Method for monitoring a rotational movement of a toothed wheel in the drive of an escalator or moving walkway

Abstract

The invention relates to a method for monitoring a rotary movement of a gear (13) in the drive (3) of an escalator (1), comprising: receiving a sensor signal (21), which was generated using a sensor (15) for scanning teeth (17, 17a, 17b) of the gear (13), in a signal processing device (19); detecting pulses (25) by scanning the sensor signal (21), the pulses (25) being counted by assigning a count value (37) to each pulse (25), each pulse (25) also being assigned a time value (39) which indicates a time interval between the pulse (25) and the next pulse (25); carrying out the following steps for each detected pulse (25): selecting a reference time value (41) by comparing the count value (37) assigned to the detected pulse (25) with a list (43) which assigns reference time values (41) to possible count values (37); determining a deviation of the time value (39) assigned to the detected pulse (25) from the selected reference time value (41); on the basis of the deviation, detecting whether the gear (13) is rotating at a desired speed.

Description

[0001] The present invention relates to a method for monitoring the rotary motion of a gear in the drive of an escalator. Furthermore, the invention relates to a signal processing device, a computer program and a computer-readable medium for carrying out the method, as well as a sensor device and an escalator.

[0002] Monitoring the rotational speed and / or direction of rotation of a gear in an escalator, such as a sprocket in a chain drive for powering a step or pallet conveyor and / or a handrail, can be achieved, for example, using two inductive sensors positioned opposite the gear teeth at different scanning points. The number of pulses available per revolution for detecting the respective motion parameter is limited by the number of sensors. While using more than two sensors increases the number of pulses per revolution, i.e., the resolution of the resulting sensor signal, it can also introduce signal irregularities that, despite the increased resolution, may lead to undesirable measurement inaccuracies. US 4,664,247 A, EP 1,850,087 A1, and US 2012 / 283870 A1 disclose methods and sensor devices according to the prior art.

[0003] Therefore, there may be a need for a method that enables monitoring of the rotary motion of a gear in the drive of an escalator with increased accuracy and / or increased reliability, especially when more than two sensors are used to simultaneously scan the toothing of the gear.

[0004] Furthermore, there may be a need for a suitable signal processing device, a suitable computer program, a suitable computer-readable medium, a suitable sensor device, and a suitable escalator. These needs can be met by the subject matter of the independent claims. Advantageous embodiments are set forth in the dependent claims, the following description, and the accompanying figures. A first aspect of the invention relates to a method for monitoring the rotary motion of a gear in the drive of an escalator.The method comprises the following steps: receiving a sensor signal, generated using at least one sensor for scanning the gear teeth, in a signal processing unit; detecting pulses by scanning the sensor signal, counting the pulses by assigning a count value to each pulse, and further assigning a time value to each pulse indicating the time interval between the pulse and the next pulse; performing the following steps for each detected pulse: selecting a reference time value by comparing the count value assigned to the detected pulse with a list that assigns reference time values ​​to possible count values; determining a deviation of the time value assigned to the detected pulse from the selected reference time value; and determining, based on the deviation, whether the gear is rotating at a desired speed.

[0005] The process can be computer-implemented and executed automatically by a processor, for example, a signal processing unit of the escalator.

[0006] The method makes it possible to compensate for inconsistencies in the sensor signal, for example due to inaccuracies of the gear and / or the sensor and / or due to the so-called polygon effect in a chain drive.

[0007] More precisely, the method allows for the selection of a separate threshold from several possible thresholds for each detected pulse, i.e., for each tooth of the gear for which a pulse was generated. In this way, geometric irregularities of the gear and / or other inherent inaccuracies, such as in the orientation of an active surface of the sensor (sensor detection area) to the gear and / or to each other (e.g., due to wear and / or temperature fluctuations), can be taken into account during monitoring. This significantly increases the accuracy and / or reliability of the monitoring compared to methods that use the same threshold for all sections of the gear.

[0008] If multiple sensors are used to scan the gear teeth, the previously described individual irregularities can result in a sensor signal with regularly alternating long and short periods. Such a long-short pattern can significantly impair the measurement of the gear's rotational speed, especially if the periods of the long-short pattern are compared to the same reference period, regardless of their individual lengths. This method effectively compensates for such irregularities.

[0009] For example, it can be detected that the gear is rotating too fast if the time value is smaller than the selected reference time value, and / or rotating too slowly if the time value is larger than the selected reference time value.

[0010] In this case, an additional step can be taken to generate a control command to stop the escalator. Such a control command typically causes a safety circuit of the escalator to be interrupted.

[0011] It is advantageous to sample the sensor signal for rising edges, where each pulse begins. In this case, "time value" can be understood as the time interval between two adjacent rising edges in the sensor signal. However, sampling for falling edges, where each pulse ends, or sampling for both rising and falling edges is also possible.

