Machine Tool-Holder Coupling With Radial Locking Against Detachment

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Solution Overview

Problem

Existing machine tool-holder units for machining block or slab materials, such as stone, face issues with tool detachment due to high transverse stresses during operations like milling, leading to eccentric rotation, vibrations, and potential safety hazards.

Innovation Solution

The tool-holder unit incorporates a second axial locking element that is translationally movable in a radial direction to securely lock the tool-holder onto the spindle, preventing detachment even under high transverse stresses, ensuring active safety and reliable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a magnetic fixing device is used to couple the tool-holder to the spindle, then the tool-holder can be quickly assembled and disassembled, but the tool-holder may detach under high transverse stresses

Engineering Contradiction:
Improveassembly and disassembly speedVSAvoidtool-holder attachment reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The locking mechanism is divided into two independent parts: a magnetic fixing device for quick assembly/disassembly and a second axial locking element for secure positioning. This segmentation allows each component to perform its specialized function - the magnetic device provides ease of operation while the mechanical locking element ensures reliability under stress

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second axial locking element is preliminarily positioned to engage with the spindle before the tool-holder is fully assembled. This preliminary action creates a pre-locking mechanism that prevents detachment even when the magnetic fixing device is later removed or fails under high transverse stresses

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If only a magnetic fixing device is used, then the structure remains simple, but the tool-holder becomes unsafe under high transverse stresses

Engineering Contradiction:
Improvecoupling assembly structureVSAvoidtool detachment hazard
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The second axial locking element serves as a preliminary safety cushion against tool detachment. It is positioned and configured to engage beforehand, creating a backup mechanism that cushions against the harmful effect of tool detachment under high transverse stresses, thereby reducing safety hazards without significantly increasing structural complexity

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 effectively prevents accidental detachment of the tool-holder during machining, maintaining operational stability and safety, even under sudden or increased transverse stresses, thereby ensuring accurate machining and reducing the risk of machinery and material damage.

Implementation Method 1

a magnetic coupling device provided with elements cooperating in abutment relationship to make the tool-holder and the spindle rotationally integral with each other

Methodology Applied
Scientific EffectMagnetic coupling: Magnetism

Implementation Method 2

at least a second axial locking element of the tool-holder, configured to removably lock in translation and in a substantially axial direction the tool-holder in the spindle

Methodology Applied
Scientific EffectMechanical locking: Mechanical Force

Data Source

PatentEP3887090B1Tool-holder unit of a machine for machining block or slab materials, machine including such unit and method for machining block or slab materials
Publication Date: 2022.05.18 GMM SPA
  • EP3887090B1 patent drawingFigure 1
  • EP3887090B1 patent drawingFigure 2
  • EP3887090B1 patent drawingFigure 3

AI summary

The invention relates to a tool-holder unit (10) of a machine (100) for machining block or slab materials (200), the tool-holder unit (10) being moveable above a working plane (102) of said machine (100) on which the block or slab material (200) to be machined is laid, wherein the tool-holder unit (10) comprises: a spindle (12) on which a circular blade (11) can be mounted, and a coupling assembly (61) for removably coupling a second machining tool (28, 128) to a front free end (12a) of the spindle (12), comprising: a) a tool-holder (50) associated to the second machining tool (28, 128); b) at least one mechanical coupling device (63) provided with elements cooperating in abutment relationship (58, 68) to make the tool-holder (50) and the spindle (12) rotationally integral with each other; and c) a first axial locking element of the tool-holder (50) of the magnetic type, configured to removably lock in translation and in a substantially axial direction said tool-holder (50) on the spindle (12), d) a substantially cylindrical shank (57a) extending from said free end of the tool-holder (50); e) a substantially cylindrical housing seat (67a) of said shank (57a), axially positioned in said spindle (12) or, if present, in a tool-holder coupling element (60) associated to the front free end (12a) of the spindle (12); and f) at least a second axial locking element (70) of the tool-holder (50), configured to removably lock in translation and in a substantially axial direction the tool-holder (50) in the spindle (12), the axial locking element (70) being translationally movable in the radial direction to removably lock the shank (57a) in the respective housing seat (67a).