ELEVATOR SYSTEM, BRAKE SYSTEM FOR AN ELEVATOR SYSTEM AND METHOD FOR CONTROLLING A BRAKE SYSTEM OF AN ELEVATOR SYSTEM

Abstract

An elevator system includes an elevator car, at least one elevator drive arranged in an elevator shaft and a support strap, wherein the elevator car is arranged in the elevator shaft for movement via the support strap by the elevator drive. A brake system includes a car braking unit associated with the elevator car and a drive braking unit associated with the elevator drive. The car braking unit and the drive braking unit can together be controlled from a common brake control device. The brake system can be used for new elevator system installations and for retrofitting existing elevator systems.

Claims

1-15. (canceled)

16. An elevator system including an elevator car, an elevator drive and a support means, wherein the elevator car is moved in an elevator shaft by the elevator drive via the support means, comprising: a car braking unit for braking the elevator car; a drive braking unit for braking the elevator drive; and a brake control unit for controlling the car braking unit and the drive braking unit, wherein the brake control device controls the car braking unit and the drive braking unit for joint actuation so that the car braking unit and the drive braking unit are actuated jointly and together as a redundantly operating brake system.

17. The elevator system according to claim 16 wherein the car braking unit is fixed to the elevator car and interacts with at least one guide rail of the elevator shaft.

18. The elevator system according to claim 17 wherein the car braking unit comprises two brakes, which brakes are arranged on respectively opposite sides of the elevator car and which brakes each interact with a guide rail of the elevator shaft.

19. The elevator system according to claim 16 wherein the brake control unit actuates the car braking unit in at least two stages of braking.

20. The elevator system according to claim 16 wherein the elevator system is a traction elevator system without a counterweight or a drum elevator system.

21. The elevator system according to claim 20 wherein the drive braking unit and the car braking unit can safely decelerate the elevator car loaded with a permissible payload independently of each other, and each generate a braking force which is a sum of a weight of the elevator car empty, a weight of the permissible payload and a weight of additional masses including the support means.

22. The elevator system according to claim 16 wherein the elevator system is a traction elevator system with a counterweight supported by the support means.

23. The elevator system according to claim 22 wherein the drive braking unit can safely decelerate the elevator car loaded with a permissible payload and generate a drive braking force defined by a counterbalancing by the counterweight in relation to a weight of the permissible payload, and the car braking unit can safely decelerate the elevator car loaded with the permissible payload independently of the counterweight and generate a car braking force defined by a sum of a weight of the empty elevator car, the weight of the permissible payload and a weight of additional masses including the support means.

24. The elevator system according to claim 22 wherein the drive braking unit can safely decelerate the elevator car loaded with a permissible payload and generate a drive braking force defined by a counterbalancing by the counterweight in relation to a weight of the permissible payload, and the car braking unit, in a first braking stage, can safely decelerate the elevator car loaded with the permissible payload and accordingly generate a first car braking force defined by the counterbalancing in relation to the weight of the permissible payload, and the car braking unit can safely decelerate the elevator car loaded with the permissible payload independently of the counterweight and accordingly generate a second car braking force that is a sum of the weight of the empty elevator car, the weight of the permissible payload and a weight of additional masses including the support means.

25. A brake system for an elevator system, the elevator system including an elevator car movable by an elevator drive, comprising: a car braking unit for braking the elevator car; a drive braking unit for braking the elevator drive; and a brake control unit connected via at least one communication interface to the car braking unit and to the drive braking unit, the brake control unit jointly controlling the car braking unit and the drive braking unit for joint actuation to operate as a redundantly operating brake system.

26. The brake system according to claim 25 wherein the car braking unit and the drive braking unit are of different construction.

27. A method for controlling a brake system of an elevator system, the elevator system including a car braking unit for braking an elevator car and a drive braking unit for braking an elevator drive, comprising the steps of: providing a brake control device in communication with the car braking unit and the drive braking unit; and operating the brake control device to jointly control the car braking unit and the drive braking unit so that the car braking unit and the drive braking unit are actuated jointly and together as a redundantly operating brake system.

28. The method according to claim 27 including operating the brake control unit to control the car braking unit in a first step to generate a first braking force equal to a braking force generated by the drive braking unit.

29. The method according to claim 28 including operating the brake control unit to control the car braking unit in a second step to generate a second braking force greater than the first braking force.

30. The method according to claim 27 wherein the brake control unit, in response to an emergency stop being triggered, controls the car braking unit and the drive braking unit to generate together a full braking force.

31. The method according to claim 30 wherein the brake control unit, in response to detection of a free-fall of the elevator car, controls at least the car braking unit to generate the full braking force.

