JP2011051081A - Holding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a holding device capable of surely retaining deformation of a workpiece such as a corrugated board box to the minimum, which is apt to easily deform and is weak in strength, and surely holding the workpiece in response to workpiece sizes. <P>SOLUTION: The holding device 1 is provided with a horizontal angle frame 2 mounted on an arm tip 22 of a robot, a fixed holding section 3 which hangs down from a short-side and has a holding plane 4, a moving section 5 at the other side, a movable holding section 6 which hangs down from the moving section and has a holding plane 7, a detection moving section 9 arranged on the moving section, a spring 12 for urging the detection moving section, a detection plate 10 which hangs down from the detection moving section and has a contact plane 11, and a detector 13 for outputting a signal when a difference between the contact plane of the detection plate and the holding plane of the holding section becomes below a designated amount. Further, claws 3e, 6e extending in a direction of a mating side each other are respectively arranged on the lower parts of the movable and fixed holding sections. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a gripping device that attaches a box such as a cardboard box to the tip of an arm of a robot for separating, transporting, stacking, and the like by a robot.

  2. Description of the Related Art Conventionally, a gripping device attached to the tip of a robot that transports an article grips or releases an article by expanding or contracting a gap between a pair of gripping portions such as a plate shape or a rod shape that hangs oppositely. When the article is a cardboard box or the like, for example, in Patent Document 1, a fixed flat plate is provided by hanging a fixed flat plate on one side of a rectangular horizontal square frame and moving the movable plate forward and backward to the other side. Adjusting the opening degree of the movable plate and the movable flat plate, the both side surfaces of the cardboard box facing each other are held and conveyed. Furthermore, a claw is provided at the lower end of each flat plate so as to be able to move forward and backward or rotate so that the bottom of the cardboard box can be held. However, since the strength of the cardboard box is weak, it may be deformed if it is gripped with a very strong pressing force. Therefore, in Patent Document 2, a substantially L-shaped hand is used instead of a flat plate, and it is held at the opposite corners of the corrugated cardboard box to reduce the influence of the pressing force on the corrugated cardboard box, thereby ensuring a reliable grip. I try to do it.

  However, cardboard boxes have various dimensions and are not strong. Therefore, it is necessary to control the opening degree and the pressing force of the gripping portion in accordance with it. Therefore, for example, dimension data is recorded in the control device in advance, and the opening size of the gripping part before gripping and the dimension after gripping are stored in the control side in advance. It is also conceivable to measure or detect the pressing force or width dimension of the cardboard box. Therefore, in Patent Document 3, although it is a case of a cathode ray tube of a television, an elastic body of a rubber pad is attached to the grip portion, and further, a limit switch and a metal sensor are attached. Then, by grasping the cathode ray tube, it is detected that the rubber pad is deformed and the limit switch or the metal sensor works, and this is used as a grasping completion signal. Further, in Patent Document 4, a spring and a limit switch are provided in a fixed gripping part, and various workpieces flowing on the belt conveyor are pressed by the operating gripping part and held by the fixed gripping part. . The spring on the fixed side is gradually deformed by the pressing force of the operating side gripping part, and when a predetermined pressure is reached, a limit switch operates to hold the workpiece at a predetermined pressing force and position. Moreover, in patent document 5, a limit switch is made to operate | move by tilting of the nail | claw at the front-end | tip of a holding part. As a result, the position of the work is detected by detecting the position where the nail is moved horizontally and the work hits the work so that the nail comes to a height slightly lower than the work height.

JP 2007-15026 A JP 7-290393 A JP-A-11-221788 Japanese Utility Model Publication No. 3-62787 No. 7-48585

  However, Patent Documents 1 and 2 do not mention detection of cardboard boxes, measurement of dimensions, and the like. Further, in the cardboard box that is easily deformed and weak in strength, the one in Patent Document 3 is weaker on the cardboard box side than an elastic body such as urethane or rubber, so that the cardboard box side is deformed and is difficult to detect. Moreover, a metal detection apparatus etc. cannot be used. Moreover, although the thing of patent document 4 can be hold | gripped according to various workpiece | work widths, since it hold | maintains with the pressing force by a spring, grip force is insufficient. In addition, the gripping force varies due to vibration or the like. Furthermore, it is difficult to reliably grip a large object such as a cardboard box. Moreover, the thing of patent document 5 does not measure the width | variety or length dimension of a workpiece | work.

  In view of such problems described above, the object of the present invention is to minimize deformation of a box-shaped workpiece that is easily deformed and weak in strength, such as a cardboard box, and holds the workpiece securely. It is an object of the present invention to provide a gripping device that can securely grip a workpiece in accordance with the above.

