Safety door monitoring module

Abstract

Safety door monitoring module (16) for monitoring the state of a safety door (14), comprising a basic unit (34) for generating a safety door signal and an actuator (36) movable relative to the basic unit (34) for actuating the basic unit (34), wherein the basic unit (34) has an actuator receptacle (38) for receiving the actuator (36) and is configured to generate the safety door signal when the actuator (36) is inserted into the actuator receptacle (38), characterized in that the actuator (36) has at least a defined electrical resistance (42) and the basic unit (34) is configured to detect the defined electrical resistance (42) of the actuator (36), to recognize the presence of the actuator (36) in the actuator receptacle (38) based on the measured resistance and to generate the safety door signal depending on its presence.

Description

[0001] The present invention relates to a safety door monitoring module for monitoring the state of a safety door, comprising a basic unit for generating a safety door signal and an actuator movable relative to the basic unit for actuating the basic unit, wherein the basic unit has an actuator receptacle for receiving the actuator and is configured to generate the safety door signal when the actuator is inserted into the actuator receptacle.

[0002] Safety door monitoring modules of the aforementioned type are also frequently referred to as safety switches. A safety door monitoring module or safety switch of the type mentioned above is known from DE 10 2005 057 108 A1. Further exemplary safety door monitoring modules are known from DE 103 05 704 B3, DE 10 2008 060 004 A1 and DE 10 2020 120 817 A1.

[0003] Standard safety door monitoring modules are used on safety doors, safety flaps, sliding doors, and the like. Although the terms "safety door monitoring module" and "safety door" are used here, the safety door monitoring module according to the invention can be used on any type of separating safety device. The term "safety door" is to be understood broadly in this context. Therefore, instead of the general term "separating safety device," only the term "safety door" will be used in the following, without this implying any limitation of the protected area.

[0004] Safety doors, on which, for example, the safety door monitoring module according to the invention can be installed, typically serve as access to a safety area containing an automated machine or system. The machine may be, for example, a robot, a machine tool with a high-speed rotating spindle, a transport or conveyor system, a press, or another machine or system whose operation poses a danger to persons located in the aforementioned safety area or in the machine's working area. The safety door monitoring module can serve as a signaling device that enables a control system to detect the closed state of the safety door. The control system is configured to read the safety door signal generated by the safety door monitoring module and to control the machine based on this signal.For example, the machine can only operate if the safety door signal is present. In other words, the control system is configured to only allow the machine or system to operate when it receives the safety door signal from the safety door monitoring module, i.e., when the safety door is closed. If, on the other hand, the safety door is opened during operation (if possible), the control system must bring the machine or system to a safe state, for example, by cutting off the power supply.

[0005] Safety door monitoring modules of this type typically consist of an actuator and an actuator receptacle. The actuator receptacle is part of a base unit, which typically houses other electronic components and from which the connecting cables usually extend, linking the safety door monitoring module to the control unit. Accordingly, the base unit with the actuator receptacle is preferably mounted on a fixed part of the safety door (e.g., a door frame), while the actuator is preferably mounted on a moving part of the safety door (e.g., a movable door leaf). This has the advantage that the part of the safety door monitoring module mounted on the moving part of the safety door does not require a power supply, as typically only the base unit of the safety door monitoring module needs power.

[0006] When the safety door closes, the actuator engages in the actuator receptacle, which is detected by one or more sensors. As shown, for example, in DE 10 2005 057 108 A1, the detection of the actuator in the actuator receptacle can be based on magnetic or radio-based (RFID, etc.) technologies. While these technologies are widespread and effective, they have their limitations, particularly in environments where they are susceptible to interference or tampering.

[0007] DE 10 2008 055 685 A1 describes a device for monitoring the state of a machine's protective device, in particular a safety switch for detecting and maintaining the closed state of a safety door. The device comprises an actuator and a switch head with an integrated locking mechanism, as well as a sensor element that enables the detection of a so-called "first position" of the actuator—a position in which the door is closed but not yet locked. This allows for reliable state monitoring without immediately activating the locking mechanism. This solution makes it possible to close several safety doors independently and signal their individual states before central or manual activation of the locking mechanism. Position detection is achieved by a change in the force acting on the sensor element, which is detected, for example, via piezoresistive or capacitive effects.

[0008] Against this background, it is a task to provide a safety door monitoring module that is more flexible in detecting the actuator in the actuator receptacle, minimizes susceptibility to interference and can ensure effective protection against manipulation.

[0009] This task is solved, starting from a safety door monitoring module of the type mentioned above, by the fact that the actuator has at least a defined electrical resistance and the basic unit is configured to detect the defined electrical resistance of the actuator, to recognize the presence of the actuator in the actuator receptacle based on the measured resistance, and to generate the safety door signal depending on its presence.

