Suction pad

Abstract

This suction pad includes: a first pad having an inclined surface; and a second pad having an outer shape larger than that of the first pad, covering the inclined surface of the first pad, and having at least an upper part in close contact with the first pad. The second pad is formed of a material softer than the first pad, and has a plurality of ribs arranged on an outer periphery of the first pad on the suction surface side.

Description

suction pad

[0001] The present disclosure relates to suction pads.

[0002] Conventionally, there has been known a suction cup for suction-conveying an article, characterized in that the suction cup is configured by providing a small suction cup that opens around the lower end of the intake pipe and is fixed thereto, and a large suction cup that surrounds the small suction cup and opens concentrically with the small suction cup and is fixed thereto (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2003-225880

[0004] The present disclosure provides a suction pad that can grip both bag-shaped objects and box-shaped objects and can prevent the pad from becoming too large.

[0005] One aspect of the present disclosure is an adsorption pad comprising a first pad having a sloped surface, and a second pad having an outer shape larger than that of the first pad, covering the sloped surface of the first pad, and having at least an upper portion in close contact with the first pad, wherein the second pad is formed of a material softer than the first pad and has a plurality of ribs arranged more peripherally on the adsorption surface side than the first pad.

[0006] According to the present disclosure, both bag-shaped objects and box-shaped objects can be grasped, and the size can be prevented from increasing.

[0007] 1. A perspective view of a robot device having a suction pad in a suction hand according to a first embodiment of the present disclosure. 2. A side view of the suction pad. 3. A perspective view of the suction pad shown in FIG. 2, viewed obliquely from below. 4. A cross-sectional view of a main part of the suction pad, taken along a plane including an axis. 5. A cross-sectional view of a main part of the suction pad before contacting a box. 6. A cross-sectional view of a main part of the suction pad in contact with a box. 7. A cross-sectional view of a main part of the suction pad according to a comparative example, which has contacted a box. 8. A cross-sectional view of a main part of the suction pad gripping a box. 9. A cross-sectional view of a main part of the suction pad before contacting a bag. 10. A cross-sectional view of a main part of the suction pad in contact with a bag. 11. A cross-sectional view of a main part of the suction pad gripping a bag.

[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 cup for suction and transport in Patent Document 1 does not have the flexibility and ribs to easily hold bags, making it difficult to hold bags. On the other hand, the suction force of the bag pad is likely to be weaker (easier to become weaker) than that of a regular pad. Furthermore, if a separate bag pad is provided from a regular pad, it is necessary to switch between the bag pad and the regular pad using a pad changer, which increases the size of the suction and transport suction cup.

[0010] In the following embodiment, a suction pad will be described that can grip both bag-shaped objects and box-shaped objects even when provided with ribs, and that can prevent the pad from becoming too large.

[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. An AGV (Automatic Guided Vehicle) for transporting cargo (e.g., an object 29), a bin, or the like can freely enter and exit the robot device 15, and a platform for the AGV or the like 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 is translated 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 is translated 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 51 (see FIG. 3 ) that communicates 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 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 side view of the suction pad 11. FIG.

[0020] The suction pad 11 is fixed to the lower end of the support pipe 49. The suction pad 11 includes a large pad 55 (pad main body) (see FIG. 4) whose diameter expands downward with its axis 53 aligned along the vertical axis. One end of the axis 53 corresponds to the downward direction, and the other end of the axis 53 corresponds to the upward direction. The suction pad 11 also includes a bag pad 57 that covers the large pad 55, a cover 59 that covers the bag pad 57, a bellows tube 61 that is interposed between the large pad 55 and the support pipe 49, and a reinforcing member 63 (see FIG. 4) that is fixed inside the lower end of the bellows tube 61. A coupler 65, for example, is connected to the upper end of the bellows tube 61. The coupler 65 is detachably connected to a nipple (not shown) attached to the lower end of the support pipe 49.

[0021] FIG. 3 is a perspective view of the suction pad 11 shown in FIG. 2 as viewed obliquely from below.

[0022] The suction pad 11 has a bag pad 57, a large pad 55, a bellows tube 61, and a reinforcing member 63 arranged coaxially around the axis 53. The inside of the large pad 55 forms a suction chamber 67 that communicates with the vacuum path 51. The bag pad 57 has, on its lower surface, ribs 69 (described below) arranged in radial directions around the axis 53.

[0023] 4 is a cross-sectional view of a main part of the suction pad 11 taken along a plane including the axis 53. In FIG. 4, one side of the axis 53 is mainly shown.

[0024] The large pad 55 has a conical slope 71 on its upper surface. The conical slope 71 is an annular truncated cone-shaped slope in which the top of the cone is cut off by a plane parallel to the circular base. The cone here is a right circular cone in which a line perpendicular to the center of the circular base passes through the vertex (top).

[0025] In the large pad 55, the upper part of the conical slope 71 is a small-diameter upper part 73, and the lower part of the conical slope 71 is a large-diameter lower part 75. In the large pad 55, the small-diameter upper part 73 and the large-diameter lower part 75 are open and communicate with each other. That is, in the suction pad 11, the inside of this large pad 55 is a suction chamber 67 that communicates with the vacuum path 51.

