Pole shoe for a magnetic gripper, and magnetic gripper with pole shoe

Abstract

The invention relates to pole shoe (26, 28) for guiding a magnetic field component of a magnetic gripper (10) to a ferromagnetic workpiece (52) in order to grip the ferromagnetic workpiece (52) by means of the magnetic gripper (10). The pole shoe (26, 28) has: a securing device (30, 32) for securing the pole shoe (26, 28) to a housing (12) of the magnetic gripper (10), an active structure (34, 36) for guiding the magnetic field, and a workpiece contact surface (38, 40) for contacting the ferromagnetic workpiece (52). The workpiece contact surface (38, 40) is a continuous surface.

Description

[0001] Title: Pole shoe for a magnetic gripper and magnetic gripper with pole shoe

[0002] Description

[0003] The invention relates to a pole shoe for a magnetic gripper, as well as a magnetic gripper with such a pole shoe.

[0004] Magnetic grippers typically have a magnet to generate a magnetic field for gripping ferromagnetic workpieces. Pole shoes are often used to guide a portion of the magnetic field to the workpiece to be gripped.

[0005] Magnetic grippers and associated pole pieces for this purpose are known, for example, from DE 20 2019 005 976 U1. These pole pieces each have a plurality of projections and recesses. The plurality of projections of each pole piece form a common workpiece contact surface, i.e., to grip a workpiece, the pole piece rests against the workpiece with several unconnected areas, and the workpiece contact surface is therefore uninterrupted. According to DE 20 2019 005 976 U1, the projections can concentrate the magnetic field near the workpiece contact surface, enabling the destacking of thin sheets.

[0006] The invention is based on the object of providing improved gripping properties for gripping ferromagnetic workpieces using a magnetic gripper, in particular enabling secure and / or gentle gripping of the ferromagnetic workpiece and also solving special gripping tasks such as unstacking metal sheets. The invention solves this problem by a pole piece having the features of claim 1 and by a magnetic gripper having the features of claim 14. Advantageous embodiments and further developments of the invention are set out in the dependent claims.

[0007] A pole shoe according to the invention is suitable for guiding a magnetic field component of a magnetic field of a magnetic gripper to a ferromagnetic workpiece for gripping the ferromagnetic workpiece by means of the magnetic gripper. The pole shoe is designed for use in a magnetic gripper, in particular in that the pole shoe is arranged on a housing of the magnetic gripper such that the magnetic field of the magnetic gripper is guided / directed by the pole shoe to the workpiece to be gripped. The pole shoe has a fastening device, an active structure, and a workpiece contact surface. The fastening device is designed to fasten the pole shoe to the housing of the magnetic gripper. The active structure is designed for magnetic field steering, i.e., steering at least a portion of the magnetic field of the magnetic gripper.In particular, the active structure can be designed to increase the holding force of the magnetic gripper and / or to reduce the depth effect of the magnetic field component. The workpiece contact surface is the surface of the pole piece designed to contact the ferromagnetic workpiece. The workpiece contact surface is therefore the surface of the pole piece designed to bear against the workpiece when gripping the ferromagnetic workpiece (i.e., when the pole piece is connected to a corresponding magnetic gripper).

[0008] The workpiece contact surface is formed as a continuous surface. In particular, the workpiece contact surface is an uninterrupted surface. Further preferably, the workpiece contact surface is formed without holes and / or recesses. The workpiece contact surface can, in particular, be a simply continuous surface.

[0009] In particular, the workpiece contact surface cannot comprise two separate surfaces and / or regions. The design of the workpiece contact surface as a continuous surface can be understood as meaning that any two points on the workpiece contact surface can be connected by a continuous curve, line, or path without leaving the workpiece contact surface. In other words, the continuous curve, line, or path can run within the workpiece contact surface.

[0010] The workpiece contact surface can be flat. This can be useful, since for workpieces of typical dimensions, the contact area for the pole piece is often at least approximately flat. A flat workpiece contact surface is also often useful for unstacking a stack of magnetic sheets or similar. An uneven, e.g., curved, workpiece contact surface, on the other hand, can be useful if the workpiece is to be contacted in a correspondingly uneven, e.g., curved, area.

[0011] Because the workpiece contact surface is designed as a continuous surface, the holding force that occurs when gripping a workpiece can be distributed evenly over a larger area. This allows for a more even pressure distribution on the workpiece, thereby better protecting the workpiece from deformation or damage.

[0012] Furthermore, by designing the workpiece contact surface as a continuous surface, the number of edges that come into contact with the workpiece when gripping it can be reduced, thereby reducing the risk of damage to the workpiece. This can be particularly advantageous for destacking coated sheets, as the continuous workpiece contact surface can reduce or completely prevent the risk of damage to the coating caused by an edge of the pole piece. This allows the pole piece to grip the workpiece both safely and gently.

[0013] The pole piece may be made of a material that has the property of amplifying and / or conducting magnetic fields. The pole piece may be made of a ferromagnetic material, in particular iron, steel, nickel, or cobalt.

[0014] The pole piece is advantageously formed in one piece. However, multi-part designs are also possible, e.g., to simplify assembly. In a design with multiple pole piece components, the pole piece can comprise a ferromagnetic material and a non-ferromagnetic material. In principle, the two materials can be integrally connected to one another, in particular, together forming a monolithic body. However, it can also be advantageous for the two materials to be detachably connected to one another. For example, the non-ferromagnetic material can be detachably and reconnectably attached to the ferromagnetic material.

[0015] The non-ferromagnetic material can be, for example, a plastic, in particular an elastomer. The non-ferromagnetic material can form the workpiece contact surface. Advantageously, the non-ferromagnetic material can protect the workpiece from damage, in particular from scratches.

[0016] For example, the non-ferromagnetic material can be designed as a spacer. The spacer can be designed to define a distance between the workpiece contact surface and the ferromagnetic material, in particular between the workpiece contact surface and the active structure. By defining the distance, the depth effect of the magnetic field component can be determined.

[0017] By varying the distance, the depth effect of the magnetic field component can be adjusted. For example, a plurality of spacers of different thicknesses can be provided, with the depth effect of the magnetic field being adjusted by selecting the spacer with a predetermined thickness.

[0018] The spacer can be designed as an elastomer strip. The elastomer strip can be bonded to the ferromagnetic material of the pole piece, for example, by means of an adhesive bond. Advantageously, the elastomer strip can absorb higher transverse forces, which can occur, for example, during movement of the pole piece and a gripped workpiece. This allows for higher process speeds and system throughputs.

[0019] The pole piece is particularly intended and configured to be magnetically coupled to a magnet of the magnetic gripper. Directing or guiding the magnetic field component of the magnetic gripper to the ferromagnetic workpiece for gripping the ferromagnetic workpiece by means of the magnetic gripper can be understood as meaning that a portion of the magnetic field of the magnetic gripper is deflected, reshaped, and / or concentrated in certain regions by and / or by means of the pole piece. In particular, the guided portion of the magnetic field can be a portion of the magnetic field required or desired for gripping the workpiece. The magnetic field component can be guided by the pole piece if a magnetic field line of the magnetic field runs within the pole piece and exits the workpiece contact surface.

[0020] Gripping the workpiece can be understood as the magnetic field component guided by the pole piece being coupled into the workpiece in such a way that the workpiece experiences a magnetic force due to the coupled magnetic field component, which presses the workpiece against the pole piece. The magnetic force can then be greater than the weight of the workpiece. In other words, the ferromagnetic workpiece can be gripped by the magnetic gripper if the magnetic field component guided by the pole piece pushes or presses the workpiece against the workpiece contact surface.

[0021] The ferromagnetic workpiece can be made of iron or steel. The workpiece can be a sheet or a material panel. In particular, a width and / or a length of the workpiece can be more than five times, in particular ten times, the thickness of the workpiece. The thickness of the workpiece can, for example, be in a range from 0.5 mm (millimeters) to 5 cm (centimeters), in particular 0.5 mm to 5 mm. The workpiece can have a coating.

