JPH03140169A - Centroid measuring instrument for ball hitting tool - Google Patents

Abstract

PURPOSE:To display the weight and the centroidal position of a ball hitting tool by measuring a load at a ball hitting part side with a first load measuring means and the load at a grip side with a second load measuring means, and computing the load from measured loads and a distance between first and second fulcra and a distance between an abutting body and the second fulcrum. CONSTITUTION:A racket frame 18 is placed on a first racket fulcrum 19 fitting in the center of a scale 26, and the grip 20 is placed on a second racket fulcrum 21, and a grip end 20a is abutted with the abutting body 22. A load cell 23 measures the load at a racket frame 18 side, and a load cell 24 measures the load at the grip 20 side of the racket 17, and the adder 45 of a CPU 44 computes the weight of the racket 17, and a weight display 39 displays the weight of the racket 17. Also, the CPU 44 computes the distance from the abutting body 22 to the centroidal position of the racket 17 based on the measured load and the distance between the first and second racket fulcra 19, 21, and the distance between the abutting body 22 and the racket fulcrum 21, and a weight position display 40 displays the centroidal position.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a center of gravity measuring device for a ball hitting tool, such as a tennis racket, for measuring the center of gravity of a ball hitting tool such as a tennis racket.

BACKGROUND OF THE INVENTION When a tennis racket 1- (hereinafter referred to as a racket) or other ball-striking tool is gripped with a grip 2 in the hand and a swing is made, as shown in FIG. There is a fulcrum S that is thought to be the center around which the posture of the robot swings.

When swinging a racket 1 with the same weight W, due to the rotational moment of the center of gravity relative to the fulcrum S during the swing of the racket 1, if the center of gravity G of the racket 1 is close to the tip of the racket frame 3, the racket 1 will If the swing feels heavy and the center of gravity G of racket 1 is close to the fulcrum S, the swing of racket 1 will feel light,
Even when swinging rackets 1 with different weights W, the weight of the swing feels the same depending on the position of the center of gravity G of the racket 1.

The conventional center of gravity measuring device for a ball hitting tool, as shown in Fig. 8,
A support 6 is erected on the top of the base 5, a rod 7 is swingably provided on the support 6, a pedestal 8 on which the racket frame 3 of the racket 1 is placed is provided on one end of the rod 7, and a support 8 is provided on the other end of the rod 7. A contact body 9 that abuts the grip end 2a of the racket 1 is provided, a weight 10 is movably provided between the support 6 of the rod 7 and the contact body 9, and a weight 10 is movably provided between the support 6 of the rod 7 and the grip end 2a of the racket 1. A scale 11 was provided to indicate the position of the center of gravity for balance.

Problems to be Solved by the Invention However, in the conventional center of gravity measuring device for a ball hitting tool, when measuring the position of the center of gravity G of the racket 1, the racket frame 3 of the racket 1 is placed on the pedestal 8, and the grip end of the racket 1 is After placing the racket 1 on the rod 7 by bringing the racket 2a into contact with the contact body 9, the weight 10 is moved by hand along the longitudinal direction of the rod 7, and the rod 7 is placed horizontally with respect to the support 6. Balance with a weight 10 so that the rod 7
Scale 1 corresponds to the position of the weight 10 in a balanced state.
1 to measure the position of the center of gravity of the racket 1, the measurement work is time-consuming and troublesome, and the work efficiency is poor when measuring the center of gravity of a large number of rackets 1
It was also difficult to read the weight of the racket 1 and the center of gravity position had to be measured separately.

