Offset Roller Rotary Lifter for Powered Fastener Driver Blade Return

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing powered fastener drivers face inefficiencies in returning the driver blade from the bottom-dead-center position to the top-dead-center position, often requiring external air pressure and complex mechanisms, which can lead to stress on components and reduced operational efficiency.

Innovation Solution

A gas spring-powered fastener driver with a rotary lifter mechanism, featuring a drive pin and offset center of gravity, that receives torque from a drive unit to efficiently return the driver blade from the bottom-dead-center position to the top-dead-center position, utilizing a roller with specific engagement sections and a center of gravity offset from the rotational axis to facilitate smooth movement and reduce stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If external air pressure and complex mechanisms are used to return the driver blade, then the driver blade can be returned from bottom-dead-center to top-dead-center position, but the mechanism complexity increases and component stress increases

Engineering Contradiction:

Improvedriver blade return operationVSAvoidlifter mechanism complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the essential function of returning the driver blade by removing complex external air pressure systems and retaining only the critical roller and cam interaction, thereby simplifying the overall mechanism while maintaining operational effectiveness

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using complex mechanisms to push the driver blade upward, the invention inverts the approach by using the downward motion itself to drive the cam, which then passively returns the driver blade through the roller-cam interaction, eliminating the need for active return mechanisms

Inventive Principle:

Principle #13The other way round (Inversion)

2Ease of operation

Engineering Contradiction:

Improvedriver blade return operationVSAvoidcomponent stress

Core Design Contradiction:

Ease of operationVSStress or pressure

Solution Approach 1:

The invention converts the harmful stress and complexity of external air pressure systems into a beneficial passive mechanical interaction where the cam profile naturally guides the roller, transforming potential stress points into smooth, controlled motion paths

Inventive Principle:

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

Solution Approach 2:

The lifter mechanism serves itself by using the driver blade's own downward motion to rotate the cam, which in turn automatically returns the driver blade without requiring external power sources or additional actuation systems, thereby eliminating stress associated with complex powered mechanisms

Inventive Principle:

Principle #25Self-service

3Productivity

If a roller with offset center of gravity is used in the lifter mechanism, then the driver blade return efficiency increases, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvedriver blade return efficiencyVSAvoidroller center of gravity positioning

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent intentionally introduces asymmetry by offsetting the roller's center of gravity from its rotational axis, creating an unbalanced roller that generates beneficial dynamic effects during rotation, thereby improving driver blade return efficiency through controlled vibrational or impact characteristics

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The invention changes the physical parameter of the roller by deliberately positioning its center of gravity at an offset distance from the rotational axis, transforming a standard balanced roller into an unbalanced roller that provides enhanced return functionality while managing manufacturing precision through defined offset parameters

Inventive Principle:

Principle #35Parameter changes

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 solution enables efficient and stress-reduced operation by using a gas spring principle, eliminating the need for external air pressure and simplifying the mechanism, enhancing the driver blade's return efficiency and reducing component stress, thereby improving overall fastener driving cycles.

Implementation Method 1

the roller includes a center of gravity that is offset from the rotational axis

Methodology Applied

Scientific EffectGravitational force: Gravitation

Data Source

PatentUS12083659B2Unbalanced roller on lifting mechanism

Publication Date: 2024.09.10 MILWAUKEE ELECTRIC TOOL CORP

AI summary

A powered fastener driver includes a driver blade movable from a top-dead-center (TDC) position to a driven or bottom-dead-center (BDC) position for driving a fastener into a workpiece. The driver blade also includes a tooth defining an end portion. A drive unit provides torque to move the driver blade from the BDC position toward the TDC position. A rotary lifter is engageable with the driver blade and is configured to receive torque from the drive unit to return the driver blade from the BDC position toward the TDC position. The lifter has a drive pin and a roller positioned on and rotatable relative to the drive pin about a rotational axis. The roller includes a center of gravity that is offset from the rotational axis.