Top-Handle Chainsaw Handguard Pivot for View Clearance

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Solution Overview

Problem

Top-handle chain saws face challenges in usability during difficult working conditions such as tree climbing or working in cramped spaces, where the handguard obstructs the user's view and can be hindered by surrounding branches.

Innovation Solution

The handguard of the top-handle chain saw is designed to pivot further rearward, reducing obstruction of the user's view and allowing more clearance in cramped spaces by being connected below and in front of the front tower, enabling it to be drawn back further and thus reducing interference from branches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the handguard is positioned closer to the guide bar for better chain brake activation, then the chain brake functionality is improved, but the user's view of the guide bar is obstructed and the saw is hindered in cramped spaces

Engineering Contradiction:
Improvechain brake activationVSAvoiduser view and maneuverability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The handguard is made pivotable relative to the housing, allowing it to move between a forward position for brake activation and a rearward position for unobstructed view and maneuverability. This dynamic repositioning resolves the contradiction between needing the handguard close to the guide bar for brake function and needing it away for operational ease.

Inventive Principle:
Principle #15Dynamics

2Volume of moving object

If the handguard connection point is located at the front tower for compact design, then the overall size is reduced, but the handguard cannot be drawn back far enough to reduce obstruction

Engineering Contradiction:
Improvesaw compactnessVSAvoidhandguard retraction distance
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The handguard connection is positioned at the front part of the front tower, utilizing the vertical dimension of the tower structure. This allows the handguard to pivot in an arc that extends further rearward than a horizontal connection would permit, achieving both compact forward position and extended rearward retraction.

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

Data Source

PatentEP3546162B1chainsaw
Publication Date: 2023.04.12 HUSQVARNA AB
  • EP3546162B1 patent drawingFigure 1~2
  • EP3546162B1 patent drawingFigure 3~5

AI summary

The present disclosure relates to a top-handle chain saw 1 comprising a housing 3 and a guide bar 5, projecting from the housing in a front direction and carrying a saw chain 7. A top handle 9 on the housing, extends from a rear tower on the housing to a front tower on the housing, and a side handle 15 extends laterally from the top handle. A handguard 17 has a proximal end pivotably connected to the housing 3 and a distal end extending into a space in between the side handle 15 and the guide bar 5. The handguard is moveable between a forward position where a saw chain brake is activated and a backward position where the saw chain brake is released, and is devised such that its distal end in said backward position is located further to the rear, away from the guide bar 5, than the front tower to which the top handle 9 is connected.