Surface curvature measurement tool
A device for measuring the radius of curvature of a surface comprises a main body that is held above the surface being measured; and a non-contact sensor mounted to the main body that measures a distance between the surface being measured and the sensor, the device calculating the radius of curvature of the surface based on the measured distance. The device can further include a display mounted to the main body that displays the calculated radius of curvature. The non-contact sensor can be, for example, an acoustical distance sensor or an optical distance sensor. In one embodiment, the device includes two arms extending from the main body of the device and being substantially symmetric about the non-contact sensor, the arms terminating in contact points that make contact with the surface being measured. In another embodiment, the device includes three non-contact sensors mounted to the main body, each measuring a distance between the surface being measured and the respective sensor, the device calculating the radius of curvature of the surface based on the measured distances. In yet another aspect of the invention, a radius of curvature measuring device has an adjustable arm that is movable with respect to a main body and a linear encoder associated with the adjustable arm for measuring a distance from the surface of interest.
1. A device for measuring the radius of curvature of a surface, comprising:
a main body that is held above the surface being measured;
three non-contact sensors mounted to the main body, the three non-contact sensors comprising a central non-contact sensor mounted to the main body and a pair of peripheral non-contact sensors mounted to the main body at an angle, a, relative to the central sensor and symmetric with respect to the main sensor, the central sensor configured to measure distinct, independent distance d 2 of a line extending from point (x 2 ,y 2 ) on the surface being measured to point P and the pair of peripheral non-contact sensors configured to measure distinct, independent distances (d 1 and d 3 ) of two lines extending from respective points [(x 1 , y 1 ), (x 3 , y 3 )] on the surface being measured and converging at point P; and
a computer processor mounted to the main body and configured to receive the distinct, independent measured distances d 1 , d 2 and d 3 and to calculate a radius of curvature of the surface based on the distinct, independent measured distances d 1 , d 2 , and d 3 .
2. The device of claim 1 , further comprising:
a display mounted to the main body that displays the calculated radius of curvature.
3. The device of claim 1 , wherein the three non-contact sensors comprise acoustical distance sensors.
4. The device of claim 1 , wherein the three non-contact sensors comprise optical distance sensors.
5. The device of claim 4 , wherein the optical sensors use at least one of time-of-flight, triangulation, modulated beam, and interferometery methods for measuring distance.
6. The device of claim 1 , further comprising transmitters for transmitting visible light beams from points near or at the non-contact sensors to provide visual confirmation of the surface being measured.
7. The device of claim 1 , wherein the values of distances d 1 , d 2 , d 3 and angle, a, are known or measured values, and the location of points (x 1 , y 1 )(x 2 , y 2 ), (x 3 , y 3 ) are determined relative to P, and the radius of curvature of the surface is calculated from the equation of the circle containing points (x 1 , y 1 ), (x 2 , y 2 ) and (x 3 , y 3 ).
8. A method for measuring the radius of curvature of a surface, comprising:
positioning a main body having three non-contact sensors above the surface being measured, the three non-contact sensors comprising a central non-contact sensor mounted to the main body and a pair of peripheral non-contact sensors mounted to the main body at an angle, a, relative to the central sensor and symmetric with respect to the main sensor;
using the central non-contact sensor, measuring distinct, independent distance d 2 of a line extending from point (x 2 , y 2 ) on the surface being measured to point P;
using the pair of peripheral non-contact sensors, measuring distinct, independent distances (d 1 and d 3 ) of two lines extending from respective points [(x 1 , y 1 ), (x 3 , y 3 )] on the surface being measured and converging at point P; and
calculating a radius of curvature of the surface based on the distinct, independent measured distances d 1 , d 2 , and d 3 .
9. The method of claim 8 , further comprising:
displaying the calculated radius of curvature on a display mounted to the main body.
10. The method of claim 8 , wherein the three non-contact sensors comprise acoustical distance sensors.
11. The method of claim 8 , wherein the three non-contact sensors comprise optical distance sensors.
12. The method of claim 11 , wherein the optical sensors use at least one of time-of-flight, triangulation, modulated beam, and interferometery methods for measuring distance.
13. The method of claim 8 , further comprising:
transmitting visible light beams from points near or at the non-contact sensors to provide visual confirmation of the surface being measured.