Braking device for an elevator car with integrated load measuring device and its use in an elevator system and method

Description

[0001] The present invention relates to a braking device for an elevator system, which can be used both to brake a displaceable elevator car and to measure load changes induced in the elevator car. The invention further relates to an elevator system equipped with such a braking device. Furthermore, the invention relates to a method for measuring a load acting on an elevator car and a method for adjusting a force to be exerted by a drive device on an elevator car in response to a load change in the elevator car using the braking device described herein.

[0002] In an elevator system, an elevator car is typically moved within a vertical elevator shaft between different levels or floors in a building. The elevator car's movement is achieved using a drive system that drives the supporting elements that hold the elevator car, such as ropes or belts. The elevator car is usually guided along guide rails during its movement. To bring the elevator car to a stop at a desired floor, its movement is generally slowed by appropriately controlling the drive system.

[0003] When people enter or exit an elevator car that is stopped at a floor, a resulting change in load can lead to an elastic change in the length of the support members holding the elevator car. Accordingly, the position of the elevator car relative to the floor can change slightly while the car is stopped at that floor. To prevent a step from forming between the floor of the elevator car and the floor at that floor, a change in the position of the elevator car was traditionally compensated for using a so-called re-leveling system. This involves the drive device deliberately shifting the support members holding the elevator car in such a way as to counteract the change in position of the elevator car. However, implementing such leveling requires complex measures.

[0004] Alternatively, it has been suggested to install a brake directly on the elevator car, which can be used to hold the car in position during a stop at a floor. However, this could pose the problem that a change in the car's load during the stop could result in a sudden change in the car's position when the brake is subsequently released due to the changed car load.

[0005] Approaches have been described for measuring the load acting on an elevator car. For example, EP 1 278 694 B1 describes a load-carrying device for cable elevators with an integrated load-measuring device. EP 0 151 949 A2 describes an alternative load-measuring device for an elevator car. US 6,483,047 B1, JPH07157212A, and JPH03216477A describe alternative brake load-measuring systems in which load cells interact with a brake.

[0006] There may be, among other things, a need for a braking device that can advantageously brake an elevator car of an elevator system and that is also designed to measure a load change caused in the elevator car. Furthermore, there may be a need for an elevator system equipped with such a braking device. Furthermore, there may be a need for an advantageous method for measuring a load acting on an elevator car. Finally, there may be a need for an advantageous method for adjusting a force exerted by a drive device on an elevator car in response to a load change in the elevator car.

[0007] Such a need may be met by the subject matter of each of the independent claims. Advantageous embodiments are defined in the dependent claims and the following description.

[0008] According to a first aspect of the invention, a braking device for braking a displaceable elevator car of an elevator system and for measuring load changes caused in the elevator car is proposed. The braking device comprises a brake for braking the elevator car relative to a stationary component of the elevator system, a brake holding arrangement for holding the brake to the elevator car, a load measuring device with a force transmission element for measuring a force acting on the force transmission element, and a load measuring device holding arrangement for holding the load measuring device to the elevator car. The brake and the brake holding arrangement are configured such that the brake can be held to the elevator car by means of the brake holding arrangement in such a way that the brake can be displaced relative to the elevator car in a force direction caused by the brake.The load measuring device and the load measuring device holding arrangement are configured such that the load measuring device can be held on the elevator car by means of the load measuring device holding arrangement such that the load measuring device is fixed relative to the elevator car in the direction of the force exerted by the brake. The force transmission element of the load measuring device is operatively connected to the brake in order to be able 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. The load measuring device holding arrangement and the brake holding arrangement are elastically deformably connected to one another via a web arrangement.

[0009] According to a second aspect of the invention, an elevator installation is described, which comprises an elevator car, a guide rail, and a braking device according to an embodiment of the first aspect. The elevator car is displaceable along the guide rail. The braking device is held on the elevator car by means of its brake holding arrangement and its load measuring device holding arrangement. The brake of the braking device is configured to interact with the guide rail to brake the elevator car.

[0010] According to a third aspect of the invention, a method for measuring a load acting on an elevator car is described. The method comprises at least the following steps: (i) activating the brake of a braking device mounted on the elevator car according to an embodiment of the first aspect of the invention while the elevator car is stationary; and (ii) measuring the load acting on the elevator car using the load measuring device of the braking device.

[0011] According to a fourth aspect of the invention, a method is described for adjusting 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 comprises at least the following steps: (i) measuring the load change using a method according to an embodiment of the third aspect of the invention; and (ii) adjusting the force exerted by the drive device on the elevator car such that the measured load change is compensated.

