| 摘要 |
PROBLEM TO BE SOLVED: To provide a blackboard wiper cover which rapidly recovers a large amount of scattered chalk dust generated when a picture or a character drawn on the blackboard using a chalk is erased with a wiper, and also eliminates the harmful effect of the chalk dust upon health and environments when it is inhaled or sticks to the body. SOLUTION: This blackboard wiper cover is a thin and lightweight metallic or resin cover which can be easily fitted to and removed from a conventional blackboard wiper. The cover has 60 to 100 holes with a diameter of 2 mm perforated so as to ensure a smooth air circulation. In addition, chalk dust is accumulated and recovered, using a projecting part and a dust trap formed on the inner face of the cover and the cover is connected to an outside suction machine, so that the rapid recovery of a large amount of the chalk dust is achieved under the described cover structure.
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