Gripper

Abstract

While gently gripping the object to be gripped, the position and orientation of the object to be gripped are more accurately controlled. 【Solution means】 The gripper 10 has a claw member 11 provided to be openable and closable, and a grip member 12 attached to the claw member 11. The claw member 11 has a higher rigidity than the grip member 12 so as not to substantially deform during the gripping operation. The grip member 12 includes a plate-shaped elastic member 131 made of rubber or elastomer, and an outer skin member 120 made of rubber or elastomer. The outer skin member 120 has a box-shaped hollow shape including a gripping layer 121 and side walls 122 and 123. The elastic member 131 is arranged so as to be wrapped by the outer skin member 120. The claw member 11 has a rising surface 111 extending along the gripping direction. The rising surface 111 of the claw member and the side wall 122 of the outer skin member face each other, and the movement of the gripping layer 121 is restricted by the contact between the rising surface 111 and the side wall 122.

Description

Technical Field

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

Background Art

[0002] In recent years, industrial robots have been used in various applications such as member transportation and assembly. Industrial robots for so-called material handling that transport work objects have also been put into practical use. When transporting a work object 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. There are grippers that utilize attractive forces such as magnetic force and vacuum suction, and grippers that grip a work object by an opening and closing operation.

[0003] As grippers that grip a work object by an opening and closing operation, for example, those disclosed in Patent Document 1 and Patent Document 2 are 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 the gripper, it is disclosed that objects with fragile mechanical properties can be gripped and transported.

[0004] Also, the gripper of Patent Document 2 utilizes an elastic member having an elastic member with a hollow protrusion of a specific shape. According to the gripper, it is disclosed that while gripping the object to be gripped flexibly, the holding force is high.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the gripper of Patent Document 1, since a cushioning material is used for the portion where the gripper grips the object to be gripped (the object of the conveying operation), the impact force during gripping is alleviated. 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, the holding force is weak in the direction intersecting the gripping direction, and there is a problem that the object to be gripped is likely to fall or the position and posture of the gripped object to be gripped change.

[0007] Also, according to the gripper of Patent Document 2, it is possible to grip the object to be gripped flexibly and increase the holding force. However, even in the gripper of Patent Document 2, there is a demand to more accurately control the position and posture of the object to be gripped.

[0008] An object of the present invention is to provide a gripper that can flexibly grip an object to be gripped and more accurately control the position and posture of the object to be gripped.

Means for Solving the Problems

[0009] As a result of intensive studies, the inventor has found that in a gripper having a claw member and a grip member, the grip member includes an elastic member made of rubber or an elastomer and an outer skin member made of rubber or an elastomer, and the elastic member is configured to be wrapped by the outer skin member. Further, the side wall of the outer skin member faces the rising surface provided on the claw member, and when the gripper is configured such that the movement of the gripping layer of the outer skin member is restricted by the contact between the rising surface and the side wall, the above problems are solved, and the present invention has been completed.

[0010] The present invention relates to a gripper having a claw member provided so as to be openable and closable to grip 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 to be gripped, wherein the claw member has higher rigidity than the grip member so as not to substantially deform during the gripping operation, the grip member includes a plate-shaped elastic member made of rubber or an elastomer, the grip member further includes an outer skin member made of rubber or an elastomer, the outer skin member is formed in a box-shaped hollow shape so as to include a gripping layer positioned between the elastic member and the object to be gripped and side walls extending in the gripping direction, the elastic member is disposed so as to be wrapped by the outer skin member, and the claw member Mounting recess for the grip material and has a rising surface extending along the gripping direction, and the rising surface of the claw member and the side wall of the outer skin member face each other, and the movement of the gripping layer is restricted by the contact between the rising surface and the side wall, which is a gripper (First Invention).

[0011] In the first invention, preferably, the rising surface and the side wall are in contact with each other (Second Invention). Also, in the first invention, preferably, in the length direction or the width direction of the claw member, the rising surface is provided on the claw member with respect to the side walls positioned on both sides of the grip member, respectively (Third Invention). Further, in any one of the first to third inventions, preferably, the elastic member has a flat base portion and a plurality of protrusions, and the protrusions are formed to protrude so as to be scattered on the base portion (Fourth Invention).

Advantages of the Invention

[0012] According to the gripper of the present invention (First Invention), while the object to be gripped can be softly gripped, the position and posture of the object to be gripped can be more accurately controlled.

