Here is an idea to research.
Back in the day they had roll up blinds, A piece of material rolled around a usually wooden tube with a spring inside.
One of the main problems was that sometimes the ratchet would not catch and if you did not have a firm grasp of the lower edge, which usually was a wooden slat inserted into a looped hem, it would snap up sharply whirling itself around the shaft and loose the return tension. You would then have to re-tension the blind so that it would work properly. Sometimes there were cord pulls attached to the lower slat using a thumb tack.
So,..... I can see this as being attached to the slat and being held in place with pressure of the 2 formed tabs and also provide a hole with which to attach a cord.
But, I see the pointed shape as being a preventative measure to stop the slat from revolving around the shaft, therefore stopping the loss of tension. It was this feature that probably made it a patatentable design.
Just a thought that might help research.