Suction pads and harvesting suction hands

Abstract

To provide an adsorption pad which can favorably adsorb even an object having an irregular shape, and in a state that reaction force is difficult to be acquired, and a harvesting adsorption hand.SOLUTION: As an adsorption part for adsorbing an object F, an adsorption pad 10 comprises an inside sponge pad 11A and an outside sponge pad 11B which is arranged at an external peripheral side rather than the inside sponge pad 11A. In the case that a side at which an adsorption face contacting with the object F exists is set as a front side when absorbing the object F, a tip of the inside sponge pad 11A and a tip of the outside sponge pad 11B are located in a same position in a fore-and-aft direction, or the tip of the inside sponge pad 11A protrudes to a front side rather than the tip of the outside sponge pad 11B. In a state of absorbing the object F, the inside sponge pad 11A is deformable or movable to a direction in which the object F is made contact with an adsorption face of the outside sponge pad 11B.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a suction pad and a suction hand for harvesting used for harvesting agricultural produce (such as fruit) from trees. [Background technology]

[0002] Patent Document 1 discloses a working hand that harvests agricultural produce by suctioning it with a vacuum pad, while Patent Document 2 discloses a suction holder that can suction and hold agricultural produce. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2-152780 [Patent Document 2] Japanese Patent Application Publication No. 11-165708 Summary of the Invention [Problem to be solved by the invention]

[0004] The working hand of Patent Document 1 uses a rubber cone-shaped pad as a suction part for suctioning agricultural products. However, such a cone-shaped pad has difficulty suctioning agricultural products with large irregular shapes. In other words, the working hand of Patent Document 1 is limited to use only for agricultural products with few irregularities on the surface and regular (close to spherical) shapes.

[0005] On the other hand, the suction holder of Patent Document 2 is said to be capable of suctioning even agricultural products with large irregular shapes. In the suction holder disclosed in Patent Document 2, the suction part that suctions the agricultural products is composed of multiple cylinders, at least the lower end of which is formed into elastic concentric circles of different diameters, and the lower ends of the multiple cylinders are formed into a bellows-type structure. By using such an suction part composed of multiple cylinders, even agricultural products with large irregular shapes can be suctioned by any of the multiple cylinders.

[0006] However, in the case of the suction holder of Patent Document 2, in order to perform suction on a case with a large suction surface, a large pressing force is required against the object to be suctioned. For this reason, it is not suitable for suctioning objects whose surfaces are soft and easily damaged, or objects that are hanging from trees and do not easily obtain a reaction force. In other words, the suction holder of Patent Document 2 can be used to suction agricultural products placed on a stand during post-harvest sorting work, but is not suitable for harvesting agricultural products that are on trees.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a suction pad and a harvesting suction hand that can effectively adsorb objects even if they have an irregular shape and are in a state where a reaction force is difficult to obtain. [Means for solving the problem]

[0008] In order to solve the above problems, the suction pad of a first aspect of the present invention is an suction pad having an suction portion for suctioning an object, the suction portion comprising an inner pad formed of a porous material and an outer pad formed of a porous material and positioned outer circumferentially of the inner pad, and characterized in that the inner pad brings the object into contact with the suction surface of the outer pad while adsorbing the object.

[0009] According to the above configuration, the object is first attracted to the inner pad, and then the object is brought into contact with the suction surface of the outer pad, so that the outer pad, which has a stronger suction force, can attract the object. Therefore, even objects such as agricultural products that are irregularly shaped and have a hard time obtaining a reaction force due to being wooden, can be attracted well.

[0010] Furthermore, when the side of the suction pad on which the suction surface that comes into contact with the object when adsorbing the object is defined as the front side, the tip of the inner pad and the tip of the outer pad can be positioned at the same position in the front-to-back direction, or the tip of the inner pad can protrude further forward than the tip of the outer pad.

[0011] According to the above-mentioned configuration, after the object is attracted by the inner pad, the object can be brought into contact with the attracting surface of the outer pad by deformation or movement of the inner pad.

[0012] In addition, in the above-mentioned suction pad, the inner pad can be made of open-cell sponge, and a vacuum suction system for adsorbing the object to the suction portion can be provided only for the inner pad.

[0013] According to the above configuration, after the object is sucked by the inner pad, the inner pad itself contracts and deforms to allow the object to come into contact with the outer pad. Furthermore, after the object is brought into contact with the outer pad, the inner pad's breathability allows the object to be sucked to the outer pad. This allows for a single vacuum suction system for sucking the object to the suction part, simplifying the configuration of the suction pad.

[0014] In the above suction pad, the outer pad may be made of a closed-cell sponge.

[0015] In addition, in the above-mentioned suction pad, the inner pad and the outer pad can be made of closed-cell sponge, and a vacuum suction system for adsorbing the object to the suction portion can be provided individually for each of the inner pad and the outer pad.

[0016] According to the above configuration, the suction force of the inner pad and the outer pad can be adjusted individually using their respective vacuum suction systems, so that the suction force for the object can be appropriately adjusted while reliably and quickly adsorbing the object.

[0017] In the above suction pad, the suction surface of the outer pad may be configured as a tapered surface that slopes downward toward the rear from the outer periphery to the inner periphery.

[0018] According to the above configuration, by making the suction surface a tapered surface, the surface pressure of the suction surface when the object is suctioned is reduced, making it difficult for suction marks to remain on the object. In addition, the device can be adapted to objects of various sizes.

[0019] The suction pad may be configured such that a bellows, which is part of a vacuum suction system for adsorbing the object to the suction portion, is connected in series to the rear of the suction portion.

[0020] According to the above configuration, when the suction portion is brought into contact with the object, the bellows makes it easier for the position and posture of the suction portion to follow the object, making it easier to suction the object.

[0021] In addition, the suction pad can be configured to have a stopper that abuts against the suction portion to limit the contraction of the bellows when the bellows is contracted with the object being adsorbed to the outer pad.

[0022] According to the above configuration, by abutting the suction part against the stopper to limit the contraction of the bellows, the suction part can be held fixed, making it easier to pluck objects such as agricultural products that have been adsorbed to the suction part from the tree.

