Method for monitoring a rotary movement of a gear in the drive of an escalator or a 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] Method for monitoring a rotary movement of a gear in the drive of an escalator or a moving walkway

[0002] The present invention relates to a method for monitoring the rotational movement 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 implementing the method, as well as a sensor device and an escalator.

[0003] The monitoring of the rotational speed and / or direction of a gear on an escalator, such as a sprocket on a chain drive for driving a step or pallet belt and / or an escalator handrail, can be carried out, for example, using two inductive sensors located opposite the gear teeth at different scanning points. The number of pulses available to detect the respective movement parameter per revolution is limited by the number of sensors. Using more than two sensors does increase the number of pulses per revolution, i.e. the resolution of the resulting sensor signal. However, this can also lead to signal irregularities that can lead to undesirable measurement inaccuracies despite the increased resolution.

[0004] There may therefore be a need for a method that enables monitoring of a rotational movement of a gear in the drive of an escalator with increased accuracy and / or increased reliability, in particular when more than two sensors are used to simultaneously scan the teeth of the gear.

[0005] Furthermore, there may be a need for a corresponding signal processing device, a corresponding computer program, a corresponding computer-readable medium, a corresponding sensor device and a corresponding escalator.

[0006] 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.

[0007] A first aspect of the invention relates to a method for monitoring a rotational movement 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 gearing in a signal processing device; detecting pulses by scanning the sensor signal, wherein the pulses are counted by assigning a count value to each pulse, wherein each pulse is further assigned a time value indicating a time interval between the pulse and the next pulse; carrying out 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; detecting, based on the deviation, whether the gear is rotating at a desired speed.

[0008] The method can be computer-implemented and executed automatically by a processor, for example a signal processing device of the escalator.

[0009] The method makes it possible to compensate for non-uniformities in the sensor signal, for example due to inaccuracies in the gear and / or the sensor and / or due to the so-called polygon effect in a chain drive.

[0010] More specifically, the method allows for the selection of a separate threshold value from several possible threshold values ​​for each detected pulse, i.e., for each tooth of the gearing for which a pulse was generated. This allows geometric irregularities in the gearing and / or other inaccuracies, for example, in the alignment of an active surface of the sensor (sensor detection area) to the gearing and / or to each other (e.g., due to wear and / or temperature fluctuations), to 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 value for all sections of the gearing.

[0011] If multiple sensors are used to scan the gear teeth, the individual irregularities described above can result in a sensor signal in which long and short periods alternate regularly. Such a long-short pattern can severely impair the measurement of the gear's rotational speed, particularly if the periods of the long-short pattern are compared to the same reference period, regardless of their respective length. Such irregularities can be effectively compensated for using the method. For example, it can be detected that the gear is rotating too fast if the time value is shorter than the selected reference time value, and / or too slow if the time value is longer than the selected reference time value.

[0012] In this case, a control command to stop the escalator can be generated in an additional step. Such a control command typically interrupts a safety circuit of the escalator.

[0013] It is useful to sample the sensor signal for rising edges, where a 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 a pulse ends, or sampling for both rising and falling edges is also possible.

[0014] The gear can, for example, be a sprocket of a chain drive on the escalator. The chain drive can be designed to drive a step or pallet belt and / or a handrail on the escalator. In this case, the teeth of the sprocket can be connected to a drive pinion of the escalator via a drive chain when the escalator is in operation. In other words, the individual teeth of the sprocket can be used as a measuring element for detecting the rotary movement. This eliminates the need for an additional measuring element, which reduces the cost of manufacturing the escalator. Another option is a gear in the form of an additional measuring gear, which rotates during operation of the escalator but does not transmit any drive forces itself.

[0015] For ease of reading, the terms "escalator and steps" are used exclusively in this description. Naturally, the present inventions are equally applicable to moving walkways with pallets, which is why implementation of the inventions in moving walkways is equally encompassed by the claims.

[0016] A second aspect of the invention relates to a signal processing device having a processor configured to carry out 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 comprise a 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 of the escalator. However, it may also be designed as a unit physically separate from the escalator. Of course, it is also possible for the signal processing device to be implemented in a data cloud (cloud and cloud computing) and use decentralized internet hardware.

[0017] It should be noted that features of the method as described above and below may also be features of the signal processing device (and vice versa).