[0022] The fastening device can have at least one through-hole for receiving a fastening screw to establish a screw connection between the pole piece and the housing of the magnetic gripper. The through-hole can be designed as a countersunk bore. Additionally or alternatively, the fastening device can have at least one thread for establishing a screw connection between the pole piece and the housing of the magnetic gripper.

[0023] The fastening device can have a receptacle for receiving a threadlock for securing a fastening screw inserted into the fastening device. The receptacle can be designed as a countersunk hole. The threadlock can be designed as an O-ring. If the pole piece is attached to the magnetic gripper, the receptacle for the fastening device can be arranged on a side of the pole piece that faces toward or away from the magnet of the magnetic gripper.

[0024] The effective structure can be formed by a geometric design of the pole piece for the targeted guidance of the magnetic field lines. The geometric design can have at least one bevel and / or at least one rounded portion. The geometric design can be formed by the introduction of shoulders, holes, recesses, and / or steps.

[0025] The active structure can be formed by a material accumulation and / or a material reduction. The active structure can be formed by a geometric shape and / or by a microstructure of the pole piece. The active structure can, for example, have a number of channels, a number of slots, a number of depressions, and / or a number of elevations. The active structure can be designed as a periodic structure.

[0026] The active structure may be unsuitable for contacting the workpiece. The active structure may, in particular, be designed solely to increase the holding force of the magnetic gripper and / or to reduce the depth effect of the magnetic field component. Preferably, the active structure neither forms the workpiece contact surface nor comprises the workpiece contact surface.

[0027] The active structure can influence the path of the magnetic field component in the pole piece. The active structure can direct or focus the path of the magnetic field component in a specific direction. The active structure can be designed to guide the magnetic field component from the magnet of the magnetic gripper to the workpiece contact surface.

[0028] The active structure can serve to direct the magnetic field component, which in particular can also comprise (at least regional) focusing. By focusing the magnetic field component, the holding force of the magnetic gripper can be increased. By directing the magnetic field component, a depth effect of the magnetic field component on the workpiece can be reduced. In particular, the active structure can reduce the depth effect of the magnetic field component on the workpiece by directing the magnetic field component in such a way that a distance of the magnetic field lines of the magnetic field component after the magnetic field component emerges from the workpiece contact surface to the workpiece contact surface is smaller than a distance of the magnetic field lines of the magnetic field component after it emerges from the workpiece contact surface to the workpiece contact surface without the active structure.

[0029] The active structure, in particular an orientation of the active structure, can be designed to optimize an orientation and / or a flow of the magnetic field component for gripping the workpiece.

[0030] The active structure can be arranged between the fastening device and the workpiece contact surface.

[0031] The active structure can extend toward the workpiece contact surface. In particular, the active structure can extend from an end or side of the pole piece opposite the workpiece contact surface to the workpiece contact surface. Alternatively, the active structure can extend from the fastening device to the workpiece contact surface.

[0032] The active structure can extend to a contact area of ​​the pole piece. In particular, the active structure can extend from the end or side of the pole piece opposite the contact area to the contact area. Alternatively, the active structure can extend from the fastening device to the contact area. The contact area can be limited by the workpiece contact surface. The contact area can extend from the workpiece contact surface to a maximum of 5 mm, preferably 4 mm, 3 mm, 2 mm, or 1 mm, in a direction orthogonal to the workpiece contact surface.

[0033] The active structure can be designed to guide the magnetic field component to the workpiece contact surface in such a way that the magnetic field component exits the workpiece contact surface for gripping the workpiece. The workpiece contact surface can be designed to make contact with the ferromagnetic workpiece.

[0034] As already mentioned, the workpiece contact surface can be flat or curved, especially convex, depending on the application.

[0035] The workpiece contact surface can form one end of the pole piece.

[0036] The workpiece contact surface can be defined by a chamfer or rounded portion of the pole piece. The chamfer or rounded portion of the pole piece can surround the workpiece contact surface all the way around. The chamfer or rounded portion can prevent a right-angled edge. The chamfer can be created by tapping the edge that defines the workpiece contact surface. The rounded portion can be created by rounding the edge that defines the workpiece contact surface.

[0037] The pole piece can have two centering holes for receiving cylindrical pins of the magnetic gripper for the purpose of aligning the pole piece relative to the housing of the magnetic gripper. In particular, the two centering holes can facilitate the alignment of the pole piece during attachment of the pole piece to the housing of the magnetic gripper.

[0038] A further aspect of the pole piece can be that a geometric shape of the pole piece forms the active structure. The active structure can be designed to guide the magnetic field component to the workpiece contact surface in such a way that the magnetic field component emerges from the workpiece contact surface in a focused manner for the purpose of increasing the holding force. In addition, the active structure can be designed to guide the magnetic field component to the workpiece contact surface, in particular to direct it, in such a way that the magnetic field component emerges from the workpiece contact surface with a smaller depth effect than with a pole piece without an active structure. As a result, the pole piece can enable a workpiece to be gripped by the magnetic gripper from a workpiece stack formed by individual, superimposed plate-shaped workpieces, without gripping an underlying workpiece.The continuous workpiece contact surface can prevent damage to the workpiece, for example, a coating on the workpiece. In a further development of the pole piece, the active structure causes a cross-sectional area of ​​the pole piece to increase from the workpiece contact surface in the direction of the fastening device. This advantageously allows the magnetic field component to be focused on the workpiece contact surface. In particular, the active structure can cause an amount of the cross-sectional area of ​​the pole piece to increase from the workpiece contact surface in the direction of the fastening device. This direction can be oriented orthogonally to the workpiece contact surface.

[0039] In a further development of the pole piece, the cross-sectional area of ​​the pole piece increases continuously or discontinuously. A continuous increase in the cross-sectional area can be understood as a continuous increase in the cross-sectional area. A discontinuous increase in the cross-sectional area can be understood as a sudden or step-like increase in the cross-sectional area.

[0040] In a further development of the pole piece, the knitted structure has a step-like design. Advantageously, a step-like knitted structure can be manufactured particularly easily. The step-like knitted structure can have a parallel course to the workpiece contact surface. The step-like knitted structure can be formed by a number, in particular 2, 3, 4 or 5, of steps. The steps can be formed by surfaces of the pole piece that are arranged parallel and offset from one another. The surfaces can be spaced apart at an equal distance from one another. In other words, the surfaces can be evenly spaced from one another. The surfaces of the pole piece forming the step-like knitted structure can be aligned parallel and offset from the workpiece contact surface.Due to the step-like active structure, the cross-sectional area of ​​the pole piece can increase discontinuously from the workpiece contact surface towards the fastening device.

[0041] In a further development of the pole piece, the active structure has a flat design. Due to the flat active structure, the cross-sectional area of ​​the pole piece can increase continuously from the workpiece contact surface towards the fastening device. The flat active structure can be formed by a flat surface of the pole piece. The flat active structure can extend as far as the workpiece contact surface. The angle between the flat active structure and the workpiece contact surface can be different from 90°, in particular greater than 90°. Preferably, the angle between the flat active structure and the workpiece contact surface can have an amount that is greater than 90° and less than 180°. The flat active structure can be unsuitable for contacting the workpiece. The flat active structure can be designed, in particular only, to increase the holding force of the magnetic gripper and / or to reduce the depth effect of the magnetic field component.

[0042] In a further development of the pole piece, the active structure has a number of recesses, for example, 2, 3, 4, 5, 6, or 8. Each recess has a longitudinal axis along which the recess extends. The recesses can be used to force the magnetic field component guided by the pole piece into a region of the pole piece that does not have the recess.

