Clamping gripper

Abstract

Clamping gripper (20) having at least two base surfaces on which at least one gripping jaw (10) is arranged such that the gripping jaws (10) are arranged on the clamping gripper (20) in such a way that each gripping jaw (10) is movable in a gripping direction for gripping an object (40), wherein the gripping jaws (10) each further have a membrane (7) which, together with the base area, defines an internal volume of the gripping jaw (10) and thus forms a filling area (3) between the membrane (7) and the base area, wherein the filling area (3) is partially filled with a filling material (11), wherein the base surface is part of a base body (34) in which a pressure fluid guide (32) is formed and wherein the base body (34) has a compressed air connection (31), characterized in that that a filter element (8) is arranged between the base surface and the membrane and is attached to the base body (34) by means of screws (5'). that the membrane (7) is held by means of a fastening element (15) and screws (5) penetrate the fastening element (15) and the membrane (7) and are screwed into the filter element (8).

Description

[0001] The invention relates to a clamping gripper, a retrofit kit for a gripper jaw for a clamping gripper, and a robot. The invention also relates to a use thereof and a method for gripping.

[0002] Clamping grippers are well known in the prior art. They are used to perform industrial gripping tasks for various and diverse objects. Document US 10,661,446 B2 discloses a robot with a clamping gripper in the form of a gripping finger, capable of lifting geometrically diverse objects. For this purpose, at least one membrane filled with granules is brought into contact with an object, and the membrane's outer contour adapts to the object, thus enabling it to grip. A similar concept is described in US 2010 / 0217436 A1, which presents a corresponding gripper mounted on a vehicle. However, the solutions provided are considered unsatisfactory, particularly for handling and gripping delicate products such as fruits and vegetables during sorting, order picking, and / or quality control.

[0003] WO 2014 / 066 753 A1 discloses a clamping gripper in which the gripping fingers are asymmetrically arranged in a hand mechanism. This solution is also not considered satisfactory for gripping delicate objects.

[0004] German patent application DE 11 2011 101 331 T5 discloses a passive universal gripper filled with a granular material enclosed in an elastic membrane. By applying positive and negative pressure, the gripper can quickly grasp and place a variety of objects. However, this solution is unsuitable for delicate objects, particularly the aforementioned fruits and / or vegetables, as pressing the membrane against the object in the direction of its weight can cause pressure marks.

[0005] A vacuum suction gripper is known from WO 2019 / 028 242 A1, featuring a plate that creates a vacuum for picking up objects, such as meat. This solution is considered unsuitable for delicate products and is not geometrically independent. Such plates can also be supplemented with gripping fingers, as shown in DE 20 2020 000 692 U1, but this does not resolve the aforementioned problems. Furthermore, vacuum suction grippers generally pose hygiene risks in the food sector due to the potential for product residue to be sucked in.

[0006] US patent 10,195,746 B2 discloses a gripper with, in particular, three gripping fingers, in which each gripping finger is movable at several points, like the fingers of a human hand. However, the protection of the objects being gripped is considered unsatisfactory. Furthermore, the delicate construction of the fingers can create dead spaces and / or weak points that can trap product residue that is difficult to remove.

[0007] So-called soft grippers, also known as flexion-finger grippers, are known from US patent 10,889,004 B2. These grippers change their shape under pressure, thus enabling the grasping of objects. However, their manufacture, geometry, and the space-consuming flexion movement are considered cumbersome and difficult to use. Other forms of soft grippers are known from US patents 11,090,818 B2, EP 3,479,974 A1, CA 2,981,894 A1, and US patent 2019 / 0168,398 A1, but these do not overcome the aforementioned difficulties and problems.

[0008] The clamping grippers provided in the prior art all exhibit problems with gripping objects, require three or more fingers and a large footprint (e.g., in three directions), are cumbersome and complicated to manufacture and handle, are expensive to produce, and are inflexible in terms of application. From JP H06-206 622 A, a gripping device with deformable membrane gripping elements is known. The filling material of the membrane gripping elements is the size of ping-pong balls. When applied to an object, air is extracted from the membrane gripping elements.

[0009] The invention aims to structurally and functionally improve a clamping gripper, as described above, in order to better grip particularly delicate objects such as fruits and vegetables and / or to improve general handling. Furthermore, the invention aims to enable a resource-efficient transition and reduce the costs associated with this transition. It also aims to improve usability and to make the use of robots more flexible and simpler. Finally, the invention aims to improve the cleaning of the clamping gripper, especially when used for food handling and order picking.

