Cutting Chain Recess Geometry for Higher Sag Without Wear

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Solution Overview

Problem

Cutting chains for metallic or mineral materials face issues with mechanical load and reduced service life due to sagging, which causes contact between cutting elements and extensions, leading to premature wear.

Innovation Solution

Incorporating recesses on the cutting chain to increase the maximum sag without contact between cutting elements and extensions, allowing for a longer cutting element length and reduced mechanical load, thereby enhancing the chain's operational smoothness and longevity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the cutting chain is designed with minimal distance between cutting element and extension, then the cutting chain runs smoothly, but the maximum sag is reduced increasing contact risk between extension and cutting element

Engineering Contradiction:
Improvesmooth operationVSAvoidservice life
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The recess is provided only at specific locations on the drive link (at the extension) rather than throughout the entire structure, allowing the extension to dip into the recess when sag occurs, while maintaining structural integrity elsewhere. This localized modification enables increased maximum sag without compromising overall chain strength or smooth operation during normal conditions.

Inventive Principle:
Principle #3Local quality

2Productivity

If the cutting element length is increased, then material removal efficiency is improved, but the distance to leading and trailing humps must be maintained limiting the cutting element length

Engineering Contradiction:
Improvematerial removal efficiencyVSAvoidcutting element length
Core Design Contradiction:
ProductivityVSLength of moving object

Solution Approach 1:

The recess creates additional vertical space at the extension location, allowing the cutting element to extend further in the cutting direction without increasing the horizontal distance to leading and trailing humps. This dimensional approach enables longer cutting elements for improved productivity while maintaining the required clearance geometry.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If the maximum sag is increased to reduce contact risk, then the cutting element can be longer, but the cutting chain may not run smoothly

Engineering Contradiction:
Improveservice lifeVSAvoidsmooth operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The recess acts as a pre-prepared cushioning space that absorbs the sagging motion before it can cause harmful contact between the extension and cutting element. By providing this recess in advance, the design allows for increased maximum sag without compromising smooth operation, as the recess accommodates the sagging movement during normal operation.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP3865266B1Cutting chain for cutting mineral or metallic materials
Publication Date: 2023.08.16 ANDREAS STIHL AG & CO KG
  • EP3865266B1 patent drawingFigure 1~4
  • EP3865266B1 patent drawingFigure 5~10
  • EP3865266B1 patent drawingFigure 11~19

AI summary

A cutting chain for cutting mineral or metallic materials has central drive links (15) and lateral, paired side links (19) which are pivotally connected to each other about pivot axes (20). The cutting chain (1) has at least two cutting links (16) arranged one behind the other in the direction of travel (13), each cutting link being formed by two side links (19) of a pair and a cutting element (17) for abrasive material removal, which connects the side links (19) of the pair. The drive link (15) has a projection (30) that extends between the two cutting elements (17) arranged one behind the other in the direction of travel (13).The cutting chain (10) has at least one recess (29, 31) which is arranged and designed such that the maximum sag (a) of the cutting chain (10), at which the cutting element (17) and the extension (30) come into contact, is increased compared to the same cutting chain (10) without recess (29, 31).