Movable Slide Combustion Chamber for Variable Driving Energy
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Solution Overview
Problem
Existing hand-held tackers with propellant charges face challenges in optimizing the burning of pyrotechnic charges, leading to inefficient energy transmission and residue issues due to the combustion of powder grains and fibers, which affects the reproducibility and residue-free operation.
Innovation Solution
The design incorporates a movable slide in the combustion chamber that adjusts to minimize additional volume, allowing for precise control of driving energy by varying the blow-off duct cross-section and ejection area, ensuring efficient combustion and energy transfer to the fastener.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a valve-like slide is adjusted perpendicular to the driving-in axis to create dead space volume, then driving energy can be adjusted, but additional volume caused by the actuator reduces the control range and maximum driving energy
Solution Approach 1:
The slide is made movable along the central axis to dynamically adjust the dead space volume. By moving the slide between different positions, the combustion chamber volume can be varied to control driving energy, while minimizing the space occupied by the actuator itself through axial movement rather than perpendicular adjustment.
Solution Approach 2:
The adjustment mechanism is reoriented from perpendicular to the driving-in axis (conventional approach) to parallel with the central axis (new approach). This dimensional change allows the slide to adjust volume along the same axis as combustion, minimizing additional volume while maintaining full control range for driving energy adjustment.
2Adaptability or versatility
If the slide is moved perpendicular to the driving-in axis to adjust dead space, then driving energy control is achieved, but friction and material abrasion increase due to contact between slide and piston member
Solution Approach 1:
The harmful contact between the slide and piston member is eliminated by extracting the source of friction. The slide is designed to move along the central axis without contacting the piston member, removing the friction and abrasion problem while preserving the driving energy adjustment function through volume control.
Solution Approach 2:
The central axis serves as an intermediary path for the slide movement, allowing volume adjustment without direct contact between moving parts. By routing the adjustment mechanism through the central axis rather than perpendicular to it, the design avoids friction between the slide and piston member while maintaining control capability.
3Use of energy by moving object
If multiple propellant charges are used to achieve different driving energies, then energy range is sufficient, but device complexity and operation complexity increase
Solution Approach 1:
A single propellant charge design is made universal by combining it with an adjustable dead space volume mechanism. The slide allows one propellant charge to deliver multiple driving energy levels by varying the combustion chamber volume, eliminating the need for multiple specialized propellant charges and simplifying both device and operational complexity.
Solution Approach 2:
Instead of changing the propellant charge itself, the driving energy is adjusted by changing the physical parameter of the combustion chamber volume through slide movement. This parameter change approach allows a single propellant charge to produce variable driving energies, reducing the number of propellant types needed while maintaining a wide energy range.
4Temperature
If powder grains are initially driven in front of the flame front, then combustion occurs, but residue is generated and burning reproducibility decreases
Solution Approach 1:
The slide position is pre-adjusted to optimize the dead space volume before ignition occurs. This preliminary action ensures that powder grains are properly positioned and the combustion chamber is optimally configured, leading to more reproducible and complete burning with reduced residue generation.
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 enables a wide range of driving energies to be achieved with a single propellant charge, reducing residue and improving the efficiency and reproducibility of the fastening process, allowing for universal use without the need for multiple propellant charges.
Implementation Method 1
a piston member (2) in a hand-held tool (1) subjected to kinetic energy by expansion of the combustion gases of a pyrotechnic charge
Implementation Method 2
expansion of the combustion gases of a pyrotechnic charge
Data Source
Figure 1~2
Figure 3~4
Figure 4a~5
AI summary
Disclosed is a driving-in device comprising a hand-held housing in which a piston member is accommodated to transmit energy to a fastening element to be driven in, an especially replaceable propellant charge, and a combustion chamber which is located between the propellant charge and the piston member and which extends in particular around a central axis (A), and a control element which allows the energy transmitted from the propellant charge to the piston member to be variably modified. Said driving-in device is characterized in that a movable sliding element of the control element forms a section of a sidewall of the combustion chamber, said section adjoining the piston member.