Levers 2 and 3, turning about fixed axes A and B, have slots b into which pin e of member 5 enters. The lift cage is suspended from the wire rope on eye a of tie-rod 4. Spring 1 is compressed. If the rope breaks, the spring is released, head f of tie-rod 4 pushes down member 5 and levers 2 and 3, turning about axes A and B, engage the interlocking device which stops the lift cage and keeps it from dropping.
$494$SL,S$