BRAKING DEVICE FOR AN ELEVATOR SYSTEM

Abstract

A braking device may be utilized by an elevator system that has a cabin that is movable within an elevator shaft. The braking device may comprise an actuator and a brake. The actuator may be configured to provide an actuating force for the brake as needed. The braking device may include a force measuring assembly for generating a load state value of the cabin. The force measuring assembly may be mechanically coupled to the actuator such that the actuating force is dependent on the load state value. The actuator may be configured such that the greater the load state value the greater the actuating force.

Claims

1.-10. (canceled)

11. A braking device for an elevator system with a cabin that is movable inside an elevator shaft, the braking device comprising: a brake; an actuator configured to provide an actuating force for the brake; and a force measuring assembly for generating a load state value of the cabin, wherein the force measuring assembly is mechanically coupled to the actuator such that the actuating force is dependent on a load state value.

12. The braking device of claim 11 wherein the actuator is configured such that the greater the load state value the greater the actuating force.

13. The braking device of claim 11 wherein the force measuring assembly comprises a load cell that is adapted to detect a weight force of the cabin, wherein the force measuring assembly is configured to generate the load state value from the weight force.

14. The braking device of claim 11 wherein the force measuring assembly comprises at least three load cells that are adapted to detect a weight force of the cabin, wherein the force measuring assembly is configured to generate the load state value from the weight force.

15. The braking device of claim 11 wherein the force measuring assembly comprises a low pass filter adapted to filter dynamic influences out of a primary value of the load state value.

16. The braking device of claim 11 comprising a stop for limiting an influence of the load state value on the actuating force.

17. The braking device of claim 11 wherein the actuator comprises a force capacity for providing the actuating force, the actuator being configured such that a preload of the force capacity is set as a function of the load state value.

18. The braking device of claim 17 wherein the actuator is configured such that in a standby mode the force capacity is held in a standby position against the actuating force, wherein in the standby position the actuating force is not applied to the brake, wherein in an operating mode the force capacity is not held in the standby position and the actuating force is applied to the brake.

19. The braking device of claim 17 wherein the force measuring assembly is configured to pass the load state value on to the actuator by way of a pressurized fluid.

20. The braking device of claim 19 wherein the actuator is configured for the pressurized fluid to preload the force capacity or at least to increase a preload of the force capacity.

21. A method for setting an actuating force of the braking device of claim 11, the method comprising: generating the load state value of the cabin by way of the force measuring assembly; communicating the load state value from the force measuring assembly to the actuator via a mechanical coupling; and setting the actuating force depending on the communicated load state value.

22. An elevator system comprising: a cabin that is movable inside an elevator shaft; and a braking device comprising a brake, an actuator configured to provide an actuating force for the brake, and a force measuring assembly for generating a load state value of the cabin, wherein the force measuring assembly is mechanically coupled to the actuator such that the actuating force is dependent on a load state value.

23. The elevator system of claim 22 wherein the actuator is configured such that the greater the load state value the greater the actuating force.

24. The elevator system of claim 22 wherein the force measuring assembly comprises a load cell that is adapted to detect a weight force of the cabin, wherein the force measuring assembly is configured to generate the load state value from the weight force.

25. The elevator system of claim 22 wherein the force measuring assembly comprises at least three load cells that are adapted to detect a weight force of the cabin, wherein the force measuring assembly is configured to generate the load state value from the weight force.

26. The elevator system of claim 22 wherein the force measuring assembly comprises a low pass filter adapted to filter dynamic influences out of a primary value of the load state value.

27. The elevator system of claim 22 comprising a stop for limiting an influence of the load state value on the actuating force.

28. The elevator system of claim 22 wherein the actuator comprises a force capacity for providing the actuating force, the actuator being configured such that a preload of the force capacity is set as a function of the load state value.

29. The elevator system of claim 28 wherein the actuator is configured such that in a standby mode the force capacity is held in a standby position against the actuating force, wherein in the standby position the actuating force is not applied to the brake, wherein in an operating mode the force capacity is not held in the standby position and the actuating force is applied to the brake.

30. The elevator system of claim 28 wherein the force measuring assembly is configured to pass the load state value on to the actuator by way of a pressurized fluid.

Description

[0018] The invention will now be explained in detail with reference to the figures, in which in each case

[0019] FIG. 1 schematically shows an inventive elevator system, which comprises a braking device according to the invention;

[0020] FIG. 2 schematically shows the components of the braking device of the elevator system of FIG. 1;

[0021] FIG. 3 a) schematically shows a throttle unit of the braking device of FIG. 2, [0022] b) shows the step response diagram associated with the throttle unit.

[0023] FIG. 4 schematically shows the progression of selected pressure and force values during operation.

[0024] FIG. 1 shows an elevator system 1 according to the invention, which comprises a cabin 2 which is received within an elevator shaft 3. The cabin 2 is held vertically movably in guide rails 4 by means of guide rollers not shown. The elevator system 1 further comprises a braking device 5 with at least one brake 6. In case of a defect one or more such brakes 6 can be activated. The braking device 5 comprises an actuator 7 which provides a braking force when needed. The braking force is transferred to the brakes 6 via a connector 8.

[0025] FIG. 2 shows the braking device 5 in more detail. The braking device accordingly comprises three essential components, i.e. the brake 6, the actuator 7 and a force measuring assembly 18.

[0026] The brake 6 when actuated starts to interact with the guide rail 4 in order to thereby at least reduce the speed of the cabin 2, in particular to bring the cabin to a standstill. The actuator 7 actuates the brake 6. In doing so the actuator 7 generates an actuating force B when needed, as a result of which the brake 6 starts to interact with the rail 4.

