Safety device and method for operating a safety device

Abstract

Safety device (1) for securing access to a danger zone (3), with a separating protective device which can be moved between an open position and a closed position, wherein the separating protective device in its open position allows access to the danger zone (3) and wherein the separating protective device in its closed position blocks access to the danger zone (3), wherein a locking device with or without a guard locking is assigned to the separating protective device, characterized in that a sensor unit (10) is provided which is designed to monitor an access area (3a) to the danger zone (3), characterized in that the locking device and the sensor unit (10) form a structural unit and / or that the locking device and the sensor unit (10) are connected via a data connection.

Description

[0001] The invention relates to a safety device and a method for operating a safety device.

[0002] Such safety devices are used in the field of safety technology, particularly in the field of machine safety.

[0003] A typical monitoring function of a safety device consists in monitoring a separating protective device, such as a protective door, which allows access to a hazardous area on a machine or system.

[0004] Known safety devices have safety switches.

[0005] The operation of a hazardous system within the danger zone is only enabled by a safety controller if the safety switch detects that the guard is in its closed position. For this purpose, the safety switch can, for example, have an RFID reader unit that detects a transponder assigned to the guard. The functionality of the safety switch can be expanded by a guard locking device that locks the guard in its closed position. The guard locking is achieved by retracting a locking element of a locking device, in particular a guard locking pin, into a locked position. An electric or electromagnetic drive is provided to retract the locking element into the locked position.

[0006] US 2020 / 0 372 734 A1 relates to a safety device for securing access to a hazardous area with a guard. The guard is designed to allow or block access to the hazardous area. The guard includes a locking device that locks it. Furthermore, the safety device includes a sensor unit that monitors the access area.

[0007] US 2022 / 0 315 354 A1 concerns a manufacturing system with multiple robots assigned to different work areas. Access to individual work areas is monitored by sensors such as light curtains.

[0008] DE 10 2008 041 844 A1 relates to a printing unit of a printing press with at least two frame parts whose position can be adjusted relative to one another, wherein cooperating frame parts are positioned against one another in a first operating position on a common joining surface and are positioned apart from one another in a second operating position, wherein a gap partially delimited by these frame parts is formed between frame parts positioned apart from one another in the printing unit. A barrier is provided on at least one of the long sides of the printing unit, wherein this barrier is attached to one of the frame parts, wherein access to the gap can be blocked with this barrier, wherein this barrier, in its operating state blocking access to the gap, is designed to be width-variable between the frame parts whose position can be adjusted relative to one another, depending on a movement of these frame parts.

[0009] DE 103 53 889 A1 relates to an automatic protective device for industrial processing systems. To improve the effectiveness of a protective door, a non-contact sensor device is provided for in a protective device for a machine, parallel to an access opening that is covered or uncovered by the protective door(s). The sensor device prevents unintentional or unauthorized access to the area in front of the machine when the protective door is opening or closing.

[0010] DE 10 2021 105 328 A1 relates to a safety switch assembly comprising a safety switch and an associated actuator. The safety switch is integrated in a housing and has an actuator opening into which an actuating element of the actuator can be inserted. The housing is divided into a switch head made of a metallic material and a housing base. To form a secure connection between the switch head and the housing base, receiving elements arranged on the underside of the switch head and corresponding receiving elements on the top of the housing base engage with each other.

[0011] The invention is based on the object of providing a safety device with increased flexibility and functionality.

[0012] To achieve this object, the features of the independent claims are provided. Advantageous embodiments and expedient developments of the invention are described in the dependent claims.

[0013] The invention relates to a safety device for securing access to a hazardous area, comprising a guard that can be moved between an open position and a closed position. In its open position, the guard allows access to the hazardous area. In its closed position, the guard blocks access to the hazardous area. A locking device, with or without a guard locking mechanism, is assigned to the guard. Furthermore, a sensor unit is provided, which is designed to monitor an access area to the hazardous area. The locking device and the sensor unit form a single structural unit and / or are connected via a data link.

[0014] The invention also relates to a corresponding method for operating a safety device.

[0015] The safety device according to the invention is used in the field of safety technology, in particular in the field of machine safety, and for this purpose advantageously has a fail-safe structure that complies with the normative requirements.

[0016] The locking device of the safety device according to the invention implements a safety function such that the locking of a guard is effected and controlled. The locking device can have a locking mechanism that locks the guard when the guard is in its closed position, thus blocking access to a hazardous area.

[0017] The locking mechanism operated in this way prevents unauthorized or uncontrolled access to the danger area.

