This is a photo of a solid grooved spring shaft from a 10’x10′ door at a local bakery in Henderson. The door became obstructed when a pole was placed in the path of the door as it was closing. The motorized door stopped, but the motor kept running and the cables came unraveled and begin to wrap themselves around the shaft.
A few moments later the door went into a free-fall until it reached the extent of the unraveled cables. At that point, the forces were enough to bend the 1″ solid steel shaft!
Lesson: Garage doors can be hazardous even with professional care. Do not leave debris in the path of a closing door, and ALWAYS make sure someone watches the garage door as it is closing, all the way until it reaches the floor.