Suction-attachment pad

Abstract

This suction-attachment pad, which suction-attaches an object and which is connected to a vacuum generator, comprises: a pad main body which includes a skirt portion that comes into contact with the object and that has an inclined surface, and a plurality of ribs that are formed at least in the radial direction inside the skirt portion; and a retaining portion which is disposed so as to cover the inclined surface of the skirt portion. When suction-attaching the object, the retaining portion comes into contact with the inclined surface further outward than an end portion, on the pad main body center side, of at least one of the plurality of ribs.

Description

suction pad

[0001] The present disclosure relates to suction pads.

[0002] A known workpiece suction device includes a flexible, dish-shaped suction pad, the peripheral edge of which is pressed against the surface of a workpiece, and when the sucked airspace within the suction pad, shielded by the surface of the workpiece, reaches a predetermined low-pressure state below atmospheric pressure, the workpiece is sucked to the suction pad. This workpiece suction device includes a pressing portion that presses the peripheral edge of the suction pad's flange, which is in close contact with the workpiece, from the back side of the suction pad toward the workpiece, and a hard cover body that is connected to a support member that supports the suction pad and is fixed to the back side of the suction pad, and when the sucked airspace reaches a predetermined low-pressure state below atmospheric pressure, the tight-contact edge of the flange is clamped between the workpiece and the pressing portion of the cover body (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2008-155309

[0004] The present disclosure provides a suction pad that can prevent the pad body from turning over even when the pad body has high flexibility that allows it to adsorb a bag.

[0005] One aspect of the present disclosure is a suction pad that adsorbs an object and is connected to a vacuum generator, the suction pad comprising: a pad body that contacts the object and has a skirt portion with a slope; and a plurality of ribs formed at least radially inside the skirt portion; and a retaining portion that is arranged to cover the slope of the skirt portion, wherein the retaining portion contacts the slope outside the end of at least one of the plurality of ribs that is closest to the center of the pad body when adsorbing the object.

[0006] According to the present disclosure, even when the pad body has high flexibility that allows it to adsorb a bag, the pad body can be prevented from turning over.

[0007] 11. A perspective view of a robot device having a suction pad according to embodiment 1 of the present disclosure in its suction hand. 12. A perspective view of the suction pad according to embodiment 1. 13. A cross-sectional side view of the suction pad when the pad body is at its natural length. 14. A cross-sectional side view of the suction pad when the pad body is contracted. 15. A cross-sectional side view of the suction pad according to a modified example in which the pressing part is not fixed to the stopper part. 16. A cross-sectional side view of the suction pad according to the modified example shown in FIG. 7. 17. A schematic diagram (1) illustrating the curling action of the skirt part. 18. A schematic diagram (2) illustrating the curling action of the skirt part. 19. A schematic diagram (3) illustrating the curling action of the skirt part. 20. A schematic diagram (4) illustrating the curling action of the skirt part. 21. An explanatory diagram showing the suction process when the target object is a bagged product. 22. An explanatory diagram showing the suction process when the surface to be suctioned is an inclined surface. 23. A perspective view of a suction pad not provided with a bellows tube. 24. A side view of the suction pad shown in FIG. 12. 25. A cross-sectional side view of the suction pad shown in FIG. 13.

[0008] Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed description of well-known matters or redundant description of substantially identical configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0009] (Background to the development of the embodiment of the present disclosure) The suction pad in Patent Document 1 does not have the flexibility to hold bags such as plastic bags, making it difficult to hold bags. If the suction pad is highly flexible and has ribs, the flexibility of the suction pad and the ribs make it possible to adsorb an object. However, when the suction pad is pressed against the object to make it adhere closely to the object, the flange (skirt portion) of the suction pad may flip up, with the ribs as a fulcrum. In this case, air flows in, causing suction failure. The skirt portion may have, for example, a trumpet shape.

[0010] In the following embodiment, a suction pad that can prevent the pad body from turning over even when the pad body has high flexibility that allows it to adsorb a bag will be described.

[0011] 1 is an external perspective view of a robot device 15 having a suction pad 11 according to a first embodiment of the present disclosure on a suction hand 13. In the diagrams with arrows indicating directions, the X axis indicates the front-to-rear direction, the Y axis indicates the left-to-right direction, and the Z axis indicates the up-to-down direction. The X axis and Y axis are orthogonal to each other and are included in a horizontal plane. The Z axis is included in a longitudinal plane.

[0012] The suction pad 11 can be suitably used in a robot device 15. Containers 31, cardboard boxes, and the like for transporting cargo (e.g., objects 29) can freely enter and exit the robot device 15. For example, the robot device 15 can transfer cargo from a given container to another container, and can repack cargo between containers. A platform for the containers serves as a stage 27 for sorting.

[0013] The robot device 15 may be an automated machine capable of picking and placing, such as a manipulator (arm robot). In this case, the manipulator has a base installed in a sorting area for luggage (e.g., object 29) or a production line. The manipulator may be configured, for example, with a rotating unit attached to the top of the base and rotating horizontally, an upper arm attached to the rotating unit and swinging back and forth, a forearm attached to the upper arm and swinging up and down, and a wrist with three degrees of freedom attached to the forearm.

[0014] A pair of columns 33, spaced apart in the X direction (front and back), are fixed to each of the left and right base beams 17 and stand upright in the Z direction. The upper ends of the four columns 33 support the four corners of a rectangular base frame 35 that surrounds a horizontal plane. A Y-axis rail 37 extending in the Y direction is supported on the base frame 35. An X-axis rail 39 extending in the X direction is supported on the Y-axis rail 37. A Z-axis rail 41 extending in the Z direction is supported on the X-axis rail 39.

[0015] A moving body 43 is provided on the Z-axis rail 41 so as to be movable up and down (in the Z direction). The moving body 43 may also be referred to as an actuator. The Z-axis rail 41 moves in parallel along the X-axis rail 39 in the front-to-rear direction (X direction) perpendicular to the Z-axis rail 41. The X-axis rail 39 moves in parallel along the Y-axis rail 37 in the left-to-right direction (Y direction) perpendicular to the X-axis rail 39 and the Z-axis rail 41. Therefore, the moving body 43 is movable up and down (in the Z direction), front and back (in the X direction), and left and right (in the Y direction) relative to the stage 27.

