Multi-Material Sharpening Rod with Segmented Abrasive Surfaces

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Solution Overview

Problem

Existing sharpening rods are costly to produce and lack the ability to efficiently switch between coarse and fine sharpening surfaces, often requiring multiple rods and inadequate bonding strength for effective tool sharpening.

Innovation Solution

A sharpening rod composed of three partial rods, with one central rod made from a second material and two outer rods made from a first material, connected via glaze for optimal material utilization and wear resistance, allowing for easy switching between coarse and fine sharpening surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a sharpening rod is made from a single material with uniform grain size, then the manufacturing process is simple, but the ability to provide both coarse and fine sharpening surfaces is limited

Engineering Contradiction:
Improveability to provide both coarse and fine sharpening surfacesVSAvoidstructure of sharpening rod
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The sharpening rod is divided into multiple segments with different grain sizes (e.g., coarse grit on one end, fine grit on the other end). This segmentation allows each segment to perform a specific sharpening function, enabling the rod to provide both coarse and fine sharpening surfaces while maintaining a unified structure that is easier to manufacture than fully customized multi-rod systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sharpening rod is designed to perform multiple functions by incorporating different grain sizes in different regions. A single rod can thus serve both as a coarse sharpening tool and a fine honing tool, eliminating the need for users to maintain separate rods for different sharpening stages and simplifying the overall system while increasing versatility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If adhesive bonding is used to join blocks of different abrasive material, then different roughnesses can be formed on one rod, but the bonding strength is relatively low and only suitable for low-load applications

Engineering Contradiction:
Improveformation of different roughnesses on one rodVSAvoidbonding strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent replaces chemical adhesive bonding with mechanical bonding methods such as friction welding, ultrasonic welding, or interference fitting. These mechanical bonding techniques provide significantly higher bond strength compared to adhesives, enabling the rod to withstand high loads and heavy-duty sharpening applications while still allowing the integration of different abrasive materials with different roughnesses.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If a cross-shaped cross section with grooves is used to form grinding surfaces, then different grinding materials can be placed in grooves, but the production cost is relatively expensive

Engineering Contradiction:
Improveplacement of different grinding materialsVSAvoidproduction cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

Instead of using a complex cross-shaped cross section with grooves for all grinding surfaces, the patent applies local quality by using different cross-sectional shapes only where needed. For example, the rod may have a circular cross section for the handle portion and only transition to a cross-shaped or grooved section at the working end where different grinding materials are required. This reduces overall manufacturing complexity and cost while still providing the versatility of multiple grinding materials.

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

The solution reduces manufacturing costs and enhances durability by forming high-strength connections between ceramic partial rods, enabling effective and efficient sharpening of tools with improved wear resistance and precise fineness adjustment.

Implementation Method 1

The partial rods are connected to one another by means of glaze

Methodology Applied
Scientific EffectGlaze bonding: Sintering

Implementation Method 2

Bonding is done by warm or hot bonding

Methodology Applied
Scientific EffectThermal bonding: Hot Isostatic Pressing

Implementation Method 3

The material of the sharpening rods has a corresponding grain size depending on the requirement. Sharpening rods are made with a coarser grain for a coarse grind and sharpening rods with a fine grain for a fine grind

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP2147748B1Knife sharpener and method for its production
Publication Date: 2011.05.04 HIGH TECH CERAMIC E K
  • EP2147748B1 patent drawingFigure 1
  • EP2147748B1 patent drawingFigure 2
  • EP2147748B1 patent drawingFigure 3

AI summary

The rod (1) has a peripheral surface with two pairs (2, 3) of sharpening surfaces (2a, 2b, 3a, 3b). The rod is formed of a material with a predetermined grain size. The sharpening surfaces of each pair are located opposite to each other transverse to a longitudinal direction of the rod. The pairs of sharpening surfaces are arranged offset with respect to each other in peripheral direction of the rod. The sharpening surfaces-pairs are formed from two respective materials with respective grain sizes. Four partial rods are formed from a same material e.g. aluminum oxide-ceramics. An independent claim is also included for a method for manufacturing a sharpening rod.