Studies on the Size and Shape of Safety Frame of 4-Wheel Tractors on Slope Lands

Abstract

By using a model tractor, some tests were made on the slopes of various grades in order to know the size and shape of safety frames required for limiting the roll of 4 wheel tractors to 90 deg.
The results obtained are as follows:
(1) Safety frames whose width and height are respectively about 95% and 85% of the wheel bases of tractors are effective in case of travelling on the slope of 10 deg.
(2) In case of the slope of 20 deg., slightly larger safety frames than those to that of 10 deg. are necessary.
(3) On the slope of 30 deg., even if the width of the safety frames were equal to the wheelbases, one and half times the height of the wheelbases is required in order to limit the roll of tractors to 90 deg.
(4) The relations between the height and the width of safety frames needed for safety operations on the slopes of various grades are shown in Fig, 5.
(5) Times during side-overturning in case of travelling at the speeds of 2.0-3.0m/s are respectively 1.2-2.5sec., 0.8-2.0sec. and 0.4-1.2sec, on the slopes of 10 deg., 15 deg, and 25 deg, These data show that the escape of operators from, seats during side-overturning is probably impossible, even on the slope of angles less than 10 deg.