Monitoring of the mechanical condition of an escalator or a moving walkway

Abstract

The application relates to a method for detecting and monitoring the mechanical condition of an escalator or a moving walkway with at least one revolving band and at least one detecting device. The method includes (i) preparing at least one spatial image of at least one section of the revolving band, (ii) selecting at least one region of the spatial image, (iii) comparing the selected region with at least one comparison region, wherein the comparison region is defined by three-dimensional coordinates and represents a virtual space which can be clearly assigned to the selected region, and (iv) generating an alarm signal if the selected region differs from the comparison region by surpassing predetermined limits.

Claims

1. A method for detecting and monitoring the mechanical condition of an escalator or a moving walkway with at least one revolving band and at least one detecting device, the method comprising: creating at least one spatial image of at least one section of the revolving band, selecting at least one region of the spatial image, comparing the selected region with at least one comparison region, the comparison region being defined by three-dimensional coordinates and representing a virtual space that can be clearly assigned to the selected region, and generating an alarm signal if the selected region differs from the comparison region by surpassing predetermined limits, wherein the assignment of the comparison region to the selected region is carried out via reference marks which are assigned to fixed components of the escalator or the moving walkway, wherein the reference marks can be identified in the spatial image and in the corresponding comparison region.

2. The method according to claim 1, wherein at least one distinctive surface or distinctive edge of a tread element or a section of a handrail of the escalator or the moving walkway is selected as selected region of the revolving band.

3. The method according to claim 2, wherein the predetermined limits of the comparison region are surpassed when one or more of the following occur: the selected region projects at least at one location beyond the virtual space; the selected region is missing edges or surfaces; and edges or surfaces of the selected region, by surpassing a predetermined angular tolerance limit, are not arranged parallel to corresponding edges or surfaces of the virtual space.

4. The method according to claim 2, wherein a series of spatial images of the section of the revolving band is captured, and, by comparing the distances of surfaces and edges captured on the images to at least one reference mark image, the spatial image is selected which matches best the assigned comparison region and the virtual reference mark thereof, and at least one selected region of this spatial image is compared with the comparison region.

5. The method according to claim 1, further comprising providing a position determining device that is arranged on fixed components of the escalator or the moving walkway and which detects distinctive surfaces, edges or marks of a tread element or a handrail section of the revolving band and generates a trigger for triggering an image capturing device of the detecting device depending on the current position of the detected surfaces, edges or marks relative to the position determining device.

6. The method according to claim 1, further comprising: analyzing, with an analysis unit, the position of surfaces or edges of the selected region relative to the limits of the comparison region; and determining a positional reserve; and based on the determined positional reserve or through an analysis of a history of a plurality of previously determined and stored positional reserves, the next maintenance date is determined.

7. The method according to claim 6, wherein, from a positional reserve classified by the analysis unit as being maintenance-relevant, the work steps likely to be carried out as well as the maintenance material likely to be needed for maintenance are determined.

8. The method according to claim 1, wherein, for generating and storing the comparison region, a learning movement with a bounding volume element representing the maximum permissible deviations is carried out and the spatial image thereof is stored in a data storage.

9. The method according to claim 1, wherein: a learning movement is carried out with the revolving band intended for operation, a spatial image of a section of the revolving band is prepared, and a comparison region is generated from this spatial image by adding limit values in the form of three-dimensional coordinates to distinctive edges and surfaces of the spatial image.

10. The method according to claim 1, wherein, for checking the functionality of the detecting device, a test movement with at least one test element is carried out, wherein the test element is dimensioned such that it projects at least at one location beyond the comparison region.

11. An escalator or moving walkway comprising: a band arranged in a revolving manner; at least one detecting device for detecting and monitoring a mechanical condition of the escalator or the moving walkway, wherein the detecting device comprises at least one image capturing device configured to generate spatial images, wherein the condition of the revolving band and/or the arrangement of sections of the band relative to fixed components of the escalator or the moving walkway can be detected by the detecting device in that at least one spatial image of a section of the revolving band is generated, distinctive surfaces or edges of the section captured on this image are selectable by a processing unit of the detecting device and are comparable with a three-dimensional comparison region stored in a data storage, wherein that the comparison region can be assigned to the selected region via reference marks, wherein the reference marks are assigned to fixed components of the escalator or the moving walkway and wherein the reference marks are identifiable in the spatial image as well as in the corresponding comparison region.

