Adjustable Overpressure Combustion Driving Tool

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Solution Overview

Problem

Existing driving tools lack flexibility in adjusting driving energy, as they typically rely on fixed overpressure levels, limiting their efficiency and adaptability.

Innovation Solution

Incorporation of a valve member that allows adjustable overpressure control in the combustion chamber, enabling continuous adjustment of driving energy through a switching valve, pressure sensor, or adjustable pressure relief valve, and an electric drive for piston compression, along with an optional external compressor for enhanced overpressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed overpressure level is used in the combustion chamber, then the device structure is simple, but the driving energy adjustment flexibility is limited

Engineering Contradiction:
Improvedriving energy adjustment flexibilityVSAvoiddevice structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by making the previously fixed overpressure level adjustable. A valve member is introduced to dynamically control the compression ratio of the fuel gas mixture in the combustion chamber, allowing the driving energy to be adjusted according to different working conditions. This transforms the static system into a dynamic one, resolving the contradiction between simplicity and flexibility.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the compression ratio parameter of the fuel gas mixture. Through the valve member, the compression ratio can be varied to change the overpressure level in the combustion chamber, thereby adjusting the driving energy. This directly addresses the need for flexibility while maintaining a relatively simple structural approach.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If an adjustable valve member is added to control overpressure, then driving energy flexibility is improved, but the device complexity increases

Engineering Contradiction:
Improveoverpressure control flexibilityVSAvoidvalve member and control system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies self-service by designing the valve member to be operable by the user directly, without requiring complex external control systems. The valve member can be manually adjusted or controlled through simple mechanisms already present in the device, allowing the system to regulate its own overpressure level without adding significant control complexity.

Inventive Principle:
Principle #25Self-service

3Reliability

If the valve member is closed early during piston movement, then overpressure is reduced for safety, but driving energy is decreased

Engineering Contradiction:
Improvecombustion chamber pressure controlVSAvoiddriving energy
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The patent uses dynamics by making the valve member timing adjustable. The closure timing of the valve member can be dynamically set based on the piston position and required driving energy. This allows optimization of the balance between safety (pressure control) and performance (driving energy) by adjusting when the valve closes during the compression stroke.

Inventive Principle:
Principle #15Dynamics

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 provides a high degree of flexibility in driving energy adjustment, allowing for precise control of overpressure, increased driving efficiency, and wider adaptability, even with conventional uncharged devices.

Implementation Method 1

a driving piston (4) guided therein. The fuel gas is compressed in the course of a resetting of the driving piston (4) to an overpressure

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

A valve member (15) is arranged on the combustion chamber (2) for controlling a release of the compressed fuel gas during an acceleration of the driving piston (4)

Methodology Applied
Scientific EffectPressure relief: Pressure Drop

Implementation Method 3

The combustible gas can be charged to a positive pressure by combined measures by means of a fan and the stroke of the driving piston in order to increase the driving energy

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3349944B1Driving device powered by combustion gas with valve member
Publication Date: 2020.02.19 HILTI AG
  • EP3349944B1 patent drawingFigure 1~2
  • EP3349944B1 patent drawingFigure 3~4
  • EP3349944B1 patent drawingFigure 5~6

AI summary

The invention relates to a driving-in tool, comprising a driving-in piston (4), guided in a cylinder (3), for driving a nail element into a workpiece, and a combustion chamber (2) which is arranged at the driving-in piston (4) and can be filled with an ignitable fuel-gas mixture. A positive pressure of the fuel-gas mixture in the combustion chamber can be produced by a movement of the driving-in piston (4). At least one of the two, the combustion chamber (2) or the cylinder (3), is connected to an external space via a valve member (15), the positive pressure of the fuel-gas mixture produced by the driving-in piston being selectively adjustable by means of the valve member (15).