  In the present invention, a fixed grip having a mounting portion attached to the tip of an arm of a robot, a rectangular horizontal rectangular frame supported by the mounting portion, and a gripping plane hanging from one short side of the horizontal rectangular frame A moving part provided on the other side of the horizontal rectangular frame and capable of moving forward and backward in the direction of the fixed holding part, a moving holding part having a holding plane hanging from the moving part, and the moving holding part. A central vertical hole, a detection moving part provided in the moving part and supported so as to be able to advance and retreat in the direction of the fixed gripping part, and a spring provided in the moving part for biasing the detection moving part in the direction of the fixed gripping part A detection plate having a contact plane that is at least half the length of the gripping plane that hangs down from the detection moving unit so as to be able to enter and leave the central vertical hole, a contact plane of the detection plate, and a gripping plane of the moving gripping unit The difference between And a detector that outputs a signal when the gripping plane of the movable gripping portion and the contact plane of the detection plate are arranged to face the gripping plane of the fixed gripping portion, and the movable gripping portion And the subject mentioned above was solved by providing the nail | claw which was mutually provided in the other party direction in the lower part of the said fixed holding | grip part.

  That is, the workpiece is held between the opposed gripping plane and the fixed gripping portion having the claws and the movable gripping portion, so that the workpiece can be securely held as in the conventional case. In the present invention, in particular, when gripping a workpiece, the workpiece gripping width, that is, the distance between the fixed gripping portion and the moving gripping portion is determined by the contact plane of the detection plate entering and exiting the central vertical hole portion of the moving gripping portion and the gripping of the moving gripping portion. Since it can be set by a detector that outputs a signal when the difference from the flat surface is less than a predetermined amount, it can be set to a predetermined gripping length simply by gripping without setting various workpiece data in advance. . Furthermore, since the box can be set by the width of the box or a few mm smaller than the box instead of pushing the box, the box is not pushed by an excessive force. Further, since the position is held, there is no change in the pressing force, and there is no variation in gripping force due to vibration. The detection plate is urged by a spring in the direction of the anti-moving gripping part and moves with the movement of the moving gripping part. A sufficiently long contact plane first comes into contact with the box, and the detection plate moves by being pushed by the box. Since it is pushed toward the gripping part, it is easy to detect the gripping length even in a partially deformed cardboard box. It should be noted that by increasing the spring force, even a deformed cardboard box surface can be corrected and gripped to some extent.

  As described above, in the present invention, the workpiece can be securely held as in the prior art, and the gripping length of the workpiece by the fixed gripping portion and the movable gripping portion can be automatically set according to various workpiece lengths. By gripping, it grips with an appropriate width, does not push the box with an excessive force, easily deforms a corrugated cardboard box or the like, and securely grips without weakly deforming a work. In addition, since there is no change in the pressing force and there is little variation, the false fall is reduced. Furthermore, the workpiece can be reliably gripped in accordance with the size of the workpiece to be gripped without giving data in advance. In addition, since the detection plate is provided with a detection plane that is more than half of the holding plane, the gripping length can be easily detected even in a deformed cardboard box, so that erroneous gripping and erroneous dropping of the work can be reduced. Furthermore, the adjustment of the gripping length is simple because only the position of the detector and the detection plate with respect to the movable gripping part needs to be adjusted. Since the detection plate can have a large stroke, it can be applied to various kinds of workpieces. Furthermore, the nail can be enlarged and the fall prevention can be improved.

It is a front view of a grasping device showing an embodiment of the invention. It is the sectional view on the AA line of FIG. It is the BB sectional view taken on the line of FIG. It is front explanatory drawing which shows the use condition of the holding | grip apparatus which shows embodiment of this invention, (a) is the state before holding a cardboard box, (b) made the fixed holding part contact the front-end | tip of a cardboard box. The state, (c) shows a state where the movable gripping part is moved, (d) shows a state where gripping is detected, and (e) shows a state where gripping is completed and moved upward.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view of a gripping apparatus showing an embodiment of the present invention, FIG. 2 is a view taken along the line AA in FIG. 1, and FIG. 3 is a view taken along the line BB. As shown in FIG. 1, the gripping device 1 of the present invention is attached to a tip 22 of a robot arm 21 showing a part via an attachment portion 27 provided at the upper center side of a rectangular horizontal rectangular frame 2. It has been. The mounting portion 27 is tilted and attached to the robot arm tip mounting surface 22 so that the operating range of the robot can be widened while maintaining the horizontal state of the horizontal rectangular frame 2. The fixed grip 3 is suspended from one short side 2a of the horizontal square frame 2. The fixed grip portion 3 is composed of two aluminum square members 3a and 3b suspended from a horizontal rectangular frame at a distance and horizontal plates 3c and 3d for fixing both the square members in the lateral direction at substantially the central portion and the lower portion. . A claw 3e is provided at the lowermost end of the fixed grip portion 3 so that the tip in the horizontal direction faces inward (left side as viewed in FIG. 1). The inner surfaces in the vertical direction (leftward as viewed in FIG. 1) of the square members 3a, 3b and the horizontal plates 3c, 3d are all flat, and are generally made to be substantially the same plane as a whole. A plane 4 is formed.

