venetian blind clamp

I do not know if anyone has this annoying problem with windows that tip to open...

when the window is tipped, it becomes impossible to close it without you fingers getting caught in the vanes of the blind.So you must always use two hands to open and close the window when the blinds are down.

I made this clamp to solve all that nonsense   (OK it is too late for my blind as the vanes are already looking like a bird with a broken wing but they wont get any worse)

maybe it will help someone else.

it is designed for a 20mm diameter handle... and it just snaps into place