[0026] The bag pad 57 is placed over the upper surface of the large pad 55. The bag pad 57 is formed in an annular shape extending at approximately the same inclination angle along the conical slope 71 of the large pad 55. The bag pad 57 has an open upper end forming an inner diameter portion 77 and an open lower end forming a flared protruding portion 79. The bag pad 57 has its inner diameter portion 77 in contact with the small diameter upper portion 73 of the large pad 55, and is loosely stacked on the conical slope 71 of the large pad 55 due to its own weight. The bag pad 57 is fixed to another portion of the suction pad 11 so that the inner diameter portion 77 does not separate from the small diameter upper portion 73.

[0027] Here, the other portion is, for example, the lower narrow inclined wall 81 of the bellows tube 61 connected to the upper end of the large pad 55. The lower narrow inclined wall 81 is a connection portion where the bellows tube 61 and the large pad 55 are connected. A fixing ring 83 having a triangular cross section is formed on the inner diameter portion 77 of the bag pad 57. The fixing ring 83 is fixed, for example, by adhesive, to the underside of the lower narrow inclined wall 81 at the valley portion (recessed corner portion) where the large pad 55 and the lower narrow inclined wall 81 intersect. In other words, the bag pad 57 may be connected to the outside of the bellows tube 61.

[0028] That is, the lower surface of the lower narrow inclined wall 81 forms an adhesive area 85. Therefore, the bag pad 57 is not fixed to the conical inclined surface 71 of the large pad 55. A free area Fa is formed between the bag pad 57 and the conical inclined surface 71, allowing relative displacement. The configuration of the bellows tube 61 will be described in detail later. The bag pad 57 may be fixed to the conical inclined surface 71 of the large pad 55 by adhesive or the like, that is, may be connected to the conical inclined surface 71 of the large pad 55.

[0029] Note that air does not escape between the bag pad 57 and the conical slope 71 of the large pad 55. Furthermore, if the bag pad 57 is made of silicone, even if the bag pad 57 is not bonded to the adhesive area 85, the silicone will adhere closely to the conical slope 71, preventing air from escaping between the bag pad 57 and the conical slope 71 of the large pad 55. Therefore, bonding with an adhesive is not essential. For example, the bag pad 57 and the large pad 55 may be integrally molded. Note that by bonding the bag pad 57 with an adhesive in the adhesive area 85, the suction pad 11 can prevent the bag pad 57 from sliding down the conical slope 71 of the large pad 55 due to the weight of the bag pad 57 when it adsorbs a heavy bag object.

[0030] The bag pad 57 has a protruding portion 79 that protrudes outward from the large-diameter lower portion 75 of the large pad 55. For example, when the object 29 is not being sucked, this protruding direction is parallel to the conical slope 71 of the large pad 55. Therefore, in this state, the bag pad 57, like the large pad 55, expands in diameter downward with its axis 53 aligned along the vertical axis.

[0031] The bag pad 57 is formed of a softer material than the large pad 55. The bag pad 57 is formed, for example, thinner than the large pad 55. The bag pad 57 is formed, for example, of a soft resin or rubber. When the bag pad 57 is formed, for example, of rubber, it has a predetermined rubber hardness. The rubber hardness becomes softer as the numerical value becomes smaller, and harder as the numerical value becomes larger. For example, the rubber hardness is about 10° for human skin and 60° or more for an automobile tire. The rubber hardness adopted for the bag pad 57 in the first embodiment is preferably equal to or less than that of human skin. By having the predetermined rubber hardness, the bag pad 57 has adhesion to the object 29, such as a bagged product, and shape stability.

[0032] The bag pad 57 has a plurality of ribs 69 on the lower surface (inner surface) of the protruding portion 79. Each of the plurality of ribs 69 is disposed in a radial direction about the axis 53 and protrudes downward. The ribs 69 are formed in a wedge shape that becomes thinner in the protruding direction of the protruding portion 79.

[0033] In bag pad 57, ribs 69 are arranged along the radial direction, so that the areas between the ribs are weaker than the areas where ribs 69 are provided. As a result, protruding portion 79 deforms at this weak area in response to an object 29 such as a vinyl bag that deforms irregularly, and many suction paths (wrinkled grooves) tend to form in the radial direction on the suction inner surface.

[0034] The rib 69 may have a slit 87 formed in the transverse direction perpendicular to the longitudinal direction along the entire radial length of the rib 69. Furthermore, if the slit 87 is present, the protruding portion 79 is more likely to deform downward when the object 29 is attracted.

[0035] The suction pad 11 further includes an annular cover 59. The cover 59 covers the bag pad 57 from above and is positioned opposite the bag pad 57. The cover 59 abuts against the protruding portion 79 of the bag pad 57 that has been displaced upward. That is, the cover 59 abuts against the protruding portion 79 of the bag pad 57 that has been displaced toward the cover 59. The cover 59 is formed of a material harder than the bag pad 57 (protruding portion 79). In cross section, the cover 59 includes a fixing piece 89 whose radially inner side is parallel to the lower narrow inclined wall 81 and a pressing piece 91 whose radially outer side is approximately parallel to the conical inclined surface 71 of the large pad 55. The upper surface of the fixing piece 89 of the cover 59 is fixed to the adhesive area 85 of the lower narrow inclined wall 81.

