I used to have one of these - to overlap one curtain over another at the centre.
Nothing but trouble - caused no end of problems.
At the end in desperation I took the rail down and did away with the overlap gizmo - this was one I had made myself from stainless steel - the original having long since snapped.
From then on the curtains draw and open like oiled silk as smooth as warm butter on freshly baked bread.
My curtains no longer overlap - they just butt together.
The weight of the curtains caused the overlap runner to be pulled down and pivot in its channel - one end down and the other end upwards - this caused running friction which tended to cause the system to jam up.
Our house is much better without it as is my personal disposition. Not only that I no longer have to climb up to the rail to release the overlap thing.
Peccavi, April 2013