[0043] The number of recesses can be arranged in an edge region of the pole piece. The edge region can extend from the workpiece contact surface to one-half, preferably one-third or one-quarter, of the length of the pole piece. The length of the pole piece can be measured in a direction orthogonal to the workpiece contact surface. Each recess can penetrate the pole piece, in particular completely.

[0044] The recesses, or at least a number of them, can be filled with the non-ferromagnetic material of the pole piece. The non-ferromagnetic material can be, for example, a plastic, in particular an elastomer.

[0045] In a further development of the pole piece, the longitudinal axes of the recesses are aligned orthogonally or parallel to the workpiece contact surface.

[0046] In a further development of the pole piece, at least one of the plurality of recesses has a circular cross-section. Additionally or alternatively, at least one of the plurality of recesses has a rectangular, in particular square, cross-section. Advantageously, a recess with a circular cross-section and / or a recess with a rectangular cross-section can be manufactured particularly easily. Preferably, all recesses can have a circular cross-section or a rectangular cross-section.

[0047] At least one of the plurality of recesses can be formed as a hole, in particular a bore.

[0048] The diameters of the recesses can be the same or different.

[0049] In a further development of the pole shoe, each recess is designed as a hole, in particular a bore, which extends from a side of the pole shoe opposite the workpiece contact surface towards the workpiece contact surface.

[0050] Each hole can extend from the side of the pole piece opposite the workpiece contact surface to the workpiece contact surface in such a way that the hole does not reach the workpiece contact surface, in particular does not penetrate the workpiece contact surface. Alternatively, each hole can extend from the side of the pole piece opposite the workpiece contact surface to the workpiece contact surface in such a way that the hole reaches the workpiece contact surface, in particular penetrates the workpiece contact surface. Each hole can have a flat hole base.

[0051] A distance between the workpiece contact surface and the hole bottom may have an amount in a range of 1 mm to 5 mm, preferably 1 mm to 3 mm.

[0052] The side opposite the workpiece contact surface can form one end of the pole piece. The side opposite the workpiece contact surface can run parallel to the workpiece contact surface. The side opposite the workpiece contact surface can be formed by a flat surface of the pole piece. The side opposite the workpiece contact surface can be formed as a continuous surface. Each longitudinal axis of the holes can be aligned orthogonally to the workpiece contact surface.

[0053] In a further development of the pole shoe, each recess is designed as a hole, in particular a bore, which penetrates the pole shoe from one side of the pole shoe to a further side of the pole shoe opposite the side. Each hole, in particular a bore, can be aligned parallel to the workpiece contact surface. The side and the further side can run parallel to one another. The side and the further side can be flat. The side and the further side can each be a wide side of the pole shoe. Alternatively, the side and the further side can each be a narrow side of the pole shoe. The side and / or the further side can run orthogonally to the workpiece contact surface. The workpiece contact surface cannot be arranged on the side and / or the further side.

[0054] A distance between the workpiece contact surface and the hole, in particular bore, can have an amount in a range of 1 mm to 5 mm, preferably 1 mm to 3 mm.

[0055] In a further development of the pole shoe, a distance between the active structure and the workpiece contact surface is smaller than a distance between the active structure and the fastening device.

[0056] In a further development of the pole piece, the active structure has a sequence of elevations and / or recesses. The magnetic field component can be at least partially guided in the elevations. The recesses can be used to force the magnetic field component guided by the pole piece into an area of ​​the pole piece that does not have the recesses. In particular, the recesses can be used to force the magnetic field component guided by the pole piece into the elevations.

[0057] The recesses can be filled with the non-ferromagnetic material of the pole piece. The non-ferromagnetic material can be, for example, a plastic, particularly an elastomer.

[0058] The elevations and / or recesses can be evenly spaced from one another. The elevations and / or recesses can extend in a direction orthogonal to the workpiece contact surface. The elevations and / or recesses can be arranged on a side surface, in particular a broad side, of the pole piece. A recess can be arranged between two adjacent elevations. A elevation can be arranged between two adjacent recesses. The sequence can be formed by an alternating or alternating arrangement of recesses and elevations. The elevations and / or recesses can each have a rectangular cross-section. Each recess can be designed as a groove. The elevations and / or recesses can extend as far as the contact area.

[0059] In a further development of the pole piece, the recesses extend through the pole piece. This allows for a particularly efficient displacement of the magnetic field component into areas of the pole piece that do not have the recesses. Each recess can be designed as an elongated hole.

[0060] A magnetic gripper according to the invention for a handling device for gripping a ferromagnetic workpiece comprises a housing and a magnet arranged in the housing. The magnet can be transferred between a gripping state for gripping the ferromagnetic workpiece and a release state for releasing the ferromagnetic workpiece. Furthermore, the magnetic gripper comprises at least one first pole piece of the type described above and one second pole piece of the type described above. The first pole piece and the second pole piece are attached to the housing. The workpiece contact surface of the first pole piece and the workpiece contact surface of the second pole piece together form a holding surface of the magnetic gripper.Advantageous embodiments have exactly two of the aforementioned pole shoes; in particular, the two pole shoes can then be arranged substantially opposite one another on the housing, preferably on respective side surfaces of the housing of the magnetic gripper.

[0061] The handling device can be designed as a manipulator, for example in the form of a robot arm.

[0062] The housing can be formed in one piece or comprise a plurality of housing parts that, when assembled, form the housing. The housing can be non-magnetizable. The housing can be made of a non-ferromagnetic material, for example, aluminum. The magnet can be configured to generate the magnetic field. The magnet can be a permanent magnet and / or an electromagnet. The magnet can be supported by the housing. The housing can have an interior space in which the magnet is arranged.

[0063] The magnet may have a north pole and a south pole. The magnet's magnetic field may extend from the north pole to the south pole.

[0064] The magnet may be arranged in the housing such that in the gripping state the north pole is directed towards the first pole piece and the south pole is directed towards the second pole piece.

[0065] In the gripping state, a magnetic field component of the magnet's magnetic field can be guided to the holding surface via the pole pieces. In the release state, the magnetic field component of the magnet's magnetic field cannot be guided to the holding surface via the pole pieces.

[0066] The magnet can be transferred between the gripping state and the release state by a translational movement of the magnet. The translational movement can be a straight movement, in particular a vertical movement. For example, the magnet can be transferred between the gripping state and the release state by a linear displacement of the magnet, in particular in a direction parallel to the longitudinal axis of the magnetic gripper. Additionally or alternatively, the magnet can be transferred between the gripping state and the release state by a rotational movement of the magnet.

[0067] The magnet can be mounted in the housing so as to be linearly displaceable and / or rotatable, in particular along a longitudinal axis of the magnetic gripper.

[0068] The transition from the release state to the gripping state can be achieved by a linear displacement of the magnet within the housing toward the holding surface. The transition from the gripping state to the release state can be achieved by a linear displacement of the magnet within the housing away from the holding surface. The translational movement and / or the rotational movement of the magnet can be driven pneumatically, electrically, for example, by an electric motor or an electric linear drive, or mechanically, for example, by actuating a lever. In other words, the magnetic gripper can be actuated electrically, pneumatically, or mechanically.

[0069] The magnetic gripper can have an actuator for transferring the magnet between the gripping state and the release state. The actuator can be configured to drive the translational movement and / or the rotational movement of the magnet. The actuator can be an electric motor, a lever, and / or a pneumatic drive. In particular, the actuator can be configured as a pneumatic piston connected to the magnet. The housing can have a new pneumatic cylinder in which the pneumatic piston is arranged.

[0070] If the magnet can be transferred between the release state and the gripping state by a rotational movement, the magnet can have two separately formed magnet segments which are rotated against each other for transferring between the release state and the gripping state.