An object of the present invention is to solve the above-mentioned problems by placing a ball-hitting tool on a first fulcrum and a second fulcrum, and by abutting the grip end of the ball-hitting tool on a contact body, the first load can be reduced. The measuring means measures the load on the ball hitting part side of the ball hitting tool, the second load measuring means measures the load on the grip side of the ball hitting tool, and the weight calculating means measures the measured load of the first load measuring means and the second load measuring means. The weight of the ball hitting tool is calculated from the measured load of the load measuring means, the weight of the ball hitting tool calculated by the weight calculating means is displayed on the weight display, and the center of gravity position calculating means is connected to the first load measuring means and the second load measuring means. The distance from the abutting body to the center of gravity of the ball hitting tool is calculated based on the measured load of the means, the distance between the first fulcrum and the second fulcrum, and the distance between the abutting body and the second fulcrum, and a center of gravity position indicator is calculated. displays the center of gravity position of the ball hitting tool calculated by the center of gravity position calculation means;
Measurement work can be done quickly and effortlessly, improving work efficiency, and all you need to do is look at the weight display and center of gravity position display.
To provide a center of gravity measuring device for a ball hitting tool which can easily read the weight and center of gravity position of the ball hitting tool and can simultaneously measure the weight and center of gravity of the ball hitting tool.

Means for Solving the Problems The device for measuring the center of gravity of a ball hitting tool according to the present invention includes a first fulcrum and a second fulcrum that support the ball hitting tool at an interval above a scale stand, and a first fulcrum and a second fulcrum that support the ball hitting tool. A contact body for abutting the grip end of the ball hitting tool is provided on the side of the second fulcrum, and first and second load measuring means are provided at lower portions of the scale stand at positions corresponding to the first and second fulcrums. and communicating the first load measuring means and the second load measuring means to a weight calculating means for calculating the weight of the ball hitting tool based on the measured loads of the first and second load measuring means, and Depending on the measured loads of the first and second load measuring means, the distance between the first fulcrum and the second fulcrum, and the distance between the abutting body and the second fulcrum, the distance between the abutting body and the ball hitting tool is determined. The center of gravity position calculation means is connected to a center of gravity calculation means that calculates the distance to the center of gravity, the weight calculation means is connected to a weight display that displays the weight of the ball hitting tool, and the center of gravity calculation means is connected to the center of gravity that displays the center of gravity position of the ball hitting tool. It has a configuration characterized in that it communicates with a position indicator.

A ball-striking tool is placed on a first fulcrum and a second fulcrum that are spaced apart from each other on the upper part of the weighing scale, and the grip end of the ball-striking tool is placed on a contact body provided on the side of the second fulcrum. When it comes into contact with
The first fulcrum and the second fulcrum support the ball-striking tool, and the first load measuring means provided at the bottom of the scale stand at a position corresponding to the first fulcrum measures the load on the ball-striking section side of the ball-striking tool. A second load measuring means provided at the lower part of the scale stand at a position corresponding to the second fulcrum measures the load on the grip side of the ball hitting tool.

Further, the weight calculating means communicating the first load measuring means and the second load measuring means calculates the weight of the ball hitting tool based on the measured load of the first load measuring means and the measured load of the second weight measuring means. At the same time, the center of gravity position calculation means calculates the ball hit from the abutting body based on the measured loads of the first and second load measuring means, the distance between the first fulcrum and the second fulcrum, and the distance between the abutting body and the second fulcrum. The distance to the center of gravity of the tool is calculated, the weight display connected to the weight calculation means displays the weight of the hitting tool calculated by the weight calculation means, and the center of gravity position display connected to the center of gravity position calculation means calculates the center of gravity position. The center of gravity position of the ball hitting tool calculated by the means is displayed.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

In FIG. 1, reference numeral 15 denotes a frame body, and a long scale stand 16 is provided horizontally on the upper part of the frame body 15, and a racket frame 1 of a racket 17 is placed on the upper part of the scale stand 16 at intervals.
A first racket fulcrum 19 with an inverted ■-shaped cross section that supports the racket 17 and a second racket fulcrum 21 with an inverted V-shaped cross section that supports the grip 20 of the racket 17 are provided. A contact body 22 for contacting a grip end 20a of the racket 17 is provided on the side.