[0012] The gear could, for example, be a sprocket from the escalator's chain drive. The chain drive might be designed to power a step or pallet conveyor and / or a handrail of the escalator. In this case, the sprocket's teeth, when the escalator is in operation, can be connected to a drive pinion of the escalator via a drive chain. In other words, the individual teeth of the sprocket can be used as a physical measure for detecting the rotational movement. This eliminates the need for an additional physical measure, thus reducing the escalator's manufacturing costs. Alternatively, a gear could be used as an additional measuring gear that rotates during escalator operation but does not itself transmit any driving forces.

[0013] For ease of reading, the terms "escalator and steps" are used exclusively in this description. Naturally, the invention can be used equally with moving walkways using pallets, and therefore, the claims also encompass its implementation in moving walkways.

[0014] A second aspect of the invention relates to a signal processing device with a processor configured to perform the method described above and below. The signal processing device may comprise hardware and / or software modules. In addition to the processor, the signal processing device may include memory and a data communication interface for wireless and / or wired data communication with peripheral devices. The signal processing device may, for example, be part of an escalator control system. However, it may also be designed as a unit physically separate from the escalator. Naturally, it is also possible for the signal processing device to be implemented in a data cloud (cloud computing) and to use decentralized hardware of the internet.

[0015] It should be noted that features of the procedure as described above and below may also be features of the signal processing device (and vice versa).

[0016] A third aspect of the invention relates to a sensor device. The sensor device comprises at least four sensors for scanning the teeth of a gear in the drive of an escalator at at least four scanning points, each sensor having an active surface and being mountable such that the active surface of the teeth faces the respective scanning point. Each of these sensors is designed to emit an electrical pulse each time one of the teeth of the gear passes the respective active surface.The sensor device further comprises at least two outputs for connecting the sensor device to at least two inputs of a signal processing device (for example, the signal processing device described above and below), wherein a first of the outputs can be connected to a first of the inputs via a first signal line, wherein a second of the outputs can be connected to a second of the inputs via a second signal line (separate from the first signal line), wherein at least two of the sensors are connected to the first output to provide a first sensor signal, and wherein at least two more of the sensors are connected to the second output to provide a second sensor signal.

[0017] This allows the use of a simpler and correspondingly cheaper signal processing device compared to sensor devices where the output of each sensor is connected to a separate input of the signal processing device.

[0018] Furthermore, such a sensor system enables significantly more accurate and / or reliable measurements compared to systems with fewer than four sensors, for example, with only two or even just one sensor. It also makes it possible to verify the correct functioning of the escalator by comparing the signals from both measurement channels.

[0019] The term "sensor" can refer, for example, to an inductive sensor, a Hall sensor, an optical sensor, or a combination of at least two of these examples, as used above and below.

[0020] The sensors in the sensor system can therefore be of the same type or of different types. If the sensors are inductive, they can, for example, differ in their oscillation frequency. This prevents the sensors from interfering with each other during operation. However, the inductive sensors can also have the same oscillation frequency.

[0021] Preferably, the sensors can be mounted in such a way that the active surfaces have different positions relative to a circumferential direction of the gear.

[0022] The sensors can each be mounted using a special bracket. Such a bracket can be designed to allow precise alignment of the active surface of the respective sensor in three spatial directions, i.e., in the x, y, and z directions, relative to the gear teeth.

[0023] It should be noted that features of the procedure as described above and below may also be features of the sensor device (and vice versa).

[0024] For example, the procedure described above and below may further include: generating the first sensor signal and / or the second sensor signal by the sensor device described above and below.

[0025] In other words, the first sensor signal provided at the first output of the sensor device and / or the second sensor signal provided at the second output of the sensor device may be suitable to be processed using the method described above and below.

[0026] A fourth aspect of the invention relates to an escalator. The escalator comprises: a drive with a gear; at least one sensor for scanning a tooth of the gear at at least one scanning point, wherein the sensor has an active surface and is mounted such that the active surface is opposite the tooth at the scanning point, wherein the sensor is configured to emit an electrical pulse each time one of the teeth of the tooth passes the active surface; and the signal processing device described above and below.

[0027] As an alternative to at least one sensor, the escalator can include the sensor device described above and below, wherein each sensor of the sensor device is mounted in such a way that the active surface of the respective sensor is opposite the toothing at the respective scanning point.

[0028] It should be noted that features of the procedure as described above and below may also be features of the escalator (and vice versa).

[0029] Further aspects of the invention relate to a computer program and a computer-readable medium on which the computer program is stored.

[0030] The computer program includes instructions that, when the computer program is executed by the processor, cause a processor of a signal processing device to perform the procedure described above and below.

[0031] The computer-readable medium can be a volatile or non-volatile data storage device. For example, the computer-readable medium can be a hard drive, a USB storage device ( universal serial bus ), a RAM ( random-access memory ), a ROM ( read-only memory ), a PROM ( programmable read-only memory ), an EPROM ( erasable programmable read-only memory ), an EEPROM ( electrically erasable programmable read-only memory), It could be flash memory or a combination of at least two of these examples. The computer-readable medium could also be a data communication network that allows the downloading of program code (e.g., via the internet), or a cloud.

[0032] It should be noted that features of the procedure as described above and below may also be features of the computer program and / or the computer-readable medium (and vice versa).

