ISO 26402:2008

Overview

ISO 26402:2008, titled Agricultural Vehicles - Steering Systems for Agricultural Trailers - Interface for Articulated Steering Device of Semi-Mounted Trailers, is an international standard published by the International Organization for Standardization (ISO). This standard specifies the mechanical interface dimensions, clearance zones, and maximum permissible forces at the connection point between tractors and semi-mounted agricultural trailers equipped with articulated steering devices.

The standard is designed exclusively for use alongside ISO 24347, which defines the specifications for an 80 mm nominal diameter ball-type mechanical coupling device. It does not cover the verification of mechanical strength nor the detailed design of the articulated steering device itself but focuses on ensuring compatibility and safety at the interface for agricultural applications.

Key Topics

• Interface Dimensions: ISO 26402:2008 defines precise dimensions and positional tolerances for connecting points on both tractors and semi-mounted trailers to ensure mechanical compatibility and horizontal and vertical alignment with the tractor's rear axle.
• Articulated Steering Connection: The standard addresses the interface for articulated steering devices that link the trailer’s steered wheels to the towing tractor’s movement, enabling safe and effective maneuverability.
• Force Limits: Maximum permissible forces are specified to not exceed 20 kN in the direction of the steering rod connection, with the recommendation of force-limiting means such as hydraulic systems where necessary.
• Clearance Zones: Detailed clearance zones are provided to prevent mechanical interference during operation, safeguarding tractor and trailer components.
• Safety Features: Mechanical means are required to prevent unintentional disconnection of connecting points, and connectors should be detachable if they interfere with the movement of tractor components such as three-point linkages.
• Compatibility: The interface must be compatible specifically with a 50 mm ball-type connector on the tractor side and an 80 mm ball-type coupling on the trailer side as per ISO 24347 and ISO 1103.
• Angular Movement Compliance: Requirements for pitch, yaw, and roll angles for the mechanical joint are established to ensure adequate articulation without mechanical contact or damage.

Applications

ISO 26402:2008 is essential for manufacturers, designers, and engineers involved in the manufacture and assembly of agricultural machinery, specifically semi-mounted trailers with articulated steering systems. Key applications include:

• Agricultural Machinery Manufacturing: Enables the design of steering interfaces that comply internationally, ensuring interchangeability and safety.
• Trailer Design: Assists trailer manufacturers in meeting safety and compatibility requirements for articulated steering devices.
• Farm Equipment Compatibility: Supports improved compatibility between tractors and semi-mounted trailers, preventing unsafe detachment or mechanical failure.
• Maintenance and Safety Checks: Provides technical specifications useful for maintenance teams to verify correct installation and operational parameters concerning forces and clearance.
• Equipment Certification: Serves as a reference standard for certifying compliance in agricultural vehicle steering systems and interface designs.

Related Standards

To fully comply and understand the scope of ISO 26402:2008, the following related ISO standards should be considered:

• ISO 24347:2005 - Agricultural Vehicles - Mechanical Connections - Ball-Type Coupling Device (80 mm): Defines the ball-type coupling device to which ISO 26402 applies.
• ISO 1103:2007 - Road Vehicles - Coupling Balls for Caravans and Light Trailers - Dimensions: Provides dimensions for the 50 mm ball-type connecting points used on the tractor side.
• ISO 730 - Agricultural Wheeled Tractors – Rear-Mounted Three-Point Linkage: Relevant for understanding the tractor’s linkage interface and movement requirements.
• ISO 17900:2002 - Agricultural Trailers – Balanced and Semi-Mounted Trailers – Determination of Payload and Loads: Details technical aspects related to payload and loading, complementing steering interface safety.

Keywords: ISO 26402:2008, agricultural vehicles, articulated steering device, semi-mounted trailers, tractor-trailer interface, steering system standard, 80 mm ball-type coupling, agricultural trailer safety, machinery compatibility, agricultural vehicle standards.