Safety device for a lift system
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- INVENTIO AG
- Filing Date
- 2026-01-06
- Publication Date
- 2026-08-06
Smart Images
Figure EP2026050107_06082026_PF_FP_ABST
Abstract
Description
[0001] 2021P00321WÖ
[0002] - 1 - Safety device for an elevator system
[0003] The present disclosure relates to safety devices for elevator systems, elevator systems, methods for operating elevator systems, and methods for constructing and / or modernizing elevator systems.
[0004] State-of-the-art elevator systems can incorporate a number of redundant and / or complementary safety devices to ensure safe operation. For example, the car speed is monitored and regulated. This ensures that the car speed, as well as related parameters such as acceleration and jerk, always remain within a safe and comfortable range for passengers inside the car. The operation of an elevator system according to its intended purpose of transporting people and / or goods is referred to as "normal operation," and a corresponding operating mode of the elevator is called "normal operating mode."
[0005] Under certain conditions, it may be necessary for a qualified professional, such as a service or repair technician, to operate an elevator in a different service mode. In this mode, the person is positioned on the elevator car roof and controls the elevator via a service control unit located there or that can be connected. For safe operation, the elevator car speed is generally lower than the typical speed during normal operation.
[0006] Maintaining a maximum car speed in service mode is of particular importance due to the specific conditions, especially the exposed position of the person on the car roof. Therefore, it may be necessary to monitor the car speed in service mode independently of the other elevator controls and to trigger an emergency stop or bring the car to a safe and rapid halt if a car speed limit is reached or exceeded. Furthermore, such monitoring may be required by law and / or be part of relevant safety standards. A separate monitoring of the car speed may also be necessary under other circumstances.
[0007] CN101844719B relates to a photosensitive sensor safety device for an elevator. 2021P00321WÖ
[0008] - 2 - The safety device is characterized in that it is equipped with a photosensitive sensor, a digital display unit for the electronic speed limiter, a left rope clamp jaw block, a right rope clamp jaw block, a left rope clamp wedge block, and a right rope clamp wedge block, each located in the machine room of an elevator and in the outer frame of an elevator car. All translucent openings or reflective surfaces are arranged at equal intervals either on a tensioning rope pulley or on the shaft wall of the elevator. When the elevator car travels up and down, a light signal emitted by a light source is projected onto or reflected by the photosensitive sensor. The sensor transmits the speed information of the elevator car to the electronic speed limiter, which continuously monitors the travel speed of the car.In the event of a deviation, the electronic speed limiter immediately triggers an early warning, an alarm, and the elevator's emergency braking system, providing timely warning and safely bringing the elevator car to a stop. The photosensitive sensor safety device eliminates the disadvantages of a mechanical speed limiter, such as rapid wear, difficult visual inspection during adjustment and speed measurement, and low measurement accuracy. The device is available in various designs and can be selected according to specific requirements.
[0009] KR1020040005576A concerns the speed limiter for elevators, which prevents the platform from falling and accelerating uncontrollably, as can be caused by a failure of the winch brake. Specifically, the main rope is wound up, or the main rope itself acts as a speed limiter for the elevator. The system detects when the platform is in a state where the door at the top or bottom of the platform is open and can stop the platform in this case.
[0010] It is a general objective of the present disclosure to address this need, as described below. Advantageously, only minor modifications are required compared to known elevator systems. Advantageously, an existing elevator system can be modified accordingly with comparatively little effort and / or cost. The following description primarily concerns, but is not limited to, the operation of an elevator system in a service mode.
[0011] According to one aspect, the present disclosure relates to a safety device for a 2021P00321WÖ
[0012] - 3 - Elevator system. The safety device comprises a speed limiter, the speed limiter being designed such that a rotating element of the speed limiter is driven by the elevator car during travel along a path and rotates at a rotational speed proportional to the elevator car speed. The rotating element has circumferentially alternating first and second optical features, the first and second optical features differing in their optical transmittance and / or reflectivity. The number of first and second optical features is the same.
