Gripper

Abstract

To provide a gripper which has high holding force while flexibly gripping a gripping object.SOLUTION: A gripper has a claw member 11, and a grip member 12. The grip member 12 includes a plate-like resin elastic member 131. The elastic member 131 has a flat-plate-like base part 132, and a plurality of hollow protrusions 133 having a hollow part. The hollow protrusions 133 are protrusively formed so as to be scattered on a base part 132. The hollow protrusion 133 has a first rising part 134 which is erected from the base part 132 and has a hollow cylindrical shape, a plate-like annular part 135 provided from the tip of the first rising part 134 so as to reduce its diameter, and a second rising part 136 which is erected from the inner peripheral side of the annular part 135 in a direction away from the base part. An inner diameter D1 of the first rising part 134 is set to be larger than an outer diameter D2 of the second rising part 136, when the gripping object is gripped, a part of the second rising part 136 enters into the inside of the first rising part 134.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a gripper used for industrial robots and the like, particularly a gripper that grips a work object by an opening / closing operation.

Background Art

[0002] In recent years, industrial robots have been used in various applications such as member conveyance and assembly. Industrial robots for so-called material handling that convey work objects have also been put into practical use. When a work object is conveyed by an industrial robot, a gripper (sometimes called an end effector) is attached to the arm of the industrial robot, and the work object is manipulated by the gripper. Depending on the nature and shape of the work object, different grippers are used. Examples of grippers that grip a work object by an opening / closing operation include those disclosed in Patent Document 1. The gripper of Patent Document 1 has a leaf spring and a cushion material that are opened and closed by an actuator. According to this gripper, it is disclosed that objects with fragile mechanical properties can be gripped and conveyed.

[0003] As a gripper that grips a work object by an opening / closing operation, for example, the one disclosed in Patent Document 1 is known. The gripper of Patent Document 1 has a leaf spring and a cushion material that are opened and closed by an actuator. According to this gripper, it is disclosed that objects with fragile mechanical properties can be gripped and conveyed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The gripper described in Patent Document 1 uses cushioning material in the part of the gripper that grips the object to be gripped (the object to be transported), which reduces the impact force during gripping. However, on the other hand, the holding force during gripping simply depends on the frictional force between the cushioning material and the object to be gripped. Therefore, as shown in Figure 12, the holding force is weak in the direction intersecting the gripping direction, which presents a problem in that the object to be gripped is likely to fall or the position and orientation of the gripped object may change.

[0006] The object of the present invention is to provide a gripper that can flexibly grip an object to be gripped while also providing high holding power. [Means for solving the problem]

[0007] As a result of diligent research, the inventors discovered that by configuring the grip member to include a plate-shaped elastic member having multiple hollow protrusions or hollow ridges with a specific structure, the holding force can be increased while flexibly gripping the object to be held, thus completing the present invention.

[0008] The present invention relates to a gripper having a claw member that is openable and closable for gripping an object to be gripped, and a grip member attached to the claw member so as to contact the object to be gripped when gripping the object, wherein the grip member includes a plate-shaped elastic member made of resin, the elastic member has a flat base and a plurality of hollow protrusions having a hollow portion, the hollow protrusions are formed to protrude so as to be scattered on the base, the hollow protrusions have a hollow cylindrical first rising portion erected from the base, a plate-shaped annular portion that is provided so as to decrease in diameter from the tip of the first rising portion, and a second rising portion erected from the inner circumference side of the annular portion in a direction away from the base, the inner diameter of the cylindrical first rising portion is larger than the outer diameter of the second rising portion, and the hollow protrusions are arranged in a stepped shape so that when gripping an object to be gripped, the hollow protrusions are compressed and a part of the second rising portion enters the inside of the first rising portion (First Invention).

[0009] Furthermore, the present invention relates to a gripper having a claw member that is openable and closable for gripping an object to be gripped, and a grip member attached to the claw member so as to contact an object to be gripped when gripping an object, wherein the grip member includes a plate-shaped elastic member made of rubber or elastomer, the elastic member has a flat base and a plurality of hollow protrusions having a hollow portion, the hollow protrusions are formed to protrude outwards from the base, and the hollow protrusions are erected from the base The gripper has a hollow first protrusion, a plate-shaped step extending from the tip of the first protrusion toward the center of the protrusion, and a second protrusion erected from the center of the protrusion of the step in the direction away from the base, wherein the inner width of the cylindrical first protrusion is greater than the outer width of the second protrusion, and the hollow protrusion is stepped so that when gripping an object, the hollow protrusion is compressed and a part of the second protrusion fits inside the first protrusion (Second Invention).

