Battery Pack Layout for Balanced Top-Handle Chainsaws
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Solution Overview
Problem
Existing battery-operated chainsaws with large, high-voltage battery packs are expensive and limited in use, and using multiple small battery packs for power can lead to operability issues due to improper weight distribution, causing the chainsaw to incline and reduce user comfort.
Innovation Solution
A chainsaw design that utilizes multiple rechargeable battery packs detachably mounted on the body housing, strategically positioned to maintain the center of gravity within specific limits, ensuring balanced operation and reducing fatigue, with the packs adaptable for use in other electric power tools, and featuring a protector member to prevent damage when placed horizontally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a large size high voltage battery pack is used to drive the high power motor, then sufficient power supply is achieved, but the battery pack becomes expensive and limited only for use in chainsaws
Solution Approach 1:
The battery power system is segmented into multiple small size battery packs instead of using a single large high voltage battery pack. These smaller battery packs can be used individually or combined in series to achieve the required voltage and power levels, making them versatile for different power tool applications while maintaining sufficient power supply capability for the chainsaw motor.
2Adaptability or versatility
If multiple small size battery packs are used as power supply source, then cost and versatility are improved, but the chainsaw becomes inclined in left-and-right direction deteriorating operability
Solution Approach 1:
The battery packs are positioned at specific locations on the body housing with precise lateral spacing control. The patent specifies that the distance between the lateral centers of the battery packs should be 0.02 to 0.2 times the lateral width of the grip portion, creating an optimal weight distribution that maintains chainsaw balance and operability while using multiple small battery packs.
3Ease of manufacture
If battery packs are not mounted on an appropriate place of the body housing, then installation flexibility is improved, but the chainsaw becomes inclined in left-and-right direction
Solution Approach 1:
The patent establishes asymmetric positioning requirements for the battery packs relative to the grip portion. The lateral center distance between battery packs is specifically controlled to be 0.02 to 0.2 times the lateral width of the grip portion, creating a balanced weight distribution that prevents lateral inclination while allowing flexible installation on the body housing.
Data Source
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AI summary
A chainsaw 10 includes a body housing 11, an elongated guide bar 21 projecting forward from the body housing 11, a saw-chain 22 mounted on the periphery of the guide bar 21 for rotation, an electric motor 23 mounted within the body housing for rotating, and a top handle 12 provided on an upper portion of the body housing above the guide bar and extending in a fore-and-aft direction. A plurality of rechargeable battery packs 31 is mounted on the body housing 11 as a source of power supply for the electric motor 23. The battery packs are mounted to the body housing in such a manner that a center of gravity G of the chainsaw observed from the back side is positioned in a two times extent R of lateral width of a gripe portion 12a of the top handle 12 at both sides of a vertical centerline of the gripe portion.