Hammer Mechanism Handle Structure for Power Tool Vibration Damping
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Solution Overview
Problem
Rotary hammers experience vibrations in both axial and radial directions due to reaction forces and motion conversion mechanisms, which are transmitted to the handle, affecting user comfort and tool stability.
Innovation Solution
A power tool design with a handle that moves relative to the housing in the axial direction, guided by members and biased away from the output shaft, and incorporates elastic members to absorb vibrations, reducing radial rattling and axial vibrations through adjustable clearance and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the handle is positioned close to the housing to reduce radial rattling, then user comfort is improved, but vibration transmission in the axial direction increases
Solution Approach 1:
The handle is designed to be movable relative to the housing in the axial direction through guide members, allowing the radial distance to dynamically adjust between a first distance (reducing radial rattling) and a second distance (reducing axial vibration transmission) based on operational conditions
2Object-affected harmful factors
If elastic members are used to reduce axial vibration transmission, then vibration damping is improved, but device complexity increases
Solution Approach 1:
Elastic members are introduced as intermediary elements between the handle and housing to absorb and damp axial vibrations, reducing the transmission of harmful vibrations to the user while maintaining structural integrity
Solution Approach 2:
The biasing force of the elastic members is optimized to provide sufficient damping effect while minimizing the impact on overall device complexity, achieving a balance between vibration reduction and structural simplicity
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
Enhances user comfort by minimizing radial rattling and axial vibrations, improving the overall feel and stability of the power tool during operation.
Implementation Method 1
a biasing member configured to bias the handle away from the final output shaft in the axial direction
Implementation Method 2
at least one guide member disposed between the housing and the handle so as to extend in the axial direction and configured to slidably guide the relative movement between the handle and the housing
Implementation Method 3
radial rattling between the handle and the housing, provided that a clearance is secured between the handle and the motor housing. Especially, the rotary hammer disclosed in Japanese Patent Application Laid-Open No. 2022-128006 includes elastic members disposed between the handle and the motor housing, and therefore can effectively reduce the transmission of the vibration in the direction intersecting with the axial direction to the handle
Data Source
AI summary
A power tool having a hammer mechanism includes a final output shaft configured to removably hold a tool accessory and defining a driving axis of the tool accessory, a housing, and a handle movable relative to the housing in an axial direction of the driving axis. The housing and the handle at least partially have such a shape that a radial distance between the housing and the handle is shorter when the handle is located at a first relative position maximally separated from the housing in the axial direction than when the handle is located at a second relative position close to the housing in the axial direction.