Gripping device with gripping arms that can be moved towards each other and an actuating device for moving the gripping arms

Abstract

The invention relates to a gripping device (1) with at least two gripping arms (2) which can be moved towards one another from an open position into a closed position, and with at least one actuating device (3) for moving the gripping arms (2), wherein each gripping arm (2) has two bending elements (4, 5) which are arranged in a wedge shape relative to one another and extend in a main direction, and at least one spacer element (6) arranged therebetween and oriented transversely to the gripping arm (2), wherein the bending elements (4, 5) are connected to one another in a force-transmitting manner at their distal ends with respect to the main direction and are spaced apart from one another at their proximal ends with respect to the main direction, wherein at least one of the bending elements (4, 5) is displaceable by means of the actuating device (3) with respect to the main direction relative to the other bending element (4, 5) in order to bring about a curvature of the gripping arm (2) in the closed position.In order to create a gripping device (1) whose gripping process can be carried out particularly quickly, it is proposed that the actuating device (3) has a restoring element (7) which can be prestressed to a restoring force for applying force to the displaceable bending element (4, 5) in the direction of the closed position of the associated gripping arm (2), a motor (8) which prestresses the restoring element (7) to the restoring force, and a coupling device (9) for coupling the restoring element (7) to the motor (8) for the open position of the gripping arm (2) and for decoupling the restoring element (7) from the motor (8) for the closed position of the gripping arm (2).

Description

[0001] The invention relates to a gripping device with at least two gripping arms movable towards one another from an open position to a closed position, and with at least one actuating device for moving the gripping arms. Each gripping arm has two bending elements arranged in a wedge shape relative to one another and extending in a main direction, and at least one spacer element arranged between the bending elements and oriented transversely to the gripping arm. The bending elements are connected to one another in a force-transmitting manner at their distal ends with respect to the main direction and are spaced from one another at their proximal ends with respect to the main direction. At least one of the bending elements is displaceable relative to the other bending element with respect to the main direction by means of the actuating device in order to cause a curvature of the gripping arm in the closed position.

[0002] Gripping devices of this type can be designed as a pair of gripping arms that can be moved relative to one another, or as a basket-like gripping device with a plurality of gripping arms arranged circumferentially relative to a gripping volume. To grip an object, at least one of the gripping arms is movable relative to the other gripping arms, so that the gripping arms can be moved toward one another to reach the closed position. Preferably, however, several gripping arms or all gripping arms are designed to be movable.

[0003] Gripping devices are useful in many areas of technology, for example for holding objects in a defined position, but also for grasping, in particular catching, an object to be removed from a part of the environment.

[0004] Specifically, the invention relates to an aircraft, in particular an unmanned aircraft, such as a drone, comprising a fuselage and a propulsion device arranged on the fuselage for propelling the aircraft through an environment. The aircraft is equipped with a gripping device for gripping, in particular catching, an object.

[0005] In the context under consideration here, objects that can be captured by the aircraft's gripping device are, in particular, unmanned aerial vehicles such as drones. Through carelessness or malicious intent, such objects can enter restricted areas such as airports, major events, or military sites. Therefore, there is a need to prevent unauthorized entry into such no-fly zones through drone defense measures or to prevent unauthorized objects from leaving the zone.

[0006] Furthermore, aircraft or gripping devices of the aforementioned type can be used to grasp high-voltage lines, hazardous / explosive materials, or similar items. Gripping devices can also be used on unmanned underwater vehicles. In principle, the gripping devices described can be used not only for vehicles such as aircraft, ground vehicles, or watercraft, but also as stationary gripping devices.

[0007] The gripping devices considered in the invention make use of the so-called fin ray effect, which is known from the technical field of bionics. This fin ray effect is modeled on the behavior of fish fins. When a lateral force is applied, the fish fin does not bend in the direction of the force, as expected, but rather against the direction of the force. This effect is based on the structure of the individual fin rays. These each consist of two flexible, elastic bending elements that converge at the tip and together form an acute-angled triangle. Between the two bending elements are transverse elements that keep the bending elements at a distance and enable elastic movements.

[0008] EP 2 241 403 B1 discloses a holding and / or spreading tool for craft or medical purposes, which utilizes the fish fin effect. The tool has holding and / or spreading jaws that are movable relative to one another. The movement is caused by a first cheek of a jaw being displaced relative to a second cheek of the jaw by actuating a tension / compression means connected thereto, thus triggering the fish fin effect. Two jaws of the tool, which are opposite one another with respect to a gap, each have two opposing cheeks that are flexible in a manipulation plane of the tool and extend from a proximal end to a distal end of the jaw. The cheeks are connected at the distal end so as to transmit tensile force and are held spaced apart from one another at the proximal end.Between the proximal and distal ends, the jaws are pivotally connected to each other by at least one hinge element. One of the jaws can be displaced longitudinally relative to the other. This triggers a gripping or spreading movement of the jaw.

