Crossbow Security Unit with Automatic Locking Mechanism

Solution Overview

Problem

Existing crossbows lack automatic security units that are activated during bolt loading, leading to potential accidental bolt projection, posing risks to users and others, as these units are not automatically engaged and can be forgotten by users.

Innovation Solution

A crossbow design featuring a supporting unit, a bow, a string-pulling unit, a trigger unit, and security units with a lock, lock-biasing spring, and pusher mechanism that automatically locks the trigger until the bolt is properly loaded, preventing accidental bolt projection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a security unit is provided in the crossbow, then the safety of the user and nearby people is improved, but the device complexity increases

Engineering Contradiction:

ImprovesafetyVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The security unit is automatically activated during the bolt loading process before the crossbow is ready for use. The lock is preliminarily positioned to restrain the trigger unit, and the pusher is preliminarily positioned to maintain the lock in the restraining position, ensuring safety is established before the user needs to operate the crossbow.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The security unit operates automatically without requiring user intervention. The lock-biasing spring automatically returns the lock to the locking position after the pusher releases it, and the entire sequence occurs without the user needing to manually activate or monitor the security mechanism, reducing operational complexity while maintaining reliability.

Inventive Principle:

Principle #25Self-service

2Device complexity

If the security unit is manually activated by the user, then the device complexity is reduced, but the reliability decreases because the user may forget to activate it

Engineering Contradiction:

Improvedevice complexityVSAvoidsafety

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The security unit is automatically activated during the bolt loading process before the crossbow is ready for use. The lock is preliminarily positioned to restrain the trigger unit, and the pusher is preliminarily positioned to maintain the lock in the restraining position, ensuring safety is established before the user needs to operate the crossbow.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system provides automatic feedback through the lock-biasing spring that continuously monitors and maintains the lock in the appropriate position. When the pusher releases the lock, the spring immediately provides feedback by returning the lock to the locking position, ensuring the security mechanism remains reliably engaged without user intervention.

Inventive Principle:

Principle #23Feedback

3Reliability

If the lock is restrained by the pusher during the entire loading process, then the reliability is improved, but the ease of operation decreases

Engineering Contradiction:

ImprovesafetyVSAvoidease of operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The restraining mechanism is dynamic rather than static. The pusher is positioned to restrain the lock during the loading process, but when the bolt is properly loaded and the user needs to operate the crossbow, the pusher moves to release the lock, allowing the lock-biasing spring to return the lock to its restraining position. This dynamic transition ensures both reliability during loading and ease of operation during use.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The security unit is automatically activated during the bolt loading process before the crossbow is ready for use. The lock is preliminarily positioned to restrain the trigger unit, and the pusher is preliminarily positioned to maintain the lock in the restraining position, ensuring safety is established before the user needs to operate the crossbow.

Inventive Principle:

Principle #10Preliminary action

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

Ensures the crossbow remains locked until the bolt is fully loaded, enhancing user and bystander safety by preventing unintended bolt discharge during the loading process.

Implementation Method 1

The lock-biasing spring is inserted in the sight and adapted for pivoting the lock to the locking position

Methodology Applied

Scientific EffectSpring: Spring

Implementation Method 2

The pusher is connected to the string-pulling unit and hence movable relative to the supporting between two positions through the unlocking window

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentUS9766032B1Multiply secured crossbow

Publication Date: 2017.09.19 COMBIS SPORT ENTERPRISE CO LTD

AI summary

A crossbow includes a supporting unit, a bow, a string-pulling unit, a trigger unit, a sight and a security unit. The security unit includes a lock, a lock-biasing spring and a pusher. The sight includes an unlocking window. The lock is movable in the sight corresponding to the unlocking window between a locking position and an unlocking position. In the unlocking position, the lock prevents the trigger unit from pivoting. The lock-biasing spring is inserted in the sight and adapted for pivoting the lock to the locking position. The pusher is connected to the string-pulling unit and hence movable relative to the supporting between two positions through the unlocking window. In the first position, the pusher keeps the lock in the unlocking position. In the second position, the pusher allows the lock-biasing spring to move the lock to the locking position.