[0012] Possible features and advantages of embodiments of the invention may be considered, among other things and without limiting the invention, to be based on ideas and findings described below.

[0013] In brief, the basic concept of the braking device proposed here can be seen as enabling two functionalities with a single device: braking the elevator car and measuring a load change caused in the elevator car. For this purpose, the braking device is essentially constructed in two parts.

[0014] A first part comprises the brake and the brake-holding assembly. The brake is designed to generate forces between the elevator car and a stationary component of the elevator system, such as a guide rail. These forces counteract any movement of the elevator car or its weight to decelerate the movement of the brake-equipped elevator car and / or to hold it stationary on the stationary component. The brake-holding assembly is designed to attach the brake to the elevator car.

[0015] A second part of the braking device comprises the load measuring device and the load measuring device support assembly. The load measuring device is designed to measure loads or forces acting on a part of the load measuring device referred to herein as the force transmission element. The load measuring device support assembly is configured to mount the load measuring device to the elevator car.

[0016] The two parts of the braking device are not only designed for different functionalities, but are also attached or held to the elevator car in different ways due to the different design of their respective holding arrangements.

[0017] On the one hand, the brake and the brake-holding arrangement are designed in such a way that the brake is deliberately not fixed absolutely stationary to the elevator car by means of the brake-holding arrangement, but can be displaced at least slightly relative to the elevator car, in particular in a direction of the force exerted by the brake, i.e. typically a direction in which the elevator car moves during its travel or a direction opposite thereto. In other words, the brake-holding arrangement, together with the brake attached to it, can move relative to the elevator car within a certain tolerance range or a certain play along the direction of car movement. The tolerance range can be, for example, a few tenths of a millimeter, in particular, for example, less than 1 mm.

[0018] On the other hand, the load measuring device and the load measuring device holding arrangement are designed in such a way that the load measuring device is firmly fixed to the elevator car by means of the load measuring device holding arrangement at least in the direction of force caused by the brake, but preferably also directions transverse to this direction of force, i.e. that the load measuring device is attached to the elevator car as rigidly and free of play as possible.

[0019] Accordingly, the brake, which is held on the elevator car with a certain degree of freedom of movement, can move at least slightly relative to the load measuring device rigidly fixed to the elevator car.

[0020] The force transmission element of the load measuring device is effectively connected to the brake. When the elevator car, including the rigidly coupled load measuring device, moves relative to the brake, which is held stationary to the stationary component of the elevator system when activated, the relative movement of the brake relative to the load measuring device transmits a force via the force transmission element to a suitable counter element of the load measuring device. This force can be measured by the load measuring device.

[0021] Accordingly, the load measuring device can measure forces acting on the elevator car, particularly in its direction of movement, i.e., typically in the vertical direction. In particular, load changes in the elevator car can be determined using the load measuring device.

[0022] However, the load measuring device and the brake should not be effectively connected to each other solely via the load measuring device's connecting force transmission element. Additionally, the load measuring device holding arrangement that holds the load measuring device and the brake holding arrangement that holds the brake should be connected to each other via a web arrangement.

[0023] This web arrangement should be configured such that the majority of the forces acting between the brake and the load measuring device are transmitted via the web arrangement rather than the force transmission element of the load measuring device. In particular, the web arrangement should be configured such that, for example, in the event of a failure of the force transmission element, the entire forces acting between the brake and the load measuring device can be transmitted solely via the web arrangement without the web arrangement tearing.

[0024] The web arrangement should be configured such that the load-measuring device holding arrangement and the brake holding arrangement are connected to one another in such a way that, at least when the applied forces are not excessive, the web arrangement predominantly deforms only elastically, i.e., no irreversible plastic deformation is caused. In particular, as explained in more detail below, only elastic deformations should occur in the web arrangement under forces that approximately correspond to the weight of the elevator car, including its maximum permissible payload.

[0025] The fact that the load measuring device holding arrangement is elastically deformably connected to the brake holding arrangement via the web arrangement ensures, among other things, that only a small portion of the forces generated between the brake and the load measuring device during their relative movement actually acts on the load measuring device. Accordingly, the load measuring device can be designed to be weaker than would be the case if the entire force were transferred to it.

[0026] Because the web arrangement mainly deforms elastically during force transmission, the forces transferred to the load measuring device can always be essentially proportional to the total forces acting between the brake and the elevator car.

[0027] Ultimately, the load measuring device can be used to measure the forces acting on the elevator car or the load changes caused in the elevator car very accurately and reproducibly, despite its relatively weak mechanical design.

[0028] According to one embodiment, the brake and the brake holding arrangement are configured such that the brake can be held on the elevator car by means of the brake holding arrangement such that the brake can be displaced relative to the elevator car up to a maximum of a predetermined position in the direction of force caused by the brake.

