Rotatable Chair Armrest With Torque Resistance for Stability
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Solution Overview
Problem
Existing rotatable armrests for chairs often exhibit instability when users apply force while rising, leading to unwanted lateral rotation, which can cause instability and discomfort.
Innovation Solution
The armrest design incorporates low density plastic material and a torque resistor structure between the first and second members to resist rotational movement, allowing controlled rotation when seated and stability when rising, using a combination of deformable and non-deformable materials and torque restrictors to manage rotational forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the armrest is made selectively rotatable about a vertical axis to allow multi-position adjustment, then the ease of operation is improved, but the stability deteriorates when users apply force while rising
Solution Approach 1:
The armrest system transitions from a static fixed position to a dynamic selectively rotatable position. The mechanism allows the armrest to rotate about a vertical axis when users apply lateral force, enabling multi-position adjustment. The detent mechanism provides discrete stable positions during rotation, combining ease of operation with controlled stability.
Solution Approach 2:
The detent mechanism provides preliminary resistance to rotational movement by requiring users to apply sufficient lateral force to overcome the detent engagement before rotation can occur. This preliminary anti-action prevents unintended rotation while allowing deliberate repositioning when users actively push the armrest laterally.
2Ease of operation
If the armrest allows free rotation for comfort adjustment, then the ease of operation is improved, but unwanted lateral rotation occurs causing user instability
Solution Approach 1:
The detent mechanism acts as an intermediary between the armrest and the user's lateral force. It selectively engages and disengages to control rotational movement, allowing rotation only when sufficient force is applied to overcome the detent engagement. This intermediary mechanism prevents unwanted rotation during normal use while enabling deliberate repositioning.
Solution Approach 2:
The system changes the resistance parameter dynamically based on the applied force. When users apply lateral force greater than the detent engagement force, the armrest rotates freely to a new position. When no significant lateral force is applied, the detent mechanism maintains high resistance to prevent unwanted rotation, thus eliminating instability.
3Adaptability or versatility
If prior art structures are used to provide rotatable armrests, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The patent combines the rotational adjustment mechanism and the stability control mechanism into a single integrated structure. The detent mechanism is incorporated directly into the armrest assembly, merging the functions of rotation control and position locking without requiring separate complex mechanisms. This integration achieves multi-position adaptability while minimizing structural complexity.
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 effectively inhibits unwanted rotation during user movement, providing stability and comfort by resisting rotational movement with a controlled detent mechanism and torque resistance, allowing smooth rotation when desired.
Implementation Method 1
a torque resistor disposed about the axis of rotation... for resisting rotational movement of the first member relative to the second member
Implementation Method 2
low density plastic material which resists movement therebetween... high density plastic material is provided between the first and second members to permit selective rotational movement
Data Source
AI summary
An armrest for a chair having a first member connected to the chair; a second member selectively rotatable relative the first member; means disposed between the first and second members for resisting the rotational movement between the first and second members.