The patent did not specify a round hole, or even a hole, used as an opener. It covered a "depression" in the blade of a folding knife that allowed the knife to be opened with one hand. The Spyderhole opener is a specific instance of that, but so are the trapezoidal depressions that allow one hand opening of a C27 Jess Horn with either hand.tvenuto wrote:This is interesting because Spyderco went from patenting the hole feature, to trademarking it, which is definitely non-standard. I'm no lawyer, but my google-fu is black belt, and there are sources that claim the current interpretation of the spyderco hole wouldn't be protected as a trademark due to its functionality. However, that would be decided by the powers that grant the trademark, and spyderco obviously got it granted, so the point is somewhat moot.
![Image](http://paulberetta.com/jess_horn_gallery/images/003_c27_jess_horn_pe_unnumbered_open_left.jpg)
The pocket clip Parker uses on their pens and mechanical pencils is functional, but its arrow shape can be trademarked because any number of other clip shapes work just as well.