Gripper

Abstract

To more accurately control a position and an attitude of a gripping object while flexibly gripping the gripping object.SOLUTION: The gripper 10 includes a claw member 11 provided so as to be openable and closable, and a grip member 12 attached to the claw member 11. The claw member 11 has rigidity higher than that of the grip member 12 so as not to be substantially deformed 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-like hollow shape so as to include a grip layer 121 and a side wall 122,123. The elastic member 131 is disposed 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 are opposed to each other, and the movement of the holding layer 121 is restricted by the contact of the rising surface 111 and the side wall 122.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a gripper used in an industrial robot or the like, and more particularly to a gripper that grips a work object by opening and closing operations. [Background technology]

[0002] In recent years, industrial robots have been used for a variety of purposes, such as transporting and assembling components. Industrial robots for material handling, which transport work objects, have also been put to practical use. When an industrial robot transports a work object, 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. Different grippers are used depending on the nature and shape of the work object. Grippers include those that use suction forces such as magnetic force or vacuum pulling, and those that grasp the work object by opening and closing.

[0003] Grippers that grip workpieces by opening and closing are known, for example, from those disclosed in Patent Document 1 and Patent Document 2. In the gripper of Patent Document 1, a leaf spring and a cushioning material are opened and closed by an actuator. It is disclosed that this gripper can grip and transport objects with fragile mechanical properties.

[0004] Furthermore, the gripper in Patent Document 2 utilizes an elastic member that has an elastic member with a hollow protrusion of a specific shape, and it is disclosed that this gripper has a high holding force while flexibly gripping the object to be gripped. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 07-276281 [Patent Document 2] Japanese Patent Application Publication No. 2023-093789 Summary of the Invention [Problem to be solved by the invention]

[0006] The gripper in Patent Document 1 uses a 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, but on the other hand, the holding force during gripping simply depends on the friction force between the cushioning material and the object to be gripped. As a result, the holding force is weak in a direction intersecting the gripping direction, which causes problems such as the object to fall or the position or posture of the gripped object changing easily.

[0007] Furthermore, the gripper in Patent Document 2 can flexibly grip an object to be gripped while increasing the holding force. However, even with the gripper in Patent Document 2, there is a demand for more accurate control of the position and orientation 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 can more accurately control the position and orientation of the object to be gripped. [Means for solving the problem]

[0009] As a result of extensive research, the inventors have found that the above-mentioned problems can be solved by configuring a gripper having a claw member and a gripping member, in which the gripping member includes an elastic member made of rubber or elastomer and an outer cover member made of rubber or elastomer, the gripping member being arranged so that the elastic member is wrapped in the outer cover member, and further, the gripper is configured so that the side walls of the outer cover member face the raised surfaces provided on the claw members, and the raised surfaces come into contact with the side walls, thereby restricting movement of the gripping layer of the outer cover member, and have completed the present invention.

[0010] The present invention provides a gripper having claw members that can be opened and closed to grip an object to be gripped, and grip members attached to the claw members so as to come into contact with the object to be gripped when gripping the object, wherein the claw members have higher rigidity than the grip members so as not to substantially deform during the gripping operation, the grip members include a plate-shaped elastic member made of rubber or elastomer, and the grip members further include an outer cover member made of rubber or elastomer, the outer cover member being formed in a box-like hollow shape so as to include a gripping layer located between the elastic member and the object to be gripped, and side walls extending in the gripping direction, the elastic members being arranged to be enclosed by the outer cover member, the claw members having raised surfaces extending along the gripping direction, the raised surfaces of the claw members and the side walls of the outer cover member facing each other, and movement of the gripping layer being restricted by contact between the raised surfaces and the side walls (first invention).

[0011] In the first invention, preferably, the raised surface and the side wall are in contact with each other (invention 2). Also, in the first invention, preferably, the raised surface is provided on the claw member for each of the side walls located on both sides of the grip member in the length direction or width direction of the claw member (invention 3). Also, in any of the first to third inventions, preferably, the elastic member has a flat base and a plurality of protrusions, and the protrusions are formed to protrude so as to be scattered on the base (invention 4). [Effects of the Invention]

[0012] According to the gripper of the present invention (first invention), it is possible to flexibly grip an object to be gripped, and also to more accurately control the position and orientation of the object to be gripped.

