Position detection device for an elevator system with a movable elevator car

Abstract

The invention relates to a position detecting device for an elevator system having a movable elevator car and a stationary positioning tape. The positioning tape extends in a longitudinal direction along a moving direction of the elevator car and has a marked surface with optically readable position-indicating marks. An optical sensor is foreseen facing with its field of view a read-out section of the marked surface of the positioning tape. The read-out section is provided at a longitudinal central position of guide elements. The guide elements are recessed at the read-out section for forming an enlarged window such as not to make a shadow on the positioning tape.

Description

[0001] Position detection device for an elevator system with a movable elevator car.

[0002] Technical background

[0003] The invention relates to a position detection device for an elevator system with a movable elevator car.

[0004] A device for determining the position of an elevator car is known from DE 44 01 977 A1 . If the position of the elevator car is detected, then an elevator control system can derive consequences for the elevator from the detected position, for example a deceleration and stop, a catch-up, an opening of the elevator door and a retraction with the door open. To achieve this, a sensor head is located on the car, preferably on the car roof, in a height-stable and torsion-resistant suspension. Furthermore, there is a so-called positioning tape (sometimes also called band) in the elevator shaft with marks as carriers of information. This is done, for example, by magnetic marks. Also provided in the shaft are a lower and an upper suspension device, non-displaceable with respect to the building and usually a fuse switch for sensing a band break. Instead of magnets, optically detectable marks can also be used. The tape is guided relative to the sensor head by a guiding system.

[0005] Furthermore, an elevator system with a measuring system for determining the absolute car position is known from EP 1 412 274 B1. This elevator system has a length measuring system for determining a car position of an elevator car which can travel along at least one guide rail. In this length measuring system, a code mark pattern mounted parallel to the direction of travel next to the elevator car, 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 are provided.

[0006] It is generally desired to determine the position of an elevator car in a reliable manner. For this purpose it is important to be able to read the marks reliably.

[0007] Brief description of invention

[0008] According to an aspect of the invention, a position detection device for an elevator system is provided, wherein the reading process of code marks applied to the positioning tape is improved. i According to the invention, a position detection device for an elevator system having a movable elevator car and a stationary positioning tape is proposed, wherein

[0009] - the positioning tape extends longitudinally along a direction of movement of the elevator car and has a marked surface with optically readable position indicating markings indicating a longitudinal position along the positioning tape, wherein the position detection device comprises

[0010] - a housing mounted to the elevator car,

[0011] - a pair of guide elements for guiding the positioning tape through the housing, and

[0012] - an optical sensor for sensing the optical position-indicating markings in a read-out section, the optical sensor is arranged to face, with its field of view, the marked surface of the positioning tape , the optical sensor having on the positioning tape (4) a sensing width in a lateral direction, which is perpendicular to the longitudinal direction (5) of the positioning tape (4).

[0013] According to the invention, the guide elements are installed in said housing and extend in a longitudinal direction in parallel to each other,

[0014] - each of the guide elements has a respective laterally inwardly directed longitudinal opening for receiving a respective side edge of the positioning tape for guiding the positioning tape, and further has outside of the read-out section a C-shaped cross section surrounding the respective longitudinal opening, wherein the C-shaped cross section is defined by a first leg portion and a second leg portion (19) each being parallel to the surface of the positioning tape, and a connecting portion interconnecting the first leg portion and the second leg portion to each other, the first and second leg portions facing laterally inwardly from the connecting portion so that the inwardly facing longitudinal openings are arranged between the leg portions, and the first leg portion is arranged on a side which is arranged towards the optical sensor. The position detection device according to the invention further comprises a lighting means provided for illuminating the marked surface in the read-out section, wherein the read-out section is provided at a longitudinally central portion of the guide elements, wherein the first leg portions of the pair of guide elements are separated from each other outside the read-out section by a clear distance, which clear distance is equal to or larger than the sensing width, and wherein - the guide elements are recessed at the read-out section to form an enlarged window.

[0015] By providing the guide elements as a pair of guide elements, easy assembly, disassembly, and insertion of the positioning tape into the guide elements and retention by the guide elements may be enabled. Further, by providing the enlarged window in the read-out section, access to - and thus reliable illumination and readout of - the marked surface of the positioning tape may be improved. In particular, shadowing of the marked surface by the guide elements is reduced. By separating the first leg portions of the pair of guiding elements from each other by the clear distance, which is equal or larger than the width of the field of view of the optical sensor, it is ensured that the position indicating markings do not get damages by the guide elements in an area of the positioning tape in which the optical sensor is reading the position information located on the positioning tape.