[0009] Other devices that utilize the fish fin effect are also known. WO 2008 / 128 780 A1, for example, discloses a drive device, in particular for a flexible flapping wing of a watercraft, with a bending element configured essentially in the shape of a wedge, which has at least two bending sections extending away from a drive, the distance between which decreases in the direction away from the drive, and which are coupled at the ends in a force-transmitting manner. The bending sections are held movable relative to one another on the drive side essentially along the longitudinal axis of the wedge. By a motor-driven change in the relative position of the bending sections to one another, the bending element can be curved.

[0010] CN 1 11 645 081 A discloses an unmanned aerial vehicle with a gripping device attached to the aircraft via a movable arm. The gripping device has a plurality of clamping jaws. The clamping jaws are manufactured by 3D printing as a hollow structure with intermediate struts made of an elastic plastic and can be moved synchronously towards each other by an electrically driven push rod. The clamping jaws can adapt to the shape of an object using the fish fin effect, but only when one of the clamping jaws comes into contact with the object and is thereby subjected to a lateral force. The original shape of the clamping jaws is regained once the object is released and the applied force is thus removed.

[0011] In the field of unmanned aerial vehicles, gripping devices are also known that perform a gripping function exclusively through gripping arms moved toward each other by means of a linear drive or screw drive. The fish-fin effect is not utilized in this case. CN 106239541 A, for example, discloses a gripping device with an annular support structure on which several gripping arms are mounted for pivoting and sliding movement. The gripping arms can be moved apart and together by means of a screw drive.

[0012] KR 10 2021 0 009 660 A discloses a gripping device for a drone. The gripping device comprises several parallel pairs of gripping arms that can pivot toward each other and are pivotably mounted on a support. The pivoting movements of the gripping arms are mechanically coupled to one another, with one pivoting movement being initiated by an electrically operated linear drive.

[0013] DE 10 2023 002 971 A1 discloses a gripping device with at least one multi-element gripping jaw movably coupled to a support device, and a drive device for moving the gripping jaw relative to the support device. The gripping jaw has a movable gripping structure with an outer structure for absorbing compressive forces and an inner structure adjacent to a gripping space for absorbing tensile forces. When a compressive force is applied to the outer structure by means of the drive device, the inner structure bulges and the gripping space is narrowed. For a return movement, the gripping jaw is pivoted back into its starting position by means of a return device after a locking mechanism securing the gripping position has been released.

[0014] DE 10 2020 207 036 A1 discloses a gripper with a gripper base body, a drive motor arranged on the gripper base body and at least one pair of gripper fingers which are mounted on the gripper base body, wherein at least one of the gripper fingers is adjustably mounted on the gripper base body driven by the drive motor such that the gripper can be opened and closed by a movement of the at least one gripper finger driven by the drive motor.

[0015] DE 10 2020 126 448 B4 discloses a device for loading a container, comprising a guide device on which at least one displaceable hand element is provided. The hand element comprises a plurality of finger elements, each of which has at least two flexible flank elements extending jointly from one end of the finger element to the opposite end of the finger element, which are flexibly connected to one another via a plurality of webs, so that the finger elements can be adjusted from a curved position to an extended position and back. A drive unit is provided for displacing the flank elements from the curved position to an extended position and vice versa.

[0016] DE 10 2007 017 416 B3 discloses a sorting device comprising a sorting gate pivotable about a suspension area, which defines a sorting channel for the passage of objects to be sorted. The side surfaces of the sorting channel are arranged on two spring-elastic side walls that approach one another in a funnel-like manner and are combined to form a gate structure by transversely extending, rigid coupling struts hinged to them. An actuator device engages this gate structure in such a way that the two side walls arch in the same direction, thus causing the pivoting movement of the sorting gate. Fluid-operated drives with tension actuators or pressure actuators are proposed as the actuator device.

[0017] EP 2 502 714 B1 discloses a holding device for holding objects, comprising at least one holding unit comprising a base and a holding structure with flexible side walls and coupling struts. The holding unit is provided with detection means for detecting deformation of the side walls and a lever mechanism.

[0018] The disadvantage of all the gripping devices mentioned above is that the gripping arms move relatively slowly from the open to the closed position.

[0019] The invention is based on the object of creating a gripping device whose gripping process can be carried out particularly quickly.

[0020] The object of the invention is achieved according to the invention with the features of the independent patent claims. Further preferred embodiments can be found in the dependent patent claims.

