Measurement of the Mechanical Actions by a Walking Tractor in the Case of an Operator Crushed

—Elucidating the Crushing Mechanism when a Loop-Shaped Handle Restrained an Operator—

Abstract

Approximately 40 % of fatal accidents caused by walking tractors are crushing incidents. In this study, we supposed an operator was restrained between an object and a loop-shaped handle. The mechanical actions were measured as the walking tractor was driven, and the handle was in contact with the wall and ceiling at a height of 1.2 m. Results showed the maximum crushing forces were 4530±93 N, which can be fatal to the operator. We have formed an equation to estimate the horizontal distance from the tire axle and the point where the wheel ground reaction force is applied. From the measurements, the estimated distance was 89±1 mm. This shows the force was not active directly below the axle.