[0010] Therefore, one idea is to identify the actuator in the actuator housing via a defined electrical resistance of the actuator. In contrast to known detection methods, such a concept offers several advantages.

[0011] The use of a defined electrical resistance in the actuator enables highly accurate and reliable detection, independent of external interference that can affect magnetic or radio-based detection methods. This method is not only more resistant to environmental influences such as dust, moisture, or electromagnetic fields, but also allows for cost-effective manufacturing and easy maintenance.

[0012] The resistor can, for example, be implemented as a simple passive component that does not require its own power supply. This simplifies the design and increases operational reliability, as fewer components can fail. The resistance can be measured by a simple electronic circuit within the main unit, which measures the resistance value of the defined electrical resistance and checks whether it corresponds to a predefined target value.

[0013] Such a safety door monitoring module can be particularly advantageous in industrial environments where high demands are placed on the reliability and safety of monitoring systems. By using electrical resistance as the detection mechanism, the system is especially suitable for areas where other technologies could be disrupted by external influences.

[0014] In addition to implementing resistance as a safety feature, this technology also offers the possibility of signaling different states or modes of the safety door by varying the resistance value. This could be further developed into condition monitoring or diagnostic systems that enable detailed monitoring of the safety door's condition.

[0015] Furthermore, such a safety door module can be easily integrated into existing safety door monitoring systems without requiring major modifications to the mechanical hardware. Adapting existing modules to the new detection method requires only minimal modifications, facilitating its use in a wide range of industrial applications.

[0016] Using a defined electrical resistance to detect an actuator in an actuator receptacle enables the monitoring of safety doors, offering higher reliability and safety than conventional methods while being cost-effective and easy to implement. The aforementioned task is therefore completely solved.

[0017] According to a further embodiment, the actuator can have an integrated electrical component that determines the defined electrical resistance of the actuator.

[0018] This design offers the following advantages: First, it increases the accuracy of the resistance values, as the component can be specifically designed and optimized for this purpose. Second, it improves the system's reliability because the component is integrated directly into the actuator and is therefore less susceptible to external damage or tampering. Third, integration allows for miniaturization of the actuator, making it less bulky and easier to integrate into various safety door designs. Fourth, using an integrated component can standardize and simplify production, leading to manufacturing cost savings. Fifth, it offers the possibility of integrating additional functionalities such as temperature measurement or monitoring of other environmental conditions, thus expanding the monitoring capabilities of the safety door module.

[0019] According to a further embodiment, the electrical component can be integrated into an actuator element that can be inserted into the actuator receptacle and be electrically isolated from the actuator element.

[0020] Integrating an electrically isolated component into the actuator improves the reliability and effectiveness of the detection mechanism. The isolation protects the component from external electrical interference, ensuring trouble-free operation and facilitating precise reading of the defined electrical resistance. This design not only increases the accuracy of the resistance measurement but also enables fast and accurate detection of the actuator's state. Furthermore, it minimizes the risk of misinterpretations and signal loss.

[0021] According to a further embodiment, the electrical component can be an SMD resistor or a wire-wound resistor.

[0022] The use of SMD resistors and leaded resistors allows for the precise setting of a defined electrical resistance. SMD resistors, with their compact and space-saving design, also make it possible to equip even small actuators with a defined electrical resistance. For example, an SMD resistor can be easily inserted into a bore or recess of the actuator without altering its external shape. Leaded resistors, on the other hand, are characterized by their high power handling capacity and are particularly easy to maintain and replace due to their improved accessibility. This flexibility in the choice of resistor type allows for effective adaptation to different operating conditions and increases the reliability of the safety door monitoring system.

[0023] According to a further embodiment, the actuator can have at least one electrical contact via which the actuator can be connected to a measuring circuit in the basic device when the actuator is inserted into the actuator receptacle.

[0024] This direct electrical connection offers several advantages: It ensures high measurement accuracy and reliability when recording the defined electrical resistance, as interference from contact resistance or environmental influences is minimized. Furthermore, this approach facilitates the quick and error-free reading of the measured values, leading to more efficient monitoring and faster response times from the safety door monitoring module. This design also increases the overall system safety by ensuring that a safety door signal is only generated when the actuator is in the correct position, thus preventing unintended operating states.

[0025] According to a further embodiment, the electrical contact can be designed as a contact spring or as a pressure piece.