[0010] In the first or second invention, preferably, the grip member further has a gripping layer located between the elastic member and the object to be gripped (third invention). Also, in the first or second invention, preferably, the elastic member is arranged such that its base is on the side of the claw member (fourth invention). Also, in the first or second invention, preferably, the hollow projection or hollow ridge is provided with a through hole that connects the outside of the hollow projection or hollow ridge to the hollow portion (fifth invention). Also, in the first or second invention, preferably, a communication passage is provided between adjacent hollow projections or hollow ridges that connects the hollow portions of the hollow projections or hollow ridges to each other (sixth invention). [Effects of the Invention]

[0011] According to the gripper of the present invention (first and second inventions), the effect of flexibly gripping the object to be gripped and increasing the holding force can be obtained. Furthermore, according to the third or fourth invention, the holding force can be further increased, and according to the fifth or sixth invention, the grip member can be made more flexible, the resilience of the elastic member is particularly improved, and the flexibility when gripping repeatedly is particularly excellent. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram of an industrial robot equipped with the gripper of the present invention. [Figure 2] This figure shows the configuration of the gripper of the present invention. [Figure 3] This is a cross-sectional view showing the structure of the claw member and grip member of the gripper according to the first embodiment of the present invention. [Figure 4] This is a perspective view of the elastic member in the gripper according to the first embodiment of the present invention. [Figure 5] This is a cross-sectional view of the hollow projection in the gripper according to the first embodiment of the present invention. [Figure 6] This is a cross-sectional view showing the deformation of the gripping member when gripping an object with the gripper of the first embodiment of the present invention. [Figure 7] This figure shows other examples of the shape and arrangement of hollow protrusions. [Figure 8] This is a cross-sectional view showing another example of a hollow projection. [Figure 9] This is a cross-sectional view showing a modified example of the positional relationship between the claw member and the elastic member. [Figure 10] These are a front view and a cross-sectional view of an elastic member used in a gripper according to a second embodiment of the present invention. [Figure 11] These are a front view, a cross-sectional view, and a perspective view of the elastic member used in the gripper of the third embodiment of the present invention. [Figure 12] This figure shows the deformation of the cushioning material when an object is gripped by a conventional gripper. [Modes for carrying out the invention]

[0013] With reference to the following drawings, embodiments of the invention will be described by taking as an example a gripper attached to an industrial robot. Note that the invention is not limited to the individual embodiments shown below, and it can also be implemented with modifications to the forms. For example, the gripper of the present invention can be used not only for industrial robots but also for robots used in homes, hospitals, etc.

[0014] FIG. 1 is a schematic diagram of an industrial robot to which a gripper 10 according to the first embodiment of the present invention is attached. The gripper 10 is attached to and used at the tip of an arm A of the robot. The specific form and configuration of the robot arm are not particularly limited. The arm A may be an articulated arm or a parallel movement arm.

[0015] FIG. 2 is a diagram showing the configuration of the gripper 10 of the present invention. The gripper of the present invention can grip a gripping object 99 (also described as a work object) by an opening and closing operation, and an industrial robot equipped with the gripper of the present invention can grip and transport the gripping object.

[0016] The gripper 10 has a drive unit 19 and claw bases 18, 18. The claw bases 18, 18 are opened and closed by a power device (e.g., a motor or a pressure cylinder, etc.) and a mechanism (e.g., a reduction mechanism, a link, a cam, etc.) provided in the drive unit 19, and the claw members 11, 11 and the grip members 12, 12 described later are opened and closed. For example, in the present embodiment, an electric motor and a ball screw are combined to configure the drive unit 19 such that the claw bases 18, 18 are opened and closed in parallel. Note that the specific configuration and mechanism of the drive unit 19 and the claw bases 18 are not particularly limited, and they may be those that open and close the claw members and the grip members in parallel, or those that open and close in a compass shape. Also, the claw bases 18, 18 are not essential, and the claw members 11, 11 described later may be directly driven to open and close by the drive unit 19. If there are claw bases 18, 18, it is convenient to easily replace the claw members 11 and the grip members 12 in the gripper 10.

[0017] The gripper 10 has claw members 11, 11 and grip members 12, 12. The claw members 11 are provided to be openable and closable so that the gripper 10 can grip the object to be gripped 99. In this embodiment, the claw members 11 are attached to the claw base 18 by screws or the like so that they can be opened and closed. The grip members 12 are attached to the claw members 11 and open and close together with the claw members. The grip members 12 are also provided to be in direct contact with the object to be gripped 99 when gripping the object to be gripped 99.

[0018] The direction in which the claw member 11 and the grip member 12 move in conjunction with the gripping operation of the gripper 10 is hereinafter referred to as the "gripping direction." In Figure 2, the gripping direction is the left-right direction in the figure. Furthermore, in this embodiment, two claw members 11 and two grip members 12 are provided in pairs. As a result, an object to be gripped placed between the grip members 12, 12 is gripped between the grip members 12, 12 as the distance between the claw members 11, 11 narrows. The number of claw members 11 and grip members 12 is not limited to two; there may be one, three or more.

[0019] The configuration of the claw member 11 and the grip member 12 will be explained in more detail below. Figure 3 is a cross-sectional view showing the structure of the claw member 11 and grip member 12 in the gripper 10 of the first embodiment. The upper left view of Figure 3 is a cross-sectional view from the viewpoint corresponding to the left claw member 11 and grip member 12 in Figure 2. In the upper left view of Figure 3 and the lower left view of Figure 3 (XX cross-sectional view), the gripping direction is the left-right direction of the figure, while in the upper right view of Figure 3 (YY cross-sectional view), the gripping direction is the depth direction of the paper.

[0020] The claw member 11 is made of a material harder than the grip member 12, such as metal or plastic, so that the opening and closing motion of the claw base 18, provided by the drive unit 19, is well transmitted to the grip member 12. Although not essential, it is preferable that the claw member 11 is configured such that when gripping is performed by the gripper 10, the grip member 12 is sandwiched between the claw member 11 and the object to be gripped 99, and the claw member 11 pushes the object to be gripped 99 via the grip member 12.

