Shrink-Fit Chuck Pull-Out Locking for Axial Tool Stability
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Solution Overview
Problem
Tool holders with chucks for rotary tools experience axial migration during operation due to vibrations, leading to precision and dimensional accuracy issues, and potential safety hazards such as the tool leaving the chuck.
Innovation Solution
A tool holder with a pull-out protection system featuring spherical locking elements and grooves that engage in a form-fitting manner, preventing axial migration by creating a torque-proof and axial lock, which can only be released by rotating the tool against its working direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a shrink fit chuck is used to hold the rotary tool, then the tool can be clamped torque-resistently, but axial displacement occurs during operation due to vibrations
Solution Approach 1:
The holding function is divided into two independent mechanisms: the shrink fit chuck provides torque resistance through thermal contraction, while separate locking elements (balls or pins) with locking grooves provide axial position stability. This segmentation allows each mechanism to optimize its specific function without interfering with the other.
Solution Approach 2:
The solution combines two different holding mechanisms in one tool holder system: the shrink fit mechanism (using thermal contraction of the chuck material) and the mechanical locking mechanism (using locking elements and grooves). This composite approach integrates both torque resistance and axial positioning capabilities in a single system.
2Ease of operation
If the inner diameter of the shrink-fit chuck is enlarged to insert the tool, then the tool can be loaded quickly, but the tool may become loose after cooling
Solution Approach 1:
The locking elements and locking grooves are pre-positioned in the tool holder and tool shank respectively, so that when the tool is inserted into the enlarged chuck, the locking mechanism is already in place to engage automatically as the chuck cools and contracts, ensuring both easy insertion and reliable holding.
3Stability of the object's composition
If locking elements are added to prevent axial migration, then axial stability is improved, but the device complexity increases
Solution Approach 1:
The locking function is segmented into simple, discrete elements (balls or pins) that can be individually positioned in bearing bores, rather than using a complex continuous locking mechanism. This segmentation simplifies the overall structure while achieving the axial stability function.
Solution Approach 2:
Spherical locking elements (balls) are used instead of complex geometric locking mechanisms. The spherical shape allows for simple engagement with corresponding grooves in the tool shank, providing axial locking with minimal structural complexity and smooth operation.
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 ensures precise machining and maintains dimensional accuracy, reducing waste and eliminating safety risks by securely holding the rotary tool in place during operation.
Implementation Method 1
The coil arrangement is connected to a high-frequency alternating current generator and induces eddy currents in the metallic sleeve section, which heat the sleeve section
Implementation Method 2
the sleeve section heats up quickly so that it expands thermally and the inside diameter of the receiving opening is increased
Implementation Method 3
Due to the rapid cooling that now begins, the shrink fit chuck shrinks back to its original size, whereby the cylindrical shank is torque-tightly connected with its peripheral surface to the inner peripheral surface of the receiving opening of the shrink fit chuck
Implementation Method 4
The pull-out protection device comprises at least one locking element and at least one locking groove corresponding thereto and receiving the locking element, which cooperate in a form-fitting manner
Data Source
Figure 1
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AI summary
The invention relates to tool holders with a tool holder, in particular chucks such as shrink fit chucks, collet chucks, hydraulic expansion chucks and HG chucks, and the shank of a tool received therein, in particular a rotary tool, wherein the tool holder includes a pull-out safeguard that blocks axial migration of the tool. This pull-out protection unit comprises at least one blocking element and at least one blocking groove corresponding thereto and receiving the blocking element, which interact in a form-fitting manner. Both the locking element and the locking groove are designed at least partially like a spherical head. Preferably, the tool has the locking groove. Due to preferably spirally arranged locking grooves along the cylindrical shank of rotary tools, the pitch directions of which correspond to the groove direction of the tool, the tool is axially locked so that the tool cannot axially migrate out of the tool holder during operation. In addition, force-exerting elements are arranged, which create a play-free fit of the tool after it has been shrunk onto the pull-out protection.