how can we purchase the rights to a patent

From the USPTO records, you can find out who owns the patent and can contact them directly or you could contact the attorney listed on the face of the patent who represented the patentee. You might want to initial find out if the patent owner would be interested in sell the patent in an anonymous manner, such as through an attorney who is not know as being you intellectual property attorney so that, if there is no interest on the part of the patent owner, the patent owner will not be looking to monitor your company's activity. It is also suggested that, first, you check to see if the patent has not lapse due to failure to pay maintenance fees, and it is also suggested that you have the claims of the patent evaluated to insure that the cover what you want to do.