Braking system and passenger boarding bridge

1. A braking system for a passenger boarding bridge that comprises a tunnel having a cabin, a cab and a rotationally driving device that comprises a driving motor mounted on the cab, a driving wheel mounted on an output shaft of the driving motor, and two driven wheels mounted on the tunnel and one drive belt being in cooperation with the driving wheels and the driven wheels, and having two ends fixed on the cabin respectively, wherein the braking system comprises:

a locking member fixedly mounted on the cabin;

at least one set of braking assemblies, each of which comprises an oscillating member rotatably mounted on the cab, an oscillating wheel mounted on the oscillating member and an elastic member, wherein the elastic member presents a pre-tightening force, the oscillating wheel cooperates with an outer side of the drive belt to form an abutting force so as to balance the pre-tightening force of the elastic member when the drive belt is in a normal working state, the pre-tightening force of the elastic member rotates the oscillating member to a direction of the locking member and cooperates with the locking member in a locking manner to realize braking when the length of the drive belt between the driven wheel and the driving wheel exceeds a preset value or is in a broken state.

2. A passenger boarding bridge comprising a tunnel having a cabin, a cab and a rotationally driving device for driving rotation of the cab, wherein the passenger boarding bridge further comprises the braking system according to claim 1 .

3. The braking system according to claim 1 , wherein a first friction structure is provided on the locking member, and a second friction structure that can cooperate with the first friction structure is provided on the oscillating member.

4. The braking system according to claim 1 , wherein the oscillating member is fixed on a shaft of the driven wheel.

5. The braking system according to claim 1 , wherein the oscillating member matches with the locking member in a locking manner to realize braking when the drive belt is loosened or the portion of the drive belt between the driven wheel and the driving wheel is broken.

6. The braking system according to claim 1 , wherein both of the driving wheel and the driven wheel are sprocket wheels, the drive belt is a drive chain, and the oscillating wheel is an oscillating sprocket wheel.

7. The braking system according to claim 6 , wherein the braking assembly further comprises:

a braking limit switch, which is triggered during the oscillating member is rotated to a direction of the locking member.

8. The braking system according to claim 1 , wherein a portion of the drive belt between the two driven wheels is in a “V” shape; the braking assembly comprises two sets that are a first braking assembly and a second braking assembly symmetrically arranged outside the “V”-shaped portion of the drive belt.

9. The braking system according to claim 8 , wherein the braking assembly further comprises:

a braking limit switch, which is triggered during the oscillating member is rotated to a direction of the locking member.

10. The braking system according to claim 1 , wherein the locking member is a chain or a rack, and a plurality of meshing teeth that can be engaged with the chain or the rack are provided on the oscillating member.

11. The braking system according to claim 10 , wherein the braking assembly further comprises:

a braking limit switch, which is triggered during the oscillating member is rotated to a direction of the locking member.

12. The braking system according to claim 1 , wherein a bump structure is provided on the locking member, and a groove structure that can match with the bump structure is provided on the oscillating member.

13. The braking system according to claim 12 , wherein the braking assembly further comprises:

a braking limit switch, which is triggered during the oscillating member is rotated to a direction of the locking member.

14. The braking system according to claim 1 , wherein the elastic member is a tension spring or a compression spring, and has one end connected to the oscillating member and the other end connected to the cab.

15. The braking system according to claim 14 , wherein the braking assembly further comprises:

a braking limit switch, which is triggered during the oscillating member is rotated to a direction of the locking member.

16. The braking system according to claim 1 , wherein the oscillating member is mounted on the cab through a pivot shaft, and the elastic member is a torsion spring mounted on the pivot shaft.

17. The braking system according to claim 16 , wherein the braking assembly further comprises:

a braking limit switch, which is triggered during the oscillating member is rotated to a direction of the locking member.

18. The braking system according to claim 1 , wherein the braking assembly further comprises:

a braking limit switch, which is triggered during the oscillating member is rotated to a direction of the locking member.

19. The braking system according to claim 18 , wherein the braking limit switch is installed on the cab, and has a movable portion that is located on a oscillating trace of the oscillating member.

20. The braking system according to claim 18 , wherein the braking limit switch sends a trigger signal to a control system of the passenger boarding bridge as being triggered, and the control system controls the driving motor to stop rotating according to the triggered signal.