DB Type Multi-Hole Adjusting Plate for Insulator Strings
The DB type multi-hole adjusting plate is a mechanical connection fitting designed for overhead transmission and distribution-line insulator strings. By selecting different connection holes, installers can change the effective length of the fitting string in fixed increments and obtain the required assembly position.
The product uses two parallel steel plates connected by bolts or pins. Multiple intermediate holes provide selectable connection positions, while the extended end eye connects to compatible link fittings, yoke plates, clevis fittings or other components specified in the approved string-assembly drawing.
DB type adjusting plates are normally manufactured from carbon steel or high-strength steel and protected by hot-dip galvanizing for outdoor service. Plate dimensions, hole spacing, hardware diameter and mechanical strength must match the adjoining fittings and the required design load.
Important: This product provides stepped adjustment through individual holes. It is not a continuously sliding adjustment device. The selected hole must be secured with the specified bolt or pin and locking component.
Key Features
- Double parallel-plate construction
- Multiple holes for stepped connection-length adjustment
- Compatible with insulator strings and overhead-line link fittings
- Bolted or pinned assembly for installation and maintenance
- Cotter pins or equivalent locking components help prevent loosening
- Hot-dip galvanized steel construction for outdoor environments
- Hole diameter, spacing and plate dimensions can be customized
- Available for different mechanical load classes
Typical Technical Specifications
| Product Type | DB Type Adjusting Plate / Multi-Hole Link Plate |
|---|---|
| Structure | Double parallel steel plates |
| Adjustment Method | Stepped adjustment through selectable connection holes |
| Adjustment Holes | Three intermediate holes shown; other configurations available |
| Base Material | Carbon steel or high-strength steel, subject to approved drawing |
| Surface Finish | Hot-dip galvanized |
| Connection Hardware | Steel bolts or pins, nuts, washers and cotter pins |
| Installation | Bolted or pinned mechanical connection |
| Application | Insulator strings, suspension assemblies, tension assemblies and overhead-line fitting strings |
| Dimensions | According to model, project drawing and adjoining fitting interfaces |
| Mechanical Load | To be confirmed by model, drawing and mechanical test report |
| Customization | Plate length, thickness, hole diameter, hole spacing, hardware, coating, marking and packaging |
The specifications shown are general product characteristics. Final dimensions, tolerances and rated mechanical performance must be confirmed using the approved drawing and test documentation.
Structure and Adjustment Principle
The adjusting plate consists of two parallel plates that form a double-shear connection around the adjoining fitting. Several holes are arranged along the plate body. Moving the connecting bolt or pin from one hole to another changes the effective connection length in fixed increments.
This stepped adjustment can assist with insulator-string length matching, assembly alignment and the positioning of associated line fittings. The selected connection position must follow the approved overhead-line string drawing.
Applications
- Suspension insulator-string assemblies
- Tension and dead-end insulator strings
- Overhead transmission-line fitting strings
- Distribution-line hardware assemblies
- Substation connection fittings
- Connections involving yoke plates, clevis fittings and link fittings
Materials and Surface Protection
The plates are normally manufactured from carbon steel or another specified structural-steel grade. Connection bolts, pins, nuts and washers must provide the mechanical capacity required by the complete assembly.
Hot-dip galvanizing protects the steel components against atmospheric corrosion. Zinc-coating thickness, adhesion, appearance and test method should be specified in the purchase requirements. Damaged coating areas must be repaired using an approved method.
Selection Requirements
- Required mechanical load or specified failure load
- Number of adjustment positions
- Hole diameter and center-to-center spacing
- Total plate length, width and thickness
- Dimensions of the adjoining fittings
- Bolt or pin diameter and locking arrangement
- Required adjustment increment
- Galvanizing and corrosion-protection requirements
The nominal system voltage alone is not sufficient for model selection. Mechanical load, interface dimensions and the approved insulator-string configuration are the primary selection parameters.
Installation Guidance
- Verify the model, dimensions and mechanical rating before installation.
- Check that the plate holes and adjoining fittings are free from deformation or damage.
- Select the connection hole specified on the approved assembly drawing.
- Insert the correct bolt or pin through both plates and the mating fitting.
- Install the nut, washer and cotter pin or other specified locking component.
- Confirm that the connection can articulate as required without interference.
- Inspect the assembly after loading for incorrect positioning, deformation or loose hardware.
Quality Inspection
- Raw-material and material-certificate verification
- Plate length, width and thickness inspection
- Hole diameter and hole-spacing inspection
- Bolt, pin, nut and locking-component inspection
- Hot-dip galvanized coating inspection
- Assembly and interface-fit inspection
- Mechanical load or failure-load testing when specified
- Marking, quantity and packaging inspection
Reference Standards
- DL/T 759-2023 – Link fittings
- IEC 61284:1997 – Overhead lines: requirements and tests for fittings, when applicable
- ISO 1461:2022 – Hot-dip galvanized coatings on fabricated iron and steel articles
- Applicable utility drawings and customer technical specifications
Reference to a standard does not constitute certification. Compliance claims must be supported by inspection or test documentation for the exact product model.
Ordering Information
Please provide the following information when requesting a quotation:
- DB model or approved product drawing
- Required mechanical load class
- Plate length, width and thickness
- Hole quantity, diameter and spacing
- Required adjustment range and increment
- Bolt or pin dimensions and material grade
- Surface-treatment and zinc-coating requirements
- Required standard and test documentation
- Product marking, quantity and packaging
Frequently Asked Questions
Is this product a yoke plate?
No. Its primary function is to adjust the effective connection length through selectable holes. It may be connected to a yoke plate as part of a complete fitting string.
Does it provide continuous adjustment?
No. The connection length is adjusted in fixed steps by selecting one of the available holes.
Can it be used in both suspension and tension strings?
Yes, when the dimensions, interface type and mechanical rating meet the requirements of the approved string-assembly design.
Are the bolts and cotter pins included?
They can be supplied as part of the assembly. The exact hardware and supply scope must be stated in the quotation and packing list.
How is the correct model selected?
Selection is based primarily on mechanical load, hole dimensions, connection spacing, adjoining fittings and the approved line-hardware drawing.
