Door system for an elevator system

Abstract

The invention relates to a door system for a lift installation, said door system comprising a door frame which frames a door opening and comprises a first door post. The door system also comprises a first monitoring unit, which is mounted on the door frame, for monitoring a monitoring region of the door opening. At least one first region of the door frame has a first retroreflective surface which extends over at least 20% of the height of the first door post. The first monitoring unit has a light source which is designed to illuminate the first retroreflective surface with light beams. The first monitoring unit comprises a light sensor which is designed to measure the angle-resolved intensity of the light beams reflected by the retroreflective surface. The first monitoring unit determines an output value based on the angle-resolved intensity by detecting when the angle-resolved intensity falls below a threshold intensity for at least one angle. The output value includes an indication of whether there is an obstacle in the monitoring region.

Description

[0001] The present invention relates to a door system for an elevator system.

[0002] In an elevator system, a cabin typically travels vertically along a path between different floors or levels within an elevator shaft. The door system has landing doors on each floor, and the cabin has at least one cabin door. The cabin door and / or landing doors are equipped with a drive mechanism. To allow people or goods to enter or exit the cabin on a given floor, one of the landing doors and the cabin door open simultaneously. To ensure the safe closing of the landing door and the cabin door, the door systems include a monitoring unit that detects obstacles in the doorway—that is, the combined landing door and cabin door assembly. If an obstacle is detected, the unit reverses, prevents, delays, and / or slows down the closing of the doors.

[0003] Application EP2931644 shows a light curtain. A large number of transmitters emitting light and a large number of receivers receiving the light form a system of light beams whose interruption, for example by an obstacle, is detected. This involves wiring a large number of transmitters and receivers, which can be very complex.

[0004] GB 2 453 804 A and US 4 029 176 A also show monitoring systems in the door area with a large number of transmitters and receivers.

[0005] US Patent 6,167,991 B1 describes a surveillance system with numerous transmitters and receivers designed to determine the degree to which the door leaves are open. Additionally, objects outside the doorway are detected by the scattering of light off the objects.

[0006] It can therefore be seen as a task to provide a monitoring unit for a door system that requires less effort to wire.

[0007] The door system according to the invention solves the problem. The door system for an elevator system comprises a door frame that surrounds a door opening and includes a first door jamb. The door system further comprises a first monitoring unit attached to the door frame for monitoring a monitoring area of ​​the door opening. At least a first area of ​​the door frame has a first retroreflective surface. The first monitoring unit has a light source designed to illuminate the first retroreflective surface with light rays. The first monitoring unit includes a light sensor designed to measure the angle-resolved intensity of the light rays reflected from the retroreflective surface.The first monitoring unit determines an output value based on the angle-resolved intensity by monitoring whether the angle-resolved intensity falls below a threshold intensity for at least one angle or range of angles. The output value indicates whether the angle-resolved intensity is below the threshold intensity for at least one of the angles or ranges of angles.

[0008] Possible features and advantages of embodiments of the invention can be considered, among other things and without limiting the invention, as being based on the ideas and findings described below.

[0009] A retroreflective surface reflects an incident light ray essentially back in the direction from which the light ray struck the retroreflective surface. In doing so, the light ray is typically slightly fanned out. A single light ray would thus be spread out upon reflection into a cone with an opening angle. Such an opening angle can be, for example, 1°.

[0010] As mentioned in the introduction, conventional door systems have a large number of light-emitting transmitters and light-receiving receivers. Preferably, the first monitoring unit has only a single light source. The light from the light source can be emitted as a fan of light beams, so that at least the first retroreflective surface is illuminated. It is advantageous to focus the light from the light source onto the retroreflective surface. Alternatively, the light from the light source can be emitted more broadly, i.e., in directions other than just onto the retroreflective surface. The retroreflective surface can also extend adjacent to the first area. Those light beams that are reflected back by the retroreflective surface reach the first monitoring unit. At the first monitoring unit, the light beams are measured by the light sensor.The light sensor is designed to determine the intensity of the light reflected by the retroreflective surface with angular resolution. For this purpose, the light sensor can be configured as a line sensor. In this configuration, the light sensor comprises a series of sensor elements. Optical elements focus the light onto these sensor elements. Light from a specific angle, i.e., from a specific location on the retroreflective surface, is focused onto a single sensor element. The individual measurements from each sensor element can then be combined to determine the angle-resolved intensity.