[0023] In the above suction pad, the suction portion may have a recess that fits with a tip of the stopper when the suction portion comes into contact with the stopper.

[0024] According to the above configuration, by fitting the stopper into the recess, when an object such as agricultural produce adsorbed to the suction part is plucked from a tree, a torsional torque can be prevented from acting on the bellows, thereby suppressing damage to the bellows.

[0025] In addition, in the above-mentioned suction pad, the bellows is divided into two stages, a front bellows and a rear bellows, and the front bellows and the rear bellows are connected with a bellows holder sandwiched therebetween, and the bellows holder has its forward and backward movement guided by a linear guide, and the linear guide has the function of the stopper by abutting against the suction portion when the bellows is contracted.

[0026] According to the above configuration, when the suction part is brought into contact with the object, the front bellows can provide sufficient flexibility (following ability) to the suction part. In addition, since the bellows holder is guided by the linear guide, the entire bellows (front bellows and rear bellows) can be prevented from sagging due to gravity. In addition, after the suction part suctions the object, the rear bellows contracts to move the bellows holder backward within the linear guide, so that the linear guide can abut against the suction part and function as a stopper.

[0027] In addition, in order to solve the above problems, the second aspect of the present invention is a harvesting suction hand that is characterized by comprising the above-described suction pad, an arm to which the suction pad is attached, and a driving source that generates an adhesive force in the suction portion of the suction pad.

[0028] In addition, when the harvesting suction hand is configured such that the inner pad and the outer pad are made of a closed-cell sponge having no air permeability and a vacuum suction system is provided separately for each of the inner pad and the outer pad, the harvesting suction hand further includes a pressure control unit that adjusts the vacuum suction of the suction pad against the inner pad and the vacuum suction of the outer pad, and the pressure control unit is configured to: (a) perform vacuum suction from a first vacuum suction system corresponding to the inner pad until the pressure in the first vacuum suction system reaches a predetermined first threshold; (b) after the pressure in the first vacuum suction system reaches the first threshold, further start vacuum suction from a second vacuum suction system corresponding to the outer pad; (c) perform vacuum suction until the pressure in the first vacuum suction system and the second vacuum suction system reaches a predetermined second threshold which is a pressure lower than the first threshold; and (d) after the pressure in the first vacuum suction system and the second vacuum suction system reaches the second threshold, maintain suction by the outer pad while maintaining a rated pressure corresponding to the second threshold while taking in air into the first vacuum suction system and the second vacuum suction system.

[0029] According to the above configuration, suction by the outer pad can be maintained while maintaining the rated pressure so that an appropriate suction force can be obtained according to the object, and even objects with soft surfaces such as agricultural products (e.g., tomatoes) can be reliably and quickly adsorbed without leaving suction marks. Effect of the Invention

[0030] The suction pad and harvesting suction hand of the present invention first suctions the object with the inner pad, and then the inner pad deforms or moves to bring the object into contact with the suction surface of the outer pad and suction is performed, thereby achieving the effect of being able to effectively suction even objects such as agricultural produce that are irregularly shaped and that are like plants and therefore difficult to obtain a reaction force from. [Brief description of the drawings]

[0031] [Figure 1]1 is a perspective view of a suction pad according to a first embodiment, seen obliquely from the front. FIG. [Diagram 2] 1 is a perspective view of a suction pad according to a first embodiment, seen obliquely from behind. FIG. [Diagram 3] 3 is a cross-sectional view showing the internal structure of the suction pad according to the first embodiment. FIG. [Figure 4] FIG. 2 is a schematic diagram of a harvesting suction hand using a suction pad according to the first embodiment. [Diagram 5] 4 is a schematic cross-sectional view showing a first stage of a suction operation in the suction pad according to the first embodiment. FIG. [Figure 6] 6 is a schematic cross-sectional view showing a second stage of the suction operation of the suction pad in accordance with the first embodiment. FIG. [Figure 7] 10 is a schematic cross-sectional view showing a third stage of the suction operation of the suction pad in accordance with the first embodiment. FIG. [Figure 8] 11 is a side view showing the appearance of the suction pad according to the second embodiment. FIG. [Figure 9] 10 is a cross-sectional view showing an internal structure of the suction pad according to the second embodiment. FIG. [Figure 10] FIG. 11 is a schematic diagram of a harvesting suction hand using a suction pad according to a second embodiment. [Figure 11] 11 is a schematic cross-sectional view showing a first stage of a suction operation in the suction pad according to the second embodiment. FIG. [Figure 12] 13 is a schematic cross-sectional view showing a second stage of the suction operation of the suction pad according to the second embodiment. FIG. [Figure 13] 13 is a schematic cross-sectional view showing a third stage of the suction operation of the suction pad according to the second embodiment. FIG. [Figure 14] 13 is a schematic diagram showing the configuration of a pressure control device included in a harvesting suction hand using a suction pad according to embodiment 2. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] [First embodiment] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the configuration of an suction pad 10 according to the first embodiment will be described with reference to Figs. 1 to 3. Figs. 1 and 2 show the external appearance of the suction pad 10 according to the first embodiment, with Fig. 1 being a perspective view of the suction pad 10 seen obliquely from the front, and Fig. 2 being a perspective view of the suction pad 10 seen obliquely from the rear. Fig. 3 is a cross-sectional view showing the internal structure of the suction pad 10.

[0033] 1 to 3, the suction pad 10 is configured to include an inner sponge pad (inner pad) 11A, an outer sponge pad (outer pad) 11B, a pad holder 12, a bellows holder 13, a base plate 14, a bellows 15, a spring 16, a stopper 17, and a vacuum pipe 18. In the following description, when the suction pad 10 sucks an object F such as fruit (see FIGS. 5 to 7), the side on which the suction pad 10 has an adsorption surface that comes into contact with the object F is defined as the front side of the suction pad 10.

[0034] The inner sponge pad 11A, the outer sponge pad 11B and the pad holder 12 constitute an adsorption portion at the tip of the suction pad 10. That is, the adsorption portion of the suction pad 10 is constituted by concentrically attaching the inner sponge pad 11A and the outer sponge pad 11B, which are substantially cylindrical, to the front side of the pad holder 12, which is substantially disc-shaped.

