Overhead Bi-Fold Door Polymer Cylindroid Lifting Mechanism
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Solution Overview
Problem
Conventional overhead bi-fold doors using wire cables for lifting mechanisms face issues with wear, corrosion, and frequent adjustments, leading to reduced working life and increased maintenance needs.
Innovation Solution
The use of flexible cylindrical lines made of synthetic polymer fibers, such as nylon or polyester, twisted into strands and used as cylindroids, which are wound onto capstans driven by a reversible electric motor, providing high tension strength, low stretch, and improved wear resistance, while eliminating the need for large winches and reducing maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire cables are used for lifting mechanisms, then the door can be moved between positions, but the cables are subject to wear, corrosion, and require periodic adjustments
Solution Approach 1:
The patent replaces durable but maintenance-intensive wire cables with synthetic fiber straps that have different wear characteristics. The straps are designed to be replaced rather than repaired, eliminating the need for periodic adjustments and extensions of the lifting mechanism components.
Solution Approach 2:
The patent changes the material parameter from metal wire cables to synthetic polymer fibers. This material substitution fundamentally alters the wear and corrosion properties, providing straps that resist degradation better than traditional cables while maintaining the necessary tensile strength for door operation.
2Reliability
If wire cables are used for lifting mechanisms, then the door can be moved between positions, but the cables begin to fray when wrapped on lift drums
Solution Approach 1:
The synthetic fiber straps are designed with superior friction and wear resistance compared to wire cables. When wrapped around the lift drum, the straps maintain their integrity without fraying, extending the operational life of the lifting mechanism before replacement is needed.
Solution Approach 2:
The patent uses composite synthetic fiber constructions that combine multiple fiber types or treatments to create straps with enhanced wear resistance. These composite structures prevent the fraying that occurs with wire cables while maintaining the necessary mechanical properties for door lifting.
3Reliability
If synthetic polymer fiber cylindroids are used instead of wire cables, then wear and corrosion are reduced, but the cylindroids require large capstans that take up space
Solution Approach 1:
The patent changes the geometric parameter of the lifting element from thin wire cables to wider synthetic fiber straps. This parameter change allows the use of more compact capstans compared to traditional cable systems, as the straps distribute load over a larger surface area, reducing the required capstan diameter.
4Productivity
If the bi-fold door moves at constant speed, then the motor operates efficiently, but the door cannot accelerate or decelerate for smooth operation
Solution Approach 1:
The patent incorporates feedback control in the motor operation to regulate door movement speed dynamically. The system monitors door position and adjusts motor output to provide smooth acceleration and deceleration, improving operational smoothness while maintaining efficient motor operation through controlled speed variations.
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 enhances the speed and durability of bi-fold door operation, reduces maintenance requirements, and maintains consistent tension forces, extending the lifespan of the lifting mechanism while minimizing space occupancy.
Implementation Method 1
A power transmission operatively connected to the shaft is driven with a reversible electric motor to selectively rotate the shaft in opposite directions
Implementation Method 2
The capstans have disks with flat surfaces that engage the cylindroids to maintain the cylindroids in helical coil patterns between the disks
Implementation Method 3
The fibers are twisted into strands which are twisted or braided into a line. The polymer cylindroids have high tension strength, low stretch or elongated expansion, and good wear and weathering properties
Data Source
AI summary
An overhead bi-fold door mounted on a freestanding header has a door lift device with polymer cylindroids and capstans operated with an electric motor driven power transmission to selectively move the bi-fold door from an upright closed position to a folded open position and allow the bi-fold door to move from the folded open position to the upright closed position. Anchors mounted on the bi-fold door adjust the working length of the cylindroids between the capstans and anchors. The capstans have laterally spaced disks engageable with the cylindroids during the helical winding and unwinding of the cylindroid on the capstans as the bi-fold door moves at an increasing rate of speed from the upright closed to folded open positions and a decreasing rate of speed from the folded open to upright closed positions.