Automatic brakes for elevator car

A system for automatically braking an elevator car (1), said system comprising

• brake means (12, 13) on the car (10) which operate when said car reaches or exceeds an allowable speed limit in response to movement inside an elevator shaft;
• a control cable (60) suspended vertically in said elevator shaft;
• stop means (40) mounted on said car (10), said stop means comprising at least two pulleys (41, 42, 42a, 42b) having circumferential grooves, said control cable (60) passing through said grooves,
• one of said pulleys (41) being a stop pulley (41), control means responsive to a speed of rotation of said stop pulley being less than a threshold speed of rotation, for enabling said stop pulley to turn freely at the same time that said car (10) moves inside said elevator shaft, and said control means locking said stop pulley when its speed of rotation is equal to or greater than said threshold speed of rotation,
• another of said pulleys (42, 42a, 42b) being loose pulleys, at least one of said loose pulleys being responsive and reacting to the movement of said car (10) when said stop pulley (41) is locked, said other pulley moving relative to said car and in a direction substantially parallel to the direction of said car (10), and
• control means (11) for applying said brakes (12, 13) when said other loose pulley (42, 42a, 42b) moves relative to said car (10).