Tool Fitting Sealing Lip Structure for Dust and Vibration

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Solution Overview

Problem

Existing power tool fitting devices, particularly those used with chipping hammers, inadequately prevent dust penetration, leading to abrasive wear and accelerated component degradation due to vibration and dust interaction.

Innovation Solution

A dust protection device with a first and second dust stripping element, a fixing bead, and a sealing lip element, positioned to effectively seal against dust penetration, and designed to accommodate vibration without collision, using flexible materials and specific cross-sectional shapes for enhanced sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a simple dust protection device is used, then the device complexity is low, but the sealing effectiveness against dust penetration is insufficient

Engineering Contradiction:

Improvedust penetrationVSAvoiddust protection device structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The dust protection device is segmented into multiple functional elements: a dust stripping element for initial dust removal, a sealing lip element for primary sealing, and a retention element for securing the assembly. This segmentation allows each element to perform its specific function effectively, improving overall dust protection without creating an overly complex monolithic structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sealing lip element is made from a flexible material that can deform and adapt to the contours of the tool shank and housing. This flexibility enables the sealing lip to maintain effective contact and sealing under various conditions including vibration and thermal expansion, providing reliable dust protection while keeping the device structure relatively simple.

Inventive Principle:

Principle #30Flexible shells and thin films

2Reliability

If the sealing lip element is made rigid for stable sealing, then the sealing position is stable, but the sealing effectiveness under vibration conditions deteriorates

Engineering Contradiction:

Improvesealing contact stabilityVSAvoiddust penetration under vibration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The sealing lip element's material parameters are specifically selected to exhibit viscoelastic properties that allow it to adapt its rigidity based on operating conditions. Under static conditions, the material maintains sufficient rigidity for stable sealing contact. Under vibration conditions, the material's flexibility increases, allowing it to absorb vibrations and maintain sealing effectiveness, thus resolving the contradiction between stability and vibration resistance.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If the dust stripping element is positioned close to the holding device, then the sealing effectiveness is improved, but the risk of collision and damage under vibration increases

Engineering Contradiction:

Improvedust sealing effectivenessVSAvoiddust stripping element durability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The dust stripping element is positioned to perform preliminary dust removal action before the sealing lip element engages with the tool shank. This preliminary action creates a dust-free zone that reduces the burden on the sealing lip, allowing it to focus on maintaining the primary seal. The positioning and timing of this preliminary action are optimized to prevent collisions while maintaining effectiveness.

Inventive Principle:

Principle #10Preliminary action

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

Prevents dust ingress into the tool fitting device, reducing abrasive wear and component failure by ensuring continuous sealing contact despite vibrations, thus prolonging the tool's lifespan.

Implementation Method 1

the sealing lip element (24) comprises a cross-sectional area that tapers in the radial direction. This ensures high deformability and flexibility of the sealing lip element (24) and secures contact with the holding device (11) for the purpose of sealing against penetrating dust

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

there is always at least one dust stripping element resting against the tool shank and therefore counteracting the penetration of dust into the interior of the tool fitting device

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS12454015B2Sealing lip on tool fitting

Publication Date: 2025.10.28 HILTI AG

AI summary

Tool fitting device for a power tool, in particular a chipping hammer, including—a holding device for receiving and holding a tool shank, a retention element extending at least around a section or sections of the holding device, and a dust protection device for preventing the penetration of dust into the tool fitting device. The dust protection device includes at least one first dust stripping element, at least one fixing bead, and at least one sealing lip element, wherein the sealing lip element is positioned in front of the retention element in the axial direction. Dust protection device for use in a tool fitting device.