Homework 7: April 4 Karch

BRIEF: In favor of Honeywell

The patent under discussion was obtained by Honeywell in 1982 for a technology that controls airflow surges in an auxillary power unit (APU) using inlet guide vanes (IGV). It has been determined in the courts that Sundstrand did not not infringe on Honeywell’s patent for two main reasons:

1. At the time of application for patent, Honeywell revised and narrowed its claims in order to be valid relative to prior art. This action concedes the use of the Doctrine of Equivalents, as if the Doctrine cannot be used to determine Honeywell’s patent invalid, Honeywell cannot use the Doctrine of Equivalents to determine that Sundstrand infringed.
2. Sundstrand used the IGV technology for an additional purpose to what Honeywell’s claims lay out. Due to the speed in which Sundstrand implemented this additional purpose from the time Sundstrand first started using the technology, this use was foreseeable, and should have been included in Honeywell’s patent in order to determine infringement.

Both of these points should be found to be faulty. The concept of history estoppel is to prevent parties from using conflicting arguments in court at different times relating to the same thing. While Honeywell did surrender some equivalents through the action of revising and narrowing its claims, this does not mean Honeywell surrendered any and all uses of the Doctrine of Equivalents. Both versions of the Honeywell patent included the IGV use to control surge, which is the central issue as far as infringement by Sundstrand, and this claim was not ammended or restricted at any time. Honeywell should not be able to use the Doctrine of Equivalents for every claim, as some of them were changed from the original patent, but for the claim at issue, the Doctrine is still valid, and should not be blocked by estoppel.

Sundstrand claims their additional use of IGVs to be foreseeable in nature, but this use did not occur until nearly a decade after the Honeywell patent was issued. If this use was foreseeable, this substantial amount of time would not have passed before Sundstrand or anyone else used IGVs in this fashion. Sundstrand used much the same system to accomplish a substantially similar goal in a substantially similar way, with an added step to what the Honeywell patent lays out, making Sundstrand’s invention dependent on the Honeywell patent, meaning Sundstrand infringed. Additionally, Sundstrand previously contended that their invention was unique, which would imply unforseeability.

Because of the above issues, we contend that Sundstrand did infringe on the Honeywell patent.