[0021] The invention relates to a gripping device with at least two gripping arms movable towards one another from an open position to a closed position, and with at least one actuating device for moving the gripping arms. Each of the gripping arms has two bending elements arranged in a wedge shape relative to one another and extending in a main direction, and at least one spacer element arranged therebetween and oriented transversely to the gripping arm. The bending elements are connected to one another in a force-transmitting manner at their distal ends with respect to the main direction and are spaced from one another at their proximal ends with respect to the main direction. At least one of the bending elements is displaceable relative to the other bending element with respect to the main direction by means of the actuating device in order to cause a curvature of the gripping arm in the closed position.According to the invention, the actuating device comprises a return element, a motor, and a coupling device arranged in operative connection between the return element and the motor. The return element can be preloaded by the motor to a return force acting in the direction of the closed position. The return force is designed to displace the displaceable bending element of the associated gripper arm toward the closed position. The coupling device coupling the return element to the motor is designed and configured to decouple the return element from the motor to bring about the closed position of the gripper arm and to connect the return element to the motor to bring about the open position of the gripper arm.

[0022] In the form of the return element that can be preloaded to the restoring force, the actuating device has a particularly fast-reacting element that is suitable for suddenly applying the restoring force to the movable bending element of the gripper arm, thereby bringing the gripper arm into the closed position. In contrast to the prior art, there is no need to wait for the time period that a servomotor would need to move the movable bending element relative to the stationary bending element of the gripper arm. The preloading of the return element occurs before and independently of the subsequent release of the return element, during which the restoring force is suddenly released. This means that the time-consuming subtask of preloading the return element is independent of the application of the released restoring force to the gripper arm.The release of the restoring force, for example after releasing a locking mechanism of the pre-tensioned restoring element, occurs with the assistance of the coupling device, which decouples the restoring element from the motor. This allows the gripper arm to be explosively moved from the open position to the closed position, following the restoring force of the restoring element. The restoring element changes from the tensioned position to the relaxed position. Once the restoring element has relaxed and the closed position of the gripper arm has been reached, the restoring element can be coupled to the motor again via the coupling device in order to be pre-tensioned for another release process. The restoring element acts either directly or indirectly on the movable flexure element and can thus cause a relative displacement of the two flexure elements of the gripper arm.The application of force to the gripper arm triggers the fish fin effect, which causes the gripper arm to deform toward the closed position.

[0023] In the closed position, the gripper arm is moved towards one or more opposing gripper arms.

[0024] In the open position of the gripper arm, the two flexural elements of the gripper arm are preferably extended. The return element is preloaded to the return force. The coupling device couples the return element to the motor. The return mechanism is preferably locked, in particular by the motor, to fix the open position of the gripper arm until the motor is decoupled from the return element for the closed position of the gripper arm.

[0025] The term "flexural elements extending in a main direction" does not mean that the flexural element must be straight, i.e., may only extend in one plane. Rather, flexural elements extending in a main direction also include curved ones. Thus, according to one possible embodiment, the flexural elements can be curved both in the preloaded state and in the relaxed state of the return element. What is important is that the two flexural elements of the same gripper arm are pointedly connected to one another via their distal ends, while they are displaceable relative to one another at the opposite, distal ends, namely in a longitudinal direction of the gripper arm. For this purpose, one of the flexural elements is preferably stationary, while the other flexural element is displaced.

[0026] Due to the previously described design of the gripping arms as a fish fin structure, the respective gripping arm can additionally deform passively in the closing direction upon contact with an object, in particular an object held between the gripping arms of the gripping device, in particular in addition to the curvature of the gripping arm actively caused by the displacement of the displaceable bending element.

[0027] The return element can be a spring element. A constant-force spring is particularly recommended for applying force evenly across the length of the return element. Such a constant-force spring is particularly preferably a coil spring.

[0028] Several spring elements assigned to different gripper arms can be preloaded jointly by one and the same motor and / or reset simultaneously by a common release mechanism. In this respect, the same motor can be used for preloading the respective spring elements for several or even all gripper arms of the gripping device, as well as the same coupling device for coupling and uncoupling the reset elements.

[0029] The coupling device of the gripping device can, in particular, comprise a coupling body rotatable about a rotational axis with radially displaceably mounted coupling elements. The coupling elements are configured to establish a mechanical operative connection to the motor. For this purpose, the coupling elements can be displaced relative to the coupling body by means of an actuator. The coupling body can, for example, be designed as a cylindrical body that rotates about its longitudinal axis. The coupling elements can be radially retracted into the coupling body or extended out of the coupling body. In the retracted position of the coupling elements, the coupling body—and thus the return element coupled to the coupling body—is decoupled from the motor.In the extended position of the coupling elements, however, they engage with corresponding elements of the motor, establishing a mechanical operative connection between the return element and the motor. The return element can then be preloaded to the return force by the motor. The return element or an associated active element can be permanently or detachably connected to the coupling body, i.e., be operatively connected.