Description

DESCRIPTION OF THE DRAWINGS

[0039] The invention will now be explained more clearly by reference to the drawings. Shown are:

[0040] FIG. 1 is a schematic side view of an elevator shaft of a first embodiment of the invention,

[0041] FIG. 2 is a schematic sectional view through the elevator shaft of FIG. 1,

[0042] FIG. 3 is a schematic side view of an elevator shaft of a second embodiment of the invention, and

[0043] FIG. 4 is a schematic side view of an elevator shaft of a further embodiment of the invention.

DETAILED DESCRIPTION

[0044] In FIG. 1 a schematic view of an elevator shaft 3 of an elevator system 1 is shown. The elevator system 1 comprises an elevator car 2, which is located on a landing E.sub.1. Further landings of the elevator shaft 3 are represented as E.sub.2 to E.sub.n. The elevator system 1 of FIG. 1 is designed as a traction elevator system 11 with a counterweight 12, wherein the support means 5 are designed as support straps and are routed under the elevator car 2 and around a traction sheave 17.

[0045] In the elevator shaft 3 guide rails 9 for the elevator car 2 and the counterweight 12 are also located, which are used to guide and stabilize the elevator car 2 or counterweight 12 respectively. The elevator car 2 is equipped with a car braking unit 6, which is located under the elevator car 2.

[0046] FIG. 2 shows a schematic view of the elevator system 1 from above. The guide rails 9, which in each case guide the elevator car 2 and the counterweight 12 in pairs, are clearly visible.

[0047] The car braking unit 6 of the elevator car 2 consists of two brakes, which are arranged underneath the elevator car 2 and to the side, near to deflection pulleys 16 of the support means 5. Suitable devices for the car braking units 6 are primarily electrically actuated brakes. These can be, for example, magnetically releasable clasp brakes, hydraulic-caliper brakes, or else multi-stage controllable brakes, as is known, for example, from document EP 1930282.

[0048] Both brakes of the car braking unit 6 interact with one guide rail 9 each to brake the elevator car 2, and also serve as a trapping device. No separate trapping device is provided.

[0049] In the region of the drive the elevator system 1 is also equipped with a drive braking unit 7, which directly interacts with the elevator drive 4 and the traction sheave 17. The elevator drive 4 can be a geared drive or also a gearless machine. The drive braking unit 7 can be designed as a disc brake, preferably a spring-force brake, a drum brake or other type of design.

[0050] Both the car braking unit 6 and the drive braking unit 7 are connected to a common brake control device 8 and to each other via a connection cable 18, shown schematically with a dash-dotted line, and respective communication interfaces 14 and 15.

[0051] In this exemplary embodiment the brake control device 8 is arranged in the elevator shaft 3 and integrated in a control device, which also performs the control of the entire elevator system 1. Naturally, the brake control device 8, in particular if it is a brake system which is intended for retrofitting in already existing elevator systems, can be designed as a separate unit.

[0052] The brake control device 8 can, depending on the specific application, also be arranged on the elevator car 2, however.

[0053] In FIG. 3 a second preferred embodiment of an elevator system 1 according to the invention is shown. Identical reference numerals indicate identical or equivalent parts, which have already been described above in relation to FIGS. 1 and 2.

[0054] The elevator system 1 is designed as a traction elevator system 11 with a counterweight 12. The counterweight 12 in this exemplary embodiment—viewed from the landing E.sub.1 to E.sub.n—is arranged behind the car 2. The car 2 and the counterweight 12 are in turn supported by a support means 5, which is guided and driven via a traction sheave arrangement 17 of the elevator drive 4.

[0055] The brake control device 8 is arranged on the elevator car 2. The car or drive braking unit 6, 7 is designed with an integrated communication interface 14, 15 respectively and connected via a connecting cable 18 to the brake control device 8.

[0056] In FIG. 4 a further alternative embodiment of an elevator system 1 is shown. Identical reference numerals again indicate identical or equivalent parts, which have already been described above in relation to FIGS. 1 and 3.

[0057] The elevator system 1 is designed a counterweight-free traction elevator 11a. The car 2 is again supported by a support means 5. This support means 5 is guided and driven via a traction sheave arrangement 17a of the elevator drive 4. The support means 5 is routed on the opposite side—on the side occupied previously by the counterweight—loosely in the elevator shaft 3 using a substantially free strand 5.1. If necessary, a small tension weight is attached, which is only used for holding the strand 5.1 tight, however, and for guiding the same if necessary. A transmission of traction from the traction sheave arrangement 17a to the support means 5 is ensured by means of a pressure roller 19, which presses the support means 5 onto the traction sheave arrangement 17a. In addition, a deflection pulley 20 is provided, which steers the support means 5 back into the elevator shaft 3.

[0058] Alternatively, the traction sheave arrangement 17a in accordance with the present exemplary embodiment can be replaced by a drum drive. In this case the support means is coiled up, in a drum, for example. The strand 5.1 freely suspended in the elevator shaft is then omitted.

