Suction cup device with wear monitoring device

Description

[0001] The invention relates to a suction gripper device with a suction body and with a wear monitoring device for monitoring a wear condition of the suction body.

[0002] Suction gripper devices are used to grip objects using negative pressure and are used, for example, as end effectors in vacuum handling systems. They typically comprise at least one suction body that defines a suction chamber and has a contact section or sealing lip for contact with the object to be gripped. To grip an object, the suction body is placed with the contact section against the object to be gripped, and then the suction chamber of the suction body is subjected to negative pressure. To deposit the object, the suction chamber is then ventilated again.

[0003] Suction grippers with differently designed suction bodies are known. For example, elastomer suction grippers are known in which the suction body consists of an elastomer material that forms a seal against the outer surface of the object to be gripped when suctioned on. Suction grippers are also known in which the suction body consists of a porous foam material through which the object to be gripped can be suctioned.

[0004] When such a suction body is used as intended, especially when repeatedly picking up and placing an object, wear and tear usually occurs, particularly due to mechanical abrasion in the contact area. Such wear and tear can, for example, impair the sealing effect of the suction body, thus making it impossible to grip an object with the desired reliability. Therefore, it is important to be able to monitor the wear and tear of the suction body.

[0005] For this purpose, it is known, for example, from EP 1 816 094 B1 to equip the absorbent body, at least in sections, with an element whose color changes over time and thus represents a state of wear of the absorbent body.

[0006] EP 1 826 160 B1 also discloses acoustically monitoring the wear condition of a suction body. Specifically, it is proposed to provide a light barrier in the suction body, which is exposed by wear of an element located in the area of ​​the sealing lip and then triggers an alarm via a loudspeaker.

[0007] From EP 4 0 49 812 A1 it is also known to monitor a wear condition of an absorbent body with a proximity sensor, wherein the proximity sensor comprises several sensor units which monitor the presence of absorbent body material.

[0008] Another suction gripper is known from WO 2012 / 034716 A1, in which the degree of wear is monitored by means of electrical measurements.

[0009] The invention is based on the object of being able to reliably determine the wear condition of the suction body of a suction gripper device using simple means.

[0010] This object is achieved by a suction gripper device having the features of claim 1.

[0011] The suction gripper device comprises at least one suction body for suctioning up an object. In particular, the suction body can be an elastomer suction body or a porous foam material. The suction body can in particular be part of a higher-level suction gripper, for example a surface suction gripper. During its intended use, i.e. in particular during repeated suctioning up and depositing of an object, the suction body is subject to wear and tear, at least in sections. In particular, the suction body is subject to mechanical abrasion. Wear and tear occurs in particular in a contact section or sealing lip of the suction body, by means of which the suction body is applied to an object to be suctioned up.

[0012] The suction gripper device also comprises a wear monitoring device for monitoring the state of wear, in particular the degree of wear, of the suction body. In particular, the wear monitoring device can be designed to detect that a predetermined degree of wear, in particular a predetermined level of material abrasion, of the suction gripper has been reached.

[0013] The wear monitoring device comprises a translucent test structure having a light entry region, in particular a light entry surface, and a light exit region, in particular a light exit surface. The test structure is particularly designed such that light penetrating the test structure through the light entry region is guided to the light exit region.

[0014] The test structure can be provided on the absorbent body in such a way that, upon reaching a predetermined degree of wear, in particular upon exceeding a predetermined amount of abrasion, a light conduction property and / or a light reflection property of the test structure is changed, in particular such that a light intensity and / or a propagation direction of light emerging from the light exit area is changed. Advantageously, the test structure can be designed in such a way that a light conduction property and / or a light reflection property continuously changes as the absorbent body progressively wears, which enables close, in particular continuous, monitoring of a wear state.

[0015] Alternatively or additionally, the test structure can also be provided on the suction body in such a way that the light exit area or the light entry area is only exposed at least in sections when a predetermined degree of wear of the suction body is reached, in particular when a predetermined amount of abrasion is exceeded, so that light can only escape from the light exit area to the environment of the suction body or light can only penetrate into the test structure through the light entry area. In particular, the light exit area can be covered or closed when the suction gripper device is in a new state, for example by a cover layer or by suction body material, so that light radiated into the test structure through the light entry area cannot escape from the light exit area. It is also conceivable that the light entry area is covered or closed when the suction gripper device is in a new state.is closed so that light cannot penetrate into the test structure through the light entry area. The light entry area or the light exit area can therefore have an opaque state (when the suction gripper device is new), which is converted into a translucent state when a predetermined degree of wear of the suction body is reached. It is also conceivable for the test structure to be designed in such a way that the light exit area or the light entry area is initially exposed when the predetermined degree of wear of the suction body is reached, and then, as the wear of the suction body progresses, the size or geometry of the light exit area or the light entry area is changed or is no longer changed.

