Headrest Limiting Convex Block Design to Reduce Repeated-Use Damage

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Solution Overview

Problem

Conventional headrest devices have a complex and weak limiting structure that is prone to damage from repeated use, leading to reliability issues and safety risks due to insufficient strength and complex assembly processes.

Innovation Solution

A headrest device with a support frame and a limiting convex block that smoothly stops the headrest component's rotation using a cambered and abutting surface contact, combined with a reset member for reliable operation, and an adjustable position to enhance durability and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional limiting structure is used to limit motion range and limiting position, then the headrest device can be controlled to stop at specific positions, but the structure becomes complex and prone to damage from repeated use

Engineering Contradiction:

Improvereliability of limiting structureVSAvoidcomplexity of limiting structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The limiting structure is segmented into a fixed limiting convex block on the support frame and a movable limiting convex portion on the headrest component. This segmentation allows the fixed part to provide stable positioning while the movable part absorbs impact forces, resolving the contradiction between reliability and complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The limiting convex portion on the headrest component is designed to contact the limiting convex block beforehand during rotation, cushioning the impact before it reaches the fixed structure. This prior cushioning prevents damage from repeated use while maintaining a simple overall structure.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Strength

If a complex limiting structure is used to ensure strength, then the headrest device can withstand repeated use, but the assembly process becomes inconvenient

Engineering Contradiction:

Improvestrength of limiting structureVSAvoidease of assembly

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The limiting structure is divided into separately manufacturable components: a limiting convex block that can be directly formed on the support frame and a limiting convex portion on the headrest component. This segmentation enables simple individual manufacturing while achieving strong combined strength through their interaction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of making the support frame complex to provide the limiting function, the invention inverts the approach by adding a simple limiting convex portion to the headrest component that interacts with a simple convex block on the frame. This inversion simplifies both manufacturing and assembly while maintaining strength.

Inventive Principle:

Principle #13The other way round (Inversion)

3Adaptability or versatility

If the headrest component reciprocates repeatedly, then the adjustment function is useful, but the limiting structure becomes damaged or fails

Engineering Contradiction:

Improveadjustment functionVSAvoiddurability of limiting structure

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The limiting convex portion on the headrest component serves as a cushioning element that contacts the limiting convex block before impact occurs during reciprocating movements. This beforehand cushioning protects the limiting structure from damage while allowing repeated adjustment operations.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The invention changes the physical parameters of the limiting structure by using curved limiting convex portions instead of sharp edges, and by positioning them to engage gradually during rotation. This parameter change allows the structure to withstand repeated reciprocating movements without fatigue damage.

Inventive Principle:

Principle #35Parameter changes

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 stable and safe lifting support for the head, prevents damage to the limiting convex block, simplifies the structure and assembly, and reduces production costs while maintaining reliability and comfort.

Implementation Method 1

the first connecting portion is provided with a cambered surface configured to slide contact with the limiting convex block... the first connecting portion and the limiting convex block can move relative to each other and smoothly with low resistance

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

the second connecting portion is provided with an abutting surface and the headrest component is in contact with the limiting convex block by the abutting surface in the initial limiting position

Methodology Applied

Scientific EffectImpact Force: Impact Force

Data Source

PatentUS11602224B2Headrest device and chair having the same

Publication Date: 2023.03.14 ZHANG XIAOZHAO

AI summary

A headrest device and a chair having the same are provided. The headrest device includes a support frame, a headrest component and a reset member. The support frame is pivotally connected with the headrest component, and the reset member is connected with the headrest component and configured to drive the headrest component to rotate relative to the support frame. The support frame is provided with a limiting convex block, and the limiting convex block can stop a rotation of the headrest component when the headrest component moves to an initial limiting position.