[0026] A contact spring enables a flexible and durable connection that remains stable even under mechanical stress from vibrations or frequent actuation. This ensures constant electrical conductivity and prevents interruptions in the signal flow. A pressure piece, on the other hand, offers the advantage of ensuring a secure and firm contact under pressure, which is particularly beneficial in environments with high demands on physical robustness. Both designs contribute to increasing the efficiency and safety of the safety door monitoring module by ensuring a reliable and responsive connection within the system.

[0027] According to a further embodiment, the basic device can be configured to detect the defined electrical resistance by means of a voltage measurement and to recognize the presence of the actuator in the actuator receptacle by comparing a measured voltage value with an expected voltage value. In particular, the basic device can be configured to distinguish, based on the voltage measurement, between a first state in which the actuator is not inserted into the actuator receptacle, a second state in which the actuator is inserted into the actuator receptacle, and a third state in which something other than the actuator is inserted into the actuator receptacle.

[0028] In other words, the base unit measures the voltage across the actuator and compares this measured voltage value with a predefined expected voltage value. This method enables accurate and reliable detection of the actuator's presence in the actuator receptacle, thus allowing for precise condition monitoring. This type of measurement makes it possible to detect even the slightest changes in resistance, which is particularly important in safety-critical applications where the actuator must be detected with high reliability. Furthermore, various states can be detected, thereby expanding the range of functions and, in particular, enabling diagnostic capabilities.

[0029] According to a further embodiment, the actuator can have at least one further defined electrical resistance and the basic device can be configured to recognize a defined position of the actuator in the actuator receptacle based on the defined electrical resistance and the further defined electrical resistance, and to generate the safety door signal depending on the recognized position.

[0030] By measuring and comparing multiple resistance values, the base unit can detect not only the presence but also the precise position of the actuator. This capability allows for a differentiated assessment of the actuator's position, enabling it to determine not only whether the actuator is inserted into the receptacle but also whether it is correctly oriented. This design thus opens up further application possibilities for the safety door module beyond simple status detection. Furthermore, this design enhances tamper protection.

[0031] According to a further embodiment, the actuator receptacle can have a mechanical shape that interacts with a corresponding shape of the actuator to ensure precise mechanical positioning and electrical contacting of the actuator.

[0032] In this design, the actuator receptacle features a special mechanical shape that interacts with a corresponding shape on the actuator. This precisely engineered interaction between the receptacle and the actuator enables exact mechanical positioning of the actuator within the receptacle. This ensures not only that the actuator is correctly aligned, but also that the electrical contacts for measuring the defined electrical resistance are reliably connected. The precise positioning improves the consistency and reliability of the resistance measurement, which is essential for the error-free operation of the monitoring system. This targeted mechanical and electrical integration promotes optimal performance of the safety door monitoring module and minimizes the risk of malfunctions due to incorrect actuator positioning.

[0033] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or on their own, without leaving the scope of the present invention.

[0034] Exemplary embodiments of the invention are shown in the drawing and are explained in more detail in the following description. They show: Fig. 1 a schematic representation of a safety door monitoring system according to an embodiment of the present invention; Fig. 2 a perspective view of a safety door monitoring module according to an embodiment of the present invention in an open position; Fig. 3 a perspective view of the in Fig. 2 safety door monitoring module shown in a closed position; Fig. 4A a schematic view of an actuator according to a first embodiment of the present invention; Fig. 4B a top view of the actuator according to Fig. 4A; Fig. 4C a cross-section along line II' from Fig. 4B; Fig. 4D an enlarged view of section A from Fig. 4C; Fig. 5 a schematic view of an actuator inserted into the actuator receptacle; Fig. 6 a schematic representation of a measuring circuit according to an embodiment of the present invention; Fig. 7 a schematic cross-sectional view of a first variant for embedding the defined electrical resistance in the actuating element; Fig. 8 a schematic cross-sectional view of a second variant for embedding the defined electrical resistance in the actuating element; Fig. 9 a schematic cross-sectional view of a third variant for embedding the defined electrical resistance in the actuating element; and Fig. 10A a schematic view of an actuator according to a second embodiment of the present invention; Fig. 10B a top view of the actuator according to Fig. 10A; Fig. 10C a cross-section along line II-II' from Fig. 10B; and Fig. 10D an enlarged view of section B from Fig. 10C.

[0035] Fig. Figure 1 shows a schematic view of an embodiment of a safety door monitoring system according to the invention. The safety door monitoring system is referred to collectively by the reference numeral 10.

[0036] The safety door monitoring system 10 comprises a robot 12 whose workspace is secured by a safety door 14. A safety door monitoring module 16 according to the present invention is arranged on the safety door 14. The safety door monitoring module 16 comprises a door part 17, which is arranged on the movable door element (door leaf) of the safety door 14, and a frame part 18, which is arranged on a fixed static part 20 of the safety door. In the illustrated embodiment, the fixed static part 20 of the safety door 14 is a door frame or a door jamb. In other embodiments, this fixed static part 20 of the safety door 14 can also be a second door leaf of a two-part safety door.

