Offset Spur Gear Counterweighting for Low-Vibration Reciprocating Tools
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Solution Overview
Problem
Reciprocating mechanisms in power tools generate vibration due to acceleration/deceleration at extreme ends of travel, affecting tool operation, user precision, and causing fatigue, especially at increased speeds and stroke lengths.
Innovation Solution
A reciprocating power tool with a parallel axis transmission that includes a gear shaft with offset spur gears, driving a reciprocating device and a counterbalancing device, where the counterbalancing device moves opposite to the reciprocating device to balance forces, reducing vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If operational speed and stroke length of the output spindle are increased, then productivity is improved, but vibration is generated due to acceleration/deceleration at extreme ends of travel
Solution Approach 1:
The patent applies a counterbalancing mechanism with a counterweight that moves in opposition to the reciprocating mechanism. The counterweight is connected through a transmission system including a gear shaft with offset spur gears, creating a balancing force that counteracts the vibration generated during high-speed reciprocating operation, thereby allowing increased productivity without excessive vibration
2Productivity
If a reciprocating mechanism is provided to convert rotational force to linear force, then productivity is improved, but vibration is generated due to acceleration/deceleration at extreme ends of travel
Solution Approach 1:
The patent implements a counterbalancing mechanism where a counterweight moves in opposition to the reciprocating mechanism through a transmission system. This counterweight generates a balancing force that counteracts the vibration produced during force conversion operations, enabling the reciprocating mechanism to maintain productivity without excessive vibration
Solution Approach 2:
The patent combines the reciprocating mechanism and counterbalancing mechanism into a single integrated transmission system sharing a common gear shaft. This merging of functions allows both the productive reciprocating motion and the vibration-reducing counterbalancing motion to operate simultaneously from a single rotational input
3Ease of operation
If tool profile is made more compact, then ease of operation is improved for accessing confined spaces, but device complexity increases due to transmission and counterbalancing mechanisms
Solution Approach 1:
The patent combines the reciprocating mechanism and counterbalancing mechanism into a single integrated transmission system that shares a common gear shaft and housing. This merging reduces the overall space required compared to separate mechanisms, enabling a more compact tool profile that can access confined spaces while maintaining both reciprocating function and vibration reduction
Data Source
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AI summary
A reciprocating power tool includes a transmission that converts rotational force from a motor to linear forces output by a reciprocating device and a counterbalancing device. The transmission is a parallel axis transmission including a first gear portion and a second gear portion formed on a gear shaft, with the first gear portion and the second gear portion rotating together about a first rotational axis. The first gear portion rotates a first output gear and the second gear portion rotates a second output gear about a second rotational axis that is parallel to and offset from the first rotational axis. The first output gear drives the reciprocating device and the second output gear drives the counterbalancing device. The reciprocating device reciprocates linearly and the counterbalancing devices performs a linear reciprocating movement that is opposite that of the reciprocating device to counterbalance forces generated by operation of the reciprocating device.