| 摘要 |
An improved ellipsograph for drawing ellipses, ovoids and circles comprises a frame, a slide block, a disc, a worm wheel, a pivot adjusting block, a stub adjusting block, a motor, a battery holder and a drawing arm. The disc and the worm are screwed together and fitted in the round opening of the slide block. The pivot adjusting block and the stub adjusting block are fitted respectively in the worm wheel and the disc. When the motor is started the screw shaft will cause the worm wheel to turn and the pivot on the pivot adjusting block will circumambulate with the worm wheel. At the same time, the stub on the stub adjusting block fitted in the slot of the frame will roll along the slot due to the tangential force of the worm wheel and cause the slide block with the worm wheel and the disc as a whole to move straightly back and forth. The combination of the circumferential and straight movements of the pivot and the adjustment of the locations of the pivot and the stub will cause the drawing arm fixed to the pivot to draw ellipses, ovoids, and circles on the paper in the place as preset with the positioning plate.
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