Linear object gripping device and linear object gripping system

Abstract

To provide a linear object gripping device which is easily reduced in a size thereof and is suitable for picking up one flexible linear object.SOLUTION: A linear object gripping device 10 has: a pair of fingers 20, 31 which can grip a linear object S; a groove 24 which is formed between the pair of fingers, and in which one linear object is fitted; and suction means which sucks the linear object toward the groove. A width of an open part of the groove is larger than a diameter of the linear object in the state that the pair of fingers opened and is smaller than the diameter of the linear object in the state that the pair of fingers closed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a device for gripping and picking up a single linear object, and more particularly to a device for gripping and picking up a flexible and easily deformed linear object. [Background technology]

[0002] Robots that can autonomously grasp linear objects are becoming increasingly common. For example, Patent Document 1 discloses a method for grasping multiple flexible, shape-undefined linear objects by using a 3D camera to measure their three-dimensional shapes, and then determining whether one of the linear objects can be grasped by a robot hand without interfering with the other linear objects. However, when the number of linear objects increases to, for example, tens or hundreds, the calculation load for measuring the three-dimensional shape becomes heavy in the method described in Patent Document 1. Therefore, it may be more efficient to preliminarily select one linear object from the multiple linear objects and grasp it with a robot hand. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2019 / 098074 [Patent Document 2] Japanese Utility Model Application Publication No. 61-183327 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-082748 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 2 describes a long material supply device for copper tubes stacked on a tray, such as pipes and round bars, in which an adsorption pad connected to a vacuum pump is lowered to adsorb the copper tube midway beneath it, then raised to lift one copper tube, and a chuck grips the copper tube midway toward its tip.

[0005] However, unlike rigid pipes, flexible and easily deformed linear objects are difficult to stack in an orderly fashion, and adjacent linear objects tend to cross each other or, in extreme cases, become tangled. Therefore, when attempting to pick up such linear objects using the device described in Patent Document 2, there is a problem that when the suction pad holding the linear object is raised to lift the linear object, adjacent linear objects interfere with each other, causing the linear object to fall off the suction nozzle. Furthermore, in the device described in Patent Document 2, the suction pad and chuck are spaced apart, so in the case of flexible and easily deformed linear objects, the chuck position of the lifted linear object is unstable, making it unsuitable for secure gripping.

[0006] Patent Document 3 describes a workpiece gripping device for removing densely stacked workpieces, which uses a suction pad attached to one end of a rod-shaped portion to suck and capture a cylindrical workpiece, and moves at least two gripping claws from a retracted position on the end side of the rod-shaped portion opposite the suction pad to a gripping position where they protrude beyond the end where the suction pad is provided, toward the center plane of the rod-shaped portion, while simultaneously narrowing the distance between the gripping claws to clamp and hold the workpiece.

[0007] In the device described in Patent Document 3, gripping jaws arranged to surround the rod-shaped portion are moved along the rod-shaped portion between a retracted position and a gripping position, which is considered to make the device more compact. However, a drive unit for moving the gripping jaws toward the center plane of the rod-shaped portion and a transmission mechanism for transmitting the drive force to the gripping jaws are required, which results in a complex device structure. Furthermore, in the method described in Patent Document 3, the initial extraction of the workpiece is performed using only the suction pad. Therefore, for example, when extracting only one wire from a group of intertwined electric wires, the wires may become tangled and the workpiece may fall off the suction pad during the extraction process.

[0008] The present invention has been made in consideration of the above, and its objective is to provide a linear object gripping device that has a simpler structure than conventional technology, is easily miniaturized, and is suitable for picking up a single flexible linear object. [Means for solving the problem]

[0009] The linear object gripping device of the present invention includes a pair of fingers capable of pinching a linear object, a groove formed between the pair of fingers and into which one of the linear objects fits, and suction means for sucking the linear object toward the groove. The width of the opening of the groove is larger than the diameter of the linear object when the pair of fingers are open, and is smaller than the diameter of the linear object when the pair of fingers are closed.

