Linear object pick-up hand and linear object pick-up method

Abstract

To provide a linear object pick-up hand which achieves low processing costs of members and enables easy exchange.SOLUTION: A linear object pick-up hand 10 is used to pick up one linear object from a bundle of the linear objects C and has a hook member 20 and a pressing member 30. The apical part of the hook member has a rod-like shape, includes an inlet, into which the linear object may enter, at the side around the apical part, and further includes a recessed part having a size such that the one linear object is fitted. The apical part of the pressing member has a rod-like shape, provided with a groove formed in a longitudinal direction and having a C shaped cross section, and comprises a side surface part forming the side wall of the groove, and a bottom surface part forming the bottom of the groove and including a lid part extending longer than the side surface part at the apical part. The hook member and the pressing member are fitted with each other and may slide in a longitudinal direction relative to each other.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an apparatus and method for picking up linear objects, and more particularly to an apparatus and method suitable for picking up a single linear object from a bundle of thin, flexible linear objects. [Background technology]

[0002] In various tasks involving thin, flexible, and easily deformable linear objects, robots are being used to automate the handling of the linear objects. For example, when performing tasks such as crimping terminals, mounting connectors and other parts, soldering, welding, and connecting cables such as electric wires, optical fibers, and various tubes, the linear objects to be worked on are grasped by a robot hand and transported to and set in a target processing device or inspection device.

[0003] At this time, the robot hand must first grasp one linear object from among a plurality of linear objects supplied from a supply tray or the like. Patent Document 1 discloses a method for measuring the three-dimensional shapes of a plurality of flexible and shape-undefined linear objects, determining whether one of the linear objects can be grasped by the robot hand without interfering with the other linear objects, and grasping the linear object. 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, so that it may be more efficient to extract one linear object from the many linear objects in advance and grasp the extracted linear object with the robot hand.

[0004] In response to this, Patent Document 2 describes a linear object gripping device that has a pair of fingers capable of pinching linear objects, a groove formed between the pair of fingers into which one linear object fits, and suction means for sucking the linear object toward the groove, and is suitable for picking up one linear object from among many flexible linear objects. The single linear object picked up by this linear object gripping device can be gripped by another robot hand without three-dimensional measurement. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 098074 [Patent Document 2] JP 2023-090089 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the linear object gripping device described in Patent Document 2 has a problem when many types of linear objects are handled. The size of the groove into which the linear object fits is optimized according to the diameter of the linear object, so the fingers need to be replaced when the diameter of the linear object changes. In the device of Patent Document 2, advanced processing is required to form a suction hole inside one of the fingers to perform vacuum suction, and the processing cost of the fingers to be aligned according to the diameter of the linear object is high, and the finger replacement work is also time-consuming. In addition, in order to lower the linear object gripping device from above to a predetermined position to grip the linear object, a means (centering means) is required to move the linear object placed in the storage section toward directly below the finger, and when the linear objects are supplied in separate trays for different colors, for example, there is also a problem that the installation space of the device becomes large due to the centering means provided for each tray.

[0007] The present invention has been made in consideration of the above, and aims to provide a linear object pick-up hand in which the shape of the member for gripping the linear object is simple, the processing cost is low, and it is easy to replace. It also aims to provide a linear object pick-up hand that can keep the installation space small even when the linear objects are supplied in multiple trays. [Means for solving the problem]

[0008] The linear object pick-up hand of the present invention is a hand for picking up one linear object from a bundle of linear objects, and includes a hook member and a pressing member. The tip of the hook member is rod-shaped, and has an entrance through which the linear object can enter formed on the side near the tip, and a recess of a size for one of the linear objects to fit into. The tip of the pressing member is rod-shaped with a U-shaped cross section and a groove formed in the longitudinal direction, and includes a side portion constituting the side wall of the groove, and a bottom surface portion constituting the bottom of the groove and having a lid portion extending longer than the side portion at the tip. The hook member and the pressing member are fitted with the pressing member so that the hook member fits into the groove with the entrance facing the bottom surface portion, and are relatively slidable in the longitudinal direction at least between a position where the lid portion closes the entrance and a position where the lid portion is located closer to the base end of the hook member than the entrance and opens the entrance.