[0011] Alternatively, angle-resolved intensity can also be determined by swiveling the light source along the retroreflective surface in the form of a narrow beam, such as a laser beam. The beam is so narrow that any obstacle to be detected is larger than the beam's width. This demonstrates the advantage that only a single sensor element is needed to measure the intensity of the light reflected by the retroreflective surface. In this case, the optics are designed to focus the light from all directions within the monitoring area onto the single sensor element. The angle-resolved intensity can then be determined by relating the changing angle of the swiveling, narrow light source over time to the intensity measured by the sensor element at the corresponding time.

[0012] As long as there is no obstruction in the beam path—that is, the path of a light beam from the light source across the retroreflective surface to the light sensor—the angle-resolved intensity of the reflected light is above the threshold intensity for all angles. If an obstruction enters the monitoring area, it prevents the light from the light source from reaching the retroreflective surface because it is scattered or absorbed by the obstruction in other directions. Consequently, the scattered or absorbed light beam cannot be reflected back to the first monitoring unit. The intensity measured by the sensor element for the light beam striking the sensor from an angle at which the obstruction is located decreases. As a result, the angle-resolved intensity of the reflected light falls below the threshold intensity for the angle at which the obstruction is located.This allows the first monitoring unit to at least determine that there is an obstacle in the monitoring area, i.e., in the area of ​​one of the beam paths.

[0013] It can be advantageous to arrange or align the sensor elements so that the angles measured by the sensor elements are always equal. This results in uniform monitoring of the monitored area. As a result, obstacles of the same size and at the same distance from the first monitoring unit can be detected with similar accuracy, regardless of the angle. In particular, the uniform angular spacing makes it easier to calculate the angle assigned to a specific sensor element of the light sensor.

[0014] Preferably, the first monitoring unit determines the output value based on the angle-resolved intensity by detecting when the angle-resolved intensity falls below a threshold intensity for at least seven, preferably adjacent, angles. In other words, the unit detects when the angle-resolved intensity falls below the threshold at seven preferably adjacent sensor elements. This makes the first monitoring unit more robust against minor interference, such as dust or lint.

[0015] According to a preferred embodiment, the height of the first area of ​​the door frame extends over at least 20% of the height of the door opening.

[0016] This allows a significant portion of the door opening to be monitored. Preferably, the retroreflective surface extends over the entire height of the door opening. This allows a single monitoring unit to cover an even larger area. Furthermore, a continuous retroreflective surface is less noticeable to the human eye than a discontinuous one.

[0017] According to a preferred embodiment, the light source is designed to emit infrared light, the retroreflective surface is designed to reflect the infrared light, and the light sensor is designed to measure the angle-resolved intensity of the infrared light.

[0018] The light used is limited to an infrared light spectrum. The retroreflective surface is designed to reflect the infrared light retroreflectively. The light sensor is also preferably designed to measure infrared light specifically. This ensures that primarily only the angle-resolved intensity of the infrared light is measured, and that other light sources not serving the function of the first monitoring unit have no or only a minor effect on the measurement of the angle-resolved intensity.

[0019] Infrared light is invisible to the human eye. This means the light source, and therefore the first line of sight, remains inconspicuous. In particular, the retroreflective surface can be any color visible to the human eye. Specifically, the retroreflective surface can appear black or gray to the human eye, even though it is retroreflective to infrared light. This allows for a free choice of color for the door frame.

[0020] Furthermore, the evaluation of the first monitoring unit is less disturbed by other light sources, since typically no strong infrared light sources are installed or present in or near elevators.

[0021] According to a preferred embodiment, the light source is designed to emit light that is amplitude-modulated at a frequency, the first monitoring unit has an evaluation unit designed to demodulate the angle-resolved intensities, and the first monitoring unit is designed to determine the output value based on the demodulated angle-resolved intensities.

[0022] With amplitude-modulated light, the intensity of the emitted light fluctuates at a specific frequency. This frequency can, for example, range from 100 to 100,000 Hz. A preferred value is between 500 and 1000 Hz. The advantage of modulation is that the first monitoring unit determines the output value in a robust manner. In particular, interference from other light sources is prevented. The probability that a disturbing light source is modulated at the same frequency is extremely low. Especially if the light source is also designed to emit infrared light, the probability of another light source interfering with the first monitoring unit decreases even further. This leads to reliable operation of the first monitoring unit and thus contributes to the safe operation of the elevator system.

