STUDIO E VALIDAZIONE DI SOLUZIONI INNOVATIVE IN TEMA DI STRUTTURE DI PROTEZIONE IN CASO DI RIBALTAMENTO DEI TRATTORI AGRICOLI

New solutions to (ideally remove), but practically reduce, occupational hazard factors on agricultural machines are needed. Self-propelled machines and tractors frequently determine serious accidents, mainly due to overturning: 10 % of all the accidents and 35 % of those fatal is due to the tractor. To protect conveniently the driver from serious injuries in case of overturning, both a ROPS (Roll Over Protective Structure) and a seat belt are needed. Nevertheless, the application of a ROPS involves some limits: sometime working in orchards and vineyards or entering into low farm buildings could be difficult and unconfortable. Possible solutions are the fitting of a front mounted tiltable roll-bar (that can be lowered in case of special operations) or a self-deployable protective structure. To increase the fitting of a ROPS on some tractor categories (i.e. used tracklaying tractors) where a diffused lack is verified, a detailed statistics was carried out to find the most popular models still in use in Italy; for them, dedicated ROPS were designed and manufactured and then their technical validity was ascertained through specific tests, following the OECD Code 8. The structural deterioration with age of tractor ROPS was a further item investigated: a survey on the italian wheeled tractors fleet trend from 1982 to 1998 was realized, by ascertaining on the most diffused tractor models the main structural members condition, checking in particular if critical working conditions (corrosion, vibrations, etc) could have jeopardized the ROPS mechanical resistance in case of overturning. Some studies to validate innovative solutions are still in progress. On the matter, it should be considered what follows: - the application of active safety concept is not applicable; all the solutions carried out refer to a passive safety; - to solve problems about a not diligent application and use of safety systems, automatic or semiautomatic devices devoted to fold and unfold the roll-bar or AutoROPS or airbag should be preferred; - the extension of the passive safety concept to self-propelled machines (apart from tractors) and other operators different from the driver should be a must to be seriously considered as soon as possible.