EP-4737372-A1 - AN ARRANGEMENT FOR OPERATING AN ELEVATOR

EP4737372A1EP 4737372 A1EP4737372 A1EP 4737372A1EP-4737372-A1

Abstract

Modern elevators with position dependent maximum allowed speed adjust the travelling according to the location in the elevator shaft (100). When the elevator car (102) is closer to the bottom or the top of the elevator shaft (100) the travelling speed is reduced so that in case of accident the impact force to the safety buffers (116) is reduced. The disclosed arrangement comprises a mechanism that limits the travelling speed of the elevator when the position information is not received so that the elevator can still be operated.

Inventors

Jussila, Ari
HIRVONEN, Toni

Assignees

KONE Corporation

Dates

Publication Date: 20260506
Application Date: 20241029

Claims (15)

An elevator comprising: an elevator car connected to a hoisting machine using hoisting ropes; an electronic overspeed governor configured to monitor the movement of the elevator car; at least one position measurement sensor configured to measure the position of the elevator car; wherein the electronic overspeed governor is configured to detect a failure in receiving the position of the elevator car from one or more of the at least one position sensors; and as a response to the detected failure the electronic overspeed governor is configured set a limited maximum allowed speed of the elevator car, wherein the limited maximum allowed speed is based on a predetermined maximum buffer impact speed.
An elevator according to claim 1, wherein the electronic overspeed governor is further configured to limit the speed by instructing the hoisting machine to reduce the speed and/or by activating breaks.
An elevator according to claim 1 or 2, wherein the elevator comprises at least two position measurement sensors.
An elevator according to claim 3, wherein the the electronic overspeed governor is further configured to: set the limited maximum allowed speed as a response to the detected failure in one or more of the at least two position sensors.
An elevator according to claim 3, wherein the the electronic overspeed governor is further configured to: set the limited maximum allowed speed as a response to the detected failure in all of the at least two position sensors.
An elevator according to any of preceding claims 1 - 5, wherein as a response to the detected failure the elevator is further configured to: transmit a request for approving a limited maximum allowed speed of the elevator car to a maintenance person; receive an approval for the transmitted request; and limit the limited maximum allowed speed in accordance with the received approval.
An elevator according to any of preceding claims 1 - 6, wherein the elevator further comprises a controller and the controller comprises two processors and is configured to: receive an input signal at both of the processors; determine if both of the processors indicate automatic operation at the limited maximum allowed speed; and as a response to both of the processors indicating automatic operation at a limited maximum allowed speed, allow the automatic operation at a limited speed in accordance with the limited maximum allowed speed.
An elevator according to any of preceding claims 1 - 7, wherein the electronic overspeed governor is further configured to: transmit a notification of a failure to a maintenance person.
An elevator according to any of preceding claims 1 - 8, wherein the electronic overspeed governor is, when controlling the limited maximum allowed speed, further to: receive the current speed value from two different channels.
An elevator according to any of preceding claims 1 - 9, wherein as a response to the detected failure the electronic overspeed governor is further configured to: stop the elevator car; and continue operating the elevator car in accordance with the limited maximum allowed speed.
A method for controlling an elevator comprising: detecting a failure in receiving the position of the elevator car; and as a response to the detected failure, limiting the maximum allowed speed of the elevator car.
A method according to claim 11, wherein the limited maximum allowed speed is a predetermined maximum buffer impact speed.
A method according to claim 11 or 12, wherein the limiting further comprises: transmitting a request for approving a limited maximum allowed speed of the elevator car to a maintenance person; receiving an approval for the transmitted request; and limiting the maximum allowed speed in accordance with the received approval.
A method according to any of preceding claims 11 - 13, wherein the method further comprises: transmitting a notification of a failure to a maintenance person.
A method according to any of preceding claims 11 - 14, wherein the method further comprises: approving, by a maintenance person, switching back to ordinary operation speed.

Description

DESCRIPTION OF BACKGROUND The following disclosure relates to elevators and particularly to monitoring safety features of an elevator. Modern buildings typically have elevators for moving people and other physical objects. Elevators comprise a hoisting machine to which elevator cars are connected to using hoisting ropes. The hoisting ropes run via a traction sheave of the hoisting machine. The hoisting machine moves the connected elevator car and a counterweight so that passengers and transported objects are moved to a correct destination. The elevator car runs in a shaft that has safety buffers in an elevator shaft pit. The buffers are used to reduce the power of an impact in case that the elevator car for some reason would hit the bottom of the elevator shaft. A separate buffer may be provided for the counterweight. The elevator also comprises hoisting machinery brakes. The hoisting machinery brakes can be opened or closed so that the brake reduces the speed of the elevator car. The movement by the hoisting machine and brakes is controlled by a controller that receives commands, for example, from control panels, calling devices or other systems and peripherals that have been connected to the elevator. During the normal operation elevators may face abnormal situations that without appropriate safety measures could be dangerous to passengers. For this reason, in most countries, the necessary safety measures of elevators are regulated and controlled. It is common that an elevator has separate safety measures that are independent from the normal operation of the elevator. These safety measures commonly comprise one or more independent safety arrangements so that each of the safety arrangements is not disturbed by a failure in another one. One component in safety arrangements is so called overspeed governor. This device monitors the speed of the elevator car and ensures it does not exceed a safe operational limit. Should the elevator begin to descend at an unsafe speed, the overspeed governor activates a safety gear mechanism that brings the elevator car to a controlled stop. Modern elevators may also be equipped with an electronic overspeed monitoring function, which may be position dependent so that the safe operational limit is dependent on the location of the elevator car. This monitoring requires reliable and precise feedback from an elevator car position system during an elevator run. If the position system fails or is missing for some reason, the position dependent overspeed monitoring function is not safe anymore. In that case elevator the service must be interrupted, which will increase elevator downtime. Elevator downtime is particularly undesired in high rises where using stairs is not an option. Similarly, elevator downtime causes inconveniences in lower buildings and limits, for example, access of handicapped people. Thus, there is a continuous need for developing mechanisms that minimize the downtime while maintaining the elevator safe to operate. SUMMARY In the following disclosure an arrangement for setting a speed limit in an elevator having a position dependent travelling speed is disclosed. Modern elevators with position dependent maximum allowed speed adjust the travelling according to the location in the elevator shaft. When the elevator closer to the bottom or the top of the elevator shaft the travelling speed is reduced so that in case of accident the impact force to the safety buffers is reduced. The disclosed arrangement comprises a mechanism that limits the travelling speed of the elevator when the position information is not received so that the elevator can still be operated. In an aspect an elevator is disclosed. The elevator comprises an elevator car connected to a hoisting machine using hoisting ropes; an electronic overspeed governor configured to monitor the movement of the elevator car; at least one position measurement sensor configured to measure the position of the elevator car; wherein the electronic overspeed governor is configured to detect a failure in receiving the position of the elevator car from one or more of the at least one position sensors; and as a response to the detected failure the electronic overspeed governor is configured set a limited maximum allowed speed of the elevator car, wherein the limited maximum allowed speed is based on a predetermined maximum buffer impact speed. The benefit of the arrangement is that the elevator can be maintained in the operation instead of disabling the elevator while waiting for repairing. Setting the maximum allowed speed based on the maximum allowed impact speed keeps the elevator safe even when the position is not known. In an example implementation the electronic overspeed governor is further configured to limit the speed by instructing the hoisting machine to reduce the speed and/or by activating breaks. It is beneficial to instruct the hoisting machine and/or brakes to reduce the speed of the elevator car so that the