Core Drill Bit Torque Interface With Two-Level Rotary Drivers

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Solution Overview

Problem

Existing torque transmission devices for drilling machines are limited to 2.5 kW outputs, leading to high surface pressure and reduced service life when handling higher power levels, as they are not designed to transmit higher torques effectively.

Innovation Solution

The design incorporates lower rotary drivers on the base surface of the intermediate element and lower rotary driver grooves in the annular shoulder, increasing the contact area without height increase, allowing for the transmission of larger forces and torques with reduced surface pressure, and ensuring compatibility with new insertion ends while preventing connection with old tool holders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the existing torque transmission device is used for higher power outputs, then the power transmission capability is improved, but the surface pressure becomes very high leading to damage of drive pins and reduced service life

Engineering Contradiction:
Improvepower outputVSAvoidsurface pressure
Core Design Contradiction:
PowerVSStress or pressure

Solution Approach 1:

The invention transitions from a single-level rotary drive interface to a two-level structure with upper and lower rotary drivers. This dimensional change in the interface architecture allows torque transmission to be distributed across multiple contact surfaces, reducing surface pressure while maintaining or increasing power transmission capability

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The rotary drive interface is segmented into multiple drive pins and corresponding grooves distributed across upper and lower surfaces of the intermediate element. This segmentation distributes the contact pressure across multiple discrete contact points rather than concentrating it on a single interface, thereby reducing surface pressure and preventing damage

Inventive Principle:
Principle #1Segmentation

2Force

If the contact area between base body and intermediate element is increased to transmit greater forces, then the force transmission capability is improved, but the height of the rotary drive area must increase

Engineering Contradiction:
Improveforce transmissionVSAvoidheight of rotary drive area
Core Design Contradiction:
ForceVSLength of moving object

Solution Approach 1:

Instead of increasing contact area in the vertical dimension (height), the invention extends the contact surfaces horizontally by adding lower rotary drivers and grooves on the base surface. This lateral expansion of the interface allows greater force transmission without increasing the height of the rotary drive area

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Power

If the tool holder and insertion end are designed for higher torque transmission, then the torque capacity is improved, but compatibility with older systems is lost

Engineering Contradiction:
Improvetorque capacityVSAvoidsystem compatibility
Core Design Contradiction:
PowerVSAdaptability or versatility

Solution Approach 1:

The intermediate element is designed as a separate, replaceable component that bridges between the old tool holder and new insertion end. This segmentation allows the high-torque capability to be introduced through modular addition rather than requiring complete system replacement, preserving compatibility with older tool holders while enabling new capabilities

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The intermediate element serves as an intermediary component between the base body (tool holder) and the shank end (insertion end). It provides the enhanced torque transmission interface while maintaining compatibility with existing tool holders, acting as a mediator that enables both old and new system configurations

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4072757B1Device for transmitting torque from a drilling device to a core drill bit
Publication Date: 2023.09.06 HILTI AG
  • EP4072757B1 patent drawingFigure 1
  • EP4072757B1 patent drawingFigure 2A~2B
  • EP4072757B1 patent drawingFigure 3A~4B

AI summary

The invention relates to an apparatus (10) for transmitting a torque from a drill device to a core bit, having an insertion end (14) and a tool receptacle (13). The insertion end (14) is constructed from a first outer cone region, a groove region and a second outer cone region and comprises longitudinal grooves. The tool receptacle (13) is constructed from a main body (41), which has a rotary driving region having outer rotary driving grooves, an intermediate element (42), which comprises an inner driver region having inner rotary drivers and an outer driver region having outer rotary drivers, and an interlocking means (43). In the connected state, the inner rotary drivers engage in the longitudinal grooves and the outer rotary drivers engage in the outer rotary driving grooves. Lower rotary drivers are arranged on the base area of the intermediate element (42) and, in the connected state, interact with lower rotary driving grooves in the rotary driving region of the main body (41).