Measuring system for detecting the absolute position of an elevator car in an elevator shaft

Abstract

The invention relates to a measuring system for detecting the absolute position of an elevator car in an elevator shaft. This measuring system comprises: - a tape having a longitudinal direction and a transverse direction running transversely with respect to the longitudinal direction, wherein the tape has barcode elements running in the transverse direction, - a linear optical sensor, and - an optical element which is designed to image a longitudinal portion of the tape onto the linear optical sensor, wherein the optical element is aspherical in order to image the tape in its longitudinal direction onto the linear optical sensor in a locally resolved manner, and in order for at least two subregions of the tape situated at the same longitudinal position of the tape and spaced apart from one another in the transverse direction to be imaged overlapping one another onto the linear optical sensor. The invention also relates to an elevator system which comprises such a measuring system.

Description

[0001] Measuring system for detecting the absolute position of an elevator car in an elevator shaft

[0002] The invention relates to a measuring system for detecting the absolute position of an elevator car in an elevator shaft.

[0003] Elevator systems require the precise absolute position of an elevator car to precisely reach a desired position in the elevator shaft and to meet given safety requirements. For example, it must be ensured that the elevator car cannot overrun the top or bottom floors of a building and / or that a specified maximum speed of the elevator car is not exceeded.

[0004] In such elevator systems, the absolute position of the elevator car can be determined using a magnetized tape located in the elevator shaft, which is provided with absolute position information. This absolute position information is continuously read by sensor electronics. The magnetization of the tape consists, for example, of a defined sequence of magnetic north and south poles that form a binary code. This binary code can be evaluated using Hall sensors or MR sensors to provide the desired position information.

[0005] EP 1412274 B1 discloses an elevator system with a measuring system for determining the absolute car position. This elevator system has a length measuring system for determining the car position of an elevator car that can be moved along at least one guide rail. This length measuring system includes a code mark pattern mounted next to the elevator car parallel to the direction of travel, a code reading device mounted on the elevator car for contactless scanning of the code mark pattern, and an evaluation unit for evaluating scanned code patterns. N consecutive code marks of the code mark pattern form a code word. Code words in an n-digit pseudorandom sequence of different code words are uniquely arranged. The code words form a single-track code mark pattern. A scanned code word represents an absolute car position.The code mark pattern is encoded in Manchester coding, so that a code mark change occurs at most after every second code mark. The code reading device has at least two sensors, which are offset by half a code length mark in the direction of travel, so that upon detection of a code mark change, a first sensor generates a scanning signal, which can be used to control a second sensor for detecting the code word.

[0006] Furthermore, it is already known to use a 1D CMOS sensor to detect barcode patterns. A problem that arises in practice is that this sensor has a high height (2800 μm) to width (62 μm) ratio when reading the barcode image. In other words, this means that only a very small area of ​​the barcode's width is captured when reading the barcode. This makes the sensor very sensitive to contamination or damage to the code.

[0007] The object of the invention is to provide a measuring system for detecting the absolute position of an elevator car in an elevator shaft, in which the sensitivity of the sensor used to read the code on the tape is reduced with respect to contamination of the tape and also with respect to damage to the code on the tape.

[0008] This object is achieved by a measuring system having the features specified in claim 1. Advantageous embodiments and further developments of the invention are specified in the dependent claims 2 to 12. Claims 13 to 15 relate to an elevator system having such a measuring system.

[0009] A measuring system with the features specified in claim 1 has the following components:

[0010] - a tape having a longitudinal direction and a transverse direction running transversely to the longitudinal direction, the tape having barcode elements running transversely,

[0011] - a linear optical sensor and

[0012] - an optical element, wherein the optical element is configured to image a longitudinal section of the strip onto the linear optical sensor, wherein the optical element is aspherical, in order to image the strip in its longitudinal direction in a spatially resolved manner onto the linear optical sensor, and in order to image at least two partial regions of the strip located at the same longitudinal position of the strip and spaced apart from one another in the transverse direction in an overlapping manner onto the linear optical sensor.

[0013] According to one embodiment of the invention, bars of the barcode, which are also referred to as barcode elements, run in the transverse direction of the tape, and the optical element is configured to image transversely spaced partial areas of an imaged barcode in an overlapping manner onto the linear optical sensor.

[0014] Such a measuring system advantageously achieves the following: When reading a barcode on the tape, several different reading areas of the barcode located at the same longitudinal position on the tape can be detected and imaged in a superimposed form on the linear optical sensor. This broadens the read area of ​​the code. This broadening reduces the sensitivity of the optical sensor to contamination of the coded tape and also to damage to the code on the coded tape.