[0016] Such a suction gripper device enables the wear condition of the suction body to be reliably and automatically monitored using simple means. Wear detection is based on the fundamental principle that, as a result of wear caused by use, particularly when a predetermined degree of wear is reached, the intensity and / or propagation direction of light emerging from the test structure changes. This can be done either by changing a light conduction property of the test structure as a result of the wear or by exposing the light exit area of ​​the test structure in the first place, thus allowing light to exit the light exit area in the first place. Such a local change in light intensity in the light exit area of ​​the test structure can then be detected, and the suction body can be monitored for its wear condition.The test structure is particularly designed such that the reaching of a predetermined degree of wear of the suction body can be detected as a change in the intensity or propagation direction of light emerging from the light exit area of ​​the test structure. The predetermined degree of wear can, in particular, be a limiting degree of wear of the suction body, upon reaching which the suction body must be replaced immediately or at least in the near future (e.g., after at most another 100 gripping cycles).

[0017] According to the invention, the wear monitoring device comprises an optical detection device configured to detect light emerging from the light exit region of the test structure. In particular, the optical detection device can be designed to detect a local change in light intensity at the light exit region of the test structure (e.g., as a result of a change in a light-conducting property of the test structure or the at least partial exposure of the light entry region or the light exit region). The optical detection device can, for example, comprise a light intensity sensor and / or a camera. The optical detection device is preferably arranged such that it can detect the test structure, in particular the light exit region of the test structure.

[0018] The test structure is integrated into the suction body. The suction body comprises a suction body wall that defines an interior suction chamber. The test structure is formed in the suction body wall.

[0019] The test structure can be integrated into the suction body or embedded in the suction body material in such a way that the light exit area or the light entry area of ​​the test structure is covered by the suction body material in a (unworn) new state of the suction body and is only exposed when a predetermined degree of wear of the suction body is reached, in particular when a predetermined amount of abrasion is exceeded. In this respect, the test structure can be integrated into the suction body in such a way that the light exit area or the light entry area is arranged at a distance from a contact surface or sealing lip of the suction body for contact with an object to be gripped in a new state of the suction body. Such a design enables particularly direct and thus precise monitoring of the wear condition of the suction gripper.

[0020] It is also conceivable for the test structure to be designed and arranged such that the light exit area or the light entry area, when the suction gripper device is new, is covered by a wear layer that wears away as the suction body itself wears away due to use. Advantageously, the wear layer can be made of the same material as the suction body. The suction body and the wear layer then have, in particular, the same abrasion resistance. The wear layer can be opaque. The thickness of the wear layer is preferably such that the wear layer is only worn away when the suction body has reached the specified degree of wear.

[0021] According to the invention, the test structure is formed by a translucent channel. The translucent channel can, in particular, have a first channel end, which provides the light entry area, and a second channel end, which provides the light exit area. In this respect, it is conceivable that the first or the second channel end is initially closed when the suction gripper device is in its new state and is only opened when a predetermined degree of wear of the suction body is reached, in particular when a predetermined amount of abrasion is exceeded. It is also conceivable that both channel ends are already open when the suction gripper device is in its new state, but a geometry of the first or second channel end or of a channel section between the first and second channel end changes as a result of wear.

[0022] According to the invention, the translucent channel is formed by a local recess in an absorbent body wall of the absorbent body. Such a design is particularly simple and cost-effective to produce since the number of individual components is reduced. Furthermore, such a design is particularly robust in use. It is conceivable for the local recess to be provided during the original shaping of the absorbent body. It is also conceivable for the local recess to be added subsequently, e.g. by drilling or punching. The local recess can be formed in the absorbent body in such a way that the translucent channel thus provided is closed off by absorbent body material at one end of the channel when the absorbent body is new, and in particular this channel end is only opened when a predetermined degree of wear of the absorbent body is reached, in particular when a predetermined amount of abrasion is exceeded.

