Drive-in Tool Ram Pre-acceleration Reduces Flywheel Slippage
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Solution Overview
Problem
Existing electrical drive-in tools experience slippage issues when the driving ram contacts the rotating flywheel, leading to energy losses, wear, and limited achievable drive-in energy due to friction, which restricts rotational speeds and increases heating, causing damage to components.
Innovation Solution
An acceleration device is used to pre-accelerate the driving ram before coupling with the flywheel, reducing slippage and energy losses, and allowing for higher rotational speeds by transmitting kinetic energy, enabling the drive-in tool to achieve up to 80 J of drive-in energy through a force accumulator or motorized means, and optionally using an acceleration flywheel with lower circumferential speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the driving ram is directly coupled with the rotating flywheel, then the drive-in energy can be transferred, but slippage occurs causing energy losses and wear
Solution Approach 1:
The driving ram is pre-accelerated by a separate acceleration flywheel before coupling with the drive flywheel. This preliminary acceleration reduces the relative speed difference at coupling, minimizing slippage and energy losses during the transfer of drive-in energy from the drive flywheel to the driving ram.
2Power
If the flywheel rotational speed is increased to achieve higher drive-in energy, then more energy can be delivered, but friction heating increases causing damage and wear
Solution Approach 1:
The acceleration flywheel pre-accelerates the driving ram before it engages with the drive flywheel. This reduces the relative velocity between contacting surfaces during coupling, thereby reducing frictional heating and wear even when the drive flywheel operates at high rotational speeds to deliver greater drive-in energy.
3Loss of energy
If the driving ram is accelerated before coupling, then slippage is reduced, but additional acceleration device complexity is introduced
Solution Approach 1:
An acceleration flywheel is introduced as an intermediary device between the drive flywheel and the driving ram. This separate acceleration mechanism allows the driving ram to be pre-accelerated independently, reducing slippage during coupling with the drive flywheel while maintaining a relatively simple overall device structure through the use of a dedicated acceleration component.
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
The solution significantly reduces slippage and wear, enabling higher rotational speeds and increased drive-in energy transfer, with the driving ram being accelerated to speeds of 0.5 m/s to 20 m/s before coupling, thus overcoming the limitations of existing tools.
Implementation Method 1
the acceleration device has a force accumulator which is preloaded against the driving ram in an initial position of the driving ram and which elastically accelerates the driving ram in the direction of the drive flywheel
Implementation Method 2
the force accumulator is formed as a compression spring element
Data Source
AI summary
A drive-in tool for driving in fastening elements includes a driving ram (13) displaceable in a guide (12) and driven by a drive flywheel (32), a drive unit (30) having an electric motor (31) for rotating the drive flywheel (32), a drive coupling (35) for connecting a coupling section (15) of the driving ram (13) with the at least one drive flywheel (32), and an acceleration device (40) for accelerating the driving ram (13), together with the coupling section (15) in a direction of the drive flywheel (32).