Bulk Metallic Glass Drive Elements for Wear-Resistant Power Tools

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Solution Overview

Problem

Power tools such as hammer drills and fastener drivers experience significant wear and strain in their components due to high-impact engagements, particularly in ratchet plates made of crystalline metals, leading to reduced durability and efficiency.

Innovation Solution

Implementing drive elements and other components in power tools with amorphous metal materials, specifically bulk metallic glass, which offers high yield strength and elastic modulus, reducing wear and enhancing durability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If crystalline metal components are used in drive elements, then the components can be manufactured with conventional processes, but the components suffer from significant wear and strain under high-impact engagements

Engineering Contradiction:

Improvedurability of drive elementsVSAvoidmanufacturing complexity of amorphous metal components

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the material parameters by transitioning from crystalline metal to amorphous metal (bulk metallic glass), which fundamentally alters the material structure to eliminate grain boundaries and dislocations. This parameter change enables the drive elements to withstand high-impact engagements with superior elasticity and wear resistance, directly resolving the durability issue while the molding process handles the manufacturing aspect

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs amorphous metal as a distinct material phase with different structural properties compared to conventional crystalline metals. This material substitution creates a composite-like performance improvement where the amorphous structure provides enhanced elastic properties and wear resistance, solving the reliability problem while maintaining manufacturability through specialized molding techniques

Inventive Principle:

Principle #40Composite materials

2Reliability

If amorphous metal material is used in drive elements, then wear resistance and durability are improved, but the manufacturing process becomes more complex

Engineering Contradiction:

Improvewear resistance of drive elementsVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces conventional mechanical manufacturing processes (machining, forming) with a molding process specifically adapted for amorphous metal materials. This substitution enables the complex geometry of drive elements with sliding contact surfaces to be manufactured directly in the desired shape, achieving superior wear resistance through the amorphous structure while simplifying the overall manufacturing workflow through near-net-shape molding

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Strength

If conventional crystalline metals are used in ratchet plates, then the components can withstand impact forces, but the components experience strain and wear after extended use

Engineering Contradiction:

Improveimpact resistance of ratchet platesVSAvoidservice life of ratchet plates

Core Design Contradiction:

StrengthVSDuration of action of stationary object

Solution Approach 1:

The patent changes the fundamental material parameters by using amorphous metal instead of crystalline metal for ratchet plates. The amorphous structure eliminates grain boundaries and dislocation mechanisms that cause wear in crystalline materials, while maintaining high strength to withstand impact forces. This parameter change enables the ratchet plates to resist both impact forces and prolonged wear, extending service life significantly

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent incorporates sliding contact surfaces with optimized curvature on the ratchet plates. The curved surfaces distribute contact stresses more evenly during engagement, reducing stress concentrations that would otherwise accelerate wear. This geometric optimization, combined with the amorphous material structure, enhances both impact resistance and durability of the ratchet plates

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS12479076B2Bulk metallic glass components for a power tool

Publication Date: 2025.11.25 MILWAUKEE ELECTRIC TOOL CORP

AI summary

A power tool includes a drive mechanism, a housing enclosing at least a portion of the drive mechanism, a spindle rotatable in response to receiving torque from the drive mechanism, a first drive element coupled for co-rotation with the spindle, the first drive element including a first sliding contact surface, and a second drive element rotationally fixed to the housing, the second drive element including a second sliding contact surface engageable with the first sliding contact surface while the spindle rotates. At least one of the first drive element or the second drive element includes an amorphous metal material.