[0029] In other words, the brake holding arrangement can be designed in such a way that the brake attached to it can be mounted on the elevator car with a certain amount of play, allowing the brake to be easily moved relative to the elevator car within a tolerance range due to the forces generated when the brake is activated. However, the tolerance range should be clearly limited so that the brake cannot be displaced relative to the elevator car beyond a maximum specified position.

[0030] For example, one end of the tolerance range can be realized by a mechanical stop provided on the brake holding arrangement, up to which a fixing element rigidly coupled to the elevator car can be displaced relative to the brake holding arrangement, but beyond which the fixing element cannot be moved.

[0031] This can, for example, ensure that the brake can move slightly relative to the elevator car under relatively small forces, for example, up to the weight of the elevator car to be held. However, when significantly higher forces occur, such as those that can occur in the event of an emergency braking, the relative movement between the brake and the elevator car is limited to the maximum specified position by the provided stop. This can, among other things, increase the reliability of the braking functionality of the proposed braking device.

[0032] In particular, according to one embodiment, the brake holding arrangement can have elongated holes whose longitudinal direction extends parallel to the direction of force caused by the brake and through which fixing elements held stationary on the elevator car can extend in order to hold the brake holding arrangement on the elevator car.

[0033] In other words, two or more elongated holes may be provided in the brake holding arrangement through which fixing elements such as screws or bolts can pass, which are firmly connected to the elevator car.

[0034] An elongated hole can be an elongated through-opening that has larger dimensions in a direction parallel to the direction of force exerted by the brake, i.e., in a longitudinal direction, than in a direction transverse thereto, i.e., in a width direction. For example, the dimensions in the width direction can substantially correspond to those of the fixing element extending through the elongated hole, resulting in a positive fit in the width direction, whereas the dimensions in the length direction can be at least slightly larger than those of the fixing element, allowing the fixing element to move along the force direction within a tolerance range defined by the elongated hole.

[0035] The longitudinal ends of the slot act as a mechanical limit for the relative movement of the brake in the longitudinal direction. This means that the longitudinal ends form a mechanical stop that determines the position to which the brake and the elevator car can be moved relative to each other.

[0036] Accordingly, during an emergency braking, for example, the elevator car, with its fixing elements extending through the slots in the brake holding assembly, can move relative to the brake up to the maximum length of the slots. Further displacement is prevented by the resulting positive locking between the fixing elements and the ends of the slots. Accordingly, the high forces that occur, for example, during an emergency braking, can be transmitted between the brake and the elevator car via the fixing elements and the brake holding assembly.

[0037] According to one embodiment, the web arrangement is arranged, dimensioned and configured such that the web arrangement deforms essentially exclusively elastically when a force is transmitted between the brake holding arrangement and the load measuring device holding arrangement, which force corresponds to a weight force of the elevator car including a maximum permissible payload of the elevator car.

[0038] In other words, the web arrangement between the brake holding arrangement and the load measuring device holding arrangement can extend in such a way that it only experiences elastic deformation under forces that typically occur during normal operation of the elevator system, for example when the elevator car is to be held at a floor.

[0039] For this purpose, several different influencing variables can be suitably selected. For example, the spatial arrangement of the web arrangement, i.e. in particular its position, orientation and / or direction of extension, can affect its mechanical load-bearing capacity and / or its elastic deformability. Furthermore, the dimensioning of the web arrangement, i.e. in particular its cross-section, width, length, height, etc., can affect the load-bearing capacity and / or elastic deformability of the web arrangement. Furthermore, other configuration parameters such as the material used, processing performed during production, etc., can influence the load-bearing capacity and / or elastic deformability of the web arrangement.All of these parameters can be suitably selected so that the web arrangement is configured, for example depending on the properties of the elevator car (e.g. its weight and payload) and / or depending on the requirements of the entire elevator system (e.g. safety requirements regarding braking processes), to react to forces acting on it during normal operation of the elevator system only with an elastic deformation, but without plastic deformation.

[0040] In particular, according to one embodiment, the web arrangement can be arranged, dimensioned and configured such that the web arrangement deforms by less than 1 mm, preferably less than 0.5 mm and more preferably only between 0.05 mm and 0.3 mm, in the direction of the force caused by the brake when a force is transmitted between the brake holding arrangement and the load measuring device holding arrangement, which force corresponds to a weight force of the elevator car including a maximum permissible payload of the elevator car.

