Patented, Proprietary and Restricted Key Blanks and Related Lock Mechanisms

To preface this article, I am not an attorney and the following information is intended to provide a general understanding of the terms higher and high security, key control, patented, restricted, proprietary and other terms used by lock manufacturers and...


Restricted and proprietary key blanks come in just about every head configuration. Coined into the key blank head may be the manufacturer, the distributor and/or the locksmith’s name. There can also be proprietary and restricted key blanks that have a neuter bow, with no identifying information. The idea is usually to not make people question the keys.

Depending upon who you are and what the application is for the restricted and proprietary key blanks, there usually is a minimum buy-in and annual purchase requirements. This amount is determined by the lock manufacturer and/or distributor. The greater the degree of exclusivity, the higher the buy-in and the larger the annual purchase requirements.

Restricted and proprietary keys and keyway lock mechanisms have at best a “gentleman’s agreement” degree of security. The mystique surrounding these keys keeps them safe by remaining an unknown commodity.

There is no law making it illegal for other companies to manufacture or sell. Most manufacturers or distributors of restricted and proprietary key blanks attempt to spread out the use of their products. In this way, without a large enough demand for the key blanks, other manufacturers will not be willing to invest the capital necessary. Also, should a lock manufacturer decide to make another’s restricted key blanks and keyway lock cylinders, the offended lock manufacturer could make the competitor’s products, basically ending those restricted keyways. It is rare for a restricted key blank to be manufactured by a competitor.

Prior to investing in a patented, restricted or proprietary keyway lock mechanism and key blanks, there are a number of points to consider. Probably the most important is the length of time remaining until the patent expires. This will be the amount of time you have to sell the patent protected product. Once the patent expires, your customers will have to be notified of the expiration and the options for new patent protection.

If you are considering selling a restricted keyway lock mechanism and keys, determine if any other distributors have the ability to sell your keyway lock mechanism and keys where. Plus, where are other locksmiths who have the same keyway? Find out how much money buys how much exclusivity.

Another point to consider is whether specialized equipment is required to service the patented keyway locks and key blanks. What is the cost of a keying kit and replacement pin tumblers? How are the lock cylinders serviced? What type of key machine is necessary in order to originate keys?

KeyMark keyway lock cylinders and key blanks have three distinct components: an upper portion or blade, a middle ledge, and a unique, lower angled portion or leg. The shape of the key blanks prevents duplication on standard machines. However, to originate KeyMark keys, a code machine with the proper vise jaws is required. I believe that there are three different angles for locksmiths who purchase the KeyMark. I believe the Medeco KeyMark has two available keyways, they are the seven and fourteen degree security leg keyways. I believe the Yale KeyMark has a 10 degree leg keyway. The Security Leg angle is not interchangeable.

KeyMark x4 isMedeco’s latest utility patent protected, key control lock cylinder for small and large format interchangeable core cylinders, conventional mortise, rim and key-in-knob cylinders. “One key will operate interchangeable cores and conventional cylinders. With patents extending through 2027…Keys can be cut using many standard code type key machines such as the A1 Green Machine, HPC 1200 with the B clamp and the CW-90MC cutter and card for cutting Best/Falcon/Arrow, the ITL 9000, and the Pro-Lok Blue Punch,” according to the KeyMark x4 Cutsheet Proof 5.

We Recommend