Gripping device

Abstract

To provide a gripping device capable of stably and reliably gripping an object with a simple configuration.SOLUTION: A gripping device 10 grips an object 14 by first and second gripping members 12, 13 opposed to each other with a gap therebetween. The gap between the first and second gripping members 12, 13 can be adjusted by position adjustment means 16. At least one or both of the first and second gripping members 12, 13 comprise: a plate-shaped base part 17; and a plurality of pressing parts 18 that are attached and fixed in an upright state to the base part 17 and are capable of contacting the object 14. The respective pressing parts 18 are arranged adjacently in vertical and horizontal directions on the base part 17, and are individually elastically deformable when the object 14 is gripped by the first and second gripping members 12, 13.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gripping device for gripping an object. [Background technology]

[0002] For example, in logistics and industry, automation of tasks is progressing. In automating such work, a gripping device is used that grips an object by sandwiching it between first and second gripping members that face each other with a gap between them.

[0003] For example, a gripping device 80 shown in FIG. 8(a) is a device that grips an object 83 by restraining (force restraining) it with the clamping force of first and second gripping members 81 and 82 (see, for example, Patent Document 1). However, because the contact surfaces of the first and second gripping members 81, 82 with the object 83 are flat, if the outer surface of the object is curved, for example, the first and second gripping members 81, 82 will not conform to the shape of the outer surface of the object when they come into contact with the object, but will make contact in a line or at a point. For this reason, depending on the shape and weight of the object, it may not be possible to stably and reliably grip the object. Furthermore, if the clamping force between first gripping member 81 and second gripping member 82 is increased in order to stably and reliably grip the object, the object may be damaged depending on the material of the object.

[0004] On the other hand, the gripping device 90 shown in Figure 8(b) is a device that grips an object 93 by constraining (force constraint + shape constraint) using the clamping force and shape deformation of first and second gripping members 91 and 92 (see, for example, Patent Document 2). As a result, even if the outer surface of the object is curved, the contact surfaces of the first and second gripping members 91, 92 with the object deform to a shape that conforms to the outer surface of the object, allowing the object to be gripped stably and reliably. Furthermore, in order to stably and reliably grip the object, it is not necessary to excessively increase the clamping force between first gripping member 91 and second gripping member 92, and damage to the object can be suppressed and even prevented. In FIGS. 8(a) and 8(b), reference numeral 100 denotes a robot arm to which the gripping devices 80 and 90 are attached. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-28920 A [Patent Document 2] Patent No. 6883908 Summary of the Invention [Problem to be solved by the invention]

[0006] However, even if the first and second gripping members 91, 92 of the gripping device 90 have both the force constraint and shape constraint functions, there are cases where their ability to follow the shape of an object when they come into contact with it is insufficient. For example, as shown in Figure 8(b), when multiple ribs are provided on the outer periphery of the storage container (object 93), the shape of the object 93 changes significantly, and the first and second gripping members 91, 92 are pulled by the surrounding shape, making it difficult for them to penetrate between adjacent ribs. Furthermore, as shown in Figure 9(a), when the object 94 is rod-shaped and contacts the first gripping member 91 from a direction perpendicular to the object 94, the first gripping member 91 will attempt to deform to conform to the shape of the object 94. However, as shown in Figure 9(b), when the object 94 contacts the first gripping member 91 from an oblique direction, it is difficult for the first gripping member 91 to conform to the shape of the object (the same applies to the second gripping member 92). Therefore, even if a gripping device 90 in which the first and second gripping members 91, 92 have both the force constraint and shape constraint functions is used, there is a risk that the object may not be gripped stably and reliably.

[0007] An object of the present invention is to provide a gripping device that has a simple configuration and is capable of stably and reliably gripping an object. [Means for solving the problem]

[0008] The present invention is as follows. [1] A gripping device that grips an object using first and second gripping members that face each other with a gap between them, The distance between the first and second gripping members is adjustable by a position adjusting means, A gripping device characterized in that either one or both of the first and second gripping members comprises a planar base portion and a plurality of pressing portions attached and fixed in an upright state to the base portion and capable of contacting the object, the pressing portions being arranged adjacent to each other vertically and horizontally on the base portion and being individually elastically deformable when the object is gripped by the first and second gripping members.

[0009] [2] The gripping device according to [1], wherein the tip of the pressing part is hemispherical in shape.

[0010] [3] The gripping device according to [1] or [2], wherein the pressing portion has a lattice structure.