A load cell 23 serving as a first load measuring means is provided at the lower part of the scale stand 16 at a position corresponding to the first racket fulcrum 19, and a load cell 23 serving as a first load measuring means is provided at the lower part of the scale stand 16 at a position corresponding to the second racket fulcrum 21. A load cell 24 serving as a second load measuring means is provided.

As shown in FIG. 2, the first racket fulcrum 19 is formed to intersect with the longitudinal direction of the scale stand 16 and have a length between the width of the frame 15 and the width of the frame 15, and the second racket fulcrum 21 is formed to intersect the longitudinal direction of the scale stand 16. The second racket fulcrum 21 is arranged parallel to the first racket fulcrum 19.

As shown in FIG. 3, the first racket fulcrum 19 is horizontally provided at the upper part of the scale stand 16 near one end 16a via a support plate 25, and the first racket fulcrum 19 is provided along the longitudinal direction. A scale 26 is provided for placing the racket frame 18 of the racket 17 on the center of the first racket fulcrum 19. The contact body 22 is installed horizontally on the upper part near the scale 16b with a support plate 27 interposed therebetween.
6 is erected at the other end 16b.

The first racket fulcrum 19 and the second racket fulcrum 21 are arranged so that the racket frame 18 is in a horizontal state when the racket 17 is placed above the first racket fulcrum 19 and the second racket fulcrum 21. Second racket fulcrum 2
1 is located slightly below the first racket fulcrum 19.

A base plate 28 is integrally provided inside the frame 15, and a bracket 29 supporting the load cell 23 below the first racket fulcrum 19 is provided on the upper part of the base plate 28.
A bracket 30 for supporting the load cell 24 is provided below the second racket fulcrum 21.

At the top of the load cell 23 and the load cell 24, joint bodies 31 and 31 each having a trowel-shaped cross section are provided.
．． As shown in FIGS. 3 and 4, the scale stand 16 is horizontally installed on the top of the scale 31 via a plurality of ball joints 32, 32 having steel balls.

A power source 33 is provided on the side of the load cell 23 at the upper part of the base plate 28 inside the frame 15, and a load cell amplifier 34 is provided between the power source 33 and the load cell 24.
A zero and span volume mechanism 35 is provided on the side of the load cell 24.

A level 36 is provided on the earthen wall of the frame 15 to set the frame 15 in a horizontal state, and a plurality of legs 37 for horizontal adjustment are provided at the four corners of the lower part of the frame 15 so as to be movable in the vertical direction. Each is provided.

A power button 38 is provided on the inclined wall of the frame 15, a weight indicator 39 for displaying the weight of the racket 17 is provided on the side of the power button 38, and a weight indicator 39 for displaying the weight of the racket 17 is provided on the side of the weight display section 39. A center of gravity position indicator 4o is provided to display the position of the center of gravity to be balanced, and a weight indicator 39 and a center of gravity position indicator 40 are provided between the power switch 38 and the weight indicator 39.
A zero set button 41 is provided to set the display to zero.

FIG. 5 shows a schematic block diagram of the present invention, in which the load cell 23 is connected to an A/D converter 42 via a load cell amplifier 34, and the load cell 24 is connected to an A/D converter 42 via a load cell amplifier 34. Vessel 43 was contacted,
The A/D converter 42 and the A/D converter 43 measure the measured load of the load cell 23 and the measured load of the load cell 24, the distance between the first racket fulcrum 19 and the second racket fulcrum 21, and the distance between the abutting body 22 and the second racket fulcrum. The racket 17 is connected to a central processing unit (hereinafter referred to as CPU) 44 which is a center of gravity calculation means for calculating the distance from the contact body 22 to the center of gravity of the racket 17 based on the distance from the racket fulcrum 21 of the racket 17.

The load cell amplifier 34 is connected to the zero volume and span volume of the zero and span volume mechanism 35, respectively.

