Electric Shaver Four-Joint Linkage for Balanced Weight Distribution

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Solution Overview

Problem

Existing electric shavers face challenges in self-adjusting their angular position to skin contours without restricting the drive train or support structure kinematics, leading to top-heavy weight distribution, reduced handling comfort, and inefficiencies in cutter element movement.

Innovation Solution

A four-joint linkage with link arms configured in a standing arrangement, allowing the shaver head to swivel and tilt while maintaining a balanced design by positioning the electric motor within the handle, and using a double pitch roof-like trajectory for the virtual center point of the shaver head to reduce friction and improve kinematics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the motor is positioned in the shaver head to drive cutter elements, then the drive train can be compact, but the shaver becomes top-heavy and handling comfort is reduced

Engineering Contradiction:

Improvedrive train configurationVSAvoidhandling comfort

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The motor is inverted from the conventional position in the shaver head to the handle portion. This inversion relocates the heavy component to achieve balanced weight distribution while maintaining compact drive train functionality through the elongated drive transmitter that extends from the handle to the cutter element

Inventive Principle:

Principle #13The other way round (Inversion)

2Adaptability or versatility

If the shaver head is allowed to swivel and tilt freely to adapt to skin contours, then adaptability is improved, but the support structure becomes complex and may collide with the drive train

Engineering Contradiction:

Improveskin contour adaptationVSAvoidsupport structure configuration

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The support structure is segmented into distinct functional components: a swivel mechanism allowing rotation about a longitudinal axis, and a tilting mechanism allowing angular adjustment about a transverse axis. This segmentation enables independent control of each degree of freedom, reducing overall complexity while achieving full adaptability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An intermediary mechanism is introduced between the handle and shaver head that mediates the movement transmission. This intermediary support structure with separate swivel and tilting joints allows the shaver head to adapt to skin contours while preventing collision with the drive train by decoupling the motion paths

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If the link arms are arranged in a hanging configuration, then the four-joint linkage can be implemented, but the shaver head movements are restricted and handling is less comfortable

Engineering Contradiction:

Improvefour-joint linkage implementationVSAvoidshaver head responsiveness

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The link arms are inverted from a hanging configuration (extending downward from the handle) to a standing configuration (extending upward from the handle toward the shaver head). This inversion improves the mechanical advantage and responsiveness of the shaver head movements, making the device more comfortable to handle while maintaining the four-joint linkage functionality

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS10960557B2Electric shaver with four joint linkage

Publication Date: 2021.03.30 BRAUN GMBH

AI summary

Electric shaver provided with a handle and a shaver head including at least one drivable cutter element, wherein said shaver head is connected to said handle by means of a support structure providing for a swivel and/or tilting axis about which said shaver head may swivel or tilt relative to said handle, wherein said support structure includes a pair of link arms forming a four-joint linkage with each link arm having a head joint connected to a shaver head part and a handle joint connected to the handle or a base part connected thereto.