Rekeyable Lock Pin-Rack Curved Engagement
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Solution Overview
Problem
Existing rekeyable lock cylinders face limitations in increasing the number of bitting positions without compromising the strength of small components, which affects security and key variation.
Innovation Solution
The design incorporates a pin-rack engagement feature with increased grooves and semi-cylindrical surfaces to maximize bitting positions, allowing for seven or more bitting positions while maintaining component strength through complementary engagement surfaces and reduced sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the size of engaging components is reduced to allow increased variation in key bitting, then the number of bitting positions is increased, but the strength of the small components is compromised
Solution Approach 1:
The rack includes a curved engagement surface that contacts the key follower. This curved geometry allows for multiple bitting positions while maintaining adequate contact area and strength. The curvature enables the rack to engage with key followers at different positions along the engagement surface, increasing bitting variation without compromising the structural integrity of the reduced-size components.
Solution Approach 2:
The engagement interface transitions from a simple linear or point contact to a curved surface contact, adding a dimensional aspect to the engagement. This curved engagement surface in three-dimensional space allows for multiple bitting positions to be achieved through variation in the engagement location along the curve, rather than requiring increased linear dimensions.
2Reliability
If the number of bitting positions is increased to maximize security, then the number of bitting combinations is increased, but the complexity of the lock mechanism is increased
Solution Approach 1:
The rack is designed as a universal component that handles multiple functions: it provides the engagement interface for key followers, enables multiple bitting positions through its curved surface, and maintains mechanical strength. This multi-functional design increases security through multiple bitting positions without proportionally increasing overall mechanism complexity.
Solution Approach 2:
The curved engagement surface of the rack changes the geometric parameters of the interaction between the rack and key follower. By varying the contact point along the curved surface, multiple bitting positions are achieved through parameter variation (angular position along the curve) rather than through additional mechanical components or complex mechanisms.
3Adaptability or versatility
If the components are made smaller to increase key variation, then the number of recognized bitting positions is increased, but the contact surface area is reduced
Solution Approach 1:
The curved engagement surface of the rack provides extended contact area compared to a flat or point contact. The arc of the curved surface allows for distributed contact over a portion of the rack's width, maintaining adequate contact surface area even when the overall component size is reduced. This curved geometry effectively increases the functional contact area relative to the component dimensions.
Data Source
AI summary
A rekeyable lock cylinder with a cylinder body and a plug assembly. The lock cylinder includes a plurality of key followers and a corresponding plurality of racks disposed in the plug assembly. Disengaging the racks from the key followers allows rekeying of the lock cylinder.