[0071] The magnetic gripper can have a plurality of magnets. If the magnetic gripper has a plurality of magnets, the magnetic gripper can have a plurality of first pole pieces and a plurality of second pole pieces. The number of magnets, the number of first pole pieces, and the number of second pole pieces can be the same. In particular, each magnet of the magnetic gripper can be assigned a first pole piece and a second pole piece. The same applies if the magnet has a higher segmentation, for example, greater than two.

[0072] The magnetic gripper can have a sensor for detecting the gripping state and / or the release state. The sensor can detect a position of the magnet in the housing. The magnetic gripper can have a control device that controls the actuator to transfer the magnet between the gripping state and the release state depending on the detected position of the magnet in the housing and / or on the detected gripping state or release state. The first pole piece and the second pole piece can be arranged opposite one another on the housing. The first pole piece and the second pole piece can be arranged on opposite sides of the housing. The first pole piece and the second pole piece can be releasably attached to the housing. In particular, the first pole piece and the second pole piece can be attached to the housing by means of a screw connection.

[0073] The first pole piece can be arranged on the housing such that, when the magnet is in the gripping state, the first pole piece acts as a north pole due to the magnetic field portion of the magnet guided by the first pole piece. The second pole piece can be arranged on the housing such that, when the magnet is in the gripping state, the second pole piece acts as a south pole due to the magnetic field portion of the magnet guided by the second pole piece.

[0074] The holding surface can be designed for contacting the ferromagnetic workpiece. The holding surface can be formed, in particular, only by the workpiece contact surface of the first pole piece and the workpiece contact surface of the second pole piece. Preferably, only the holding surface can be designed and / or provided for contacting the ferromagnetic workpiece.

[0075] When the magnet is in the gripping state and the workpiece is gripped by the magnetic gripper, a magnetic force can act on the workpiece via the magnetic field component, which pushes or presses the workpiece, in particular only, against the holding surface. The magnetic force can be greater than the weight of the workpiece.

[0076] The magnetic gripper can be controlled electrically or pneumatically.

[0077] In a further development of the magnetic gripper, the magnetic gripper has an adjustment device for adjusting a pole shoe distance between the first pole shoe and the second pole shoe and / or for adjusting a magnet distance between the magnet, particularly in the gripped state, and the two pole shoes. Adjusting the pole shoe distance using the adjustment device can be achieved, for example, by displacing at least one of the two pole shoes in a direction parallel to the holding surface.

[0078] The adjustment of the magnet distance using the adjustment device can be done, for example, by moving both pole pieces in a direction orthogonal to the holding surface.

[0079] The housing may include the adjustment device. The first and second pole pieces may be attached to the adjustment device.

[0080] Further advantages and advantageous embodiments of the invention can be gathered from the figures, their description, and the claims. All features disclosed in the figures, their description, and the claims can be essential to the invention both individually and in any combination. They show:

[0081] Fig. 1 is a schematic representation of a magnetic gripper in a release state,

[0082] Fig. 2 is a schematic representation of the magnetic gripper of Fig. 1 in a gripping state,

[0083] Fig. 3 is an oblique view of a first variant of a pole shoe of the magnetic gripper of Fig. 1,

[0084] Fig. 4 is another oblique view of the first variant of the pole piece of Fig. 3,

[0085] Fig. 5 a plan view of a workpiece contact surface of the first variant of the

[0086] Pole shoe of Fig. 3,

[0087] Fig. 6 is a sectional view of the first variant of the pole piece along a section line VI-VI according to Fig. 5,

[0088] Fig. 7 is an oblique view of a second variant of a pole shoe of the magnetic gripper of Fig. 1, Fig. 8 is an oblique view of a third variant of a pole shoe of the magnetic gripper of Fig. 1,

[0089] Fig. 9 is a side view of the third variant of the pole piece of Fig. 8,

[0090] Fig. 10 a sectional view of the third variant of the pole piece along a section line X-

[0091] X according to Fig. 9,

[0092] Fig. 11 is an oblique view of a fourth variant of a pole shoe of the magnetic gripper of Fig. 1,

[0093] Fig. 12 is a plan view of a side opposite the workpiece contact surface of the fourth variant of the pole piece of Fig. 11,

[0094] Fig. 13 is a sectional view of the fourth variant of the pole piece along a section line Xlll-Xlll according to Fig. 12,

[0095] Fig. 14 is an oblique view of a fifth variant of a pole shoe of the magnetic gripper of Fig. 1,

[0096] Fig. 15 is a plan view of the side opposite the workpiece contact surface of the fifth variant of the pole piece of Fig. 14,

[0097] Fig. 16 is a sectional view of the fifth variant of the pole piece along a section line XVI-XVI according to Fig. 15,

[0098] Fig. 17 is an oblique view of a sixth variant of a pole shoe of the magnetic gripper of Fig. 1,

[0099] Fig. 18 is another oblique view of the sixth variant of the pole piece of Fig. 17,

[0100] Fig. 19 is a side view of the sixth variant of the pole shoe of Fig. 17, Fig. 20 is an oblique view of a seventh variant of a pole shoe of the magnetic gripper of Fig. 1,

[0101] Fig. 21 is another oblique view of the seventh variant of the pole piece of Fig. 20,

[0102] Fig. 22 is a side view of the seventh variant of the pole piece of Fig. 20,

[0103] Fig. 23 is a side view of an eighth variant of a pole shoe of the magnetic gripper of Fig. 1,

[0104] Fig. 24 is a side view of a ninth variant of a pole shoe of the magnetic gripper of Fig. 1,

[0105] Fig. 25 is a side view of a tenth variant of a pole shoe of the magnetic gripper of Fig. 1,

[0106] Fig. 26 is an oblique view of an eleventh variant of a pole shoe of the magnetic gripper of Fig. 1,

[0107] Fig. 27 is a further oblique view of the eleventh variant of the pole piece of Fig. 26,

[0108] Fig. 28 is a front view of the eleventh variant of the pole piece of Fig. 26,

[0109] Fig. 29 is a sectional view of the eleventh variant of the pole piece along a section line XXIX-XXIX according to Fig. 28,

[0110] Fig. 30 is an oblique view of a twelfth variant of a pole shoe of the magnetic gripper of Fig. 1,

[0111] Fig. 31 is another oblique view of the twelfth variant of the pole piece of Fig. 30,

[0112] Fig. 32 is a front view of the twelfth variant of the pole piece of Fig. 30, Fig. 33 is a sectional view of the twelfth variant of the pole piece along a section line XXXIII-XXXIII according to Fig. 32,

[0113] Fig. 34 is an oblique view of a thirteenth variant of a pole shoe of the magnetic gripper of Fig. 1,

[0114] Fig. 35 is a further oblique view of the thirteenth variant of the pole piece of Fig. 34,

[0115] Fig. 36 is a front view of the thirteenth variant of the pole piece of Fig. 34,

[0116] Fig. 37 is a sectional view of the thirteenth variant of the pole piece along a section line XXXVI l-XXXVIl according to Fig. 36,

[0117] Fig. 38 is a schematic side view of the magnetic gripper of Fig. 2, and

[0118] Fig. 39 is a further schematic side view of the magnetic gripper of Fig. 38.

[0119] Fig. 1 schematically shows a magnetic gripper 10 for a handling device for gripping a ferromagnetic workpiece. The magnetic gripper 10 has a housing 12 that extends along a longitudinal axis 14 of the housing 12. The housing 12 is non-magnetizable. The housing 12 is made of aluminum.

[0120] The magnetic gripper 10 has a magnet 16 arranged in the housing 12. The magnet 16 is a permanent magnet. The magnet 16 has a north pole 18 and a south pole 20. A magnetic field 22 of the magnet 16 extends from the north pole 18 to the south pole 20. The magnetic field 22 runs along magnetic field lines 24. The magnet 16 is arranged in the housing 12 such that the north pole 18 and the south pole 20 are aligned orthogonally to the longitudinal axis 14.