[0016] According to a particular embodiment, the guide members may be recessed at the read-out section relative to another non-read-out section at another longitudinal position of the guide elements.

[0017] According to the invention, the C-shaped cross section surrounding the respective longitudinal opening includes two inwardly protruding leg portions. The guide elements may be recessed at the read-out section by at least one of the inwardly protruding leg portions being recessed (e.g., shortened or absent) at the read-out section. For example, both guiding elements may have at least one (and preferably exactly one) of the inwardly protruding leg portions recessed at the read-out section.

[0018] According to an embodiment, the enlarged window is formed at a first side of a plane defined by the tape. According to an embodiment, the optical sensor and the lighting means may be provided at the first side of the plane defined by the tape. According to an embodiment, the enlarged window is formed at the other (second) side of a plane defined by the tape as well.

[0019] According to an embodiment, the respective recessed leg portions of both guide elements being preferably located at the first side of the plane defined by the tape. In an embodiment, the leg portions of both guiding elements located at the other side (second side) of the plane defined by the tape may be non-recessed at the read-out section. According to an embodiment, the opening extends along a longitudinal direction, is preferably a longitudinally extending slot (e.g., a slit or groove). According to an aspect, the opening is accessible from the laterally inward side.

[0020] According to an embodiment, the respective lateral edge of the positioning tape is insertable I inserted into the opening from the laterally inward side so that the edge is located within the opening. The C-shaped cross section surrounds the lateral edge of the positioning tape inserted into the opening.

[0021] The term “longitudinally central portion” does not imply an exact center but a central portion is characterized by substantial longitudinal end portions of the guide elements extending to each longitudinal side from the central portion. Both longitudinal end portions of a guide element extend preferably for at least 20% of the total length of the guide element.

[0022] According to an embodiment, the longitudinal openings are laterally inwardly directed slits provided in the guide element and facing each other to receive the respective lateral portions of the positioning tape therein.

[0023] According to an embodiment, the first and second leg portions of each guide element are disposed along respective portions of the marked surface and the other surface.

[0024] According to an embodiment, the first leg portion of each guide element is disposed on the side of the marked surface of the positioning tape.

[0025] According to an embodiment, the first leg portion is laterally shorter than the second leg portion.

[0026] According to an embodiment, the first leg portion is shorter in a cross section at the read-out section in the lateral direction than a cross section at a remaining portion of the guide element.

[0027] According to an embodiment, the first leg portion is absent in a cross section at the read-out section in the lateral direction compared to a cross section at a remaining section of the guide elements.

[0028] According to an embodiment, the guide elements are removably installed in the housing and can be removed from or inserted into the housing by sliding the guide elements longitudinally relative to the housing. According to an embodiment, the optically readable position indicating markings comprise a bar code or a QR code.

[0029] According to an embodiment, the positioning tape is a polymeric tape.

[0030] According to an embodiment, the dimension of the window is adapted such that no shadow is formed on the positioning tape in the longitudinal direction.

[0031] According to an embodiment, the dimension of the window is adapted such that no particles get onto the encoded tape in the reading area.

[0032] According to an embodiment, an elevator system is provided with a position detection device according to any of the preceding claims.

[0033] Brief description of the Figures

[0034] In the following, an example for the invention is described in more detail with reference to the drawings. There is shown in

[0035] Fig. 1 a sketch illustrating the basic structure of an elevator system according to the invention,

[0036] Fig. 2 a first schematic cross-sectional view illustrating a partial area of a position detection device,

[0037] Fig. 3 a second schematic cross-sectional view illustrating a partial area of a position detection device and

[0038] Fig. 4 a sketch illustrating the enlarged window.

[0039] Description of the Figures and of embodiments

[0040] Fig. 1 shows a sketch illustrating the basic structure of an elevator system 2 according to the invention.

[0041] The elevator system 2 shown has a position detection device 1 arranged in a hoistway and a movable elevator car 3. This movable elevator car 3 is movable in the direction of the double arrow 5 in the vertical direction between a plurality of floors of a building. Said vertical direction is hereinafter also referred to as the longitudinal direction. In particular, the position detection device 1 comprises a housing 8.

