Volvo vs. Mercruiser Patent Case

Volvo Duo-Prop vs. Brunswick
Mercruiser Bravo-Three Patent Case

This page details the fight between the Mercruiser Dual Propeller Bravo-Three and the Volvo Duo-Prop. The actual fight was over patent Volvo #4,741,670, or more properly - over its reissued version as Re.#34,011. The basic facts were that : Reissued patents are done when an error has been made in publishing the patent. Sometimes an important word such as NOT is left out and drastically changes the meaning of a sentence. Patents can also be reissued when the inventor forgot to put something in that they meant to put in. Reissued patents rarely are allowed to broaden the claims of the original patent. Only about 1/3 of 1% of all patents get reissued and a small percentage of them have broadened claims. You must file for reissue within 2 years of the issue of the patent if the claims are being broadened. In this situation Volvo asked for a quite unusual amount of changes including broadening of claims in the patent and did it on the very last day of the 2 year period in which they could request a broadening reissue.

After the original patent was issued, Mercruiser designed the Bravo-Three propeller configuration to specifically avoid the Volvo patent and went into production. Then sometime later (July 1992) the Volvo patent was reissued and the broadened the claims in the area of propeller parameters to include the area Mercruiser was operating in (or at least Volvo said it did). If the reissued patent is valid and everybody agrees on the facts, the attorney's call this situation, Intervening Rights. The actual law on who is right, wrong and how to handle the issue has changed several times during the life of the patent system. Under current law, the situation is to go to court and the court is to determine the outcome. The court is to make sure the company that invested money and efforts to legally produce a product during the "Intervening" time between the patent and its reissue has opportunity to recover its investment. The results are somewhere on a sliding scale from the company being forced to get all the units back they ever made and destroying them, or convert them to non-interfering units, through being able to sell what it has already sold, sell all it currently has made, sell all it currently has parts to assemble, to manufacturing and selling more in the future. Some kind of licensing agreement is often reached. Very few cases have been tried in recent years in this particular doctrine. Typically companies try to get the patent or reissue declared invalid, or claim they are not infringing.

In real life, and in this case, often the alleged infringer will counter-suit the company claiming infringement claiming their patent is invalid. It is usually much better to be on the prosecution side. The prosecution drives the case. You get to direct the trial and to pick the venue (site to be sued in), while the company being sued is stuck to responding to the issues you bring up. You "yank their chain" which is more fun than having your chain yanked.

If the results are ever published (and I doubt that), they might make a nice legal brief in the patent textbooks.

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