Tool-Free Backrest Locking for Detachable Office Chair Assembly

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Solution Overview

Problem

Existing office chairs with backrests are bulky, difficult to assemble and disassemble, and require tools, making them challenging to handle and transport.

Innovation Solution

A detachable backrest support system that can be easily attached and detached from the seat support without tools, using a manually operable safety device with a helical compression spring and locking mechanism to secure the backrest in place, allowing for secure assembly and quick disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the backrest support is detachably connected to the seat support, then the ease of assembly and disassembly is improved, but the reliability of the connection may worsen

Engineering Contradiction:
Improveease of assembly and disassemblyVSAvoidconnection reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The backrest support is divided into a separate detachable component from the seat support, allowing independent assembly and disassembly. The backrest support can be inserted into and removed from the seat support receptacle without tools, while maintaining stable connection during use through the locking mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The safety device is pre-configured in the seat support with a manually operable release mechanism. The user only needs to perform a simple manual action (actuating the safety device) to release the locking mechanism, rather than requiring tools or complex disassembly procedures.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If a manually operable safety device with locking mechanism is used, then the stability of the backrest support is improved, but the device complexity increases

Engineering Contradiction:
Improvebackrest support stabilityVSAvoidconnection mechanism complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The safety device automatically locks the backrest support in place upon insertion, without requiring additional fastening actions. The manually operable safety device serves dual purposes: it maintains stable locking during normal use and provides simple one-handed release when activation is needed.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If the backrest support is made detachable, then the ease of transportation is improved, but the ease of manufacture may worsen

Engineering Contradiction:
Improveease of transportationVSAvoidmanufacturing complexity
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The backrest support is designed to nest within or attach to the seat support structure when not in use, and can be completely detached for compact transportation. The receptacle in the seat support provides a designated storage position for the backrest support when removed from the chair.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

Enables easy and tool-free assembly and disassembly of the backrest support, preventing wobbling and facilitating space-saving transportation of the chair.

Implementation Method 1

using a manually operable safety device with a helical compression spring and locking mechanism to secure the backrest in place

Methodology Applied
Scientific EffectHelical compression spring: Spring

Data Source

PatentEP2298133B1Chair
Publication Date: 2012.03.14 DAUPHIN ENTWICKLUNGS U BETEILIGUNGS GMBH
  • EP2298133B1 patent drawingFigure 1
  • EP2298133B1 patent drawingFigure 2
  • EP2298133B1 patent drawingFigure 3

AI summary

The chair has a foot frame for support with respect to the ground, where the foot frame is connected to a seat support (5). A seat is arranged on the seat support. A rear leaning carrier (7) is supported at a back-rest, and is connected to the seat support in a detachable manner.