Variable-Torque Blind Control for Low-Effort Position Holding
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Solution Overview
Problem
Conventional control mechanisms for flexible coverings like blinds, such as those using torsion springs, require substantial user effort to wind or unwind, especially for larger blinds, and alternative solutions like electric motors are often expensive and complex.
Innovation Solution
A control apparatus with a variable torque device that includes a constant force spring and a flexible elongate member, allowing for adjustable counterbalance to match the weight of the blind material at any position, reducing the effort required to adjust the blind's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a torsion spring mechanism is used to counterbalance the blind weight, then the blind position can be maintained, but substantial user effort is required to wind/unwind the blind especially for larger blinds
Solution Approach 1:
The patent uses a constant force spring to provide a counterbalancing force that opposes the weight of the blind material. The spring is arranged to unwind as the blind is lowered, providing upward force to counterbalance the descending blind weight, thereby reducing the effort needed to operate the blind while maintaining position control throughout the full travel range.
2Reliability
If a torsion spring with gearing is used to maintain desired blind position, then position control is achieved, but the mechanism becomes complex and problematic
Solution Approach 1:
The patent extracts and eliminates the complex gearing mechanism from the traditional torsion spring system. By using a constant force spring directly connected to the blind material through a simple take-up spool, the invention removes the intermediate gearing components that caused complexity and reliability problems, while maintaining effective position control throughout the blind's travel range.
3Ease of operation
If electric motors are used to control blind position, then ease of operation is improved, but cost and complexity increase
Solution Approach 1:
The patent implements a self-service mechanical system where the constant force spring automatically provides the counterbalancing force needed to operate the blind. The spring unwinds as the blind is lowered, providing continuous upward force without requiring external power sources, control circuits, or motor components, thereby achieving ease of operation through pure mechanical means.
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 apparatus provides a counterbalance that matches the weight of the blind material throughout its travel, reducing user effort and maintaining the blind's position effectively from fully wound to fully unwound states, making it easier to operate and install.
Implementation Method 1
The variable torque device can include a first fixed housing, a movable carriage and at least one constant force device. The constant force device can be a constant force spring.
Implementation Method 2
The flexible elongate member can be a cable having a diameter in accordance with the thickness of the flexible covering.
Data Source
AI summary
A control apparatus for positioning and counterbalancing an amount of flexible blind material wound onto or unwound from a rotatable shaft of a windable covering such as a blind. The apparatus includes a main body and a variable torque device, at least partially fitted within the main body, having means of achieving a variable torque to prevent rotation of the shaft due to a variable weight of blind material hanging from the shaft in any position between a wound position and an unwound position of the blind material defining full travel of the windable covering.