[0037] The frame part 18 is connected to a safety switching device 26 via two lines 22, 24. The safety switching device 26 is, for example, a safety switching device of the PNOZ© series, which is marketed by the applicant of the present invention. This is a multi-channel redundant safety switching device designed to evaluate the output signals of signaling devices, such as the safety door monitoring module 16, and to disconnect an electrical load accordingly. In this case, the electrical load is the robot 12. The safety switching device 26 therefore controls two contactors 28, 30, whose normally open contacts are located in the connection between a power supply 32 and the robot 12.As an alternative to the safety switching device 26, the safety door monitoring module 16 could also be connected to a programmable safety controller, such as the one marketed by the applicant of the present invention under the designation PSS©. The safety switching device 26 is therefore referred to below generally as the controller of the safety door monitoring system 10, without this being limited to a specific configuration of this controller. Several exemplary embodiments of the safety door monitoring module 16 according to the invention are described below. Identical or equivalent components are designated with the same reference numerals.

[0038] Fig. 2 and Fig. Figure 3 shows a first embodiment of the safety door monitoring module 16, each in a perspective view. Fig. Figure 2 shows the safety door monitoring module 16 in an open position of the safety door 14. Fig. Figure 3 shows the safety door monitoring module 16 in a closed position of the safety door 14.

[0039] The safety door monitoring module 16 comprises a base unit 34. The base unit 34 preferably has one or more sensors and / or other electronic components and is therefore preferably connected to a power supply. Furthermore, the base unit 34 is preferably connected to the control unit 26 via multi-channel redundant lines, such as lines 22 and 24 in this case. The base unit 34 thus preferably forms the aforementioned frame part 18 of the safety door monitoring module 16.

[0040] Although it would also be conceivable to use the basic unit 34 as the door part 17 of the safety door monitoring module 16, this is less preferred. In this case, the usually fixed wiring to the control unit 26 and the power supply would have to be routed to the moving part of the safety door 14, which is generally more complex than routing the lines 22, 24 and the power supply to the static part 20 of the safety door 14.

[0041] The safety door monitoring module 16 also includes an actuator 36. This actuator 36 acts as a counterpart to the base unit 34 and serves to actuate the base unit 34. The base unit 34 has a corresponding actuator receptacle 38 into which the actuator 36 can be inserted (see Fig. 3).

[0042] One function of the basic unit 34 is to detect whether the actuator 36 is inserted into the actuator receptacle 38 or not. The basic unit 34 is configured to generate a safety door signal when the actuator 36 is inserted into the actuator receptacle 38. This safety door signal is preferably an electrical signal. It can be a digital signal, a pulsed signal, a coded signal, and / or another (preferably electrical) signal. By evaluating the safety door signal in the controller 26, the safety door monitoring system 10 can unambiguously determine at any time whether the safety door 14 is closed or not. Depending on this, the robot 12 can be controlled such that it can only be operated when the safety door 14 is closed.

[0043] The actuator 36 of the safety door monitoring module 16 has a substantially ring-shaped actuating element 40 that can be inserted into the actuator receptacle 38. As shown in Fig. As shown in Figure 3, the essentially ring-shaped actuator element 40 is inserted into the actuator receptacle 38 when the safety door 14 is closed. Due to its ring shape, the actuator element 40 can be inserted into the actuator receptacle 38 relatively easily and from various sides. This allows for even the smallest pivot radii, such as those encountered with small flaps or very small safety doors. Because of its shape, the actuator element 40 poses virtually no risk of injury, as it has no sharp or angular geometries.

[0044] Of course, the present invention is not limited to a substantially ring-shaped actuator element 40. Oval or rectangular bodies are also conceivable as actuator elements 40. Likewise, a through-opening in the actuator element 40 is not strictly necessary. In a further embodiment, the actuator element 40 can also have a closed shape. In this case, the actuator element 40 can, for example, have a recess into which a locking element in the actuator receptacle 38 engages to fix the actuator in a specific position. However, the following description continues to refer to an actuator 36 with a substantially ring-shaped actuator element 40.

