Multi-Pivot Safety Razor Blade Unit with Magnetic Return

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Safety razors with blades mounted for pivotal movement about a single axis parallel to the cutting edges have limited ability to conform to skin contours, often disengaging during shaving due to restricted pivot range.

Innovation Solution

Employing a magnetic return force about a pivot axis substantially perpendicular to the blade edges, with sets of magnetic elements generating increasing repulsive forces to maintain consistent and smooth pivotal movement, allowing the blade unit to follow skin contours effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single pivot axis parallel to blade edges is used, then the structure is simple, but the blade unit has limited ability to conform to skin contours

Engineering Contradiction:

Improvepivot structureVSAvoidconformance to skin contours

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The pivot structure is segmented into two independent axes: a first pivot axis substantially parallel to the blade cutting edges, and a second pivot axis substantially perpendicular to the blade cutting edges. This segmentation allows each axis to independently contribute to blade unit movement, enabling the blade unit to conform to complex skin contours that cannot be achieved with a single pivot axis alone.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If magnetic return force is applied, then smooth and reproducible pivotal movement is achieved, but the device complexity increases

Engineering Contradiction:

Improvepivotal movement smoothnessVSAvoidmagnetic element configuration

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

Traditional mechanical return springs are replaced with magnetic return forces generated by magnetic elements. The magnetic elements are positioned on the handle and blade unit assembly such that their magnetic interaction provides a return force that increases as the blade unit pivots away from its rest position. This substitution eliminates the need for physical springs while achieving smooth, reproducible pivotal movement through magnetic field interactions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Ensures smooth and reproducible pivotal movement, improving conformance with skin contours and reducing disengagement during shaving, with adjustable return force strength via magnetic element configuration.

Implementation Method 1

The return force comprises a magnetic force generated by a set of magnetic elements that are moved relative to each other in response to pivotal movement of the blade unit about the pivot axis substantially perpendicular to the at least one blade

Methodology Applied

Scientific EffectMagnetic force: Magnetism

Data Source

PatentUS7913393B2Safety razor with multi-pivot blade unit

Publication Date: 2011.03.29 THE GILLETTE CO

AI summary

A safety razor blade unit mounted for pivotal movement relative to a razor handle about a pivot axis substantially perpendicular to a blade mounted in the blade unit. The blade unit is biased to a rest position by a magnetic return force generated by a set of magnetic elements. The set of magnetic elements are so disposed that the return force increases as the pivotal displacement of the blade unit from the rest position increases.