[0013] Furthermore, when the second or third invention is adopted, the control of the position and posture of the object to be gripped becomes more accurate. Also, when the fourth invention is adopted, the holding force can be increased while accurately controlling the position and posture of the object to be gripped.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0015] Hereinafter, with reference to the following drawings, embodiments of the invention will be described by taking a gripper attached to an industrial robot as an example. Note that the invention is not limited to the individual embodiments shown below, and the form can be changed and implemented. For example, the gripper of the present invention can be used not only for industrial robots (such as assembly robots, transport robots, and collaborative robots) used in manufacturing and distribution industries, but also for robots (such as assistive robots, auxiliary robots, care robots, and prosthetic hands) used in homes and hospitals.

[0016] Figure 1 is a schematic diagram of an industrial robot equipped with the gripper 10 according to the first embodiment of the present invention. The gripper 10 is attached to the tip of the arm A of the robot and used. The specific form and configuration of the robot arm are not particularly limited. The arm A may be a multi-joint type or a parallel movement type arm.

[0017] Figure 2 is a diagram showing the configuration of the gripper 10 according to the first embodiment. The gripper 10 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.

[0018] The gripper 10 has a drive unit 19 and claw bases 18, 18. The claw bases 18, 18 perform an opening and closing movement by a power device (such as a motor or a pressure cylinder, etc.) and a mechanism (such as a speed reduction mechanism, a link, a cam, etc.) provided in the drive unit 19, and open and close the claw members 11, 11 and the grip members 12, 12 described later. For example, in the present embodiment, an electric motor and a ball screw are combined, and the drive unit 19 is configured such that the claw bases 18, 18 open and close in parallel. Note that the specific configuration and mechanism of the drive unit 19 and the claw bases 18 are not particularly limited, and 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 replace the claw members 11 and the grip members 12 in the gripper 10.

[0019] The gripper 10 has claw members 11, 11 and a grip member 12. The claw member 11 is provided so as to be openable and closable so that the gripper 10 grips the gripping object 99. In the present embodiment, the claw member 11 is attached to the claw base 18 by a screw or the like and is made openable and closable. The grip member 12 is attached to the claw member 11 and performs an opening and closing operation together with the claw member. Also, when gripping the gripping object 99, the grip member 12 comes into direct contact with the gripping object 99.

[0020] The direction in which the claw member 11 and the grip member 12 move along with the gripping operation of the gripper 10 is hereinafter referred to as the "gripping direction". In FIG. 2, the gripping direction is the horizontal direction in the figure. Also, in the gripper of the present embodiment, two claw members 11 and two grip members 12 are provided so as to be paired with each other. As a result, the object to be gripped placed between the grip members is gripped between the grip members 12, 12 as the interval between the claw members 11, 11 narrows. The number of the claw members 11 and the grip members 12 is not limited to two, and may be one or three or more.

[0021] The configurations of the claw member 11 and the grip member 12 in the gripper 10 will be described in more detail below. FIG. 3 is a cross-sectional view showing the structures of the claw member 11 and the grip member 12 in the gripper 10 of the first embodiment. The upper left figure in FIG. 3 is a cross-sectional view from the viewpoint corresponding to the left claw member 11 and the grip member 12 in FIG. 2. In the upper left figure in FIG. 3 and the lower left figure in FIG. 3 (X-X cross-sectional view), the gripping direction is the horizontal direction in the figure, and in the upper right figure in FIG. 3 (Y-Y cross-sectional view), the gripping direction is the depth direction of the paper surface.

[0022] The claw member 11 is formed of a material harder than the grip member, such as metal or plastic, so that the opening and closing movement of the claw base 18 given by the drive unit 19 is well transmitted to the grip member 12. That is, the claw member 11 has higher rigidity than the grip member so as not to substantially deform during the gripping operation. When the gripper 10 performs gripping, it is preferable that the grip member 12 is sandwiched between the claw member 11 and the object to be gripped 99, and the claw member 11 is configured to push the object to be gripped 99 via the grip member 12.

[0023] The grip member 12 is more flexible than the claw member 11, and when the gripper 10 grips the object to be gripped 99, the object to be gripped 99 is gripped while the grip member 12 deforms. Also, although not essential, the gripper 10 may be provided with another grip member (not shown) in addition to the grip member 12.

[0024] The grip member 12 includes an elastic member 131. The elastic member 131 is made of rubber or elastomer. Also, the grip member 12 includes an outer skin member 120. The outer skin member 120 is made of rubber or elastomer.

