SURVEILLANCE DEVICE

Description

[0001] The invention relates to a monitoring device.

[0002] Such monitoring devices can be provided to secure hazardous areas on systems in which the system carries out hazardous movements.

[0003] In particular, access to a facility can be secured. Access to the facility can be provided by a conveyor belt or similar device, via which transported goods are fed into the facility.

[0004] The monitoring device has at least one safety sensor. The safety sensor can be used to monitor access to the system. The safety sensor monitors a protective field that extends across the entire access area.

[0005] If the safety sensor detects an object, especially a person, in the protective field, a safety function is triggered that puts the system into a safe state so that no further hazards can arise. In particular, the system is shut down.

[0006] To perform work processes within the system, transported goods must be fed into it. If the access is passed through, a safety function triggered by the safety sensor would result in an unnecessary downtime of the system if the transported goods were detected within the protective field.

[0007] Therefore, known monitoring systems provide muting sensors that are positioned upstream of the safety sensor in the direction of transport of the goods. Typically, the muting sensors are formed by light barrier arrays. Based on characteristic sequences of beam interruptions of these light barrier arrays, transported goods can be distinguished from people or other safety-critical objects.

[0008] If the muting sensors detect the transported material, the safety sensor is bypassed, i.e., muted, so that during muting operation, an object entering the protective field of the safety sensor does not trigger the safety function. This allows the transported material to pass the safety sensor without triggering the safety function and shutting down the system.

[0009] After the transported goods have passed the safety sensor, the muting operation is ended and the safety sensor takes over a monitoring function again.

[0010] One problem with this type of muting is that the entire safety sensor is bypassed, thus eliminating any monitoring function. This can lead to dangerous situations, especially if the transported goods do not extend across the entire width of the access. A person standing next to the transported goods can then pass through the access and enter the danger zone of the system unnoticed. This leads to uncontrolled dangerous situations.

[0011] In principle, the areas next to the transported goods could be secured by mechanical protective devices such as pendulum flaps, but this would be structurally complex.

[0012] EP 3 415 804 A1 relates to a safety device with at least one optical safety sensor designed to monitor a planar or spatial monitoring area. Furthermore, the safety device comprises a safety output circuit associated with the safety sensor, having an arrangement of safety outputs controlled as a function of signals from the safety sensor. Switching means are provided by means of which at least one protective field and / or at least one signal field can be activated. The safety sensor generates a safety signal in the form of a deactivation of the safety outputs if the safety sensor detects an object within the activated protective field, or if no permissible object is detected within the activated signal field within a predetermined time interval.

[0013] The invention is based on the object of improving the functionality and safety of a monitoring device of the type mentioned above.

[0014] To achieve this object, the features of claim 1 are provided. Advantageous embodiments and expedient developments of the invention are described in the dependent claims.

[0015] The invention relates to a monitoring device for securing access to a system, comprising an array of safety sensors, each configured to detect objects within a protective field, wherein a safety function is triggered upon detection of an object in at least one protective field. Furthermore, the monitoring device comprises an array of distance sensors, by means of which the position and width of a transport item that can be fed into the system via the access can be detected, as well as a control and evaluation unit, by means of which normal operation is predetermined by the safety sensors monitoring protective fields that complement each other to form an overall protective field that extends across the entire width of the access.With the control and evaluation unit, muting operation can be specified by monitoring protective fields with the safety sensors depending on the position and width of the transported goods determined by the distance sensors, which complement each other to form an overall protective field in which there is a recess in the area of ​​the access that is adapted to the position and width of the transported goods in such a way that the goods can pass through the access without penetrating the overall protective field.

[0016] The arrangement of the safety sensors performs a monitoring function during normal operation such that the protective fields of the safety sensors combine to form an overall protective field that extends across the entire width of the access point, so that the access point is monitored by the safety sensors across its entire extent. If an object intrusion is detected at any location within the overall protective field, it is detected by one of the safety sensors within its protective field, and a safety function is triggered, preventing any further hazards from the system. In particular, the system is shut down.

[0017] The monitoring device according to the invention can further be operated in a muting mode, wherein in the muting mode a transport item can pass the arrangement of the safety sensors without these generating a safety function, i.e. when passing the safety sensors the transport item does not trigger an unnecessary safety function.

[0018] The term "transport goods" generally encompasses any non-safety-critical objects that are to be brought into the facility via the access point. The transport goods are typically fed into the facility via a conveying device such as a conveyor belt. The transport goods can, for example, be pallets.