[0027] In the present example the actuator comprises an actuating cylinder 10, in which a first working piston 13 is arranged. On the one hand this first working piston 13 is impacted by a spring 9, which is dimensioned so as to apply the actuating force B. On the other hand the first working piston 13 is held back by a pneumatic medium 27 (e.g. air) present in a first working chamber 11 at a pneumatic pressure p.sub.11 in a standby state. The pneumatic pressure p.sub.11 counteracts the spring 9, so that the actuator cannot apply the actuating force B to the brake 6. When needed a vent valve 16 is opened and the pneumatic pressure p.sub.11 can escape from the first working chamber 11. The actuating force B which can be generated by the force capacity 9, can now be transferred via the connector 8 to the brake 6. A clearance 26 between the two working pistons 13, 14 can be impacted by environmental pressure.

[0028] The force capacity 9 is preloaded by a second working piston 14, which is also arranged in the actuating cylinder. Counteracting the spring 9 is a second working chamber 12 arranged on the other side of the second working piston 14, and this working chamber 12 contains a hydraulic oil 24. The hydraulic oil 24 is pressurized by load cells 19, which are connected via a hydraulic connection 25 to the second working chamber 12. The load cells are arranged below the cabin 2 and are impacted according to the load of the cabin 2 including the cabin content. Depending on the weight of the cabin a primary pressure p.sub.19 is generated by the load cells 19, which equally represents an unfiltered hydraulic pressure value. Preferably at least three load cells 19 are provided for support the cabin floor without tilting.

[0029] A low pass filter 20, here in the form of a throttle, is arranged in the hydraulic connection 25 between the load cells 19 and the second working chamber 12. An example of a throttle is shown in detail in FIG. 3a, and the associated step response diagram is shown in FIG. 3b. The low pass filter 20 comprises an inlet 21, which is connected via a first line 251 to the load cell 19. At the inlet 21 the hydraulic primary pressure p.sub.19 is present, which is provided by the load cells 19. The inlet 21 is connected to an outlet 23 via a throttle point 22 with reduced line cross-section, which in turn is connected via a second line 252 to the second working chamber 12. The secondary pressure p.sub.20 present at the outlet 23 which simultaneously represents a filtered hydraulic pressure value, is also present in the second working chamber 12 and has a major impact on the preload force for the spring 9. The second line 252 represents the coupling between the force measuring assembly 18 and the actuator 7.

[0030] The importance of the low pass filter 20 is explained by way of the diagram in FIG. 4. The diagram shows the progression of the primary pressure p.sub.19 and the secondary pressure p.sub.20. The progression of the secondary pressure p.sub.20 is shown by a continuous line. At the point where the progression of the primary pressure p.sub.19 is different from the progression of the secondary pressure p.sub.20, the diagram shows the progression of the primary pressure p.sub.19 in the form of a dotted line. The progression of the primary pressure p.sub.19 is essentially identical to a cabin load F, which impacts the load cells 19 from above. In addition the pneumatic pressure p.sub.11 in the first working chamber 11 is shown at the top.

[0031] At the point in time t.sub.0 the cabin 2 is stationary on one floor. The doors open. At the point in time t.sub.1 a first person boards, at the point in time t.sub.2 a second person boards. Boarding of the persons is depicted by a step each in the progression of the primary pressure p.sub.19. Due to the inertia of the filter 20 the progression of the secondary pressure p.sub.20 is delayed in terms of time. The doors close and the cabin 2 moves downwards. Due to the downward acceleration the load on the load cells 19 is reduced, the primary pressure p.sub.19 drops temporarily. Again the progression of the secondary pressure p.sub.20 is delayed in terms of time. As from point in time t4 the cabin 2 descends at a constant speed.

[0032] At the point in time t.sub.5 emergency braking is initiated by opening of the valve 16, with no pneumatic pressure p.sub.11 present. Immediately afterwards the brake 6 is activated and braking of the cabin 2 is complete as soon as point in time t.sub.6 is reached. Due to massive acceleration during the braking operation primary pressure p.sub.19 temporarily rises. Due to the progression of the primary pressure p.sub.19 it can be seen that the dynamic primary pressure p.sub.19 is not sufficiently representative of the load state of the cabin.

[0033] Although the secondary pressure p.sub.20 follows the progression of the primary pressure p.sub.19, the progression is substantially attenuated. In particular during the braking operation in the period between t.sub.5 and t.sub.6 the secondary pressure p.sub.20 represents a value, which maps the actual load state substantially better than the primary pressure p.sub.19. Due to a suitable selection of the filter parameters the progression of the secondary pressure p.sub.20 can be optimized during the braking operation.

LIST OF REFERENCE SYMBOLS

[0034] 1 elevator system [0035] 2 cabin [0036] 3 elevator shaft [0037] 4 guide rails [0038] 5 braking device [0039] 6 brake [0040] 7 actuator [0041] 8 connector [0042] 9 preload spring [0043] 10 actuating cylinder [0044] 11 first working chamber (pneumatic chamber) [0045] 12 second working chamber (hydraulic chamber) [0046] 13 first working piston [0047] 14 second working piston [0048] 15 vent line [0049] 16 vent valve [0050] 17 stop [0051] 18 force measuring assembly [0052] 19 load cell [0053] 20 throttle unit [0054] 21 inlet [0055] 22 throttle piece [0056] 23 outlet [0057] 24 hydraulic oil [0058] 25 hydraulic line [0059] 26 clearance [0060] 27 pneumatic medium [0061] P.sub.19 unfiltered hydraulic pressure value [0062] p.sub.20 filtered hydraulic pressure value [0063] P.sub.11 pneumatic pressure valve [0064] F cabin load [0065] B actuating force