GUARD SLIDE FOR A WORKING MACHINE

Description

[0001] The present invention relates to a protective slide for a working machine in the packaging industry according to claim 1 as well as to a working machine for processing packaging material in the packaging industry according to claim 7 and to a method for processing packaging material with a working machine in the packaging industry according to claim 10. State of the art

[0002] A wide variety of machines are known in the packaging industry. These include, for example, machines that can process packaging materials (such as plastic). For example, a thermoforming machine can create packaging cavities in the film from a film web or, more generally, a film body. A filling machine can place products (e.g., sausages or cheese) into the packaging cavities. A sealing station can then seal the filled packaging cavities with a top film.

[0003] Known packaging machines not only include transport devices for the packaging material to be processed, but also frequently include components (e.g., the upper and lower tools of a sealing station) that can be moved toward and away from each other to process the packaging material inserted between them. Such components and their relative movement pose a potential risk of injury to an operator if the operator can reach into the working area of ​​the machine where the packaging material is being processed.

[0004] Various possibilities are known from the state of the art to avoid or prevent the operator from interfering in the work area as far as possible.

[0005] For example, DE 10 2021 104083 A1 and DE 39 25 796 A1 disclose devices that can block a passage of the working machine through which packaging material can be fed into or removed from the work area, preventing operator intervention. These devices are designed as protective slides and are typically positioned in front of the passages of the working machine in such a way that an operator cannot intervene in the work area during a work operation. At the same time, it is known to use suitable sensors to determine whether the protective slide is in the desired position before the work operation is performed.

[0006] To meet safety requirements, it must be ensured that an operator does not inadvertently reach into the work area even when the protective slide is positioned in the protective position. This requires reliable detection of this protective position and even small deviations of the actual position of the protective slide from this protective position, which requires complex sensor units. This results in a large overall installation space for the protective slide, which can impact the installation space required for a packaging system. Work machines with protective elements and sensors for determining the positions of the protective elements are also known from DE 25 16 293 A1, US R E34 396 E, and EP 2 792 601 A1. Task

[0007] Based on the known state of the art, the technical problem to be solved is to specify a protective slide for a working machine in the packaging industry and a method for processing packaging material with a working machine in the packaging industry, which ensure reliable protection of an operator against accidental intervention in a working area of ​​a working machine and at the same time achieve a reduced size. Solution

[0008] This object is achieved according to the invention by the protective slide for a working machine in the packaging industry according to independent claim 1, the working machine in the packaging industry according to independent claim 7, and the method for processing packaging material with a working machine in the packaging industry according to independent claim 10. Advantageous developments of the invention are covered in the subclaims.

[0009] The protective slide according to the invention for a work machine for processing packaging material comprises a mounting element for connecting the protective slide to a work machine, a protective element arranged such that it can move relative to the mounting element, a first sensor element and a second sensor element arranged fixedly on the mounting element, wherein the protective element can be moved relative to the mounting element between a release position and a protective position and wherein the first sensor element and the second sensor element are designed to come into contact in the protective position of the protective element and to output a signal indicative of the contact, wherein the first sensor element is arranged such that it can be moved along with the protective element and a movement amplitude of the first sensor element is greater than a movement amplitude of the protective element.

[0010] The contact can be either a physical contact between the first sensor element and the second sensor element or a contact mediated by forces acting on it, such as electromagnetic forces. For example, if a threshold value of a magnetic force exerted on the second sensor element by the first sensor element is exceeded, the second sensor element can detect contact with the first sensor element and output a corresponding signal indicative of this contact.

[0011] The term "movement amplitude" refers to a distance traveled between a first point and a second point. The fact that the movement amplitude of the first sensor element is greater than the movement amplitude of the protective element is not limited here to the total distance traveled by the first sensor element when moving the protective element from the first position to the second position being greater than the distance traveled by the protective element between the first position and the second position. According to the invention, it is sufficient if the movement amplitude of the first sensor element, at least between a first point occupied by the protective element and a second point coinciding with the protective position, is greater than the distance traveled by the protective element between the first point and the second point.As a result, a comparatively small stroke or general distance traveled by the protective element is translated into a larger distance traveled by the first sensor element.

[0012] This means that even small changes in the position of the protective element, for example, compared to the protective position, have a comparatively large impact on the position of the first sensor element, so that the accuracy with which it is determined whether the protective element is in the protective position can be precisely determined by the effect of contact or its absence. This increases operator protection while simultaneously reducing the required installation space and the complexity of the sensors.

