Window Covering Locking Mechanism for Stable Bottom Rail Positioning
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Solution Overview
Problem
Traditional window covering systems face challenges in controlling the friction force effectively, leading to instability of the bottom rail's position due to elastic fatigue in the spring box and varying user preferences for operable height, making it inconvenient to lock and unlock at desired positions.
Innovation Solution
A window covering system with a locking device coiled to a first rotating unit, featuring a fixed and free end, and an actuating device that reduces the restriction force to allow the bottom rail to descend by gravity, enabling locking and unlocking at any position, and accommodating different user heights through a convenient operation method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking device is provided to fix the bottom rail at any position, then the bottom rail can remain stationary regardless of gravity, but the locking device must be unlocked to descend the bottom rail and expand the covering material
Solution Approach 1:
The locking device is designed to automatically lock when the bottom rail is at the desired position and automatically unlock when the user pulls the control cord, eliminating the need for manual intervention to engage or disengage the locking mechanism. The system uses the user's pulling action on the control cord to directly trigger the unlocking sequence.
Solution Approach 2:
The control cord acts as an intermediary between the user and the locking device. When the user pulls the control cord, it transmits force through the winding spool and gear mechanism to trigger the unlocking of the locking device, providing a convenient and indirect method to operate the complex locking mechanism.
2Adaptability or versatility
If the weight of the covering material and the bottom rail with the force provided by the spring box are balanced by the friction force of the whole window covering system, then the bottom rail can stop at any position to retain the level of light blockage of the covering material, but the friction force of the whole window covering system is difficult to be controlled effectively
Solution Approach 1:
The locking function is extracted from the friction-based position holding mechanism. Instead of relying on friction force to maintain position, the patent introduces a dedicated locking device that mechanically engages with the first rotating unit, separating the position adjustment function (via friction) from the position holding function (via mechanical locking).
Solution Approach 2:
The position control system is segmented into two independent subsystems: a friction-based positioning subsystem that allows the bottom rail to stop at any position, and a mechanical locking subsystem that secures the position once reached. This segmentation allows each subsystem to optimize its function without compromising the other.
3Force
If the force provided by the spring box is generated by the elasticity of a spiral spring within the spring box, then the spring box can provide lifting force, but the spiral spring has a problem of potential elastic fatigue
Solution Approach 1:
The patent changes the physical state of the spring from a compressed spiral spring to a twisted coiled spring (torsion spring). This parameter change in the spring's configuration and loading mode reduces elastic fatigue by distributing stress more evenly along the spring coils, thereby improving durability while maintaining the lifting force function.
4Length of moving object
If the bottom rail ascends to the headrail, then more covering material accumulates on the bottom rail, but the heavier the overall weight of the bottom rail and the covering material, thus it is likely that the bottom rail would more or less descend for a distance from a desired position
Solution Approach 1:
The locking device is engaged at the desired position before the weight of the covering material can cause the bottom rail to descend. By preemptively activating the mechanical lock, the system counteracts the gravitational force that would otherwise cause position drift, ensuring the bottom rail remains stationary at the intended position regardless of the accumulated covering material weight.
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 system provides stable locking and unlocking functionality at any position, addressing the friction control issues and accommodating varying user preferences, ensuring the bottom rail remains stationary and easy to operate.
Implementation Method 1
the locking device is configured to provide a restriction force to the first rotating unit in order to restrict the first rotating unit from rotating in the first direction, as well as to restrict the bottom rail from descending
Implementation Method 2
when the rotation restriction to the first rotating unit is removed, the bottom rail descends by gravity to drive the first rotating unit to rotate in the first direction
Data Source
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AI summary
A window covering system comprises a headrail, a bottom rail, a covering material, a control unit, and a first rotating unit, wherein the first rotating unit is configured to be driven to rotate in a first direction when the bottom rail descends to expand the covering material; and a locking device coiled to the first rotating unit, wherein the locking device provides a restriction force to the first rotating unit to restrict the first rotating unit from rotating in the first direction, as well as to restrict the bottom rail from descending; and an actuating device configured to operate with the control unit simultaneously; when the control unit drives the actuating device to push the locking device in order to reduce the restriction force provided by the locking device to the first rotating unit, the bottom rail descends to drive the first rotating unit to rotate in the first direction.