RV History: The evolution of the trailer hitch

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    By Al Hesselbart
     
    The history of devices to connect a load to a towing device goes back many centuries. From a wooden yoke by which cattle were attached to many types of trailers to leather collars used to connect horses there have been many types of “hitches” used through the years. When mechanical pulling power was created with the advent of the automobile, the evolution of the trailer hitch began.

    At first rudimentary trailers were attached to autos by two blacksmith created bars attached to the trailer and the car with holes through each and a bolt and nut used to connect the two parts.

    In 1917, Glenn Curtiss of Curtiss-Wright aviation fame developed and patented a hitch device based on an auto’s fifth wheel or spare tire. Since cars needed their spares, the device converted to a much smaller airplane tire but still provided an air-cushioned attachment. That tire based hitch was modified by the US Army during WWII to use a steel plate instead of a tire and wheel. It was nearly 25 years later around 1965 when the heavy plate as used on semi tractors today was downsized to create the modern RV fifth wheel. 
     
    In the late 1920s, Frank Zagelmeyer of Bay City, Michigan, patented a ball and receiver hitch that was more secure than the tang and bolt connection and allowed much more flexible operation. The early trailer ball was very similar to those known today but was one ¾ inch in diameter, smaller than the smallest 1 7/8 size used today. The early receiver had a swing away section that enclosed the ball rather than the modern clamping internal latch.
     
    Through the years many variations have come forward. The pintle hitch uses a heavy hook mounted on the towing vehicle with a ring on the trailer tongue to set over the hook, or pintle, and is used for hefty loads. 
     
    The gooseneck hitch is somewhat a cross between the fifth-wheel and the ball and receiver. In it, a heavy arm reaches forward from the trailers in the form of a gooseneck and bends down to set into a trailer ball mounted over the axle of the towing truck. It is generally used for heavy cargo loads on large trailers. 

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    Edward Price
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    Edward Price

    The American style ball & socket hitch has remained unchanged for over a half century, while in Europe and Australia, a number of alternative designs are used. Many of these foreign designs feature automatic coupling alignment or much more secure pin or universal joint connectors. How does the old ball hitch compare with these foreign designs, and are the foreign designs legal for USA roads?

    mollyd
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    mollyd

    Thank you very much Miss, Emily Woodbury

    Jim Guld
    Guest
    Jim Guld

    Good stuff, Al.