GB/T 21956.1-2024 Active

This document specifies the static and dynamic strength test procedures for front-mounted rollover protection structures of narrow-track wheeled tractors in the agricultural and forestry fields, defines the shelter zone and establishes the acceptance criteria for front-mounted fixed or foldable double-column rollover protection structures (including all associated rear rigid components), and prescribes optional test procedures for seat belt anchorage devices and folding forces of front-mounted rollover protection structures. This document applies to tractors with the following characteristics: — The ground clearance between the lowest points of the front and rear axles does not exceed 600 mm (excluding the lowest point of the differential); — For tractors with maximum-sized tires on the front or rear wheels, regardless of whether the wheelbase is fixed or adjustable, the minimum wheelbase of the tractor does not exceed 1,150 mm; — The tractor has a counterweight mass (including the rollover protection structure and the manufacturer's recommended maximum tires) greater than 400 kg and less than 3,500 kg; — It is equipped with a double-column rollover protection structure that can only be installed in front of the seat reference point (SIP); — The mass ratio (mr) does not exceed 1.75.