[0010] The problem is solved by a clamping gripper having the features of claim 1. Furthermore, the problem is solved by a retrofit kit having the features of claim 7, and by a robot having the features of claim 8. In addition, the problem is solved by a gripping method according to claim 9. Advantageous embodiments and / or further developments are the subject of the dependent claims.

[0011] In summary, and in other words, the invention provides in particular a clamping gripper having at least two base surfaces on which at least one gripping jaw is arranged such that the gripping jaws are arranged on the clamping gripper in such a way that each gripping jaw is movable in a gripping direction for gripping an object, wherein the gripping jaws each further have a membrane that delimits an internal volume of the gripping jaw with the base surface and thus forms a filling area between the membrane and the base surface, wherein the filling area is partially filled with a filling material, wherein the membrane forms a shape and a filling area and wherein the filling area is filled with filling material in such a way that a center of gravity axis is formed.and wherein the center of gravity axis of the gripping jaw coincides with the gripping direction axis to form a center of gravity gripping axis, and wherein the membrane has at least one surface point in the gripping direction that projects further from the base surface than the other surface points of the membrane, and wherein the center of gravity gripping axis passes through this point. This makes it possible to grip even delicate objects, especially without leaving pressure marks, for example on organic materials such as fruits and vegetables. Furthermore, this allows for a deeper grip and higher form-fit connections.

[0012] In accordance with the claims, a clamping gripper is designed, in particular as a gripping unit with at least or at most, or exactly two, robot gripping fingers. The design with only or exactly two gripping fingers or robot gripping fingers has the advantage that the objects to be gripped, for example on a conveyor belt, only need to be brought into a one-dimensionally disordered track. The objects to be gripped pass, for example, on the conveyor belt between the two gripping fingers or robot gripping fingers and / or gripping jaws. The distance between the objects to be gripped in the direction of flow is not significant. The robot clamping gripper can, in particular, be designed such that at least or at most, or exactly two, in particular parallel, gripping fingers can move towards each other, for example by activating a gripping kinematic mechanism. The direction of movement for gripping, in particular, forms a gripping direction axis.In particular, it is provided that the gripping direction axis of the at least or at most, or exactly, two gripping jaws or robot gripper fingers spans a plane that is, in particular, parallel to a horizontal plane, at least in a gripping state and / or at least in a state in which the clamping gripper is (maximally) open. It can also be advantageous if the two gripping axes of the two gripper fingers coincide on a common axis. In particular, the arrangement and design of the clamping gripper can be such that the gripping direction axis, as well as the center of gravity axis, runs in a plane normal to the base of the gripper finger of the clamping gripper. This has the particular consequence that the gripping jaws are movable in a horizontal plane.

[0013] The filler material can consist of granules, sand, and / or a fluid. This filler material has the characteristic that it undergoes a phase change when subjected to pressurized fluid, i.e., it loosens under pressure and hardens under negative pressure.

[0014] A gripper jaw can be, in particular, a filling area (also referred to as a filling chamber, filling volume, or similar) largely enclosed by a membrane, except for its base, for receiving the filling material. The gripper jaw can be pressurized with a fluid, such as compressed air, which releases the granules. Closing the gripping mechanism, especially by bringing opposing gripping fingers together, results in the membrane (partially) enclosing the object to be gripped. The membrane conforms to the contours of the object, and the granules within the filling volume are forced back to allow the object to be grasped. Therefore, the filling area is not completely filled with granules, and in a free, non-gripping state, there is a cavity that is not filled with material.This allows the membrane to retract and adapt to the object. By extracting the fluid, the filling material can harden again, resulting in a form-fitting grip.

[0015] Furthermore, the filling material can be packed in the filling area and the filling area shaped by the membrane in such a way that a center of gravity axis, positioned in space by the robot arm, is always located in a horizontal plane, especially during repositioning of the gripper. Here, "at all times" can be understood to mean that deviations from this orientation are only possible during short-term high accelerations, and that the filling material is not redistributed when no object is being gripped. In particular, more than 90% of the movement (time domain), and furthermore, more than 95%, and even more than 99%, takes place in a horizontal plane as described above.This enables a smooth robot arm movement, thus improving handling and safety. The center of gravity axis is specifically the axis that carries the centers of gravity of the filling material in the planes perpendicular to this center of gravity gripping axis and the filling material arranged therein. According to the invention, the filling area is filled with filling material in such a way that the gripping direction axis, the surface normal on the base of the gripper fingers of the clamping gripper through a point on the membrane furthest from this point, and the described center of gravity axis coincide. Because the internal volume of the gripper jaw is only partially filled, not the entire internal volume contributes to the formation of the center of gravity. The external shape of the gripper jaw can also be modified so that the center of gravity axis is shifted, for example, compared to gripper jaws from the prior art.The design of the center of gravity axis allows the gripping objects to be grasped at the center of gravity, for example even if the diameter of the objects to be gripped is smaller than the diameter of the membrane, and / or improves and / or enables the handling of the robot control, even with smaller / flatter objects to be gripped and / or higher accelerations.

