ELLIPSE-GENERATING MECHANISM FOR DRAWING INSTRUMENT FOR ELLIPSES IN SOLID FIGURES

摘要

PURPOSE:To contrive a reduction in cost and a wider range of use for drawing by performing a drawing operation through tracing an elliptic groove with a specified ellipticity directly by a copy interlocking beam and a copying ball, and providing a variety of detachable ellipse-forming disks for various ellipticities as optional component parts. CONSTITUTION:A fixing nut 58 is untightened, and a movable shaft with a circular cross section is moved vertically along a vertical center shaft 1, thereby changing a copying ratio. When an ellipse with a different ellipticity is required, a drawing base part 9 and a copy interlocking beam 46 are moved toward the center shaft 1, whereby a copying ball 51 located in a guide groove 60 of an ellipse-forming disk 47 rides over a ridge of the groove while pushing up a retainer spring 52, and if fitted into a guide groove 61. At the time of changeover from the groove 61 to the groove 60, the drawing base part 9 and the copy interlocking bearm 46 are moved away from the center shaft 1 by pushing outward. The ellipse-forming disk 47 is detachably fitted to a tapered shaft part by a tapered-shaft hole. A variety of ellipse-fornming disks 47 differing in ellipticity are provided as optional component parts, and one of them is used in place of the existing ellipse-forming disk 47, as required.