[0013] Furthermore, in the second and third aspects of the invention, the position and orientation of the object to be grasped can be controlled more accurately, and in the fourth aspect of the invention, the holding force can be increased while the position and orientation of the object to be grasped can be controlled accurately. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram of an industrial robot equipped with a gripper according to the present invention. [Figure 2] 1A and 1B are diagrams illustrating a configuration of a gripper according to the present invention. [Figure 3] 3 is a cross-sectional view showing the structure of the claw members and grip members of the gripper of the first embodiment. FIG. [Figure 4] 3A and 3B are diagrams illustrating the shape of a claw member of a gripper according to the first embodiment. [Figure 5] 3A and 3B are diagrams illustrating a situation in which an object to be grasped is grasped by the gripper of the first embodiment. [Figure 6] FIG. 1 is a diagram showing a situation in which an object to be grasped is grasped by a gripper of the prior art. [Figure 7] 10A and 10B are diagrams showing modified examples of the claw members of the gripper; [Figure 8] 10A and 10B are diagrams showing other modified examples of the claw members of the gripper. [Figure 9] 10A and 10B are diagrams showing still another modified example of the claw members of the gripper. [Figure 10] 10A and 10B are cross-sectional views showing the structure of the claw members and grip members of a gripper according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, with reference to the drawings, an embodiment of the invention will be described using a gripper attached to an industrial robot as an example. Note that the invention is not limited to the individual embodiments shown below, and can be implemented by modifying the form. For example, the gripper of the present invention can be used not only in industrial robots used in the manufacturing and distribution industries (e.g., assembly robots, transport robots, collaborative robots), but also in robots used in homes, hospitals, etc. (e.g., assistance robots, assistive robots, nursing robots, prosthetic limbs, etc.).

[0016] FIG. 1 is a schematic diagram of an industrial robot equipped with a gripper 10 according to a first embodiment of the present invention. The gripper 10 is attached to the tip of an arm A of the robot when in use. The specific type and form of the robot arm are not particularly limited. The arm A may be of an articulated type or a parallel moving type.

[0017] 2 is a diagram showing the configuration of the gripper 10 of the first embodiment. The gripper 10 can grip a gripping object 99 (also referred to as a work object) by opening and closing, 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. The drive unit 19 is provided with a power device (e.g., a motor, a pressure cylinder, etc.) and a mechanism (e.g., a speed reducer, a link, a cam, etc.) that cause the claw bases 18 to open and close, thereby opening and closing the claw members 11 and the grip members 12, which will be described later. For example, in this embodiment, the drive unit 19 is configured by combining an electric motor and a ball screw so that the claw bases 18 open and close in parallel. Note that the specific configurations and mechanisms of the drive unit 19 and the claw bases 18 are not particularly limited, and they may open and close the claw members and the grip members in parallel, or may open and close in a compass-like manner. Furthermore, the claw bases 18 are not essential, and the drive unit 19 may directly open and close the claw members 11, which will be described later. The presence of the claw bases 18 is convenient because it makes it easier to replace the claw members 11 and the grip members 12 in the gripper 10.

[0019] The gripper 10 has claw members 11 and a grip member 12. The claw member 11 is provided so as to be openable and closable so that the gripper 10 can grip a gripping object 99. In this embodiment, the claw member 11 is attached to a claw base 18 by a screw or the like, so as to be openable and closable. The grip member 12 is attached to the claw member 11, and opens and closes together with the claw member. Furthermore, 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 members 11 and the grip members 12 move in association with the gripping operation of the gripper 10 will be referred to hereinafter as the “gripping direction.” In Fig. 2, the gripping direction is the left-right direction of the drawing. Furthermore, the gripper of this embodiment is provided with two pairs of claw members 11 and two pairs of grip members 12. As a result, an object to be gripped placed between the grip members is gripped between the grip members 12 as the gap between the claw members 11 narrows. The number of claw members 11 and grip members 12 is not limited to two, and may be one, or three or more.

