Friction Clamping Tool Holder for Twist-Proof Form Drill

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Solution Overview

Problem

Conventional tool holders for form drills are unsuitable for micro-machining due to uneven force distribution and material inefficiency, and existing solutions like solid carbide form drills are expensive and limited in twist-proofness.

Innovation Solution

A tool holder system featuring a blank with angular cross-sections for the form drill, a circular-cylindrical chuck with a non-conical design, and a union nut with differing pitch angles to ensure secure clamping and prevent twisting, along with a chip stopper for chip containment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a screw connection is used to attach the cutting insert to the basic holder, then the attachment is detachable and material-efficient, but the screw is heavily loaded at certain points due to leverage from rotating movement, causing rapid wear and potential damage

Engineering Contradiction:

Improvedetachable attachmentVSAvoidconnection durability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the screw connection system with a friction-based clamping system using a clamping element that exerts radial clamping force on the insert. This substitution eliminates the leverage problem and uneven force distribution inherent in screw connections, providing more reliable and evenly distributed fastening while maintaining detachability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of connection mechanism from threaded mechanical engagement to friction-based radial clamping. This parameter change allows the connection to better withstand rotating movements without creating leverage moments, thereby improving connection durability while preserving ease of attachment and detachment.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If a basic holder with superstructure or substructure is used to accommodate screw threads, then screw connection is possible, but this solution is unsuitable for micro-processing due to space requirements

Engineering Contradiction:

Improvescrew connection capabilityVSAvoidholder size

Core Design Contradiction:

Ease of manufactureVSVolume of moving object

Solution Approach 1:

The patent replaces the screw thread system with a friction-based radial clamping mechanism. This substitution eliminates the need for superstructures or substructures to accommodate screw threads, allowing the basic holder to maintain a compact, simple cylindrical geometry suitable for micro-processing applications while still providing secure insert attachment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If solid carbide round rod form drills are used, then the solution is stable and inherently wear-resistant, but it is less twist-proof and very expensive due to high material consumption

Engineering Contradiction:

Improvewear resistanceVSAvoidmaterial consumption

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent segments the form drill into two distinct parts: a basic holder made of inexpensive steel and a cutting insert made of hard metal. This segmentation allows the valuable hard metal material to be used only where cutting edges are needed, dramatically reducing material consumption compared to solid carbide drills while maintaining wear resistance at the cutting interface.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a composite tool system combining steel (basic holder) and hard metal (cutting insert). This composite approach optimizes material usage by placing each material where it is most needed: steel for structural support and hard metal for wear-resistant cutting surfaces, thereby reducing overall material consumption while maintaining reliability.

Inventive Principle:

Principle #40Composite materials

4Loss of substance

If cutting inserts or indexable inserts are used with basic holder, then material-efficient and durable, but tool change is time-consuming

Engineering Contradiction:

Improvematerial efficiencyVSAvoidtool change time

Core Design Contradiction:

Loss of substanceVSLoss of time

Solution Approach 1:

The patent replaces the screw connection system with a friction-based radial clamping mechanism. This substitution significantly reduces tool change time by eliminating the need to thread and tighten screws, allowing for rapid insertion and removal of cutting inserts through simple radial clamping and release actions, while maintaining material efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3170595B1Tool holder

Publication Date: 2018.08.29 SIMTEK AG

Figure 1~2b
Figure 3a~3b
Figure 4

AI summary

A blank for a form drill has a first region and a second region, each with a substantially rectangular cross-section. The form drill (2) has a drilling section (21) and a clamping section (22). The clamping section has a first clamping region (221) and a second clamping region (222), each with a substantially rectangular cross-section. The first clamping region is arranged parallel to the second clamping region. The longest side of the cross-section of the first clamping region contacts the longest side of the cross-section of the second clamping region. A tool holder for the form drill comprises a base body, a circular cylindrical chuck, the chuck containing a tool holding region with a non-circular cross-section, and a cap nut.