[0013] The safety device further comprises a speed monitor, the speed monitor comprising a light barrier and an evaluation unit. The light barrier comprises an optical transmitter and an optical receiver, the optical transmitter and the optical receiver being arranged such that, upon rotation of the rotating element, the light flux from the optical transmitter to the optical receiver is periodically modulated by the first and second optical features. The optical receiver is designed to provide a receiver output signal that changes depending on the received light intensity. The evaluation unit is designed to compare a signal frequency of the receiver output signal with a cutoff frequency and to generate a speed stop signal when the signal frequency reaches and / or exceeds the cutoff frequency.At least the speed limiter, as well as the optical transmitter and the optical receiver, are designed for fixed installation in the elevator system.
[0014] According to one aspect, the present disclosure relates to an elevator system. The elevator system comprises a car, an elevator drive, and traction means, wherein the car and the elevator drive are coupled via the traction means such that the car can be moved vertically along a travel path by means of the elevator drive. The elevator system further comprises an elevator brake, wherein the elevator brake is designed to stop any movement of the car when activated and to hold the car in position. The elevator system further comprises an elevator control system with an electrical safety circuit, wherein the elevator control system is designed such that, in the event of an interruption of the electrical safety circuit, the elevator drive is de-energized and the elevator brake is activated. The elevator system further comprises a safety device according to one of the present disclosures – 2021P00321WÖ
[0015] - 4 -rung, wherein the evaluation unit is coupled to the safety circuit in such a way that the speed stop signal causes an interruption of the safety circuit.
[0016] According to one aspect, the present disclosure relates to a method for operating an elevator system as described in the present disclosure, the method comprising a continuous comparison of the signal frequency with the cutoff frequency and interruption of the safety circuit when the signal frequency exceeds the cutoff frequency. The method may, in particular, relate to operating the elevator system in a service mode.
[0017] According to one aspect, the present disclosure relates to a method for constructing an elevator system as disclosed. This method includes the installation of a speed monitor, such that the elevator system's speed limiter and the speed monitor together form a safety device as disclosed. The method further includes coupling, in particular a wired coupling, the evaluation unit with the elevator control system, so that during operation the speed stop signal is transmitted from the evaluation unit to the elevator control system.
[0018] According to one aspect, the present disclosure relates to the use of a safety device as disclosed for speed monitoring during the operation of an elevator system, in particular an elevator system as disclosed, in a service operating mode, wherein a continuous comparison of the signal frequency (f) with the cutoff frequency and interruption of the safety circuit takes place when the signal frequency (f) exceeds the cutoff frequency.
[0019] According to one method, the present disclosure relates to the use of an existing safety device in a retrofit and / or modernization process for a pre-existing elevator system, wherein the speed limiter of the safety device is part of the pre-existing elevator system.
[0020] A sophisticated safety device can be implemented cost-effectively, since a speed limiter is already present in typical, state-of-the-art elevator systems. Therefore, only the speed monitor is needed to implement a safety device as required. The installation of the safety device for a sophisticated elevator system is also comparatively inexpensive.
[0021] - 5 - with minimal time and cost expenditure. This can be done both as part of a new installation and as part of a modernization or retrofit, as explained in more detail below.
[0022] A fixed installation of at least the speed limiter, as well as the optical transmitter and optical receiver, means a fixed installation with respect to a stationary part of the elevator system, in particular an elevator shaft in which the car moves, and / or an elevator drive. The car, on the other hand, is not fixed in place. The speed limiter, and in particular the rotating element, can generally conform to the prior art. The safety device can be located in a machine room above the actual elevator shaft in which the car moves. In an elevator system without a machine room, the safety device, like an elevator drive, can be located in a shaft head above the travel path of the car. For the safety device, and in particular the speed limiter, the mounting locations and methods known from the prior art can generally be used.The evaluation unit can be located in close proximity to the optical transmitter and / or optical receiver and can optionally be integrated with the optical transmitter and / or optical receiver or housed in a common enclosure. Alternatively, the evaluation unit can be located separately, particularly in the case of an elevator control system, or it can be integrated into the elevator control system.
[0023] The fact that the rotating element is driven by the elevator car means that the car's motion is transferred to the rotating element, causing it to rotate. Therefore, the rotating element is not part of the power flow between the elevator drive and / or a typically present counterweight and the elevator car. Rather, the power flow to the rotating element runs through the elevator car.
[0024] In one embodiment, the first optical features allow the light to flow from the optical transmitter to the optical receiver, while the second optical features prevent the light from flowing from the optical transmitter to the optical receiver. In this way, the light is modulated in at least a substantially binary manner, so that the receiver provides an at least substantially binary output signal.
