on the pivot it has some writing. pat pend. 1523 1478 and a large R with 1888 next to it.
this pivot is a right angle with a small square pivot sticking out of it. two holes on the bottom and one hole on the side of the sash.

You have an old Harvey brand pivot bar that hasn't been made in many years. The products mentioned in this thread are our best and only options, though unfortunately none of them are a guarantee. I apologize for the inconvenience.