[0041] In other words, the elevator car should be able to move slightly relative to the brake during braking. However, the extent of this relative movement should be limited by the specifically selected configuration of the web arrangement so that, under normal circumstances, no relative movements of, for example, more than 0.5 mm occur. For many applications, it may even be advantageous if the web arrangement normally only allows relative movements of less than 0.2 mm.

[0042] In particular, the normally permissible relative movements should be smaller than the tolerance range within which the elevator car can move relative to the brake before the elevator car is prevented from further relative movement upon reaching a maximum permissible relative movement at a predetermined position, for example, by its fixing element striking the end of the elongated hole. In other words, due to its mechanical configuration, the web arrangement should preferably only allow relative movements between the elevator car and the brake that are shorter than, for example, the tolerance range specified by the elongated holes of the brake holding arrangement.

[0043] According to one embodiment, it may be particularly advantageous if the web arrangement extends at least in a partial area transversely to the direction of force caused by the brake.

[0044] If the web assembly between the brake support assembly and the load measuring device support assembly extended over its entire length parallel to the direction of force exerted by the brake, relative displacements between the two support assemblies could only occur if the web assembly itself could elastically change its length. However, this can be difficult with materials such as metals, which must be used for the web assembly to withstand the forces acting on it.

[0045] The aim is therefore to have the web arrangement run transversely to the direction of force exerted by the brake, at least in one partial area. The web arrangement can extend linearly over its entire length and at an angle to the direction of force exerted. Alternatively, the web arrangement can have curvatures and run at an angle to the direction of force exerted only in partial areas. In the partial areas running at an angle to the direction of force, the forces acting during braking can cause the web arrangement to bend instead of elongating the entire web arrangement, so that the two holding assemblies located at opposite ends of the web arrangement can move relative to one another in the direction of force. The local bending of the web arrangement can occur through elastic deformation if the web arrangement is suitably designed, in particular with a suitable orientation, a suitable cross-section and / or a suitable choice of material for the web arrangement.

[0046] According to one embodiment, the brake holding arrangement, the load measuring device holding arrangement, and the web arrangement are formed integrally with a common component. For example, the brake holding arrangement, the load measuring device holding arrangement, and the web arrangement can be formed integrally with a common stamped sheet metal part.

[0047] In other words, a single component, such as a sheet metal stamped into a suitable shape, can form both the brake holding arrangement and the load measuring device holding arrangement as well as the web arrangement extending between them.

[0048] The entire component can be easy to manufacture and can be adapted to the forces to be absorbed and transmitted, for example by a suitable choice of a sheet metal used, in particular with regard to the thickness of the sheet metal and the material of the sheet metal.

[0049] The one-piece construction of all areas of such a component, for example, prevents increased wear at weak points, which would otherwise occur at the transitions between segments of a multi-part component. The one-piece component can also withstand repeated mechanical loads over the long term.

[0050] Options can be created in both mounting assemblies to allow them to be secured to the elevator car. In particular, for example, round holes can be provided on the load measuring device mounting assembly to allow it to be secured to the elevator car with bolts or screws. Slotted holes can be provided on the brake mounting assembly, through which bolts or screws can also extend. Both the round holes and the slotted holes can be punched into the sheet metal forming the mounting assemblies.

[0051] According to one embodiment, the force transmission element can be connected to a counter element of the load measuring device fixed to the load measuring device holding arrangement via a strain gauge.

[0052] In other words, a strain gauge can be used to measure the forces acting on the load measuring device via the force transmission element. Thus, the strain gauge can be used to measure the forces acting between the brake holding assembly and the load measuring device holding assembly when the brake is activated, and thus ultimately the forces acting between the activated brake and the elevator car being braked by it. Using a strain gauge for this task enables a very robust design of the load measuring device. Furthermore, the strain gauge enables the acting forces to be measured very precisely and reproducibly.

[0053] According to one embodiment, the load measuring device can be configured to generate an electrical signal which represents the force acting on the force transmission element.

[0054] For example, the load measuring device can be equipped with sensors that can monitor physical parameters, allowing conclusions to be drawn about the forces acting on the force transmission element. The sensors can generate electrical signals based on the monitored physical parameters. Such electrical signals can be easily forwarded and transmitted, for example, to a control system of the elevator system or an external monitoring device. Based on the signals, conclusions can then be drawn about the forces acting on the elevator car. For example, this can be used to inform the control system of the elevator system about the payload currently in the elevator car, allowing the control system to control the drive device according to the load.

[0055] According to one embodiment, the brake of the described braking device can be configured as a holding brake to hold the elevator car stationary against its weight during a stop. In particular, it may be preferable to additionally configure the brake as a safety brake to brake the elevator car in an emergency in the event of a free fall.