[0023] According to a preferred embodiment, the retroreflective surface is applied as a spray layer, paint or as retro tape.

[0024] Retrotape is a thin strip, preferably made of plastic, with a retroreflective surface. Retrotape can be applied by gluing or self-adhesive backing. The retroreflective surface can also be applied by spraying or painting. Preferably, retroreflective particles are dissolved in a solvent along with a binder, creating a brushable or sprayable emulsion. Applying the retroreflective surface to the door frame as a spray, paint, or as retrotape allows for a thin layer of retroreflective material. This thin surface allows passengers or goods to pass through the doorway unimpeded. Furthermore, it is easy to repair if, for example, it becomes worn due to elevator use.The retroreflective surface can simply be covered with adhesive film or painted over without necessarily having to remove the old retroreflective surface. It is also advantageous to mount the retroreflective surface in a recess on the door frame, as this protects it at least partially from scratches.

[0025] According to a preferred embodiment, the first monitoring unit is recessed into the door frame.

[0026] This leaves the doorway completely unobstructed, as there are no protruding elements on the door frame. The monitoring device is recessed into the door frame and thus protected against impacts. Specifically, the monitoring device does not protrude from the door frame and is therefore protected from being bumped and damaged by goods, such as pallets, or by people, for example, by their shoes.

[0027] The sensor's surface preferably forms a continuous surface with the door frame. This means the door frame's surface is essentially flat right up to the first monitoring unit. The first monitoring unit is matched to the door frame in color and texture. If a surface layer of the door frame is transparent to the light used, this layer can extend over the first monitoring unit. In both configurations, the monitoring sensor is inconspicuous.

[0028] According to a preferred embodiment, the first monitoring unit is attached to the door frame of the cabin door.

[0029] The first monitoring unit is mounted on the cabin door frame, i.e., on the cabin itself. The number of cabins in an elevator system is typically much lower than the number of floors it serves. Otherwise, each floor would need its own monitoring unit. Therefore, using the first monitoring unit on the cabin has the advantage of requiring far fewer units overall. Furthermore, connecting the monitoring unit on the cabin to the electrical power supply and / or an electronic data line is easier than connecting it from a floor, since the cabin has multiple power and / or data cables to the elevator control system. The floor doors are often only connected to the elevator control system via the safety circuit. However, the safety circuit is unsuitable, or poorly suited, for power supply or data transmission.

[0030] It can be advantageous to simultaneously install monitoring units on the door frame of the cabin and on the door frame on the floors to achieve particularly secure monitoring.

[0031] According to a preferred embodiment, a second monitoring unit is attached to the door frame.

[0032] According to a preferred embodiment, a third monitoring unit is attached to the door frame.

[0033] By using a second monitoring sensor and optionally a third monitoring sensor, it is possible to monitor a larger area of ​​the door opening than would be possible with just one sensor.

[0034] According to a preferred embodiment, the first monitoring area of ​​the first monitoring unit overlaps with a second monitoring area of ​​the second monitoring unit.

[0035] According to a preferred embodiment, the second monitoring area of ​​the second monitoring unit overlaps with a third monitoring area of ​​the third monitoring unit.

[0036] Overlapping monitoring zones allow for the installation of monitoring units with greater tolerance. The overlapping monitoring zones of the door opening are monitored by at least two monitoring devices. Even if one of these monitoring devices is slightly misaligned, the overlapping monitoring zone is still reliably monitored. Therefore, no gaps occur between the monitoring zones. This results in the advantage that the entire door opening can be monitored without gaps.

[0037] The second and third monitoring units can be constructed identically to the first. This allows for the production of more of this particular type of monitoring unit, thereby reducing unit costs. Furthermore, it eliminates any potential risk of confusion that might arise if the first, second, and third monitoring units were of different designs.

[0038] According to a first alternative embodiment, a first monitoring unit is mounted at a lower end of a first doorpost in such a way as to allow a light beam to pass horizontally over the door threshold, and a further, preferably the second, monitoring unit is mounted at an upper end of the first doorpost or preferably of the opposite second doorpost.

[0039] The door opening is bordered at the bottom by a horizontal sill and at the top by a horizontal lintel. Advantageously, the retroreflective surface is only applied to the door jambs, as it is less exposed to abrasion and damage there than it would be on the sill. The lintel is often unsuitable for applying a retroreflective surface. Often, cutouts are made in the lintel to allow the doors to slide open. Lights may be installed to illuminate the sill so that passengers can see it clearly.

