Pressing plate and edge folding device

Abstract

The present invention provides a pressing plate and an edge folding device that can suppress an occurrence of tearing and wrinkling of packaging paper.　The pressing plate is attached to an arm distal end of an articulated robot provided to an edge folding device that performs edge folding of an end surface covering portion of a packaging material for packaging a metal strip coil, said portion covering an axial end surface of the metal strip coil. The pressing plate is used to press the end surface covering portion against the axial end surface of the metal strip coil. An outer edge of a portion of the pressing plate corresponding to a leading side in a travel direction which is a direction toward which the pressing plate is moved when a fold of a valley fold is formed in the packaging material is chamfered on a side of a pressing surface that contacts the packaging material, hence is suitable for smoothly forming the fold up to a vicinity of the outermost peripheral portion of the metal strip coil without damaging the packaging material when the valley fold is formed. In plan view, the pressing plate has an asymmetrical protruding shape in a left-right direction with respect to the travel direction in plan view so that no portion other than the distal end portion in the travel direction reaches the outermost peripheral portion of the metal strip coil and all apex portions including the distal end portion are rounded.

Description

Presser plate and edge folding device

[0001] The present invention relates to a presser plate attached to the end of an arm of a multi-joint robot provided in an edge folding device, and to an edge folding device provided with the multi-joint robot.

[0002] Metal strips rolled by a rolling mill are wound by a winding machine and transported in the form of coils. These metal strip coils are usually packaged in packaging material to prevent scratches, etc. Packaging material that is wider than the width of the metal strip coil is used. The packaging material covers the side (curved surface) of the cylindrical metal strip coil and is placed over the metal strip coil so that the end surface covering portions, which cover the axial end surfaces of the metal strip coil, extend beyond the metal strip coil in the coil axial direction. Numerous pleats (folded portions) are formed in the end surface covering portions by a selvedge folding operation, and the end surface covering portions tightly fit the metal strip coil and cover its axial end surfaces.

[0003] Patent Document 1 discloses a device for folding the edge of a packing paper in packaging a metal strip coil.

[0004] Japanese Patent Application Publication No. 9-156610

[0005] The edge folding process for packaging coils (metal strip coils) is one of the most delicate processes in coil packaging, as it must be free of tears that impair the functionality of the packaging itself, wrinkles that impair the appearance quality, and other defects that hinder the edge folding process. However, the device in Patent Document 1 does not take into consideration tears and wrinkles that may occur in the packaging material during the edge folding process.

[0006] The present invention was made in consideration of the above circumstances, and aims to provide a pressure plate and edge folding device that can form good folds along the entire radial direction of a metal strip coil while suppressing tearing and wrinkling of the packaging material.

[0007] The present application includes multiple means for solving the above-mentioned problems, and one example thereof is a pressure plate attached to the tip of the arm of a multi-joint robot equipped in an edge folding device that folds the edge of an end surface covering portion, which is part of the packaging material that packs a metal strip coil and covers the axial end surface of the metal strip coil, and is used to press the end surface covering portion against the axial end surface of the metal strip coil.The outer edge of the portion that is at the front in the traveling direction, which is the direction in which the pressure plate is moved when forming a valley fold in the packaging material, is chamfered on the side of the pressing surface that comes into contact with the packaging material, and is suitable for smoothly forming the fold up to the vicinity of the outermost periphery of the metal strip coil without damaging the packaging material when forming the valley fold.The pressure plate has a convex shape that is asymmetrical with respect to the traveling direction in a plan view, so that no portion other than the tip in the traveling direction reaches the outermost periphery of the metal strip coil, and the tip is rounded.

[0008] According to the present invention, a pressure plate and edge folding device are provided that can form good folds along the entire radial direction of a metal strip coil while suppressing tearing and wrinkling of the packaging material.