[0023] Within the scope of a further embodiment, the local recess can be arranged such that upon reaching a predetermined degree of wear, in particular upon exceeding a predetermined amount of abrasion, of the absorbent body, a further (secondary) light exit region is exposed along an optical path from the light entry region to the (primary) light exit region. In such a configuration, exposing the further (secondary) light exit region changes, in particular, a light conduction property and / or a light reflection property of the test structure, so that the intensity of the light arriving at and exiting from the (primary) light exit region is changed.In particular, it is conceivable that, as a result of the exposure of the further (secondary) light exit area, light which is radiated into the test structure through the light entry area exits partially or completely through the further (secondary) light exit area, so that the intensity of the light exiting at the (primary) light exit area decreases. Such a change in light intensity can then be detected by the detection device, and the reaching of a predetermined degree of wear can be monitored. With such a configuration, the light entry area and the (primary) light exit area can already be open when the absorbent body is in its new state, so that light which penetrates the test structure through the light entry area is already guided to the (primary) light exit area in its new state and exits from there. The local recess can then, for example,be designed in the suction body in such a way that both channel ends are open, and when a predetermined degree of wear of the suction body is reached, in particular when a predetermined amount of abrasion is exceeded, a further channel opening is opened along the optical path between the first channel end and the second channel end.

[0024] Within the scope of an advantageous development, the light entry area, for example, a first channel end of the test structure designed as a translucent channel, and the light exit area, for example, a second channel end of the test structure designed as a translucent channel, can open on the same side of the absorbent body. For example, it is conceivable for the test structure or the translucent channel to be U-shaped. The test structure is then preferably provided by a light-guiding element.

[0025] Advantageously, the suction body can have a suction side for sucking in the object and a connection side, particularly one opposite the suction side, for connection to a vacuum supply. It can then be advantageous if the test structure is designed such that the light entry area and the light exit area (or a first and a second channel end of the translucent channel) open into the connection side of the suction body. This makes it easy to monitor the wear status of the suction body during operation of the suction gripper device, particularly when the object is gripped.

[0026] According to the invention, the wear monitoring device comprises a light source for emitting a test light beam. The light source is arranged such that the test light beam can enter the test structure through the light entry area. A design with a light source enables particularly reliable monitoring of the wear condition, independent of environmental influences. In particular, the detection device can be matched to the light source, e.g., a wavelength of the test light beam. The light source can be, for example, a lamp, an LED, or a laser light source.

[0027] Within the scope of a particularly compact design, the detection device and / or the light source can be attached to the suction body. In the above-described design, in which the light entry area and the light exit area open into a connection side of the suction body, the light source and the detection device can preferably both be provided on the connection side of the suction body, so that the contact side is free for contact with an object.

[0028] The suction gripper device can also comprise a control device for controlling the light source and / or the detection device.

[0029] Regardless of the design of the test structure or the detection device, the wear monitoring device can also comprise an evaluation device that interacts with the detection device. The evaluation device can be part of the control device. In particular, the evaluation device can comprise a data processing system. The evaluation device can in particular be configured to generate a wear signal, which represents the wear state of the suction body, as a function of an optical signal detected by the detection device. This makes it possible to determine the wear state of the suction body in a simple and automated manner. The evaluation device can be provided separately from the suction gripper. For example, it is conceivable that the evaluation device is part of a cloud computer system. The detection device can then be connected to the suction gripper via a communication interface, e.g.a WLAN or LAN interface, via which measurement signals can be transmitted to the evaluation device. However, it is also possible for the evaluation device to be located on the suction gripper itself. The evaluation device can, for example, include a display device that visualizes the wear status of the suction body.

[0030] Advantageously, the evaluation device can be configured to generate the wear signal by comparing a measurement signal received by the detection device with a reference measurement signal stored in a memory device of the evaluation device. In particular, the wear signal can represent a wear state of the suction body suitable for operation if the measurement signal exceeds a predetermined threshold value, which is stored or can be stored in the memory device of the evaluation device. The wear signal can represent a wear state of the suction gripper that is unsuitable for operation if the measurement signal falls below the threshold value.

[0031] During the intended use of the suction gripper device, it may happen that the suction body is subject to particularly severe wear at a certain point, for example, if the suction body always engages an object with the same edge. In order to be able to detect local differences in wear, it can therefore be advantageous in a general aspect if several test structures are provided. The test structures can then be distributed evenly over the circumference of the suction body, for example. It is conceivable that only one detection device is provided, which monitors all test structures. It is also conceivable that a separate detection device is provided for each of the plurality of test structures.