[0045] Fig. Figure 4A shows a schematic view of an actuator 36 according to an embodiment of the present invention. Fig. Figure 4B shows a top view of the actuator according to Fig. 4A, Fig. 4C a cross-section along line II' from Fig. 4B and Fig. 4D an enlarged view of section A from Fig. 4C. In Fig. 4A, Fig. 4B, Fig. 4C and Fig. Figure 4D essentially depicts the actuator element 40, which can be inserted into the actuator receptacle 38. The actuator 36 is characterized by a defined electrical resistance 42, which is integrated into the actuator element 40. The defined electrical resistance 42 is shown here only schematically and can be integrated into the actuator element 40 in various ways, as will be explained in more detail below. The invention is not limited to a specific mechanical or electrical integration, provided that it is possible to determine the defined electrical resistance 42 and to ascertain a property inherent in the defined electrical resistance 42, in particular an electrical resistance value.

[0046] An electrical resistor 42, regardless of its physical form, has two terminals 44, 46 through which the resistor can be electrically connected. In the embodiment shown here, the two terminals 44, 46 are each brought to the outside via two contacts 48, 50 on a surface 52 of the actuator 40. The defined electrical resistor 42 can be connected to an electrical circuit via the contacts 48, 50 when the actuator 40 is inserted into the actuator receptacle 38 and is in contact with corresponding contact partners. The contacts 48, 50 can be arranged such that they are only in contact with the corresponding contact partners when the actuator 40 is inserted into the actuator receptacle 38 in a defined manner.

[0047] Contacts 48 and 50 can, as in Fig. As schematically indicated in Figure 4B, the contacts 48 and 50 are aligned in opposite directions of an axis. For example, if the resistor 42 is integrated into a through-hole 54 in the actuator 40, the inlet and outlet openings of the bore can each have contacts 48 and 50, respectively. This configuration is advantageous if the actuator receptacle 38 encloses the actuator 40 in a pincer-like manner and can contact the resistor 42 from opposite sides. In principle, the contacts 48 and 50 can also be brought out in another way if a different type of contact through the actuator receptacle 38 is advantageous. Likewise, in another embodiment, only one contact can be brought out. This can be the case if the electrical circuit with which the resistance is to be detected can be connected in another way to a potential that is also available within the actuator (e.g.,...).a common ground connection of actuator 36 and actuator receptacle 38).

[0048] Fig. Figure 5 shows a schematic view of an actuator 36 inserted into the actuator receptacle 38. The actuator receptacle 38 and the actuator element 40 are indicated in cross-section. In the illustration, the actuator element 40 is fully inserted into the actuator receptacle 38. A retaining element 56 engages behind the actuator element 40 and holds the actuator 36 in a closed position. In the closed position, the contacts 48, 50, as described above, contact at least one contact partner (here a first and a second mating contact 58, 60) in the actuator receptacle 38. The defined electrical resistance 42 can be connected to a measuring circuit 62 via the connection between the mating contacts 58, 60 and the contacts 48, 50 of the actuator element 40.

[0049] The measuring circuit 62 makes it possible to detect the resistance 42 and determine its magnitude, as described below with reference to Fig. This is explained in more detail in section 6. The measuring circuit 62 is in turn connected to an evaluation unit 64 of the base unit 34, which generates the safety door signal. The evaluation unit 64 is configured such that it generates the safety door signal only if the defined electrical resistance 42 has been detected by the measuring circuit 62 and it can be assumed that the actuator 36 is in the closed position. If the measuring circuit 62 does not detect the defined electrical resistance 42 or if it detects a resistance value that does not correspond to a predefined value, the evaluation unit 64 does not generate the safety door signal. Thus, the base unit 34 can detect not only whether an actuator 36 is inserted into the actuator receptacle 38, but also whether it is the correct actuator 36.

[0050] Fig. Figure 6 shows a schematic representation of a measuring circuit according to an embodiment of the present invention.

[0051] The measuring circuit 62 is equipped with a measuring resistor 66 and has a first and a second potential connection 68, 70, as well as a measuring connection 72. A supply voltage, typically a 24 V potential used in industrial applications, can be applied to the measuring circuit 62 via the first potential connection 68. This potential is applied to the first mating contact 58 of the actuator receptacle 38. The second potential connection 70, which accepts a potential different from the first potential, for example, a ground potential, is connected to the second mating contact 60 of the actuator receptacle 38, with the measuring resistor 66 being arranged between the second potential connection 70 and the second mating contact 60. Furthermore, the measuring connection 72 is arranged between the measuring resistor 66 and the second mating contact 60, via which the measuring circuit 62 can be connected to the evaluation unit 64.

