I have the following setup, consisting of a bar attached to another bar via a ball joint (indicated by a circle, and attached to the wall over a pulley with a weight at the end (the small "kg" symbol). I want to pull on one side of the bar. This is sort of like a one-handed cable row at a gym.
Top view: Side view:
But when I pull, indicated by the black arrow, the angle (in red) between the force and the bar gets wider than the 90 degrees before the pull.
I thought of adding a blocking element:
But this would not help, as the pulley always aligns with the pulling force vector.
How can I pull, while keeping everything (the angle between the two bars, but at least the angle between the back bar and the force vector) at 90 degrees? I hope this makes sense. I am thinking about something between the two bars, such as a spring.