Reciprocating Power Tool Handle Vibration Isolation

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Solution Overview

Problem

Existing reciprocating power tools, such as hammer drills, are effective in reducing vibration transmitted to the handle in the axial direction of the tool bit but fail to adequately address vibration reduction in directions crossing the axial direction, leading to a need for improved vibration isolation.

Innovation Solution

A reciprocating power tool design featuring a handle connected to the tool body via an elastic member and a shaft that allows rotation around a transverse axis, with the elastic member and shaft positioned to absorb and redirect vibrations in both longitudinal and vertical directions, and a battery mounting system that displaces the center of gravity away from the tool bit axis to enhance vibration isolation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the handle is connected to the tool body via an elastic element in the axial direction only, then vibration in the axial direction is reduced, but vibration in directions crossing the axial direction is not adequately reduced

Engineering Contradiction:
Improvevibration transmission to handleVSAvoidvibration isolation coverage
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The invention transitions from a single-dimensional (axial) vibration isolation approach to a multi-dimensional approach by adding a rotation axis perpendicular to the axial direction. The handle can now rotate around a transverse axis in addition to moving axially, enabling the system to address vibrations in multiple directions simultaneously through combined axial and rotational degrees of freedom

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If the handle is rigidly connected to the tool body, then structural simplicity is maintained, but vibration is transmitted directly to the handle

Engineering Contradiction:
Improvevibration transmission to handleVSAvoidconnection structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention introduces an elastic element as an intermediary component between the tool body and handle. This elastic element serves as a mediator that selectively transmits and isolates vibrations, allowing the connection structure to reduce harmful vibrations while maintaining overall structural integrity and simplicity

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the battery is mounted on the axis of the tool bit, then the center of gravity is aligned with the tool bit axis, but vibration isolation in vertical direction is insufficient

Engineering Contradiction:
Improvevibration transmission to handleVSAvoidcenter of gravity position
Core Design Contradiction:
Object-affected harmful factorsVSShape

Solution Approach 1:

The invention deliberately positions the battery asymmetrically relative to the tool bit axis, placing it in an intermediate region between the driving mechanism and battery mounting part. This asymmetric positioning shifts the center of gravity away from the tool bit axis to a location that optimizes vibration isolation in both longitudinal and vertical directions, creating an unbalanced mass distribution that counteracts vibrations more effectively

Inventive Principle:
Principle #4Asymmetry

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 significantly reduces vibrations transmitted to the handle in both longitudinal and vertical directions, improving user comfort and tool stability during operation by effectively isolating tool body vibrations through the elastic member and strategic placement of the battery mounting part.

Implementation Method 1

The first connection part has an elastic member and connects one end region of the handle in the vertical direction and the tool body via the elastic member

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The second connection part has a shaft extending in the transverse direction and connects the other end region of the handle in the vertical direction and the tool body such that the handle can rotate around an axis of the shaft with respect to the tool body

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2808130B1Reciprocating power tool
Publication Date: 2019.03.27 MAKITA CORP
  • EP2808130B1 patent drawingFigure 1
  • EP2808130B1 patent drawingFigure 2

AI summary

A reciprocating power tool is provided which is improved in vibration isolation of the handle. The reciprocating power tool has a tool body 101 and a handle 109 connected to the tool body 101. When an axial direction of a tool bit is defined as a longitudinal direction, the handle 109 extends in a vertical direction crossing the longitudinal direction. Further, an upper region of the handle 109 is connected to the tool body 101 via an elastic member 171 and a lower region of the handle 109 is connected to the tool body 101 via a support shaft 181 such that it can rotate around an axis of the support shaft 181 in a transverse direction crossing both the longitudinal direction and the vertical direction with respect to the tool body 101. When the handle 109 rotates around the support shaft 181 with respect to the tool body 101, the elastic member 171 reduces vibration which is caused in the tool body 101 and transmitted to the handle 109.