Provided is a derailment detection device for a counterweight of an elevator comprising: a wire suspended in parallel with a guide rail for the counterweight; a cylindrical member which has an arm portion connected to the counterweight and allows the wire to pass therethrough in a vertical direction; a detection target connected to a lower end of the wire; a photoelectric sensor which is provided on a fixed surface so as to be opposed to a lower surface of the detection target and measures a distance to the detection target; and a detection circuit electrically connected to the photoelectric sensor. The detection circuit detects that the counterweight runs off the guide rail based on the distance from the photoelectric sensor to the detection target.

The invention concerns a method, system and computer program for monitoring the run of a roping interconnecting a car and a counterweight of an elevator and for detecting an abnormal operation condition during the drive of a traction sheave intending therewith the car and the counterweight to be moved via said roping. Said roping is running on its way from the car to the traction sheave via at least one pulley and on its way from the counterweight to the traction sheave via at least one pulley, wherein the rotation of said at least two pulleys is monitored by sensing their rotation. These rotation data are then analysed in view of a mutual correlation indicating therewith a synchronized run of the roping on either side of the traction sheave, and detecting therewith an abnormal situation when detecting an absence of such correlation.

A counterweight slack detection switch including a body, a first belt guide mounted to the body and configured to engage a first side of a tension member, a second belt guide mounted to the body and configured to engage the first side of the tension member, a lever arm having a first end and a second end, the first end pivotally mounted to the body, a deflectable member biasing the lever arm relative to the body, a third belt guide mounted to the second end of the lever arm and configured to bias the tension member from a tension position to a slack position, and a switch mounted to the body and configured to contact the tension member when the tension member is in at least one of the tension position and the slack position.

The measurement arrangement for measuring the rotation speed of a component of an elevator, escalator, moving walkway or moving ramp comprises an inductive sensor that is arranged stationary in respect of a rotation axis of the component and adjacent to the component or a measurement part that is attached to the component in a rotationally fixed manner, and the component or the measurement part is configured as rotationally unsymmetrical about the rotation axis so that different angular positions of the component about the rotation axis generate different output signals in the inductive sensor.

A control unit is used to perform a method for installing an elevator system including the steps of: using an at least partially installed traveling body as a movable working platform borne by traction means and having an electronic safety brake; creating an operating state of the safety brake using the control unit to control the safety brake, the control unit having an input from a safety sensor, a processing unit and a signal output connected to the safety brake; generating a control signal by the processing unit at the signal output, wherein the control signal controls the safety brake; detecting an unsafe operating state by the safety sensor; controlling the signal output due to a detection of an unsafe operating state by the processing unit so that the safety brake is triggered; and removing the control unit when the installation of the elevator system is complete.

A vibration damping device for reducing vibration of an elevator rope includes a displacement amplifier arranged around a region from a first portion of the elevator rope drawn and a second portion of the elevator rope drawn from an opposite side of one or more sheaves in parallel with the first portion. The displacement amplifier is configured to amplify a displacement of each of the first portion and the second portion of the elevator rope. The device also includes a limiting member that controls displacement amplification performed by the displacement amplifier such that the displacement of the first portion or the second portion amplified by the displacement amplifier does not become greater than a first displacement, which is a displacement of the elevator rope by which the elevator rope is not allowed to return to an equilibrium position of the vibration.

Provided is a control device for an elevator including: a first control unit configured to control a hoisting machine configured to raise and lower a car and a counterweight in a hoistway; and a second control unit configured to obtain a generation torque which is a torque to be generated by the hoisting machine, and to limit the obtained generation torque to be generated by the hoisting machine so that the obtained generation torque is lower than an abnormal torque which is the generation torque generated when, under a state in which a movement of one of elevating bodies which are the car and the counterweight is limited, the other elevating body is wound by the hoisting machine.

Provided is a derailment detection device for a counterweight of an elevator comprising: a wire suspended in parallel with a guide rail for the counterweight; a cylindrical member which has an arm portion connected to the counterweight and allows the wire to pass therethrough in a vertical direction; a detection target connected to a lower end of the wire; a photoelectric sensor which is provided on a fixed surface so as to be opposed to a lower surface of the detection target and measures a distance to the detection target; and a detection circuit electrically connected to the photoelectric sensor. The detection circuit detects that the counterweight runs off the guide rail based on the distance from the photoelectric sensor to the detection target.

An object of the invention is to provide a vibration damping system that can avoid the occurrence of resonance of an elevator rope regardless of the vibration frequency of a vibration source. A vibration damping system (200) includes a displacement amplifier (7), a calculation unit (66), and a displacement amplification control unit (67). The displacement amplifier (7) is arranged along a given position in the longitudinal direction of the elevator rope. The displacement amplifier (7) amplifies a displacement due to vibration of the elevator rope based on a variable amplification factor. The calculation unit (66) calculates the natural frequency of the elevator rope. The displacement amplification control unit (67) controls the displacement amplification of the displacement amplifier (7) based on the natural frequency calculated by the calculation unit (66) and a preset vibration frequency.

An object of the present invention is to provide a vibration damping device including an instability preventing means, for efficiently suppressing amplification of vibration of a long structure, which is mechanically flexible, due to a resonance phenomenon. A vibration damping device (100) for reducing vibration of a long structure (1) includes a displacement amplifier (7) and limiting members (8). The displacement amplifier (7) is arranged along a given position in the longitudinal direction of the structure (1). The displacement amplifier (7) amplifies a displacement of the structure (1). The limiting members (8) control displacement amplification performed by the displacement amplifier (7) such that the displacement of the structure (1) amplified by the displacement amplifier (7) does not become greater than a first displacement, the first displacement being a displacement of the structure (1) by which the structure (1) is not allowed to return to the equilibrium position of the vibration.