Elevator Tension Member Conversion Coating Adhesion
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Solution Overview
Problem
Conventional load bearing members in elevator systems face issues with insufficient adhesion between the polymer jacket and tension members, leading to overstressing and frictional wear between steel strands, which conventional zinc coatings fail to adequately address.
Innovation Solution
Application of a conversion coating, such as an oxide, phosphate, or chromate, on the tension members, chemically bonded to the steel surface and mechanically bonded to the polymer jacket, enhancing adhesion and reducing friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a zinc coating is applied to steel tension members for corrosion protection, then corrosion resistance is improved, but adhesion between the polymer jacket and tension members deteriorates
Solution Approach 1:
The patent changes the chemical composition and surface properties of the coating by using conversion coatings (phosphate, chromate, or oxide) instead of zinc coating. These conversion coatings create a chemically active surface that enhances adhesion while maintaining corrosion protection, thus resolving the contradiction between corrosion resistance and adhesion strength.
Solution Approach 2:
The patent creates a composite structure with multiple layers: the steel tension member, the conversion coating layer, and the polymer jacket. This composite material system combines the corrosion resistance of the conversion coating with the adhesion properties needed for the polymer jacket bond, simultaneously achieving both improved corrosion resistance and adhesion strength.
2Reliability
If conventional zinc coating is used on steel strands, then corrosion protection is provided, but frictional wear between steel strands is not adequately reduced
Solution Approach 1:
The patent modifies the surface parameters of the steel strands by applying conversion coatings that alter the friction characteristics. The phosphate, chromate, or oxide coatings create a surface layer with reduced friction coefficients, thereby reducing frictional wear between steel strands while maintaining the corrosion protection function.
3Ease of manufacture
If the polymer jacket is applied without adequate surface preparation, then manufacturing simplicity is maintained, but adhesion between jacket and tension members is insufficient
Solution Approach 1:
The patent applies the conversion coating as a preliminary action before the polymer jacket is applied. This pre-treatment modifies the surface properties of the steel tension members to enhance adhesion, ensuring that when the polymer jacket is subsequently applied, optimal bonding occurs without requiring complex surface preparation procedures.
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 conversion coating improves the adhesion between the polymer jacket and tension members, allowing for efficient weight transfer and reducing frictional wear, thereby extending the lifespan of the load bearing members.
Implementation Method 1
the conversion coating includes at least one of an oxide, a phosphate, or a chromate
Implementation Method 2
mechanically bonding the conversion coating to the polymer jacket
Implementation Method 3
reducing frictional wear between steel strands
Data Source
AI summary
A load bearing member (22) useful in an elevator system (10) includes at least one elongated tension member (36), a conversion coating (46) on the elongated tension member (36), and a polymer jacket (34) at least partially surrounding the coated elongated tension member (36). In one example, the conversion coating (46) includes at least one of an oxide, a phosphate, or a chromate.