with one end of a cylinder 2 having openings at both ends.
Is configured. The condenser microphone 10 includes a cylindrical casing 11, a circuit board 12, and a FET.
It is composed of a transistor 13, an insulating cylinder 14 for maintaining a space, a pressure-receiving electret film 15a, a fixed electrode plate 15b, a ring-shaped insulating film 16 for spacers, a lead wire 17 for extraction, and the like.

That is, by inserting the pressure receiving surface side of the condenser microphone 10 into the cylinder 2 as described above, the propagation path of the detected sound wave is narrowed and the directivity of the condenser microphone 10 is enhanced. For example, in FIG. 1, when the cylinder 2 is not attached to the condenser microphone 10, a sound in the range of the divergence angle A is detected, whereas when the cylinder 2 is attached, the sound is wider than the divergence angle A. Only the sound in the range of the small spread angle B is detected, and the directivity can be improved.

The sound collecting device 1 having the enhanced directivity as described above is applied to the following device in this case, for example, a device for detecting the swing speed of the baseball bat 22.

That is, in FIG. 2, reference numeral 5 is a home base for baseball, which is formed by cutting a foldable material such as a cloth or a sheet into a pentagonal shape, through which the tip portion of the baseball bat 22 passes. For example, the swing speed detection device 3 of the baseball bat 22 according to the present invention is attached to the tip corner portion.

Next, the configuration of the swing speed detecting device 3 will be described in detail. That is, 6 is a housing,
The bottom portion is attached to the home base 5 with Velcro (registered trademark), glue, or the like. Reference numeral 7 denotes a display portion provided in a display window portion 7 provided on the upper surface of the housing 6, and a display device 31 is provided in the window portion 7 so that it can be seen from the outside.

Reference numeral 8 denotes a cylinder (reference numeral 2 in FIG. 1) provided to enhance the directivity of the condenser microphone 10.
At least a pair of through-holes 9 having a minute diameter are provided in the wall surface so as to penetrate the wall surface, and the holes 9 and 9 arranged in a group and arranged to face each other enter. The incoming sounds interfere with each other and cancel each other out. That is, when sounds coming from the side enter into the cylinder 8 through the holes 9 and 9 of the set that are desired to be arranged to face each other, they interfere with each other and are erased, and only the sound coming from the tip end of the cylinder 8 enters the condenser microphone 10. It is configured to be propagated.

The cylinder 8 is fitted and attached to a circumferential wall 20 formed so as to project from a corner portion of the housing 6, and is formed inside the circumferential wall 20. The condenser microphone 10 is disposed in the hole 21. Further, the wall surface of the cylinder 8 penetrates the inner and outer surfaces of the cylinder 8 and is symmetrically arranged so that at least one set of the noise removing pores 9 (two sets as shown in FIG. 4 in this embodiment). ) It is provided.

Reference numeral 20 denotes a cylindrical wall which is provided in a circular shape at the corner of the housing 6 as described above and which has the condenser microphone 10 disposed therein, and which constitutes a mounting portion. The inner peripheral surface of 8 is fitted and the cylinder 8 is attached to the housing 6.

Next, an electronic circuit connected to the condenser microphone 10 having the above structure will be described with reference to FIG. In FIG. 5, reference numeral 25 denotes a bandpass filter for removing noise superimposed on the analog detection signal supplied from the condenser microphone 10. Reference numeral 26 is an A / D converter, which converts an analog detection signal supplied from the band pass filter 25 into a digital signal, and a microcomputer 29 described later.
Supply to. A thickness setting changeover switch 27 is provided with a plurality of switches (not shown).
It is for input used to set the thickness of the portion to be measured in the microcomputer 29.

Reference numeral 28 denotes a memory, which stores a detection frequency and a speed corresponding thereto in a one-to-one correspondence format, and when a value of the detection frequency is supplied from a microcomputer 29, which will be described later, a speed signal corresponding to the detected frequency Supply to the computer 29.

Reference numeral 29 is a microcomputer, which is the A /
When the digital detection signal supplied from the D converter 26 is received, the frequency spectrum of the detection signal is calculated (the spectrum diagram shown in FIG. 6 is obtained), and the frequency spectrum is calculated from the frequency spectrum (see FIG. 6). The frequencies f0 and f1 showing two peak values are calculated, and the calculated values f0 and f
An intermediate value f2 of 1 is obtained as a frequency corresponding to the swing speed of the baseball bat 22 (speed when the baseball bat 22 passes over the tip portion of the cylinder 8). Further, the microcomputer 29 obtains and displays the swing speed from the memory 28 based on the obtained frequency f2 and the signal indicating the thickness of the measurement portion of the measurement object such as a baseball bat from the thickness setting changeover switch 27. The display signal is supplied to the display unit 31 via the control unit 30. It should be noted that the microcomputer 29 stops the supply of the display signal and resets the program processing in the microcomputer 29 when a predetermined time elapses after starting the output of the display signal to the display control unit 30, and again. To start.

