Core Bit Cutting Section With Nested Tubes for Torque Transfer

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Solution Overview

Problem

Existing cutting sections for drill bits, such as the 'Hilti DD X-CM', face high manufacturing efforts due to turning and milling requirements, and have limited material selection, which affects power transmission, torque transmission, and tensile loads during drilling and jammed bit removal.

Innovation Solution

The cutting section is designed with a first and second closed tubular element, allowing separate optimization for force and torque transmission, featuring a nested structure with slot-shaped recesses for relative movement and a T- or L-shaped slot for easy jam release, reducing manufacturing complexity and enabling material selection based on specific requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If cutting sections are manufactured from a closed tubular element with turned annular stop shoulder and milled slotted recesses, then force and torque transmission are achieved, but manufacturing effort and complexity increase significantly

Engineering Contradiction:
Improveforce and torque transmissionVSAvoidmanufacturing effort
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The cutting section is divided into two separate closed tubular elements instead of being manufactured as a single integrated component. The first closed tubular element contains the annular stop shoulder for force transmission, while the second closed tubular element contains the slot-shaped recesses for torque transmission. This segmentation allows each element to be manufactured independently using simpler processes, eliminating the need for complex turning and milling operations on a single monolithic structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first closed tubular element is inserted into the second closed tubular element, creating a nested configuration. The annular stop shoulder of the first element engages with the drill shaft section, while the slot-shaped recesses in the second element receive pin elements for torque transmission. This nesting arrangement allows both force and torque transmission functions to be achieved through simple insertion and engagement, rather than complex machining operations.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Stability of the object's composition

If cutting sections are manufactured from a single closed tubular element, then structural integrity is maintained, but material selection is limited and cannot be optimized for specific functions

Engineering Contradiction:
Improvestructural integrityVSAvoidmaterial selection
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The cutting section is segmented into two separate closed tubular elements, each of which can be manufactured from different materials optimized for their specific functions. The first element can be made from a material optimized for force transmission and annular stop shoulder engagement, while the second element can be made from a material optimized for torque transmission through slot-shaped recesses. This segmentation enables independent material selection for each functional component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different materials can be assigned to different regions (tubular elements) based on their specific functional requirements. The first closed tubular element can use a material with high compressive strength for force transmission, while the second element can use a material with high shear strength for torque transmission. This local optimization of material properties enhances overall performance while maintaining structural integrity through the nested connection.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If traditional turning and milling processes are used to create annular stop shoulder and slotted recesses, then precise geometric features are achieved, but manufacturing time and cost increase

Engineering Contradiction:
Improvegeometric precisionVSAvoidmanufacturing time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The complex geometric features are distributed across two separate tubular elements that can be manufactured using simpler, faster processes. The annular stop shoulder is formed on the first element as a simple rim feature, while the slot-shaped recesses are formed on the second element as straightforward cutouts. This segmentation eliminates the need for complex multi-step turning and milling operations on a single component, significantly reducing manufacturing time while maintaining sufficient geometric precision for functional engagement.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3727731B1Cutting section for a core bit
Publication Date: 2024.04.03 HILTI AG
  • EP3727731B1 patent drawingFigure 1A
  • EP3727731B1 patent drawingFigure 1B
  • EP3727731B1 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 closed tubular element (14) which is formed in the shape of a first hollow cylinder, a second closed tubular element (15) which is formed in the shape of a second hollow cylinder, and one or more drill segments (16) which are connected to the first closed tubular element (14) and the second closed tubular element (15).