Removable Tool Head External Clamping Dovetail Connection

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Solution Overview

Problem

Existing cutting tool assemblies require a through hole in the tool head for clamping, which limits design flexibility and space, especially for tool heads with small dimensions, and can lead to increased risk of breakage under operational forces.

Innovation Solution

A cutting tool assembly with a removable tool head that uses an external clamping mechanism, featuring a dovetail connection between the tool head and holder, eliminating the need for a through hole and enhancing resilience against operational forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a through hole is used for clamping the tool head to the holder, then the clamping function is achieved, but the tool head structure becomes more complex and the risk of breakage increases

Engineering Contradiction:
Improverisk of breakageVSAvoidtool head structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the through hole from the tool head structure entirely. Instead of passing the clamping screw through the tool head, the screw engages with a threaded bore formed only in the holder body. This extraction of the through hole eliminates the structural weakness while maintaining the clamping function through the external engagement between the screw head and the tool head's external surface.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent inverts the traditional clamping approach by reversing which component contains the threaded feature. Conventionally, the tool head has a threaded hole for the screw; in this invention, the holder has the threaded bore and the tool head engages externally. This inversion allows the tool head to be clamped without requiring a through hole, thereby reducing structural complexity and breakage risk.

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

2Adaptability or versatility

If a through hole is provided in the tool head for clamping, then the attachment mechanism is simplified, but design flexibility and space utilization are limited

Engineering Contradiction:
Improvedesign flexibilityVSAvoidclamping mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

By removing the through hole from the tool head, the patent frees up internal space and eliminates design constraints associated with hole placement, sizing, and reinforcement. This allows for greater design flexibility in the tool head geometry and enables better space utilization for other functional features while the clamping mechanism remains straightforward through external screw engagement.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If a through hole is used for clamping, then the attachment element can be easily installed, but the tool head requires additional material and structural reinforcement

Engineering Contradiction:
Improvetool head fabricationVSAvoidmaterial usage
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The patent eliminates the need to machine a through hole through the entire tool head, which removes the associated manufacturing steps of drilling, tapping, and reinforcing the hole structure. The tool head can be manufactured as a solid or near-solid component without through-hole features, simplifying the fabrication process and reducing material removal while the threaded bore in the holder provides the necessary threading functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2838684B1Cutting tool assembly with removable tool head
Publication Date: 2019.02.06 ISCAR LTD
  • EP2838684B1 patent drawingFigure 1~2
  • EP2838684B1 patent drawingFigure 3~5
  • EP2838684B1 patent drawingFigure 6~8

AI summary

A cutting tool assembly (100, 200, 300) has a tool holder (102, 202, 302), a tool head (104, 204, 304) and a tool head fastening member. The tool holder has a holder mating surface (114, 314) and a holder clamping portion (112) spaced apart in the rearward direction from the holder mating surface (114, 314). The tool head (104, 204, 304) is provided with a tool head mating surface (132, 316) and a tool head clamping recess (124). In an assembled position of the cutting tool assembly (100, 200, 300) the tool head mating surface (132, 316) forms a dovetail connection with the holder mating surface (114,314) and the tool head fastening member (106) clamps the tool head clamping recess (124), thereby externally clamping the tool head (104, 204, 304) to the tool holder (102, 202,302).