[0056] In other words, the brake should at least be designed in such a way that it can be used to hold the elevator car stationary on the stationary component of the elevator system that interacts with the brake, for example, on a guide rail, while the elevator car is stopped at a floor, for example. As such a holding brake, the brake can prevent the elevator car from moving due to load changes when passengers enter or exit the elevator car.

[0057] In addition, it may be advantageous to design the brake to be even more resilient so that it can also act as an emergency brake. In this case, the brake should be configured to be able to exert very high forces between the elevator car and the stationary component in order to be able to decelerate the elevator car to a standstill over a short distance, for example if all of the supporting elements holding it should break and the elevator car should fall freely. In order to be able to reliably transmit the very high forces that briefly occur during such an emergency brake from the brake to the elevator car, the web arrangement can, on the one hand, be configured to be sufficiently stable so that it does not break under the high forces, although plastic deformation of the web arrangement may be permissible in such exceptional cases.On the other hand, the brake holding arrangement itself can be designed and attached to the elevator car, for example by appropriately dimensioning its elongated holes, in such a way that it remains reliably held to the elevator car in the event of an emergency braking action.

[0058] By using a braking device according to an embodiment of the first aspect of the invention, in an elevator installation according to an embodiment of the second aspect of the invention, an elevator car on which the brake holding arrangement and the load measuring device holding arrangement of the braking device are held can reliably interact with its brake, for example, with the guide rail in order to be able to brake the elevator car.

[0059] Additionally, within the scope of a method according to an embodiment of the third aspect of the invention, the braking device can be used to measure the current load acting on the elevator car. In particular, temporary load changes can be measured.

[0060] For example, the brake of the braking device can be activated while the elevator car is gradually stopped at a floor and is stationary. The brake can, for example, only be activated after the elevator car has been stopped at that floor by appropriately controlling the drive device. Alternatively, the brake can be used to actively decelerate a movement of the elevator car to a standstill, whereby the brake can then remain activated during the standstill.

[0061] The activated brake can prevent the elevator car from moving during a stop at a floor, for example, when passengers are boarding or disembarking. However, the boarding or disembarking of passengers causes a load change in the elevator car. When using the braking device described here, its load measuring device can be used to determine such load changes. This can be used, among other things, to detect overcrowding in the elevator car and thus overload.

[0062] Alternatively or additionally, according to an embodiment of the fourth aspect of the invention, a load change in the car can be measured using the described method and the information obtained can be used to adjust the force exerted by the drive device on the elevator car in such a way that the measured load change is compensated.

[0063] In other words, the load measuring device can first be used to measure how much the elevator car becomes heavier or lighter as passengers board or disembark. Without appropriate countermeasures, the change in load would cause the elevator car to suddenly sink downwards or slide upwards when the holding brake is subsequently released, as the elastic suspension elements that hold the elevator car would lengthen or shorten due to the change in load. By measuring the change in load in the elevator car with the load measuring device, the drive system can be controlled accordingly in order to adapt the force acting on the suspension elements before the holding brake is released, so that the elevator car does not sink or slide upwards when the holding brake is released.The process described can also be referred to as pre-torqueing, which is a preliminary adjustment of the torque to be produced by the drive device.

[0064] According to one embodiment, the described method can be implemented particularly easily if, before the load change occurs, a force measured by the load measuring device is used as a reference force. The force exerted on the elevator car can then be adjusted after the brake is activated and after the load change in the elevator car has occurred such that the load measuring device measures a force corresponding to the reference force.

[0065] In other words, even before the brake of the braking device is activated, and even before an elevator door is opened and passengers can board or disembark, the load measuring device can determine a current value of the force measured by the device and store it as a reference value. If a subsequent load change occurs within the elevator car due to a change in the number of passengers, this can be detected by the load measuring device.

[0066] However, it is not necessary to perform an absolute measurement of the forces caused by the load changes and use this to determine the control signals that need to be sent to the drive device in order to adjust the torque it causes to compensate for these load changes. Instead, the drive device can simply be controlled to successively change its torque. At the same time, it is possible to monitor how the current force measured by the load measuring device changes. If this corresponds to the initially determined reference value, this means that the torque caused by the drive device is adjusted appropriately to compensate for the interim load change, so that the brake can be released without a sudden jerky change in the position of the elevator car.

[0067] Furthermore, the device and the methods described above and below can be used to ensure that no maintenance technician is still in the car. For example, before switching from normal operation to maintenance mode, the car weight can be measured and then compared with a value measured after the maintenance work before switching back to normal operation. If a deviation is found, switching back to normal operation can be prevented. This is particularly advantageous in elevator systems that have no headroom, since it is important to avoid the elevator system being in normal operation when people are in the shaft.In contrast to a conventional load measurement in the floor of the cabin, where a person is only detected when their weight rests on the cabin floor, but not when the person is standing on the cabin roof, the load measurement at the brake of the cabin, as described above and below, allows such an application.