[0018] A third aspect of the invention relates to a sensor device. The sensor device comprises at least four sensors for sensing the toothing of a gear in the drive of an escalator at at least four sensing points, each sensor having an active surface and being mountable such that the active surface is opposite the toothing at the respective sensing point. Each of these sensors is configured to emit an electrical pulse each time one of the teeth of the toothing 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 is connectable to a first of the inputs via a first signal line, wherein a second of the outputs is connectable 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 for providing a first sensor signal and wherein at least two further sensors are connected to the second output for providing a second sensor signal.

[0019] This allows the use of a simpler and correspondingly cheaper signal processing device compared to sensor devices in which the output of each sensor is connected to a separate input of the signal processing device.

[0020] In addition, such a sensor device enables significantly more precise and / or reliable measurements than designs with fewer than four sensors, for example, with only two sensors or with only one sensor. It also makes it possible to verify the correct functioning of the escalator by comparing the signals from both measurement channels. "Sensor" can be understood above and below, for example, as an inductive sensor, a Hall sensor, an optical sensor, or a combination of at least two of these examples.

[0021] The sensors in the sensor system can be of the same type or of different types. If the sensors are inductive, they can differ from each other in their oscillation frequency, for example. This can prevent the sensors from interfering with each other during operation. However, the inductive sensors can also have the same oscillation frequency.

[0022] Preferably, the sensors can be mounted such that the active surfaces have different positions with respect to a circumferential direction of the gear.

[0023] The sensors can each be mounted using a special mount. Such a mount can be designed to enable precise alignment of the active surface of the respective sensor in three spatial directions—i.e., the x, y, and z directions—with respect to the gear teeth.

[0024] It should be noted that features of the method as described above and below may also be features of the sensor device (and vice versa).

[0025] For example, the method described above and below may further comprise: generating the first sensor signal and / or the second sensor signal by the sensor device described above and below.

[0026] 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 for processing by the method described above and below.

[0027] 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 toothing 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 toothing at the scanning point, wherein the sensor is designed to emit an electrical pulse each time one of the teeth of the toothing passes the active surface; and the signal processing device described above and below. As an alternative to the at least one sensor, the escalator can comprise the sensor device described above and below, wherein each sensor of the sensor device is mounted such 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 process 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 comprises instructions which cause a processor of a signal processing device to carry out the method described above and below when the computer program is executed by the processor.

[0031] The computer-readable medium may be a volatile or non-volatile data storage device. For example, the computer-readable medium may be a hard disk, a USB (universal serial bus) storage device, 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), a flash memory, or a combination of two or more of these examples. The computer-readable medium may also be a data communications network that enables the downloading of program code (e.g., over the Internet), or a cloud.

[0032] It should be noted that features of the method 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 may be considered based on the ideas and findings described below. These embodiments are not to be construed as limiting the scope of the invention.

[0034] According to one embodiment, the counting of the pulses can be started from the beginning when the count value of the last detected pulse matches a stop value that specifies a number of pulses within a pulse pattern repeating in the sensor signal. Counting can be started from the beginning by resetting a counter for counting the pulses to a start value, for example, 0 or 1. Counting then continues from the start value, with the counter being incremented with each detected pulse, for example, by the value 1, until the stop value is reached again. Counting can be performed continuously during operation of the escalator.

[0035] In other words, the set of possible count values ​​that can be assigned to the detected pulses is not indeterminate, but rather limited to certain count values. For example, the set of possible count values ​​can include values ​​for counting to four (e.g., "0, 1, 2, 3" or "1, 2, 3, 4") if the repeating pulse pattern includes four consecutive pulses.

[0036] The repeating pulse pattern can be a known pulse pattern with a known number of pulses. The known pulse pattern can, for example, result from the configuration of a chain drive on the escalator that contains the gear. It is also possible that the pulse pattern was determined in tests or in one or more separate long-distance runs before or parallel to normal operation of the escalator.

[0037] In the simplest case, the stop value can be equal to 2. In this case, the repeating pulse pattern comprises exactly two consecutive pulses. However, the stop value can also be significantly greater than 2. For example, the stop value can be equal to a number of teeth on the gear (or an integer multiple thereof) and / or equal to a number of links in the drive chain (or an integer multiple thereof). In other words, the stop value can be equal to a number of pulses generated by sampling the sensor signal using the sensor(s) during one or more complete revolutions of the gear and / or the drive chain in the same direction.

