The driver’s protection in case of self-propelled machinery roll-over

Despite a real risk of overturning, for the Self-Propelled agricultural Machinery (SPM) the ROPS approach to protect the driver is rather recent. Due to the several SPM categories available on the market, characterized by very different mass, dimension and working functions, the fitting of a ROPS and consequently the check of its strength is complicated. The SPM could be preliminarily divided into at least two categories: - large SPM: combine, forage, potato, sugar-beet and grape harvesters; sprayer; etc.; - small SPM: ride-on tractor, mower, comb side-delivery rake, etc. The most followed approach at present is to define preliminarily the overturning behaviour of the SPM, considering its longitudinal and lateral stability; if a real risk is detected, in order to minimize the likelihood of driver's injury the manufacturer often decides to install a ROPS. The consequent need is to provide some relevant test criteria. Sprayers among large SPM, and comb side-delivery rake among small SPM were the machine types on which the ROPS were tested, adopting in both cases the procedure provided by Code 4 issued by the Organization for Economic and Cooperation Development (OECD), dedicated to ROPS fitted on conventional agricultural and forestry tractors. On the sprayer having a mass of 4950 kg was fitted a closed cab, while on the comb side-delivery rake having a mass of 690 kg was applied a 3-pillars frame. The response was positive in both tests, so indicating a general suitability of OECD Code 4 to assure a ROPS good driver’s protection level in case of overturning. On the other hand, to ascertain more in detail the roll-over behaviour of the SPM, some further questions need to be deeply examined, such as the driver’s place location, the height of the centre of gravity from the ground in different machine configurations (i.e. with product tanks empty or full), the external silhouette, the axles mass distribution of the laden/unladen machine, etc.