[0036] The large pad 55 is connected to a coaxial bellows tube 61 at its small-diameter upper portion 73. The bellows tube 61 has large-diameter portions 93 and small-diameter portions 95 that are alternately connected. For example, one large-diameter portion 93 is sandwiched between upper and lower small-diameter portions 95. In this case, the large-diameter portion 93 and the upper small-diameter portion 95 are connected by an upper narrow inclined wall 97. The large-diameter portion 93 and the lower small-diameter portion 95 are connected by a lower narrow inclined wall 81.

[0037] The upper narrow inclined wall 97 is a tapered wall in which the large diameter portion 93 decreases in diameter in the upward direction, and the lower narrow inclined wall 81 is a tapered wall in which the large diameter portion 93 decreases in diameter in the downward direction.

[0038] In other words, one small diameter portion 95 is sandwiched between the upper and lower large diameter portions 93. At this time, the small diameter portion 95 and the upper large diameter portion 93 are connected by the lower thin inclined wall 81. The small diameter portion 95 and the lower large diameter portion 93 are connected by the upper thin inclined wall 97.

[0039] A reinforcing member 63 is fixed to the inside of the connection portion between the bellows tube 61 and the large pad 55. The reinforcing member 63 is a member that restricts radial inward and outward deformation of the large pad 55. The reinforcing member 63 is formed of a material harder than the large pad 55. The connection portion is, for example, the lower narrow inclined wall 81 at the lowest end of the bellows tube 61. The reinforcing member 63 is fixed in close contact with the inner circumferential surface of the lower narrow inclined wall 81 with an adhesive or the like. Therefore, the lower narrow inclined wall 81 also contributes to the supporting strength of the cover 59. Furthermore, the cover 59 fixed to the lower narrow inclined wall 81 also structurally secures the fixing ring 83 of the bag pad 57 in a manner that makes it difficult for it to come off.

[0040] In the suction pad 11, the large pad 55 may be formed integrally with the bellows tube 61. "Integrated" means that the bellows tube 61 and the large pad 55 may be a single member, or separate members joined together. The separate members may be made of the same material or different materials.

[0041] Next, the suction operation of the suction pad 11 will be described.

[0042] 5, 6, and 8 to 12, which will be described later, show cross-sectional views of the suction pad 11 taken along a plane including the axis 53, and mainly illustrate one side of the axis 53. Also, in FIGS. 5, 6, and 8 to 12, illustrations are simplified by omitting illustration of some components, such as the fixed ring 83. The same applies to the illustration of the suction pad 99 according to the comparative example in FIG. 7.

[0043] [When the Object is a Box] FIG. 5 is a cross-sectional view of a main part of the suction pad 11 before it comes into contact with a box as the object 29. As shown in FIG.

[0044] When the object 29 is made of a hard material such as a box, the suction pad 11 is first lowered in a direction approaching the object 29 placed on a predetermined placing table. The suction pad 11 is in a state where the bag pad 57 is in contact with the conical slope 71 of the large pad 55, and the protruding portion 79 of the bag pad 57 protrudes from the large-diameter lower portion 75 of the large pad 55. In this state, the bag pad 57 extends linearly along the conical slope 71 of the large pad 55.

[0045] FIG. 6 is a cross-sectional view of a main part of the suction pad 11 in contact with the box.

[0046] Of the suction pad 11, the bag pad 57 is the first to come into contact with the object 29. When the suction pad 11 is further lowered and pressed against the object 29 with the ribs 69 in contact with the object 29, the ribs 69 are pushed upward by the reaction force from the object 29. As a result, the bag pad 57 attempts to displace upward, but the protruding tip of the protruding portion 79 hits the cover 59, restricting the protruding tip from displacing further. In other words, the cover 59 restricts the tip of the bag pad 57 from freely deforming, making it difficult for the bag pad 57 to turn up.

[0047] FIG. 7 is a cross-sectional view of a main part of a suction pad 99 according to a comparative example that comes into contact with a box.

[0048] In the suction pad 99 without the cover 59 according to the comparative example, the protruding portion 79 pushed up by the rib 69 is not restricted in displacement by the cover 59, so the tip of the protruding portion bounces up (turns up).

[0049] FIG. 8 is a cross-sectional view of a main part of the suction pad 11 gripping a box.

[0050] In the suction pad 11 according to the first embodiment, as the suction pad 11 further descends, the large-diameter lower portion 75 of the large pad 55 comes into close contact with the object 29. This prevents air from leaking between the large-diameter lower portion 75 and the object 29, and the suction chamber 67 approaches a vacuum. This completes the suction of the object 29 by the suction pad 11. Therefore, the box serving as the object 29 can be gripped by the suction of the large pad 55. The suction force of the large pad 55 is stronger than the suction force of the bag pad 57.