[0019] According to the invention, distance sensors not only detect the respective transported goods as such, but also detect their width and position, particularly their orientation on the conveyor system.

[0020] Depending on the output signals generated by the distance sensors, a protective field is defined for each safety sensor in the control and evaluation unit for muting operation. The individual protective fields complement each other to form an overall protective field that no longer extends across the entire access area. Instead, the overall protective field includes a recess adapted to the width and position of the transported goods.

[0021] This means that in muting mode, the transported goods can pass through this recess in the overall protection field without the transported goods protruding into the overall protection field, which would trigger the safety function.

[0022] This allows the transported goods to pass through the access without triggering a safety function. Because the recess in the overall protective field is adapted to the width, i.e., the contour, of the transported goods, the overall protective field connects almost seamlessly to the transported goods. This prevents a person or a safety-critical object from passing through the access next to the transported goods unnoticed during muting operation, i.e., without triggering the safety function, significantly increasing the safety of the monitoring device.

[0023] It is particularly advantageous to provide two safety sensors arranged on opposite sides of the access.

[0024] Each safety sensor monitors two-dimensional protective fields that are oriented in a vertical plane.

[0025] During normal operation, the total protective field formed by the protective fields extends over the entire width and height of the access.

[0026] Alternatively, each safety sensor can monitor a three-dimensional area.

[0027] The safety sensors are advantageous as scanning distance sensors.

[0028] In particular, the safety sensors are optical sensors or radar sensors.

[0029] According to an advantageous embodiment, two distance sensors are provided, which are arranged on opposite sides of the access.

[0030] In the simplest case, the distance sensors are one-dimensional distance sensors that emit radiation in a fixed direction.

[0031] In particular, the distance sensors are optical sensors or radar sensors.

[0032] According to an advantageous further development, several distance sensors can be provided at different heights on each side of the access. Alternatively or additionally, scanning distance sensors can also be used. This generates several measured values ​​from which ranges for the position and width of the transported goods can be determined.

[0033] In principle, it is even possible to determine the height of the transported goods. This allows the recess of the overall protective field in muting mode to be adjusted to the height of the transported goods, whereby the overall protective field can then also extend to the area above the transported goods.

[0034] Advantageously, the control and evaluation unit can be formed by a safe controller or by at least one evaluation unit of a safety sensor.

[0035] The control and evaluation unit is used to specify the protective fields in muting mode in such a way that the gaps between the edges of the protective fields and the edges of the transported goods are minimized.

[0036] This ensures that even small safety-critical objects cannot pass through the access during muting operation without a safety function being triggered.

[0037] To specify the protective fields in the muting area, their sizes can be adjusted in steps or continuously to the contour of the transported goods.

[0038] According to an advantageous embodiment, the transported goods are moved in a transport direction towards the system, and the distance sensors are arranged upstream of the safety sensors in the transport direction.

[0039] It is advisable to place the distance sensors upstream of the safety sensors in a range of less than 200 millimeters.

[0040] The arrangement of the distance sensors is thus adapted to the transport direction of the load, allowing the distance sensors to determine the position and width before the load reaches the access monitored by the safety sensors. This allows the protective fields of the safety sensors for muting operation to be defined independently of the output signals of the distance sensors.

[0041] Advantageously, a time control is provided in the control and evaluation unit by means of which the start and end of the muting operation can be specified.

[0042] The output signals of the distance sensors are used in the control and evaluation unit as trigger signals for the start of muting operation.

[0043] For this purpose, a timer is started depending on the detection by means of distance sensors, and after the timer has expired, the muting operation is started.

[0044] Another advantage is that the muting operation is terminated as soon as the transported goods have passed the entire protective field.

[0045] In principle, this can be achieved by controlling the end of the muting operation via an additional timer.

[0046] It is particularly advantageous to monitor a warning field in the area of ​​the recess with the safety sensors during muting operation. Muting operation is terminated as soon as the transported goods have left the warning field.

[0047] Since object detection within the warning field continuously records the transported goods as they pass through the access, this ensures a particularly fail-safe termination of the muting operation.

[0048] According to an advantageous development, additional sensors are arranged upstream of the distance sensors in the transport direction of the transported goods, by means of which the presence of the transported goods can be detected. The evaluation for initiating muting operation is started in the control and evaluation unit when the transported goods are detected by the additional sensors.

