Never really thought about why the ball has a flat spot on top,
but now in noodling it...it must have to do with releasing the ball
from the complimentary formed sheetmetal glob of the coupler.
After posting those images (repeated'm below)...noticed that the coupler glob
did NOT circumvent the whole ball, but stopped at the top.
The latch when engaged...completes the 360* glob on top and below (critical)
the equator.
This then captures the ball and an interference for it keeping it from coming
out as long as the latch is in place & engaged.
Wonder even more how the forces will do to the latch mechanism over
time. Especially since the images shows a cantilevered latch system
that is held mainly at the coupler formed sheet metal at the top on
the first two images. The 3rd image shows some cross rods and wonder
how they are captured.
This one shows what am talking about best. See how the latch has to move out
of the way to then allow the ball to move rearwards in order to come out...but...
that is exactly the direction this new hitch places all of it's
forces. But then, this image also shows a 'top' on the ball covering
that flat spot...or is just missing the lines of the diagram?
Another thought is that the flat spot is to allow or make sure the
ball goes in all the way. If there is something there, like pebble,
would that then allow the latch to close, but the ball is not fully
captured?
Yet another thought is that the flat spot allows the ball to get 'up
there' far enough while not in place. To then slide forward to make
the complimentary coupler glob. Then the latch closes it to circumvent
the ball.
This also says the coupler glob is oblong or straight on the sides to
allow the ball to move backwards and out of the glob that tightly
holds the ball
John's image here looks like the sided are straight and not curved
Some one want to mix up some epoxy and top off the flat spot of the
ball and then try to install & latch it? :)
Also thought that this would be best, as it is, on lighter trailers,
but after a couple of comments that the tongue and coupler would/might
be of lighter material...says this would not be a candidate on that
lighter coupler latch (assumption that it is lighter duty)