[0021] The configuration of the claw members 11 and the gripping members 12 of the gripper 10 will be described in more detail below. Fig. 3 is a cross-sectional view showing the structure of the claw member 11 and the grip member 12 in the gripper 10 of the first embodiment. The drawing in the upper left of Fig. 3 is a cross-sectional view taken from a viewpoint corresponding to the claw member 11 and the grip member 12 on the left side in Fig. 2. In the drawing in the upper left of Fig. 3 and the drawing in the lower left of Fig. 3 (XX cross-sectional view), the gripping direction is the left-right direction of the drawing, and in the drawing in the upper right of Fig. 3 (YY cross-sectional view), the gripping direction is the depth direction of the paper.

[0022] The claw members 11 are formed of a material harder than the grip members, such as metal or plastic, so that the opening and closing movement of the claw bases 18 provided by the drive unit 19 is efficiently transmitted to the grip members 12. In other words, the claw members 11 have higher rigidity than the grip members so that they do not substantially deform during the gripping operation. It is preferable that the claw members 11 are configured so that, when gripping is performed by the gripper 10, the grip members 12 are sandwiched between the claw members 11 and the object to be gripped 99, and the claw members 11 push the object to be gripped 99 via the grip members 12.

[0023] The gripping members 12 are more flexible than the claw members 11, and when the gripper 10 grips the object 99, the gripping members 12 deform to grip the object 99. Furthermore, although not essential, the gripper 10 may be provided with another gripping member (not shown) in addition to the gripping member 12.

[0024] The grip member 12 includes an elastic member 131. The elastic member 131 is made of rubber or elastomer. The grip member 12 also includes an outer cover member 120. The outer cover member 120 is made of rubber or elastomer.

[0025] The outer cover member 120 is a box-shaped member with a hollow structure that includes a gripping layer 121 and side walls 122 and 123. The elastic member 131 is disposed inside the outer cover member 120 (in the hollow portion of the hollow structure) so as to be enclosed by the outer cover member 120.

[0026] Although not required, the outer cover member 120 of the grip member 12 in this embodiment may be integrally molded into a box-like hollow shape having a flat wall (hereinafter also referred to as the "gripping wall") that forms the gripping layer 121 and side walls 122, 123. The grip member 12 is configured so that 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 layer 121 and the elastic member 131 are arranged in order from the side of the object to be gripped (99).

[0027] The gripping layer 121 is provided so as to come into contact with an object to be gripped. The outer surface of the gripping layer 121 is hereinafter referred to as a gripping surface 12S. The gripping layer 121 is a layer formed in a flat plate shape. Preferably, the gripping layer 121 is made of rubber or elastomer having a Duro A hardness of 30 to 80 HDA according to JIS-K6253. Specific resin materials constituting the gripping layer 121 may be rubbers such as silicone rubber, acrylonitrile butadiene rubber, or urethane rubber, or thermosetting resins, or thermoplastic elastomers such as olefin-based thermoplastic elastomers or styrene-based thermoplastic elastomers. These materials may contain various additives, fillers, etc., as needed.

[0028] Here, the side walls 122, 123 of the outer cover member 120 refer to wall portions extending along the opening and closing direction (gripping direction) of the gripping operation, and the side walls 122, 123 extend in the opposite direction to the gripping object 99 relative to the gripping wall (121). The side walls 122, 123 extending along the gripping direction are preferably provided in a flat or cylindrical shape.

[0029] The flat gripping layer 121 does not need to be a completely flat plate; even a gripping layer with a slightly curved or concave surface or a spherical surface is included in the flat gripping layer as long as it is generally flat. Furthermore, the gripping surface 12S where the gripping layer 121 comes into contact with the gripping object 99 may be provided with a background pattern such as protrusions, holes, ridges, grooves, checkering, dot patterns, matte finish, wrinkles, or grain to adjust the frictional force or surface adhesion. Granular material such as silica particles or rubber particles may be kneaded into the resin on the gripping surface 12S side of the gripping layer 121 so that the granular material is exposed on the gripping surface 12S.