[0021] The grip member 12 is more flexible than the claw member 11, and when the gripper 10 grips the object 99, the grip member 12 deforms as the object 99 is gripped. The grip member 12 includes an elastic member 131. Although not essential, the grip member 12 preferably also includes a gripping layer 121. When the gripping layer 121 is provided, the grip member 12 is configured such that the gripping layer 121 and the elastic member 131 are arranged in order from the side of the object to be gripped (99).

[0022] The elastic member 131 is made of resin so as to have flexibility that allows it to elastically deform when gripping the object 99. The resin constituting the elastic member 131 may be rubber, a thermoplastic elastomer, a thermoplastic resin, or a thermosetting resin. Although not limited, typically the resin constituting the elastic member 131 is rubber or an elastomer, and its hardness is preferably about 50 to 85 degrees on the Duro A hardness scale. Also, although not essential, preferably, as in this embodiment, the hardness of the resin constituting the elastic member 131 is higher than the hardness of the resin constituting the gripping layer 121.

[0023] The elastic member 131 is plate-shaped. The elastic member 131 has a flat base 132 and a plurality of hollow protrusions 133, 133 having hollow portions. The hollow protrusions 133, 133 are formed to protrude from the base 132 so as to be scattered at predetermined intervals. In this embodiment, the hollow protrusions 133, 133 are arranged in a grid pattern of orthogonal intersections. Although not essential, in this embodiment, the elastic member 131 is attached to the claw member 11 such that the base portion 132 is located on the claw member 11 side and the tip (one end) 131a of the protruding hollow projection 133 is located on the gripping object (99) side.

[0024] Figure 4 shows a perspective view of an elastic member 131 with multiple hollow protrusions 133, 133 erected on its base 132. Figure 5 shows the cross-sectional structure of the hollow protrusions 133 of the elastic member 131. The hollow projection 133 has a first rising portion 134, a plate-shaped annular portion 135, and a second rising portion 136.

[0025] The first rising portion 134 is erected in a cylindrical shape so as to rise from the flat base portion 132 in the thickness direction of the base. The internal space of the cylindrical first rising portion 134 is the hollow portion of the hollow projection 133. The first rising portion 134 is typically provided in a cylindrical shape. The first rising portion 134 may also be rectangular in shape. The first rising portion 134 may also be provided in a tapered shape.

[0026] The plate-shaped annular portion 135 is provided so as to decrease in diameter from the tip (134a) of the first rising portion 134. In this embodiment, the annular portion 135 is provided in a flat plate shape that is substantially parallel to the base portion 132. The annular portion 135 may also be provided in a conical shape such that its inclination with respect to the base portion 132 is within plus or minus 30 degrees.

[0027] The second rising portion 136 is erected from the inner circumference 135a of the annular portion 135 in a direction away from the base portion 132 and toward the object to be gripped (99). The second rising portion 136 may be hollow cylindrical, solid columnar, or hemispherical. In this embodiment, the second rising portion 136 is provided in a hollow cylindrical shape, and the tip of the second rising portion (the tip portion 131a of the hollow projection 133) is closed in a flat plate shape. The second rising portion 136 may also be rectangular tubular, and its tip may be open. Furthermore, the tip may be flat, spherical, or the like.

[0028] The inner diameter D1 of the cylindrical first rising portion 134 is larger than the outer diameter D2 of the second rising portion 136. When gripping an object, the hollow projection is compressed in the thickness direction of the elastic member 131. At that time, the hollow projection 133 is a stepped hollow projection so that a part of the second rising portion 136 fits inside the cylindrical first rising portion 134.

[0029] Although not essential, in this embodiment, the elastic member 131 is constructed by integrally molding a base portion 132 and a hollow projection 133 into a single continuous sheet. That is, a hole is made in the base portion 132 where the hollow projection 133 is provided, and this hole allows air to flow between the hollow portion of the hollow projection 133 and the outside. An elastic member 131 of this form can be molded by injection molding, vacuum forming, press molding, etc.

[0030] Although not essential, the grip member 12 may have a gripping layer 121, as in this embodiment. The gripping layer 121 is a layer provided to be in contact with the object to be gripped. The outer surface of the gripping layer 121 will hereafter be referred to as the gripping surface 12S. The gripping layer 121 is a flat, plate-shaped layer. Preferably, the gripping layer 121 is made of a resin with a duro A hardness of 30 to 80 HDA in accordance with JIS-K6253. When the gripping layer 121 is made of resin, the resin constituting the gripping layer 121 may be a rubber or thermosetting resin such as silicone rubber, acrylonitrile butadiene rubber, or urethane rubber; it may be a thermoplastic elastomer such as an olefin-based thermoplastic elastomer or a styrene-based thermoplastic elastomer; or it may be a thermoplastic resin such as soft polyvinyl chloride resin or vinyl acetate resin (EVA resin). Various additives and fillers may be blended into these resins as needed.

