A snip from Tom. Isn't it wonderful to have people who know things!

In Canada and pretty well the remainder of the world, a patent application is "laid open" at 18 months, meaning that you can examine it. The U.S.A. is just moving to adopt that convention. Let me know what you're looking for (if you don't mind) and I can find the European equivalents if they exist and send them to you.

As you know, a patent has a "teaching" part and a "claims" part. In exchange for a new teaching, the gov't grants a time limited monopoly to the invention described by the claims. The claims have to be supported by "new" teachings in the teaching portion - they must not have been "taught" (described) in any other document anywhere else in the world, and they must not be "obvious" - that is they must have an "inventive step". During the examination process, the initial set of claims is normally whittled down. So, an application may start as, "A motor and support structure comprising a small planet circling a yellow-white star, gravitationally connected to a motor..." and then end up with a lawn-mower claim... Okay - maybe not that bad, but the claims in an early application may be much broader than the final version, so your reading of an early version of a patent might want to differentiate as to whether you are following the teachings (which cannot be elaborated - no new material once you initially submit it, due to date stamp purposes) and the claims -- which can be modified until you run out of money to keep prosecuting. In some countries (like Canada) the entire prosecution process is laid open. In other countries, you only see the beginning and end results, and can then apply for a copy of the "file wrapper" which contains all the correspondance between Patent Office and applicant.

-- Anonymous, April 26, 2000

Answers

Query:

Is there actually an efficient stirling cycle engine, or is it still developmental? Anyone know of any functioning production sites?

-- Anonymous, April 27, 2000