[0121] The magnetic gripper 16 has a first pole piece 26 and a second pole piece 28. Each pole piece 26, 28 is made of a ferromagnetic material. In the illustrated embodiment, the two pole pieces 26, 28 are made of iron. Each pole piece 26, 28 is designed for magnetic coupling to the magnet 16. Each pole piece 26, 28 is designed to guide a magnetic field component of the magnetic field 22 to the ferromagnetic workpiece for gripping the ferromagnetic workpiece by the magnetic gripper 10.

[0122] Each pole piece 26, 28 is formed as a single piece. The two pole pieces 26, 28 are identical in construction. In an alternative embodiment (not shown), the two pole pieces may differ from each other.

[0123] The first pole piece 26 and the second pole piece 28 are arranged on opposite sides of the housing 12. The first pole piece 26 has a fastening device 30 for fastening the first pole piece 26 to the housing 12. The second pole piece 28 has a fastening device 32 for fastening the second pole piece 28 to the housing 12.

[0124] The first pole piece 26 and the second pole piece 28 are each releasably attached to the housing 12 by means of their fastening devices 30, 32. In particular, the two pole pieces 26, 28 are attached to the housing 12 by means of a screw connection. The screw connection enables the two pole pieces 26, 28 to be replaced.

[0125] The first pole piece 26 has an active structure 34 for directing the magnetic field, e.g., for increasing the holding force of the magnetic gripper and / or for reducing the depth effect of the magnetic field component. The second pole piece 28 has an active structure 36 for directing the magnetic field, e.g., for increasing the holding force of the magnetic gripper and / or for reducing the depth effect of the magnetic field component. In particular, the active structures 34, 36 are each designed to focus the magnetic field component guided by the pole pieces 26, 28. In other words, the active structures 34, 36 direct or focus the magnetic field component in a desired direction.

[0126] The first pole piece 26 has a workpiece contact surface 38 for contacting the workpiece. The workpiece contact surface 38 of the first pole piece 26 is formed as a continuous surface. The second pole piece 28 has a workpiece contact surface 40 for contacting the workpiece. The workpiece contact surface 40 of the second pole piece 28 is formed as a continuous surface.

[0127] The workpiece contact surfaces 38, 40 are each flat. The workpiece contact surface 38 of the first pole piece 26 forms one end of the first pole piece 26. The workpiece contact surface 40 of the second pole piece 28 forms one end of the second pole piece 28.

[0128] The two pole shoes 26, 28 are fastened to the housing 12 in such a way that the workpiece contact surfaces 38, 40 of the two pole shoes 26, 28 are aligned orthogonally to the longitudinal axis 14.

[0129] The workpiece contact surface 38 of the first pole piece 26 and the workpiece contact surface 40 of the second pole piece 28 together form a holding surface 42 of the magnetic gripper 10. The holding surface 42 can be formed solely by the workpiece contact surface 38 of the first pole piece 26 and the workpiece contact surface 40 of the second pole piece 28. The holding surface 42, in particular each workpiece contact surface 38, 40, is designed for contacting the ferromagnetic workpiece.

[0130] The active structures 34, 36 influence a course of the magnetic field component in the pole pieces 26, 28. The active structures 34, 36 are each designed to guide, in particular to focus, the magnetic field component from the magnet 16 to the workpiece contact surfaces 38, 40.

[0131] The magnet 16 can be transferred between a gripping state for gripping the ferromagnetic workpiece and a release state for releasing the ferromagnetic workpiece. The transfer between the gripping state and the release state is achieved by a translational movement of the magnet 16.

[0132] The translational movement is a linear movement. A direction of movement 44 of the linear movement can be aligned parallel to the longitudinal axis 14. The linear movement can be performed by a linear displacement of the magnet 16.

[0133] The linear displacement of the magnet 16 is achieved by means of a pneumatic drive 46 of the magnetic gripper 10. The pneumatic drive 46 can have a piston connected to the magnet 16. The housing 12 has a first opening 48 and a second opening 50. Gas can be supplied through the two openings 48, 50 in order to transfer the piston and thus the magnet 16 between the release state and the gripping state. By supplying gas via the first opening 48 into a housing section above the piston, the gas exerts pressure on an upper surface of the piston, thereby exerting a downward force on the piston and thus the magnet 16. In response, the piston and the magnet 16 move downward along the direction of movement 44 until the magnet 16 assumes the gripping state.

[0134] By supplying gas through the second opening 50 into a housing section below the piston, the gas exerts pressure on a lower surface of the piston, thereby exerting an upward force on the piston and thus on the magnet 16. In response, the piston and the magnet 16 move upward along the direction of movement 44 until the magnet 16 assumes the release state.

[0135] The release state is shown in Fig. 1. In the release state, the magnet 16 is arranged within the housing 12 such that no magnetic field component of the magnetic field 22 suitable for gripping the ferromagnetic workpiece is guided to the holding surface 42 by means of the pole pieces 26, 28. In the release state, the magnet 16 is not arranged between the two pole pieces 26, 28.

[0136] The gripping state is shown in Fig. 2. In the gripping state, the magnet 16 is arranged within the housing 12 such that a magnetic field component of the magnetic field 22, which is suitable for gripping the ferromagnetic workpiece, is guided to the holding surface 42 by means of the pole pieces 26, 28. In the gripping state, the magnet 16 is arranged between the two pole pieces 26, 28. In the gripping state, the first pole piece 26 acts as the south pole and the second pole piece 28 as the north pole. In an alternative embodiment, not shown, the first pole piece acts as the north pole and the second pole piece as the south pole.

[0137] Furthermore, Fig. 2 shows a stack of several workpieces 52. The several workpieces 52 are arranged one above the other, in particular stacked. This forms a stack of several workpieces 52.

[0138] Each workpiece 52 is made of iron. Each workpiece 52 is a sheet metal. The width and length of each workpiece 52 are more than five times the thickness of the workpiece 52. In the illustrated embodiment, the thickness of each workpiece 52 is 5 mm. Each workpiece 52 has a coating.

[0139] The magnetic gripper 10 is intended to grip the uppermost workpiece 52 from the stack of multiple workpieces 52 without gripping the remaining workpieces 52. For this purpose, the magnet 16 is transferred to the release state, and the magnetic gripper 10 is placed on the uppermost workpiece 52 such that the uppermost workpiece 52 rests against the holding surface 42. In other words, the workpiece 52 touches the workpiece contact surface 38 of the first pole piece 26 and the workpiece contact surface 40 of the second pole piece 28. The magnet 16 is then transferred to the gripping state, such that the magnetic field component of the magnetic field 22 guided by the two pole pieces 26, 28 is a component of the magnetic field 22 required for gripping the workpiece 52.

[0140] Through the active structures 34, 36, the magnetic field component of the magnetic field 22 is guided to the workpiece contact surfaces 38, 40 in such a way that a magnetic force acts on the stack of multiple workpieces 52. The magnetic force is only suitable for gripping the uppermost workpiece 52. In other words, the magnetic force acting on the uppermost workpiece 52 is greater than the weight of the uppermost workpiece 52. The magnetic force acting on the workpiece 52 located directly below the uppermost workpiece 52 is insufficient for gripping this workpiece 52. In other words, the magnetic force acting on the workpiece 52 located directly below the uppermost workpiece 52 is smaller than the weight of this workpiece 52.

[0141] The magnetic force presses the uppermost workpiece 52 against the holding surface 42, in particular against the two workpiece contact surfaces 38, 40.

[0142] By designing the workpiece contact surfaces 38, 40 as a continuous surface, the uppermost workpiece 52 is pressed against the workpiece contact surfaces 38, 40 by the magnetic force over a greater area than with a pole piece without a continuous workpiece contact surface. This can result in a more even pressure distribution on the uppermost workpiece 52, whereby the coating of the uppermost workpiece 52 is better protected from damage. Figs. 3 to 37 show various possible variants of the first and / or second pole piece 26, 28, wherein the same reference numerals are used for identical and functionally equivalent elements, so that reference can be made to the explanations for the respective elements and essentially only the existing differences between the various variants of the pole piece shown will be discussed.