Next, the operation of the above structure will be described with reference to FIGS.
Will be described with reference to. As shown in FIG. 7, while the baseball bat 22 makes a sound passing through the center of the cylinder 8 and toward the straight line L indicating the sky (that is, sound is generated by the Karman vortex 23 being generated), For example, when approaching from position A at speed V, cylinder 8 is caused by the Doppler effect.
The frequency of sound traveling in the direction becomes higher. Further, when the velocity V is passed through the straight line L and moved to the position B, the frequency of the sound due to the Karman vortex 23 is propagated toward the cylinder 8 on the contrary due to the Doppler effect.

That is, when the swing speed V of the baseball bat 22 is observed as shown in FIG. 7, frequency spectra forming peaks M and N at frequencies f0 and f1 are observed as shown in FIG. That is, the microcomputer 29 in the circuit shown in FIG. 5 obtains the intermediate frequency f2 (= (f0 + f1) / 2) by obtaining the frequencies f0 and f1 in FIG. Then, the microcomputer 29 refers to the frequency f2 thus obtained and the signal from the thickness setting changeover switch 27 indicating the thickness of the measurement portion of the baseball bat 22 and refers to the data stored in the memory 28 to determine the speed V. Is displayed and the display signal is displayed on the display unit 31 via the display control unit 30. Further, when a predetermined time has elapsed after the display, the supply of the display signal is automatically stopped and the initial state is restored. When the baseball bat 22 is shaken again, the swing speed at that time is displayed on the display unit 31.

[Second Embodiment] The configuration will be described with reference to FIGS. 8 and 9. In FIGS. 8 and 9, the same components as those shown in FIGS. 2, 3 and 5 are designated by the same reference numerals and only the different portions will be described in detail below. That is, 40 has the same function as the home base 5 in FIG. 2, but is formed of a hard material that emits a sound of a specific frequency when the upper surface E thereof is hit with the tip of the baseball bat 22. Reference numeral 41 denotes a second condenser microphone provided in the housing 6 for detecting a sound generated by hitting the upper surface E of the home base 40, and the first condenser microphone 41 is the condenser of the first embodiment. It is the same as the microphone 10.

Reference numeral 42 is a second band pass filter 42 for extracting a sound of a specific frequency emitted when the upper surface of the home base 40 is hit by the baseball bat 22. Reference numeral 43 is a second A / D converter for converting the signal supplied from the second bandpass filter 42 into a digital signal.

44 has the following functions added to the functions of the microcomputer 29. That is, the microcomputer 44 obtains the frequency spectrum of the signal supplied from the second A / D converter 43, and when the sound of the specific frequency emitted from the home base 40 is detected from the frequency spectrum, it is detected. Resets the operation of the microcomputer 44 in preparation for frequency analysis of the signal supplied from the first A / D converter 26.

Next, in the above structure, when the batter stands by the side of the home base 40 holding the baseball bat 22 and hits the tip of the baseball bat 22 against the upper surface of the home base 40, the sound produced in response to the second sound is generated. The frequency spectrum detected by the condenser microphone 41 is analyzed by the microcomputer 44, and the microcomputer 44 is reset and set to the initial state.

After that, when the batter swings around the baseball bat 22 and makes a sound by the Karman vortex 23, the sound is supplied to the microcomputer 44 via the first condenser microphone 10. As a result, the microcomputer 44 obtains the frequency spectrum as shown in FIG. 6, and based on the intermediate frequency f2 obtained as a result and the signal indicating the thickness of the measurement portion set by the thickness setting changeover switch 27, the baseball. The swing speed V of the bat 22 is calculated and displayed on the display 31, and continues to be displayed. Then, when the batter hits the upper surface E of the home base 40 again with the baseball bat 22, the microcomputer 44 is initialized and the display on the display 31 disappears.

[0025]

As described above, according to the present invention,
Since the swing speed of a baseball bat or the like can be measured without attaching anything to the baseball bat or the like, it is possible to detect the swing speed in a very natural form, so that an extremely great effect is exhibited.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing a configuration for enhancing directivity of a microphone used in each embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining a first embodiment according to the present invention.

FIG. 3 is a cross-sectional explanatory view of a main part in FIG.

4 is an XY cross-sectional explanatory view in FIG. 3 for explaining a hole 9 provided in the cylinder 8. FIG.

FIG. 5 is a circuit block diagram used in the first embodiment according to the present invention.

FIG. 6 is a diagram for explaining changes in the frequency spectrum of the sound detected by the condenser microphone 10 before and after passing directly above the cylinder 8 constituting the present invention.

7 is an explanatory diagram for explaining FIG. 6; FIG.

FIG. 8 is an explanatory diagram for explaining a second embodiment according to the present invention.

FIG. 9 is a circuit block diagram used in the second embodiment.

[Explanation of symbols]

 2, 8 Cylinder 5, 40 Home base 6 Housing 7 Display window 9 Hole 10, 41 Condenser microphone 25, 42 Bandpass filter 26, 43 A / D converter 27 Thickness setting change switch 28 Memory 29, 44 Microcomputer 30 Display control Part 31 Display

Claims (1)

[Claims] 1. A swing for detecting a Karman vortex generated by the displacement of a rod-shaped or thread-like member by a sound collector and calculating a displacement speed of the rod-shaped or thread-shaped member based on the frequency of the detected Karman vortex. In the velocity detecting device, the directivity of the sound collecting means is enhanced, and the installation direction of the sound collecting means is set so as to intersect with a locus formed by the displacement of the rod-shaped or thread-like member. Speed detection device.