[Ned nyna 11]

Look closely at the ball/socket and you will see that a pin is stuck through it to keep it from popping open inadvertently. The pin is in line with the shaft and is in turn secured with a wire loop around the shaft.
So git a little screwdriver under the loop and pivot the loop and then pull the pin.
When the pin is out, the easy way to pop the ball/socket is by shoving a screwdriver between them and twisting.