12. The escalator or moving walkway according to claim 11, wherein the escalator or moving walkway further comprises a position determining device which is arranged on fixed components of the escalator or the moving walkway and through which distinctive surfaces, edges or marks of a tread element or a handrail section of the revolving band can be detected, and through which a trigger for triggering the image capturing device can be generated depending on the current position of the detected surfaces, edges or marks relative to the position determining device.

13. The escalator or moving walkway according to claim 11 wherein the detecting device is arranged between a forward travel of the revolving band and a return travel of the revolving band.

14. The escalator or moving walkway according to claim 11, wherein the image capturing device comprises a transparent protective cover and the detecting device has a cleaning device by which at least a partial surface of the transparent protective cover is cleaned periodically.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Hereinafter, embodiments of the disclosure are described with reference to the accompanying drawings, wherein neither the drawings nor the description are construed as limiting the invention.

(2) FIG. 1 shows an escalator comprising a detecting device according to an embodiment of the present disclosure.

(3) FIG. 2 schematically shows in the detail FIGS. 2A to 2C the main method steps of the method according to an embodiment of the present disclosure, as well as the operating principles of the detecting device.

(4) FIG. 3 shows an escalator step as a section of the revolving band, based on which an incline relative to the intended position is illustrated.

(5) FIG. 4 shows a possible configuration of a bounding volume element suitable for a learning movement.

(6) The Figures are merely schematically and are not true to scale. Same reference signs indicate same or functionally identical features.

DETAILED DESCRIPTION

(7) FIG. 1 shows a side view of an exemplary escalator 1 by means of which persons can be transported, for example, between two levels E1, E2. The escalator 1 has a supporting structure 2 in the form of a truss, which, for the sake of clarity, is illustrated only by contour lines thereof. The supporting structure 2 accommodates components of the escalator 1 and supports them within a building. These components include, for example, balustrades 3 (only one is shown due to the side view), which comprise a handrail 5 arranged in a revolving manner. The balustrades 3 are connected to the supporting structure 2 via balustrade bases 4. The handrail 5 or, respectively, this revolving band 5 is driven via a friction drive 6 which is operatively connected with a drive arrangement 25 of the escalator 1. The correct tension of the handrail 5 is maintained by means of a schematically illustrated handrail tensioning device 7.

(8) The escalator 1 further includes two annularly closed revolving conveyor chains 11, wherein only one of them is shown due to the side view. The two conveyor chains 11 are composed of a plurality of chain links. The two conveyor chains 11 can be displaced along a travel path 8 in travel directions. The conveyor chains 11 run parallel to one another and are spaced apart from one another in a direction transverse to the travel direction. In end regions adjoining the levels E1, E2, the conveyor chains 11 are deflected by deflection sprockets 15, 16.

(9) Between the two conveyor chains 11 there are arranged a plurality of tread elements 9 in the form of tread steps connecting the conveyor chains 11 to one another transverse to the travel path 8. The tread steps 9 can be moved in the travel directions along the travel path 8 by means of the conveyor chains 11. The tread elements 9 guided on the conveyor chains 11 form a step band 10 or, respectively, a revolving band 10 in which the tread elements 9 are arranged one behind the other along the travel path 8 and can be stepped on by users in at least one conveying region 19. The revolving band 10 is guided by schematically illustrated guide rails 12 and supported against gravity. These guide rails 12 are arranged stationarily in the supporting structure 2.

(10) In order to be able to displace the conveyor chains 11, the sprockets 16 of the upper level E2 are connected to the drive arrangement 25. The drive arrangement 25 is controlled by a controller 24 (which is shown schematically only in FIG. 1). The revolving band 10 together with the drive arrangement 25 and the deflection wheels 15, 16 form a conveyor system for users and objects, the tread elements 9 of which can be displaced relative to the supporting structure 2 that is stationarily and fixedly anchored in the building.

(11) As already mentioned above, most of the safety-critical and/or damage-relevant events regarding an escalator 1 or a moving walkway are accompanied by a spatial displacement of moving components from their intended direction of movement. Thereby, imminent damages can be detected in particular by monitoring the revolving bands 5, 10, such as the step band 10 or the revolving handrails 5. In order to achieve this, a detecting device 20, which, in the present example, comprises two image capturing devices 21 and a processing unit 22, is arranged in the escalator 1. The image capturing devices 21 are arranged stationarily on the structure 2 in the transition regions between the horizontal sections of the escalator 1 arranged on the levels E1, E2 and the inclined middle part of the escalator 1. Since in particular the forward travel of the step band 10 loaded by the user is to be monitored and analyzed, the image capturing devices 21 are arranged between the forward travel and the return travel of the step band 10 or, respectively, the revolving band 10. The image capturing devices 21 comprise a detection field a that is limited for technical reasons and that is schematically illustrated in FIG. 1 by dotted lines and the angle α. Accordingly, the image capturing device 21 can only detect a section of the revolving band 10.

