An apparatus for an actuating mechanism comprises a first member having a first axis; the first member has a generally spherical surface on a first half of the first axis and a generally ellipsoidal surface on a second half of the first axis. The first member is rotatable around a centerpoint of the first axis. A second member has a second axis and a generally ellipsoidal surface. The second member matingly engages the first member at the first member ellipsoidal surface and has a torsion spring coupled to the second member. The first member is actuated manually to move the second member. The torsion spring torque increases as the first member is rotated.

An actuation mechanism for a valve comprises a first member having a generally spherical surface on a first side of a bisecting line and a generally ellipsoidal surface on a second side of the bisecting line. The first member is rotatable around a central point of the bisecting line. The valve has a second member with a truncated ellipsoidal surface on both sides of a bisecting line. The second member matingly engages the first member at the first member ellipsoidal surface. The valve also includes a longitudinal member coupled to the second member and a biasing member coupled to the longitudinal member. The first member is rotated around the central point from a first position to a second position to move the second member and the longitudinal member linearly. The biasing member returns the first member and second member to the first position upon release of the first member.