Thread profile measuring method

Patent metadata

Field	Value
Publication number	US-9395181-B2
Application number	US-201314049335-A
Country	US
Kind code	B2
Filing date	Oct 9, 2013
Priority date	Oct 11, 2012
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

A method includes: performing a scanning measurement of a female thread along first and second axes extending along a center axis of the thread and opposed to each other across the center axis; determining characteristic values of the thread from contour data of the thread obtained through the measurement; obtaining the contour data including first contour data associated with the first axis and second contour data associated with the second axis by performing the measurement; detecting a thread displacement along the center axis between a crest associated with the first axis and a crest associated with the second axis at each of first position and second position on the center axis; calculating inclination and deviation of the first and second axes from the thread displacements detected at the first and second positions; and adjusting an attitude of the thread for the measurement to eliminate the inclination and deviation.

First claim

What is claimed is:

1. A thread profile measuring method comprising:
scanning a thread along a first axis and a second axis extending along a center axis of the thread to obtain contour data of the thread, the first axis and second axis being opposed to each other across the center axis;
detecting a first distance of thread displacement along the center axis between a thread crest on the first axis and a thread root on the second axis at a first position on the center axis;
detecting a second distance of thread displacement along the center axis between a thread crest on the first axis and a thread root on the second axis at a second position on the center axis;
calculating an inclination and a deviation of the first axis and the second axis from the first distance of thread displacement detected at the first position and the second distance of thread displacement detected at the second position; and
adjusting an attitude of the thread to eliminate the inclination and the deviation.

2. The thread profile measuring method according to claim 1 , further comprising trigonometrically calculating the inclination and the deviation using the first and second distances of thread displacements, a distance between the first position and the second position, and a thread lead angle of the thread profile.

3. The thread profile measuring method according to claim 1 , further comprising repeating the scanning the thread to obtain the contour data, the calculating of the inclination and the deviation and the adjusting of the attitude of the thread profile until any one of whether or not an accuracy of the inclination and the deviation reaches a predetermined level, whether or not the obtaining, the calculating and the adjusting are repeated for a predetermined number of times or more, and whether or not an operator requests termination.

4. The thread profile measuring method according to claim 1 , wherein
the scanning measurement is performed on the thread profile using a profile measuring instrument comprising a swingable arm,
the arm comprises a pair of styluses provided on opposite sides in a swinging direction, and
the profile measuring instrument is adapted to perform the scanning measurement along the first axis and the second axis with the styluses.

Assignees

• Mitutoyo Corp

Inventors

• Omori Yoshiyuki

Classifications

• G01B5/204 Primary

  of screw-threads · CPC title

• G01B21/20 Primary

  for measuring contours or curvatures, e.g. determining profile · CPC title