# US 10,766,742 B2 · Hydraulic elevator safety device, and method for detecting open-door travel abnormality in hydraulic elevator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,766,742 B2 - Document ID: US10766742B2 - Status: Granted - Kind: B2 - Application number: 15/741,369 - Filed: 2015-07-17 - Published: 2018-12-27 - Granted: 2020-09-08 - Earliest claimed: 2015-07-17 - Assignees: Mitsubishi Electric Corporation - Applicants: Mitsubishi Electric Corporation - Inventors: Hirofumi Ikai - Web page: https://patentgrep.com/patent/US10766742B2 ## CPC - B66B 5/028: {Safety devices separate from control system in case of power failure, for hydraulical lifts, e.g. braking the hydraulic jack (B66B5/16 takes precedence)} - B66B 1/04: hydraulic - B66B 5/0031: {for safety reasons} - B66B 9/04: actuated pneumatically or hydraulically (platforms for lifting or lowering through short distances B66F7/00) - 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 A safety device for a hydraulic elevator includes an open-door running prevention unit and a pressure sensor. The open-door running prevention unit includes a memory configured to sequentially store values of the pressure sensor during a period in which the hydraulic elevator is in the open-door state as time-series data. When it is determined that the car speed, detected when the hydraulic elevator is in the open-door state, is equal to or larger than a preset first threshold value, the open-door running prevention unit calculates a differential value between a maximum value and a minimum value of the time-series data stored in the memory in a period of a preset determination time. When the differential value is out of a preset allowable range, the open-door running prevention unit determines that the open-door running abnormality is present, and executes the car braking processing. ## Claims ### Claim 1 A safety device for a hydraulic elevator, comprising: an open-door running prevention means for determining a presence or an absence of an open-door running abnormality based on a detection value of a car speed when the hydraulic elevator is in an open-door state, and for performing car braking processing when it is determined that the open-door running abnormality is present; and a pressure sensor, which is configured to detect a pressure value on a side of a check valve provided in a hydraulic pipe, which is close to a hydraulic tank, wherein the open-door running prevention means comprises a memory that is configured to sequentially store values of the pressure sensor during a period in which the hydraulic elevator is in the open-door state as time-series data, wherein the open-door running prevention means determines whether or not the car speed detected when the hydraulic elevator is in the open-door state is equal to or larger than a preset first threshold value, wherein, when it is determined that the car speed is equal to or larger than the first threshold value, the open-door running prevention means calculates a differential value between a maximum value and a minimum value of the time-series data stored in the memory in a period from a current time at which the car speed becomes equal to or larger than the preset first threshold value to a preset determination time, and wherein, when the differential value is out of a preset allowable range, the open-door running prevention means determines that the open-door running abnormality is present, and executes the car braking processing. ### Claim 2 (depends on 1) A safety device for a hydraulic elevator according to claim 1, wherein the determination time is preset as time twice to four times as long as a period of a natural frequency of a target hydraulic elevator for which the open-door running abnormality is to be detected. ### Claim 3 (depends on 1) A safety device for a hydraulic elevator according to claim 1, wherein the open-door running prevention means further determines whether or not the car speed detected, when the hydraulic elevator is in the open-door state, is equal to or larger than a preset second threshold value, wherein, when it is determined that the car speed is equal to or larger than the second threshold value, the open-door running prevention means determines that the open-door running abnormality is present, and executes the car braking processing, and wherein the first threshold value is preset as a value smaller than the second threshold value. ### Claim 4 A method of detecting an open-door running abnormality for a hydraulic elevator, the method comprising: sequentially storing values of a pressure sensor configured to detect a pressure value on a side of a check value provided in a hydraulic pipe, which is close to a hydraulic tank; determining whether or not a car speed detected, when the hydraulic elevator is in an open-door state, is equal to or larger than a preset first threshold value; calculating, when it is determined that the car speed is equal to or larger than the first threshold value in the second step, a differential value between a maximum value and a minimum value of time-series data stored in a memory in a period from a current time at which the car speed becomes equal to or larger than the first threshold value to a preset determination time, and determining whether or not the differential value is out of a preset allowable range; and determining, when it is determined that the differential value is out of the preset allowable range, that the open-door running abnormality is present, and executing a car braking processing. ### Claim 5 (depends on 1) A safety device for a hydraulic elevator according to claim 1, wherein the open-door running prevention means determines whether or not the car speed detected, when the hydraulic elevator is in the open-door state, is equal to or larger than a preset second threshold value, wherein, when it is determined that the car speed is equal to or larger than the second threshold value, the open-door running prevention means determines that the open-door running abnormality is present, and executes the car braking processing, and wherein the first threshold value is preset as a value smaller than the second threshold value. ### Claim 6 A safety device for a hydraulic elevator, comprising: open-door running prevention circuitry, which is configured to determine presence or absence of an open-door running abnormality based on a detection value of a car speed when the hydraulic elevator is in an open-door state, and to perform car braking processing when it is determined that the open-door running abnormality is present; and a pressure sensor, which is configured to detect a pressure value on a side of a check valve provided in a hydraulic pipe, which is close to a hydraulic tank, wherein the open-door running prevention circuitry comprises a memory that is configured to sequentially store values of the pressure sensor during a period in which the hydraulic elevator is in the open-door state as time-series data, wherein the open-door running prevention circuitry determines whether or not the car speed detected when the hydraulic elevator is in the open-door state is equal to or larger than a preset first threshold value, wherein, when it is determined that the car speed is equal to or larger than the first threshold value, the open-door running prevention circuitry calculates a differential value between a maximum value and a minimum value of the time-series data stored in the memory in a period from a current time at which the car speed becomes equal to or larger than the preset first threshold value to a preset determination time, and wherein, when the differential value is out of a preset allowable range, the open-door finning prevention circuitry determines that the open-door running abnormality is present, and executes the car braking processing. ### Claim 7 (depends on 6) A safety device for a hydraulic elevator according to claim 6, wherein the determination time is preset as time twice to four times as long as a period of a natural frequency of a target hydraulic elevator for which the open-door running abnormality is to be detected. ### Claim 8 (depends on 6) A safety device for a hydraulic elevator according to claim 6, wherein the open-door running prevention circuitry determines whether or not the car speed detected, when the hydraulic elevator is in the open-door state, is equal to or larger than a preset second threshold value, wherein, when it is determined that the car speed is equal to or larger than the second threshold value, the open-door running prevention circuitry determines that the open-door finning abnormality is present, and executes the car braking processing, and wherein the first threshold value is preset as a value smaller than the second threshold value. ### Claim 9 (depends on 6) A safety device for a hydraulic elevator according to claim 6, mwherein the open-door running prevention circuitry determines whether or not the car speed detected, when the hydraulic elevator is in the open-door state, is equal to or larger than a preset second threshold value, wherein, when it is determined that the car speed is equal to or larger than the second threshold value, the open-door running prevention circuitry determines that the open-door running abnormality is present, and executes the car braking processing, and wherein the first threshold value is preset as a value smaller than the second threshold value.