[0068] It should be noted that some of the possible features and advantages of the invention are described herein with reference to different embodiments of, on the one hand, the braking device itself and, on the other hand, the elevator installation equipped therewith, as well as a use of this braking device for measuring the load acting on the elevator car or for adjusting a force to be exerted by the drive device on the elevator car in response to a load change. A person skilled in the art will recognize that the features can be suitably combined, adapted, or exchanged within the scope of the appended claims to achieve further embodiments of the invention.

[0069] Embodiments of the invention will now be described with reference to the accompanying drawings, wherein neither the drawings nor the description are to be construed as limiting the invention. Fig. 1 shows a rough schematic of an elevator system according to an embodiment of the present invention. Fig. 2 shows a rough schematic of an elevator system according to an alternative embodiment of the present invention. Fig. 3 shows a perspective view of a braking device according to an embodiment of the present invention.

[0070] The figures are merely schematic and not to scale. The same reference numerals designate the same or equivalent features in the various figures.

[0071] Fign. 1 and 2 show differently designed elevator systems 1 with a braking device 15 according to two embodiments of the present invention. In Fig. 3 a concrete embodiment of the braking device 15 is shown larger and with more details.

[0072] The Fig. 1 The elevator system 1 shown comprises an elevator car 3, which can be held by, for example, rope-like or belt-like support means 5 and displaced in an elevator shaft 11. For this purpose, the support means 5 can be displaced by a drive device 7. The drive device 7 is controlled by a controller 9. During its displacement, the elevator car 3 is guided on both sides along at least one guide rail 13 serving as a stationary component 14.

[0073] In particular, in order to keep the elevator car 3 stationary during a stop at a desired position, such as at a floor, the elevator car 3, after being moved to the desired position by the drive device 7, can be temporarily fixed to the stationary guide rails 13 by means of brakes 17 provided on its braking devices 15. Each of the brakes 17 is attached, for example, to a frame of the elevator car 3 by means of brake holding assemblies 19.

[0074] At least one of the braking devices 15 further comprises a load measuring device 21. The load measuring device 21 comprises 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 may comprise a sensor, for example in the form of a strain gauge 27, by means of which a force acting on the load measuring device 21 between its force transmission element 25 and its counter element 29 can be measured. The load measuring device 21 may, for example, comprise evaluation electronics in its counter element 29, by means of which the measurement parameters prevailing at the sensor can be converted into electrical signals. The load measuring device 21 is also attached to the elevator car 3 via a load measuring device holding arrangement 23.

[0075] Fig. 2 shows a further embodiment of an elevator installation 1 according to the invention. The braking device 15 is shown only schematically in this case and can be designed in a similar way to the one shown in Fig. 1 illustrated embodiment. 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. In such an embodiment, the traction and suspension are separate, i.e., two traction support means 4 (below the car) and two suspension support means 6 (above the car) are used.

[0076] A braking device 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 tensioned by the weight of the elevator car 3, can be avoided.

[0077] It also proves advantageous, in such an elevator system 1, to integrate the load measurement into the braking device 15 provided on the elevator car 3, rather than, as is usually the case, in the suspension element fastenings. Load measurement via the suspension elements 6 is difficult in such an elevator system 1, since the pretensioning of the traction elements 4 causes an unknown variable to influence the forces in the suspension elements 6. In order to perform a load measurement on the traction elements 4, a sensor would have to be attached to both the traction elements 4 and the suspension element 6. In order to achieve accurate measurement results even with an uneven load distribution in the elevator car 3, the measurement would have to be performed on both sides of the elevator car 3. A total of four sensors would therefore have to be installed.

[0078] With the load measurement on the braking device 15, a reliable measurement can be realized with only two sensors.

[0079] 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).

[0080] In one embodiment, the load measurement may be present only on one braking device 15.

[0081] As particularly in Fig. 3 As can be seen, the load measuring device holding arrangement 23 and the brake holding arrangement 19 are mechanically connected to one another via a web arrangement 31.

[0082] A plurality of elongated holes 35 are formed in the brake holding arrangement 19. A longitudinal direction of the elongated holes 35 is essentially parallel to a force direction 39 in which a force exerted by the brake 17 is directed. The force direction 39 essentially corresponds to the direction of movement of the elevator car 3 and is thus essentially vertical. The length of the elongated holes 35 can, for example, be approximately 0.5 mm greater than their width. The plurality of elongated holes 35 are arranged linearly one above the other along the force direction 39. A fixing element 36, for example in the form of a bolt or a screw, can extend through each of the elongated holes 35 and can be fixed to the elevator car 3 or its frame.The brake holding arrangement 19 can thus be held on the elevator car 3 via the fixing elements 36, but can be moved slightly vertically relative to the elevator car 3 by displacing the fixing elements 36 within the elongated holes 35.

