Centering Ring Tool for Precise Wall Opening in Installed Lines

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Solution Overview

Problem

Existing tools, such as hole saws, are unable to create a coordinated wall opening for prefabricated fire protection grommets when cables or pipes are already installed in drywall, requiring the use of a pasty sealing compound to create an annular gap instead.

Innovation Solution

A tool with a centering device designed as a centering ring that can be inserted around a line protruding from the wall, allowing a hole saw to be slid onto the line transversely and rotated to create a precise opening for fire protection grommets, usable for both installed and yet-to-be-installed lines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a hole saw is used to create a wall opening, then an opening can be made in drywall, but it cannot create a coordinated opening for fire protection grommets when a line is already installed

Engineering Contradiction:
Improveadaptability to different installation scenariosVSAvoidprecision of wall opening
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The tool is divided into two functional segments: a centering ring for positioning and a hole saw for cutting. The centering ring can be independently positioned on the line, while the hole saw is then inserted into the centering ring to create the opening. This segmentation allows each component to perform its specific function optimally.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The centering ring acts as an intermediary between the installed line and the hole saw. It bridges the gap by first positioning itself on the line, then receiving the hole saw to create the precisely sized opening. This intermediary enables the tool to adapt to both installed and non-installed line scenarios.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a prefabricated fire protection grommet is used, then fire protection is provided, but it requires an existing opening tailored to the grommet which cannot be created with conventional hole saws

Engineering Contradiction:
Improvefire protection reliabilityVSAvoidease of installation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The centering ring is designed with a diameter that corresponds to the outer diameter of the fire protection grommet. By positioning the centering ring on the line first, the subsequent hole saw cutting automatically creates an opening that is pre-tailored to receive the grommet, eliminating the need for manual measurement and adjustment.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The tool changes the critical parameter of opening diameter by using the centering ring's fixed diameter as a reference. This ensures the opening diameter matches the grommet diameter, transforming the installation process from one requiring manual precision to one with built-in dimensional control.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If an annular gap is created around an installed line using sealing compound, then cable passage is enabled, but it requires pasty compound installation rather than preformed grommets

Engineering Contradiction:
Improveease of cable passage creationVSAvoidfire protection and soundproofing quality
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention replaces the temporary, non-structural sealing compound solution with a permanent, structurally sound prefabricated grommet. The grommet provides lasting fire protection and soundproofing, whereas the sealing compound is merely a temporary measure that lacks structural integrity and protective properties.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP3356069B1Tool for making a hole in a wall and method for making a hole in a wall with such a tool
Publication Date: 2020.11.25 HILTI AG
  • EP3356069B1 patent drawingFigure 1
  • EP3356069B1 patent drawingFigure 2~5
  • EP3356069B1 patent drawingFigure 6~7

AI summary

Tool (100) for producing an opening (220) in a wall using a keyhole saw (10) and a centring device which has a centring axis (A) running through the centre point of the keyhole saw (10), wherein the centring device is embodied as a centring ring (20) into which the keyhole saw can be at least partially inserted, and wherein both the keyhole saw (10) and the centring ring (20) have on their circumference an opening (11, 21) such that said opening (11, 21) can be fitted completely onto a line (300) transversely with respect to the centring axis (A).