| 摘要 |
An automatic erasing device is used for erasing chalk marks on a writing board, and includes an erasing mechanism having an elongate housing adapted to be disposed frontwardly of and slidable relative to the writing board between left and right end portions along a longitudinal axis. The elongate housing extends in a transverse axis relative to the longitudinal axis, and has a rear wall formed with an elongate rear opening to confront the writing board. Upper and lower axles are journalled in the elongate housing parallel to the longitudinal axis. A transmitting belt is trained on the upper and lower axles under tension for movement along a rear route proximate to and in alignment with the elongate rear opening, and along a front route parallel to the rear route distal to the elongate rear opening. Several eraser members are mounted detachably on the transmitting belt. The eraser members, when moving along the rear route, protrude outwardly and rearwardly of the rear wall via the elongate rear opening to abut against the writing board. A driving motor drives the upper and lower axles so as to move the eraser members along the front and rear routes. The elongate housing is further driven to move reciprocally in the longitudinal axis, is biased toward the writing board.
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