| 摘要 |
PURPOSE: A lifting apparatus of a blackboard is provided to cut down a cost and install conveniently with simple structure, and to fix the blackboard within a stroke of a shock absorber by operating a handle. CONSTITUTION: A blackboard lift is composed of a wall sticking frame(30) fixed in a back face of a blackboard(27) by a bolt; a guiding unit(34) mounted in the wall sticking frame and a board frame(20) not to shake during moving the blackboard up and down; a cylinder(32) fixed vertically in the wall sticking frame; a piston(33) fixed in an upper frame of the blackboard; a thin and long shock absorber(31) having a valve unit to control motion of the piston; and a switch unit opening the valve unit. The blackboard lift moves up and down as strokes of the shock absorber. The shock absorber reduces gravity on the blackboard in guiding the piston in the cylinder, and pushes the blackboard up by resilience in protruding the piston from the cylinder.
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