[0016] The Z-axis rail 41 that moves the movable body 43, the X-axis rail 39 that moves the Z-axis rail 41 in a direction perpendicular to the Z-axis rail 41, and the Y-axis rail 37 that moves the X-axis rail 39 in a direction perpendicular to the X-axis rail 39 and the Z-axis rail 41 constitute an Cartesian robot 45. The robot device 15 according to the first embodiment is configured by providing the Cartesian robot 45 with a suction hand 13. That is, the Cartesian robot 45 holds the suction hand 13 so that it can move freely in three mutually perpendicular directions. The Cartesian robot 45 also has motors and the like that supply driving forces to move the rails of each axis.

[0017] The robot device 15 also includes a control device (not shown) that controls each component of the robot device 15 (for example, the suction hand 13 and the Cartesian robot 45).

[0018] A vacuum generator 47 is provided above the movable body 43. A support pipe 49 extending in the Z direction is fixed to the lower side of the movable body 43. The upper end (other end) of the support pipe 49 is fixed to the movable body 43 by a mounting piece (not shown). The vacuum generator 47 is connected to the upper end of the support pipe 49 by a connecting tube (not shown). That is, the inner diameter side of the pipe forms a vacuum path communicating with the negative pressure port and the atmospheric release port (not shown) of the vacuum generator 47. A suction pad 11 is fixed to the lower end (one end) of this pipe. The suction pad 11 is a bellows type suction pad formed in a bellows shape. The movable body 43 and the vacuum generator 47 are included in the robot device 15, and may be included in the suction hand 13 or the Cartesian robot 45.

[0019] FIG. 2 is a perspective view of the suction pad 11 according to the first embodiment.

[0020] The suction pad 11 is broadly divided into a pipe connection portion 51, a stopper portion 53, a pressing portion 55, and a pad main body 57. In the suction pad 11 according to the first embodiment, the pad main body 57 is a bellows type having a bellows tube 59. As will be described later, the suction pad 11 does not necessarily have to include the bellows tube 59.

[0021] A nipple portion 61 is formed at the upper end (other end) of the pipe connection portion 51. The nipple portion 61 is connected to, for example, a coupler portion (not shown) provided at the lower end of the support pipe 49. A nut portion 63 having an inner diameter larger than the outer diameter of the nipple portion 61 is formed coaxially below the nipple portion 61 of the pipe connection portion 51. The nut portion 63 is fixed to the coupler portion by threading its female thread portion into the male thread portion of the coupler portion. When the pipe connection portion 51 is fixed to the coupler portion, a vacuum path 65 of the nipple portion 61 is connected to the vacuum path of the support pipe 49. The coupler portion and nipple portion 61 are airtightly connected by an O-ring (not shown).

[0022] FIG. 3 is a cross-sectional side view of the suction pad 11 in a plane including the axis 69 .

[0023] The pipe connection portion 51 has a pad connection portion 71 formed coaxially below the nut portion 63. The pad connection portion 71 is made of a highly rigid resin, metal, or the like. In the suction pad 11 according to the first embodiment, the pad main body 57 has a bellows tube 59, and therefore the upper end of the bellows tube 59 is connected to the pad connection portion 71. The bellows tube 59 is made of a flexible elastic material. Examples of the elastic material include synthetic resin and rubber. The bellows tube 59 has large diameter portions and small diameter portions alternately connected in a direction along the axis 69. This allows the bellows tube 59 to expand and contract in a direction along the axis 69 and to bend in a direction in which the axis 69 bends.

[0024] A thick-walled annular portion 73 with an inner diameter slightly smaller than the outer diameter of the pad connection portion 71 is formed at the upper end of the bellows tube 59. The pad connection portion 71 is inserted into the inner diameter side of the thick-walled annular portion 73, thereby airtightly connecting to the outer diameter of the pad connection portion 71. The thick-walled annular portion 73 connected to the pad connection portion 71 is prevented from coming off by a locking protrusion 75 formed at the lower end of the pad connection portion 71. The inside of the bellows tube 59 connected to the pad connection portion 71 communicates with the negative pressure port and atmospheric release port (not shown) of the vacuum generator 47 via the vacuum path 65 of the pad connection portion 71 and the vacuum path (not shown) of the support pipe 49.

[0025] The stopper portion 53 is formed in a disk shape. The stopper portion 53 is formed of a highly rigid resin, metal, or the like. The stopper portion 53 is fixed to the nut portion 63 while coaxially covering substantially the lower half of the nut portion 63. In other words, movement of the stopper portion 53 in a direction along the axis 69 is restricted. The stopper portion 53 may be fixed to the nut portion 63 by a separate member from the nut portion 63, or may be formed integrally with the nut portion 63. The stopper portion 53 is larger than the outer shape of the nut portion 63, and therefore its lower surface forms an annular surface that is larger than the outer diameter of the bellows tube 59 and protrudes radially outward from the lower surface of the nut portion 63.

[0026] The retaining portion 55 is formed in a cylindrical shape. The retaining portion 55 is formed from a highly rigid resin, metal, or the like. In the first embodiment, the retaining portion 55 is fixed integrally with the stopper portion 53. Therefore, the retaining portion 55 is arranged to hang down coaxially from the annular surface of the stopper portion 53 fixed to the nut portion 63. The inner periphery of the retaining portion 55 is arranged close to the outer periphery of the bellows tube 59. Note that, as will be described later, the retaining portion 55 does not have to be fixed to the nut portion 63.

