I really like this one. As a "bare" name, with no development, I would expect to sell it for low xxx.
But, I probably wouldn't sell it for that and here is why:
First of all, while patents (in the US at least) are supposedly available for viewing and search on the net, the interface is horrible and the process is extremely tedious to say the least. There is no very good or simple method to make sure that the product that you envision patenting is unique because it might be called something completely different and be described using different terminology. And, seeking a patent is a very costly and laborious process in the first place, but finding out if there is an existing patent already is an absolute nightmare that usually very quickly becomes the most expensive part of the process. This domain quite easily targets those who are looking for an easier or cheaper way or even just A way to do it. You could monetize by having links to Patent Attorneys, which are considered by most to be a necessity for going through the process. But it wouldn't stop there.
If you could come up with a way (and I have no real idea how, but it might be possible) to make an interface for searching for related keywords and/or concepts on the existing system through your site, you could probably get enough traffic to make your hosting provider cringe.
There are also the people who would be looking for things like "Tesla Patents," "HHO PATENTS," WATER CARBURETORS, ETC.
And, then you could look at providing links to rapid prototyping services and equpment (including the home "printers" that are now available).
With a forum, you could have others helping others find info. and monetize from advertising.
There are a number of companies that deal in "inventor's support." These companies supposedly help budding inventors get their products to market. Several of them have some very nice affiliate programs that can pay well and you could have reviews of them on a site built upon this domain.
Anyway, that's what I thought off, off the top of my head. I think this one has some great potential and I wouldn't be in any hurry to liquidate it anytime soon.
Just My Opinion, Of Course. Best Wishes.