[0016] Additionally, a gripping direction axis can be formed, in particular, by the degrees of freedom of movement of the clamping device or gripper, and further, in particular, by the degrees of movement of the gripping jaws on the gripping fingers. This gripping direction results, in particular, from the kinematic movement of the gripping process, whereby the at least or at most or exactly two gripping fingers, and thus the at least or at most or exactly two gripping jaws, are moved towards each other, in particular in such a way that the inclination of the gripping direction axis does not change. Furthermore, in particular, the gripping direction axis and the center of gravity axis coincide to form what is here called the center of gravity gripping axis.This ensures that the center of gravity axis and the gripping axis do not change from the start of the gripping process, particularly from the initial movement of the at least two gripping jaws towards each other, until the end of the gripping process, i.e., until the object is firmly grasped and lifted. It can be particularly advantageous if the gripping direction axis, the center of gravity axis, or the center of gravity gripping axis are designed as a surface normal to the base surface. This also allows for a deeper grip on the object and higher positive locking forces.

[0017] Alternatively or additionally, it can be advantageous if the center-of-gravity gripping axis is designed, through the appropriate shape of the gripping jaws and the appropriate filling of the filling area, such that the clamping gripper, particularly in the form of a parallel clamping gripper, enables the picking up and gripping of an object at the level of its center of gravity. In this case, the center-of-gravity axis of the gripping jaws, the gripping axis, and the center of gravity of the object can coincide.

[0018] The membrane is made of a particularly soft and / or elastic material, such as rubber, silicone, latex, or other elastomers. The membrane is designed so that its shape and contour adapt to the object being gripped when it comes into contact with it during the gripping process. The material used also depends on the specific application. For example, the food industry may have special requirements, such as sterilizability or washability, as well as material stability and stress resistance, compared to other applications where, for instance, less stringent requirements regarding compatibility and health are necessary. Similar requirements may apply to the filling material to prevent the food product from becoming unusable for sale if a gripping jaw is damaged.

[0019] In particular, the gripping axis, the center of gravity axis, and the center of gravity gripping axis all pass through a point projecting furthest forward from the base surface (surface front point). This point can also serve as the initial contact point with the object being gripped, ensuring that the object is always gripped at its center of gravity (the gripping jaws).

[0020] In particular, the at least one surface front point is also the center of gravity, especially of the entire gripper jaw or of an entire base body with the gripper jaw attached to it. The center of gravity gripping axis described above also passes through this center of gravity. Furthermore, the initial contact with a gripped object occurs at this surface front point. This means that the gripped objects are picked up at the center of gravity of the gripper jaws, which improves the gripping and the movement dynamics of the robot gripper finger and / or the robot gripper arm.

[0021] In particular, the center of gravity of at least one of the gripper jaws and / or the object being gripped falls on the center of gravity gripping axis. Furthermore, the two gripper jaws and / or the robot gripper fingers are positioned opposite each other in such a way that the two center of gravity gripping axes of the two gripper jaws coincide. This allows for the formation of a parallel gripper in which the two gripper fingers are parallel to each other. This enables balanced gripping, which further improves handling.

[0022] According to one embodiment of the invention, the underlying problem of the invention is solved in particular by a clamping gripper, wherein at least or at most or exactly two gripping fingers are formed, each having at least one base surface on which the respective at least one gripping jaw is arranged, or wherein exactly two gripping fingers, each with a gripping jaw, are designed as parallel gripping fingers, and / or wherein the center-of-gravity gripping axis of the first gripping jaw coincides with the center-of-gravity gripping axis of the second gripping jaw. This allows for balanced gripping, which further improves handling.

[0023] In particular, in one embodiment, gripping fingers according to the invention can also be combined with gripping fingers from the prior art if this is useful for the application, or if it is necessary to quickly switch between different types of gripping fingers.

[0024] Alternatively, a parallel gripper is designed in which the two gripping jaws and / or robot gripping fingers are parallel to each other. The gripping direction is defined by the direct and shortest connection between the two gripping jaws. The gripping fingers can move towards each other symmetrically around their central axis / plane. Alternatively, the gripping fingers can also be designed to move independently of each other. Furthermore, the robot gripping fingers, and thus the clamping gripper, are designed in such a way that the gripping fingers do not bend during gripping. This also means that the gripping jaws do not perform a bending or rotational movement to execute a gripping motion. In particular, "parallel" is to be understood as meaning that the planes spanned by the respective base surfaces are parallel to each other.

