Electric Shaver Outer Blade Frame Stabilization

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Solution Overview

Problem

Conventional reciprocation type electric shavers experience wobbling of outer blades due to unstable fixation, leading to ineffective shaving and usability issues under external forces.

Innovation Solution

The design incorporates a frame holder with engaging rims and arms that securely attach to an outer blade mounting base, providing stable fixation and reinforcement to prevent wobbling, using a configuration of elongated outer blades and inner blades driven by a linear motor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the outer blade frame is held at only both side faces by the frame holder, then the frame holder structure is simple, but the outer blade becomes unstable and may wobble when large external force is applied

Engineering Contradiction:
Improveframe holder structureVSAvoidouter blade stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent transitions from holding the outer blade frame at only side faces (2D planar support) to adding end face support (3D volumetric enclosure). The frame holder now engages the outer blade frame at four locations: both side faces and both end faces, creating a three-dimensional stable structure that prevents wobbling while maintaining simplicity.

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

2Reliability

If the outer blade is held stable by adding more support points, then wobbling is prevented, but the frame holder structure becomes more complex

Engineering Contradiction:
Improveouter blade stabilityVSAvoidframe holder structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple support functions into a single integrated frame holder structure. The frame holder simultaneously provides side face support and end face support, merging what could have been separate support mechanisms into one unified component that achieves stable outer blade holding without increasing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2208590B1Electric shaver
Publication Date: 2013.12.25 PANASONIC HOLDINGS CORP
  • EP2208590B1 patent drawingFigure 1(a)~2
  • EP2208590B1 patent drawingFigure 3~4
  • EP2208590B1 patent drawingFigure 5~6

AI summary

In an electric shaver (1) moving inner blades (7) reciprocally and linearly, outer blades (3) which are elongated in longitudinal direction (X) are respectively held on outer blade frames (4) and the outer blade frames (4) are further held in floatable in floating direction (Z) on a frame holder (5). An outer blade mounting base (6) has a pair of protrusions (61) formed at positions near to both ends thereof in the longitudinal direction (X) to protrude in the floating direction (Z) and the frame holder (5) has a pair of end walls 5a arranged in parallel in the longitudinal direction (X) and a pair of engaging rims (51) formed at both ends in the longitudinal direction (X). The engaging rims (51) enclose the protrusions (61) so as to position the frame holder (5) to the outer blade mounting base (6) when the frame holder (5) is attached to the outer blade mounting base (6).