Spring Loaded Metal Piece for Vinyl window

The first part to comes to mind is our 26-375. This works under the same kind of principle as your pivot bar. Carefully look it over and let me know what you think.

The 26-375 has a locking pin at the top that needs to be disengaged so that you can remove it. In some cases, you will need to unscrew the bottom rail of the sash itself and pull it away slightly from the glass so you can take out the pivot bar. Be very careful if you have to do this, as you don't want to damage the window itself.