Window Blinds Mechanism with Planetary Gears
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Solution Overview
Problem
Conventional window blinds mechanisms with spring reels and string reels lack a direct transmission relationship, leading to instability and increased structural costs due to the need for larger transmission mechanisms and higher-priced spring leaves.
Innovation Solution
A window blinds mechanism featuring a rope reel with planetary gears, a driving wheel, and scroll springs, which reduces the spring rate and volume, thereby lowering costs and allowing flexibility in spring selection based on curtain material volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional spring reel and string reel are used without direct transmission relationship, then the transmission mechanism can be simpler, but the torque is insufficient and the spring volume and cost increase
Solution Approach 1:
A friction wheel is introduced as an intermediary component between the motor and the spring reel. The friction wheel transmits torque to the spring reel through friction contact, enabling direct transmission relationship while maintaining simple structure. This intermediary allows the motor to effectively drive the spring reel without requiring complex gear reductions, thus providing sufficient torque while keeping the overall mechanism simple and cost-effective.
2Volume of moving object
If high reduction ratio planetary gears are used, then the spring rate can be reduced and spring volume decreased, but the device complexity and assembly space increase
Solution Approach 1:
The patent replaces the traditional mechanical gear reduction system with a friction-based transmission system. Instead of using planetary gears to achieve torque multiplication, a friction wheel is used to transmit torque directly to the spring reel through friction contact. This substitution eliminates the need for complex gear mechanisms while achieving the same functional outcome, thereby reducing device complexity and assembly space requirements.
3Force
If the spring leaf thickness and width are increased to provide different elastic force, then the elastic force increases, but the spring volume and cost increase
Solution Approach 1:
The patent changes the transmission ratio parameter of the friction transmission system to achieve torque multiplication. By adjusting the radius ratio between the friction wheel and the spring reel, the system can provide sufficient torque to the spring without requiring the spring itself to have increased thickness or width. This parameter change allows the spring to maintain its original dimensions while still achieving the required elastic force through the mechanical advantage provided by the friction transmission.
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 achieves reduced spring length and volume, lowering costs and allowing for customizable spring selection, while maintaining effective operation and stability of the blinds.
Implementation Method 1
the driving gear of the first rolling wheel is engaged with the driving wheel through the planetary gears, with the high reduction ratio of the planetary gears
Implementation Method 2
the spring rate of the scroll spring can be reduced which reduces the length and volume of the scroll spring
Implementation Method 3
The at least two dampers are disposed on two sides of the rope reel, for slowing down the falling speed of the rope through friction
Data Source
AI summary
A window blinds mechanism has a blinds member, a rope reel and at least two dampers. The rope reel has a bottom casing, a first rolling wheel, a second rolling wheel, a plurality of planetary gears, a top casing, a driving wheel and an upper cover. The driving gear of the first rolling wheel is engaged with the driving wheel through the planetary gears, with the high reduction ratio of the planetary gears, the spring rate of the scroll spring can be reduced which reduces the length and volume of the scroll spring. It not only helps to reduce the cost of the scroll spring, but also allows the flexibility to choose the number of the scroll spring according to the curtain material volume.