A patent-holding company that stands to win 12.5 cents for every iPhone sold has filed a new lawsuit (PDF) against Apple.

Ironworks Patents LLC is a patent-enforcement company formed earlier this year, with no apparent business other than filing lawsuits over patents. It's a business model that's now decades old, and companies that engage in it are often derided as "patent trolls."

Yet Ironworks isn't your everyday patent enforcer. The company has inherited a patent portfolio belonging to MobileMedia Ideas LLC, which has already proven its value. MobileMedia Ideas was a kind of "corporate troll," majority-owned by a patent pool called MPEG-LA. Minority stakes in MobileMedia were owned by Sony and Nokia, who also provided patents that could be used in lawsuits against other tech companies.

Last year, a Delaware federal jury found that Apple's iPhone infringed a MobileMedia patent and ordered Apple to pay $3 million in damages. A judge later increased that amount to $10.7 million, or $0.125 per infringing unit, which included millions of iPhone 3G and iPhone 4 units.

While that case is on appeal, the MobileMedia portfolio was sold to Ironworks. On Friday, Ironworks filed a new lawsuit seeking to ensure it has the rights to collect royalties for all later iPhone models—from the iPhone 4S all the way up to the still-not-shipped iPhone X.

Corporate paperwork filed with the Illinois Secretary of State indicates that Ironworks is controlled by David Ruder, a Chicago attorney who has spent his career in patent monetization. Ruder worked at Altitude Capital Partners, and later Ocean Tomo, before joining defensive aggregator RPX in 2008. Earlier this year, he formed a company he called Ximota Intangible Asset Finance "to leverage his experience in owning, financing, and licensing intangible assets."

Reached by telephone on Monday, Ruder declined to comment about the Ironworks litigation. Apple didn't respond to a request for comment about the case.

The invention of “ring silencing”

US Patent RE 39,231 describes ring-silencing features on mobile phones, and it originated at Sony. Essentially, the '231 patent describes allowing the user of a communications device to receive a call, while changing its volume but "leaving a call-ringing state." In other words, the patent is about pressing a button to silence your cell phone. The patent was filed in 2001 and has a priority date of 1994.

Two other patents originated at Nokia. US Patent No. 6,850,150 describes a mobile phone with silent alarms. The patent also describes the device's operations, including alarms that vibrate the device. It originated at the Nokia Corporation and was filed in 2000. A third patent, 8,847,734 , describes a vibrating silent alarm that's specifically set off by an incorrect user code. Filed in 2004, the '734 patent is a descendant of the '650 patent and claims the same priority date.

The '231 ring-silencing patent has been used together with a group of four other patents—all originating at Sony and Nokia, all transferred from MobileMedia to Ironworks—in at least two other lawsuits as well. In June, Ironworks sued LG Electronics (PDF) in Southern California, claiming that LG should have known its mobile phones, tablets, and computers infringed the patents since at least 2010. That's the year LG was accused of infringement by a letter from the patents' previous owner, MobileMedia.

In July, Ironworks sued Huawei (PDF) in the Eastern District of Texas. The complaint details years of discussions between MobileMedia and Huawei, but a license deal was never struck. Ironworks' lawsuit against Huawei seeks to collect royalties on the Huawei Ascend P7, Ascend P6, Ascend Mate 2, P8 Lite, and SnapTo, all products said to infringe Ironworks patents.