Ratchet Wheel Adjustment Mechanism for Thin HMD Headband Locking

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Solution Overview

Problem

Existing adjustment devices for head-mounted display devices often increase the weight and thickness due to complex gear assemblies used for tightness adjustment and locking, making them cumbersome and less suitable for wearable applications.

Innovation Solution

A compact adjustment device featuring a ratchet wheel assembly with a pawl and a fixing rod that allows for rotatable and locked states without increasing the overall structure thickness, utilizing a simpler mechanism for intuitive and convenient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If complex gear assemblies are used for tightness adjustment and locking, then the adjustment function is achieved, but the weight and thickness of the device increase

Engineering Contradiction:
Improvetightness adjustment and locking functionVSAvoiddevice weight
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The patent extracts and eliminates complex gear assemblies from the adjustment device, replacing them with a simplified ratchet wheel mechanism. The ratchet wheel assembly with pawl and fixing rod provides the necessary adjustment and locking functions without the weight and complexity of traditional gear systems, directly resolving the contradiction between operational functionality and device weight.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the mechanical parameter approach from complex multi-gear transmissions to a simple ratchet mechanism with direct engagement. This parameter change in the mechanical transmission system reduces the number of moving parts and overall weight while maintaining the adjustment and locking capabilities through the ratchet teeth and pawl engagement.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If complex gear assemblies are used for tightness adjustment and locking, then the adjustment function is achieved, but the structure becomes larger and thicker

Engineering Contradiction:
Improvetightness adjustment and locking functionVSAvoiddevice thickness
Core Design Contradiction:
Ease of operationVSLength of stationary object

Solution Approach 1:

The patent removes complex gear assemblies that contribute to device thickness and replaces them with a compact ratchet wheel assembly. The ratchet mechanism achieves the same adjustment and locking functions in a more space-efficient manner, reducing the overall thickness of the device while maintaining operational capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The ratchet wheel assembly is designed to be rotatably accommodated within the base structure, with the pawl and fixing rod nested within the ratchet wheel assembly. This nested arrangement allows the adjustment mechanism to be compact and integrated into the device without increasing overall thickness.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Reliability

If tight fittings are used to achieve limiting and fixing, then the locking function is achieved, but the structure becomes larger and more complex

Engineering Contradiction:
Improvelocking functionVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates tight fittings from the design, replacing them with a ratchet wheel mechanism that provides reliable locking through the engagement of the pawl with ratchet teeth. This extraction of unnecessary components simplifies the overall structure while maintaining the reliability of the locking function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The ratchet wheel mechanism provides self-locking capability through the geometric arrangement of ratchet teeth and the pawl. Once the fixing rod is rotated to the desired position, the pawl automatically engages with the ratchet teeth to maintain the locking state without requiring additional tight fittings or complex securing mechanisms, thus simplifying the structure while ensuring reliability.

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 enables efficient adjustment and locking of the device without adding bulk, providing a more intuitive and convenient user experience while maintaining structural integrity and reducing weight.

Implementation Method 1

The elastic arm is arranged on a side of the body and includes a first connecting segment and a second connecting segment that are connected. The first connecting segment is connected to the body. The second connecting segment is connected to the pawl

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4226802A1Adjustment device
Publication Date: 2023.08.16 PEGATRON
  • EP4226802A1 patent drawingFigure 1
  • EP4226802A1 patent drawingFigure 2
  • EP4226802A1 patent drawingFigure 3

AI summary

An adjustment device (100) includes a base (10), a ratchet wheel assembly (20) and a fixing rod (40). The base (10) includes an accommodating groove (11) and ratchet teeth (12). The ratchet wheel assembly (20) is rotatably accommodated in the accommodating groove (11) and includes a body (21), an elastic arm (22), and a pawl (23). The elastic arm (22) includes a first connecting segment (221) connected to the body (21) and a second connecting segment (222) connected to the pawl (23). The pawl (23) may engage with one of the ratchet teeth (12). The fixing rod (40) movably extends between the body (21) and the elastic arm (22). When the fixing rod (40) is arranged between the second connecting segment (222) and the body (21), the pawl (23) is fixed to the ratchet teeth (12), so that the ratchet wheel assembly (20) is positioned on the base (10). When the fixing rod (40) is arranged between the first connecting segment (221) and the body (21), the ratchet wheel assembly (20) may rotate relative to the base (10).