Layered Elevator Belt Structure for Lower Sheave Bending Stress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Elevator systems using unidirectional composite load bearing tension members experience high bending stress when the tension member is wrapped around a traction sheave, leading to substantial bending stiffness and potential mechanical issues.
Innovation Solution
A load bearing tension member with a plurality of tension elements offset from the central axis, embedded in a matrix material and encapsulated in a jacket, arranged symmetrically or staggered to reduce bending resistance, and featuring fibers such as carbon, glass, or steel, with a polyurethane, vinylester, or epoxy matrix, and an elastomeric jacket for improved traction and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If unidirectional composite construction is used for load bearing tension members, then light weight and high strength are achieved, but high bending stiffness results which produces substantial bending stress when wrapped around a traction sheave
Solution Approach 1:
The patent applies asymmetry by positioning tension elements offset from the central longitudinal axis of the belt. This asymmetric arrangement creates a neutral axis that passes through the tension elements, allowing the belt to bend around the traction sheave with minimal bending stress while maintaining the high strength benefits of unidirectional composite construction.
Solution Approach 2:
The patent transitions from a conventional symmetric arrangement to an asymmetric offset arrangement in the cross-sectional dimension. By positioning tension elements at an offset distance from the central axis, the design creates a new dimensional configuration that reduces bending stiffness without compromising tensile strength, enabling the belt to flex properly around sheaves.
2Weight of moving object
If unidirectional composite construction is used for load bearing tension members, then light weight is achieved, but high bending stiffness results which produces substantial bending stress
Solution Approach 1:
The asymmetric offset arrangement of tension elements from the central axis reduces the belt's bending stiffness while maintaining its light weight characteristic. This configuration allows the belt to flex around traction sheaves without generating excessive bending stress, preserving the weight advantage of composite materials.
3Stability of the object's composition
If tension elements are arranged symmetrically about the central axis, then balanced load distribution is achieved, but bending resistance increases
Solution Approach 1:
The patent deliberately breaks symmetry by offsetting tension elements from the central axis. This asymmetric positioning reduces bending resistance and allows the belt to flex more easily around sheaves, while the balanced load distribution is maintained through proper spacing and arrangement of the offset elements.
Data Source
AI summary
A load bearing tension member for an elevator system includes a plurality of tension elements arrayed across a tension member width. The tension elements are offset from a tension member central axis, the central axis bisecting a tension member thickness and extending across the tension member width. The tension elements include a plurality of fibers extending along a length of the tension element, and a matrix material in which the plurality of fibers are embedded. A jacket at least partially encapsulates the plurality of tension elements.