Chair with dynamic motion features
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Solution Overview
Problem
Existing chair designs struggle to provide optimal comfort and support while allowing for dynamic movement without compromising stability and manufacturability.
Innovation Solution
A compliant chair backrest assembly featuring a back frame with flexural members and reinforcement supports that adjust stiffness based on engagement, incorporating a back frame with flexural members and reinforcement braces that increase stiffness progressively with deflection, ensuring linear and asymptotic load responses for enhanced support and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If flexural members are used to allow dynamic movement and comfort, then comfort and adaptability are improved, but stability and structural rigidity deteriorate
Solution Approach 1:
The backrest assembly uses flexural members with progressive engagement braces that allow dynamic movement during normal use but provide increasing resistance as deflection increases, transitioning from a flexible state to a more rigid state under load
Solution Approach 2:
The system changes its effective stiffness parameter dynamically through progressive engagement of braces with flexural members, allowing the structure to adapt its rigidity based on the magnitude of applied forces
2Stability of the object's composition
If reinforcement braces are added to increase stability, then structural rigidity is improved, but device complexity and manufacturing difficulty worsen
Solution Approach 1:
The reinforcement system is divided into multiple discrete braces that can selectively engage with flexural members at different deflection stages, rather than using a single complex continuous structure
Solution Approach 2:
The braces are selectively engaged only when needed (during deflection beyond a certain point), rather than being continuously active, reducing the overall complexity while maintaining stability when required
3Reliability
If progressive engagement mechanism is implemented, then load response control is improved, but manufacturing precision requirements worsen
Solution Approach 1:
The design incorporates pre-engineered engagement points and geometries that naturally guide the progressive engagement process, cushioning against variations in manufacturing precision through built-in geometric constraints
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 solution provides a chair backrest that dynamically adjusts to user movements, maintaining stability and comfort by ensuring linear and asymptotic load responses, thus enhancing user experience and manufacturability.
Implementation Method 1
the first flexural member progressively engages with the first brace when the first flexural member is deflected
Implementation Method 2
the first lower contact surface of the first flexural member progressively engages with the first upper contact surface of the first brace when the first flexural member is deflected
Implementation Method 3
An overall stiffness of the first flexural member increases in accordance with progressively increasing engagement of the first flexural member with the first brace
Data Source
AI summary
A compliant chair backrest assembly includes a back frame (58) having a first frame side (58a), a second frame side (58b), a lower portion (581) and an upper portion (58u) that extends from the lower portion (581). The upper portion (581) of the back frame is configured to engage with a back of a user and the lower portion (581) includes a first flexural member (70) and a nexus (74). The first flexural member (70) defines a first lower contact surface (90a) and has a flexural rigidity. The lower portion (581) also includes a reinforcement support (62) including a first brace (100) defining a first upper contact surface (110a) and having a flexural rigidity that is greater than the flexural rigidity of the first flexural member (70).