[0035] A first opening 121 is formed in the center of the pad holder 12, and the inner sponge pad 11A is attached to the pad holder 12 so that the first opening 121 is located inside the inner circumferential surface of the inner sponge pad 11A. The outer sponge pad 11B is attached to the pad holder 12 on the outer circumferential side of the inner sponge pad 11A. The inner sponge pad 11A and the outer sponge pad 11B are arranged so that in their natural state (a state in which they are not pressed against an object F to be adsorbed, etc.), only the adsorption surface of the inner sponge pad 11A can be brought into contact with the object F. That is, the tip of the inner sponge pad 11A and the tip of the outer sponge pad 11B are located at the same position in the front-rear direction, or the tip of the inner sponge pad 11A protrudes forward from the tip of the outer sponge pad 11B.

[0036] The inner sponge pad 11A is made of a sponge material having breathability, specifically, an open-cell sponge. Furthermore, it is preferable that the inner sponge pad 11A has a suitable breathability, and here, the inner sponge pad 11A is made of a semi-open-cell sponge (i.e., semi-open-cell sponge is included in the open-cell sponge). On the other hand, the outer sponge pad 11B is made of a material that does not have breathability and is flexible. Here, the outer sponge pad 11B is made of a closed-cell sponge.

[0037] The suction surfaces formed at the tips of the inner sponge pad 11A and the outer sponge pad 11B may be flat surfaces perpendicular to the cylindrical axis, but are preferably tapered from the outer periphery to the inner periphery. If the suction surfaces are tapered, the surface pressure of the suction surfaces against the substantially spherical object F is reduced when the object F is suctioned, and suction marks are less likely to be left on the object F. In addition, the suction surfaces can be adapted to objects F of various sizes.

[0038] When the suction surface is a tapered surface, the taper angle may be the same or different between the inner sponge pad 11A and the outer sponge pad 11B. When the taper angles are different, it is preferable to make the taper angle of the outer sponge pad 11B larger than that of the inner sponge pad 11A, since the shape of the object F to be suctioned is substantially spherical. Alternatively, only the suction surface of the outer sponge pad 11B may be a tapered surface.

[0039] The bellows holder 13, base plate 14, bellows 15, spring 16, and stopper 17 can movably hold the above-mentioned suction portion when not suctioning the object F, and can fixedly hold the suction portion after suctioning the object F. In the suction pad 10, the bellows 15, spring 16, and stopper 17 are disposed between the bellows holder 13 and the base plate 14. The bellows holder 13 is disposed forward of the base plate 14.

[0040] The bellows holder 13 and the base plate 14 are both substantially disk-shaped members, and the bellows holder 13 has a second opening 131 at its center, and the base plate 14 has a third opening 141 at its center. The bellows 15 is attached between the bellows holder 13 and the base plate 14 so as to connect the second opening 131 and the third opening 141. That is, the bellows 15 is connected in series to the suction portion of the suction pad 10. The pad holder 12 is fixedly attached to the front side of the bellows holder 13, and the first opening 121 and the second opening 131 are in communication with each other. Furthermore, the vacuum pipe 18 is attached to the rear side of the base plate 14 so as to be in communication with the third opening 141. As a result, in the suction pad 10, one vacuum suction system for the inner sponge pad 11A is formed by the vacuum pipe 18, the third opening 141, the bellows 15, the second opening 131, and the first opening 121. Although the pad holder 12 and the bellows holder 13 are separate members here, they may be integrated into one member.

[0041] The springs 16 are tension springs that are disposed between the bellows holder 13 and the base plate 14, and are disposed symmetrically about a vertical line at two positions on the upper side. The springs 16 suspend the suction portion of the suction pad 10 so that it does not sag when the axis of the suction pad 10 is oriented horizontally.

[0042] The stopper 17 is provided as a protrusion that stands from the front surface of the base plate 14 toward the front side (toward the bellows holder 13). In addition, a recess 132 is formed on the rear surface of the bellows holder 13 at a position opposite to the stopper 17. The stopper 17 does not abut against the bellows holder 13 when the object F is not being attracted, but when the object F is being attracted, the tip of the stopper 17 abuts against the bellows holder 13, thereby maintaining a constant distance between the bellows holder 13 and the base plate 14. In addition, when the object F is being attracted, the tip of the stopper 17 fits into the recess 132 of the bellows holder 13, thereby restricting the movement in the circumferential direction between the bellows holder 13 and the base plate 14. It is preferable that the stopper 17 and the recess 132 are each disposed at three or more locations at equal intervals along the circumferential direction. In addition, although the configuration in which the stopper 17 is provided on the base plate 14 and the recess 132 is provided on the bellows holder 13 has been exemplified here, these may be provided in the opposite manner. That is, the stopper 17 may be provided on the bellows holder 13, and a recess into which the stopper 17 fits may be provided on the base plate 14.

[0043] The above-mentioned suction pad 10 can be used as a harvesting suction hand 1 by attaching the suction pad 10 to the tip of an arm 30 and connecting the vacuum pipe 18 to a driving source 40 via a hose 41, as shown in Fig. 4. In the harvesting suction hand 1 shown in Fig. 4, an operation button 31 is provided on the handle side of the arm 30, and the driving source 40 can be switched ON / OFF by operating the operation button 31 by the user.

[0044] The driving source 40 may be, for example, a vacuum pump. In this case, the driving source 40, which is a vacuum pump, may directly perform vacuum suction on the suction pad 10. Alternatively, the driving source 40 may be a compressor, which may be combined with an ejector to perform vacuum suction. That is, in the configuration of FIG. 4, compressed air may be sent from the driving source 40, which is a compressor, to the ejector, and vacuum suction on the suction pad 10 may be performed by the negative pressure generated by the ejector. In this case, the ejector may be disposed between the suction pad 10 and the driving source 40, or may be included in the suction pad 10 (for example, the vacuum pipe 18 may be the ejector).