[0143] For reasons of clarity, only the reference numerals of the first pole shoe 26 are used in these figures. The second pole shoe 28 can be constructed identically to the first pole shoe 26, which is why, in this case, the description of the first pole shoe 26 applies accordingly to the second pole shoe 28.

[0144] Fig. 3 to 6 show a first variant of the first pole shoe 26 of the magnetic gripper 10.

[0145] Fig. 3 shows the first pole shoe 26 looking towards a broad side 54 of the first pole shoe 26.

[0146] The workpiece contact surface 38 is orthogonal to the broad side 54. When the first pole piece 26 is attached to the housing 12, the broad side 54 faces away from the housing 12.

[0147] The fastening device 30 has two through holes 56. Each through hole 56 is suitable for receiving a fastening screw for establishing the screw connection for the purpose of fastening the first pole piece 26 to the housing 12. Each through hole 56 is designed as a countersunk bore.

[0148] The active structure 34 has a number of recesses 58. In the illustrated embodiment, the active structure is formed by six recesses 58. In a further embodiment not shown, the active structure can be formed by four, eight, or ten recesses. All recesses 58 can be of the same design.

[0149] Each recess 58 has a longitudinal axis 60 along which the recess 58 extends. The longitudinal axes 60 are aligned parallel and offset from one another. The longitudinal axes 60 run parallel to the workpiece contact surface 38. The longitudinal axes 60 can define a longitudinal axis plane that is aligned parallel and offset from the workpiece contact surface 38.

[0150] The recesses 58 are arranged to form a recess row. A direction 62 of the recess row runs parallel to the workpiece contact surface 38.

[0151] Each recess 58 has a rectangular, in particular square, cross-section.

[0152] Fig. 4 shows a further oblique view of the first pole piece 26 of Fig. 3, looking towards a further broad side 64 opposite the broad side 54.

[0153] When the first pole piece 26 is attached to the housing 12, the further broad side 64 faces the housing 12. When the first pole piece 26 is attached to the housing 12, the first pole piece 26 can bear against the housing 12 with a portion of the further broad side 64. In particular, fastening screws arranged in the through-holes 56 and with which the first pole piece 26 is attached to the housing 12 can press the portion of the further broad side 64 against the housing 12.

[0154] Each through-hole 56 has a counterbore 66 located on the wider side 64. In other words, the counterbore 66 faces the housing 12 when the first pole piece 26 is attached to the housing 12. The counterbore 66 is configured to receive an O-ring. The O-ring can serve to secure a fastening screw located in the through-hole 56.

[0155] The first pole piece 26 has two centering holes 68 for receiving cylindrical pins of the housing 12. During fastening of the first pole piece 26 to the housing 12, the cylindrical pins can be inserted into the two centering holes 68, thereby aligning the first pole piece 26 relative to the housing 12.

[0156] The first pole piece 26 has a curved surface section 70 arranged on the further broad side 64. The curved surface section 70 can extend to the workpiece contact surface 38. The curved surface section 70 can prevent an air gap between the housing 12 and the first pole piece 26, thereby optimally coupling the magnetic field component of the magnetic field of the magnet 16 into the first pole piece 26.

[0157] Figs. 3 and 4 show that the recesses 58 penetrate the first pole piece 26. In particular, the recesses 58 penetrate the first pole piece 26 from the broad side 54 to the further broad side 64.

[0158] The recesses 58 ensure that the magnetic field component guided by the first pole piece 26 and exiting the first pole piece 26 through the workpiece contact surface 38 is forced into an intermediate region 72 between the recesses 58. As a result, the magnetic field component is focused by means of the recesses 58 before exiting the workpiece contact surface 38, thereby increasing the holding force of the magnetic gripper 10 and reducing the depth effect of the magnetic field component.

[0159] Fig. 5 shows the first variant of the first pole piece 26 looking towards the workpiece contact surface 38. The workpiece contact surface 38 is formed as a single, continuous surface.

[0160] Fig. 6 shows a sectional view of the first variant of the first pole piece 26 along a section line VI-VI according to Fig. 5.

[0161] Each recess 58 has a height 74 and a width 76, with an amount of height 74 and an amount of width 76 being equal. Thus, each recess 58 has a square cross-section.

[0162] Two adjacent recesses 58 are spaced apart by a distance 78. The distance 78 can be equal to the width 76 or the height 74 of a recess 58. In the illustrated embodiment, the distance 78 is equal to the width 76 of a recess 58. All recesses 58 can be spaced apart by the same distance 78.

[0163] A distance 80 between the recesses 58 and the workpiece contact surface 38 is less than a distance 82 between the recesses 58 and the fastening device 30. The distance 80 between the recesses 58 and the workpiece contact surface 38 can have a value in a range of 1 mm to 5 mm. The distance 82 between the recesses 58 and the fastening device 30 can have a value in a range of 1 cm to 6 cm.

[0164] As a result, the recesses 58 are arranged in an edge region 84 of the first pole shoe 26, which extends from the workpiece contact surface 38 to one third of a length 86 of the first pole shoe 26.

[0165] Fig. 7 shows an oblique view of a second variant of the first pole piece 26. The first variant of the first pole piece 26 and the second variant of the first pole piece 26 differ in that the recesses 58 in the second variant of the first pole piece 26 are formed as bores. As a result, the recesses 58 have a circular cross-section. The recesses 58 have the same diameter 88. In an alternative embodiment, the recesses can have a different diameter from one another.

[0166] Fig. 8 to 10 show a third variant of the first pole shoe 26 of the magnetic gripper 10.

[0167] Fig. 8 shows that in the third variant of the first pole piece 26, the active structure 34 is formed by two recesses 58. Each recess 58 is designed as a bore. The recesses 58 penetrate the first pole piece 26 from a narrow side 90 of the first pole piece 26 to a further narrow side 92 of the first pole piece 26 opposite the narrow side 90.

[0168] The workpiece contact surface 38 runs orthogonally to the narrow side 90 and the further narrow side 92.

[0169] The narrow side 90 and the further narrow side 92 connect the broad side 54 to the further broad side 64. In other words, the narrow side 90 and the further narrow side 92 are arranged between the broad side 54 and the further broad side 64. The narrow side 90 and the further narrow side 92 each have a chamfer 94. The chamfer 94 is arranged on the broad side 54. Fig. 9 shows the first pole piece 26 with a view of the narrow side 90, and Fig. 10 shows a sectional view of the first pole piece 26 along a section line XX according to Fig. 9.

[0170] One of the two recesses 58 is interrupted by the curved surface section 70.

[0171] Fig. 11 to 13 show a fourth variant of the first pole shoe 26 of the magnetic gripper 10.

[0172] Fig. 11 shows that in the fourth variant of the first pole piece 26, the active structure 34 is formed by six recesses 58. Each recess 58 is designed as a hole.

[0173] The recesses 58 are arranged on a side 86 opposite the workpiece contact surface 38. Each recess 58 extends along its longitudinal axis 60. The longitudinal axes 60 of the recesses 58 are aligned orthogonally to the workpiece contact surface 38. The recesses 58 extend from the side 96 opposite the workpiece contact surface 38 toward the workpiece contact surface 38.

[0174] Fig. 12 shows a top view of the first pole piece 26, looking toward the side 96 opposite the workpiece contact surface 38. Each recess 58 has a circular cross-section. The diameters 88 of the recesses 58 differ from one another.