[0038] It's possible that the pulse pattern changes during escalator operation, for example, due to temperature fluctuations or increasing wear. Therefore, it's useful to automatically scan the sensor signal for recurring pulse patterns and determine a corresponding stop value from them.

[0039] Therefore, according to one embodiment, the method may further comprise a step in which a repeating pulse pattern is detected by sampling the sensor signal. In this case, the pulses can be detected taking the detected pulse pattern into account. This enables automatic detection of repeating pulse patterns in the sensor signal.

[0040] For this purpose, the sensor signal can be scanned 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 certain events are detected). Detection can occur, for example, during a long-distance run of the escalator, in which the gear wheel is rotated 360 degrees or an integer multiple of 360 degrees in the same direction. Alternatively, the gear wheel can also be rotated by less than 360 degrees during the long-distance run.

[0041] It is possible for several repeating pulse patterns to be detected by sampling the sensor signal. The detected pulse patterns can differ from one another in at least one of the following ways, for example: the number of pulses, the time intervals between the pulses, or the total duration. Accordingly, a separate list with 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. It is therefore possible to switch between the different lists several times during escalator operation. It is also conceivable for the sensor signal to be evaluated simultaneously using several such lists. This creates a certain degree of redundancy, which improves the reliability of the process.

[0042] According to one embodiment, the stop value can specify a number of pulses within the detected pulse pattern. In other words, upon detection of the pulse pattern, it is possible, among other things, to determine how many pulses the pulse pattern consists of and set a corresponding stop value (for example, with four pulses, a stop value of "4" for a count from 1 to 4 or a stop value of "3" for a count from 0 to 3). This enables automatic updating of the stop value when a new pulse pattern is detected, for example, due to temperature fluctuations and / or increasing wear.

[0043] According to one embodiment, detecting the pulse pattern may 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, wherein the time value indicates a time interval between the pulse and the next pulse. The method may further include: determining a reference time value for each count value assigned to a pulse upon detecting the pulse pattern by multiplying the time value of the respective pulse by a factor; storing the reference time values ​​together with the respective count values ​​in the list.

[0044] In other words, a number of possible count values, which are later used to count the pulses, and the associated reference time values ​​can be determined from the sensor signal. If, for example, the count values ​​"1, 2, 3, 4" (or "0, 1, 2, 3") were assigned one after the other when the pulse pattern was detected, the system will count up to count value 4 (or 3) when the pulses are detected before counting starts again from 1 (or 0). In other words, each count ends after the fourth pulse, i.e. 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 above-mentioned count values. The aforementioned steps can be carried out during a learning phase outside of normal escalator operation and / or in parallel with normal escalator operation.

[0045] This enables automatic updating of the reference time values ​​when a new pulse pattern is detected, for example due to temperature fluctuations and / or increasing wear.

[0046] In addition, the detected pulse pattern can be used to identify properties of the escalator's respective chain drive, for example to determine whether the escalator is equipped with the correct chain drive.

[0047] The factor can, for example, be between 0.80 and 0.95, preferably 0.90.

[0048] According to one embodiment, the method may further comprise a step in which it is determined whether the detected pulse pattern is plausible by comparing a total duration of the detected pulse pattern with a reference duration. The detected pulse pattern is retained if it is plausible and / or discarded if it is not plausible.

[0049] For example, the sensor signal can be resampled in response to the discarding of the pulse pattern to detect a repeating pulse pattern. The total duration of the detected pulse pattern can be measured and / or calculated. Preferably, the total duration is determined by summing the time values ​​of the pulses within the detected pulse pattern.

[0050] The reference duration can, for example, be a quotient of a distance travelled by the gear during the total duration of the detected pulse pattern (i.e. when counting the pulses until the respective stop value is reached) and the desired speed of the gear or can be determined depending on this quotient.

[0051] For example, the detected pulse pattern can 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.

[0052] According to one embodiment, the sensor signal can be generated using at least two sensors for scanning the gearing at different scanning points, in particular by superimposing the output signals of the at least two sensors over the same period of time. In this way, the accuracy of the method can be significantly increased compared to embodiments using only one sensor. Preferably, the sensor signal is generated such that the pulses in the sensor signal do not overlap in time. This enables a clear determination of the number and length of the pulses.

