Lock Cylinder Key With Angled Recess Flanks
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Solution Overview
Problem
Existing key designs for lock cylinders face challenges in accommodating a large number of locking recesses on a limited key length, leading to difficulty in insertion and a limited number of locking codes, often resulting in pin tumbler jamming and reduced versatility.
Innovation Solution
The key features a locking recess with a deepest section having a smaller angle of inclination to the perpendicular than the flattest section, a middle section with a rounded contour transitioning smoothly to both, and pin tumblers arranged at an angle to the vertical, allowing for easy insertion and precise support, along with an asymmetrical design and non-round pin tips for enhanced locking codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If locking recesses have steep inclined flanks to reduce space requirements, then more locking recesses can be accommodated on a limited key length, but pin tumblers may jam during insertion
Solution Approach 1:
The locking recess flank is divided into three distinct sections: an upper section with a first angle of inclination, a middle section with a second (smaller) angle of inclination, and a lower section with a third angle of inclination. This segmentation allows each section to serve a specific function - the upper and lower sections provide the necessary locking geometry, while the middle section with its smaller angle reduces resistance and prevents pin tumbler jamming during insertion.
Solution Approach 2:
Different sections of the locking recess flank are given different local qualities through varying angles of inclination. The middle section specifically has a smaller angle (second angle) compared to the upper and lower sections, creating a localized region that reduces friction and resistance. This local modification allows the overall structure to maintain its locking functionality while preventing jamming in the critical insertion zone.
2Ease of operation
If concave rounded sliding surfaces are used to allow free key insertion, then ease of operation improves, but key length increases and fewer locking recesses can be arranged
Solution Approach 1:
Instead of using a single long concave rounded surface, the invention segments the flank into three sections with different inclination angles. The middle section with its smaller angle provides the necessary smoothing effect for easy insertion, while the compact angular design of all three sections together fits within a limited key length, allowing more locking recesses to be arranged.
Solution Approach 2:
The invention changes the geometric parameters of the flank by using different angles of inclination for different sections. The middle section uses a smaller second angle to reduce resistance during insertion, while the upper and lower sections use larger first and third angles to maintain compact dimensions. This parameter variation achieves both easy operation and limited key length.
3Adaptability or versatility
If locking recesses are arranged close together to increase the number of locking codes, then the number of locking codes increases, but pin tumblers may interfere with each other
Solution Approach 1:
The segmented flank design with three sections creates distinct interaction zones for adjacent pin tumblers. Each pin tumbler interacts primarily with its own locking recess, and the angular transitions between sections provide clear separation zones that prevent interference between adjacent pins, even when locking recesses are arranged close together.
Solution Approach 2:
The locking recess flank is designed asymmetrically with different angles for upper, middle, and lower sections. This asymmetric geometry creates unique interaction patterns for each pin tumbler, ensuring that adjacent pins do not interfere with each other's operation while allowing compact arrangement for increased number of locking codes.
Data Source
Figure 1~3
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Figure 6~8
AI summary
A key (8) for a lock cylinder (1) has convexly shaped flanks (15, 16) of a locking recess (12). The locking recess (12) serves to receive a tip of a pin (13) of a pin tumbler (5) arranged at an angle to the plane of a shaft (7) of the key (8). The key (8) can be inserted into the lock cylinder (1) particularly easily and allows for a large number of locking recesses (12) on a limited length of the shaft (7).