Knife Sharpener Guide Structure for Hollow Ground Blades

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Solution Overview

Problem

The existing knife sharpeners face instability and ambiguity in positioning sport, pocket, and tactical knife blades with hollow ground concave blades, leading to compromised angular control due to excessive friction and tilting, especially with thicker blades.

Innovation Solution

A unique combination of a non-planar knife angle guide and a spring design that mimics the blade profiles, with convex portions to match the concave shape of the blades, reducing friction and ensuring precise alignment, and a modular spring system for versatility across different knife types.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a planar angle guide is used to control sharpening angle, then the sharpening angle can be controlled, but the positioning becomes unstable and ambiguous for thick knives with hollow ground concave blades

Engineering Contradiction:
Improvesharpening angle controlVSAvoidblade positioning stability
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent applies curvature by replacing the planar guide surface with a non-planar guide surface that has a convex portion matching the concave shape of hollow ground knife blades. This curved surface provides stable contact and precise positioning for thick knives with hollow ground edges, resolving the instability issue while maintaining angle control precision.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Ease of operation

If a spring is used to hold the blade against the guide, then the blade can be held in place, but friction increases as the blade is pulled through the sharpening slot

Engineering Contradiction:
Improveblade holding capabilityVSAvoidfriction during sharpening
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent changes the geometric parameters of the spring guide surface by providing a convex portion that matches the concave blade profile. This geometric adaptation reduces contact friction between the spring and blade during the sharpening process, making it easier to pull thick knives through the sharpening slot while still maintaining secure blade holding.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If the guide surface is made non-planar to match blade profiles, then positioning precision improves, but the device complexity increases

Engineering Contradiction:
Improveblade alignment precisionVSAvoidguide structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by making only the specific contact portions of the guide surface non-planar (convex portions) to match the hollow ground blade profiles, while the rest of the guide structure can remain simpler. This localized adaptation provides precise positioning for thick knives without requiring complete redesign of the entire guide system, thus limiting the increase in device complexity.

Inventive Principle:
Principle #3Local quality

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 achieves stable and precise sharpening of a variety of knives, including thicker sport and tactical knives, by reducing friction and maintaining alignment, while also accommodating thinner blades and narrower knives, enhancing the overall sharpening precision and effectiveness.

Implementation Method 1

a spring having a guide surface forming a slot to guide a knife blade against a sharpening member

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3245026B1Sharpener for thick knives
Publication Date: 2024.03.27 EDGECRAFT CORP
  • EP3245026B1 patent drawingFigure 1
  • EP3245026B1 patent drawingFigure 2~3
  • EP3245026B1 patent drawingFigure 2A~3A

AI summary

A knife sharpener includes guide structure for accommodating thick blades of a knife. The guide structure includes a fixed guide surface having a. convex portion to match a concave shape of the blade and a spring guide surface preferably has a convex portion to press against a hollow ground portion of the blade.