It is not the first time we take a look at LEGO patents, here at TBs . Before I've searched at the US Patent Office through the Google patents search engine, but this time we took also a look at the European Patent Office, Espacenet.
If you want to look for LEGO patents, you may search for 'INTER LEGO AG' or 'INTERLEGO AG' in the Applicant field, or 'LEGO AS' for the most recent patents (and many of the older ones as well).
Question here may be "Is it a way to somehow peek TLG future products?". The simple answer is - Hardly!
We can find many patents on modern LEGO Technic elements, whose inventors are some of the best know LEGO Designers from us.
Markus Kossmann, claimed several of the modern Technic Panels (64392, x1979, 64681, 64683). These patents are not much elaborate and consist in a set of drawings only. Hence they claim for "The ornamental design for a construction set element of the present design". The patents always refer to the side A of the respective panel, as the side B is just a symmetrical form of the same design. Markus also filled patents for the newest LEGO Technic frame elments (64178, 64179).
Interestingly none of these cover any of the unreleased prototype elements we have had opportunity to find so far (1 x 3 x 11 Panel Plate, 7 x 11 Open Center Frame). Probably unreleased elements do not use to have patents filled to protect their copyrights!?
Also the patents' Fill Date coincide with the year where these elements appeared in sets for the first time (2009). Guess these became visible only after a certain time, hence not helpful for a preview of what TLG would released ahead.
Anders Gaasedal (designer of 8043, Motorized Excavator), is also the author of some other LEGO Technic elements, according to the respective patents. The '1 x 5 x 11 Panel Plate' (64782) and the 63869 and 87408 connectors.
Gaute Munch, Technology Product Manager at LEGO System A/S in charge of PFS development, has also some interesting patents...
- One patent that describes the PFS itself (WO200713757)
- Another describing the LEGO WeDo elements (WO2009047225) - This one filled one year before the release of the first set (9580, WeDo Robotics Construction Set)
- And imagine, the RCX itself (US6939192, US6902461) - Apparentely filled much after the first release...
Interestingly Gaute et all, published other two patents about Function Bricks (US7708615, US20110151743). While the first one illustrates some known bricks, the later one extends the concept and introduces communication by means of light signals.
Does this enlighten us about eventual future products? The future will answer us!...

While we wait to see... one may spend the time reading some of the many other LEGO patents available online.

I'd recommend one that describes the mini Linear Actuator (92693c01) and its innovative clutch design (WO2011057640, A toy building set with an overload-safe linear actuator).