Elevator Governor Sheave Overlapping Flyweight System

Solution Overview

Problem

Conventional centrifugal governors in elevator systems have dead spaces that can delay the engagement of safety mechanisms during overspeed conditions, leading to potential large elevator car speed increments, which can cause damage and complicate passenger rescue.

Innovation Solution

A governor mechanism with three or more circumferentially overlapping cams and links forming a substantially contiguous circular ring, ensuring immediate engagement of safety sensors upon actuation by reducing dead spaces and maintaining a consistent angular velocity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If two masses are used in a centrifugal governor mechanism, then the mechanism is simpler, but dead spaces are created that delay sensor engagement during overspeed conditions

Engineering Contradiction:

Improvegovernor mechanism complexityVSAvoidsensor engagement reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The governor mechanism is segmented into three or more discrete masses arranged circumferentially around the sheave axis. This segmentation eliminates dead spaces by ensuring continuous coverage around the entire circumference, so that at least one mass is always positioned to engage the sensor immediately upon actuation, regardless of the sheave's rotational position.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each mass is positioned at a specific circumferential location to create localized sensing zones. The masses are distributed around the sheave circumference with their engagement surfaces oriented to contact the sensor at different angular positions, ensuring that the sensor engagement capability is distributed locally around the entire governor assembly.

Inventive Principle:

Principle #3Local quality

2Device complexity

If two masses are used in a centrifugal governor mechanism, then the mechanism requires fewer components, but large elevator car speed increments may occur during overspeed conditions

Engineering Contradiction:

Improvegovernor mechanism complexityVSAvoidelevator car speed control

Core Design Contradiction:

Device complexityVSSpeed

Solution Approach 1:

The governor mechanism is segmented into three or more discrete masses arranged circumferentially around the sheave axis. This segmentation eliminates dead spaces by ensuring continuous coverage around the entire circumference, so that at least one mass is always positioned to engage the sensor immediately upon actuation, regardless of the sheave's rotational position.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The circumferential arrangement of three or more masses creates continuous coverage around the sheave, eliminating gaps in the sensing capability. This ensures that the governor maintains continuous monitoring and immediate response capability throughout all rotational positions, preventing any period where speed control is ineffective.

Inventive Principle:

Principle #20Continuity of useful action

3Ease of manufacture

If two masses are used in a centrifugal governor mechanism, then the mechanism is easier to manufacture, but circumferential dead spaces create delays in safety engagement

Engineering Contradiction:

Improvegovernor mechanism manufacturingVSAvoidsafety engagement time

Core Design Contradiction:

Ease of manufactureVSLoss of time

Solution Approach 1:

The governor mechanism is segmented into three or more discrete masses arranged circumferentially around the sheave axis. This segmentation eliminates dead spaces by ensuring continuous coverage around the entire circumference, so that at least one mass is always positioned to engage the sensor immediately upon actuation, regardless of the sheave's rotational position.

Inventive Principle:

Principle #1Segmentation

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

The solution reduces the risk of large elevator car speed increases during overspeed conditions, enhancing safety by ensuring timely engagement of safety mechanisms and minimizing damage to system components.

Implementation Method 1

The angular velocity of the rotating masses results in a centrifugal force acting to propel the masses away from the sheave axis of rotation

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentUS8931598B2Governor sheave with an overlapping flyweight system

Publication Date: 2015.01.13 OTIS ELEVATOR CO

AI summary

A mechanism for use in an elevator governor assembly including a ground configured to rotate about a ground axis, three or more circumferentially overlapping cams each pivotally attached to the ground at one of three or more ground pivot points radially spaced from the ground axis, and a plurality of links pivotally attaching the three or more cams to one another at a plurality of link pivot points. The circumferentially overlapping cams form a substantially contiguous circular ring about the ground axis. The interconnection of the ground, the cams, and the links form a generally circular mechanism.