Pivoting Razor Cartridge Coupling With Protected Handle Interface

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Solution Overview

Problem

Existing razor assemblies face issues with the exposure of coupling portions leading to deformation or damage, improper coupling, difficulty in recognizing the coupling direction, and unintended detachment during shaving, which affect shaving performance and convenience.

Innovation Solution

A razor assembly design featuring a razor handle with a coupling portion covered by a restoring force providing portion, a connector on the razor cartridge, and a pivotable blade housing with a cam support for easy alignment and secure attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the coupling portion is exposed to the outside for easy coupling, then the coupling operation is convenient, but the coupling portion becomes vulnerable to external impact and deformation

Engineering Contradiction:
Improvecoupling operation convenienceVSAvoidexternal impact on coupling portion
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The coupling portion is nested within the blade housing structure, which serves as a protective outer shell. The blade housing accommodates the coupling portion internally, allowing the coupling to be performed while remaining protected from external impacts, thus resolving the contradiction between accessibility and protection.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The blade housing acts as an intermediary structure between the external environment and the coupling portion. It provides a protected interface for coupling operations, allowing users to couple the razor cartridge to the handle without directly exposing the fragile coupling portion to external forces.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the coupling portion structure is simplified for easy manufacturing, then manufacturing cost decreases, but coupling precision and alignment become difficult

Engineering Contradiction:
Improvecoupling portion manufacturingVSAvoidcoupling alignment precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The coupling portion employs an asymmetric structure with a specific geometric configuration that provides inherent alignment guidance. The asymmetric shape ensures proper orientation during coupling while maintaining manufacturability through standard machining processes, balancing manufacturing simplicity with coupling precision.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The coupling portion features localized precision elements (such as specific surface finishes or geometric features) only at critical coupling areas, while other portions of the structure maintain standard manufacturing tolerances. This approach ensures high coupling precision where needed without unnecessarily increasing overall manufacturing complexity.

Inventive Principle:
Principle #3Local quality

3Strength

If the blade housing is made rigid for stability, then structural strength increases, but pivoting motion and adaptability to skin contours are reduced

Engineering Contradiction:
Improveblade housing structural strengthVSAvoidpivoting motion capability
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The razor assembly is segmented into the rigid blade housing and the flexible pivoting connection mechanism. The blade housing itself remains rigid for strength, while the connection to the handle allows pivoting motion, separating the structural strength function from the adaptability function and resolving the contradiction between rigidity and flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The blade housing maintains its rigid structure for strength, but the coupling mechanism incorporates dynamic pivoting capability that allows the blade housing to rotate and adapt to skin contours during use. This dynamic element is introduced at the connection point rather than compromising the blade housing rigidity.

Inventive Principle:
Principle #15Dynamics

4Loss of information

If the coupling portion is exposed for visual recognition of coupling direction, then user recognition improves, but vulnerability to damage increases

Engineering Contradiction:
Improvecoupling direction recognitionVSAvoidcoupling portion durability
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The blade housing or coupling interface incorporates visual indicators (such as color coding, markings, or asymmetric patterns) that are visible through or around the protected coupling area. These indicators provide coupling direction recognition without requiring the coupling portion itself to be exposed, maintaining both visibility and protection.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The visual indicators for coupling direction are positioned in a different spatial dimension or location relative to the coupling portion - such as on the outer surface of the blade housing or on adjacent surfaces - allowing users to recognize the correct coupling orientation without the coupling portion being directly exposed to external forces.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 design protects the coupling portion from external impacts, facilitates easy and accurate coupling, reduces unintended detachment, and enhances shaving performance and convenience by maintaining a lower resting angle.

Implementation Method 1

a restoring force providing portion configured to provide a restoring force against pivoting of the blade housing

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP4691718A1Razor assembly
Publication Date: 2026.02.11 DORCO CO LTD
  • EP4691718A1 patent drawingFigure 1
  • EP4691718A1 patent drawingFigure 2
  • EP4691718A1 patent drawingFigure 3

AI summary

A razor assembly according to an embodiment of the present invention comprises: at least one blade having a cutting edge; a blade housing longitudinally accommodating the at least one blade; a connector located on one side of the blade housing; a razor handle connected to the blade housing so that the blade housing can rotate, the razor handle including a coupling portion coupled to the connector; and a restoring force-providing member configured to provide a restoring force with respect to the rotation of the blade housing, the restoring force-providing member configured to cover at least a portion of the coupling portion from above the coupling portion.