[0027] The retaining portion 55 may include a flange portion 77 at its lower portion, the flange portion 77 having a conical slope on its upper surface that gradually widens in diameter toward the lower end. The inner periphery of the flange portion 77 has an annular inner peripheral slope that is inclined parallel to the conical slope. The lower end surface of the flange portion 77 may be a horizontal surface perpendicular to the axis 69 (see FIG. 3 ), or a tapered surface whose inner periphery gradually widens in diameter toward the bottom (see FIG. 9A , etc.). The flange portion 77 may not be conical in shape with a conical slope, but may be a part of the cylindrical shape described above and have a shape that extends vertically. The retaining portion 55 may also be lantern-shaped, with a bulging central portion along the axis 69. The flange portion 77 and the portions of the retaining portion 55 other than the flange portion 77 may be formed from the same material.

[0028] The inside of the pad main body 57 forms a suction chamber 79 that communicates with the vacuum path 65. The inner periphery of the suction chamber 79 forms a suction inner surface 81. The suction inner surface 81 opens as an opening of the suction chamber 79 at the lower end of the pad main body 57. One end (lower end) of the pad main body 57 along the axis 69 becomes a skirt portion 85, which has an expanded diameter. That is, the suction pad 11 is provided with an expandable bellows tube 59 that penetrates the retaining portion 55 and is coaxially connected to the pad main body 57, between the stopper portion 53 and the skirt portion 85. In addition, ribs 89 are provided on the suction inner surface 81, and the spaces between the ribs 89 form a flow path that runs from the outer periphery of the skirt portion 85 to the lower end opening 87 and connects to the vacuum path 65. Therefore, the inside of the suction pad 11 of the pad main body 57 forms the suction chamber 79.

[0029] The skirt portion 85 has an outer conical slope whose diameter expands downward. The lower end of the annular retaining portion 55 is disposed opposite the conical slope of the skirt portion 85. In the first embodiment, the upper end of the skirt portion 85 communicates with the lower end opening 87 of the bellows tube 59. The skirt portion 85 alone, or the skirt portion 85 and the bellows tube 59, are formed, for example, from a soft resin or rubber. When the skirt portion 85 is formed, for example, from rubber, it has a predetermined rubber hardness. The rubber hardness decreases as the numerical value decreases, and increases as the numerical value decreases, becoming harder. For example, the rubber hardness is approximately 10° for human skin and 60° or more for an automobile tire. The rubber hardness employed for the skirt portion 85 in the first embodiment is preferably, for example, approximately 20° to 45°. Furthermore, the thickness of the tip of the skirt portion 85 is preferably 0.3 to 0.5 mm. The predetermined rubber hardness of the skirt portion 85 provides adhesion and shape stability to the object 29, such as a bagged product.

[0030] FIG. 4 is a bottom view of the skirt portion 85. FIG.

[0031] The suction inner surface 81 of the skirt portion 85 is provided with a plurality of (e.g., 20) ribs 89 formed in the radial direction around the axis 69. The ribs 89 are formed in a wedge shape that gradually decreases in height as they extend radially outward from the suction inner surface 81. An inner end 91 of the rib 89, which has the highest protrusion height, is located at the lower end opening 87. The outer end of the rib 89, which has the lowest height and is located radially outward, may reach the diameter of the opening of the suction chamber 79 (see FIG. 9A, etc.), or may terminate inside the diameter of the opening of the suction chamber 79 (see FIG. 4).

[0032] The skirt portion 85 has ribs 89 arranged in the radial direction, so that the areas between the ribs have lower strength than the areas where the ribs 89 are provided. As a result, the skirt portion 85 deforms at these low strength areas in response to the object 29, such as a plastic bag, which deforms irregularly, and many suction paths (wrinkled grooves) are likely to be formed in the radial direction on the suction inner surface 81.

[0033] The rib 89 may have a slit 93 formed in the transverse direction perpendicular to the longitudinal direction along the entire radial length thereof. Furthermore, if the slit 93 is present, the skirt portion 85 is more likely to deform downward when the object 29 is attracted to the rib 89. If the slit 93 is present, the inner end 91 of the rib 89 may be located at the position of the slit 93.

[0034] FIG. 5 is a side view of the suction pad 11 when the pad body 57 is at its natural length.

[0035] The suction pad 11 has a length P along the axis 69 of the pressing portion 55 that is set shorter than a natural length L from the stopper portion 53 to the skirt portion 85 of the pad main body 57. The length P is the distance from the lower surface of the stopper portion 53 to the lower end of the flange portion 77. The natural length L is the distance from the lower surface of the stopper portion 53 to the opening of the suction chamber 79 in the skirt portion 85.

[0036] The natural length L is the length of the axis 69 of the bellows tube 59 along the vertical direction when no load of the object 29 is applied to the skirt portion 85. In other words, when the suction pad 11 is not suctioning the object 29, the lower part of the bellows tube 59 that is not covered by the retaining portion 55 and the skirt portion 85 are exposed.

[0037] The bellows tube 59 is stretchable and can be used at its maximum length up to its elastic limit. When the bellows tube 59 reaches its maximum length, the length of the bellows tube 59 exposed from the retaining portion 55 is at its maximum.

[0038] FIG. 6 is a side cross-sectional view of the suction pad 11 when the pad body 57 is contracted.

[0039] When the skirt portion 85 of the pad main body 57 suctions the target object 29, the bellows tube 59 contracts due to the suction action. As the bellows tube 59 contracts, the skirt portion 85 of the pad main body 57 comes into contact with the lower end surface of the retaining portion 55. That is, the pad main body 57 contracts to approximately the same length as the retaining portion 55 (≈P). In this state, the retaining portion 55 is sandwiched between the skirt portion 85 and the stopper portion 53 with a predetermined force. That is, as the bellows tube 59 contracts after suction, the suction pad 11 sandwiches the retaining portion 55 between the stopper portion 53 and the skirt portion 85.

[0040] FIG. 7 is a side view of a suction pad 11 according to a modified example in which the pressing portion 55 is not fixed to the stopper portion 53. In FIG.