[0025] The outer skin member 120 is a box-shaped hollow structure member including a grip layer 121 and side walls 122, 123. And the elastic member 131 is disposed inside the outer skin member 120 (the hollow part of the hollow structure) so as to be wrapped by the outer skin member 120.

[0026] Although not essential, the outer skin member 120 of the grip member 12 in the present embodiment may be integrally formed in a box-shaped hollow shape having a flat plate-shaped wall (hereinafter also referred to as "grip wall") serving as the grip layer 121 and side walls 122, 123. When an object to be gripped is gripped by the grip member 12, the grip layer 121 is positioned between the elastic member 131 and the object to be gripped 99. In other words, the grip member 12 is configured such that the grip layer 121 and the elastic member 131 are arranged in order from the side of the object to be gripped (99).

[0027] The grip layer 121 is provided so as to contact the object to be gripped. The outer surface of the grip layer 121 is hereinafter referred to as a grip surface 12S. The grip layer 121 is a layer formed in a flat plate shape. Preferably, the grip layer 121 is made of rubber or elastomer having a durometer A hardness of 30 to 80 HDA in accordance with JIS-K6253. The specific resin material constituting the grip layer 121 may be rubber or thermosetting resin such as silicone rubber, acrylonitrile-butadiene rubber, urethane rubber, etc., or may be thermoplastic elastomer such as olefin-based thermoplastic elastomer or styrene-based thermoplastic elastomer. Various additives, fillers, etc. may be blended with these materials as necessary.

[0028] Here, the side walls 122, 123 of the outer skin member 120 are wall portions that extend along the opening and closing direction (grasping direction) of the grasping operation, and the side walls 122, 123 extend in a direction opposite to the object to be grasped 99 with respect to the grasping wall (121). The side walls 122, 123 that extend along the grasping direction are preferably provided in a flat plate shape or a cylindrical shape.

[0029] The flat plate-shaped grasping layer 121 does not necessarily have to be a perfect flat plate. Even if it is a grasping layer with a slightly bulging or dented curved surface or spherical surface, as long as it is generally flat, it is included in the flat plate-shaped grasping layer. Further, on the grasping surface 12S where the grasping layer 121 contacts the object to be grasped 99, in order to adjust the frictional force and surface adhesiveness, protrusions, holes, ridges, grooves, checkering, dot patterns, and textures such as satin finish, wrinkles, and embossing may be provided. On the grasping surface 12S side of the grasping layer 121, granular materials such as silica particles or rubber particles may be kneaded into the resin so that the granular materials are exposed on the grasping surface 12S.

[0030] Here, the elastic member 131 has flexibility that can be elastically deformed when grasping the object to be grasped 99. The elastomer constituting the elastic member 131 may be a thermoplastic elastomer. Although not limited, the hardness of the rubber or elastomer constituting the elastic member 131 is preferably about 50 to 85 degrees in Shore A hardness.

[0031] The elastic member 131 is plate-shaped. Also, although not essential, in this embodiment, the elastic member 131 has a flat plate-shaped base portion 132 and a plurality of protrusions 133, 133. Although not essential, in this embodiment, the protrusions 133, 133 are formed to protrude on the base portion 132 so as to be scattered at a predetermined interval. In this embodiment, the protrusions 133, 133 are provided in an orthogonal lattice pattern. 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 side of the claw member 11 and the tip side (one end) 131a of the protruding protrusion 133 is located on the side of the object to be grasped (99).

[0032] The protrusions 133, 133 may have a solid shape, such as a cylindrical shape, a prismatic shape, or a solid hemispherical shape. Preferably, as in the present embodiment, the protrusions 133, 133 are hollow protrusions having a hollow portion inside the protrusions. In the present embodiment, the protrusions 133, 133 have a portion that rises cylindrically from the base 132 and a portion that serves as a lid of the cylinder. The specific form of the hollow protrusion may be other forms as described later.

[0033] Although not essential, in the present embodiment, the elastic member 131 is configured to be integrally formed in a single sheet shape in which the base 132 and the hollow protrusion 133 are continuous. That is, a hole is formed in the base 132 at the portion where the hollow protrusion 133 is provided, and air can flow between the hollow portion of the hollow protrusion 133 and the outside through such a hole. The elastic member 131 in such a form can be formed by injection molding, vacuum molding, press molding, etc., and is rich in flexibility.