[0018] Particularly advantageously, the guard is a protective door that can close off access to a hazardous area of a system. Generally, the guard can also be a flap, a door, or similar.

[0019] Advantageously, the locking device consists of a safety module with or without a locking device.

[0020] As a safety module, the safety device can in principle comprise a sensor module, a door module, an actuator, a control and evaluation module or the like.

[0021] The safety module is particularly advantageously designed as a safety switch.

[0022] According to the invention, the safety device comprises a sensor unit that monitors an access area. Access to the danger zone is only possible via this access area, and only when the guard is extended from its closed position, in particular to its open position.

[0023] If the guard is open, it no longer provides protection against access. Especially in this case, the sensor unit provides an additional safety function by detecting whether and which object is entering or exiting the danger zone. The sensor unit can thus determine whether objects, especially safety-relevant objects and people, are present in the danger zone, thus helping to avoid dangerous situations.

[0024] Particularly advantageous is the sensor unit, a distance sensor, by means of which the positions of objects in the access area can be determined.

[0025] The sensor unit is generally designed in such a way that it can detect objects and determine their positions throughout the entire access area.

[0026] According to a first variant, the sensor unit emits radiation at an opening angle, wherein the opening angle is dimensioned such that the access area is detected with the radiation.

[0027] By means of suitable beam shaping devices such as lenses and reflectors, the radiation emitted by the sensor unit is expanded so that the entire access area is covered by the radiation.

[0028] According to a second variant, the sensor unit is a scanning system such that its radiation is periodically guided within the access area.

[0029] In this case, bundled, preferably collimated radiation is deflected via a deflection unit so that it periodically sweeps over the access area.

[0030] In principle, the sensor unit can be formed by an ultrasonic sensor or the like. Particularly advantageously, the sensor unit is formed by an optical sensor or a radar sensor.

[0031] The sensor unit detects objects in the access area, particularly by determining their position. Object identification is also particularly advantageous, distinguishing safety-relevant objects such as people from non-hazardous objects such as transport vehicles or workpieces. This identification occurs, for example, by detecting specific object characteristics or movement patterns. During object detection, the current measured values of the sensor unit can be compared with reference values obtained during a teach-in process by measuring a fixed reference surface. This enables particularly reliable object detection.

[0032] In principle, the sensor unit can be activated during the entire operation of the safety device.

[0033] It is particularly advantageous that the sensor unit is only activated when the locking mechanism is not activated.

[0034] In particular, the sensor unit is only activated when the guard is in its open position and the access area is therefore clear.

[0035] According to a structurally advantageous embodiment, the sensor unit is an on-chip unit.

[0036] In this case, the sensor components of the sensor unit and an evaluation unit for evaluating sensor signals from the sensor components are integrated on a single chip. The evaluation unit can be a microprocessor.

[0037] The sensor unit designed in this way has a particularly small size and can be integrated in particular in the locking device.

[0038] Alternatively, the locking device and the sensor unit may form separate units, which are then connected via a suitable data connection for bidirectional data exchange.

[0039] According to an advantageous embodiment, an actuator can be provided which is attached to the separating protective device or is a component of the separating protective device.

[0040] A safety switch assigned to the actuator checks whether the actuator, and thus the guard, is in the closed position. For this purpose, the safety switch can be equipped with an RFID reader unit that can read data from a transponder in the actuator when the actuator is in its closed position on the safety switch.

[0041] If such a safety switch is used to protect a guard as access to a hazardous area on a system, operation of the system is only permitted when the safety switch detects that the actuator, and thus the guard to which the actuator is attached, is in its closed position. The safety switch then issues a corresponding switching signal.

[0042] With the safety switch as a switching signal, a release signal is only generated when the actuator is detected in a closed position.

[0043] The safety level of the safety device can be further increased by generating the release signal only when, as an additional condition, the locking is effected with the locking device and / or when the sensor unit detects that no safety-relevant object has entered the danger zone via the access area.

[0044] The locking device prevents uncontrolled opening of the guard. Locking the guard with the locking device thus represents an additional safety requirement to ensure that no safety-relevant object can gain uncontrolled access to the danger zone.

[0045] When the guard is open, the sensor unit determines whether and how many safety-relevant objects, especially people, are entering and exiting the danger zone. By determining the number of objects entering and exiting, it can be determined whether a safety-relevant object is still in the danger zone after the guard has closed, which could lead to a dangerous situation. Such dangerous situations can be avoided by using the sensor signals from the sensor unit as an additional condition for generating the release signal. This procedure can be extended to danger zones where multiple guards are provided. In this case, each guard is monitored with a separate sensor unit.A central evaluation unit then counts how many objects enter or leave the danger zone for each guard.

