Chain Saw Engine Housing Fixing for Vibration Control
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Solution Overview
Problem
Conventional chain saws face challenges in achieving stable operation while minimizing size and weight, particularly due to the inferior stiffness and strength of plastic housings, which affect vibration characteristics and handling.
Innovation Solution
The chain saw employs a fixing member, such as bolts or screws, to securely attach the engine to the housing, with a transverse bolt parallel to the crankshaft reducing vibrations by anchoring at critical points affected by the saw chain's reaction forces, and using polymer resin for lightweight yet strengthened housing components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the housing is made of plastics to reduce weight, then the weight of the chain saw is reduced, but the stiffness and strength of the housing deteriorate
Solution Approach 1:
The patent uses a plastic housing combined with metal reinforcement ribs to create a composite structure. The plastic provides lightweight properties while the metal ribs provide the necessary stiffness and strength, resolving the contradiction between weight reduction and structural integrity.
Solution Approach 2:
The housing is segmented into different functional regions with varying thickness and reinforcement. Critical areas receiving reaction forces from the saw chain are reinforced with additional ribs or thicker material, while non-critical areas remain thin to minimize weight.
2Reliability
If the engine is fixed to the housing with multiple fixing members, then the vibration characteristics are improved, but the device complexity increases
Solution Approach 1:
The patent applies fixing members at specific critical locations on the housing where reaction forces from the saw chain are transmitted. Rather than uniformly distributing fixings, the design targets specific areas to maximize vibration reduction while minimizing the number of fixing members required.
3Weight of moving object
If the chain saw is miniaturized for easy handling, then the size and weight are reduced, but the structural strength deteriorates
Solution Approach 1:
The patent compensates for reduced material volume in miniaturized components by optimizing the three-dimensional distribution of material. The housing features strategically placed reinforcement ribs that extend in multiple directions to provide structural strength without increasing overall size or weight proportionally.
Data Source
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AI summary
According to an aspect of the present invention, there is provided a chain saw (1) including: an engine (50) having: a crankcase (52, 53); a cylinder (55) attached to the crankcase (52, 53); and a piston (62) configured to reciprocate in the cylinder (55); a housing (2) configured to accommodate the engine (50); and a guide bar (11), around which a saw chain (10) is to be wound so as to be rotated by the engine (50), the guide bar (11) being attached to the housing (2), wherein the engine (50) has two surfaces substantially parallel to an axis direction of a crankshaft (51), the two surfaces being covered with and fixed to the housing (2), and wherein the engine (50) is fixed to the housing (2) with a fixing member (41) at a side where the guide bar (11) is attached to the housing (2).