[0053] According to one embodiment, the sensor signal (generated using the at least two sensors) can be a first sensor signal, and a second sensor signal, which was generated using at least two further sensors, in particular by superimposing output signals from the at least two further sensors over the same period of time, 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 in time with a pulse in the second sensor signal. Accordingly, the method can further comprise: determining a 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.

[0054] The direction of rotation can be determined, for example, based on a characteristic sequence of rising and / or falling edges of pulses in a superposition of the two sensor signals over the same period of time or, in other words, based on a characteristic sequence of overlapping pulses of the two sensor signals.

[0055] 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.

[0056] When using the second sensor signal for speed monitoring, the second sensor signal can be processed in the same or similar way as the (first) sensor signal. For example, the two sensor signals can be processed in parallel for this purpose, creating a certain degree of redundancy. This has the advantage that speed monitoring continues to function with sufficient accuracy even if one of the two sensor signals fails or is disrupted for any reason.

[0057] 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 in the circumferential direction of the gear. However, the active surfaces can also partially overlap in the circumferential direction of the gear. Such a linear arrangement of the active surfaces can be advantageous for space reasons.

[0058] Alternatively, the sensors can be mounted such 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 deviating from the first position with respect to an axial direction of the gear.

[0059] If the gear is a duplex gear with a first toothing and a second toothing, the teeth of which are aligned with the teeth of the first toothing in the axial direction of the gear, then, for example, the active surfaces of the first toothing located in the first position and the active surfaces of the second toothing located in the second position can be opposite each other.

[0060] It is possible for the sensors whose active surfaces each have the first position to be connected to the first output of the sensor device, while the sensors whose active surfaces each have the second position are connected to the second output of the sensor device. Alternatively, the sensors whose active surfaces have different positions with respect to the axial direction can be connected to the same output.

[0061] According to one embodiment, the first 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.

[0062] According to one embodiment, the second positions can be offset from one another in the circumferential direction of the gear by more than one whole tooth pitch (p) of the gear.

[0063] The respective offset can, for example, be at least 1.01p, at least 1.1p, or at least 1.5p. Additionally, the respective offset can be less than twice the entire tooth pitch, for example, at most 1.99p, at most 1.9p, or at most 1.6p. This has the effect 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 a clear determination of the number and frequency of the pulses.

[0064] 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.

[0065] 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 a whole 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 favorable. This has the effect that the pulses of a sensor whose active surface has the first position partially overlap in time with the pulses of a sensor whose active surface has the second position, which is offset from the first position. This enables, for example, the detection of the current direction of rotation of the gear (see also above).

[0066] By using such a paired arrangement of the active surfaces, some problems that occurred with the aforementioned linear arrangement could be largely avoided. Embodiments of the invention are described below with reference to the accompanying drawings. Neither the description nor the drawings should be understood as limiting the scope of the invention.

[0067] Fig. 1 shows an escalator according to an embodiment of the invention.

[0068] Fig. 2 shows a sensor device according to an embodiment of the invention.

[0069] Fig. 3 shows a sensor device according to an alternative embodiment of the invention.

[0070] Fig. 4 shows sections of sensor signals as they are processed in a method according to an embodiment of the invention.

[0071] The drawings are purely schematic and not to scale. Where identical reference symbols are used in different drawings, these reference symbols indicate identical or equivalent features.

[0072] Fig. 1 shows an escalator 1 with a chain drive 3 for driving a step belt 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 gear 13 in the form of a sprocket. The gear 13 can be a main drive wheel, which is connected via a shaft to a first drive wheel for driving the step belt 5 and a second drive wheel for driving the handrail 7. The drive pinion 9 can be driven by an electric motor. A gear can be arranged between the drive pinion 9 and the electric motor to transmit rotational movement and torque.

[0073] In addition, the escalator 1 comprises a sensor 15 for scanning a toothing 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 examples. The sensor 15 is arranged such that its active surface 23 lies opposite the toothing 17 at the scanning point 18 at a specific distance. Each time one of the teeth of the toothing 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 the sensor 15. Alternatively, the sensor signal 21 can be based on the output signal.

[0074] As shown in Fig. 2 and Fig. 3, the escalator 1 can alternatively comprise a sensor device 27 with a plurality of sensors for scanning the toothing 17 at a plurality of 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 show a toothed section of the gear 13 in plan view, wherein the head surfaces 28 of the individual teeth are directed towards the plane of the drawing).

