Fastener Tool Feeder Retention Device

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Solution Overview

Problem

Existing fastener driving tools face issues with nail jams and unsatisfactory nail drives due to improper timing relationships between the drive piston and feeder mechanism during the return cycle, leading to friction and interference with the driver blade, which can be exacerbated by dirt and debris.

Innovation Solution

The implementation of an electromechanical retention device that holds the feed piston in a retracted position until the drive piston has returned to its pre-firing position, using a gas conduit to overcome the return spring and an electromagnet to ensure the feed piston remains retracted until the driver blade is clear, thus preventing side loading and ensuring proper nail advancement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the feed piston advances the fastener toward the nosepiece during the drive piston return cycle, then the fastener can be positioned for driving, but the fastener becomes biased against the driver blade causing friction and prolonged return time

Engineering Contradiction:
Improvefastener driving speedVSAvoiddriver blade return time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The feed piston is retracted in advance during the drive piston downward stroke, positioning the fastener feeder mechanism ready for the next cycle. This preliminary retraction ensures that when the driver blade returns, the fastener is already positioned without being biased against the blade, eliminating friction delays.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention introduces a dynamic control mechanism that adjusts the feed piston timing based on the drive piston position. The feed piston is held in the retracted position until the drive piston reaches a predetermined position, then automatically advances the fastener. This dynamic coordination optimizes the timing relationship between the two pistons, preventing fastener biasing while maintaining high driving speed.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If the feed piston retracts using gas pressure from the combustion cycle, then the feeder mechanism can be powered, but the gas conduit must be precisely positioned to establish correct timing relationships

Engineering Contradiction:
Improvefeeder mechanism simplicityVSAvoidgas conduit positioning accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The invention replaces the purely mechanical gas pressure-driven feed piston with an electromechanical system. An electromagnetic actuator controls the feed piston position, eliminating the need for precise gas conduit positioning. This substitution maintains feeder mechanism simplicity while significantly reducing manufacturing precision requirements for the gas conduit.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If the driver blade returns to pre-firing position before the feed piston advances the fastener, then the fastener can be advanced without interference, but the return spring may cause premature fastener advancement

Engineering Contradiction:
Improvefastener driving reliabilityVSAvoidtiming control mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention implements a feedback control system that monitors the drive piston position and automatically controls the feed piston timing. When the drive piston reaches the predetermined position during its return stroke, the system activates the feed piston to advance the fastener. This feedback mechanism ensures reliable timing coordination without requiring complex mechanical timing adjustments.

Inventive Principle:
Principle #23Feedback

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 reduces nail malfunctions, improves piston return speed and reliability, increases operational life, and enhances energy efficiency while being lightweight and resistant to dirt and debris, maintaining user-applied force requirements.

Implementation Method 1

a gas conduit that receives a supply of compressed gas from the power source and transmits the compressed gas to the feed cylinder to overcome the return spring and retract the feed piston

Methodology Applied
Scientific EffectCompressed gas: Pressure Increase

Implementation Method 2

an electromagnet to hold the feed piston in the retracted position until the driver blade is clear

Methodology Applied
Scientific EffectElectromagnet: Electromagnet

Data Source

PatentEP2162264B1Fastener driving tool with feeder mechanism retention device
Publication Date: 2020.05.06 ILLINOIS TOOL WORKS INC
  • EP2162264B1 patent drawingFigure 1
  • EP2162264B1 patent drawingFigure 2
  • EP2162264B1 patent drawingFigure 3

AI summary

A fastener driving tool (10) includes a power source (14) including a reciprocating driver blade (24), a tool nose (30) associated with the power source for receiving the driver blade for driving fasteners (26) fed into the nose, a magazine (32) constructed and arranged to house a supply of the fasteners, a magazine feeder mechanism (50) associated with the magazine for sequentially feeding fasteners into the nose, the feeder mechanism including a reciprocating feed piston (58), and an electromechanical retention device (110) that is operationally associated with the feeder mechanism (50) and configured for retaining the feed piston (58) in a retracted position until the driver blade is positioned to allow fastener advancement into the nose.