Vibration-Cured Dowel Anchoring for Hollow Bricks and Concrete

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Solution Overview

Problem

Existing anchoring methods for objects with low density and/or low mechanical strength, such as hollow bricks or dense materials like concrete, face limitations in anchoring strength and reliability due to limited expansion and require time-consuming curing processes, often compromised by drill dust.

Innovation Solution

A method involving mechanical vibration energy to impinge on a hardenable composition between an insert portion and the object, causing chemical hardening and forming connections, which includes simultaneous or sequential insertion, using a sonotrode for efficient energy transfer and incorporating resilient elements to control vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If special dowels are pushed into pre-drilled holes and allowed to spread to anchor screws in hollow bricks, then anchoring is achieved despite hollow spaces, but anchoring strength is limited due to limited expansion space

Engineering Contradiction:
Improveanchoring strengthVSAvoidaxial extension of hollow spaces
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent replaces the mechanical expansion system with a chemical hardening system. Instead of relying on mechanical spreading of the dowel to achieve anchoring, the invention uses chemical reactions (curable resin hardening) to create a strong bond between the insert portion, hollow spaces, and surrounding material, eliminating the need for mechanical expansion.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the state of the resin from liquid/pasty to solid through chemical hardening. This parameter change allows the resin to fill hollow spaces effectively in liquid state, then provides strong anchoring strength after hardening, resolving the contradiction between limited space and required anchoring strength.

Inventive Principle:
Principle #35Parameter changes

2Strength

If curable resins are used to fasten objects in dense materials like concrete, then very strong connections are achieved, but curing takes a lot of time making processes more complicated and expensive

Engineering Contradiction:
Improveconnection strengthVSAvoidcuring time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The patent applies mechanical vibration during the hardening process to accelerate the chemical reaction of the curable resin. The vibration energy impinges on the resin between the insert portion and the opening wall, speeding up curing time while maintaining the strong connection strength provided by the chemical hardening.

Inventive Principle:
Principle #18Mechanical vibration

3Strength

If curable resins are used for anchoring in dense materials, then strong connections are achieved, but drill dust or debris at the interface may cause the connection to become unreliable and fail

Engineering Contradiction:
Improveconnection strengthVSAvoidconnection reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The mechanical vibration applied during the process serves dual purposes: it accelerates the hardening reaction and simultaneously removes drill dust and debris from the interface between the resin and the opening wall. This ensures a clean bonding surface and reliable connection.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The patent converts the potentially harmful effect of drill dust into a beneficial process. The mechanical vibration that could potentially disturb the interface instead effectively removes debris and contaminants, transforming a risk factor into a cleaning mechanism that improves connection reliability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Productivity

If mechanical vibration energy is applied to accelerate hardening, then curing time is reduced and process efficiency is improved, but additional equipment and process complexity are introduced

Engineering Contradiction:
Improvehardening speedVSAvoidprocess complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent makes the insert portion multi-functional by integrating it with the vibration generation system. The insert portion serves both as the anchoring element and as the medium for transmitting vibration energy to the resin, eliminating the need for separate vibration generation equipment and reducing overall system complexity.

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

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

Enhances anchoring strength, reduces curing time, integrates debris, and ensures reliable connections by improving the hardening process efficiency and stability, suitable for a variety of materials including dense and low ductility objects.

Implementation Method 1

causing mechanical vibration energy to impinge to cause the hardenable composition to undergo a chemical hardening process

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 2

the hardenable composition undergoes a chemical hardening process to yield a hardened composition

Methodology Applied
Scientific EffectChemical hardening: Chemical Bonding

Implementation Method 3

The first object is mechanically coupled to a sonotrode, which vibrates during the step of causing the mechanical vibration energy to impinge on the hardenable composition

Methodology Applied
Scientific EffectMechanical coupling: Mechanical Force

Implementation Method 4

The mechanical vibration energy also causes the hardenable composition to interpenetrate structures of the second object

Methodology Applied
Scientific EffectInterpenetration: Capillary Action

Implementation Method 5

A resilient element may be placed between a distal end of the insert portion and a bottom of the opening

Methodology Applied
Scientific EffectVibration damping: Damping

Data Source

PatentEP4301992B1Anchoring a dowel in an object
Publication Date: 2025.12.31 WOODWELDING AG
  • EP4301992B1 patent drawingFigure 1~6
  • EP4301992B1 patent drawingFigure 7~10
  • EP4301992B1 patent drawingFigure 11~15

AI summary

A method of anchoring a first object (1) in a second object (2) is provided. The second object (2) comprises an opening (21). Such opening (21) may for example by provided by drilling into the second object. The first object (1) has an insert (11) portion that defines an insertion axis (30) and has an outer shape that may form an undercut with respect to axial directions. The method comprises inserting the insert portion (11) in the opening, with a hardenable composition (prepolymer; mortar; 5) between a wall of the opening and the insert portion (11), and causing mechanical vibration energy to impinge to cause the hardenable composition (5) to undergo a chemical hardening process to yield a hardened composition, so that a first connection between the first object and the hardened composition and a second connection between the hardened composition and the second object results, whereby the first object (1) is anchored in the second object (2). The first connection and/or the second connection may comprise an adhesive connection and/or a positive-fit connection.