| 摘要 |
PURPOSE:To easily measure the tension of the gut of a racket, etc., by providing an incidence sensor and a detection sensor for an ultrasonic wave on a wire body at specific distance, and detecting the propagation speed of the ultrasonic wave. CONSTITUTION:Contact terminals 6 and 7 are provided on the wire body 1 such as a gut at the specific distance l. Further, the ultrasonic signal is inputted from an ultrasonic transmitter 4 to a contact terminal 6 through a incidence sensor 2. Further, its receive signal is inputted to an ultrasonic receiver 5 from the contact terminal 7 through a detection sensor 3. A ultrasonic wave transmitter 4, receiver 5, and a speed measuring instrument 10 are connected. Then, the ultrasonic wave is transmitted by the ultrasonic wave transmitter 4 and received by the receiver 5 through the wire body 1. The time from the transmission to the reception is measured to detect the speed of the ultrasonic wave signal. The speed is fast when the tension of the wire body is large and slow when small, so the tension of the wire body is measured easily and precisely with the ultrasonic wave signal. |
