| 摘要 |
The present invention provides a blackboard capable of adjusting the height thereof, which can be manufactured in a rapid and convenient way by enabling to control a wire tension. A pulley(40) is rotatably located on a supporting board(51). The supporting board(51) has a long aperture(52) bored in each edge such that a bolt(53) joined to a pole(10) can be passed through. After adjusting the position of the supporting board(51) where pulley(40) is located, the tension adjusting state can be maintained by tightening up the bolt(53). A fix member(55) located on a guider(54) is connected with a adjusting bolt(56) so that the position of the supporting board(51) can be minutely adjusted by adjusting the adjusting bolt(56). Therefore, in the state that the supporting board(51) can be moved freely by disjointing the bolts(53) fixed thereto, the supporting board(51) is guided and moved to the guider(54) by turning the adjusting bolt(56) whereby the wire tension is adjusted.
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