[0013] In one embodiment, the first sensor element and the second sensor element together form a magnetic circuit, wherein the second sensor element optionally comprises an actuatable magnetic switch and the first sensor element a magnet for actuating the magnetic switch. Thus, the first sensor element and the second sensor element together can implement the circuit, wherein one of the sensor elements comprises the actuatable magnetic switch and the other sensor element comprises the magnet. Magnetic circuits can be reliably actuated even over many operating cycles, thus ensuring operator protection even over a long operating period.

[0014] It can be provided that the movement amplitude of the first sensor element in a first movement section, which includes the release position, is less than or equal to the movement amplitude of the protective element in the first movement section, and that the movement amplitude of the first sensor element in a second movement section, which includes the protective position, is greater than the movement amplitude of the protective element in the second movement section. In the first movement section, the first sensor element can in particular be moved along with the protective element, so that the distance of any point on the first sensor element to any point on the protective element is constant during the movement. In the second movement section, the first sensor element is moved with a movement amplitude that is greater than the movement amplitude of the protective element, so that at least parts of the first sensor element experience a movement relative to the protective element.Since the increase in the movement amplitude of the first sensor element, which is advantageous for the protective effect, is only relevant in the area of ​​the protective position of the protective element in order to determine this correctly (by actuating the second sensor element), this embodiment realizes a structural simplification, in particular a reduced space requirement for the movement of the first sensor element.

[0015] In one embodiment, it is provided that the first sensor element is arranged on a lever that is rotatably mounted about an axis, wherein the axis divides the lever into a first lever arm and a second lever arm, wherein the second lever arm is shorter than the first lever arm and the first sensor element is arranged on the first lever arm, wherein the protective slide comprises a stop against which the second lever arm can strike when the protective element moves in the direction of the protective position, such that by rotating the lever about the axis, the first sensor element can be moved in the direction of the second sensor element. This mechanical design for realizing the different movement amplitudes of the first sensor element and the protective element is reliable and has low wear, so that reliable detection of the protective position of the protective element can be achieved even after long periods of operation.

[0016] It can be provided that the first lever arm has a greater mass than the second lever arm. This embodiment is particularly advantageous if the protective element occupies a lower height in the release position than in the protective position, but is not limited to this. Due to the different masses of the first lever arm and the second lever arm, the first sensor element can be reliably brought into a desired starting position due to the torque acting on the lever, so that contact with the second sensor element can preferably only be brought about by a movement of the protective element into the protective position, which increases the reliability of detecting when the protective element has assumed the protective position.

[0017] In one embodiment, the protective slide comprises a reset element arranged such that, upon movement of the protective element from the protective position to the release position, the reset element moves the first sensor element away from the second sensor element. This prevents the first sensor element from accidentally remaining close to the second sensor element or from coming into contact with the second sensor element.

[0018] In one embodiment, the protective element and the movement amplitude of the protective element define a region, and the mounting element, the first sensor element, and the second sensor element are arranged outside the region. The region is understood here as the space occupied entirely by the protective element during its movement amplitude and can, for example, be represented as the resulting space obtained when a surface completely surrounding the protective element moves along the movement amplitude. In this embodiment, the first sensor element and the second sensor element are therefore not arranged in a region traversed by the protective element, which allows a more compact design and, for example, enables the first sensor element and the second sensor element to be arranged below this region (for example, when the protective element is moved vertically).This reduces the space required for the protective slide.

[0019] The work machine according to the invention for processing packaging material comprises a feed opening for feeding packaging material, a work space for processing packaging material, a discharge opening for discharging processed packaging material from the work space, and a protective slide, for example according to one of the preceding embodiments, in the region of the feed opening and / or in the region of the discharge opening. The protective slide is arranged such that the protective element, in the protective position, blocks an operator from engaging the feed opening and / or the discharge opening. This work machine enables safe processing of packaging material.

[0020] It can be provided that the protective element, in the protective position, enables the transport of packaging material into the feed opening and / or the transport of processed packaging material out of the discharge opening. The packaging material can be, for example, a film web or film blanks, or connected or separate packaging trays. While the packaging material can be further conveyed even when the protective element is in the protective position, it still prevents an operator from interfering in the work area. The throughput of the working machine can thus be increased while maintaining operator safety.

[0021] The work machine can include a sealing station, a thermoforming machine, an inserting machine, an inspection device, and / or a disinfection device. For these machines, the use of the protective slider is advantageous, as it allows for a continuous supply of packaging material.

