Rotary Cutting Tool Head Change via Threaded Sleeve

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Solution Overview

Problem

Existing rotationally drivable cutting tools, such as ball milling cutters, require tool head changes to be made when uncoupled from machine tool spindles, increasing complexity and part count, and compromising rigidity and concentricity.

Innovation Solution

A rotationally drivable cutting tool design featuring a threaded sleeve non-rotatably arranged in the holder, with a differential threaded spindle for axial bracing of the cutting head, allowing tool head changes while coupled to the machine tool spindle, utilizing a viscoplastic material for thread production and ensuring thread strength, and incorporating axial support and conical surface contacts for high concentricity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a threaded sleeve is used to connect the cutting head to the holder, then the cutting head can be changed when uncoupled from the spindle, but the tool requires more parts and increased assembly complexity

Engineering Contradiction:
Improvecutting head changeabilityVSAvoidnumber of parts
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent integrates the threaded sleeve directly into the holder as a single monolithic component, eliminating the need for separate threaded sleeve parts. The cutting head is directly threaded into the holder itself, merging the connection function into the holder structure and reducing overall part count while maintaining the ability to change cutting heads.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The holder is designed with universal threading that can accommodate different cutting head types. The threaded structure in the holder serves multiple functions: mechanical connection, axial positioning, and rotational coupling, allowing the same holder to work with various cutting heads without requiring additional intermediate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If an intermediate piece is used to connect the cutting head to the holder, then connection is possible, but rigidity and concentricity are compromised

Engineering Contradiction:
Improveconnection capabilityVSAvoidconcentricity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The intermediate piece is eliminated by merging the connection function directly into the holder. The cutting head is threaded directly into the holder, creating a direct metal-to-metal connection that ensures high concentricity and rigidity. This eliminates the cumulative errors and potential misalignment that would occur with separate intermediate components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts and removes the intermediate piece from the tool assembly, leaving only the essential components (holder and cutting head). This extraction eliminates the source of concentricity errors and rigidity reduction while maintaining the necessary connection capability through direct threading.

Inventive Principle:
Principle #2Taking out (Extraction)

3Volume of moving object

If the threaded sleeve is accessible only through the HSK shank, then the structure is compact, but tool head changes require uncoupling from the spindle

Engineering Contradiction:
Improvetool holder compactnessVSAvoidtool head change accessibility
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

Instead of accessing the threaded sleeve through the HSK shank from the inside, the patent inverts the approach by providing access to the cutting head from the outside end of the holder. The cutting head can be unscrewed and removed from the external end, allowing tool head changes without uncoupling from the spindle while maintaining compactness.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The tool design segments the cutting head as a separate, independently removable component from the holder. This segmentation allows the cutting head to be accessed and changed from the external end without affecting the HSK shank or requiring uncoupling from the spindle, maintaining both compactness and operational ease.

Inventive Principle:
Principle #1Segmentation

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

Enables straightforward tool head changes during operation, maintaining high tool rigidity and concentricity, and reducing the number of parts and production complexities.

Implementation Method 1

a threaded spindle screwed into the threaded sleeve, the threaded spindle having a differential thread with thread sections acting in opposite directions

Methodology Applied
Scientific EffectDifferential thread mechanism: Screw

Implementation Method 2

utilizing a viscoplastic material for thread production and ensuring thread strength

Methodology Applied
Scientific EffectViscoplastic deformation: Plasticity

Implementation Method 3

incorporating axial support and conical surface contacts for high concentricity

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2897751B1Machining tool which is drivable in rotation
Publication Date: 2020.04.01 GUEHRING KG
  • EP2897751B1 patent drawingFigure 1a~1c
  • EP2897751B1 patent drawingFigure 2a~2b
  • EP2897751B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a machining tool (1) which is drivable in rotation, having a holder (10) that extends along a rotation axis (2) and a cutting head (20) that is held coaxially on the holder (10) by screw connection with a threaded sleeve (13) arranged in the holder (10). According to the invention, the threaded sleeve (13) is arranged in the holder (10) so as to rotate therewith and is supported axially at least in the direction of the cutting head (20), and the cutting head (20) is clamped axially with respect to the holder (10) by means of a threaded spindle (30) screwed into the threaded sleeve (13).