Braking device for lift car and its use in a lift system and method

Abstract

The invention relates to a brake device (15) for braking a movable elevator car (3) of an elevator system (1) and for measuring load changes produced in the elevator car (3). The brake device (15) has: at least one brake (17), preferably two brakes (17), for braking the elevator car (3) relative to a stationary component (14) of the elevator system (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); and a load measuring device holding arrangement (23) for holding the load measuring device (21) on the elevator car (3).

Description

[0001] The present invention relates to a braking device for an elevator system, which can both brake a movable elevator car and measure load changes occurring in the elevator car. The invention further relates to an elevator system equipped with such a braking device. In addition, the invention relates to a method for measuring a load acting on an elevator car and a method for adjusting a force exerted by a drive unit 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. This movement of the elevator car is achieved by a drive unit that powers the supporting elements, such as ropes or belts, that hold the car in place. During its movement, the elevator car is usually guided by guide rails. To bring the elevator car to a stop at a desired floor, its movement is generally slowed down by appropriately controlling the drive unit.

[0003] When people enter or exit an elevator car stopped at a floor, the resulting load change can cause the supporting structures holding the car to elastically deform in their length. Consequently, the position of the elevator car relative to the floor can change slightly while it is stopped. To prevent a step from forming between the elevator car floor and the floor, this change in position was traditionally compensated for by a process called re-leveling. In this process, the drive unit deliberately shifts the supporting structures holding the elevator car to counteract the change in position. However, implementing such re-leveling requires complex measures.

[0004] Alternatively, it was suggested that a brake be installed directly on the elevator car, which could hold the car in position while it is stopped at a floor. However, this could lead to the problem that a change in the load inside the car during the stop could cause a sudden change in the car's position when the brake is subsequently released due to the altered 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-handling device for rope 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 describes a brake-load measuring system in which load cells interact with a brake. WO2021 / 084012 discloses a braking device for an elevator car with integrated load measurement and its use in an elevator system.

[0006] There may be a need for a braking device that can advantageously brake an elevator car and is also designed to measure load changes occurring in the elevator car. Furthermore, there may be a need for an elevator system equipped with such a braking device. Additionally, 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 on an elevator car by a drive unit in response to a load change in the elevator car.

[0007] Such a need can 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 movable elevator car of an elevator system and for measuring load changes induced 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 on 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 on the elevator car. The brake and the brake holding arrangement are designed such that the brake is held on 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 direction of force induced by the brake.The load measuring device and the load measuring device mounting assembly are configured such that the load measuring device is held on the elevator car by the load measuring device mounting assembly in such a way 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 measure any force generated by the load measuring device mounting assembly due to the relative displacement of the brake. The load measuring device mounting assembly and the load measuring device are designed and connected to the brake mounting assembly in such a way that a displacement of the brake in the direction of the force exerted by the brake generates a measuring force acting essentially perpendicular to the direction of the force exerted by the brake, which can be measured by the load measuring device.

[0009] According to a second aspect of the invention, an elevator system 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 movable 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 held 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] Possible features and advantages of embodiments of the invention can be considered, among other things and without limiting the invention, as being based on the ideas and findings described below.

[0012] In short, the basic concept of the braking device proposed herein can be seen as enabling two functionalities with a single device: braking the elevator car and measuring a change in load caused within the elevator car. For this purpose, the braking device is essentially constructed in two parts.

[0013] The 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 the movement of the elevator car or its weight, thus slowing the car's motion and / or holding it stationary against the component. The brake holding assembly is designed to mount the brake to the elevator car.

[0014] A second part of the braking device comprises the load measuring device and the load measuring device mounting 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 mounting assembly is configured to attach the load measuring device to the elevator car.

[0015] The two parts of the braking device are not only designed for different functionalities, but are also attached to or held in different ways on the elevator car due to the different design of their respective holding arrangements.