[0022] According to the invention, a method for processing packaging material with a working machine is provided, wherein the working machine comprises a feed opening for feeding packaging material, a working space, a discharge opening for discharging processed packaging material from the working space and a protective slide, wherein the protective slide is connected to the working machine via a mounting element of the protective slide and comprises a protective element arranged so as to be movable relative to the mounting element, a first sensor element and a second sensor element arranged fixedly on the mounting element, wherein the protective element can be moved relative to the mounting element between a release position and a protective position and wherein the first sensor element and the second sensor element come into contact in the protective position of the protective element and emit a signal indicative of the contact, wherein the first sensor element is arranged so thatthat it is moved along with the protective element and a movement amplitude of the first sensor element is greater than a movement amplitude of the protective element, wherein the method comprises enabling a work step of the work machine by a control unit of the work machine based on receiving the signal indicative of the contact. This method allows for safe processing of packaging material even in the presence of an operator.

[0023] It can be provided that the movement amplitude of the first sensor element in a first movement section, which includes the release position, is less than or equal to the movement amplitude of the protective element in the first movement section, and that the movement amplitude of the first sensor element in a second movement section, which includes the protective position, is greater than the movement amplitude of the protective element in the second movement section. This achieves a compact design of the work machine and, in particular, of the protective slide, which reduces the required space.

[0024] In one embodiment, the first sensor element is arranged on a lever mounted so as to be rotatable about an axis, the axis dividing the lever into a first lever arm and a second lever arm, the second lever arm being shorter than the first lever arm and the first sensor element being arranged on the first lever arm, the protective slide comprising a stop against which the second lever arm strikes when the protective element moves towards the protective position, and by rotating the lever about the axis, the first sensor element is moved towards the second sensor element. This mechanical design allows reliable detection of the position of the protective element in the protective position.

[0025] The first lever arm can be provided with a greater mass than the second lever arm. This ensures reliable resetting of the first sensor element, as the lever is forced into its initial position due to the applied torque.

[0026] In one embodiment, the protective slide comprises a reset element, and the first sensor element is moved away from the second sensor element by the reset element when the protective element moves from the protective position to the release position. This ensures reliable detection of a movement of the protective element out of the protective position.

[0027] The protective element and the movement amplitude of the protective element can define a region, and the mounting element, the first sensor element, and the second sensor element can be arranged outside the region. This embodiment enables a compact design.

[0028] It can be provided that the first sensor element and the second sensor element together form a magnetic circuit, wherein the second sensor element optionally comprises an actuatable magnetic switch and the first sensor element comprises a magnet for actuating the magnetic switch. This embodiment also enables long-term operation while maintaining consistent protection of the operator from injury.

[0029] Each of the preceding embodiments can be combined with each of the further described embodiments in the sense of the present disclosure. Short description of the characters

[0030] Fig. 1 shows a schematic view of a working machine with a protective slide according to an embodiment. Fig. 2 shows a feed opening with a protective slide according to an embodiment. Figs. 3 to 5 show a movement sequence of the protective element and the first sensor element according to an embodiment. Fig. 6 shows an embodiment of a return element. Detailed description

[0031] Fig. 1 shows a work machine 100 as part of a packaging machine 10. The work machine is intended to process packaging material 130, which can be in the form of one or more continuous film webs or contiguous or individual packaging trays (already filled or unfilled), for example. The invention is not limited in this regard or with regard to the design of the work machine. In the embodiment shown here, the work machine 100 is designed, for example, as a sealing station.

[0032] Sealing stations are generally known from the prior art and typically comprise an upper tool 101 and a lower tool 102, along with a working space 103 formed between them, in which the processing of packaging trays 130 containing product takes place. The upper tool 101 and the lower tool 102 can be moved toward each other according to the double arrow shown, so that the filled packaging trays and a sealing film applied to the packaging trays in the sealing station can be brought into contact with each other and bonded together by the application of heat to seal the packages.

[0033] For this purpose, the work machine 100 typically comprises a feed opening 144 and a discharge opening 143, which, as shown here, can be arranged on opposite sides of the work machine, wherein the feed opening 154 is arranged in front of the discharge opening 143 in the transport direction T of the packaging material 130, and the feed opening 144 and the discharge opening 143 can delimit the work space 103. The feed opening and the discharge opening 144 and 143 can be formed, for example, as openings in a protective wall or a casing of the work machine 100.

[0034] The work machine is shown here, by way of example, as being arranged between a transport device 141, which can feed packaging material 130 to the work machine 100, and a transport device 142, which can remove processed packaging material from the work machine 100. The design of the transport devices 141 and 142 is not limited. They can be, for example, conveyor belts and / or grippers, whereby the transport devices 141 and 142 can be designed according to suitability and, in particular, do not have to be identical.

[0035] While Fig. 1While FIG. 1 shows an example of a work machine 100 according to embodiments in the form of a sealing station, other embodiments of the work machine are also possible. In particular, the work machine can be designed as a sealing station, a thermoforming machine, an inserting machine, an inspection device, or a disinfection device. A packaging system comprising one or more of these work machines, for example, arranged one behind the other in the transport direction of the packaging material, is also conceivable.