[0041] In the suction pad 11, the pressing portion 55 does not have to be fixed to the stopper portion 53. That is, the pressing portion 55 may be movable along the bellows tube 59. In this case, when the axis 69 of the pad main body 57 is aligned vertically, the flange portion 77 of the pressing portion 55 hits the skirt portion 85 due to its own weight, preventing it from falling. In the pad main body 57, the bellows tube 59 is exposed between the stopper portion 53 and the pressing portion 55 for a length (L-P). According to this modification, the load of the pressing portion 55 always acts on the conical slope of the skirt portion 85, making it even less likely for the skirt portion 85 to curl up during initial suction and when adhering to an inclined surface, compared to a configuration in which the pressing portion 55 is fixed to the stopper portion 53. In this modification, the bellows tube 59 bends between the stopper portion 53 and the pressing portion 55 when adhering to an inclined surface. In addition, rather than the flange portion 77 hitting the skirt portion 85 to prevent it from falling, the retaining portion 55 may be connected to the stopper portion 53 via a wire or the like, so that the retaining portion 55 is positioned in a predetermined position.

[0042] FIG. 8 is a side cross-sectional view including the axis 69 of the suction pad 11 according to the modified example shown in FIG.

[0043] When the bellows tube 59 contracts or when a load is applied to the retaining portion 55, the lower end of the retaining portion 55 of the pad main body 57 comes into contact with the conical slope of the skirt portion 85. As described above, a plurality of ribs 89 are arranged in the radial direction on the suction inner surface 81 of the skirt portion 85.

[0044] The retaining portion 55 is a member that prevents the skirt portion 85 from turning up, but depending on the position of the skirt portion 85 that is being pressed, the effect of preventing the skirt portion 85 from turning up may be reduced.

[0045] 9A, 9B, 9C and 9D are schematic diagrams illustrating the turning-up action of the skirt portion 85. FIG.

[0046] As shown in Fig. 9B , when the suction pad 11 comes into contact with the surface to be attracted and starts the suction operation, the pressing portion 55 presses the conical slope 95 radially inward from the inner end 91 of the rib 89, and the point where the inner end 91 and the surface to be attracted intersect becomes a fulcrum 97, and a moment M acts on the skirt portion 85 in a direction that causes the skirt portion 85 to turn up, centered on this fulcrum 97. In contrast, as shown in Fig. 9A , the suction pad 11 has the pressing portion 55 come into contact with the conical slope 95 radially outward from the inner end 91 of the rib 89, so the skirt portion 85 is pressed down outside the fulcrum 97, which suppresses the generation of the moment M and suppresses turning up.

[0047] Furthermore, when the holding position at which the holding portion 55 holds the conical slope 95 of the skirt portion 85 straddles a location where the rib 89 is present on the skirt portion 85 and a location on the skirt portion 85 radially inward of the rib 89 where the rib 89 is not present, the following occurs: That is, as shown in Fig. 9C, when the center c1 in the thickness direction (radial direction) of the cylinder 55a forming the holding portion 55 (in other words, the center of the cylinder thickness) faces the location where the rib 89 is present, curling is suppressed, but when it faces the location where the rib 89 is not present, curling is not suppressed.

[0048] Furthermore, as shown in FIG. 9D, when the position of the retaining portion 55 facing the portion of the skirt portion 85 radially outside the rib 89 where the rib 89 is not present, the skirt portion 85 is prevented from curling up.

[0049] FIG. 10 is an explanatory diagram showing the suction process when the target object 29 is a bagged product.

[0050] The suction pad 11 is configured so that the pressing portion 55 does not restrict deformation of the skirt portion 85 toward the target object 29. Specifically, the pressing portion 55 has no member inside the flange portion 77, and the suction inner surface 81 (i.e., the target object side) does not face the skirt portion 85. As a result, when the suction pad 11 suction-holds the target object 29, such as a bagged product, the skirt portion 85 can deform downward to follow the deformation of the target object 29, as shown in the right diagram of Fig. 10 , and this makes it possible to prevent suction failure due to air flowing in through the opening of the suction chamber 79.

[0051] FIG. 11 is an explanatory diagram showing the adsorption process when the adsorbed surface is an inclined surface.

[0052] As an example, when the object 29 placed on a predetermined horizontal mounting table has an inclined surface to be attracted, the suction pad 11 is first lowered until the skirt portion 85 contacts the object 29. The bellows tube 59 of the suction pad 11 bends, allowing the skirt portion 85 to be attracted to the inclined surface of the object 29. As the suction pad 11 descends, the vacuum generator 47 applies negative pressure to the suction chamber 79, contracting the bellows tube 59 until the retaining portion 55 contacts the skirt portion 85. This completes the suction and holding of the object 29 with an inclined surface.

[0053] Next, the operation of the above-described configuration will be described.

[0054] The suction pad 11 according to the first embodiment includes a pad main body 57 having a skirt portion 85 whose diameter expands toward one end along the axis 69, and a plurality of ribs 89 formed in radial directions around the axis 69 on the suction inner surface 81 on the one end side of the skirt portion 85. The suction pad 11 includes a pressing portion 55 formed in an annular shape (an example of an annular shape) around the axis 69 and disposed opposite a conical slope 95 (an example of a slope) on the other end side of the skirt portion 85. The pressing portion 55 contacts the conical slope 95 radially outward of the radial inner ends 91 of the ribs 89 extending radially of the suction inner surface 81.

[0055] In other words, the suction pad 11 has the following configuration. The suction pad 11 suctions the object 29 and is connected to the vacuum generator 47. The suction pad 11 includes a pad main body 57 that contacts the object 29 and has a skirt portion 85 with a conical slope 95, and a plurality of ribs 89 formed at least in the radial direction on the inside of the skirt portion 85 (e.g., the suction inner surface 81). The suction pad 11 also includes a pressing portion 55 that is disposed to cover the conical slope 95 of the skirt portion 85. When the pressing portion 55 suctions the object 29, it contacts at least the conical slope 95 of the rib 89 that is outer than the end (e.g., the inner end 91) of the pad main body 57 that is closer to the center.