[0009] Here, the inlet is an inlet for a linear object that is approximately perpendicular to the hook member to enter the recess. With this configuration, even when the hook member is replaced depending on the diameter of the linear object, the processing cost of the hook member is low and the replacement work is easy.

[0010] In the linear object pick-up hand, the hook member and the pressing member are preferably relatively slidable in the longitudinal direction at least between a position where the lid portion closes the entrance and the front end of the side portion can press the linear object that is fitted in the recess toward the tip end of the hook member, and a position where the lid portion is located closer to the base end of the hook member than the entrance and opens the entrance. This prevents the linear object from slipping in the longitudinal direction and falling out of the recess when the linear object is gripped and lifted by the linear object pick-up hand.

[0011] In any of the linear object pick-up hands described above, a jaw portion formed between the tip of the hook member and the recess may be formed in a wedge shape so that the recess becomes wider toward the entrance, making it easier for the linear object to fit into the recess.

[0012] Preferably, any of the linear object picking hands described above further includes a sensor for detecting the longitudinal positional relationship between the hook member and the pressing member. By detecting the longitudinal positional relationship between the hook member and the pressing member when the lid closes the entrance, the presence or absence of a linear object in the recess can be detected, and thus the success or failure of gripping can be detected.

[0013] The linear object pick-up method of the present invention is a method of picking up linear objects using any of the linear object pick-up hands described above, and includes the steps of placing the bundle of linear objects approximately parallel to a loading surface having a wall on one side, pressing the linear object pick-up hand against the bundle of linear objects from the opposite side to the wall toward the wall with the entrance open, thereby fitting one of the linear objects into the recess, moving the hook member and / or the pressing member in the longitudinal direction to block the entrance with the lid portion, and raising the entire linear object pick-up hand. Effect of the Invention

[0014] According to the linear object pick-up hand of the present invention, when picking up linear objects of different diameters, it is only necessary to replace the hook member, which has a simple structure and low processing costs, and since vacuum suction is not performed, the connection structure of the hook member is simple and easy to replace. Furthermore, according to the linear object pick-up hand of the present invention, as in the linear object pick-up method of the present invention, a bundle of linear objects can be pressed against a wall with the linear object pick-up hand to grasp each linear object, so there is no need to provide a separate means for collecting the linear objects in the bundle at a predetermined position. This makes it possible to keep the installation space of the entire system small, even when the linear objects are supplied in multiple trays. [Brief description of the drawings]

[0015] [Figure 1] 1A is a plan view of a hook member, B is a side view of the hook member, C is a plan view of a pressing member, and D is a side view of the pressing member, showing the shapes of main members of a linear object picking hand according to an embodiment of the present invention; [Diagram 2] 1A and 1B are diagrams showing a linear object pick-up hand according to an embodiment of the present invention, in which A shows a state in which a linear object is fitted into a hook member recess, and B shows a state in which the linear object is gripped. [Diagram 3] 1A and 1B are diagrams for explaining a method for detecting whether a linear object has been gripped or not, A being a side view and B being a cross-sectional view taken along the line XX of A. [Figure 4] 1 is a diagram showing the positional relationship between a linear object pick-up hand and a linear object supply tray in one embodiment; [Diagram 5] 5A to 5D are diagrams for explaining a linear object pick-up method according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] A linear object pick-up hand according to one embodiment of the present invention will be described with reference to Figures 1 to 4. The linear object pick-up hand 10 of the present invention has a hook member 20 and a pressing member 30, and as shown in Figure 4, grips and picks up one linear object from a bundle of linear objects C stacked on a supply tray 60. In the following, the lower side of Figures 1 to 4 will be referred to as the tip side of the linear object pick-up hand and each member, and the upper side will be referred to as the base side.