[0036] The feed opening 144 and the discharge opening 143, as openings into the working space 103, generally pose a risk of injury, as an operator of the working machine could reach into the working space 103 while the working machine is in operation. At the same time, the feed opening and the discharge opening must be large enough to allow for any necessary repairs or the removal of packaging material in the event of a malfunction of the working machine.

[0037] In order to minimize the risk of injury to an operator during operation of the work machine 100, according to the invention, a protective slide 150, shown schematically here, is provided at least in front of the feed opening 144 and / or the discharge opening 143, which is arranged and designed to reduce or close the feed opening and / or the discharge opening to such an extent that an operator cannot intervene in the work space 103 during operation of the work machine 100. In the case of a cyclically operating machine, this can include the working step of the work machine (using the example of Fig. 1for example, the movement of the upper tool 101 and the lower tool 102 towards each other) can only be carried out if the protective slide or a protective element of the protective slide has been moved into a protective position which avoids, as far as possible, an intervention by an operator into the working space 103 by the remaining opening being so small that, for example, no finger or arm can be stretched through it into the working space 103.

[0038] The Fig. 2 shows a protective slide according to an embodiment in relation to the work machine 100. In the Fig. 2The work machine is again shown, by way of example, as a sealing station with an upper tool 101 and a lower tool 102, which are arranged to be movable relative to one another. In this embodiment, the protective slide 250 comprises a mounting element 260, which can be connected via one or more suitable connecting elements, for example screws 261, to the stationary lower tool 102 or another preferably stationary part (for example a casing in which the feed opening 144 or the discharge opening 143 is formed) of the work machine 100. In this sense, the mounting element 260 functions as a stationary frame, relative to which the protective slide 251 is arranged to be movable, in order to be moved in the direction of the double arrow shown and to close or open the feed opening 144 (or the discharge opening 143).If the following refers to the position of the protective slide 251 in the area of ​​the feed opening 144, it is understood that all embodiments of the protective slide and each of its parts as well as their function are also applicable to a positioning of the protective slide in front of the discharge opening 143 or for a protective slide in front of each of these openings.

[0039] If the protective slide 251 is moved upward in the embodiment shown here, the feed opening 144 decreases in size. If it is moved downward, the feed opening increases in size. Positioning the protective slide in front of the feed opening 144 in such a way that an operator can no longer reach into the work area is referred to as the protective position. Positioning the protective slide in front of the feed opening in such a way that an operator can no longer reach into the work area is referred to as the release position.

[0040] It may be provided that a supply of packaging material (in the Fig. 2not shown) into the working space 103 of the working machine is possible both in the release position of the protective slide 251, in which the working space 103 is accessible through the feed opening 144, and in the protective position, in which the working space 103 is not accessible to the operator through the feed opening 144. This is particularly advantageous with a continuous feed of packaging material. In alternative embodiments in which, for example, separate pieces of packaging material are fed into the working space 103 during cyclical operation of the working machine, it can be provided that no further packaging material is fed into the working space 103 through the feed opening during a work step. In this embodiment, it can be provided that the protective slide 251 completely closes the feed opening, so that no supply of packaging material (or analogously, no removal of packaging material from the discharge opening) is possible.

[0041] To move the protective element 251 relative to the mounting element 260 and relative to the feed opening 144, a drive element 270, for example in the form of a pneumatic cylinder, can be provided, which is operatively connected to the protective element 251 and can set it in motion. Instead of a pneumatic cylinder, a servo drive or an actuator can also be used here.

[0042] According to the invention, the protective slide further comprises a first sensor element 252, which is connected to the protective element 251 in such a way that it can be moved at least partially with the protective element 251. For this purpose, for example, a connecting element 254, for example in the form of a suspension for the first sensor element 252, can be provided, on which the first sensor element 252 is arranged and which is firmly connected to the protective element 251, so that the connecting element 254 follows the movement of the protective element 251.

[0043] Furthermore, the protective slide 250 comprises a second sensor element 253. The second sensor element 253 is arranged stationary relative to the mounting element 260 and can in particular be fastened to the mounting element 260.

[0044] According to the invention, the first sensor element and the second sensor element can interact in such a way that, upon contact (for example, touching or physical contact), they output a signal indicative of this contact. The arrangement of the first sensor element 252 relative to the protective element 251 around the arrangement of the second sensor element 253 is designed such that the first sensor element and the second sensor element are in touching contact with each other when the protective element 251 is arranged in the protective position, but in all other positions of the protective element, the first sensor element and the second sensor element have no (touching or physical) contact.