[0016] On the one hand, the brake and the brake mounting assembly are designed such that the brake is not absolutely fixed to the elevator car by means of the brake mounting assembly, but can be displaced at least slightly relative to the elevator car, particularly in the direction of the force exerted by the brake, i.e., typically in the direction in which the elevator car moves during its travel, or in the opposite direction. In other words, the brake mounting assembly, together with the brake attached to it, can move within a certain tolerance range or a certain amount of play along the direction of the car's movement relative to the elevator car. This tolerance range can be, for example, a few tenths of a millimeter, and in particular, less than 1 mm.

[0017] 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 fixed to the elevator car at least in the direction of force caused by the brake by means of the load measuring device holding arrangement, i.e. that the load measuring device is attached to the elevator car as rigidly and without play as possible.

[0018] Accordingly, the brake, which is held to the elevator car with a certain degree of freedom of movement, can move at least slightly relative to the load measuring device, which is rigidly fixed to the elevator car.

[0019] The force transmission element of the load measuring device is effectively connected to the brake. If the elevator car, along with the load measuring device rigidly coupled to it, moves relative to the brake (which, when activated, is held stationary on the stationary component of the elevator system), the relative movement of the brake relative to the load measuring device transmits a force (essentially proportional) via the force transmission element to a suitable counter-element of the load measuring device. This force can then be measured by the load measuring device.

[0020] Accordingly, the load measuring device can measure forces acting on the elevator car, particularly in its direction of movement, that is, typically in the vertical direction. In particular, load changes within the elevator car can be determined using the load measuring device.

[0021] The load measuring device mounting assembly and the load measuring device are designed and connected to the brake mounting assembly in such a way that, when the brake is displaced in the direction of force exerted by the brake relative to the elevator car, a force acting essentially perpendicular to the direction of force exerted by the brake is generated. The load measuring device mounting assembly and the load measuring device are designed such that the force can be measured by the load measuring device.

[0022] In other words, the load measuring device mounting arrangement and the load measuring device itself are designed such that the displacement of the brake generates a force (measuring force) acting perpendicular to this displacement, which can then be measured accordingly. The load measuring device mounting arrangement essentially rotates, or transforms, the force in its direction of action by 90°.

[0023] According to one embodiment, the load measuring device mounting arrangement is elastically deformable in such a way that, in the event of a relative displacement of the brake, the elastic deformation results in a measuring force that is essentially proportional to the braking force and the load. In particular, the measuring force is smaller than the braking force causing the relative displacement.

[0024] The previously described conversion effected by the holding arrangement can also result in damping caused by the load measuring device holding arrangement. This allows the measuring force to be changed in amplitude and direction.

[0025] This has the advantage that the force caused by the displacement undergoes a kind of filtering during conversion (damping + suppression of forces also acting in the direction of the displacement, but not via the brake). This allows the signal-to-noise ratio of the force (measured quantity) to be improved, i.e., increased. In particular, the effects of forces exerted on the cabin, for example by the load-bearing elements, can be attenuated or dampened before measurement at the load measuring device. The measurement can thus be simplified and improved.

[0026] According to one embodiment, the load measuring device holding arrangement is essentially trapezoidal and / or triangular in shape.

[0027] In particular, the load measuring device mounting arrangement can be designed as a substantially isosceles trapezoid. Preferably, the load measuring device mounting arrangement is designed as a double trapezoid, wherein the longer bases of the two trapezoids can be aligned. In particular, these two overlapping longer bases are arranged parallel to the direction of the force causing the brake displacement. Preferably, the trapezoidal parts are identical, especially as two identical isosceles trapezoids. Also preferably, the two longer bases of the trapezoids are not formed. In other words, the load measuring device is designed as a kind of double trapezoid, i.e., a polygon, wherein this polygon consists only of the shorter bases and the legs of the two trapezoids, with the two longer bases not formed.This has the advantage that the polygon can be deformed in the direction of the force caused by the brake.

[0028] A force exerted parallel to the overlapping longer bases, caused by the relocation of the brake, leads, due to the elastic deformation of the load measuring device holding arrangement, to a kind of shortening of the (fictitious) longer bases of the two trapezoids and thus to an increase in the angles at which the legs of the trapezoid stand to the longer base of the trapezoids, which in turn leads to an increase in the distance between the two shorter bases.

