I'm working on a fixer-upper, and I needed to repair the screens. In order to remove the screens, I of course needed to lift the window all the way up. However, there was a bracket blocking the window's travel:
"No problem" I thought. But when I unscrewed that phillips screw, the rod just shot out of the frame. It sounded like a gunshot and took a chunk out of my hand. Same was true for the other side of the frame (though I was smart enough to wear gloves).
After the brackets came off, the rods moved freely back and forth. The window still opened and closed just fine, but it wouldn't stay up. It seems that the rods are under a lot of tension and hold the window in place when it's opened.
It seems that the rods can be screwed in. If I turn them counter-clockwise, the resistance builds up, and if I let go, they quickly spin back to their starting point. But after mucking around with them for a bit, it's not clear how to properly restore their function.
Here's what the right side of the top of the bottom window looks like where it meets the rod:
I'm definitely willing to read a manual if I can be pointed to it; I just haven't had any luck finding information about this type of window.
Best Answer
These are called spring balances, and have enough tension in the spring to hold the window open (sorry about your hand). It's kind of hard to tell from the pictures you posted what type they are (other than older ones), but you should be able to find some instructions for a model similar to yours now that you know what to search for.
In general, you'll want to attach them at the bottoms first and then lift up the sash to allow re-attaching the tops. This is a lot easier with 3 hands, so you might want to have someone hold the sash up or prop it if you can find something the right height.