Roller tube

The roller tube is the axle housed inside the shutter box that the curtain of slats rolls around as it goes up. On manual shutters it carries, at one end, the pulley that the strap winds onto.

The top slat is attached to the roller tube with clips. When those clips break, the shutter comes loose and drops all the way down. Other typical faults are a roller tube that has come out of its brackets or a loose pulley.

On the coast the salt air rusts the brackets and metal axles over the years, and the turn becomes stiff. If you notice the shutter going up in jerks or making a noise inside the box, it is worth having it checked before it drops. We do this in shutter repair.