[0049] The additional sensors are conveniently located upstream of the safety sensors within a range of 500 millimeters.

[0050] This means that the timing for generating the protective fields in muting mode is optimally adapted to the movement of the respective transported goods.

[0051] This also ensures that the protective fields for muting operation are calculated anew for each transported item, depending on the measured values ​​of the distance sensors.

[0052] The invention is explained below with reference to the drawings. They show: Figure 1: First embodiment of a safety sensor for the monitoring device of the Figures 3 to 5 Figure 2:Second embodiment of a safety sensor for the monitoring device of the Figures 3 to 5 Figure 3: Representation of an embodiment of the monitoring device according to the invention with two safety sensors and two distance sensors as well as a transported item in front of the safety sensors and distance sensors. a) plan view from above, b) side view, c) in a cross-sectional view. Figures 4a - 4c: Arrangement according to the Figures 3a to 3c with transported goods arranged in the area of ​​the distance sensors. Figure 5a - 5c. Arrangement according to the Figures 3a to 3c for transported goods arranged in the area of ​​the safety sensors.

[0053] The Figures 1 and 2show embodiments of safety sensors 1 in the form of distance-measuring optical sensors, wherein the distance measurements are advantageously carried out according to a pulse transit time method or a phase measurement method.

[0054] Figure 1 shows an embodiment of an optical sensor in the form of an area distance sensor, i.e. a scanning distance sensor 12. To carry out distance measurements, the optical sensor has a transmitter 3 emitting light beams 2 and a receiver 4 receiving light beams 2. The transmitter 3 emits light beams 2 in the form of light pulses. Figure 1 shows, the light rays 2 are reflected by an object 5 to be detected, whereby the corresponding light propagation time of the light pulses to the object 5 and back to the optical sensor is evaluated for the distance determination.

[0055] How Figure 1As shown, the sensor components of the optical sensors are integrated in a housing 6, with the transmitter 3 and the receiver 4, with upstream transmitting optics and receiving optics 7, respectively, being arranged stationary in the housing 6. The optical sensor detects objects in a planar detection area by periodically deflecting the light beams 2 by means of a deflection unit 8. The deflection unit 8 is motor-driven and comprises an angle mirror 9 that can be rotated about an axis of rotation D and by which the light beams 2 are deflected.

[0056] Figure 2 shows a variant of the area distance sensor according to Figure 1 In this case, the periodic deflection of the light beams 2 is achieved by arranging the transmitter 3 and the receiver 4 in a measuring head 10 which is rotatable about an axis of rotation D, the measuring head 10 being rotatably mounted on a base 11.

[0057] In general, each safety sensor 1 has an evaluation unit (not shown) in which the received signals from the receiver 4 can be evaluated.

[0058] For use in the field of safety technology, the safety sensors 1 according to the Figures 1 and 2 a fail-safe structure, which can be realized, for example, by a redundant evaluation unit in the form of two cyclically mutually monitoring processors.

[0059] The Figures 3a to 3c , 4a to 4c and 5a to 5c show an embodiment of the monitoring device 100 according to the invention. The monitoring device 100 comprises two safety sensors 1 and two distance sensors 12, which in this case are designed as one-dimensional distance sensors 12 that emit measuring beams 13 in a fixed, predetermined direction. The distance sensors 12 can be designed as optical sensors or as radar sensors.

[0060] The safety sensors 1 are arranged on opposite sides of the access to a facility 200 in the area of ​​its upper limit.

[0061] The distance sensors 12 are arranged at a lower height on both sides of the access to the system 200.

[0062] Access to the system 200 is exclusively via a conveyor belt 14. The area around the system 200 and the conveyor belt 14 is secured laterally by a fence 15.

[0063] The conveyor belt 14 is moved in a transport direction to supply transport material 16 to the system 200.

[0064] The distance sensors 12 are arranged upstream of the safety sensors 1 in the transport direction, for example in a range of 200 millimeters.

[0065] Each safety sensor 1 monitors a protective field 17 which runs in a vertical plane and is thus oriented perpendicular to the surface of the conveyor belt 14.

[0066] A control and evaluation unit (not shown) is provided to control the monitoring device 100. The control and evaluation unit can be implemented as a separate unit within a safe controller. Alternatively, the control and evaluation unit can be formed by an evaluation unit of the safety sensor 1. The measured values ​​of the distance sensors 12 are fed to the control and evaluation unit. Depending on these values, the control and evaluation unit controls the safety sensors 1.

