Ashley's #1408... is a sort of symmetric butterfly
This is
obviously true, I guess...
...whichever collar surrounds the loaded end will be kept from tightening around the nub by the tension on the SPart --holding the collar open--;
but the collar around an unloaded end can be draw tight around the nub and be jammed
! ( I was
surprized by the
clarity by which this
general statement is expressed - three rare events, at once ! )
