Fluid Viscous Damper for Elevator Safety Gear

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Solution Overview

Problem

In high-rise elevators, the inertia of the overspeed governor rope can cause unwanted engagement of the safety gear during quick stops, leading to unnecessary activation, which is difficult to address without redesigning the overspeed governor system to meet safety standards.

Innovation Solution

Implementing fluid viscous damping in the synchronization linkage to dissipate kinetic energy caused by the inertia of the overspeed governor rope, preventing unwanted safety gear tripping by using a fluid viscous damper to dampen the rotary movement of the spindle shaft.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the synchronization lever spring force is increased to prevent unwanted safety gear engagement, then the safety gear engagement reliability is improved, but the overspeed governor rope tensile force requirement increases, leading to heavier governor rope and system redesign

Engineering Contradiction:

Improvesafety gear engagement reliabilityVSAvoidgovernor rope weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

A fluid viscous damper is introduced as an intermediary element between the governor rope and the synchronization linkage. The damper absorbs the inertial forces generated by the governor rope during quick stops, preventing these forces from being transmitted to the synchronization linkage and causing unwanted safety gear engagement. This allows the use of lighter governor rope while maintaining safety gear engagement reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful inertial forces generated by the governor rope during quick stops are converted into useful damping work by the fluid viscous damper. The damper dissipates these inertial forces through fluid viscosity, transforming them from a harmful effect (causing unwanted engagement) into a beneficial effect (controlling and dampening the motion).

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Length of moving object

If the governor rope length is increased for high-rise elevators, then the elevator travel capability is improved, but the governor rope inertia increases, causing unwanted safety gear tripping during quick stops

Engineering Contradiction:

Improvegovernor rope lengthVSAvoidgovernor rope inertia

Core Design Contradiction:

Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The fluid viscous damper serves as a mediator that intercepts the inertial forces generated by the longer governor rope during quick stops. By placing the damper in the synchronization linkage, it prevents these inertial forces from reaching the safety gear, allowing the use of longer governor rope for high-rise elevators without causing unwanted engagement.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The fluid viscous damper provides beforehand cushioning by being pre-installed in the synchronization linkage to absorb and dampen inertial forces before they can cause unwanted safety gear engagement. This protective measure is in place beforehand to handle the increased inertia from longer governor ropes.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Prevents unintended activation of the safety gear during unplanned rapid stops, allowing existing overspeed governor components to be used in high-rise elevators without redesign, ensuring safe operation while adhering to safety standards.

Implementation Method 1

kinetic energy caused by inertia of the overspeed governor rope to the lever arm is dissipated by implementing fluid viscous damping to dampen the rotary movement of the spindle shaft

Methodology Applied

Scientific EffectFluid viscous damping: Viscous Damping

Data Source

PatentUS10669123B2Method for avoiding unwanted safety gear tripping in a safety stopping system of an elevator system, a safety stopping system, and an elevator system

Publication Date: 2020.06.02 KONE OYJ

AI summary

In an elevator system, so as to avoid unwanted safety gear tripping, the kinetic energy, which is caused by inertia of the overspeed governor rope to the lever arm, is dissipated by implementing fluid viscous damping to dampen the rotary movement of the spindle shaft to prevent unwanted safety gear tripping in the event when the upwards movement of the moving mass is decelerated by a machinery brake to perform a quick stop of the moving mass. The fluid viscous damping is effected by a viscous fluid damper which is arranged in the synchronization linkage mounted to the moving mass.