  A moving portion 5 is provided on the other side 2b of the horizontal rectangular frame 2. The moving part 5 can be moved in the longitudinal direction of the horizontal rectangular frame 2 by a linear guide 23, and can be driven by a servo motor 25 and a ball screw 26 so as to advance and retreat in the direction of the fixed gripping part (movable in the left-right direction as viewed in FIG. 1). Has been. The moving grip 6 is suspended from one end (left side in the figure) of the moving unit 5. The movable gripping portion 6 is composed of two aluminum-made moving-side square members 6a and 6b that hang from the moving portion at a distance, and a horizontal plate 6d that fixes the lowermost ends of both square members in the lateral direction. A claw 6e is provided at the lower end of the moving side so that the horizontal front end faces inward (right side as viewed in FIG. 1). The inner side surfaces (rightward as viewed in FIG. 1) of the moving side square members 6a and 6b and the horizontal plate 6d are all flat, and are formed to be substantially the same plane as a whole to form the holding plane 7 of the moving holding portion. To do. A central vertical hole 8 is formed between the moving-side square members 6a and 6b. The heights of the claws 3e and 6e of the fixed grip portion 3 and the movable grip portion 6 are the same and extend in the opposite direction. Anti-slip materials 4a and 7a such as rubber, file, or synthetic resin are attached to the square material gripping surfaces 4 and 7.

  A detection moving unit 9 is provided at substantially the center of the moving unit 5. The detection moving unit 9 can be moved in the longitudinal direction of the moving unit 5 by the linear guide 24, and can be moved back and forth in the direction of the fixed gripping unit (moved in the left and right direction as viewed in FIG. 1). Stoppers (not shown) are provided at both ends of the linear guide of the detection moving unit 9 to prevent the detection moving unit from falling off the moving unit 5 and restrict the movement of the detection moving unit toward the fixed gripping unit. A detection plate 10 hangs down from the detection moving unit 9. The detection plate 10 has a hollow quadrangular cross section, and the inner side surface (rightward as viewed in FIG. 1) of the detection plate is a contact plane 11. The detection plate 10 can enter and exit the central vertical hole 8 and has a length that is more than half of the fixed or moving side holding planes 4 and 7. The holding plane 7 of the movable holding unit 6 and the contact plane 11 of the detection plate 10 are arranged to face the holding plane 4 of the fixed holding unit.

  A spring mounting portion 10 a is provided on the upper fixed grip portion side of the detection plate 10. The moving part 5 is provided with a spring fixing part 5a extending from the moving part toward the fixed gripping part so as to have a substantially S-shape. A spring 12 is locked between the spring mounting portion 10a and the spring fixing portion 9a. The spring 12 urges the detection moving unit 9 and the detection plate 10 attached to the detection moving unit toward the fixed gripping unit.

  A limit switch 13 is provided as a detector on the side of the upper gripping portion of the movable gripping portion 6. The dock 13a of the limit switch can be brought into contact with the side surface 10b opposite to the detection plate 10 so that a signal can be output by contacting the detection plate. The contact position can be adjusted so that a signal can be output when the difference between the contact plane 11 of the detection plate and the grip plane 7 of the movable gripping portion becomes a predetermined amount or less. Here, it is set so that a signal can be output at a position where the contact plane 11 of the detection plate and the grip plane 7 of the movable gripper coincide.

  A method of using this gripping apparatus will be described. FIG. 4 is a front explanatory view showing a use state of the gripping apparatus 1 showing the embodiment of the present invention, and is an explanatory view about a case where the cardboard box 31 is gripped. Note that part or all of the description of the same parts as described above is omitted. In FIG. 4A, the cardboard box 31 is transported from a slot (not shown) to the roller conveyor 32, and stops when the cardboard box tip 31a is in contact with the stopper 33. At this position, the rollers 34 of the roller conveyor 32 have a small diameter 34a at the center in the width direction, and a bottom surface 31d and a gap 35 are provided at the center in the longitudinal direction of the cardboard box. The width and height of the gap 35 are larger than the widths and heights of the claws 3e and 6e, and the claws can be inserted into the bottom 31d of the cardboard box. The stopper 33 is notched so as not to interfere with the claw 3e.

