Segmented Bellows Vibration Damping in Hammer Drills

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Solution Overview

Problem

Existing hammer drill designs face challenges in minimizing vibration transfer to the operator's hands due to the complexity and cost associated with movement coordination mechanisms, and the expansion and contraction of bellows in previous designs affect the biasing characteristics and lead to wear and tear.

Innovation Solution

The use of bellows with end portions slidably engaging the housing and rear handle, where at least one end is fixed or integrally formed, and a compressible portion between the ends, reduces the need for significant compression and expansion, minimizing wear and altering biasing characteristics, and allowing for robust construction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If bellows are used to connect the rear handle to the body, then vibration damping is achieved, but the bellows expand and contract significantly causing wear and tear

Engineering Contradiction:

Improvevibration transfer to operator's handsVSAvoidwear and tear of bellows

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The bellows is divided into three distinct sections: a first end portion connected to the body, a second end portion connected to the rear handle, and an intermediate compressible portion between them. This segmentation allows the end portions to remain relatively stable while only the intermediate portion compresses and expands during vibration damping, significantly reducing wear on the connection points.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the bellows are designed with different functional characteristics. The end portions are designed for stable connection with minimal movement, while the intermediate portion is designed to be compressible and expandable to absorb vibrations. This local differentiation of functionality reduces overall wear and tear while maintaining vibration damping effectiveness.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If bellows are used to dampen vibrations, then vibration reduction is achieved, but the biasing characteristics are compromised

Engineering Contradiction:

Improvevibration transfer to operator's handsVSAvoidbiasing characteristics

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The bellows is segmented into stable end portions and a compressible intermediate portion. This segmentation isolates the biasing mechanism at the ends from the compression/expansion actions in the intermediate portion, allowing the biasing characteristics to remain stable while still achieving vibration damping through the compressible section.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bellows structure provides different local properties: the end portions maintain stable biasing characteristics for reliable positioning, while the intermediate portion provides compressibility for vibration absorption. This local quality differentiation resolves the contradiction between maintaining biasing stability and achieving vibration reduction.

Inventive Principle:

Principle #3Local quality

3Object-affected harmful factors

If movement coordination mechanism is placed within the housing, then vibration damping is achieved, but valuable space is taken up

Engineering Contradiction:

Improvevibration transfer to operator's handsVSAvoidspace occupied in housing

Core Design Contradiction:

Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The movement coordination mechanism is merged with the rear handle structure itself, specifically integrating the bellows connection directly into the handle assembly. This eliminates the need for separate coordination mechanisms within the housing, reducing space occupation while maintaining vibration damping functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The bellows acts as an intermediary element between the housing and the rear handle, providing both movement coordination and vibration damping functions. By placing this intermediary mechanism at the handle connection point rather than within the housing, space is conserved while the required vibration damping and coordination functions are maintained.

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 solution effectively dampens vibrations without compromising the biasing characteristics, reducing wear and tear, and allowing for a more robust and cost-effective vibration reduction mechanism in hammer drills.

Implementation Method 1

The bellows is capable of compression and expansion to accommodate movement of the rear handle relative to the body and thereby dampen vibrations

Methodology Applied

Scientific EffectVibration damping: Damping

Implementation Method 2

a biasing device which biases the rear handle away from the body

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP2551060B1Power tool

Publication Date: 2014.09.24 BLACK & DECKER CORP

Figure 1
Figure 2~3

AI summary

A hammer drill having a housing (2) and a rear handle (4) moveably mounted to a rear of the housing by means of at least one movement control mechanism is disclosed. A bellows (152) is fixed to the handle and slidably mounted to a protrusion (204) on the housing to prevent access to the movement control mechanism.