[0175] Fig. 13 shows a sectional view of the first pole piece 26 along a section line XI II-XII I according to Fig. 12. Each recess 58 has a flat hole base 98. Each recess 58 extends from the side 96 opposite the workpiece contact surface 38 toward the workpiece contact surface 38 in such a way that the recess 58 does not penetrate the workpiece contact surface 38. Each recess 58, in particular each hole base 98, is spaced from the workpiece contact surface 38 by a distance 80.

[0176] Figs. 14 to 16 show a fifth variant of the first pole piece 26 of the magnetic gripper 10. The active structure 34 is formed by 14 recesses 58. Each recess 58 is designed as a hole with a flat hole base 98. The diameters 88 of the recesses 58 are identical. In other words, the recesses 58 have the same diameter 88. Figs. 17 to 19 show a sixth variant of the first pole piece 26 of the magnetic gripper 10.

[0177] In the sixth variant of the first pole piece 26, the active structure 34 is designed in a stepped manner. The stepped active structure 34 is formed by a number of steps 100. In the embodiment of Figs. 17 to 19, the stepped active structure 34 is formed by two steps 100. Each step 100 extends from the narrow side 90 to the further narrow side 92.

[0178] Each step 100 extends parallel to the workpiece contact surface 38. Each step 100 is formed by a surface 102 of the first pole piece 26, which extends parallel and offset from the workpiece contact surface 38.

[0179] Due to the stepped active structure 34, the cross-sectional area of ​​the first pole piece 26 increases in a direction orthogonal to the workpiece contact surface 38, which is directed from the workpiece contact surface 38 toward the fastening device 30. The increase in the cross-sectional area occurs discontinuously, in particular abruptly. In other words, due to the stepped active structure 34, the cross-sectional area of ​​the first pole piece 26 decreases discontinuously in the direction toward the workpiece contact surface 38. By reducing the cross-sectional area, a focusing of the magnetic field component can be achieved before the magnetic field component exits through the workpiece contact surface 38.

[0180] Fig. 19 shows the sixth variant of the first pole piece 26, viewed toward the narrow side 90. The first pole piece 26 has a depth of 104. The two steps 100 each have a depth of 106. The depths 106 of the two steps 100 are equal. Each depth 106 of the steps 100 is one-third of the depth 104 of the first pole piece 26.

[0181] The workpiece contact surface 38 has a depth of 108. The depth 108 of the workpiece contact surface 38 is one third of the depth 104 of the first pole piece 26.

[0182] The two steps 100 each have a step height 110. The step height 110 of the two steps 100 is the same. In the illustrated embodiment, the step height 110 is 1.5 mm. In an alternative embodiment not shown, the step height can be in a range from 1 mm to 10 mm, in particular 1 mm to 5 mm.

[0183] Fig. 20 to 22 show a seventh variant of the first pole shoe 26 of the magnetic gripper 10.

[0184] In the seventh variant of the first pole piece 26, the active structure 34 is flat. The flat active structure 34 is formed by a flat surface 112. The flat surface 112 has an oblique profile with respect to the workpiece contact surface 38. The flat surface 112 meets the workpiece contact surface 38, forming an edge 114 of the first pole piece 26. The edge 114 extends from the narrow side 90 to the further narrow side 92. The edge 114 is aligned parallel to the wide side 54.

[0185] The edge 114 can be formed as a blunt edge. A blunt edge can be understood as an edge formed by the intersection of the workpiece contact surface 38 and the flat surface 112, wherein an angle 116 between the workpiece contact surface 38 and the flat surface 112 is greater than 90° and less than 180°.

[0186] The flat surface 112 is arranged such that the cross-sectional area of ​​the first pole piece 26 increases steadily, in particular continuously, in a direction orthogonal to the workpiece contact surface 38, which is directed from the workpiece contact surface 38 toward the fastening device 30. In other words, the flat surface 112 causes the cross-sectional area of ​​the first pole piece 26 to decrease steadily in the direction toward the workpiece contact surface 38. By reducing the cross-sectional area, a focusing of the magnetic field component can be achieved before the magnetic field component exits through the workpiece contact surface 38.

[0187] Fig. 22 shows the seventh variant of the first pole piece 26, viewed toward the narrow side 90. The depth 108 of the workpiece contact surface 38 is 3.5 mm. The angle 116 between the workpiece contact surface 38 and the flat surface 112 is 150°.

[0188] Fig. 23 shows an eighth variant of the pole piece 26, viewed toward the narrow side 90. The depth 108 of the workpiece contact surface 38 is 3.5 mm. The angle 116 between the workpiece contact surface 38 and the flat surface 112 is 140°. Fig. 24 shows a ninth variant of the pole piece 26, viewed toward the narrow side 90. The depth 108 of the workpiece contact surface 38 is 1.5 mm. The angle 116 between the workpiece contact surface 38 and the flat surface 112 is 160°.

[0189] Fig. 25 shows a tenth variant of the pole piece 26, viewed from the narrow side 90. The depth 108 of the workpiece contact surface 38 is 1.5 mm. The angle 116 between the workpiece contact surface 38 and the flat surface 112 is 150°.

[0190] The depth of the workpiece contact surface 38 can be in a range from 1 mm to 4 mm, in particular 1.5 mm to 3.5 mm. The angle 116 between the workpiece contact surface 38 and the flat surface 112 can be in a range from 130° to 170°, in particular 140° to 160°.

[0191] Fig. 26 to 29 show an eleventh variant of the first pole shoe 26 of the magnetic gripper 10.

[0192] In the illustrated example, the active structure 34 is formed by a sequence of elevations 118 and recesses 120. The sequence is formed by arranging a recess 120 between each two adjacent elevations 118. A generally advantageous implementation of the active structure 34 can be web-like elevations, for which the elevations 118 are exemplary implementations.

[0193] The recesses 120 are provided to force the magnetic field component into the elevations 118 for guidance. The elevations 118 are designed to guide the magnetic field component to the workpiece contact surface 38.

[0194] The elevations 118 and the recesses 120 are arranged between the fastening device 30 and the workpiece contact surface 38. The elevations 118 and the recesses 120 are arranged, in particular, only on the broad side 54. The course of each elevation 118 and each recess 120 is orthogonal to the workpiece contact surface 38.

[0195] Each protrusion 118 has a longitudinal axis 122 along which the protrusion 118 extends. The longitudinal axes 122 of the protrusions 118 are aligned parallel and offset from one another. The longitudinal axes 122 of the protrusions 118 are orthogonal to the workpiece contact surface 38. The longitudinal axes 122 of the protrusions 118 can define a longitudinal axis plane that is aligned orthogonal to the workpiece contact surface 38.

[0196] A length 124 of the elevations 118 can have a value that lies in a range of 50% to 80%, in particular 60% to 75%, of the length 86 of the first pole piece 26. In the illustrated embodiment, the length 124 of the elevations 118 is two-thirds of the length of the first pole piece 26.

[0197] The recesses 120 are spaced apart from the workpiece contact surface 38 by a distance 126. The distance 126 can be in a range of 1 mm to 3 mm.

[0198] Fig. 29 shows a sectional view of the eleventh variant of the first pole piece 26 along a section line XXIX-XXIX according to Fig. 28.

[0199] Each recess 120 has a height 128 and a width 130, with an amount of the height 128 and an amount of the width 130 being equal. Thus, each recess 120 has a square cross-section.

[0200] Two adjacent recesses 120 are spaced apart by a distance 132. The distance 132 may be equal to the width of a protrusion 118. All recesses 120 may be spaced apart by the same distance 132.

[0201] The distance 132 between two adjacent recesses 120 may be smaller than the height 128 of the recesses 120.

[0202] Figs. 27 and 28 show that the first pole piece 26 has a chamfer 134. The workpiece contact surface 38 is delimited by the chamfer 134. The chamfer 134 circumferentially surrounds the workpiece contact surface 38. The chamfer 134 prevents the workpiece contact surface 38 from being delimited by an edge, in particular a sharp edge. Figs. 30 to 33 show a twelfth variant of the first pole piece 26 of the magnetic gripper 10. In detail, Figs. 30 and 31 each show an oblique view, Fig. 32 a front view, and Fig. 33 a sectional view along a section line XXXI II-XXXI II according to Fig. 32.

