Cutting Height Dial Mechanism With Asymmetric Stepwise Engagement

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Solution Overview

Problem

Existing cutting devices, such as hair clippers, face challenges in improving the operability of the dial mechanism for adjusting cutting height, which is crucial for user convenience.

Innovation Solution

The cutting device incorporates a cutting height adjustment mechanism with a dial that includes a holding mechanism with releasable engagement parts featuring irregularly-shaped engagement recesses and protrusions, allowing for stepwise adjustments and reduced operational loads by varying the inclination angles and heights of these engagement features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional dial mechanism is used for cutting height adjustment, then the structure is simple, but the operability is poor due to large difference in required forces for rotation in different directions

Engineering Contradiction:
Improvedial operabilityVSAvoidholding mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The engagement part is designed with asymmetric geometry where the engagement recess and engagement protrusion have different shapes on opposite sides in the rotation direction. This asymmetry creates different inclination angles for engagement and disengagement, resulting in different required forces for rotating the dial in different directions, thereby improving operability by reducing the force difference between clockwise and counter-clockwise rotation.

Inventive Principle:
Principle #4Asymmetry

2Ease of operation

If the engagement part has symmetric shape, then the manufacturing is easy, but the operability is reduced due to equal required forces in both rotation directions

Engineering Contradiction:
Improvedial adjustment easeVSAvoidengagement part manufacturing
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The engagement part employs asymmetric geometry with different shapes on either side of the rotation direction. This design intentionally creates manufacturing complexity to achieve superior operability, where the asymmetric profile allows the dial to rotate more easily in one direction while providing controlled resistance in the opposite direction, enhancing user experience despite increased manufacturing难度.

Inventive Principle:
Principle #4Asymmetry

3Reliability

If a simple engagement mechanism is used, then the device complexity is low, but the stepwise holding function is insufficient

Engineering Contradiction:
Improvestepwise holding reliabilityVSAvoidholding mechanism structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The engagement mechanism is segmented into distinct engagement recesses and engagement protrusions that interact to create discrete stepwise positions. This segmentation allows the dial to be held reliably at specific intervals during rotation, providing precise cutting height adjustments while maintaining a relatively simple overall structure through the modular nature of the engagement elements.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4484090B1Cutting device
Publication Date: 2026.02.18 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP4484090B1 patent drawingFigure 1
  • EP4484090B1 patent drawingFigure 2
  • EP4484090B1 patent drawingFigure 3

AI summary

The present disclosure provides a cutting device capable of further improving operability of a dial. A cutting device according to the present disclosure includes a main body, a fixed blade fixed to the main body, and a movable blade capable of reciprocating in a slidable way with respect to the fixed blade. Furthermore, the cutting device includes a cutting height adjustment mechanism that includes a dial rotatably attached to the main body and is capable of adjusting a cutting height by rotating the dial. The cutting height adjustment mechanism includes a holding mechanism capable of holding the dial in a stepwise manner, and the holding mechanism includes a recess and a protrusion part that are releasably engaged with each other. At least one of the recess and the protrusion part includes an irregularly-shaped engagement part having a different shape on one side and the other side in a rotation direction of the dial.