Black board washing and cleaning device with rotating roller - horizontally moving roller traverses black-board surface under constant light pressure

摘要

A wall mounted blackboard washing or cleaning device has sets of toothed racks mounted above and below the blackboard which engage into open wheels mounted on the vertical roller type washing and cleaning device. A spring is used to ensure a constant light contact pressure between the cleaning roller and the blackboard surface cleaning rubber strip. The cleaning roller supplies water to the blackboard and the rubber strip following closely behind it scrapes the excess water off into a trough below the device. On its return to start travel of the board, the spring tension is released thus ensuring that the chalk laden roller does not contact the board surface. Water sprays then clean the roller.