History of Trolley Case   Early suitcases were usually wrapped with leather, rattan or thick rubber cloth on a hardwood or steel frame, and the corners were fixed with brass or leather. A handle was installed on it and closed with a button. This kind of traditional suitcase can only be carried or walked, which is very inconvenient to use.   This phenomenon did not change until 1972. A friend named Bernard Sadow put wheels on the suitcase, and the wheeled suitcase finally came out!   In 1972, Bernard Sadow applied for a patent with the patent number of 3653474 and the patent name of rolling luggage.   Bernard is an executive of a suitcase company in the United States (he has become an executive and is still in the front line of product design, full marks). Once he was shopping with his wife in the supermarket. When he was annoyed that the loser women wanted to buy again, he saw a young man pulling the shopping cart behind him and throwing his favorite goods into it. Bernard felt that this young man was so simple and unaffected that he was not at all the same as those flirtatious bitches outside, so he seriously appreciated the young man and got the inspiration of the wheeled suitcase.   However, Bernard's design has great defects. The center of gravity of this wheeled suitcase is unstable, and it will fall down in case of turning, uneven road surface or emergency stop. Therefore, xinxiuli made an improvement on the design of the box, replaced the soft rope with one that can be accommodated, widened the box, and won the design award in the 1980s.   Obviously, this design is still very stupid. You need to lift one end when towing, which is very laborious. So another brother named Robert Plath pushed the rolling wheel of history. This man is the captain of Northwest Airlines. After retirement, he has nothing to do. When playing with boxes at home, he erected the boxes and installed wheels and levers, creating the prototype of modern trolley boxes. This year is 1987.