[0033] Embodiments of the invention can be considered to be based on the ideas and findings described below. These embodiments are not to be understood as limiting the scope of the invention.

[0034] According to one embodiment, the counting of pulses can be restarted if the count value of the last detected pulse matches a stop value that specifies a number of pulses within a pulse pattern that repeats in the sensor signal.

[0035] The counting process can be restarted by resetting a counter to a starting value, such as 0 or 1. The counting then continues from this starting value, with the counter incrementing by, for example, 1 with each detected pulse, until the starting value is reached again. The counting can be performed continuously while the escalator is in operation.

[0036] In other words, the set of possible count values ​​that can be assigned to the detected pulses is not indeterminate, but limited to specific count values. For example, the set of possible count values ​​can include values ​​for counting up to four (e.g., "0, 1, 2, 3" or "1, 2, 3, 4") if the repeating pulse pattern consists of four consecutive pulses.

[0037] The repeating pulse pattern can be a known pulse pattern with a known number of pulses. This known pulse pattern could, for example, result from the configuration of a chain drive in the escalator that includes the gear. It is also possible that the pulse pattern was determined in trials or in one or more separate learning runs before or during normal escalator operation.

[0038] In the simplest case, the stop value can be 2. In this case, the repeating pulse pattern comprises exactly two consecutive pulses. However, the stop value can also be significantly larger than 2. For example, the stop value can be equal to the number of teeth on the gear (or an integer multiple thereof) and / or the number of links in the drive chain (or an integer multiple thereof). In other words, the stop value can be equal to the number of pulses generated by the sensor(s) during one or more complete revolutions of the gear and / or drive chain in the same direction.

[0039] It is possible that the pulse pattern of the escalator may change during operation, for example due to temperature fluctuations or increasing wear. Therefore, it is advisable to automatically scan the sensor signal for recurring pulse patterns and determine a corresponding stop value from this.

[0040] Therefore, according to one embodiment, the method can further include a step in which a repeating pulse pattern is detected by scanning the sensor signal. In this case, the pulses can be detected taking into account the detected pulse pattern. This enables automatic detection of repeating pulse patterns in the sensor signal.

[0041] The sensor signal can be sampled for rising and / or falling edges. Such detection can be performed, for example, every time the escalator starts and / or during normal operation (e.g., at regular intervals and / or when specific events are detected). Detection can occur, for instance, during a learning run of the escalator, in which the gear is rotated 360 degrees or an integer multiple of 360 degrees in the same direction. Alternatively, the gear can also be rotated by less than 360 degrees during the learning run.

[0042] It is possible to detect multiple repeating pulse patterns by sampling the sensor signal. The detected pulse patterns can differ from each other in at least one of the following parameters: the number of pulses, the time intervals between pulses, or the total duration. Accordingly, a separate list of count values ​​and reference time values ​​can be generated for each detected pulse pattern. One of these lists can then be automatically selected to evaluate the sensor signal, for example, depending on the current operating conditions of the escalator. The system can therefore switch between the different lists several times during escalator operation. It is also conceivable that the sensor signal can be evaluated simultaneously using several such lists. This creates a degree of redundancy, which improves the reliability of the process.

[0043] According to one embodiment, the stop value can specify a number of pulses within the detected pulse pattern. In other words, when the pulse pattern is detected, it can be determined, among other things, how many pulses the pulse pattern comprises and a corresponding stop value can be set (for example, a stop value of "4" for a count from 1 to 4 for four pulses, or a stop value of "3" for a count from 0 to 3). This allows for an automatic update of the stop value when a new pulse pattern is detected, for example, as a result of temperature fluctuations and / or increasing wear.

[0044] According to one embodiment, pulse pattern recognition can include: counting the pulses within the pulse pattern by assigning a count value to each pulse; determining a time value for each pulse within the pulse pattern, the time value indicating the time interval between the pulse and the next pulse. The method can further include: determining a reference time value for each count value assigned to a pulse during pulse pattern recognition by multiplying the time value of the respective pulse by a factor; and storing the reference time values ​​together with the respective count values ​​in the list.

[0045] In other words, a set of possible count values, which are later used to count the pulses, and their associated reference time values ​​can be determined from the sensor signal. For example, if the count values ​​"1, 2, 3, 4" (or "0, 1, 2, 3") were assigned sequentially when the pulse pattern was detected, the system will count up to the count value 4 (or 3) when the pulses are detected, before starting again from 1 (or 0). In other words, each count ends after the fourth pulse; that is, the stop value is 4 (or 3) and corresponds to the number of pulses within the detected pulse sequence. A specific reference time value is stored in the list for each of the aforementioned count values. The aforementioned steps can be performed during a learning phase outside of normal escalator operation and / or in parallel with normal escalator operation.

[0046] This allows for an automatic update of the reference time values ​​when a new pulse pattern is detected, for example as a result of temperature fluctuations and / or increasing wear.

[0047] Furthermore, the detected impulse pattern can be used to identify properties of the respective chain drive of the escalator, for example to determine whether the escalator is equipped with the correct chain drive.