[0015] According to one embodiment of the invention, the tape is designed to be mounted vertically in the elevator shaft along its longitudinal direction. This allows a barcode read from the tape to be used during the movement of an elevator car in the elevator shaft to determine the absolute (vertical) position of the elevator car in the elevator shaft using a sensor device attached to the elevator car. The bars of the barcode preferably extend horizontally.

[0016] According to one embodiment of the invention, the barcode elements form a barcode encoding a vertical position along the tape.

[0017] The barcode can be formed analogously to the code mark pattern known from EP 1412274 B1, whereby, for example, the south poles described in EP 1412274 B1 are depicted as black bars and the north poles as white areas.

[0018] The carrier material for the tape can be, for example, a metal, a textile tape, or even a PET tape based on polyester or polypropylene. Such tapes are described, for example, in US Pat. Nos. 4,750,592 A and 4,433,756 A.

[0019] According to one embodiment of the invention, the optical element is aspherical and is designed to focus at least two points of the strip located at the same longitudinal position and spaced apart from each other in the transverse direction onto the same sensor pixel of the linear optical sensor. The linear optical sensor can, in particular, have a resolution of a plurality of pixels in the longitudinal direction and of one pixel in the transverse direction.

[0020] According to one embodiment of the invention, the optical element is a lens.

[0021] According to one embodiment of the invention, the lens comprises two differently focusing partial lenses. For example, a first partial lens can be arranged to image a first of the partial regions of the strip onto the linear optical sensor, and a second partial lens can be arranged to image a second of the partial regions of the strip onto the linear optical sensor, overlapping with the first partial region. According to one embodiment of the invention, the lens is cast in one piece.

[0022] According to one embodiment of the invention, the lens is aspherical but symmetrical with respect to a plane of symmetry extending in the longitudinal direction of the strip and perpendicular to a surface of the strip and optionally also symmetrical with respect to a further plane of symmetry extending in the transverse direction of the strip and perpendicular to a surface of the strip.

[0023] According to one embodiment of the invention, the optical element images the tape onto the linear optical sensor more sharply in the longitudinal direction than in the transverse direction. This increases the spatial resolution of the read barcode more in the longitudinal direction of the tape than in the transverse direction. This also increases the readability of the read code.

[0024] According to one embodiment of the invention, the optical element is rigidly connected to the linear optical sensor to form a sensor unit. This reduces the space required by the sensor unit.

[0025] According to one embodiment of the invention, the sensor unit is movable in the longitudinal direction relative to the belt.

[0026] According to one embodiment of the invention, the measuring system comprises a housing having a slot on each of two opposite sides for passing the tape through the housing. In this way, for example, a reading area of ​​the tape located between the two slots can be guided through an interior of the housing. The sensor unit can be arranged inside the housing to image the longitudinal section of the tape located inside the housing. Furthermore, the housing and the tape can be movable relative to one another in the longitudinal direction, and the optical element and the linear optical sensor can be fixedly mounted in the housing.

[0027] According to one embodiment of the invention, the belt is fixed vertically in an elevator shaft. According to one embodiment of the invention, the linear optical sensor and the optical element are fixed to a passenger car of the elevator system.

[0028] The above-mentioned embodiments of the invention can be used both individually and - as long as they do not exclude each other - together.

[0029] An exemplary embodiment of the invention is explained in more detail below with reference to the figures. They show:

[0030] - Figure 1 shows an embodiment of the measuring system of an elevator installation, which is designed to detect the absolute position of an elevator car not shown in Figure 1, and

[0031] - Figure 2 shows an embodiment of an elevator system which has such a measuring system.

[0032] Figure 1 shows an exemplary embodiment of a measuring system for an elevator installation. This measuring system is designed to detect the absolute position of an elevator car (not shown in Figure 1). The measuring system shown in Figure 1 includes a barcode-encoded tape 1 having barcode elements 2. This tape is intended to be mounted vertically in an elevator shaft in its longitudinal direction 15. The barcode elements 2 form a barcode encoding a vertical position along the tape. Furthermore, Figure 1 shows a first reading area 3, a second reading area 4, and a tape center line 5. Additional barcode elements are provided on the tape in the dotted areas above and below the center line 5. Furthermore, the measuring system shown in Figure 1 includes an optical element 6, 7, 8, and a linear optical sensor 9.The optical element 6, 7, 8 is a special lens designed to image a longitudinal section of the coded tape onto the linear sensor 9 in a spatially resolved manner and to image at least two reading regions of the tape located at the same longitudinal position of the tape and spaced apart from each other in the transverse direction 16 in an overlapping manner onto the linear optical sensor 9. In the illustrated embodiment, the linear optical sensor 9 is a 1D CMOS sensor.