[0045] When the first sensor element and the second sensor element are in contact with each other, they can output a signal indicative of the contact, which can be transmitted to a control unit 280, shown schematically here. The control unit 280 can be, for example, a computer with a memory and processor unit, which has suitable programming to receive the signal indicative of the contact and, if necessary, process it.

[0046] Preferably, the control unit 280 can enable or disable the operation of the work machine and in particular the execution of a work step of the work machine (for example the sealing of packages or the moving of the upper tool 101 and the lower tool 102 towards each other) based on the received signal.

[0047] Preferably, the control unit only enables the work step when the signal indicative of contact is received, since then the protective element 251 is in the protective position, preventing the operator from interfering with the work area. If such a signal is not received, the control unit can block or disable the work step, thus minimizing the risk of operator injury.

[0048] Since the protective element 251 is typically moved back and forth between the protective position and the release position during continuous operation of the work machine, the first sensor element and / or the second sensor element can be configured to emit a signal at regular intervals (for example, every 2 ms to 50 ms, preferably every 2 ms to 5 ms) that indicates whether or not contact is made between the first sensor element and the second sensor element. After evaluating this signal, the control unit can then determine (almost) in real time and essentially continuously whether a work step can be released or remains blocked.Thus, it can be provided that when the control unit receives a signal indicative of no contact between the first sensor element and the second sensor element, the control unit blocks the work step and only releases it again when the control unit receives a signal indicative of contact between the first sensor element and the second sensor element.

[0049] In one embodiment, the first sensor element 252 and the second sensor element 253 together can form a magnetic circuit. One of the sensor elements comprises a magnet, and the other sensor element comprises a magnetic switch that can be actuated by the magnet, so that a signal can be generated that indicates the actuation of the magnetic switch by the magnet. The magnetic switch is preferably implemented as or as part of the second sensor element 253, and the magnet is or is part of the first sensor element 252. Since the magnetic switch must have a power supply and, if necessary, a physical data connection to the control unit 280, this embodiment has the advantage that the cable guide from and / or to the magnetic switch does not have to be moved during operation of the work machine, which reduces the susceptibility to errors.

[0050] According to the invention, it is provided that a movement amplitude of the first sensor element 252 is greater than the movement amplitude of the protective element 251. This is to be understood in such a way that when the protective element 251 moves from a first point to a second point, the protective element travels a distance of length L. The first sensor element 252, which essentially follows the movement of the protective element 251 via the connecting element 254, travels a greater distance in this case. This does not have to generally apply to the entire movement of the first sensor element 252 when following the movement of the protective element 251 from the release position to the protective position, but according to the invention, it is provided that this occurs at least for a partial range of the entire movement of the protective element from the release position to the protective position.

[0051] The movement of the protective element 251 from the release position to the protective position can be divided into a first movement section and a second movement section. The first movement section comprises the release position itself and a further point on the path of the protective element 251 from the release position to the protective position, wherein the further point does not correspond to the protective position of the protective element 251. In this movement section, the movement amplitude of the protective element 251 can be identical to the movement amplitude of the first sensor element 252, or the movement amplitude of the first sensor element 252 can be smaller than the movement amplitude of the protective element 251 in this first movement section.

[0052] The second movement section can extend from this point to the protective position. In this movement section, the total path traveled by the first sensor element 252 (i.e., its movement amplitude) is greater than the movement amplitude of the protective element. This results in a comparatively small change in the position of the protective element 251 around the protective position being translated into a large change in the position of the first sensor element 252, whereby the distance to the second sensor element 253 changes more significantly than the change in the position of the protective element 251. This increases the sensitivity of the sensor formed by the first sensor element and the second sensor element for the position of the protective element 251, since the contact is determined by the movement of the first sensor element relative to the second sensor element and thus the distance between them.

[0053] In one embodiment, this different movement amplitude of the first sensor element 252 and the protective element 251 is achieved in that the mounting element comprises a stop 255 against which the sensor element 252 or an element on which the first sensor element 252 is arranged can run and relative to which the first sensor element 252 can be set in rotation. As in the embodiments of the Fig. 3 and 5 As will be described later, a comparatively small change in the position of the protective element 251 can be converted into a comparatively large change in the position of the first sensor element 252 relative to the second sensor element 253.

[0054] To explain this, the Fig. 3 to 5 the movement sequence when moving the protective element from the release position ( Fig. 3 ) into the protective position ( Fig. 5 ).

[0055] In Fig. 3the protective element 251 is in the release position. A sensor is not absolutely necessary to determine the position of the protective element 251 in the release position, since the protection of the operator from injury essentially depends on the reliable detection of the protective element 251 in the protective position. However, it can be provided that a contact sensor 395 is arranged, for example, on the mounting element 260, which comes into contact with the protective element 251 when the protective element is positioned in the release position. This sensor can send a signal to the control unit 280 (see Fig. 2 ), which thus also receives the information that the protective element is in the release position. This can be used, for example, to signal to the operator that they can intervene in the working area of ​​the machine. However, this is only optional.