[0046] The sensor unit can also be used to perform a restart check of the system. In particular, the sensor unit can be used to implement a restart lock. For example, if the system has been shut down by the switching signal of the safety switch, restarting of the system is blocked as long as the sensor unit detects the intrusion of at least one safety-relevant object into the danger zone. Conversely, the sensor unit can be used to enable restarting of the system, namely when the sensor unit detects that no safety-relevant object has entered the danger zone for a specified period of time.

[0047] The invention is explained below with reference to the drawings. They show: Fig. 1: Schematic representation of an embodiment of the safety device according to the invention. Fig. 2: Illustration of the safety device according to Fig. 1 with a safety switch, an actuator and a sensor unit a) Actuator out of engagement position. b) Actuator in the engaged position on the safety switch when the guard locking mechanism is not actuated. c) Actuator in the engaged position on the safety switch with the guard locking actuated. Fig. 3: First example of a sensor unit for the safety device according to the invention. Fig. 4: Second example of a sensor unit for the safety device according to the invention.

[0048] Fig. Figure 1 schematically shows a safety device 1 for the safe operation of a system 2. The system 2 may pose hazards, particularly to persons. Accordingly, a danger zone 3 around the system 2 is secured by a fence 4. A protective door 5 is provided in the fence 4 as a separating protective device, through which persons can gain access to the danger zone 3.

[0049] System 2 is controlled by a safety controller 6. A safety switch 7 is provided as a component of safety device 1, which monitors whether the protective door 5 is closed or locked. The safety controller 6 controls the operation of system 2 based on the switching signals generated by the safety switch 7.

[0050] For this purpose, the safety switch 7 has an arrangement of safety outputs via which the switching signals are output to the safety controller 6. The term safety outputs also includes safe data connections such as PROFIsafe.

[0051] An actuator 8 is assigned to the safety switch 7.

[0052] The actuator 8 is also assigned a locking device 9, which in the present case is integrated in the safety switch 7, although this is not mandatory.

[0053] The safety switch 7 is stationary in a frame 4a that restricts access. The actuator 8 is located on the protective door 5 and is thus movable relative to the safety switch 7.

[0054] If the protective door 5 is in its closed position, it blocks access to the danger zone 3. The actuator 8 is then in the engagement range of the safety switch 7 and the locking device 9. The locking device 9 can then be used to hold the actuator 8 and thus the protective door 5 in the closed position, so that the protective door 5 is secured against unintentional opening.

[0055] The combination of the locking device 9 with the safety switch 7 is optional.

[0056] Fig. 1 shows the protective door 5 in an open position in which the protective door 5 allows access to the danger zone 3.

[0057] According to the invention, the safety device 1 has a sensor unit 10 with which an access area 3a to the danger area 3 is monitored.

[0058] In the present case, the sensor unit 10 is mounted on the horizontal part of the frame 4a, which forms the top of the frame 4a, so that the sensor unit 10 monitors the access area 3a from above. However, this is not mandatory. The sensor unit 10 can also be arranged on the vertical part of the frame 4a and, in particular, form a single unit with the safety switch 7.

[0059] The sensor unit 10 is connected via a Fig. 1 data connection not shown connected to the safety switch 7 and the locking device 9.

[0060] The Fig. 2a to 2c show the safety device 1 with the actuator 8 in different positions relative to the safety switch 7. The safety switch 7 has a housing 7a. A computer unit 11 is integrated therein, which is designed to generate the switching signals. The computer unit 11 is fail-safe and has a redundant structure for this purpose. An RFID reader 13 is arranged in the housing 7a of the safety switch 7, with which data can be read from a transponder 12 in the actuator 8 when the actuator 8 is within the reading range of the RFID reader 13. This is the case when the protective door 5 is in its closed position.

[0061] The safety switch 7 has an output 14 via which the switching signals generated in the computer unit 11 are output.

[0062] The safety switch 7 incorporates the locking device 9 with a locking element 15 in the form of a locking pin. The locking element 15 can be moved in the axial direction by means of an electric drive or the like (not shown). The electric drive is controlled by the computer unit 11.

[0063] Corresponding to the locking element 15, a recess 17 is provided in the actuator 8, which opens out on its underside.

[0064] The function of the safety switch arrangement designed in this way is explained below using the Fig. 2a to 2c explained.

