Tool Holder Locking Mechanism for Machining Center Spindle Protection

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Solution Overview

Problem

Machining centers with nonrotational tools face issues where improper spindle operation or large cutting loads can lead to premature spindle bearing damage and reduced spindle life, as existing solutions do not adequately address the need for secure tool fixation without compromising spindle integrity.

Innovation Solution

A tool holder design featuring a sleeve fitted to the spindle, a drive shaft connected to the sleeve, a rotatable tool holder body, and a locking mechanism with a positioning pin that allows or prevents rotation based on the pin's insertion, ensuring the tool holder's stability and preventing spindle damage during improper operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a nonrotational tool is mounted on a spindle of a machining center, then the tool can perform turning operations, but the spindle bearings may be damaged due to improper operation or large cutting loads

Engineering Contradiction:

Improvetool functionalityVSAvoidspindle bearing life

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The tool holder employs a dynamic locking mechanism that transitions between locked and unlocked states. The locking pin engages with positioning holes to prevent rotation during cutting operations, then disengages to allow rotation during tool changes. This dynamic state change enables the system to adapt between different operational requirements while protecting the spindle.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The locking pin acts as an intermediary element between the tool holder and spindle. It transfers and absorbs the cutting loads and operational stresses, preventing these forces from being directly transmitted to the spindle bearings. The pin serves as a protective mediator that safeguards the spindle while enabling tool functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the tool holder is fixed without turning to prevent tool rotation, then the nonrotational tool is securely held, but the spindle may be damaged during improper operations

Engineering Contradiction:

Improvetool holder stabilityVSAvoidspindle damage risk

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The locking mechanism applies preliminary anti-action by engaging the locking pin in positioning holes before cutting operations begin. This pre-engagement prevents tool rotation and stabilizes the tool holder, while simultaneously preparing the locking mechanism to absorb any abnormal forces that may arise during operation, protecting the spindle from damage.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The locking pin and positioning holes structure provides beforehand cushioning by being designed to absorb and accommodate abnormal forces and improper operations. The mechanical engagement creates a buffer zone that protects the spindle bearings from sudden loads or misoperations, allowing the system to withstand unexpected stresses without damaging the spindle.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If a locking mechanism is added to prevent tool rotation, then the tool can be securely fixed, but the device complexity increases

Engineering Contradiction:

Improvetool fixation securityVSAvoidtool holder structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The locking mechanism is segmented into distinct functional components: the locking pin, positioning holes, and spring element. Each component has a specific function - the pin provides locking, the holes provide positioning, and the spring provides return force. This segmentation allows for simple manufacturing and assembly while achieving reliable tool fixation without excessive complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The locking mechanism is designed to be self-actuating through spring force. When the tool holder is rotated into position, the spring automatically pushes the locking pin into the positioning hole, securing the tool without requiring additional actuators or complex control systems. The mechanism serves itself, reducing overall device complexity while maintaining reliable fixation.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS9364899B2Tool holder on which nonrotational tool of machining center is mounted

Publication Date: 2016.06.14 FANUC LTD

AI summary

A tool holder on which a nonrotational tool is mounted is mounted on a spindle of a machining center. A tool holder body of the tool holder includes a positioning pin that is inserted into the machining center and a locking mechanism. When the positioning pin is not inserted into the machining center, the locking mechanism locks the rotation of the tool holder body relative to a drive shaft. When the positioning pin is inserted into the machining center, the locking mechanism allows the rotation of the tool holder body relative to the drive shaft.