[0034] Also, although not essential, in the present embodiment, the elastic member 131 is provided so that the tip 131a of the protrusion 133 abuts on the gripping layer 121. Although not essential, the elastic member 131 may be adhered to the gripping layer 121. Further, the elastic member 131 may be adhered, welded, or integrally formed with the gripping layer 121.

[0035] When the elastic member 131 is arranged to be wrapped by the outer skin member 120, the elastic member 131 is arranged behind the gripping layer 121 while abutting on the gripping layer 121, and the tip 131a of the hollow protrusion of the elastic member 131 and the portion where the elastic member 131 contacts the gripping layer 121 and the portion where the elastic member 131 does not contact the gripping layer 121 are distributed in an island shape when viewed along the gripping direction. In the non-contact portion, a gap portion 124 is formed between the elastic member 131 and the gripping layer 121. The gripping layer 121 itself can be deformed flexibly in the gripping direction, but at the portion where the gripping layer 121 contacts the elastic member 131, the gripping layer 121 is supported by the elastic member 131, and the deformation in the gripping direction is restricted. Such a combination of the island structure and the gripping layer contributes to enhancing the flexibility and holding force of the grip member 12.

[0036] In the gripper 10, the claw members 11 have rising surfaces 111, 111 that extend along the gripping direction. The shape of the claw member 11 is shown in FIG. 4. Although not essential, in the claw member 11 of this embodiment, the portion where the grip member 12 is attached is a recessed portion that is cuboid-shaped, and rising surfaces 111, 111 that extend along the gripping direction are provided so as to surround the attachment surface 11S to which the grip member 12 is attached.

[0037] Although not essential, preferably, as in this embodiment, the rising surfaces 111, 111 are provided in pairs so as to face each other in the width direction (the left-right direction in the upper-right diagram of FIG. 4) or the length direction (the left-right direction in the upper-right diagram of FIG. 4) of the claw member.

[0038] In the gripper 10, as shown in FIG. 3, the rising surfaces 111, 111 of the claw member 11 and the side walls 122, 123 of the outer skin member are provided so as to face each other. When the object 99 to be gripped is gripped, the outer skin member 120 deforms. At this time, the contact between the rising surface 111 and the side wall 122 (123) restricts the movement of the gripping layer 121 (movement in a direction orthogonal to the gripping direction: movement in the width direction or length direction of the claw member).

[0039] Although not essential, preferably, so that the movement of the gripping layer 121 is effectively restricted by the contact between the rising surface 111 and the side walls 122 (123), the rising surface 111 and the side walls 122, 123 are in contact with each other when the gripper 10 has not yet gripped the object 99. Also, although not essential, preferably, in the length direction of the claw member 11, the rising surfaces 111, 111 are provided on the claw member 11 with respect to the side walls 123, 123 located on both sides of the grip member, respectively. Also, although not essential, preferably, in the width direction of the claw member 11, the rising surfaces 111, 111 are provided on the claw member 11 with respect to the side walls 122, 122 located on both sides of the grip member, respectively. Further, although not essential, preferably, the opposing rising surfaces 111 and the side walls 122(123) may be substantially parallel to each other. Also, a gap with a substantially constant width may be provided between the opposing rising surfaces 111 and the side walls 122(123). Further, preferably, the rising surfaces 111, 111 and the side walls 122, 123 of the outer skin member are not adhered / jointed to each other. Thereby, the grip member becomes more flexible.

[0040] The method and means for assembling the grip member 12 and integrating (attaching) it with the claw member 11 are not particularly limited. For example, the base 132 of the elastic member 131 may be attached to the attachment surface 11S of the claw member 11, the outer skin member 120 may be arranged so as to cover the elastic member 131, and the end edges of the side walls 122, 123 of the outer skin member may be adhered to the attachment surface 11S of the claw member 11 to attach the grip member 12 to the claw member 11. If necessary for preventing detachment, etc., the space between the outer skin member 120 and the elastic member 131 and the claw member 11 may be screwed, or the two may be fixed with an adhesive, an adhesive agent, an adhesive tape, etc.

