Folding Chair Leg Locking System for Stable Unfolded Position
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Solution Overview
Problem
Folding chairs often lack comfortable seating due to pressure points and require user weight to maintain the open position, and their materials may fade over time, compromising durability and aesthetics.
Innovation Solution
A folding chair design featuring a leg locking system with a trigger and latch mechanism that allows for easy folding and unfolding, combined with a suspension fabric made from elastomeric yarns and thermoplastic polyurethane film for improved comfort and durability, which also includes a tensioning mechanism to maintain the chair's form without user weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a folding chair uses basic materials to reduce cost, then affordability is improved, but durability and color retention deteriorate
Solution Approach 1:
The patent applies composite materials by combining aluminum alloy frame with high-density polyethylene components. This composite construction provides both durability and UV resistance while maintaining affordability through efficient manufacturing processes.
Solution Approach 2:
The patent utilizes parameter changes by selecting specific material properties - aluminum alloy for the frame provides strength-to-weight ratio, while high-density polyethylene offers UV resistance and color retention. These parameter selections resolve the contradiction between cost and durability.
2Device complexity
If a folding chair uses simple structure to reduce complexity, then ease of manufacture is improved, but stability deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the chair into modular components - the frame, seat, backrest, and leg locking system are separate assemblies that can be manufactured independently and assembled together. This segmentation maintains simplicity while ensuring stability through precise connection points.
Solution Approach 2:
The leg locking system employs self-service mechanism where the latch automatically engages with the leg position through spring-loaded action. The system self-regulates to maintain stable leg positioning without requiring complex control mechanisms.
3Device complexity
If a folding chair lacks leg locking system to reduce complexity, then device complexity is improved, but stability deteriorates
Solution Approach 1:
The leg locking system uses spring-loaded latches that automatically engage with the leg position indicators. The springs provide continuous force to maintain locked position, and the system self-latches without requiring additional actuators or complex control mechanisms.
Solution Approach 2:
The patent introduces position indicators as intermediary elements between the leg locking system and the user. These indicators provide visual feedback about leg position status, mediating the interaction between the mechanical locking system and user perception without adding mechanical complexity.
4Device complexity
If a folding chair uses traditional seating surface to reduce complexity, then device complexity is improved, but comfort deteriorates
Solution Approach 1:
The patent applies flexible shells by using a molded polyethylene seat shell that contours to the user's body. This single-piece molded shell provides ergonomic shaping and pressure distribution without requiring complex cushioning systems or multiple components.
Data Source
AI summary
A chair may include a frame, a seat pan, a backrest, a pair of arm rests, and a plurality of legs wherein at least two legs may each provided with an inner leg and an outer leg and the inner leg is configured to telescope out of the outer leg, wherein the at least two legs may include a leg locking system for locking the outer leg to the inner leg when the chair is in an unfolded position, wherein the leg locking system may include a trigger housing, a trigger, and a latch, and wherein the latch may be configured to engage a bushing on the inner leg.