Ohio Salary Laws for Supervisor

[GRANDMASTER24]

I am a supervisor and also a working supervisor in which I do manual labor when the company I work for are short of employees.
I work for a company in which I was forced to be put on Salary because they had me working in excess of 60+ hours per week. And they were paying me hourly in which I made 800+ take home. The contract which they wrote up for myself which I did not have to sign. States that I take home $615 per week and I work at least (40) forty but no more than (50) fifty hours per week and I work every other Satuday. I also would recieve bonus's every 3 months, 2% of the profit of all work that came in. My work consisted of supervising other employees doing manual labor. The contract became effective almost 2 years ago without my permission and it happened on the week in which I had worked 75+ hours. Which, I should have brought home $1,000.+. I was told I had to take the $615 per week and that was that. Which, at the time I thought I had no other alternative. Since that time I have worked 60+ hours a week and almost every Saturday, and I am on call 24 hours a day 7 days a week, with no other compensation but the $615 per week. No bonuses at all. My question is for a supervisor, is there a law about how many hours I have to put in per week and if so, how many. And if I work more than that alloted hours should I be compensated for the extra hours that I do work? Also, should my wages change when I am supervisor compared to a working supervisor in which I do manual labor when they are short of employees? I have heard that there are labor laws regarding the above mentioned, I am upset about the situation but, I am afraid to say anything because I don't want to lose my job. But, I don't want to be taken advantage of either. I would really appreciate any information on my dilemma.
Thank you in advance and God Bless You.

[LConnell]

If you are a true supervisor, with the ability to hire and fire, etc., and you do not spend more than 50% of your time doing, "manual work", you would be considered exempt and not eligible for overtime. If you are primarily doing manual work, you are probably non-exempt and you are owed overtime. http://www.dol.gov/elaws/esa/flsa/screen75.asp