[0011] [4] The gripping device according to any one of [1] to [3], wherein the plurality of pressing parts are configured with different hardnesses.

[0012] [5] The gripping device according to any one of [1] to [4], wherein the pressing portion is attachable to and detachable from the base portion.

[0013] [6] The gripping device according to any one of [1] to [5], wherein the pressing part is made of a single material.

[0014] [7] A gripping device according to any one of [1] to [6], characterized in that it has multiple pairs of the first and second gripping members, and each of the multiple pairs of first and second gripping members is arranged so that it can grip the object from around the center.

[0015] [8] The gripping device according to any one of [1] to [7], wherein the base portion is disposed at an angle such that the axis of each of the pressing portions faces obliquely upward. [Effects of the Invention]

[0016] According to the gripping device of the present invention, an object can be gripped stably and reliably with a simple configuration. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is an explanatory diagram showing a state in which a gripping device according to an embodiment of the present invention is used; [Figure 2] 1(a) is an explanatory diagram showing the arrangement of the pressing portion when the first gripping member of the gripping device is viewed from the front, and FIG. 1(b) is an explanatory diagram showing another arrangement of the pressing portion. [Figure 3] 1(a) to 1(c) are a perspective view, a plan view, and a side view, respectively, of the pressing portions of the first and second gripping members of the gripping device. [Figure 4] 10(a) and 10(b) are explanatory views showing a state when a rod-shaped object comes into contact with a first gripping member of the gripping device. [Figure 5] FIG. 10(a) is an explanatory diagram of a first gripping member of a gripping device according to a first modification, and FIG. 10(b) is an explanatory diagram showing the first gripping member in use. [Figure 6] 10 is an explanatory diagram of a first gripping member of a gripping device according to Modification 2. FIG. [Figure 7] 10 is an explanatory diagram of a first gripping member of a gripping device according to a third modification. FIG. [Figure 8] 10(a) and 10(b) are explanatory views showing the state in which gripping devices according to Conventional Examples 1 and 2 are used. [Figure 9] 10(a) and 10(b) are explanatory views showing a state when a rod-shaped object comes into contact with the first gripping member of the gripping device according to Conventional Example 2. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] Next, embodiments of the present invention will be described with reference to the accompanying drawings to facilitate understanding of the present invention. A gripping device 10 according to one embodiment of the present invention shown in Fig. 1 is used as an end effector (i.e., a gripper) of a robot arm 11 that is an industrial robot or a collaborative robot, and is a device that can stably and reliably grip (clamp) objects 14 of various shapes, masses, and sizes using first and second gripping members 12, 13 that face each other with a gap between them. Note that Fig. 1 shows a storage container (small container) as the object 14 to be gripped, but examples include various types of equipment, parts, food, and bags or boxes (containers) that contain these, and the shapes, masses, and sizes thereof vary (for example, rod-shaped, plate-shaped, spherical, rectangular, or cubic).

[0019] The gripping device 10 has an attachment means 15 for attaching the gripping device 10 to a robot arm 11, and first and second gripping members 12, 13 attached to the attachment means 15 via a position adjustment means 16. A detailed explanation is provided below.

[0020] The attachment means 15 is for attaching and fixing the gripping device 10 to the tip of the robot arm 11 in a detachable (removable) manner. For example, it is in the shape of a plate, and the tip of the robot arm 11 is detachably attached to the center of the upper side (one side) of the attachment means, and the position adjustment means 16 is attached to the lower side (other side) of the attachment means. This attachment means is not limited to the above configuration as long as it can detachably attach the gripping device to the tip of the robot arm and can attach the position adjustment means. It is also possible to fix the gripping device to the tip of the robot arm 11 without using the attachment means 15, so that it cannot be removed.

[0021] The position adjustment means 16 moves both the first and second gripping members 12 and 13 along the mounting means to narrow or widen the gap between the opposing first and second gripping members 12 and 13. This gap adjustment can be achieved using a conventionally known configuration, for example, including a linear guide, a ball screw arranged along the longitudinal direction of the linear guide, and a motor that drives the ball screw to rotate in both directions around its axis. In this case, both the first and second gripping members can be moved simultaneously (see, for example, Japanese Patent No. 6883908). Alternatively, a driving means such as a motor can be used instead of the ball screw to move the first and second gripping members simultaneously or individually.

