Paul Ayers, Farzaneh Khorsandi 2017-10-25 01:50:55
Progress in ROPS Technology Agricultural tractors have played a critical role in agricultural mechanization. Tractors have high clearance, varied external forces, and often operate on steep or unstable terrain. Because of these conditions, tractors are prone to instability and rollovers. As tractor usage increased, overturn incidents and fatalities also increased. By 1955, an estimated 1,500 tractor rollover fatalities were occurring annually. To combat this situation, agricultural engineers worked to develop rollover protective structures, or ROPS. One of the first ROPS (called the “tractor driver safety frame”) was successfully tested by the Department of Agricultural Engineering at the University of California, Davis, in 1956. In 1960, U.S. Patent No. 3,455,598 was issued to Deere and Co. for a tractor roll bar and canopy. This patent was shared without royalties. In 1962, the ASAE Rollbar Symposium was held at the Winter meeting, and by 1966, John Deere offered ROPS on all new tractors, but they could be deducted. In 1967, ASAE established some of the initial engineering performance standards for ROPS design and testing. ROPS are designed to protect tractor operators in the event of a rollover by absorbing energy while providing a protected clearance zone for the operator. A ROPS is considered a protection system because it includes the use of a seat belt, and ROPS standards were developed to ensure uniformity of production. ASABE and members of the MS 23/2/2 ROPS committee (previously PM 23/2/2) have been instrumental in maintaining the engineering performance standards to make ROPS an effective method for reducing the frequency and severity of injury during tractor rollovers. To recognize its impact on agricultural safety, in 1986 ASABE dedicated the rollover protective structure as the 21st Historic Landmark. However, tractor overturns were still resulting in high numbers of fatalities, as many tractors did not have ROPS, and new tractors were still being sold without ROPS. In 1975, OSHA attempted to address this problem by requiring ROPS on all agricultural tractors larger than 20 hp and manufactured after October 25, 1976. However, this regulation (29 CR 1928) could only be enforced on farms with more than eleven employees, limiting its impact. Recently, some states have introduced regulations requiring more widespread use of ROPS. In 1985, ASAE Standard S318.8, Safety for Agricultural Equipment, required that ROPS be provided on all new tractors and meet appropriate engineering standards. North American tractor manufacturers agreed to sell all new tractors with ROPS. While ROPS were previously an option, this standard ensured that all new tractors went out the door with a ROPS installed. In the 1990s, tractor manufacturers (including John Deere, AGCO, Case IH, and Kubota) again worked together to promote ROPS usage and make ROPS available at cost to encourage ROPS retrofits. In 1990, a guide to tractor rollbars and other rollover protective structures was developed and provided a useful tool for identifying manufacturers that would provide retrofit ROPS for specific tractors. The guide has been updated frequently and is currently available online at: http://rops.ca.uky.edu. While these actions significantly improved the number of tractors with ROPS, there were still many tractors without ROPS, and tractor rollovers continued to be the leading cause of agricultural fatalities. In 1990, the National Institute of Occupations Safety and Health (NIOSH) launched an Agricultural Safety and Health Program, and the 1991 Surgeon General’s Conference on Agricultural Safety and Health recognized tractor rollover fatalities as “an occupational obscenity.” The NIOSH-sponsored Tractor Death and Injury Prevention Workshop was held in Pittsburgh in 2003 to address the large number of tractor-related fatalities. The need for tractor ROPS retrofits was identified, and intervention, education, incentives, and regulation were considered. Although regulation (such as requiring ROPS on all tractors) was shown to be effective in some European countries, this regulation met stiff political resistance in the U.S. A NIOSH-sponsored National Tractor Safety Initiative (2005- 2007) looked at further efforts to reduce tractor fatalities. In 2014, the National Tractor Safety Coalition was formed and identified tractor rollovers and ROPS retrofits as its leading priority. A National ROPS Rebate Program (NRRP) was initiated, modeled after several successful state ROPS rebate programs, as originated in 2006 by the New York Center for Agricultural Medicine and Health (NYCAMH). A similar, smaller state program was launched by the Virginia Farm Bureau in 1995. These programs provide financial incentives for tractor owners to retrofit ROPS on existing tractors. The NRRP was officially launched in June 2017 and has the support of U.S. government agencies, farm groups, ROPS and tractor manufacturers, academia, and other interested groups, with NIOSH providing the administrative support. Participation by tractor owners in the NRRP is voluntary, and the rebate funds are provided by state government contributions and private donations. ROPS rebates are approximately 70% of the cost of a retrofit, up to a capped amount. Program details are available at: www.ROPSr4u.com, and an example of a ROPS retrofit resulting from the NRRP is shown on the opposite page. In a separate effort to reduce the cost of ROPS, NIOSH developed the Cost-effective ROPS (CROPS) program, which provides construction specifications for low-cost ROPS that meet the appropriate ROPS performance standards. These efforts have led to a reduction in agricultural tractor rollover fatalities, as shown in the above graph. Hopefully, in future years, these numbers will continue to decline as the percentage of tractors without ROPS decreases. However, new potential concerns are on the horizon. When ROPS are installed, they increase the vertical height of the tractor, making vertical clearance an issue in orchards and when entering low-clearance structures. Although foldable ROPS, developed in the 1990s, allow lowering and raising of the ROPS when needed, there is a tendency for a tractor operator to leave the ROPS down after lowering it. Some say this is a step backward, as we are seeing an increase in tractor rollover fatalities with the ROPS folded down. NIOSH has attempted to address this problem with the development of an automatically deployable ROPS (AutoROPS). The AutoROPS remains in the down position until an impending overturn is detected by stability sensors. The AutoROPS then deploys quickly and locks in place before the overturn occurs, thereby protecting the tractor operator. Although the prototype proved effective, a reliable commercially available unit was never adopted. In addition, lift-assist devices for foldable ROPS are being developed to encourage tractor operators to raise their foldable ROPS to the upright position. Efforts are also underway to provide real-time stability information to operators to help them avoid unstable operating conditions. In this area and others, ASABE members have long addressed the safety needs of agricultural production, and they will continue to do so. ASABE member Paul Ayers, P.E., Professor, Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, USA, firstname.lastname@example.org. ASABE member Farzaneh Khorsandi, Assistant Specialist in Cooperative Extension, University of California-Davis, USA, email@example.com
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