| 摘要 |
An eraser of a blackboard for preventing scattering of chalk dust is provided to prevent the chalk dust from being scattered in the air and to collect and discharge the chalk dust outside. The eraser installed at a settling bar formed at the lower end of a blackboard to prevent scattering of chalk dust is composed of a connecting pipe(20) of a lower case(19) linked to a dust suction device having a suction motor, through suction pipes(15a,15b), and an upper case(24) combined to the lower case, attached with a cloth(29) for wiping off the blackboard, and formed with a suction hole(26) sucking the air containing dust. A reinforcing plate is installed at the inside of the upper case. A part of the upper case where the cloth is attached is formed in a semi-circle. The suction pipe connected to the dust suction device is branched off into two suction pipes having valves in the middle. The connecting pipes of the lower case are connected to the ends of the suction pipes. The suction motor of the dust suction device interlocks with a switch turned on or off as the eraser is placed on the setting bar of the blackboard.
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