Is ours hindu Joint family?

My father started a proprietorship firm with his own efforts,without any inherited property from 1972 to 1982,in 1983 my father with the intention to expand the business he added myself and my elder brother as a working partners without any capital,he divided the profits in the ratio 40%:30%:30% respectively.we filed individual income tax files since we entered in to the partnership.In 1993 my father and elder brother were released from the firm by signing a dissolution of partnership and I also settled the amounts as per the balance sheet and now I became the individual proprietor of the same firm,my elder brother separately started his own business in name of his own proprietorship firm.All of a sudden after 22 years after my fathers death in 2013 my brother claims my property and property in the name of my wife along with my fathers property.He has lodged a partition suit in the court according to hindu joint family demanding 1/3rd share which I have earned with my own efforts. please tell weather ours is hindu joint family,and further what action should I take? As I am looking for a good lawyer who can provide us a permanent solution as soon as possible. and 1 more question- In this case can the court pass injection order for my personal properties? and what is the procedure to dismiss the case at this stage?