[0029] In a substantially comparable embodiment of the load measuring holding arrangement, at least one, preferably both, trapezoid(s) is replaced by a substantially triangular part(s).

[0030] In one embodiment, the load measuring device with the force transmission element is arranged between the two shorter base sides of the trapezoids, so that a change in the distance between the two shorter base plans can be measured by the load measuring device.

[0031] In one embodiment, the load measuring device with the force transmission element is arranged between two struts, each strut being attached to one of the four legs of the two trapezoids. Elastic deformation of the trapezoids leads to a displacement of the struts relative to each other, so that a load measuring device attached to the struts makes such a displacement measurable.

[0032] In one embodiment, the load measuring device is arranged in the load measuring device holding arrangement such that the force transmission element runs essentially perpendicular to the direction of force caused by the brake and is displaceable in this direction.

[0033] This makes it particularly easy to measure the force that changes in a direction of essentially 90° due to the deformation. Furthermore, the influence of forces acting in the direction of the brake force is reduced.

[0034] In one embodiment, the load measuring device mounting assembly comprises at least two fixing elements for holding the load measuring device mounting assembly to the elevator car. The fixing elements are arranged such that a line passing through the two fixing elements is substantially perpendicular to the direction of force exerted by the brake.

[0035] The aim is to firmly fix the load measuring device mounting assembly to the cabin in the direction of the acting force, so that any displacement of the brake, which is not fixedly attached to the cabin in this direction, results exclusively in elastic deformation of the load measuring device mounting assembly and not in any displacement. This is achieved particularly easily by means of two fixing elements, in particular screws or bolts, which are mounted on a line running perpendicular to the direction of the force.

[0036] In other words, the brake mounting arrangement can be designed in such a way that the attached brake can be mounted on the elevator car with a certain amount of play, so that the brake can move slightly relative to the elevator car within a tolerance range due to the forces exerted when the brake is activated.

[0037] This can, for example, cause the brake to move slightly relative to the elevator car even under relatively minor forces, such as the weight of the elevator car being held.

[0038] In particular, according to one embodiment, the brake holding arrangement can have a type of elongated hole whose longitudinal direction extends parallel to the direction of force exerted by the brake and through which fixing elements fixed to the elevator car can extend in order to hold the brake holding arrangement on the elevator car.

[0039] In other words, the brake holding arrangement may include one or more elongated holes (open or closed) through which fixing elements such as screws or bolts can pass, which are firmly connected to the elevator car.

[0040] A slotted hole can be an elongated through-hole 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 perpendicular to it (i.e., in a lateral direction). For example, the lateral dimensions can essentially correspond to those of the fixing element passing through the slotted hole, resulting in a positive fit in the lateral direction, whereas the lateral dimensions can be at least slightly larger than those of the fixing element, allowing the fixing element to move within a tolerance range defined by the slotted hole along the direction of force.

[0041] The longitudinal ends of the slot may or may not be present. They act as a mechanical limit to the relative movement of the brake in the longitudinal direction. In other words, the longitudinal ends form a mechanical stop that defines the position to which the brake and the elevator car can be moved relative to each other.

[0042] Accordingly, during an emergency stop, for example, the elevator car, with its fixing elements extending through the elongated holes of the brake mounting assembly, can only move relative to the brake up to the longitudinal ends of the elongated holes. Further movement is prevented by the resulting positive locking between the fixing elements and the ends of the elongated holes. Therefore, the high forces that occur during an emergency stop can be transmitted between the brake and the elevator car via the fixing elements and the brake mounting assembly.

[0043] According to one embodiment, the load measuring device holding arrangement is arranged, dimensioned and configured such that the load measuring device holding arrangement deforms essentially exclusively elastically when a force is transmitted between the brake holding arrangement and the load measuring device holding arrangement, which corresponds to a weight force of the elevator car including a maximum permissible payload of the elevator car.

