Compasses for whiteboard teaching

Abstract

The invention relates to a pair of compasses for whiteboard teaching, and belongs to the field of teaching tools. The compasses comprises an arm rod (1) and a sleeve rod (2), wherein a whiteboard pen is arranged on the sleeve rod (2), the arm rod (1) is connected with the sleeve rod (2), the arm rod (1) is provided with a cover body (4), the cover body (4) is provided with a magnet (5), the outer wall of the cover body (4) is provided with a protrusion piece (7) which can rotate at any degree, the cover body (4) is connected with one end of the arm rod (1) by the protrusion piece (7), and the magnet (5) is fixedly arranged at the bottom of the cover body (4). The compasses has have the advantages that the expansion angle of the compass can be adjusted by a user, when the magnet is tightly absorbed adsorbed on the whiteboard, and the arm rod can still rotate at any degree, so the compasses is are suitable for the whiteboard; and the length of the arm rod can be adjusted, so the drawing range is expanded, the convenience in teaching is realized, and the practicality is improved.

Description

technical field [0001] The invention relates to a compasses, in particular to a compasses used for whiteboard teaching, and belongs to the field of teaching tools. Background technique [0002] The compass is a drawing tool often used in teaching. It consists of two arms, which are connected to each other. One of the arms is equipped with a drawing pen, and the other arm is a fixed foot. When in use, the With both arms spread apart to the desired width, draw a circle centered on the fixed point of one arm. Can utilize traditional compasses to draw a picture for blackboard, during use, install chalk, and chalk draws circle on blackboard, therefore, this existing teaching compasses all is applicable to blackboard teaching situation basically, for the more commonly used whiteboard now Not applicable. And the arm lever length of traditional compasses is fixed, when drawing the circular arc with bigger radius, can't finish well, therefore, brings unnecessary trouble to teaching...

AI Technical Summary

Problems solved by technology

Can utilize traditional compasses to draw a picture for blackboard, during use, install chalk, and chalk draws circle on blackboard, therefore, this existing teaching compasses all is applicable to blackboard teaching situation basically, for the more commonly used whiteboard now not applicable

Moreover, the length of the arm of the traditional compass is fixed. When drawing an arc with a large radius, it cannot be completed well. Therefore, unnecessary troubles are brought to the teaching.

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