[0075] As shown in Fig. 2, the four sensors 15a, 15b, 15c, 15d can, for example, be mounted such that their active surfaces 23 face the same side of the gearing 17, here one of the side flanks of the gearing 17. The active surfaces 23 can have essentially the same position with respect to an axial direction y of the gear 13 and can be spaced apart at a certain distance in the circumferential direction x of the gear 13.

[0076] The distance in the x-direction between adjacent active surfaces 23 is here greater than a whole tooth pitch p and less than twice the tooth pitch p. An arrangement in which the distance is greater than 2p or less than p, for example, less than 0.5p, in particular less than 0.25p, is also conceivable.

[0077] The sensors 15a, 15b, 15c, 15d are arranged here such that - viewed in the x-direction - the active surface 23 of the sensor 15b lies between the active surfaces 23 of the sensors 15a, 15c and the active surface 23 of the sensor 15c lies between the active surfaces 23 of the sensors 15b, 15d.

[0078] Fig. 3 shows a variant in which the gear 13 is designed as a duplex gear with a first toothing 17a and a second toothing 17b, wherein the teeth of the first toothing 17a are aligned with the teeth of the second toothing 17b in the y-direction (axially). The two toothings 17a, 17b can match each other in their geometric properties. In this example, the active surfaces 23 of the sensors 15a, 15c are opposite a side of the first toothing 17a having the tip surfaces 28, while the active surfaces 23 of the sensors 15b, 15d are opposite a side of the second toothing 17b having the tip surfaces 28. Alternatively, the active surfaces 23 opposite the first toothing 17a may be those of the sensors 15a, 15b and the active surfaces 23 opposite the second toothing 17b may 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 can be seen in Fig. 3, 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 are the same distance apart in the x-direction as the second positions. However, the 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, for example, be between 1 mm and 5 mm. In tests with common gear types, an offset of 3 mm proved particularly suitable for obtaining sensor signals that were easy to evaluate.

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

[0084] As shown schematically in Figure 2, it is possible for two of the four sensors 15a, 15b, 15c, 15d to be combined to form one measuring channel.

[0085] In the examples shown in Fig. 2 and Fig. 3, 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 measuring channel for providing a first sensor signal 21, wherein 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 measuring channel for providing a second sensor signal 31. The first output 30a is connected to a first input 32a of the signal processing device 19 via a first signal line. The second output 30b is connected to a second input 32b of the signal processing device 19 via a separate second signal line.

[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 of time, 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 a separate input of the signal processing device 19. In this case, there are four measurement channels.

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

[0089] In a first step, the sensor signal 21 is received in the signal processing device 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 be sampled, for example, 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. The count value 37 is incremented each time a new pulse 25 is detected (here by 1). In addition, a time value 39 is determined for each detected pulse 25, which indicates a time interval between the pulse 25 and the next pulse, i.e., a 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. First, a reference time value 41 (see Fig. 2) is determined by comparing the count value 37 with a list 43 that assigns a reference time value 41 to each count value 37. The list 43 can be stored in memory 35.

[0092] Next, a deviation of the time value 39 from the selected reference time value 41 is determined.

[0093] Based on the deviation, it is finally determined whether gear 13 is rotating at a desired speed. For example, it is determined that gear 13 is rotating too fast if time value 39 is smaller than the selected reference time value 41, or that it is rotating too slowly if time value 39 is greater than the selected reference time value 41.

[0094] If the gear 13 rotates too quickly, the signal processing device 19 can generate a control command in an additional step that causes the escalator 1 to enter a safe state. This is typically achieved by interrupting a safety circuit of the escalator 1, thereby stopping the escalator 1.

[0095] The counting of pulses 25 can continue until the count value 37 of the last counted pulse 25 matches a predefined stop value of 45. The counting then starts again from a predefined start value of 47 (here "1").

[0096] 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."

[0097] The pulse pattern 49 can be detected, for example, by evaluating the sensor signal 21. Alternatively, the pulse pattern 49 can be a known pulse pattern, which can be known, 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 absolutely necessary.

[0098] The detection of pulse pattern 49 may involve the following steps. The pulses 25 within the detected 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.

[0099] In addition, a time value 39 is determined for each pulse 25 within the detected pulse pattern 49.

[0100] In addition, for each count value 37 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).

