# US 2021/0276823 A1 · Elevator safety systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0276823 A1 - Document ID: US20210276823A1 - Status: Published application - Kind: A1 - Application number: 16/952,410 - Filed: 2020-11-19 - Published: 2021-09-09 - Earliest claimed: 2020-03-09 - Assignees: Otis Elevator Company - Applicants: Otis Elevator Company - Inventors: Helge Krambeck; Peter Herkel - Web page: https://patentgrep.com/patent/US20210276823A1 ## CPC - B66B 5/0031: {for safety reasons} - B66B 1/32: effective on braking devices {, e.g. acting on electrically controlled brakes (brake control H02P, lift brakes per se B66B5/02)} - B66B 1/3492: {Position or motion detectors or driving means for the detector (B66B1/40, B66B1/50 take precedence; length measuring G01B; speed measuring G01P)} - B66B 1/36: Means for stopping the cars, cages, or skips at predetermined levels - B66B 3/002: {Indicators} - B66B 5/02: responsive to abnormal operating conditions - B66B 9/00: Kinds or types of lifts in, or associated with, buildings or other structures (characterised by control systems B66B1/00; apparatus for raising or lowering persons on stages of theatres A63J5/12) - 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 safety system (40) including: a plurality of landing door sensors (26), each landing door sensor (26) being configured to provide a warning signal (52) when a respective landing door (22) is open; at least one position sensor (14) configured to determine a current position (54) of an elevator car (10) moving within a hoistway (2); an elevator brake (7) configured to halt the motion of the elevator car (10); and a controller (8) configured to send an emergency stop signal (58) to the elevator brake (7). The controller (8) is configured to determine whether to send the emergency stop signal (58) based on: a direction of travel of the elevator car (10) with respect to the open landing door (22); a current speed of the elevator car (10); and a distance (D) between the open landing door (22) and the current position of the elevator car (10). ## Claims ### Claim 1 An elevator safety system (40) comprising: a plurality of landing door sensors (26), each landing door sensor (26) being configured to provide a warning signal (52) when a respective landing door (22) is open; at least one sensor (14) configured to determine a current position of an elevator car (10) moving within a hoistway (2); an elevator brake (7) configured to halt the motion of the elevator car (10); a controller (8) configured to send an emergency stop signal (58) to the elevator brake (7); wherein the controller (8) is configured to determine whether to send the emergency stop signal (58) based on: a direction of travel of the elevator car with respect to the open landing door; a current speed of the elevator car (10); and a distance (D) between the open landing door (22) and the current position of the elevator car (10). ### Claim 2 (depends on 1) The elevator safety system (40) of claim 1, wherein the at least one sensor (14) is a position sensor and the controller (8) is configured to determine the current speed of the elevator car (10) by differentiating data from the position sensor (14). ### Claim 3 (depends on 1) The elevator safety system (40) of claim 1, further comprising a second sensor (16) configured to determine the current speed of the elevator car (10). ### Claim 4 (depends on 1) The elevator safety system (40) of claim 1, wherein the controller (8) is configured to determine whether the elevator car (10) is travelling towards or away from the open landing door. ### Claim 5 (depends on 1) The elevator safety system (40) of claim 1, wherein the controller (8) is configured to: determine to send the emergency stop signal (58) when the elevator car (10) is moving towards the open landing door (22) and the elevator car (10) can be safely stopped before or at the open landing door (22). ### Claim 6 (depends on 1) The elevator safety system (40) of claim 1, wherein the controller (8) is configured to: check the data from the landing door sensor (26) at a predetermined time after receipt of the warning signal (52), and send the emergency stop signal (58) only if the landing door (20) is still open. ### Claim 7 (depends on 1) The elevator safety system (40) of claim 1, the controller (8) is further configured to: determine that maintenance is being carried out on the elevator car (10); determine that a landing door (22) close to the elevator car (10) is open; send an emergency stop signal (58) when the current speed of the elevator car (10) is below a predetermined maintenance limit (M), and determine not to send the emergency stop signal (58) when the current speed of the elevator car (10) exceeds the predetermined maintenance limit (M). ### Claim 8 (depends on 1) An elevator system (1) comprising: a hoistway (2) extending between a plurality of landings (20) each having at least one landing door (22); an elevator car (10) configured for moving along the hoistway (2) between the plurality of landings (20); and an elevator safety system (40) according to claim 1. ### Claim 9 A method (100) for operating an elevator safety system (40) comprising: monitoring a current position of an elevator car (10) moving within a hoistway (2); detecting an open landing door (22) within the hoistway (2); determining the distance (D) between the current position of the elevator car (10) and the open landing door (22); determining whether to send an emergency stop signal (58) based on: a direction of travel of the elevator car with respect to the open landing door a current speed of the elevator car (10) and the distance (D) between the open landing door (22) and the current position of the elevator car (10). ### Claim 10 (depends on 9) The method according to claim 9, further comprising a step of determining the current speed of the elevator car (10) by differentiating the data relating to the current position of the elevator car (10). ### Claim 11 (depends on 9) The method according to claim 9, further comprising receiving the current speed from a second sensor (16) provided on the elevator car (10). ### Claim 12 (depends on 9) The method according to claim 9, further comprising: determining if the elevator car (10) is travelling towards or away from the open landing door (22). ### Claim 13 (depends on 9) The method according to claim 9, further comprising: determining to send the emergency stop signal (58) when the elevator car (10) is moving towards the open landing door (22) and the elevator car (10) can be safely stopped before or at the open landing door (22). ### Claim 14 (depends on 9) The method according to claim 9, further comprising: checking the data from the landing door sensor (26) at a predetermined time after receipt of the warning signal (52), and sending the emergency stop signal (58) only if the landing door (20) is still open. ### Claim 15 (depends on 9) The method according to claim 9, further comprising: receiving an input indicating that maintenance is being carried out; determining that a landing door (22) close to the elevator car (10) is open; sending an emergency stop signal (58) when the current speed of the elevator car (10) is below a predetermined maintenance limit (M), and determining not to send the emergency stop signal (58) when the current speed of the elevator car (10) exceeds a predetermined maintenance limit (M).