At times you will find a patent number on the bottom of a pickup or other company literature. It is possible to look up names, dates, pickup class and pickup references used by the patent office. I would suggest going to a book store and look for a book on patents, trademarks and one I would suggest is called: “Patent it Yourself” by Patent Attorney David Pressman. It is published by the Nolo Press, Inc., 950 Parker Street, Berkeley, CA 94710 and their phone number is 800-955-4775. The ISBN number is 0-87337-364-2