[0025] According to one embodiment of the invention, the underlying problem of the invention is solved in particular by a clamping gripper, wherein the base surface is at least partially perforated for pressurizing the partially filled filling area and / or for retaining the filler in the filling area and / or wherein a separately formed filter element is associated with the perforation of the base surface, for pressurizing the partially filled filling area and / or for retaining the filler in the filling area. This improves gripping and reduces or completely prevents contamination in the pressurizing fluid guide, thus preventing it from being reintroduced into the gripper jaw, for example, during repeated pressurization for further gripping operations.The service life of the clamping gripper is also increased, as no incorporated filler material parts clog or otherwise damage the pressure fluid guide and any pumps.

[0026] The gripper jaw can be pressurized with a fluid, particularly with a pressure fluid pulse, to loosen the filler, granules, or sand material, thus enabling and improving gripping. After the object being gripped is enclosed by the membrane, as described elsewhere, the pressure fluid is extracted, creating a vacuum to harden the filler, granules, or sand material. This ensures a secure fit and holds the object firmly in place. A pressure fluid pulse can then be used to loosen the filler material again, thus releasing the grip.

[0027] Compressed air is the primary pressure fluid used, but other gases or gas mixtures can also be employed. Alternatively, pressurization with a liquid or liquid mixture may be used. The choice of fluid depends primarily on the application and / or its specific requirements.

[0028] The opening can be achieved by creating a recess in a 3D printing process, or by a CNC milling process, or by an injection molding process.

[0029] According to one embodiment of the invention, the underlying problem of the invention is solved in particular by a clamping gripper, wherein the gripping jaw is designed such that a top surface of the gripping jaw is formed in a gripping position and / or in a rest position relative to the center of gravity gripping axis above the center of gravity gripping axis and that a bottom surface of the gripping jaw is formed in a gripping position and / or in a rest position relative to the center of gravity gripping axis below the center of gravity gripping axis, wherein the top surface and bottom surface differ and / or wherein the top surface and bottom surface are not symmetrical to each other, and / or wherein the top surface and bottom surface are not symmetrical to a plane through the center of gravity gripping axis and / or wherein the top surface and bottom surface are not point-symmetrical to the points of the center of gravity axis or a central axis.This allows the gripping jaw to be positioned lower in the vertical direction of the gripping object and / or gripping to take place at the center of gravity, which can also improve the form-fitting gripping, for example through a deeper and / or longer deformation.

[0030] The term "central axes" here refers to any possible axes of symmetry that pass approximately through the center of the gripping jaw. The same applies, in particular, to a corresponding plane. Symmetry with respect to a central plane that (conceptually) divides the gripping jaw into two parts is not (necessarily) present. However, bilateral symmetry may exist.

[0031] According to one embodiment of the invention, the underlying problem of the invention is solved in particular by a clamping gripper, wherein the upper surface is curved and / or hemispherical and the lower surface is flattened. This allows the gripping jaw to be positioned lower in the vertical direction of the object being gripped and / or enables gripping at the center of gravity, thereby also improving the positive locking grip.

[0032] In this case, the membrane cannot form a hemisphere; rather, its upper surface approximates a hemisphere, and its lower surface is flattened in such a way that, compared to a hemisphere, the overall shape is flattened and shortened. Specifically, the flattening of the gripping jaw on its lower surface leads to a raising of the center of gravity axis when the filling area is partially filled, compared to a hemispherical gripping jaw with identical filling and an identical upper surface shape that is mirrored to a central plane.

[0033] According to one embodiment of the invention, the underlying problem of the invention is solved in particular by a clamping gripper, wherein the base surface is part of a base body that is designed separately from the rest of the clamping gripper and / or the gripping finger, and / or wherein a pressure fluid guide is formed in the base body. This allows the base body to be manufactured separately, for simple and resource-saving retrofitting, as well as for corresponding shape optimization adapted to the respective requirements.

[0034] The base body can be manufactured using CNC milling, injection molding, or 3D printing (an additive manufacturing process). In particular, the base body is designed to be compatible with a standard, commercially available robot arm or gripper finger, simplifying retrofitting and saving resources. This connection can be achieved using standard screws.