[0030] Particularly preferably, the clutch device can be designed as a so-called "dog box." Such clutch devices are known, for example, from motorsports, for initiating a shifting operation in a flash. Shifting between two different clutch states is possible without transmission synchronization. The advantage is the high shifting speed achieved.

[0031] The actuator, which serves to radially displace the clutch elements relative to the clutch body, can preferably be an electric motor. The actuator can, for example, be operatively connected to the clutch elements via a corresponding toothing. According to one embodiment, sliding cranks (Scotch-yoke gears) are operatively connected between the actuator and the clutch elements, which convert a rotational movement into a linear movement. For example, the actuator can drive a gear mounted on the clutch body, which, via the sliding cranks, causes the clutch elements to radially retract or extend from the clutch body. A particularly central drive of the clutch elements via a common actuator preferably includes synchronous operation of all sliding cranks, with each sliding crank interacting with a clutch element.

[0032] The coupling device, in particular the coupling body rotatable about the rotation axis, can have a tensioning device for pretensioning the return element and / or for pretensioning a tensioning means connected to the return element. The tensioning device can in particular be a winding device. The tensioning device can, for example, be designed such that it allows a partial region of the return element or of a tensioning means operatively connected to the return element to be wound onto the circumferential surface of the coupling body. Upon rotation of the coupling body, at least a length section of the return element or a length section of the tensioning means connected thereto is wound onto the coupling body, whereby the return element is subjected to a restoring force required to bring about a closed position of the gripper arm.The tensioning device connected to the return element is preferably a rope, wire, or thread that can be easily rolled in and out. This facilitates the winding process around the coupling body. The coupling body can have guide elements and / or receiving elements for the tensioning device on its circumferential surface to prevent it from sinking downward due to gravity.

[0033] Furthermore, it is proposed that a push and / or pull element engages the movable bending element of the gripper arm, which is in mechanically operative connection with the return element of the actuating device. For example, a plate element can be provided as the push element, which is dimensionally stable and is connected to the movable bending element or merges into it as a single piece. A pull element within the meaning of the invention can be, for example, a wire, rope, or thread, which is suitable for exerting a force on the movable bending element. In particular, the pull element can be designed identically to the tensioning means of the tensioning device.

[0034] According to one embodiment, the return element has an interface, for example a fastening element, at its end pointing in the direction of action towards the bending element of the gripper arm or the coupling device, on which interface both the tension element connected to the bending element and the tensioning means connected to the coupling device engage. Tensioning the return element by means of the tensioning means of the coupling device thus simultaneously relieves the load on the displaceable bending element and thus returns the gripper arm to the open position. Releasing the tensioning element, for example by unwinding the tensioning means from a winding device, leads to a relaxation of the return element and a drawing in of the bending element of the gripper arm connected to the tension element, thereby bringing about the closed position of the gripper arm.

[0035] The bending elements and / or the spacer element of the gripper arm can be made at least partially of an elastic plastic. In particular, they can comprise a carbon fiber reinforced plastic (CFRP). Other materials can also be suitable for forming the bending elements or the at least one spacer element. It is essential that the material has elastic properties so that a lateral force applied to the gripper arm leads to a deformation of the gripper arm structure according to the fish fin effect.

[0036] In addition to the gripping device described above, the invention proposes an aircraft, in particular an unmanned aircraft. The aircraft has a fuselage and a drive device arranged on the fuselage for moving the aircraft through an environment. The aircraft has a gripping device of the type described above, with an actuating device for moving the gripping arms, which has a restoring element that can be preloaded to a restoring force for applying force to a displaceable bending element of the gripping arm in the direction of the closed position of the associated gripping arm, a motor that preloads the restoring element to the restoring force, and a coupling device for coupling the restoring element to the motor for the open position of the gripping arm and for decoupling the restoring element from the motor for the closed position of the gripping arm.

[0037] With regard to the features of the gripping device, reference is made to the preceding explanations to avoid repetition. The proposed features and embodiments are accordingly relevant for an aircraft according to the invention with a gripping device.

[0038] According to one embodiment, the aircraft can be a drone, for example a multicopter, which monitors a no-fly zone assigned to an airport, a military site, an event venue, or something else. The term "drone" here refers, among other things, to devices referred to in the literature as, for example, Unmanned Aerial System (UAS), Unmanned Aircraft (UA), Remotely Piloted Aircraft System (RPAS), multicopter, fixed-wing aircraft, or unmanned aerial vehicle. Such aircraft or other unmanned aerial vehicles can also be purchased and operated by hobby pilots. The aircraft preferably has a sensor device configured to detect an object that has entered the no-fly zone without authorization. The sensor device can, in particular, have optical sensors, for example one or more cameras and / or one or more light barriers.Acoustic sensors, temperature sensors, radar sensors or other sensors can also be used.

