# US 9,752,860 B2 · System and method for gear measurement > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,752,860 B2 - Document ID: US9752860B2 - Status: Granted - Kind: B2 - Application number: 14/798,955 - Filed: 2015-07-14 - Published: 2017-01-19 - Granted: 2017-09-05 - Earliest claimed: 2015-07-14 - Assignees: Caterpillar Inc. - Applicants: Caterpillar Inc. - Inventors: Richard G. Marsh - Web page: https://patentgrep.com/patent/US9752860B2 ## CPC - G01B 5/202: {of gears} - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS ## Abstract A system and method is provided for measuring a physical parameter of a gear. The system and method includes moving a contact probe into a start position on the pitch circle of the gear in a gap between adjacent teeth. The contact probe is moved in a path substantially along the pitch circle of the gear until the contact probe contacts the flank of one of the adjacent gear teeth at a contact point. Spatial coordinates of the contact point are determined. A measurement of a physical parameter of the gear is determined based on the spatial coordinates of the contact point. ## Claims ### Claim 1 A method for measuring a physical parameter of a gear, the gear having a pitch circle and a plurality of teeth with adjacent teeth separated by a gap that is defined by a flank of each of the adjacent teeth, the method comprising: moving a contact probe into a start position on the pitch circle of the gear in a gap between adjacent teeth; moving the contact probe in a path substantially along the pitch circle of the gear until the contact probe contacts the flank of one of the adjacent gear teeth at a contact point; determining spatial coordinates of the contact point; and determining a measurement of a physical parameter of the gear based on the spatial coordinates of the contact point. ### Claim 2 (depends on 1) The method of claim 1 wherein the step of moving the contact probe into the start position involves determining an approach vector for moving the contact probe from a current position to the start position. ### Claim 3 (depends on 1) The method of claim 1 wherein the step of moving the contact probe in the path along pitch circle involves dividing a segment of the pitch circle into a plurality of circumferentially spaced points and determining vectors that define paths of travel for the contact probe between those points that substantially match the pitch circle. ### Claim 4 (depends on 1) The method of claim 1 further including the step of determining the pitch circle of the gear. ### Claim 5 (depends on 1) The method of claim 1 further including the step of displaying the measurement of the physical parameter. ### Claim 6 (depends on 1) The method of claim 1 wherein the measurement of the physical parameter is a tooth profile. ### Claim 7 (depends on 1) The method of claim 1 wherein the measurement of the physical parameter is a tooth thickness. ### Claim 8 (depends on 1) The method of claim 1 wherein the measurement of the physical parameter is tooth spacing. ### Claim 9 (depends on 1) The method of claim 1 wherein the measurement of the physical parameter is a tooth profile. ### Claim 10 (depends on 1) The method of claim 1 wherein the measurement of the physical parameter is a tooth thickness. ### Claim 11 (depends on 1) The method of claim 1 wherein the measurement of the physical parameter is tooth spacing. ### Claim 12 A gear measurement system for measuring a physical parameter of a gear, the gear having a pitch circle and a plurality of teeth with adjacent teeth separated by a gap that is defined by a flank of each of the adjacent teeth, the gear measurement system comprising: a contact probe configured to produce a signal when the contact probe contacts the flank of a gear tooth; a probe positioning system configured to move the contact probe in at least two-dimensional space; and a controller in communication with the contact probe and the probe positioning system and being configured to direct movement of the contact probe by the probe positioning system, the controller being configured to: direct the probe positioning system to move the contact probe to a starting position on the pitch circle in a gap between adjacent teeth; move the contact probe in a path substantially along the pitch circle until the contact probe contacts the flank of one of the adjacent gear teeth at a contact point; determine spatial coordinates of the contact point; and determine a measurement of a physical parameter of the gear based on the spatial coordinates of the contact point. ### Claim 13 (depends on 12) The gear measurement system of claim 12 wherein the controller determines an approach vector for moving the contact probe from a current position to the start position. ### Claim 14 (depends on 12) The gear measurement system of claim 12 wherein the controller determines the path along pitch circle by dividing a segment of the pitch circle into a plurality of circumferentially spaced points and determining vectors that define paths of travel for the contact probe between those points that substantially match the pitch circle. ### Claim 15 (depends on 12) The gear measurement system of claim 12 further including an input device in communication with the controller and configured for inputting information relating to the pitch circle of the gear. ### Claim 16 (depends on 12) The gear measurement system of claim 12 further including a display in communication with the controller and configured to display the measurement of the physical parameter. ### Claim 17 (depends on 12) The gear measurement system of claim 12 wherein the measurement of the physical parameter is a tooth profile. ### Claim 18 (depends on 12) The gear measurement system of claim 12 wherein the measurement of the physical parameter is a tooth thickness. ### Claim 19 (depends on 12) The gear measurement system of claim 12 wherein the measurement of the physical parameter is tooth spacing. ### Claim 20 A method for measuring a physical parameter of a gear, the gear having a pitch circle and a plurality of teeth with adjacent teeth separated by a gap that is defined by a flank of each of the adjacent teeth, the method comprising: determining an approach vector for moving the contact probe from a current position to a start position on the pitch circle of the gear in a gap between adjacent teeth; moving the contact probe to the start position using the approach vector; determining a path from the start position along the pitch circle by dividing a segment of the pitch circle into a plurality of circumferentially spaced points and determining vectors that define paths of travel for the contact probe between those points that substantially match the pitch circle moving the contact probe along the path until the contact probe contacts the flank of one of the adjacent gear teeth at a contact point; determining spatial coordinates of the contact point; and determining a measurement of a physical parameter of the gear based on the spatial coordinates of the contact point.