Hello Everyone, Welcome back to Motion Monday 👋 This week we’re taking a look inside one of the most common mechanisms we use every day but rarely think about — the Pin Tumbler Lock. A lock looks simple from the outside… but inside, a tiny positioning problem decides whether it opens or stays completely blocked. For this model, I used a 5-pin Pin Tumbler design, where each pin stack consists of: • Key Pins → variable lengths based on key geometry |
No Key Inserted
Without a key inserted, the pins sit across the shear line and physically prevent the plug from rotating.
Key Inserted
As the correct key enters, each cut on the key lifts a pin stack by a different amount. Only when all five pin interfaces align exactly at the shear line does the plug gain freedom to rotate.
One pin too high? Locked.
One pin too low? Locked.
All five aligned? Rotation unlocked.
Motion is allowed only when every condition is satisfied.
Thanks For Reading! What everyday mechanism should we break down next?
To Play with the motion yourself you can download SOLIDWORKS file from below.
| 3DPlay Model | Model Zip |
|
