Patent ID: 6308426
Filing Date: 2001-10-30
Classification: B43L

Abstract:
An ellipsograph comprising:a base member for defining a distance between two foci of an ellipse;an ellipse drawing frame disposed above the base member such that it can be rotated and linearly reciprocated;a centering section arranged at a lengthwise middle of the base member and along a vertical direction for defining a center of the ellipse and for holding the ellipse drawing frame horizontal;an ellipse deriving thread for determining a total length of three sides of a triangle which is used to draw the ellipse, with one fixed side thereof represented by the distance between the two foci of the ellipse, the ellipse deriving thread being supported by opposite ends of the base member and one end of the ellipse drawing frame thereby to form the triangle, the ellipse being drawn by the ellipse drawing frame while the ellipse drawing frame is rotated and linearly reciprocated; andthe base member including:a guide,a left focus-defining lever, one end of which is linearly movable with respect to the guide,a right focus-defining lever, one end of which is linearly movable with respect to the guide, such that the left and right focus-defining levers can linearly slide relative to the guide to adjust the distance between the two foci of the ellipse, which are represented by opposite ends of the left and right focus-defining levers,a rack formed on each of inner surfaces of the left and right focus-defining levers,a pinion coupled to the centering section at the guide and at a lengthwise middle of the guide such that the pinion meshes with the racks of the left and right focus-defining levers, anda pair of fixing pins which define the distance between the two foci of the ellipse, attached to said opposite ends of the left and right focus-defining levers, respectively.