[0031] The material constituting the gripping layer 121 is not limited to resin. Furthermore, even if the material constituting the gripping layer 121 includes a somewhat rigid material, if the thickness of the gripping layer 121 is made thin, for example to 0.3 to 1.5 mm, the gripping layer 121 can be made to deform flexibly in the gripping direction. Examples of other materials or components constituting the gripping layer include, for example, materials made by coating or impregnating fabric with resin (e.g., artificial leather or tarpaulin), or laminated materials made by laminating fabric (woven or nonwoven), paper, or resin sheets. Of course, the gripping layer 121 may also be composed of a single layer.

[0032] Furthermore, although not required, in this embodiment, the elastic member 131 is provided such that the tip 131a of the hollow projection abuts against the gripping layer 121. Although not required, the elastic member 131 may be bonded to the gripping layer 121. Alternatively, the elastic member 131 may be attached to, welded to, or integrally molded with the gripping layer 121.

[0033] The elastic member 131 is positioned behind the gripping layer 121, in contact with the gripping layer 121. As a result, the areas where the tip 131a of the hollow projection of the elastic member 131 contacts the gripping layer 121, and the areas where the elastic member 131 does not contact the gripping layer 121, are distributed in an island-like pattern along the gripping direction. The gripping layer 121 can deform flexibly in the gripping direction, but in the areas in contact with the elastic member 131, the gripping layer 121 is supported by the elastic member 131, and its deformation in the gripping direction is restricted. This combination of island-like structure and gripping layer contributes to increased flexibility and holding power.

[0034] Furthermore, although not essential, preferably, the grip member 12 is configured to include an outer shell member 120, as in this embodiment. In this embodiment, the outer shell member 120 is a hollow structure member configured such that a part of it becomes the gripping layer 121. Preferably, the elastic member 131 is placed inside the outer shell member 120 (in the hollow part of the hollow structure).

[0035] Furthermore, although not essential, preferably as in this embodiment, the grip member 12 is provided with a vent 124 that allows air inside the outer shell member 120 to escape to the outside when gripping an object 99. The provision of the vent 124 promotes flexible deformation of the grip member 12 when gripping an object. In this embodiment, one side of the hollow box-shaped outer shell member 120 is removed, and that portion becomes a ventilation opening 124. The specific form of the ventilation opening may be other forms.

[0036] Although not required, the outer shell member 120 of the grip member 12 in this embodiment may have the following form. The outer shell member 120 is integrally molded into a box-shaped hollow form having a flat wall that becomes the gripping layer 121 (hereinafter also referred to as the "gripping wall") and side walls 122, 123. Here, the side walls 122 and 123 are wall portions that extend along the opening and closing direction (gripping direction) of the gripping operation, and the side walls 122 and 123 extend in the direction opposite to the gripping object 99 relative to the gripping wall (121). The side walls 122 and 123 that extend along the gripping direction are preferably provided in the shape of a flat plate or a cylindrical shape.

[0037] The flat gripping layer 121 does not need to be perfectly flat; even if it is a slightly bulging or concave curved surface or a spherical gripping layer, it is included in the category of flat gripping layers as long as it is generally flat. Furthermore, the gripping surface 12S on which the gripping layer 121 contacts the object to be gripped 99 may be provided with a textured surface such as protrusions, holes, raised or recessed grooves, checkering, dot patterns, or a textured surface such as a matte finish, wrinkles, or a grain, in order to adjust the frictional force and surface tackiness. If the gripping surface 12S side of the gripping layer 121 is made of resin, granular materials such as silica particles or rubber particles may be kneaded into the resin so that these granular materials are exposed on the gripping surface 12S. Alternatively, the gripping surface 12S may be provided with a surface layer made of a different material from the gripping wall, such as silicone rubber, EVA resin, nonwoven fabric, or resin film (polyimide film, PET film, etc.).

[0038] The integration (attachment) of the grip member 12 and the claw member 11 is not particularly limited. In this embodiment, the outer skin member 120 is provided with an attachment portion 125 having a bag-shaped hole, and the claw member 11 is inserted into the hole of the attachment portion 125 to integrate the grip member 12 and the claw member 11. Depending on the need to prevent detachment, the outer skin member 120 and the claw member 11 may be screwed together, or they may be fixed together with adhesive, glue, or adhesive tape. Alternatively, the elastic member 131 and the gripping layer 121 may be sequentially integrated with the claw member 11 using an adhesive or the like to constitute the grip member 12 while integrating them with the claw member 11.

[0039] A method for manufacturing components and other parts that make up the gripper 10 described above will be explained. The drive unit 19, the claw base 18, the claw member 11, etc., can be manufactured in the same way as conventionally known components of industrial robots. The gripping layer 121 (outer skin member 120) of the grip member 12 can be manufactured by injection molding or casting of rubber material or thermoplastic elastomer material. The elastic member 131 of the grip member 12 can be manufactured by injection molding of rubber material or thermoplastic elastomer material, or by press-forming a sheet of rubber material or thermoplastic elastomer material. The grip member 12 can be obtained by pushing the obtained elastic member 131 inside the outer skin member 120 and integrating them so that they do not come apart.

[0040] The effects and benefits of the gripper 10 of the first embodiment described above will now be explained. According to the gripper 10 described above, when gripping an object 99, the hollow protrusions 133, 133 of the elastic member 131 deform into a specific shape to grip the object 99, thereby allowing for flexible gripping of the object while increasing the holding force. Furthermore, if the object can be gripped flexibly, it becomes possible to grip objects of various shapes in various positions, thereby increasing the robustness of the gripping operation.

