While climbing a properly set up aluminum extension ladder, a workman fell with the ladder after a crack completely penetrated one of the side rails. The crack initiated at a site which corresponded exactly with the location where the side rail normally rests on a steel ladder rack during transport. There are a number of recommended countermeasures in the ANSI ladder standards for preventing ladder damage from road shock and vehicle vibration including one which suggests securing the ladder at each support point. This bulletin demonstrates that the latter recommendation alone will prevent fretting damage and its associated loss of structural integrity.

In 1991, there were 2,687,107 bowhunters in the United States following a rich tradition that is thousands of years old. The modern bowhunter is typically equipped with a compound bow, camouflage clothing, dehydrated food and a tree stand. The tree stand, shown in Fig. 1, is mounted 10 to 12 feet above the ground. Here it offers the hunter a large field of view and a stationary position generally outside the animal’s field of vision and scent. Bowhunters wear a safety belt for fall protection when climbing to or hunting from a tree stand. This bulletin focuses on the minimum weight design of the safety lanyard.

A rigid body mode of failure has been identified in two piece adjustable grinding wheel guards for portable grinders. Under the action of a fragment storm, the upper portion of the guard may tilt and allow an escape displacement to develop at the leading edge of the protective skirt. Three approaches are described for analyzing this behavior: a very rough analytical investigation, static testing, and dynamic wheel breakage testing of the guard. Each reveals the shortcomings of the commercially available guard.

one year, rollover impacts accounted for 9 percent of multiple-vehicle accident fatalities while rollovers accounted for 51 percent of single-vehicle accident fatalities. Light-duty vehicles include passenger cars, pickup trucks, vans, and sport-utility vehicles. Although much attention has been given to the study of vehicle rollover stability and to rollover-accident avoidance, research has yet to conclusively uncover an individual vehicle characteristic or rollover-stability measure which can account for the rollover accidents experienced by light-duty vehicles. The scope of the research abstracted herein 4 includes the full-scale experimental tests of eight light-duty vehicles as well as the validation of complex computer models for these vehicles and the computer simulation of these vehicles in soil- and curb- tripped rollover situations. The results of both experimental testing and computer modelling are analyzed against various vehicle characteristics, measures of rollover propensity, and the environmental tripping scenarios. 5 CONCLUSIONS The analyses support the conclusion that tripping from soil is qualitatively different than tripping over curbing since different types of vehicle characteristics are correlated to rollover velocities in soil-tripped situations than in curb-tripped situations. Vehicle-geometry parameters, including the static stability factor, are the most significant factors for soil-tripped rollover situations, while suspension- stiffness characteristics are most significant under curb-tripped situations. In addition, the levels of correlation are generally higher in soil-tripped analyses than in curb-tripped analyses.

one year, rollover impacts accounted for 9 percent of multiple-vehicle accident fatalities while rollovers accounted for 51 percent of single-vehicle accident fatalities. Light-duty vehicles include passenger cars, pickup trucks, vans, and sport-utility vehicles. Although much attention has been given to the study of vehicle rollover stability and to rollover-accident avoidance, research has yet to conclusively uncover an individual vehicle characteristic or rollover-stability measure which can account for the rollover accidents experienced by light-duty vehicles. The scope of the research abstracted herein 4 includes the full-scale experimental tests of eight light-duty vehicles as well as the validation of complex computer models for these vehicles and the computer simulation of these vehicles in soil- and curbtripped rollover situations. The results of both experimental testing and computer modelling are analyzed against various vehicle characteristics, measures of rollover propensity, and the environmental tripping scenarios. 5 CONCLUSIONS The analyses support the conclusion that tripping from soil is qualitatively different than tripping over curbing since different types of vehicle characteristics are correlated to rollover velocities in soil-tripped situations than in curb-tripped situations. Vehicle-geometry parameters, including the static stability factor, are the most significant factors for soil-tripped rollover situations, while suspensionstiffness characteristics are most significant under curb-tripped situations. In addition, the levels of correlation are generally higher in soil-tripped analyses than in curb-tripped analyses.