[0039] Preferably, the gripping device of the proposed aircraft is configured and designed to pick up at least partial areas of such an object between its gripping arms. The focus here is on removing the object completely or largely from the exclusion zone. Alternatively, the gripping device can perform handling tasks when working on high-voltage lines, handling hazardous and / or explosive materials, and similar tasks.

[0040] When the aircraft is in the usual orientation during movement, the gripping device of the aircraft is preferably arranged on the fuselage in such a way that the gripping device can be opened upwards. The gripping device is thus arranged above the fuselage of the aircraft, namely where an object to be gripped, for example an intruder drone, is usually located. This allows the gripping device to be used as a type of upwardly open catching basket that can be closed by the gripping arms and thus securely holds a captured object. If the captured object no longer has an active propulsion, the force of gravity acting on the object advantageously ensures that the object is pushed further into the volume enclosed by the gripping arms of the gripping device. This ensures particularly safe transport of the object using the gripping device.Alternatively, according to a further embodiment, the gripping device can be arranged below the fuselage of the aircraft.

[0041] It is proposed that the gripping device be arranged on the fuselage such that the proximal ends of the gripping arms are at a distance of less than 100 mm from the fuselage. In particular, the distance between a proximal end region of a gripping arm and the fuselage is less than 50 mm, particularly preferably even less than 25 mm. Due to the particularly small distance at which the gripping arms are arranged on the fuselage, the gripping device is not attached to the fuselage of the aircraft via a long connecting arm or similar spacer elements, for example, but rather is arranged either directly or almost directly. As a result, no moments resulting from a movement of a connecting arm are introduced into the aircraft.The overall system of aircraft and gripping device thus remains sufficiently stable and rigid to not impair the vehicle's movement, while also enabling precise gripping tasks. This stability and rigidity are particularly advantageous for intercept maneuvers with high acceleration and deceleration loads. Furthermore, the short distance between the aircraft's fuselage and gripping device results in aerodynamic advantages, both when the gripping device is loaded and unloaded.

[0042] As previously mentioned, the gripping device of the aircraft is preferably assigned a sensor device for detecting an object to be gripped. The aircraft also advantageously has a control device for operating the actuating device in response to a detection signal from the sensor device. As soon as the sensor device detects an object to be gripped in a monitored sub-area of ​​the environment, the control device controls the actuating device of the gripping device such that the restoring element, preloaded to the restoring force, is suddenly released. For this purpose, the restoring element is preferably decoupled from the motor of the actuating device by the coupling device, which is arranged in operative connection between the motor and the restoring element, breaking the connection to the motor.The restoring element can then, following the restoring force, apply the restoring force to the movable bending element and displace it relative to the stationary bending element, which then ultimately causes the curvature of the gripping arm and the closed position of the gripping device is reached.

[0043] Advantageous further developments of the invention emerge from the patent claims, the description and the drawings.

[0044] The advantages of features and combinations of several features mentioned in the description are merely exemplary and can be effective alternatively or cumulatively, without the advantages necessarily having to be achieved by embodiments according to the invention.

[0045] With regard to the disclosure content – ​​not the scope of protection – of the original application documents and the patent, the following applies: Further features can be found in the drawings – in particular the illustrated geometries and the relative dimensions of several components to one another, as well as their relative arrangement and operative connection. The combination of features of different embodiments of the invention or features of different patent claims is also possible, deviating from the chosen references of the patent claims, and is hereby encouraged. This also applies to features that are illustrated in separate drawings or mentioned in their description. These features can be combined with features of different patent claims.Likewise, features listed in the patent claims may be omitted for further embodiments of the invention, but this does not apply to the independent patent claims of the granted patent.

[0046] The number of features mentioned in the patent claims and the description is to be understood as meaning that exactly this number or a greater number than the stated number is present, without the need for the explicit use of the adverb "at least." For example, if reference is made to one gripper arm, this is to be understood as meaning that exactly one gripper arm, two gripper arms, or more gripper arms are present. The features mentioned in the patent claims may be supplemented by further features or may be the only features present in the subject matter of the respective patent claim.

[0047] In the following, the invention is further explained and described with reference to preferred embodiments shown in the figures. Fig. 1 shows an aircraft according to the invention with a gripping device in a side view. Fig. 2 shows a perspective view of a gripping arm of the gripping device according to Fig. 1. Fig. 3 shows a side view of the gripper arm according to the Fig. 1 and Fig. 2. Fig. 4a shows a schematic diagram of a gripper arm according to a possible embodiment. Fig. 4b shows a side view of an opening position of the gripper arm. Fig. 4c shows a side view of a closed position of the gripper arm. Fig. 5a shows a schematic diagram of a gripper arm according to another embodiment. Fig. 5b shows a side view of the gripper arm according to Fig. 5a in an open position. Fig. 5c shows a side view of the gripper arm in a closed position. Fig. 6 shows a perspective view of the gripping device from above. Fig. 7 shows an actuating device of the gripping device during a closed position of the gripping arm. Fig. 8 shows the actuating device of the gripping device according to Fig. 7 during an opening position of the gripper arm. Fig. 9 shows a perspective view of a coupling device of the actuating device according to the Fig. 7 and Fig. 8.