[0040] Obstacles are often located directly on the door threshold. Therefore, it is advantageous for the first monitoring unit to be designed to measure at least one light beam whose path runs horizontally, preferably only a few millimeters above the threshold. Preferably, the beam path runs less than 20 mm above the threshold to detect even thin objects, such as a toe. Preferably, the beam path runs more than 3 mm above the threshold so that dirt particles lying on the threshold cannot interrupt the beam path. The horizontal beam path allows the distance to the horizontal threshold to be kept constant across the width of the threshold. The unmonitored area of ​​the door opening below the light beam is thus negligible. The retroreflective surface on the second door jamb preferably extends down to the threshold.

[0041] The second monitoring unit is preferably mounted at the upper end of the second door jamb. Preferably, the second monitoring unit is just within the first area of ​​the door frame, i.e., where the first retroreflective surface serves for monitoring by the first monitoring unit. The first retroreflective surface can be positioned around or next to the second monitoring unit. The first retroreflective surface can also have a gap at the location of the second monitoring unit. Similarly, the second retroreflective surface can be positioned around or next to the first monitoring unit. It is particularly advantageous if the first and second monitoring areas overlap. Furthermore, the second monitoring unit is mounted at least 1.6 m or more above the door threshold.This is advantageous because regulations in some markets require monitoring of door openings up to a height of at least 1.6 m above the door threshold. Areas above this can be monitored.

[0042] The monitoring area covered by each monitoring unit is limited to beam paths at angles where the light source emits light, the beam path strikes a retroreflective surface, and the light sensor is capable of detecting the reflected light beam. The monitoring areas of all units are essentially triangular. The triangle is formed by a first vertex where the monitoring unit is located. The opposite edge of the triangle is formed by those points on the retroreflective surface illuminated by the light source that reflect the light back to the light sensor in such a way that the sensor can measure the intensity of the light at that angle, and these measurements are then incorporated into the evaluation.

[0043] The area of ​​the door opening below the second monitoring unit is divided into a first and a second right-angled triangular monitoring area, with the lower first monitoring area being monitored by the first monitoring unit and the upper second monitoring area being monitored by the second monitoring unit. The boundary between these two monitoring areas is preferably monitored by both. The second monitoring unit can also partially monitor the area of ​​the door opening above the second monitoring unit. The first monitoring unit essentially monitors the first monitoring area between the first monitoring unit, the second monitoring unit, and a point at the lower end of the second door jamb.The second monitoring unit essentially monitors the second monitoring area between the second monitoring device, the first monitoring device, and a point on the first doorpost that is lower, the same height, or higher than the second monitoring device. Preferably, this point is located at the same distance above the door threshold as the second monitoring unit. The first and second monitoring areas can therefore both be shaped like right-angled triangles that combine to form a rectangle. This rectangle corresponds to at least part of the door opening.

[0044] Furthermore, it is advantageous to position the second monitoring unit only a few millimeters, preferably less than 10 mm, below the door lintel.

[0045] With this arrangement, the entire door opening is monitored. The first monitoring unit essentially monitors the first monitoring area between the first monitoring device, the lower corner of the door opening opposite the first monitoring device, and the second monitoring device. The second monitoring unit essentially monitors the second monitoring area between the second monitoring device, the upper corner of the door opening opposite the second monitoring device, and the first monitoring device.

[0046] Preferably, the retroreflective surface extends over the entire height of the first and second doorposts, and preferably runs around or alongside the monitoring units.

[0047] Preferably, in this embodiment, at least one or each of the monitoring units has a possible beam angle of at least 60°, preferably 90°. This allows even very narrow doors to be monitored from the upper and lower corners.

[0048] According to a second alternative and preferred embodiment, a first monitoring unit is mounted at the lower end of a first door jamb in such a way as to direct a light beam horizontally above the door threshold. A second monitoring unit is mounted on a central area of ​​a second door jamb opposite the first. A third monitoring unit is mounted at the upper end of the first door jamb.

[0049] In this arrangement with three monitoring units, the first monitoring unit is positioned, as described above, such that it is designed to measure at least one light beam whose path runs horizontally, preferably only a few millimeters above the door threshold. This has the same advantages as described above for the first alternative embodiment.

