Mechanical locking differential lockout mechanism

A differential gear mechanism comprising a gear case defining a gear chamber, a differential gear set disposed in said gear chamber, and including at least one input gear and a pair of output gears defining an axis of rotation;

• a lock-up clutch operable to retard differentiating action, and actuating means for actuating said lock-up clutch;
• said lock-up clutch being operable between an engaged condition, effective to retard relative rotation between said gear case and said output gears, and a disengaged condition;
• said actuating means including cam means operable to effect said engaged condition of said lock-up clutch, and retarding means operable to engage said cam means and retard rotation of one member of said cam means, said retarding means comprising a flyweight mechanism rotatable about an axis oriented generally parallel to said axis of rotation, at a speed generally representative of the extent of said differentiating action, and defining a stop surface moveable from a retracted position to an extended position in response to a predetermined extent of differentiating action;
• said actuating means further including a latch surface disposed to engage said stop surface when said stop surface is in said extended position;
• characterized by:
• (a) a lockout mechanism operably associated with said flyweight mechanism and including a lockout member positionable, in response to an input signal, in a normal condition and a lockout condition;
• (b) in said normal condition, said lockout member permits said stop surface to move from said retracted position to said extended position;
• and
• (c) in said lockout condition, said lockout member prevents said stop surface from moving from said retracted position to said extended position.