Saw Chain Cutting Tooth Brazing Geometry

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Solution Overview

Problem

Existing cutting teeth for saw chains have limited durability and cutting performance due to a small, restricted connection between the hard metal cutting element and the base body, leading to reduced service life under high loads.

Innovation Solution

The cutting tooth design features a large-area connection between the hard metal cutting element and the base body, with a strategically positioned corner point in the chip recess and a countersink that supports the cutting element, ensuring a strong bond and optimal positioning for high load resistance and extended service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the cutting element is made relatively small compared to the base body, then the brazing surfaces are limited and the connection area is reduced, but the cutting tooth can still be manufactured with simpler geometry

Engineering Contradiction:
Improveconnection strength between cutting element and base bodyVSAvoidgeometry complexity of cutting tooth
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The chip recess is extended in the direction of travel to create an elongated geometry that increases the brazing surface area without significantly increasing the overall size of the cutting element. This dimensional extension along the travel direction provides larger connection area while maintaining compact transverse dimensions

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

Solution Approach 2:

The cutting element features an angled lower longitudinal edge (chamfer) at 0.5° to 2° that creates optimized local contact conditions with the base body. This local geometric modification enhances the brazing connection quality at the critical interface between cutting element and base body

Inventive Principle:
Principle #3Local quality

2Reliability

If the cutting element is made small, then the brazing surface area is limited, but the manufacturing process becomes simpler

Engineering Contradiction:
Improveservice life of cutting toothVSAvoidmanufacturing complexity of cutting tooth
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The chip recess is extended along the direction of travel to provide a larger brazing surface area, which improves the reliability and service life of the cutting tooth without requiring a larger cutting element or more complex manufacturing processes

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

Solution Approach 2:

The geometry parameters of the chip recess and cutting element are optimized with specific angle ranges (0.5° to 2° for the chamfer, 35° to 40° for the distance line) to achieve reliable connections while maintaining ease of manufacture through standardized angular specifications

Inventive Principle:
Principle #35Parameter changes

3Force

If the corner point is positioned forward in the chip recess, then the cutting tooth can withstand heavy loads better, but the chip recess geometry becomes more constrained

Engineering Contradiction:
Improveload resistance of cutting toothVSAvoidchip recess geometry
Core Design Contradiction:
ForceVSShape

Solution Approach 1:

The position of the corner point is defined by specific geometric parameters (distance A = 0.5 to 0.8 times distance B, optimally 0.65 times) that optimize load resistance while maintaining feasible chip recess geometry. The angular parameters (35° to 40°) further constrain the geometry to achieve optimal force distribution

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The corner point position creates a localized stress distribution pattern that concentrates load-bearing capacity at the critical interface between chip recess and cutting element, allowing the cutting tooth to withstand heavy loads without requiring overall geometric changes

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

This design enhances cutting performance and extends the service life of the cutting tooth by providing a durable connection and effective load distribution, resulting in improved operational reliability and longevity.

Implementation Method 1

one side section of the cutting element being brazed to the side surface of the base body

Methodology Applied
Scientific EffectBrazing: Brazing

Data Source

PatentEP2883669B1Cutting tooth for a saw chain
Publication Date: 2016.06.01 ANDREAS STIHL AG & CO KG
  • EP2883669B1 patent drawingFigure 1
  • EP2883669B1 patent drawingFigure 2~3
  • EP2883669B1 patent drawingFigure 4

AI summary

The invention relates to a cutting tooth (1) for a saw chain, comprising a base body (2) with a cutting element (3) made of carbide attached to the base body (2). The carbide cutting element (3) has a top cutting edge (16) and a side section (7) with a side cutting edge (17). A chip recess (5) for chip evacuation is provided in the base body (2), wherein the cutting element (3) projects into the chip recess (5) and, in a side view of the base body (2), a front contour (14) of the side section (7) and the inner contour (15) of the chip recess (5) form a corner point (8). According to the invention, the corner point (8) is located at a first distance (A) to a vertical edge (9) of the depth limiter (4) that defines the chip recess (5), which is smaller than a second distance (B) between a median plane (V) dividing the rivet spacing (N) and the vertical edge (9) of the depth limiter (4).The vertical edge (9) of the depth limiter (4) lies in the direction of travel (LR) in front of the central axis (M1) of the front rivet opening (11).