Brake device for an elevator car, comprising an integrated load measuring device, use thereof in an elevator system, and method

Abstract

A braking apparatus, that brakes and measures load changes in an elevator car, includes a brake, a brake holding arrangement holding the brake on the car, a load measuring device measuring a force acting on a force transmission element and a load measuring device holding arrangement holding the load measuring device on the car. The brake can be displaced relative to the car in a force direction generated by the brake and the load measuring device is held on the car fixed relative to the car in the force direction. The force transmission element is operatively connected to the brake to measure a force acting between the brake and the load measuring device due to a relative displacement of the brake relative to the load measuring device. A connecting piece arrangement connects the load measuring device holding arrangement and the brake holding arrangement in an elastically deformable manner.

Claims

1. A braking apparatus for braking a displaceable elevator car of an elevator installation and for measuring load changes caused in the elevator car, the braking apparatus comprising: a brake adapted to brake the elevator car relative to a stationary component of the elevator installation; a brake holding arrangement adapted to hold the brake on the elevator car; a load measuring device having a force transmission element measuring a force acting on the force transmission element; a load measuring device holding arrangement adapted to hold the load measuring device on the elevator car; wherein the brake and the brake holding arrangement are held on the elevator car by the brake holding arrangement such that the brake can be displaced relative to the elevator car in a force direction generated by actuation of the brake; wherein the load measuring device and the load measuring device holding arrangement are held on the elevator car by the load measuring device holding arrangement such that the load measuring device is fixed relative to the elevator car in the force direction; wherein the force transmission element is operatively connected to the brake to measure a force acting between the brake and the load measuring device due to a displacement of the brake relative to the load measuring device; and wherein the load measuring device holding arrangement and the brake holding arrangement are connected to one another in an elastically deformable manner via a connecting piece arrangement.

2. The braking apparatus according to claim 1 wherein the brake can be displaced relative to the elevator car up to a predetermined position in the force direction.

3. The braking apparatus according to claim 1 wherein the brake holding arrangement has slots formed therein, a longitudinal direction of the slots extending parallel to the force direction, and fixing elements held stationary on the elevator car extend through the slots to hold the brake holding arrangement on the elevator car.

4. The braking apparatus according to claim 1 wherein the connecting piece arrangement deforms elastically when a force corresponding to a weight of the elevator car including a maximum permissible payload of the elevator car is transmitted between the brake holding arrangement and the load measuring device holding arrangement.

5. The braking apparatus according to claim 1 wherein the connecting piece arrangement deforms by less than 1 mm in the force direction when a force corresponding to a weight of the elevator car including a maximum permissible payload of the elevator car is transmitted between the brake holding arrangement and the load measuring device holding arrangement.

6. The braking apparatus according to claim 1 wherein the connecting piece arrangement extends transversely to the force direction at least in a sub-region of the connecting piece arrangement.

7. The braking apparatus according to claim 1 wherein the brake holding arrangement, the load measuring device holding arrangement and the connecting piece arrangement are formed in one piece by a common part.

8. The braking apparatus according to claim 7 wherein the one piece common part is formed of stamped sheet metal.

9. The braking apparatus according to claim 1 wherein the force transmission element is connected via a strain gauge to a counter-element of the load measuring device, the counter-element being fixed to the load measuring device holding arrangement.

10. The braking apparatus according to claim 1 wherein the load measuring device generates an electrical signal representing the force acting on the force transmission element.

11. The braking apparatus according to claim 1 wherein the brake is a holding brake for holding the elevator car stationary against its weight during a stop.

12. The braking apparatus according to claim 11 wherein the brake also is a safety brake for braking the elevator car in an emergency to stop a free fall of the elevator car.

13. An elevator installation comprising: an elevator car; a guide rail guiding the elevator car, the elevator car being displaceable along the guide rail; the braking apparatus according to claim 1; wherein the braking apparatus is held on the elevator car by the brake holding arrangement thereof and the load measuring device holding arrangement thereof; and wherein the brake interacts with the guide rail to brake the elevator car.

14. A method for measuring a load acting on an elevator car, the method comprising the steps of: providing the braking apparatus according to claim 1 on the elevator car; activating the brake of the braking apparatus while the elevator car is stationary; and measuring a load acting on the elevator car using the load measuring device of the braking apparatus.

15. A method for setting a force to be exerted by a drive device on an elevator car in response to a load change in the elevator car, the method comprising the steps of: performing the method according to claim 14 to measure a load change in the load acting on the elevator car; and setting the force exerted by the drive device on the elevator car to compensate for the measured load change.

16. The method according to claim 15 including further steps of, before the load change occurs, measuring the force acting between the brake and the load measuring device by the load measuring device as a reference force; and after activation of the brake and after the load change has occurred, setting the force exerted by the drive on the elevator car such the load measuring device measures a force corresponding to the reference force.