[0048] The factor can, for example, be between 0.80 and 0.95, preferably at 0.90.

[0049] According to one embodiment, the method may further include a step in which the plausibility of the detected pulse pattern is determined by comparing its total duration with a reference duration. The detected pulse pattern is retained if it is plausible and / or discarded if it is implausible.

[0050] For example, the sensor signal can be resampled in response to the discarding of the pulse pattern in order to detect a repeating pulse pattern.

[0051] The total duration of the detected pulse pattern can be measured and / or calculated. Preferably, the total duration is determined by adding the time values ​​of the pulses within the detected pulse pattern.

[0052] The reference duration can, for example, be a quotient of the distance traveled by the gear during the total duration of the detected pulse pattern (i.e., counting the pulses until the respective stop value is reached) and the desired speed of the gear, or be determined depending on this quotient.

[0053] For example, the detected pulse pattern may be classified as implausible if the total duration is outside a certain tolerance range (e.g. plus / minus 1%, plus / minus 5% or plus / minus 10%) around the reference duration.

[0054] According to one embodiment, the sensor signal can be generated using at least two sensors to scan the gear teeth at different sampling points, in particular by superimposing the output signals of the at least two sensors over the same period. In this way, the accuracy of the method can be significantly increased compared to versions using only one sensor. Preferably, the sensor signal is generated such that the pulses in the sensor signal do not overlap in time. This allows for an unambiguous determination of the number and length of the pulses.

[0055] According to one embodiment, the sensor signal (generated using at least two sensors) can be a first sensor signal, and a second sensor signal, generated using at least two further sensors, in particular by superimposing the output signals of the at least two further sensors over the same period, can be received in the signal processing device. Both sensor signals can be generated such that each pulse in the first sensor signal partially overlaps with a pulse in the second sensor signal. Accordingly, the method can further include: determining the current direction of rotation of the gear by evaluating the first sensor signal together with the second sensor signal and / or using the second sensor signal to detect whether the gear is rotating at the desired speed.

[0056] The direction of rotation can be determined, for example, by a characteristic sequence of rising and / or falling edges of pulses in a superposition of the two sensor signals over the same period, or, in other words, by a characteristic sequence of overlapping pulses of the two sensor signals.

[0057] If the current direction of rotation deviates from a desired direction of rotation, a control command to stop the escalator can be generated in an additional step.

[0058] When using the second sensor signal for speed monitoring, the second sensor signal can be processed in the same or a similar way as the (first) sensor signal. For example, the two sensor signals can be processed in parallel for this purpose, thus creating a degree of redundancy. This has the advantage that the speed monitoring still functions with sufficient accuracy even if one of the two sensor signals fails or is disrupted for any reason.

[0059] According to one embodiment, the sensors of the sensor device can be mounted such that the active surfaces have the same position with respect to an axial direction of the gear. For example, the active surfaces can be arranged one behind the other when viewed in the circumferential direction of the gear. Alternatively, the active surfaces can also partially overlap when viewed in the circumferential direction of the gear. Such a linear arrangement of the active surfaces can be advantageous for space reasons.

[0060] Alternatively, the sensors can be mounted in such a way that at least two of the active surfaces each have a first position and at least two further active surfaces each have a second position that differs from the first position with respect to an axial direction of the gear.

[0061] If the gear is a duplex gear with a first tooth and a second tooth whose teeth are aligned with the teeth of the first tooth in the axial direction of the gear, then, for example, the active surfaces of the first tooth located in the first position and the active surfaces of the second tooth located in the second position can be opposite each other.

[0062] It is possible that the sensors whose active surfaces are in the first position are connected to the first output of the sensor device, while the sensors whose active surfaces are in the second position are connected to the second output of the sensor device. Alternatively, the sensors whose active surfaces are in different positions with respect to the axial direction can be connected to the same output.

[0063] According to one embodiment, the first positions in the circumferential direction of the gear can be offset from each other by more than one whole tooth pitch (p) of the gear.

[0064] According to one embodiment, the second positions can be offset from each other in the circumferential direction of the gear by more than one whole tooth pitch (p) of the gear.

[0065] The respective offset can be, for example, at least 1.01p, at least 1.1p, or at least 1.5p. Additionally, the respective offset can be less than twice the whole tooth pitch, for example, at most 1.99p, at most 1.9p, or at most 1.6p. This ensures that the pulses from the respective sensors (which may, for example, be connected to the same output) do not overlap in time. This allows for an unambiguous determination of the number and length of the pulses.

[0066] According to one embodiment, the first positions in the circumferential direction of the gear can have the same distance from each other as the second positions.

[0067] According to one embodiment, each first position can be offset from one of the second positions in the circumferential direction of the gear by less than one full tooth pitch (p) of the gear, in particular by less than half a tooth pitch of the gear. The offset can be, for example, 0.99p or less, 0.9p or less, in particular 0.49p or less, or 0.4p or less. In tests, an offset between 1 mm and 5 mm, in particular 3 mm, proved to be particularly advantageous. This has the effect that the pulses of a sensor whose active surface is located in the first position partially overlap with the pulses of a sensor whose active surface is located in the second position, which is offset from the first position in this way. This enables, for example, the detection of the current direction of rotation of the gear (see also above).

