Chainsaw Guide Bar Assembly for Precise Guide Groove Formation

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Solution Overview

Problem

Existing laminated guide bars for chainsaws face challenges in maintaining dimensional accuracy and reducing distortions during manufacturing processes, particularly due to heat treatments, which affect the precision and performance of the guide groove.

Innovation Solution

A method involving a core plate with detachable elements that act as spacers, integrated during assembly and heat treatment, to maintain plate alignment and prevent distortions, followed by removal to form a guide groove.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If heat treatment is applied to join metal plates, then joining strength is improved, but dimensional accuracy and plate alignment deteriorate due to distortions

Engineering Contradiction:
Improvejoining strengthVSAvoiddimensional accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

A detachable element is introduced as an intermediary component between the core plate and side plates. This element remains attached to the core plate during the heat treatment joining process, acting as a mediator that prevents direct thermal contact and subsequent distortions between the metal plates, thereby maintaining dimensional accuracy while still allowing strong joining through the attachment mechanism

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The detachable element is attached to the core plate before the heat treatment process begins. This preliminary action ensures that the element is in position to prevent distortions during joining, and the element is removed only after the joining is complete, thus preserving dimensional accuracy throughout the critical manufacturing stages

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If detachable elements are used to maintain alignment, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improveplate alignmentVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The detachable element is designed to be removed after serving its alignment function during heat treatment. By extracting this element after the critical joining phase, the guide bar achieves simplified final structure without the permanent presence of additional components, thus reducing device complexity while maintaining manufacturing precision during the critical process

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If multiple plates are joined together, then structural strength is improved, but maintaining uniform guide groove dimensions becomes more difficult

Engineering Contradiction:
Improvestructural strengthVSAvoidguide groove uniformity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The detachable element serves as a mediator that maintains consistent spacing and alignment between the core plate and side plates during the heat treatment process. This ensures that the guide groove dimensions remain uniform throughout the joining process, preventing variations that would otherwise occur due to thermal distortions in multi-plate construction

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Ensures precise and uniform guide grooves, reducing stress on the saw chain and enhancing the durability and performance of the guide bar by maintaining plate alignment and minimizing distortions.

Implementation Method 1

The detachable element can act as a detachable spacer which supports the inward-facing sidewalls of the side plates and thereby maintains a well-defined distance between side plates during the joining process

Methodology Applied
Scientific EffectMechanical support:

Implementation Method 2

If the plates (side plates and core plate) are made of metal, such as for example steel, distortions between the plates may occur if heat is provided to the plates during the joining process

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

The three plates may be attached to each other by welding, normally spot welding or pressure welding, brazing, adhesives, mechanical fasteners, such as rivets or bolts

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 4

The three plates may be attached to each other by welding, normally spot welding or pressure welding

Methodology Applied
Scientific EffectPressure welding:

Implementation Method 5

By providing the core plate with at least one detachable element that remains attached to the core plate during these heating processes, distortions between the plates may be further reduced

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentEP4034355B1Methods for production of a guide bar for a chainsaw, and a guide bar for a chainsaw
Publication Date: 2025.11.05 HUSQVARNA AB
  • EP4034355B1 patent drawingFigure 1
  • EP4034355B1 patent drawingFigure 2~4
  • EP4034355B1 patent drawingFigure 3

AI summary

The present disclosure relates to a method (100) for production of a chainsaw guide bar (5). The method comprises the steps of providing (120) an elongated core plate (5) extending along a plane, and, in said plane has a length (Lc) in the longitudinal direction (D), and a width (Wc) perpendicular to the longitudinal direction (D), comprising a pair of opposite long side edges (33) and at least one detachable element (31) that extends along at least one of the long side edges of the core plate. Arranging (140) a side plate (23a, 23b) on each side of the core plate (25), thereby forming a sandwiched structure and joining (160) of the plates (23a, 23b, 25) for formation of an elongated guide bar (5), wherein the at least one detachable element (31) remains attached to the core plate (25). The disclosure also relates to a guide bar (5) for a chainsaw (1). The guide bar (5) comprises a laminated structure of at least three layers comprising a first side plate (23a), a second side plate (23b), and a core plate (25) disposed between said first side plate (23a) and said second side plate (23b),wherein the core plate (25) is provided with at least one detachable element (31). The disclosure also relates to an alternative method (200) of production of a chainsaw guide bar (5).