What is the use of cylinder lock?
Most deadbolts use a cylinder lock. In the cylinder lock, the key turns a cylinder, or plug, which turns an attached cam. When the plug is turned one way, the cam pulls in on the bolt and the door can open.
Why do car doors automatically lock when driving?
Modern automatic door locking is more of a safety feature to keep whats inside in and what is outside out. Kids might try to open doors. In that case, unlocked doors can be a problem. Worse, car jacking is becoming prevalent.