[0010] Here, the open part of the groove refers to the surface facing the bottom. The open state of a pair of fingers refers to a state in which the distance between the tips of the fingers is wide. The closed state of a pair of fingers refers to a state in which the distance between the tips of the fingers is narrow, and the tips do not necessarily need to touch each other.

[0011] With this configuration, a linear object can be sucked into the groove with the fingers open, and then clamped by closing the fingers. Furthermore, since a groove is formed between the pair of fingers, it is easy to simplify the structure of the entire linear object gripping device, making it easy to miniaturize the device.

[0012] Preferably, the suction means generates an airflow from the opening of the groove toward the inside of the groove to attract the linear object, thereby making it possible to attract even a linear object that is a non-magnetic material.

[0013] Preferably, the grooves are formed at the tips of the pair of fingers, which makes it easier to suck a linear object into the grooves with the fingers spread apart.

[0014] Preferably, the pair of fingers opens and closes by rotating at least one of the fingers around a rotation axis provided on the base end side of the bottom surface of the groove as a fulcrum, thereby narrowing the gap between the pair of fingers that appears at the bottom of the groove and increasing the suction force from the open part.

[0015] Preferably, the linear object gripping device has a spring mechanism at its base end that is elastically expandable and contractible in the length direction of the finger, so that even if the linear object gripping device is pushed too far when approaching the linear object to be gripped, the spring part can contract to absorb the force acting on the tip of the finger.

[0016] The linear object gripping system of the present invention comprises any one of the linear object gripping devices described above and a storage unit for storing the linear objects. The storage unit comprises a main body and a centering means. The main body comprises two or more placement members aligned at a distance in the longitudinal direction, and places the linear objects aligned in the longitudinal direction. The centering means includes a pair of centering members arranged at both ends of at least one of the spaces, and moves the linear objects placed on the main body toward the center plane by reducing the distance between each of the centering members and a center plane that bisects the main body in the width direction. [Effects of the Invention]

[0017] According to the linear object gripping device of the present invention, a linear object can be sucked into a groove with the fingers open and then clamped by closing the fingers. This allows a single linear object to be extracted from a pile of linear objects by sucking it into the groove. Furthermore, since the fingers are closed to clamp the linear object after the linear object has fallen into the groove, even when flexible and easily deformed linear objects interfere with each other, the linear object being lifted can be picked up without falling off. Furthermore, since a groove is formed between the pair of fingers, the overall structure of the linear object gripping device can be simplified, making it easier to miniaturize the device. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a diagram showing a state in which a linear object gripping device according to an embodiment is used; [Figure 2] 3A is a side view of the linear object gripping device of the embodiment with the fingers in an open state, and FIG. 3B is a vertical cross-sectional view (cross-sectional view taken along the line XX in FIG. 3A) dividing the device in half in the width direction. [Figure 3] 1 is a front view of a linear object gripping device according to an embodiment, as viewed from the second finger side. [Figure 4] A: A side view of the tip of a linear object gripping device of one embodiment with the fingers open (enlarged view of the tip of Figure 2A), B: A view of the fingers of Figure 4A from the tip side, C: A side view of the fingers closed. [Figure 5] 5A is a plan view of a storage section for storing linear objects; FIG. 5B is a cross-sectional view (cross-sectional view taken along line BB in FIG. 5A) of the storage section for storing linear objects, in which the spacing between the centering members is widened; and FIG. 5C is a cross-sectional view of the storage section for storing linear objects, in which the spacing between the centering members is narrowed. DETAILED DESCRIPTION OF THE INVENTION

[0019] An embodiment of a linear object gripping device according to the present invention will be described with reference to the drawings.

[0020] Referring to FIG. 1, a large number of flexible linear objects S are placed in a tray-like storage unit 50 with their lengths aligned. A linear object gripping device 10 is disposed above the linear objects S with its tip pointing downward. The linear object gripping device 10 is movable up and down, and can lower itself to grip one of the linear objects S by suction and clamping it, and then rise again to lift the gripped linear object. The linear object gripping device 10 is used by being attached to the tip of, for example, a linear actuator or a robot arm. Note that hereinafter, the linear object gripping device 10 may be simply referred to as the device 10.

