Retractable Armrest Structure for Compact Foldable Chairs
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Solution Overview
Problem
Conventional metallic foldable chairs with armrests cannot be independently extended or retracted, limiting their usability for users of larger body size and complicating storage due to complex folding structures.
Innovation Solution
A foldable chair design featuring pivotally connected leg frames, a support beam, and a rail with a locking portion allows armrests to be independently extended or retracted, using a torque spring for effortless operation and secure positioning, enabling parallel folding with the chair body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If armrests are added to metallic foldable chairs, then user comfort is improved, but the chair cannot be stored compactly parallel with other chairs
Solution Approach 1:
The armrest is designed with dynamic movement capability, allowing it to rotate between a horizontal extended position (for user comfort during use) and a vertical retracted position (for compact storage). The pivotal link mechanism enables the armrest to change its spatial orientation dynamically, resolving the contradiction between comfort and storage efficiency.
2Adaptability or versatility
If multiple pivotal links are used to enable armrest retraction, then armrest folding capability is improved, but the structure becomes more complex
Solution Approach 1:
The armrest system is segmented into distinct functional components: the armrest body, the support beam, and the pivotal link mechanism. This segmentation allows each component to perform its specific function independently while maintaining overall system simplicity. The pivotal link acts as a separate articulated connector that enables folding without requiring complex integrated mechanisms.
3Strength
If armrests are coupled with the rear leg frame, then armrest support is improved, but the armrests cannot be operated independently
Solution Approach 1:
The armrest assembly is segmented from the rear leg frame coupling. The support beam maintains the structural connection to the rear leg frame for strength, while the armrest itself is separated and connected through a pivotal link to the front leg frame. This segmentation enables independent operation of the armrest while preserving the supportive function of the rear leg frame connection.
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
Facilitates user-adjustable armrests for comfort and independent operation, simplifies the folding process, and allows multiple chairs to be stored compactly parallel to each other, optimizing storage space.
Implementation Method 1
Because a torque spring is coupled between the second pivotal link and the support beam, unfolding of the armrest by the support beam will load the spring. When the support beam disengages the locking portion, the resilient force loaded in the spring is released to move the support beam and pull the armrest downward
Data Source
AI summary
A foldable chair has an armrest retracting structure that includes two plate elements placed below each armrest, each plate element having a guide slot with a linear section and a reverse turn section. A first pivotal axle passes through the plate elements and connects with the front leg frame. A support beam has an end through which a second pivotal axle is mounted, the second pivotal axle being connected with the front leg frame. An opposite end of the support beam is secured in the slots through a bolt. By moving the support beam, the armrest can be deployed or retracted. When the bolt is lodged in the reverse turn section, the armrest can be locked in the deployed position.