[0045] Next, the suction operation of the suction pad 10 to suction the target object F will be described with reference to Figs. 5 to 7. Here, the suction operation of the suction pad 10 to suction the target object F will be described in three stages, a first stage, a second stage, and a third stage. Note that the suction operation of the suction pad 10 is performed by the suction pad 10 in a state in which it is provided on the harvesting suction hand 1, and it is necessary that the vacuum pipe 18 is connected to the drive source 40 via the hose 41. However, in Figs. 5 to 7, the hose 41 is omitted for the sake of simplicity.

[0046] FIG. 5 is a schematic cross-sectional view showing the first stage of the suction operation. In the first stage, the inner sponge pad 11A of the suction pad 10 is pressed against the object F to be suctioned. In the first stage, the drive source 40 is not driven, and vacuum suction from the vacuum pipe 18 is not performed. The object F here is, for example, an agricultural product such as fruit hanging from a tree, and does not generate a large reaction force when the suction pad 10 is pressed against it. Furthermore, although the object F is illustrated as a sphere in FIG. 5, it is also assumed that the object F is an irregularly shaped agricultural product with large projections and recesses.

[0047] 5, the inner sponge pad 11A is pressed against the object F. At this time, if the tip of the inner sponge pad 11A protrudes forward further than the tip of the outer sponge pad 11B, it becomes easy to press only the inner sponge pad 11A against the object F.

[0048] Since the diameter of the opening of the inner sponge pad 11A is small, the gap when the inner sponge pad 11A is brought close to a curved object F can be made small, and the inner sponge pad 11A can easily adhere to the object F. For this reason, the inner sponge pad 11A does not easily generate a reaction force when pressed against the object F, and the entire suction surface can be made to conform to the surface of the object F even when the object F has an irregular shape, allowing for good suction. However, the inner sponge pad 11A has a small suction surface, so its suction force (holding force for the suctioned object F) is also small, and an object F that has only been suctioned by the inner sponge pad 11A cannot be plucked from the tree by the harvesting suction hand 1 and harvested.

[0049] In the first stage, the gap between the bellows holder 13 and the base plate 14 is widened, and the stopper 17 is not in contact with the bellows holder 13. In this state, the bellows holder 13 is movably held relative to the base plate 14 by the bellows 15, and the suction portion of the suction pad 10 can swing relative to the base plate 14. This allows the position and posture of the suction portion to easily follow the object F when the suction portion is brought into contact with the object F by the bellows 15. Note that the bellows 15 allows the suction portion of the suction pad 10 to swing, but does not have enough holding force to prevent the suction portion from sagging due to gravity. Therefore, in the suction pad 10, the spring 16 prevents the suction portion from sagging.

[0050] In the second stage shown in Fig. 6, vacuum suction is performed from the vacuum pipe 18. That is, when vacuum suction is started from the first stage state, the internal space of the inner sponge pad 11A (inside the cells of the semi-open-cell sponge) is decompressed, which causes the inner sponge pad 11A itself to shrink and deform. As the inner sponge pad 11A shrinks, the attracted object F is drawn in so as to come into contact with the suction surface of the outer sponge pad 11B. In the second stage, by drawing in the object F through the contraction of the inner sponge pad 11A, it is possible to deform the entire suction surface of the outer sponge pad 11B, which has a large suction surface, so that it conforms to the surface of the object F.

[0051] After the suction surface of the outer sponge pad 11B is deformed to conform to the surface of the object F, the outer sponge pad 11B is vacuum-suctioned through the inner sponge pad 11A, and the object F can be suctioned to the outer sponge pad 11B. That is, as described above, the inner sponge pad 11A is formed of a semi-open cell sponge and has a certain degree of air permeability, so that it is possible to perform vacuum suction in the outer sponge pad 11B through the inner sponge pad 11A. As a result, in the suction pad 10 according to the first embodiment, both the suction operation for the inner sponge pad 11A and the suction operation for the outer sponge pad 11B can be performed by one vacuum suction system provided inside the inner sponge pad 11A, and the configuration of the suction pad 10 and the harvesting suction hand 1 can be simplified.

[0052] 7 shows a state where the vacuum suction is further performed from the second stage, and represents the final stage of the suction operation. That is, when the vacuum suction is further performed from the second stage, the entire vacuum suction system of the suction pad 10 is further depressurized because the outer sponge pad 11B is formed of a closed-cell sponge that has no air permeability. As a result, the bellows 15 contracts, the gap between the bellows holder 13 and the base plate 14 narrows, and the stopper 17 comes into contact with the bellows holder 13. That is, the stopper 17 restricts the contraction of the bellows 15.

[0053] In this state, the bellows holder 13 cannot swing relative to the base plate 14. At this time, the tip of the stopper 17 fits into the recess 132 of the bellows holder 13, so that the movement in the circumferential direction between the bellows holder 13 and the base plate 14 is also restricted. In this way, in the third stage, the suction part of the suction pad 10 is fixedly held relative to the base plate 14 by the contraction of the bellows 15, so that the target F sucked by the outer sponge pad 11B with a large suction force can be picked from the tree and harvested by the harvesting suction hand 1. Even if a torsional torque occurs between the bellows holder 13 and the base plate 14 due to the plucking operation at this time, this torsional torque is transmitted via the stopper 17, and the torsional torque does not act on the bellows 15 or the spring 16. In other words, damage to the bellows 15 or the spring 16 due to the torsional torque can be suppressed.

[0054] After the object F (i.e., agricultural produce such as fruit) has been harvested by the third stage suction pad 10, the vacuum suction from the vacuum piping 18 is stopped, allowing the adsorbed object F to be removed from the suction pad 10.

[0055] In the above description, the suction operation of the harvesting suction hand 1 is switched on and off by switching the drive source 40 on and off, but the present invention is not limited to this. For example, a solenoid valve may be provided midway through the hose 41, and the solenoid valve may be opened and closed while the drive source 40 is kept on to switch the suction operation on and off.

