Hot-Dip Galvanized PD-Type Single-Plate Parallel Clevis
The PD-type parallel clevis is a single-plate mechanical link fitting used in overhead transmission lines, distribution lines and substation connection assemblies. It connects two compatible line fittings, extends the installation distance and helps coordinate the connection between single-plate and double-plate components.
The product features a flat elongated body with one circular connection hole at each end. The rounded ends distribute mechanical stress around the pin holes, while the reinforced center section provides strength without unnecessarily increasing the overall dimensions.
PD-type clevis links are commonly installed between yoke plates, suspension clamps, strain clamps, U-type clevises, parallel clevises and other insulator-string fittings. Hole diameter, plate thickness, center distance and mechanical-strength class must match the adjoining hardware and the approved assembly drawing.
Model-identification notice: The smaller product shown in the photographs is marked PD-7. The complete marking on the larger product is not sufficiently clear to confirm its exact model. The larger product must be measured before it is published as PD-16, PD-20 or another specification.
Key Features
- Single-plate two-hole construction
- Designed for parallel connection and assembly extension
- Rounded ends around both connection holes
- Compact structure for overhead-line hardware assemblies
- Multiple hole diameters and mechanical-strength classes available
- Suitable for suspension and tension insulator strings
- Galvanized surface for outdoor corrosion protection
- Model and load marking can be cast, forged or stamped on the body
- Custom dimensions available according to approved drawings
Typical Technical Specifications
| Product Type | PD-Type Single-Plate Parallel Clevis |
|---|---|
| Alternative Names | PD Clevis Link Plate / Parallel Link Plate / Extension Clevis |
| Structure | Single plate with two connection holes |
| Representative Models | PD-7, PD-10, PD-12, PD-16 and PD-20 |
| Representative Load Classes | 70, 100, 120, 160 and 200 kN |
| Material | Carbon steel, forged steel or cast steel according to the approved specification |
| Surface Finish | Hot-dip galvanized |
| Connection Method | Pin or bolt connection through two end holes |
| Application | Overhead-line suspension, tension and insulator-string assemblies |
| Customization | Hole diameter, center distance, plate thickness, load class, marking and coating |
The model range and load classes above are representative product-family data. Exact ratings must be supported by the drawing and mechanical test report for the supplied model.
Representative Model Selection
| Model | Hole Diameter | Overall Length | Plate Thickness | Hole Center Distance | Nominal Failure Load |
|---|---|---|---|---|---|
| PD-7 | 18 mm | 70 mm | 16 mm | 40 mm | 70 kN |
| PD-10 | 20 mm | 80 mm | 16 mm | 45 mm | 100 kN |
| PD-12 | 24 mm | 100 mm | 16 mm | 60 mm | 120 kN |
| PD-16 | 26 mm | 100 mm | 18 mm | 60 mm | 160 kN |
| PD-20 | 30 mm | 120 mm | 26 mm | 72 mm | 200 kN |
These are representative selection values found in commonly published PD-series tables. Dimensions may differ between design systems and manufacturers. Always use the final approved drawing for procurement and installation.
Function in Line-Hardware Assemblies
The PD-type clevis is installed where a short, single-plate link is needed between two compatible fittings. It can increase the distance between assembly components and provide the required clearance for movement or installation.
Unlike a Z-type right-angle clevis, the PD-type plate does not normally change the connection direction by 90 degrees. Unlike a P-type parallel clevis, it is a single solid plate and is normally supplied without two side plates or integral connection bolts.
Materials and Manufacturing
PD-type link plates may be manufactured from forged steel, cast steel or machined and formed steel according to the product design. The photographs show a reinforced, moulded body profile, but the manufacturing process and material grade cannot be determined from appearance alone.
The connection-hole surfaces must be smooth and free from cracks, sharp burrs or defects that could produce concentrated stress on the adjoining pins. Material grade, heat treatment and dimensional tolerances must be confirmed in the approved production drawing.
Hot-Dip Galvanized Finish
Steel components are normally hot-dip galvanized to provide corrosion protection for outdoor overhead-line environments. The galvanized coating should cover the exposed surfaces evenly without interfering with the connection holes or assembly clearances.
Coating requirements may be specified according to ISO 1461, GB/T 13912 or the applicable utility standard. The zinc-coating thickness must be verified by the agreed inspection method.
Applications
- Overhead transmission-line insulator strings
- Distribution-line suspension assemblies
- Strain and dead-end assemblies
- Connection between single-plate and clevis-type fittings
- Yoke-plate and link-fitting assemblies
- Suspension-clamp connection systems
- Substation mechanical connection assemblies
- ADSS and OPGW hardware assemblies when specified by the approved design
Installation Guidance
- Confirm the required PD model and nominal mechanical load.
- Check the hole diameter and center distance against the approved drawing.
- Confirm that the adjoining clevis opening can receive the plate thickness.
- Inspect the product for cracks, deformation, damaged holes or coating defects.
- Insert the plate fully into the adjoining clevis fitting.
- Install the correct pin or bolt through each connection hole.
- Install all nuts, washers and retaining pins required by the assembly drawing.
- Confirm that the assembly can articulate without binding or edge loading.
- Inspect the completed assembly before the line is tensioned or energized.
Quality Inspection
- Raw-material and manufacturing-record inspection
- Overall length and plate-thickness inspection
- Hole diameter and center-distance inspection
- Surface inspection for cracks, porosity and sharp edges
- Model and load-marking inspection
- Hot-dip galvanized coating appearance and thickness inspection
- Mechanical tensile or failure-load testing when specified
- Fit verification with the corresponding pins and clevis fittings
- Packaging and traceability inspection
Reference Standards
- IEC 61284:1997 – Overhead lines: requirements and tests for fittings
- DL/T 759-2023 – Link fittings
- GB/T 2314-2008 – General technical requirements for electric power fittings
- ISO 1461:2022 – Hot-dip galvanized coatings on fabricated iron and steel articles
- GB/T 13912-2020 – Hot-dip galvanized coatings on fabricated iron and steel articles
- Applicable utility specifications and approved assembly drawings
Reference to a standard does not constitute certification. Compliance must be supported by dimensional inspection records and mechanical test reports for the exact product model.
Ordering Information
Please provide the following information when requesting a quotation:
- Required PD model
- Nominal mechanical load
- Hole diameter
- Hole center-to-center distance
- Plate thickness and overall dimensions
- Required steel or casting material grade
- Hot-dip galvanizing requirement
- Required product marking
- Applicable standard and inspection documents
- Order quantity and packaging requirements
Frequently Asked Questions
Is this a P-type or PD-type parallel clevis?
It is a PD-type single-plate parallel clevis. A conventional P-type clevis normally consists of two parallel side plates and two connection pins or bolts.
What does the number in PD-7 mean?
In commonly used Chinese line-fitting model systems, the number normally corresponds to the nominal mechanical-load grade. PD-7 is generally associated with a 70 kN nominal failure-load class, but the exact rating must be supported by the applicable drawing and test report.
Are connection pins included?
The PD plate itself is normally supplied as a separate link fitting. Pins or bolts may belong to the adjoining fittings or be supplied separately according to the agreed packing list.
Can PD-7 be replaced with PD-10?
Not directly. The two models may have different hole diameters, overall lengths, center distances and mechanical-load ratings. Compatibility with all adjoining components must be checked.
Can custom dimensions be manufactured?
Yes. Custom hole size, center distance, body dimensions, marking and mechanical rating can be produced according to an approved drawing and verification plan.
