Folding Chair Leg Locking System for Stability Without User Weight
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Solution Overview
Problem
Folding chairs often suffer from discomfort due to pressure points on the seating surface, require user weight to stay open, and may have fabric that fades over time, compromising durability and aesthetics.
Innovation Solution
The design incorporates a folding chair leg locking system with a housing, trigger, latch, and bushing, along with a suspension fabric for the seat and backrest that includes a thermoplastic polyurethane film for durability and UV resistance. The leg locking system ensures the chair remains open during use and can be easily folded when needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a folding chair uses basic construction materials to maintain affordability, then cost is reduced, but durability and comfort deteriorate due to pressure points and fabric fading
Solution Approach 1:
The patent applies composite materials by combining different fabric types with contrasting properties - a first fabric with good colorfastness for outer surfaces that need UV resistance, and a second fabric with softness for interior surfaces contacting the user. This composite fabric construction allows the chair to simultaneously achieve durability against fading and comfort against pressure points, while remaining affordable through selective material application rather than using premium materials throughout.
2Device complexity
If a folding chair uses a simple locking mechanism, then device complexity is reduced, but reliability deteriorates because the chair requires user weight to stay open and may awkwardly fold when moved
Solution Approach 1:
The patent implements a self-latching locking mechanism that automatically engages and locks the chair in its open position without requiring continuous user input or weight dependency. The mechanism uses spring-loaded latches that automatically snap into place when the chair is opened, providing reliable stability. When closing, the latches automatically disengage, allowing easy folding. This self-service mechanism eliminates the need for user weight to maintain the open position while keeping the device complexity low.
3Ease of manufacture
If a folding chair uses basic fabric without UV protection, then manufacturing cost is reduced, but the fabric fades in color and appearance over time
Solution Approach 1:
The patent applies local quality by treating different portions of the fabric differently based on their functional requirements. The outer surfaces exposed to UV radiation are made from fabric with excellent colorfastness and UV resistance properties, while interior surfaces not exposed to elements use fabric optimized for comfort and softness. This localized application of specialized materials extends the lifespan and maintains the appearance of UV-exposed areas without requiring all fabric to be expensive UV-resistant material.
Data Source
AI summary
An adjustable chair may include a frame, a seat pan, a backrest, a pair of arm rests, at least two legs each comprising an inner leg configured to telescope out of an outer leg, and a leg locking system for locking the outer leg to the inner leg.