[0056] [Embodiment 2] In the suction pad 10 of the first embodiment, the inner sponge pad 11A is given a certain degree of breathability, and the vacuum suction system is unified to simplify the configuration of the suction pad 10. However, in this configuration, in order to reliably and quickly adsorb the object F, it is necessary to set the vacuum suction force from the vacuum pipe 18 to a certain degree. That is, in the suction pad 10, since the inner sponge pad 11A is given breathability, if the vacuum suction force is weak, it becomes difficult for the inner sponge pad 11A to adsorb the object F. In addition, if the breathability of the inner sponge pad 11A is reduced, the inner sponge pad 11A can adsorb the object F even if the vacuum suction force is weak. In this case, however, since the breathability of the inner sponge pad 11A is reduced, it takes a long time for the outer sponge pad 11B to adsorb the object F. The vacuum suction force from the vacuum pipe 18 can be set by the vacuum degree of the drive source 40 when the drive source 40 is a vacuum pump, or by the compression degree of the drive source 40 when the drive source 40 is a compressor.

[0057] When the vacuum suction force from the vacuum pipe 18 in the suction pad 10 is set to be strong, the final suction force also becomes large accordingly. Therefore, when the target F is an agricultural product with a soft surface (e.g., a tomato), there is a problem that suction marks are likely to remain on the target F. In the present embodiment 2, a suction pad 20 that can reliably and quickly suction the target F while appropriately adjusting the suction force for the target F will be described.

[0058] Hereinafter, the configuration of the suction pad 20 according to the present embodiment 2 will be described with reference to Fig. 8 and Fig. 9. Fig. 8 is a side view showing the appearance of the suction pad 20 according to the present embodiment 2. Fig. 9 is a cross-sectional view showing the internal structure of the suction pad 20.

[0059] 8 and 9, the suction pad 20 is configured to include an inner sponge pad (inner pad) 21A, an outer sponge pad (outer pad) 21B, an inner pad holder 22A, an outer pad holder 22B, an inner front bellows 23A, an outer front bellows 23B, an inner rear bellows 24A, an outer rear bellows 24B, a linear motion guide 25, a bellows holder 26, a base plate 27, a spring 28, an inner vacuum pipe 29A, and an outer vacuum pipe 29B. In the following description, the side on which the suction pad 20 has an adsorption surface that comes into contact with an object F (such as fruit) when the suction pad 20 adsorbs the object F is defined as the front side of the suction pad 20.

[0060] The inner sponge pad 21A, the outer sponge pad 21B, the inner pad holder 22A and the outer pad holder 22B constitute an adsorption portion at the tip of the suction pad 20. That is, in the adsorption portion of the suction pad 20, the inner sponge pad 21A and the outer sponge pad 21B are individually attached to the inner pad holder 22A and the outer pad holder 22B, respectively.

[0061] The inner sponge pad 21A and the outer sponge pad 21B are formed into a substantially cylindrical shape, and the outer sponge pad 21B is disposed on the outer circumferential side of the inner sponge pad 21A. To enable such an arrangement, the inner diameter of the outer sponge pad 21B is made larger than the outer diameter of the inner sponge pad 21A.

[0062] The inner pad holder 22A and the outer pad holder 22B are substantially disk-shaped, with the inner sponge pad 21A attached to the front side of the inner pad holder 22A, and the outer sponge pad 21B attached to the front side of the outer pad holder 22B. An inner first opening 221A is formed in the center of the inner pad holder 22A, and the inner sponge pad 21A has the inner first opening 221A arranged inside its inner circumferential surface. Similarly, an outer first opening 221B is formed in the center of the outer pad holder 22B, and the outer sponge pad 21B has the outer first opening 221B arranged inside its inner circumferential surface.

[0063] Both the inner sponge pad 21A and the outer sponge pad 21B are made of a sponge material that has no air permeability. Here, the inner sponge pad 21A and the outer sponge pad 21B are made of closed-cell sponge.

[0064] The suction surfaces formed at the tips of the inner sponge pad 21A and the outer sponge pad 21B are preferably tapered so as to descend rearward from the outer periphery to the inner periphery. When the taper angles of the inner sponge pad 21A and the outer sponge pad 21B are made different, it is preferable that the taper angle of the outer sponge pad 21B is made larger than that of the inner sponge pad 21A. Alternatively, only the suction surface of the outer sponge pad 21B may be configured to be a tapered surface. These points are the same as those of the inner sponge pad 11A and the outer sponge pad 11B in the suction pad 10.

[0065] The inner front bellows 23A, the outer front bellows 23B, the inner rear bellows 24A, the outer rear bellows 24B, the linear guide 25, the bellows holder 26, the base plate 27 and the spring 28 can movably hold the above-mentioned suction portion when the object F is not being adsorbed, and can hold it fixedly after the object F is adsorbed.

[0066] The inner front bellows 23A has a tip connected to the rear surface of the inner pad holder 22A so as to communicate with the first inner opening 221A of the inner pad holder 22A. The outer front bellows 23B has a tip connected to the rear surface of the outer pad holder 22B so as to communicate with the first outer opening 221B of the outer pad holder 22B. The rear ends of the inner front bellows 23A and the outer front bellows 23B are both connected to the front side of the bellows holder 26. The inner front bellows 23A is disposed on the inner circumferential side of the outer front bellows 23B.

[0067] In the natural state of the suction pad 20 (a state in which the suction portion is not pressed against the object F to be suctioned, etc.), the positions of the inner sponge pad 21A and the outer sponge pad 21B are determined by the lengths of the inner front bellows 23A and the outer front bellows 23B. In the natural state of the suction pad 20, the tip of the inner sponge pad 21A and the tip of the outer sponge pad 21B are at the same position in the front-to-rear direction, or the tip of the inner sponge pad 21A protrudes further forward than the tip of the outer sponge pad 21B.

[0068] The bellows holder 26 and the base plate 27 are substantially cylindrical members, and the bellows holder 26 is disposed on the front side of the base plate 27. The bellows holder 26 and the base plate 27 are connected by the inner rear bellows 24A and the outer rear bellows 24B disposed therebetween. The inner rear bellows 24A is disposed on the inner peripheral side of the outer rear bellows 24B. Furthermore, the bellows holder 26 has a recess 261 on its rear side, the recess 261 having a diameter larger than the outer diameter of the outer rear bellows 24B, and the inner rear bellows 24A and the outer rear bellows 24B are disposed inside the recess 261 with respect to the bellows holder 26.

