Composite Bushing Joining Metal Cutting Lines

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Solution Overview

Problem

Existing systems for joining metal cutting lines in cutting machines for stone, wood, and metal products have a low failure limit, restricting increased shear stresses and cutting speed, which compromises operator safety due to the risk of diamond wire breakage.

Innovation Solution

A bushing system with a harder external part and a softer internal part, combined with a friction element like silicon carbide or tungsten carbide powder/grains, is used to join the ends of the cutting line, increasing the breaking strength and safety by enhancing friction and load capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a bushing is used to join the ends of the cutting line by pressing and squashing it, then the joining process is simple and effective, but the failure limit of the joined line is low, which limits the increase of shear stresses and cutting speed

Engineering Contradiction:
Improvejoining process simplicityVSAvoidbreaking strength of joined line
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The bushing is designed with non-uniform hardness distribution: the external part has higher hardness (180-250 HB) to resist deformation and maintain structural integrity, while the internal part has lower hardness (120-160 HB) to deform and conform to the cutting line ends, creating a tight interference fit that significantly increases breaking strength

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The bushing combines two different metal materials with distinct hardness properties - the external part uses harder steel for strength and wear resistance, while the internal part uses softer steel for adaptive deformation and friction-based locking, creating a composite structure that simultaneously achieves simple manufacturing and high breaking strength

Inventive Principle:
Principle #40Composite materials

2Productivity

If the cutting speed is increased to improve productivity, then the cutting efficiency increases, but the risk of diamond wire breakage increases, compromising operator safety

Engineering Contradiction:
Improvecutting speedVSAvoidsafety against wire breakage
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The bushing utilizes interference fit and friction forces through its cylindrical geometry to create a gradual stress distribution around the cutting line ends, avoiding stress concentration points that would lead to sudden wire breakage, thereby enabling higher cutting speeds with improved safety

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

By changing the hardness parameter of the bushing materials and their distribution, the system increases the failure limit of the joined line, allowing operation at higher shear stresses and cutting speeds without increasing the risk of wire breakage

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

The system significantly increases the breaking strength of the cutting line, allowing for higher cutting speeds and improved productivity while ensuring operator safety by distributing loads effectively and creating additional friction surfaces.

Implementation Method 1

at least one friction element, made of a material of greater hardness than both the hardness of the bushing part with which it is in contact and the hardness of the line, is interposed between the line and the inner surface of the bushing hole

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

pressing the bushing at opposite sides on its outer surface, thus deforming it so that the inner surface of the bushing hole is pressed against the two ends of the cutting line

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP3338932B1Sytem for joining two ends of a metal cutting line for cutting machines for stone, wood, and metal products and the like
Publication Date: 2023.08.30 DAZZINI SRL
  • EP3338932B1 patent drawingFigure 1~2
  • EP3338932B1 patent drawingFigure 3~4
  • EP3338932B1 patent drawingFigure 5~6

AI summary

A system for joining two ends (11A, 11B) of a metal cutting line for cutting machines for stone, wood, and metal products and the like, comprising a metal bushing (12) provided with a through hole (13), inside which the ends of the line can be inserted and which is suitable to deform inwards to block said ends, characterized by comprising at least one friction element (16) interposed between the hole surface of said bushing and said line.