| 摘要 |
PROBLEM TO BE SOLVED: To provide a new ruler technology for a blackboard that can easily draw a circle with no deviation in a drawn line end without soiling a blackboard surface with chalk powder besides causing no deviation in a drawn line with chalk on the blackboard surface and moreover smoothly removing the ruler from the blackboard surface after drawing a line. SOLUTION: The ruler for the blackboard includes a ruler body 1 having a joint surface part 10 stably joinable to the blackboard surface 6, and a line drawing edge 11 capable of guiding a drawn line with chalk 5. An attracting mechanism 2 having a soft attraction part 20 that can be attracted to the blackboard surface 6 is built in a suitable part of the joint surface part 10 of the ruler body 1, and a detachment operating part 25 is provided for operating to change the attitude of the soft attraction part 20 from its attracted attitude joinable to the blackboard surface 6, to its detached attitude placed in a detached state from the blackboard surface 6. COPYRIGHT: (C)2011,JPO&INPIT |
