Combination Padlock Clutch Geometry to Obscure False Gate Feedback
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Solution Overview
Problem
Existing combination padlocks, such as those described in U.S. Pat. No. 7,117,698, provide false clicking sounds and feedback that reduce the number of digits an intruder needs to determine, making it easier to pick the lock.
Innovation Solution
A padlock design featuring clutches with equal-length extended-fins and rounded or sloped edges to obscure false gates, bolts with different radii and slopes, and a cam mechanism to minimize audible feedback, thereby increasing picking and decoding time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If extended fins of different lengths are used in the clutch, then the lock can provide clear feedback for correct gate alignment, but false clicking sounds and feedback are generated that reduce the number of digits an intruder needs to determine
Solution Approach 1:
The patent applies asymmetry by using extended fins of different lengths (first extended fin longer than second and third, second and third equal length) to create distinct feedback patterns. This asymmetric design allows the correct gate alignment to produce a specific, recognizable feedback sequence while false alignments produce different, non-matching feedback patterns, enabling the user to identify the correct combination without generating misleading clicks that would reveal gate positions to intruders.
Solution Approach 2:
The patent implements a feedback mechanism where the extended fins of different lengths interact with corresponding gates to produce distinct clicking sounds or tactile feedback only when all fins are correctly aligned with their respective gates. This feedback system provides clear confirmation of correct gate alignment to the authorized user while the specific pattern of feedback (with varying click intensities or sequences due to different fin lengths) prevents intruders from easily determining which digits correspond to which gates, thereby losing information about gate positions.
2Device complexity
If traditional clutch design is used, then the padlock structure is simple, but the padlock is vulnerable to picking and decoding
Solution Approach 1:
The patent applies local quality by modifying specific properties of the clutch components - the extended fins have different lengths and the clutch body has specific geometric features (angles, curvature) at localized positions. These localized modifications create unique interaction patterns with the gates that provide anti-picking security through complex feedback sequences, while the overall clutch structure remains relatively simple and integrated into the existing padlock mechanism.
Data Source
AI summary
A padlock including a lock body, a combination mechanism to control movement of a spindle within the lock body, at least one clutch mounted about the spindle each clutch having at least one extended-fin, and alignment of each of the at least one extended-fin with a corresponding gate in the lock body allows for movement of the spindle within the lock body. The padlock may also include a shackle having a long leg and a short leg, and the padlock is positionable between a locked mode in which the short leg of the shackle is positioned within the body and the movement of the spindle within the lock body is substantially limited, and an unlocked mode in which the short leg of the shackle is spaced apart from the body and movement of the spindle within the lock body is allowed.