[0041] Here, the holding force when gripping the object 99 is the magnitude of the force that can resist moving the object in a direction perpendicular to the gripping direction (for example, the up and down direction in Figure 2). If the holding force is small, the object 99 is likely to fall even if you try to lift it vertically upward in the gripper position shown in Figures 1 and 2.

[0042] Figure 12 shows a gripper equipped with conventional cushioning material (e.g., urethane sponge) 82,82 at the tips of claw members 81,81, as described in Patent Document 1. However, in such conventional technology, the holding force relies solely on the frictional force between the cushioning material 82 and the object to be gripped. Therefore, if the cushioning material 82 is flexible, it tends to deform in a direction perpendicular to the gripping direction, reducing the holding force, causing the object to slip and easily fall off. In other words, conventionally known cushioning materials have not been able to improve both the flexibility of the cushioning material and the holding force of the gripper.

[0043] Figure 6 schematically shows the shape changes of the elastic member 131 and the gripping layer 121 before and after gripping the object to be gripped. Figure 6(a) shows the state before gripping, and Figure 6(b) shows the state after gripping. In the gripper 10 of the first embodiment described above, the grip member 12 has a plate-shaped elastic member 131 having a plurality of hollow protrusions 133, 133 having hollow portions, and the hollow protrusions 133, 133 are formed to protrude from the base 132 so as to be scattered at predetermined intervals, and the hollow protrusion 133 has a hollow cylindrical first rising portion 134, a plate-shaped annular portion 135 that is provided so as to decrease in diameter from the tip of the first rising portion, and moves away from the base The hollow projection 133 has a second rising portion 136 erected from the inner circumference side of the annular portion in the direction of the first rising portion 134, and furthermore, in the hollow projection 133, the inner diameter D1 of the cylindrical first rising portion 134 is larger than the outer diameter D2 of the second rising portion 136 (i.e., D1 > D2), so that when gripping an object, the hollow projection 133 is compressed and a part of the second rising portion 136 fits inside the first rising portion 134, thus forming a stepped hollow projection.

[0044] With this configuration, when gripping an object, the annular portion 135 deforms to promote deformation of the columnar member 133 in the gripping direction, and as shown in Figure 6(b), the hollow projection 133 compresses and deforms so that the second rising portion 136 enters the hollow portion inside the first rising portion 134 from below. Therefore, the hollow projection 133 becomes flexible in the gripping direction (up and down direction in Figure 6) and can flexibly follow the movement of the object being gripped.

[0045] Furthermore, in Figure 6(b), when the object to be gripped is gripped, the protruding portion of the object to be gripped 99 fits between the hollow projections 133, 133, which are provided at predetermined intervals, that is, into the sea portion of the sea-island structure, and the object to be gripped 99 is gripped by the gripper 10. In this state, even if the object to be gripped tries to slip out in the lateral direction of Figure 6, the hollow projections 133 catch on the object to be gripped, thereby increasing the holding force. Furthermore, in the hollow projection 133, the inner diameter D1 of the cylindrical first rising portion 134 is larger than the outer diameter D2 of the second rising portion 36. When gripping an object, the hollow projection 133 can be compressed and deformed so that the second rising portion 136 fits into the hollow portion inside the first rising portion 134. As a result, the second rising portion 136 is supported by the first rising portion 134 in the lateral direction as shown in Figure 6, and the rigidity of the tip 131a of the columnar member 133 (lateral rigidity in Figure 6) is increased. This makes it more reliable to prevent the columnar member from tipping over and the object from slipping out even if a force is applied in the direction that would cause the gripped object to slip out from the gripping state shown in Figure 6(b). In other words, the holding force is increased.

[0046] The inventors conducted comparative tests of the holding force of the gripper of the first embodiment described above. To ensure that the gripping force is equivalent to that of the gripper stroke in the gripping direction, that is, that the flexibility in the gripping direction is equivalent, an example sample corresponding to the gripper of the first embodiment and a comparative example sample were prepared. In the comparative example sample, the outer shell member and claw member are equivalent to those of the example sample, but a flat, elastic member made of gel material is inserted inside the outer shell member. When a spherical object was gripped with a gripping force of 80N, and the object was displaced in a direction to be pulled out of the gripper, the holding force to prevent it from coming loose was measured. The example sample showed a holding force of 94N, while the comparative example sample showed a holding force of 48N. The gripper 10 of the above embodiment is flexible yet has a high holding force.

[0047] As described above, the gripper of the first embodiment allows for flexible gripping of the object to be gripped while increasing the holding force. In the description of the above embodiment, an example was shown in which a gripping layer 121 is placed between the elastic member 131 and the object to be gripped (99), but the above effect also occurs in embodiments without a gripping layer, as shown in Figure 9.

[0048] Furthermore, as with the gripper 10 of the first embodiment described above, when a gripping layer 121 is present, as shown in Figure 6(b), the gripping layer 121 deforms to adhere closely to the surface of the object to be gripped (99), thereby generating a sufficiently large frictional force between the gripping layer 121 and the object to be gripped 99, and particularly enhancing the holding force.

