Packard type shutter

[norman valentine]

I have a large shutter that is not a Packard but does the same job. When I bought it it arrived in several pieces, I have managed to reassmble it and it works on instantaneous and bulb. There is a mechanism that I cannot see how to make work nor can I see its purpose. It could be a booster spring to give a faster instantaneous speed.
On the front of the shutter is a two handled knob that you twist agaist spring pressure which is what makes me believe that is to adjust the shutter speed.
Is there anyone familiar with this shutter who could advise me?
Thanks, Norman

[TheDeardorffGuy]

That is an Ilexpo. Made by Ilex in the 20s-1960. (last listing I've seen.)
Wheres the box with the controls?

[cowanw]

try this thread
http://www.largeformatphotography.info/forum/showthread.php?t=42990

[norman valentine]

Yes that's my shutter. I don't have the box that goes on the front but have built it into my 10 x 8 camera that is almost complete. As I suspected the knob is to give a faster instantaneous speed. The thread suggested by Cowanw tells me all I need to know. Thank you everybody.
Norman