Coupling Plate: Weight Capacity Up to 36,000 kg

Component Specifications

Definition

The coupling plate is a precisely engineered metal plate that serves as the mounting interface between the fifth wheel coupling assembly and the tractor chassis. It distributes vertical, horizontal, and torsional loads from the trailer through the coupling mechanism to the tractor frame, maintaining alignment and structural integrity under dynamic operating conditions. This component must withstand significant shear forces, bending moments, and fatigue stresses while providing a stable foundation for the kingpin engagement system.

Working Principle

The coupling plate functions as a load-transfer interface that converts trailer forces into manageable stresses on the tractor frame. It provides a rigid mounting surface for the fifth wheel assembly while allowing controlled flexure to absorb operational shocks and vibrations. The plate's geometry and bolt pattern ensure proper weight distribution and prevent stress concentration points that could lead to structural failure.

Materials

High-strength low-alloy steel (HSLA) grades such as ASTM A572 or equivalent, typically with yield strength of 345-550 MPa. Heat-treated alloy steels may be used for heavy-duty applications. Surface treatments include hot-dip galvanizing, zinc plating, or powder coating for corrosion resistance.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Thickness	12-25 mm
Bolt Pattern	SAE J700 compliant
Mounting Holes	8-12 holes (M16-M24)
Surface Finish	Ra 3.2-6.3 μm
Weight Capacity	Up to 36,000 kg

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 8717, SAE J700, DIN 74080

Parent Products

This component is used in the following industrial products

Fifth Wheel Coupling

A specialized coupling mechanism that connects a terminal tractor to semi-trailers, allowing articulation and load transfer.

View Product Details

Engineering Analysis

Risks & Mitigation

Fatigue cracking under cyclic loading
Corrosion-induced weakening
Bolt hole elongation from vibration
Improper installation causing stress concentrations

FMEA Triads

Trigger: Material fatigue from repeated loading cycles
Failure: Crack propagation leading to structural failure
Mitigation: Regular non-destructive testing (NDT), proper material selection with adequate fatigue strength, and design optimization to reduce stress concentrations

Trigger: Corrosion due to environmental exposure
Failure: Reduced cross-sectional area and compromised structural integrity
Mitigation: Protective coatings, regular maintenance, and use of corrosion-resistant materials or treatments

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

±0.5 mm for hole positioning, ±0.2 mm for plate flatness

Test Method

Ultrasonic testing for material integrity, dye penetrant inspection for surface cracks, load testing to 150% of rated capacity

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Coupling Plate

1 company lists this product among what they make. Company figures are quoted from each company's own website; every card states where the relationship came from.

Jiangyin Xinyu Forging Co., Ltd.

Jiangyin, Jiangsu, CN

Founded 2004

ISO 9001 API Spec 20B TÜV PED

Also makes: Forged Steel Flange, Steel Forging

Listed on the company's own website · profile compiled by CNFX from public sources

Listed there as: “Coupling Plate”
View source page ↗ xinyuforging.com · checked 2026-08-26

View profile Send enquiry

Manufacturer listings support early research and capability understanding. They are not certification, ranking, or transaction guarantees.

Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

What is the primary function of a coupling plate in fifth wheel systems?

The coupling plate serves as the structural interface that transfers loads from the trailer through the fifth wheel mechanism to the tractor frame, ensuring secure attachment and proper weight distribution.

How often should coupling plates be inspected for wear or damage?

Coupling plates should be visually inspected before each trip and undergo detailed inspection every 6 months or 50,000 km, with particular attention to crack formation, bolt hole deformation, and corrosion.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Coupling Plate