Rebar Coupler Structure for Torsion-Resistant Bar Locking
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Solution Overview
Problem
Conventional rebar couplers are inadequate in responding to torsion stress, have varying connection strength due to worker skill, and can result in uneven bonding with concrete, leading to structural weaknesses.
Innovation Solution
A rebar coupler design featuring cylindrical coupler bodies with inclined fixing piece contact surfaces, radial fixing pieces with sawtooth locking protrusions, and an elastic member to securely fix rebars while preventing locking protrusion wear and enhancing concrete bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional rebar couplers are designed only for tensile stress strength, then the coupling strength for tensile loading is sufficient, but the coupler cannot respond to torsion stress and the rebar rotates in the coupler when twisted
Solution Approach 1:
The fixing piece is designed with asymmetric locking protrusions having different shapes and orientations. Specifically, the first locking protrusion has a different configuration from the second locking protrusion, allowing them to engage with corresponding features on the rebar in different orientations. This asymmetric design enables the coupler to resist both tensile stress and torsion stress effectively, preventing rebar rotation while maintaining coupling strength.
2Device complexity
If the rebar coupler appearance is not considered for bonding strength with concrete, then the coupler structure is simple, but the bonding strength with concrete is weaker than rebars with nodes and ribs
Solution Approach 1:
The coupler body is designed with localized surface features including ribs and nodes on its outer circumference. These local structural elements are strategically positioned to enhance bonding with concrete in critical areas, while the overall coupler structure remains relatively simple. The fixing piece also incorporates localized locking protrusions that provide enhanced engagement without requiring complete redesign of the entire coupler architecture.
3Device complexity
If the fixing piece is installed inside a passage adjacent to the inlet, then the structure is compact, but the locking protrusion is easily worn down when the rebar is inserted slantly
Solution Approach 1:
The inlet passage is designed with a tapered configuration that guides the rebar end into proper alignment before it reaches the locking protrusions. This preliminary guiding action ensures that the rebar is correctly positioned prior to engagement with the locking protrusions, preventing slantwise insertion that would cause wear. The elastic member also provides preliminary contact to guide the rebar end, ensuring proper orientation before the locking protrusions engage.
4Ease of manufacture
If wires are used to tie rebars, then the rebars can be connected, but the work is inconvenient and the connected portion is easily cut
Solution Approach 1:
The invention replaces the wire-tying mechanical system with a mechanical coupling system consisting of a coupler body and fixing piece with locking protrusions. This mechanical coupling device provides permanent, durable connection that is resistant to cutting and loosening, while significantly improving ease of installation compared to wire tying. The elastic member provides automatic engagement and locking, eliminating the need for manual wire manipulation.
5Strength
If welding is used to connect rebars, then the rebars can be joined, but the welding work is inconvenient and the connection strength varies depending on worker skill
Solution Approach 1:
The invention replaces the welding process with a mechanical coupling system that provides uniform, predictable connection strength independent of worker skill. The locking protrusions and elastic member create a standardized mechanical engagement that delivers consistent performance across all installations, eliminating the variability inherent in manual welding operations while improving ease of operation.
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 rebar coupler effectively addresses torsion, tensile, and compressive stresses, ensures uniform bonding strength with concrete, and prevents locking protrusion wear, enhancing structural integrity and ease of assembly.
Implementation Method 1
an elastic member provided inside the coupler body to press the plurality of fixing pieces toward the inlet
Data Source
AI summary
The present invention relating to a rebar coupler that mutually connects and fixes a rebar in a longitudinal direction comprises: a pair of coupler bodies that are formed in a cylindrical shape through which the inside is penetrated, formed of an inlet in one side through which the rebar is inserted, and formed of a fixing piece contact surface inclined toward the inlet inside the penetrated passage; a connecting unit disposed between the pair of coupler bodies to mutually couple the opposite ends of the inlet of each coupler body; a plurality of fixing pieces arranged radially inside the coupler body, wherein an outer surface is installed to contact the fixing piece contact surface, and wherein a plurality of locking protrusions are formed in the horizontal and vertical directions, respectively, to fix the rebar inserted through the inlet; and an elastic member provided inside the coupler body to press the plurality of fixing pieces toward the inlet.