[0030] Here, the elastic member 131 has flexibility that allows it to be elastically deformed when gripping the gripping object 99. The elastomer that forms the elastic member 131 may be a thermoplastic elastomer. Although not limited thereto, it is preferable that the hardness of the rubber or elastomer that forms the elastic member 131 is approximately 50 to 85 degrees in Duro A hardness.

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

[0032] The protrusions 133, 133 may be solid, for example, cylindrical, prismatic, or solid hemispherical, but preferably, as in this embodiment, the protrusions 133, 133 are hollow protrusions having a hollow portion inside the protrusion. In this embodiment, the protrusions 133, 133 have a cylindrical portion rising from the base 132 and a portion that serves as a lid for the cylinder. The specific shape of the hollow protrusion may be other shapes as described below.

[0033] Although not essential, in this embodiment, elastic member 131 is configured by integrally molding base 132 and hollow protrusions 133 into a single continuous sheet. That is, holes are formed in base 132 at the portions where hollow protrusions 133 are provided, and these holes allow air to flow between the hollow portions of hollow protrusions 133 and the outside. Elastic member 131 of this type can be molded by injection molding, vacuum molding, press molding, or the like, and is highly flexible.

[0034] Although not required, in this embodiment, the elastic member 131 is provided so that the tip 131a of the protrusion 133 abuts against the gripping layer 121. Although not required, the elastic member 131 may be adhered to the gripping layer 121. Furthermore, the elastic member 131 may be adhered to, welded to, or integrally formed with the gripping layer 121.

[0035] When the elastic member 131 is arranged so as to be wrapped in the outer cover member 120, the elastic member 131 is arranged behind the gripping layer 121 while abutting against the gripping layer 121, and the areas where the tips 131a of the hollow protrusions of the elastic member 131 come into contact with the gripping layer 121 and the areas where the elastic member 131 and the gripping layer 121 do not come into contact are distributed in an islands-in-a-sea pattern when viewed along the gripping direction. In the areas where they do not come into contact, gaps 124 are formed between the elastic member 131 and the gripping layer 121. The gripping layer 121 itself can flexibly deform in the gripping direction, but in the areas where it comes into contact with the elastic member 131, the gripping layer 121 is supported by the elastic member 131, limiting deformation in the gripping direction. The combination of this islands-in-a-sea structure and the gripping layer contributes to increasing the flexibility and holding power of the grip member 12.

[0036] In the gripper 10, the claw member 11 has raised surfaces 111, 111 extending along the gripping direction. Fig. 4 shows the shape of the claw member 11. Although not essential, in the claw member 11 of this embodiment, the portion to which the gripping member 12 is attached is a recessed rectangular parallelepiped, and raised surfaces 111, 111 extending along the gripping direction are provided so as to surround the attachment surface 11S to which the gripping member 12 is attached.

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

[0038] 3, in the gripper 10, the rising surfaces 111, 111 of the claw members 11 and the side walls 122, 123 of the outer cover member are arranged to face each other. When the object to be gripped 99 is gripped, the outer cover member 120 is deformed, and at that time, the contact between the rising surfaces 111 and the side walls 122 (123) restricts the movement of the gripping layer 121 (movement in a direction perpendicular to the gripping direction: movement in the width direction or length direction of the claw members).

[0039] Preferably, but not necessarily, the raised surface 111 and the side walls 122, 123 are in contact with each other when the gripper 10 is not yet gripping the object to be gripped 99, so that contact between the raised surface 111 and the side walls 122 (123) effectively restricts movement of the gripping layer 121. Preferably, but not necessarily, the raised surfaces 111 are provided on the claw members 11 for the side walls 123 located on both sides of the gripping member in the length direction of the claw members 11. Preferably, but not necessarily, the raised surfaces 111 are provided on the claw members 11 for the side walls 122 located on both sides of the gripping member in the width direction of the claw members 11. Preferably, but not necessarily, the opposing rising surface 111 and side wall 122 (123) may be substantially parallel. A gap of substantially constant width may be provided between the opposing rising surface 111 and side wall 122 (123). Preferably, the rising surfaces 111, 111 and the side walls 122, 123 of the outer cover member are not bonded / joined to each other. This makes the grip member more flexible.

