Microsoft's worst kept secret keeps on spilling out thanks to patent filings related to the device. This latest one was unearthed by h0x0d on Twitter, and appears to detail a locking mechanism for the device's folding display.
Microsoft's Andromeda tablet is expected to be a dual-display folding device, complete with telephony and a unique Windows operating system (based on Windows Core OS) designed specifically for this new form factor. The Andromeda device will likely sport the Surface branding, and focus on digital journaling with robust inking features.
According to this new patent, the device could include magnetic locking mechanisms embedded in the display, allowing it to become locked in a folded state. The patent details the use of pivots and magnetic shielding to allow the locking mechanism to do its job, while noting that the device's hinge "may provide freedom of rotation from 0 degrees to 360 degrees." Presumeably, the magnets would be able to pivot to provide locking capabilities for both screens facing out, and screens closed. You can take a look at the full patent right over here.
As with all patents, don't take this as a confirmation of Andromeda or its features. As we know from the Surface Mini, projects and prototypes can get canned at the last minute.