[0065] When the protective door 5 is open, the actuator 8 is outside its engagement position on the actuator 8 ( Fig. 2a). The transponder 12 in the actuator 8 is then outside the reading range of the RFID reader 13.

[0066] When the protective door 5 is closed, the actuator 8 is in its engagement position on the safety switch 7 ( Fig. 2b). The transponder 12 is then located within the reading range of the RFID reading unit 13, so that data from the transponder 12 is read by the RFID reading unit 13 and evaluated, in particular decoded, in the computer unit 11.

[0067] Fig. 2c shows the actuator 8 in the engaged position when the locking is completed, ie the locking element 15 is extended upwards over the edge of the safety switch 7 and projects into the recess of the actuator 8 so that the latter is locked in the engaged position.

[0068] The Fig. 2a to 2c also show the sensor unit 10, which is connected to the computer unit 11 of the safety switch 7 via a data line 18 to form the data connection.

[0069] In general, the sensor unit 10 can also be integrated into the locking device 9 or the safety switch 7. This is particularly possible if the sensor unit 10 is an on-chip unit. In an on-chip unit, all components of the sensor unit 10 are integrated on one chip.

[0070] The sensor unit 10 is advantageously designed as an optical sensor or as a radar sensor.

[0071] The Fig. 3 and Fig. 4 show different embodiments of the sensor unit 10, wherein the Fig. 3 and Fig. 4 the sensor unit 10 in the mounting position according to Fig. 1, in which the access area 3a is monitored from above. In general, the sensor unit 10 is designed as a distance sensor with which the positions of objects in the access area 3a can be determined.

[0072] In both embodiments, the components of the sensor unit 10 are integrated in a sensor housing 10a. The sensor unit 10 comprises, as sensor components, a radiation-emitting transmitter unit 19 and a radiation-receiving receiver unit 20. Sensor signals generated in the receiver unit 20 are evaluated in an evaluation unit 21, which may be formed by a microprocessor or the like.

[0073] In the embodiment according to Fig. 3, beam-forming means 22, which may be in the form of lenses and / or reflectors, are assigned to the transmitting unit 19 and the receiving unit 20. The beam-forming means 22 generate radiation in the form of a beam cone 23 with a large aperture angle such that the entire access area 3a is illuminated. Fig. As shown in Figure 3, the radiation is directed toward a floor 24. The beam-shaping means 22 further ensure that reflected radiation is focused toward the receiver unit 20.

[0074] In the event that the sensor unit 10 is a radar sensor, the transmitter unit 19 is formed by a transmitting antenna and the receiver unit 20 by a receiving antenna.

[0075] If the sensor unit 10 is an optical sensor, the transmitter unit 19 can be an illumination unit and the receiver unit 20 can be a camera, i.e., an image sensor with a matrix arrangement of receiving elements. The distance measurements can be performed, in particular, using a pulse-time-of-flight method.

[0076] In the embodiment according to Fig.4, the sensor unit 10 is designed as a scanner. The transmitting unit emits a focused transmitting beam 25, which is periodically deflected by a deflection unit 26 and thus guided in the access area 3a.

[0077] If the sensor unit 10 is designed as a radar sensor, the transmitter unit 19 is again formed by a transmitting antenna and the receiver unit 20 by a receiving antenna.

[0078] If the sensor unit 10 is designed as an optical sensor, the transmitter unit 19 consists of a single transmitter such as a laser diode and the receiver unit 20 consists of a single receiver.

[0079] Distance values determined in the sensor unit 10 can be evaluated in its evaluation unit 21 itself or in the computer unit 11 of the safety switch 7 in order to identify objects, in particular safety-relevant objects as well as persons. In particular, safety-relevant objects can be differentiated from non-hazardous objects. For this purpose, object characteristics, movement profiles of objects, and the like are determined. In general, the floor 24 can also be taught as a reference surface, and the object detection can be referenced to this reference surface.

[0080] In the simplest case, an enable signal is generated in the computer unit 11 as a switching signal, with which the operation of the system 2 is enabled when it is recognized on the basis of the data read out by the transponder 12 by means of the RFID reading unit 13 that the protective door 5 is in the closed position.

[0081] As additional conditions for the generation of the release signal, it can be checked in the computer unit 11 whether the locking device 9 has caused the protective door 5 to be locked and / or whether the sensor unit 10 has determined that no safety-relevant object has entered the danger zone 3 through the access area 3a and remained there.