[0052] When the actuator 36 is inserted into the actuator receptacle 38 as described above, and the first and second contacts 48, 50 are each connected to their corresponding mating contacts 58, 60, the measuring resistor 66 and the defined electrical resistance 42 of the actuator 36 are connected in series between the first potential terminal 68 and the second potential terminal 70. In this state, the measuring circuit 62 corresponds to a conventional voltage divider circuit. From the voltage applied to the measuring terminal 72, the known magnitude of the potential difference between the first and second potential terminals 68, 70, and the magnitude of the measuring resistor 66, the magnitude of the defined electrical resistance 42 can be directly calculated.By comparing the voltage measured at the measuring terminal 72 with a specified voltage range, it can be determined whether the defined electrical resistance 42 corresponds to a specified resistance value within a specified tolerance range.

[0053] In one embodiment, the measuring terminal 72 can, for example, be connected to an input of an analog-to-digital converter (ADC) that converts the measured voltage into a discrete range of values. The analog-to-digital converter can be part of a microcontroller functioning as an evaluation unit 64, which processes the converted values ​​and decides whether the resistance applied to the mating contacts 58, 60 corresponds to the expected resistance. In this way, the basic unit 34 can decide whether the actuator 36 inserted into the actuator receptacle 38 corresponds to an actuator 36 that can be assigned to the defined electrical resistance 42, and only generate a safety door signal if the actuator 36 corresponds to the expected actuator 36.

[0054] In the measuring circuit 62 according to Fig. Figure 6 shows an additional series resistor 74. This is arranged between the first potential terminal 68 and the first opposite contact 58. The series resistor 74 allows the voltage range that can be applied to the measuring terminal 72 to be set within a specific range relative to the potential applied to the first potential terminal 68. For example, if a microcontroller connected to the measuring terminal 72 has an input range between 0V and 5V, the series resistor 74 can limit the operating voltage of 24V applied to the first potential terminal 68 to a maximum of 5V at the measuring terminal 72.

[0055] In relation to Fig. In Figure 6, a measuring circuit 62 based on a voltage divider was shown to implement a simple and cost-effective measuring circuit. However, other measuring circuits are also conceivable, for example, a Wheatstone bridge, if a more precise measurement of the defined electrical resistance 42 is required for the application. Measuring circuits for resistance measurement are well known, and the invention is not limited to a specific type of measuring circuit.

[0056] With reference to the Fig. 7, Fig. 8 and Fig. 9 Various examples of a mechanical embedding of the defined electrical resistance in the actuating element 40 are shown below.

[0057] Fig. Figure 7 shows a schematic cross-sectional view of a first variant for embedding the defined electrical resistance in the actuator element 40. In the variant shown, a through-hole 54 is provided in the actuator element 40, into which the defined electrical resistance 42 is embedded. In particular, an insulating housing 76, for example in the form of a plastic tube / sleeve, is inserted into the through-hole 54. The housing 76 electrically insulates the components inserted into the housing from the actuator element 40. By means of an annular housing support 78 on one or both opening sides of the through-hole 54, the housing 76 can be snapped into the through-hole 54.

[0058] The defined electrical resistor 42 is embedded in the housing 76, for example as a passive electrical component. In a preferred embodiment, the electrical component can be cast into a receiving element 80 within the housing 76 ("hot melt"), thereby mechanically holding it in a specific position within the housing 76.

[0059] The defined electrical resistance 42 can be contacted via at least one contact 48, 50 above and / or below the receiving element 80 within an opening of the through-hole 54. Preferably, the defined electrical resistance 42 can be contacted from both sides of the opening of the through-hole 54. Contact can be made by a resilient contact element 82, for example, by a "knee-type contact ring." A "knee-type contact ring" is a specific mechanical component used in mechanical systems to support movable connections while simultaneously ensuring an electrical connection. In this context, the term "knee" typically refers to an angled, "knee-shaped" resilient contact tab that allows for a specific movement or adjustment in the mechanics of the system.This design can be used to ensure that the electrical connection is maintained even during movement or under load. The contact ring itself serves as a conductive element that maintains the electrical connection between two parts of a system, here the defined electrical resistance 42 and the mating contact in the actuator receptacle, while the "knee" provides additional mechanical flexibility.

[0060] Fig. Figure 8 shows another variant of the mechanical embedding of the electrical resistance in the actuating element. Fig. Figure 8 is also a schematic cross-sectional view through the actuator element 40. As before, the electrical resistor 42 and the contact are arranged in a housing 78, which is inserted into a through-hole 54 of the actuator element 40.

[0061] The variant according to Fig. 8 differs from the variant according to Fig. 7 by a simplified design of the spring contact element 82. These are latched here via sword geometries 84 in receiving pockets 86 on the housing 78. The contacting of the spring contact element 82 with the defined resistance 42 can be effected, for example, via simple sliding contacts.

