Rotary Hammer Handle Vibration Isolation via Segmented Housing

Solution Overview

Problem

The existing rotary hammer designs face challenges in efficiently transmitting drive torque and preventing vibration transmission to the main handle, leading to increased costs and potential loss of torque due to the use of specialized bellow-like transmitting members.

Innovation Solution

A power tool design featuring a motor with an output shaft parallel to the tool bit, a driving mechanism connected to the motor, a main body housing the motor and mechanism, a movable main handle guided by a guide element, and a biasing member that biases the handle in the longitudinal direction, eliminating the need for a specialized transmitting member and reducing vibration transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a specially formed bellow-like transmitting member is used to allow relative movement between housing units and transmit drive torque, then the relative movement is enabled, but the price of the rotary hammer becomes expensive and loss of transmission of drive torque increases

Engineering Contradiction:

Improverelative movement capabilityVSAvoiddrive torque transmission loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The housing is divided into multiple housing units that can move relative to each other, with each unit containing specific components. This segmentation allows the drive unit and transmission unit to move independently while maintaining torque transmission through simple structural connections rather than complex bellow-like members.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The housing units serve multiple functions: they provide structural support, enable relative movement for vibration isolation, and transmit drive torque through their interconnected structure. This multi-functionality eliminates the need for specialized bellow-like transmitting members that would add cost and energy loss.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If a specially formed bellow-like transmitting member is used to transmit drive torque during relative movement, then torque transmission is maintained, but the device complexity increases

Engineering Contradiction:

Improvedrive torque transmissionVSAvoidtransmitting member complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The housing is divided into multiple housing units that can move relative to each other, with each unit containing specific components. This segmentation allows the drive unit and transmission unit to move independently while maintaining torque transmission through simple structural connections rather than complex bellow-like members.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The housing units serve multiple functions: they provide structural support, enable relative movement for vibration isolation, and transmit drive torque through their interconnected structure. This multi-functionality eliminates the need for specialized bellow-like transmitting members that would add cost and energy loss.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If the main handle is fixed to the main body, then structural simplicity is maintained, but vibration transmission from the main body to the main handle increases

Engineering Contradiction:

Improvehandle structure simplicityVSAvoidvibration transmission to handle

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The main handle is made movable with respect to the main body through guide elements, transforming the static fixed connection into a dynamic movable connection. This allows the handle to move in response to vibrations while being constrained by guide elements, reducing vibration transmission to the user's hand while maintaining structural simplicity.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The guide elements act as intermediary components between the main body and the main handle, allowing controlled movement while guiding the handle's motion. This intermediary structure reduces direct rigid coupling, thereby reducing vibration transmission while maintaining ease of manufacture.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This design effectively transmits motor rotation to the driving mechanism while minimizing vibration transmission to the main handle, improving usability and reducing costs by eliminating the need for specialized transmitting members.

Implementation Method 1

a biasing member which is arranged between the main body and the main handle and biases the main body and the main handle in the longitudinal direction of the tool bit

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS9815185B2Power tool

Publication Date: 2017.11.14 MAKITA CORP

AI summary

A hammer drill (101) comprises a main body (103) which houses a driving motor (110) and a driving mechanism and a handle (109) which is movable to the main body (103). Further, a coil spring (160) which biases the handle (109) is provided. In a state that the coil spring (160) biases the handle (109), the handle (109) is moved against the main body (103) in a longitudinal direction of a hammer bit (119) and vibration transmission from the main body (103) to the handle (109) is prevented.