Dual-Locking Tool Holder for Percussive Power Tools
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Solution Overview
Problem
Existing tool holders for percussively operated power tools experience accelerated wear and vibration in the locking device due to increasing hammering power, leading to inefficient load distribution and reduced service life.
Innovation Solution
A tool holder with a dual locking element system, featuring a restoring element with an elastic component and a contact shoulder, which generates unequal deflection chambers for the locking elements, reducing the force required for tool insertion and enhancing the locking mechanism's durability by distributing loads symmetrically and damping vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the hammering power of power tools is increased, then the locking element is subjected to heavier loads, but this causes accelerated wear to components of the locking device
Solution Approach 1:
The locking device is divided into two separate locking elements (first locking element and second locking element) that operate independently. Each locking element handles a portion of the total load, distributing the stress from increased hammering power across multiple components rather than concentrating it on a single locking element, thereby reducing wear on each individual component.
Solution Approach 2:
The deflection chambers for the two locking elements are designed with different sizes (first deflection chamber larger than the second). This asymmetric design creates different restoring forces on each locking element, optimizing the load distribution and wear characteristics for each specific component based on its local requirements.
2Force
If the locking action is strengthened to secure the tool insert, then the locking force increases, but this requires increased force from the user when changing tool inserts
Solution Approach 1:
The locking elements are designed to be dynamically responsive, moving radially into and out of the detent indentations based on the operational state. During normal operation, both locking elements engage strongly to provide secure locking. During tool insert changes, the asymmetric deflection chambers allow one locking element to disengage more easily than the other, reducing the force required by the user while maintaining strong locking during operation.
Solution Approach 2:
The deflection chambers are intentionally designed asymmetrically, with the first deflection chamber having a larger size than the second. This creates unequal restoring forces on the two locking elements, allowing one to engage and disengage more easily than the other. This asymmetry optimizes both the locking force during operation and the ease of tool insert removal.
3Object-affected harmful factors
If the locking device is made vibration-resistant to handle sudden loads, then the load distribution improves, but the device complexity increases
Solution Approach 1:
The deflection chambers are designed to allow the locking elements to move radially during sudden load transitions, cushioning the impact before it reaches the blocking element. This pre-cushioning effect absorbs the shock of sudden loads (such as transitioning from hammering to idling state) and reduces vibration, while maintaining a relatively simple overall device structure.
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 dual locking element system increases the locking force, extends the service life of the tool holder, and simplifies tool changes while reducing wear and vibration-induced damage, ensuring secure tool retention and improved usability.
Implementation Method 1
The restoring element (38) includes an elastic element (42) which, between a reference face (59) and the holding element (40), generates a restoring force (FR)
Implementation Method 2
The elastic element (42) is embodied as an elastic damping element (142b). The elastic damping element (142b) acts in damping fashion on the vibration of the locking device (30, 130) that is induced by the sudden operating loads
Implementation Method 3
The elastic element can be embodied as a spring element (42a)
Data Source
AI summary
The invention relates to a tool holder for an electric tool, particularly for a chisel hammer and/or drill hammer. A tool receptacle is provided for receiving a cylindrical shaft of an insertion tool introduced through an insertion opening. The cylindrical shaft has at least two diametrically opposed detent depressions on its circumferential surface. The tool holder further has a locking device having at least one locking element, at least one blocking element and at least one restoring element. According to the invention, the locking device has at least two locking elements. Upon insertion of the cylindrical shaft of the insertion tool, the restoring element applies different forces to the locking elements of the locking device.