Threaded Rebar Coupling Sleeve With Variable Rib for Concrete Adhesion
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Solution Overview
Problem
Existing end-to-end connection systems for steel reinforcing bars in reinforced concrete structures face challenges in achieving optimal mechanical and adhesion properties due to limitations in steel grade, bar diameter, and geometry, leading to inconsistent mechanical characteristics and difficulty in controlling the connection's resistance to tensile forces and adhesion to concrete.
Innovation Solution
A sleeve with a substantially tubular steel body featuring an uninterrupted central rib and end ribs, internally threaded with variable width, and nuts with a flared portion and indentations, optimized through machining or forging to enhance resistance and adhesion, allowing for tailored geometric and mechanical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If sleeves are manufactured from high adhesion reinforcements by cutting and drilling, then adhesion to concrete is improved, but the ability to choose steel grade, bar diameter, and asperity geometry is lost
Solution Approach 1:
The invention separates the manufacturing process into two independent parts: the sleeve body (which can be made from any steel grade and diameter) and the asperities (which are added separately through forging). This segmentation allows independent optimization of each component's properties, resolving the contradiction between adhesion strength and manufacturing flexibility.
Solution Approach 2:
The asperities are formed by forging the sleeve blank before the final machining operations. This preliminary action of creating the adhesion-enhancing surface features early in the manufacturing process allows subsequent operations to precisely control steel grade, diameter, and geometry without compromising the asperity structure.
2Strength
If sleeves are manufactured by forging with heat treatment and cavity formation, then mechanical characteristics can be optimized, but uniform shrinkage and rib positioning control become difficult
Solution Approach 1:
The invention extracts the asperity formation step from the complex forging process with multiple cavities and partitions. Instead of trying to control uniform shrinkage through complex tooling, the asperities are formed by a simpler forging action that pushes material outward, eliminating the need for precise partition placement and uniform shrinkage control while maintaining mechanical strength.
3Strength
If the sleeve wall is shrunk to form external ribs, then adhesion to concrete is improved, but the position and depth of ribs cannot be perfectly controlled
Solution Approach 1:
The invention transitions from a static, fixed-tooling approach to forming ribs to a dynamic process where the forging action itself creates the asperities. The forging process naturally forms the surface features through material flow and deformation, allowing better control over position and depth by adjusting forging parameters rather than relying on rigid tooling geometry.
Data Source
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AI summary
The invention relates to a sleeve (23) for the butt joint of two threaded reinforcements (25, 26), which comprises a substantially tubular steel body which is internally threaded; the body is provided with a central rib (39) which extends along a circumference of the body, and the central rib is uninterrupted, bordered on both sides by impressions (30, 31), and has a variable width along the circumference, and the sleeve is traversed by a threaded longitudinal passage (22).