Core Bit Cutting Section for Anti-Jamming Fluid Flow

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Solution Overview

Problem

Drill bits often jam when drilling into reinforced concrete due to iron wedges cut off inside the cutting section, and existing solutions that reduce jamming risk, such as small internal projections, compromise fluid delivery during wet drilling by narrowing the internal gap, hindering effective cooling and rinsing fluid transport.

Innovation Solution

The cutting section is designed with a first open tubular element having a wave-shaped, trapezoidal, or zigzag cross-sectional area and a second closed tubular element with slot-shaped recesses, allowing for improved fluid transport and reducing the risk of jamming by separating force and torque transmission, enabling efficient connection and disconnection of the drill bit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the internal projection of drill segments is reduced to minimize jamming risk, then the jamming risk decreases, but the internal gap becomes narrow which compromises cooling and flushing fluid transport

Engineering Contradiction:
Improvejamming riskVSAvoidfluid transport capacity
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The cutting section is divided into multiple drill segments arranged around the circumference. Each segment is separated from others, creating multiple internal gaps between segments and the drill shaft. This segmentation allows sufficient fluid flow paths while maintaining small internal projections to reduce jamming risk.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The drill segments are nested within the drill shaft, with each segment positioned inside the cylindrical space of the drill shaft. The segments are arranged in a circular pattern, creating annular gaps between the segments and the drill shaft wall, which serve as fluid transport channels.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Quantity of substance

If transport channels are added to improve fluid supply in drill bits with small internal projection, then fluid transport improves, but the device complexity increases

Engineering Contradiction:
Improvefluid transport capacityVSAvoidstructural complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The drill shaft serves multiple functions: it provides structural support, guides the drill segments, and acts as a fluid transport channel through its internal cavity. The internal gap between the drill segments and drill shaft combines both structural and fluid transport functions, eliminating the need for separate transport channels.

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

3Quantity of substance

If the cutting section is replaced with wave-shaped, trapezoidal or zigzag cross-sectional area to improve fluid flow, then fluid transport improves, but manufacturing complexity increases

Engineering Contradiction:
Improvefluid transport capacityVSAvoidmanufacturing effort
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

Instead of making the entire cutting section with complex wave-shaped cross-section, only the drill segments have the complex geometry while the drill shaft maintains a simple cylindrical shape. This partial application of complex geometry achieves fluid flow improvement while keeping manufacturing feasible.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3727775B1Cutting section for a core bit
Publication Date: 2024.05.08 HILTI AG
  • EP3727775B1 patent drawingFigure 1A
  • EP3727775B1 patent drawingFigure 1B
  • EP3727775B1 patent drawingFigure 2A

AI summary

The invention relates to a cutting section (11) which can be connected to a drilling shaft section via a releasable connection device. The cutting section comprises a first open tubular element (14) which is formed in the shape of a first hollow cylinder with a first undulating, trapezoidal, or zigzag-shaped cross-sectional area, a second closed tubular element (15) which is formed in the shape of a second hollow cylinder with a circular cross-sectional area, and one or more drill segments (16) which are connected to the first open tubular element (14) and the second closed tubular element (15).