This is a quick and dirty vector diagram of how I see it working
Even if there is NOT slop (tolerance) in the coupler to ball...there will be over
time.
Then the wear of the friction material will allow the tapered shank to tilt
back and forth over time.
So in pulling the chain, it pushes the tongue against the ball via
where I say the pawl is. That then creates the same lever arm most
all other WD systems look like.
Then the TV pulls and the ball wants to go towards the coupler front
(away from the pawl). Then does the ball bang back and forth inside
the coupler?
{edit}...ops...put the bushing on the wrong side of the tongue bracket, but
think you guys know what I meant.
It is really difficult to see how it truly works without detailed
cross section diagrams or exploded assembly diagram
Go Brady !!!...home town kid just up the street from me