Levers 1 and 2 turn independently of each other about fixed axis A . Lever 1 has lug c and lever 2 has lug a . I f lever 1 i s turned clockwise, lever 2 is stationary because lug a abuts against fixed stop b. If lever 1 is turned counterclockwise, lever 2 is turned by lug c and the two levers turn as a single link. In the free state, the levers are returned by spring 3 in the first case, and by spring 4 in the second to the position shown in the drawing.
$141$SL,L$