[0067] The Figures 3a to 3c show the monitoring device 100 in normal operation. In this normal operation, a protective field 17 is activated for each safety sensor 1 in such a way that the protective fields 17 complement each other in an overall protective field, with which the access is completely and seamlessly monitored. As can be seen from Figure 3cAs can be seen, the overall protective field formed by the protective fields 17 of the safety sensors 1 extends over the entire width of the conveyor belt 14 and extends upwards to the safety sensors 1.

[0068] If an object 5 or a person penetrates the overall protection field, at least one safety sensor 1 triggers the safety function with which the system 200 is transferred to a safe state, in particular is shut down.

[0069] When arranging the Figures 3a to 3c the transported goods 16 are still in front of the safety sensors 1 and the distance sensors 12. When arranging the Figures 4a to 4c the transported goods 16 are detected by the distance sensors 12, but are not yet in the area of ​​the safety sensors 1, but are immediately before entering the area of ​​the safety sensors 1.

[0070] The control and evaluation unit provides a time control which controls the transition of the monitoring device 100 from normal operation to muting operation and also the duration of the muting operation.

[0071] As soon as the transported material 16 enters the range of the distance sensors 12, the width of the transported material 16 and its position on the conveyor belt 14 are determined based on the measured values, i.e., the output signals of the distance sensors 12. This information is read into the control and evaluation unit.

[0072] The control and evaluation unit uses the output signals of the distance sensors 12 as trigger signals for the start of muting operation. As soon as the distance sensors 12 detect the transported goods 16, a timer is started in the control and evaluation unit. After the timer has expired, muting operation is started when the transported goods 16 are located immediately before entering the area of ​​the safety sensors 1, as shown in the Figures 4a , 4b This timer setting depends on the known transport speed of the conveyor belt 14.

[0073] In muting mode, modified protective fields 17 for the safety sensors 1 were specified via the control and evaluation unit, as shown in Figure 4c The protective fields 17 are dimensioned so that a recess remains between them, which is adapted to the position and width of the transported goods 16 ( Figure 4c ).

[0074] If the transported goods 16 then enter the area of ​​the safety sensors 1 ( Figures 5a to 5c ), it is guided through the recess between the protective fields 17 through the access to the system 200 without the transported goods 16 penetrating the protective fields 17. Thus, the protective fields 17 do not trigger any safety function and the transported goods 16 reach the system 200 without unnecessarily shutting it down.

[0075] The protective fields 17 are dimensioned in muting mode in such a way that the gaps between the edges of the transported goods 16 and the protective fields 17 are minimal.

[0076] To specify the protective fields 17 in the muting area, their sizes can be adjusted in steps or continuously to the contour of the transported goods 16.

[0077] During muting operation, the protective fields 17 monitor the access area adjacent to the transported goods 16. This prevents a person or, in general, a safety-critical object 5 from passing through the access area next to the transported goods 16 unnoticed without triggering a safety function. Because the gaps between the edges of the protective fields 17 and the transported goods 16 are minimized, even small safety-critical objects 5 next to the transported goods 16 in the protective fields 17 are detected during muting operation and trigger the safety function.

[0078] The muting operation is maintained until the transported goods have left the area of ​​the safety sensors 1, i.e. the access monitored by the safety sensors 1.

[0079] In principle, the termination of muting operation can be controlled via another timer.

[0080] It is particularly advantageous to monitor a warning field in the area of ​​the recess with the safety sensors 1 during muting operation.

[0081] The muting operation is then terminated as soon as the transported goods 16 have left the warning field.

[0082] The monitoring device 100 of the Figures 3 to 5 can be further developed in that additional sensors are arranged upstream of the distance sensors 12 in the transport direction of the transported goods 16, by means of which the presence of the transported goods 16 can be detected.

