PROBLEM W/ Pull Down Attic Stairs

I have pull down attic stairs. Lately, I have trouble getting them to go back up into the ceiling. It appears that the two jointed metal arms (1 on each side) are going past 180 degrees, with the elbow bent toward the stairs, and not allowing the stairs to fold up into the ceiling. If I yank on the two arms, and extend the elbows past 180 degrees away from the stairs, then I can get the stairs to go back up into the ceiling. I have encountered this problem with several sets of pull-down stairs, so I assume this is a common problem.

DOES ANYONE HAVE A SOLUTION?