[0044] In other words, the load measuring device holding arrangement can be designed, that is, dimensioned and / or shaped in terms of material and thickness, 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.

[0045] Several different influencing factors can be appropriately selected for this purpose. For example, the spatial arrangement of the load measuring device mounting assembly, 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 dimensions of the load measuring device mounting assembly, i.e., in particular its cross-section, width, length, height, etc., can affect the load-bearing capacity and / or elastic deformability of the mounting structure. Additional configuration parameters, such as the material used, machining operations performed during manufacturing, etc., can also influence the load-bearing capacity and / or elastic deformability of the load measuring device mounting assembly.All these parameters can be appropriately selected so that the load measuring device holding arrangement is configured, for example, depending on the properties of the elevator car (for example, its weight and payload) and / or depending on requirements for the entire elevator system (for example, safety requirements regarding braking operations), to react to forces acting on it during normal operation of the elevator system only with elastic deformation, but without plastic deformation.

[0046] In particular, according to one embodiment, the load measuring device holding 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 exerted by the brake when a force is transmitted between the brake holding arrangement and the load measuring device holding arrangement, which corresponds to a weight force of the elevator car including a maximum permissible payload of the elevator car.

[0047] 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 specific configuration of the load-measuring device / holding arrangement to such an extent that, under normal circumstances, no relative movements of, for example, more than 0.5 mm occur. For many applications, it can even be advantageous if the web arrangement normally allows only relative movements of less than 0.2 mm.

[0048] According to one embodiment, the brake mounting assembly and the load measuring device mounting assembly are formed integrally with a common component. For example, the brake mounting assembly and the load measuring device mounting assembly can be formed integrally from a stamped sheet metal part.

[0049] In other words, a single component, such as a sheet metal piece stamped into a suitable shape, can form both the brake mounting assembly and the load measuring device mounting assembly.

[0050] The entire component can be easy to manufacture and, for example, adapted to the forces to be absorbed and transmitted by a suitable choice of sheet metal, especially with regard to the thickness and material of the sheet metal.

[0051] By manufacturing all areas of such a component as a single piece, it is possible, for example, to avoid increased wear at weak points that would otherwise occur at the transitions between segments of a multi-part component. The single-piece component can also withstand repeated mechanical stresses over the long term.

[0052] 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.

[0053] 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 allows the measurement of the forces acting between the brake holding assembly and the load measuring device holding assembly when the brake is applied, and ultimately, the forces acting between the applied brake and the elevator car it is braking. Using a strain gauge for this task enables a very robust design of the load measuring device. Furthermore, the strain gauge allows for very precise and reproducible measurement of the acting forces.

[0054] According to one embodiment, the force transmission element and the counter element are each supported on a web that emerges from one of the legs of the essentially trapezoidal load measuring device mounting assembly. This allows for particularly easy attachment of the load measuring device to the load measuring device mounting assembly.

[0055] According to one embodiment, the load measuring device can be configured to generate an electrical signal that reflects the force acting on the force transmission element.

[0056] For example, the load measuring device can be equipped with sensors that monitor physical parameters, allowing conclusions to be drawn about the forces acting on the force transmission element. Depending on the monitored physical parameters, the sensors can generate electrical signals. These electrical signals can be easily transmitted and, for example, transferred to the elevator control system or an external monitoring device. Based on these signals, the forces acting on the elevator car can then be deduced. For instance, this can inform the elevator control system of the current payload in the car, enabling the control system to adjust the drive mechanism accordingly.

[0057] According to one embodiment, the brake of the described braking device can be configured as a holding brake to keep the elevator car stationary against its weight during a stop. In particular, it may be preferred to additionally configure the brake as a safety brake to bring the elevator car to an emergency stop in the event of a free fall.

[0058] In other words, the brake should be designed to hold the elevator car stationary against the stationary component of the elevator system that interacts with the brake, for example, a guide rail, while the elevator car is stopped at a particular floor. As such a holding brake, it prevents the elevator car from moving due to load changes when passengers enter or exit the elevator car.