[0032] The invention is explained in more detail below with reference to the figures. They show: Figure 1 schematic representation of a design of a suction gripper device in a new state in a partial sectional view; Figure 2 schematic representation of the suction gripper device according to Fig. 1 with already partially worn suction body; Figure 3 schematic representation of a further embodiment of a suction gripper device in a new condition in a partial sectional view; Figure 4 schematic representation of a further embodiment of a suction gripper device in a new condition in a partial sectional view; Figure 5 schematic representation of a further embodiment of a suction gripper device in a new condition in a partial sectional view; and Figure 6 schematic representation of the suction gripper device according to Fig. 5 with the suction body already partially worn out.

[0033] In the following description and in the figures, the same reference symbols are used for identical or corresponding features.

[0034] The Figure 1 shows a first embodiment of a suction gripper device, designated overall by reference numeral 10. The suction gripper device 10 comprises a suction body 12, which in the illustrated example is designed as an elastomer suction cup. In embodiments not shown, the suction body 12 can also be a porous foam material, for example.

[0035] The suction body 12 serves to suck in and thus grip an object (not shown). When used as intended, the suction body 12 is placed with a contact section 14 or sealing lip 14 against an outer surface of the object to be gripped, and the object is then sucked in using negative pressure. For this purpose, the suction body 12 comprises a plurality of negative pressure channels 16, which can be supplied with negative pressure via a negative pressure connection 18. For example, the negative pressure connection 18 can be connected to a negative pressure generating device (not shown). To deposit a sucked-in object, the negative pressure channels 16 can then be vented again, for example via the connection 18.

[0036] In the course of this intended use, i.e. with repeated suction and depositing of an object, the suction body 12 is subject to wear and tear at least in sections, particularly in the area of ​​the contact section 14. This is stated in the Figures 1 and 2 schematically illustrates the suction gripper device 10 in a new condition (cf. Fig. 1 ) and a used condition of the suction body 12 (cf. Fig. 2 ). A main wear direction is indicated in the figures by the arrow designated by reference numeral 20. This wear is, in particular, mechanical abrasion of the suction body material, for example, due to friction between the suction body 12 and the suctioned object.

[0037] In order to be able to monitor a wear condition of the suction body 12, the suction gripper device 10 comprises a wear monitoring device 22. The wear monitoring device 22 comprises a translucent test structure 24, which in the example shown is integrated into an absorbent body material 26 of the absorbent body 12.

[0038] The test structure 24 has a light entry area 28 and a light exit area 30. In the example, the test structure is designed as a light-permeable channel 32, with a first channel end 34 providing the light entry area 28 and a second channel end 36 providing the light exit area 30.

[0039] In the example shown, the test structure 24 or the light-permeable channel 32 is formed by a local recess 38 in the absorbent body material 26.

[0040] As from Figure 1As can be seen, the test structure 24 or the light-permeable channel 32 is designed such that the light entry area 28 (first channel end 34) is open to the surroundings of the absorbent body 12. The light exit area 30 (second channel end 36), however, is in the Figure 1 In the new state of the suction gripper device 10 shown, it is covered by the suction body material 26. The light exit area 30 and the second channel end 36 are thus arranged at a distance from a contact surface 40 of the contact section 14 in the new state. This has the consequence that light 42, which is radiated into the test structure 24 through the light entry area 28, cannot leave the light exit area 30 in the new state of the suction body 12 (cf. Fig. 1 ).

[0041] When a predetermined degree of wear of the absorbent body 12 is reached, i.e., when a certain amount of material of the absorbent body 12 has already been worn away, the second channel end 36 is opened at least partially, thus exposing the light exit area 30 at least partially. As a result, light 42 entering the test structure 24 through the light entry area 28 can exit the light exit area 30, which can then be detected as a local change in light intensity.

[0042] For this purpose, the suction gripper device 10 comprises a detection device 44, which is designed to detect light emerging from the light exit area 30, in particular its intensity, and thus to monitor the wear condition of the suction body 12. The detection device 44 can, for example, comprise a light intensity sensor or a camera.

[0043] In the illustrated example, the wear monitoring device 22 comprises a light source 46, which is configured to introduce a test light beam 48 through the light entry area 28 into the test structure 24. For example, the light source 46 can be an LED or a laser source.

[0044] In the Figures 1 and 2 In the example shown, the test structure 24 is arranged such that the light entry area 28 opens out at a connection side 50 of the suction body 12 opposite the contact section 14 or a suction side 49. In this respect, it is advantageous if the light source 46 is also arranged on the connection side 50.

[0045] As in the Figures 1 and 2 As shown by way of example, the light source 46 can be attached to the suction body 12. However, it is also possible for the light source 46 to be arranged at a distance from the suction body 12 (cf. Figure 3). In this case, it is conceivable that the light source 46 is optically connected to the light entry area 28 via a light-guiding device (not shown), e.g. an optical fiber.