[0041] A manufacturing method of members and the like for constituting the gripper 10 will be described. Regarding the drive unit 19, the claw base 18, the claw member 11, etc., they can be manufactured in the same manner as the members of a conventionally known industrial robot. Regarding the gripping layer 121 (outer skin member 120) of the grip member 12, it can be manufactured by injection molding or casting molding of a rubber material or a thermoplastic elastomer material. Also, regarding the elastic member 131 of the grip member 12, it can be manufactured by injection molding a rubber material or a thermoplastic elastomer material, or by press molding a sheet material of a rubber material or a thermoplastic elastomer material. The elastic member 131 may be arranged inside the outer skin member 120, and these may be integrated as the grip member 12 with the claw member 11.

[0042] The operation and effects of the gripper 10 of the above first embodiment will be described. According to the gripper 10 of the above embodiment, while gripping the object to be gripped flexibly, the position and posture of the object to be gripped can be controlled more accurately.

[0043] In the gripper 10 of the above-described embodiment, the grip member 12 includes a plate-shaped elastic member 131 made of rubber or an elastomer and an outer skin member 120 made of rubber or an elastomer. The outer skin member 120 is formed in a box-shaped hollow shape so as to include a grip layer 121 positioned between the elastic member 131 and the object 99 to be gripped, and side walls 122 and 123 extending in the gripping direction. The elastic member 131 is disposed so as to be wrapped by the outer skin member 120. Therefore, following the shape of the object 99 to be gripped, the outer skin member 120 and the elastic member 131 are flexibly deformed, and the gripping by the grip member 12 is performed. Accordingly, the object 99 to be gripped can be flexibly gripped.

[0044] Next, the accurate control of the position and posture of the object to be gripped will be described. FIG. 6 is a view showing a gripping state of a gripper of the prior art, that is, a gripper having no rising surfaces 111 and 111 in the gripper 10 of the above-described embodiment. The gripper of FIG. 6 has an outer skin member 820 and an elastic member 831 configured in the same manner as the gripper 10 of the above-described embodiment, and can flexibly grip the object 99 to be gripped.

[0045] On the other hand, in the gripper of FIG. 6, since the outer skin member 820 and the elastic member 831 are flexibly deformed, a situation lacking accuracy occurs in controlling the position and posture of the object 99 to be gripped. For example, in the example of FIG. 6, the outer skin member 820 and the elastic member 831 may be deformed so as to fall downward in the figure. With such a deformation, when the object 99 to be gripped is firmly gripped by the gripper, the relative position and relative posture between the object 99 to be gripped and the claw member 81 change, making it difficult to accurately control the position and posture of the object 99 to be gripped.

[0046] According to the gripper 10 of the first embodiment, the claw member 11 has rising surfaces 111 and 111 extending along the gripping direction, and the rising surfaces 111 and 111 of the claw member 11 and the side walls 122 and 123 of the outer skin member 120 face each other, and the movement of the grip layer 121 is restricted by the contact between the rising surface 111 and the side wall 122 (123).

[0047] Therefore, when gripping is performed with the gripper 10 of the first embodiment, as shown in FIG. 5, it is possible to suppress or prevent the outer skin member 120 from being deformed so as to fall upward or downward in FIG. 5. Therefore, according to the gripper 10 of the first embodiment, since the rising surface 111 and the side walls 122, 123 of the outer skin member are arranged to face each other, the gripping layer 121 in contact with the object to be gripped 99 moves in a direction orthogonal to the gripping direction (for example, the vertical direction in FIG. 5 or the depth direction of the paper surface in FIG. 5). That is suppressed or prevented. That is, according to the gripper 10 of the above embodiment, the position and posture of the object to be gripped 99 can be controlled more accurately.

[0048] Also, although not essential, when the rising surface 111 and the side wall 122 (123) are in contact with each other like the gripper 10 of the first embodiment, the position and posture of the object to be gripped 99 can be more effectively and accurately controlled. This is because the movement of the gripping layer 121 in the direction in which the rising surface 111 is provided is more surely suppressed or prevented.

[0049] Also, although not essential, when the rising surfaces 111, 111 are provided on the claw member 11 with respect to the side walls (for example, 122, 122) located on both sides of the grip member 12 in the length direction or the width direction of the claw member 11 like the gripper 10 of the first embodiment, the position and posture of the object to be gripped 99 can be particularly effectively and accurately controlled. When viewed along the gripping direction, the gripping layer 121 is sandwiched between the rising surfaces 111, 111, and the movement of the gripping layer 121 in the direction in which the rising surface 111 is provided is more surely suppressed or prevented.

[0050] From the viewpoint of enhancing the accuracy of gripping, it is particularly preferable that the rising surfaces 111, 111 are provided so as to surround the grip member 12 over the entire circumference when viewed along the gripping direction, like the gripper 10 of the first embodiment.