[0017] The linear object picked up by the linear object picking hand 10 is a flexible thin wire. The diameter of the linear object is 0.2 to 5.0 mm, preferably 0.5 to 3.0 mm. Moreover, linear objects with a relatively soft surface are suitable for picking up by the linear object picking hand of this embodiment. Examples of linear objects include metal wires coated with resin and those made entirely of resin, such as electric wires used in wiring and wire harnesses for electrical appliances, optical fibers, and resin tubes used in medical devices such as catheters.

[0018] 1A and 1B, the hook member 20 is rod-shaped with a rectangular cross section. The hook member has a recess 21 with an inlet 22 formed on the side near the tip. The inlet 22 is an inlet for a linear object C that is approximately perpendicular to the hook member 20 to enter the recess 21. The material of the hook member is preferably a hard resin or a metal such as stainless steel (SUS303, SUS304, etc.).

[0019] The size of the recess 21 is large enough to fit one linear object, but large enough not to fit two linear objects. The shape of the recess is not particularly limited. The shape of the recess in this embodiment is a rectangle with an approximately semicircular back (left side of FIG. 2B) in side view of FIG. 2B. It is preferable that the back of the recess is approximately semicircular in side view, because the position of the fitted linear object is easily stabilized. In this case, the diameter of the approximately semicircular circle is preferably 1.01 to 1.07 times the diameter of the linear object to be removed.

[0020] The size of the entrance 22 of the recess 21 is preferably such that the height Hd in the longitudinal direction of the hook member 20 is 1.01 to 1.15 times the diameter of the linear object to be picked up. This is because within this range, one linear object can easily enter the recess, but two linear objects cannot enter.

[0021] The width Wh of the hook member 20 as viewed from the entrance 22 side is preferably 1 mm or more in order to ensure the necessary strength. On the other hand, the width Wh is preferably no more than twice the diameter of the linear object to be picked up. This is because a narrower width Wh makes it easier for the linear object to enter the recess 21 even if it is curved and the part of the linear object facing the entrance 22 is not horizontal but inclined.

[0022] The thickness Th of the hook member 20 at the innermost part of the recess 21 is preferably 1 mm or more in order to ensure the necessary strength. On the other hand, the thickness Th is preferably 5 mm or less because there is no particular advantage to having a thickness greater than this.

[0023] The jaw portion 23 formed between the tip of the hook member 20 and the recess 21 may be formed in a wedge shape so that the recess 21 becomes wider from the back toward the entrance 22. This makes it easier for the linear object C to fit into the recess 21.

[0024] A cutout portion 24 is formed near the base end of the hook member 20. The cutout portion 24 is used to detect whether or not the hook member has been successfully gripped. The function of the cutout portion will be described later. A fixing hole 28 is provided at the base end of the hook member for fixing the hook member to a first base member, which will be described later. Note that although the hook member 20 of this embodiment is entirely rod-shaped, the base end side of the hook member does not necessarily have to be rod-shaped.

[0025] 1C and 1D, the tip of the pressing member 30 is rod-shaped with a U-shaped cross section in which a groove 31 is formed in the longitudinal direction, and is made up of a bottom surface portion 32 constituting the bottom of the groove 31 and a side surface portion 34 constituting the side wall of the groove 31. The tip of the bottom surface portion 32 extends longer than the side surface portion 34 to form a lid portion 33. The tip end of the side surface portion, i.e., a front end 35, prevents the linear object C fitted in the recess 21 of the hook member 20 from tilting from the horizontal, or preferably presses it toward the tip. Details will be described later.

[0026] A fixing portion 36 is formed at the base end of the pressing member so as to protrude laterally, and a fixing hole 38 is provided in the fixing portion for fixing to a second base member described below. The pressing member is preferably made of a hard resin or a metal such as stainless steel (SUS303, SUS304, etc.).