[0051] Furthermore, as the suction pad 11 further descends, the tip of the protruding portion 79 is pressed against the cover 59, making it difficult for the tip of the protruding portion 79 to separate from the object 29 and preventing the protruding portion 79 from curling up. As the ribs 69 are pushed up by the object 29, the bag pad 57 is raised above the conical slope 71 of the large pad 55 and separated from the large pad 55.

[0052] [When the Object is a Bag] FIG. 9 is a cross-sectional view of a main part of the suction pad 11 before it comes into contact with a bag as the object 29. As shown in FIG.

[0053] When the object 29 is made of a soft material such as a bag, the suction pad 11 is first lowered in a direction that causes the suction pad 11 to approach the object 29 placed on the upstream transfer table 19. The suction pad 11 is in a state in which the bag pad 57 is in contact with the conical slope 71 of the large pad 55, and the protruding portion 79 of the bag pad 57 protrudes from the large-diameter lower portion 75 of the large pad 55. In this state, the bag pad 57 extends linearly along the conical slope 71 of the large pad 55.

[0054] FIG. 10 is a cross-sectional view of a main part of the suction pad 11 in contact with the bag.

[0055] Of the suction pad 11, the bag pad 57 is the first to come into contact with the object 29. When the suction pad 11 is further lowered with the rib 69 in contact with the object 29, the protruding portion 79 of the bag pad 57 comes into contact with the bag, blocking the inner surface (lower surface) of the bag pad 57. A space also exists between the large pad 55 and the object 29. Therefore, the suction chamber 67 of the large pad 55 communicates with the inner surface of the bag pad 57, negative pressure is created in the suction chamber 67, and the protruding portion 79 and the large pad 55 deform in a direction that reduces the volume of the suction chamber 67.

[0056] FIG. 11 is a cross-sectional view of a main part of the suction pad 11 holding a bag by suction.

[0057] As the suction pad 11 continues to descend, the ribs 69 are pushed upward by the reaction force from the object 29 when the suction pad 11 sucks up and deforms the bag. For example, when the bag is sucked up and deformed, the soft bag pad 57 rises slightly upward. Therefore, the bag pad 57 attempts to displace upward, but the protruding tip of the protruding portion 79 hits the cover 59, restricting further displacement. The bag pad 57, except for the inner diameter portion 77 (e.g., the protruding portion 79), is lifted and separated from the conical slope 71 of the large pad 55. Even in the state shown in FIG. 11 , there is a gap between the large pad 55 and the object 29, and the suction chamber 67 of the large pad 55 is in communication with the inner surface of the bag pad 57. In this state, the suction pad 11 has completed its suction of the object 29 (i.e., the bag), and is now able to grasp the object 29.

[0058] FIG. 12 is a cross-sectional view of a main part of the suction pad 11 gripping a bag.

[0059] When the suction pad 11 rises to grip the object 29, the weight of the object 29 causes the protruding portion 79, which is in close contact with the suction pad 11, to deform in a direction that pulls it downward. At this time, the suction pad 11 keeps at least the protruding portion 79 and rib 69 of the bag pad 57 in close contact with the bag, and grips the object 29 in a suspended state while deforming downward to follow the bag.

[0060] That is, the suction pad 11 adheres to the object 29 only by the protruding portion 79 of the bag pad 57, and the large pad 55 is not in contact with the object 29. In other words, the bag pad 57, which deforms more flexibly than the large pad 55, enables the suction pad 11 to adhere to the object 29, such as a bag. As the protruding portion 79 of the bag pad 57 hangs down while the rib 69 remains in close contact with the object 29, the large pad 55 is also pressed down by the bag pad 57 and comes into close contact with the conical slope 71 of the large pad 55. In this state, the bag pad 57 is separated from the cover 59.

[0061] Furthermore, the suction pad 11 is configured so that the cover 59 does not restrict deformation of the bag pad 57 toward the object 29. Specifically, the cover 59 does not have a portion on the inside of the cover 59 that protrudes below the bag pad 57, and the inner surface side of the bag pad 57 (i.e., the object side) does not face the bag pad 57. This allows the bag pad 57 to deform downward in response to the deformation of the object 29 when the suction pad 11 suction-holds the object 29, such as a bag, and prevents failure of suction due to air flowing in between the bag pad 57 and the object 29.

[0062] Next, the operation of the above-described configuration will be described.

