Windows

Looking for some information on the window catches , locks in my apartment. They are of a pull down slide at the side of the window which moves a "hooked" piece of metal out of the catch fixed to the frame.

I think that as you pull the slide down there is an allen screw that becomes visible which holds the hooked metal part in the lock. Am I correct? Has anyone any drawings , size etc of the allen screw as there does not seem to be any holding the hooked piece in place in one of my windows. Can anyone provide details where to buy replacemnets etc?

Thanks for your help.

regds
dd

There are lots of different types. I think I would take one or a photi of one to a local window company and if they don't have one I am sure they can point you in the right direction