Hot-Swaged Rebar Coupling Sleeve for Shorter, Lower-Force Splices
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Solution Overview
Problem
Existing methods for connecting structural concrete reinforcing bars, such as welded lap splices and coupling sleeves, are labor-intensive, require significant overlap, and can lead to joint failure due to weldability issues with high-strength steel, making them inefficient and costly for retrofitting and repair applications.
Innovation Solution
A mobile or hand-held hot-swaged coupling device using a C-shaped sleeve and crimping process that requires less force, allows for precise alignment without twisting or moving the bars, and can connect bars of different sizes, eliminating the need for extensive training or special steel treatment, with interchangeable dies and induction heating for efficient bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welded lap splices are used to connect reinforcing bars, then the bars can be joined, but significant overlap (exceeding 80 inches) is required which limits application and increases labor and concrete waste
Solution Approach 1:
The patent changes the physical state of the coupling sleeve by heating it to a temperature where it becomes more malleable and easier to deform. This parameter change (temperature increase) allows the sleeve to be crimped onto the bars with significantly less force than cold swaging, enabling the use of much shorter overlap lengths while maintaining joint strength
Solution Approach 2:
The patent replaces the mechanical cold swaging process with a thermally-assisted crimping process. By substituting thermal energy for mechanical force, the system achieves the same coupling effect with reduced force requirements, allowing for more compact connections without compromising strength
2Strength
If cold-swaged coupling sleeves are used to connect reinforcing bars, then the bars can be joined, but the equipment is bulky and requires significant force to crimp the sleeve
Solution Approach 1:
The patent changes the physical state of the coupling sleeve by heating it to a temperature where it becomes more malleable and easier to deform. This parameter change (temperature increase) allows the sleeve to be crimped onto the bars with significantly less force than cold swaging, enabling the use of much shorter overlap lengths while maintaining joint strength
Solution Approach 2:
The patent utilizes a phase transition in the material properties of the coupling sleeve by heating it to its forging temperature. At this elevated temperature, the steel transitions from a hard, brittle state to a softer, more ductile state, fundamentally changing its mechanical properties to enable easier deformation with reduced force
3Strength
If arc welding is used to join reinforcing steel, then the bars can be connected, but the process requires certified welders, preheating, and slow cooling to prevent micro-cracking and embrittlement
Solution Approach 1:
The patent replaces the welding process with a mechanical crimping process assisted by thermal heating. This substitution eliminates the need for complex welding procedures, certified welders, preheating requirements, and controlled cooling processes, while achieving comparable or superior joint strength through a simpler, more straightforward operation
Solution Approach 2:
The patent uses a disposable or consumable heating element that is enclosed and contained within the device. This heating element can be replaced or regenerated without requiring complex welding equipment, specialized training, or extensive safety infrastructure, simplifying the overall system and operation
4Strength
If threaded couplers or grout-filled sleeves are used for coupling, then the bars can be connected, but additional concrete cover is required and the equipment is bulky
Solution Approach 1:
The patent changes the physical state of the coupling sleeve by heating it to a temperature where it becomes more malleable and easier to deform. This parameter change (temperature increase) allows the sleeve to be crimped onto the bars with significantly less force than cold swaging, enabling the use of much shorter overlap lengths while maintaining joint strength
Solution Approach 2:
The patent uses a C-shaped coupling sleeve that is segmented or open-ended in design, allowing it to be placed around the bars and then crimped closed. This segmented approach enables the sleeve to conform to the bars and create a tight mechanical connection without requiring bulky end caps or extensive concrete encasement
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 significantly reduces labor and material waste, enhances installation speed, and ensures high-quality connections with improved safety and quality control, enabling efficient retrofitting and repair while minimizing reinforcement congestion and the need for bulky equipment.
Implementation Method 1
The induction heater is comprised of an electrically conductive metal tube formed into a semi-circle coil shape that is positioned to closely approach the coupling sleeve when the device is in the closed position
Implementation Method 2
The actuator is in the form of a hydraulic piston that is located inside the housing
Data Source
AI summary
A method of spicing together and joining ends of a first member and a second member includes the steps of: arranging the ends of the first member and the second member in side-by-side manner; placing a coupling sleeve over the ends of the first member and the second member; and using a portable, hot-swaged coupling device to heat and crimp the coupling sleeve about the ends of the first and second member, thereby joining the ends of the first and second members.