[0083] Then, when the transported goods 16 are detected by the additional sensors, the evaluation for initiating the muting operation is started in the control and evaluation unit. List of reference symbols

[0084] (1)Safety sensor (2)Light beam (3)Transmitter (4)Receiver (5)Object (6)Housing (7)Receiving optics (8)Deflection unit (9)Angle mirror (10)Measuring head (11)Base (12)Distance sensor (13)Measuring beams (14)Conveyor belt (15)Fence (16)Transported goods (17)Protective field (100)Monitoring device (200)System DRotation axis

Claims

1. Monitoring device (100) for safeguarding an access to an installation (200) with an arrangement of one or more safety sensors (1), each of which is designed to detect objects (5) within a protective field (17), a safety function being triggered when an object (5) is detected in at least one protective field (17), and with an arrangement of distance sensors (12), by means of which the position and width of a transport item (16) can be detected, which can be fed to the system (200) via the access, and with a control and evaluation unit, by means of which normal operation is predetermined in that protective fields (17) are monitored with the safety sensors (1), which complement each other to form an overall protective field which extends over the entire width of the access, and characterised in that a muting operation can be preset with the control and evaluation unit in that protective fields (17) are monitored with the safety sensors (1) as a function of the position and width of the transported goods (16) determined with the distance sensors (12), which complement each other to form an overall protective field, in which a recess is present in the area of the access, which is adapted to the position and width of the transported goods (16) in such a way that the latter can pass through the access without penetrating the overall protective field.

2. Monitoring device (100) according to claim 1, characterised in that two safety sensors (1) are provided, which are arranged on opposite sides of the access.

3. Monitoring device (100) according to one of claims 1 or 2, characterised in that each safety sensor (1) is used to monitor two-dimensional protective fields (17) which are oriented in a vertical plane.

4. Monitoring device (100) according to one of claims 1 or 2, characterised in that a three-dimensional area is monitored with each safety sensor (1).

5. Monitoring device (100) according to one of claims 1 to 4, characterised in that the safety sensors (1) are scanning distance sensors (12), and / or in that the safety sensors (1) are optical sensors or radar sensors.

6. Monitoring device (100) according to one of claims 1 to 5, characterised in that two distance sensors (12) in the form of optical sensors or radar sensors are provided, which are provided on opposite sides of the access, wherein in particular the distance sensors (12) are one-dimensional distance sensors (12) which emit radiation in a fixed predetermined direction.

7. Monitoring device (100) according to one of claims 1 to 6, characterised in that the transported goods (16) are moved in a transport direction in the direction of the system (200), and in that the distance sensors (12) are arranged upstream of the safety sensors (1) in the transport direction.

8. Monitoring device (100) according to claim 7, characterised in that the distance sensors (12) are arranged upstream of the safety sensors (1) in a range smaller than 200 millimetres.

9. Monitoring device (100) according to one of claims 6 to 8, characterised in that distance values or ranges of distance values generated in the distance sensors (12) are fed to the control and evaluation unit as analogue or digital signals.

10. Monitoring device (100) according to one of claims 1 to 9, characterised in that the control and evaluation unit is formed by a safety controller or by at least one evaluation unit of a safety sensor (1).

11. Monitoring device (100) according to one of claims 1 to 10, characterised in that the protective fields (17) are preset in muting operation by means of the control and evaluation unit in such a way that the gaps between the edges of the protective fields (17) and the edges of the transported goods (16) are minimised, and / or in that the sizes of the protective fields (17) in the muting area are adapted to the contour of the transported goods (16) in steps or continuously to preset the protective fields (17).

12. Monitoring device (100) according to one of claims 1 to 11, characterised in that a time control is provided in the control and evaluation unit, by means of which the start and end of the muting operation can be preset.

13. Monitoring device (100) according to claim 12, characterised in that the output signals of the distance sensors (12) are used in the control and evaluation unit as trigger signals for the start of muting operation.

14. Monitoring device (100) according to one of claims 12 or 13, characterised in that the muting operation is terminated as soon as the transported goods (16) have passed the overall protective field.

15. Monitoring device (100) according to claim 13, characterised in that a timer is started as a function of detections by means of the distance sensors (12), and in that muting operation is started after the timer has expired, and / or in that the termination of muting operation is controlled via a further timer.

16. Monitoring device (100) according to one of claims 1 to 15, characterised in that a warning field in the area of the recess is monitored during the muting operation with the safety sensors (1).

17. Monitoring device (100) according to claim 16, characterised in that the muting operation is terminated as soon as the transported goods (16) have left the warning field.

18. Monitoring device (100) according to one of claims 7 to 17, characterised in that additional sensors are arranged upstream of the distance sensors (12) in the transport direction of the transported goods (16), by means of which sensors the presence of the transported goods (16) can be detected, wherein the evaluation for initiating the muting operation is started in the control and evaluation unit when the transported goods (16) are detected by the additional sensors.

19. Monitoring device (100) according to claim 18, characterised in that the additional sensors are arranged upstream of the safety sensors (1) in a range of 500 millimetres.