Obviousness

Obviousness Analysis of U.S. Patent No. 10,514,223 under 35 U.S.C. § 103

This analysis evaluates the obviousness of U.S. Patent 10,514,223, which claims a firearm trigger mechanism featuring a hammer-forced reset and a bolt carrier-actuated locking bar, potentially implemented as a drop-in module. The analysis considers combinations of the cited prior art references that a person having ordinary skill in the art (POSITA) would have been motivated to combine, leading to the claimed invention.

Claim 1: Core Trigger Mechanism

Claim 1 of US10514223 describes a trigger mechanism comprising:

1. A hammer with a sear notch, pivoting between set and released positions.
2. A trigger member with a sear, pivoting between set and released positions, having a surface contacted by the hammer (when the hammer is displaced by the bolt carrier) to force the trigger to the set position.
3. A locking bar pivotally mounted and spring-biased to block the trigger, moving against bias to unblock the trigger when contacted by the bolt carrier at a substantially in-battery position.

A POSITA would have found the mechanism of Claim 1 obvious by combining the teachings of US 2017/0219307 A1 (Fostech) and US 9,568,264 B2 (Graves).

• Fostech ('307 A1) explicitly discloses a trigger-locking mechanism, or locking member (analogous to the locking bar in '223), that prevents the trigger from being pulled until the bolt carrier is in battery. The locking member is disengaged by the forward movement of the bolt carrier, allowing the firearm to be fired. This directly addresses the functionality of elements 3 and 4 of Claim 1 regarding the locking bar's operation and interaction with the bolt carrier to prevent out-of-battery firing.
• Graves ('264 B2) teaches the fundamental concept of a "forced reset" mechanism that uses "rigid mechanical contact between the trigger and the gun bolt" to achieve a positive reset and increase the rate of fire. Graves also includes a feature where the trigger is blocked from being depressed until late in the operating cycle, preventing the hammer from falling before the bolt is in battery. This reference provides the core motivation for a forced reset and highlights the desirability of preventing premature hammer release.

Motivation for Combination and Modification:
A POSITA, aiming to combine the safety advantages of Fostech's bolt-carrier-actuated locking bar (preventing premature firing or "hammer follow") with the enhanced rate of fire provided by a forced-reset trigger as taught by Graves, would be motivated to integrate these two concepts. The '223 patent itself points out a limitation of Graves, noting it "does not provide a 'drop-in' solution for existing popular firearm platforms" and "would require not only a modified fire control mechanism, but also a modified bolt carrier." The '223 patent explicitly seeks to overcome this by using an "otherwise standard M16-pattern bolt carrier assembly."

To achieve a "drop-in" solution compatible with standard bolt carriers, a POSITA would be motivated to modify Graves's forced reset mechanism. Instead of the "gun bolt" directly contacting the trigger, it would be an obvious design choice to leverage the existing and "normal resetting of the hammer" by the bolt carrier. By modifying a surface on the trigger member to be contacted by the hammer's tail portion (or another suitable surface on the hammer) during its rearward, bolt-carrier-driven resetting movement, the trigger could be forced to its set position. This would achieve the forced-reset functionality in a mechanically efficient manner that integrates with existing component interactions and minimizes modifications to the standard bolt carrier, making the overall mechanism more suitable for retrofitting into existing firearm platforms. This modification, combining the forced reset concept from Graves with the mechanical interaction between the bolt carrier and hammer, would lead directly to the hammer-forced reset element of Claim 1.

Therefore, the combination of Fostech's bolt-carrier-actuated locking bar with a hammer-actuated forced reset (an obvious modification of Graves's forced reset to improve compatibility with standard components), would render Claim 1 obvious.

Claim 4: Drop-in Trigger Module

Claim 4 describes the mechanism of Claim 1 housed within a "drop-in" module, having transversely aligned pairs of openings for receiving hammer and trigger assembly pins, which are aligned with corresponding openings in the firearm receiver.

A POSITA would have found the subject matter of Claim 4 obvious by combining US 5,704,153 A (Colt's Manufacturing Company, Inc.) with the combination of references rendering Claim 1 obvious.

• Colt's ('153 A) clearly teaches the concept of a modular fire control system. This patent discloses a "drop-in" unit where the hammer, trigger, and other fire control components are pre-assembled within a single, self-contained housing, designed for easy installation into or removal from a firearm's receiver using standard pins.

Motivation for Combination:
The '223 patent explicitly states that its invention "is particularly adaptable for construction as a 'drop-in' replacement trigger module that only requires insertion of two assembly pins and the safety selector." A POSITA, having developed the functional trigger mechanism of Claim 1 (with the hammer-forced reset and bolt-carrier-actuated locking bar), and motivated by the stated objective of creating an easily retrofittable solution for popular firearm platforms, would find it obvious to package this mechanism within a modular "drop-in" housing. This engineering approach is well-established in the firearms industry for simplifying installation and offering aftermarket upgrades, as demonstrated by the Colt's '153 patent. Combining the functional mechanism of Claim 1 into a housing as taught by Colt's '153 would be a predictable and obvious design choice to achieve the benefits of modularity and ease of installation, thereby rendering Claim 4 obvious.