[0040] There are no particular limitations on the method or means for assembling the grip member 12 and integrating (attaching) it to the claw member 11. For example, the grip member 12 may be attached to the claw member 11 by attaching the base 132 of the elastic member 131 to the attachment surface 11S of the claw member 11, arranging the outer cover member 120 so as to cover the elastic member 131, and bonding the distal edges of the side walls 122, 123 of the outer cover member to the attachment surface 11S of the claw member. If necessary to prevent detachment, the outer cover member 120 or the elastic member 131 may be screwed to the claw member 11, or they may be fixed together with an adhesive, a pressure-sensitive adhesive, adhesive tape, or the like.

[0041] A method for manufacturing the members for constituting the gripper 10 will be described. The drive unit 19, claw base 18, claw member 11, etc. can be manufactured in the same manner as components of conventionally known industrial robots. The gripping layer 121 (outer cover member 120) of the grip member 12 can be manufactured by injection molding, cast molding, or the like using a rubber material or a thermoplastic elastomer material. The elastic member 131 of the grip member 12 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 can be placed inside the outer cover member 120, and these can be integrated with the claw member 11 to form the grip member 12.

[0042] The effects of the gripper 10 of the first embodiment will be described. According to the gripper 10 of the above embodiment, it is possible to flexibly grip an object to be gripped, and also to more accurately control the position and orientation of the object to be gripped.

[0043] In the gripper 10 of the above embodiment, the gripping member 12 includes a plate-shaped elastic member 131 made of rubber or elastomer and an outer cover member 120 made of rubber or elastomer, and the outer cover member 120 is formed in a box-like hollow shape so as to include a gripping layer 121 located between the elastic member 131 and the object to be gripped 99 and side walls 122, 123 extending in the gripping direction, and the elastic member 131 is arranged so as to be wrapped in the outer cover member 120. Therefore, gripping by the gripping member 12 is performed while the outer cover member 120 and the elastic member 131 flexibly deform to follow the shape of the object to be gripped 99. Therefore, the object to be gripped 99 can be flexibly gripped.

[0044] Next, accurate control of the position and posture of the object to be grasped will be described. Fig. 6 is a diagram showing the gripping state of a conventional gripper, i.e., a gripper that does not have the raised surfaces 111, 111 of the gripper 10 of the above embodiment. The gripper of Fig. 6 has an outer cover member 820 and an elastic member 831 configured similarly to the gripper 10 of the above embodiment, and can flexibly grip the object to be gripped 99.

[0045] On the other hand, in the gripper of Fig. 6, because the outer cover member 820 and the elastic member 831 are flexibly deformed, there are cases where the gripper lacks accuracy in controlling the position and posture of the object to be grasped 99. For example, in the example of Fig. 6, the outer cover member 820 and the elastic member 831 may be deformed so as to fall downward in the figure, and if such deformation occurs, when the gripper firmly grasps the object to be grasped 99, the relative position and posture between the object to be grasped 99 and the claw members 81 change, making it difficult to accurately control the position and posture of the object to be grasped 99.

[0046] According to the gripper 10 of the first embodiment described above, the claw member 11 has raised surfaces 111, 111 extending along the gripping direction, and the raised surfaces 111, 111 of the claw member 11 and the side walls 122, 123 of the outer skin member 120 face each other, and contact between the raised surfaces 111 and the side walls 122 (123) restricts the movement of the gripping layer 121.

