Re: Safety Tips -Preventing Tractor Side Turnovers
PENPAGES: Factsheets from Pennsylvania State University
Preventing Tractor Turnover To The Side
In 1979 a middle-aged Pennsylvania farmer attempted to drive his tractor across an incline with the front-end loader raised and full of stone. The tractor upset, fatally crushing him. This accident was all the more tragic because he left behind a wife and three daughters.
Tractor overturns result in more farm accident deaths each year than any other farm-related accident. In four out of five of these accidents the tractor is turned over on its side. These statistics are especially unfortunate because nearly all overturns to the side could be avoided. To prevent side rollovers, operators must understand the specific hazards associated with the tractor and the proper safety precautions to apply when using them.
To keep your tractor firmly on the ground you must control the two forces which are responsible for side overturns. One of these forces is gravity. When setting on level ground a tractor's center of gravity is approximately two feet in front of and ten inches above the rear axle. With the center of gravity in this position the tractor is stable. However, if you change the position of the center of gravity by using certain types of mounted equipment or by driving across steep slopes, the tractor's stability decreases and the opportunities for an upset become greater.
Centrifugal force is the other major force involved in tractors turning over. This is the force that pushes at you and your tractor from one side as you turn it around or follow a bend in the roadway. Centrifugal force is dangerous; the pressure it exerts against a turning tractor multiplies rapidly as the tractor's speed increases. For instance, doubling a tractor's speed will increase the centrifugal force four times, tripling it will increase this force nine times. As the pressure exerted against a tractor becomes stronger, short or quick turns can rapidly change the vehicle's center of gravity and cause the tractor to tip over.
Fortunately, both of these forces can be controlled through the application of proper safety precautions. Remember, a tractor's center of gravity should be kept as low to the ground as possible when it is moving. A bump is less likely to tip the tractor and there is less chance that centrifugal force will upset it when turning. Drive a front-end loader with the bucket in a lowered rather than a raised position, and add weights to the tractor of off-set high-mounted liquid fertilizer tanks to keep the tractor's center of gravity low.
Tractors should be driven no faster than conditions will allow. Speed reduces the stability of tractors. Be alert to hazards in your path such as rocks, holes, or other obstructions and make your turns cautiously and at reduced speeds.
Proper braking of the tractor also reduces the chance of upset. Before driving at transport speeds, lock the brake pedals together to insure even braking pressure (brakes must be evenly adjusted). Braking only one pedal at higher speeds can force your vehicle to swerve abruptly and roll over. When travelling downhill, shift to a lower speed before you begin to descend and let the engine do most of the braking. This will help avoid the possibility of a runaway tractor which could flip over.
The safety-minded operator will avoid crossing steep slopes with his tractor if at all possible. Tractors are less stable on hillsides and can be easily over-turned. If you must work on slopes, however, use tractors with wide front ends and space your rear tires as far apart as possible. Watch for bumps or depressions and cross the slope slowly, keeping any side-mounted equipment on the uphill side of the tractor.
Together with safe operation of the tractor, it is a good idea to safeguard yourself with the extra protection provided by a roll-over protective structure. Roll-over protective structures are either protective frames or protective enclosures which, when mounted on the tractor, will limit most upsets to 90 degrees as well as protect the operator, particularly if the operator is wearing the seatbelt.
The safety oriented operator must always be concerned about maintaining his tractor in a stable position. By applying these five safety precautions the chances for turning your tractor over on its side will be greatly reduced:
1. Remember to keep the tractor's center of gravity as low to the ground as possible.
2. Drive no faster than conditions will permit.
3. Lock your brakes before travelling at transport speed and, if possible, use the engine as a braking mechanism when going downhill.
4. Avoid crossing steep slopes. If you must, drive slowly and position side-mounted equipment on the uphill side of the tractor.
5. Guard your life by installing roll-over protective structures on your tractor and use the seatbelt.
Author: Dennis J. Murphy, Associate Prof. Ag. Engr. Department of Agricultural Engineering, Penn State February 1988 PENpages Number: 0870186
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