[0035] According to an independent aspect, the object of the invention is particularly solved by a retrofit kit for a gripper jaw for a clamping gripper or for a clamping gripper according to the invention, as described elsewhere, wherein the kit comprises a fastening element, a membrane configured to be arranged on a base surface of the clamping gripper and / or a gripper finger and / or a base body in such a way as to form and delimit an internal volume with the base surface and thus to form a filling area between the membrane and the base surface as a filling area, and a filling material to partially fill the filling area, wherein the fastening element is configured to be arranged over the membrane in a section area in order to position the membrane between the fastening element and the base surface.This simplifies retrofitting, reduces resource requirements, and improves cleaning of the gripper jaws. The retrofit kit can include the base body and / or the filter element. The base body and / or filter element can be designed as described above and / or below.

[0036] The fastening element and / or the base body and / or a filter element that can be arranged on the base body can be manufactured using CNC milling, injection molding, or additive 3D printing. The shape can be adapted to the requirements. The fastening element can be attached to the membrane and / or the filter element and / or the base surface, particularly as part of a separate base body, by screws and / or pins. The corresponding elements feature pins, screws, plug connectors, eyelets, feedthroughs, and openings to connect the elements, in particular by plugging and / or screwing them together.

[0037] The term "internal volume" here and elsewhere refers specifically to the volume bounded by the membrane and the base, and the fluid-tight sealing of this interior space, thus enabling pressurization, as described elsewhere. In particular, a retrofit kit (also referred to as a retrofit system) may feature a sandwich construction in an edge area, where the membrane is enclosed by a mounting element and a base body and / or a filter element to hold it in position. Furthermore, a sealing element may also be provided between the filter element and the base body and / or between the membrane and the base body. This increases the tightness of the retrofit kit, prevents fluid from escaping into the food area, and / or reduces the risk of damage.

[0038] For further specification and description of the retrofit kit, reference can be made to the definitions relating to the clamping gripper and / or the robot. For the sake of a concise description, unnecessary repetitions are omitted here.

[0039] According to one embodiment of the invention, the underlying problem of the invention is solved, in particular, by a retrofit kit, wherein the membrane, in its fully assembled state, forms a shape and a filling area, and wherein the filling area is filled with filling material in such a way that a center of gravity axis is formed, and wherein the center of gravity axis of the gripping jaw coincides with the gripping direction axis to form a center of gravity gripping axis. Furthermore, and in particular, the membrane can have at least one surface point in the gripping direction that projects further from the base surface than the other surface points of the membrane, and wherein the center of gravity gripping axis passes through this point. This makes it possible to grip even delicate objects, especially without leaving pressure marks, for example, on organic materials such as fruits and vegetables.Furthermore, this allows for a deeper grip and higher degree of positive locking. It also facilitates cleaning.

[0040] According to one embodiment of the invention, the underlying problem of the invention is solved in particular by a retrofit kit, wherein a filter element is arranged between the base surface and the membrane in a fully assembled state, for retaining the filling material from a pressure fluid guide opening in the base surface. This improves purity and cleanliness. Furthermore, it facilitates cleaning.

[0041] Furthermore, a sealing element can be arranged between the base and the filter unit. This increases the tightness, even when subjected to pressure, particularly above 1 bar, and especially above 2 bar, and even more specifically above 3 bar. Pressure can also be applied at lower pressures, for example below 1 bar, particularly below 0.5 bar, or even below 0.1 bar. The pressure can also be between 0.01 and 0.1 bar. The pressure can be determined based on the membrane, for example, its thickness, strength, and / or material properties. For example, the pressure can be increased with thicker and / or stronger membranes. These pressure definitions also apply elsewhere in the invention as a whole and are not limited to the present embodiment.

[0042] According to an independent aspect of the invention, the problem is solved in particular by a robot comprising a clamping gripper according to the invention.

[0043] The robot can be mobile or stationary. In particular, the robot has at least one gripper arm with a clamping gripper according to the invention. The robot can be controlled and configured such that the center-of-gravity gripping axis runs predominantly or always in a horizontal plane. While the clamping gripper can be rotated, this rotation preferably also takes place in a horizontal plane, meaning the axis of rotation is perpendicular to such a horizontal plane, and in particular not parallel to it. This prevents or minimizes the displacement of the filler material in the partially filled area. With a robot according to the invention, it is possible, especially when using a parallel gripper, for the center-of-gravity gripping axis to overlap with the center of gravity of the object being gripped, thus enabling the objects to be gripped at the level of their center of gravity.This eliminates the need for the laborious process of separating delivered objects; instead, they can be gripped directly on a conveyor belt. This simplifies the gripping process and opens up new application areas.

[0044] Here, the previously given definitions can also be used for a specification, and for reasons of good readability and conciseness of the invention presentation, mere repetitions are avoided.