[0056] In the embodiment shown here, the first sensor element 252 is located at a distance h from the stop 255. In the embodiment shown, the first sensor element 252 is arranged on a lever which is rotatably mounted about a rotation axis R. In the enlarged schematic view in the Fig. 3It can be seen that the lever 390 is arranged on the rotation axis R in such a way that the rotation axis R divides the lever into a first lever arm 391 and a second lever arm 392. The first sensor element is arranged on the first lever arm 391 and the length L1 of the first lever arm 391 is greater than the length L2 of the second lever arm. Preferably, it can also be provided that the mass of the first lever arm 391 is greater than the mass of the second lever arm 392. Without further physical contact, for example with the stop 255, the torque on the lever caused by the different masses of the lever arms causes the lever to be arranged in the starting position shown here without contact with the stop 255. The movement of the first lever arm 391 with the first sensor element in a direction of rotation away from the protective element 251, that is, in the illustration of the Figure 3The downward movement can also be limited by a stop (not shown here). Without such a stop, the lever will follow the torque so that the first lever arm 391 points vertically downward, as this represents the energetic minimum.

[0057] In Fig. 4 a situation is shown in which the protective element 251 (not shown here) is raised by the height h1, which corresponds to the distance h from the Fig. 3is identical, has been moved from the release position towards the protective position. During this movement, the first sensor element 252 follows the position of the protective element from the position 491 shown here in dashed lines, and the shorter lever arm 392 comes into contact with the stop 255 at the end of the movement from the original position 491. This movement section is selected such that the lever 490, on which the first sensor element 252 is arranged, has not yet undergone any rotation about the rotation axis R. Accordingly, the movement amplitude of the first sensor element 252 during this movement section is identical to the movement amplitude of the protective element 251 (both travel the distance h).

[0058] In the situation shown here, the protective element has not yet been moved into the protective position, but still needs to be moved further toward the protective position. For example, the length h1 can correspond to 90% of the total distance traveled by the protective element from the release position to the protective position.

[0059] When the protective element continues to move, the lever arm 392 no longer moves beyond the stop 255 due to the fixed position of the stop 255. Instead, the lever is rotated about the rotation axis R, as shown in Fig. 5 is shown.

[0060] The protective element 251 is now moved a distance Δ toward the protective position, reaching the protective position after traveling a distance of length Δ. The protective element has therefore traveled a total distance of h + Δ.

[0061] As in the Fig. 5As can be seen, during this movement of the protective element by the distance Δ, the lever 590 is now rotated from the position shown in Fig. 5 from the dashed position 589 by the angle α. This is linked to a movement of the first sensor element 552 by the distance h2. If the angle α is expressed in parts of 2π, the movement amplitude of the first sensor element 252 corresponds to α 2 π L 1 , where L1 is the distance of the first sensor element 552 from the rotation axis R along the lever 590, which for the purpose of explanation is compared with the length of the first lever arm (see Figure 2 ). The distance travelled by the shorter lever arm corresponds to the distance Δ travelled by the first protective element and can be calculated as a first approximation as α 2 π L 2 (with L2 as the length of the lever arm measured from the rotation axis R).

[0062] Thus, the ratio of the movement amplitude of the first sensor element to the movement amplitude Δ of the protective element 251 is approximately L1 / L2 and thus greater than 1, so that the first sensor element 552 experiences a larger movement amplitude compared to the movement amplitude Δ.

[0063] As in Fig. 5 As shown, the first sensor element is in contact with the second sensor element at the end of this movement, so that a signal indicative of this contact can be output.

[0064] The sensor formed by the first sensor element 552 and the second sensor element 553 can have a tolerance that results in the output of a corresponding signal indicative of contact even if this contact has not yet been established. However, due to the ratio of the movement amplitude of the protective element and the movement amplitude of the first sensor element, this corresponds to an even smaller movement of the protective element out of the protective position. This improves the accuracy with which the positioning of the protective element in the protective position can be determined.

[0065] Furthermore, a position of the protective element slightly outside the protective position results in a comparatively large distance between the first sensor element and the second sensor element, so that even if the position of the protective element deviates slightly from the protective position, no contact is made between the first sensor element and the second sensor element, so that the control unit can reliably block the work step of the working machine.

