Patent ID: 7120565
Filing Date: 2006-10-10
Classification: E21B,G06T

Abstract:
1. A method for determining a regular N-polygonal figure for a boring hole having vertexes of N in number, characterized in that: a regular (N−1)-polygonal figure revolves along a circle, which circle is concentric to the center of a regular N-polygonal figure to be determined and has a radius r, and rotates at an angular velocity ω; a contour of the said regular (N−1)-polygonal figure is inscribed on a circle having a radius (N−1) the regular (N−1)-polygonal figure revolves at an angular velocity (1−N)ω; and an area being swept by the said regular (N−1)-polygonal figure defines a regular N-polygonal figure to be determined, which figure is circumscribed on a circle having a radius N(N−2)r; and boring a hole having a shape defined by the the regular N-polygonal figure: the contour of the regular N-polygonal figure can be defined by a function f(θ); the function f(θ) is a one-valued function; the function f(θ) is a periodic function with a period 2π/N; the function f(θ) has one maximum value and one minimum value in one period, the function f(θ) has line symmetry with respect to the center of the minimum point between the two maximum points, in regard to one period from a maximum point to the next maximum point of the function f(θ); and the function f(θ) has a positive curvature or no curvature.