stump-studded swamps. Previously, marsh craft of this type were suited only for hauling equipment through open marshes, frequently broke down, and required the use of huge timber mats (“matting”) to support earthmovers in order to clear away tree stumps when it was necessary to venture into the swamps. The marsh craft developed by Rivet was structurally stronger and more watertight than earlier marsh craft, and was capable of traversing stump-dotted swampland without matting or preclearing.
Robert J. Wilson, Sr., learned the design details of the Rivet pontoon when he worked for Rivet during 1974 as a contract welder. After completion of his welding contract with Rivet, Wilson began building Rivet-type pontoons for defendant Wilco Marsh Buggies and Draglines, Inc., a corporation formed and owned by his three sons, defendants-appellants John M. Wilson, Sr., Dean R. Wilson, and Robert J. Wilson, Jr. Wilco bought a Rivet craft, obtained a copy of the ’785 patent, and began making and selling a vehicle strikingly similar to the Rivet amphibious marsh craft manufactured by Kori.
Rivet, Woodson, and Kori filed this suit against Wilco and the Wilson brothers, seeking injunctive relief and damages for patent infringement. The district court issued separate decisions on the issues of liability and damages. In its liability decision, the district court held that the ’785 patent was valid and infringed, and that the defendants, by actively inducing infringement of the ’785 patent, were liable as infringers. 561 F.Supp. at 521-22. The Fifth Circuit affirmed on June 27, 1983.
Decision Below
After its initial decision on liability, the district court issued its separate memorandum opinion on damages on August 30, 1982, deciding four issues: pecuniary damages, prejudgment interest, attorney fees, and exemplary damages. 561 F.Supp. at 523, 217 USPQ at 1302.
The district court awarded Kori pecuniary damages of $516,803.30, calculating damages on the basis of profits lost because of defendants’ sales of infringing units for use outside the United States and profits lost on rental of infringing units within the United States. Lost profits were calculated at $379,497, based on defendants’ sale of six machines. The court also determined that lost rental profits amounted to $137,311.30, based on the defendants’ profits for 4850 hours rental at a profit of $28.31 per hour.
The district court concluded that prejudgment interest should not be awarded because the record was not clear with regard to the date or dates from which interest should run. However, the court noted that it would consider the fact that plaintiffs should be compensated for the delay in receiving the lost profits owed to them in determining whether to impose exemplary damages. The court also awarded plaintiffs $50,000.00 in attorney fees and $28,-943.51 in costs.
Finally, pursuant to 35 U.S.C. § 284, the district court doubled the pecuniary damage award to $1,033,616.60. The court found that defendants willfully and deliberately infringed, having copied the essential parts of the amphibious craft, knowing it to be patented, and having no good faith belief that the patent was invalid. The court noted that the defendants willfully copied the invention of the ’785 patent without soliciting the advice of counsel, and only sought the advice of a qualified patent attorney after plaintiffs had brought suit to enforce the patent. In determining the amount of exemplary damages, the court considered the fact that the actual pecuniary damages it had calculated were not “sufficient to fully compensate plaintiffs,” and included the portion of damages which the court found it had been unable to determine exactly, including prejudgment interest.
OPINION
In pertinent part, 35 U.S.C. § 284 provides that “the court shall award the claimant damages adequate to compensate for the infringement but in no event less than