Folding Chair Backrest Linkage for Shorter Folded Height

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Solution Overview

Problem

Conventional folding chairs have a long rear support leg that increases the size of the chair frame when folded, making storage and transportation cumbersome.

Innovation Solution

A folding chair design where the backrest rod is linked with cross struts and connected to the rear leg, allowing the seat and armrest rods to fold forward, reducing the overall height and length of the chair frame, and enabling compact retraction of the rod members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the rear support leg is made long to serve as the backrest, then the backrest support function is improved, but the folded chair size increases making storage and transportation difficult

Engineering Contradiction:

Improvebackrest support functionVSAvoidfolded chair size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The backrest function is segmented from the rear support leg by introducing a separate backrest rod that can independently fold and connect to the seat rod. This allows the rear support leg to be shorter while maintaining backrest support through the separate backrest rod mechanism.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The backrest rod is designed to be dynamically connected to the seat rod through a pivot connection, allowing it to extend when needed for backrest support and retract when folded. This dynamic mechanism enables the backrest function without requiring a permanently long rear support leg.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If the chair frame is designed with traditional cross legs, then the structure is simple, but the folded height remains relatively large

Engineering Contradiction:

Improvestructure simplicityVSAvoidfolded chair height

Core Design Contradiction:

Device complexityVSLength of stationary object

Solution Approach 1:

The folding mechanism transitions from traditional horizontal cross-leg folding to a vertical folding dimension where the backrest rod folds downward along the seat rod. This dimensional change allows the chair to achieve a more compact folded height while maintaining structural simplicity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 frame remains compact and small in size when folded, facilitating easier storage and transportation without increasing in height or length, ensuring efficient space utilization.

Implementation Method 1

a rear end of each seat rod pivotally connected to a corresponding front leg of the leg frame, and a lower end of each backrest rod pivotally connected to a corresponding rear leg of the leg frame

Methodology Applied

Scientific EffectRotation:

Implementation Method 2

lower ends of the left and right upright poles are movably and respectively connected to the corresponding front legs

Methodology Applied

Scientific EffectMovable connection:

Data Source

PatentUS10206510B2Folding chair

Publication Date: 2019.02.19 CAMPVALLEY XIAMEN LEISURE PRODS

AI summary

A folding chair includes a chair frame. The frame includes left and right side stands, front and rear cross supporting rod assemblies, seat rods, backrest rods and left and right side upright poles. Each side stand includes a front leg that leans backward and a rear leg that is coupled to the front leg and supports the front leg. The front or rear cross supporting rod assembly includes two front cross supporting rods. The seat rods are connected to the front legs, rear legs and upright poles. The backrest rods are connected to the rear legs. The upright poles are movably connected to the front legs.