[0068] By using such a pairwise arrangement of the active surfaces, some problems that occurred with the aforementioned linear arrangement could largely be avoided.

[0069] The following describes embodiments of the invention with reference to the accompanying drawings. Neither the description nor the drawings are to be understood as limiting the scope of the invention. Fig. 1 shows an escalator according to one embodiment of the invention. Fig. 2 shows a sensor device according to an embodiment of the invention. Fig. 3 shows a sensor device according to an alternative embodiment of the invention. Fig. 4 shows sections of sensor signals as they are processed in a method according to an embodiment of the invention.

[0070] The drawings are purely schematic and not to scale. If the same reference symbols are used in different drawings, these reference symbols denote identical or equivalent features.

[0071] Fig. 1 Figure 1 shows an escalator 1 with a chain drive 3 for driving a step 5 and a handrail 7 of the escalator 1. The chain drive 3 comprises a drive pinion 9, which is connected via a drive chain 11 to a sprocket 13. The sprocket 13 can be a main drive wheel, which is connected via a shaft to a first drive wheel for driving the step 5 and a second drive wheel for driving the handrail 7. The drive pinion 9 can be driven by an electric motor. A gearbox can be arranged between the drive pinion 9 and the electric motor to transmit rotary motion and torque.

[0072] Furthermore, the escalator 1 includes a sensor 15 for scanning a tooth 17 of the gear 13 at a scanning point 18 and a signal processing device 19 for processing a sensor signal 21 generated using the sensor 15. The sensor 15 can be, for example, an inductive sensor, a Hall sensor, an optical sensor, or a combination of at least two of these sensor types. The sensor 15 is arranged such that its active surface 23 is located opposite the tooth 17 at the scanning point 18 at a specific distance. Each time one of the teeth of the gear 17 passes the active surface 23, the sensor 15 generates an electrical pulse 25 (see Fig. 4 The sensor signal 21 can be an output signal of sensor 15. Alternatively, the sensor signal 21 can be based on the output signal.

[0073] As in Fig. 2 and Fig. 3 As shown, the escalator 1 can alternatively include a sensor device 27 with several sensors for scanning the gearing 17 at several scanning points 18, here with a first sensor 15a, a second sensor 15b, a third sensor 15c and a fourth sensor 15d ( Fig. 2 and Fig. 3 Each figure shows a toothed section of the gear 13 in a top view, with the head surfaces 28 of the individual teeth facing the plane of the drawing).

[0074] As in Fig. 2 As shown, the four sensors 15a, 15b, 15c, 15d can, for example, be mounted such that their active surfaces 23 face the same side of the gear teeth 17, here one of the side flanks of the gear teeth 17. The active surfaces 23 can have essentially the same position with respect to an axial direction y of the gear 13 and be spaced a certain distance apart along the circumferential direction x of the gear 13.

[0075] The distance in the x-direction between adjacent active surfaces 23 is greater than one whole tooth pitch p and less than twice the tooth pitch p. An arrangement is also conceivable in which the distance is greater than 2p or less than p, for example less than 0.5p, in particular less than 0.25p.

[0076] The sensors 15a, 15b, 15c, 15d are arranged here such that - viewed in the x-direction - the active surface 23 of sensor 15b lies between the active surfaces 23 of sensors 15a, 15c and the active surface 23 of sensor 15c lies between the active surfaces 23 of sensors 15b, 15d.

[0077] Fig. 3 Figure 1 shows a variant in which the gear 13 is designed as a duplex gear with a first tooth 17a and a second tooth 17b, wherein the teeth of the first tooth 17a are aligned with the teeth of the second tooth 17b in the y-direction (axially). The two tooth profiles 17a, 17b can have identical geometric properties. In this example, the active surfaces 23 of the sensors 15a, 15c are opposite a side of the first tooth 17a having the end faces 28, while the active surfaces 23 of the sensors 15b, 15d are opposite a side of the second tooth 17b having the end faces 28.

[0078] Alternatively, the active surfaces 23 opposite the first toothing 17a can be those of the sensors 15a, 15b and the active surfaces 23 opposite the second toothing 17b can be those of the sensors 15c, 15d.

[0079] The active surfaces 23 can also be opposite a side flank of the respective toothing 17a or 17b.

[0080] As in Fig. 3 As can be seen, the active surfaces 23 opposite the first toothing 17a each have a first position in the y-direction. The active surfaces 23 opposite the second toothing 17b, however, each have a second position in the y-direction that differs from the first position.

[0081] The first positions in the x-direction are the same distance apart as the second positions. However, these distances can also differ.

[0082] Furthermore, in this example, every second position in the x-direction is offset by less than half a tooth pitch p from one of the first positions. The offset can be, for example, between 1 mm and 5 mm. In tests with common gear types, an offset of 3 mm proved particularly suitable for obtaining reliable sensor signals.