[0203] The twelfth variant of the first pole piece 26 and the eleventh variant of the first pole piece 20 differ, for example, in that the recesses 120 in the twelfth variant of the first pole piece 26 penetrate the first pole piece 26. The recesses 120 penetrate the first pole piece 26 completely. In other words, the recesses 120 penetrate the first pole piece 26 from the broad side 54 to the further broad side 64.

[0204] Furthermore, the twelfth variant of the first pole shoe 26 has no chamfer 134. In a further embodiment not shown, the first pole shoe can be designed according to the twelfth variant of the first pole shoe and have the chamfer.

[0205] Fig. 34 to 37 show a thirteenth variant of the first pole piece 26 of the magnetic gripper 10. In detail, Fig. 34 and 35 each show an oblique view, Fig. 36 a front view and Fig. 37 a sectional view along a section line XXXVI l-XXXVIl according to Fig. 36.

[0206] The thirteenth variant of the first pole piece 26 and the twelfth variant of the first pole piece 20 differ, for example, in that each recess 120 in the thirteenth variant of the first pole piece 26 is designed as an elongated hole. All elongated holes are designed identically.

[0207] Fig. 36 shows that each elongated hole has two opposite narrow sides 136 and two opposite long sides 138. Each narrow side 136 is formed by a semicircle whose diameter is equal to the width of the elongated hole. The long sides 138 of each elongated hole run parallel to each other.

[0208] The recesses 120 are arranged relative to one another such that the longitudinal sides 138 are aligned parallel to one another. The longitudinal sides 138 extend orthogonally to the workpiece contact surface 38.

[0209] Furthermore, the thirteenth variant of the first pole piece 26 has the chamfer 134. Figures 38 and 39 each show a schematic view of the magnetic gripper 10 in the gripping state. The magnet 16 is shown in dashed lines in Figures 38 and 39.

[0210] The housing 12 is constructed in several parts. The housing 12 has a mechanical connection 140 for attaching the magnetic gripper 10 to the handling device. The handling device can be, for example, a robot arm. The mechanical connection 140 is formed by two threaded holes for establishing a screw connection between the magnetic gripper 10 and the handling device.

[0211] The mechanical connection 140 is arranged in an end region of the magnetic gripper 10. The end region is arranged at an end of the magnetic gripper 10 opposite the two pole pieces 26, 28.

[0212] The first pole shoe 26 and the second pole shoe 28 are each designed according to the tenth variant of the first pole shoe 26 shown in Fig. 25.

[0213] The magnetic gripper 10, in particular the housing 12, has an adjustment device 142 for adjusting a pole shoe distance 144 between the first pole shoe 26 and the second pole shoe 28 and for adjusting a magnet distance 146 between the magnet 16 in the gripping state and the two pole shoes 26, 28. By adjusting the pole shoe distance 144 and the magnet distance 146, a size of the magnetic field component can be adjusted, which is guided to the workpiece contact surface 38 by means of the two pole shoes 26, 28 when the magnet 16 is in the gripping state.

[0214] The adjustment device 142 can have a locking element for locking the adjustment device 142. To change the pole shoe spacing 144 and / or the magnet spacing 146, the locking element can be released and then the pole shoe spacing 144 and / or the magnet spacing 146 can be adjusted by moving the first pole shoe 26 and the second pole shoe 28. The locking element can then be locked to prevent unwanted displacement of the first pole shoe 26 and the second pole shoe 28. The magnet spacing 146 can be adjusted by moving the two pole shoes 26, 28 in a direction that runs parallel to the longitudinal axis 14 of the housing 12. The pole shoe spacing 144 can be adjusted by moving the two pole shoes 26, 28 in a direction that runs parallel to the workpiece contact surface 38.

[0215] For example, the pole shoe distance 144 can be adjusted by pulling the two pole shoes 26, 28 apart or pressing them together.

Claims

Patent claims 1. Pole shoe (26, 28) for a magnetic gripper (10) for guiding a magnetic field component of the magnetic gripper (10) to a ferromagnetic workpiece (52) for gripping the ferromagnetic workpiece (52), comprising: a fastening device (30, 32) for fastening the pole shoe (26, 28) to a housing (12) of the magnetic gripper (10), an active structure (34, 36) for magnetic field steering, and a workpiece contact surface (38, 40) which is designed to bear against the ferromagnetic workpiece (52) when gripping the ferromagnetic workpiece (52), wherein the workpiece contact surface (38, 40) is designed as a continuous surface.

2. Pole shoe (26, 28) according to claim 1, wherein the active structure (34, 36) is designed such that a cross-sectional area of ​​the pole shoe (26, 28) increases starting from the workpiece contact surface (38, 40) in the direction of the fastening device (30, 32).

3. Pole shoe (26, 28) according to claim 2, wherein the cross-sectional area increases continuously or discontinuously.

4. Pole shoe (26, 28) according to claim 2 or 3, wherein the active structure (34, 36) has a step-like design.

5. Pole shoe (26, 28) according to claim 2 or 3, wherein the active structure (34, 36) has a planar configuration.

6. Pole piece (26, 28) according to one of the preceding claims, wherein the active structure (34, 36) has a number of recesses (58), each recess (58) having a longitudinal axis (60) along which the recess (58) extends.

7. Pole shoe (26, 28) according to claim 6, wherein the longitudinal axes (60) of the recesses (58) are aligned orthogonally or parallel to the workpiece contact surface (38, 40).

8. Pole shoe (26, 28) according to claim 6 or 7, wherein at least one recess (58) has a circular cross-section, and / or wherein at least one recess (58) has a rectangular cross-section.

9. Pole piece (26, 28) according to one of the preceding claims 6 to 8, wherein each recess (58) is formed as a hole extending from a side of the pole piece opposite the workpiece contact surface (38, 40) towards the workpiece contact surface (38, 40).

10. Pole shoe (26, 28) according to one of the preceding claims 6 to 8, wherein each recess (58) is formed as a hole which penetrates the pole shoe (26, 28) from one side of the pole shoe (26, 28) to a further side of the pole shoe (26, 28) opposite the side.

11. Pole shoe (26, 28) according to one of the preceding claims, wherein a distance between the active structure (34, 36) and the workpiece contact surface (38, 40) is less than a distance between the active structure (34, 36) and the fastening device (30, 32).

12. Pole shoe (26, 28) according to one of the preceding claims, wherein the active structure (34, 36) has a sequence of elevations (118) and / or recesses (120).

13. Pole shoe (26, 28) according to one of the preceding claims 12, wherein the recesses (120) penetrate the pole shoe (26, 28).

14. Magnetic gripper (10) for a handling device for gripping a ferromagnetic workpiece (52), comprising: a housing (12), a magnet (16) which is arranged in the housing (12) and which can be transferred between a gripping state for gripping the ferromagnetic workpiece (52) and a release state for releasing the ferromagnetic workpiece (52), - a first pole shoe (26) according to one of the preceding claims, and a second pole shoe (28) according to one of the preceding claims, wherein the first pole shoe (26) and the second pole shoe (28) are fastened to the housing (12), wherein the workpiece contact surface (38) of the first pole shoe (26) and the workpiece contact surface (40) of the second pole shoe (28) together form a holding surface (42) of the magnetic gripper (10).

15. Magnetic gripper (10) according to claim 14, wherein the magnetic gripper (10) has an adjustment device (142) for adjusting a pole shoe distance (144) between the first pole shoe (26) and the second pole shoe (28) and / or for adjusting a magnet distance (146) between the magnet (16) and the two pole shoes (26, 28).

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