Drawing ruler for geographic subject

• Main Authors: ZHANG LIYUN, XU NING, QIAO LIANG, DI MINGHUI, ZHANG WEI
• Format: Patent
• Language: Chinese; English
• Published: 27.09.2019
• Subjects: ACCESSORIES FOR WRITING OR DRAWING; ARTICLES FOR WRITING OR DRAWING UPON; BUREAU ACCESSORIES; PERFORMING OPERATIONS; TRANSPORTING; WRITING OR DRAWING IMPLEMENTS

The invention discloses a drawing ruler for a geographic subject. The drawing ruler for the geographic subject comprises a first structure and a second structure. The first structure comprises an upper structure, a lower structure and a fixing block, wherein the lateral side of the fixing block is in sliding connection with one side of the upper structure and one side of the lower structure. The second structure is pulled out from the upper structure and the lower structure so as to be capable of being extended. After the second structure is extended, a driven piston is driven by a driving piston to move, so that an air bag ball is inserted into a ball cavity of the upper structure and a ball cavity of the lower structure for fixing. When a circle needs to be drawn, a threaded column and a threaded hole are fixed by rotating a clamping device, and meanwhile, an elliptical disc pushes fixing rods in fixing devices on the upper side and lower side to be inserted into a limiting hole, so that the distance betwee