Locking Anchor Anti-Rotation Structure for Stable Formwork Fastening

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Solution Overview

Problem

Existing anchoring elements for climbing formwork in concrete structures often result in concrete damage such as cracks or breakouts due to thread play caused by the threaded rod rotating within the locking anchor, leading to a loose connection that collapses under load.

Innovation Solution

An anchoring element with a rotation-proof securing element, typically a plastic tongue, that prevents the threaded rod from unscrewing, combined with a conically widening coupling element and a sleeve for easier removal, ensuring a secure and stable connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the threaded rod is allowed to rotate freely in the threaded hole during concrete vibration, then the coupling element can be easily installed and removed, but the threaded rod rotates independently creating thread play and the connection becomes loose under load

Engineering Contradiction:
Improveease of installation and removalVSAvoidconnection stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention divides the coupling element into two functional parts: a threaded rod for screwing into the anchor, and a separate securing element (such as a tongue or locking mechanism) that independently prevents rotation. This segmentation allows the threaded rod to maintain easy threading while the securing element provides rotation prevention, resolving the contradiction between ease of operation and connection stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The securing element acts as an intermediary component between the threaded rod and the anchor hole. It mediates the interaction by providing the rotation-proof function separately from the threading function, allowing the threaded rod to be screwed in easily while the securing element independently ensures the rod cannot rotate independently, thus maintaining connection stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a rotation-proof securing element is added to prevent the threaded rod from unscrewing, then connection stability is improved, but the device complexity increases

Engineering Contradiction:
Improveconnection stabilityVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the rotation-proof function from the main body of the coupling element and implements it as a separate, dedicated securing element. This extraction allows the core threading function to remain simple while the anti-rotation function is added as a distinct component, minimizing the increase in overall device complexity while ensuring connection stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The securing element is designed as a simple, inexpensive component (such as a plastic tongue or basic locking mechanism) that can be easily manufactured and integrated. By using a simple, low-cost securing element rather than a complex mechanical system, the invention adds minimal complexity to the overall device while effectively preventing rotation and ensuring connection stability.

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

3Ease of operation

If the coupling element has a conical shape for easier removal, then the ease of operation is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveease of removalVSAvoidconical shape precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The invention changes the geometric parameter of the coupling element from a cylindrical to a conical shape. This parameter change allows the coupling element to be easily removed by twisting or pulling, as the conical shape creates a tapered fit that reduces friction and facilitates extraction from the hardened concrete, while the conical geometry can be manufactured with standard precision tolerances.

Inventive Principle:
Principle #35Parameter changes

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 solution effectively prevents concrete damage by maintaining a secure connection during concrete vibration and hardening, allowing for reliable attachment and detachment of climbing formwork without causing structural issues.

Implementation Method 1

The frictional connection between the locking element and the threaded rod prevents it from unscrewing, for example when shaking

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The conical shape allows for easier removal of the coupling element from the hardened concrete

Methodology Applied
Scientific EffectFriction reduction through conical geometry: Friction

Data Source

PatentEP3421822B1Locking anchor with Anti-rotation feature
Publication Date: 2021.11.10 DOKA GMBH
  • EP3421822B1 patent drawingFigure 1
  • EP3421822B1 patent drawingFigure 2
  • EP3421822B1 patent drawingFigure 3

AI summary

The invention relates to an anchoring element (1) for fastening a climbing formwork to a concrete body, comprising a locking anchor (10) and a coupling element (20), wherein the locking anchor has a head (11) and a threaded rod (12) with an external thread (13), and wherein the coupling element is formed by an elongated circular body with an axial anchor bore (25) having an internal thread (26) that engages with the external thread (13) of the threaded rod. According to the invention, a locking element (35, 40) is provided which acts frictionally on the external thread of the threaded rod and/or the internal thread of the anchor bore and is suitable for preventing the threaded rod received in the anchor bore from unscrewing.