[0025] In one embodiment, the light barrier is a one-way light barrier, wherein the optical 2021P00321WÖ
[0026] - 6 - The transmitter and the optical receiver are arranged on a common axis, in particular parallel to an axis of rotation of the rotating element, on different sides of the rotating element.
[0027] In one embodiment, the rotating element comprises recesses, wherein the first optical features or the second optical features are defined by the recesses. The recesses can, in particular, be through openings. The other of the first and second optical features are defined circumferentially by the areas between the recesses.
[0028] In one embodiment, the recesses extend continuously in a direction parallel to the axis of rotation of the rotating element. The areas between the recesses can be formed, for example, by radial spokes of the rotating element. Such a design is found, for example, in typical pulleys of previously known speed limiters. The openings primarily serve to reduce the moment of inertia. In a safety device according to the disclosure, they can advantageously also define the first or second optical features. An optical path from the optical transmitter to the optical receiver typically runs parallel or substantially parallel to the axis of rotation.
[0029] In an alternative embodiment, the recesses distributed around the circumference of the rotating element extend in a radial direction. In such an embodiment, the optical path from the optical transmitter to the optical receiver typically also runs radially or substantially radially.
[0030] In a configuration of the rotating element with recesses as described, the optical transmitter and the optical receiver can be arranged, in particular, on opposite sides of the recesses and aligned with each other with their optical axes. In a configuration of the light barrier as a one-way light barrier, the recesses define the first optical features. The optical path from the optical transmitter to the optical receiver is continuous if it passes through one of the recesses, so that a light beam emanating from the optical transmitter reaches the optical receiver. In the area of the second optical features, however, the light beam is interrupted. The area of the second optical features is advantageously frosted or light-absorbing. 2021P00321WÖ
[0031] - 7 -
[0032] Alternatively, the light barrier can be a reflective light barrier, wherein the optical transmitter and the optical receiver are arranged side by side in a known manner and have parallel or nearly parallel optical axes. In such a configuration, a surface opposite the light barrier, onto which a light beam emitted by the optical transmitter can strike, can advantageously be frosted or absorbing, while the rotating element in the area between the recesses is designed to be reflective, so that the light beam is reflected from the optical transmitter to the optical receiver. In such a configuration, the recesses define the second optical features.A reverse arrangement is also possible, in which a reflective reflector is provided opposite the light barrier, which reflects light received through a recess, while the areas between the recesses, such as spokes, are light-absorbing or matte.
[0033] In an alternative embodiment, the optical features do not include any openings, but are formed by a sequence of alternating highly reflective and weakly reflective, or advantageously non-reflective or absorbing, areas. In such a configuration, the light barrier is advantageously a one-way light barrier.
[0034] In one embodiment, the rotating element comprises a pulley designed to be driven by a limiter rope that runs around the pulley. The limiter rope is an endless rope running parallel to the travel path in the elevator shaft, which is guided over the pulley and a deflection pulley. The deflection pulley is located in a lower section of the elevator shaft or in the pit.
[0035] In one embodiment, the safety device comprises an elevator control with an electrical safety circuit, wherein the elevator control is designed such that, in the event of an interruption of the electrical safety circuit, an elevator drive is de-energized and an elevator brake is activated.
[0036] In one embodiment, the safety device further comprises a service control unit designed for arrangement on the roof of a car of an elevator system, wherein the Auf-2021P00321WÖ
[0037] - 8 -train control is designed to control the elevator system in a normal operating mode and a service operating mode, wherein movement of the car in the service operating mode can be controlled via the service control unit, wherein the elevator control is designed to activate the speed monitor for operation in the service operating mode and to deactivate it for operation in the normal operating mode.
[0038] In one embodiment, the car and the rotating element are coupled by a limiter rope. The limiter rope is driven at the speed of the car.
