Crash bar
（重定向自Panic hardware）
A crash bar (also known as a panic bar, exit device, panic device, or a push bar) is a device for unlocking a door during emergency conditions. The mechanism consists of a spring-loaded metal bar fixed horizontally to the inside of an outward-opening door. When the lever is either pushed or depressed, it activates a mechanism which unlatches the door allowing occupants to leave quickly from the building.