| 摘要 |
A baseball batters warm-up device apparatus comprises a ball carried by an arm that is rotateable on a shaft that is supported to a stabelized vertical post, where the arm can be counter rotated by hand or by electric motor, against an elastic energizer line, into an arm holding electro magnetic switch so that when a batter extends his bat into his back-swing, the bat interrupts the beam of a passive infrared sensor, the sensor tripping the switch, & releasing said arm, so the batter can hit the ball and drive the arm back into said holding switch, only to be released again, and hit again, the back-swing, release, and hit sequence providing a rythmic warm-up exercise, and should the batter miss the ball, the arm is stopped and reset by hand, or the batter can step on home plate to actuate the motor to counter rotate the arm into the holding switch.
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