“Indicate precisely what you mean to say…”
Good advice for letting someone know you’ll still need them when they’re 64. And also good advice when writing up patent specifications. Consider what happened to Clyde Nason when he tried to patent a miniature pump. The heart of the device is a loop of shape memory alloy (SMA) that engages one tooth of a “gear”, as shown in the figure below. As the SMA is cycled back and forth through it’s transition temperature the loop alternately pulls on the engaged tooth, rotating the “gear”, and extends to engage the next tooth.
So what went wrong?
The examiner went searching for pumps that were driven by SMA material and for rotary gears driven by SMA material and was able to find prior art in both those areas. Voila – Nason’s invention is “obvious” since you can combine these two to get an SMA-driven-gear driven pump, right? Wrong, since, among other reasons, the gear driven by SMA in the prior art was actually a linear rack that rotated a pinion gear…not really applicable to using SMA to directly rotate a gear.
Happily, the Patent Board of Appeals ultimately threw out the examiner’s rejection but could Nason have avoided the extra expense of a appeal?
It’s always hard to predict what motivates an examiner to go off the deep end and make obviousness rejections that make no sense, but the one thing I always like to keep in mind is that YOU are the expert in your particular invention and the EXAMINER doesn’t have the time to dig deeply into your invention…and, frankly, is likely to be a POSITA (Person of Ordinary Skill In The Art) at best. Thus, it is incumbent on you, the expert, to teach the ordinarily skilled examiner about your invention. And the best way to do that is, IMHO, is to be as precise and unambiguous as you can in preparing your patent specification.
In Nason’s case, his choice of the word “gear” to describe the round item with teeth in his pump was a mistake. It is not a gear, it is a ratchet or cogwheel. And the loop of SMA is acting as the pawl to ratchet the wheel around. Had Nason called it a cogwheel and described the action of the SMA as a pawl I expect the examiner would not have searched for gears driven by SMA material. Of course, the real problem here is the appalling (no aural pun intended) lack of mechanical understanding of the examiner, but nevertheless your goal is to get your patent allowed and that is best accomplished by realizing that YOU should lead the patent examiner by the nose, if necessary, to the proper understanding of your invention vis-a-vis the prior art.