Mechanical and gate for interlocking electric power switches and distibution system incorporating same

A mechanical AND gate (39) has a pivot plate (41) with an elongated slot (43) engaged by an output coupling (53) formed by a pair of pins (57) radially offset from the end of an output shaft (51). A pair of input couplings (45a,45b) secured to the pivot plate (41) at points laterally offset on opposite sides of the elongated slot (43) couple first and second elongated actuators (7712-7732) to the pivot plate (41). Movement of only one of the elongated actuators (7712-7732) to an ON position causes the pivot plate (41) to translate relative to the output coupling (53), but not to rotate. However, when the second actuator (7712-7732) is moved to an ON position in a direction parallel but opposite to the movement of the first actuator (7712-7732), the pivot plate (41) rotates to rotate the output coupling (53), and therefore, the output shaft (51). This mechanical AND gate (39) has particular application to interlocking three electric power switches (71-72) such as circuit breakers so that any two, but not all three, circuit breakers (71-72) may be on at one time.