[0056] In the suction pad 11 according to this embodiment, one end of the pad body 57 along the axis 69 becomes a skirt portion 85 that expands in diameter. The pad body 57 having the skirt portion 85 is formed from an elastic material. One end of the skirt portion 85 of the pad body 57 becomes the suction inner surface 81. The suction inner surface 81 is an inner circumferential surface that surrounds a substantially truncated conical space with one end being a circular surface. A plurality of ribs 89 are formed on this suction inner surface 81 in radial directions centered on the axis 69. Each rib 89 extends in the radial direction of the suction inner surface 81 and protrudes from the suction inner surface 81 in a direction approaching the axis 69.

[0057] The suction pad 11 is capable of suctioning bagged products. The skirt portion 85 of the suction pad 11 is thin and highly flexible, allowing it to suction plastic bags. This allows the skirt portion 85 to easily conform to the deformation of the plastic bag when suctioned, but reduces the rigidity and therefore the support load. The radial arrangement of multiple ribs 89 increases the support load without impairing the ability to conform to the deformation of the plastic bag.

[0058] The suction pad 11 can suction not only bagged products but also cardboard boxes as objects 29. In other words, the suction pad 11 can suction both bagged products and cardboard boxes. When suctioning an object 29 that is difficult to deform, such as cardboard boxes, a configuration without ribs 89 increases the success rate of grasping. This is because, if the reaction force received from the object 29 during suction is large, the skirt portion 85, which has reached its maximum outer diameter due to pressure, is displaced toward the other end and simultaneously elastically returns to its original shape to reduce its diameter. As a result, the skirt portion 85 may turn up, which is one of the factors that reduces the success rate of suction.

[0059] This curling of the skirt portion 85 becomes more pronounced when the ribs 89 protrude significantly from the suction inner surface 81. In this case, the curling occurs when an inner end 91 on the radially inner side of the rib 89 extending in the radial direction of the suction inner surface 81 becomes a fulcrum 97 when it comes into contact with the object 29, and a moment M acts on the skirt portion 85 in a curling direction around this fulcrum 97.

[0060] Therefore, the suction pad 11 has a retaining portion 55 formed in an annular shape (one example of an annular shape) centered on the axis 69, and is disposed opposite a conical slope 95 (one example of a slope) on the other end of the skirt portion 85. The retaining portion 55 is made of, for example, resin or metal. The retaining portion 55 contacts the conical slope 95 radially outward of the inner end 91 of the rib 89 in the radial direction.

[0061] When the skirt part 85 of the suction pad 11 tries to rotate in a turning-up direction around the fulcrum 97 due to the reaction force from the object 29, the conical slope 95 is pressed by the restraining part 55 radially outside the fulcrum 97, and it does not separate from the object 29.

[0062] This allows the suction pad 11 to suppress the inflow of air caused by the skirt portion 85 separating from (or turning up) the target object 29, thereby increasing the success rate of grasping. As a result, the suction pad 11 can stably adsorb the target object 29.

[0063] Further, to supplement the configuration of the suppressing portion 55, the suppressing portion 55 may have the following configuration. For example, the suppressing portion 55 may have a cylindrical shape (an example of a tubular shape), and the center c1 in the thickness direction of the cylinder 55a may be in contact with the conical slope 95 of the skirt portion 85 on which at least the rib 89 is formed. The suppressing portion 55 may also be formed along at least the conical slope 95 of the skirt portion 85. The suppressing portion 55 may also be formed in an annular shape. Furthermore, it is sufficient for the suppressing portion 55 to be in contact with at least one point of the skirt portion 85 as long as it is able to suppress curling of the skirt portion 85.

[0064] Furthermore, the suction pad 11 may have the skirt portion 85 disposed at one end along the axis 69 relative to the retaining portion 55. The suction pad 11 may have a stopper portion 53 at the other end of the retaining portion 55, the stopper portion 53 restricting movement along the axis 69. The pad main body 57 may have an expandable bellows tube 59 (an example of a tube) connected to the other end of the skirt portion 85 (for example, provided coaxially and integrally with the skirt portion 85) and passing through the retaining portion 55 between the stopper portion 53 and the skirt portion 85. The length P of the retaining portion 55 along the axis 69 may be shorter than the natural length L of the pad main body 57 from the stopper portion 53 to the skirt portion 85. Note that the tube may have a shape other than a bellows tube.

[0065] In this suction pad 11, a stopper portion 53 is provided on the other end side of the retaining portion 55. Movement of the stopper portion 53 in a direction along the axis 69 is restricted. A flexible bellows tube 59 is provided between the stopper portion 53 and the skirt portion 85 and passes through the retaining portion 55. The bellows tube 59 is made of a softer material than the retaining portion 55. The suction pad 11 has various portions with increasing hardness in the following order: skirt portion < bellows tube < retaining portion. The retaining portion 55 may be rigid. The stopper portion 53 is provided with an opening or the like that connects the inside of the bellows tube 59 to the vacuum path 65 of the vacuum generator 47. The retaining portion 55 is formed, for example, in an annular or cylindrical shape. The bellows tube 59, whose other end abuts against the stopper portion 53, is restricted from moving toward the other end (upward) by the stopper portion 53. The bellows tube 59 has a tip (one end) that passes through the retaining portion 55 and is connected to the skirt portion 85 .

[0066] Here, the length P of the pressing portion 55 along the axis 69 is shorter than the natural length L from the stopper portion 53 to the skirt portion 85. The natural length L is the length when the axis 69 of the bellows tube 59 is aligned vertically and no load of the object 29 is applied to the pad main body 57 at the lower end of the bellows tube. In other words, when the pad main body 57 is not suctioning the object 29, the portion of the suction pad 11 that is not covered by the pressing portion 55 is exposed. In other words, when the bellows tube 59 is at its maximum length, the pressing portion 55 is not in contact with the conical slope 95 of the skirt portion 85. This exposed portion of the bellows tube 59 of the suction pad 11 is bendable. In other words, the opening of the suction chamber 79 can be oriented in any direction within 360° around the axis 69.

[0067] 3 and 11, the bellows tube 59 of the suction pad 11 may be formed to be bendable in a direction bending the axis 69. The outer periphery of the bellows tube 59 and the inner periphery of the retaining portion 55 may be disposed close to each other.