[0083] The four sensors 15a, 15b, 15c, 15d can, for example, be mounted on a common plate 29 as a holder, in particular screwed into it, the plate 29 being adjustable at least in the x and y directions relative to the gear 13. For example, a radial distance (relative to a rotation axis of the gear 13 not shown) of each active surface 23 to the teeth 17a or 17b can be set by screwing the respective sensor 15a, 15b, 15c, or 15d more or less deeply into the plate 29. Alternatively or additionally, the plate 29 as a whole can be radially adjustable.

[0084] As in the Figur 2 In schematic representation, it is possible that two of the four sensors 15a, 15b, 15c, 15d are combined to form one measuring channel.

[0085] In the Fig. 2 and Fig. 3 In the examples shown, the first sensor 15a and the third sensor 15c are connected to a first output 30a of the sensor device 27 to form a first measurement channel for providing a first sensor signal 21, while the second sensor 15b and the fourth sensor 15d are connected to a separate second output 30b of the sensor device 27 to form a second measurement channel for providing a second sensor signal 31. The first output 30a is connected via a first signal line to a first input 32a of the signal processing device 19. The second output 30b is connected via a separate second signal line to a second input 32b of the signal processing device 19.

[0086] Accordingly, the sensor signal 21 or 31 can be a superposition of the output signals of different sensors of the same measuring channel over the same period, here a first output signal 21a or 31a with a second output signal 21b or 31b (see also Fig. 4 ).

[0087] Alternatively, each sensor 15a, 15b, 15c, 15d can be connected at its output to its own input of the signal processing unit 19. In this case, there are four measurement channels.

[0088] As in Fig. 2 As shown, the signal processing device 19 can comprise a processor 33 and a memory 35 in which a special computer program is stored. The processor 33 can be configured to execute a method for monitoring a rotary motion of the gear 13 by running the computer program, as described in more detail below.

[0089] In a first step, the sensor signal 21 is received in the signal processing unit 19.

[0090] In a second step, the sensor signal 21 is sampled to detect pulses 25 (see Fig. 4 For this purpose, the first sensor signal 21 can, for example, be sampled for rising edges. The detected pulses 25 are counted by assigning a count value 37 to each pulse 25, or more precisely, to each period comprising a pulse 25, whereby the count value 37 is incremented (here by 1) each time a new pulse 25 is detected. In addition, a time value 39 is determined for each detected pulse 25, which indicates the time interval of the pulse 25 to the next pulse, i.e., the duration of the respective period.

[0091] The count value 37 and the time value 39 of each detected pulse 25 are then processed as follows.

[0092] First, a reference time value 41 is used (see Fig. 2 ) by comparing the count value 37 with a list 43, which assigns a reference time value 41 to each count value 37. The list 43 can be stored in memory 35.

[0093] Next, a deviation of the time value 39 from the selected reference time value 41 is determined.

[0094] The deviation is then used to determine whether gear 13 is rotating at the desired speed. For example, it is detected that gear 13 is rotating too fast if the time value 39 is less than the selected reference time value 41, and too slowly if the time value 39 is greater than the selected reference time value 41.

[0095] If the gear 13 rotates too fast, the signal processing unit 19 can generate a control command in an additional step, which causes the escalator 1 to be brought into a safe state. This is usually achieved by interrupting a safety circuit of the escalator 1, thereby stopping the escalator 1.

[0096] The counting of impulses 25 can continue until the count value 37 of the last counted impulse 25 matches a predefined stop value 45. The counting then starts again from the beginning at a predefined starting value 47 (here at "1").

[0097] The stop value 45 indicates after how many consecutive pulses 25 a specific pulse pattern 49 repeats in the sensor signal 21. In this example, the pulse pattern 49 comprises four consecutive pulses 25. The stop value 45 is therefore "4".

[0098] The pulse pattern 49 can be detected, for example, by evaluating the sensor signal 21. Alternatively, the pulse pattern 49 could be a known pulse pattern, which may be derived, among other things, from the geometric properties of the gear 13 or the chain drive 3. Sensory detection of the pulse pattern 49 is therefore not strictly necessary.

[0099] The detection of pulse pattern 49 can include the following steps.

[0100] The pulses 25 within the recognized pulse pattern 49 are counted by assigning a count value 37 to each pulse 25. The count value 37 (here "4") of the last pulse 25 is stored as the stop value 45.

[0101] In addition, a time value 39 is determined for each impulse 25 within the recognized impulse pattern 49.

[0102] In addition, for each count value 37 that has been assigned to one of the pulses 25 of the detected pulse pattern 49, a reference time value 41 is determined, for example by multiplying the time value 39 of the respective pulse 25 by a certain factor (here by 0.90).

[0103] The resulting reference time values ​​41 are then stored together with the respective count values ​​37 in the list 43.

[0104] Additionally, it can be determined whether the detected pulse pattern 49 is plausible by comparing its total duration, i.e. the sum of all time values ​​39 related to the pulse pattern 49, with a reference duration.