[0021] While the type of linear object S is not particularly limited, the linear object gripping device 10 of this embodiment is easily miniaturized and has the advantage of being able to pick up a single linear object even from among adjacent intersecting or entangled linear objects, providing significant advantages when targeting thin and flexible linear objects. For this reason, the diameter of the linear object S is preferably 10 mm or less, more preferably 5 mm or less, and even more preferably 1 mm or less. On the other hand, for ease of processing and manufacturing the device 10, the diameter of the linear object is preferably 0.05 mm or more, more preferably 0.1 mm or more. Furthermore, it is preferable that the linear object S is flexible and easily deformed. Examples of linear objects S targeted by the linear object gripping device 10 include electric wires used in wiring electrical and electronic devices, optical fiber cables, medical devices and the resin tubes and metal wires used as materials for such devices, and plant materials such as flower stems.

[0022] 2 to 4, the linear object gripping device 10 has a first finger 20 and a second finger 31. Both the first finger and the second finger are plate-shaped or rectangular prism-shaped and are arranged with one surface facing closely. The first finger and the second finger are formed into a wedge shape by providing inclined surfaces 23 and 33 at the tip of the surface opposite the other fingers so that the thickness decreases toward the tip 22 and 32. Note that, hereinafter, with respect to the first finger and the second finger, the up-down direction in FIGS. 2 and 3 will be referred to as the length direction of the finger, the left-right direction in FIG. 3 will be referred to as the width direction of the finger, and the left-right direction in FIG. 2 will be referred to as the thickness direction of the finger. Also, the surface facing the other finger will be referred to as the facing surface, the surface opposite the facing surface will be referred to as the back surface, and both end surfaces in the width direction will be referred to as side surfaces. Also, the first finger and the second finger together will be simply referred to as fingers 20 and 31.

[0023] The first finger 20 is fixed to a rectangular first support plate 11 so that the length direction of the finger is perpendicular to the first support plate. The first finger 20 is fixed to the first support plate using fixing devices such as bolts 17 at fixing portions 21 protruding from the side or back of the first support plate. The second finger 31 is connected to the first finger 20 via a rotation shaft 34, which will be described later. The first support plate is connected to a third support plate 13, which is also rectangular and parallel to the first support plate, using guide pins 14 and coil springs 16, which will be described later. The third support plate 13 is attached to the tip of a robot arm or the like by an appropriate fixing means.

[0024] The opposing surface of the first finger 20 has a notch cut out across the entire width of its tip, forming a groove 24 that is long in the width direction of the fingers along the tips 22, 32 of the first finger 20 and the second finger 31, between the first finger and the second finger. The notched portion of the first finger forms one side wall surface with the bottom surface 25 of the groove 24, and the second finger forms the other side wall surface, leaving a gap 26 between the two fingers at the bottom surface 25. Both ends of the groove 24 in the length direction are open to the side surfaces of the first finger 20. A long, narrow open portion 27 is formed between the tip 22 of the first finger and the tip 32 of the second finger at the portion of the groove 24 that faces the bottom surface 25.

[0025] A substantially rectangular suction port 28 is formed in the bottom surface 25 of the groove 24. The suction port 28 is connected to a vacuum source (not shown) through a suction hole 29 inside the first finger 20 and a suction tube 30 extending from the back surface at the base end side of the first finger. By sucking air through this suction port 28, an airflow is generated from the opening 27 of the groove 24 toward the inside of the groove 24, and linear object S near the opening 27 is sucked toward the groove.

[0026] The suction means for attracting the linear object S toward the groove 24 may be a magnetic attraction means, but it is preferable to use the airflow shown in this embodiment. This is because it is possible to attract linear objects even if they are non-magnetic, and if the linear objects are magnetic, many linear objects will not be attracted to a magnet or the like in a line.

