Spring Back Hinge Assembly for Adjustable Chair Rocking

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Solution Overview

Problem

Existing backrest adjustment systems lack flexibility and adaptability, failing to provide a comfortable 'rocking' mechanism that can be adjusted to user preference and are not easily compatible with various furniture configurations.

Innovation Solution

A spring back hinge assembly with an optional spring lock mechanism, allowing for mechanical adjustment of tension and enabling the backrest to rock independently of a fixed seat frame, while also providing a means to fix the backrest position, which can be easily integrated with different seat and armrest profiles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a fixed seat frame is used, then structural stability is improved, but the ability to provide a rocking mechanism is lost

Engineering Contradiction:

Improvestructural stabilityVSAvoidrocking mechanism capability

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The seat assembly is divided into separate functional modules: a fixed seat frame, a movable backrest frame, and a spring hinge assembly connecting them. This segmentation allows the backrest to rock independently while the seat frame remains stable.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The spring hinge assembly introduces dynamic capability to the otherwise fixed structure. The spring mechanism allows controlled movement and rocking of the backrest while maintaining overall structural integrity through elastic deformation.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If a spring back hinge is added to enable rocking, then adaptability and user comfort are improved, but device complexity increases

Engineering Contradiction:

Improverocking mechanism capabilityVSAvoidnumber of components

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The spring hinge assembly combines multiple functions into a single integrated component: it serves as both the connection joint between seat and backrest, and as the spring mechanism enabling rocking motion. This merging reduces the number of separate parts needed.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The spring hinge assembly performs multiple functions simultaneously: structural connection, enabling rocking motion, providing tension adjustment, and supporting the backrest weight. This multi-functionality reduces overall system complexity despite adding capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If tension adjustment mechanism is added, then user comfort and preference adaptability are improved, but ease of manufacture deteriorates

Engineering Contradiction:

Improvetension adjustment capabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The spring hinge assembly allows tension adjustment by changing the pre-compression or pre-tension of the spring mechanism. This parameter adjustment provides customizable rocking resistance without requiring complex mechanical systems, maintaining ease of manufacture.

Inventive Principle:

Principle #35Parameter changes

4Stability of the object's composition

If a spring lock mechanism is added to fix backrest position, then stability in sitting position is improved, but device complexity increases

Engineering Contradiction:

Improvebackrest position stabilityVSAvoidmechanism complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The spring lock mechanism utilizes the existing spring force and gravitational force to automatically lock and unlock the backrest position. The mechanism self-regulates without requiring additional power sources or complex control systems, minimizing added complexity while providing stable position locking.

Inventive Principle:

Principle #25Self-service

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 solution provides a comfortable and adaptable 'rocking' mechanism that can be adjusted to user preference, improving furniture compatibility and reducing the number of variable parts required, thus enhancing performance and usability.

Implementation Method 1

The spring back hinge is mounted on a left, right or both left and right side of a backrest frame that and provides spring in the back frame to allow a user to 'rock' the backrest fore and aft

Methodology Applied

Scientific EffectSpring: Spring

Implementation Method 2

The hinge allows for mechanical adjustment of the tension used in the flex of the back frame assembly allowing a softer or firmer 'ride' depending on the user's preference

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS9060610B2Spring back hinge with or without spring lock mechanism

Publication Date: 2015.06.23 FLEXSTEEL IND INC

AI summary

A spring back hinge interconnects a backrest frame to a chair seat frame or is mountable to just the chair base frame, the spring back hinge being optionally fittable with a lever actuated locking assembly and the spring back hinge being fittable on a single side or both sides, alternative back rest frames being fittable to the spring back hinge.