[0009] 1 is a diagram illustrating an embodiment of an edge folding device. FIG. 1 is a diagram illustrating an example of the configuration of a first end effector. FIG. 2 is a diagram illustrating an example of the configuration of a second end effector. FIG. 2 is a diagram illustrating an embodiment of a presser plate of the present invention. FIG. 3 is a diagram illustrating an embodiment of a presser plate of the present invention. FIG. 4 is a diagram illustrating an embodiment of a presser plate of the present invention. FIG. 5 is a diagram illustrating a state up to coil packaging of a metal strip coil. FIG. 6 is a diagram illustrating a state up to coil packaging of a metal strip coil. FIG. 7 is a diagram illustrating a state up to coil packaging of a metal strip coil. FIG. 8 is a diagram illustrating a first operation of the first articulated robot and a second articulated robot. FIG. 9 is a diagram illustrating a second operation of the first articulated robot and a second articulated robot. FIG. 10 is a diagram illustrating a third operation of the first articulated robot and a second articulated robot. FIG. 11 is a diagram illustrating a fourth operation of the first articulated robot and a second articulated robot. FIG. 12 is a diagram illustrating an example of a case where the pleat shape is poor, as a comparative example. FIG. 13 is a diagram illustrating an example of a procedure for stabilizing the pleat shape. FIG. 14 is a diagram illustrating an example of a procedure for stabilizing the pleat shape. FIG. 15 is a diagram illustrating an example of a procedure for stabilizing the pleat shape. FIG. 16 is a diagram illustrating an example of a pleat shape obtained by the presser plate of the present embodiment. FIG. 17 is a diagram illustrating a fifth operation of the first articulated robot and the second articulated robot. FIG. 18 is a diagram illustrating an example of a case where tearing of the packing paper occurs, as a comparative example. 10 is a diagram showing an example of a comparative example in which tearing of packing paper occurs; FIG. 11 is a diagram showing an example of formation of a valley fold line by the presser plate of the present embodiment; FIG. 12 is a diagram showing an example of a comparative example in which a collision occurs with wrinkles in packing paper; FIG. 13 is a diagram showing an example of a state when the presser plate of the present embodiment is moving; FIG. 14 is a diagram showing an example of a miswinding of the outermost portion of a coil; FIG. 15 is a diagram showing an example of a comparative example in which a rectangular presser plate collides with the outermost portion of a coil; FIG. 16 is a diagram showing an example of prevention of a collision with a miswinding of the outermost portion of a coil by the presser plate of the present embodiment; FIG. 17 is a diagram showing a sixth operation of the first articulated robot and the second articulated robot; FIG. 18 is a diagram showing an example of a flow of wrinkles by the presser plate of the present embodiment; FIG. 19 is a diagram showing an example of a flow of wrinkles by the presser plate of the present embodiment;

[0010] An embodiment of the present invention will now be described with reference to the accompanying drawings. FIG. 1 illustrates an embodiment of an edge folding device 100 according to the present invention. The edge folding device 100 is a device that automatically folds the edge of an end covering portion, which is part of a packaging material used to package a cylindrical metal strip coil (see FIG. 5 below), and covers the axial end of the metal strip coil (also referred to as a "coil"). While a paper sheet (packaging paper) is preferably used as the packaging material in this embodiment, other sheet materials commonly used for packaging metal strip coils, such as a resin sheet, can also be used. Details of the edge folding operation will be described later. As shown in FIG. 1, the edge folding device 100 includes a relative position detection unit 10, a control unit 20, and a robot unit 90. The relative position detection unit 10, the control unit 20, and the robot unit 90 can transmit and receive information to and from each other via wired or wireless communication.

[0011] The relative position detection unit 10 can detect relative position information regarding the relative position between the robot unit 90 and the metal strip coil. The robot unit 90 can perform edge folding of the end surface covering portion of the packing paper that covers the side (curved surface) of the metal strip coil. The control unit 20 can control the robot unit 90 based on the relative position information detected by the relative position detection unit 10. With this configuration, the relative position detection unit 10 can detect relative position information regarding the relative position between the robot unit 90 and the metal strip coil and control the robot unit 90 based on the detected relative position information, even if the metal strip coil to be edge folded (packaged) is not placed in a predetermined position. This eliminates the need to place the metal strip coil in a fixed position, and the placement can be changed, thereby increasing the flexibility of the equipment layout. Each unit will be described in detail below.