[0048] Fig. Figure 1 shows a possible embodiment of an aircraft 18 with a gripping device 1 for catching, in particular, flying objects 23. The aircraft 18 having the gripping device 1 is embodied here as an unmanned aircraft 18, namely a flying drone. The object 23 to be caught is also a flying drone.

[0049] The aircraft 18 has a fuselage 19, which is connected in the usual way to a drive device 20 in order to propel the aircraft 18 through the environment. The drive device 20 here includes several propellers. A control device 24 is arranged in the fuselage 19. The control device 24 is designed, on the one hand, to control the drive device 20 of the aircraft 18 and, on the other hand, to control other functions. The aircraft 18 also has a sensor device 22, which can have one or more sensors. Here, the sensor device 22 has optical sensors, in particular cameras, which can detect an object 23 to be captured in the environment. The control device 24 evaluates the detection signals of the sensor device 22 and controls the gripping device 1 such that the object 23 can be captured by the gripping device 1.

[0050] The gripping device 1 has a plurality of gripping arms 2, which are attached in a ring shape to an upper side of the fuselage 19 of the aircraft 18. Each gripping arm 2 has a longitudinal extension that essentially points away from the fuselage 19 of the aircraft 18. The gripping arms 2 can be moved towards one another to carry out a gripping process and can be moved away from one another again accordingly to open a gripping volume enclosed by the gripping arms 2. The gripping device 1 is connected to the upper side of the fuselage 19 in such a way that a proximal end of each gripping arm 2 is only a small distance 21 from the upper side of the fuselage 19. This distance 21 is less than 25 mm here, so that the gripping arms 2 are attached essentially directly to the fuselage 19 of the aircraft 18.

[0051] As particularly in the Fig. 2 and Fig. 3, the gripping arms 2 of the gripping device 1 each have two bending elements 4, 5 which are connected to one another at a distal end and are arranged essentially in a wedge shape relative to one another. Here, the bending elements 4, 5 are each designed as flat plate elements. Alternatively, however, the invention functions just as well if the bending elements are curved (also) in the open position of the gripping arm 2. It is essential that the opposing bending elements 4, 5 are connected to one another in a force-transmitting manner at their distal end relative to the fuselage 19 of the aircraft 18. Extending between the bending elements 4, 5 here are a plurality of spacer elements 6 which are oriented transversely to the longitudinal extent of the gripping arm 2 and which are mounted via joints on the one hand on the first bending element 4 and on the other hand on the second bending element 5.The spacer elements 6 keep the two bending elements 4, 5 at a distance from each other and influence the shape of the gripper arm 2 in its open position and closed position.

[0052] Each bending element 4, 5 extends in at least one main direction, which differs from a main direction of the other bending element 4, 5. At their proximal ends, the two bending elements 4, 5 are inserted into a guide device 25, which is designed like a housing here. The guide device 25 serves to guide the movement of at least one of the bending elements 4, 5. This will be explained later. The guide device 25 does not have to be designed like a housing, as shown here. Rather, it can alternatively be an open guide slot.

[0053] One of the bending elements 4, 5, here the bending element 4, is displaceable relative to the other bending element 5 in its main direction. The displacement movement of the bending element 4 is predetermined by the guide device 25. The other bending element 5 is arranged stationary relative to the guide device 25. An actuating device 3 is used to displace the displaceable bending element 4, which will be described later with reference in particular to the Fig. 7 to 9 will be explained further.

[0054] The Fig. 4a to c and Fig. Figures 5a to c first illustrate the so-called fish fin effect used for the invention. The prerequisite for applying the fish fin effect is the design of the gripper arms 2 with the previously described wedge-shaped bending elements 4, 5 and at least one spacer element 6 oriented transversely to them and connecting the bending elements 4, 5. The fish fin effect redirects a force acting transversely to the bending elements 4, 5 on the gripper arm 2 in such a way that the gripper arm 2 does not bend away from the applied force, but instead toward it. This effect was copied from fish fins in the field of bionics, which behave in this way.

[0055] Due to the movable design of at least one of the bending elements 4, 5, the fish fin effect is actively induced, not just passively, when the gripper arm 2 comes into contact with an object 23. By moving the movable bending element 4, 5, a lateral thrust or tensile force is actively exerted on the gripper arm 2 as needed, causing the gripper arm 2 to bend.