[0039] In one embodiment, the elevator system comprises a safety gear mounted on the car, wherein the safety gear is coupled to the speed limiter, in particular mechanically coupled, such that the safety gear is activated by the speed limiter and immobilizes the car when the car speed reaches or exceeds a predetermined overspeed, where the overspeed is greater than the car's limit speed. The speed limiter typically comprises a blocking device operating in a known manner according to the pendulum or centrifugal force principle, which blocks the rotating element at a rotational speed corresponding to the overspeed. The locking of the rotating element triggers the safety gear. The coupling of the safety gear and the speed limiter, in particular the rotating element, can advantageously be effected by means of the limiter rope.Such a design with speed limiter, safety device and limiter cable is known as such from the prior art.
[0040] The safety gear is rigidly mounted to the car, typically a safety frame of the car, and can form a structural component of the car. When the car moves, the coupling of the limiter rope to the safety gear causes a corresponding movement of the limiter rope, thus driving the rotating device, in particular the pulley. The coupling of the limiter rope to the safety gear is advantageously rigid, i.e., the limiter rope is connected to the safety gear.
[0041] In one embodiment, the cutoff frequency corresponds to a car cutoff speed, wherein the car cutoff speed is less than a maximum car speed during normal operation of the elevator system. The car cutoff speed can, in particular, be 0.75 m / s. 2021P00321WÖ
[0042] - 9 -
[0043] In one embodiment, the elevator system comprises a service control unit arranged on the car roof, wherein the elevator system can be controlled in a normal operating mode and a service operating mode, wherein car movement in service operating mode can be controlled via the service control unit, and wherein the elevator control system is designed to activate the speed monitor for operation in service mode and deactivate it for operation in normal operating mode. With such a configuration, the speed monitor is typically not used in normal operation of the elevator system, since the regulation and limitation of the car speed by means of the elevator control system ensures a high level of safety for the persons inside the car.
[0044] In one embodiment, the method for creating an elevator system is a retrofit method for a pre-existing elevator system, wherein the speed limiter is a component of the pre-existing elevator system. In this case, to implement an elevator system according to the disclosure, only the speed monitor, in particular the light barrier, needs to be installed and the connection to the elevator control system established. In this way, the safety of older or generally pre-existing elevator systems can also be increased.
[0045] The following are examples of implementation explained in more detail with reference to the figures. They show:
[0046] Fig. 1 shows a lift installation according to the disclosure in a schematic side view and functional side view;
[0047] Fig. 2 shows a safety device as disclosed in a schematic frontal view;
[0048] Fig. 3 shows a schematic cross-sectional view corresponding to Fig. 2;
[0049] Fig. 4 shows another safety device according to the disclosure in a schematic cross-sectional view;
[0050] Fig. 5 shows a speed monitor as disclosed, together with an elevator control system, in a schematic functional view.
[0051] Reference is first made to Figure 1, which depicts a lift system 1 according to the disclosure in a highly schematic side view. The lift system 1 can be 2021P00321WÖ
[0052] - 10 - can be installed either as a new system in the form shown or by retrofitting an existing elevator system. Apart from aspects that will be specifically addressed below and / or above, elevator system 1 basically corresponds to an elevator system known from the prior art.
[0053] The elevator system 1 comprises a car 2 designed for the vertical transport of a load L consisting of persons and / or goods within its interior. For this purpose, the car 2 can be moved or shifted vertically in an elevator shaft 6 between two or more floors that are not separately referenced, guided by one or more guide rails 7 mounted in the elevator shaft 6. In normal operation, the elevator system is controlled by a car operation panel (COP) 11 located in the car 2 and / or by landing operation panels (LOPs) 12 located on the floors outside the elevator shaft 6.
[0054] In the embodiment shown, the elevator system 1 further comprises a counterweight 3, which can be displaced in the elevator shaft 6 in the opposite direction to the car 2. For displacing the car 2 and the counterweight 3, the elevator system 1 includes an elevator drive 5 with an electric machine 5.1 and a traction sheave 5.2. The traction sheave 5.2 is rotationally fixed to a rotor of the electric machine 5.1 and / or is integrally formed with it. The car 2 and the counterweight 3 are coupled via a flexible traction element 4, which is formed by one or typically several rope- and / or belt-like elements. Kinematically, the traction element 4 is guided between the car 2 and the counterweight 3 via the traction sheave 5.2 and coupled to it. Under the influence of a force applied by the electric machine 5.1 and transmitted via the traction sheave 5.2, the car 2 and the counterweight 3 are displaced.The moment 2 transferred to the traction means 4 and the additional force of gravity allows the elevator car 2 to be moved upwards and downwards in the elevator shaft 6, with a simultaneous counter-movement of the counterweight 3.
