Cylinder Lock Driver Pin Geometry for Stable Short-Pin Insertion
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Solution Overview
Problem
Conventional cylinder locks face issues with driver pin toppling over due to reduced length and misalignment between pinholes in the outer and inner cylinders, which complicates insertion and rotation.
Innovation Solution
The cylinder lock design features driver pins with varying diameters, where the outer cylinder diameter is larger than the inner cylinder diameter, and includes a posture maintaining region and communication region to prevent toppling and accommodate misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the total length of the driver pin is shortened to downsize the cylinder lock, then the space-saving and cost reduction goals are achieved, but the driver pin may topple over inside the pinhole due to insufficient length
Solution Approach 1:
The driver pin employs an asymmetric diameter design where the diameter at the outer cylinder side is larger than the diameter at the inner cylinder side. This asymmetric configuration provides a larger base diameter (1.2-1.5mm) at the outer cylinder end to prevent toppling, while maintaining a smaller diameter (0.8-1.0mm) at the inner cylinder end to facilitate insertion through misaligned pinholes. The asymmetric geometry resolves the contradiction by optimizing different sections of the same component for different functional requirements.
Solution Approach 2:
Different sections of the driver pin are given different diameters to fulfill different functional requirements. The outer cylinder side has a larger diameter specifically for stability and preventing toppling, while the inner cylinder side has a smaller diameter specifically for ease of insertion. This local differentiation of geometric properties allows the shortened driver pin to simultaneously achieve both stability and insertability.
2Reliability
If the clearance between the driver pin and the pinhole is narrowed to prevent toppling, then the driver pin stability is improved, but the driver pin cannot be inserted due to misalignment between the pinhole of the outer cylinder and the pinhole of the inner cylinder
Solution Approach 1:
The asymmetric diameter design directly addresses the insertion difficulty caused by misalignment. The smaller diameter section at the inner cylinder side creates sufficient clearance to accommodate misalignment between the two pinholes, enabling smooth insertion. Meanwhile, the larger diameter section at the outer cylinder side provides the necessary stability to prevent toppling once inserted.
Solution Approach 2:
The driver pin applies local quality differentiation by having different diameters at different locations. The local clearance created by the smaller diameter at the inner cylinder end accommodates misalignment, while the local stability provided by the larger diameter at the outer cylinder end prevents toppling. This localized optimization resolves the contradiction between insertability and stability.
Data Source
AI summary
A cylinder lock is disclosed that is capable of preventing a driver pin from falling over inside a pin hole even when the driver pin has been shortened. The cylinder lock comprises an outer cylinder and an inner cylinder that rotatably fits into the outer cylinder. The outer cylinder and the inner cylinder each have a hole formed therein which connects to a key hole and into which the driver pin can be inserted. The diameter of the outer cylinder side of the driver pin is greater than the diameter of the inner cylinder side of the driver pin. An orientation-maintaining region having a prescribed length in the axial direction and a fixed diameter is preferably provided at the outer cylinder-side end of the driver pin.