17. A braking apparatus for braking a displaceable elevator car of an elevator installation and for measuring load changes caused in the elevator car, the braking apparatus comprising: a brake adapted to brake the elevator car relative to a stationary component of the elevator installation; a brake holding arrangement adapted to hold the brake on the elevator car; a load measuring device having a force transmission element measuring a force acting on the force transmission element; a load measuring device holding arrangement adapted to hold the load measuring device on the elevator car; wherein the brake and the brake holding arrangement are held on the elevator car by the brake holding arrangement such that the brake can be displaced relative to the elevator car up to a predetermined position in a force direction generated by actuation of the brake; wherein the load measuring device and the load measuring device holding arrangement are held on the elevator car by the load measuring device holding arrangement such that the load measuring device is fixed relative to the elevator car in the force direction; wherein the force transmission element is operatively connected to the brake to measure a force acting between the brake and the load measuring device due to a displacement of the brake relative to the load measuring device, the load measuring device generating an electrical signal representing the force acting on the force transmission element; and wherein the load measuring device holding arrangement and the brake holding arrangement are connected to one another in an elastically deformable manner via a connecting piece arrangement, the connecting piece arrangement deforming elastically when a force corresponding to a weight of the elevator car including a maximum permissible payload of the elevator car is transmitted between the brake holding arrangement and the load measuring device holding arrangement, and the connecting piece arrangement extends transversely to the force direction at least in a sub-region of the connecting piece arrangement.

Description

DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 schematically shows an elevator installation according to an embodiment of the present invention.

(2) FIG. 2 schematically shows an elevator installation according to an embodiment of the present invention.

(3) FIG. 3 is a perspective view of a braking apparatus according to an embodiment of the present invention.

(4) The drawings are merely schematic and not to scale. Identical reference signs refer to identical or equivalent features in the various drawings.

DETAILED DESCRIPTION

(5) FIGS. 1 and 2 show differently designed elevator installations 1 having a braking apparatus 15 according to two embodiments of the present invention. In FIG. 3, a specific embodiment of the braking apparatus 15 is shown larger and with more detail.

(6) The elevator installation 1 shown in FIG. 1 comprises an elevator car 3 which can be held by cable-like or belt-like support means 5, for example, and displaced in an elevator shaft 11. The support means 5 can be displaced by a drive device 7 for this purpose. The drive device 7 is controlled by a controller 9. During its displacement, the elevator car 3 is guided on both sides on at least one guide rail 13 acting as a stationary component 14.

(7) In particular, in order to be able to keep the elevator car 3 stationary during a stop at a desired position, such as at a story, the elevator car 3, after it has been moved to the desired position by means of the drive device 7, can be temporarily fixed with the aid of brakes 17 provided on its braking apparatuses 15 to the stationary guide rails 13. Each of the brakes 17 is fastened to a frame of the elevator car 3, for example, with the aid of brake holding arrangements 19.

(8) At least one of the braking apparatuses 15 also has a load measuring device 21. The load measuring device 21 has a force transmission element 25 and a counter-element 29. Between the force transmission element 25 and the counter-element 29, the load measuring device 21 can have a sensor, for example in the form of a strain gauge 27, with the aid of which a force acting on the load measuring device 21 between the force transmission element 25 thereof and the counter-element 29 thereof can be measured. The load measuring device 21 can, for example, have evaluation electronics in its counter-element 29, by means of which electronics the measurement parameters prevailing at the sensor can be converted into electrical signals. The load measuring device 21 is also fastened to the elevator car 3 via a load measuring device holding arrangement 23.

(9) FIG. 2 shows a further embodiment of an elevator installation 1 according to the invention. In this case, the braking apparatus 15 is shown only schematically and can be configured to be similar in detail to the embodiment shown in FIG. 1. The elevator installation 1 has an elevator car 3 and two counterweights 8. The elevator installation 1 comprises two drive devices 7, which are arranged in a shaft pit 10 of an elevator shaft 11. The traction and suspension are separate in such an embodiment, i.e. two traction support means 4 (below the car) and two suspension support means 6 (above the car) are used.

(10) A braking apparatus 15 as described above and below proves to be particularly advantageous when used in such an elevator installation 1, since braking on the drive devices 7, i.e. via traction support means 4, which are not stressed by the weight of the elevator car 3 can be avoided.

(11) It also proves to be advantageous in such an elevator installation 1 to integrate the load measurement in the braking apparatus 15 provided on the elevator car 3 and not to carry it out in the support means fastenings, as is usually the case. A load measurement via the suspension support means 6 is difficult in such an elevator installation 1 since the forces in the suspension support means 6 are also influenced by an unknown variable due to the prestressing of the traction support means 4. In order to carry out a load measurement at the traction support means 4, a sensor would have to be attached to the traction support means 4 and a sensor would have to be attached to the suspension support means 6. In order to be able to achieve precise measurement results even when the load is unevenly distributed in the elevator car 3, the measurement must be carried out on both sides of the elevator car 3. A total of four sensors would therefore have to be installed.

(12) If the load measurement is at the braking apparatus 15, a reliable measurement can be achieved with only two sensors.