(12) The image capturing device 21 arranged in the transition region of the lower level E1 can also detect a sag 28 of the handrail 5. The sag results from an insufficient tension of the handrail 5 by the handrail tensioning device 7 and the gravity at exactly this location.

(13) The two image capturing devices 21 communicate with the processing unit 22 which is arranged in the control cabinet of the controller 24 and is connected thereto. Of course, the detecting device 20 may also comprise an image capturing device 21 and a processing unit 22 which are arranged in a common housing. It is also possible that the processing device 22 is implemented as a pure software application in a computing unit and in a data storage of the controller 24. Of course, there are still further possibilities to arrange the individual parts of the detecting device 20 in the escalator 1 in a decentralized manner.

(14) FIG. 2 schematically shows in the detail FIGS. 2A to 2C the main method steps of the method according to an embodiment of the present disclosure that can be carried out by the detecting device 20.

(15) As already shown in FIG. 1, the image capturing device 21 of the detecting device 20 in FIG. 2A is also arranged stationarily in relation to the guide rails 12 between the forward travel 14 and the non-illustrated return travel. The image capturing device 21 has a hemispherical transparent protective cover 23. In order to periodically clean the latter from dirt and dust, a cleaning device 18 is provided, which, in the present example, is illustrated as a compressed-air blowgun.

(16) FIG. 2A further illustrates a section of the revolving band 10, more precisely, two tread elements 9 of the step band 10. One of the two tread elements 9 has lost a drag roller 13 thereby causing an incline of the tread surface 29 thereof.

(17) For reasons of clarity, the illustration of the conveyor chains 11 arranged on both sides of the tread elements 9 and of the step axles 26 connecting them as well as of the guide rails 12 supporting the conveyor roller 42 has been omitted (these components are shown in FIG. 3). The drag rollers 13 of the tread elements 9 are guided on the two illustrated guide rails 12. One of the guide rails 12 has a reference mark 30, which can also be detected by the image capturing device 21. Since the image capturing device 21 is always arranged stationarily at the same location, position balancing between the reference mark 30 and the image capturing device 21 is not required. However, when preparing the spatial image, the tread element 9 moves relative to the guide rails 12 and the image capturing device 21, which is the reason why here a position balancing and an assignment, respectively, represented by spatial coordinates x, y, z, is required. This can be carried out via the reference mark 30, as described below.

(18) In FIG. 2B, a spatial image 40 of a tread element 9 of the section of the step band 10 shown in FIG. 2A is schematically illustrated by means of dotted lines and image points, respectively. Furthermore, a corresponding virtual space 41 is illustrated by means of dotdashed lines. The spatial image 40 is prepared by the image capturing device 21 which can be, for example, a laser scanner or a time-of-flight-camera. These image capturing devices 21 generating digital images 40 detect three-dimensional structures and image surfaces and edges thereof through a plurality of image points P′, wherein each image point P′, extending from a virtual zero point, is defined by spatial image coordinates x′, y′, z′ and vector coordinates, respectively.

(19) Stationary components can also be imaged at the same time. In the present example, a portion of the guide rails 12 and the reference mark 30 provided on the guide rail 12 as reference mark image 30′ were imaged at the same time. The previously described virtual zero point can be the center of the reference mark image 30′, for example.

(20) The spatial image 40 is transmitted to the processing unit 22 (see FIG. 1). In the processing unit 22, at least one region 27′ of the spatial image 40 is now selected, for example, the image of the riser bottom edge 27 of the tread element 9. The selection is made according to criteria stored in the processing unit 22, for example, based on regions in which a maximum deviation from its original or intended position is to be expected in case of wear or damage.

