Ergonomic Kitchen Knife Handle Geometry for Grip Stability

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Solution Overview

Problem

Existing kitchen knives often fail to balance design criteria such as comfort, safety, muscle fatigue prevention, cutting precision, and grip optimization, leading to suboptimal user experience and potential premature blade wear.

Innovation Solution

A knife design featuring a handle with specific geometric parameters, including a longitudinal flare angle between 3° and 8°, a handle height to deflection ratio of 13% to 20%, and gripping edges positioned to fit the user's interphalangeal line, ensuring a secure and comfortable grip without excessive pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the handle is made with traditional designs favoring one aspect, then that aspect is improved, but the balance between comfort, safety, and control deteriorates

Engineering Contradiction:
Improvegrip comfortVSAvoidsafety and control
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies parameter changes by defining specific geometric parameters for the handle: longitudinal flare angle between 3° and 8°, and the ratio between lower deflection and handle height between 13% and 20%. These parameter specifications transform the handle design from subjective ergonomic considerations to objective, measurable geometric constraints that simultaneously optimize both comfort and control.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The handle design incorporates asymmetry through the longitudinal flare that extends from the connecting portion, creating an uneven distribution of handle height along the longitudinal direction. This asymmetric geometry naturally adapts to the hand's contour while providing specific contact points that enhance both comfort and precise control.

Inventive Principle:
Principle #4Asymmetry

2Measurement precision

If excessive pressure is applied on the handle, then cutting precision may be improved, but muscle fatigue increases

Engineering Contradiction:
Improvecutting precisionVSAvoidmuscle fatigue
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the distribution of handle height along the longitudinal direction using specific geometric parameters. The longitudinal flare angle of 3°-8° and the deflection-to-height ratio of 13%-20% create an ergonomic profile that distributes pressure evenly across the hand, reducing the need for excessive gripping force while maintaining cutting precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The handle geometry creates equipotential pressure distribution by carefully designing the longitudinal flare and deflection characteristics. This ensures that the hand contacts the handle at multiple points with balanced pressure, eliminating pressure concentrated points that would require additional muscular effort to maintain grip.

Inventive Principle:
Principle #12Equipotentiality

3Ease of manufacture

If the handle shape does not adapt to hand shape, then manufacturing is simpler, but grip comfort and safety deteriorate

Engineering Contradiction:
Improvehandle fabricationVSAvoidgrip comfort and safety
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent transforms complex ergonomic shaping into manufacturable geometry by defining specific parameters: longitudinal flare angle (3°-8°) and lower deflection to handle height ratio (13%-20%). These parameterized specifications allow the adaptive handle shape to be produced using standard manufacturing processes while maintaining the ergonomic benefits of hand-adapting geometry.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4633884B1Kitchen knife
Publication Date: 2026.04.15 SEB SA
  • EP4633884B1 patent drawingFigure 1~2
  • EP4633884B1 patent drawingFigure 3~4
  • EP4633884B1 patent drawingFigure 5~6

AI summary

The invention relates to a knife comprising a blade (1) and a handle (2) having a main gripping portion (200), wherein the main gripping portion (200) of the handle (2) has a shape that widens longitudinally in the longitudinal plane and is defined by a longitudinal widening angle α formed between a lower edge (222) and an upper edge (221), the longitudinal widening angle α having a set value between 3° and 8°, and wherein the distance in the longitudinal plane between the lower edge (222) and the upper edge (221) at a given position in the longitudinal direction (L) defines a handle height (H), and the distance in the longitudinal plane between the lower edge (222) and the projection of the gripping ridge (2233) in the longitudinal plane at a given position in the longitudinal direction (L) defines a lower sagitta (Fi), the ratio between the lower sagitta (Fi) and the handle height (H) being substantially constant at any point on the main gripping portion (200) of the handle (2) in the longitudinal direction (L) and having a set value of between 13% and 20%.