A patent dispute between Lebanon-based Permobil and Sunrise Medical HHG intensified this week after Sunrise filed a lawsuit in federal court claiming that Permobil infringed on a patent for a motorized wheelchair.

More than a year ago, Permobil filed a lawsuit asking a judge to rule that Patent 394, owned by Sunrise, is invalid. Sunrise denied those claims and filed a counterclaim for patent infringement against Permobil, whose parent company is Swedish. The patent at issue is for a mid-wheel drive power wheelchair.

The lawsuit filed by Colorado-based Sunrise on Tuesday claims that Patent 556, which is directly related to Patent 394, also is being infringed upon by Permobil. Sunrise is asking the court for monetary damages and an injunction prohibiting Permobil from using the patent.

The trial regarding Patent 394 is set for Jan 15, 2013. 

Permobil's legal counsel had not returned a phone call as of noon Friday.