[0059] The brake control device 8 in this exemplary embodiment is preferably again arranged in the elevator shaft 3. In the case of a counterweight-free elevator system 11a there is a need to keep the elevator car 2 as light as possible, since its empty weight is clearly not compensated. The arrangement of the brake control device 8 in the elevator shaft 3 takes this appropriately into account. The car braking unit 6 with the corresponding communication interface 14 is located on the elevator car 2. In a simple design, the communication interface 14 includes on the one hand the power supply for an electromagnet of the car braking unit 6 in order to hold this in its open condition, and also includes a position signal from the car braking unit 6, which indicates whether the car braking unit 6 is in its open or closed position. In a more complex design, other parameters such as wear condition, temperature, other position settings, etc. can of course also be communicated. This type of arrangement and design of the communication interface 14 can also be used in the other exemplary embodiments. The drive unit 4 accordingly includes the drive braking unit 7 with the associated communication interface 15. The communication interface 15 of the drive braking unit 7 is designed in exactly the same way as the previously described communication interface 14 of the car braking unit 6.

[0060] Hereafter, an elevator system 1 according to the invention is compared with an elevator system according to the prior art. In this comparison, constant reference will be made to an elevator system 1 with a mass of the elevator car 2=K; a mass of the support means 5 (plus any cable masses)=S and a rated load=F.

[0061] In the case of an elevator 11a without a counterweight, such as a drum elevator system or a traction elevator as previously described, two drive braking units are provided in accordance with the prior art, each of which must generate a brake force F.sub.AB>(K+F+S)*g. This means that the elevator car can be safely stopped or braked with the required redundancy. In addition a trapping device is present, which also generates a brake force F.sub.FV>(K+F+S)*g. By means of the trapping device the elevator car can be stopped independently of the drive in the event of failure of the support means. Of course, in calculating the brake force, excess factors are applied to the design of the brake system in order to guarantee safe functioning over a longer period of time.

[0062] It is apparent therefore that in this case, more than three times the braking force is provided. This means that, for example if all three brake systems respond at the same time, a very large deceleration of the elevator car can occur.

[0063] In accordance with one aspect of the solution it is then proposed to design the drive braking unit 7 for generating a single brake force F.sub.AB>(K+F+S)*g, while at the same time the car braking unit 6 can produce a braking force F.sub.KB of the same order of magnitude>(K+F+S)*g. The total braking force F.sub.AB+F.sub.KB that can be generated is therefore lower than in an elevator system according to the prior art, since in total only about twice the braking force is available. The overall safety of the elevator system is maintained, because the car braking unit 6 is activated together or jointly with the drive braking unit 7.

[0064] The operation ‘greater than’ (>) is to be understood to mean that a corresponding excess factor is applied. Based on experience, this factor is approximately 20%-50% (factor of 1.2-1.5), wherein for precisely known load conditions the lower excess factor is aimed for.

[0065] In the case of a traction elevator system 11 with a counterweight 12 having a mass=KA*F+K+S (the factor KA corresponds to the percentage of the rated load which is compensated or counterbalanced by the counterweight), the two drive braking units must each be able to generate a braking force F.sub.AB>((1−KA)*F)*g. In the case of 50% counterbalancing it must therefore be the case that F.sub.AB>((1−0.5)*F)*g and with a 30% counterbalance, F.sub.AB>((1−0.3)*F)*g. In addition, the trapping device is designed to provide a braking force F.sub.FV>(K+F+S)*g. In addition, brake force excess factors are applied in the calculation of the brake system in order to guarantee safe functioning over a longer period of time. It turns out, therefore, that an excessive braking force is also available in this case.

[0066] The above formulas for the design of the braking force F.sub.AB apply for a counterbalance KA in the range of 0 to 50%. A counterbalance above this range is irrelevant in practice, or not applied.

[0067] In accordance with one aspect of the solution it is then proposed to design the drive braking unit 7 for generating a single brake force F.sub.AB>((1−KA)*F)*g, while the car braking unit 6 can continue to generate a braking force F.sub.KB>(K+F+S)*g. The total generatable braking force F.sub.AB+F.sub.KB is therefore lower than in an elevator system according to the prior art.

[0068] It is therefore possible to save costs, since the redundancy within the drive braking unit itself is not necessary. In addition, weight savings are therefore possible, which enable more cost-effective and energy-efficient drives to be installed.

[0069] Instead of the elevator system 1 of FIGS. 1 to 4 being a new installation, a brake system according to the invention comprising a car braking unit 6 with associated communication interface 14, a drive braking unit 7 with associated communication interface 15 and a brake control device 8 can be retrofitted in already existing elevator systems 1.

[0070] In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.