[0066] The accuracy or sensitivity can be increased by increasing the ratio of L1 and L2. Thus, the length L1 of the first lever arm, on which the first sensor element 552 is arranged, can be at least three times as long, preferably five times as long, particularly preferably seven times as long as the length L2 of the shorter lever arm. Using the latter example, a deviation of the position of the protective element from the protective position of 1 mm can be translated into an approximate distance of 7 mm between the first sensor element and the second sensor element. This makes it possible to detect deviations in the position of the protective element 251 from the protective position with high accuracy, thus ensuring safe operation of the work machine.

[0067] Figure 6shows a further embodiment in which the protective slide further comprises a return element 695. The return element is arranged fixedly relative to the mounting element 260 in this embodiment, and can in particular be firmly connected thereto (for example via screw connections). The return element 695 is preferably arranged such that the lever arm 392, upon movement of the protective element in the direction of the protective position (see Figures 3 to 5 ) can be guided past the return element at a distance D in the direction of the stop 255. As with reference to the Figures 3 to 5 As described, when the stop 255 is reached, the lever arm 392 of the lever 490 is rotated about the rotation axis R and the lever arm 391 is rotated in the direction of the second sensor element 253 so that the first sensor element 252 and the second sensor element 253 can come into contact when the protective element reaches the protective position.

[0068] In this position, the second lever arm 392 extends a distance P in one direction over the return element 695, as shown here.

[0069] If the protective slide is moved from the protective position back towards the release position, this movement causes the second lever arm 392 to rotate about the rotation axis R, which is effected by the fixed return element 695, since the second lever arm 392 extends at least partially over the return element 695 in the protective position of the protective element. The return element 695 thus causes the first sensor element 252 to be moved away from the second sensor element 253 when the protective element moves from the protective position to the release position. This embodiment ensures that the lever arm 392 and thus also the first lever arm 391 and the first sensor element 252 are reliably moved away from the second sensor element 253 when the protective element is moved from the protective position to the release position.

[0070] It can be provided that the return element comprises a support surface 698 pointing in the direction of the stop 255 and / or an at least partially curved side surface 697 sloping downwards from the stop 255. The second lever arm 392 can rest on the support surface when the protective element is in the protective position. As a result, the second lever arm 392 can be positioned between the stop 255, which extends above the second lever arm 392, and the support surface 698, which can prevent the second lever arm 392 from being accidentally moved out, so that contact between the first sensor element 252 and the second sensor element 253 is maintained as long as the protective element is in the protective position.

[0071] The curved side surface can advantageously ensure that the second lever arm 392 can be moved out of the position that the second lever arm 392 assumes when the protective element is in the protective position without jamming with the return element 695 when the protective element is moved from the protective position to the release position.

[0072] For this purpose, the second lever arm 392 can preferably comprise a receiving area 696 which is delimited by material of the second lever arm in the direction of the stop 255 and into which the return element 695 can engage upon rotation of the second lever arm 392.

[0073] In addition to enabling and disabling a work step of the work machine based on the position of the protective slide, the work machine can further comprise a film detection mechanism, which is arranged, for example, in the work space and / or in the feed opening and / or the discharge opening and is designed to detect the presence and / or absence of packaging material at least in the work space. Regardless of the position of the protective slide, it can be provided that the work step or a function of the work machine is also disabled if the film detection mechanism determines that no packaging material is present in the work area.

Claims

1. Protective slide (150) for a work machine (100) for processing packaging material (130), said protective slide (150) comprising an assembly element (260) for connecting said protective slide (150) to a work machine (100), a protective element (251) arranged to be movable relative to said assembly element (260), a first sensor element (252) and a second sensor element (253) fixedly arranged at said assembly element (260), wherein said protective element (251) can be moved relative to said assembly element (260) between a release position and a protection position and wherein said first sensor element (252) and the second sensor element (253) are configured to come into contact in the protection position of said protective element (251) and to output a signal that is indicative of the contact, characterized in that said first sensor element (252) is arranged such that it can be moved along with said protective element (251) and an amplitude of motion of said first sensor element (252) is greater than an amplitude of motion of said protective element (251).

2. Protective slide (150) according to claim 1, wherein said first sensor element (252) and said second sensor element (253) together form a magnetic circuit, wherein said second sensor element (253) optionally comprises an actuatable magnetic switch and said first sensor element (252) comprises a magnet for actuating said magnetic switch.

3. Protective slide (150) according to claim 1 or 2, wherein the amplitude of motion of said first sensor element (252) in a first motion section that comprises the release position is smaller than or equal to the amplitude of motion of said protective element (150) in the first motion section and wherein the amplitude of motion of said first sensor element (252) in a second motion section that comprises the protection position is greater than the amplitude of motion of said protective element (150) in the second motion section.

