Slate Cutter Levers With Optimized Handle Angle

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Solution Overview

Problem

Existing crushing devices, such as slate shears, are not easily maneuverable, particularly when used at chest height with the support surface oriented horizontally, as they require a specific angle between the handle and support lines that is not efficiently accommodated by existing designs.

Innovation Solution

The crushing device is designed with an angle between the support line and the handle line limited to less than 20°, allowing operation with the support surface oriented both horizontally upwards and downwards, featuring a Z-shaped lever configuration with a compression spring mechanism and a U-shaped support surface for improved ergonomics and visibility of the cutting edge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the angle between the support line and handle line is increased to allow operation at chest height, then the tool becomes more maneuverable, but the structural stability and cutting precision deteriorate

Engineering Contradiction:
Improvemaneuverability at chest heightVSAvoidcutting precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent optimizes the angle between the support line and handle line to be less than 20 degrees, creating an ergonomic configuration that allows comfortable operation at chest height while preserving cutting precision. This parameter optimization resolves the contradiction by finding the optimal angular relationship that satisfies both maneuverability and precision requirements.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If the support surface is made visible from both sides, then the adaptability for different operating orientations is improved, but the device complexity increases

Engineering Contradiction:
Improveoperation with upward or downward support surfaceVSAvoidstructural complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The support surface is designed as a flat piece with a rear surface parallel to the support surface, creating a U-shaped structure that is visible from both sides. This allows the tool to be operated with the support surface oriented either upward or downward, providing universal adaptability for different working conditions without requiring multiple separate components.

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

Solution Approach 2:

The flat piece forming the support surface has an asymmetric U-shaped cross-section with the open side facing the cutting edge. This asymmetric design enables the support surface to be visible and functional from both sides while maintaining structural integrity, allowing operation in both upward and downward orientations.

Inventive Principle:
Principle #4Asymmetry

3Ease of operation

If the handle arms are positioned parallel to the support surface, then the ergonomic comfort is improved, but the structural compactness deteriorates

Engineering Contradiction:
Improveergonomic comfortVSAvoidstructural compactness
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The handle arm is positioned at an optimized angle relative to the support surface, lying approximately in a plane parallel to the support surface at a sufficient distance. This parameter optimization provides ergonomic comfort for hand placement while maintaining acceptable structural compactness.

Inventive Principle:
Principle #35Parameter changes

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 enhances manageability and usability by allowing comfortable operation with either upward or downward pointing cutting edges, maintaining consistent user arm angle and providing clear visibility of the cutting direction, thus improving operational efficiency and user experience.

Implementation Method 1

featuring a Z-shaped lever configuration with a compression spring mechanism

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP2656990B1Slate cutters
Publication Date: 2015.09.23 P F FREUND & CIE
  • EP2656990B1 patent drawingFigure 1~3
  • EP2656990B1 patent drawingFigure 4~6
  • EP2656990B1 patent drawingFigure 7

AI summary

The invention relates to a breaking device for plate-shaped workpieces, such as slate slabs, cement slabs, or the like, with two levers (1, 2), each having a handle arm (3, 4), a breaking arm (5, 6), and an intermediate bearing section (7, 8), wherein the two levers (1, 2) are pivotably connected to each other about a pivot axis (9) such that, when the device is closed from an open to a closed position by pivoting the two handle arms (3, 4) towards each other, a cutting edge (10) formed by one breaking arm (5) moves against a support surface (11) formed by the other breaking arm (6), wherein a grip zone (3') of the lever (2) forming the support surface (11) defines a grip line (B) extending in the direction of extension of the handle arm (3) and lying in a cross-sectional plane through the pivot axis (9) of the device, and the support surface (11) defines a support line lying in the cross-sectional plane of the device. (A) defined.To improve the handling of the generic tool, the invention proposes that the angle between the support line (A) and the handle line (B) be less than 30°.