Drawbeams, drawbar couplings, drawbar eyes, and drawbars are products that are collectively called coupling products. For coupling products to be used in a truck combination for road transport the coupling product must be type-approved according to UNECE R55.
According to the regulations, the product must undergo mechanical tests as part of the approval process to ensure its performance and fatigue properties. This mechanical testing is carried out by, for example, dynamic longitudinal tests or a combination of longitudinal and vertical tests. In the dynamic test, 2 million cycles are run, after which the product material must not show any cracks. There is an exemption in the regulations for simple designs that do not require any form of mechanical testing, which can instead be approved by means of calculations. Whether a product constitutes a simple design is determined by the approval authority. This exemption for simple designs is typically used very restrictively by the approval authority, but there are coupling products like drawbeams, drawbar eyes and drawbars on the market that have been approved by calculation.
Mechanical testing and calculation
Another part of the regulations describes that production of the coupling product must be monitored over time. This is done through follow-up inspections of materials and new mechanical testing of the product. Referred to as Conformity of Production (COP) which shall be performed according to a defined scheme. For products approved by calculation, mechanical testing is not carried out during the approval process nor through COP.
Ringfeder is investing in and continuously developing its own testing capacity to carry out mechanical testing to ensure the highest traffic safety on our roads. Keep in mind that the products are the only link between the towing and towed vehicles!
This is a testa of one our drawbars.
Stricter follow-up inspections by the approval authority have shown that there are doubts about products approved by calculations, and the authorities have now clarified how they will work in the future. A product with a simple design may continue to be approved by calculation, but the product must also pass a mechanical test at follow-up inspection (COP).
Dynamic testing confirms or provides input for the calculations and process implementation.