[0082] The sensor unit 10 detects whether and how many persons or generally safety-relevant objects enter the danger zone 3 via the access area 3a or exit the danger zone 3 via the access area 3a.

[0083] Thus, the sensor unit 10 generally fulfills a safety function that supplements the safety function of the locking device, so that an increased level of safety is achieved with the safety device 1.

[0084] In particular, the sensor unit 10 can be used to carry out a restart check of the system 2. List of reference symbols 1 safety device 2 Appendix 3 Danger zone 3a Access area 4 Fencing 4a frame 5 Protective door 6 Safety control 7 safety switches 8 actuators 9 Locking device 10 Sensor unit 10a Sensor housing 11 Computer unit 12 transponders 13 RFID reader unit 14 Exit 15 locking element 16 Storage 17 Recess 18 data line 19 Transmitter unit 20 Receiver unit 21 Evaluation unit 22 beam shaping agents 23 beam cones 24 Floor 25 transmit beam 26 Deflection unit

Claims

[1] Safety device (1) for securing access to a danger zone (3), with a separating protective device which can be moved between an open position and a closed position, wherein the separating protective device in its open position allows access to the danger zone (3) and wherein the separating protective device in its closed position blocks access to the danger zone (3), wherein the separating protective device is assigned a locking device with or without a guard locking device, characterized by wherein a sensor unit (10) is provided which is designed to monitor an access area (3a) to the danger area (3), characterized by that the locking device and the sensor unit (10) form a structural unit and / or that the locking device and the sensor unit (10) are connected via a data connection. [2] Safety device (1) according to claim 1, characterized bythat the sensor unit (10) is formed by an optical sensor or a radar sensor. [3] Safety device (1) according to one of claims 1 or 2, characterized by that the sensor unit (10) emits radiation at an opening angle, wherein the opening angle is dimensioned such that the access area (3a) is detected with the radiation. [4] Safety device (1) according to one of claims 1 or 2, characterized by that the sensor unit (10) is a scanning system such that its radiation is periodically guided within the access area (3a). [5] Safety device (1) according to one of claims 1 to 4, characterized by that the sensor unit (10) is a distance sensor by means of which positions of objects in the access area (3a) can be determined. [6] Safety device (1) according to one of claims 1 to 5, characterized bythat safety-relevant objects can be detected and identified by means of the sensor unit (10). [7] Safety device (1) according to one of claims 1 to 6, characterized by that the sensor unit (10) is an on-chip unit. [8] Safety device (1) according to one of claims 1 to 7, characterized by that the locking device is formed by a safety module with or without a locking device (9). [9] Safety device (1) according to claim 8, characterized by that the safety module is a safety switch (7). [10] Safety device (1) according to one of claims 8 or 9, characterized by that the locking device (9) is arranged in or on the safety module. [11] Safety device (1) according to one of claims 1 to 10, characterized bythat an actuator (8) is present as a component of the separating protective device or on the separating protective device, wherein in the closed position of the separating protective device the actuator (8) can be locked with the locking device (9). [12] Safety device (1) according to claim 11, characterized by that a transponder (12) is present in the actuator (8), and that an RFID reading unit (13) is present in the safety switch (7), by means of which data can be read from the transponder (12) when the actuator (8) is in the closed position. [13] Safety device (1) according to one of claims 9 to 12, characterized by that a switching signal is generated in the safety switch (7), by means of which a system (2) in or near the danger zone (3) is controlled. [14] Safety device (1) according to claim 13, characterized bythat with the safety switch (7) as a switching signal, a release signal is only generated when the actuator (8) is detected in its closed position. [15] Safety device (1) according to claim 14, characterized by that the release signal is only generated if, as an additional condition, the locking is effected with the locking device (9) and / or if the sensor unit (10) determines that no safety-relevant object has entered the danger zone (3) via the access area (3a). [16] Safety device (1) according to one of claims 13 to 15, characterized by that a restart of the system (2) is controlled depending on sensor signals from the sensor unit (10). [17] Method for operating a safety device (1) for securing access to a danger zone (3), comprising a separating protective device which can be moved between an open position and a closed position, wherein the separating protective device in its open position allows access to the danger zone (3) and wherein the separating protective device in its closed position blocks access to the danger zone (3), wherein a locking device with or without a guard locking mechanism is assigned to the separating protective device, characterized by wherein a sensor unit (10) is provided which is designed to monitor an access area (3a) to the danger area (3), characterized by that the locking device and the sensor unit (10) form a structural unit and / or that the locking device and the sensor unit (10) are connected via a data connection.

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