## Facts

- Valmont owned U.S. Reissue Patent No. Re. 31,838 covering a center-pivot irrigation system with an extension arm to water field corners outside the circle reached by a standard pivot irrigator.
- The patent claims included “means for moving” an extension arm relative to the main arm and “control means” to operate that movement as the main arm rotates.
- These elements were drafted in means-plus-function form under 35 U.S.C. § 112 ¶ 6, requiring claim coverage to be tied to the corresponding structures described in the specification and their statutory equivalents.
- The specification described a particular control arrangement using electrical signals and steering mechanisms on the irrigation structure to pivot the extension arm.
- Reinke sold a competing corner-watering system that achieved a similar corner-watering result but used a different control arrangement guided by signals from a buried electromagnetic cable.

## Issues

1. Whether the district court improperly found infringement of means-plus-function limitations by treating the claims as covering any system performing the claimed functions, rather than limiting them to the disclosed structures and § 112 ¶ 6 equivalents.
2. Whether Reinke’s buried-cable guidance system was a structural equivalent of the control and moving structures disclosed in the patent for purposes of § 112 ¶ 6 literal infringement.

## Decision

- The Federal Circuit reversed the district court’s finding of infringement as to claims containing means-plus-function limitations.
- The court held that the district court used an overly broad equivalency approach and failed to confine the “means” limitations to the patent’s disclosed structures and their § 112 ¶ 6 equivalents.
- Properly construed, Reinke’s buried-cable guidance architecture was not an equivalent of the specific control and steering structures disclosed in the specification, so Reinke did not literally infringe those means-plus-function claim elements.

## Legal Principles

- Means-plus-function claim language under 35 U.S.C. § 112 ¶ 6 is construed to cover only the corresponding structure, material, or acts described in the specification and equivalents thereof.
- A court must first identify the specification’s corresponding structure for each means-plus-function element and then assess whether the accused device uses the same or an equivalent structure, not merely whether it achieves the same overall function or result.
- “Equivalents” under § 112 ¶ 6 are structural equivalents tied to the disclosed means; this analysis is distinct from the doctrine of equivalents and does not permit expanding claim scope to any mechanism that performs the function.

## Conclusion

The Federal Circuit reversed the infringement judgment because the claims’ means-plus-function limitations could not be read broadly to cover any corner-watering control system; they were limited to the patent’s disclosed control and steering structures and their § 112 ¶ 6 structural equivalents, which did not include Reinke’s buried-cable guidance approach.


Valmont Indus., Inc. v. Reinke Mfg. Co., 983 F.2d 1039 (Fed. Cir. 1993)