[0062] Fig. Figure 9 shows another variant of the mechanical embedding of the electrical resistor in the actuator element using pressure pieces as contact elements. As before, the actuator element 40 is provided with a plastic housing 78 that mechanically holds the electrical resistor 42 and electrically insulates it from the actuator element 40. This housing 78 is again positioned in a through-hole 54 of the actuator element 40, as in the previous variants.

[0063] The contact between the defined electrical resistance 42 and the measuring circuit 62 is made via pressure pieces 88, which enable a special mechanical and electrical connection. The pressure pieces 88 have spring-loaded balls 92 embedded in a sleeve 90 to ensure a constant contact normal force. This allows the pressure pieces 88 to exert a uniform and continuous force on the contact surfaces of the mating contacts, resulting in improved and more reliable contact.

[0064] Within the housing 78, the defined electrical resistance 42 can be located in a recess 94, and contact with the pressure pieces 65 can be made at contact points 96 on the outside of the pressure pieces 88. The design with pressure pieces 88 has the advantage that the pressure pieces 88 are available as standard parts, which simplifies manufacturing and assembly and can potentially reduce costs.

[0065] Fig. Figure 10 shows a schematic view of an actuator according to a second embodiment of the present invention. Fig. Figure 10B shows a top view of the actuator according to Fig. 10A, Fig. 10C a cross-section along line II-II' from Fig. 10B and Fig. 10D an enlarged view of section B from Fig. 10C.

[0066] The views of Fig. 10A, Fig. 10B, Fig. 10C and Fig. Figure 10D shows an actuator 36, which is essentially an actuator 36 according to the views of Fig. 4A, Fig. 4B, Fig. 4C and Fig. 4D corresponds. As in the first embodiment, the actuator 36 according to the second embodiment also has a through-hole 54 in which an electrical resistor is embedded (not shown in detail here). In contrast to the actuator 36 according to the first embodiment, however, a further through-hole 97 is provided in the actuator element 40, in which a further electrical resistor 98 is embedded and provided with corresponding contacts 100, 102. The further resistor 98 can be contacted via the contacts 100, 102 in the same way as the resistor 42 can be contacted via the contacts 48, 50 ( Fig. 4D). The contacts 100, 102 of the further resistor 98 are provided at a different location on the actuator element 40 than the contacts 48, 50 of the resistor 42.

[0067] The actuator can have corresponding mating contacts to contacts 100 and 102 of the additional resistor 98, so that, analogous to the detection of resistor 42, the presence of the additional resistor 98 can also be determined. Only if both resistor 42 and the additional resistor 98 are correctly detected does the basic unit generate the safety door signal. In this way, tamper protection can be further increased, as manipulation would then only be possible with disproportionately high effort. It is also conceivable that the additional resistor 98 has a different value than resistor 42, which would further enhance tamper protection.

[0068] Furthermore, measuring the additional resistance 98 allows for a more precise determination of the position and / or orientation of the actuator element 40 relative to the actuator receptacle 38, since several contact points must be aligned. The use of electrically contactable resistors is particularly advantageous here compared to a similar design based on magnets or radio signals, as mutual interference between the components can be ruled out.

[0069] The views according to the Fig. 10A, Fig. 10B, Fig. 10C and Fig. Figure 10D thus demonstrates an approach which, through an additional integrated resistor 98, not only increases safety but also improves the accuracy of the position detection of the actuator 40. The additional resistor 98 is embedded at a different location within the actuator 40 and is provided with its own contacts 100, 102. This arrangement enables independent and simultaneous contacting of both resistors, thereby increasing the detection accuracy and thus the reliability of the overall system.

[0070] The differentiated contacting of the two resistors 42 and 98 via different contact points on the actuator element 40 and corresponding mating contacts in the actuator receptacle 38 significantly increases tamper protection. This is because tampering would now require a technically more sophisticated and therefore less likely simultaneous bridging or simulation of both resistors. Furthermore, selecting different resistance values ​​for resistors 42 and 98 allows for an even higher level of security, as the specific resistance values ​​for activating the safety door signal must be precisely coordinated and detected.

[0071] This more sophisticated configuration results in an improved safety architecture for the safety door monitoring module, enabling precise monitoring not only of the presence but also of the exact position of the actuator element 40. By simultaneously detecting both resistors, the system gains an additional monitoring dimension by ensuring that both resistors are correctly and completely inserted into the actuator receptacle before operation, e.g., of a robot 12 (as in Fig. 1) is released. This significantly contributes to increasing operational safety and minimizes the risk of malfunctions or unauthorized access to secured areas.

