Magnetic Tool-Holder Coupling for Stone Machining

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Solution Overview

Problem

Machines for machining block or slab materials, such as stone, require sophisticated and expensive systems for precise positioning and movement of the spindle to align mechanical coupling elements, leading to slow tool-changing times and increased manufacturing costs.

Innovation Solution

A tool-holder unit with a coupling assembly featuring alternating magnets of opposite polarities at the spindle and tool-holder ends, allowing for automatic self-centering and alignment, eliminating the need for position sensors and inverters, and simplifying the spindle positioning system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a sophisticated positioning system with sensors and inverters is used to align mechanical coupling elements, then manufacturing precision is improved, but device complexity increases and manufacturing cost increases

Engineering Contradiction:
Improvealignment precision of coupling elementsVSAvoidcomplexity of positioning system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces the sophisticated mechanical positioning system (sensors, inverters, precision motors) with a magnetic field-based self-alignment mechanism. Magnets embedded in the coupling elements create magnetic attraction forces that automatically guide and align the tool-holder with the spindle during the coupling process, eliminating the need for complex electronic positioning systems while maintaining alignment precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The coupling elements are designed to self-align through magnetic attraction forces. When the tool-holder approaches the spindle, the magnets in the coupling elements automatically generate attractive forces that guide the alignment of mechanical coupling elements (such as drive pins with housing seats) without requiring external sensors or control systems. The system serves itself by using the magnetic field to achieve the alignment that would otherwise require complex positioning equipment.

Inventive Principle:
Principle #25Self-service

2Manufacturing precision

If a sophisticated positioning system with sensors and inverters is used to align mechanical coupling elements, then manufacturing precision is improved, but manufacturing cost increases

Engineering Contradiction:
Improvealignment precision of coupling elementsVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive electronic positioning components (sensors, inverters, precision motors) with simple embedded magnets in the coupling elements. This substitution dramatically reduces manufacturing costs while maintaining alignment precision, as magnets are inexpensive components compared to the sophisticated electronic positioning system they replace.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses inexpensive magnets as the core alignment mechanism instead of expensive electronic positioning systems. The magnetic coupling elements are simple, cheap components that can be easily manufactured and replaced if needed, providing a cost-effective solution for achieving precise alignment of coupling elements.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Productivity

If automated tool changing is implemented with precise positioning systems, then productivity is improved, but device complexity increases

Engineering Contradiction:
Improvetool-changing speedVSAvoidcomplexity of positioning system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The automated tool-changing system uses self-aligning magnetic coupling elements that automatically guide and secure the tool-holder to the spindle without requiring complex positioning control. The magnetic attraction forces enable rapid, automated coupling and decoupling operations, improving tool-changing speed while keeping the system relatively simple.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces complex electronic positioning and control systems with magnetic field-based self-alignment mechanisms for automated tool changing. This substitution maintains high productivity by enabling rapid automated coupling while significantly reducing device complexity compared to traditional sensor-and-inverter-based positioning systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Manufacturing precision

If mechanical coupling elements require precise alignment through sophisticated positioning, then reliability is reduced due to more components, but manufacturing precision is improved

Engineering Contradiction:
Improvealignment precision of coupling elementsVSAvoidsystem reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The magnetic coupling elements automatically self-align during the coupling process through magnetic attraction forces, eliminating the need for complex positioning systems with multiple components. This self-aligning mechanism reduces the number of components that could fail, thereby improving system reliability while maintaining alignment precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the unreliable electronic positioning system (sensors, inverters, motors) with a simple magnetic field-based alignment mechanism. The magnetic coupling elements have fewer moving parts and electronic components, which inherently improves reliability while achieving the same alignment precision through magnetic attraction forces.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Facilitates quick and precise alignment of tool-holders, reducing tool-changing time, lowering manufacturing costs, and enhancing reliability by eliminating sensor and inverter dependencies, while maintaining mechanical simplicity and efficiency.

Implementation Method 1

at least two first magnets with north polarity and at least two second magnets with south polarity, associated to said front free end of the spindle and circumferentially arranged alternating with each other at said front free end, at least two third magnets with south polarity and at least two fourth magnets with north polarity, associated to a free end of said tool-holder and circumferentially arranged alternating with each other at said free end of the tool-holder

Methodology Applied
Scientific EffectMagnetic attraction: Magnetism

Data Source

PatentEP2731762B1Tool-holder unit of a machine for machining block or slab materials, machine including such unit for machining block or slab materials
Publication Date: 2018.01.24 GMM SPA
  • EP2731762B1 patent drawingFigure 1
  • EP2731762B1 patent drawingFigure 2
  • EP2731762B1 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) is mounted, and a coupling assembly (61) for removably coupling a second machining tool (28) to a front free end (12a) of the spindle (12) comprising a tool-holder (50) associated to the second machining tool (28), at least two first magnets (65) with north polarity and at least two second magnets (66) with south polarity, associated to the front free end (12a) of the spindle (12) and circumferentially arranged alternating with each other at said front free end (12a), at least two third magnets (55) with south polarity and at least two fourth magnets (56) with north polarity, associated to a free end of said tool-holder (50) and circumferentially arranged alternating with each other at said free end of the tool-holder (50), and 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.