Armrest mechanism for a chair
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Solution Overview
Problem
Conventional armrests in chairs often lack efficient mechanisms for vertical height adjustment, limiting user comfort and flexibility.
Innovation Solution
The armrest mechanism includes a support post with slideable members and an actuator that can be moved from a locked to an unlocked position, allowing the arm pad to be adjusted vertically by extending and retracting within channels, enabling precise height adjustment and user customization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If armrests are affixed immovably to the chair, then structural simplicity is maintained, but user comfort and adaptability are limited
Solution Approach 1:
The armrest mechanism is divided into separate functional components: an actuator for locking/unlocking, first and second slideable members for vertical movement, and channels for guiding motion. This segmentation allows each component to perform its specific function efficiently while maintaining overall system manageability despite the added adjustability feature.
Solution Approach 2:
The armrest transitions from a static, immovable state to a dynamic, adjustable state through the actuator mechanism. The slideable members can move vertically within channels when unlocked, and lock into position when locked, providing adaptability while maintaining structural integrity through controlled motion rather than complete rigidity.
2Manufacturing precision
If a simple locking mechanism is used, then ease of manufacture is improved, but precise height adjustment and secure locking are compromised
Solution Approach 1:
The actuator serves as an intermediary component that mediates between the user's manual input and the locking mechanism. It translates simple user action into precise engagement of the slideable members with the channels, achieving accurate height adjustment and secure locking without requiring complex manufacturing processes for the individual components.
Solution Approach 2:
The first slideable member is positioned within the second slideable member, creating a nested arrangement. This nesting allows both members to move vertically within the channels while maintaining compact packaging and simplifying the overall structure, as the nested configuration naturally guides motion and reduces the need for additional guiding components.
3Ease of operation
If the armrest allows free movement, then ease of adjustment is improved, but stability and secure positioning are lost
Solution Approach 1:
The armrest mechanism operates in periodic cycles: the actuator is activated to unlock, allowing free movement for adjustment; then the actuator is activated again to lock, securing the position. This periodic switching between locked and unlocked states provides ease of adjustment when needed while ensuring stability during use, as the armrest spends most time in the locked, stable position.
Solution Approach 2:
The spring member provides self-service by automatically biasing the actuator toward the locked position. After the user releases the actuator following an adjustment, the spring automatically returns the mechanism to the locked state without requiring additional user action, ensuring the armrest stabilizes securely while maintaining ease of operation through minimal user input.
Data Source
AI summary
An armrest for a chair includes a first slideable member moveably positioned within a support post and a second slideable member moveably positioned within the support post. The first slideable member is moveably positioned within a channel of the second slideable member such that the first slideable member is moveable relative to the second slideable member. An actuator is connected to the first and second slideable members. The actuator can optionally be included that is actuatable from a locked position to an unlocked position. The first and second slideable members are immovable within the post when the actuator is in the locked position and the first and second slideable members are moveable within the post when the actuator is in the unlocked position.