An object of the present invention is to provide a sway amount estimation system that can suppress a reduction in user convenience that would occur if the operation method is switched more than necessary. A sway amount estimation system (300) includes a sensing unit (78), a judgment unit (80), and an estimation unit (79). The estimation unit (79) calculates an estimated value of the amount of sway of an elevator rope due to vibration caused by building sway based on the sway sensed by the sensing unit (78) and an estimation model incorporating the effect of the displacement amplification of the displacement amplifier (7). The judgment unit (80) judges if the estimated value calculated by the estimation unit (79) is greater than a threshold for switching the operation method for the elevator apparatus (11).

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.

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 sway amount estimation system that can suppress a reduction in user convenience that would occur if the operation method is switched more than necessary. A sway amount estimation system (300) includes a sensing unit (78), a judgment unit (80), and an estimation unit (79). The estimation unit (79) calculates an estimated value of the amount of sway of an elevator rope due to vibration caused by building sway based on the sway sensed by the sensing unit (78) and an estimation model incorporating the effect of the displacement amplification of the displacement amplifier (7). The judgment unit (80) judges if the estimated value calculated by the estimation unit (79) is greater than a threshold for switching the operation method for the elevator apparatus (11).

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.

Stall condition in an elevator is potentially dangerous situation if it causes slack to the ropes of the elevator. In such situation a counterweight or elevator car does not move even if the hoisting machine is still operating. This situation may be prevented by stopping the elevator as early as possible after detecting such stall condition. The detection of the stall condition is based on monitoring the torque generated by the hoisting machine of the elevator. When rapid change in the torque is detected a stall condition is suspected. The elevator may be stopped or an alarm may be launched when the stall condition is suspected.

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.

An elevator includes a car, a counterweight, a rotatable drive member, and one or more suspension ropes interconnecting the car and the counterweight and passing over the rotatable drive member. Each of the suspension rope(s) has a first rope section on the first side of the drive member and a second rope section on the second side of the drive member, the first section(s) of the rope(s) being connected to the car to suspend the car. The second section(s) of the rope(s) are connected to the counterweight to suspend the counterweight. Drive machinery controls rotation of the drive member. The elevator includes a rope tension sensor mounted on the counterweight and arranged to sense tension of the second section(s) of the rope(s). The rope(s) include(s) electrically conducting member(s) extending continuously along the length of the rope(s) forming an electrically conducting connection between the car and counterweight. The rope tension sensor is functionally connected with the drive machinery via said electrically conducting connection between the car and counterweight such that reduced rope tension of the second rope section(s) sensed by the rope tension sensor triggers the drive machinery to brake rotation of the drive member and/or to stop rotating the drive member.

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.

An elevator safety control device includes an interface unit that receives a first status signal of a first safety switch, a second status signal of a second safety switch, and a third status signal of a non-safety function unit of an elevator, the second safety switch including a plurality of landing door switches whose status can be determined individually; a safety controller that performs: determining an occurrence of an abnormal event based on the first status signal, the second status signal and the third status signal; determining, after determining the occurrence of the abnormal event, a possibility of a target landing door based on the second status signal; and executing a rescue mode after determining an existence of the possibility, wherein in the rescue mode, the car is caused to travel by gravity and stop at the target landing door by controlling a state of a holding brake device.