Hammer Mechanism Handle Biasing to Suppress Power Tool Tilting
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Solution Overview
Problem
Power tools with hammer mechanisms experience significant vibration along the driving axis, leading to tilting during machining operations due to the handle's lower end being a free end and the imbalance of biasing forces.
Innovation Solution
A power tool design with a handle offset downward relative to the driving axis, utilizing biasing members with varying forces, where the biasing force closer to the grip part is stronger than further away, stabilizing the tool's attitude during machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the handle is elastically connected to the tool body by biasing members to reduce vibration transmission, then vibration isolation is improved, but the handle easily tilts during machining operation due to imbalance
Solution Approach 1:
The patent applies asymmetry by configuring the biasing members with different biasing forces based on their position relative to the driving axis. Specifically, biasing members arranged below the driving axis (closer to the grip part) have larger biasing forces, while those arranged above the driving axis have smaller biasing forces. This asymmetric force distribution counteracts the tilting moment and stabilizes the handle attitude during machining operation, while maintaining the vibration isolation benefits of elastic connection.
Solution Approach 2:
The patent implements local quality by varying the biasing force characteristics of different biasing members according to their specific positions. Each biasing member is designed with appropriate stiffness and force characteristics tailored to its location - stronger biasing forces are provided where needed (below the driving axis) to prevent tilting, while maintaining overall elastic connection for vibration reduction. This localized optimization resolves the contradiction between vibration isolation and handle stability.
2Ease of operation
If the grip part is arranged below the driving axis with a free end lower end, then ease of operation is improved, but the handle tilts in a direction toward the workpiece during machining
Solution Approach 1:
The patent uses the biasing members as counterbalancing elements that generate opposing forces to counteract the tilting moment caused by the offset grip part. The biasing members, particularly those below the driving axis with larger biasing forces, create a counterbalancing effect that prevents the handle from tilting toward the workpiece, thereby maintaining handle attitude stability while preserving the ergonomic benefits of the offset grip configuration.
3Device complexity
If biasing members are arranged symmetrically above and below the driving axis, then structural balance is improved, but tilting suppression is insufficient due to equal biasing forces
Solution Approach 1:
The patent deliberately breaks the symmetry of biasing member arrangement by configuring biasing members below the driving axis with larger biasing forces than those above the driving axis. This asymmetric force distribution is specifically designed to counteract the tilting moment generated by the offset grip part, providing effective tilting suppression while maintaining a relatively simple overall structure with biasing members positioned at standard locations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively suppresses tilting of the power tool by ensuring the handle remains stable, enhancing operational stability and reducing vibration transmission.
Implementation Method 1
The biasing members are configured to elastically connect the tool body and the handle and bias the tool body and the handle in directions away from each other in the front-rear direction
Implementation Method 2
A biasing force of the at least one second biasing member is larger than a biasing force of the at least one first biasing member, which means that a biasing force on the side close to the grip part is larger than a biasing force on the side far from the grip part. This suppresses tilting of the handle during machining operation
Data Source
AI summary
A power tool having a hammer mechanism has a tool body that houses a motor and a driving mechanism and extends in a front-rear direction; a handle including a grip part that extends in an up-down direction orthogonal to the front-rear direction behind the tool body and has a lower end formed as a free end and is arranged below the driving axis; and a plurality of biasing members configured to elastically connect the tool body and the handle. The biasing members include at least one first biasing member arranged above the driving axis in the up-down direction, and at least one second biasing member arranged below the driving axis in the up-down direction. In this power tool, a biasing force of the at least one second biasing member is larger than a biasing force of the at least one first biasing member.