Key Tip Flat End Face for Lock Cylinder Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Double locking cylinders often fail to actuate reliably due to wear and tear on the key tip, causing the lock cylinder to spin as the cylinder core can be turned with the key, but the lock bit is not coupled, leading to unreliable operation and potential need for key and lock cylinder replacement.
Innovation Solution
Designing the key tip with a flat, orthogonal end face that maintains surface contact with the lock cylinder's coupling element, preventing wear-induced shortening of the key shank and ensuring consistent operation by maintaining the shank length and insertion depth over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the key tip is rounded (conventional design), then the key can be easily manufactured and inserted, but the key shank shortens due to wear, causing the lock cylinder to spin and unreliable operation
Solution Approach 1:
The key tip geometry is changed from a rounded surface to a flat end face with specific dimensional parameters (height of 5-35% of key shank height, orthogonal orientation to axial direction). This parameter change transforms the contact from line/point contact to surface contact, fundamentally altering the wear characteristics and maintaining key shank length over time.
2Reliability
If the key tip is rounded (conventional design), then manufacturing is simple, but wear causes the coupling element to become insufficiently actuated, leading to lock cylinder spinning
Solution Approach 1:
The contact surface area is increased by changing the key tip from rounded to flat with orthogonal end face. This parameter change distributes wear across a larger surface area, reducing the rate of material loss and maintaining sufficient actuation force on the coupling element throughout the key's service life.
3Reliability
If the end face height is too small, then the key structure remains simple, but wear effects significantly reduce the shank length and displacement of coupling element
Solution Approach 1:
The end face height is optimized to 5-35% of the key shank height at the end facing the key bow. This specific parameter range provides sufficient surface area for reliable coupling element actuation while maintaining a simple key structure that is easy to manufacture and insert.
Data Source
Figure 1
Figure 2a~2c
AI summary
A key (10) for a locking cylinder (100), with a key bow (12) and a key shaft (16) extending away from the key bow (12) along an axial direction (14), wherein the key shaft (16) has a key tip (18) formed in the same material as the key shaft (16), is designed and further developed in such a way as to enable permanently reliable operation of locking cylinders using simple design means, that the key tip (18) has an end face (22) formed as a plane which is oriented orthogonally to the axial direction (14).