[0022] The first and second gripping members 12, 13 have a plate-shaped base portion 17 and a plurality of pressing portions 18 attached and fixed to the base portion 17 in an upright state, and are attached to the position adjustment means 16 so that the base portion 17 is in an upright state relative to the attachment means 15. The base portion 17 is a wide plate made of a hard material (e.g., metal or plastic), and is attached and fixed to the position adjustment means 16 so that the wide surfaces of the base portion 17 face each other in the pair of first and second gripping members 12, 13 (so that the width direction of the base portion 17 is perpendicular to the adjustment direction of the spacing between the opposing first and second gripping members 12, 13).

[0023] 1, the opposing base portions 17 of the first and second gripping members 12, 13 are attached and fixed to the position adjustment means 16 so that they are parallel, but for example, they can also be attached and fixed to the position adjustment means 16 so that the axis of each pressing portion 18 faces diagonally upward, that is, so that the base portions 17 are arranged at an incline. In this case, the distance between the opposing base portions 17 of the first and second gripping members 12, 13 gradually increases upward. This allows, for example, when lifting an object gripped by the first and second gripping members, to stably grip the object even if the pressing portions 18 bend downward due to the weight of the object. The first and second gripping members 12, 13 have their base portions 17 fixed to the position adjustment means 16, but may also be configured to be detachable from the position adjustment means 16 (replaceable).

[0024] The multiple pressing portions 18 are capable of coming into contact with the object 14, are attached and fixed in an upright state to the base portion 17, and are arranged adjacently in the vertical and horizontal directions on the base portion 17. Here, the upright state means a state in which the pressing portions 18 are attached and fixed so as to protrude toward the object 14 to be grasped, specifically, so that their axes are at 90 degrees relative to the base portion 17, but they may also be attached and fixed at an angle such that their axes are at an angle between 60 degrees and 90 degrees relative to the base portion. Although the axes of all the pressing portions 18 are directed in the same direction, some (for example, for each of the multiple divided regions) or all of them may be directed in different directions.

[0025] The number of pressing portions 18 provided on the first gripping member 12 (one gripping member) is, for example, about 5 to 30, preferably about 5 to 20, and they can be arranged in multiple sets (rows) horizontally, with multiple pressing portions lined up vertically as one set (the same applies to the second gripping member 13). Specifically, as shown in Figures 1 and 2(a), three pressing portions are arranged in a vertical line to form one set, and five sets (rows) are arranged in a horizontal line. Alternatively, as shown in Figure 2(b), a plurality of pressing portions 18 can be arranged in five sets (rows) in a horizontal line, with two pressing portions arranged in a vertical line to form one set. The first and second gripping members 12 and 13 have the same number of pressing portions 18, but the pair of gripping members may have different numbers.

[0026] The multiple pressing parts 18 are arranged at the intersections of the grid so that the spacing between adjacent pressing parts 18 in the vertical and horizontal directions is equal, but they can also be arranged in a honeycomb shape so that the spacing between adjacent pressing parts is minimized. Here, the interval (minimum interval) s between adjacent pressing portions 18 in the vertical or horizontal direction may be such that a slight gap is provided, and preferably such that deformation of adjacent pressing portions 18 is not hindered when the pressing portions come into contact with an object. For example, although it depends on the size of the pressing portions and the degree of deformation, the interval s is preferably about 1 mm to 10 mm, more preferably about 2 mm to 8 mm, and even more preferably about 3 mm to 8 mm.

[0027] The pressing portion 18 is elastically deformable when gripping the object 14, and is preferably cylindrical in shape with a dome-shaped tip that is hemispherical, as shown in Figures 1 to 3. The diameter (width) d of the pressing portion 18 is, for example, about 10 mm to 50 mm, preferably about 15 mm to 40 mm, more preferably about 20 mm to 40 mm, and even more preferably about 25 mm to 35 mm. The height h of the pressing portion 18 is, for example, about 10 mm to 100 mm, preferably about 15 mm to 80 mm, more preferably about 20 mm to 60 mm, and even more preferably about 35 mm to 50 mm. The multiple pressing portions 18 have the same shape and size, but some of the pressing portions (for example, for each of the multiple divided regions) may have different shapes and / or sizes.

