Narrow-Track Agricultural Tractors: A Survey on the Load of the Hand-Operated Foldable Rollbar.

Abstract

To protect the driver in case of a tractor overturn, narrow-track tractors (used in vineyards and orchards) can be equipped with a rollover protective structure (ROPS) consisting of a two-pillar front-mounted foldable rollbar. The transition from the horizontal (rest) to the vertical (protection) position of this ROPS is performed manually by the driver. In addition to the time spent performing this task many times each day, a moderate physical load is required, given that these rollbars often have a mass of some tens of kilograms. In practice, neglect and poor attention to safety lead to the foldable rollbar remaining continuously in the rest position rather than being moved to the vertical (protection) position. Several rollover accidents have been fatal for the driver because the tractor, although equipped with a two-pillar front-mounted ROPS, had the rollbar in the horizontal position at the time of the event, thus assuring no protection to the driver. This issue is quite serious. To remove at least one of the problems for the proper management of this type of ROPS, the OECD has recently updated its Code 6 by introducing an optional test addressing the manual handling of front-mounted rollbars, providing a maximum load of 100 N. Several tests were conducted on new rollbars to ascertain the accuracy of this limit. The 100 N value was generally exceeded, which is cause for criticism. Indeed, a more appropriate reference for manual handling in this case would be the higher loads (up to 250 N) already provided by other standards for non-continuous tasks.