Electric switching device

An electric switch that automatically opens when the voltage carried by the switch falls below a predetermined value comprising, in combination,

• a switching element linearly movable along the direction of its longitudinal axis between a cut-in position that closes the switch and a cut-out position that opens the switch and is biased toward its cut-out position,
• control means having an electromagnet electrically connected in series with the switch,
• a release lever actuated by said control means to move from a first position to a second position when the voltage energizing said electromagnet falls below said predetermined value,
• a blocking mechanism operating with said release lever and said switching element to move from a blocking position in which it maintains the switching element in said cut-in position to a release position in which it allows said switching element to move to said cut-out position in response to said release lever moving from said first position to said second position, and
• a selector shaft and a first toggle lever acting independently of the blocking mechanism and operatively connecting said selector shaft and said switching element to drive said switching element between said cut-out and cut-in positions in response to a rotation of said selector shaft, said first toggle lever being near its dead center position when said switching element is in its cut-in position.