[0063] The suction pad 11 according to the first embodiment includes a large pad 55 (an example of a portion of a first pad) and an annular bag pad 57 (an example of a second pad). The large pad 55 has an axis 53 aligned along a vertical axis and expands in diameter downward (an example of one end along the axis 53). The bag pad 57 is placed over the large pad 55 with an inner diameter portion 77 in contact with a small diameter upper portion 73 (an example of a small diameter portion) of the large pad 55. The bag pad 57 has a protruding portion 79 extending outward from a large diameter lower portion 75 (an example of a large diameter portion) of the large pad 55 that is located below the small diameter upper portion 73. The bag pad 57 is made of a softer material than the large pad 55. The bag pad 57 includes a plurality of ribs 69. The plurality of ribs 69 are arranged radially from the axis 53 on the underside of the protruding portion 79 (an example of an inner surface of one end) and protrude downward (an example of one end). The suction pad 11 also has a first pad. The first pad has, for example, a large pad 55 and a bellows tube 61 connected to a small-diameter upper portion 73 of the large pad 55. The first pad has a conical slope 71 (an example of a slope). The bag pad 57 has an outer shape larger than that of the first pad and covers the conical slope 71, with at least the upper portion of the bag pad 57 coming into close contact with the first pad. The bag pad 57 has multiple ribs 69 on its suction surface side (the side facing the object 29) that are closer to the periphery than the first pad.

[0064] In the suction pad 11 according to the first embodiment, the large pad 55 expands in diameter downward. Here, the suction pad 11 is oriented such that the axis 53 is aligned along the vertical axis. However, the orientation of the suction pad 11 is not limited to this. The axis 53 does not have to be aligned along the vertical direction.

[0065] When the suction pad 11 suctions the object 29, it descends from above the object 29 to reach the object 29. If the object 29 is made of a hard material such as a box, the protruding portion 79 of the descending suction pad 11 first comes into contact with the object 29. As the suction pad 11 continues to descend, the rib 69 is pushed up by the reaction force from the object 29, and the bag pad 57 moves upward away from the conical slope 71 of the large pad 55.

[0066] After the rib 69 is pushed up, the suction pad 11 is closed by the object 29 at the large-diameter lower portion 75 of the large pad 55, forming a sealed space in the suction chamber 67. Negative pressure acts on the suction chamber 67 of the large pad 55, and the suction chamber 67 approaches a vacuum due to air suction from the vacuum path 51. The large pad 55 further deforms in the direction that reduces the volume of the suction chamber 67.

[0067] When the object 29 is made of a hard material such as a box, the large pad 55 of the suction pad 11 comes into close contact with the object 29. In other words, the suction opening of the large pad 55 is blocked. In this state, the suction pad 11 has completed suctioning the object 29, and is able to grip the object 29. The ribs 69 of the bag pad 57 are pushed up by the object 29, causing the bag pad 57 to float away from the conical slope 71 of the large pad 55. The ribs 69 may also come into close contact with the object 29, reinforcing the suction force of the large pad 55.

[0068] On the other hand, if the object 29 is bag-shaped, the lower protruding end of the rib 69 of the lowered suction pad 11 first comes into contact with the object 29, as described above. As the suction pad 11 is further lowered, the bag comes into close contact with the protruding portion 79 of the bag pad 57. As the protruding portion 79 of the bag pad 57 is blocked by the bag, the suction chamber 67 of the large pad 55, which communicates with the inner surface of the bag pad 57, becomes negative pressure, and the large pad 55 deforms in a direction that reduces the volume of the suction chamber 67. The bag, attracted to the large pad 55, pushes up the rib 69. As a result, the bag pad 57, other than the inner diameter portion 77 (e.g., the protruding portion 79), floats above the conical slope 71 of the large pad 55 and separates.

[0069] In this state, the suction pad 11 has completed suctioning the object 29, and is now able to grip the object 29. When the suction pad 11 rises to grip the object 29, the weight of the object 29 causes the protruding portion 79, which is in close contact with the suction pad 11, to deform in a direction that pulls it downward. At this time, the suction pad 11 maintains a state in which at least the protruding portion 79 and rib 69 of the bag pad 57 are in close contact with the bag, and while deforming downward, is able to grip the object 29 with the object 29 suspended. In other words, the suction pad 11 is attached to the object 29 only by the protruding portion 79 of the bag pad 57, and the large pad 55 is not in contact with the object 29. In other words, the suction pad 11 is able to attach to the object 29, such as a bag, by the bag pad 57, which deforms more flexibly than the large pad 55. The bag pad 57 is in close contact with the conical slope 71 of the large pad 55 as the protruding portion 79 hangs down while the rib 69 remains in close contact with the object 29 .

[0070] Furthermore, in the suction pad 11, the bag pad 57 may be connected to the outside of the bellows tube 61 (for example, adhesive area 85), or may be connected to the large pad 55. When the bag pad 57 is connected to the outside of the bellows tube 61 (for example, adhesive area 85), the weight of the bag pad 57 is not applied very much to the large pad 55, which reduces the load on the large pad 55 and prevents a decrease in the degree of freedom of movement of the large pad 55. When the bag pad 57 is connected to the large pad 55, the weight of the bag pad 57 is not applied very much to the bellows tube 61, which reduces the load on the bellows tube 61 and prevents a decrease in the degree of freedom of movement of the bellows tube 61.

[0071] The suction pad 11 may also include a cover 59. The cover 59 may cover the bag pad 57 from above (an example of the other end side along the axis 53) and be disposed opposite the bag pad 57. The cover 59 may abut against the protruding portion 79 of the bag pad 57 displaced upward.

