Blind Body Positioning Mechanism for Non Pull Cord Window Blinds
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Solution Overview
Problem
Non pull cord window blinds suffer from rebounding after extension and sagging after retraction due to lack of effective positioning design, complicating user operation.
Innovation Solution
A blind body positioning mechanism comprising a casing, resistance units with one-way pawls and resistance wheels, transmission wheels, transmission cords, and a coil spring, which utilizes friction resistance and one-way engagement to maintain blind body positioning, preventing rebounding and sagging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If non pull cord window blind is used for easy operation, then ease of operation is improved, but positioning stability deteriorates causing rebounding and sagging
Solution Approach 1:
The blind body positioning mechanism is divided into independent resistance units, each comprising a resistance wheel, one-way pawl, and transmission cord. This segmentation allows each unit to independently provide positioning function, ensuring stable positioning while maintaining easy operation of the entire blind system.
Solution Approach 2:
The one-way pawl acts as an intermediary element between the resistance wheel and the transmission cord. It transmits force in one direction while preventing reverse motion, thereby achieving stable positioning without complicating the user operation. The pawl engages with the resistance wheel teeth to prevent backward movement while allowing forward movement during extension.
2Stability of the object's composition
If resistance units with one-way pawls are added to improve positioning stability, then positioning stability is improved, but device complexity increases
Solution Approach 1:
The resistance wheel serves multiple functions: it provides friction resistance to prevent rebounding, engages with the one-way pawl for positioning, and transmits force from the transmission cord. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while achieving improved positioning stability.
Solution Approach 2:
The one-way pawl automatically engages with the resistance wheel teeth when the blind body reaches the desired position, providing self-positioning without requiring additional control mechanisms. The friction resistance is automatically generated by the resistance wheel, eliminating the need for external positioning devices and keeping the overall structure relatively simple.
3Stability of the object's composition
If friction resistance is increased to prevent rebounding, then positioning stability is improved, but force required for operation increases
Solution Approach 1:
The resistance mechanism is designed to provide dynamic friction resistance that adapts during operation. During extension, the user overcomes the friction resistance to move the blind body. Once positioned, the same friction resistance prevents rebounding. The one-way pawl dynamically engages only when reverse motion is attempted, allowing easy forward movement while providing stable positioning.
Solution Approach 2:
The friction resistance, which could be considered a harmful force opposing user operation, is converted into a beneficial positioning force. The resistance wheel's friction with the transmission cord prevents the blind body from rebounding after extension. The one-way pawl converts the potential harmful reverse motion into a stable positioned state, making the friction force work in favor of positioning stability.
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 effectively holds the blind body in extended or retracted positions by balancing friction resistance with elastic restoring force, enhancing operational convenience and usability.
Implementation Method 1
Each resistance unit comprises a one-way pawl and a resistance wheel. The one-way pawl is pivotally mounted in the casing. The resistance wheel comprises a resistance wheel axle and a one-way sprocket. The one-way sprocket is fixedly connected to one end of the resistance wheel axle and meshed with the one-way pawl.
Implementation Method 2
each resistance unit further comprises a resistance shrapnel. The resistance shrapnel is mounted in the casing, comprising an elastic arm and a friction portion located at the elastic arm. The resistance wheel of each resistance unit comprises a friction wheel fastened to an opposite end of the respective resistance wheel axle and stopped against the friction portion of the associating resistance shrapnel to enhance the resistance effect of the resistance unit.
Implementation Method 3
The coil spring connects the two second transmission wheels, and alternatively wound round one of the two second transmission wheels during rotation of the two second transmission wheels.
Data Source
AI summary
A window body positioning mechanism of a non pull cord window blind includes two first transmission wheels, two transmission cords respectively connected with one ends thereof to the first transmission wheels, two second transmission wheels meshed together and respectively meshed with the first transmission wheels, a coil spring connecting the two second transmission wheels and selectively wound round one second transmission wheel, and two resistance units each including a one-way pawl and a resistance wheel wound by one respective transmission cord and meshed with the one-way pawl. Thus, when extending out or receiving the blind body, the friction resistance between the resistance wheels and the transmission cords and the engagement relationship between the resistance wheels and the respective one-way pawls help achieve excellent blind body positioning effects.