[0027] The width Ws of the pressing member 30 as viewed from the bottom side is preferably 2 mm or more, more preferably 3 mm or more, provided that the hook member 20 can fit into the groove 31, and in the case where the diameter of the linear object to be picked up is 0.2 to 5.0 mm, preferably 0.5 to 3.0 mm. This is to ensure the necessary strength. On the other hand, the width Ws is preferably 9 mm or less, more preferably 7 mm or less. If the width Ws is too wide, it becomes more difficult to pick up a single linear object when the parallelism of the linear object to be picked up is disturbed.

[0028] Referring to FIG. 2A, the hook member 20 has a base end fixed to a first base member 40. A pair of fixing plates 42 are erected on the upper surface of the first base member so as to sandwich the base end of the hook member. The base end of the hook member passes through a hook member through hole 41 formed in the first base member, and a bolt 48 is passed through the fixing plate 42 and the fixing hole 28, and is fastened to a nut on the opposite side (not shown), thereby fixing the hook member to the first base member. An actuator 51 is fixed to the upper surface of the first base member, and a rod 52 of the actuator extends downward through a rod through hole 43 formed in the first base member. The first base member can be reciprocated in the up and down direction of FIG. 2A by a lifting means (not shown).

[0029] The base end of the pressing member 30 is fixed to the second base member 50. The pressing member is fixed to the second base member by passing a bolt 58 through a fixing hole 38 of a fixing portion 36 of the pressing member and fastening it to a nut 59 on the upper surface of the second base member. An optical sensor 54 is provided on the upper surface of the second base member. The optical sensor 54 will be described later. The second base member 50 is supported by the actuator 51 by being fixed to the tip of a rod 52 of the actuator 51 by a fixing portion 53. By expanding and contracting the actuator 51, the second base member can reciprocate in the up and down directions in FIG. 2A relative to the first base member.

[0030] 2A and 1, the hook member 20 and the pressing member 30 are fitted to the pressing member 30 at the tip such that the hook member fits into the groove 31 with the inlet 22 facing the bottom surface portion 32. The hook member 20 fixed to the first base member 40 and the pressing member 30 fixed to the second base member 50 can slide relatively in the longitudinal direction by the expansion and contraction of the actuator 51. Note that, in the side view of FIG. 2A, the overall thickness D when the hook member 20 and the pressing member 30 are fitted to each other is preferably about 2.0 to 9.0 mm when the diameter of the linear object to be picked up is 0.2 to 5.0 mm, preferably 0.5 to 3.0 mm.

[0031] 2A, the pressing member 30 is at the upper end position of sliding relative to the hook member 20. At this time, the cover portion 33 of the pressing member 30 is located on the base end side of the inlet 22 of the hook member 20, the inlet 22 is open, and the linear object C that is approximately perpendicular to the hook member 20 can fit into the recess 21.

[0032] In Fig. 2B, the pressing member 30 is lowered relative to the hook member 20 compared to Fig. 2A, and the lid portion 33 of the pressing member 30 is blocking the entrance 22 of the hook member 20. This state is the position where the pressing member stops descending relative to the hook member when there is a linear object C in the recess 21. By blocking the entrance 22 with the lid portion 33, the linear object C in the recess will not fall out of the entrance 22 to the right in Fig. 2B when the linear object pick-up hand 10 is raised to lift up the linear object C.

[0033] On the other hand, when the linear object C in the recess is tilted from the horizontal when the linear object pick-up hand 10 is raised to lift the linear object C, the linear object C may slip in the length direction of the linear object (perpendicular to the paper surface of FIG. 2B) and fall off. To address this problem, in FIG. 2B, the front end 35 of the side portion 34 is preferably at the same position as or lower than the upper end of the inlet 22 in a side view. This provides the same effect as when the width Wh of the hook member is increased by the thickness of the side portion 34, and the linear object C in the recess 21 is prevented from tilting from the horizontal, making it difficult for the linear object C to slip in its length direction and fall off. In FIG. 2B, more preferably, the front end 35 of the side portion 34 presses the linear object C in the recess 21 toward the tip side. The strength with which the front end 35 presses the linear object C may be large enough to prevent the linear object from moving in its length direction. As a result, the linear object C in the recess 21 is held by the front end 35 and the inner surface of the tip side of the recess 21, and the linear object C does not slip in its length direction and fall off.

