Single Switch Dual Firing Combustion Nailer Control

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Solution Overview

Problem

Conventional combustion nailers require sequential operation due to manual control of the valve sleeve, limiting their ability to achieve repetitive firing conditions efficiently, as the operator's muscle response time affects the combustion chamber closure and piston return, leading to inefficiencies in fastener driving.

Innovation Solution

A single switch controls ignition and activates a fan motor, with a microprocessor-timed combustion chamber control device ensuring the chamber remains closed until the piston returns, allowing for seamless transition between sequential and repetitive firing conditions without additional switch manipulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a manual lockout mechanism is used to control the valve sleeve, then the combustion chamber can be securely closed before ignition, but the tool is limited to sequential operation and cannot achieve repetitive firing

Engineering Contradiction:
Improvecombustion chamber closure reliabilityVSAvoidfiring rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the manual mechanical lockout mechanism with an electronic control system. A microprocessor-based controller uses sensors to detect piston position and automatically controls an electromagnetic valve sleeve actuator, eliminating the need for manual operation and enabling automated repetitive firing cycles.

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

Solution Approach 2:

The system automatically monitors its own state through sensors that detect piston position and combustion chamber closure status. The microprocessor uses this feedback to automatically control the valve sleeve actuator and ignition timing, allowing the tool to self-regulate and achieve repetitive firing without manual intervention.

Inventive Principle:
Principle #25Self-service

2Reliability

If the combustion chamber is kept closed longer than minimum time, then piston return is ensured, but cooling and purging of the tool is prevented

Engineering Contradiction:
Improvepiston return assuranceVSAvoidcombustion chamber cooling
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

Sensors continuously monitor piston position and combustion chamber status, providing real-time feedback to the microprocessor. The controller uses this feedback to precisely control the duration of chamber closure, ensuring sufficient time for piston return while automatically opening the chamber to enable cooling and purging cycles.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the combustion chamber closure duration based on real-time detection of piston position and combustion status. The electromagnetic valve sleeve actuator can open or close the chamber at optimized moments, allowing the system to adapt the closure time to balance piston return requirements with cooling needs.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If two electrical switches are required for ignition control, then sequential operation is controlled, but the device complexity increases and repetitive firing cannot be achieved

Engineering Contradiction:
Improvesequential operation controlVSAvoidswitch configuration
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The microprocessor-based control system performs multiple functions through a single integrated controller. It manages combustion chamber closure detection, piston position monitoring, ignition timing control, and valve sleeve actuation, eliminating the need for separate electrical switches and reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the functions of multiple electrical switches and manual controls into a single electronic control system. The microprocessor integrates detection and control functions, using sensors and an electromagnetic actuator to manage both sequential and repetitive firing modes through one unified control architecture.

Inventive Principle:
Principle #5Merging (Combining)

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

Enables efficient repetitive firing by ensuring consistent piston return and maintaining combustion chamber closure, reducing operator dependency on muscle response time and improving overall tool operation efficiency.

Implementation Method 1

a fan motor for facilitating fuel mixing, scavenging

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

a combustion chamber control device energized simultaneously with the pulling of the trigger. However, the combustion chamber is not controlled until the combustion chamber is closed

Methodology Applied
Scientific EffectElectromagnetism: Electromagnet

Data Source

PatentEP2414135B1Single switched dual firing condition combustion nailer
Publication Date: 2018.05.16 ILLINOIS TOOL WORKS INC
  • EP2414135B1 patent drawingFigure 1
  • EP2414135B1 patent drawingFigure 2
  • EP2414135B1 patent drawingFigure 3

AI summary

A combustion tool (10) is provided, including a combustion power source (14) with a reciprocating valve sleeve (36) moving between a rest position in which a combustion chamber (18) is open, and a closed position in which the combustion chamber is sealed, a control system (66) operatively connected to the power source, and a trigger switch (26) connected to the control system and providing operator interface with the control system. The control system is configured such that operator manipulation of the trigger switch is the only operator initiated movement required for initiating repetitive spark generation.