Human Factors in Grain Harvesting Equipment Design

Agriculture is the third most hazardous industry in the United States, following mining and construction. Many agricultural hazards are related to the nature of agricultural machines and the conditions under which they are operated. Other hazards are the results of limitations of the human operator in relation to operational demands. Less than 5 percent of all U.S. workers were engaged in agriculture in 1974, but these accounted for 18.7 percent of all work related injuries. Farm machinery was involved in the greatest number of these accidents.

Human factors engineering can be applied to agricultural safety through the analysis of man/machine/environment/task relationships. Defining topics for specific studies can be aided by analysis of agricultural accident surveys conducted by state and federal agencies. Some important differences exist between industrial and agricultural operations. These necessitate research techniques for agriculture differing from those used in industrial ergonomics.

Isolation, self-reliance, self-management, and variability in conditions, operations and work schedules prevail in agriculture. A more thorough understanding of man-machine relationships is needed in studying the dynamics of field operations, especially when several pieces of equipment are being controlled by one operator. Routine service and maintenance operations are often hazardous in the way they are typically performed. A number of research frontiers exist in developing ways to study man-machine relationships under these conditions.

In this paper, particular reference is made to the grain harvesting combine, a machine which in 1.4 million man-hours of exposure in 1974 produced an accident frequency rate of 112 per million hours. While the total percentage of agricultural worker time on combines was only 1.2, 6.4 percent of all farm machine accidents occurred while using them.

Problems in using the combine are partially the result of its size, complexity, limited maneuverability, and the extended working hours over which it is often used. Field maintenance is frequently required and presents a variety of serious hazards.

This paper includes discussion of ergonomic problems involved in the operation and maintenance of the combine. Concepts, proven useful in other operator center high-demand situations, appear to be useful in improving safety in this basic and important mechanized agricultural operation. Recent surveys and research suggest the development of improved analytic techniques as well as new applications of basic ergonomics in improving basic operator tasks. Some new developments and current problems in these areas are also presented.