[0055] Furthermore, an elevator brake 8 is provided, which is designed to stop the car 2 and hold it immobile in position. For this purpose, the elevator brake 8 can, for example, be implemented as a machine brake and act on the rotor of the electric machine 5.1 and / or the traction sheave 5.2. Alternatively or additionally, an elevator brake can be arranged on the car 2. Other configurations are possible. The elevator brake 8 is advantageous 2021P00321WÖ
[0056] - 11 - a passively closing brake with, for example, an electromagnetic or hydraulic drive. Without a continuous power supply, the elevator brake 8 is passively activated or closed, for example, by springs. During operation of the elevator system 1, the elevator brake 8 is always activated when no movement of the car 2 is desired, for example, when stopped at floors, when the elevator system is at rest, or during work on the elevator system 1 where no movement of the car 2 is desired.
[0057] The elevator drive 5, the elevator brake 8, and the elevator system 1 as a whole are controlled by an elevator control unit 9. This unit can optionally be fully or partially integrated into other components of the elevator system 1. For example, at least part of the elevator control unit 9 can be located in or on the car 2 and / or on the elevator drive 5. A functional component of the elevator control unit 9 is a safety circuit 9.1, which, in a known manner, comprises a number of electrical contacts (not shown individually). For the car 2 to move, the safety circuit 9.1 must be closed, i.e., form a closed electrical path. Among other things, the power supply to the electric motor 5.1 and the elevator brake requires a closed safety circuit. If the safety circuit is interrupted, these components are disconnected from the power supply and de-energized.
[0058] The elevator system 1 further comprises, in a generally known manner, a speed limiter 14, which is mechanically coupled to and interacts with a safety gear 19. The speed limiter 14 comprises a rotating element 15, which is implemented, for example, as a pulley, and a locking device 16, typically operating on the centrifugal or pendulum principle. The speed limiter 14 is typically arranged above the travel path of the car 2, for example, together with the elevator drive 5.1 in a shaft head or separate machine room. The safety gear 19 is arranged on the car 2. A limiter rope 17, designed as an endless rope, is guided over the rotating element 14 and a deflection pulley 18 located at the bottom of the elevator shaft 6, for example, in a pit. Furthermore, the limiter rope 17 is coupled to the safety gear 17.When the car 2 is displaced at a car speed v, the limiter rope 17 is driven, which in turn drives the rotating element 15, whereby the rotational speed w of the rotating element 15 is proportional to the car speed-2021P00321WÖ.
[0059] - 12 -speed v is. If, in the event of a fault, the car speed v in the elevator shaft 6 exceeds a predetermined overspeed and the rotating element 15 has a correspondingly high rotational speed, the blocking device 16 is triggered and blocks the rotating element 15. The resulting jerk of the limiter rope 17 is transmitted to the safety gear 19 and activates it. The safety gear 19, in turn, interacts with the guide rail(s) 7 and securely locks the car 2 independently of the elevator brake 8. At the same time, a safety circuit 9.1 is interrupted.
[0060] Furthermore, the elevator system 1 includes a service control unit 10 located on the car roof 2.1. Using the service control unit 10, an appropriately authorized and qualified person, such as a service technician, located on the car roof 2.1, can manually move the car in service mode in the elevator shaft 6 in both upward and downward directions. This generally requires the simultaneous activation of two operating elements, for example, pushbuttons, on the service control unit 10. Releasing one button immediately interrupts the safety circuit 9.1.
[0061] Due to its positioning on the car roof 2.1, and thus outside the protected car interior, the person in question is at an increased risk of accidents and injuries. Therefore, it must be ensured that any movement of the car 2 only occurs at a reduced speed compared to normal operation. This reduced speed is also designed to allow the person to react in the event of a hazardous situation, for example, by making an evasive movement or releasing the controls on the service control unit 10.
[0062] In principle, the elevator car speed v is regulated and monitored in a known manner by the elevator control unit 9. In an elevator system according to the disclosure, a safety device 13, preferably active only in service mode, is provided to further increase safety, as described in more detail below. The safety device 13 comprises the rotating element 15 of the speed limiter and a speed monitor 20. The safety device 13 monitors the elevator car speed v independently of the elevator control unit 9.
