Hot-Dip Galvanized U-Type Shackle for Overhead Lines
The U-type shackle is a load-bearing connecting fitting designed for overhead transmission and distribution-line hardware assemblies. Its U-shaped body and removable cross bolt provide a secure articulated connection between insulator strings, clamps, link fittings, tower attachments and other compatible components.
The fitting consists of a U-shaped steel body, transverse bolt, nut, washers and retaining cotter pin. The removable bolt allows adjoining hardware to be positioned between the two sides of the shackle before the connection is secured.
Different U-series models are available for different coupling dimensions and specified mechanical failure loads. Selection must be based on the complete hardware-string drawing, adjoining fitting dimensions and required load class.
Important: This product is an overhead-line fitting. It must not be presented or used as general lifting or rigging equipment unless the exact model has been separately designed, tested and certified for that application.
Key Features
- U-shaped body for articulated hardware connections
- Removable transverse bolt for straightforward assembly
- Nut and retaining cotter pin help prevent accidental disassembly
- Designed for load transfer within overhead-line hardware strings
- Compatible with appropriately sized eye, clevis and plate fittings
- Hot-dip galvanized surface for outdoor corrosion protection
- Multiple coupling dimensions and mechanical load classes available
- Dimensions, material, coating and marking can be customized
Typical Technical Specifications
| Product Type | U-Type Shackle / U-Shaped Link Fitting |
|---|---|
| Construction | U-shaped body, cross bolt, nut, washers and retaining cotter pin |
| Representative Models | U-7, U-10, U-12 and U-16 |
| Body Material | Load-bearing carbon steel, subject to the approved material specification |
| Bolt and Nut Material | Carbon steel |
| Cotter Pin Material | Stainless steel or corrosion-resistant steel, according to the approved drawing |
| Surface Finish | Hot-dip galvanized |
| Connection Method | Removable bolt-and-pin connection |
| Application | Insulator strings, suspension assemblies, tension assemblies and overhead-line link fittings |
| Installation Location | Transmission line, distribution line or substation |
| Customization | Model, dimensions, load class, steel grade, coating, marking and packaging |
Representative U-Series Load Classes
| Model | Representative Specified Failure Load |
|---|---|
| U-7 | 70 kN |
| U-10 | 100 kN |
| U-12 | 120 kN |
| U-16 | 160 kN |
The load classes above are representative industry selection data. They must not be treated as guaranteed performance for the photographed products until confirmed by the approved drawing and mechanical test report.
Applications
- Suspension insulator-string assemblies
- Tension insulator-string assemblies
- Connection between clamps and insulator strings
- Connection between link plates and tower-side fittings
- Overhead ground-wire hardware assemblies
- ADSS and OPGW suspension or tension hardware, when specified
- Substation connection assemblies
Components
U-Shaped Body
The main U-shaped member transfers mechanical load between the connected components. Its internal width, body diameter and effective length must match the adjoining hardware.
Cross Bolt
The transverse bolt passes through both ends of the U-shaped body and provides the removable connection point. Bolt diameter, material grade and thread specification must be confirmed for each model.
Nut and Washers
The nut secures the cross bolt, while the washers distribute contact pressure and help maintain the correct assembly position.
Retaining Cotter Pin
The cotter pin is installed through the drilled end of the bolt to reduce the risk of the nut loosening and the connection separating during service.
Material and Manufacturing
The main body is manufactured from load-bearing steel suitable for the required mechanical load. Depending on the approved product design, forming, forging and machining processes may be used to produce the body, bolt and associated components.
The photograph alone cannot confirm the exact steel grade or manufacturing route. These details should be stated on the approved drawing or material certificate when they are required by the project.
Hot-Dip Galvanized Finish
The steel components are hot-dip galvanized to provide corrosion protection for outdoor transmission, distribution and substation environments. The required coating standard and minimum coating thickness should be specified before production.
Hot-dip galvanizing may be specified according to ISO 1461, GB/T 13912 or the applicable utility specification. The retaining cotter pin may use stainless steel or another corrosion-resistant material according to the product drawing.
Selection Guidance
- Confirm the specified failure load of the complete hardware string.
- Select a shackle model with compatible body and bolt dimensions.
- Check the thickness and hole diameter of the adjoining fitting.
- Verify that the connection can rotate without interference.
- Confirm the required steel grade and manufacturing process.
- Specify the galvanizing standard and coating requirement.
- Check the orientation and retaining method shown on the approved assembly drawing.
Installation Guidance
- Inspect the shackle body, bolt, nut, washers and cotter pin before installation.
- Remove the cotter pin, nut and cross bolt.
- Position the adjoining fitting between the two ends of the U-shaped body.
- Insert the cross bolt through all aligned connection holes.
- Install the washers and tighten the nut according to the approved procedure.
- Insert and correctly open the retaining cotter pin.
- Confirm that the connection can articulate without binding.
- Inspect the completed assembly before loading.
Quality Inspection
- Raw-material certificate verification
- Model and dimensional inspection
- Body surface inspection for cracks, laps and harmful deformation
- Bolt, nut and thread-fit inspection
- Cotter-pin hole and retention inspection
- Hot-dip galvanized coating appearance and thickness inspection
- Mechanical specified-failure-load testing when required
- Assembly compatibility and movement inspection
- Marking, quantity and packaging inspection
Reference Standards
- IEC 61284 – Overhead lines: requirements and tests for fittings
- GB/T 2315-2017 – Specified failure load series and coupling dimensions for electric power fittings
- ISO 1461:2022 – Hot-dip galvanized coatings on fabricated iron and steel articles
- GB/T 13912 – Metallic coatings: hot-dip galvanized coatings on fabricated iron and steel articles
- Applicable utility drawings and project technical specifications
Reference to a standard does not constitute certification. Compliance must be supported by inspection and test documents for the exact product model supplied.
Ordering Information
Please provide the following information when requesting a quotation:
- Required U-series model
- Specified mechanical failure load
- Internal width and effective length
- Body and cross-bolt diameters
- Adjoining fitting thickness and hole diameter
- Steel material and fastener grade
- Hot-dip galvanizing standard and coating requirement
- Applicable drawing or project standard
- Required inspection and test documents
- Quantity, marking and packaging requirements
Frequently Asked Questions
What is a U-type shackle used for?
It is used as a load-bearing connecting fitting between compatible components in an overhead-line insulator or hardware assembly.
What is the difference between U-7 and U-10?
They belong to different dimensional and mechanical load classes. A commonly referenced load class is 70 kN for U-7 and 100 kN for U-10, but the supplied product must be verified using the approved drawing and test report.
Can it be used with suspension and tension hardware?
Yes, provided that the coupling dimensions, articulation requirements and mechanical load class match the approved hardware-string design.
Is this a lifting shackle?
No. This product is designed as an electric power line fitting and must not be marketed as general lifting or rigging hardware without separate certification.
Can customized sizes be manufactured?
Yes. Dimensions, load class, steel material, coating, component marking and packaging can be produced according to an approved customer drawing.