[0101] The resulting reference time values ​​41 are then stored together with the respective count values ​​37 in the list 43.

[0102] In addition, it can be determined whether the detected pulse pattern 49 is plausible by comparing its total duration, ie the sum of all time values ​​39 related to the pulse pattern 49, with a reference duration.

[0103] The reference duration may have been determined and / or calculated experimentally, for example, by dividing a 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 again 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 until a repeating pulse pattern is detected with sufficient accuracy.

[0104] By repeatedly executing the above steps for detecting the pulse pattern 49, for example at each start and / or during normal operation of the escalator 1, the list 43 can be kept up to date.

[0105] It is also possible to switch between different lists 43, which can be based on different known and / or sensor-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 each 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 on the gear 13 (or an integer multiple thereof) or equal to a product of the number of teeth on the gear 13 and the number of chain links on the drive chain 11 and / or another chain on the chain drive 3 (or an integer multiple thereof).

[0106] Such a method offers the possibility of precise overspeed measurement with the shortest possible response time, even when the sensor signal 21 is highly non-uniform. Each individual pulse 25 can be used for the overspeed measurement, i.e., 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.

[0107] The speed monitoring steps described above and below using the example of the (first) sensor signal 21 can additionally be carried out in the same (or similar) manner using the second sensor signal 31.

[0108] The special arrangement of the active surfaces 23 shown in Fig. 3 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, or exactly one falling edge of the second sensor signal 31 when the gear 13 rotates in the other direction. This circumstance can be used to detect in an additional step whether the gear 13 is rotating in a desired direction. If the gear 13 is not rotating in the desired direction, a control command to transfer the escalator 1 to a safe state can be generated in an additional step, as with speed monitoring.

[0109] Finally, it should be noted that terms such as "comprising," "including," "including," "having," 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 above embodiments may also be used in combination with features or steps described with reference to other of the above embodiments. Reference signs in the claims are not to be understood as limiting the scope of the subject matter defined by the claims.

Claims

Claims 1. A method for monitoring a rotational 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 sampling 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) indicating a time interval between the pulse (25) and the next pulse (25); Perform 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); Detect 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 when 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 one 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. The method according to claim 3 when dependent on claim 2, wherein the stop value (45) indicates a number of pulses (25) within the detected pulse pattern (49). A 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 each a count value (37) is assigned to the 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); the method further comprising: 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 respective pulse (25) by a factor; Storing the reference time values ​​(41) together with the respective count values ​​(37) in the list (43). Method according to one 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. Method according to one of the preceding claims, wherein the sensor signal (21) is determined using at least two Sensors (15a, 15c) for scanning the gearing (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. Method according to claim 7, wherein the sensor signal (21) is a first sensor signal (21) and further comprises receiving a second sensor signal (31) in the signal processing device (19) using at least two further sensors (15b, 15d) for scanning the gearing (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; 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); the method further comprising: 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. A signal processing device (19) comprising a processor (33) configured to carry out the method according to any one of the preceding claims. 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) at at least four scanning points (18), wherein each sensor (15a, 15b, 15c, 15d) has an active surface (23) and can be mounted such that the active surface (23) lies opposite the toothing (17, 17a, 17b) at the respective scanning point (18), wherein each sensor (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 respective 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) is connectable via a first signal line to a first (32a) of the inputs (32a, 32b), wherein a second (30b) of the outputs (30a, 30b) is connectable via a second signal line to a second (32b) of the inputs (32a, 32b), 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); 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 deviating from the first position with respect to an axial direction (y) of the gear (13).Sensor device (27) according to claim 11, wherein the first positions in the circumferential direction (x) of the gear (13) are offset from one another by more than one whole tooth pitch (p) of the gear (13); and / or wherein the second positions in the circumferential direction (x) of the gear (13) are offset from one another by more than one whole tooth pitch (p) of the gear (13); and / or wherein the first positions in the circumferential direction (x) of the gear (13) are at the same distance from one another 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 one whole tooth pitch (p) of the gear (13), in particular by less than half a tooth pitch (p) of the gear (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) at 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 one 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 respective sensor is opposite the toothing (17, 17a, 17b) at the respective scanning point (18); the signal processing device (19) according to claim 9.

14. A computer program comprising instructions that cause a processor (33) of a signal processing device (19) according to claim 9 to execute the method according to one of claims 1 to 8 when the computer program is executed by the processor (33).

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

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