在划线工作中,常碰到圆柱体(或圆筒)同平面(或曲面)相交,需要在相交面上画椭圆的问题。为此,我们自制了曲面椭圆规(见图),画线准确、使用方便。AC和AB是圆规的两长脚,脚间角度β可任意调节,BF、BG是两只小分脚,其角度θ也可调节。E为带画针的圆筒形套,可在长脚AC上滑动和转动,画针ED与AC间夹角γ也可调整。 In the marking work, often encounter the cylinder (or cylinder) intersect with the plane (or surface), the need to draw ellipses on the intersection of the problem. To this end, we made a self-made surface oval rules (see Figure), drawing lines accurate, easy to use. AC and AB are two long legs of the compass, angle β between legs can be adjusted, BF, BG are two small sub-feet, the angle θ can be adjusted. E is a cylindrical sleeve with a drawn needle, which can slide and rotate on the long leg AC, and the angle γ between the drawn needle ED and the AC can also be adjusted.