E2D-ROPS: Development and tests of an automatically deployable, in height and width, front-mounted ROPS for narrow-track tractors

The main cause of death in agriculture has been the overturning of tractors lacking ROPS. Front mounted rollbars are usually foldable to be used in low clearance situations. Most fatal accidents involving tractors with foldable ROPS have occurred because, at the moment of the overturn, the ROPS was at the lower position. In this research, an automatically deployable front-mounted ROPS for narrow tractors, using airbag inflators able to increase simultaneously the height and the upper width of the ROPS, was designed, constructed and tested. The double change of the ROPS geometry reduces the continuous rolling risk, increases the safety zone in a lateral direction, and allows the ROPS height, the bending moments at critical sections and the ROPS beams sections to be reduced. This ROPS has been named ‘Ejectable in Two Dimensions ROPS’ (E2D-ROPS). Using an FE computer program, the necessary sections for E2D-ROPS to be mounted in two tractor models, ensuring a positive result for Code 6 tests, were calculated using different reference masses. An E2D-ROPS prototype was designed, constructed and mounted on a John Deere 60 C tractor. The tractor was tilted and when its lateral inclination reached 60°, an inclinometer activated two airbag inflators, located into its inclined beams, which deployed and locked the E2D-ROPS at its operative position in 102 ms. The E2D-ROPS was tested, using only one airbag inflator located into its transverse beam and was deployed and locked in 312 ms. The system works correctly because these times are lower than the overturn time.