[0069] The spring 28 is disposed between the bellows holder 26 and the base plate 27 in a space surrounded by the inner rear bellows 24A and the outer rear bellows 24B, and applies a biasing force to the bellows holder 26 in the forward direction.

[0070] The linear guide 25 is a substantially cylindrical member, the rear end of which is connected to the front surface of the base plate 27, and the bellows holder 26 is housed therein. That is, the bellows holder 26 is able to slide in the front-rear direction while being guided inside the linear guide 25. A second opening 251 having a diameter larger than the outer diameter of the outer front bellows 23B is formed in the front plate portion of the linear guide 25, and the inner front bellows 23A and the outer front bellows 23B are connected to the bellows holder 26 through the second opening 251. In addition, in the suction pad 20 in the natural state, the front surface of the bellows holder 26 abuts against the front plate portion of the linear guide 25 (the flange portion around the second opening 251) due to the biasing force of the spring 28, thereby restricting the position.

[0071] In the bellows holder 26, an inner front path 262A and an outer front path 262B are formed as paths for performing vacuum suction on the inner sponge pad 21A and the outer sponge pad 21B. The inner front path 262A is a path for communicating the inner front bellows 23A and the inner rear bellows 24A, and is formed in an area on the inner periphery side of the inner front bellows 23A and the inner rear bellows 24A. The outer front path 262B is a path for communicating the outer front bellows 23B and the outer rear bellows 24B, and is formed in an area on the outer periphery side of the inner front bellows 23A and the inner rear bellows 24A, and is formed in an area on the inner periphery side of the outer front bellows 23B and the outer rear bellows 24B. A plurality of outer front paths 262B may be provided in the bellows holder 26.

[0072] In base plate 27, an inner rear path 272A and an outer rear path 272B are formed as paths for performing spherical suction on inner sponge pad 21A and outer sponge pad 21B. Inner rear path 272A is a path for connecting inner rear bellows 24A and inner vacuum piping 29A, and is formed in an area on the inner periphery side of inner rear bellows 24A. Outer rear path 272B is a path for connecting outer rear bellows 24B and outer vacuum piping 29B, and is formed in an area on the outer periphery side of inner rear bellows 24A and in an area on the inner periphery side of outer rear bellows 24B.

[0073] The suction pad 20 according to the second embodiment has two vacuum suction systems so that suction can be controlled individually for each of the inner sponge pad 21A and the outer sponge pad 21B. That is, for the inner sponge pad 21A, a first vacuum suction system is formed by the inner vacuum piping 29A, the inner rear path 272A, the inner rear bellows 24A, the inner front path 262A, the inner front bellows 23A, and the inner first opening 221A. For the outer sponge pad 21B, a second vacuum suction system is formed by the outer vacuum piping 29B, the outer rear path 272B, the outer rear bellows 24B, the outer front path 262B, the outer front bellows 23B, and the outer first opening 221B.

[0074] The above-mentioned suction pad 20 is provided with separate vacuum suction systems (first and second vacuum suction systems) for the inner sponge pad 21A and the outer sponge pad 21B, so that the suction forces of the inner sponge pad 21A and the outer sponge pad 21 can be controlled independently. This allows the object F to be reliably and quickly suctioned while exerting an appropriate suction force on the object F when performing a suction operation on the object F. However, in order to independently control the suction forces of the inner sponge pad 21A and the outer sponge pad 21B, it is necessary to combine the suction pad 20 with a pressure control unit for adjusting the suction force.

[0075] Fig. 10 is a schematic diagram of a harvesting suction hand 2 using a suction pad 20. As shown in Fig. 10, in the harvesting suction hand 2, the suction pad 20 is attached to the tip of an arm 30, and one end of a hose 42 is attached to each of the inner vacuum pipe 29A and the outer vacuum pipe 29B of the suction pad 20. The other end of the hose 42 is connected to the output of a pressure control device 50 which serves as the above-mentioned pressure control section. The input of the pressure control device 50 is connected to the driving source 40 via a hose 41. An operation button 31 is provided on the handle side of the arm 30, and the driving source 40 is switched ON / OFF by the user operating the operation button 31.

[0076] Next, the suction operation of the suction pad 20 to suction the target object F will be described with reference to Figs. 11 to 13. Here, the suction operation of the suction pad 20 to suction the target object F will be described in three stages, first to third stages. Note that the suction operation by the suction pad 20 is performed by the suction pad 20 in a state in which it is attached to the harvesting suction hand 2, and it is necessary that the inner vacuum pipe 29A and the outer vacuum pipe 29B are connected to the pressure control device 50 via the hose 42. However, in Figs. 11 to 13, the hose 42 is omitted for the sake of simplicity.

[0077] FIG. 11 is a schematic cross-sectional view showing the first stage of the suction operation. In the first stage, the inner sponge pad 21A of the suction pad 20 is pressed against the object F to be suctioned. In the first stage, the driving source 40 is not driven, and vacuum suction is not performed from the inner vacuum pipe 29A and the outer vacuum pipe 29B. Since the diameter of the opening of the inner sponge pad 21A is small, the gap when the inner sponge pad 21A is brought close to the curved object F can be made small, and the inner sponge pad 21A can easily suction the object F. Therefore, the inner sponge pad 21A does not easily obtain a reaction force when pressed against the object F, and the entire suction surface can be made to conform to the surface of the object F even for an object F with an irregular shape, allowing good suction.

[0078] In the first stage, the bellows holder 26 is moved to the most forward position within the linear guide 25 by the biasing force of the spring 28, and therefore, neither the inner pad holder 22A nor the outer pad holder 22B contacts the linear guide 25. In this state, the inner sponge pad 21A and the outer sponge pad 21B are movably held by the inner front bellows 23A and the outer front bellows 23B, respectively, and the suction portion of the suction pad 20 can swing relative to the bellows holder 26 and the linear guide 25. This makes it easy to bring the inner sponge pad 21A into contact with the object F at an appropriate angle.

