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The Emerson Knives Wave Opening Patent: A Review After 10 Years

The tactical knife industry was revolutionized in March of 1999 when Emerson Knives was granted United States Patent #5,878,500 for Ernest Emerson's "Self-Opening Folding Knife" invention. Simply put, the ability to deploy the blade of a folding knife while doing little more than pulling the knife out of your pocket, has inherrent advantages with respect to speed, convenience, and ease of use.

Click Photo to View Emerson Commander Image

One of the Senior Editors here at, recalls the first time he saw someone carrying an Emerson Commander folding knife. It was a San Diego Police Officer who our Senior Editor happened-upon while standing in line at a 7-11 check-out counter. Being the gear/gun/knife freak that he is, our Senior Editor noticed that the officer's firearm was holstered on his right hip, while the distinctly pointy-shaped handle of the Emerson Commander was seen clipped onto the edge of the officer's left-side pants pocket. Just the carry-clip and the recognizable butt-end of the Emerson knife handle were visible.

It was obvious how that law enforcement officer was primarily counting on his Emerson Commander... it was his firearm retention back-up solution. Basically, if some lame-brain criminal were to make an attempt at grabbing the officer's gun, the following scenario would play out in a mere split second... 1) The policeman's right hand would act to cover, protect, or draw his firearm, 2) The policeman's left hand would snap the Commander out of his left-side pants pocket, which would cause Emerson's invention to automatically deploy the knife's thick blade, and 3) The officer would then proceed to ruin the criminal's day.

Ernest Emerson's brainchild, better known as the "Emerson Wave Patent", is now 10 years old and yet it is still THE UNDISPUTED pocketknife opening patent of the tactical knife world. By "undisputed", we mean that nobody has really been able to come up with a work-around that defeats Emerson's wave opening feature.

Yes, there are of course some far more technologically advanced knife opening patents, such as the different spring assisted mechanisms marketed by top knife manufactures such as Kershaw, SOG, Gerber, Buck, Benchmade, Camillus, and others. However, there are multiple variations of spring assist patents.

Or, take for example Spyderco's initially patented, and then trademarked, round thumb hole. Spyderco's thumb hole was to some extent ground-breaking for the single-handed folding knife market. But, work-arounds such as thumb studs and thumb screws of various shapes and sizes surged onto the market.

So, of all the various tactical knife opening mechanisms to have been patented, there really is only one that hasn't been defeated, the Emerson wave. The irony here is that the patented design is rather simple. But, that simplicity itself may be the reason for the patent's now decade-long impenetrable integrity and the resulting "Undisputed" title we are awarding it.

Take a look at the following excerpt from the Emerson Knives patent abstract (publicly available on the United States Patent and Trademark Office website). It's amazing to think that the paragraph below has been worth millions of dollars in business for Emerson Knives Inc.

Note the careful word usage in the patent text... It is pure patent lawyer-speak designed to be both descriptive and vague at the same time. For example, notice how Emerson's patent attorney describes the wave feature by saying "Preferably, the pin is hook-shaped". The attorney didn't simply say "the feature is shaped like a wave and designed to catch onto your pocket's edge" because that would be too clear-cut of a description.

By keeping things vague, Emerson and his attorney effectively won a very broad patent. And thereby, Ernest Emerson has prevented, for a whole decade now, a lot of very smart knife designers and engineers from being able to encroach upon the Emerson wave opening feature niche.

One can hardly imagine what new technolgies tactical knife designers are going to come up with in the future. There are probably some pretty cool things in store for all you knife aficionados. But regardless, it is interesting to step back every now and then to assess the great tactical knife innovations that have been serving us so well for some time now.



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