[0063] Reference is also made below to Figure 2 and Figure 3, which represent an execution of 2021P00321WÖ
[0064] Figure 13 shows the embodiment of a safety device 13 as disclosed in corresponding schematic frontal and cross-sectional views. In the embodiment shown, the rotating element 15, designed as a pulley, comprises an outer ring 15.3, which is arranged concentrically to a hub 15.4. The center of the hub 15.4 is formed by a rotation axis R. The outer ring 15.3 includes a limiter cable coupling structure (not shown), e.g., in the form of a circumferential groove, for coupling with the limiter cable 17 according to Figure 1. Furthermore, the rotating element 15 comprises a number of spokes, preferably arranged uniformly around the circumference, which extend between the hub 15.4 and the outer ring 15.3 and connect them. Recesses in the form of axially through openings are located between the spokes.These are typically provided in known designs of pulleys in speed limiters 13 to save material and / or reduce the moment of inertia. In an arrangement according to the disclosure, the recesses 15.1 can represent or define first optical features 15.1' and the spokes 15.2 can represent or define second optical features 15.2'.
[0065] Furthermore, an optical transmitter 20.1 and an optical receiver 20.2 are provided, which together form a one-way light barrier. The optical transmitter 20.1 and the optical receiver 20.2 are arranged at the same radial distance from the axis of rotation R and axially offset from each other. The optical transmitter 20.1 and optical receiver 20.2 are preferably aligned towards each other, with their optical axes advantageously being parallel to the axis of rotation R. As can be seen in Figure 3, the optical transmitter 20.1 and the optical receiver 20.2 are arranged such that the rotating element 15 runs axially between them. When the rotating element 15 rotates, a light beam B from the optical transmitter 20.1 to the optical receiver 20.2 is interrupted, or rather, there is no continuous optical path if a spoke is located between the optical transmitter 20.1 and the optical receiver 20.2. If there is a spoke between the optical transmitter 20.1 and the optical receiver 20.2, the optical transmitter 20.1 is interrupted.Since there is a recess between optical transmitter 20.1 and optical receiver 20.2, an optical path between optical transmitter 20.1 and optical receiver 20.2 is continuous, and the light beam B emanating from optical transmitter 20.1 is detected by optical receiver 20.2. Thus, a receiver output signal of optical receiver 20.2 is modulated according to the rotational speed of the rotating element.
[0066] An arrangement according to Figure 2 and Figure 3 is particularly suitable for retrofitting an existing elevator system, since a speed limiter 14 with a corresponding 2021P00321WÖ
[0067] - 14 - Pulley as rotational element 15 is typically already present.
[0068] Reference is also made below to Figure 4, which shows a further embodiment of a safety device 13 according to the disclosure in a schematic cross-sectional view similar to Figure 3. In the arrangement according to Figure 4, the optical transmitter 20.1 and the optical receiver 20.2 are also aligned with each other, but have optical axes radially aligned with respect to the axis of rotation R, and a light beam B emanating from the optical transmitter 20.1 extends radially. The recesses 15.1, which define the first optical features 15.1', extend radially and can, for example, be realized by bores.
[0069] Other arrangements and variants are also possible. For example, the optical transmitter 20.1 and the optical receiver 20.2 can form a reflective light barrier instead of a one-way light barrier and be arranged with parallel optical axes on one side of the recesses 15.1. An optically reflective element can be arranged on the side of the rotating element 15 opposite the light barrier, and the spokes 15.2 can be optically frosted or absorbing. In another variant with a reflective light barrier, an optically frosted or absorbing element is arranged on the side of the rotating element 15 opposite the light barrier, while the spokes 15.2 are optically reflective. In this case, the roles of the first optical features 15.1' and the second optical features 15.2' are reversed. Furthermore, when using a reflective light barrier, it is possible to reverse the roles of the first optical features 15.1' and the second optical features 15.2'.2' by providing alternating reflective and absorbing or matte areas on a surface of the rotating element 15. Furthermore, to realize the first optical features 15.1' and second optical features 15.2', for example, axially projecting wings distributed around the circumference of the rotating element can be provided in an alternative embodiment based on Figure 4, or axially projecting wings can be provided in an alternative embodiment based on Figures 2 and 3.
