A fluid coupler comprises a ball valve a through hole provided between a female
coupler body and a valve holding casing connected to the female coupler body and
surrounding the ball. The ball valve has a first flat sliding surface formed on
a spherical outer surface of the ball valve which extends in a direction normal
to a rotational axis of the ball valve, and a flat stop surface raised from the
first flat sliding surface and reaching said spherical outer surface of said ball
valve, the first flat sliding surface and the flat stop surface together defining
a recess. The valve holding casing has an alignment portion formed on and raised
from an interior surface thereof. The alignment portion has a second flat sliding
surface slidably engaged with said first flat sliding surface. The flat stop surface
is adapted to engage with the alignment portion to limit the rotational movement
of the ball valve.