[0050] The second monitoring unit is now mounted centrally on the second doorpost. It is preferably mounted such that the central or angle-bisecting beam path runs horizontally within the monitoring area. This means that of the monitoring area of ​​the second monitoring unit, which preferably has a minimum of 90°, there is an upper monitoring area, preferably encompassing at least 45°, above a horizontal plane at the level of the second sensor, and a lower monitoring area, preferably encompassing at least 45°, below the horizontal plane at the level of the second sensor.

[0051] Preferably, the third monitoring unit is mounted only a few millimeters, preferably less than 10 mm, below the door lintel.

[0052] The first monitoring unit essentially monitors the first monitoring area, which is essentially triangular, between the first monitoring device, the lower corner of the door opening opposite the first monitoring device, and the second monitoring device.

[0053] The second monitoring unit essentially monitors the second monitoring area, which is essentially triangular, between the second monitoring device, the first monitoring device and the third monitoring device.

[0054] The third monitoring unit essentially monitors the third monitoring area, which is essentially triangular, between the third monitoring device, the upper corner of the door opening opposite the third monitoring device, and the second monitoring device.

[0055] Preferably, at least one or each of the monitoring units has a beam angle of slightly more than 90°, for example, 91° to 120°. In particular, the second monitoring unit is installed such that a central beam of the light beam is essentially horizontal. The light beam of the second monitoring unit thus shines downwards at approximately a 45° angle, essentially towards the first monitoring unit, and upwards at a 45° angle, essentially towards the third monitoring unit. Monitoring units of the same design can also be installed as the first and third monitoring units. In this case, for example, the emitted light beam from the first monitoring unit may partially strike the door threshold, while the remaining portion of the beam covers the monitoring area up to the second monitoring unit.This allows for the use of a standardized monitoring unit model. This saves costs and simplifies the inventory management of monitoring units.

[0056] The monitoring unit can be designed to allow users to restrict the area being monitored. For example, the first monitoring area of ​​the first monitoring unit can be restricted so that the door threshold is excluded from the evaluation and cannot be detected as an obstacle. The same applies analogously to all other monitoring devices and their areas not to be monitored, such as the door threshold, lintel, or gaps in the retroreflective surface. Such a restriction of the monitoring area is preferably implemented in the evaluation unit. The evaluation unit can, for example, specifically analyze only the angle-resolved intensities for the angular range being monitored. This means that the other angular ranges are not compared to a threshold intensity.Alternatively, for angle ranges not to be monitored, the threshold intensity can be reduced to a minimum value, so that the measured value is always above the threshold intensity. Preferably, the setting of the angle ranges to be monitored or excluded is transmitted electronically to the respective monitoring unit via a data connection.

[0057] Further advantages, features, and details of the invention will become apparent from the following description of exemplary embodiments and from the drawings, in which identical or functionally equivalent elements are provided with identical reference numerals. The drawings are schematic only and not to scale.

[0058] This shows: Fig. 1 A door system in the open state. Fig. 2 The operating principle of the monitoring unit. Fig. 3 An output of the angle-resolved intensities for the situation in Fig. 2 Fig. 4 A door with several built-in monitoring units.

[0059] Fig. 1 Figure 1 shows a door system 56 in a floor-level view. The door system is recessed into a wall 11. The floor-level door 19 and the cabin door 20 are open. A gap 18 extends between the floor-level door threshold 16 and the cabin-level door threshold 17. This gap 18 ensures that the cabin can travel up and down in the elevator shaft without touching.

[0060] A first monitoring unit 1 is attached to the cabin-side door frame 13, 15 by being recessed into the cabin-side door frame 13, 15. This ensures that the open doors 19, 20, the floor-side door frame 12, 15 and the cabin-side door frame 13, 15 are aligned. They thus form a flat surface.

[0061] The cabin-side door frame 13,15 has a retroreflective surface 14. The one in the Fig. 1 The visible retroreflective surface 14 serves as a retroreflective surface 14 for a second monitoring unit on the right, non-visible, cabin-side door frame. The first monitoring unit 1,41 is mounted at the bottom left of the door opening. The first retroreflective surface for the first monitoring unit 1,41 is mounted on the right door frame. Fig. 1 The first retroreflective surface does not show this.

[0062] Fig. 2 Figure 1 illustrates the operating principle of a monitoring unit 1. The monitoring unit 1 comprises a light source 2 and a light sensor 3. The light source 2 emits light. This light illuminates at least the retroreflective surface 14 located on the opposite side of the door opening. The lowest light beam of the monitored area, measured by the light sensor and evaluated by the evaluation unit, runs horizontally just above the door threshold.

