a blackboard

Abstract

A blackboard comprises a fixed blackboard face. An upper sliding seat is fixedly connected to the upper portion of the inner side of the fixed blackboard face. A lower sliding seat is fixedly connected to the lower portion of the inner side of the fixed blackboard face. The upper sliding seat is provided with two guide rails. The guide rails comprise the straight guide rail and the arc-shaped offset guide rail. The two guide rails are each provided with a longitudinal offset mechanism movably. The two longitudinal offset mechanisms are arranged in a spaced mode. An upper support plate is fixedly arranged on the two longitudinal offset mechanisms. A transverse moving mechanism is arranged in each longitudinal offset mechanism movably. The transverse moving mechanisms are connected with the upper sliding seat movably. A guide mechanism is arranged under the lower sliding seat. A lower support plate is arranged under the guide mechanism. A movable blackboard face is arranged between the outer sides of the upper support plate and the lower support plate. The blackboard is reasonable in structure, the side-by-side blackboard faces are in the same plane, and a large gap between the blackboard faces is avoided during usage.

Description

Technical field: [0001] The invention relates to a blackboard. Background technique: [0002] The traditional blackboard is fixed. Usually, students on both sides of the classroom cannot see the content on the far side of the blackboard clearly, which increases the chance of students squinting and affects students' vision. In addition, the existing blackboard is a single board with a limited area. After it is full, it must be erased and then written, but some content still needs to be retained, which has caused inconvenience in teaching. Ordinary blackboards need to be manually erased bit by bit, which is laborious and time-consuming. If projection is required, a roll-up projection screen must be installed above the blackboard, which increases the teaching cost. Because of this, the push-pull blackboard came into being, but it also brought many problems. When the push-pull blackboard is in use, the side-by-side blackboard surfaces are not on the same plane, so there is a v...

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