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FramesIt's time to take our first step into understanding the automobile. The best place to start is with the frame. The frame of the automobile is the main backbone. It acts just like the skeleton of bones we have inside our body. In our body, muscles organs, skin, and millions of blood vessels are attached to our skeleton. The car is very similar. The engine, wheels, body and electrical cables are all attached to the frame. It is the strongest part of the car.As cars grew bigger, longer, and were made to carry more weight the wooden frames were made out of steel in the early 1910's. The steel shape followed the same shape as the former wood design, which was known as a ladderrail frame.When the early cars were first made, they were mostly old horse drawn wagons with an engine. The frame of the wagon was made of wood that supported the seat, springs and the axles. The early frames were straight, strong pieces of wood running from the front of the car to the back, usually called frame rails. Smaller pieces of wood that connected the two rails were called cross members. The cross members were used to support the engine and transmission. The wooden frame was standard in the early cars and continued in some foreign cars until the 1940's. The last car to use a wooden frame was the english sports car; the Morgan, which used a frame made of ash, until the mid 1970's.As the automobile developed engineers realized that some types of cars, especially convertibles, required extra strength in the middle of the car. The "X" rail frame was developed. General Motors used the "X" rail frame on their Chevrolets and Pontiacs from 1958 ton 1964. The extra steel added weight to the car, but the resistance to a rollover and handling improved. This was due to a lower center of gravity.When the early 1950's came along engineers were quick to develop two new frame styles. The first style made by Nash, was the unitized construction or unibody.The unibody is widely used today by most automobile manufactures. The unibody style was designed toward the safety of the passengers, by enclosing them in a steel shell or cabin. The cabin was formed from structural parts, side walls, and a floor pan that would enclose the interior of the passenger section. Steel frame sections would be bolted or welded to this cabin for the trunk, axles and engine. Peugot, from France used unibidy design as early as 1928. The first common North American car to use unibody, was the Chrysler Airflow in the late 1930's.The other style that was made in the early 1950's was called the perimeter frame. This frame was like the old ladder frame but the middle, where the passengers sat, was wider than the front and back sections. Designers were able to make a "stepdown'' floor pan for the passengers. This allowed the car to have a lower look.Frames came a long way from the early wood design but their use as the main support for a car never changed. The trucks are still using the basic ladderframe rail for the strong support needed; and race cars have progressed into different materials; like aluminum, magnesium and carbongraphite frames.The next time your Dad or Grandfather has the old car out; ask them if you could use the "creeper" and look under the car. See what type of frame the old car has.Check out this link!http://www.autoshop-online.com/auto101/susp.html .... and this one...http://www.autoshop-online.com/auto101/susp1.html Your unit exam will be made up from the following list of questions:Frames:1. The two types of body and frame construction are:
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