Reinforcing Rod Tapered End Thread Root Diameter

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Solution Overview

Problem

Existing reinforcing bars for reinforced concrete face challenges in assembly due to potential breakage and deformation at the threaded end, leading to increased costs and risks of rupture, especially when the bar is heavy or bent, and access is difficult.

Innovation Solution

A high-adhesion reinforcing bar design featuring an extension portion with hooking asperities and an upturned end portion with a thread where the thread root diameter is greater than or equal to the nominal diameter, and a second part with a decreasing section length greater than the first part, reducing the risk of crystalline structure degradation and deformation during assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the upturned end portion is made by cold upsetting of a large portion of the reinforcement bar, then the assembly of reinforcing bars can be carried out easily, but the crystalline structure of the reinforcement bar is modified causing embrittlement and risk of rupture

Engineering Contradiction:
Improveassembly easeVSAvoidrupture risk
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies local quality by creating a tapered portion with gradually decreasing section, where the deformation is distributed along a longer length rather than concentrated. This gradual transition zone allows the material to deform more uniformly, reducing stress concentrations that would otherwise cause embrittlement and rupture in the threaded portion.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The upturned end portion is segmented into distinct zones: a first portion with the thread, a tapered portion with gradually decreasing section, and a second portion with constant section. This segmentation allows each zone to serve a specific function - the tapered portion acts as a transition zone that distributes deformation, protecting the threaded portion from excessive stress.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If the upturned end portion is made by cold upsetting of a large portion of the reinforcement bar, then the thread can be formed on the enlarged diameter, but permanent deformation occurs during tensioning

Engineering Contradiction:
Improvethread formationVSAvoidpermanent deformation
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent creates a localized tapered portion with controlled geometry where the section gradually decreases. This localized deformation zone is designed to accommodate the cold upsetting process while limiting the extent of plastic deformation to a controlled region, preventing permanent deformation from propagating to the main body of the reinforcement bar during tensioning.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The tapered portion is formed in advance during manufacturing, creating a pre-defined deformation zone with optimized geometry. This preliminary action prepares the material structure to accommodate subsequent threading and assembly operations without causing unwanted permanent deformation during service loading.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the reinforcement bar is oversized to avoid rupture and deformation, then reliability is improved, but manufacturing costs increase

Engineering Contradiction:
Improverupture preventionVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of oversizing the entire reinforcement bar, the patent applies local quality by creating a specialized tapered portion with optimized geometry at the upturned end. This localized structural modification provides the necessary deformation accommodation and stress distribution to prevent rupture, while the rest of the bar maintains its original, more economical dimensions.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes geometric parameters locally by introducing a tapered portion with a specific length-to-diameter ratio and gradual section decrease. This parameter modification in the critical zone allows the bar to accommodate deformation without requiring an overall increase in bar diameter, thus avoiding the cost increase associated with oversized reinforcement bars.

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

This design ensures reliable and easy assembly of the reinforcement while minimizing the risk of rupture and deformation, without the need for oversizing the reinforcing bar, thus reducing manufacturing costs.

Implementation Method 1

extension portion (3) comprising, on its outer surface, hooking asperities (6, 7) intended to promote adhesion between the reinforcing bar and the concrete

Methodology Applied
Scientific EffectMechanical interlocking: Mechanical Fastener

Data Source

PatentEP3004483B1Reinforcing rod with high adherence for reinforced concrete
Publication Date: 2017.11.15 MAGNETUD
  • EP3004483B1 patent drawingFigure 1~2
  • EP3004483B1 patent drawingFigure 3~4
  • EP3004483B1 patent drawingFigure 5~6

AI summary

Reinforcing rod with high adherence for reinforced concrete The reinforcing rod (2) according to the invention comprises an extension portion (3) including, on its outer surfaces, catching asperities (6, 7) intended to promote adherence between the reinforcing rod and the concrete, and an upset end portion (4) provided with a threading (8) intended to cooperate with a tapping arranged in a connecting sleeve, the thread bottom diameter of the threading (8) being larger than the nominal diameter of the reinforcing rod. The upset end portion (4) includes a substantially cylindrical first part (41), and at least one second part (42) positioned between the first part and the extension portion, the second part (41) having a general section decreasing toward the extension portion and having a length greater than or equal to the length of the first part (41).