[0045] According to another aspect, the clamping gripper according to the invention can be mounted and / or fixed in a stationary position, for example, on a stationary device. In contrast to mounting the clamping gripper on a robot or robot arm, here the clamping gripper itself is not moved, except for its actual gripping movement. The clamping gripper can be designed as a stationary fixed clamp. This allows the object to be held and / or kept in position by means of the clamping gripper. For example, a person or a robot can clamp an apple and cut out brown spots, or clamp an avocado to remove the peel. The guidance does not necessarily have to be provided by a robot.

[0046] According to an independent aspect of the invention, the problem is solved in particular by using a clamping gripper according to the invention, a retrofit kit according to the invention or a robot according to the invention.

[0047] The application can be further specified here by the features of the clamping gripper, the retrofit kit, and / or the robot. Repetition is omitted here for the sake of brevity.

[0048] According to an independent aspect of the invention, the problem is solved in particular by a method for gripping an object, wherein a clamping gripper is moved relative to an object such that the object comes to rest relative to the gripping fingers of the clamping gripper in such a way that gripping is possible, wherein the clamping gripper according to the invention in particular has at least two base surfaces on which at least one gripping jaw is arranged such that the gripping jaws are arranged on the clamping gripper such that each gripping jaw is movable in a gripping direction for gripping an object, wherein the gripping jaws each further have a membrane which limits an internal volume of the gripping jaw with the base surface and thus forms a filling area between the membrane and the base surface, wherein the filling area is partially filled with a filling material.wherein the membrane forms a shape and a filling area such that the filling area is filled with filling material such that a center of gravity axis is formed, and wherein the center of gravity axis of the gripping jaw coincides with the gripping direction axis to form a center of gravity gripping axis, and wherein the membrane has at least one surface point in the gripping direction that projects further from the base surface than the other surface points of the membrane, and wherein the center of gravity gripping axis passes through this point, wherein the method comprises the following steps: moving the clamping gripper to the gripping object such that the gripping object comes to rest at the height of the center of gravity gripping axis, at least temporarily applying pressure to the filling area, in particular to loosen the filling material,The gripping mechanism involves the kinematic closing of the gripping fingers with gripping jaws around the object being gripped; pressure reduction to harden the filling material during a form-fitting grip on the object by the gripping jaws; and movement of the clamping gripper. This facilitates and improves handling. The temporary pressurization of the filling area can be at least a pressure pulse, for example, using compressed air. The temporary pressurization can include maintaining a defined pressure. The temporary pressurization can also include venting to atmospheric pressure. Here, too, the previously given definitions can be used for further specification, and for the sake of readability and conciseness of the invention description, mere repetitions are omitted. Releasing the gripped object essentially takes place in the reverse order, whereby, for example, a loosening step is not necessarily required as a final step.

[0049] Exemplary embodiments of the invention are described in more detail below with reference to the figures, which show schematically and by way of example: Fig. 1A a comparison between an embodiment of a gripping jaw according to the invention and a hemispherical gripping jaw, represented by overlap; Fig. 1B an embodiment of a gripping jaw according to the invention; Fig. 1C a parallel gripper with embodiments of the gripping jaws according to the invention; Fig. 2 a cross-section through an embodiment of a gripping jaw according to the invention; Fig. 3 an exploded view of a modular system (retrofit kit) of an embodiment of a gripping jaw according to the invention.

[0050] The term "may" refers in particular to optional features of the invention. Accordingly, there are also further developments and / or embodiments of the invention that additionally or alternatively include the respective feature(s).

[0051] From the combinations of features disclosed herein, isolated features can also be selected as needed and, after dissolving any structural and / or functional relationship that may exist between the features, used in combination with other features to define the subject matter of the claim. The order and / or number of steps of the method can be varied.

[0052] Fig. Figure 1A shows a gripping finger 30 according to the invention, with a gripping jaw 10 according to the invention, which overlaps a hemispherical gripping jaw 4 shown schematically (in Fig. 1A (indicated by a dashed outline) is compared. It becomes clear that the gripping jaw 10 according to the invention, and thus also the entire gripping finger 30, is shorter than the gripping finger with gripping jaw 4. The membranes 7 differ in that the upper surface shape remains identical up to the furthest forward projecting point, the front point 9, while the lower surface shape has a flattening, also referred to as the bearing area 6 (bearing area for the filling material). This bearing area leads to the aforementioned shortening of the gripping finger 30, but also to an upward shift of the center of gravity axis 13 compared to the center of gravity axis 14 in the prior art, when both are filled with the same amount of filling material (not shown). However, complete filling of the filling area 3 is not intended, as otherwise the filling material cannot be displaced when an object is gripped.This creates a cavity 12 (see . Fig. 2) when the filling area 3 is filled with filling material. The filling area is connected to a compressed air connection 31 via a pressure fluid guide, here a compressed air guide 32, as shown in the partial section of the base body 34. The filling area 3 is fluidically connected to the compressed air connection 31; however, the granules 11 (not shown) in the filling area 3 are kept away from the compressed air guide 32 by a filter element 35 to prevent contamination of the compressed air guide 32. This filter element 35 is connected to the gripper finger 30 via screws 5'. In the embodiment shown here, this gripper finger is manufactured by a 3D printing process and is connected to a clamping gripper 20, for example for a robot gripper arm (not shown here), via screws 5''. The membrane is screwed onto the gripper finger 30 by means of a fastening element 15 using screws 5. Fig. 1B is to the Fig. 1A is identical, however, for clarity, the outline of the gripping finger and gripping jaw 4 is no longer shown. Nevertheless, the description is identical and is therefore not repeated here.

