Angle adjustment metal fitting and legless chair and sofa using same

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Solution Overview

Problem

Conventional angle adjustment metal fittings for legless chairs require cumbersome operations to adjust the inclined angle of the backrest plate, especially when there is limited space between the backrest and a wall surface, as they need to be tilted to the horizontal position.

Innovation Solution

An angle adjustment metal fitting with a first member, a second member, a claw member, a spring member, and a claw control member, allowing for angle adjustment without unfolding to the horizontal position by utilizing a gear and toothed surface mechanism that enables relative rotation in multiple directions, ensuring usability even in confined spaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the composition frame B is tilted to the horizontal position and then raised to adjust the inclined angle, then the angle can be adjusted, but the operation becomes cumbersome and cannot be adjusted when there is not enough space between the composition frame B and the wall surface

Engineering Contradiction:

Improveease of angle adjustmentVSAvoidadaptability to confined spaces

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent inverts the conventional adjustment sequence by allowing the composition frame B to rotate directly to the desired angle without first tilting to horizontal. The ratchet mechanism is designed to engage during the rotation process itself, rather than requiring the frame to be positioned horizontally first. This inversion of the adjustment sequence eliminates the cumbersome two-step operation and enables angle adjustment in confined spaces where horizontal positioning is not feasible.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent implements a dynamic adjustment mechanism where the ratchet teeth and pawl engage during the rotation process itself, allowing continuous angle adjustment. The ratchet teeth are arranged on the composition frame B such that they engage with the pawl at various angular positions during rotation, enabling the frame to be held at any desired angle without requiring it to return to a horizontal position. This dynamic engagement provides flexibility and adaptability to confined spaces.

Inventive Principle:

Principle #15Dynamics

2Area of stationary object

If the composition frame B is arranged close to the wall surface, then space is saved, but the inclined angle cannot be adjusted due to insufficient space

Engineering Contradiction:

Improvespace utilizationVSAvoidease of angle adjustment

Core Design Contradiction:

Area of stationary objectVSEase of operation

Solution Approach 1:

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent utilizes the rotational dimension of the composition frame B to achieve angle adjustment without requiring linear space for horizontal positioning. By designing the ratchet mechanism to engage during rotation rather than at a fixed horizontal position, the invention transforms the adjustment process from a two-dimensional horizontal-then-vertical sequence into a direct rotational movement, enabling operation in confined spaces where only limited angular movement is available.

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

Enables easy adjustment of the unfolded angle without tilting to the horizontal position, providing high usability and stable operation characteristics, even when space is limited, such as near a wall surface.

Implementation Method 1

a spring member 40 that is attached in the first member 10 and applies biasing force for rotating the claw member 30 toward the second member 20

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a meshing state between the gear portion 26 of the second member 20 and the toothed surface 35 of the claw member 30

Methodology Applied

Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentEP3991602B1Angle adjustment metal fitting and legless chair and sofa using same

Publication Date: 2023.06.28 KOYO GIKEN KK

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AI summary

An object is to provide an angle adjustment metal fitting enabling an angle to be adjusted without unfolding two unfoldable components to the horizontal position. A claw control member (60) has a position restricted so as not to rotate together while a second member (20) relatively rotates in a folding direction, and a meshing state between a gear portion (26) of a second member (20) and a toothed surface (35) of a claw member (30) is released. While the second member (20) then relatively rotates in an unfolding direction, the toothed surface (35) of the claw member (30) has a position restricted so as not to mesh with the gear portion (26) of the second member (20). When the second member (20) is then operated to be relatively rotated by a predetermined small angle in the folding direction, the toothed surface (35) of the claw member (30) mesh with the gear portion (26) of the second member (20) to restrict the relative rotation of the second member (20) in the unfolding direction.