Chair or armchair with adjustable backrest
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Solution Overview
Problem
Existing adjustable backrest chairs do not consistently provide optimal back support across different angular positions, failing to maintain suitable contact and support for users in various working postures.
Innovation Solution
A chair with a backrest support mechanism featuring an articulated parallelogram structure and elastic return means, allowing the backrest to maintain parallel alignment while adjusting to optimal positions, combined with a locking and adjusting device for easy user operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the backrest is made adjustable in angular position, then the adaptability to different working postures is improved, but the ability to maintain optimal back support contact is worsened
Solution Approach 1:
The backrest support mechanism employs a dynamic articulated parallelogram structure with two arms hinged at multiple axes, allowing the backrest to adjust angularly while maintaining parallel alignment. This dynamic structure enables the backrest to adapt to different working postures (improving adaptability) while the parallelism constraint ensures consistent back support contact quality (maintaining reliability) across all angular positions.
2Reliability
If the backrest support structure is made more complex to maintain parallel alignment, then the back support quality is improved, but the device complexity increases
Solution Approach 1:
The backrest support mechanism is segmented into two distinct arms (first arm 16 and second arm 20), each hinged at separate axes. This segmentation allows independent movement control while maintaining the overall parallel alignment. The articulated parallelogram structure divides the complex motion requirement into simpler, manageable rotational joints, achieving reliable back support contact without excessive overall structural complexity.
3Ease of operation
If the backrest is made easily adjustable by the user, then the ease of operation is improved, but the structural complexity of the locking mechanism increases
Solution Approach 1:
The locking and adjusting device (4) is designed to be operated directly by the user through intuitive manual manipulation. The device allows users to adjust the backrest to desired positions and lock them in place through simple hand-operated mechanisms. This self-service approach improves ease of operation while the modular locking design keeps the structural complexity manageable by using straightforward mechanical engagement rather than complex multi-component systems.
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
Ensures optimal back support and contact in any angular position, allowing users to adjust the backrest easily and maintain comfort during prolonged sitting tasks without compromising posture.
Implementation Method 1
Said return means are elastic and comprise at least one spring 30, or equivalent component, operating on one of said arms 16, 20
Data Source
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AI summary
A chair assembly (1) of a chair or an armchair comprises a seat body (2), a backrest body (6), a locking and adjustment device (4), and a backrest support (10). The backrest support (10) is engaged with an articulated parallelogram that allows the position of the backrest body (6) to be changed while keeping it parallel to itself. The backrest support (10) further comprises spring return means.