Reverse-Thread Drill Pilot Fastener for Debris-Evacuating Composite Fixing

Solution Overview

Problem

Existing fastener designs struggle to efficiently secure composite materials to metal frames without causing debris accumulation during installation.

Innovation Solution

A fastener design featuring a pilot section with a cutting tip and drill section, followed by a threaded section with matching twist, and a reverse thread section that evacuates debris while securing to metal frames, allowing self-boring and debris removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a conventional fastener design is used to secure composite materials to metal frames, then the fastening function is achieved, but debris accumulates during installation reducing efficiency

Engineering Contradiction:

Improveinstallation efficiencyVSAvoiddebris accumulation

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The shank is divided into distinct functional sections: a pilot section with cutting tip and drill flutes for debris evacuation, a first threaded section for engagement, and a reverse thread section for debris removal. This segmentation allows each section to perform its specific function optimally, with the pilot section flutes channeling debris away and the reverse thread section actively evacuating material during installation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The reverse thread section acts as an intermediary mechanism between the drilling action and the final fastening. It provides a transition zone that evacuates debris generated during pilot hole creation before the main threaded section engages the material, preventing debris accumulation that would otherwise interfere with proper fastening.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If a self-drilling fastener design is used, then pre-drilling is eliminated, but debris evacuation becomes problematic

Engineering Contradiction:

Improveelimination of pre-drillingVSAvoiddebris evacuation difficulty

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The fastener combines multiple functions in segmented sections along the shank length. The pilot section with its cutting tip and drill flutes handles the self-drilling function, while the reverse thread section specifically addresses debris evacuation. This segmentation allows the fastener to perform self-drilling without requiring separate pre-drilling operations while simultaneously managing debris removal.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The reverse thread section converts the harmful effect of debris generation during self-drilling into a beneficial evacuation mechanism. By incorporating reverse threads that rotate in the opposite direction of the main threading, the design uses the rotational motion to actively pull debris out of the pilot hole, transforming the debris problem into part of the fastening process.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Device complexity

If a standard threaded fastener is used, then simple design is maintained, but counter-sinking capability is insufficient

Engineering Contradiction:

Improvefastener design simplicityVSAvoidcounter-sinking performance

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The shank is divided into distinct functional sections: a pilot section with cutting tip and drill flutes for debris evacuation, a first threaded section for engagement, and a reverse thread section for debris removal. This segmentation allows each section to perform its specific function optimally, with the pilot section flutes channeling debris away and the reverse thread section actively evacuating material during installation.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP2875243B1Fastener with drill pilot and reversed threaded regions

Publication Date: 2026.04.22 SIMPSON STRONG TIE

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AI summary

A fastener includes a shank (100) having a pilot section (110) and a threaded section (113). The pilot section includes a cutting tip (111) and a drill section (112); the threaded section includes a first thread region (113) having the same twist as the drill section and a reverse thread region (114). A helical ridge (115) may be provided in the reverse thread region. A head (104) at the second end includes a top portion such as a disk and an undercut region.