At the present time, lifts used in civil engineering constructions have not provided safety, since a sudden breakage of either any gearing or their winch shaft can cause their quick free fall, reaching the ground at a very high speed. In these circumstances, it is not always possible to activate an emergency brake. In the face of that situation, a large number of that kind of lift accidents have been occurring.

This request refers to a probable device to solve this problem by bringing into action an automatic brake, which performs independently of the other components of the winch, as soon as the lift reaches a specific speed. Due to this independence, the automatic brake is effective in any ofthe following situations:

• motor shaft breakage,

• reducer gate shaft breakage;

• pulley shaft breakage; • coupling breakage;

• bearing breakage;

• gearing breakage;

• electric circuit defect;

• electro-magnet brake failure.

The automatic brake, the focus of this request, is illustrated by figures which complete this report:

• Figure 1 - View in perspective ofthe winch, standing out the position ofthe s automatic brake;

• Figure 2 - Exploded view ofthe automatic brake;

• Figure 3 - Schematic view ofthe system with deactivated brake;

• Figure 4 - Schematic view ofthe system with activated brake.

The numerical sequence of figures, as well as throughout this report, refers to 0 the following components:

1. reducer bearing cover

2. screen

3. pulley

4. keys 5 5. pulley shaft

6. screw thread

7. set flange of locks

8. threaded hole

9. set pin of spring 20 10. synchronizer

11.fitting pin of connecting-rod 12. cotter pin 13. locks

14. lock hole

15. fitting pin of connecting-rod

16. set pin of spring

17. locks connecting-rod 18. spring

19. hinge bush

20. set screw of bush

2 Mock ring

22. bearing 23. brake drum

24.teeth

25. lock ring

26. sealing cover

27. spring lockwasher 28. et screw

29 band

30 brake lining

31. rivet

32.screw 33. nut

34. bush 35. washer 36.cotter pin

37. chassis 38 band shaft 39. set support of band 40 set slot of band This device is basically composed of two elements: a braking system and a drum brake. Both of them form a single closed train connected to the pulley shaft of the winch, according to the description below.

For this safety system of winches, it is necessary to place the reducer cover (1) which works as a pulley shaft (5) bearing. The cover has a "neck" (2) that works as a pulley (3) screen in case the shaft breaks, avoiding that the pulley moves in the space between the reducer and the pulley and gets loose.

The braking system is composed basically of the following elements: a flange (7) fitted into the pulley shaft (5) and set by a key (4); a synchronizer (10) ofthe locks motion fitted onto the flange (7), and one or more locks (13) connected to the synchronizer by connecting-rods (17). Connecting-rods (17) are two holes plates, being one of the holes fitted onto the synchronizer (10) pin (1 l)and the other, onto the lock (13) pin (15); cotter pins (12) are placed to guarantee that connecting-rods (17) are indeed set to pins.

Locks (13) have a hole (14) through which a bush (19) passes. A screw (20) is inserted into each bush (19) and threaded through the flange (7) hole (8), setting bushes (19) in it. In this way, bushes (19) work as a centrifugal stroke shaft of locks (13). A spring (18) is set by one end to a pin (9) on the flange (7) and by the other end, to a pin (16) on a lock.

Then, fitting the braking train, it is set by the lock ring (21) into the bearing (22) ofthe brake drum (23). The drum (23) has some teeth (24) regularly spaced at its internal end. After

fitting the braking train to the brake drum, both are set by a lock ring (25) to each other, forming a closed train in which the braking train rotates, but the drum does not, if the train is in normal position (deactivated brake). A cover (26) completes this train and is set by a screw (28) in the thread (6) ofthe pulley shaft (5). The brake lining (30) is set by rivets (31) to a metal band (29). The band (29) has a bush (34) at one of its ends by which it is fitted into a shaft (38) welded on the winch chassis (37), being set by a cotter pin (36). At the other end of the band (29), a screw (32) is set and inserted into the slot (40) of the support (39) on the chassis (37), being the band (29) opening adjusted by nuts (33) on the screw (32). The winch is in its normal working (Figure 3) when the braking train and the shaft (5) inside the drum (23) bearing rotate together, but the drum (23) does not move.

By the spring (18) stress, it is possible to find out the speed (pulley revolution on its shaft, per minute) at which the automatic brake is activated. But, obviously, this speed must be higher than the normal one ofthe winch operation. Should any gearing or the shaft breaks, and the pulley reaches a speed previously determined, the centrifugal force performance hurls the locks (13) "out", fitting them onto the teeth (24) (Figure 4). From this fitting, the drum (23) and the train shaft-pulley- flange-locks, to which it is locked, start rotating together. By rotating, it occurs a friction berween the brake lining (30) and the drum (23), being the latter braked. Therefore, the whole train is braked, avoiding the lift fall. Depending on the adjust ofthe band (29) pressure, the lift stops immediately or goes down smoothly a few meters till stopping.

By being in a opposite position in relation to the reducer, the automatic brake can work independently of the other components of the winch, what guarantees its

effectiveness if any of them break down, except, of course, the steel cable. In this way, it is possible to avoid almost of all lift accidents.

Although the above description seems to be an ideal way, changes might be introduced by replacing one or more components which have the same technical function, but keeping the patent scope. One possible change is the use of different numbers of locks (one or more than two).

Even though it has been designed at first for winches of lifts used in constructions, the use of the automatic brake can be extended to various kinds of winches, elevators, foundry traveler, among other products for which it can be useful.