[0068] In this suction pad 11, the surface of the object 29 to which the pad body 57 is attached is not necessarily horizontal. When the surface of the object 29 to be attached is inclined, when the pad body 57 descends vertically and reaches the inclined surface, a circumferential portion of the skirt portion 85 first abuts against the inclined surface. However, as the pad body 57 continues to descend, the bellows tube 59 exposed from the retaining portion 55 begins to bend due to a reaction force from the inclined surface. The bellows tube 59 eventually bends until the skirt portion 85 becomes parallel to the inclined surface. As a result, the entire periphery of the tip of the skirt portion of the pad body 57 tightly contacts the object 29 without any gaps. Depending on the inclination angle of the inclined surface, the suction pad 11 may move downward in the inclined direction, facilitating bending.

[0069] Next, when negative pressure acts on the suction chamber 79 of the pad main body 57 via the bellows tube 59, the skirt portion 85 comes into close contact with the object 29, and the bellows tube 59 begins to contract. As the bellows tube 59 contracts, the length of the suction pad 11 from the stopper portion 53 to the skirt portion 85 becomes the same as the length P of the retaining portion 55 in that direction, and the conical slope 95 of the skirt portion 85 comes into contact with the tip of the retaining portion 55. Furthermore, as the bellows tube 59 contracts, the retaining portion 55 is pressed against the conical slope 95 of the skirt portion 85. In other words, when the suction pad 11 is adsorbed, the bellows tube 59 contracts and the retaining portion 55 presses the skirt portion 85.

[0070] Furthermore, the retaining portion 55 of the suction pad 11 does not need to be fixed to the stopper portion 53 .

[0071] In this suction pad 11, the retaining portion 55 is not fixed to the stopper portion 53. Therefore, the retaining portion 55 can be easily removed and replaced. Furthermore, when the bellows tube 59 has its natural length L, the retaining portion 55 is free to move in the longitudinal direction of the bellows tube 59. When the axis 69 of the bellows tube 59 is aligned vertically, the lower end of the retaining portion 55 comes into contact with the conical slope 95 of the skirt portion 85 due to its own weight, thereby restricting its downward movement. In other words, the load of the retaining portion 55 is applied to the skirt portion 85.

[0072] On the other hand, when the bellows tube 59 contracts due to the suction action when the object 29 is adsorbed, the lower end of the retaining portion 55 is pushed up by the skirt portion 85. When the pad main body 57 contracts to a length P that is substantially the same as the retaining portion 55, the upper end of the retaining portion 55 comes into contact with the stopper portion 53, and further lifting is restricted. In this state, the retaining portion 55 is sandwiched and held between the skirt portion 85 and the stopper portion 53 with a predetermined force (see FIG. 6).

[0073] Furthermore, in the suction pad 11 , the bellows tube 59 may be shortened after suction, and the outer periphery of the entire bellows tube 59 (overall length) may be covered by the inner periphery of the holding portion 55 .

[0074] In this suction pad 11, the outer periphery of the bellows tube 59 and the inner periphery of the retaining portion 55 may be arranged in close proximity. As a result, when the suction pad 11 suctions the object 29, the bellows tube 59 contracts and is covered by the retaining portion 55, and the entire inner periphery of the bellows tube 59 comes in close proximity to the outer periphery of the bellows tube 59. Since the entire outer periphery of the bellows tube 59 is in close proximity to the inner periphery of the retaining portion 55, lateral displacement (i.e., shaking inside the retaining portion 55) is suppressed. The smaller the gap between the outer periphery of the bellows tube 59 and the inner periphery of the retaining portion 55, which occurs when they are arranged in close proximity, the better. However, contact is not preferable because it inhibits the expansion and contraction of the bellows tube 59.

[0075] Therefore, before the bellows tube 59 contracts, i.e., before suction, the suction pad 11 ensures the flexibility of the bellows tube 59, making it easy to suction the object 29. For example, even if the suction surface of the suction pad 11 that suctions the object 29 is inclined, the shape of the bellows tube 59 can follow the shape of the inclined surface. Furthermore, after the bellows tube 59 contracts, i.e., after suction, the suction pad 11 reduces the flexibility of the bellows tube 59 and can stably hold the object 29 using the retaining portion 55. Note that when suctioning the object 29, the bellows tube 59 may contract to the maximum extent, making the bellows tube 59 the shortest possible length.

[0076] Furthermore, the suction pad 11 can prevent the skirt portion 85 from curling up because the outer periphery of the entire (full length) bellows tube 59 is covered by the inner periphery of the retaining portion 55. At the same time, when the suction pad 11 suctions the object 29, the skirt portion 85 and the stopper portion 53 sandwich the retaining portion 55 around the suction pad 11, so that the section from the stopper portion 53 to the pad main body 57 becomes a rigid body with restricted bending. This prevents lateral shaking of the object 29 due to inertial force even when the Cartesian robot 45 is activated and the suction pad 11 moves horizontally. In other words, the suction pad 11 applies suction to compress the bellows tube 59 inside the retaining portion 55, thereby enabling the suction pad 11 to stably grip the object 29. At this time, the outer periphery of the bellows tube 59 and the inner periphery of the retaining portion 55 are positioned close to each other, so lateral shaking caused by rattling of the bellows tube 59 within the retaining portion 55 is also prevented. The outer periphery of the bellows tube 59 and the inner periphery of the retaining portion 55 may not be disposed close to each other.

[0077] Furthermore, in the suction pad 11, the pressing portion 55 does not need to face the suction inner surface 81 (an example of an inner surface) on one end side of the skirt portion 85. For example, any part included in the pressing portion 55 may not be located on the suction inner surface 81, and the pressing portion 55 may not overlap the suction inner surface 81.

[0078] This suction pad 11 is configured so that when the suction pad 11 suctions an object 29, such as a plastic bag, the deformation of the skirt portion 85 toward the object is not inhibited by the retaining portion 55. For example, the retaining portion 55 does not face the suction inner surface 81 at one end of the skirt portion 85, and therefore does not restrict the deformation of the skirt portion 85 toward the object. This allows the skirt portion 85 to easily follow the deformation of the plastic bag or the like that occurs during suction, increasing the success rate of grasping the object 29. As a result, the suction pad 11 can stably suction the object 29.

