Multi-blade Razor Head with Variable Spring Biasing
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Solution Overview
Problem
Conventional shaving razors often cause skin irritation and uneven force distribution during shaving due to aggressive blade edges and uniform spring force across all blades, leading to unpleasant shaving experiences.
Innovation Solution
A razor head design featuring movable blades with adjustable spring force, where cantilever springs provide softer springs for blades between the guard bar and pivot axis and stiffer springs for blades between the pivot axis and cap, allowing for modified shaving geometry and even force distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform spring force is applied to all blades, then the structure is simple and easy to manufacture, but the force distribution becomes uneven and causes skin irritation
Solution Approach 1:
The patent applies different spring forces to different blades based on their position. Blades closer to the pivot axis (which experience more user pressure) are assigned softer springs, while blades farther from the pivot axis are assigned stiffer springs. This local differentiation of spring properties compensates for the non-uniform pressure distribution during shaving, reducing skin irritation without requiring complex overall restructuring.
2Ease of operation
If movable blades with uniform spring force are used, then the blades can compensate for pressure, but dragging forces occur due to improper force distribution
Solution Approach 1:
The patent implements position-dependent spring forces where blades near the pivot axis have softer springs and blades farther away have stiffer springs. This local quality variation ensures that each blade experiences appropriate force compensation during shaving, allowing smooth blade movement without excessive dragging forces that would occur with uniform spring force distribution.
3Productivity
If pressure is applied at the pivot axis point, then the shaving action is effective, but the blade edges become too aggressive and cause irritation
Solution Approach 1:
The patent addresses the aggressive blade edges caused by pivot-axis pressure application by assigning softer springs to blades located near the pivot axis. This local softening compensates for the concentrated pressure at these positions, reducing the aggressiveness of the blade edges while maintaining effective shaving action where it is most needed.
Solution Approach 2:
The patent changes the spring force parameter based on blade position relative to the pivot axis. By varying the spring constant (stiffness) of each blade's spring according to its location, the system dynamically adjusts the effective blade pressure during shaving, reducing irritation caused by excessive force at the pivot axis while preserving shaving effectiveness.
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
This design reduces skin irritation and dragging forces, providing a more fluid shave by compensating for user pressure and distributing forces more evenly across the blades.
Implementation Method 1
each blade of the plurality of blades is biased toward a shaving plane, at least in part, by at least one of the plurality of resilient members
Implementation Method 2
a plurality of resilient members, wherein each blade of the plurality of blades is biased toward a shaving plane, at least in part, by at least one of the plurality of resilient members
Data Source
AI summary
A razor head for shaving is provided. The razor head includes a plurality of blades movably mounted within a support and a plurality of resilient members, wherein each blades of the plurality of blades is biased toward a shaving plane, at least in part, by at least one of the plurality of resilient members, and wherein at least one of the plurality of blades is biased toward the shaving plane with a first force that is greater than a second force biasing another of the plurality of blades toward the shaving plane.