[0072] In this suction pad 11, the large pad 55 is provided with an annular cover 59. The cover 59 is arranged to cover and face the bag pad 57 from above. The bag pad 57 is made of a softer material than the large pad 55. Therefore, when the suction pad 11 suctions an object 29 such as a bag, if the protruding portion 79 comes into contact with a convex portion of the uneven surface of the bag, the soft protruding portion 79 may partially bounce up (turn up) due to the reaction force received from the convex portion.

[0073] When the protruding portion 79 of the suction pad 11 is turned up, the large pad 55 cannot follow the irregular unevenness of the bag, causing air leakage and making it more likely that suction will fail.

[0074] In contrast, in suction pad 11, cover 59, which covers bag pad 57 from above, is disposed opposite overhanging portion 79, so that when overhanging portion 79 attempts to displace upward, it hits cover 59. Bag pad 57 is prevented from curling up because overhanging portion 79 is pressed down from above by cover 59. This prevents suction pad 11 from failing to suction due to air leakage caused by overhanging portion 79 curling up due to unevenness on the surface of the bag.

[0075] The suction pad 11 may also include a bellows tube 61 and a reinforcing member 63. The bellows tube 61 may be connected, for example, coaxially to the small-diameter upper portion 73 of the large pad 55. The reinforcing member 63 may be located inside the connection portion where the bellows tube 61 and the reinforcing member 63 are connected, and may regulate radial inward and outward deformation of the large pad 55.

[0076] In this suction pad 11, the large pad 55 is connected coaxially to the bellows tube 61. This allows the suction pad 11 to be flexible in the direction along the axis 53 and also flexible in the direction in which the axis 53 bends.

[0077] The large pad 55 is connected to the lower narrow inclined wall 81 at the lower end of the bellows tube 61. In other words, the lower narrow inclined wall 81 serves as the connection portion. The large pad 55 has a conical slope 71 that is substantially the same as that of the upper narrow inclined wall 97. The suction pad 11 has a reinforcing member 63, which is harder than the large pad 55, that is provided in close contact with the inner circumferential surface of the lower narrow inclined wall 81, which serves as the connection portion. The reinforcing member 63 acts to restrict radial inward and outward deformation of the large pad 55.

[0078] This prevents the large pad 55 from collapsing irregularly when the suction chamber 67 is evacuated, thereby preventing air leakage and resulting in failure of suction.

[0079] In addition, the suction pad 11 may have the large pad 55 formed integrally with the bellows tube 61 .

[0080] For example, if the bellows tube 61 and the large pad 55 of the suction pad 11 are integrally molded from the same material, the number of parts can be reduced, thereby reducing material costs and manufacturing costs. In this case, the lower narrow inclined wall 81 at the lowest end of the bellows tube 61 serves as the connection part with the large pad 55. The bag pad 57 and cover 59 can be fixed to the outer peripheral surface of this lower narrow inclined wall 81, and the reinforcing member 63 can also be fixed to the inner peripheral surface. In other words, the lower narrow inclined wall 81 has four functions: a bag pad fixing part, a cover fixing part, a reinforcing member fixing part, and a connection part for the large pad 55. This allows the suction pad 11 to be configured to be high-strength and compact.

[0081] Therefore, according to the suction pad 11 of the first embodiment, even when the rib 69 is provided, it is possible to grip both the bag-shaped object 29 and the box-shaped object 29, and it is possible to prevent the size from increasing.

[0082] (Modifications) Next, modifications of the suction pad 11 according to the first embodiment will be described.

[0083] Fig. 13 is a perspective view of a modified parent-child suction pad 101 as viewed from below. Fig. 14 is a side view of the modified parent-child suction pad 101 shown in Fig. 13, with the small suction pads protruding.

[0084] The suction pad according to the present disclosure can be configured as a parent-child suction pad 101 in which a plurality of (for example, two) suction pads having the configuration shown in the first embodiment are arranged concentrically in different sizes.

[0085] The parent-child suction pad 101 includes an outer pipe 103. One end of the parent-child suction pad 101 is connected to the vacuum generator 47, and the inner pipe 121 is disposed inside the outer pipe 103. The parent-child suction pad 101 includes a ring-shaped elastic body (e.g., an O-ring) whose outer diameter closely fits the inner diameter of the outer pipe 103 and whose inner diameter closely fits the outer diameter of the inner pipe 121. The parent-child suction pad 101 includes a large suction pad fixed to the outer pipe 103. The parent-child suction pad 101 also includes a small suction pad fixed to the other end of the inner pipe 121, disposed inside the large suction pad, and movable in and out of the suction opening of the large suction pad.

[0086] Here, the large suction pad is the suction pad 11 of embodiment 1. The small suction pad is a small suction pad 105 having the same structure as the suction pad 11 but in a smaller size. The outer pipe 103 is the support pipe 49 of embodiment 1. The inner pipe 121 is a new member added to embodiment 1 and has a smaller diameter than the outer pipe 103. The parent-child suction pad 101 includes a small suction pad 105 inside the large suction pad. The small suction pad 105 has the same components as the large suction pad (i.e., suction pad 11), namely, a small pad 107, a small pouch pad 109, a small cover 111 (see FIG. 14), a small reinforcing member (not shown), and a small-diameter bellows tube 113 (see FIG. 14).

