# US 12,600,599 B2 · Fault classification in elevator systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,600,599 B2 - Document ID: US12600599B2 - Status: Granted - Kind: B2 - Application number: 17/098,025 - Filed: 2020-11-13 - Published: 2021-12-02 - Granted: 2026-04-14 - Earliest claimed: 2020-05-29 - Assignees: Otis Elevator Company - Applicants: Otis Elevator Company - Inventors: Uwe Schönauer; Prasanna Nagarajan - Web page: https://patentgrep.com/patent/US12600599B2 ## CPC - B66B 5/0031: {for safety reasons} - B66B 5/02: responsive to abnormal operating conditions - B66B 1/30: effective on driving gear {, e.g. acting on power electronics, on inverter or rectifier controlled motor} - B66B 5/0087: {Devices facilitating maintenance, repair or inspection tasks (devices incorporated in the buffer B66B5/288; railings on top of the car B66B11/0226)} - B66B 13/22: Operation of door or gate contacts - B66B: ELEVATORS; ESCALATORS OR MOVING WALKWAYS ({apparatus for raising or lowering persons on theatrical stages or the like A63J5/12} ; funicular railbound systems with rigid ground-supported tracks and cable traction, e.g. cliff railways, B61B9/00; arrangements of ammunition handlers in vessels B63G3/00; hoists, lifts, or conveyors for loading or unloading in general B65G; braking or detent devices controlling normal movements of winding drums or barrels B66D; ship-lifting devices E02C; garages for many vehicles with mechanical means for lifting vehicles E04H6/12; hoists for feeding ammunition or projectiles to launching apparatus or to loading mechanisms F41A9/00) ## Abstract An elevator system (2, 102) includes a drive system (10) including one or more drive components (11, 13) and drive hardware (15) for controlling the supply of power to the one or more drive components (11,13), a safety chain (16) arranged to break and thus interrupt a supply of power to the one or more drive components (11, 13) unless all of one or more safety condition(s) is satisfied; and a control device (12). The control device (12) is arranged to receive drive information from the drive hardware (15) indicative of a drive system fault; to receive safety chain information from the safety chain (16) indicative of a safety chain break; and to detect and classify a fault in the elevator system (2, 102) using the drive information and the safety chain information. ## Claims ### Claim 1 An elevator system (2, 102) comprising: a drive system (10) comprising one or more drive components (11, 13) and drive hardware (15) for controlling the supply of power to the one or more drive components (11, 13); a safety chain (16) arranged to break and thus interrupt the supply of power to the one or more drive components (11, 13), unless all of one or more safety condition(s) is satisfied; and a control device (12) arranged: to receive drive information from the drive hardware (15) indicative of a drive system fault; to receive safety chain information from the safety chain (16) indicative of a safety chain break; and to detect and classify a fault in the elevator system (2, 102) using the drive information and the safety chain information, wherein the safety chain is arranged to break and thus interrupt a supply of power to the one or more drive components (11, 13) on reception of a safety chain break command from the control device (12); wherein the control device (12) is arranged: to issue a safety chain break command to the safety chain (16) on reception of drive information from the drive hardware (15) indicative of a drive system fault; to measure a time delay between issuing the safety chain break command and receiving safety chain information from the safety chain (16) indicative of a safety chain break; to determine if the time delay is less than a minimum expected propagation time; and if the time delay is less than the minimum expected propagation delay, to classify the fault as a safety chain break. ### Claim 2 (depends on 1) The elevator system (2, 102) of claim 1, wherein the safety chain is arranged to break and thus interrupt a supply of power to the one or more drive components (11, 13) on reception of a safety chain break command from the control device (12). ### Claim 3 (depends on 1) The elevator system (2, 102) of claim 1, wherein the control device (12) is arranged, if the time delay is equal to or greater than the minimum expected propagation delay, to classify the fault as a drive system fault. ### Claim 4 (depends on 1) The elevator system (2, 102) of claim 1, wherein the safety chain (16) comprises a plurality of electrical switches (22) connected in series via a conducting path (24) and arranged to carry an electrical safety chain signal to an end of the conducting path (24), wherein each of the switches (22) is arranged to break the safety chain (16) by interrupting the conducting path (24) unless a respective safety condition is satisfied. ### Claim 5 (depends on 4) The elevator system (2, 102) of claim 4, wherein the safety chain (16) comprises a further switch (23) arranged to break the safety chain (16) by interrupting the conducting path (24) on reception of a safety chain break command from the control device (12). ### Claim 6 (depends on 4) The elevator system (2, 102) of claim 4, wherein the control device (12) is connected to the end of the conducting path (24) and is arranged to detect the presence or absence of the electrical safety chain signal at the end of the conducting path (24), wherein the safety chain information received by the control device (12) indicative of a safety chain break comprises the absence of the electrical safety chain signal at the end of the conducting path (24). ### Claim 7 (depends on 6) The elevator system (2, 102) of claim 6, wherein the control device (12) is connected to the conducting path (24) via one or more filters or amplifiers. ### Claim 8 (depends on 4) The elevator system (2, 102) of claim 4, comprising a power supply switch (20) controlled by the electrical safety chain signal and via which the one or more drive components (11, 13) is supplied with power, wherein the power supply switch (20) is arranged to conduct power only when the safety chain signal is present at the end of the conducting path (24). ### Claim 9 (depends on 4) The elevator system (2, 102) of claim 4, wherein the control device (12) is arranged to receive safety chain information comprising a plurality of measurements of one or more properties of the electrical safety chain signal carried by the safety chain (16). ### Claim 10 (depends on 9) The elevator system (2, 102) of claim 9, wherein the safety chain information comprises a plurality of measurements of one or more continuously variable properties of the electrical safety chain signal. ### Claim 11 (depends on 9) The elevator system (2, 102) of claim 9, wherein the control device (12) is arranged to store safety chain information and to classify retroactively a fault based on stored safety chain information. ### Claim 12 (depends on 1) The elevator system (20, 102) of claim 1, wherein the drive information comprises one or more of a power, current or voltage output of the drive hardware (15). ### Claim 13 (depends on 1) The elevator system of claim 1, wherein the control device is configured to: perform a self-test of the safety chain by issuing a test command and monitoring a response; compare the response to a threshold to detect a safety chain break; and adjust the threshold for classifying the safety chain break. ### Claim 14 (depends on 13) The elevator system of claim 13, wherein the threshold comprises a propagation time of the response to the test command.