Elevator Machine Assembly Overlapping Guide Rails

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Solution Overview

Problem

Machine roomless elevator systems face challenges in accessing the machine assembly for maintenance due to space constraints and code requirements, necessitating a solution to reduce hoistway dimensions while ensuring mechanic access.

Innovation Solution

The machine assembly is positioned within the hoistway in an overlapping configuration with car guide rails, reducing the overall width of the elevator system and allowing access from inside the elevator car, with modifications to the traction sheave and guide rails to accommodate this configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the machine assembly is positioned above the roof of the elevator car to maximize hoistway space, then the area available for counterweight is maximized, but access for maintenance becomes difficult requiring mechanics to stand on the car roof or use ladders

Engineering Contradiction:
Improvehoistway space for counterweightVSAvoidaccess for maintenance
Core Design Contradiction:
Area of stationary objectVSEase of operation

Solution Approach 1:

The machine assembly is repositioned from a horizontal arrangement (above the car) to a vertical arrangement (hanging from the hoistway ceiling), utilizing the vertical dimension to resolve the conflict between space utilization and maintenance accessibility

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

A platform is introduced as an intermediary element that provides safe access for mechanics to reach the machine assembly, eliminating the need to stand on the car roof or use ladders while maintaining compact hoistway dimensions

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If elevator codes require increased clearance at the top of the hoistway, then safety clearance is improved, but the overall hoistway dimensions must be increased

Engineering Contradiction:
Improvesafety clearanceVSAvoidhoistway dimensions
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The machine assembly is repositioned vertically within the existing horizontal footprint of the hoistway, allowing safety clearances to be provided in the vertical dimension without increasing the horizontal dimensions of the hoistway

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of repair

If the machine assembly is repositioned within the hoistway to allow access from inside the car, then maintenance accessibility is improved, but the configuration becomes more complex requiring modifications to traction sheave and guide rails

Engineering Contradiction:
Improvemaintenance accessibilityVSAvoidconfiguration complexity
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The guide rails are designed to serve dual functions: guiding the car and providing structural support for the repositioned machine assembly, reducing the need for additional specialized components despite the configuration change

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3283425B1Elevator system
Publication Date: 2020.08.19 OTIS ELEVATOR CO
  • EP3283425B1 patent drawingFigure 1
  • EP3283425B1 patent drawingFigure 2
  • EP3283425B1 patent drawingFigure 3

AI summary

An elevator system is provided including a hoistway having a plurality of landings. An elevator car is configured to move within the hoistway between the plurality of landings. A plurality of guide rails guide movement of the elevator car and a counterweight within the hoistway. Each guide rail includes a base and a blade. A machine assembly is mounted within the hoistway and includes a traction sheave rotatable about an axis. The traction sheave is configured to drive movement of the elevator car between the plurality of landings. At least one of the plurality of guide rails is arranged in an overlapping configuration with the machine assembly such that a plane defined by the base of the guide rail is parallel to the axis and intersects a portion of the traction sheave.