Ring Drill Bit Inner Profile for Easier Core Removal

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Solution Overview

Problem

Ring drill bits face issues with drill core jamming due to fragments breaking off during drilling, which can cause mechanical instability and complicate the removal of jammed cores.

Innovation Solution

The ring drill bit design features a ring segment with varying inner distances along its circumference, creating gaps between the ring segment and the drill core, reducing friction and the risk of jamming, and allowing for easier removal of jammed cores by varying the inner surface profile to minimize contact and maximize gap formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the ring segment has a constant inner distance from the longitudinal axis, then the mechanical stability during drilling is improved, but the drill core jams in the interior due to increased friction and contact surface

Engineering Contradiction:

Improvemechanical stabilityVSAvoiddrill core removal

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The ring segment's inner lateral surface is designed with locally varying inner distances from the longitudinal axis, creating alternating regions of smaller and larger clearances. This local variation reduces the overall contact surface and friction between the ring segment and drill core, facilitating easier core removal while maintaining adequate mechanical stability through the distributed support structure

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The inner lateral surface is effectively segmented into multiple zones with different inner distances, creating a pattern of contact and non-contact regions along the circumference. This segmentation allows the drill core to be supported at multiple points while maintaining gaps that prevent jamming and facilitate removal

Inventive Principle:

Principle #1Segmentation

2Strength

If the contact surface between ring segment and drill core is increased, then the mechanical stability is improved, but the friction increases causing drill core jamming

Engineering Contradiction:

Improvemechanical stabilityVSAvoidfriction and jamming

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The design implements local quality variation by creating specific regions with smaller inner distances for support and regions with larger inner distances for reduced friction. This selective distribution of contact zones maintains necessary mechanical strength while minimizing harmful friction effects that lead to jamming

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The design converts the potentially harmful continuous contact into a beneficial intermittent contact pattern. The varying inner distances create deliberate gaps that transform the harmful friction effect into a beneficial mechanism for preventing jamming, while the distributed support zones maintain structural integrity

Inventive Principle:

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

Data Source

PatentUS20240399472A1Ring drill bit with improved drill core removal

Publication Date: 2024.12.05 HILTI AG

AI summary

Ring drill bit including a drilling shaft and a ring segment (22) which is fastened by an underside to an end face of the drilling shaft and which has an inner lateral surface (26). The inner lateral surface (26) has an inner distance (B(φ, h)) from the longitudinal axis (23) perpendicular to the longitudinal axis (23) of the drilling shaft. The inner distance (B(φ, h)) varies in the plane perpendicular to the longitudinal axis (23) and has a first minimum value (Bmin,1), a first maximum value (Bmax,1), a second minimum value (Bmin,2) and a second maximum value (Bmax,2).