[0105] The reference duration can be determined experimentally and / or calculated, for example, by dividing the distance corresponding to the number of pulses 25 within the pulse pattern 49 by the desired speed of the gear 13. The pulse pattern 49 is only used further if it is plausible. Otherwise, the pulse pattern 49 is discarded. The sensor signal 21 can then, for example, be sampled again to detect a pulse pattern 49. Such a learning phase can last at least as long as it takes for a repeating pulse pattern to be detected with sufficient accuracy.

[0106] By repeatedly performing the aforementioned steps to detect the impulse pattern 49, for example at each start and / or during normal operation of escalator 1, the list 43 can be kept up to date.

[0107] It is also possible to switch between different lists 43, which may be based on different known and / or sensorially detected pulse patterns in the sensor signal 21, for example, if unusual deviations are detected when using one of the lists 43. The number of entries in each list 43 (i.e., the number of value pairs consisting of a count value 37 and a reference time value 41) corresponds to the number of periods within the respective pulse pattern. In the simplest case, the number of periods is two. However, the number of periods can also be, for example, equal to the number of teeth of the gear 13 (or an integer multiple thereof) or equal to the product of the number of teeth of the gear 13 and the number of links in the drive chain 11 and / or any other chain of the chain drive 3 (or an integer multiple thereof).

[0108] Such a method offers the possibility of precise overspeed measurement with the shortest possible reaction time, even when the sensor signal 21 is highly non-uniform. Each individual pulse 25 can be used for overspeed measurement; that is, after each individual pulse 25, a decision can be made as to whether the escalator 1 should be stopped or not. False shutdowns of the escalator 1 due to unevenly distributed pulses 25 within a pulse pattern 49 can thus be avoided by the present method.

[0109] The steps for speed monitoring described above and below using the example of the (first) sensor signal 21 can additionally be carried out in the same (or similar) way using the second sensor signal 31.

[0110] The in Fig. 3 The special arrangement of the active surfaces 23 shown has the effect that both sensor signals 21, 31 are generated in such a way that each pulse 25 in the first sensor signal 21 partially overlaps in time with a pulse 25 in the second sensor signal 31 (see Fig. 4 This means that between the two edges of each pulse 25 of the first sensor signal 21, there is exactly one rising edge of the second sensor signal 31 when the gear 13 rotates in one direction, and exactly one falling edge of the second sensor signal 31 when the gear 13 rotates in the other direction. This fact can be used in an additional step to detect whether the gear 13 is rotating in the desired direction. If the gear 13 is not rotating in the desired direction, a control command to bring the escalator 1 into a safe state can be generated in an additional step, as with speed monitoring.

[0111] Finally, it should be noted that terms such as "have," "comprise," "include," "with," etc., do not exclude other elements or steps, and indefinite articles 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 foregoing embodiments may also be used in combination with features or steps described with reference to other of the foregoing embodiments. Reference numerals in the claims are not to be understood as limiting the scope of the subject matter defined by the claims.

Claims

1. Method for monitoring a rotary movement of a gear (13) in the drive (3) of an escalator (1), the method comprising: receiving a sensor signal (21) generated using at least one sensor (15, 15a, 15c) for scanning a toothing (17, 17a, 17b) of the gear (13) in a signal processing device (19); detecting pulses (25) by scanning the sensor signal (21), wherein the pulses (25) are counted by assigning a count value (37) to each pulse (25), wherein each pulse (25) is further assigned a time value (39) which indicates a time interval between the pulse (25) and the next pulse (25); carrying out the following steps for each detected pulse (25): selecting a reference time value (41) by comparing the count value (37) associated with the detected pulse (25) with a list (43) that assigns reference time values (41) to possible count values (37); determining a deviation of the time value (39) associated with the detected pulse (25) from the selected reference time value (41); detecting from the deviation whether the gear (13) is rotating at a desired speed.

2. Method according to claim 1, wherein the counting of the pulses (25) is started from the beginning if the count value (37) of the last detected pulse (25) corresponds to a stop value (45), wherein the stop value (45) indicates a number of pulses (25) within a pulse pattern (49) repeating in the sensor signal (21).

3. Method according to any of the preceding claims, further comprising: detecting a repeating pulse pattern (49) by sampling the sensor signal (21); wherein the pulses (25) are detected taking into account the detected pulse pattern (49).

4. Method according to claim 3, as dependent on claim 2, wherein the stop value (45) indicates a number of pulses (25) within the detected pulse pattern (49).

5. Method according to claim 3 or 4, wherein detecting the pulse pattern (49) comprises: counting the pulses (25) within the pulse pattern (49) by assigning a count value (37) to each pulse (25); determining a time value (39) for each pulse (25) within the pulse pattern (49), the time value (39) indicating a time interval between the pulse (25) and the next pulse (25); wherein the method further comprises: determining a reference time value (41) for each count value (37) that was assigned to a pulse (25) upon detection of the pulse pattern (49) by multiplying the time value (39) of the corresponding pulse (25) by a factor; saving the reference time values (41) together with the corresponding count values (37) in the list (43).

