The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 13, 1981
Filed:
May. 29, 1979
Donald C Pierce, Novato, CA (US);
Other;
Abstract
A device for describing an ellipse. An enclosed arcuate first slot extends through a cylindrical shell. A path-generating disc fits inside the shell and enables the shell to rotate relatively thereto, and to it is secured a square bottom plate having a plurality of sharp points for centering the device. The disc has a diametrically-extending slot and, perpendicular thereto, a diametrically-extending recess in its upper surface. A cylindrical cam has a path-defining circular projection that rides snugly back and forth in the disc's recess. A cylindrical face of the cam has a radial opening aligned with and leading into another diametrical slot and a tangential opening parallel to that slot. An eccentricity-determining rod fits through the radial opening into the cam's slot, with sliding adjustment; its inner end extends out vertically into the disc's slot, for movement back and forth therealong. A radius rod, having one end secured in the cam's tangential opening, extends out through the shell's slot, and its outer end carries scribing means. A circular top closure for the shell has a slot parallel to the disc's recess and a scale along one edge of the slot for indicating the amount of eccentricity for which the device is set.