[0059] Additionally, it can be advantageous to design the brake to be even more robust so that it can also function as a safety brake. In this case, the brake should be configured to generate very high forces between the elevator car and the stationary component, enabling the elevator car to be brought to a standstill over a short distance, even if all the supporting structures were to break and the car were to fall freely. To reliably transfer the very high forces that occur briefly during such a safety brake application from the brake to the elevator car, the load-measuring device / holding assembly can be configured to be sufficiently robust to prevent excessive plastic deformation under these high forces.

[0060] By using a braking device according to an embodiment of the first aspect of the invention, an elevator car in an elevator system according to an embodiment of the second aspect of the invention, on which the brake holding arrangement and the load measuring device holding arrangement of the braking device are held, can thus reliably interact with, for example, the guide rail with its brake in order to be able to brake the elevator car.

[0061] Additionally, the braking device can be used, within the framework of a method according to an embodiment of the third aspect of the invention, to measure the current load acting on the elevator car. In particular, temporary load changes can be measured.

[0062] For example, the brake of the braking device can be activated while the elevator car is being brought to a stop at a floor. The brake can be activated only after the elevator car has been brought to a stop at that floor by appropriately controlling the drive unit. Alternatively, the brake can be used to actively slow the elevator car's movement until it comes to a standstill, and the brake can remain activated during this standstill.

[0063] The activated brake prevents the elevator car from moving while stopped at a floor, for example, when passengers are boarding or alighting. However, passengers boarding or alighting cause a change in the load inside the elevator car. When using the braking device described herein, 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 an overload.

[0064] Alternatively or additionally, according to an embodiment of the fourth aspect of the invention, a change in load in the cabin 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 cabin in such a way that the measured change in load is compensated.

[0065] In other words, the load measuring device can first measure how much the elevator car becomes heavier or lighter due to passengers entering or exiting. Without appropriate countermeasures, this load change would cause the elevator car to jerk downwards or upwards when the holding brake is subsequently released, as the elastic load-bearing elements that support the elevator car would lengthen or shorten due to the load change. By measuring the load change in the elevator car with the load measuring device, the drive system can be controlled accordingly to adjust the force acting on the load-bearing elements appropriately even before the holding brake is released, thus preventing the elevator car from sagging or sliding upwards when the holding brake is released.The described process can also be referred to as a pre-torqued adjustment of the torque to be produced by the drive device.

[0066] According to one embodiment, the described method can be carried out particularly easily if a force measured by the load measuring device is used as a reference force before the load change occurs. The force exerted on the elevator car can then be adjusted after the brake is activated and the load change has taken place in the elevator car, such that the load measuring device measures a force corresponding to the reference force.

[0067] In other words, even before the brakes of the braking system are activated, and also before, for example, an elevator door is opened and passengers can enter and exit, the load measuring device can determine a current value of the force it measures and store this value as a reference. If a change in load then occurs within the elevator car due to a change in the number of passengers, this can be detected by the load measuring device.

[0068] However, it is not necessarily required to perform an absolute measurement of the forces caused by the load changes and derive the control signals from this measurement to be sent to the drive unit in order to adjust the torque it generates to compensate for these load changes. Instead, the drive unit can simply be controlled to successively change its torque. Simultaneously, the change in the current force measured by the load measuring device can be monitored. If this corresponds to the initially determined reference value, it means that the torque generated by the drive unit is appropriately adjusted to compensate for the load change that has occurred in the meantime, so that the brake can be released without a sudden, jerky change in the position of the elevator car.

[0069] Furthermore, the device and the procedures described above and below can be used to ensure that no maintenance technician is present in the cabin. For example, before switching from normal operation to maintenance mode, the cabin weight can be measured, and this value can then be compared with a value measured after the maintenance work before switching back to normal operation. If there is a discrepancy, switching back to normal operation can be prevented. This is particularly advantageous in elevator systems that do not have headroom, as it is essential to avoid the elevator operating in normal mode when people are in the shaft.Unlike conventional load measurement in the cabin floor, where a person is only detected when their weight is on the cabin floor but not when the person is standing on the cabin roof, load measurement at the cabin brake, as described above and below, allows such use.

