Star-Shaped Tool Holder Self-Alignment Mechanism
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Solution Overview
Problem
Existing quick-change systems for tool holders require precise angular alignment, either through complex robot designs or cumbersome mechanical movements, leading to increased costs and longer tool change times.
Innovation Solution
A quick-change system that enables automatic angular alignment of the tool holder using star-shaped end faces and balls, allowing self-alignment and secure fixation within a hollow-cylindrical extension, with optional rotatable components for grippers to accommodate less flexible robotic arms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If precise angular alignment is ensured through driver bar and groove or feather key and groove combinations, then the tool holder can be accurately positioned on the holder, but the robot design becomes very precise with high cost or the movement mechanics become significantly more complicated and tool change takes longer
Solution Approach 1:
The tool holder performs self-alignment through its star-shaped end face geometry. When inserted into the holder, the star-shaped face automatically orients itself using the spherical seats and balls, eliminating the need for external alignment mechanisms. This self-aligning capability resolves the contradiction by achieving precise angular positioning without complex robot design or complicated movement mechanics.
Solution Approach 2:
The star-shaped end face of the tool holder is equipped with spherical seats that interact with balls in the holder. This spherical geometry enables smooth rotational movement and automatic alignment during insertion. The curved surfaces allow the tool holder to self-adjust its angular position, achieving precise alignment without complex mechanical guidance systems.
2Manufacturing precision
If the tool holder is first inserted into the assigned recess and then rotated until carrier bar and groove are aligned, then angular alignment can be achieved, but the movement mechanics become significantly more complicated and tool change takes longer
Solution Approach 1:
The tool holder automatically aligns itself during the insertion process through the interaction of its star-shaped end face with the spherical seats and balls. This eliminates the need for a separate rotation step after insertion, as the alignment occurs simultaneously with positioning. The self-aligning mechanism reduces tool change time while maintaining precise angular alignment.
Solution Approach 2:
The spherical seats and balls enable smooth, continuous rotational movement during insertion. The curved geometry allows the tool holder to naturally orient itself to the correct angular position as it is inserted, eliminating the need for discrete rotation steps and reducing overall tool change time.
3Manufacturing precision
If a very precise robot design with low compliance is used to ensure exact angular alignment, then the specified angular position can be met, but the cost of the robot increases
Solution Approach 1:
The alignment function is transferred from the robot to the tool holder itself. The star-shaped end face with spherical seats performs the self-alignment operation, allowing the robot to use simpler, more compliant designs. This resolves the contradiction by achieving precise angular positioning without requiring expensive, highly precise robot designs.
Solution Approach 2:
The spherical seats and balls act as an intermediary mechanism between the robot gripper and the tool holder. This intermediary enables the tool holder to self-align while being held by a less precise robot, transferring the alignment function from the robot to the mechanical interface between holder and tool.
Data Source
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AI summary
A quick-change system for a tool holder (14) is described, comprising a machine-side holder (12) having a hollow cylindrical extension (28) on which a switching sleeve (18) is slidably held, wherein first balls and axially and angularly offset second balls (44) are held in the extension, wherein the tool holder (14) has on the side facing the holder (12) a cylindrical retaining section (22) with longitudinal grooves which cooperate with the first balls to fix the tool holder (14) in a rotationally fixed manner, with a star-shaped end face (40) at the end of the cylindrical retaining section (22) with first recesses (52) between each adjacent apexes of the end face (40) for receiving and guiding the first balls into the longitudinal grooves when inserted into the hollow cylindrical extension (28) and with second recesses (46) on the cylindrical retaining section (22) which cooperate with the second balls (44).to fix the tool holder (14) in the axial direction, wherein recesses (26) associated with the second balls (44) are provided on the switching sleeve (18), which allow radial deflection outwards when these are aligned with the second balls (44), and wherein the tips of the star-shaped end face (40) are designed for angular alignment of the tool holder (14) with the first balls when the holding section is inserted into the hollow cylindrical extension (28).