[0027] The width of the groove 24 is set to a size that fits one linear object S but not two or more linear objects S, depending on the diameter of the linear object S. Specifically, the width of the groove 24 is more than 1 time but less than 2 times the diameter of the linear object, preferably 1.1 to 1.8 times, and more preferably 1.2 to 1.5 times.

[0028] The depth of groove 24 is more than 0.5 times the diameter of the linear object S so that the linear object can be held when the fingers are closed with one of the linear objects S fitted in the groove, and is set to a depth that prevents two linear objects from fitting in the groove depending on the width of the groove. The depth of groove 24 is preferably 0.8 to 1.5 times, and more preferably 1.0 to 1.2 times, the diameter of the linear object, provided that two linear objects cannot fit in the groove.

[0029] If the length of groove 24 is too short, a larger proportion of the airflow will flow from both ends of groove 24 into the groove rather than from open portion 27, weakening the force that sucks the linear object into the groove from open portion 27. For this reason, the length of groove 24 is preferably at least three times, and more preferably at least five times, the diameter of linear object S. On the other hand, if groove 24 is too long and linear object S is flexible and easily deformed, the deformed linear object may get caught on the tip of first finger 22 or the tip of second finger 32, preventing the linear object from fitting into groove 24. For this reason, the length of groove 24 is preferably at most 20 times, and more preferably at most 10 times, the diameter of the linear object.

[0030] It is preferable that the width of the gap 26 between the first finger 20 and the second finger 31 that appears at the bottom surface 25 of the groove 24 is narrow. If the width of the gap 26 is too wide, the amount of air that passes through the gap 26 and flows into the groove interior increases, weakening the suction force that sucks the linear object S from the open portion 27 toward the groove 24. The width of the gap 26 is preferably 1 / 2 or less, and more preferably 1 / 4 or less, of the width of the open portion 27 when the fingers 20, 31 are in an open state.

[0031] In Figures 2 to 4, the groove 24 is formed by cutting out the tip of the first finger 20, but this is not limited to this. The groove may be formed by cutting out the tip of the second finger 31, or the groove may be formed by cutting out the tips of both the first and second fingers.

[0032] 2 to 4, suction ports 28 are provided on the bottom surface 25 of groove 24, but suction ports may also be provided on the side wall surfaces of groove 24. Furthermore, when groove 24 is formed by cutting out first finger 20, suction ports may also be provided near bottom surface 25 of groove 24 on the surface facing second finger 31 that is not cut out.

[0033] The second finger 31 is connected to the first finger 20 via a rotation shaft 34 located on the base end side of the bottom surface 25 of the groove 24. The rotation shaft 34 passes through a bearing hole 36 provided in the second finger and is supported by two bearing portions 35 protruding from both ends of the first finger in the width direction toward the opposing surface. An actuator 37 is fixed to the second support plate 12 erected on the base end side of the first support plate 11, and the tip of the piston rod of the actuator 37 is connected to a link 38 at the base end of the second finger. With this structure, by extending or retracting the actuator 37, the second finger 31 rotates around the rotation shaft 34 as a fulcrum, opening and closing the finger.

[0034] The state in which the fingers 20 and 31 are open refers to a state in which the distance between the finger tips 22 and 32 is wide. The state in which the fingers 20 and 31 are closed refers to a state in which the distance between the finger tips 22 and 32 is narrow, and the tip 22 of the first finger and the tip 32 of the second finger do not necessarily have to be in contact. In Figure 4, Figures 4A and 4B show the open state of the fingers, and Figure 4C shows the closed state of the fingers.

[0035] The rotation axis 34 is preferably located close to the bottom surface 25 of the groove 24. As mentioned earlier, the narrower the gap 26 that appears at the bottom surface 25 of the groove, the more preferable it is. This is because the closer the distance between the rotation axis and the bottom surface, the greater the ratio of the change in the distance between the tip 22 and the tip 32 of the first finger to the width of the gap can be.