[0070] It is 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 system equipped therewith, as well as to the 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 unit on the elevator car in response to a change in load. A person skilled in the art will recognize that the features can be suitably combined, adapted, or exchanged to arrive at further embodiments of the invention.

[0071] Embodiments of the invention are described below with reference to the accompanying drawings, whereby neither the drawings nor the description are to be interpreted as limiting the invention. Fig. 1 The diagram roughly schematically shows an elevator system according to one embodiment of the present invention. Fig. 2 The diagram roughly schematically shows 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.

[0072] The figures are schematic only and not to scale. Identical reference symbols in the different figures denote identical or equivalent features.

[0073] Fig. 1 and 2 Figure 1 shows elevator systems 1 with a braking device 15 in different configurations according to two embodiments of the present invention. Fig. 3 A specific embodiment of the braking device is shown 15, larger and with more details.

[0074] The in Fig. 1 The depicted elevator system 1 comprises an elevator car 3, which is held by, for example, rope-like or belt-like support elements 5 and can be moved in an elevator shaft 11. For this purpose, the support elements 5 can be moved by a drive unit 7. The drive unit 7 is controlled by a controller 9. During its movement, the elevator car 3 is guided on both sides by at least one guide rail 13, which serves as a stationary component 14.

[0075] In particular, to enable the elevator car 3 to remain stationary at a desired position, such as on a floor, during a stop, the elevator car 3, after being moved to the desired position by the drive unit 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.

[0076] At least one of the braking devices 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, 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 can, for example, have 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 by means of a load measuring device mounting assembly 23.

[0077] Fig. 2 Figure 1 shows a further embodiment of an elevator system 1 according to the invention. The braking device 15 is shown only schematically in this case and can be designed in detail similarly to that in Figure 1. Fig. 1 The illustrated embodiment. The elevator system 1 comprises an elevator car 3 and two counterweights 8. The elevator system 1 includes two drive units 7, which are arranged in the head of an elevator shaft 11. In this embodiment, the elevator system 1 further comprises two support elements 6 below the elevator car 3. These support elements 6 each extend from a lower end of the elevator car 3, via a deflection pulley at the pit floor, to a lower part of the respective counterweight 8.

[0078] A braking device 15, as described above and below, proves to be particularly advantageous when used in such an elevator system 1, since braking at the drive devices 7, i.e. via traction means 6, can be avoided.

[0079] It also proves advantageous to integrate the load measurement in the braking device 15 provided on the elevator car 3 in such an elevator system 1, and not to carry it out in the support material attachments as is otherwise usual.

[0080] Fig. 3 Figure 15 shows the brake device 15 in detail. The brake holding assembly 19 is designed with elongated recesses 34 (covered by washers of the fixing elements 36). One longitudinal direction of the recesses 34 is essentially parallel to a force direction 39 in which a force exerted by the brake 17 is directed. The force direction 39 corresponds essentially to the direction of movement of the elevator car 3 and is therefore essentially vertical. The length of the recesses 34 can, for example, be approximately 0.5 mm greater than their width. A fixing element 36 (with washer), for example in the form of a bolt or a screw, extends through each of the elongated recesses 34 and can be fixed to the elevator car 3 or to 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, initially especially exclusively vertically relative to the elevator car 3, by relocating the fixing element 36 within the elongated recess 34.

[0081] The load measuring device mounting assembly 23 has several round holes 33. Fixing elements 43 can pass through these round holes 33, allowing the load measuring device mounting assembly 23 to be attached to the elevator car 3 or its frame with virtually no play. In the illustrated embodiment, the round holes 33 are arranged on a line (not shown) that runs essentially perpendicular to the direction of force 39.

[0082] 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 exerted by activating the brake 17.