The CPU 44 includes an adder 45 serving as a weight calculating means for calculating the weight of the racket 17 based on the measured load of the load cell 23 and the measured load of the load cell 24, and a first racket fulcrum 19 and a second racket fulcrum 2 for the measured load of the load cell 23.
A divider 46.4t divides the summation result of the adder 45 by the summation result of the distance from An adder 47 for addition is provided.

The power source 33 is communicated to the CPU 44 via the power button 38, and the zero set button 41 is communicated to the CPU 44.
There is C.

The CPU 44 is connected to a weight display section 39 that displays the weight of the racket 17 and a center of gravity position display 40 that displays the center of gravity position of the racket 17.

FIG. 6 shows a principle diagram of measuring the centering of the racket 17.

Place the racket frame 18 of the racket 17 on the first racket fulcrum 19, and place the racket 18 on the second racket fulcrum 21.
7, the grip end 20a is brought into contact with the contact body 22, and the racket 17 is placed on the first racket fulcrum 1.
9 and the second racket fulcrum 21, the weight W of the racket 17 is: W=R1+R2...(1) The distance between the first racket fulcrum 19 and the second racket fulcrum 21 is a, the distance between the abutting body 22 and the second racket fulcrum 21 is the center of gravity G of the racket 17 balanced from the abutting body 22. If the distance to the position is L, then (L-b)W=aR1-(2), and from equation (2), L= (aR1/W)+b-(3),'
Substituting equation (1) into equation (3), the distance from the contact body 22 to the position of the center of gravity G of the racket 17 is: L= (aR1/ (R1+R2))+b where a,
b becomes a constant.

The weight W of the racket 17 and the distance from the center of gravity can be obtained from the load measured by the load cell 23 and the load measured by the load cell 24.

Next, the operation of this embodiment will be explained.

First, press the power button 38 of the frame 15 to turn on the power 33, then press the zero set button 41 to set the weight display 39 and center of gravity position display 10 to zero.

Thereafter, the racket frame 18 of the racket 17 is placed on the first racket fulcrum 19 in alignment with the center of the scale 26, and the racket frame 18 is placed on the second racket fulcrum 21.
The racket 17 is placed on the first racket fulcrum 19 and the second racket fulcrum 21 by placing the grip 20 of No. 7 and abutting the grip end 20a on the contact body 22.

By placing the racket 17 on the first racket fulcrum 19 and the second racket fulcrum 21, the load cell 23 measures the load on the racket frame 18 side of the racket 17, and at the same time the load cell 24 measures the load on the racket frame 18 side of the racket 17.
The adder 45 of the CPU 44 calculates the weight of the racket 17 from the measured load of the load cell 23 and the measured load of the load cell 24, and the weight display 39
The weight of the racket 17 is displayed.

In addition, the CPU 44 calculates the measured load of the load cell 23, the measured load of the load cell 24, the first racket fulcrum 19 and the second racket fulcrum.
The distance from the contact body 22 to the racket fulcrum 21 and the distance between the contact body 22 and the second racket fulcrum 21 is used to calculate the distance from the contact body 22 to the center of gravity of the racket 17. Displays the location of the center of gravity.

For example, when the racket 17 is placed on the first racket fulcrum 19 and the second racket fulcrum 21, the load cell 2
The measured load R1 of 3 is 191 g, the measured load R2 of the load cell 24 is 241.1 g, and the first rack/soto fulcrum 19
and the second racket fulcrum 21 is 500 mm, and the distance a between the contact body 22 and the second racket fulcrum 21 is 100 mm.
+++l++, the racket weight W calculated by the adder 45 is 432°Jg, the weight display 39 digitally displays the weight of the racket 17 as 432.1, and the CPU 4
The distance from the contact body 22 to the center of gravity of the racket 17 calculated in step 4 is 321.0 m111, and the center of gravity display 40 digitally displays the distance to the center of gravity of the racket 170 as 321.0 by the CPU 44.

