One-Way Clutch Brake for Non-Pull Cord Window Blind
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Solution Overview
Problem
Conventional non pull cord window blinds lack a positive positioning design, leading to rebounding issues when fully extended and dropping issues when fully received, complicating user operation.
Innovation Solution
A blind body brake mechanism comprising a casing, rolling-up unit, transmission units, and one-way clutch units, which includes meshed coil spring winding wheels, cord-transfer gearwheels, and one-way clutch units with planetary gears and stop blocks, allowing for secure positioning of the blind body in both extended and received states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional non pull cord window blind structure is used, then the blind body can be easily adjusted between extended and received positions, but the blind body lacks positive positioning and experiences rebounding when fully extended or dropping when fully received
Solution Approach 1:
The patent employs a dynamic braking mechanism that transitions between two states: during extension, the planetary gears are disengaged from the stop blocks allowing free rotation; during positioning, the planetary gears engage with the stop blocks to provide dynamic braking and prevent rebounding. This dynamic engagement/disengagement resolves the contradiction between ease of operation and positioning stability.
Solution Approach 2:
The planetary gears serve as an intermediary element between the lift cord and the blind body. They transmit the lifting force while also providing the braking function through engagement with the stop blocks. This intermediary mechanism enables both smooth operation and reliable positioning without requiring separate components for each function.
2Reliability
If a braking mechanism is added to prevent rebounding and dropping, then positioning stability is improved, but the device complexity increases
Solution Approach 1:
The patent merges the braking function with the existing transmission mechanism by integrating planetary gears into the cord-transfer gearwheel assembly. The planetary gears are combined with the stop blocks to form a unified braking system that works within the existing structure, avoiding the need for separate independent braking components and thus limiting the increase in device complexity.
Solution Approach 2:
The planetary gears perform multiple functions: they transmit the lifting force from the lift cord, provide braking action when engaged with stop blocks, and allow free rotation when disengaged. This multi-functionality reduces the need for additional dedicated components, thereby limiting the increase in device complexity while achieving reliable positioning.
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 provides simple and stable operation by firmly securing the blind body in position, preventing rebounding and dropping, and ensuring easy extension and retraction, suitable for large size non pull cord window blinds.
Implementation Method 1
The rolling-up unit comprises two meshed upper coil spring winding wheels, two meshed lower coil spring winding wheels, an upper coil spring and a lower coil spring
Implementation Method 2
Each planetary gear is rotatably mounted in one respective rolling groove and meshed with the internal gear of the one-way wheel so that each planetary gear is movable in one respective rolling groove by the internal gear of the one-way wheel in one of two reversed directions into engagement with or away from one stop block
Implementation Method 3
The one-way wheel is rotatably sleeved onto the wheel axle and wound round by one of the lift cords, so that the one-way wheel can be driven to rotate by the lift cord which is wound round by the one-way wheel
Data Source
AI summary
A blind body brake mechanism for non pull cord window blind utilizes two one-way clutch units to control the positioning of the blind body during the extending or receiving operation. Each one-way clutch unit includes a wheel axle, multiple stop blocks equiangularly connected to the wheel axle, an arched rolling groove defined between each two adjacent stop blocks, a planetary gear movably mounted in each arched rolling groove, and a one-way wheel mounted on the wheel axle and having an internal gear meshed with the planetary gears.