Flywheel Nailer Return System for Driver Blade Recoil Control

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Solution Overview

Problem

Existing fastening tools, such as nailers, suffer from unreliable fastener driving performance, damage to moving parts, undesired driver blade recoil, misfires, and spring failure, especially during high-energy and high-speed operations, limiting their effectiveness and efficiency in driving fasteners into various materials.

Innovation Solution

A high inertia driver system utilizing a flywheel mechanism with a return system that includes a return spring and bumpers to control recoil energy, preventing unintentional fastener driving and extending the tool's operational life by reducing spring failure, capable of driving fasteners into diverse materials including concrete and metal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high energy and high-speed driving is used to improve fastener driving performance, then driving capability is improved, but reliability deteriorates due to damage to moving parts and spring failure

Engineering Contradiction:

Improvefastener driving performanceVSAvoidmoving parts durability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A bumper is positioned to receive the driver blade during its return stroke, cushioning the impact before it can damage the nosepiece assembly or other moving parts. This preventive cushioning allows high-speed operation while protecting components from damage that would reduce reliability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Duration of action of moving object

If return spring is used to enable driver blade return, then operational continuity is improved, but reliability deteriorates due to spring failure

Engineering Contradiction:

Improveoperational continuityVSAvoidspring reliability

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

The bumper cushions the driver blade return stroke, reducing the stress and impact forces on the return spring. This decreases the rate of spring fatigue and failure, extending spring life and maintaining operational continuity without compromising reliability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The bumper converts the harmful high-impact return stroke into a beneficial controlled deceleration process. The impact energy that would otherwise damage the spring is instead absorbed by the bumper, allowing the spring to operate within safer stress limits while maintaining its return function.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Device complexity

If driver blade recoil is not controlled, then operational simplicity is maintained, but reliability deteriorates due to unintentional fastener driving

Engineering Contradiction:

Improvereturn system complexityVSAvoidfastener driving accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The bumper is positioned to intercept the driver blade during its return stroke, preliminarily controlling the blade's motion before it can accidentally strike another fastener. This preliminary action prevents misfires and unintended fastener driving while adding minimal complexity to the return system.

Inventive Principle:

Principle #10Preliminary action

4Ease of operation

If mechanical return springs are used in cordless nailer, then portability is improved, but reliability deteriorates due to spring failure requiring tool replacement or repair

Engineering Contradiction:

Improvetool portabilityVSAvoidspring longevity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The bumper provides beforehand cushioning to the driver blade return, reducing impact forces on the return spring. This extends spring life and reduces failures that would require tool replacement or repair, while maintaining the portability benefits of mechanical springs in cordless nailers.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 high inertia driver system provides reliable fastener driving with reduced spring failure, enhancing tool longevity and efficiency, allowing for consistent operation across different materials and power sources, including cordless and powered nailers.

Implementation Method 1

an electric motor that drives a flywheel to contact a driver blade to drive a fastener into a workpiece

Methodology Applied

Scientific EffectRotational energy storage: Flywheel

Implementation Method 2

The return system can use a return spring and one or more bumpers that control the recoil energy of the driver blade after driving a fastener into a workpiece

Methodology Applied

Scientific EffectElastic potential energy: Spring

Implementation Method 3

one or more bumpers that control the recoil energy of the driver blade after driving a fastener into a workpiece

Methodology Applied

Scientific EffectImpact absorption: Impact Force

Data Source

PatentUS12502756B2High inertia driver system

Publication Date: 2025.12.23 BLACK & DECKER CORP

AI summary

A high inertia driver system for a fastening tool having an electric motor that drives a flywheel to contact a driver blade to drive a fastener into a workpiece. The high inertia driver system also has a return system which prevents the unintentional driving of a second fastener. The return system uses a return spring that controls the recoil energy of the driver blade after driving a fastener into a workpiece. The system achieves a long operational life for the fastening tool by increasing the number of return cycles of the driver blade free of a return spring failure.