[0070] Reference is also made below to Figure 5, which shows a schematic functional view of a claimed speed monitor 20. The optical transmitter 20.1 serves as a light source and can, in principle, be implemented in various ways. It can be, in particular, a light-emitting diode (LED) emitting in the visible and / or infrared (IR) range, but also, for example, a laser light source or an incandescent lamp. 2021P00321WÖ
[0071] - 15 - The optical receiver 20.2 comprises an optoelectronic element sensitive in the relevant spectral range, in particular a photodiode or a phototransistor, or also a photocell. The optical transmitter and / or the optical receiver may include further optical elements such as apertures, lenses and / or deflection systems such as mirrors and / or prisms and / or optical filters.
[0072] The optical receiver 20.2 provides a binary modulated receiver output signal, which is transmitted to and evaluated by an evaluation unit 20.3. A signal frequency f of the receiver output signal is proportional to the rotational speed w of the rotating element 15 and thus to the car speed v. Furthermore, the signal frequency f is proportional to the number of consecutive first optical features 15.1' and second optical features 15.2' determined by the design, as these determine the light-dark transitions registered by the optical receiver 20.2 for each revolution of the rotating element 15. In the evaluation unit 20.3, the signal frequency f is continuously adjusted with a stored cutoff frequency f when the car 2 is moving in service mode. LThe cutoff frequency fi corresponds to a car cutoff speed. The car cutoff speed is a speed of the car 2 that must not be exceeded in service mode and which is below the overspeed at which the safety gear 19 would be activated. The car cutoff speed can be, for example, 0.75 m / s. If the signal frequency fi reaches or exceeds the cutoff frequency fi, the following occurs: L , the safety circuit 9.1 is interrupted via a stop signal S.
[0073] The aforementioned design of the safety device 13 and, in particular, the speed monitor 20 can be modified in various ways. For example, the optical transmitter 20.1 can be controlled to emit a light beam with a temporally variable or modulated intensity. In this case, the light intensity registered by the optical receiver 202.2 is modulated not only with the signal frequency f, but also, advantageously, with the significantly higher frequency of the optical transmitter 20.1. The receiver output signal can be filtered accordingly, for example, with a bandpass filter. In this way, the sensitivity to ambient light can be reduced. Furthermore, the cutoff frequency f L be variable and, for example, be predefined differently by the elevator control system for different operating situations or modes. 2021P00321WÖ
[0074] - 16 - It is noted that the frequency f of the receiver output signal is determined by the number of first optical features 15.1' and second optical features 15.2'. The duty cycle, i.e., the ratio of the durations of the two levels of the receiver output signal, depends, on the other hand, on the design and arrangement of the first optical features 15.1' and second optical features 15.2'. For an arrangement according to Figures 2 and 3, the duty cycle is 1:1 if the angular ranges detected by the light barrier are identical, or if the angular range of a recess 15.1 is equal to the angular range of a spoke 15.2. In one embodiment, the duty cycle is evaluated and compared with an expected duty cycle. This allows the interference immunity to be increased.
Claims
2021P00321WÖ - 17 - Patent claims 1. Safety device (13) for a lift system (1), the safety device (13) comprising: - a speed limiter (14), wherein the speed limiter (14) is designed such that a rotating element (15) of the speed limiter (14) is driven by the car (2) during a travel movement along a travel path and rotates at a rotational speed (w), wherein the rotational speed (w) is proportional to a car speed (v), wherein the rotating element (15) has circumferentially alternating first optical features (15.1') and second optical features (15.2'), wherein the first (15.1') and second (15.2') optical features differ with respect to their optical transmittance and / or reflectance; - a speed monitor (20), the speed monitor (20) comprising a light barrier and an evaluation unit (20.3), wherein the light barrier comprises an optical transmitter (20.1) and an optical receiver (20.2), wherein the optical transmitter (20.1) and the optical receiver (20.2) are arranged such that a light flux from the optical transmitter (20.1) to the optical receiver (20.2) is periodically modulated by the first (15.1') and second (15.2') optical features when the rotating element (15) is rotated. and wherein the receiver (20.2) is designed to provide a receiver output signal that changes depending on a received light intensity; wherein the evaluation unit (20.3) is designed to compare a signal frequency (f) of the receiver output signal (S) with a cutoff frequency (fi) and to generate a speed stop signal when the signal frequency reaches and / or exceeds the cutoff frequency (f), wherein at least the speed limiter (14), the optical transmitter (20.1) and the optical receiver (20.2) are designed for fixed installation in the elevator system (1).
