Spaced-Layer Synthetic Rope Friction Control
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Solution Overview
Problem
Existing synthetic fiber ropes for elevator systems face challenges in efficiently transmitting traction forces between strand layers due to low coefficients of friction, leading to potential wear and displacement issues, which affect the service life and safety of the elevator installation.
Innovation Solution
A synthetic fiber rope design with strands arranged in multiple layers, where each layer is spaced apart in the circumferential direction without embedding, allowing for radial movement and increased friction coefficients through the use of dry lubricants like Teflon powder, ensuring effective traction force transmission and reduced wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If strands are embedded in each other to prevent displacement, then structural stability is improved, but friction coefficient increases leading to increased wear
Solution Approach 1:
The patent introduces an intermediary substance (dry lubricant such as Teflon powder) between the strands to reduce friction and wear while maintaining structural stability. The lubricant acts as a mediator that allows strands to maintain their position without excessive friction that would cause wear.
2Object-generated harmful factors
If dry lubricant is applied to reduce friction and wear, then wear is reduced, but coefficient of friction decreases potentially causing strand displacement
Solution Approach 1:
The patent optimizes the friction coefficient to a specific range (0.2 to 0.45) by controlling the amount and type of dry lubricant applied. This parameter optimization ensures that friction is reduced enough to minimize wear but remains sufficient to prevent strand displacement.
3Reliability
If strands are spaced apart without embedding, then radial movement is enabled improving traction force transmission, but structural compactness decreases
Solution Approach 1:
The patent enables dynamic radial movement of strands by spacing them apart without embedding, allowing the strand structure to adapt and move radially during operation to improve traction force transmission while maintaining operational reliability.
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 design enhances the service life and safety of the synthetic fiber rope by maintaining consistent traction force transmission and minimizing wear, as the friction coefficients are optimized within the ideal range of 0.2 to 0.45, ensuring reliable operation under bending cycles.
Implementation Method 1
The coefficients of friction between the inner and outer strands are fairly low, especially with lubricated strands. Even with non-lubricated strands, the coefficients of friction are in a relatively low range from p = 0.2 to 0.45. This range must not be undershot so that the shearing forces can be transmitted permanently without any lasting change in the rope structure.
Implementation Method 2
The power transmission between the outer and inner strands occurs via frictional forces. In order to be able to transfer frictional forces, a normal force and a certain level of friction are required. The necessary normal force is applied by adjusting the radial contact pressure of the outer strands on the inner strands.
Data Source
Figure 1~2
Figure 3
AI summary
An outer strand layer (2) has strands (7) mutually spaced apart in a circumferential direction. The inner strand layers (3,4) have strands (8-10) mutually spaced apart in the circumferential direction. The strands of the outer strand layer can freely move in radial direction in a direction of a center of the cable and exert a radial pressure on the strands of the inner strand layer. The radial pressure increases in an inwardly direction. Independent claims are also included for the following: (1) a supporting and driving unit; and (2) a method of producing a synthetic fiber cable.