(13) In a further, slightly modified embodiment, the two drive devices are arranged at the top of the shaft head 12 of the elevator shaft 11 (not shown).

(14) In one embodiment, the load measurement may only be at one braking apparatus 15. As can be seen in particular in FIG. 3, the load measuring device holding arrangement 23 and the brake holding arrangement 19 are connected to one another via a connecting piece arrangement 31 so as to be mechanically loadable.

(15) A plurality of slots 35 is formed in the brake holding arrangement 19. A longitudinal direction of the slots 35 is substantially parallel to a force direction 39 in which a force generated by the brake 17 is directed. The force direction 39 substantially corresponds to the direction of movement of the elevator car 3 and is therefore substantially vertical. The length of the slots 35 can, for example, be about 0.5 mm greater than their width. The plurality of slots 35 are arranged linearly one above the other in the force direction 39. A fixing element 36 (FIG. 1), for example in the form of a bolt or a screw, can extend through each of the slots 35 and can be fixed to the elevator car 3 or to the frame thereof. The brake holding arrangement 19 can thus be held on the elevator car 3 via the fixing elements 36, but can be vertically moved slightly relative to the elevator car 3 by displacing the fixing elements 36 within the slots 35.

(16) The load measuring device holding arrangement 23 has a plurality of round holes 33. Fixing elements (not shown) can in turn extend through the round holes 33, via which elements the load measuring device holding arrangement 23 can be fastened to the elevator car 3 or to the frame thereof substantially without play.

(17) Accordingly, the brake 17 held by the brake holding arrangement 19 can be displaced slightly in the force direction 39 relative to the load measuring device holding arrangement 23 or relative to the elevator car 3 when a force in the force direction 39 is generated by activating the brake 17.

(18) Such a relative displacement causes, inter alia, a deformation of the connecting piece arrangement 31. The connecting piece arrangement 31 is arranged, dimensioned, and configured in such a way that this deformation is usually elastic, at least as long as the brake 17 only generates the forces required to hold the elevator car 3 and the payload thereof, for example when stopping at a story.

(19) However, the relative displacements between the brake 17 and the car 3 caused when the brake 17 is activated can also be used to make it possible to use the load measuring device 21 to measure loads or load changes currently acting on the elevator car 3.

(20) For this purpose, in the example shown, the counter-element 29 of the load measuring device 21 is fixedly connected, for example screwed, to the load measuring device holding arrangement 23. The force transmission element 25 is coupled, for example, to a part of the brake holding arrangement 19 and is thus operatively connected to the brake 17. Electronics (not shown) provided in counter-element 29, for example, can be used e.g. to measure mechanical stresses that occur in the strain gauge 27 arranged between the force transmission element 25 and the counter-element 29 due to the forces generated by the relative displacement. The electronics can then produce an electrical signal which can act as a measure of the force to which the load measuring device 21 is subjected.

(21) It is therefore possible not only to use the brake 17 of the braking apparatus 15 to brake the elevator car 3, but also to use the load measuring device 21 of the braking apparatus to measure a load acting on the elevator car 3.

(22) During operation of the elevator installation 1, the elevator car 3 can be transported to a story by means of the drive device 7, for example. In order to prevent the elevator car 3 from subsequently moving up or down when passengers get on and off due to the resulting load changes, the brake 17 of the braking apparatus 15 can be activated, for example via a control line 37, before the car doors are opened.

(23) A force currently acting between the brake 17 and the elevator car 3 can be measured using the load measuring device 21 in advance or at least before a load change can occur in the elevator car 3, i.e. before the car door is opened, for example. This force can usually be zero, for example, particularly if the elevator car 3 was braked to a standstill exclusively by controlling the drive device 7 and the brake 17 was only activated afterwards. However, if the brake 17 was also used to decelerate the movement of the elevator car 3, this force can also have a value other than zero. This previously measured force can be stored as a reference value.

(24) As soon as load changes occur when passengers subsequently get in and out of the car, they can be measured using the load measuring device 21. The information about the measured load changes can be used to vary the forces exerted on the elevator car 7 via the support means 5 by controlling the drive device 7 in a targeted manner in such a way that the load changes which have occurred in the meantime are compensated for.

(25) Alternatively, the drive device 7 can change the forces acting on the elevator car 3 via the support means 5 until the force currently measured by the load measuring device 21 matches the previously determined reference value again.

(26) It can be ensured in both cases that changed load conditions within the elevator car 3 are compensated for by suitably tensioning or relaxing the support means 5 using the drive device 7 in such a way that the entire elevator car 3, including the payload thereof, which has changed in the meantime, is held by the support means 5 again. In this state, the brake 17 can be released without the elevator car 3 then moving abruptly. This also applies to the embodiment shown in FIG. 2.

(27) Finally, it should be noted that terms such as “comprising,” “having,” etc. do not preclude other elements or steps, and terms such as “a” or “an” do not preclude a plurality. Furthermore, it should be noted that features or steps that have been described with reference to one of the above embodiments may also be used in combination with other features or steps of other embodiments described above.

(28) 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.