[0036] In this embodiment, the fingers are opened and closed by fixing the first finger 20 and rotating the second finger 31, but this is not limited thereto, and both the first and second fingers may be rotated. Furthermore, the combination of fingers that are fixed or rotatable, fingers with notched tips, and fingers with suction ports 28 is not particularly limited and can be freely determined.

[0037] The linear object gripping device 10 is provided at its base end with a spring mechanism that can elastically expand and contract in the length direction of the fingers 20 and 31. The spring mechanism includes a first support plate 11, a third support plate 13, a guide pin 14, and a coil spring 16. As described above, the first finger 20 is directly fixed to the first support plate 11, and the second finger 31 is indirectly fixed via the first finger. The first support plate is connected to the third support plate 13, which is also rectangular and parallel to the first support plate, using the guide pin 14 and the coil spring 16. Two guide pins 14 are provided to connect two ends of the first support plate and the third support plate. The number of guide pins is not limited to two and may be three or four. One end of each guide pin is fixed to the third support plate by a screw or the like, and the other end is inserted into a guide hole 15 that penetrates the first support plate in the thickness direction. The guide pin 14 is inserted into a coil spring 16, and both ends of the coil spring are fixed to a first support plate or a third support plate, respectively. The third support plate is fixed to the tip of a robot arm or the like.

[0038] When the fingers 20, 31 are pushed toward the base end with the linear object gripping device 10 attached to the tip of a robot arm or the like, the coil spring 16 sandwiched between the first support plate 11 and the third support plate 13 contracts, and the guide pin 14 passes through the guide hole 15 and protrudes toward the tip end of the first support plate. When the force pushing the fingers toward the base end is released, the coil spring expands to its original state.

[0039] By providing the linear object gripping device 10 with a spring mechanism, even if the device 10 is pushed too far when approaching the linear object S to be gripped, the spring mechanism contracts and absorbs the force applied to the tips of the fingers 20, 31. This simplifies control of the movement of the device 10 when approaching a pile of linear objects from above and picking up the linear objects one by one, since there is no need to change the distance by which the device 10 is lowered depending on the height of the pile of linear objects.

[0040] The spring mechanism is not limited to the coil spring 16 as long as it can expand and contract elastically, and can be realized using various elastic means such as a leaf spring or an air spring.

[0041] Referring to FIG. 5, the storage section 50 has a main body section 51 on which linear objects S are placed, and a centering means for bringing the placed linear objects to a center plane Z that divides the main body section in half in the width direction.

[0042] The main body 51 is generally rectangular and plate-like in plan view. The main body 51 is made up of three mounting members 52 aligned at intervals in the longitudinal direction. Each mounting member has a mounting surface 53 on which the linear object S is placed and edges 54 extending from both sides of the mounting surface, and has a shallow U-shaped cross section.

[0043] In the gap 55 between the mounting members 52, a pair of plate-shaped centering members 56 are arranged on both sides of the gap 55, sandwiching the main body 51 between them. The centering members 56 on the same side of the main body 51 are fixed to a common support plate 58 via support rods 57, and the support plate 58 is connected to a piston rod 60 of an actuator 59. The centering members 56, support rods 57, support plate 58, and actuator 59 are arranged symmetrically with the main body 51 in between, and together constitute the centering means of this embodiment.

[0044] The centering means can change the distance between the centering member 56 and the central plane Z by operating the actuator 59. When the centering member 56 is away from the central plane Z (FIGS. 5A and 5B), the centering member 56 is pushed into the gap 55 to move closer to the central plane Z, thereby moving the linear object S on the main body toward the central plane Z (FIG. 5C). Note that in FIGS. 5B and 5C, only the end surface of the linear object S is shown.

[0045] To provide a centering means, the number of mounting members 52 constituting the main body 51 needs to be two or more and there needs to be one or more gaps 55, but preferably the number of mounting members 52 needs to be three or more and there should be two or more gaps 55. This is because the linear objects S can be more densely packed near the center plane Z in the area sandwiched between the two gaps.

[0046] Next, a method of using the linear object gripping device 10 of this embodiment will be described.