[0049] From the viewpoint of further increasing the holding force, it is preferable that the gripping layer 121 is made of resin with a Duro A hardness of 30 to 80 HDA in accordance with JIS-K6253, and that the elastic member is also made of resin, with the hardness of the resin constituting the elastic member being higher than the hardness of the resin constituting the gripping layer and the hardness of the resin constituting the support. This is because, in this configuration, the grip member 12 becomes more flexible, and the part that the elastic member 131 contacts firmly supports the gripping layer 121 from the back, making it easier for the gripping layer 121 to catch on the object 99, thereby increasing the holding force.

[0050] Furthermore, although not essential, the holding force is particularly enhanced when the elastic member 131 is positioned such that its base 132 faces the claw member 11, as in the gripper 10 of the first embodiment described above, and as shown in Figure 9(a). This is because, in such a configuration, the protruding portion of the object to be gripped can easily fit into the hollow protrusions 133, 133 that are scattered at predetermined intervals. Furthermore, if the base portion 132 is flexible, the holding force can be sufficiently increased even if the elastic member 131 is positioned so that the base portion 132 of the elastic member 131 faces the object to be gripped (99), as shown in Figure 9(b).

[0051] Furthermore, from the viewpoint of easily integrating the elastic member 131 with the gripping layer 121, it is preferable that, as in this embodiment, the grip member 12 is configured to include an outer shell member 120, the outer shell member 120 is configured to have a hollow structure such that a part of the outer shell member 120 becomes the gripping layer 121, and the elastic member 131 is arranged inside (in the hollow part) of the outer shell member 120.

[0052] Furthermore, from the viewpoint of further increasing the holding force, as in this embodiment, it is preferable that the hollow protrusions 133, 133 of the elastic member be provided in pairs so as to sandwich the area in which the object to be gripped 99 contacts the grip member 12 when viewed along the opening and closing direction of the gripping operation. When the hollow protrusions 133, 133 are provided in pairs in this way, the hollow protrusions 133, 133 deform to sandwich the object to be gripped 99 and support the object to be gripped 99, thereby particularly increasing the holding force.

[0053] The invention relating to the gripper 10 of the first embodiment described above is not limited to the above embodiment and can be implemented with various modifications. Other embodiments of the invention will be described below, but in the following description, the focus will be on the parts that differ from the above embodiment, and parts that are the same will be described with the same number and their detailed description will be omitted. Furthermore, these embodiments can be implemented by combining or substituting parts of each other.

[0054] The specific configuration of the elastic member 131 in the above embodiment can be changed. In the description of the first embodiment above, an example was given of an elastic member 131 in which the hollow protrusions 133, 133 are arranged on the intersections of an orthogonal grid. However, the planar pattern in which these hollow protrusions 133, 133 are arranged when viewed along the gripping direction may be a planar pattern in which the hollow protrusions 133, 133 are located at the vertices when a hypothetical tile of triangles or hexagons is formed. Figure 7 illustrates modified forms of the elastic member, including modified forms of the hollow protrusions 133, 133 and their planar patterns when viewed along the gripping direction. Figure 7(a) shows an example in which stepped cylindrical hollow protrusions 133, 133 are arranged in a planar pattern resembling a tile of equilateral triangles. Figure 7(b) shows an example in which stepped rectangular tubular hollow protrusions 133', 133' are arranged in a planar pattern resembling a tile of regular hexagons. Furthermore, the hollow protrusions 133, 133 may be randomly scattered on the base.

[0055] The hollow projections 133, 133 are provided to extend and protrude in a direction along the gripping direction, but the direction of extension of the hollow projections 133, 133 may be inclined with respect to the gripping direction or the normal to the gripping surface 12S. When the hollow projections 133, 133 are provided inclined, it is preferable that they are inclined in a direction from the tip portion 11t of the claw member 11 toward the root portion of the claw member as one moves from the claw member 11 toward the gripping layer 121.

[0056] Figure 8 shows another modified example of the hollow projection. Figure 8 shows a cross-section of the hollow projection in the elastic member. The vertical direction in the figure is the gripping direction. As with the hollow projection 133X of the embodiment in Figure 8(a), the portion 136X corresponding to the second rising portion of the hollow projection may be solid. Even with such a hollow projection 133X, if the inner diameter of the cylindrical first rising portion 134X is larger than the outer diameter of the second rising portion 136X, and the hollow projection is compressed when gripping an object to be gripped, causing a part of the second rising portion 136X to enter the inside of the first rising portion 134X, then a stepped hollow projection will similarly be able to flexibly grip the object to be gripped and increase the holding force in the direction perpendicular to the gripping direction.

[0057] Furthermore, as shown in the embodiment of Figure 8(b), the hollow projection 133Y may be a three-tiered hollow projection, with a smaller diameter third rising portion 137Y erected from the tip of the second rising portion 136Y. Even with such a hollow projection 133Y, if the inner diameter of the cylindrical first rising portion 134Y is larger than the outer diameter of the second rising portion 136Y, and the hollow projection is compressed when gripping an object, causing a part of the second rising portion to enter the inside of the first rising portion, a stepped hollow projection will similarly be formed, resulting in the ability to flexibly grip an object and increase the holding force in a direction perpendicular to the gripping direction. In this case, the second rising portion 136Y is also hollow, and the inner diameter of the hollow cylindrical second rising portion 136Y is larger than the outer diameter of the third rising portion 137Y. When gripping an object, the hollow projection is compressed, and a part of the third rising portion fits inside the second rising portion. This further improves flexibility and is preferable.