[0079] In the second stage shown in Fig. 12, only vacuum suction from the inner vacuum pipe 29A is performed. In this second stage, the entire first vacuum suction system for the inner sponge pad 21A is depressurized, which causes the inner front bellows 23A to contract. Then, as the inner front bellows 23A contracts, the inner sponge pad 21A moves, and the attracted object F is drawn in so as to come into contact with the suction surface of the outer sponge pad 21B. In the second stage, the inner sponge pad 21A moves in association with the contraction of the inner front bellows 23A to attract the object F, so that even for the outer sponge pad 21B, which has a large suction surface, the entire suction surface can be deformed to conform to the surface of the object F.

[0080] In the third stage shown in FIG. 13, vacuum suction is performed from both the inner vacuum pipe 29A and the outer vacuum pipe 29B. In this third stage, the entire vacuum suction system for both the inner sponge pad 21A and the outer sponge pad 21B is depressurized, which causes the inner front bellows 23A, the outer front bellows 23B, the inner rear bellows 24A, and the outer rear bellows 24B to all contract. As a result, the inner rear bellows 24A and the outer rear bellows 24B contract, causing the bellows holder 26 to move rearward against the biasing force of the spring 28 and come into contact with the base plate 27. In addition, the outer front bellows 23B contracts, causing the outer pad holder 22B to come into contact with the linear guide 25. That is, in the suction pad 20, the linear guide 25 functions as a stopper that limits the contraction of the outer front bellows 23B.

[0081] In this third stage, the suction portion of the suction pad 20 is fixedly held relative to the bellows holder 26 and the linear guide 25 by the contraction of the inner front bellows 23A, the outer front bellows 23B, the inner rear bellows 24A, and the outer rear bellows 24B, so that the object F sucked by the outer sponge pad 21B, which has a strong suction force, can be picked from the tree and harvested by the harvesting suction hand 2. The torsional torque generated during the plucking operation at this time does not act on the inner front bellows 23A and the outer front bellows 23B because the linear guide 25 comes into contact with the outer pad holder 22B as a stopper and receives the torsional torque due to the frictional force generated between them.

[0082] However, in order to more reliably prevent the action of torsional torque on the inner front bellows 23A and the outer front bellows 23B, unevenness may be provided on the contact surfaces of the linear guide 25 and the outer pad holder 22B, and these unevenness may be engaged to limit the circumferential displacement of the outer pad holder 22B.

[0083] After the object F (i.e., agricultural produce such as fruit) has been harvested by the third stage suction pad 20, the vacuum suction from the inner vacuum piping 29A and the outer vacuum piping 29B can be stopped, thereby allowing the adsorbed object F to be released.

[0084] In the suction pad 20 according to the second embodiment, the bellows is divided into two stages, a front bellows (inner front bellows 23A and outer front bellows 23B) and a rear bellows (inner rear bellows 24A and outer rear bellows 24B), and the front bellows and the rear bellows are connected with a bellows holder 26 sandwiched therebetween. The bellows holder 26 is guided by a linear guide 25 in its movement in the front-rear direction.

[0085] With this configuration, in the first stage described above, the front bellows can provide sufficient flexibility (following ability) at the suction portion. Also, since the bellows holder 26 is guided by the linear guide 25, sagging of the entire bellows (front and rear bellows) due to gravity can be reduced. Also, in the third stage, the rear bellows contracts to move the bellows holder 26 rearward within the linear guide 25, so that the linear guide 25 abuts against the outer pad holder 22B to function as a stopper, while also ensuring storage space for the front bellows.

[0086] In the above-mentioned suction operation of the suction pad 20, the vacuum suction to the inner vacuum pipe 29A and the outer vacuum pipe 29B is controlled by the pressure control device 50. The configuration and operation of the pressure control device 50 will be described below with reference to FIG.

[0087] As shown in Fig. 14, the pressure control device 50 includes first to third solenoid valves 51 to 53, a pressure sensor 54, and an ejector 55. In the example of Fig. 14, the driving source 40 is a compressor, and therefore the pressure control device 50 includes an ejector 55 for generating a vacuum (negative pressure) in combination with the compressor. However, when the driving source 40 is a vacuum pump, the ejector 55 can be omitted from the pressure control device 50. The pressure control device 50 also includes a control unit (microcomputer) (not shown). The control unit in the pressure control device 50 controls the opening and closing of the first to third solenoid valves 51 to 53 based on the detection result of the pressure sensor 54 and a predetermined program.

[0088] In the pressure control device 50, a first solenoid valve 51 and a pressure sensor 54 are arranged in this order from the upstream side (the side connected to the drive source 40) in a first path P1 connected to the drive source 40. In addition, in the case where the pressure control device 50 includes an ejector 55, the ejector 55 is arranged between the first solenoid valve 51 and the pressure sensor 54.

[0089] The first path P1 branches into three paths, namely, second to fourth paths P2 to P4, on the downstream side. The second path P2 is connected to the inner vacuum pipe 29A of the suction pad 20. The third path P3 is connected to the outer vacuum pipe 29B of the suction pad 20. The fourth path P4 is opened toward the atmosphere. In addition, the second solenoid valve 52 is disposed in the third path P3, and the third solenoid valve 53 is disposed in the fourth path P4.

[0090] The suction pad 20 starts its suction operation by driving the drive source 40 and opening only the first solenoid valve 51 from a state in which the first to third solenoid valves 51 to 53 are all closed. By opening the first solenoid valve 51, the suction pad 20 starts suction from the inner vacuum pipe 29A, and the target object F can be sucked onto the inner sponge pad 21A.

[0091] By suctioning the target object F to the inner sponge pad 21A, the pressure inside the first path P1 is reduced, and the pressure detected by the pressure sensor 54 also decreases. When the pressure detected by the pressure sensor 54 reaches a predetermined first threshold value Th1, the pressure control device 50 determines that the suction pad 20 has reached the second stage (the state in FIG. 12) described above, and opens the second solenoid valve 52. By opening the second solenoid valve 52, the suction pad 20 also starts suctioning from the outer vacuum pipe 29B, and the target object F can be suctioned to the outer sponge pad 21B.

