Core Drill Toolholder With Damped Union Nut Against Loosening

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Solution Overview

Problem

Existing devices for securing drill bits on core drilling machines face challenges with difficult assembly and disassembly, risk of loosening due to vibrations and shocks, and potential damage from contamination or external forces, requiring specialized tools and leading to incorrect functioning or failure.

Innovation Solution

A device featuring a union nut with a stop disk and damping element, along with a retaining ring, allows for tool-free assembly and secure attachment of drill bits to the machine tool, preventing loosening during operation through a non-positive connection and internal threading, and utilizing a plastic union nut for easier handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a threaded connection (BS interface) is used to connect the output shaft to the drill bit, then the drill bit can be securely attached to transmit high torque, but assembly and disassembly require specialized tools and become extremely difficult under high friction conditions

Engineering Contradiction:
Improvetorque transmission capabilityVSAvoidassembly and disassembly ease
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The connection system is divided into separate functional elements: a retaining ring on the output shaft, a stop disk on the drill bit, and a union nut that secures them together. This segmentation allows the connection to be made and broken by simply sliding the union nut onto or off the threaded portion, eliminating the need for specialized wrench keys while maintaining secure torque transmission through the threaded engagement between the union nut and drill bit connection piece

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The union nut acts as an intermediary element that mediates between the output shaft and the drill bit. It provides the threaded connection for secure attachment while its design with the stop disk interacting with the retaining ring enables tool-free assembly and disassembly, resolving the contradiction between strong connection and ease of operation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a threaded connection is used under extreme stress with high torque, then secure connection is achieved, but vibrations and shocks can cause the connection to loosen or create excessive friction requiring great force to loosen

Engineering Contradiction:
Improveconnection stability during drillingVSAvoiddisassembly difficulty
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The damping element is positioned between the stop disk and the inner surface of the union nut to beforehand cushion against vibrations and shocks during drilling operations. This damping element absorbs the harmful vibrations and shocks, preventing them from causing the connection to loosen or creating excessive friction that would make disassembly difficult, while maintaining reliable connection stability during operation

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Ease of operation

If a simple threaded connection is used, then assembly is relatively easy, but contamination from drilling dust or external forces can damage components leading to incorrect functioning or complete failure

Engineering Contradiction:
Improveassembly simplicityVSAvoidsusceptibility to contamination and damage
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The connection system is segmented into separate components (retaining ring, stop disk, damping element, union nut) that can be independently protected. The damping element specifically protects the threaded connection from contamination by drilling dust, while the overall design maintains assembly simplicity through tool-free operation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The damping element serves as an intermediary barrier between the threaded connection components and the contaminated drilling environment. It protects the threads from drilling dust contamination while allowing the simple threaded assembly mechanism to remain effective

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables simple and secure attachment and detachment of drill bits without tools, maintaining a stable connection during drilling operations, reducing the risk of damage and ensuring reliable tool performance.

Implementation Method 1

a damping element (27), with the stop disk (26) being positioned between the retaining ring (25) and the damping element (27)... The damping element (27) can be used to prevent the union nut (22) from loosening in the event of vibrations during operation of the machine tool

Methodology Applied
Scientific EffectVibration damping: Damping

Data Source

PatentEP3172002B1Toolholder for the connection of a drilling unit with a hollow diamond drilling tool
Publication Date: 2021.07.07 HILTI AG
  • EP3172002B1 patent drawingFigure 1
  • EP3172002B1 patent drawingFigure 2
  • EP3172002B1 patent drawingFigure 3

AI summary

Device (20) for receiving and securing a tool (2; Fig. 1), in particular a drill bit, to a machine tool (1; Fig. 1), for example a core drill, containing an output shaft (6) for transmitting a torque generated in the machine tool (1) to the tool (2); and a union nut (22), positioned around the output shaft (6), for releasably connecting the output shaft (6) to a connection end (9) of the tool (2). The output shaft (6) contains a retaining ring (25) and the union nut (22) contains a stop washer (26) and a damping element (27), wherein the stop washer (26) is positioned between the retaining ring (25) and the damping element (27).