Impact Mechanism Idle-Strike Damper Arrangement
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Solution Overview
Problem
Hammer drills and chipping hammers face issues with idle strikes when the pressing force is low, leading to full impact energy being absorbed by the hammer and tool fitting, causing excessive force peaks and vibration, which can damage downstream components.
Innovation Solution
An additional idle-strike damper element is introduced between the tool fitting and the guide housing, working in conjunction with a rebound-strike damper element to reduce the anvil's return speed and distribute impact energy, allowing the tool fitting to be mounted in a floating manner and attenuate a significant part of the impact energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an idle-strike damper element is used to protect downstream components from force peaks, then the components are protected from excessive forces, but the anvil return speed increases and the hammer deactivation behavior is affected
Solution Approach 1:
The damping function is segmented into two separate damper elements: the first idle-strike damper element (11) acts between the anvil and tool fitting, while the second idle-strike damper element (31) acts between the tool fitting and guide housing. This segmentation allows each damper to handle specific portions of the impact energy, with the second damper specifically targeting the tool fitting to reduce its load without excessively increasing anvil return speed.
2Object-affected harmful factors
If the tool fitting is made floating to reduce load, then impact energy is attenuated, but the structural complexity increases
Solution Approach 1:
The tool fitting (50) is positioned within the guide housing (80) and made movable in the axial direction, creating a nested arrangement where the tool fitting can float within the guide housing. This nesting allows the tool fitting to move independently to absorb impact energy while maintaining a compact overall structure.
Solution Approach 2:
The second idle-strike damper element (31) acts as an intermediary between the tool fitting (50) and the guide housing (80), providing a controlled compliance that allows the tool fitting to move floatingly to attenuate impact energy while preventing excessive movement.
3Object-affected harmful factors
If additional damper elements are added to reduce impact energy, then the load on tool fitting is reduced, but the device complexity increases
Solution Approach 1:
The damping system is segmented into multiple functional zones: the first idle-strike damper element (11) handles the initial impact between anvil and tool fitting, while the second idle-strike damper element (31) handles the subsequent impact between tool fitting and guide housing. This segmentation allows distributed energy absorption across multiple components rather than relying on a single oversized damper.
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 configuration reduces the load on the tool fitting and downstream components by minimizing the anvil's return speed and distributing the impact energy effectively, thereby protecting the components from excessive force peaks and vibrations.
Implementation Method 1
Idle-strike damping by the idle-strike damper element influences the return speed of the anvil after an idle strike... the additional idle-strike damper element that acts between the tool fitting and the guide housing is compressed, and so the anvil is accelerated back only to a comparatively minor extent
Implementation Method 2
rebound-strike damper elements, which are preferably in the form of elastomer damping elements, are used in order to keep force peaks on downstream components and vibrations as low as possible
Data Source
AI summary
Hammer drill and/or chipping hammer (100) having a drive motor (70), an impact mechanism (10) and a tool fitting (50) for fitting a tool (110), wherein the impact mechanism (10) has an anvil (30) that is axially displaceable in an anvil guide (20) and acts on the tool (110), wherein the impact mechanism (10) has an idle-strike damper element (11), which acts between the anvil (30) and the tool fitting (50), and wherein the impact mechanism has a guide housing (80), which engages at least partially around the anvil (30) and/or the tool fitting (50), wherein an additional idle-strike damper element (31) is provided, which acts between the tool fitting (50) and the guide housing (80).