Self-Raising Window Covering With Constant-Force Clutch Control
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Solution Overview
Problem
Conventional window coverings, such as Venetian blinds, cellular shades, and Roman shades, face issues with cords posing hazards, affecting aesthetics, and experiencing wear due to friction, while roller shades are incompatible with these designs and often result in uncontrolled rapid retraction due to strong torsional springs, making it difficult to lower the shades without damaging them.
Innovation Solution
A self-raising window covering mechanism featuring a head rail, shade element, bottom rail, and a control mechanism with a drive axle and cord winding assembly that provides a constant rotational force, allowing the window covering to raise without user intervention, using a clutch member to lock and unlock the drive axle for controlled retraction and a deceleration member to slow the rise as it approaches the fully open position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If cords are used for raising and lowering window coverings, then the window covering can be operated to raise and lower, but cords pose safety hazards to children and affect aesthetics
Solution Approach 1:
The patent removes cords entirely from the window covering system. Instead of using cords for raising and lowering, the invention employs a spring-loaded mechanism with a clutch that operates through a simple pull-on-the-bottom-rail action, eliminating the harmful cords while maintaining operational functionality
Solution Approach 2:
The spring mechanism provides self-raising functionality, automatically lifting the window covering when the clutch is engaged. The system serves itself by using the spring's stored energy to counterbalance the weight of the shade, requiring minimal user intervention (only enough to engage/disengage the clutch)
2Ease of operation
If cords are used for raising and lowering window coverings, then the window covering can be operated, but cords experience substantial wear due to friction
Solution Approach 1:
The patent eliminates cords from the system entirely, replacing them with a spring mechanism and clutch assembly. This removes the component subject to frictional wear during operation, thereby improving reliability and durability
Solution Approach 2:
The invention replaces the cord-based mechanical lifting system with a spring-based mechanical system. The spring provides the lifting force, and the clutch provides the engagement/disengagement mechanism, eliminating the need for cords that would otherwise wear from repeated friction
3Force
If very strong torsional springs are used to accommodate maximum weight, then the window covering can be raised, but the retraction rate becomes too fast and uncontrolled
Solution Approach 1:
The patent employs a clutch mechanism that dynamically controls the engagement and disengagement of the spring force. The clutch allows the user to engage the spring for lifting and then disengage it to control the lowering speed, providing dynamic adjustment of the force application rather than a fixed strong-spring configuration
Solution Approach 2:
The clutch mechanism provides feedback control by allowing the user to sense the lifting force and manually control the engagement/disengagement timing. This feedback loop enables the user to regulate the retraction speed by controlling when the clutch disengages, preventing uncontrolled fast movement
4Shape
If roller shade mechanism is used, then flat shade material can be rolled up neatly, but the mechanism is not compatible with cellular shades, Venetian blinds, and Roman shades
Solution Approach 1:
The patent designs a universal lifting mechanism based on a spring and clutch system that can accommodate various window covering types including cellular shades, Venetian blinds, and Roman shades. The mechanism does not depend on the shade being rolled up, making it compatible with gathered and stacked configurations of different covering types
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 mechanism allows for safe, aesthetically pleasing, and controlled operation of window coverings by eliminating the need for cords, reducing wear, and enabling smooth, controlled retraction and raising without excessive force, addressing the issues of hazard, aesthetics, and mechanical stress.
Implementation Method 1
a spring unit including a constant force coil spring operatively connected between the drive axle and the head rail
Implementation Method 2
a clutch member operable to lock and unlock rotation of the drive axle
Data Source
AI summary
The present invention relates to a self-raising window covering and a control mechanism for the window covering. In particular, the window covering includes a drive unit, such as constant force spring, that is adapted to apply a substantially constant rotational force on the drive axle. A cord winding assembly is coaxially mounted on the drive axle, and includes at least one winding drum operatively connected to a second end of the raising cord and having a tapered portion, as well as a rotatable positioning member for moving the cord winding assembly laterally along the drive axle upon rotation of the positioning member. The cord winding assembly is adapted to translate the rotational force on the drive axle to a raising force on the raising cord, wherein the raising force is greater than a downward force exerted by the shade element and bottom rail throughout the range of opening and closing. A clutch member or locking member is also operatively connected with the axle and adapted to releasably lock the drive axle in a desired position.