[0056] The functionality is Fig. 4a to c and Fig. 5a to c. Fig. Figure 4 shows a design in which a movable bending element 4 is displaced relative to the opposite bending element 5 by applying a shear force to the movable bending element 4. The movable bending element 4 is designed here as a push rod. As a result of the application of the shear force to the movable bending element 4, the opposite bending element 5 is compressed, so that it bends towards the applied force, as shown in Fig. 5c. The spacer elements 6 permanently keep the two bending elements 4, 5 at a distance and influence the resulting curved shape of the gripper arm 2.

[0057] In the Fig. 5a to c illustrate an alternative embodiment in which a tensile force acts on the movable bending element 4. According to this embodiment, the movable bending element 4 can be displaced by a non-rigid element, for example, by means of a traction cable acting on the bending element. In this embodiment, too, the bending element 4 bends in the direction of the resulting force, namely such that the gripping arm 2 is moved toward one or more opposing gripping arms 2. As shown in Fig. As shown in Figure 5c, the movable bending element 4 bends with a smaller radius of curvature than the opposite, stationary bending element 5.

[0058] In addition to the triggering of the fish fin effect through the active, particularly mechanical, application of a pushing or pulling force to the movable flexural element 4, a passive fish fin effect remains. This means that when the gripper arms 2 come into contact with the object 23 to be captured, the contact resistance also causes a deformation of the respective gripper arm 2 or its flexural elements 4, 5. The gripper arms 2 can thus additionally adapt to the shape of the gripped object 23.

[0059] The actuating device 3 for moving the gripping arms 2 is described below using the Fig. 6 to 9 explained in detail

[0060] Fig. Figure 6 initially shows a perspective view of the gripping device 1 from above. In the illustration, the gripping arms 2 are each in their open position, in which the bending elements 4, 5 are maximally stretched. The actuating device 3 is located centrally between the gripping arms 2, namely here such that the actuating device 3 is arranged coaxially to a circumferential line of the successive gripping arms 2. Each gripping arm 2 is assigned its own return element 7, which here is designed as a constant force spring, namely in particular as a spiral spring. The return elements 7 of all gripping arms 2 are centrally pre-tensioned by a motor 8 of the actuating device 3. In order to move the gripping arms 2 from the pre-tensioned open position ( Fig. 8) into the relaxed closed position ( Fig. 7), the return element 7 is separated from the motor 8 by means of an intermediate coupling device 9.

[0061] Fig. 7 shows the gripper arm 2 in the curved, closed position. To achieve this closed position, the return element 7, which is preloaded by the motor 8, is suddenly decoupled from the motor 8 by the coupling device 9. The return element 7 relaxes and pulls the movable bending element 4 of the gripper arm 2 toward itself, namely via a push and / or pull element 17 arranged between the bending element 4 and the return element 7. The push and / or pull element 17 here is a pull element 17, namely a cable that engages the proximal end of the movable bending element 4. The displacement of the bending element 4 relative to the opposite, stationary bending element 5 is guided by the guide device 25.

[0062] In the Fig. In the tensioned state shown in Figure 8, the return element 7 is connected to the coupling device 9 via a tensioning means 16. Via the coupling device 9, there is an operative connection to the motor 8, which locks the position of the tensioned return element 7. For this purpose, the coupling device 9 has coupling elements 12 that lock the open position of the gripping arms 2 by engaging the coupling elements 12 in corresponding elements of a gear 13 arranged upstream of the motor 8.

[0063] The coupling device 9 has a coupling body 11 rotatable about a rotational axis 10, on which the coupling elements 12 are displaceably mounted. The coupling elements 12 are radially displaceable relative to the coupling body 11 or the rotational axis 10 and can be moved into and out of the coupling body 11. The movement of the coupling elements 12 is caused by an actuator 14 designed as an electric motor, which is connected to the actuator 14 via a gear element 26, namely a gearwheel rotatable about the rotational axis 10.

[0064] The gear element 26 displaces the coupling elements 12 in a Fig. 9, the so-called Scotch-Yoke arrangement (crank slider) is shown in more detail. The rotational movement of the gear element 26 is transformed into a linear movement of the clutch elements 12.

[0065] To bring the gripper arm 2 into the closed position according to Fig. 7, the coupling elements 12 are displaced radially inward into the coupling body 11. This abruptly decouples them from the gear 13 and the motor 8. The rotation of the coupling body 11 towards the closed position is no longer inhibited by the motor 8. The coupling body 11 can thus rotate freely about its rotational axis 10. For this purpose, the coupling body 11 is suspended by means of ball bearings (not shown). The return element 7 can relax - following the return force. Here, the return element 7, designed as a spiral spring, winds up. The winding leads to an equally sudden pulling of the push and / or pull element 17 towards the return element 7, whereby the movable bending element 4 is displaced relative to the fixed bending element 5. This results in the Fig. 7 shows the curved closed position of the gripper arm 2.