[0034] 3A, when there is no linear object in recess 21, pressing member 30 blocking inlet 22 passes beyond the position shown in FIG. 2B and descends further to the tip side relative to hook member 20, reaching the lower end sliding position.

[0035] 3A and 3B, an optical sensor 54 capable of detecting the hook member 20 is provided on the upper surface of the second base member 50. The optical sensor 54 is composed of a light-emitting portion 54A and a light-receiving portion 54B. When the pressing member 30 is between the positions of FIG. 2A and FIG. 2B with respect to the hook member, the light irradiated from the light-emitting portion 54A passes through the notch portion 24 of the hook member and is received by the light-receiving portion 54B. When the pressing member 30 descends to the position of FIG. 3A with respect to the hook member 20, the light irradiated from the light-emitting portion 54A is blocked by the hook member 20 and does not reach the light-receiving portion 54B, and it can be detected that the pressing member 30 has descended too far with respect to the hook member 20 from the position assumed when a linear object is present in the recess 21. In this way, by detecting the positional relationship between the hook member and the pressing member in the longitudinal direction at the lower end portion, it can be detected whether or not a linear object is present in the recess 21. The hook member 20 has a recess 21 and an inlet 22 machined to an appropriate size according to the diameter of the linear object to be picked up, and the position of the notch 24 is provided at an appropriate position in accordance with the recess and the inlet.

[0036] Next, a method for picking up a linear object using the linear object pick-up hand 10 of this embodiment will be described with reference to FIGS.

[0037] First, referring to Fig. 4, a bundle of linear objects C is placed on a supply tray 60. The supply tray 60 has a placement surface 63 and a wall 61 on one side thereof. The end of the placement surface 63 opposite the wall 61 is curved upward to prevent the linear objects C from falling off the placement surface. A groove 62 and a slit 64 are formed in the center of the wall 61 and the center of the placement surface 63, respectively, to prevent interference with the hook member 20 and the pressing member 30 of the linear object pick-up hand 10. Note that although Fig. 4 shows a reduced number of linear objects C, the number of linear objects supplied at one time is usually several tens to several hundreds.

[0038] With the entrance 22 of the recess 21 open, the linear object pick-up hand 10 is moved to the opposite side of the wall 61 with respect to the bundle of linear objects C, with the recess positioned slightly higher than the placement surface 63 (FIG. 5A).

[0039] The linear object pick-up hand 10 is moved toward the wall 61 and pressed against the bundle of linear objects C, causing one of the linear objects to fit into the recess (FIG. 5B). Because linear objects C are flexible and deformable, the bundle of linear objects is not densely stacked, but is stacked with wide gaps between the linear objects. Therefore, when the linear object pick-up hand is pressed against the wall 61, each linear object deforms and moves randomly, and one of the linear objects fits into the recess 21.

[0040] The presser member 30 is lowered relative to the hook member 20 to close the entrance 22 (FIG. 5C). At this time, the presser member may be lowered with the hook member stationary, or may be raised with the presser member stationary, or both the hook member and the presser member may be moved. Preferably, the presser member 30 is lowered with the hook member stationary, or the presser member is mainly lowered while the hook member is slightly raised to close the entrance. This is because when the entrance is closed, the linear object C fitted into the recess 21 is unlikely to fall out of the entrance 22. Even if the presser member 30 is lowered to press down linear objects near the entrance 22, the bundle of linear objects is wide and contains gaps, so the pressed down linear objects escape toward the wall and are not damaged.

[0041] When the pressing member 30 closes the entrance 22 of the recess 21, whether or not the linear object C has been gripped is detected by the above-mentioned optical sensor 54. If the linear object has not been gripped, the above operation is repeated.

[0042] When the linear object C is successfully grasped, with the pressing member 30 closing the entrance 22 of the recess 21, the entire linear object pick-up hand 10 is raised to a predetermined position to lift up the grasped linear object C (FIG. 5D).

