Double-Bitted Reversible Key Plug Lock Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing plug key locks lack ease of use, sufficient pick resistance, and simple plug interchangeability, and are not easily replaceable, limiting their effectiveness and versatility.
Innovation Solution
A plug key lock design featuring a barrel with multiple longitudinal splines and a plug with alternating spring pockets and tumbler slots, allowing for independent biasing of tumblers and interaction with keys to change the lock's orientation, incorporating a reversible key mechanism that increases pick resistance and allows for plug removal without requiring specific key combinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional plug key locks are designed with simple tumblers and springs, then the device complexity is reduced, but the pick resistance decreases
Solution Approach 1:
The plug is divided into multiple segments including alternating spring pockets and tumbler slots, with multiple tumblers (first, second, and retaining tumblers) positioned at different locations. This segmentation allows each tumbler to be independently controlled by key lands, creating a more complex picking challenge while maintaining manageable device structure
Solution Approach 2:
Different regions of the plug have different functions: spring pockets provide biasing forces in alternating directions, tumbler slots accommodate movable tumblers, and specific locations have retaining mechanisms. This local differentiation of properties enhances pick resistance without requiring uniform complexity throughout the entire device
2Adaptability or versatility
If the lock uses fixed plug design, then manufacturing precision is improved, but plug interchangeability decreases
Solution Approach 1:
The plug is designed as a separable component that can be removed from the barrel and replaced with different plugs. Each plug contains standardized spring pockets, tumbler slots, and retaining mechanisms that can accommodate different tumbler configurations, enabling interchangeability while maintaining consistent manufacturing tolerances through standardized interfaces
Solution Approach 2:
The plug design incorporates universal features including standardized spring pockets that can hold different spring configurations, multiple tumbler slots that can accommodate various tumbler arrangements, and a retaining mechanism that works with different plug types. This universality allows a single barrel to accept multiple interchangeable plugs with different security configurations
3Ease of operation
If the lock requires specific key combinations for plug removal, then security is improved, but ease of operation decreases
Solution Approach 1:
The retaining tumbler is automatically actuated by the second key through the tumbler slot mechanism. When the second key is inserted and rotated, its profile automatically moves the retaining tumbler out of the retaining spline, enabling plug removal without requiring additional steps or combinations. The system serves itself by using the key's natural rotation to trigger the release mechanism
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 design enhances ease of use, increases pick resistance, and facilitates simple plug interchangeability, making the lock more secure and versatile, requiring professional tools for picking and allowing for compact construction with multiple combinations.
Implementation Method 1
A spring is mounted in each spring pocket between the bottom wall and a respective tumbler arm for biasing the tumbler radially outwardly
Data Source
AI summary
A lock has a locked condition and an unlocked condition comprising a barrel with a circular bore having three splines. A cylindrical plug is adapted to reside in the bore. First, second and retaining tumblers are positioned in tumbler slots, with the first and retaining tumblers biased in one direction toward the first spline and the second tumbler biased in the opposite direction into the second spline. When a first key is inserted, the first and second tumblers are moved against the bias so they retract from the respective splines and the plug can be rotated from the locked and unlocked conditions. When a second key is inserted while in the unlocked condition, the first, second and retaining tumblers are moved so the respective tumblers are either positioned in the third longitudinal spline or fully retained in the plug and the plug can be retracted axially from the barrel.