Concave Anchor Dowel for Concrete Tensile Load Distribution

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Solution Overview

Problem

Existing anchor plugs are unable to effectively absorb high forces, particularly tensile forces, leading to damage and potential collapse of structures like double walls, as they concentrate stress peaks in brittle materials like concrete, resulting in sudden loss of load-bearing capacity.

Innovation Solution

An anchor dowel with a concavely curved surface pointing towards the tensile force direction, made of plastic with an internal thread and optional reinforcement, distributes forces over a larger area, enhancing load-bearing capacity and resilience through homogeneous stress distribution and flexible material properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional anchor plugs with flat surfaces are used, then the structure is simple and easy to manufacture, but the load-bearing capacity is limited and stress peaks cause concrete damage

Engineering Contradiction:
Improveload-bearing capacityVSAvoidanchor dowel geometry
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The anchor dowel features a concavely curved surface (hyperbolic or parabolic contour) instead of a flat surface. This curvature distributes tensile forces over a larger area of the surrounding concrete, reducing stress peaks and preventing localized concrete damage while maintaining high load-bearing capacity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameters of the anchor dowel surface from flat to concavely curved. This parameter change transforms the stress distribution pattern from concentrated to distributed, allowing the anchor to withstand higher tensile forces without causing concrete failure.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If anchor plugs made of rigid materials are used, then manufacturing precision is easier to achieve, but the material cannot compensate for pressure differences and stress peaks

Engineering Contradiction:
Improveresilience under loadVSAvoidmaterial selection
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the material parameter from rigid (metal) to elastic (plastic). This allows the anchor dowel to compensate for pressure differences and stress peaks through elastic deformation, improving reliability under varying load conditions while remaining manufacturable through injection molding.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The anchor dowel can be made from plastic materials with added fillers or reinforcements (such as glass fibers or metal inserts). This composite approach combines the elasticity and stress-distribution benefits of plastic with the strength and rigidity of reinforcing materials, achieving both resilience and manufacturability.

Inventive Principle:
Principle #40Composite materials

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

The anchor dowel significantly increases the load-bearing capacity and resilience of connections, allowing for higher tensile force absorption and maintaining load-bearing capacity even after initial crack formation, reducing the risk of structural failure.

Implementation Method 1

Compared to other possible materials, such as metal, plastic exhibits higher elasticity, which allows it to compensate for pressure differences under load

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

This design of the surface facing the direction of the tensile force ensures that forces introduced into the anchor bolt and the surrounding mass, for example concrete, are distributed over a large area. This reduces stress peaks and thus local overloads of the material surrounding and supporting the anchor bolt

Methodology Applied
Scientific EffectStress distribution:

Data Source

PatentEP3161226B1Anchor dowel
Publication Date: 2020.07.29 PFEIFER HOLDING GMBH & CO KG
  • EP3161226B1 patent drawingFigure 1A~1B
  • EP3161226B1 patent drawingFigure 2A~2B
  • EP3161226B1 patent drawingFigure 3

AI summary

The invention relates to an anchor dowel (2, 2') which is to be embedded in a mass that can be poured and set, in particular concrete (42), said dowel having a receiving section (6) for a connecting element (34, 36) that is to be held by means of the anchor dowel (2, 2'). The anchor dowel (2, 2') has a surface (4) facing the direction (Z) of tensile force, said surface being substantially concave.