6. Method according to any of claims 3 to 5, further comprising: determining whether the detected pulse pattern (49) is plausible by comparing a total duration of the detected pulse pattern (49) with a reference duration; wherein the detected pulse pattern (49) is retained if it is plausible and / or discarded if it is not plausible.

7. Method according to any of the preceding claims, wherein the sensor signal (21) was generated using at least two sensors (15a, 15c) for scanning the toothing (17, 17a, 17b) at different scanning points (18), in particular by superimposing output signals (21a, 21b) of the at least two sensors (15a, 15c) over the same period of time.

8. Method according to claim 7, wherein the sensor signal (21) is a first sensor signal (21), and furthermore a second sensor signal (31), which was generated using at least two further sensors (15b, 15d) for scanning the toothing (17, 17a, 17b) at different scanning points (18), in particular by superimposing output signals (21a, 21b) of the at least two further sensors (15b, 15d) over the same period of time, is received by the signal processing device (19); wherein the first sensor signal (21) and the second sensor signal (31) were generated such that each pulse (25) in the first sensor signal (21) partially overlaps in time with a pulse (25) in the second sensor signal (31); wherein the method further comprises: determining a current direction of rotation of the gear (13) by evaluating the first sensor signal (21) together with the second sensor signal (31); and / or using the second sensor signal (31) to detect whether the gear (13) is rotating at the desired speed.

9. Signal processing device (19) comprising a processor (33) configured to carry out the method according to any of the preceding claims.

10. Sensor device (27), comprising: at least four sensors (15a, 15b, 15c, 15d) for scanning a toothing (17, 17a, 17b) of a gear (13) in the drive (3) of an escalator (1) on at least four scanning points (18), each sensor (15a, 15b, 15c, 15d) having an active surface (23) and being mountable such that the active surface (23) is opposite the toothing (17, 17a, 17b) at the corresponding scanning point (18), each sensor (15a, 15b, 15c, 15d) being designed to emit an electrical pulse (25) each time one of the teeth of the toothing (17, 17a, 17b) passes the corresponding active surface (23); at least two outputs (30a, 30b) for connecting the sensor device (27) to at least two inputs (32a, 32b) of a signal processing device (19), wherein a first (30a) of the outputs (30a, 30b) can be connected to a first (32a) of the inputs (32a, 32b) via a first signal line, wherein a second (30b) of the outputs (30a, 30b) can be connected to a second (32b) of the inputs (32a, 32b) via a second signal line, wherein at least two (15a, 15c) of the sensors (15a, 15b, 15c, 15d) are connected to the first output (30a) for providing a first sensor signal (21) and wherein at least two further (15b, 15d) of the sensors (15a, 15b, 15c, 15d) are connected to the second output (30b) for providing a second sensor signal (31).

11. Sensor device (27) according to claim 10, wherein the sensors (15a, 15b, 15c, 15d) can be mounted such that the active surfaces (23) have the same position with respect to an axial direction (y) of the gear (13); or wherein the sensors (15a, 15b, 15c, 15d) can be mounted such that at least two of the active surfaces (23) each have a first position, and at least two further active surfaces (23) each have a second position different from the first position with respect to an axial direction (y) of the gear (13).

12. Sensor device (27) according to claim 11, wherein the first positions are offset from one another in the circumferential direction (x) of the gear (13) by more than one whole tooth pitch (p) of the gear (13); and / or wherein the second positions are offset from one another in the circumferential direction (x) of the gear (13) by more than one whole tooth pitch (p) of the gear (13); and / or wherein the first positions have the same distance from each other in the circumferential direction (x) of the gear (13) as the second positions; and / or wherein each first position is offset from one of the second positions in the circumferential direction (x) of the gear (13) by less than a whole tooth pitch (p) of the gear (13), in particular by less than half a tooth pitch (p) of the gear (13).

13. Escalator (1) or moving walkway, comprising: a drive (3) with a gear (13); at least one sensor (15, 15a, 15b, 15c, 15d) for scanning a toothing (17, 17a, 17b) of the gear (13) on at least one scanning point (18), wherein the sensor (15, 15a, 15b, 15c, 15d) has an active surface (23) and is mounted such that the active surface (23) is opposite the toothing (17, 17a, 17b) at the scanning point (18), wherein the sensor (15, 15a, 15b, 15c, 15d) is designed to emit an electrical pulse (25) each time one of the teeth of the toothing (17, 17a, 17b) passes the active surface (23), or the sensor device (27) according to any of claims 10 to 12, wherein each sensor (15a, 15b, 15c, 15d) of the sensor device (27) is mounted such that the active surface (23) of the corresponding sensor is opposite the toothing (17, 17a, 17b) at the corresponding scanning point (18); the signal processing device (19) according to claim 9.

14. Computer program comprising commands that cause a processor (33) of a signal processing device (19) according to claim 9 to carry out the method according to any of claims 1 to 8 when the computer program is run by the processor (33).

15. Computer-readable medium on which the computer program according to claim 14 is stored.

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