[0047] Therefore, when gripping is performed by the gripper 10 of the first embodiment, deformation of the outer cover member 120 so that it falls upward or downward in FIG. 5 is suppressed or prevented, as shown in FIG. 5. Therefore, according to the gripper 10 of the first embodiment, the rising surface 111 and the side walls 122, 123 of the outer cover member are arranged opposite to each other, so that the gripping layer 121 in contact with the gripping object 99 is suppressed or prevented from moving in a direction perpendicular to the gripping direction (for example, the vertical direction in FIG. 5 or the depth direction in FIG. 5). In other words, according to the gripper 10 of the embodiment, the position and posture of the gripping object 99 can be controlled more accurately.

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

[0049] Furthermore, although not essential, as in the gripper 10 of the first embodiment, if the claw members 11 are provided with raised surfaces 111, 111 on the side walls (e.g., 122, 122) located on both sides of the gripping member 12 in the length direction or width direction of the claw members 11, the position and posture of the object to be gripped 99 can be controlled accurately and particularly effectively. This is because, when viewed along the gripping direction, the gripping layer 121 is sandwiched between the raised surfaces 111, 111, and movement of the gripping layer 121 in the direction in which the raised surfaces 111 are provided is more reliably suppressed or prevented.

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

[0051] Furthermore, although not essential, as in the gripper 10 of the above embodiment, if the elastic member 131 has a flat base 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 132, the contact between the gripping layer 121 and the elastic member 131 will be in a sea-island shape, which will promote flexible deformation of the gripping layer 121 and increase the holding force for holding the object to be gripped. Note that the holding force is a reaction force that resists movement when the gripped object is moved along the gripping surface. When the contact is in a sea-island shape, the gripping layer 121 will flexibly deform so that the protruding portions of the object to be gripped enter the gaps and voids between the protrusions 133, 133 of the elastic member, making it easier to grip the object to be gripped and increasing the holding force.

[0052] The invention is not limited to the above-described embodiment, and various modifications can be made to the invention. Other embodiments of the invention will be described below, focusing on differences from the above-described embodiment, and detailed descriptions of similarities will be omitted. Furthermore, these embodiments can be implemented by combining parts of them with each other or by substituting parts of them.

[0053] 7 is a diagram showing a modified claw member (claw member 41) that can be used in the gripper of the above embodiment. In the modified claw member 41, a rising surface 411 is provided only on the tip side of the claw member 41 relative to the mounting surface 41S to which the grip member 12 is attached.

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

[0055] 8 is a diagram showing another modified claw member (claw member 51) that can be used in the gripper of the above embodiment. The modified claw member 51 is provided with a pair of raised surfaces 511, 511 that face each other in the width direction of the mounting surface 51S to which the grip member 12 is attached.

[0056] Even with such claw members, if a gripper is configured by attaching the gripping members (12) to the mounting surface 51S so that the rising surfaces 511, 511 of the claw members 51 face the side walls (122, 122) of the outer cover member (120), the movement of the gripping layer (121) is restricted by contact between the rising surfaces 511, 511 and the side walls (122, 122). Therefore, even with a gripper using the claw members 51, the accuracy of gripping position and posture can be improved. Furthermore, if the claw members are provided with rising surfaces 511, 511 for the side walls (122, 122) located on both sides of the gripping member in the width direction, the accuracy of position control in the width direction can be particularly improved.

[0057] 9 is a diagram showing yet another modified example of the claw member (claw member 61) that can be used in the gripper of the above embodiment. In the modified claw member 61, the arrangement of the mounting surface 61S and the raised surfaces 611, 611, etc. are the same as those of the claw member 11 in the above first embodiment. On the other hand, in the modified claw member 61, the portion 61B where the raised surfaces 611, 611 are provided (a frame-shaped portion surrounding the mounting surface 61S) is made 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 so that the main body portion 61A is made of aluminum and the frame-shaped portion 61B is made of hard rubber or plastic.

[0058] In this way, even if the claw members 61 are made of multiple materials, if the gripper is constructed by attaching the gripping members (12) to the claw members 61 so that the rising surfaces 611, 611 of the claw members 61 face the side walls (122, 123) of the outer cover member (120), the movement of the gripping layer (121) is limited by contact between the rising surfaces 611, 611 and the side walls (122, 123). Therefore, even with a gripper using the claw members 61, the accuracy of gripping position control and posture control can be improved.

