In a hinge mechanism, a first hinge portion and a second hinge portion are urged toward predetermined angular relationships relative to one another. A force, directed outwardly from the first hinge portion, is applied by an axle pivotally connecting the first and second hinge portions and having a V-shaped tip against a V-shaped groove in the second hinge portion, urging the V-shaped tip and groove to engage. In addition to being urged toward predetermined angular relationships, the first and second hinge portions are kept in predetermined angular relationships until a torsional force is applied to one of the hinge portions to overcome forces keeping the V-shaped tip and groove in engagement.