"Staking Claims," Professionally Speaking, January 2003

PROFESSIONALLY SPEAKING

staking claims

A patent may cover more than it says.

by John C. Linderman

Recent changes in the laws and procedures involving patent claims increase the significance of an inventor's experience in the patent application process. The inventor's insight and know-how play a critical role in the procurement of a patent broad enough to cover alternative designs of similar products. Patent attorneys try to foresee alternatives, but inventors are generally more familiar with the art and the feasibility of potential near-copies.

Every application for a patent contains a technical disclosure of the invention, including patent claims—verbal descriptions or definitions setting out the essential elements of an invention. For example, if the inventor of the dumbbell had patented the device, the first claim in the patent might have read as follows:

"A muscle enhancing exercise device comprising: an elongated bar having a first end and an opposite second end, and at least one hand gripping area located between the first and second ends; a first weight connected to the first end of the elongated bar; and a second weight connected to the second end of the elongated bar; the first and second weights being connected to the bar at locations on opposite sides of the hand gripping area so as to allow the exercise device to be lifted and lowered with one or more hands."

Patent disputes often arise over the interpretation of claims. For example, while the claim for the dumbbell seems clear at first blush, does it cover one made as an integral casting of the bar and the weights?

The rules, or doctrines, governing claim interpretation are numerous and often so nebulous that they can lead to different results. Rulings by trial judges are often reversed on appeal.

One claim-interpreting rule that is popular with inventors and patent owners is the doctrine of equivalents, which allows the claim of a patent to be expanded beyond its literal wording. Under the doctrine, the dumbbell claim might be expanded to cover a device having springs anchored to the floor in place of weights.

The doctrine of equivalents was briefly discarded for all but a few situations by the Court of Appeals for the Federal Circuit in a case entitled Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co. This court in Washington hears patent appeals, and its decisions tend to shape patent law.

Last May, however, the U.S. Supreme Court overruled the Appeals Court decision and confirmed the propriety of using the doctrine of equivalents. The Supreme Court also established guidelines imposing significant burdens on the patent owner whose claims were amended during prosecution of the patent.

Claims in issued patents often result from amendments. Initial claims are drafted to be broad in scope, and patent examiners are inclined to reject them. Amendments make claims more specific. For example, suppose the inventor of the dumbbell had filed a claim for "a bar with a load generator on each end." The patent examiner might reject the claim because it could apply to a pry bar. The inventor would amend the broadly worded claim by submitting a more limited description.

There would be little doubt that the competitor who used springs instead of weights would have infringed the broad claim. But what about the amended claim?

The Supreme Court's decision in the Festo case said that, in order to invoke the doctrine of equivalents after a claim has been amended, the patent owner must show that the equivalent was "unforeseeable at the time of the amendment." This burden makes the inventor's experience critical. The inventor might very well have foreseen the spring-operated exercise device as an alternative. The inventor should tell the patent attorney.

The attorney then would be armed with information that would suggest an amended claim that relied upon both the inventor's design and the competitor's alternative.

The Supreme Court has confirmed the doctrine of equivalents. However, the court also imposed the burden on the patent owner to establish the right to expand the literal scope of patent claim. The inventor can make a significant contribution to the procurement of a comprehensive patent on the invention beyond the technical disclosure.

John C. Linderman, a senior partner with the intellectual property law firm of McCormick, Paulding & Huber LLP in Hartford, Conn., received his undergraduate degree in mechanical engineering from MIT.