[0063] If a light beam encounters no obstacle, as is the case, for example, for a light beam at an angle α 2, the retroreflective layer reflects the light back essentially in the same direction from which the light beam strikes the retroreflective surface 14. The light beam is slightly widened so that it is not only reflected precisely back to the light source but also falls on the light sensor 3 located directly next to the light source. Without an obstacle, i.e., when the light beam is not interrupted by an obstacle such as a hand or luggage, the light sensor 3 measures a high angle-resolved intensity for a specific angle within the monitoring area. In particular, the angle-resolved intensity is higher than a limiting intensity G.

[0064] If the light beam encounters an obstacle, such as at angles α1 or α3, the light is scattered or absorbed by the obstacle. The obstacle thus prevents the light from reaching the retroreflective surface 14 and being reflected back onto the light sensor 3. In other words, the light beam, scattered or absorbed due to the obstacle, no longer follows the dashed path it would follow without the obstacle. This means that for those angles where an obstacle blocks the light, a low angle-resolved intensity is measured. In particular, the measured angle-resolved intensity is lower than the limiting intensity G.

[0065] Fig. 3 shows an example of a measurement by light sensor 3 for the situation as in Fig. 2 As shown, for angle α1, a first small obstacle 5 scatters or absorbs the light. Therefore, a significant reduction in the measured angle-resolved intensity for angle α1 can be observed. The measured angle-resolved intensity is lower than the defined threshold intensity G. The measured angle-resolved intensity without obstacles can also vary slightly, for example, because the intensity of the reflected light decreases slightly with increasing distance of the retroreflective surface from the first monitoring unit. However, the threshold intensity G is chosen such that the intensity without obstacles remains above the threshold intensity G for all angles.Alternatively, the limiting intensity can be set separately for each individual beam path, for example depending on the distance between the first monitoring unit and the retroreflective surface, so that an optimal limiting intensity is set for each angle.

[0066] For the second larger obstacle 4, the light sensor 3 measures a drop in the angle-resolved intensity below the threshold intensity for several adjacent beam paths in the monitored area. The number of consecutive angle-dependent measured intensities that fall below the threshold intensity is a measure of the size of the obstacle.

[0067] Fig. 4Figure 1 shows a first monitoring unit 1, 41, which is mounted at the bottom left on a first door jamb 47 of the door frame 15. This first monitoring unit 1, 41 covers a first monitoring area 44 from the door threshold 50 to the second monitoring unit 1, 42. The second monitoring unit 1, 42 covers a monitoring area from the first monitoring unit 1, 41 to the third monitoring unit 1, 43 and is mounted on the second door jamb 48, 15. All monitoring units 1 are recessed.

[0068] The second monitoring area, 45, covers an angle of approximately 90°. Monitoring areas 44, 45, and 46 overlap. This allows the entire door opening to be monitored.

[0069] The first monitoring area 44 and the third monitoring area 46 each cover an angle of approximately 45°, although the first and third monitoring units 1, 41, 43 could also cover a monitoring area of ​​90° if, for example, they were installed at the location of the second monitoring unit. The limitation to 45° is therefore only due to the fact that the limitation of the monitoring area preferably occurs during the evaluation process. The hardware of the first monitoring unit and the second monitoring unit is therefore preferably identical.

[0070] The first monitoring device 1, 41 essentially measures the light reflected back through the retroreflective surface 14, 52. A small portion of the light at the lower end of the first retroreflective surface 14, 53 is also reflected to the first monitoring device and measured there. This is a consequence of the overlap of the first monitoring area with the second monitoring area. The third monitoring device 1, 43 essentially measures the light reflected back through the retroreflective surface 14, 53. A small portion of the light at the upper end of the retroreflective surface 14, 52 is also reflected to the third monitoring device and measured there. This is a consequence of the overlap of the third monitoring area with the second monitoring area. The second monitoring device 1, 42 essentially measures the light reflected back through the retroreflective surface 14, 51.This runs essentially the entire height of the first doorpost. It can also run alongside or around the monitoring units, extending all the way to the door threshold and the top of the door lintel.

