Not to stay forever but longer than 60 days

I hold a 10 year 60 day stay at a time of entry in my U.S.A passport. My problem is i need to stay 80 days at a time 3 times a year. I am a buyer for my company and ship many containers a year. Is there a different visa i can hold without always going back to get a extension or leaving the country and just coming rite back in?