[0083] The load measuring device holding arrangement 23 has a plurality of round holes 33. Fixing elements (not shown) can in turn run through the round holes 33, via which the load measuring device holding arrangement 23 can be fastened to the elevator car 3 or to its frame essentially without play.

[0084] Accordingly, the brake 17 held by the brake holding arrangement 19 can shift slightly along 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 caused by activating the brake 17.

[0085] Such a relative displacement causes, among other things, a deformation of the web arrangement 31. The web arrangement 31 is arranged, dimensioned and configured in such a way that this deformation is generally elastic, at least as long as the brake 17 only causes forces that are required to hold the elevator car 3 and its payload, for example during a stop at a floor.

[0086] However, the relative displacements between the brake 17 and the car 3 caused when the brake 17 is activated can also be used to measure loads or load changes currently acting on the elevator car 3 with the aid of the load measuring device 21.

[0087] For this purpose, in the example shown, on the one hand, the counter element 29 of the load measuring device 21 is firmly connected, for example, screwed, to the load measuring device holding arrangement 23. On the other hand, the force transmission element 25 is coupled, for example, to a part of the brake holding arrangement 19 and thus effectively connected to the brake 17. With the aid of electronics arranged, for example, in the counter element 29 (not shown), mechanical stresses, such as those that arise in the strain gauge 27 arranged between the force transmission element 25 and the counter element 29 due to the forces caused by the relative displacement, can be measured. The electronics can then generate an electrical signal, which can serve as a measure of the force experienced by the load measuring device 21.

[0088] The braking device 15 can thus not only be used with its brake 17 to brake the elevator car 3, but can also be used with its load measuring device 21 to measure a load acting on the elevator car 3.

[0089] During operation of the elevator system 1, the elevator car 3 can be moved to a floor, for example, using the drive device 7. To prevent the elevator car 3 from subsequently moving up or down due to the resulting load changes when passengers get on and off, the brake 17 of the braking device 15 can be activated, for example, via a control line 37, before the car doors are opened.

[0090] Before or at least before a load change can occur in the elevator car 3, i.e., for example, before the car door is opened, a force currently acting between the brake 17 and the elevator car 3 can be measured using the load measuring device 21. In general, this force can be zero, for example, in particular in the event that 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, in the event that the brake 17 was used additionally to brake the movement of the elevator car 3, this force can also be non-zero. This previously measured force can be saved as a reference value.

[0091] As soon as load changes occur during the subsequent boarding and disembarking of passengers in the cabin, these changes 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 cabin 7 via the support means 5 by means of targeted control of the drive device 7 in such a way that the load changes that have occurred in the meantime are compensated.

[0092] 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 again corresponds to the previously determined reference value.

[0093] In both cases, it can be ensured that changed load conditions within the elevator car 3 are compensated for by appropriately retensioning or relaxing the support means 5 using the drive device 7 in such a way that the entire elevator car 3, including its temporarily changed payload, is again held by the support means 5. In this state, the brake 17 can be released without the elevator car 3 subsequently moving jerkily. Finally, it should be noted that terms such as "having," "comprising," etc., do not exclude other elements or steps, and terms such as "a" or "an" do not exclude a plurality.Furthermore, it should be noted that features or steps 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, as long as the combination remains within the scope of the appended claims. Reference signs in the claims are not to be considered as limitations.

Claims

1. Braking apparatus (15) for braking a displaceable elevator car (3) of an elevator installation (1) and for measuring load changes caused in the elevator car (3), wherein the braking apparatus (15) has: a brake (17) for braking the elevator car (3) relative to a stationary component (14) of the elevator installation (1); a brake holding arrangement (19) for holding the brake (17) on the elevator car (3); a load measuring device (21) having a force transmission element (25) for measuring a force acting on the force transmission element (25); a load measuring device holding arrangement (23) for holding the load measuring device (21) on the elevator car (3); wherein the brake (17) and the brake holding arrangement (19) are configured such that the brake (17) is to be held on the elevator car (3) by means of the brake holding arrangement (19) in such a way that the brake (17) can be displaced relative to the elevator car (3) in a force direction (39) generated by the brake (17); wherein the load measuring device (21) and the load measuring device holding arrangement (23) are configured such that the load measuring device (21) is to be held on the elevator car (3) by means of the load measuring device holding arrangement (23) in such a way that the load measuring device (21) is fixed relative to the elevator car (3) in the force direction (39) generated by the brake (17); wherein the force transmission element (25) of the load measuring device (21) is operatively connected to the brake (17) in order to be able to measure a force acting between the brake (17) and the load measuring device (21) due to a relative displacement of the brake (17) relative to the load measuring device (21); characterized in that the load measuring device holding arrangement (23) and the brake holding arrangement (19) are connected to one another in an elastically deformable manner via a connecting piece arrangement (31).