[0033] The optical element 6, 7, 8 is mounted on a circuit board 10 using fasteners 11 and 12. The linear sensor 9 is also mounted on the circuit board 10 using fasteners 13. Reference numeral 14 denotes the width of the strip 1, reference numeral 15 the longitudinal direction of the strip, and reference numeral 16 the transverse direction of the strip.

[0034] The barcode-encoded band 1 is attached, for example, to a guide rail 15 running vertically, which in turn is arranged on a wall in the elevator shaft of the elevator system. During operation of the elevator system, an elevator car attached to support means moves downwards or upwards in the elevator shaft to let passengers board or disembark at stopping positions on the floors of the elevator shaft. In order to be able to precisely approach the aforementioned stopping positions in the elevator shaft, the elevator system has a measuring system for detecting the absolute position of the elevator car. In this embodiment, the optical element 6, 7, 8 and the linear optical sensor 9 are attached to an outer side of the elevator car.

[0035] The circuit board 10 is attached to the components 6, 7, 8 and 9 on a carrier which is firmly connected to the elevator car and is transported up and down in the elevator shaft together with the elevator car.

[0036] During this transport, the aforementioned components are moved in close proximity to the coded tape 1 permanently mounted in the elevator shaft, allowing the absolute position of the elevator car to be continuously determined during this movement. To determine the absolute position of the elevator car, the barcode on the tape is read, and the desired absolute position of the elevator car is determined from this.

[0037] This happens as follows:

[0038] The aspherically designed special lens 6 is aligned such that two different reading areas 3 and 4 are formed on the barcode present on the tape 1. Each of these two reading areas is designed to capture a portion of the same barcode. The aforementioned alignment of the special lens 6 is illustrated in Figure 1 by different parts 7 and 8 of the special lens, with the first part 7 of the special lens 6 being shown slightly offset toward the tape 1, and the second part 8 of the special lens 6 being shown slightly offset in a direction away from the tape 1.

[0039] The barcode signals read in the two reading areas 3 and 4, which correspond to two points on the tape located at the same longitudinal position of the tape and spaced apart from each other in the transverse direction, are focused on the same sensor pixel of the linear optical sensor 9.

[0040] By focusing the barcode signals read in the two reading areas 3 and 4 on the same sensor pixel, the read barcode is broadened compared to the prior art. This broadening of the read barcode reduces the sensitivity of the linear sensor 9 to contamination of the coded tape and also to damage to the code on the coded tape. This leads to a more reliable determination of the position of the elevator car in the elevator shaft and also enables, for example, an improved response when safety-relevant problems occur in the elevator shaft, such as when the elevator car passes over an upper or lower stop position in the elevator shaft.In the embodiment described above, the possibility of dividing a barcode on the tape into two different reading areas and of mapping the barcode signals detected in these different reading areas onto one another by means of a linear sensor 9 was provided by using the special lens 6, which has two interconnected, differently focused partial lenses 7 and 8.

[0041] This special lens 6, which consists of two differently focusing partial lenses 7 and 8, can be a component that is cast in one piece.

[0042] According to one embodiment of the invention, said special lens 6 is symmetrical with respect to a plane of symmetry extending in the longitudinal direction of the strip and perpendicular to a surface of the strip.

[0043] According to a further embodiment of the invention, the special lens images the belt onto the linear optical sensor 9 more sharply in the longitudinal direction 15 than in the transverse direction 16. This corresponds to an improved spatial resolution of the read barcode in the longitudinal direction of the belt. This, in turn, improves the readability of the barcode and enables an increased accuracy with which an elevator car can be stopped at a desired height position.

[0044] According to a further embodiment not shown in the figures, by using a special lens consisting of three or more interconnected and differently focusing parts, it is possible to provide the possibility of dividing the barcode on the tape into three or more different reading areas and of mapping the barcode signals determined in these different reading areas onto the same pixel of the linear sensor.

[0045] This superimposed imaging of the barcode signals read in the three or more reading areas results in a greater widening of the read barcode compared to the prior art. This greater widening of the read barcode and the imaging of the wider barcode on the linear sensor further reduce the sensitivity of the linear sensor to contamination of the coded tape and damage to the code on the coded tape. In many cases, this leads to further improved positioning of the elevator car at a desired target position in the elevator shaft and also enables a further improved response when safety-relevant problems occur in the elevator shaft, for example, when the elevator car passes over an upper or lower stop position in the elevator shaft.

[0046] A further embodiment of the invention involves rigidly connecting the optical element 6, 7, 8 to the linear optical sensor 9 to form a sensor unit. This reduces the space required by the sensor unit, which can be moved together with the elevator car in the elevator shaft relative to the belt.