[0043] Since the position of the raised linear object pick-up hand 10 is known in advance, another robot hand can grasp the picked-up linear object beside the linear object pick-up hand and receive it from the linear object pick-up hand.

[0044] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the technical concept thereof.

[0045] For example, the structure of the linear object pick-up hand, the shapes of the hook member and the pressing member, etc. may be modified as appropriate.

[0046] Furthermore, the sensor that detects the longitudinal positional relationship between the hook member and the pressing member is not limited to an optical sensor, and may be, for example, a sensor that detects the longitudinal positional relationship between the hook member and the pressing member by providing an electrical switch at the base end of the hook member and the pressing member and detecting the presence or absence of electrical continuity. Alternatively, no such sensor may be provided on the linear object pick-up hand, and an optical sensor or the like may be used to detect the presence or absence of a linear object beside the linear object pick-up hand when the linear object pick-up hand is raised. [Explanation of symbols]

[0047] 10 Linear object pick-up hand 20 Hook member 21 Recess 22 Entrance 23 Jaw 24 Cutout 28 Fixing hole 30 Holding member 31 Groove 32 Bottom part 33 Lid 34 Side part 35 Front end of side part 36 Fixed part 38 Fixing hole 40 First base member 41 Hook member through hole 42 Fixed plate 43 Rod through hole 48 Volts 50 Second base member 51 Actuator 52 Rod 53 Fixed part 54 Optical Sensor 54A Light sensor emitter 54B Light receiving part of optical sensor 58 Volts 59 Nut 60 Supply Tray 61 Wall 62 Groove 63 Placement surface 64 Slit C linear object D Total thickness of the fitted hook and clamp members Hd Height of the inlet 22 in the longitudinal direction of the hook member Th Thickness of the hook at the deepest part of the recess Wh Width of hook Ws Width of holding member

Claims

1. A hand for picking up one of the linear objects from a bundle of the linear objects, A hook member and a pressing member are included. The tip of the hook member is It is rod-shaped, an entrance through which the linear object can enter is formed on a side near the tip, and a recess is provided that is large enough to fit one of the linear objects; The tip of the pressing member is A rod-like member having a U-shaped cross section with a groove formed in the longitudinal direction, A side surface portion that constitutes a side wall of the groove; a bottom surface portion that forms the bottom of the groove and has a lid portion at a tip portion that extends longer than the side surface portion; The hook member and the pressing member are The hook member is fitted to the pressing member so that the inlet faces the bottom surface portion and fits into the groove, The lid portion is relatively slidable in the longitudinal direction at least between a position where the lid portion closes the inlet and a position where the lid portion is located closer to the base end side of the hook member than the inlet and opens the inlet. Linear object pick-up hand.

2. The hook member and the pressing member are relatively slidable in the longitudinal direction at least between a position where the lid portion closes the entrance and the front end of the side portion can press the linear object fitted in the recess toward the tip end of the hook member, and a position where the lid portion is located on the base end side of the hook member relative to the entrance and opens the entrance. The linear object pick-up hand according to claim 1.

3. A jaw portion formed between the tip of the hook member and the recess is wedge-shaped so that the recess becomes wider toward the inlet. The linear object pick-up hand according to claim 1.

4. Further comprising a sensor for detecting a positional relationship between the hook member and the pressing member in a longitudinal direction. The linear object pick-up hand according to claim 1.

5. A method for picking up a linear object using the linear object pick-up hand according to any one of claims 1 to 4, comprising the steps of: placing the bundle of linear objects on a placement surface having a wall on one side thereof so as to be substantially parallel to the wall; a step of pressing the linear object pick-up hand against the bundle of linear objects from a direction opposite to the wall while the entrance is open, thereby fitting one of the linear objects into the recess; a step of moving the hook member and / or the pressing member in a longitudinal direction to close the inlet with the lid portion; lifting the entire linear object pick-up hand; A method for picking up a linear object comprising the steps of:

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