[0058] Furthermore, as shown in the embodiment of Figure 8(c), it is preferable that the hollow projection is provided with a protruding portion 137 that extends from the portion where the second rising portion 136Z and the annular portion 135Z connect toward the hollow portion of the first rising portion 134Z. By providing the protruding portion 137, the flexibility of the columnar member is increased, and during the gripping operation, the protruding portion 137 comes into contact with the claw member 11, allowing the gripping force to be sufficiently increased and the holding force to be enhanced.

[0059] Figure 9 shows an embodiment of the gripper 10 of the first embodiment described above, in which a gripping layer is not provided. In the example in Figure 9(a), the elastic member 131 is attached to the claw member 11 to constitute the gripper. In the example in Figure 9(b), the elastic member 131 is attached to the claw member 11 in an orientation such that the side of the base 132 faces the side of the object to be gripped (99) to constitute the gripper. In both embodiments of Figures 9(a) and (b), the effect is obtained that the object to be gripped can be gripped flexibly, and the holding force in the direction perpendicular to the gripping direction can be increased.

[0060] Figure 10 shows a front view and a cross-sectional view of the elastic member 231 used in the gripper of the second embodiment. This elastic member 231 can constitute the gripper in a similar manner to the elastic member 131 of the first embodiment. The elastic member 231 shown in Figure 10 has hollow protrusions 233, 233 having hollow portions in a predetermined planar pattern projecting from a flat base portion 232, and the hollow protrusions 233, 233 are similarly stepped hollow protrusions, just like the elastic member 131 of the first embodiment. In the elastic member 231 shown in Figure 10, further, connecting passages 238, 238 are provided between adjacent hollow protrusions 233, 233 to connect the hollow portions 237, 237 of the hollow protrusions to each other. In particular, in this embodiment, the connecting passages are formed to connect the side walls of the hollow cylindrical first rising portion 234 in a tunnel-like manner.

[0061] With this configuration, in the elastic member 231 of this embodiment, the hollow portions of the hollow protrusions 233, 233 are in communication with each other, allowing air to flow between them. Without these communication passages, when a hollow protrusion with a hollow portion is compressed during a gripping operation, even after the air inside the hollow protrusion escapes and the grip is released, the base of the compressed hollow protrusion tends to stick to the claw member side like a suction cup, preventing the contracted state of the hollow protrusion from being released. In such a state, the grip member may become stiff when gripping and releasing are repeated continuously, potentially leading to unstable gripping. On the other hand, with the elastic member 231 of this embodiment, communication passages 238, 238 are provided between the hollow portions, allowing air to flow between them. This allows air to be managed within the internal space of the hollow protrusions, preventing them from sticking like a suction cup when the grip is released. Therefore, by providing such an elastic member 231, the resilience of the elastic member becomes particularly good, and the flexibility of the grip member when repeatedly gripping becomes particularly excellent. Furthermore, the presence of such connecting passages prevents air from being trapped in the hollow portion of the hollow projection 233, which would otherwise act like an air spring. This allows the grip material to be made more flexible.

[0062] From the viewpoint of improving the resilience of the elastic member, it is particularly preferable that the communication passages 238, 238 be provided so as to reach the peripheral edge 231E of the elastic member 231, allowing communication with the outside air, thereby connecting the internal spaces of the hollow protrusions to each other and further allowing communication with the outside air.

[0063] Furthermore, when connecting passages 238, 238 are provided, it is preferable to provide tunnel-shaped connecting passages at more positions, and especially preferably at all positions, between adjacent hollow protrusions 233, 233. Since the tunnel-shaped walls defining the connecting passages have the function of supporting the cylindrical first rising portions 234, 234 in the lateral direction, the more connecting passages 238, 238 are provided, the less likely the first rising portions 234, 234 are to tip over laterally, and as a result, it becomes possible to increase the holding force while increasing the flexibility of the grip member.

[0064] Furthermore, from the viewpoint of improving the resilience of the elastic member, through holes 139, 139 connecting the outside of the hollow projection and the hollow portion 138 may be provided in the hollow projection, as shown in the cross-section of the hollow projection 133Y in Figure 8(b). Even with such a configuration, the tendency to stick like a suction cup when the grip is released is suppressed, the resilience of the elastic member is particularly improved, and the flexibility of the grip member when repeatedly gripping is particularly excellent. Furthermore, the presence of such through holes prevents air from being trapped in the hollow portion of the hollow projection 133Y, which would otherwise act like an air spring. This allows the grip material to be made more flexible.

[0065] Figure 11 shows a front view, cross-sectional view, and perspective view of an elastic member 331 used in the gripper of the third embodiment. This elastic member 331 can constitute the gripper 10 in a similar manner to the elastic member 131 of the first embodiment. The elastic member 331 shown in Figure 11 has a flat base portion 332 and a plurality of hollow protrusions 333 having hollow portions. The hollow protrusions 333 are formed to protrude from the base portion 332 so as to be arranged at predetermined intervals. The hollow protrusions 333 may be straight or be bent. In this embodiment, they are curved, particularly arc-shaped. The spacing between the hollow protrusions 333 may be constant, but may vary, and the spacing may differ between each protrusion.