[0047] A plurality of linear objects S are stored in the storage section 50. The linear object gripping device 10 is positioned above the central plane Z with the groove 24 approximately parallel to the central plane Z. With the fingers 20 and 31 open, the device is lowered while sucking air through the suction port 28. As the fingertips 22 and 32 approach the linear object S, nearby linear objects are sucked toward the groove 24, and one linear object fits into the groove 24. If the device 10 were lowered at a constant distance, for example, always close to the storage section's mounting surface 53, the fingertips 22 and 32 would abut against the pile of linear objects before reaching the bottom end of the descent, and the device 10 would continue to push the linear objects downward. However, the spring mechanism compresses, absorbing the force applied to the device 10, preventing damage to the fingers 20 and 31 and other parts. The fingers 20 and 31 are closed to clamp the single linear object S fitted in the groove 24, and the device 10 is then raised. This completes the picking up of one linear object.

[0048] When the work of taking up the linear objects S continues and the number of linear objects on the storage section 50 decreases, the centering member 56 is pushed out toward the center plane Z to gather the linear objects closer to the center plane Z, and the work of taking up can be continued further.

[0049] The linear object gripping device of this embodiment is suitable for picking up one linear object from among a large number of linear objects, but can also be used to pick up a single supplied linear object.

[0050] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the technical concept thereof. [Explanation of symbols]

[0051] 10 Linear object gripping device 11 1st support plate 12 second support plate; 13 third support plate 14 Guide pin 15 Guide hole 16 Coil spring 17 volts 20 1st finger 21 Fixed part 22 1st finger tip: 23 Inclined surface 24 groove 25 Bottom of groove 26 Gaps appearing at the bottom of the groove 27 Groove opening 28 Suction port 29 Suction hole 30 Suction tube 31 2nd finger 32 2nd finger tip 33 Slope 34 Rotation axis 35 Bearing section 36 Bearing hole 37 Actuator 38 Links 50 Storage section 51 Main body 52 Mounting member 53 Placement surface 54 En 55 Cavity 56 Centering member 57 Center support rod 58 Center support plate 59 Actuator 60 Piston rod S linear object Z Center plane of the housing body

Claims

1. A pair of fingers capable of holding a linear object; a groove formed between the pair of fingers and into which one of the linear objects is fitted; a suction means for sucking the linear object toward the groove, the suction means generates an airflow from an opening of the groove toward the inside of the groove by a suction port formed in at least one of the pair of fingers, thereby sucking the linear object into the inside of the groove; a width of the opening of the groove is larger than a diameter of the linear object when the pair of fingers are in an open state, and is smaller than a diameter of the linear object when the pair of fingers are in a closed state; Linear object gripping device.

2. The bottom surface and both side wall surfaces of the groove are formed by the pair of fingers, the suction means has the suction port provided on the bottom surface or the side wall surface of the groove; The linear object gripping device according to claim 1 .

3. The grooves are formed at the tips of the pair of fingers. The linear object gripping device according to claim 1 or 2.

4. The pair of fingers opens and closes when at least one of the fingers rotates around a rotation axis provided on the base end side of the bottom surface of the groove as a fulcrum. The linear object gripping device according to claim 1 .

5. The linear object gripping device has a spring mechanism at its base end that is elastically expandable and contractible in the length direction of the fingers. The linear object gripping device according to any one of claims 1 to 4.

6. A linear object gripping device according to any one of claims 1 to 5, and a storage unit that stores the linear object, The storage section is a main body portion on which the linear objects aligned in the length direction are placed; a member for gathering the linear objects placed on the main body in a width direction and packing them closely together, Linear object gripping system.

7. A linear object gripping device according to any one of claims 1 to 5, and a storage unit that stores the linear object, The storage section is a main body portion that includes two or more mounting members aligned at intervals in the length direction and on which the linear objects aligned in the length direction are placed; a centering means for moving the linear object placed on the main body toward the center plane by shortening the distance between each of the centering members and a center plane that divides the main body in half in the width direction, the centering means being provided with a pair of centering members arranged at both ends of at least one of the intervals; Linear object gripping system.

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