Stationary Blade Sheet Metal Folded Edges

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Solution Overview

Problem

Existing manufacturing methods for double-walled stationary blades in hair cutting appliances are costly due to the need for expensive tooling and complex post-processing procedures, such as insert molding and overmolding, which increase production costs and complexity.

Innovation Solution

A method of manufacturing a stationary blade using sheet metal with multiple folded edges at the frontal ends, allowing for a thinner top wall and a thicker bottom wall, which enhances strength and shaving performance while maintaining cost-efficiency by eliminating the need for complex tooling and hybrid manufacturing approaches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If insert molding and overmolding methods are used to manufacture double-walled stationary blades, then the structural integrity and design flexibility are improved, but the manufacturing cost and process complexity increase significantly

Engineering Contradiction:

Improvestructural integrityVSAvoidmanufacturing cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent changes the manufacturing parameters from hybrid insert molding/overmolding to a single-shot injection molding process. This parameter change maintains the ability to produce double-walled structures with varying wall thicknesses while eliminating the need for expensive multi-step tooling and assembly operations, thereby reducing manufacturing cost while preserving structural integrity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a single mold that can produce the complete double-walled stationary blade structure in one operation. The mold is designed to form both walls and the intermediate material in a single shot, making the manufacturing process universal and eliminating the need for separate insert molding and overmolding steps, thus reducing both cost and complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Strength

Engineering Contradiction:

Improvestructural integrityVSAvoidmanufacturing process complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent merges the insert molding and overmolding processes into a single-shot injection molding operation. The mold is designed with cavities that form both walls simultaneously, and the intermediate material is injected in the same cycle, combining multiple complex steps into one simpler process that reduces manufacturing process complexity while maintaining structural integrity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent incorporates the intermediate material and bonding surfaces into the initial mold design and single injection process. By preliminarily forming all structural elements including the bonding interfaces in one shot, the need for subsequent assembly and post-processing operations is eliminated, thereby reducing manufacturing process complexity

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If the top wall is made thinner to improve shaving performance, then the cutting precision is improved, but the overall strength of the stationary blade decreases

Engineering Contradiction:

Improvecutting precisionVSAvoidoverall strength

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The patent applies local quality by creating a double-walled structure where the top wall can be made thinner for improved cutting precision and contact with the movable blade, while the bottom wall maintains sufficient thickness for structural strength. The intermediate material provides additional local reinforcement, allowing differential wall thicknesses that optimize both cutting precision and overall strength

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite construction with the intermediate material bonding the top and bottom walls. This composite structure allows the top wall to be thin for cutting precision while the bottom wall and intermediate material provide the necessary overall strength, creating a composite blade that combines the benefits of different wall thicknesses in a single integrated component

Inventive Principle:

Principle #40Composite materials

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 approach enables the production of cost-efficient stationary blades with improved strength and shaving performance, achieving accurate guide slot clearance for the movable blade, resulting in enhanced cutting performance and reduced manufacturing complexity.

Implementation Method 1

at the frontal ends, two or more sheet metal folded edges are present

Methodology Applied

Scientific EffectFolding: Folding

Data Source

PatentUS11370134B2Stationary blade, blade set, and manufacturing method

Publication Date: 2022.06.28 KONINKLIJKE PHILIPS NV

AI summary

A stationary blade for a blade set of a hair cutting appliance includes a top wall, a bottom wall, and a guide slot formed between the top and bottom walls to accommodate a movable blade. The stationary blade further includes a plurality of stationary blade teeth each having a frontal end. The top and bottom walls are mutually joined at the frontal ends, where the top and bottom walls are, at least at the frontal ends, made from sheet metal material. Further, at the frontal ends, two or more sheet metal folded edges are present.