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NTIS 바로가기국가/구분 | United States(US) Patent 등록 |
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국제특허분류(IPC7판) |
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출원번호 | US-0837164 (1992-02-18) |
발명자 / 주소 |
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인용정보 | 피인용 횟수 : 9 인용 특허 : 0 |
A hitting practice device comprises a frame on which is mounted a rotatable arm. The arm is attached to a shaft which is driven by a motor also disposed in the frame. Attached to one end of the arm is a tethered ball such as a baseball or a tennis ball. The motor is drivingly connected to the shaft
An adjustable hitting practice device for use by a hitter, comprising: a frame member having means for adjusting the length of said frame member; a base member removably connected to said frame member for supporting said frame member in a vertical position; a vertically extending, adjustable length
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