| 摘要 |
PROBLEM TO BE SOLVED: To provide an elevatable blackboard apparatus which can keep the weight reduced as much as possible, and the manufacturing and construction costs as well, requires no braking operation, and is easy of the elevating operation. SOLUTION: This elevatable blackboard apparatus is constituted in such a manner that a blackboard 1 is hung and held while resisting the gravity by balance springs 20a, 20b and 20c which are attached to a fixing-holding frame 4 for elevatably holding the blackboard 1. At the same time, a geared cable 15 which keeps a steel wire 15b spirally wound around a core wire 15a by a specified pitch is stretched along the elevating path on the blackboard 1 side. A gear element 25 which engages with the geared cable 15 is installed on the fixing-holding frame 4 side, and the engaged geared cable 15 is vertically moved by the rotation-driving of the gear element 25. Thus, the blackboard 1 which is integrated with the geared cable 15 is elevated through the geared cable 15. COPYRIGHT: (C)2008,JPO&INPIT
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