NST Global v. Sig Sauer: Helpful Reminders About Claim Preambles And Claim Construction At The PTAB

• Published date: 06 June 2023
• Subject Matter: Intellectual Property, Litigation, Mediation & Arbitration, Patent, Trials & Appeals & Compensation
• Law Firm: Baker Botts
• Author: Mr Derek J. Langdon

Claim construction decisions do not always proceed as predicted by either party, and IPR proceedings can be particularly unpredictable when it comes to construing claim terms. A recent petition for writ of certiorari to the Supreme Court, in NST Global v. Sig Sauer, provides helpful reminders regarding claim construction and limiting preambles.

History of the Case:

Plaintiff NST Global invented a firearm accessory, the "Stabilizing Brace", that allowed users to stabilize the use of a handgun by stabilizing the forearm of the user.¹ NST Global was granted two patents on the invention.² Defendant Sig Sauer obtained a license to the patents as the exclusive distributor for several years, but after the agreement ended, Sig Sauer developed its own brace.³ NST Global filed an infringement lawsuit against Sig Sauer.⁴ Sig Sauer subsequently filed two IPR Petitions against the patents, and the infringement suit was stayed.⁵ The PTAB instituted both IPRs and ultimately found certain claims patentable and certain claims unpatentable. In the Final Written Decisions, one of the reasons the PTAB found certain claims unpatentable was based on construing a preamble to be limiting.⁶ Both parties appealed to the Federal Circuit, and after oral argument, the Federal Circuit issued a Rule 36 affirmance of the PTAB's decision.⁷ NST Global filed a petition for a writ of certiorari to the Supreme Court which is currently pending before the Court.

Issues Raised:

The petition raises two primary issues: 1) what is the proper standard for construing patent claim preambles? and 2) what constitutes notice or a waiver of arguments for the PTAB to construe a claim in its Final Written Decision without argument from one or both parties? Both parties' positions on these issues will be discussed further below, as well as how they may affect decision making during patent prosecution and litigation proceedings.

1. Construing Preambles as Limiting:

In the Final Written Decisions, the PTAB found certain claims of NST's patents have preambles that are limiting on the claims.⁸ The claims of the patent recite:

"A forearm-gripping stabilizing attachment for a handgun, the handgun having a support structure extending rearwardly from the rear end of the handgun, the forearm-gripping stabilizing attachment, comprising:"⁹

The PTAB's construction found "a handgun" and "a support structure ..." as "essential structure", "necessary to give life, meaning, and vitality to the claims," and therefore the...