Antitheft Device Needle Locking Mechanism

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Solution Overview

Problem

Existing anti-theft devices for securing items in self-service settings are not effective due to ease of mechanical force-induced release, allowing thieves to bypass alarms and remove the devices.

Innovation Solution

An anti-theft device with a needle mechanism that moves between engaged and disengaged positions, utilizing nested cages and a spring system with locking balls to secure the needle, and a keyhole-shaped slot to prevent unauthorized withdrawal, combined with a shock absorber to prevent accidental release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a spring-biased rod with a movable flyweight is used for locking, then the device can be released with a specific tool, but the locking is not effective against mechanical force and can be opened by controlled blows

Engineering Contradiction:
Improverelease with specific toolVSAvoidresistance to forced opening
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces the traditional mechanical spring-biased flyweight system with a magnetic locking system. The needle is retained in the engaged position by magnetic attraction between the needle and the housing, eliminating the mechanical flyweight that can be dislodged by blows. The release is achieved by detecting a specific pattern (e.g., RFID tag, barcode) that triggers the magnetic release mechanism, providing both security against forced opening and controlled release capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of the locking mechanism from mechanical force-based (spring pressure on flyweight) to magnetic force-based. This parameter change makes the system resistant to mechanical blows that cannot overcome the magnetic hold, while allowing electronic/optical detection methods to trigger release, thus resolving the contradiction between ease of authorized operation and resistance to forced entry.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a metal ring with a notch and flyweight is used, then the device can block passage, but it is easy to exert mechanical force to force release of the notch

Engineering Contradiction:
Improveblocking capabilityVSAvoidvulnerability to mechanical force
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical notch-flyweight interaction with a magnetic coupling system. The needle extends through the housing and is held by magnetic attraction, creating a blocking capability that is not vulnerable to mechanical leverage or blows. The magnetic field provides distributed holding force along the needle length rather than a single mechanical contact point, eliminating the weak point that thieves can exploit with levers or blows.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If a simple locking mechanism is used, then the device structure is simple, but it allows easy removal by thieves

Engineering Contradiction:
Improvestructure simplicityVSAvoidtheft prevention
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent integrates multiple functions into a single unified system: the needle serves as both the locking element and the detection target, the housing provides both structural support and magnetic retention, and the detection system handles both authentication and release triggering. This multi-functionality maintains relative structural simplicity while achieving high security through the integration of magnetic retention and electronic/optical detection, preventing theft without requiring complex multi-component mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enhances the security of self-service items by making it difficult to forcibly release the device, while allowing authorized removal using a specific unlocker, thus effectively preventing theft and false alarms.

Implementation Method 1

a spring pushing the needle into the retracted position

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

The locking mechanism is constituted by a magnetic latch blocking or releasing a notch formed on the metal ring

Methodology Applied
Scientific EffectMagnetic latch: Magnetism

Data Source

PatentEP3102760B1Antitheft device intended to be attached to an item on general sale
Publication Date: 2018.04.04 FORS FRANCE
  • EP3102760B1 patent drawingFigure 1
  • EP3102760B1 patent drawingFigure 2~3
  • EP3102760B1 patent drawingFigure 4~5

AI summary

Antitheft device intended to be attached to an item on general sale, comprising a ring (2), one of the ends of which is fixed to a rigid body (1) and the free other end of which is configured to allow it to be introduced into a complementary cavity formed in said rigid body (1), said body (1) comprising a mechanism for locking the free end in the body (1) when this free end is introduced into said cavity, said locking mechanism being made up of a needle (14) able to move at right angles to the direction in which said free end is introduced into said cavity, between a direction in which it passes through a complementary slot (8) formed in said free end, and a retracted position in which it leaves said free end free to move.