[0028] The pressing portion 18 is a flexible finger (soft finger) made of a wear-resistant material such as rubber or resin, and is elastically deformable. For example, it is preferable to determine the structure and material of the pressing portion 18 so that when the pressing force on the pressing portion is 10 N, the amount of compression in the axial direction is about 2.5 to 5 mm, and the load capacity is about 1.5 to 3.5 N. Specifically, the pressing portion 18 can be made of a single material (abrasion-resistant material) and its internal structure can be loose, such as a lattice structure, honeycomb structure, sponge structure, etc., and it is particularly preferable to use the lattice structure shown in Figures 3(a) to 3(c). This lattice structure is a special structure, and can be manufactured using a 3D printer, for example.

[0029] The rubber or resin wear-resistant material constituting the pressing portion 18 is a material that can slow down the progression of wear due to contact with the object to be gripped, and is preferably, for example, urethane rubber (ether-based or ester-based, etc.) with a Shore hardness (Shore hardness (HS hardness): JIS K 6253, etc.) of 60 to 90, preferably with a lower limit of 65, further 70, and an upper limit of 85, further 80, but the following materials can also be used. The multiple pressing portions 18 are made of the same material, but some of the pressing portions (for example, each of the multiple divided regions) may be made of different materials.

[0030] Examples of rubber include nitrile rubber (NBR), chloroprene rubber (CR), fluororubber, natural rubber (NR), synthetic natural rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), butyl rubber (IIR), ethylene-propylene rubber (EPR), acrylic rubber (ACM), chlorosulfonated polyethylene rubber (CSM), ethylene-vinyl acetate rubber (EVA), and epichlorohydrin rubber (CO, ECO). Examples of resins include soft resins such as olefin resins (polypropylene resin, polyethylene resin, etc.), urethane resins, soft vinyl chloride resins, thermoplastic elastomers (olefin thermoplastic elastomers, styrene thermoplastic elastomers, modified styrene thermoplastic elastomers, urethane thermoplastic elastomers (TPU), hydrogenated styrene butadiene rubber (HSBR), etc.), and mixtures thereof. An example of the mixture is a copolymer resin made of polyethylene resin and ethylene vinyl acetate resin (EVA resin).

[0031] By configuring it in this way, even if multiple ribs are provided on the outer periphery, such as in the case of a storage container, which is the object 14 shown in Figure 1, the multiple pressing parts 18 can respond individually and are not affected by the surrounding shape, making it easier to penetrate between adjacent ribs. Furthermore, even in the case of the rod-shaped object 14a shown in FIGS. 4(a) and 4(b), the pressing portion 18 can easily follow the shape of the object 14a regardless of the contact direction of the object 14a with the pressing portion 18. Therefore, by using the gripping device 90 having the first and second gripping members 12, 13 provided with the multiple pressing portions 18, for example, the objects 14, 14a can be gripped stably and reliably.

[0032] The gripping device may also be configured to include a first gripping member 12a as shown in FIG. 5(a) (the same applies to the second gripping member). It is preferable that the plurality of pressing portions 18 and the pressing portion 18a provided on the first gripping member 12a (one gripping member) are configured to have different hardnesses. The pressing portion 18a is configured to be harder than the pressing portion 18, and is less susceptible to elastic deformation. This can be adjusted by changing the internal structure and material as described above. 5(a), pressing portion 18a, which is harder than pressing portion 18, is located at the lowest position (lower region), but may be located at the upper position (upper region) or the middle position (middle region) depending on the object, and pressing portions 18 and 18a may be alternately arranged in one or more of the vertical, horizontal, and diagonal directions. In this way, by changing the hardness of the pressing portion depending on the arrangement location, it is possible to further improve the tracking performance.

[0033] Furthermore, the pressing portion 18 attached to the base portion 17 can be made detachable from the base portion 17 . 5(a) and (b), the pressing portion 18a is configured to be harder than the pressing portion 18, and since the pressing portion 18 is used in a location that is subject to large deformation, it is prone to damage. For this reason, by making the pressing portion 18 detachable from the base portion 17, it becomes possible to replace only the damaged portion, as shown in FIG. 6, which reduces costs compared to replacing the entire gripping member. The pressing portion 18a can also be attached to and detached from the base portion 17.

[0034] Here, the following configurations are available for making the pressing portion 18 attachable to and detachable from the base portion 17. A male threaded portion is attached and fixed to the base portion, and a female threaded portion that screws into this is provided at the base end of the pressing portion. Furthermore, the pressing portion can be attached to and detached from the base portion with a single touch.

