Look into the labor strikes and the resulting massacres of the late 19th and early 20th century. Many of these types of events involved federal troops or local law enforcement backed by various government entities. You can certainly find some that fit the criteria that you're looking for in your question.
Also, check out Lochner v. New York. This was a Supreme Court case about the freedom of contract and the 14th Amendment. The Supreme Court's ruling made it harder for states to interfere with areas of employment like the right to contract. This particular case was about long working hours at a bakery. The Supreme Court went on to overturn minimum wage laws and laws prohibiting yellow dog contracts (meaning a contract prohibiting an employee from joining a union) along with several other economic regulations.
Lochner was later overruled because of the effects of the Great Depression and the need to regulate the economy and the fight over laissez-faire economic policies.