Sliding Locking Bar for Forced Reset Trigger

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Solution Overview

Problem

In firearms, particularly AR-pattern models, tolerance stacking issues can lead to imprecise actuation contact between the bolt carrier and locking bar, affecting the functionality of forced reset semiautomatic triggers, as existing designs often rely on pivotal motion which may not adequately compensate for dimensional variations in modular components.

Innovation Solution

A sliding locking bar mechanism is introduced, guided by a guide rod and housed within a receiver, allowing for linear movement and adjustable configurations to compensate for tolerance stacking, with a spring bias that blocks the trigger until the bolt carrier returns to the in-battery position, enabling user-controlled release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pivotal locking bar mechanism is used, then the trigger can block movement until the bolt carrier returns to battery position, but tolerance stacking issues cause imprecise actuation contact between the bolt carrier and locking bar

Engineering Contradiction:

Improvetrigger actuation reliabilityVSAvoidactuation contact precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The locking bar is changed from a pivotal motion mechanism to a sliding linear motion mechanism. The locking bar now slides along the guide rod in a straight line rather than pivoting, which provides more consistent and predictable motion that is less sensitive to tolerance variations in the assembly.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

A guide rod is introduced as an intermediary component to guide the locking bar's motion. The guide rod ensures that the locking bar moves precisely in the intended linear path and provides a stable reference surface for the bolt carrier to actuate the locking bar, compensating for tolerance stacking in the overall assembly.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If a sliding locking bar mechanism with guide rod is used, then actuation precision is improved, but device complexity increases

Engineering Contradiction:

Improveactuation contact precisionVSAvoidtrigger mechanism complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The guide rod serves multiple functions: it guides the locking bar's linear motion, provides a precise actuation surface for the bolt carrier, and acts as a reference feature for assembly. By combining these functions into a single component, the overall device complexity is minimized while achieving the desired precision.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If the locking bar is spring biased to a blocking position, then the trigger is securely blocked until in-battery position is reached, but the spring force may cause inconsistent release timing

Engineering Contradiction:

Improvetrigger blocking reliabilityVSAvoidtrigger release timing consistency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The mechanism transitions from relying on spring force to achieve locking to using direct mechanical engagement. The bolt carrier directly actsuates the locking bar by contacting it when in battery, replacing the indirect spring-based timing mechanism with a direct mechanical action that is less sensitive to spring force variations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The sliding locking bar mechanism ensures reliable trigger actuation and adjustable configurations, enhancing the precision and reliability of the trigger mechanism by preventing rotation and tipping, thus improving the firearm's performance across varying component tolerances.

Implementation Method 1

A locking bar is slidably mounted in a frame or housing and is spring biased toward a first position in which the locking bar mechanically blocks the trigger member from moving to the released position

Methodology Applied

Scientific EffectSpring bias: Spring

Implementation Method 2

A locking bar is slidably mounted in a frame or housing

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS11346627B1Forced reset semiautomatic trigger with sliding blocking bar

Publication Date: 2022.05.31 ABC IP LLC

AI summary

Provided is a trigger mechanism for a firearm having a receiver with a fire control mechanism pocket and a bolt carrier that reciprocates to pivotally displace a hammer when cycled. It includes a hammer having a sear notch and mounted in the fire control mechanism pocket to pivot on a transverse axis between set and released positions. A trigger member has a sear and is mounted in the fire control mechanism pocket to pivot on a transverse axis between set and released positions. The trigger member has a first surface positioned to be forcibly contacted by the hammer when the hammer is displaced by cycling of the bolt carrier, the contact causing at least in part the trigger member to be forced to the set position. A locking bar is slideably mounted in a support frame and spring biased toward a first position in which the locking bar mechanically blocks the trigger member from moving to the released position, and is movable against the spring bias to a second position when contacted by the bolt carrier reaching a substantially in-battery position, allowing the trigger member to be moved by an external force to the released position.