when was the first suitcase with wheels invented
at least to the 1930s
title: Baggage text: a wheeled suitcase in 1945 – but these were not successfully commercialized. The first commercially successful rolling suitcases was invented in 1970, when Bernard D. Sadow applied for a patent that was granted in 1972 as United States patent 3,653,474 for "Rolling Luggage". The patent application cited the increase in air travel, and "baggage handling [having] become perhaps the single biggest difficulty encountered by an air passenger", as background of the invention. Sadow's four-wheeled suitcases, pulled using a loose strap, were later surpassed in popularity by suitcases that feature two wheels and are pulled in an upright position using a title: Suitcase text: polyester prevailed. The original 'Halliburton' aluminum travel cases were handmade for Erle P. Halliburton's personal use in 1938. In 1950 Rimowa introduced the mass market aluminum suitcase based on the Junkers Ju 52 airplane shortly followed by Zero Halliburton. Nylon suitcases prevailed afterwards. Wheeled luggage was first patented by Bernard Sadow in 1972 though the first commercially-available wheeled suitcase, the Rollaboard, only emerged in 1987. In the mid 1980s, Andiamo was the first company to incorporate ballistic nylon into luggage. The first suitcases made of polycarbonate were made in 2000 by the German luggage maker Rimowa. Most luggage manufacturers have title: Suitcase text: Suitcase A suitcase is a form of luggage. It is often a somewhat flat, rectangular-shaped bag with rounded square corners, either metal, hard plastic or made of cloth, vinyl or leather that more or less retains its shape. It has a carrying handle on one side and is used mainly for transporting clothes and other possessions during trips. It opens on hinges like a door. Suitcases lock with keys or a combination. Originally, suitcases were made of wool or linen. Leather also became a popular material for suitcases. It was used to cover wood suitcases or just on its own title: Wheel construction text: tire, and a central disc, also known as the disc or spider, which connects the wheel to the vehicle. Wheels are usually of two types: semi-drop center (SDC), used in trucks, and drop center (DC), used in other vehicles. The wheel is one of the most important inventions, but its inventor and exact date of invention are not yet known. The oldest known wheel was excavated from Mesopotamia, believed to be 5500 years old. This earliest wheel was a potter's wheel, used in the city of Ur in Mesopotamia (present-day Iraq), invented by Mesopotamians (also known as Sumerians) around 3500 title: Baggage text: – light-weight wheeled carts or harnesses on which luggage could be temporarily place or that can be temporarily attached to luggage – date at least to the 1930s, such as in US patent 2,132,316 "Luggage carrier" by Anne W. Newton (filed 1937, published 1938). These were refined over the following decades, as reflected in patents such as US patent 2,650,105 A "Luggage carriage" (filed 1949, published 1953) and US patent 2,670,969 "Luggage carriage harness, both by Kent R. Costikyan. However, the wheels were "external" to the suitcases. Patents were published for wheeled luggage – a wheeled trunk in 1887, and