[0059] When the claw member 61 is made of multiple materials, it is preferable that the material constituting the raised surfaces 611, 611 be harder than the outer cover member (120) in order to improve the accuracy of the position and posture of the gripping control.

[0060] Fig. 10 is a cross-sectional view showing the structure of the claw members and gripping members of the gripper according to the second embodiment. As shown in Fig. 10, the outer cover member 120 may be arranged so as to enclose both the claw members 11 and the elastic member 131. Such a structure allows the outer cover member 120 to be easily attached to the claw members 11. Note that the means or structure for fixing the outer cover member 120 or the side walls 122, 122 to the claw members 11 may be adhesive or welding, or may be a mechanical fixing method such as using an adhesive, screwing, pinning, forming a flange portion and pressing down the flange portion, or the like.

[0061] 3, the raised surfaces 111 of the claw members 11 are provided so as to face the outer sides of the side walls 122 of the outer cover member 120 and to protrude from the main body of the claw members in a direction toward the gripping surface, whereas in the gripper of the second embodiment shown in Fig. 10, the raised surfaces 111 of the claw members 11 are provided so as to face the inner sides of the side walls 122 of the outer cover member 120 and to protrude from the main body of the claw members in a direction toward the gripping surface. Even in this configuration, the movement of the gripping layer 121 (movement in the vertical direction in cross section XX in Fig. 10) is limited by contact between the raised surfaces 111 and the side walls 122, and similarly, an effect is achieved in that the gripping object can be flexibly gripped while the position and posture of the gripping object can be more accurately controlled.

[0062] The elastic member used in the gripper 10 of the above embodiment can be any member having a predetermined flexibility. The elastic member may be a flat elastic member (e.g., a rubber sheet) made of foamed resin or foamed rubber. The elastic member may also be a hollow elastic member filled with gas or liquid. Preferably, the elastic member has a shape that has a gap 124 between it and the gripping layer 121 or the side walls 122, 123, which contributes to increasing the flexibility of the gripping member 12. Furthermore, if the elastic member has protrusions, the specific shape and arrangement of the protrusions can be changed. For example, the elastic member may have two-tiered, columnar protrusions scattered thereon.

[0063] The shape and properties of the object to be gripped by the gripper are not particularly limited as long as they can be gripped. The gripping members of the grippers in the above embodiments are highly flexible, so they can grip objects of various shapes, such as rectangular parallelepipeds, cylinders, polygonal pyramids, polyhedrons, spheres, and ellipsoids, in a variety of positions. [Industrial Applicability]

[0064] The gripper can be attached to the tip of a robot arm and used for transporting work, for example, and is highly useful in industry. [Explanation of symbols]

[0065] A. Robot arm 10 Gripper 11 Claw member 111 Rising surface 12 Grip material 120 Outer skin 121 Grasping layer 122,123 side wall 131 Elastic member 132 Base 133 Protrusion 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 claw members have a higher rigidity than the grip members so as not to be substantially deformed during a gripping operation; the grip member includes a plate-shaped elastic member made of rubber or elastomer, the grip member further includes an outer cover member made of rubber or elastomer; the outer cover member is formed in a box-like hollow shape so as to include a gripping layer positioned between the elastic member and the object to be gripped, and a side wall extending in the gripping direction; The elastic member is disposed so as to be wrapped in the outer cover member, The claw member has a raised surface extending along the gripping direction, The raised surface of the claw member and the side wall of the outer cover member face each other, The movement of the gripping layer is restricted by contact between the raised surface and the side wall. Gripper.

2. The rising surface and the side wall are in contact with each other. The gripper of claim 1 .

3. The raised surfaces are provided on the claw members on the side walls located on both sides of the grip member in the length direction or width direction of the claw members, respectively. The gripper of claim 1 .

4. The elastic member has a flat base and a plurality of protrusions, The protrusions are formed so as to protrude from the base portion.

4. The gripper according to claim 1.

Images