[0087] In the suction pad 11 of the first embodiment, the upper end (other end) of the support pipe 49 is fixed to the movable body 43, and the vacuum generator 47 is connected to the upper end of the support pipe 49 by a connecting tube. That is, the inner diameter side of the support pipe 49 serves as the vacuum path 51 communicating with the negative pressure port and the open-to-atmosphere port of the vacuum generator 47. In contrast, in the parent-child suction pad 101 according to the modified example, the upper end (other end) of the inner pipe 121 is fixed to the movable body 43, and the vacuum generator 47 is connected to the upper end of the inner pipe 121 by a connecting tube (not shown). That is, the inner diameter side of the inner pipe 121 serves as the vacuum path communicating with the negative pressure port and the open-to-atmosphere port of the vacuum generator 47.

[0088] The outer pipe 103 is restricted by a predetermined force (also referred to as a holding force) from moving relative to the inner pipe 121 in the direction along the axis 53 due to friction between the outer pipe 103 and an O-ring (not shown) serving as an annular elastic body and friction between the O-ring and the inner pipe 121. Therefore, if a force greater than the holding force is applied in the opposite direction, the inner pipe 121 and the outer pipe 103 can move relative to each other in the direction along the axis 53. The small suction pad 105 can move forward and backward through the suction opening of the large suction pad due to this relative movement between the inner pipe 121 and the outer pipe 103.

[0089] When the small suction pads 105 protrude from the suction openings of the large suction pads, the small suction pads 105 can suction and grip a small box-shaped object 29 and a small bag-shaped object 29. For example, the small suction pads 105 can grip plastic bottles or bags of mayonnaise or ketchup. Furthermore, when the small suction pads 105 are housed inside the large suction pads, the suction openings of the small suction pads 105 and the suction openings of the large suction pads communicate with a vacuum path. Therefore, in this case, the large suction pads can suction and grip a large box-shaped object 29 and a large bag-shaped object 29. The large box-shaped object 29 and the large bag-shaped object 29 here are the same as the objects to be gripped by the suction pad 11 in embodiment 1.

[0090] With this parent-child suction pad 101, there is no need to switch the suction pad 11 at the tip of the suction hand 13 to another size using a tool changer, and various objects 29 can be grasped while preventing the device from becoming too large.

[0091] In the parent-child suction pad 101, at least one of the cover (i.e., small cover 111) and the reinforcing member (i.e., small reinforcing member) of the small suction pad 105 may be omitted or not provided.

[0092] As described above, the parent-child suction pad 101 according to the modified example includes a small pad 107 (an example of a portion of a third pad) and a pouch pad 109 (an example of a fourth pad). The small pad 107 expands in diameter downward (an example of one end along the axis 53) with its axis 53 aligned along the vertical axis. The pouch pad 109 is placed over the small pad 107 with its inner diameter portion in contact with the small diameter upper portion (an example of a small diameter portion) of the small pad 107. The pouch pad 109 has a protruding portion that extends outward from a large diameter lower portion (an example of a large diameter portion) of the small pad 107 that is located below the small diameter upper portion. The pouch pad 109 is made of a softer material than the small pad 107. The pouch pad 109 includes a plurality of ribs. The plurality of ribs 69 are arranged radially from the axis 53 on the underside of the protruding portion 79 (an example of an inner surface at one end) and protrude downward (an example of the one end). The parent-child suction pad 101 also includes a third pad. The third pad includes, for example, a small pad 107 and a small-diameter bellows tube 113 connected to the small-diameter upper portion of the small pad 107. The third pad has a conical slope (an example of a slope). The pouch pad 109 has a larger outer diameter than the third pad, covers the conical slope, and at least the upper portion of the pouch pad 109 is in close contact with the third pad. The pouch pad 109 includes a plurality of ribs on the suction surface side (the side facing the object 29) that are closer to the outer periphery than the third pad. The inner diameter of the pouch pad 109 is smaller than that of the first pad. The small pad 107 and the pouch pad 109 are provided inside the first pad.

[0093] As a result, the parent-child suction pad 101 can be provided with a combination of a large-sized first pad and a bag pad 57, and a combination of a small-sized third pad and a small bag pad 109, and the object 29 can be adsorbed using an appropriate pad depending on the size and type of the object 29.

[0094] 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.

[0095] (Item 1) A suction pad (suction pad 11) comprising: a first pad having a slope (conical slope 71); and a second pad (bag pad 57) having an outer shape larger than that of the first pad, covering the slope, and having at least an upper portion in close contact with the first pad, wherein the second pad is formed of a material softer than that of the first pad, and has a plurality of ribs (ribs 69) on the suction surface side closer to the periphery than the first pad.

[0096] As a result, the suction pad has multiple pads (including a first pad and a second pad) for different purposes, and although it has ribs, it can adsorb both bag-shaped objects and box-shaped objects. Even in this case, it is not necessary to switch the suction pad between a pad for bags and a pad for normal use using a pad changer, and the suction pad can be prevented from becoming larger.

