Core Bit Cutting Section Structure for Jam Relief and 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 either increase the risk of jamming or complicate manufacturing, while also limiting the flow of cooling and rinsing fluids during wet drilling.

Innovation Solution

The cutting section is designed with a first hollow cylinder having a wave-shaped, trapezoidal, or zigzag cross-sectional area, separated into two tubular elements for improved force and torque transmission, allowing for a wider internal gap for fluid flow and easier jam release, manufactured from profiled sheets using cold or hot forming processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the internal projection of drill segments is reduced to prevent jamming, then the risk of cutting section jamming in reinforced concrete is reduced, but the internal gap becomes narrow which limits cooling and flushing fluid flow

Engineering Contradiction:
Improverisk of jammingVSAvoidfluid flow
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The cutting section is divided into two separate tubular elements (first closed tubular element and second closed tubular element) that can be connected detachably. This segmentation allows the internal gap to be maintained or increased while still preventing jamming, as the modular structure provides flexibility in designing the internal flow path without compromising the external dimensions that prevent substrate engagement

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The detachable connection between the first and second closed tubular elements creates a dynamic structure that can adapt to different drilling conditions. The connection allows for relative movement or adjustment that can optimize both jamming prevention and fluid flow characteristics depending on the specific drilling application

Inventive Principle:
Principle #15Dynamics

2Quantity of substance

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

Engineering Contradiction:
Improvefluid flowVSAvoidstructure complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The second closed tubular element serves multiple functions: it provides structural support for torque transmission through the slot-shaped recesses, maintains the internal gap for fluid flow, and connects detachably to the first tubular element. This multi-functionality eliminates the need for separate transport channels, as the tubular element itself facilitates both mechanical and fluid functions

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

Solution Approach 2:

The use of closed tubular elements with thin-walled construction provides structural integrity while minimizing material usage. The tubular structure naturally creates internal flow passages without requiring additional transport channels, leveraging the hollow cylindrical geometry to achieve both structural and fluid transport functions

Inventive Principle:
Principle #30Flexible shells and thin films

3Adaptability or versatility

If a detachable connecting device is used to allow cutting section replacement, then adaptability is improved, but the device complexity increases

Engineering Contradiction:
Improvecutting section replaceabilityVSAvoidconnection device complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The cutting section is segmented into modular components (first closed tubular element, second closed tubular element, and drill segments) that can be independently replaced or adjusted. The detachable connection between tubular elements and between cutting section and drill shaft enables adaptability without requiring complex locking or securing mechanisms

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of making the entire cutting section irreplaceable with complex retention mechanisms, the design inverts the approach by using simple detachable connections that allow easy replacement. The slot-shaped recesses provide guidance and alignment while allowing straightforward assembly and disassembly without complex fastening systems

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

4Ease of manufacture

If the first closed tubular element is formed as a formed sheet metal part, then manufacturing effort is reduced, but the manufacturing precision may be affected

Engineering Contradiction:
Improvemanufacturing effortVSAvoiddimensional accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The forming process transforms flat sheet metal into three-dimensional tubular structures with specific geometric parameters (wave-shaped, trapezoidal, or zigzag cross-sections). By carefully controlling the forming parameters and material properties, the desired dimensional accuracy is achieved while maintaining the manufacturing efficiency of sheet metal forming processes

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The cutting section is divided into multiple tubular elements that can be formed separately from sheet metal and then connected. This segmentation allows each element to be optimized for forming processes while maintaining overall dimensional accuracy through precise connection interfaces and tolerances

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3727732B1Cutting section for a core bit
Publication Date: 2024.05.15 HILTI AG
  • EP3727732B1 patent drawingFigure 1A
  • EP3727732B1 patent drawingFigure 1B
  • EP3727732B1 patent drawingFigure 2A

AI summary

The invention relates to a cutting section (11) that can be connected to a drill shaft section by means of a detachable connecting device. The cutting section comprises a first closed tubular element (14) embodied in the form of a first hollow cylinder with a first wavy, trapezoidal or zig-zagging cross-sectional surface, a second closed tubular element (15) embodied in the form of a second hollow cylinder with a circular cross-sectional surface, and at least one drilling segment (16) connected to the first closed tubular element (14).