There may be one or more adjustment screws that control the amount of lateral travel allowed and the spring tension.

First raise the door fully to release all spring tension.

Both manual and automatic garage doors operate on spring tension.

It was under spring tension and returned to its original rearward position.

The bolt has to be held back under spring tension before you can pull the trigger and make it go off.

Cables must be the same length in order for the spring tension on both sides of the door to be equal.

The spring tension will increase as the two fluid elements move further apart and the process runs away.

Or did they really balance the spring tension perfectly against the weight of the lower case?

This concept allows release angle to be independent of spring tension.

This builds spring tension, that is released at the peak of every complete turn in the "S" pattern.