This patent is for putting a gear on a spindle shaft. This has been done in automobiles, airplanes and machines for years. Putting a gear with spindle spacing on the inside and actual gears on the outside is common. Doing so on a servo motor spindle shaft is no different. BTW, I am not the first to complain about this patent.

If one chooses to build something that uses a gear on the spindle shaft of a servo are they doomed to license fees or can the patent be contested?

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    Here is the question: Do you have prior art that discloses an embodiment that fits within the claims of the patent? Nov 15, 2012 at 11:48
  • Look at the "countershaft sprocket" for a 1991 Ducati 900ss. Or any Ducati motorcycle from the 1980s onward. Splined shaft. See "Drawing 3" from the parts catalog of a 2000 Ducati Monster 750: ca-cycleworks.com/c/media/parts_catalog/2000/M750_Usa-00.pdf
    – Krista K
    Dec 30, 2013 at 8:53
  • And there are many many patents on gears or sprockets where the outer ring with teeth attaches to a separate inner hub part. Including the nuances of when the materials are different. Also when the intention of different materials are for the purposes of: reduced weight, easier manufacturing, decreased cost. Not that I'm investigating motorcycle sprocket patents right now...
    – Krista K
    Dec 30, 2013 at 8:59

1 Answer 1


The independent claims all appear to be significantly more specific than you state. Can you provide evidence that the specific configuration described in the independent claims was actually in use before the priority date?

Whether the transfer of some known technology into a different application area is obvious or not, strongly depends on the circumstances of the individual case.

The examples you mentioned all concern machines which are significantly larger, made from different materials, are significantly more expensive, have to deal with entirely different forces, and may be designed for entirely different life spans. Therefore, it does not necessarily strike me as immediately obvious to use the same gear configuration in a small and inexpensive hobby servo motor, where the technology and requirements may be entirely different.

Generally, one has to remember that it is fundamentally impossible to judge obviousness by looking at the claimed invention alone. Obviousness is a concept that is always defined relative to the pertinent closest prior art.

The closest prior art in this case would be the (most similar) type of gear connection previously used in hobby servo machines. The question then is whether the skilled person would find the motivation to modify that closest prior art to arrive at the claimed solution.

This is an analysis that should be performed in a much more rigorous and systematic manner than looking at the solution and then saying "hey, this looks like something I know". This latter approach has all the signs of hindsight (a.k.a. ex post facto analysis), or what I like to call the Any Idiot Could Have Come Up With The Car fallacy.

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