Backrest Height Adjusting Assembly

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Solution Overview

Problem

Existing backrest height adjustment mechanisms are cumbersome and unreliable, failing to provide consistent comfort for users of varying heights and often result in the backrest loosening over time.

Innovation Solution

A backrest height adjusting device featuring a fixing seat with vertical posts and coupling sleeves, an adjusting mechanism with gears, a movable block, and an elastic element that allows for easy height adjustment and secure retention of the backrest at a selected height, along with a waist rest mechanism for customizable support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a knob is used to tighten and fix the backrest height, then the backrest can be adjusted to different heights, but the adjusting procedure becomes troublesome and the backrest may loosen if the knob is not tightened

Engineering Contradiction:

Improvebackrest height adjustmentVSAvoidadjusting procedure

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The lever mechanism automatically engages with the positioning grooves through its own movement, eliminating the need for separate tightening operations. When the lever is moved to a positioned state, it automatically locks the backrest at the selected height, and when moved to a releasing state, it automatically allows height adjustment.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The traditional knob-based mechanical tightening system is replaced with a lever-based mechanical system that uses rotational movement to engage/disengage positioning elements, providing a more intuitive and easier operating mechanism.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If a knob is used to fix the backrest height, then height adjustment is possible, but the positioning effect becomes unreliable and the backrest may loosen

Engineering Contradiction:

Improvebackrest height adjustmentVSAvoidpositioning effect

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The positioning system is segmented into multiple positioning grooves at different heights, with the lever having corresponding positioning elements that engage with these grooves. This segmentation allows for discrete, reliable positioning at multiple predetermined heights, preventing the backrest from loosening between positions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The positioning grooves are pre-formed in the fixing seat at specific heights, and the lever is designed with corresponding engagement elements that automatically align with these pre-positioned grooves, ensuring reliable positioning before any load is applied.

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If the backrest contour is fixed to match human body curvature, then lying comfort is improved, but the design cannot suit different users of different heights

Engineering Contradiction:

Improvelying comfortVSAvoiduser height accommodation

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The backrest is designed with dynamic height adjustability, allowing the contour to be repositioned vertically to accommodate users of different heights. The lever mechanism enables the backrest to be moved between multiple fixed height positions, maintaining the ergonomic contour shape while adapting to different user requirements.

Inventive Principle:

Principle #15Dynamics

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, reliable, and customizable height adjustment of the backrest and waist rest, providing improved comfort and stability by ensuring the backrest remains securely positioned and allowing for various height settings to accommodate different users.

Implementation Method 1

The elastic element biases the movable block to move relative to the fixing block and biases the toothed portion of the movable block to mesh with the at least one gear to retain the backrest in a selected height relative to the fixing seat

Methodology Applied

Scientific EffectElastic element biasing: Elasticity

Data Source

PatentUS20190350367A1Backrest Height Adjusting Assembly

Publication Date: 2019.11.21 WANG CHIH JEN

AI summary

A backrest height adjusting device includes a fixing seat fixed in relation to a chair seat and having at least one fixing post. A backrest includes at least one coupling sleeve coupled with the at least one fixing post. At least one gear is rotatably mounted to the fixing block fixed on the backrest and is coupled with a plurality of positioning grooves on the at least one fixing post. An elastic element biases a movable block to move relative to the fixing block in a vertical direction and biases the movable block to mesh with the at least one gear to retain the backrest in a selected height relative to the fixing seat. The movable block is actuatable to disengage from the plurality of teeth of the at least one gear to thereby permit the backrest to move in the vertical direction relative to the fixing seat.