[0046] The Figure 4 shows a further embodiment of a suction gripper device 10, in which, in comparison to the embodiment according to Fig. 1 the light source 46 and detection device 44 are swapped in their positions. In this case, the second channel end 36 of the translucent channel 32 (test structure 24) forms a light entry area 28 and the first channel end 34 forms the light exit area 30. In this embodiment, the light entry area 28 is then covered by the absorbent material 26 when the absorbent body 12 is new. The light exit area 30, however, is open to the surroundings of the absorbent body 12 or to the detection device 44. Otherwise, the embodiment according to Figure 4 the design according to the Figures 1 and 2 , so that in order to avoid repetition, reference is made to the above statements.

[0047] The Figure 5 shows a further embodiment of a suction gripper device 10, in which the light entry area 28 and the (primary) light exit area 30 of the test structure 24 open into the same side, in the example in the direction of the connection side 50. Light radiated through the light entry area 28 is thus guided to the light exit area 30 when the suction body 12 is new. The test structure 24 is arranged such that upon reaching a predetermined degree of wear, a further (secondary) light exit area 52 is exposed, so that light radiated through the light entry area 28 exits to a certain extent or exclusively through the further (secondary) light exit area 52 (cf. Fig. 6). As a result, the intensity of the light emerging from the (primary) light exit region 30 decreases, which can then be detected by the detection device 44.

[0048] In the example shown according to Fig. 5 The test structure 24 is U-shaped, with the middle leg running parallel to the contact surface 40. In embodiments not shown, however, it is also conceivable that the test structure 24 has a different geometry.

[0049] Regardless of the design of the test structure 24 and the detection device 44, the suction gripper device 10 may also comprise a control device 54 (exemplary and schematically only for the design according to Fig. 3indicated), which is designed to control the light source 46 and / or the detection device 44. The control device 54 can in particular comprise an evaluation device 56. As mentioned above, the evaluation device 56 can be configured to generate a wear signal, which represents the wear state of the absorbent body 12, as a function of an optical signal detected by the detection device 44.

Claims

1. Suction gripper device (10), comprising - a suction body (12) which, when used as intended, is subjected to use-related wear, at least in portions; - a wear monitoring device (22) for monitoring a wear state of the suction body (12), characterized in that the wear monitoring device (22) comprises a translucent test structure (24) having a light entry region (28) and a light exit region (30), the test structure (24) being provided on the suction body (12) in such a way that when a predetermined degree of wear of the suction body (12) is reached, in particular when a predetermined amount of abrasion is exceeded, a light conduction property of the test structure (24) is changed or the light exit region (30) or the light entry region (28) is only then exposed, at least in portions, in that the wear monitoring device (22) also has a light source (46) for emitting a test light beam (48) through the light entry region (28) of the test structure (24), in that the wear monitoring device (22) also comprises an optical detection device (44) which is designed to detect light emerging from the light exit region (30) of the test structure (24), characterized in that the test structure (24) is a translucent channel (32) which is formed by a local recess (38) in a suction body wall of the suction body (12).

2. Suction gripper device (10) according to claim 1, wherein the test structure (24) is designed and arranged such that the light exit region (30) or the light entry region (28) in a new state of the suction body (12) is covered by suction body material (26) or by a wear layer which wears out in the course of use-related wear of the suction body (12).

3. Suction gripper device (10) according to one of claims 1 or 2, wherein the test structure (24) is arranged such that when a predetermined degree of wear of the suction body (12) is reached, in particular when a predetermined amount of abrasion is exceeded, a further light exit region (52) is exposed along an optical path from the light entry region (28) to the light exit region (30).

4. Suction gripper device (10) according to any of the preceding claims, wherein the light entry region (28) and the light exit region (30) open out on the same side of the suction body (12).

5. Suction gripper device (10) according to one of claims 3 or 4, wherein the suction body (12) has a suction side (49) for sucking in the object and a connection side (50) in particular opposite thereto for connection to a vacuum supply, wherein the light entry region (28) and the light exit region (30) of the test structure (24) open into the connection side (50).

6. Suction gripper device (10) according to any of the preceding claims, wherein the detection device (44) and / or the light source (46) are attached to the suction body (12).

7. Suction gripper device (10) according to any of the preceding claims, wherein the wear monitoring device (22) also comprises an evaluation device (56) interacting with the detection device (44), which evaluation device is designed to generate a wear signal, which represents the wear state of the suction body (12), depending on an optical signal detected by the detection device (44).