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...


A Utility Patent, also referred to as “a patent for inventions,” is issued for the invention of a new or a new and useful improvement of an existing Utility Patent. Under current law (effective June 8, 1995), utility patents are granted for a period of 20 years from the date the patent application was filed.

A Design Patent is issued for new, original ornamental designs for articles of manufacture. The Design Patent permits its owner to exclude others from making, using, or selling the design. Design patents are granted for a period of 14 years.

Patent owner's exclusive rights have two major limitations. They are “Functionally Equivalent Products” and “Invalidation”. A patent excludes others from making, using, or selling products or using processes that do substantially the same work as the patented invention in substantially the same manner. However, a patent does not protect the patent owner from competition from functionally equivalent products or processes that work in different ways.

For locksmiths, a functionally equivalent product and process that works in different ways are battery operated automotive electronic keys. A transponder requires energy provided by the vehicle to transmit the signal. A battery operated electronic key supplies the power to the circuit board electronics to transmit the signal.

Once a patent has been issued, the validity can be challenged, requiring the individual or company in control of the patent to bring suit. The defendant usually asserts that the patent was not unique and a mistake was made by the U.S. Patent and Trademark Office granting the patent, which does happen.

An interest twist on a utility patent is the owner of the patent is required to pay a maintenance fee to keep the patent from prematurely expiring. The fees are due at 3.5, 7.5 and 11.5 years.

Once a locksmith has agreed to purchase patent protected keys and keyway lock mechanisms, the lock manufacturer has a set criterion for the locksmith to follow to sell the customer additional keys and locks. In many instances, customers must provide identification and proof of employer before the locksmith can cut additional patent protected keys.

Patent protected key blanks usually operate higher security lock mechanisms. However, the KeyMark patented keys and keyway lock mechanism’s specified purpose was key control that can be used with interchangeable/removable cores, mortise and rim cylinders and key-in-knob cylinders. Yale KeyMark cylinders shall contain standard pins, a portion of which, both bottom and top, shall be spooled for greater resistance against picking. “U.S. Utility Patent number 5,176,015 protects Yale KeyMark keys from unauthorized duplication until the year 2011,” says the  Yale® KeyMark® Patented Keyway Cylinders catalog.

Some companies need just key control. Other companies want additional entry protection. These companies may want locks that have a second or third lock mechanism or a unique lock mechanism that provides a greater degree of protection in addition to key control.

And then there are companies that want key control, some entry protection and tested protection that comes with the UL437 Listing and/or ANSI/BHMA A156.30. Both of these rating include tests for forced and covert entry. Although ANSI/BHMA A156.30 does reference high security standards, neither UL437 nor A156.30 define a “high security lock.” In addition, neither of these standards is complete, as they do not require tests for key bumping.

 “For effective mechanical protection against most forms of attack as well as protection against unauthorized duplicate keys, Medeco3 cylinders are recommended. Security features including hardened steel components, pins that must be elevated, rotated, and interact with a sidebar and a slider, and additional pick resistant features…”, quoted from Medeco Products catalog 2009.

Note: If your customer wants or is required to have UL437 Listed or ANSI/BHMA A156.30 security rated, be aware that small format interchangeable cores cannot be installed. All small format interchangeable cores are not UL437 Listed.  

When considering installing a patented lock mechanism, it is important to first examine the opening. If the door, jamb, strike receptacle and surrounding walls provide enough protection, a patented keyway lock mechanism that is UL437 Listed or ANSI/BHMA A156.30 security rated can provide a reasonable level of security.

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