[0097] (Item 2) The suction pad according to Item 1, wherein the first pad has a pad main body (large pad 55) and a bellows tube (bellows tube 61) connected to a small diameter portion (small diameter upper portion 73) of the pad main body, and the second pad is connected to the outside of the bellows tube.

[0098] This allows the suction pad to include the second pad while reducing the load on the pad body.

[0099] (Item 3) The suction pad according to Item 1, wherein the first pad has a pad body and a bellows tube connected to a small diameter portion of the pad body, and the second pad is connected to the pad body.

[0100] This allows the suction pad to be provided with the second pad while reducing the load on the bellows tube.

[0101] (Item 4) The suction pad according to any one of items 1 to 3, wherein the first pad further includes a cover (cover 59) that covers the second pad from the other end (above) along the axis and is arranged opposite the second pad, and the cover abuts against the protruding portion of the second pad displaced toward the other end.

[0102] For example, when the first pad is pressed against a box to suck up an object, the second pad is likely to be turned up through the rib. In response to this, the suction pad can use the cover to hold the tip of the protruding part of the bag pad toward one end, preventing the second pad from being turned up.

[0103] (Item 5) The suction pad according to any one of items 1 to 4, wherein the first pad has a pad main body and a bellows tube connected to a small diameter portion of the pad main body, and the suction pad further includes a reinforcing member (reinforcing member 63) inside a connection portion (lower narrow inclined wall 81) where the bellows tube and the pad main body are connected, the reinforcing member restricting radial inward and outward deformation of the pad main body.

[0104] As a result, when the suction pad is used for suction, an airflow toward the other end (upward) is generated inside the bellows tube, and even if a force toward the other end or inward is generated on the side of the bellows tube, deformation of the bellows tube can be suppressed. Therefore, the suction pad can suppress air leakage during suction and failure of suction.

[0105] (Item 6) The suction pad according to any one of Items 2, 3, and 5, wherein the bellows tube and the pad body of the first pad are integrally formed.

[0106] Therefore, if the bellows tube and the large pad are integrally formed from the same material, the number of parts of the suction pad can be reduced, and material costs, manufacturing costs, etc. can be reduced.

[0107] (Item 7) The suction pad according to any one of items 1 to 6, further comprising: a third pad (small pad 107) having a slope; and a fourth pad (pad for small pouch 109) having an outer shape larger than that of the third pad, covering the slope, and having at least an upper portion in close contact with the third pad, wherein the fourth pad is formed of a material softer than that of the third pad and has a plurality of ribs on the suction surface side closer to the periphery than the third pad, and the third pad and the fourth pad are provided inside the first pad.

[0108] This allows the suction pad to be equipped with a combination of a large first pad and a large second pad, and a combination of a small third pad and a small fourth pad, and an object can be adsorbed using an appropriate pad depending on the size and type of the object.

[0109] 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.

[0110] The present disclosure is useful for suction pads and the like that can grip both bag-shaped objects and box-shaped objects and can prevent the pads from becoming too large.

[0111] REFERENCE SIGNS LIST 11 suction pad 53 axis 55 large pad 57 bag pad 59 cover 61 bellows tube 63 reinforcing member 69 rib 73 small diameter upper portion 75 large diameter lower portion 77 inner diameter portion 79 protruding portion 81 lower narrow inclined wall

Claims

1. A suction pad comprising: a first pad having a slope; and a second pad having an outer shape larger than that of the first pad, covering the slope of the first pad, and having at least an upper portion in close contact with the first pad, wherein the second pad is made of a material softer than the first pad and has a plurality of ribs arranged more peripherally than the first pad on the suction surface side.

2. The suction pad according to claim 1, wherein the first pad has a pad body and a bellows tube connected to the small diameter portion of the pad body, and the second pad is connected to the outside of the bellows tube.

3. The suction pad according to claim 1, wherein the first pad has a pad body and a bellows tube connected to the small diameter portion of the pad body, and the second pad is connected to the pad body.

4. The suction pad according to claim 1, wherein the first pad further has a cover that covers the second pad and is arranged opposite the second pad, and the cover abuts against a protruding portion of the second pad displaced toward the cover.

5. The suction pad according to claim 4, wherein the first pad further comprises a pad body and a bellows tube connected to a small diameter portion of the pad body, and the suction pad further comprises a reinforcing member on the inside of the connection portion of the bellows tube connected to the pad body, for restricting radial inward and outward deformation of the pad body.

6. The suction pad according to claim 5, wherein in said first pad, said bellows tube and said pad body are integrally formed.

7. The suction pad according to claim 1, further comprising: a third pad having a slope; and a fourth pad having an outer shape larger than that of the third pad, covering the slope of the third pad and having at least an upper portion in close contact with the third pad, the fourth pad being formed from a material softer than the third pad and having a plurality of ribs arranged more outer than the third pad on the suction surface side, and the third pad and the fourth pad being provided inside the first pad.

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