## Facts

- H.H. Robertson Co. owned U.S. Patent No. 3,721,051 covering a concrete deck sub-assembly used to form an underfloor electrical cable trench.
- Robertson sued United Steel Deck, Inc. and Nicholas J. Bouras, Inc. (affiliated entities) alleging inducement and contributory infringement of multiple claims through their composite steel deck structures.
- Robertson argued the accused structures were the same or substantially the same as products previously found to infringe the same patent in earlier litigation that also upheld the patent’s validity and enforceability.
- The district court held a four-day evidentiary hearing with expert testimony and prior-art evidence, including three prior-art references not addressed in the earlier litigation.
- The district court granted a preliminary injunction barring defendants, pending trial, from making, using, or selling the accused structures.
- Defendants appealed, disputing the district court’s findings on likelihood of success (validity and infringement), irreparable harm, and the balance of equities.

## Issues

1. Whether the district court clearly erred in finding a reasonable likelihood that the patent would withstand validity challenges, including challenges based on new prior art.
2. Whether the district court clearly erred in finding a reasonable likelihood of infringement by the accused structures.
3. Whether the district court properly presumed irreparable harm upon finding a strong likelihood of success on validity and infringement.
4. Whether the district court abused its discretion in weighing hardships and the public interest and issuing a preliminary injunction.

## Decision

- The Federal Circuit affirmed the preliminary injunction.
- The court held the district court did not clearly err in finding a reasonable likelihood of success on validity and infringement.
- The court held the district court acted within its discretion in presuming irreparable harm based on the strong merits showing.
- The court held the balance of hardships and public interest supported maintaining the injunction pending final adjudication.

## Legal Principles

- A preliminary injunction decision is reviewed for abuse of discretion; underlying factual findings are reviewed for clear error.
- The preliminary-injunction factors in patent cases (likelihood of success, irreparable harm, balance of hardships, and public interest) are weighed together rather than treated as rigid, independent requirements.
- A prior judicial determination upholding the same patent’s validity (and finding infringement) is a relevant consideration supporting likelihood of success in a later case against different defendants, provided the court evaluates the current record and any new evidence, including new prior art.
- The presence of additional prior-art references does not require denial of preliminary relief if the district court considers them and reasonably finds they do not raise a substantial question undermining validity.
- Where a patentee makes a strong showing of likely validity and infringement, irreparable harm may be presumed, reflecting the difficulty of fully compensating loss of exclusivity and competitive injury with money damages.
- In weighing hardships, harm to an accused infringer from being enjoined from likely infringing activity generally carries less weight than harm to a patentee from continued infringement of a likely valid patent right.

## Conclusion

The Federal Circuit sustained preliminary injunctive relief where the patentee showed a strong likelihood of success on validity and infringement, the district court considered newly presented prior art without finding a substantial challenge to validity, and the court treated the earlier validity adjudication as persuasive support for likelihood of success while presuming irreparable harm and finding the equities and public interest favored protecting the patent right pending trial.


H.H. Robertson Co. v. United Steel Deck, Inc., 820 F.2d 384 (Fed. Cir. 1987)