[0042] Further, the elevator system comprises a stationary positioning tape 4, which is guided through the housing 8 by a pair of guide elements 9 (shown in Fig. 2) installed in respective slots 8a, 8b of the housing 8.

[0043] The housing 8 is mounted to the elevator car 3. It has the slots 8a and 8b through which the stationary positioning tape 4 extends. This stationary positioning tape 4 extends in longitudinal direction 5 along a direction of movement of the elevator car 3.

[0044] The stationary positioning tape 4 has a marked surface 6, optically readable positionindicating markings 7 being applied to this marked surface 6. These optically readable position-indicating markings 7 contain a bar code or a QR code that can be read and evaluated as the elevator car 3 passes the optically readable positionindicating markings 7. The positioning tape 4 is preferably a polymer tape.

[0045] Fig. 2 shows a first schematic cross-sectional view to explain a partial area of the position detection device 1 .

[0046] This first schematic cross-sectional view shows the housing 8 mounted to the elevator car 3 and some further components positioned in the housing 8. These further components positioned in the housing 8 include the pair of guide elements 9 for guiding the stationary positioning tape 4. These guide elements 9 are installed in the housing 8 and extend longitudinally (in longitudinal direction 5) parallel to each other. Each of these guide elements 9 has a laterally inwardly directed longitudinal opening 10 for receiving a respective side edge of the positioning tape 4 for guiding the positioning tape 4. The guide elements 9 each have a C-shaped cross-sectional area surrounding the respective longitudinal opening 10.

[0047] As can be seen in Figure 2, the guide elements 9 are spaced apart from each other, which will be explained in more details below.

[0048] The longitudinal openings 10 are laterally inwardly facing slits provided in the guide elements 9 to receive therein the respective lateral side portions of the stationary positioning tape 4.

[0049] Each C-shaped cross section is defined by first leg portions 20 and second leg portions 19 parallel to the surface of the positioning tape 4. A connecting portion 21 interconnects the first leg portion 20 and second leg portion 19 to each other so that the first leg portion 20 and second leg portion 19 facing laterally inwardly from the connecting portion 21. Therefore, the inwardly facing longitudinal openings 10 are arranged between the leg portions 20, 19.

[0050] The first and second leg portions 20, 19 are arranged along respective portions of the marked surface 6 of the positioning tape 4 and of the other surface of the positioning tape 4The first leg portion 20 is arranged on the marked surface side 6 of the positioning tape 4. Or in other words, the first leg portion 20 is facing the optical sensor 11 shown in Fig. 3.

[0051] As already described above, the guide elements 9 are spaced apart from each other. To achieve this, the first leg portion 20 of the one guide element 9 is separated from the first leg portion 20 of the other guide element 9 by a clear distance indicated by the double arrow 22 in Fig. 2. In other words, the first leg portions are separated from each other by the clear distance.

[0052] Furthermore the first leg portion 20 can be shorter than the second leg portion 19.

[0053] As shown in Fig. 2 and Fig. 4, the first leg portion 20 has a different length in a lateral direction indicated in Fig. 2 and Fig. 4 by a double-arrow 40 depending on a section within the housing 8. Outside a read-out section 42, which is also referred to as the remaining section or non-read-out section 44, the first leg portion 20 of each guide element 9 has the above-described form, which is indicated in Fig. 2 by the dashed lines. As the first leg portion 20 in the non-read-out section 44 is longer in the lateral direction than in the read-out portion 42, only this difference is indicated in Fig. 2 by the dashed lines. The second leg portion 19 and the connecting portion 21 are the same in the non-read-out section 44 and the read-out section 42 and are indicated in solid lines in Fig. 2.

[0054] In particular the cross-section of the first leg portion 20 within the read-out section 42 is shown by solid lines in Fig. 2. Within the read-out section 42, the first leg portion 20 is shorter in the lateral direction 40 compared to the cross section at the remaining (non-read-out) section 44 of the guide elements 9. In other words, the additional part of the first leg portion 20, present in the remaining section 44 but not in the read-out section 42, is illustrated in Fig. 2 in dashed lines.

[0055] Thus, the guiding element 9 is recessed in the read-out section 42 due to the first leg portion 20 being shorted - or, in other non-illustrated embodiments, absent - in the read-out section 42 relative to the remaining section 44. In case the first leg portion 20 being absent in the read-out section, the cross-section of the guide elements in the read-out section is L-shaped instead of C-shaped.