[0051] Further, although not essential, like the gripper 10 of the above embodiment, the elastic member 131 has a flat base portion 132 and a plurality of protrusions 133, 133, and the protrusions 133, 133 are formed to protrude so as to be scattered on the base portion 132. When this is the case, the contact between the gripping layer 121 and the elastic member 131 becomes island-like, facilitating the flexible deformation of the gripping layer 121 while increasing the holding force for holding the object to be gripped. The holding force refers to the reaction force that resists the movement when attempting to move the gripped object along the gripping surface. When the contact is island-like, the protruding portion of the object to be gripped enters the gaps or voids between the protrusions 133, 133 of the elastic member, causing the gripping layer 121 to deform flexibly so that the object to be gripped is easily gripped and the holding force increases.

[0052] The invention is not limited to the above embodiment and can be implemented with various modifications. Other embodiments of the invention will be described below. In the following description, the focus will be on the parts that are different from the above embodiment, and the detailed description of the same parts will be omitted. Also, these embodiments can be implemented by combining some of them with each other or by replacing some of them.

[0053] FIG. 7 is a diagram showing a modified example (claw member 41) of a claw member that can be used for the gripper of the above embodiment. In the modified example claw member 41, a rising surface 411 is provided only on the tip side of the claw member 41 rather than on the mounting surface 41S for mounting the grip member (12).

[0054] Even with such a claw member, if the gripper is configured by attaching the grip member (12) such that the rising surface 411 of the claw member 41 and the side wall (123) of the outer skin member (120) face each other, the movement of the gripping layer (121) is restricted by the contact between the rising surface 411 and the side wall (123). Also in this embodiment, at least the movement of the gripping layer (121) in the direction toward the tip of the claw member 41 is restricted. Therefore, even with the gripper using the claw member 41, the accuracy of the gripping control position and posture can be improved.

[0055] FIG. 8 is a view showing another modification example (claw member 51) of the claw member that can be used for the gripper of the above-described embodiment. In the claw member 51 of the modification example, a pair of rising surfaces 511 and 511 are provided so as to face each other in the width direction of the mounting surface 51S for mounting the grip member (12).

[0056] Even with such a claw member, if the grip member (12) is attached to the mounting surface 51S so that the rising surfaces 511 and 511 of the claw member 51 and the side walls (122 and 122) of the outer skin member (120) face each other, respectively, to form a gripper, the movement of the gripping layer (121) is restricted by the contact between the rising surfaces 511 and 511 and the side walls (122 and 122). Therefore, even with the gripper using the claw member 51, the accuracy of the position and posture of the gripping control can be improved. Further, in this way, if the rising surfaces 511 and 511 are provided on the claw member with respect to the side walls (122 and 122) located on both sides of the grip member in the width direction, respectively, the accuracy of the position control in the width direction can be particularly improved.

[0057] FIG. 9 is a view showing still another modification example (claw member 61) of the claw member that can be used for the gripper of the above-described embodiment. In the claw member 61 of the modification example, the arrangement of the mounting surface 61S and the rising surfaces 611 and 611 is the same as that of the claw member 11 in the first embodiment. On the other hand, in the claw member 61 of the modification example, a portion (a frame-shaped portion surrounding the mounting surface 61S) 61B where the rising surfaces 611 and 611 are provided is formed of a material different from that of the main body portion 61A of the claw member. For example, the claw member 61 may be configured such that the main body portion 61A is made of aluminum and the frame-shaped portion 61B is made of hard rubber or plastic.

[0058] Thus, even if the claw member 61 is composed of a plurality of materials, by attaching the grip member (12) to the claw member 61 such that the rising surfaces 611, 611 of the claw member 61 and the side walls (122, 123) of the outer skin member (120) face each other, the movement of the gripping layer (121) is restricted by the contact between the rising surfaces 611, 611 and the side walls (122, 123). Therefore, even with the gripper using the claw member 61, the accuracy of gripping position control and posture control can be enhanced.

[0059] When the claw member 61 is composed of a plurality of materials, from the viewpoint of enhancing the accuracy of the position and posture of gripping control, it is preferable that the material constituting the portions of the rising surfaces 611, 611 be a harder material than the outer skin member (120).