[0053] Fig. Figure 1C shows a clamping gripper 20 designed as a parallel gripper 23. The clamping gripper 20 has two gripping fingers 30 with gripping jaws 10 according to the invention. For example, the gripping fingers 30 and / or gripping jaws 10 can be replaced by a retrofit kit 100 according to the invention, as shown in Fig. 3 shown in the exploded view, can be attached, for example, to a parallel gripper kinematic device. As shown in Fig. As shown in Figure 1C, two gripping jaws 10 according to the invention are positioned opposite each other such that their front points 9 are opposite each other and the base surfaces of the gripping fingers 30 or the base body 34 of the gripping fingers 30 are arranged parallel to each other. The gripping object is illustrated here in the form of a pear 40. The two gripping fingers 30 are moved towards each other with the gripping jaws 10, which remain parallel even during the movement and thus move along the center-of-gravity gripping axis 13 in order to come into contact with the pear 40 at the front point 9. The clamping gripper 20 is the Fig. 1C, and in particular its gripper jaws 10, are designed and filled with granules 11 such that when the pear 40 is gripped, its center of gravity lies on the center-of-gravity gripping axis 13. The relative movement of the gripper jaws 10 to the pear 40 is decisive here, not the absolute position in space. Thus, all centers of gravity, both those of the gripper jaws 10 and of the pear 40 (and of any other gripped object), are arranged on a center-of-gravity gripping axis, which can improve the robot's motion dynamics, etc. Furthermore, the gripped object, such as the pear 40 in this example, is not subjected to high pressures during gripping to prevent displacement. This minimizes the risk of damage to the gripped object.The support area 6 also allows for a deeper grip compared to the prior art, since the bilateral shape of the gripper jaw leads to an asymmetry in its vertical direction, meaning that gripping is only possible at the height of the center of gravity. This eliminates the need for prior singulation of the gripping objects, such as the pears 40 in this case. This reduces the costs of use and gripping processes.

[0054] The compressed air connection 31 allows the filling material (not visible) to be loosened with a short burst of compressed air before gripping, resulting in easier and more secure gripping. During gripping, the compressed air is then drawn away through the compressed air line and the compressed air connection 31, causing the granules to harden and thus securing the grip and lifting the bulb. Here, the support area 6 becomes apparent, which shifts the center of gravity axis upwards (compared to the prior art), so that it coincides with the gripping axis 13, which is formed as the surface normal on the base of the gripper finger 30 or base body 34, or alternatively on the base of the filter element 8, and which passes through the front point 9.The sandwich construction in the edge region 52 of the membrane 7, wherein the latter is arranged between the fastening element 15 and the filter element 8 and the filter element is arranged with a seal 51 on the base body 34, is shown in more detail below.

[0055] Fig. Figure 2 shows a cross-section through a base body 34 with a gripping jaw 10 according to the invention, which is formed by the membrane 7 and is screwed onto the filter element 8 and the base body 34 by means of a fastening element 14 and screws 5. A sealing element 15 is arranged between the base body 34 and the filter unit 8. This clearly shows how the filling area 3 is fluidically connected to the compressed air line 32 and the compressed air connection 31 in order to loosen or harden the granules 11 by increasing or decreasing the pressure. Due to the partial filling of the filling area 3 with granules 11, a cavity 12 is formed above the granules, which is unfilled. The granules 11 rest on the support area 6 and are portioned such that the center of gravity gripping axis 13 passes through the front point 9, as described above.The membrane 7 is recognizable in an outer area as edge 52, which is why the retrofit kit 100 results in a sandwich construction in the edge area 52, i.e., in the area of ​​the screws 5. Further features and descriptions of the... Fig. The above applies accordingly and is not repeated here.