[0056] In order to install the positioning tape 4 in the housing 8, the guide elements 9 - or at least one of the guide elements 9 - are removably installed in the housing 8 and are adapted to be removed from or inserted into the housing 8 by sliding the guide elements 9 in a longitudinal direction 5 relative to the housing 8.

[0057] Fig. 3 shows a second schematic cross-sectional view for explaining a partial area of the position detection device 1 at the read-out section 42. The general description of Fig. 2 and Fig. 4 also applies to Fig. 3 and vice versa.

[0058] Fig. 3 shows, in addition, an optical sensor 11 facing in the read-out section 42 the marked surface 6 of the positioning tape 4 guided by the guide elements 9 in order to be able to detect the optically readable position indicating markings 7. This read-out section 42 is provided in a longitudinally oriented central part of the housing 8 and thus also of the guide elements 9 installed in the housing 8.

[0059] The optical sensor 11 has a sensing width in the width direction of the positioning tape 4, which corresponds to the lateral direction indicated by the double-arrow 40 in Fig. 4. The sensing width of the optical sensor 11 is measured at the marked surface 6 of the positioning tape 4. This sensing width is selected such, that outside of the read-out section 42 the clear distance 22 between the first leg portions 20 of the guiding elements 9 is equal to or larger than the sensing width of the optical sensor 11 . This ensures that the optically readable position-indicating markings 7 on the positioning tape 4 do not get damaged by the guide elements 9 by moving the car 3 and thus the housing 8 including the guiding elements 9.

[0060] Furthermore, as it is illustrated in Figure 3, lighting means 12 are provided in the housing 8 to illuminate the positioning tape 4 in the read-out section 42, and thus the marked surface 6 of the positioning tape 4. These lighting means 12 are LEDs or other suitable light emitting elements. The lighting means 12 are arranged outside the field of view of the optical sensor 11 for reading the optically readable positionindicating markings 7 on the positioning tape 4. The light emitted from these LEDs is directed toward said read-out section 42 as an LED light beam 15 using angular light guides 16, and passes through an enlarged window 14 on its way there. The enlarged window 14, which is illustrated in Figure 4, is the section of the guide elements 9 which provides a larger opening between the guide elements 9. The enlarged window 14 is formed for the illumination provided by the lighting means 12 to reach the positioning tape 4, while other guide element section(s) (all or some remaining guide element section(s), preferably at both sides of the enlarged window 14 in tape length direction) has / have a narrower opening between them. The opening is only to prevent friction to the optically readable position-indicating markings 7 on the positioning tape 4. The enlarged window is as long as illumination needs to be applied to the positioning tape 4 for reading the optically readable position-indicating markings 7.

[0061] The dimension of the enlarged window 14 is selected such that no shadow falls on the coded positioning tape 4 in the read-out section 42. Furthermore, the dimension of the enlarged window 14 is selected such that no particles reach the coded positioning tape 4 in the read-out area or read-out section.

[0062] As can further be seen from Figure 3, the lighting means 12 and an optical sensor lens 18 are placed inside the housing 8 on a printed circuit board 17.

[0063] Possible advantages of aspects of the invention are based in particular on the fact that the two lateral guide elements 9 for the positioning tape have a recess in the central area in the form of an enlarged window 14. In other words, the two guide elements 9 are recessed in the read-out section 42 in the form of the enlarged window 14. This has the advantageous consequence that no shadow falls on the positioning tape 4 in the area of the read-out section 42 of the positioning tape. Due to the use of said enlarged window 14, it is further achieved in an advantageous manner that no particles fall on the positioning tape in the reading section either.

[0064] The guide elements 9 might be formed by any suitable manufacturing process, for example molding the elements in one piece, by an additive manufacturing process or by a subtractive manufacturing method such as machining just to mention a few methods.