[0072] Alternatively, instead of an additional resistor, an additional magnetic and / or radio-based sensing device could be integrated into the actuator. This would allow the use of two different technologies for condition monitoring, which could be evaluated complementarily. This added diversity would further enhance the reliability of the condition monitoring.

[0073] The exemplary embodiments of the safety door monitoring module shown in the figures serve solely to illustrate specific aspects and possibilities of the present invention. It should be emphasized that these examples represent only illustrative implementations and are in no way intended to limit the variety of possible embodiments. The various features and variants shown can be applied in numerous combinations and modifications, depending on the specific requirements and technical conditions of the application areas.

[0074] The flexibility in the design and implementation of these features allows for broad adaptability and optimization of the invention for different operating conditions and scenarios. The scope of protection of the present invention is therefore not limited to the examples shown, but is defined exclusively by the claims formulated below. These patent claims establish the legal limits within which protection is granted and thus determine precisely what is protected by the patent. Any variations falling within these claims are therefore to be considered as encompassed by the invention, regardless of whether they are designed exactly like the examples shown or not. Reference symbol list 10 Safety door monitoring system 12 robots 14 Protective door 16 Safety door monitoring module 18 frame parts 20 static part of the safety door 22, 24 Management 26 Safety switching device (control unit) 28, 30 Schütz 32 Power supply 34 Basic unit 36 actuators 38 Actuator mounting 40 Actuating element 42 electrical resistance 48 first contact 50 second contact 52 surface 54 Through hole 56 Holding element 58 first contact 60 second contact 62 Measuring circuit 64 evaluation units 66 Measuring resistor 68 first potential connection 70 second potential connection 72 Measuring connection 74 Series resistor 76 Enclosures 78 Housing support 80 recording element 82 spring-loaded contact element 84 sword geometries 86 Recording bag 88 printed piece 90 Sleeve 92 balls 94 recess 96 Contact point 98 electrical resistance 100 contacts 102 Contact

Claims

[1] Safety door monitoring module (16) for monitoring the state of a safety door (14), comprising a basic unit (34) for generating a safety door signal and an actuator (36) movable relative to the basic unit (34) for actuating the basic unit (34), wherein the basic unit (34) has an actuator receptacle (38) for receiving the actuator (36) and is configured to generate the safety door signal when the actuator (36) is inserted into the actuator receptacle (38), characterized by , that the actuator (36) has at least a defined electrical resistance (42) and the basic unit (34) is designed to detect the defined electrical resistance (42) of the actuator (36), to recognize the presence of the actuator (36) in the actuator receptacle (38) based on the measured resistance and to generate the safety door signal depending on its presence. [2] Safety door monitoring module according to claim 1, wherein the actuator (36) has an integrated electrical component that determines the defined electrical resistance (42) of the actuator (36). [3] Safety door monitoring module according to claim 2, wherein the electrical component is integrated in an actuating element (40) which can be inserted into the actuating receptacle (38) and is electrically isolated from the actuating element (40). [4] Safety door monitoring module according to claim 3, wherein the electrical component is an SMD resistor or a wire-wound resistor. [5] Safety door monitoring module according to one of claims 1 to 4, wherein the actuator (36) has at least one electrical contact (48, 50) via which the actuator (36) can be connected to a measuring circuit (62) in the base unit (34) when the actuator (36) is inserted into the actuator receptacle (38). [6] Safety door monitoring module according to claim 5, wherein the electrical contact (48, 50) is designed as a spring-loaded contact element (82) or as a pressure piece (88). [7] Safety door monitoring module according to one of claims 1 to 6, wherein the basic unit (34) is configured to detect the defined electrical resistance (42) by means of a voltage measurement and to recognize the presence of the actuator (36) in the actuator receptacle (38) by comparing a measured voltage value with an expected voltage value. [8] Safety door monitoring module according to claim 7, wherein the basic device (34) is configured to distinguish between a first state in which the actuator (36) is not inserted into the actuator receptacle (38), a second state in which the actuator (36) is inserted into the actuator receptacle (38), and a third state in which something is inserted into the actuator receptacle (38) that does not correspond to the actuator (36) by means of voltage measurement. [9] Safety door monitoring module according to one of claims 1 to 8, wherein the actuator (36) has at least one further defined electrical resistance (98) and the basic device (34) is configured to recognize a defined position of the actuator (36) in the actuator receptacle (38) on the basis of the defined electrical resistance (42) and the further defined electrical resistance (98) and to generate the safety door signal depending on the recognized position. [10] Safety door monitoring module according to any one of claims 1 to 9, wherein the actuator receptacle (38) has a mechanical form which interacts with a corresponding form of the actuator (36) to ensure accurate mechanical positioning and electrical contacting of the actuator (36).

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