MRL Elevator 1:1 Roping Layout for Lower Mechanical Complexity

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Solution Overview

Problem

Conventional machine-room-less (MRL) elevator systems with a 2:1 roping arrangement incur significant engineering, manufacturing, and installation costs due to mechanical complexity.

Innovation Solution

A 1:1 roping arrangement using multiple tension members coupled to both the elevator car and counterweights, with synchronized drive assemblies, allowing for a machine-room-less configuration that reduces mechanical complexity and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a 2:1 roping arrangement is used in MRL elevator systems, then the elevator car can be positioned as desired in the hoistway, but the mechanical complexity increases significantly

Engineering Contradiction:

Improveelevator car positioning capabilityVSAvoidmechanical complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system divides the roping function into multiple independent tension members (first tension member and second tension member) instead of using a single complex 2:1 roping arrangement. Each tension member connects the elevator car to counterweights independently, simplifying the mechanical structure while maintaining positioning capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using the conventional 2:1 roping arrangement where the tension member wraps around sheaves, this invention inverts the approach by using a 1:1 roping arrangement where tension members directly connect the elevator car to counterweights, eliminating the need for complex sheave systems

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If a 2:1 roping arrangement is used in MRL elevator systems, then the elevator functionality is achieved, but the engineering and manufacturing costs increase

Engineering Contradiction:

Improveelevator system functionalityVSAvoidengineering and manufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention uses simpler, more cost-effective tension members and counterweights without expensive sheave systems. The design accepts simpler components that can be manufactured more economically, reducing overall system cost while maintaining functionality

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention extracts and eliminates the complex sheave system from the MRL elevator design, retaining only the essential tension members and counterweights needed for functionality, thereby reducing manufacturing complexity and cost

Inventive Principle:

Principle #2Taking out (Extraction)

3Adaptability or versatility

If a 2:1 roping arrangement is used in MRL elevator systems, then the elevator can operate without a machine room, but the installation costs increase

Engineering Contradiction:

Improvemachine-room-less operationVSAvoidinstallation cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The system uses multiple independent tension members that can be installed separately, simplifying the installation process compared to a single complex 2:1 roping system. This segmentation makes the installation more manageable and cost-effective

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention inverts the conventional approach by using direct 1:1 connections instead of wrapped 2:1 arrangements, which simplifies installation procedures and reduces installation costs while maintaining machine-room-less operation capability

Inventive Principle:

Principle #13The other way round (Inversion)

4Device complexity

If multiple tension members are used in a 1:1 roping arrangement, then the mechanical complexity is reduced, but the synchronization requirements increase

Engineering Contradiction:

Improvemechanical complexityVSAvoidsynchronization requirement

Core Design Contradiction:

Device complexityVSDifficulty of detecting and measuring

Solution Approach 1:

The controller merges the control of multiple tension members into a single coordinated system, managing the synchronization of first and second counterweights through unified control logic that simplifies the overall control architecture

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentEP3240752B1Elevator system

Publication Date: 2026.02.11 OTIS ELEVATOR CO

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AI summary

An elevator system (100) includes an elevator car (102). A first drive assembly (160) engages a first tension member (112). The first tension member (112) is coupled to the elevator car (102) and to a first counterweight (104). A second drive assembly (170) engages a second tension member (122). The second tension member (122) is coupled to the elevator car (102) and to a second counterweight (106). The first tension member (112) can be coupled to the elevator car (102) at a first position (110) and the second tension member (122) can be coupled to the elevator car (102) at a second position (120) opposite the first position (110).