[0012] The relative position detection unit 10 includes a LiDAR (Light Detection and Ranging) sensor 11 that functions as a three-dimensional measurement device, a calculation unit 12, and an output unit 13. The LiDAR sensor 11 emits laser light and detects reflected light and scattered light, which can be used to measure the distance to the metal strip coil and calculate the shape. The LiDAR sensor 11 can also generate high-resolution 3D images of the metal strip coil by including a camera. The LiDAR sensor 11 can detect three-dimensional position information of the metal strip coil.

[0013] The calculation unit 12 can calculate relative position information regarding the relative positions of the robot unit 90 and the metal band coil based on the position information of the robot unit 90 and the three-dimensional information of the metal band coil detected by the LiDAR sensor 11. The position information of the robot unit 90 may be stored in the memory unit 24 of the control unit 20, for example, and acquired from the memory unit 24.

[0014] The output unit 13 outputs the relative position information calculated (detected) by the calculation unit 12 to the control unit 20. This allows the control unit 20 to acquire relative position information between the robot unit 90 and the metal strip coil according to the position of the metal strip coil, regardless of the arrangement position of the metal strip coil.

[0015] The robot unit 90 includes a first articulated robot 70, a second articulated robot 80, and a moving unit 60. The first articulated robot 70 and the second articulated robot 80 are attached to the moving unit 60, and the moving unit 60 enables the first articulated robot 70 and the second articulated robot 80 to move in translation and rotate. In this embodiment, collaborative robots that can work with humans are used as the first articulated robot 70 and the second articulated robot 80. Based on the relative position information, the control unit 20 can control the moving unit 60 to move the edge folding robot to a position where the metal strip coil and the edge folding robot are positioned in a predetermined manner. This eliminates the need to position the metal strip coil in a fixed location and allows the position to be changed, thereby increasing the flexibility of facility layout.

[0016] The moving unit 60 includes a rotating table 30, an elevator 40, and a mobile carriage 50. The rotating table 30 is fixed to the elevator 40 and includes a drive unit 31 and a robot table 32. The elevator 40 is installed on the mobile carriage 50 and includes a drive unit 41. The mobile carriage 50 includes a drive unit 51. The first articulated robot 70 and the second articulated robot 80 are attached to the robot table 32 (rotating table 30). The drive unit 31 is configured, for example, by a servo motor. Upon receiving a control signal from the control unit 20, the drive unit 31 can rotate the robot table 32 (rotating table 30) around a rotation axis based on the received control signal. The central axis of rotation of the robot table 32 is oriented horizontally. Note that the central axis of rotation of the robot table 32 is not limited to being horizontal, and may be oriented in a direction tilted by a predetermined angle from the horizontal depending on the installation state of the metal strip coil. By setting the central axis of rotation of the robot table 32 in a predetermined direction, a reference direction can be set for the manipulation of packaging paper by the first articulated robot 70 and the second articulated robot 80. The relative position detection unit 10 may be provided at a predetermined position on the turntable 30 (for example, a portion other than the robot table 32). The positional relationship between the attachment position of the relative position detection unit 10, a predetermined position on the central axis of rotation of the robot table 32, and the direction of the central axis can be determined in advance.

[0017] The drive unit 51 is configured, for example, by a combination of a servo motor and a transmission mechanism, and upon receiving a control signal from the control unit 20, can move the movable carriage 50 two-dimensionally horizontally on the floor surface based on the received control signal. The drive unit 41 is configured, for example, by a combination of a servo motor and a transmission mechanism, and upon receiving a control signal from the control unit 20, can raise and lower the rotating table 30 based on the received control signal. In this way, the control unit 20 can move the lifting unit 40 horizontally by sending a control signal to the drive unit 51 to move the movable carriage 50 horizontally. The control unit 20 can also raise and lower the rotating table 30 by sending a control signal to the drive unit 41 to move the lifting unit 40 vertically. The control unit 20 can also rotate the robot table 32 by sending a control signal to the drive unit 31.