(21) The processing unit 22 retrieves from an electronic data storage 39 an assigned comparison region 27″. The latter is, for example, a portion of the virtual space 41, which can be retrieved from the data storage 39 and is defined by virtual coordinates x″, y″, z″, and the surfaces and edges of which correspond to a spatial image, changed by limit values, of a section of the revolving band 10 in an original position. To be considered as the original position is the initial condition of this section before it shows a change in position due to wear, damage and contamination. In the virtual space 41, there is a virtual reference mark 30 “. The virtual space 41 illustrated in FIG. 2B serves only as an example of what may serve as a comparison region 27”. Thus, for example, the entire illustrated virtual space 41 can be used as a comparison region 27″. However, it may also be the case that only individual edges 27 or surfaces of a tread element 9, spatially extended by limit values, are stored in relation to the virtual reference mark 30″ as comparison region 27″. Of course, other components of the revolving band 10 can also be imaged in the comparison region 27″.

(22) Moreover, the spatial image coordinates x′, y′, z′ between the reference mark image 30′ and a clearly identifiable point, for example, a point P of the riser bottom edge 27 or, respectively, of the detected image point P′ of the selected region 27′ can be determined in the processing unit 22. If, at the time of preparing the spatial image, the point P of the tread element 9 has the spatial coordinate x, y, z relative to the reference mark 30, logically, the spatial image coordinates x′, y′, z′ of the image point P′ imaged on the spatial image 40 relative to the reference mark 30′, which is also imaged, are identical to the spatial distance coordinates x, y, z. Ideally, clearly identifiable points P are selected.

(23) When a spatial image 40 is made by the image capturing device 21 at an arbitrary point in time, it would be purely accidental if the selected region 27′ of the spatial image 40 has the exact same spatial image coordinates x′, y′, z′ relative to the reference mark image 30′ as the corresponding comparison region 27″ relative to the virtual reference mark 30″. Thus, in a first step, an assignment of a selected region 27′ to a corresponding comparison region 27″ is made.

(24) More precisely, a spatial position difference 4, for example, of the image point P′ relative to the virtual point P″ corresponding thereto of the corresponding comparison region 27″ has to be calculated with the aid of the reference mark image 30′ and the virtual reference mark 30″, and the coordinates of the image points P′ of the selected region 27′ have to be converted with the aid of the calculated position difference 4. Possible optical distortions due to the spatial image 40 prepared in a point-symmetric manner have to be considered as well. According to the previously described assignment, for example, the spatial image 40 of the tread element 9 of a new and unloaded step band 10 is almost congruent with the virtual space 41, and the selected region 27′ with the assigned comparison region 27″, respectively. It is almost congruent because the comparison region 27″ is always larger by limit values than the assigned selected region 27′.

(25) In a second step it can be determined whether or not the image points P′ of the selected region 27′ are still within the assigned comparison region 27″.

(26) This comparison is schematically illustrated in FIG. 2C. Through the assignment, the comparison region 27″ and the selected region 27′ are overlapping one another and the largest deviations can now be determined. In the present example, the spatial image 40 of the tread element 9 deviates from the virtual space 41 in an impermissible manner, illustrated by the angles β and γ. Since the riser bottom edge 27 of the tread element 9 selected as the selected region 27′ has an impermissible angular deviation β, the detecting device 20 generates an alarm signal for the attention of the controller 24, which stops the revolving band 10 immediately and keeps it in place. As can clearly be seen, some regions of the spatial image 40, for example, the bottom edge of the side cheek 31′ of the spatial image 40, project beyond the assigned comparison region 31″. Accordingly, this bottom edge of the side cheek 31′ could also have been selected. The more regions 27′, 31′ of a spatial image 40 are selected and are compared with the comparison regions 27″, 31″, which are clearly assignable, that means, are equivalent in terms of their contour but not necessarily in terms of their position, the more precise can deviations and thus technical problems of the moving band 10 be detected.

(27) FIG. 3 shows a tread element 9 as a section of a revolving band 10. Although the tread surface 29 of the tread element 9 is aligned horizontally, this tread surface has an incline which is shown exaggerated in FIG. 3 and is illustrated by the angle ψ. A possible cause for this incline relative to the intended direction of movement may be irregular signs of wear on the conveyor chains 11 which results in conveyor chains 11 of different lengths. An incline of the tread element 9 may result in an increasing gap between the adjoining balustrade base 4 and the side edge 36 of the tread surface 29 and thereby impermissibly facilitating of objects or limbs of the user getting trapped. In order to detect the incline, the side edges 36 and transverse edges 37 of the tread surface 29 captured on the spatial image 40 can be selected, the corresponding comparison region 36′ can be assigned via the non-illustrated reference point image and the sides edges and transverse edges can be compared therewith.