[0083] Such a relative displacement causes a deformation of the load measuring device holding arrangement 23. The load measuring device holding arrangement 23 is arranged, dimensioned and configured in such a way that this deformation usually occurs elastically, at least as long as the brake 17 only exerts forces that are required to hold the elevator car 3 and its payload, for example during a stop at a floor.

[0084] The load measuring device holding arrangement 23 is designed as an essentially double isosceles trapezoid (first trapezoid 24 and second trapezoid 26, see auxiliary lines). The trapezoids 24, 26 each consist only of the shorter base sides 28 / 30 and the legs 32, 38 and 40, 42 respectively, with the two longer base sides 44, 46 being purely hypothetical. The longer base sides 44 and 46 (also called the bases) of the two trapezoids lie on top of each other. These two overlapping longer base sides 44, 46 are arranged essentially parallel to the direction of force 39 that causes the displacement of the brake 17. The two trapezoids 24, 26 are designed as identical isosceles trapezoids.

[0085] The load measuring device 21 is arranged with the force transmission element 25 between two webs 48, 50. The first web 48 is connected to or formed with the leg 32 of the first trapezoid 24, which is located closer to the brake 17. The second web 50 is connected to or formed with the leg 40 of the second trapezoid 26, which is located closer to the brake 17. Elastic deformation of the trapezoids 24, 26 leads to a displacement of the webs 48, 50 relative to each other, so that the load measuring device 21, which is attached to the webs 48, 50, makes such a displacement measurable. The displacement is essentially proportional to the force acting in the direction of force 39 and caused by the displacement of the brake holding arrangement 19.

[0086] The load measuring device 21 and the force transmission element 25 are arranged in the load measuring device holding arrangement 23 via the webs 48, 50 such that the force transmission element 25 runs essentially perpendicular to the direction of force 39 caused by the brake 17 and is displaceable in this direction (indicated by arrow 40).

[0087] However, the relative displacements between the brake 17 and the cabin 3 caused when the brake 17 is activated can also be used to measure loads or load changes currently acting on the elevator cabin 3 using the load measuring device 21.

[0088] In the illustrated example, the counter element 29 of the load measuring device 21 is fixedly connected to the load measuring device mounting assembly 23, for example by screws. The force transmission element 25 is coupled, for example, to a part of the brake mounting assembly 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 arising in the strain gauge 27 located 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 that can serve as a measure of the force experienced by the load measuring device 21.

[0089] The braking device 15 can therefore not only be used with its brake 17 to brake the elevator car 3, but also with its load measuring device 21 to measure a load acting on the elevator car 3.

[0090] During operation of the elevator system 1, the elevator car 3 can, for example, be moved to a floor by the drive unit 7. To prevent the elevator car 3 from subsequently moving up or down due to load changes when passengers enter and exit, the brake 17 of the braking device 15 can be activated, for example, via a control line 37, before the car doors are opened.

[0091] 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, the 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, if the elevator car 3 was braked to a standstill solely by actuating the drive unit 7 and the brake 17 was only activated afterward. However, if the brake 17 was used additionally to decelerate the movement of the elevator car 3, this force can also be non-zero. This pre-measured force can be stored as a reference value.

[0092] As soon as load changes occur during the subsequent boarding and alighting of passengers in the cabin, these 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 load-bearing elements 5 by means of targeted control of the drive unit 7 in such a way as to compensate for the load changes that have occurred in the meantime.

[0093] Alternatively, the drive unit 7 can change the forces acting on the elevator car 3 via the load-bearing means 5 until the force currently measured by the load measuring device 21 again matches the previously determined reference value.

[0094] In In both cases, it can be ensured that changed load conditions within the elevator car 3 are compensated by suitable retensioning or loosening of the support means 5 using the drive unit 7, so that the entire elevator car 3 including its temporarily changed payload is again held by the support means 5. In In this state, the brake 17 can be released without the elevator car 3 moving jerkily.

[0095] Finally, it should be noted that terms such as "comprising," "encompassing," 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 from other embodiments described above. Reference numerals in the claims are not to be considered as limitations.

