FORTUNE — Given its miserable track record in patent battles with Apple (AAPL), Samsung’s legal team must have taken great solace in Dyson Ltd’s decision to drop the patent infringement suit it filed against the company in September.
At issue was the steering mechanism in the “Motion Sync” vacuum cleaner that Samsung introduced at a Berlin consumer electronics show last summer. Sir James Dyson declared it a “cynical rip-off” of a patented feature in Dyson’s DC cylinder vacuums.
Samsung had documentation to show it had been working its steering mechanism for more than a year, and the Dyson suit was dismissed on Nov. 21, 2013 — the same day a California jury ordered Samsung to pay Apple another $290 million for iPhone patent infringements.
Now Samsung has turned the tables, according to the
, and is suing Dyson for “intolerable” litigation that has “seriously hurt its corporate image.”
Declaring that it is taking “a hard-line stance against patent trolls that use litigations as a marketing tool,” Samsung is asking for 10 billion won ($9.4 million) in damages.
This is not the first time the two companies have locked horns over vacuum cleaner technology. In 2009 Britain’s High Court ordered Samsung to suck it up and pay Dyson $850,000 for infringing Dyson’s “triple cyclone” patents.
UPDATE: Dyson’s official statement:
“Dyson pioneered cyclonic vacuum cleaners and digital motors – and has been developing them ever since. We patent our technology, and naturally defend it. It is surprising that a company over 100 times bigger than Dyson is so worried. The patent system offers us some protection, but not enough: with an army of lawyers, hidden prior art is occasionally found and ways to design around existing patents identified.”