Effects of the Invention As described above, according to the device for measuring the center of gravity of a ball hitting tool of the present invention, first. When the ball hitting tool is mounted on the fulcrum and the second fulcrum, and the grip end of the ball hitting tool is brought into contact with the abutting body, the first load measuring means measures the load on the ball hitting part side of the ball hitting tool. At the same time, the second load measuring means measures the load on the grip side of the ball hitting tool, and the weight calculating means calculates the weight of the ball hitting tool from the measured load of the first load measuring means and the measured load of the second load measuring means. Therefore, the weight of the ball hitting tool calculated by the weight calculating means can be displayed on the weight display, and the center of gravity position calculating means can display the measured loads of the first load measuring means and the second load measuring means, the first fulcrum, and the weight of the ball hitting tool calculated by the weight calculating means. Since the distance from the abutting body to the center of gravity of the ball hitting tool is calculated based on the distance to the second fulcrum and the distance between the abutting body and the second fulcrum, the center of gravity position indicator displays the hit ball calculated by the center of gravity position calculation means. The position of the center of gravity of the tool can be displayed, and measurement work can be done quickly and without any hassle, improving work efficiency. The weight and center of gravity position of the tool can be easily read, and the weight and center of gravity of the ball hitting tool can be measured at the same time.

[Brief explanation of the drawing]

Fig. 1 is a front view of a center of gravity measuring device for a ball hitting tool according to an embodiment of the present invention, Fig. 2 is a plan view of Fig. 1, Fig. 3 is a left side view of Fig. 1, and Fig. 4 is a , a right side view of FIG. 1, FIG. 5 is a schematic block diagram of the device for measuring the center of gravity of a ball hitting tool according to the present invention, FIG. 6 is a principle diagram of measuring the center of gravity of a tennis racket, and FIG. FIG. 8 is a schematic diagram showing a swing state. FIG. 8 is a front view of a conventional center of gravity measuring device for a ball hitting tool. 1...tennis racket, 2...grip, 2a...
Grip end, 3... Racket frame, 5...
Base, 6... Support, 7... Rod, 8... Cable, 9
... Contacting body, 10 ... Weight, 11 ... Scale, 15
... Frame body, 16... Scale stand, i 6 a... One end,
16b...Curved end, 1.7...Racket, 18...
Racket frame, 19...first racket fulcrum, 2
0...Grip, 20a...Grip end, 21
...Second racket fulcrum, 22...Abutting body, 23.
...Load cell, 24...Load cell, 25...Support plate, 26...Scale, 27...Support plate, 28...
Base plate, 29...Bracket, 3o...Bracket, 31...Joint body, 32...Ball joint, 33
...Power supply, 34...Load cell amplifier, 35...
Volume mechanism for zero and span, 36... Level,
37... Leg body, 38... Power button, 39... Weight indicator, 4o... Center of gravity position indicator, 41... Zero set button, 42... A/D converter, 43...・・A/
D converter, 44... central processing unit, 45... adder, 46... divider, 47... adder, G... center of gravity, S... fulcrum.

Claims (1)

[Claims] A first fulcrum and a second fulcrum that support the ball hitting tool are respectively disposed at an interval above the scale stand, and a contacting body that abuts a grip end of the ball hitting tool on a side of the second fulcrum. are provided, and first and second load measuring means are provided at the lower part of the scale stand at positions corresponding to the first and second fulcrums, respectively, and the first load measuring means and the second load measuring means are provided. to a weight calculating means that calculates the weight of the ball hitting tool based on the measured loads of the first and second load measuring means, and the measured loads of the first and second load measuring means and the first fulcrum. and the second fulcrum, and the distance between the abutting body and the second fulcrum to calculate the distance from the abutting body to the center of gravity of the ball hitting tool; A device for measuring the center of gravity of a ball hitting tool, characterized in that a calculation means is connected to a weight indicator for displaying the weight of the ball hitting tool, and the center of gravity position calculation means is connected to a center of gravity position indicator for displaying the center of gravity position of the ball hitting tool.