"The present-day concept of the relatively longer "week-end" first arose in the industrial north of Britain in the early 19th century... In 1884, the Federation of Organized Trades and Labor Unions, a predecessor of today’s AFL-CIO, called for all workers to have eight-hour days by May 1, 1886, playing a crucial role in the push for a five-day workweek."
Violence definitely happened in the US labor movement.
https://en.wikipedia.org/wiki/Colorado_Coalfield_War
https://en.wikipedia.org/wiki/Battle_of_Blair_Mountain
https://en.wikipedia.org/wiki/Homestead_strike
https://en.wikipedia.org/wiki/Battle_of_the_Overpass
Ford hardly invented the weekend, either.
https://en.wikipedia.org/wiki/Workweek_and_weekend#History
"The present-day concept of the relatively longer "week-end" first arose in the industrial north of Britain in the early 19th century... In 1884, the Federation of Organized Trades and Labor Unions, a predecessor of today’s AFL-CIO, called for all workers to have eight-hour days by May 1, 1886, playing a crucial role in the push for a five-day workweek."