[0056] Fig. Figure 3 shows an exploded view of a retrofit kit 100 to illustrate the assembly for retrofitting or converting, for example, a commercially available clamping gripper into a clamping gripper according to the invention. A fastening element 15 is shown, which on its underside (relative to the later center of gravity gripping axis 13, as shown in the Fig.(Explained in sections 1 to 2) is flattened to form the support area 6 and has an arcuate or hemispherical shape on its upper surface. It has a series of screws 5 that pass through corresponding bores. These fit into holes 17 in the membrane 7. Here, too, the underside is flattened towards the support area 6, as described in detail. The filter element 8 with its recesses 35 is attached to the base body 34 by screwing screws 5' into screw holes 18 of the base body 34 above the compressed air duct 32, which is formed as an opening through the base surface. A sealing ring 51 is arranged between the filter unit 8 and the base body 34, but this is not shown here for clarity.The membrane 7 is attached to the filter unit 8 by the screws 5, which pass through the fastening element 15 and the membrane 7 through designated holes and are screwed into the screw holes 16 of the filter unit 8. This results in the sandwich construction described above (at least in the edge 52 of the screws 5). Reference sign 3 Filling area 4. Shape of a hemispherical gripping jaw 5, 5'; 5'' screws 6 printing area 7 Outer membrane of the gripper jaw 8 filter units 9 Front point 10 Gripping jaw 11 granules 12 Cavity 13 Center of gravity gripping axis 14 Center of gravity axis according to the state of the art 15 Membrane attachment 16 screw holes 17 screw holes 18 screw holes 20 clamping grippers 21 screw holes 22 Connecting piece to robot arm 23 parallel grippers 30 gripping fingers 31 Compressed air connection 32 Compressed air routing 34 Basic bodies 35 filter area 40 pears 51 Seal 52 Edge of the membrane

Claims

[1] Clamping gripper (20) having at least two base surfaces on which at least one gripping jaw (10) is arranged such that the gripping jaws (10) are arranged on the clamping gripper (20) in such a way that each gripping jaw (10) is movable in a gripping direction for gripping an object (40), wherein the gripping jaws (10) each further have a membrane (7) which, together with the base area, defines an internal volume of the gripping jaw (10) and thus forms a filling area (3) between the membrane (7) and the base area, wherein the filling area (3) is partially filled with a filling material (11), wherein the base surface is part of a base body (34) in which a pressure fluid guide (32) is formed and wherein the base body (34) has a compressed air connection (31), characterized by , that a filter element (8) is arranged between the base surface and the membrane and is attached to the base body (34) by means of screws (5'). that the membrane (7) is held by means of a fastening element (15) and screws (5) penetrate the fastening element (15) and the membrane (7) and are screwed into the filter element (8). [2] Clamping gripper (20) according to claim 1, characterized by , that the fastening element (15) is flattened on its underside and curved on its upper side, so that the membrane (7) is flattened on its underside and at least approximately hemispherical on its upper side. [3] Clamping gripper (20) according to claim 1, characterized by , that each individual membrane (7) has a surface front point (9) in the direction of grasping which protrudes further from the base surface than the other surface points of the membrane (7). [4] Clamping gripper (2) according to claim 1, characterized by , that the gripping directions of the two gripping jaws (10) are oriented opposite to each other. [5] Clamping gripper (20) according to claim 1, characterized by , that a sealing element (51) is arranged between the base surface and the filter element (8). [6] Clamping gripper (20) according to claim 1, characterized by , that the fill material (11) is a granular or sand material. [7] Jaw retrofit kit (100) for a jaw of a clamping gripper (20) according to claim 1, comprising: - a base body (34) with a compressed air connection (31), a pressure fluid guide (32) and a base surface, - a filter element (8), - a membrane (7), - a fastening element (15), - Filling material (11) for partially filling a filling area (3) formed between the membrane (7) and the base surface, so that the filter element (8) can be attached to the base body (34) by means of screws (5') and the fastening element (15) and the membrane (7) can be attached to the filter element (8) by means of screws (5'). [8] Robot with a clamping gripper (20) according to claim 1. [9] Method for gripping a gripping object (40) by means of a clamping gripper (20) according to claim 3, - wherein the clamping gripper (20) is moved to the gripping object (40) in such a way that the gripping object (40) comes to rest at the level of the surface front point (9), - wherein the filling area (3) is subjected to pressure, at least temporarily, to loosen the filling material (11), - wherein the gripping fingers (30) are closed around the gripping object with the gripping jaws (10), - wherein, during the form-fitting gripping of the gripping object (40), the pressure is reduced to allow the filling material (11) to harden and - whereby the clamping gripper (20) is moved.

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