[0079] In addition, the suction pad 11 may have the pressing portion 55 and the stopper portion 53 fixed integrally.

[0080] In this suction pad 11, the retaining portion 55 and the stopper portion 53 are fixed integrally. "Integrated" means that the retaining portion 55 and the stopper portion 53 may be a single member, or may be separate members joined together. As a result, when the bellows tube 59 is at its natural length L, the exposed portion of the bellows tube 59 is located between the lower end of the retaining portion 55 and the skirt portion 85.

[0081] In other words, if the retaining portion 55 is not fixed to the stopper portion 53, and the bellows tube 59 has its natural length L, the exposed portion of the bellows tube 59 will be between the stopper portion 53 and the upper end of the retaining portion 55. This is because the retaining portion 55, which has been lowered by gravity, will come into contact with the skirt portion 85 and stop.

[0082] On the other hand, in the suction pad 11 in which the retaining portion 55 is fixed to the stopper portion 53, the exposed portion of the bellows tube 59 is between the retaining portion 55 and the skirt portion 85. Therefore, when the bellows tube 59 bends to follow the inclined surface of the target object 29, the suction pad 11 can increase the degree of freedom of bending of the bellows tube 59 compared to a configuration in which the retaining portion 55 comes into contact with the skirt portion 85 and stops.

[0083] Therefore, according to the suction pad 11 of the first embodiment, even if the pad main body 57 has high flexibility that allows it to adsorb a bag, it is possible to prevent the pad main body 57 from being turned up.

[0084] FIG. 12 is a perspective view of the suction pad 11 without the bellows tube 59. FIG.

[0085] (Other embodiments) In the above-mentioned embodiment 1, a configuration example in which the pad main body 57 has a bellows tube 59 has been described, but the suction pad according to the present disclosure may also be a suction pad 99 that does not have a bellows tube 59 as shown in FIG. 12 .

[0086] FIG. 13 is a side view of the suction pad 99 shown in FIG.

[0087] The suction pad 99 without the bellows tube 59 can have a shorter pressing portion 55 by the amount corresponding to the omission of the bellows tube 59. That is, the suction pad 99 has the same configuration as the suction pad 11 according to the first embodiment, except that the bellows tube 59 is omitted and the pressing portion 55 is shorter.

[0088] FIG. 14 is a side cross-sectional view of the suction pad 99 shown in FIG. 13, including the axis 69.

[0089] The suction pad 99 has a thick annular portion 73 connected to the pad connecting portion 71. The thick annular portion 73 is directly connected to the skirt portion 85. In other words, the pad main body 101 is formed with a shorter length from the thick annular portion 73 to the skirt portion 85 because the bellows tube 59 is omitted. This suction pad 99 also makes it possible to keep the axial length small (to achieve a compact size and shape), while using the retaining portion 55 to prevent the skirt portion 85 from curling up.

[0090] In the first embodiment and other embodiments, the restraining portion 55 does not necessarily have to restrain the entire skirt portion 85. For example, the restraining portion 55 may restrain at least one point on the periphery of the skirt portion 85. In addition, when the pad main body 57 is made of a soft material, it is preferable that the restraining portion 55 restrains more than one point.

[0091] As a result, the present disclosure describes at least the following: Note that, in parentheses, examples of components corresponding to the above-described embodiments are given, but the present disclosure is not limited to these.

[0092] (Item 1) A suction pad (suction pad 11) that suctions an object (object 29) and is connected to a vacuum generator (vacuum generator 47), comprising: a pad body (pad body 101) that contacts the object and has a skirt portion (skirt portion 85) that has a slope (conical slope 95), and a plurality of ribs (ribs 89) formed at least in a radial direction inside the skirt portion; and a retaining portion (retaining portion 55) that is arranged to cover the slope of the skirt portion, and when suctioning the object, the retaining portion contacts the slope at least on the outer side of the end of the rib that is closest to the center of the pad body.

[0093] As a result, when the suction pad adsorbs an object, even if the radially outer side of the flexible skirt portion tries to curl up around the end of the rib on the center side of the pad body as a fulcrum, the skirt portion is held down by the retaining portion, thereby preventing the skirt portion from curling up. Therefore, the suction pad can prevent the skirt portion from curling up even if the skirt portion has high flexibility enough to adsorb a bag.

[0094] (Item 2) The suction pad according to item 1, wherein the pressing portion contacts at least one point of the skirt portion.

[0095] This allows the suction pad to prevent the skirt portion from curling up even if there is little contact between the smart portion and the pressing portion.

[0096] (Item 3) The suction pad according to item 1 or 2, wherein the pressing portion is formed in a ring shape.

[0097] This allows the suction pad to be held down by the holding portion over the entire periphery of the skirt portion, making it even more difficult for the skirt portion to be turned up.

[0098] (Item 4) The suction pad according to any one of Items 1 to 3, wherein the pressing portion has a cylindrical shape, and the center of the cylinder in the thickness direction is in contact with at least the inclined surface of the skirt portion on which the rib is formed.

[0099] This allows the retaining portion of the suction pad to come into contact with the slope at least more at the position where the rib is formed than at the position where the rib is not formed, thereby preventing the skirt portion of the suction pad from flipping up with the inner end of the rib as a fulcrum.

[0100] (Item 5) The suction pad according to any one of Items 1 to 4, wherein the pressing portion is formed at least along the inclined surface of the skirt portion.

[0101] This allows the suction pad to easily press the slope of the skirt portion with a uniform force using the pressing portion, making it even more difficult for the skirt portion to be turned up.

[0102] (Item 6) The suction pad according to any one of Items 1 to 5, wherein the pressing portion does not face the inner surface of the skirt portion.

