Shaving Razor Biasing Member for Flat Skin Contact

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Solution Overview

Problem

Conventional shaving razors often fail to maintain the blade unit flat against the skin during shaving, leading to instability and reduced shaving closeness due to limited pivotability and handle geometry issues, which affect glide and comfort.

Innovation Solution

A shaving razor design featuring a biasing member that produces a progressively increasing return torque to force the cartridge into flat contact with the skin, combined with a handle configuration that improves stability and control by balancing the load distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the blade unit is designed with limited pivotability about a single axis, then the device complexity is reduced, but the blade unit fails to remain flat against the skin during shaving

Engineering Contradiction:
Improvepivot mechanism complexityVSAvoidblade unit flatness against skin
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The blade unit is designed with dynamic pivotability about two axes: a primary pivot axis allowing rotation during shaving strokes, and a secondary axis allowing the blade unit to rock or tilt. This dual-axis dynamic capability enables the blade unit to adapt to skin contours while maintaining flat contact, resolving the contradiction between simple mechanism design and stable blade-skin contact.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the handle longitudinal axis is offset from the razor cartridge behind the cartridge, then the cartridge is pushed through the shaving stroke, but it becomes difficult to maneuver and requires a steady hand

Engineering Contradiction:
Improveshaving stroke efficiencyVSAvoidrazor maneuverability
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The handle configuration employs asymmetric positioning where the longitudinal axis is offset from the cartridge centerline, creating a deliberate imbalance that generates rotational torque during shaving. This asymmetric design provides automatic steering capability, allowing the razor to follow skin contours without requiring precise manual control, thus improving both maneuverability and shaving efficiency.

Inventive Principle:
Principle #4Asymmetry

3Device complexity

If the handle longitudinal axis extends above the axis of roll, then the handle configuration is simplified, but instability is introduced during shaving similar to a top heavy scenario

Engineering Contradiction:
Improvehandle configuration simplicityVSAvoidrazor stability during shaving
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The handle design incorporates counterbalancing elements positioned to offset the top-heavy effect caused by the longitudinal axis extending above the roll axis. This counterweight arrangement creates a balanced center of gravity that prevents unwanted rotation and rolling during shaving, maintaining stability while preserving the simplified handle configuration.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

4Manufacturing precision

If a spring is used to reduce the cartridge to skin angle, then shaving closeness is improved, but the cartridge may lift off the skin during shaving strokes

Engineering Contradiction:
Improvecartridge to skin angle precisionVSAvoidcartridge contact consistency
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The spring mechanism is designed with dynamic characteristics that allow it to flex and adapt during shaving strokes. The spring provides sufficient force to maintain the optimal cartridge-to-skin angle for close shaving, while its elastic properties enable it to absorb variations in shaving pressure and skin contour, preventing cartridge lift-off and ensuring consistent contact throughout the shaving stroke.

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

The solution ensures a closer, more stable, and comfortable shave by minimizing the cartridge-to-skin angle and reducing the propensity for the razor to roll or spin, enhancing user control and shaving efficiency.

Implementation Method 1

a shaving razor including a biasing member producing a progressively increasing return torque that forces the cartridge into flat contact with the skin as the cartridge pivots

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP2629942B1Shaving razor including a biasing member producing a progressively increasing cartridge return torque
Publication Date: 2019.07.10 THE GILLETTE CO
  • EP2629942B1 patent drawingFigure 1
  • EP2629942B1 patent drawingFigure 2A~2B
  • EP2629942B1 patent drawingFigure 3

AI summary

A shaving razor that offers a closer shave is provided. The shaving razor can include a biasing member producing a progressively increasing return torque on the razor cartridge that forces the cartridge into flat contact with the skin as the cartridge pivots, thus improving glide and shaving closeness. In addition, the shaving razor can include a razor handle configuration that reduces the propensity for the shaving razor to roll in a user's hand and improves the maneuverability of the razor cartridge during shaving.