  Since the position of the cardboard box tip 31a and the gap 35 are constant, they can be stored in advance in the robot controller. Accordingly, the robot (not shown) is configured so that the position of the fixed gripping portion of the gripping device with the claw 3e, 6e is lowered until it comes below the height of the bottom 31d. .

  Next, as shown in FIG. 4 (b), the fixed gripping portion 3 is moved to the cardboard box tip 31a side slightly beyond the cardboard box tip position, and the tip of the cardboard box and the gripping surface 4 of the fixed gripping portion are moved. Make contact. Next, the moving unit 5 (the detection moving unit 9, the moving holding unit 6, the detection plate 10 and the like) of the holding device 1 is moved to the fixed holding unit 4 side. With the movement, as shown in FIG. 4C, first, the contact surface 11 of the detection plate 10 comes into contact with the rear end 31b of the cardboard box. Further, the moving unit 5 (moving gripping unit 6) moves toward the cardboard box, but the detection plate 10 is held at the contact position of the rear end 31b of the cardboard. At this time, the detection plate 10 presses the rear end 31 b of the cardboard with the urging force of the spring 12.

  Furthermore, the moving part 5 (moving gripping part 6) moves, and the gripping surface 7 of the moving gripping part 6 contacts the rear end 31b of the cardboard box as shown in FIG. 4 (d). At the same time, the contact surface 11 of the detection plate and the gripping surface 7 of the moving gripping part coincide with each other, so that the limit switch 13 is actuated to output a signal and the moving part 5 stops. As a result, the length between the gripping surfaces 4 and 7 of the movable gripping part 6 and the fixed gripping part 3 is made the same as or slightly shorter than the length of the cardboard box 31 (slightly stopping the motor stop or signal For example, the cardboard box can be pinched.

  As a result, the cardboard box 31 is securely gripped, and as shown in FIG. 4E, the robot can be operated to carry the cardboard box in the next stroke. There is a slight gap between the bottom 31d of the cardboard box and the claws 3e, 6e. Since it can prevent, the cardboard box 31 can be conveyed reliably.

  Of course, the heights of the movable gripping portion 6, the fixed gripping portion 3, and the detection plate 10 are set so as not to interfere with the cardboard box 31 to be gripped. In addition, although an example is given here, it is needless to say that this method is an example, and various applications and uses are possible. For example, if the spring 12 is strengthened to some extent, the tip of the cardboard box can be brought into contact with the gripping surface of the fixed gripping part without pressing the tip of the cardboard box on the fixed side. Further, although the position of the cardboard box is mechanically fixed, the position of the cardboard box may be detected using a visual device or the like. It is also possible to measure the amount of movement of the movable gripping part and compare it with pre-input data, and use it for judgment of cardboard box type, confirmation of shape, recording of deformation, adjustment of gripping force (position), etc. It is. Moreover, various forms, such as a conveyor and a stopper, are possible.

DESCRIPTION OF SYMBOLS 1 Gripping device 2 Horizontal square frame 2a One short side 2b The other short side 3 Fixed grip part 3e Claw 4 Grip plane 5 of a fixed grip part Moving part 6 Moving grip part 6e Claw 7 Grip plane 8 of a movable grip part Central vertical hole part 9 Detection moving part 10 Detection plate 11 Detection plate contact plane 12 Spring 13 Detector (limit switch)
22 Arm tip 27 Mounting part

Claims (1)

  A mounting portion attached to the end of a robot arm; a rectangular horizontal square frame supported by the mounting portion; a fixed gripping portion having a gripping plane hanging from one short side of the horizontal corner frame; and the horizontal A moving part provided on the other side of the square frame and capable of moving back and forth in the direction of the fixed holding part; a moving holding part having a holding plane hanging from the moving part; and a central vertical hole provided in the moving holding part; A detection moving part provided in the moving part and supported so as to be able to advance and retreat in the direction of the fixed gripping part; a spring provided in the moving part for biasing the detection moving part in the direction of the fixed gripping part; and the central vertical hole A difference between a detection plane having a contact plane that is more than half the length of the gripping plane that hangs down from the detection moving section so as to be able to enter and exit the section, and a contact plane of the detection plate and the gripping plane of the movable gripping section is a predetermined amount Signal when An output detector, and a grip plane of the movable gripper and a contact plane of the detection plate are arranged to face a grip plane of the fixed gripper, and the movable gripper and the fixed gripper A gripping device characterized in that claws extending in the opposite direction are provided at the lower part.

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