[0103] This allows the suction pad to suction a bag-shaped object without the restraining portion interfering with the deformation of the skirt portion toward the object. This allows the suction pad to easily follow the deformation of a plastic bag or other object that deforms during suction, increasing the success rate of grasping the object. This allows the suction pad to suction a bag-shaped object stably.

[0104] (Item 7) The suction pad according to any one of items 1 to 6, wherein the skirt portion is disposed on one end side along the axis (axis 69) relative to the retaining portion, and the other end side along the axis of the retaining portion is provided with a stopper portion (stopper portion 53) that restricts movement along the axis, the pad main body is connected to the other end side of the skirt portion and is provided with an expandable tube (bellows tube 59) that passes through the retaining portion between the stopper portion and the skirt portion, and the length (length P) of the retaining portion in the direction along the axis is shorter than the natural length (natural length L) of the pad main body from the stopper portion to the skirt portion.

[0105] As a result, when the suction pad is not suctioning an object, i.e., when the pad body is at its natural length, a portion of the tube is exposed and not covered by the retaining portion. This ensures the tube has the freedom to bend, making it easier to suction an object. Furthermore, after suction (after suction), the tube shrinks, so the retaining portion can prevent the skirt from curling up.

[0106] (Item 8) The suction pad according to Item 7, wherein the retaining portion is not in contact with the inclined surface of the skirt portion when the tube is at its maximum length.

[0107] As a result, when the suction pad is at its maximum length, a part of the tube is exposed and not covered by the retaining portion, so that the tube can bend freely, making it easier to suction the object.

[0108] (Item 9) The suction pad according to item 7 or 8, wherein the tube is formed to be freely bendable in a direction bending the axis, and an outer periphery of the tube and an inner periphery of the pressing portion are disposed close to each other.

[0109] This allows the suction pad to conform to the shape of the inclined surface of the pipe, even if the surface that suctions the object is inclined. Also, when the suction pad tries to move the object horizontally after suctioning it, the inner periphery of the retaining part is close to the outer periphery of the pipe, so that the retaining part can limit bending of the pipe and prevent the object from falling due to lateral shaking.

[0110] (Item 10) The suction pad according to any one of items 7 to 9, wherein the tube shortens after suction, and the entire outer periphery of the tube is covered by the inner periphery of the pressing portion.

[0111] As a result, after suction, the entire radially outer periphery of the suction pad on the pipe is covered by the retaining portion, so that the retaining portion can restrict lateral shaking over the entire pipe.

[0112] (Item 11) The suction pad according to any one of Items 7 to 10, wherein the tube is a bellows tube.

[0113] As a result, by using the bellows tube, the suction pad can easily ensure the flexibility of the bellows tube and prevent the skirt portion from curling up after suction.

[0114] (Item 12) The suction pad according to any one of Items 7 to 11, wherein the pressing portion is not fixed to the stopper portion.

[0115] This allows the suction pad to position the pressing portion with a degree of freedom in terms of the position of the pressing portion relative to the stopper when not in suction.

[0116] (Item 13) The suction pad according to any one of Items 7 to 11, wherein the pressing portion and the stopper portion are fixed integrally.

[0117] As a result, when the tube is at its natural length, the exposed portion of the tube is between the lower end of the retaining part and the skirt part, so the lower part of the tube is exposed from the retaining part. Therefore, the suction pad can easily deform to follow the suction surface of the object when suctioning the object, making it easier to suction the object.

[0118] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present disclosure is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0119] The present disclosure is useful for suction pads and the like that can prevent skirt portions from turning up even when the skirt portions have high flexibility that allows them to adsorb bags.

[0120] REFERENCE SIGNS LIST 11 suction pad 53 stopper portion 55 holding portion 57 pad body 59 bellows tube 69 axis 81 suction inner surface 85 skirt portion 89 rib 91 inner end 95 conical slope 99 suction pad 101 pad body L natural length P length in the direction along the axis of the holding portion

Claims

1. A suction pad which adsorbs an object and is connected to a vacuum generator, comprising: a pad body having a skirt portion which contacts the object and has a slope, and a plurality of ribs formed inside the skirt portion in at least a radial direction; and a retaining portion which is arranged to cover the slope of the skirt portion, wherein when adsorbing the object, the retaining portion contacts the slope of at least one of the plurality of ribs on the outer side of the end of the pad body toward the center.

2. The suction pad according to claim 1, wherein the pressing portion contacts at least one point of the skirt portion.

3. The suction pad according to claim 1, wherein the pressing portion is formed in a ring shape.

4. The suction pad according to claim 1, wherein the pressing portion has a cylindrical shape, and the center of the cylindrical shape in the thickness direction is in contact with at least the inclined surface of the skirt portion on which the rib is formed.

5. The suction pad according to claim 1, wherein the pressing portion is formed at least along the inclined surface of the skirt portion.

6. The suction pad according to claim 1, wherein the pressing portion does not face the inner surface of the skirt portion.

7. The suction pad described in claim 1, wherein the skirt portion is arranged at one end along the axis of the retaining portion, the suction pad is arranged at the other end along the axis of the retaining portion and further comprises a stopper portion that restricts movement in a direction along the axis, the pad body is connected to the other end of the skirt portion and further has an expandable tube that passes through the retaining portion between the stopper portion and the skirt portion, and the length of the retaining portion in the direction along the axis is shorter than the natural length of the pad body from the stopper portion to the skirt portion.

8. The suction pad according to claim 7, wherein the retaining portion is not in contact with the inclined surface of the skirt portion when the tube is at its maximum length.

9. The suction pad according to claim 7, wherein the tube is formed so as to be freely bent in a direction bending the axis, and the outer periphery of the tube and the inner periphery of the pressing portion are disposed adjacent to each other.

10. The suction pad according to claim 7, wherein the tube shortens after suctioning the object, so that the entire outer periphery of the tube is covered by the inner periphery of the retaining portion.

11. The suction pad according to claim 7, wherein the tube is a bellows tube.

12. The suction pad according to claim 7, wherein the pressing portion is not fixed to the stopper portion.

13. The suction pad according to claim 7, wherein the pressing portion and the stopper portion are fixed integrally.

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