US US9151557

An analysis of United States Patent US9151557 B2 is provided below.

Title: Automatic sear assembly for a rifle

Assignee: Sig Sauer Inc.

Inventor: William C. Daley, Jr.

Filing Date: May 13, 2014

Issue Date: October 6, 2015

Abstract:
The patent describes an automatic sear assembly designed to provide full-automatic and/or burst firing capabilities to large-bore rifles. The assembly features an automatic sear and a sear lever with bidirectional articulation. This allows the rotational movement of the sear lever away from the automatic sear to have no effect, while its movement toward the sear causes it to trip. This mechanism harnesses the force of the rifle's moving bolt carrier to initiate subsequent firing cycles without needing to release and pull the trigger again.

Plain-Language Overview of Independent Claims:

Claim 1: This claim outlines the fundamental design of an automatic sear assembly. It consists of four main components that rotate on a single axis:

• An automatic sear that connects to the rifle's safe/fire selector and hammer.
• A sear lever positioned behind the automatic sear and extending above it.
• A first spring that pushes the sear lever against the back of the automatic sear.
• A second spring that connects the assembly to the safe/fire selector switch.

The key function described is that when the sear lever is pushed in one direction (e.g., by the rearward motion of the bolt carrier), it moves away from the sear without causing any action. However, when it's pushed in the opposite direction (e.g., by the forward motion of the bolt carrier), it forces the automatic sear to rotate, which in turn releases the hammer to fire a round. This creates the mechanism for automatic fire.

Claim 16: This claim also describes an automatic sear assembly but focuses more on the geometric and functional relationship of its parts. It details:

• An automatic sear that pivots and has an "actuating portion" with two parts extending in opposite directions from the pivot point.
• A sear lever that pivots on the same axis but moves independently. It extends further in one direction than the corresponding part of the sear.
• A first spring that keeps the sear lever pressed against the sear.
• A second spring that applies a rotational force to the sear, controlled by the safe/fire selector switch.

This arrangement allows the sear lever to trip the sear when moved by the rifle's action, but only when the selector switch has placed the sear in the correct position for automatic fire.

Claim 20: This claim provides a very specific and detailed description of the components in the automatic sear assembly:

• An automatic sear and an adjacent sear lever as described in the other claims.
• The first spring is identified as a helical torsion spring.
• The second spring is identified as a helical double-torsion spring with a specific design, including two sets of coils and two "legs," one for interfacing with the selector switch and one for anchoring.
• It further specifies a bushing and a pin that create the axis of rotation. The bushing has a slot, and the pin has a groove that aligns with the slot to hold the anchoring leg of the second spring in place.

This claim essentially describes a complete and specific embodiment of the invention, detailing not just the main parts but also their specific forms and how they are assembled and retained within the firearm.

Litigation Status:

As of April 26, 2026, a search of the U.S. Court of Appeals for the Federal Circuit (CAFC) dockets for the year 2026 shows no records of litigation involving US Patent 9,151,557. I am unable to access information about cases that may be in lower courts or that may have been filed before or after 2026.