Claims

1. A braking apparatus (15) for braking a displaceable elevator car (3) of an elevator system (1) and for measuring load changes caused in the elevator car (3), wherein the braking apparatus (15) has: at least one brake (17), preferably two brakes (17), for braking the elevator car (3) relative to a stationary component (14) of the elevator system (1); a brake holding arrangement (19) for holding the brake (17) on the elevator car (3); a load measuring device (21) with 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 designed 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); and characterized in that the load measuring device holding arrangement (19) and the load measuring device (21) are designed and connected to the brake holding arrangement (19) such that, when the brake (17) is displaced in the force direction (39) generated by the brake relative to the elevator car (3), a measuring force (40) acting substantially perpendicular to the force direction (39) generated by the brake (17) is produced which is measurable by the load measuring device (21).

2. The braking apparatus according to claim 1, wherein the load measuring device holding arrangement (23) is elastically deformable such that, in the event of a relative displacement of the brake (17), the elastic deformation results in a measuring force (40) that is substantially proportional to the braking force and load, wherein the measuring force is in particular smaller than a braking force causing the relative displacement.

3. The braking apparatus according to any of the preceding claims, wherein the load measuring device holding arrangement (23) is designed to be substantially trapezoidal and / or triangular.

4. The braking apparatus according to any of the preceding claims, wherein the load measuring device (21) is arranged in the load measuring device holding arrangement (23) in such a way that the force transmission element (25) extends substantially perpendicular to the force direction (39) generated by the brake (17) and is displaceable in this direction.

5. The braking apparatus (15) according to any of the preceding claims, wherein the load measuring device holding arrangement (19) comprises at least two fixing elements (43) to hold the load measuring device holding arrangement (19) on the elevator car (3), wherein the fixing elements (43) are arranged such that a line running through the two fixing elements is substantially perpendicular to the force direction (39) generated by the brake (17).

6. The braking apparatus (15) according to any of the preceding claims, wherein the brake holding arrangement (19) has a slot (34), the longitudinal direction of which extends parallel to the force direction (39) generated by the brake (17) and through which the fixing element (36) held stationary on the elevator car (3) can extend in order to hold the brake holding arrangement (19) on the elevator car (3).

7. The braking apparatus (15) according to any of the preceding claims, wherein the load measuring device holding arrangement (23) is arranged, dimensioned, and configured such that the load measuring device holding arrangement (23) 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).

8. The braking apparatus (15) according to any of the preceding claims, wherein the load measuring device holding arrangement (31) is arranged, dimensioned, and configured such that the load measuring device holding arrangement (23) 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).

9. The braking apparatus (15) according to any of the preceding claims, wherein the brake holding arrangement (19) and the load measuring device holding arrangement (23) are formed in one piece by a common part.

10. The braking apparatus (15) according to any of the preceding claims, wherein the brake holding arrangement (19) and the load measuring device holding arrangement (23) are formed in one piece from a stamped sheet metal part.

11. The braking apparatus (15) according to any of the preceding claims, wherein the force transmission element (25) is connected via a strain gage (27) to a counter-element (29) of the load measuring device (21) fixed to the load measuring device holding arrangement (23).

12. The braking apparatus (15) according to claim 11, as dependent on claim 3, wherein the force transmission element (25) and the counter-element (29) are each supported on a connecting piece which protrudes from one of the legs of the substantially trapezoidal load measuring device holding arrangement (23).

13. The braking apparatus (15) according to any of the preceding claims, wherein the brake (17) is configured 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.

14. An elevator system (1) having: an elevator car (3); a guide rail (13); and a braking apparatus (15) according to any of claims 1 to 13; 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 its brake holding arrangement (19) and its load measuring device holding arrangement (23); and wherein the brake (17) of the braking apparatus (15) is configured to cooperate with the guide rail (13) in order to brake the elevator car (3).

15. A 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 13 held on the elevator car (3), while the elevator car (3) is stationary; and measuring the load acting on the elevator car (3) by means of the load measuring device (21) of the braking apparatus (15).

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