2. Safety device (13) according to claim 1, wherein the first optical features (15.1') allow the light flow from the optical transmitter (20.1) to the optical receiver (20.2) and the second optical features (15.2') prevent the light flow from the optical transmitter (20.1) to the optical receiver (20.2). 2021P00321WÖ - 18 - 3. Safety device (13) according to one of the preceding claims, wherein the rotating element (15) has recesses (15.1) wherein the first optical features (15.1') or the second optical features (15.2') are defined by the recesses.
4. Safety device (13) according to one of the preceding claims, wherein the light barrier is a one-way light barrier, wherein the optical transmitter (20.1) and the optical receiver (20.2) are arranged on a common axis, in particular parallel to an axis of rotation (R) of the rotating element (15), on different sides of the rotating element (15).
5. Safety device (13) according to one of the preceding claims, wherein the rotating element (15) comprises a pulley designed to be driven by a limiter rope (17) guided around the pulley.
6. Lifting system (1), comprising: - a car (2); - an elevator drive (5); - a traction means (4) wherein the car (2) and the elevator drive (5) are coupled via the traction means (4) in such a way that the car can be moved vertically along a travel path via the elevator drive (5); - an elevator brake (8), wherein the elevator brake (8) is designed to stop any movement of the car (2) when activated and to hold the car in position; - an elevator control (9) with an electrical safety circuit (9.1), wherein the elevator control is designed such that in the event of an interruption of the electrical safety circuit (9.1) the elevator drive (5) is de-energized and the elevator brake (8) is activated; - a safety device (13) according to one of the preceding claims, wherein the evaluation unit (20.3) is coupled to the safety circuit (9.1) such that the speed stop signal causes an interruption of the safety circuit (9.1).
7. Lift system (1) according to claim 6, wherein the limiting frequency (fi ) corresponds to a car limiting speed, wherein the car limiting speed is less than a 2021P00321WÖ - 19 - maximum car speed in normal operation of the lift system (1), wherein the car limit speed is in particular 0.75m / s.
8. Elevator system (1) according to claim 6 or claim 7, wherein the elevator system (1) comprises a service control unit (10) arranged on a car roof (2.1), wherein the elevator system (1) is controllable in a normal operating mode and a service operating mode, wherein movement of the car in the service operating mode is controllable via the service control unit (10), wherein the elevator control (9) is designed to activate the speed monitor (20) for operation in the service operating mode and to deactivate it for operation in the normal operating mode.
9. Elevator system (1) according to one of claims 6 to 8, further comprising a safety gear (19) mounted on the car (2), wherein the safety gear (19) is coupled to the speed limiter (14) in such a way, in particular mechanically coupled, that the safety gear (19) is activated by the speed limiter (14) and stops the car (2) when the car speed (v) reaches or exceeds a predetermined overspeed, wherein the overspeed is greater than the car limit speed.
10. Lifting system (1) according to one of claims 6 to 9, wherein the car (2) and the rotating element (15) are coupled by a limiter rope (17).
11. Method for constructing an elevator system (1) according to any one of claims 6 to 10, the method comprising: Mounting a speed monitor (20) such that a speed limiter (14) of the elevator system (1) and the speed monitor (20) form a safety device according to one of claims 1 to 5, Coupling, in particular a wired coupling, of the evaluation unit (20.3) with the elevator control (9), so that during operation the speed stop signal is transmitted from the evaluation unit (20.3) to the elevator control (9).
12. The method of claim 11, wherein the method is a retrofit method for a pre-existing elevator system (1), wherein the speed limiter (14) is a component of the pre-existing elevator system (1). 2021P00321WÖ - 20 - 13. Use of a safety device (13) according to one of claims 1 to 5 for speed monitoring during the operation of an elevator system, in particular an elevator system (1) according to one of claims 6 to 10 in a service operating mode, wherein a continuous comparison of the signal frequency (f) with the cutoff frequency (fi ) and interruption of the safety circuit is carried out when the signal frequency (f) exceeds the cutoff frequency (fi.).