The chain saw engines are single-cylinder, the vibration of the engines themselves are significant. To minimize the vibratory acceleration transmitted to the handles from this sources, an anti-vibration device is required to damp vibration suitably. This type of anti-vibration device, however, requires a rather soft spring constant and anti-vibration rubber bushings with high deformation, that is the size and bulkiness of which not only make forestry work difficult, but also dangerous.
To resolve these problems it is essential to reduce the vibration acceleration as far as possible by optimizing engine balance. The two stroke cycle horizontally-opposed 2-cylin-der simultaneous-ignition engine provides the best balance for chain saw applications, and research and development was advanced on this basis.
The results showed a reduction in vibration acceleration level at the engine itself to about 10% of conventional 1-cylinder chain saw engine, and reduction in the handles to about 20%.
The objectives of the development project for a low-vibration chainsaw have been almost completely reached, and user evaluations support the excellent test results concerning noise reduction.