[0092] When the second solenoid valve 52 is opened, the pressure detected by the pressure sensor 54 temporarily increases, but as the outer sponge pad 21B adsorbs the object F, the pressure detected by the pressure sensor 54 decreases again. When the pressure detected by the pressure sensor 54 reaches a predetermined second threshold value Th2, the pressure control device 50 determines that the suction pad 20 has reached the third stage (the state shown in FIG. 13) described above. The second threshold value Th2 is set to a higher vacuum than the first threshold value Th1.

[0093] After the pressure detected by the pressure sensor 54 reaches the second threshold value Th2, the third solenoid valve 53 is opened to continue the suction operation while taking in air from the fourth path P4. At this time, the amount of air taken in from the fourth path P4 is adjusted by controlling the opening and closing of the third solenoid valve 53 so that the pressure detected by the pressure sensor 54 is maintained at the rated pressure (corresponding to the pressure of the second threshold value Th2). This allows the suction pad 20 to maintain an optimal suction force for the target object F.

[0094] The opening and closing control of the third solenoid valve 53 may be performed by controlling the opening and closing of the third solenoid valve 53 using PWM (Pulse Width Modulation), or may be performed by using the third solenoid valve 53 as an opening adjustment valve and adjusting the opening of the third solenoid valve 53.

[0095] The embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present invention is not interpreted solely by the above-described embodiments, but is defined by the claims. Also, all modifications within the scope and meaning equivalent to the claims are included.

[0096] For example, the suction pad 10 in the first embodiment combines a configuration in which one vacuum suction system is provided (single system configuration) with a configuration in which the suction unit and the base plate 14 are connected by a single bellows (single bellows configuration). Also, the suction pad 20 in the second embodiment combines a configuration in which two vacuum suction systems are provided (two system configuration) with a configuration in which the suction unit and the base plate 27 are connected by a two bellows (two bellows configuration). However, there is no close relationship between whether the one system configuration or the two system configuration is adopted for the vacuum suction system and whether the one bellows configuration or the two bellows configuration is adopted for the bellows. That is, the suction pad of the present invention can also combine a one system configuration in the vacuum suction system with a two bellows configuration in the bellows. Similarly, it is also possible to combine a two system configuration in the vacuum suction system with a one bellows configuration in the bellows.

[0097] In the suction pads 10 and 20 described in the first and second embodiments, the inner sponge pads 11A and 21A are caused to absorb the object F, and then the inner sponge pads 11A and 21A are deformed or moved to bring the object F into contact with the suction surface of the outer sponge pads 11B and 21B. However, the present invention is not limited to this, and the object F may be caused to contact the suction surface of the outer sponge pads 11B and 21B by moving the outer sponge pads 11B and 21B forward after the object F is absorbed by the inner sponge pads 11A and 21A. [Explanation of symbols]

[0098] 1 Harvesting suction hand 10 Suction Pad 11A Inner sponge pad (suction part) (inner pad) 11B Outer sponge pad (adhesive part) (outer pad) 12 Pad holder (adsorption part) 121 First Opening 13 Bellows holder 131 Second Opening 132 Recess 14 Base plate 141 3rd Opening 15 Bellows 16 Spring 17 Stopper 18 Vacuum piping 2. Harvesting suction hand 20 Suction Pad 21A Inner sponge pad (adhesive part) (inner pad) 21B Outer sponge pad (adsorption part) (outer pad) 22A Inner pad holder (suction part) 221A Inner 1st opening 22B Outer pad holder (suction part) 221B Outside first opening 23A Inner front bellows (front bellows) 23B Outer front bellows (front bellows) 24A Inner rear bellows (rear bellows) 24B Outer rear bellows (rear bellows) 25 Linear guide 251 Second Opening 26 Bellows holder 261 Recess 262A Inner front path 262B Lateral anterior pathway 27 Base Plate 272A Medial posterior pathway 272B Lateral Posterior Pathway 28 Spring 29A Inner vacuum piping 29B Outside vacuum piping 30 Arm 31 Operation buttons 41 Hose 42 Hose 40 Power Source 50 Pressure control device (pressure control section) 51-53 1st to 3rd solenoid valves 54 Pressure Sensor 55 Ejector P1~P4 1st to 4th pathways F. Object

Claims

1. A suction pad having a suction portion for suctioning an object, the suction portion includes an inner pad formed of a porous material and an outer pad formed of a porous material and disposed on an outer circumferential side of the inner pad, After the inner pad has attracted the object, the object is brought into contact with an attracting surface of the outer pad; The inner pad is made of an open-cell sponge. A suction pad, characterized in that a vacuum suction system for suctioning the object to the suction portion is provided only for the inner pad.

2. 2. The suction pad according to claim 1, When the side on which the suction surface that comes into contact with the object when suctioning the object is defined as the front side, the tip of the inner pad and the tip of the outer pad are at the same position in the front-to-back direction, or the tip of the inner pad protrudes further forward than the tip of the outer pad.

3. 2. The suction pad according to claim 1, The suction pad is characterized in that the outer pad is made of closed-cell sponge.

4. The suction pad according to any one of claims 1 to 3, The suction pad is characterized in that the suction surface of the outer pad is a tapered surface that slopes downward toward the rear from the outer periphery to the inner periphery.

5. The suction pad according to any one of claims 1 to 4, A suction pad characterized in that a bellows, which is part of a vacuum suction system for adsorbing the object to the suction part, is connected in series to the rear of the suction part.

6. 6. The suction pad according to claim 5, A suction pad characterized in that it has a stopper that abuts against the suction portion to limit the contraction of the bellows when the bellows is contracted with the object being sucked onto the outer pad.

7. 7. The suction pad according to claim 6, The suction pad is characterized in that the suction portion has a recess that fits with a tip of the stopper when the suction portion abuts against the stopper.

8. 7. The suction pad according to claim 6, The bellows is divided into two stages, a front bellows and a rear bellows, and the front bellows and the rear bellows are connected with a bellows holder therebetween, The bellows holder is guided in its forward and backward movement by a linear guide, The suction pad is characterized in that the linear guide functions as the stopper by abutting against the suction portion when the bellows is contracted.

9. A suction pad according to any one of claims 1 to 8; an arm to which the suction pad is attached; A harvesting suction hand comprising: a drive source for generating a suction force at the suction portion of the suction pad.

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