I have a Paterson Super System 4 Auto Load Reel. It's supposed to be "Adjustable for film sizes: 35mm, 126, 127, 120/220" If came out of the box fully collapsed for 35mm (and works wonderfully at that setting). Here's the thing: I can't get it to expand to the larger settings. There doesn't seem to be any kind of catch or release. There were no instructions in or on the box. The only thing I can think of is to simply pull it apart to the wider settings, but when I try that nothing happens. I've pulled so hard I'm afraid of breaking it. Is there something I'm missing, some technique involved in expanding it?