HEIGHT ADJUSTABLE APPARATUS IN BLACKBOARD

摘要

The apparatus for controlling the mounting height of blackboard freely, offers widening of usable writing area to the teacher without regard to his height. The apparatus comprises a reduction motor (2) connected with a driving gear (3) and following gears (3a)(3b)(3c)(3d) via chain (4); a switching dog (7a) for selectively switching on/off limit-switches (6)(6') at tensional chain (4), fixed at the black board (10); a sliding body (12) inserted to the inner guide bar (13) of upper bracket (15); a coil spring (16) between the bracket (15) and lower bracket (14) fixed at lower support wood (10') of the blackboard (10).