[0065] The positioning tape 4 guided by the two lateral guide elements 9 is advantageously a PET tape printed with a bar code or a QR code. The reading head used is an optical reading head such as an optical camera. List of reference signs

[0066] 1 Position detection device

[0067] 2 Elevator system

[0068] 3 Elevator car

[0069] 4 Stationary positioning tape

[0070] 5 Longitudinal direction

[0071] 6 Marked surface

[0072] 7 Position indicating markings

[0073] 8 Housing

[0074] 9 Guide element

[0075] 10 Longitudinal opening

[0076] 11 Optical sensor

[0077] 12 Lighting means

[0078] 14 Window

[0079] 15 LED light beam

[0080] 16 Light guide for LED

[0081] 17 Printed circuit board

[0082] 18 Optical sensor lens

[0083] 19 Second leg portion

[0084] 20 First leg portion

[0085] 21 Connecting part

Claims

Claims:1 . A position detecting device (1 ) for an elevator system having a movable elevator car(3) and a stationary positioning tape (4), the positioning tape (4) extending in a longitudinal direction (5) along a moving direction of the elevator car and having a marked surface (6) with optically readable position-indicating marks (7) indicative of a longitudinal position along the positioning tape (4), the position detecting device (1 ) comprising:- a housing (8) adapted to be mounted on the elevator car (3);- a pair of guide elements (9) for guiding the positioning tape through the housing (8),- an optical sensor (11 ) for sensing the optical position-indicating marks (7) in a readout section (42), the optical sensor (11 ) is arranged to face, with its field of view, the marked surface (6) of the positioning tape (4) guided by a pair of guide elements (9), the optical sensor (11 ) having on the positioning tape (4) a sensing width in a lateral direction, which is perpendicular to the longitudinal direction (5) of the positioning tape(4); wherein the guide elements (9) are installed in the housing and extend in a longitudinal direction in parallel to each other, each of the guide elements (9) having a respective laterally inwardly facing longitudinal opening (10) for accommodating a respective lateral edge of the positioning tape (4) for guiding the positioning tape (4), and further having outside of the read-out section (42) a C-shaped cross section surrounding the respective longitudinal opening, wherein the C-shaped cross section is defined by first leg portion (20) and second leg portion (19) each being parallel to the surface of the positioning tape (4), and a connecting portion (21 ) interconnecting the first leg portion (20) and second leg portion (19) to each other, the first and second leg portions facing laterally inwardly from the connecting portion so that the inwardly facing longitudinal openings are arranged between the leg portions (19, 20), and the first leg portion (20) is arranged on a side which is arranged towards the optical sensor, characterized in that the position detecting device (1 ) further comprises:- lighting means (12) for illuminating the marked surface in the read-out section (42), wherein- the read-out section (42) is provided at a longitudinally central portion of the guide elements (9),- the first leg portions (20) of the pair of guide elements (9) are separated from each other outside the read-out section by a clear distance (22), which clear distance (22) is equal to or larger than the sensing width, and- the guide elements (9) are recessed at the read-out section (42) for forming an enlarged window (14).

2. A position detecting device according to claim 1 , wherein the longitudinal openings (10) are laterally inwardly facing slits provided in the guide elements (9) and face each other for accommodating respective lateral side portions of the positioning tape (4) therein.

3. A position detecting device according to claim 1 or 2, wherein the first and second leg portions are arranged along respective portions of the marked surface of the positioning tape and of the other surface of the positioning tape.

4. A position detecting device according to claim 3, wherein the first leg portion (20) is arranged on the marked-surface side of the positioning tape.

5. A position detecting device according to one of the preceding claims 1 - 4, wherein the first leg portion (20) is laterally shorter than the second leg portion (19).

6. A position detecting device according to one of the preceding claims 1 - 5, wherein in a cross section at the read-out section, the first leg portion (20) is shorter in lateral direction compared to a cross section at a remaining section of the guide elements.

7. A position detecting device according to claim 6, wherein in a cross section at the read-out section, the first leg portion (20) is absent compared to a cross section at a remaining section of the guide elements.

8. A position detecting device according to one of the preceding claims, wherein the guide elements (9) are removably installed in the housing (8) and are adapted to be removed from or inserted into the housing by sliding the guide elements (9) in a longitudinal direction (5) relative to the housing (8).

9. A position detecting device according to one of the preceding claims, wherein the optically readable position-indicating marks (7) comprise a bar code or a QR code.

10. A position detecting device according to one of the preceding claims, wherein the positioning tape (4) is a polymer tape.11 . A position detecting device according to one of the preceding claims, wherein the dimension of the window (14) is adapted such as not to make a shadow on the positioning tape (4) in the length direction.

12. A position detecting device according to one of the preceding claims, wherein the dimension of the window (14) is adapted such that no particles are going on the coded tape (4) in the reading area.

13. Elevator system comprising a positioning detecting device according to one of the preceding claims.

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