2. Braking apparatus according to claim 1, wherein the brake (17) and the brake holding arrangement (19) are configured such that the brake (17) can be held on the elevator car (3) by means of the brake holding arrangement (19) in such a way that the brake (17) can be displaced relative to the elevator car (3) at most up to a predetermined position in the force direction (39) generated by the brake (17).

3. Braking apparatus according to either of the preceding claims, wherein the brake holding arrangement (19) has slots (35), the longitudinal direction of which extends parallel to the force direction (39) generated by the brake (17) and through which fixing elements (36) held stationary on the elevator car (3) can extend in order to hold the brake holding arrangement (19) on the elevator car (3).

4. Braking apparatus according to any of the preceding claims, wherein the connecting piece arrangement (31) is arranged, dimensioned, and configured such that the connecting piece arrangement (31) deforms substantially only elastically when a force which corresponds to a weight of the elevator car (3) including a maximum permissible payload of the elevator car (3) is transmitted between the brake holding arrangement (19) and the load measuring device holding arrangement (23).

5. Braking apparatus according to any of the preceding claims, wherein the connecting piece arrangement (31) is arranged, dimensioned, and configured such that the connecting piece arrangement (31) deforms by less than 1 mm in the force direction (39) generated by the brake (17) when a force which corresponds to a weight of the elevator car (3) including a maximum permissible payload of the elevator car (3) is transmitted between the brake holding arrangement (19) and the load measuring device holding arrangement (23).

6. Braking apparatus according to any of the preceding claims, wherein the connecting piece arrangement (31) extends transversely to the force direction (39) generated by the brake (17), at least in a sub-region.

7. Braking apparatus according to any of the preceding claims, wherein the brake holding arrangement (19), the load measuring device holding arrangement (23), and the connecting piece arrangement (31) are formed in one piece by a common part.

8. Braking apparatus according to claim 7, wherein the brake holding arrangement (19), the load measuring device holding arrangement (23), and the connecting piece arrangement (31) are formed in one piece by a common stamped sheet metal part.

9. Braking apparatus according to any of the preceding claims, wherein the force transmission element (25) is connected via a strain gauge (27) to a counter-element (29) of the load measuring device (21) fixed to the load measuring device holding arrangement (23).

10. Braking apparatus according to any of the preceding claims, wherein the load measuring device (21) is configured to generate an electrical signal which represents the force acting on the force transmission element (25).

11. Braking apparatus according to any of the preceding claims, wherein the brake (17) is designed as a holding brake to hold the elevator car (3) stationary against its weight during a stop, and wherein the brake (17) is preferably also designed as a safety brake to brake the elevator car (3) in an emergency in the event of a free fall.

12. Elevator installation (1) having: an elevator car (3); a guide rail (13); and a braking apparatus (15) according to any of claims 1 to 11; wherein the elevator car (3) is displaceable along the guide rail (13); wherein the braking apparatus (15) is held on the elevator car (3) by means of the brake holding arrangement (19) thereof and the load measuring device holding arrangement (23) thereof; and wherein the brake (17) of the braking apparatus (15) is configured to interact with the guide rail (13) in order to brake the elevator car (3).

13. Method for measuring a load acting on an elevator car (3), wherein the method comprises: activating the brake (17) of a braking apparatus (15) according to any of claims 1 to 11 held on the elevator car (3) while the elevator car (3) is stationary; and measuring the load acting on the elevator car (3) using the load measuring device (21) of the braking apparatus (15).

14. Method for setting a force to be exerted by a drive device (7) on an elevator car (3) in response to a load change in the elevator car (3), wherein the method comprises: measuring the load change using a method according to claim 13; and setting the force exerted by the drive device (7) on the elevator car (3) in such a way that the measured load change is compensated for.

15. Method according to claim 14, wherein, before the load change occurs, a force measured by the load measuring device (21) is measured as a reference force; and wherein the force exerted on the elevator car (3) after activation of the brake (17) and after a load change has occurred in the elevator car (3) is set in such a way that the load measuring device (21) measures a force corresponding to the reference force.