Lifting mechanism for armrest
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Solution Overview
Problem
Existing chair armrests are often fixed, causing discomfort due to user height and shape variations, and existing adjustable mechanisms are complex, costly, and prone to rubbing against walls during adjustment.
Innovation Solution
A lifting mechanism comprising an armrest bracket, guide unit, support unit, and control unit with positioning balls and elastic members for smooth, stable height adjustment, featuring a simple structure and reduced parts for easy assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a height adjustable armrest mechanism is added, then user comfort is improved, but device complexity and production cost increase
Solution Approach 1:
The adjustment mechanism is segmented into discrete height levels using multiple positioning recesses (first, second, third positioning recesses) on the guide post, allowing the armrest to be positioned at specific predetermined heights rather than requiring continuous adjustment, thereby simplifying the mechanism
Solution Approach 2:
A spring-loaded positioning ball acts as an intermediary between the control rod and the positioning recesses, automatically engaging with the recesses to lock the armrest at desired heights without requiring complex locking mechanisms or multiple separate components
2Adaptability or versatility
If a height adjustable armrest mechanism is added, then user comfort is improved, but assembly time and production throughput decrease
Solution Approach 1:
Multiple functional components are merged into integrated assemblies: the guide post combines positioning recesses and a guide structure, while the control rod integrates the positioning ball, spring, and limiting block into a single unit that performs both positioning and locking functions, reducing the number of separate parts to assemble
Solution Approach 2:
The spring-loaded positioning ball automatically engages with the positioning recesses when the armrest is moved to different heights, providing self-locking functionality without requiring additional fasteners, screws, or complex assembly steps, thereby simplifying the assembly process
3Device complexity
If the armrest adjustment mechanism is positioned on one side of the armrest, then structure is simplified, but the armrest turns during vertical movement and rubs against the cavity wall
Solution Approach 1:
The positioning ball is extracted from the control rod and placed on the armrest pad instead, separating the positioning function from the control mechanism and allowing the control rod to focus solely on vertical movement control, which reduces friction and improves adjustment smoothness
Solution Approach 2:
The positioning ball mounted on the armrest pad acts as an intermediary that contacts the positioning recesses directly, ensuring stable positioning while allowing the control rod to move freely without side forces, thereby preventing the armrest from turning during adjustment
4Reliability
If positioning balls are mounted on the control rod, then positioning function is achieved, but the armrest turns during vertical movement
Solution Approach 1:
Instead of mounting the positioning ball on the control rod as in conventional designs, this invention inverts the arrangement by mounting the positioning ball on the armrest pad and the positioning recesses on the guide post, which reverses the force transmission path and prevents the armrest from turning during vertical movement while maintaining accurate positioning
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 smooth and stable armrest adjustment with reduced production costs, faster assembly, increased service life, and lower maintenance, while avoiding rubbing against cavity walls.
Implementation Method 1
at least one elastic member arranged between a top end of the control rod and a bottom end of the armrest pad
Data Source
AI summary
A lifting mechanism for armrests is provided. A control rod of a control unit is mounted in a support unit disposed in a cavity of a guide unit. Positioning balls are mounted in through holes on two sides of the support unit for being locked in or separated from positioning recesses on two side walls of the cavity. When the control rod is pulled upward for height adjustment of the armrest, the positioning balls are fallen into concave portions of the control rod and separated from the positioning recesses of the cavity. Then the support unit can be pulled for adjustment of the armrest. When the support unit is moved vertically in the cavity of the guide unit, the two positioning balls are against and contact with the two side walls of the cavity to prevent the support unit from changing directions and ensure smooth movement of the armrest.