John Kay was the son of a wool manufacturer in Bury, Lancashire. He was just a young man when he became the manager of one of his father's mills. Kay developed skills as a machinist and engineer. He made many improvements to the machines in the mill.
In May 1733, Kay patented his "New Engine of Machine for Opening and Dressing Wool". This machine included the Flying Shuttle. Before the invention of the Flying Shuttle, weavers had to pass the shuttle through the warp threads by hand. Kay's invention put the shuttle on wheels and controlled it with a driver. The weaver operated the shuttle by pulling a cord attached to the driver. When this cord was pulled to the left, the driver caused the shuttle to shoot ("fly") through the warp in the same direction. Pulling the cord to the right sent the shuttle back.
The Flying Shuttle was able to do the work of two people even more quickly. In 1753, an angry mob of weavers, afraid of the competition, wrecked Kay's house and destroyed his looms. However, since it halved labour costs, the textile industry was quick to adopt Kay's invention, but it was not so keen to pay him anything for it. The manufacturers formed an association which refused to pay Kay any royalties.
Kay lost all of his money in legal battles to defend his patent. He eventually moved to France where he is thought to have died a poor man.