several, but none knife-related.
While on the subject, here's an interresting link for your bookmarks. The complete text of most US patents can be found at
http://www.patents.ibm.com/ibm.html
They have a nice search engine too.
Keep in mind, if you have a patent, that there are no "patent police" who run around ticketing people who violate your patent. It's up to you to sue people who violate it. If you don't make an effort to discover violations, and if you don't enforce your patent when you find violations, then you can be considered to have abandoned your patent and it can become worthless.
How do you make money off of your patents? Well, you can be the only one in your market with that product and/or feature. Spyderco, for example, was, for several years, the only company with a hole in the blade to open the knife. Another option is to license or sell your patent. Spyderco now licenses their hole to several other companies. Of course, this now means for Spyderco that they don't have the blade-hole market all to themselves anymore.
The real money comes when you can license your patent without intruding into your own market. I used to work for a company that made mobile computer equipment for warehouse and factory automation. In order to gain a market advantage over our compeditors, we patented the idea of a portable computer with a removable battery pack. A few years later, the idea of a laptop computer for traveling business people emerged. This is a completely different market from ours. But, for about five years (until our patent expired) all of the laptop makers, HP, Dell, Compaq, IBM, etc., had to pay us to license our removable battery pack patent. Checks just arrived in the mail, checks for which we had done absolutely nothing, free money!
The process of filing a patent application with the Patent Office is fairly simple. There are books on the subject. A quick trip to amazon.com, via the bladeforum link, of course, so that bladeforum gets a kickback on whatever you may buy, should turn up a few. The trick to getting the kind of payoff that our removable battery pack patent ended up making, the trick to getting a patent that a compeditor can not easily work around, is often just the correct choice of a few words in the patent text. This is a fine line. If your patent is way to broad, vauge, etc., then it can be thrown out in court. This is where a qualified patent attorney earns his keep.
Anything worth doing is worth doing right. If you think you've got something worth patenting, then it's worth patenting right. So, I'd suggest you talk to a patent attorney. BTW, patent attorneys usually aren't as greasy as most other lawyers.
Chuck
[This message has been edited by Gollnick (edited 30 June 1999).]