Crossbow Dry-Fire Safety Latch Mechanism

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Solution Overview

Problem

Crossbows often suffer damage and pose a risk of injury due to dry-firing, where the bowstring is released without an arrow, leading to unintended release and potential injury or damage.

Innovation Solution

A dry-fire safety mechanism that includes a housing with a channel for the arrow, a trigger arm, a bowstring latch, and a dry-fire safety latch that prevents the bowstring from releasing when the trigger is actuated without an arrow, using a pivotally carried DFS latch to retain the bowstring in a cocked position and inhibit release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the trigger mechanism allows free actuation, then ease of operation is improved, but dry-firing causes damage and injury

Engineering Contradiction:

Improvetrigger actuationVSAvoiddamage and injury from dry-firing

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A dry-fire safety latch is introduced as an intermediary component between the trigger arm and bowstring latch. This mediator prevents direct bowstring release when no arrow is present, blocking the harmful effect while allowing normal operation when an arrow is properly inserted in the firing channel.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The dry-fire safety latch proactively prevents bowstring release before damage can occur. By requiring positive engagement with the bowstring latch before release is permitted, the system applies counter-action in advance to eliminate the possibility of dry-firing damage.

Inventive Principle:

Principle #9Preliminary anti-action

2Reliability

If a dry-fire safety mechanism is added, then safety and reliability are improved, but device complexity increases

Engineering Contradiction:

Improveprevention of dry-firingVSAvoidtrigger mechanism structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The dry-fire safety latch serves multiple functions: it acts as a safety barrier against dry-firing, a guide for arrow insertion, and a mechanical interlock for the trigger system. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The safety function is merged with the existing trigger mechanism structure. The dry-fire safety latch integrates with the housing and works in conjunction with existing components like the bowstring latch and trigger arm, combining safety features with operational mechanics rather than adding entirely separate systems.

Inventive Principle:

Principle #5Merging (Combining)

3Strength

If the bowstring is prevented from releasing during dry-firing, then durability and safety are improved, but the mechanism requires additional components

Engineering Contradiction:

Improvecrossbow durabilityVSAvoidnumber of latch components

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The trigger mechanism is segmented into distinct functional zones: the dry-fire safety latch occupies a specific region to block unintended release, while the bowstring latch and trigger arm maintain their own operational zones. This segmentation allows each component to perform its function efficiently without requiring excessive interconnections.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS9909832B2Dry-fire safety for crossbow

Publication Date: 2018.03.06 DARTON ARCHERY LLC

AI summary

A trigger mechanism for a crossbow that includes a housing having a channel for receiving an arrow, a trigger arm carried by the housing, a bowstring latch for retaining a bowstring in a cocked position that is pivotally carried by the housing and engagable with the trigger arm, and a dry-fire safety (DFS) latch pivotally carried by the housing and engagable with the bowstring latch, wherein the DFS latch substantially retains the bowstring latch in the cocked position when the trigger arm is actuated without the arrow seated in the channel.