[0035] Furthermore, by making the plurality of pressing portions 18, 18a attachable to and detachable from the base portion 17, it becomes possible to change (recombine) the arrangement of the pressing portions 18, 18a depending on the object. For example, in FIG. 7, the pressing portion 18a arranged at the bottom can be replaced with the pressing portion 18 arranged at the middle position. This configuration makes it possible to use one gripping member to grip multiple types of objects, making it easy to use.

[0036] The gripping device may also have multiple pairs of first and second gripping members. For example, if the object is rectangular or square in plan view, it is preferable to arrange two pairs of first and second gripping members so that they surround the four sides of the object and can grip the object from the periphery with the object at the center. Specifically, if the object is rectangular in plan view, it is preferable to arrange the first and second gripping members so that the spacing adjustment directions of one pair of first and second gripping members and the other pair of first and second gripping members are orthogonal to each other, and so that one pair of first and second gripping members can contact the long side of the object from the outside, and the other pair of first and second gripping members can contact the short side of the object from the outside (the same applies to squares and circles). This reduces the burden on each gripping member, thereby reducing running costs and enabling the object to be gripped more stably and reliably.

[0037] As described above, by using the gripping device of the present invention, an object can be gripped stably and reliably with a simple configuration.

[0038] Although the present invention has been described above with reference to one embodiment, the present invention is not limited to the configuration described in the above embodiment and includes other embodiments and modifications that are conceivable within the scope of the claims. For example, a gripping device of the present invention that is constructed by combining some or all of the above-described embodiments and modifications is also within the scope of the present invention. In the above embodiment, both the first and second gripping members are configured with a plurality of elastically deformable pressing portions arranged adjacent to the base portion in the vertical and horizontal directions. However, only one of the first and second gripping members may have the above configuration. In this case, the other of the first and second gripping members may be a conventionally known gripping member, such as a gripping member having only a force constraint function (e.g., JP 2020-28920 A, etc.) or a gripping member having both force constraint and shape constraint functions (e.g., JP 6883908 A, etc.).

[0039] Furthermore, in the above embodiment, a case has been described in which a plurality of elastically deformable pressing portions are arranged adjacently in a vertical and horizontal direction over the entire surface of the base portion of both the first and second gripping members. However, for example, a plurality of elastically deformable pressing portions can be arranged adjacently in a vertical and horizontal direction in the upper region (or lower region) of the base portion, and a contact portion having only the above-mentioned conventionally known force constraint function, or a contact portion having both force constraint and shape constraint functions, can also be arranged in the lower region (or upper region) of the base portion. Furthermore, in the above embodiment, the case where both the first and second gripping members are simultaneously moved in a direction away from or toward each other by the position adjustment means has been described, but it is also possible to configure either one of the first or second gripping members to be movable, while the other of the first or second gripping members is fixed and does not move. [Industrial Applicability]

[0040] INDUSTRIAL APPLICABILITY The present invention is industrially useful because it can provide a gripping device that can stably and reliably grip an object with a simple configuration. [Explanation of symbols]

[0041] 10: gripping device, 11: robot arm, 12, 12a: first gripping member, 13: second gripping member, 14, 14a: object, 15: attachment means, 16: position adjustment means, 17: base portion, 18, 18a, 18b: pressing portion

Claims

1. A gripping device that grips an object using first and second gripping members that face each other with a gap therebetween, The distance between the first and second gripping members is adjustable by a position adjusting means, A gripping device characterized in that either one or both of the first and second gripping members comprises a planar base portion and a plurality of pressing portions attached and fixed in an upright state to the base portion and capable of contacting the object, each pressing portion being arranged adjacent to the base portion vertically and horizontally and capable of elastically deforming individually when the object is gripped by the first and second gripping members.

2. 2. The gripping device according to claim 1, wherein the tip of the pressing part has a hemispherical shape.

3. 2. The gripping device according to claim 1, wherein the pressing portion has a lattice structure.

4. 2. The gripping device according to claim 1, wherein the plurality of pressing portions are configured with different hardnesses.

5. 2. The gripping device according to claim 1, wherein the pressing portion is detachable from the base portion.

6. 2. The gripping device according to claim 1, wherein the pressing portion is made of a single material.

7. 2. The gripping device according to claim 1, wherein the device has a plurality of pairs of the first and second gripping members, and each of the plurality of pairs of the first and second gripping members is arranged so that it can grip the object from around the center.

8. 2. The gripping device according to claim 1, wherein the base portion is disposed at an angle such that the axes of the pressing portions face obliquely upward.

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