Apple Inc. “keeps getting broad and fundamental patents on basic smartphone features. And its latest, granted today, is another doozy: the ability to swap to an app while maintaining a phone call,” Erik Sherman writes for CBS News.

“Patent number 8,082,523, called Portable electronic device with graphical user interface supporting application switching, has a vital independent claim that is much broader than it looks on first reading,” Sherman writes. “You have to admire the craft of the lawyers on this one. Although the main claim is quite specific, it manages to nail down the steps in just broad enough a way to make to clumsy for a competitor to work around.”

Sherman writes, “Whether this patent, the recent location services one, or others granted since getting into court with competitors, Apple continues to harvest a collection of legal clubs that can keep other handset manufacturers tripping time after time. It has yet to raise all these clubs in court, but it could — and probably will in time.”

Read more in the full article here.