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US 4,462,134 AGranted
Blackboard eraser
OwnerJeng-Lin Wanginventor
Life of this patent
Estimating the term…
Abstract
A blackboard eraser comprising a base, an uppermost cover mounted on the base, two erasing rollers pivotedly mounted within the base, a controller and two scrapers wherein the controller normally engages with the rollers for erasing use and may be depressed to release the rollers for their free rotation to contact the scrapers formed atop the rollers so as to scrape the dust accumulated on roller into a storing chamber spaced between the base and the uppermost cover for final disposal of dust.
Claims5
A blackboard eraser comprising:
- a base;
- an uppermost cover mounted on said base and forming a storing chamber for accumulating dust therein, which is spaced between said uppermost cover and said base;
- two erasing rollers each rotatably mounted within said base;
- a controller normally engaging with said rollers during erasing operation to prevent rotation or for releasing said rollers for their free rotation for dust removal;
- and two dust scrapers respectively fixed on said base, each resiliently contacting the upper perimeter of each roller.
2 more elements
Dependencies are inferred from the claim text.