[0060] FIG. 10 shows a cross-sectional view of the structure of the claw member and the grip member of the gripper according to the second embodiment. As shown in FIG. 10, the outer skin member 120 may be arranged so as to wrap both the claw member 11 and the elastic member 131. Such a structure is a structure that can simplify the attachment of the outer skin member 120 to the claw member 11. Note that the means and structure for fixing the outer skin member 120 and the side walls 122, 122 to the claw member 11 may be by means such as adhesion, welding, use of an adhesive, screw fastening, pinning, formation of a flange portion and pressing of the flange portion, or other mechanical fixing methods.

[0061] In the gripper of the first embodiment shown in FIG. 3, the rising surfaces 111, 111 of the claw members 11 are provided so as to face the outside of the side walls 122, 122 of the outer skin member 120 and to protrude from the main body portion of the claw members toward the gripping surface. However, in the gripper of the second embodiment shown in FIG. 10, the rising surfaces 111, 111 of the claw members 11 are provided so as to face the inside of the side walls 122, 122 of the outer skin member 120 and to protrude from the main body portion of the claw members toward the gripping surface. Even in such a configuration, the movement of the gripping layer 121 (vertical movement in the X-X cross section of FIG. 10) is restricted by the contact between the rising surfaces 111, 111 and the side walls 122, 122. Similarly, the effect of being able to more accurately control the position and posture of the object to be gripped while softly gripping the object to be gripped is achieved.

[0062] As the elastic member used in the gripper 10 of the above embodiment, a member having a predetermined flexibility can be appropriately used. The elastic member may be a flat elastic member (for example, a rubber sheet) made of a foamed resin or a foamed rubber. Further, the elastic member may be a hollow elastic member filled with a gas or a liquid. Preferably, the elastic member has a shape having a gap 124 between the gripping layer (121) and the side walls (122, 123), which contributes to enhancing the flexibility of the grip member (12). Further, when the elastic member has protrusions, the specific shape and arrangement of the protrusions can be changed. For example, the elastic member may be one in which two-stage stepped columnar protrusions are scattered.

[0063] The shape and properties of the object to be gripped by the gripper are not particularly limited as long as the gripping operation is possible. Since the grip member in the gripper of the above embodiment is highly flexible, it is possible to grip objects of various shapes, such as a rectangular parallelepiped, a cylinder, a pyramid, a polyhedron, a sphere, and an ellipsoid, in various postures.

Industrial Applicability

[0064] The gripper is attached to the tip of a robot arm and can be used, for example, in a conveying operation, and has high industrial utility value.

Description of Symbols

[0065] A robot arm 10 Gripper 11 Claw member 111 Rising surface 12 Gripping member 120 Outer skin member 121 Holding layer 122, 123 Side walls 131 Elastic member 132 Base 133 Protrusion 99 Object to be gripped

Claims

1. A gripper having a claw member provided to be openable and closable so as to grip 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 to be gripped, wherein the claw member has a higher rigidity than the grip member so as not to substantially deform during the gripping operation, the grip member includes a plate-shaped elastic member made of rubber or elastomer, the grip member further includes an outer skin member made of rubber or elastomer, the outer skin member is formed in a box-shaped hollow shape so as to include a gripping layer positioned between the elastic member and the object to be gripped and side walls extending in the gripping direction, the elastic member is disposed so as to be wrapped by the outer skin member, the claw member has a mounting recess for the grip member and a rising surface extending along the gripping direction, the rising surface of the claw member and the side wall of the outer skin member face each other, the movement of the gripping layer is restricted by the contact between the rising surface and the side wall, a gripper.

2. The gripper according to claim 1, wherein the rising surface and the side wall are in contact with each other.

3. The gripper according to claim 1, wherein the rising surface is provided on the claw member with respect to the side walls located on both sides of the grip member in the length direction or width direction of the claw member.

4. The gripper according to any one of claims 1 to 3, wherein the elastic member has a flat base portion and a plurality of protrusions, and the protrusions are formed to protrude so as to be scattered on the base portion.

5. The gripper according to any one of claims 1 to 4, wherein the outer skin member has a plurality of grooves on an inner surface thereof, and the grooves extend in a direction intersecting the gripping direction.

6. The gripper according to any one of claims 1 to 5, wherein the outer skin member has a plurality of ribs on an inner surface thereof, and the ribs extend in a direction intersecting the gripping direction.

7. The gripper according to any one of claims 1 to 6, wherein the outer skin member has a plurality of projections on an inner surface thereof, and the projections extend in a direction intersecting the gripping direction.

Images