[0071] The light falling on the door threshold 50 or the door lintel 49 of the door frame 15 is not reflected back to the respective monitoring unit 1, and therefore results in very low measured values ​​for the angle-resolved intensity from these directions. These values ​​would thus remain permanently below the threshold intensity. Therefore, the respective monitoring unit is configured so that the area to be monitored is restricted. For example, the first monitoring area of ​​the first monitoring unit is restricted in such a way that the light paths scattered at the door threshold are excluded from the evaluation, and therefore the door threshold is not detected as an obstacle.

[0072] Finally, it should be noted that terms such as "having," "comprising," etc., do not exclude other elements or steps, and terms 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, within the scope of protection of the present invention as defined by the appended claims 1-14, also be used in combination with other features or steps of other embodiments described above. Reference numerals in the claims are not to be considered as limitations. The term "reflect" in connection with the retroreflective surface refers to a retroreflective reflection, as is also sometimes used with the rather uncommon term "retroreflect."

Claims

1. Door system for an elevator system, comprising a door frame (15) which frames a door opening and comprises a first door jamb (47), a first monitoring unit (1) mounted on the door frame (15) for monitoring a monitoring region (44, 45, 46) of the door opening, wherein at least a first region of the door frame (15) has a first retroreflective surface (14), the first monitoring unit (1) has a light source (2) which is designed to illuminate the first retroreflective surface (14) with light beams, and the first monitoring unit (1) comprises a light sensor (3) which is designed to measure an angle-resolved intensity of the light beams reflected from the retroreflective surface (14), and the first monitoring unit (1) is designed to determine, based upon the angle-resolved intensity, an output value in that the first monitoring unit (1) monitors when the angle-resolved intensity falls below a threshold intensity (G) for at least one angle or angular range, and the output value includes whether the angle-resolved intensity lies below the threshold intensity (G) for at least one of the angles or one of the angular ranges.

2. Door system according to claim 1, characterized in that the first retroreflective surface (14) reflects an incident light beam substantially back in the direction from which the light beam strikes the first retroreflective surface.

3. Door system according to claim 1 or 2, characterized in that the height of the first region of the door frame (15) extends over at least 20% of the height of the door opening.

4. Door system according to any of claims 1 to 3, characterized in that the light source (2) is designed to emit infrared light, and the retroreflective surface (14) is designed to reflect the infrared light, and the light sensor (3) is designed to measure the angle-resolved intensity of the infrared light.

5. Door system according to any of claims 1, 2, or 4, characterized in that the light source (2) is designed to emit light which is amplitude-modulated at a frequency, and that the first monitoring unit (1) has an evaluation unit which is designed to demodulate the angle-resolved intensities, and the first monitoring unit (1) is designed to determine the output value based upon the demodulated, angle-resolved intensities.

6. Door system according to any of claims 1 to 5, characterized in that the retroreflective surface (14) is applied as a spray layer, coating, or as a retrotape.

7. Door system according to any of claims 1 to 6, characterized in that the first monitoring unit (1) is embedded in the door frame (15).

8. Door system according to any of claims 1 to 7, characterized in that the first monitoring unit (1) is mounted on the door frame (15) of the car door (20).

9. Door system according to any of claims 1 to 8, characterized in that a second monitoring unit (1, 42) is mounted on the door frame (15).

10. Door system according to claim 9, characterized in that a third monitoring unit (1, 43) is mounted on the door frame (15).

11. Door system according to any of claims 9 or 10, characterized in that the first monitoring region (44) of the first monitoring unit (1, 41) overlaps with a second monitoring region (45) of the second monitoring unit (1, 42).

12. Door system according to claim 10, characterized in that a second monitoring region (45) of the second monitoring unit (1, 42) overlaps with a third monitoring region (46) of the third monitoring unit (1, 43).

13. Door system according to any of claims 9 to 12, characterized in that a first monitoring unit (1, 41) is mounted on a lower end of the first door jamb (47) oriented in such a way as to allow a light beam to pass horizontally above the door sill (50), and a second monitoring unit (1) is mounted at an upper end of the first door jamb (47) or of the opposite, second door jamb (48).

14. Door system according to any of claims 11 or 12, characterized in that a first monitoring unit (1, 41) is mounted on a lower end of the first door jamb (47) oriented in such a way as to allow a light beam to pass horizontally above the door sill (50), a second monitoring unit (1, 42) is mounted on a central region of a second door jamb (48) opposite the first door jamb (47), and a third monitoring unit (1, 43) is mounted on an upper end of the first door jamb (47).

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