Card Reader Lock Mechanism Using Worm Gear for Phishing Prevention
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Solution Overview
Problem
Conventional card readers with large reduction gear trains for securing contact pressure with cards are prone to phishing attacks, as they allow criminals to separate the lock lever from the card using tools, and their size is increased due to the complex gear structure, even with small motors.
Innovation Solution
A card reader with a power transmission mechanism using a worm gear and helical gear, reducing the number of gears while increasing the reduction gear ratio, ensuring secure contact pressure with a small motor, and a lock mechanism that prevents the lock pawl from being moved by tools, thereby preventing card removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a reduction gear train with many gears is used to increase the reduction gear ratio, then contact pressure of the lock teeth with the card can be secured, but the size of the card lock mechanism becomes large
Solution Approach 1:
The patent combines multiple gear functions into a single integrated gear structure. The gear has both a first engagement portion that engages with the lock lever and a second engagement portion that engages with the card, merging what would traditionally require separate gears into one component. This reduces the overall size of the mechanism while maintaining the necessary reduction gear ratio for sufficient contact pressure.
2Volume of moving object
If a small motor is used to reduce the size of the card lock mechanism, then the mechanism size is reduced, but it becomes difficult to secure sufficient contact pressure with the card
Solution Approach 1:
By integrating both lock lever engagement and card engagement functions into a single gear, the system achieves a higher effective reduction gear ratio without requiring a larger motor. The combined gear structure multiplies the torque from the small motor more efficiently, ensuring sufficient contact pressure is achieved despite the reduced motor size.
3Ease of operation
If the lock lever is made easily movable to allow normal card ejection, then card ejection is facilitated, but criminals can use tools to separate the lock lever from the card during phishing attacks
Solution Approach 1:
The gear's engagement portions are designed with asymmetric characteristics. The first engagement portion with the lock lever allows movement in one direction for normal ejection, while the second engagement portion with the card provides resistance in the opposite direction. This asymmetric design enables legitimate card ejection while preventing tool-based separation attempts during phishing attacks.
Solution Approach 2:
Different portions of the gear have different engagement characteristics tailored to their specific functions. The first engagement portion is designed for smooth engagement and disengagement with the lock lever, while the second engagement portion is designed for firm, tool-resistant engagement with the card. This local differentiation of properties allows the system to satisfy both ease of operation and security requirements.
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 solution reduces the size of the card lock mechanism while effectively preventing phishing by maintaining contact pressure with the card and making it difficult for criminals to release the lock pawl, ensuring the card cannot be drawn from the reader.
Implementation Method 1
a power transmission mechanism structured to transmit power of the motor to the lock member, and including a worm gear structured of a screw gear and a helical gear engaged with the screw gear
Data Source
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AI summary
A card reader which is capable of reducing the size of the card lock mechanism and of surely preventing phishing is provided. The card reader includes a card lock mechanism 7 structured to prevent drawing of the card from the card insertion port when abnormality has been detected in conveyance of the card 2 in the card conveying passage W. The card lock mechanism 7 includes a motor 14, a lock member 15 which is formed with a prevention pawl 35a configured to contact with the card for preventing drawing of the card, and a power transmission mechanism 16 structured to transmit power of the motor 14 to the lock member 15. The lock member 15 is moved between a contact position where the prevention pawl 35a is contacted with the card and a retreated position where the prevention pawl 35a is retreated from the card conveying passage by power transmitted from the motor 14. The power transmission mechanism 16 includes a worm gear 20 structured of a screw gear 18 and a helical gear 19 engaged with the screw gear 18.