On 17/08/2016 11:09, tim... wrote:

wrote in message
...
On Sunday, 14 August 2016 21:05:26 UTC+1, Yvonne wrote:
Is there some mechanism that can be attached that will allow one to
raise
the lower sash to different levels- depending on how much fresh air is
required, and then lock it in the selected position?

https://www.locksonline.co.uk/Window...h-Windows.html



even after watching the video, I still don't get how it works?

Anyone help?

tim




Its just a spring loaded bolt that sits in the top sash above the bottom
sash and stops either of them sliding past the other until you put the
key in and push the bolt in.
It locks automatically when you close the window.