Elevator Suspension Body Segmented Load-Bearing Layer

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Solution Overview

Problem

Existing elevator ropes with reinforcement fibers are inflexible, leading to increased internal stress and the risk of breakage when bent around a driving sheave, necessitating a larger sheave diameter to prevent breakage.

Innovation Solution

A suspension body with a load-bearing layer divided into segment layers and intermediate layers, where the intermediate layers have lower shear rigidity than the segment layers, allowing for improved bendability and stress relief when bent, thereby reducing the stress on the load-bearing layer and enabling a smaller sheave diameter.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If reinforcement fibers are evenly dispersed in polymer matrix and arranged in parallel, then breaking strength per weight is improved, but flexibility deteriorates

Engineering Contradiction:
Improvebreaking strengthVSAvoidflexibility
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The load-bearing layer is divided into multiple segment layers arranged in the thickness direction. Each segment layer contains reinforcement fibers arranged in parallel, but the segmentation allows relative movement between layers during bending, thereby maintaining high breaking strength while improving flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a two-dimensional arrangement (fibers in a single plane) to a three-dimensional segmented structure. By stacking multiple segment layers in the thickness direction with intermediate layers between them, the structure gains flexibility in the bending direction while preserving strength through the distributed fiber arrangement across multiple layers.

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

2Ease of operation

If rope is bent around driving sheave, then elevator operation is enabled, but internal stress increases causing breakage risk

Engineering Contradiction:
ImprovebendabilityVSAvoidbreakage resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

Dividing the load-bearing layer into multiple segment layers allows each layer to accommodate bending stress independently. The intermediate layers between segment layers act as stress-relief zones, enabling the rope to bend around the driving sheave without concentrating excessive stress that would lead to breakage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the structural parameters of the rope by introducing segmented layers with different material properties. The intermediate layers have different mechanical properties compared to the segment layers, creating a gradient structure that optimizes stress distribution during bending operations.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If rope flexibility is improved by segmentation, then bending stress is reduced, but device complexity increases

Engineering Contradiction:
ImproveflexibilityVSAvoidstructural complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

While segmentation does increase structural complexity, it is the most effective way to achieve the desired flexibility improvement. The segmented structure with intermediate layers provides a systematic approach to managing bending stresses that cannot be achieved with simpler homogeneous structures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses composite material structure where segment layers and intermediate layers are made of different materials with complementary properties. This composite approach allows each layer to contribute specific functions, achieving flexibility improvement while managing the overall structural complexity through functional specialization.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3617121B1Elevator, suspension body therefor, and production method for suspension body
Publication Date: 2025.01.15 MITSUBISHI ELECTRIC CORP
  • EP3617121B1 patent drawingFigure 1
  • EP3617121B1 patent drawingFigure 2~4
  • EP3617121B1 patent drawingFigure 5

AI summary

A suspension body (7) for an elevator includes a core (21) having a belt-like shape, and a covering layer (22) covering at least a part of an outer periphery of the core (21). The core (21) includes a load bearing layer (23). The load bearing layer (23) is formed of an impregnation resin and a plurality of high-strength fibers (34). Further, the load bearing layer (23) is divided into a plurality of segment layers arranged apart from each other in a thickness direction of the core. An intermediate layer made of a material different from that for the load bearing layer (23) is interposed between the segment layers adjacent to each other in the thickness direction of the core (21).