Foldable Chair Backrest Joint With Position-Limit Locking
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Solution Overview
Problem
Conventional person carrier chairs are either integral and non-collapsible, limiting storage space and requiring cumbersome assembly/disassembly, which is inconvenient for handicapped individuals who need assistance with mobility, especially those with paralysis, muscular dystrophy, or aged individuals with degenerated physiological functions.
Innovation Solution
A chair device with a position limit function achieved by mutual engagement between fan-shaped limit projecting members and recesses at pivot-joints, allowing for controlled unfolding and collapsing, along with reinforcing edge ribs for strength and convenient armrest integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the chair is designed as an integral non-collapsible structure, then the structural strength is improved, but the storage space efficiency deteriorates
Solution Approach 1:
The chair is divided into multiple detachable modules including seat unit, backrest unit, armrest units, and leg rest units that can be separated and stored independently, reducing storage space while maintaining structural integrity when assembled
Solution Approach 2:
The chair incorporates collapsible mechanisms with pivot joints and locking systems that allow the structure to transition between expanded (use) and collapsed (storage) states, dynamically adapting volume while preserving strength during operation
2Volume of moving object
If the chair is designed as a detachable structure to reduce storage space, then the storage space efficiency is improved, but the assembly and disassembly time increases
Solution Approach 1:
Multiple functional components are combined into integrated assemblies (e.g., armrest units integrated with backrest, leg rest units with seat) that reduce the number of separate parts to assemble while maintaining the collapsible functionality for space efficiency
3Volume of moving object
If the backrest unit is pivotally jointed to allow collapsing, then the storage efficiency is improved, but the position stability deteriorates
Solution Approach 1:
The locking mechanism provides positional feedback through engagement of locking protrusions with locking grooves at specific angles, ensuring the backrest unit maintains stable positions during use and preventing unintended movement while allowing controlled collapsing for storage
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 chair device provides enhanced mobility assistance with efficient angular displacement, improved strength support, and convenient assembly/disassembly, addressing the limitations of existing chairs by enabling controlled position changes and reinforced structural integrity.
Implementation Method 1
the position limit function is achieved by mutual engagement between a projecting member and a recess such that the chair has appropriate position limit effect in unfolding and collapsing
Data Source
AI summary
A chair device for a person carrier includes a backrest unit formed by a front backrest and a rear backrest. The backrest unit is pivotally joined to a seat unit in which two opposite fan-shaped limit projecting members are provided at each pivot-joint end of the seat unit. The fan-shaped limit projecting members can be angularly displaced to a position to be engaged with fan-shaped recesses in the pivot-joint ends of the rear backrest. The fan-shaped limit projecting members have a position limited space for angular displacement within the fan-shaped recesses so that the backrest unit of the chair can move in the range between a collapsing state and an unfolding state. Furthermore, strength reinforcing edge ribs are provided at both sides where the front backrest is assembled to the rear backrest.