# US 11,906,397 B2 · Active backlash detection methods and systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,397 B2 - Document ID: US11906397B2 - Status: Granted - Kind: B2 - Application number: 17/701,979 - Filed: 2022-03-23 - Published: 2022-07-07 - Granted: 2024-02-20 - Earliest claimed: 2018-11-21 - Applicants: Martin E. Best - Inventors: Martin E. Best - Web page: https://patentgrep.com/patent/US11906397B2 ## CPC - G01M 99/005: {Testing of complete machines, e.g. washing-machines or mobile phones (testing of machine parts G01M13/00; testing of electric apparatus or components G01R31/50)} - G08B 21/187: {Machine fault alarms} - G01M 13/00: Testing of machine parts - G01P 13/00: Indicating or recording presence, absence, or direction, of movement (electric switches H01H; counting moving objects G06M7/00) - G08B 5/36: using visible light sources - G08B 21/182: {Level alarms, e.g. alarms responsive to variables exceeding a threshold} - H04N 25/75: Circuitry for providing, modifying or processing image signals from the pixel array - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - G08B: SIGNALLING SYSTEMS, e.g. PERSONAL CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS - G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G}) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Methods of and systems for actively detecting an increasing amount of backlash within a machine's mechanical power application to detect, predict, and estimate future mechanical failure. ## Claims ### Claim 1 A system for detecting backlash in a device comprising: a controller; an actuator, wherein the controller measures, records and stores a movement information signal from the actuator; an actuator output element; at least one feedback device that measures, records, and stores movement information of the actuator input element; and at least one movement sensor for detecting movement information of the actuator output element; wherein the system is configured to: determine a calibration movement ratio for a device with respect to at least two parts in the device; collect baseline motion values for the at least two parts in the device during use; measure baseline motion values for the at least two parts in the device during use; collect active motion values for the at least two parts in the device; measure active motion values for the at least two parts in the device; compare the measured baseline motion values to the active motion values; compute a ratio of variance between the measured baseline motion values and the active motion values; and compare the calculated ratio of variance to the calibration movement ratio. ### Claim 2 (depends on 1) The system of claim 1, wherein the feedback device is mounted directly to either the actuator or a device acted upon by the actuator output element. ### Claim 3 (depends on 1) The system of claim 1, wherein at least a first feedback device and at least a second feedback device are employed wherein the first and second feedback devices are mounted independently of one another. ### Claim 4 (depends on 3) The system of claim 3, wherein the first feedback element is mounted on an area of the device that the actuator output element is acting upon and the second feedback element is mounted to a fixed location. ### Claim 5 (depends on 1) The system of claim 1, wherein a ratio of variance between a measured baseline motion value of the actuator output element and an active motion value of the actuator output element is calculated. ### Claim 6 (depends on 1) The system of claim 1, wherein comparing the calculated ratio of variance to the calibration movement ratio occurs continuously. ### Claim 7 (depends on 6) The system of claim 6, wherein the device is in use when the comparing the calculated ratio of variance to the calibration movement ratio occurs. ### Claim 8 (depends on 1) The system of claim 1, wherein when the ratio of variance between the measured baseline motion values and the active motion values increases beyond a set threshold an alert is issued that backlash has occurred. ### Claim 9 (depends on 1) The system of claim 1, wherein no dedicated acceptance test procedure is performed on the device.