[0066] The gripper arm 2 can then be moved back into the pre-tensioned opening position according to Fig. 8. For this purpose, the coupling elements 12 are moved radially outward into the gear 13 by means of the actuator 14 and are accordingly brought into operative connection with the motor 8. When the motor 8 rotates, the coupling body 11 rotates. The motor 8 can thus cause the coupling body 11 to rotate about the rotation axis 10, whereby the tensioning means 16 is wound onto the coupling body 11.

[0067] The coupling body 11 carries on its circumferential surface a tensioning device 15, which is designed here as a winding device and can wind the tensioning means 16 onto the circumferential surface of the coupling body 11. LIST OF REFERENCE SYMBOLS 1 gripping device 2 gripper arms 3 Actuating device 4 Bending element 5 Bending element 6 spacer element 7 Reset element 8 Engine 9 Coupling device 10 Rotation axis 11 Coupling body 12 Coupling element 13 gearboxes 14 Actuator 15 clamping device 16 clamping devices 17 Shear and / or tension element 18 aircraft 19 Hull 20 Initial facility 21 distance 22 Sensor device 23 objects 24 Control device 25 Guide device 26 Gear element

Claims

[1] Gripping device (1) with at least two gripping arms (2) which can be moved towards one another from an open position into a closed position, and at least one actuating device (3) for moving the gripping arms (2), wherein each gripping arm (2) has two bending elements (4, 5) arranged in a wedge-shaped manner relative to one another and extending in a main direction, and at least one spacer element (6) arranged therebetween and oriented transversely to the gripping arm (2), wherein the bending elements (4, 5) are connected to one another in a force-transmitting manner at their distal ends with respect to the main direction and are spaced apart from one another at their proximal ends with respect to the main direction, wherein at least one of the bending elements (4, 5) is displaceable by means of the actuating device (3) with respect to the main direction relative to the other bending element (4, 5) in order to effect a curvature of the gripping arm (2) in the closed position, characterized bythat the actuating device (3) has a restoring element (7) which can be prestressed to a restoring force for applying force to the displaceable bending element (4, 5) in the direction of the closed position of the associated gripping arm (2), a motor (8) which prestresses the restoring element (7) to the restoring force and a coupling device (9) for coupling the restoring element (7) to the motor (8) for the open position of the gripping arm (2) and for decoupling the restoring element (7) from the motor (8) for the closed position of the gripping arm (2). [2] Gripping device (1) according to claim 1, wherein the return element (7) is a spring element, in particular a constant force spring, particularly preferably a spiral spring. [3] Gripping device (1) according to claim 1 or 2, wherein the coupling device (9) has a coupling body (11) rotatable about a rotation axis (10) with radially displaceably mounted coupling elements (12) which are designed to establish a mechanical operative connection to the motor (8) and are displaceable relative to the coupling body (11) by means of an actuator (14). [4] Gripping device (1) according to claim 3, characterized by that the gripping device (1) has a transmission (13), particularly preferably a gear transmission, in mechanical operative connection between the coupling device (9) and the motor (8). [5] Gripping device (1) according to one of the preceding claims, wherein the coupling device (9), in particular the coupling body (11) rotatable about the rotation axis (10), has a tensioning device (15), in particular a winding device, for pre-tensioning the return element (7) and / or for pre-tensioning a tensioning means (16) connected to the return element (7). [6] Gripping device (1) according to one of the preceding claims, wherein a pushing and / or pulling element (17) acts on the displaceable bending element (4, 5) of the gripping arm (2), which is in mechanical operative connection with the return element (7) of the actuating device (3). [7] Gripping device (1) according to one of the preceding claims, wherein the bending elements (4, 5) and / or the spacer element (6) of the gripping arm (2) are at least partially made of an elastic plastic, in particular of a carbon fiber reinforced plastic (CFRP). [8] Aircraft (18), in particular unmanned aircraft (18), having a fuselage (19) and a drive device (20) arranged on the fuselage (19) for moving the aircraft (18) through an environment, characterized by a gripping device (1) according to one of the preceding claims. [9] Aircraft (18) according to claim 8, wherein the gripping device (1) is arranged on the fuselage (19) in a usual orientation of the aircraft (18) during movement such that the gripping device (1) can be opened upwards. [10] Aircraft (18) according to claim 8 or 9, wherein the gripping device (1) is arranged on the fuselage (19) such that the proximal ends of the gripping arms (2) have a distance (21) of less than 100 mm, in particular of less than 50 mm, particularly preferably of less than 25 mm, from the fuselage (19). [11] Aircraft (18) according to one of claims 8 to 10, wherein the gripping device (1) is assigned a sensor device (22) for detecting an object (23) to be gripped and a control device (24) for operating the actuating device (3) in dependence on a detection signal of the sensor device (22).

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