Articulated Folding Chair Backrest for Compact Closure
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Solution Overview
Problem
Folding chairs with fixed backrests to the front legs are uncomfortable due to the backrest forming an angle greater than 90° relative to the seat, and when the backrest is perpendicular, the chair occupies excessive space in the closed position.
Innovation Solution
A folding chair design where the backrest is articulated to tilt forward in the open position and aligns with the chair's structure in the closed position, using a pair of joints and rods with helical compression springs to manage the backrest's orientation, allowing for minimal storage space without compromising comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the backrest is fixed to the front legs structure, then the chair structure is simple, but the backrest forms an angle greater than 90° relative to the seat making the chair uncomfortable
Solution Approach 1:
The backrest is made dynamically adjustable through an articulation mechanism with joints and rods, allowing it to change orientation between a perpendicular position (providing comfort) and an aligned position (reducing storage space). This dynamic capability resolves the contradiction between structural simplicity and seating comfort.
2Ease of operation
If the backrest is perpendicular to the seat in the position of use, then seating comfort is improved, but the chair occupies large overall dimensions in the closed position
Solution Approach 1:
The backrest transitions from a static perpendicular position to a dynamic configuration where it can tilt backward and align with the chair structure during closure. This dynamic adjustment minimizes the volume occupied in storage while maintaining comfort during use.
Solution Approach 2:
The backrest is designed to nest within or align with the chair structure when closed, similar to nested dolls, thereby reducing the overall dimensions and storage space required while maintaining its functional form during use.
3Volume of moving object
If the backrest is aligned to the structure defining the front legs, then the chair occupies minimal storage space, but the backrest forms an angle greater than 90° relative to the seat reducing comfort
Solution Approach 1:
The articulation mechanism with joints and rods enables the backrest to dynamically assume different orientations - aligned with the structure for minimal storage and perpendicular to the seat for comfort. This dynamic adaptability resolves the contradiction between compact storage and seating comfort.
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 provides comfortable seating with the backrest perpendicular to the seat in use while maintaining compact dimensions in storage by tilting the backrest backward during closure.
Implementation Method 1
using a pair of joints and rods with helical compression springs to manage the backrest's orientation
Data Source
AI summary
A folding chair comprising a seat and a backrest carried by a folding structure, wherein the folding structure comprises a first structure defining a pair of front legs and a second structure defining a pair of rear legs, articulated to each other about a transverse axis by means of a pair of joints and movable relative to one another between an open position and a closed position, wherein the first structure comprises two first side elements and the second structure comprises two second side elements and wherein each of said joints comprises a first half-joint fixed to a respective first side element and a second half-joint fixed to a respective second side element, wherein the first and the second half-joints are rotatable relative to one another about said transverse axis, wherein the first structure comprises a pair of rods mounted within respective first side elements and movable between a raised position and a lowered position.