(28) Based on the example of FIG. 1 it is apparent that the side edges 36 and transverse edges 37 and, respectively, the selected region with the images of these side edges 36 and transvers edges 37, do not yet extend beyond the predetermined limits of the comparison region 36″. However, some locations of the side edges 36 and transverse edges 37 are already close to these limits of the of the comparison region 36″. Preferably, the detecting device 20 comprises an electronic processing unit 22 with an analysis unit 38. By means of the analysis unit 38, the position of surfaces or edges of the selected region relative to the limits of the comparison region 36″ can be analyzed and a positional reserve ψ or, in the present example, the angle ψ of the incline can be determined. Based on the determined positional reserve ψ and/or by an analysis of a history of a plurality of previously determined stored positional reserves ψ or angles ψ, the next maintenance date can be determined. Thereby, imminent damages which can be the reason for serious consequential damages are detected early and their development is monitored.

(29) From a positional reserve ψ that is classified by the analysis unit 38 as being maintenance-relevant, the work steps likely to be carried out and the maintenance material likely to be needed for maintenance, in the present example the conveyor chains 11 including their chain rollers 17, can be determined. Optionally, this can also be carried automatically, for example, by the analysis unit 38.

(30) The sag 28 of the handrail 5 illustrated in FIG. 1 can be monitored in exactly the same way. Here, the assigned comparison region is a tubular virtual space, the central longitudinal axis of which corresponds to the bend in this section of the handrail 5 that exists during start of operation. An excessively tensioned handrail 5 projects beyond the upper limit and an insufficiently tensioned handrail 5 projects beyond the lower limit of the assigned comparison region.

(31) As already mentioned, a position determining device 42 arranged on fixed components of the escalator or the moving walkway can also be provided. It detects distinctive surfaces, edges or marks of a tread element 9 or of a handrail section of the revolving band 5, 10. In FIG. 3, a push switch is arranged as position determining device 42 on one of the guide rails 12. As soon as the axle of a drag roller 13 runs past the position determining device 42, the latter generates a trigger for triggering the image capturing device 21 depending on the current position of the captured surfaces, edges or marks relative to the position determining device 42. Thereby, the spatial images of tread elements 9 are prepared in almost the same position relative to fixed components as the guide rails 12. In other words, the spatial images actually show different tread elements 9; however, all of them have been captured at almost exactly the same spot in relation to the fixed components surrounding them. Thus, where applicable, a correction of distortions of the spatial images can be dispensed with and a comparison with the comparison region can be carried out directly after a completed position balancing via the reference marks.

(32) A possible malfunction of the position determining device 42 is not really a problem because the necessary assignments and corrections can be made at any time through the reference marks. This increases the availability of the detecting device significantly and therefore also the availability of the escalator or the moving walkway.

(33) FIG. 4 shows a possible configuration of a bounding volume element 32 suitable for a learning movement. This bounding volume element 32 for example, is a normal tread element 9 on which the attachment parts 33, 34, 35 representing the limit values are attached. The bounding volume element 32 is now inserted in the revolving band 10 and moved to the image capturing device 21. The spatial image prepared by the image capturing device 21 also includes the reference mark image 30′ described in FIG. 2 and can be processed by the processing unit 22, for example, by correcting distortions due to the point-symmetric imaging by the image capturing device 21. In order to reduce the amount of data and to save storage resources, only the contour lines of this processed spatial image may be stored in the data storage 39 as virtual space 41. Individual regions of this virtual space 41 can then be selected and stored as assignable comparison regions 27″, 31″.

(34) Although the invention(s) has/have been described by illustrating specific exemplary embodiments, it is obvious that numerous further embodiment variants can be created in knowledge of the present disclosure, for example, by combining the features of the individual exemplary embodiments and/or exchanging individual functional units of the exemplary embodiments. For example, the laser scanner itself may be the position determining device, for example, by continuously monitoring a certain location of the space as to whether, for example, a clearly identifiable distinctive part of the body of an escalator step is momentarily present or not. The capturing time can also be triggered by means of the handrail; however, the latter has to be provided with a mark as the distinctive part of the body triggering the trigger. For reasons of better clarity, an illustration of signal transmitting means, power supply lines and the like has been largely omitted in the FIGS. 1 to 4. However, they must inevitably be present in order for the escalator comprising the monitoring device according to the disclosure to be employed without malfunction. Accordingly, correspondingly configured escalators are comprised by the scope of the present patent claims.

(35) Finally, it should be noted that terms such as “including,” “comprising,” etc. do not exclude any other elements or steps and terms such as “a” or “one” do not exclude a plurality. Reference signs in the claims are not to be construed as limitation.