[0066] The hollow protrusion 333 has a hollow first protrusion 334 erected from the base 332, a plate-shaped stepped portion 335 provided extending from the tip of the first protrusion 334 toward the center of the protrusion, and a second protrusion 336 erected from the center side of the protrusion of the stepped portion 335 in a direction away from the base 332. Furthermore, in the hollow protrusion 333, the inner width D3 of the cylindrical first protrusion 334 is larger than the outer width D4 of the second protrusion 336, and the hollow protrusion is stepped so that when gripping an object, the hollow protrusion 333 is compressed and a part of the second protrusion 336 fits inside the first protrusion 334.

[0067] By providing the elastic member 331 with such a configuration, the gripper of the third embodiment, like the first embodiment, can increase the holding force while increasing the flexibility of the grip member.

[0068] In this embodiment, when the hollow protrusions are arranged in an arc shape, it is preferable to attach them to the gripper such that the arcs protrude vertically downwards during the gripping operation. This results in particularly high holding force.

[0069] Furthermore, although not essential, this embodiment also provides connecting passages 338, 338 that connect the hollow portions of adjacent hollow protrusions. The provision of these connecting passages makes the elastic member 331 more flexible and improves the restorative properties of the hollow protrusions 333 when the grip is released.

[0070] Preferably, the elastic member 331 of this embodiment is also used in combination with the gripping layer 121. Furthermore, preferably, the elastic member 331 of this embodiment is attached to the claw member 11 such that the base 332 is located on the side of the claw member 11 and the hollow protrusion 333 protrudes toward the object to be gripped.

[0071] In the above description of the embodiments, the focus has been mainly on forms in which the claw member is made of a rigid material. However, the claw member is not particularly limited, as long as it can transmit the gripping force to the object being gripped via a flexible grip member between the claw member and the object being gripped during gripping. For example, the claw member may be made of a highly rigid material such as metal or hard plastic, but it may also be made of rubber or soft plastic. Furthermore, the claw member may be hollow and its rigidity may be varied by filling it with gas or liquid. In addition, the claw member may have a movable part and be configured to allow for active deformation such as bending.

[0072] The shape and properties of the object to be gripped by the gripper are not particularly limited, as long as it can be gripped. Because the gripper of the above embodiment is highly flexible, it can grip objects of various shapes, such as rectangular parallelepipeds, cylinders, polygonal pyramids, polyhedra, spheres, and ellipsoids, in a variety of positions. [Industrial applicability]

[0073] Grippers can be attached to the end of a robotic arm and used for tasks such as material handling, making them highly valuable for industrial applications. [Explanation of symbols]

[0074] A robotic arm 10 Grippa 11 Claw member 12 Grip component 120 Outer shell member 121 Grasping layer 131 Elastic members 132 Base 133 Hollow protrusion 134 First rise section 135 Ring section 136 Second rise section 99 Grasped object

Claims

1. a claw member that is provided so as to be able to open and close so as to grip an object to be gripped; a gripper having a grip member attached to the claw member so as to come into contact with the object to be gripped when gripping the object, the grip member includes a plate-shaped elastic member made of resin, The elastic member has a flat base and a plurality of hollow protrusions each having a hollow portion. The hollow protrusions are formed so as to protrude from the base portion in a scattered manner, The hollow protrusion is a hollow cylindrical first rising portion erected from the base portion; a plate-shaped annular portion provided so as to reduce in diameter from a tip of the first rising portion; a second rising portion erected from the inner circumferential side of the annular portion in a direction away from the base portion; It has The inner diameter of the cylindrical first rising portion is larger than the outer diameter of the second rising portion, The hollow protrusion is formed in a stepped shape so that, when the object to be grasped is grasped, the hollow protrusion is compressed and a part of the second rising portion enters inside the first rising portion. Gripper.

2. a claw member that is provided so as to be able to open and close so as to grip an object to be gripped; a gripper having a grip member attached to the claw member so as to come into contact with the object to be gripped when gripping the object, the grip member includes a plate-shaped elastic member made of rubber or elastomer, The elastic member has a flat base and a plurality of hollow ridges having hollow portions, The hollow ridges are formed to protrude from the base in a line, The hollow ridges are a hollow first protruding portion erected from the base portion; a plate-like step portion provided from the tip of the first convex strip portion toward the center of the convex strip; a second protruding portion erected from the protruding center side of the step portion in a direction away from the base portion; It has The inner width of the cylindrical first convex portion is larger than the outer width of the second convex portion, The hollow ridges are formed in a stepped shape so that, when the object to be gripped is gripped, the hollow ridges are compressed and a part of the second ridge portion fits inside the first ridge portion. Gripper.

3. The grip member further includes a grip layer positioned between the elastic member and the object to be gripped. The gripper according to claim 1 or 2.

4. The elastic member is arranged so that the base of the elastic member faces the claw member. The gripper according to claim 1 or 2.

5. The hollow protrusion or hollow ridge is provided with a through hole that connects the outside of the hollow protrusion or hollow ridge with the hollow portion. The gripper according to claim 1 or 2.

6. A communication passage is provided between adjacent hollow protrusions or hollow ridges, which connects the hollow portions of the hollow protrusions or hollow ridges to each other. The gripper according to claim 1 or 2.