Fastening Anchor with Reduced-Diameter Thread for Brittle Materials

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Solution Overview

Problem

Existing fastening anchors for screwing into boreholes in brittle materials like natural stone and rock salt face issues with high screwing torque due to deviations in straightness, leading to potential destruction and limited screwing depth.

Innovation Solution

A fastening anchor design with a fastening thread diameter smaller than the cutting core diameter, allowing for flexible screwing depth without increased torque, featuring a torque transmission means and a composite mass for enhanced adhesion and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the fastening anchor is screwed into the borehole with the fastening thread having essentially identical outer diameter to the borehole inner diameter, then the anchor can be securely fastened, but the screwing torque increases excessively and may destroy the anchor

Engineering Contradiction:
Improvefastening strengthVSAvoidscrewing torque
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The patent applies local quality by creating a reduced-diameter section in the fastening anchor body at the fastening thread location. This local reduction in diameter ensures that the fastening thread does not contact the borehole wall, eliminating friction and excessive screwing torque while maintaining secure fastening capability. The reduced diameter section is specifically positioned where the fastening thread is formed, allowing the anchor to be screwed in with significantly reduced torque.

Inventive Principle:
Principle #3Local quality

2Force

If the fastening anchor has a straight central longitudinal axis with tight tolerances, then the screwing torque is reduced, but the manufacturing complexity and costs increase

Engineering Contradiction:
Improvescrewing torqueVSAvoidstraightness tolerance
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

Instead of requiring the entire fastening anchor to have tight straightness tolerances, the patent applies local quality by creating a reduced-diameter section only at the fastening thread location. This localized modification allows greater tolerance in the overall anchor straightness while still preventing contact between the fastening thread and borehole wall, thereby reducing screwing torque without increasing manufacturing complexity.

Inventive Principle:
Principle #3Local quality

3Length of moving object

If the cutting thread extends along the entire length of the anchor, then the screwing depth is maximized, but the anchor cannot be screwed in safely due to excessive torque

Engineering Contradiction:
Improvescrewing depthVSAvoidsafe screwing
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent applies segmentation by dividing the anchor body into distinct sections: a reduced-diameter section at the fastening thread location and a full-diameter section at the cutting thread location. This segmentation allows the cutting thread to extend along the full length for maximum screwing depth while the reduced-diameter section ensures safe screwing by preventing excessive torque generation at the fastening location.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2691659B1Fastening anchor and fastening device
Publication Date: 2016.07.27 TOGE DUBEL
  • EP2691659B1 patent drawingFigure 1

AI summary

A fastening anchor (6) for screwing into a borehole (3) in a brittle material (2) comprises a core (7), a cutting thread (12) which is formed in one piece with the core (7) and which extends along a cutting portion (As) and which serves for screwing said core into the material and which has a cutting core diameter (DSK) and a cutting thread diameter (DSG), a fastening thread (16) which is formed in one piece with the core (7) and which extends at least in sections along a fastening portion (AB) and which serves for fastening a fastening element with a fastening core diameter (DKB) and a fastening thread diameter (DBG), and a torque transmission means (18) which is arranged on the core (7) and which serves for screwing the latter into the material, wherein the fastening thread diameter (DBG) is smaller than the greatest cutting core diameter (DSK).