Piezo Piston Holder for Combustion Driving Tool
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Solution Overview
Problem
Conventional driving tools with rapidly expanding gas for high driving energies struggle to securely hold and quickly release the driving piston, leading to inefficiencies in energy transfer and setting energy.
Innovation Solution
Incorporating a piezo actuator in the piston holder allows for precise and rapid release of the driving piston through electrical voltage control, utilizing multiple piezoelectric actuators around the circumference for secure mounting and a gear mechanism to adapt to mechanical and thermal tolerances, enabling delayed release based on pressure, temperature, or time thresholds for optimized energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional holding device is used to secure the driving piston, then the piston can be held against combustion pressure, but the release speed is insufficient for optimal energy transfer
Solution Approach 1:
The patent replaces the conventional electromagnetic coil holding device with a piezoelectric actuator system. The piezoelectric actuator responds almost immediately to electrical voltage signals, enabling ultra-fast piston release. The system uses a locking element with a groove that engages the piston, providing secure mechanical holding when locked, and rapid release when the piezoelectric actuator is activated by voltage.
2Use of energy by moving object
If the driving piston is released immediately after ignition, then the release timing is fast, but the energy transfer efficiency is reduced due to insufficient pressure buildup
Solution Approach 1:
The patent implements a controlled delay mechanism where the piston is held in position for a defined time interval after ignition before release. This allows combustion pressure to build up to optimal levels. The piezoelectric actuator is triggered after this predetermined delay, ensuring the piston releases at the precise moment when pressure and energy transfer efficiency are maximized.
3Adaptability or versatility
If a simple holding mechanism is used, then the device complexity is low, but the ability to adapt to mechanical and thermal tolerances is insufficient
Solution Approach 1:
The patent introduces a locking element as an intermediary component between the piezoelectric actuator and the piston. This locking element features a groove that positively engages with the piston, providing form-fitting connection. The gear mechanism acts as another intermediary, translating the small displacement of the piezoelectric actuator into the larger movement required to engage or disengage the locking element, thereby accommodating mechanical tolerances.
4Speed
If the piezoelectric actuator stroke is small, then the actuator response is fast and precise, but the mechanical movement required for piston release is insufficient
Solution Approach 1:
The patent employs a gear mechanism that converts the small linear displacement of the piezoelectric actuator into a larger rotational or leveraged movement. The gear amplifies the actuator's stroke through mechanical advantage, enabling the locking element to move sufficient distances to engage or release the piston despite the piezoelectric actuator's inherently small displacement.
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 high-speed and temporally accurate release of the driving piston, increasing achievable setting energy and allowing for adjustable energy delivery, optimizing the driving-in process with enhanced energy transfer and reduced mechanical contamination from combustion products.
Implementation Method 1
The piston holder (10) comprises at least one piezoelectric actuator (21), in particular two or more piezoelectric actuators (21), distributed around the circumference of the cylinder (3)
Implementation Method 2
Provision is made for the piezoelectric actuator to be supported against the force of a prestressing spring
Implementation Method 3
c. igniting a combustion process in a combustion chamber (2) with increasing pressure acting on the driving piston (4)
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a driver device, comprising a driving piston for driving a nail element into a workpiece, which driving piston is guided in a cylinder, and comprising a combustion chamber arranged adjoining the driving piston. In the course of a driving process, a pressure increase occurs in the combustion chamber as a result of a combustion process. Before the driving process, the driving piston is held in an initial position by means of a piston holder. The piston holder comprises a piezoelectric actuator.