[0047] According to a further embodiment of the invention, the measuring system, as can be seen from Figure 2, has a housing 17 which has a slot 18 and 19 on two opposite sides of the housing for passing the band 1 through the housing, wherein the housing 17 and the band 1 are movable relative to one another in the longitudinal direction 15 of the band and wherein the optical element 6, 7, 8 and the linear optical sensor 9 are fixedly mounted in the housing 17.

[0048] According to a further embodiment of the invention, the tape 1 is fixed vertically in an elevator shaft 21. This facilitates the reading of a barcode from the tape 1 using a measuring system mounted in the housing 17 on an outer side of a moving elevator car 20 and increases the reliability of the read barcode. This, in turn, increases the accuracy of detecting the absolute position of the elevator car 20 in the elevator shaft 21. List of Reference Symbols

[0049] 1 volume

[0050] 2 Barcode element

[0051] 3 First reading area

[0052] 4 Second reading area

[0053] 5 Band center line

[0054] 6 optical lens; special lens

[0055] 7 Part of the optical lens

[0056] 8 Part of the optical lens

[0057] 9 linear optical sensor

[0058] 10 circuit board

[0059] 11 Fasteners

[0060] 12 fasteners

[0061] 13 Fasteners

[0062] 14 Width of the band

[0063] 15 Longitudinal direction of the belt

[0064] 16 Transverse direction of the belt

[0065] 17 Housing of the measuring system

[0066] 18 Slot in the housing of the measuring system

[0067] 19 Slot in the housing of the measuring system

[0068] 20 elevator cars

[0069] 21 Elevator shaft

[0070] 22 elevator system

Claims

Patent claims 1 . Measuring system for detecting the absolute position of an elevator car in an elevator shaft, the measuring system comprising: - a tape (1) having a longitudinal direction (15) and a transverse direction (16) extending transversely to the longitudinal direction, the tape having barcode elements (2) extending transversely, - a linear optical sensor (9), and - an optical element (6, 7, 8), wherein the optical element is configured to image a longitudinal section of the strip onto the linear optical sensor (9), wherein the optical element (6, 7, 8) is aspherical in order to image the strip in its longitudinal direction in a spatially resolved manner onto the linear optical sensor, and to image at least two partial regions of the strip located at the same longitudinal position of the strip and spaced apart from one another in the transverse direction (16) in an overlapping manner onto the linear optical sensor (9).

2. Measuring system according to claim 1, wherein the barcode elements are formed by lines.

3. Measuring system according to claim 1 or 2, wherein the optical element is configured to image transversely spaced partial regions of an imaged barcode or an imaged barcode element of the barcode in an overlapping manner onto the linear optical sensor.

4. Measuring system according to one of the preceding claims, in which the band is intended to be mounted vertically in the elevator shaft in its longitudinal direction (15).

5. Measuring system according to one of the preceding claims, in which the barcode elements (2) form a barcode encoding a vertical position along the tape.

6. Measuring system according to one of the preceding claims, in which the optical element (6, 7, 8) is designed to focus at least two points of the strip located at the same longitudinal position of the strip and spaced apart from each other in the transverse direction (16) onto the same sensor pixel of the linear optical sensor (9).

7. Measuring system according to one of the preceding claims, wherein the optical element is a lens.

8. Measuring system according to claim 7, wherein the lens comprises two differently focusing partial lenses (7, 8).

9. A measuring system according to claim 6, wherein the lens is integrally molded.

10. Measuring system according to one of claims 7 to 9, wherein the lens is symmetrical with respect to a plane of symmetry extending in the longitudinal direction of the strip and perpendicular to a surface of the strip.

11. Measuring system according to one of the preceding claims, in which the optical element images the strip more sharply in the longitudinal direction (15) than in the transverse direction (16) onto the linear optical sensor (9).

12. Measuring system according to one of the preceding claims, in which the optical element (6, 7, 8) is rigidly connected to the linear optical sensor (9) to form a sensor unit.

13. Measuring system according to claim 12, wherein the sensor unit is movable relative to the belt in the longitudinal direction (15).

14. Measuring system according to one of the preceding claims, which has a housing (17), the housing (17) has a slot (18, 19) on two opposite sides of the housing for passing the band (1) through the housing, the housing and the band are arranged relative to each other in the longitudinal direction (15) are movable and the optical element (6, 7, 8) and the linear optical sensor (9) are fixedly mounted in the housing.

15. Elevator installation (22) with a measuring system according to one of the preceding claims.

16. Elevator installation according to claim 15, in which the belt (1) is fixed vertically in an elevator shaft (21).

17. Elevator installation according to claim 15 or 16, in which the linear optical Sensor (9) and the optical element (6, 7, 8) are arranged in a housing (17) of the measuring system and the housing (17) of the measuring system is fastened to a lift car (20) of the lift installation and the lift car (20) is arranged in a lift shaft (21) so as to be movable in the vertical direction (15).

Images