4. Protective slide (150) according to one of the claims 1 to 3, wherein said first sensor element (252) is arranged at a lever (390) which is mounted to be rotatable about an axis (R), wherein said axis divides said lever (390) into a first lever arm (391) and a second lever arm (392), wherein said second lever arm (392) is shorter than said first lever arm (391) and said first sensor element (252) is arranged at said first lever arm, wherein said protective slide (150) comprises a stop (255) against which said second lever arm (392) can abut when said protective element (251) moves in the direction of the protection position so that, with a rotation of said lever (390) about said axis (R), said first sensor element (252) can be moved in the direction of said second sensor element (253), wherein said first lever arm (391) optionally has a greater mass than said second lever arm (392).

5. Protective slide (150) according to one of the claims 1 to 4, wherein said protective slide comprises a return element (695) which is arranged such that said return element (695) moves said first sensor element (252) away from said second sensor element (253) when said protective element (251) moves from the protection position to the release position.

6. Protective slide (150) according to one of the claims 1 to 5, wherein said protective element (251) and the amplitude of motion of said protective element define a region, and said assembly element (260), said first sensor element (252), and said second sensor element (253) are arranged outside said region.

7. Work machine (100) for processing packaging material (130), said work machine comprising a feed opening (144) for feeding packaging material, a work space (103) for processing packaging material, a discharge opening (143) for discharging processed packaging material from said work space (103), and a protective slide (150) according to one of the claims 1 to 6 in the region of said feed opening (144) and / or in the region of said discharge opening (143), wherein said protective slide (150) is arranged such that said protective element (251) in the protection position blocks an operator from reaching into said feed opening (144) and / or said discharge opening (143).

8. Work machine (100) according to claim 7, wherein said protective element (251) in the protection position enables packaging material to be transported into said feed opening (144) and / or processed packaging material to be transported out of said discharge opening (143).

9. Work machine (100) according to claim 7 or 8, wherein said work machine (100) comprises a sealing station, a deep-drawing machine, a loading machine, an inspection device, and / or a disinfection device.

10. Method for processing packaging material (130) with a work machine (100), wherein said work machine comprises a feed opening (144) for feeding packaging material, a work space (103), a discharge opening (143) for discharging processed packaging material from said work space (103), and a protective slide (150), wherein said protective slide (150) is connected to said work machine (100) by way of an assembly element (260) of said protective slide (150) and comprises a protective element (251) arranged to be movable relative to said assembly element (260), a first sensor element (252) and a second sensor element (253) fixedly arranged at said assembly element, wherein said protective element (251) can be moved relative to said assembly element (260) between a release position and a protection position and wherein said first sensor element (252) and said second sensor element (253) come into contact in the protection position of said protective element (251) and output a signal that is indicative of the contact, characterized in that said first sensor element (252) is arranged such that it is moved along with said protective element (251) and an amplitude of motion of said first sensor element (252) is greater than an amplitude of motion of said protective element (251), wherein the method comprises releasing a work step of said work machine (100) by a control unit (280) of said work machine (100) based on receiving said signal that is indicative of the contact.

11. Method according to claim 10, wherein the amplitude of motion of said first sensor element (252) in a first motion section that comprises the release position is smaller than or equal to the amplitude of motion of said protective element (251) in the first motion section and wherein the amplitude of motion of said first sensor element (252) in a second motion section that comprises the protection position is greater than the amplitude of motion of said protective element (251) in the second motion section.

12. Method according to claim 10 or 11, wherein said first sensor element (252) is arranged at a lever (390) which is mounted to be rotatable about an axis (R), wherein said axis divides said lever into a first lever arm (391) and a second lever arm (392), wherein said second lever arm (392) is shorter than said first lever arm (391) and said first sensor element (252) is arranged at said first lever arm, wherein said protective slide (150) comprises a stop (255) against which said second lever arm (392) can abut when said protective element (251) moves in the direction of the protection position so that, with a rotation of said lever (390) about said axis, said first sensor element (252) is moved in the direction of said second sensor element (253), wherein said first lever arm (391) optionally has a greater mass than said second lever arm (392).

13. Method according to one of the claims 10 to 12, wherein said protective slide comprises a return element (695) and wherein said first sensor element is moved away from said second sensor element (253) by said return element (695) when said protective element (251) moves from the protection position to the release position.

14. Method according to one of the claims 10 to 13, wherein said protective element (251) and the amplitude of motion of said protective element define a region, and said assembly element (260), said first sensor element (252), and said second sensor element (253) are arranged outside said region.

15. Method according to one of the claims 10 to 14, wherein said first sensor element (251) and said second sensor element (253) together form a magnetic circuit, wherein said second sensor element (253) optionally comprises an actuatable magnetic switch and said first sensor element (252) comprises a magnet for actuating said magnetic switch.