Composite Pool Cover Leading Edge for Low-Deflection Wide Spans
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Solution Overview
Problem
Aluminum leading edges for pool and spa covers experience significant sag and downward deflection on pools or spas wider than 20 feet, leading to uneven tension, increased load on motor/drive systems, and aesthetic issues, while also requiring electrical bonding for safety, which increases complexity and cost.
Innovation Solution
A fiber-reinforced polymer composite leading edge with continuous or discontinuous fibers oriented axially and encapsulated in a thermoset or thermoplastic resin matrix, providing reduced deflection, lighter weight, and eliminating the need for electrical bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If aluminum leading edges are used for pools wider than 20 feet, then the leading edge can be made lightweight, but significant sag and downward deflection occur
Solution Approach 1:
The patent applies composite materials by combining aluminum extrusion with high-density polyethylene (HDPE) or other polymer materials to create a hybrid leading edge structure. This composite construction provides the lightweight advantage of aluminum while adding the corrosion resistance and structural stability of polymers, thereby reducing sag and deflection without significantly increasing weight. The composite structure allows for optimized geometry that maintains strength while minimizing deflection under load.
Solution Approach 2:
The patent changes key parameters of the leading edge including increasing the moment of inertia through optimized cross-sectional geometry, adjusting the length-to-diameter ratio, and modifying material properties. These parameter changes are designed to reduce deflection while maintaining acceptable weight levels. The aluminum extrusion is designed with specific dimensional parameters that maximize structural efficiency for wide pool applications.
2Stability of the object's composition
If larger diameter aluminum tubing is used to reduce deflection, then downward deflection decreases, but weight increases and greater drop is required
Solution Approach 1:
The composite construction allows achieving the required moment of inertia for reduced deflection without proportionally increasing weight. The aluminum extrusion provides structural framework while polymer components add stiffness and corrosion resistance. This material combination achieves the deflection performance of larger diameter tubing with lighter overall weight.
Solution Approach 2:
The patent applies local quality by concentrating material where structurally necessary. The aluminum extrusion cross-section is optimized with varying wall thicknesses and geometric features that provide maximum stiffness-to-weight ratio. The composite structure places materials strategically to resist bending moments while minimizing unnecessary weight in less critical areas.
3Strength
If aluminum leading edges are used, then the leading edge can be made structurally strong, but electrical bonding is required increasing complexity
Solution Approach 1:
The use of composite materials including non-conductive polymers (HDPE, PVC, or other plastics) in the leading edge construction reduces or eliminates the electrical conductivity issues that require bonding. The polymer components break the continuous conductive path of aluminum, thereby reducing the need for electrical bonding while maintaining structural strength through the composite action of aluminum and polymer materials.
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 solution achieves minimal deflection (0-0.10 inches per 10 feet) and reduced weight (4-14 ounces per foot), allowing for wider pool coverage with more uniform tension and reduced system load, while eliminating the need for electrical bonding, thus enhancing safety and reducing costs.
Implementation Method 1
a fiber reinforced polymer composite with an axial length from 5 feet to 50 feet, wherein the composite includes at least one of continuous fibers or discontinuous fibers oriented at least partially in the axial direction, and wherein the at least one of continuous fibers or discontinuous fibers are encapsulated by a thermoset or thermoplastic resin matrix
Data Source
AI summary
Provided is a pool and/or spa cover leading edge that provides for minimal deflection across the width of the pool and/or spa, and in particular from 0 to less than or equal to 0.10 inches per 10 feet of width of the pool and/or spa. The pool and/or spa cover leading edge includes at least one fiber reinforced polymer composite with an axial length of from 5 feet to 50 feet with a linear weight per foot from 4 to 14 ounces per foot of axial length and an optional joiner for coupling together two or more composites. The composite includes at least one of continuous fibers or discontinuous fibers oriented at least partially in the axial direction and encapsulated by a thermoset or thermoplastic resin matrix. Also provided are pool and/or spa cover system and a method of reducing the deflection of a leading edge for a pool and/or spa cover.