Crossbow Trigger Assembly Automatic Safety Mechanism

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Solution Overview

Problem

Conventional crossbows lack an automatic safety device, making them hazardous due to the risk of accidental discharge when the safety feature is not engaged by the user.

Innovation Solution

A trigger assembly with an automatic safety mechanism that engages when the bowstring is drawn, incorporating a safety pin, safety lock, and a pushing arm to prevent unintentional release of the bowstring, ensuring the crossbow cannot be fired unless the user intentionally releases the safety mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a manual safety device is added to a conventional crossbow, then safety is improved, but the device remains dangerous when the user forgets to engage the safety device

Engineering Contradiction:

ImprovesafetyVSAvoiduser dependency

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The safety device automatically engages when the bowstring is drawn and held in place by the catch, and automatically disengages when the bowstring is released. The system uses the movement of the bowstring and catch to drive the safety mechanism through the pushing arm, eliminating the need for manual user action to engage or disengage the safety feature.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The safety device is engaged in advance automatically when the bowstring is drawn, before the user intends to fire. The mechanism prepares the safe state by defaulting to locked position, and only becomes unfired when the user intentionally releases the trigger after the safety has already been engaged through the automatic mechanism.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If an automatic safety mechanism is implemented, then accidental discharges are prevented, but the device complexity increases

Engineering Contradiction:

Improveaccidental discharge preventionVSAvoidmechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The safety mechanism is merged with the existing trigger assembly components. The safety pin, safety lock, pushing arm, block, and string stop are integrated into the same housing and work in coordination with the trigger, bowstring catch, and bowstring. This unified design prevents accidental discharge while avoiding the need for a completely separate safety system.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The pushing arm serves multiple functions: it transfers movement from the bowstring catch to the safety lock, and also interacts with the block to control the safety mechanism. The block itself serves dual purposes by engaging with both the pushing arm and the string stop, coordinating multiple safety functions within a single component structure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS7588022B2Trigger assembly with a safety device for a crossbow

Publication Date: 2009.09.15 POE LANG ENTERPRISE

AI summary

A trigger assembly has a housing, a trigger, a string holder, a bowstring catch biasing member, a safety pin, a safety lock, a pushing arm, a block, a block biasing member and a string stop. The housing has a mouth. The trigger has a trigger element and an actuating lever combined with the trigger element by dovetailed recess and protrusion. The bowstring catch has a string hook and a leg selectively engaging the hook on the actuating lever. The safety pin is moveably mounted in the housing and is supported on the actuating lever. The safety lock is moveably mounted in the housing and has a push rod. The pushing arm has a protrusion abutting the push rod. The block has a transverse rod selectively engaging the front end of the pushing arm. Accordingly, a trigger assembly with two safety features is provided.