Method of determining circularity and mean radius of closed curved surface
AssigneePGL Corporation
InventorsPaul R. Caron, Gilbert Fain, Lee E. Estes
Life of this patent
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Abstract
A device (gage, data station, and software) and method to measure mean radius and deviations from mean radius of nominally cylindrical or conical shapes in a plane perpendicular to the nominal axis of revolution using curvature measurements at uniformly spaced intervals about the circumference is described. The system divides the contour of interest into equal segments and measures the local curvature at each point. The group of measurements combines with a closure constraint to produce a condition of mathematical overcompleteness. This is used to minimize the accumulation of measurement error.
Claims19
A method of determining the shape of a surface surrounding a reference axis which includes:
- (a) establishing a reference plane which plane is perpendicular to the reference axis and which plane extends through the surface, the intersection of the plane with the surface defining a curved path;
- (b) dividing the path into a plurality of contiguous segments with the junction of the adjacent segments defining stations;
- (c) measuring the curvature of each station;
- (d) invoking the closure property of the surface by forcing the mathematical solution to be continuous for a complete revolution as is the physical surface;
- and
- (e) producing a deviation of each of the stations from the nominal shape of interest.
A method of determining the mean radius of a curved surface surrounding a reference axis which includes:
- (a) establishing a reference plane which plane is perpendicular to the reference axis and which plane extends through the surface, the intersection of the plane with the surface defining a curved path;
- (b) dividing the path into a plurality of contiguous segments with the junction of adjacent segments defining stations;
- (c) producing both a deviation of each of the stations from the best fit circle and the mean radius (R) which is the radius of the best fit circle;
- and
- (d) determining the mean radius (R) of said curved surface by evaluating the equation ##EQU20## where G is the girth measurement of said surface along said path.
Dependencies are inferred from the claim text.