Short answers, pulled from the story.
James Hargreaves (c. 1720 - the 22nd of April 1778) was an English weaver, carpenter, and inventor from Stanhill, Oswaldtwistle in Lancashire. He is credited with inventing the spinning jenny in 1764, a machine that allowed multiple threads to be spun at once, transforming textile production.
The name does not refer to any family member of Hargreaves. "Jenny" was a common Lancashire slang term for an engine in the 18th century. Despite school textbooks repeating the family-member myth as late as the 1960s and children's books as late as 2005, records show that neither Hargreaves's wife nor any of his daughters bore that name.
Hargreaves was granted a patent on the 12th of June 1770, after he had relocated from Lancashire to Nottingham. The patent gave him legal grounds to pursue Lancashire manufacturers who had begun using his invention without permission, though that action was later withdrawn.
The spinning jenny was confined to producing cotton weft threads and could not produce yarn of sufficient quality for the warp. The high-quality warp yarn needed for weaving was later supplied by Richard Arkwright's spinning frame, patented in 1769.
The idea is said to have come when a one-thread spinning wheel was overturned on the floor and Hargreaves observed that both the wheel and the spindle continued to revolve. He realised that if several spindles were placed upright and side by side, several threads could be spun simultaneously.
Hargreaves left Lancashire because of opposition to his machine from other hand spinners. They initially welcomed the jenny but turned against it when they saw yarn prices fall as supply increased. In Nottingham, he found the cotton hosiery industry ready to benefit from the increased provision of suitable yarn.