Composite Elevator Roping for Simultaneous Multi-Car Leveling
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Solution Overview
Problem
Conventional elevator systems with multiple cars in a single hoistway face inefficiencies due to irregular positioning and the need for multiple hoisting machines, which increases costs and complexity, especially at great lifting heights.
Innovation Solution
An elevator system with multiple cars connected by a common suspension roping made of composite material with carbon fibers oriented parallel to the rope's longitudinal direction, reducing rope elongation and dependency on car position, allowing for simultaneous leveling and efficient operation with a single hoisting machine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple independent elevators are placed on top of each other in the same hoistway, then transport capacity is improved, but device complexity and cost increase due to requiring two hoisting machines and two ropings
Solution Approach 1:
The patent merges two separate hoisting systems into a single hoisting machine that controls both elevator cars through a common roping system. The first and second ropes are connected to opposite sides of a single rope wheel, allowing one motor to drive both cars simultaneously, thereby reducing device complexity while maintaining dual-car transport capacity
Solution Approach 2:
The single hoisting machine performs multiple functions by controlling both the first and second elevator cars through the common roping system. The rope wheel and motor assembly serve as a universal hoisting mechanism that can independently position both cars at different landings, eliminating the need for separate dedicated hoisting machines for each car
2Device complexity
If a common roping system is used to suspend multiple elevator cars, then device complexity is reduced, but manufacturing precision deteriorates due to irregular car positioning and difficulty in simultaneous leveling
Solution Approach 1:
The patent applies different properties to different parts of the roping system: the first and second ropes have different lengths to compensate for different car positions, and the ropes are made of elastic material with specific modulus values. This local differentiation allows each rope to be optimized for its specific function, enabling precise positioning of both cars despite using a common hoisting machine
Solution Approach 2:
The patent changes the physical parameters of the roping system by using elastic ropes with specifically selected modulus values (first rope: 40-80 kN/mm, second rope: 20-40 kN/mm). These parameter changes allow the ropes to stretch by controlled amounts under load, compensating for positioning irregularities and enabling both cars to be leveled simultaneously at their respective landings
3Ease of manufacture
If traditional rope materials are used in the suspension roping, then ease of manufacture is maintained, but reliability deteriorates due to great rope elongation and car position dependency
Solution Approach 1:
The patent employs composite rope construction combining steel core elements with polymer outer layers. The first rope contains a steel core surrounded by a polymer layer, while the second rope has a different steel-to-polymer ratio. This composite material approach provides controlled elasticity and reduced elongation compared to traditional homogeneous ropes, improving positioning reliability while remaining manufacturable with conventional rope fabrication techniques
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 system achieves efficient and simultaneous leveling of multiple elevator cars at different heights, reducing operational complexity and costs by minimizing rope elongation and car position dependency, thus optimizing hoistway space usage.
Implementation Method 1
The reinforcing fibers are carbon fibers oriented parallel with the longitudinal direction of the rope in question. The reinforcing fibers are substantially untwisted relative to each other... making the suspension roping very stiff in its axial direction... reducing rope elongation
Data Source
AI summary
The invention relates to an elevator system comprising a first elevator car, a second elevator car, a rotatable rope wheel mounted on a fixed location, and a roping suspending the first and second elevator car on opposite sides of the rope wheel, the roping comprising at least one rope passing over the rope wheel, and connected on the first side of the rope wheel to the first elevator car and on the second side to the second elevator car. Said rope comprises at least one load bearing member oriented parallel with the longitudinal direction of the rope made of composite material comprising reinforcing fibers embedded in polymer matrix, which reinforcing fibers are carbon fibers oriented parallel with the longitudinal direction of the rope.