[0018] The first articulated robot 70 may be, for example, a six-axis robot. A six-axis robot has six degrees of freedom in three-dimensional space (XYZ coordinate system), including the X-axis, Y-axis, Z-axis, and around the X-axis, Y-axis, and Z-axis. The first articulated robot 70 includes multiple joints with rotation axes, multiple links connecting the joints, and a first end effector 71 at its tip. The second articulated robot 80 is also a six-axis robot, and includes a second end effector 81 at its tip. Operation programs are created for the first articulated robot 70 and the second articulated robot 80 so that they can perform predetermined tasks in a predetermined procedure. The operation programs may be stored, for example, in the memory unit 24.

[0019] When the first articulated robot 70 and the second articulated robot 80 receive a control signal from the control unit 20, they can perform a predetermined task in a predetermined procedure based on the received control signal. In this case, the control signal may be a signal to start or stop operation of the first articulated robot 70 and the second articulated robot 80, and a device for storing specific procedures and operations may be built into the first articulated robot 70 and the second articulated robot 80.

[0020] By using a multi-joint robot, the position and posture of the first end effector 71 and the second end effector 81 can be controlled, making it possible to work in three-dimensional space, thereby reproducing the packaging work (edge ​​folding work) performed manually by humans.

[0021] The control unit 20 includes a CPU (Central Processing Unit) 21, a RAM (Random Access Memory) 22, a ROM (Read Only Memory) 23, a storage unit 24, and an interface unit 25. The control unit 20 can be configured, for example, as an information processing device such as a personal computer. The storage unit 24 can be configured as a semiconductor memory or a hard disk, and can store the operation program of the edge folding device 100, processing results, and other required information. The interface unit 25 includes a communication module and can send and receive information between the relative position detection unit 10 and the robot unit 90.

[0022] FIG. 2 shows an example of the configuration of the first end effector 71. The first end effector 71 includes a pressure plate 72, a roll portion 714 on which adhesive tape is wound in a roll, and an application portion 713 that cuts the adhesive tape wound on the roll portion 714 to a required size and applies the cut adhesive tape. The pressure plate 72 presses the end surface covering portion of the packing paper against the axial end surface of the metal strip coil. Details of the pressure plate 72 will be described later. The application portion 713 fixes the edge-folded portion of the packing paper by applying the adhesive tape cut to a required size to the packing paper. The first end effector 71 can rotate in the direction indicated by symbol A in FIG. 2 and move in the direction indicated by symbol B. The application portion 713 can move in the direction indicated by symbol B while maintaining the position of the pressure plate 72.

[0023] FIG. 3 is a diagram showing an example of the configuration of the second end effector 81. The second end effector 81 includes grippers 811 and 812. The grippers 811 and 812 are collectively referred to as the gripper 81. The grippers 811 and 812 can be configured as flat plates of a desired shape. The grippers 811 and 812 can rotate around a predetermined axis. The gripper 81 can grip the end of the end surface covering portion of the packing paper. Specifically, the grippers 811 and 812 can pinch and grip the end of the end surface covering portion of the packing paper from both sides. The second end effector 81 can rotate in the direction indicated by symbol A in FIG. 3 and move in the direction indicated by symbol B. The gripper 81 has a grip detection function that utilizes force control.

[0024] This makes it possible to grip the end of the end surface covering portion of the packing paper, move or rotate the end in a required direction, and maintain the position of the end in a gripped state.

[0025] Figures 4A, 4B, and 4C are diagrams showing one embodiment of the presser plate 72 of the present invention. Figure 4A shows the front shape of the presser plate 72, Figure 4B shows the side shape as seen from the reference character BB in Figure 4A, and Figure 4C shows the cross-sectional shape as seen from the reference character CC in Figure 4A. The presser plate 72 is attached to the tip of the arm of an articulated robot 70 included in an edge folding device 100 that folds the edge of an end surface covering portion 301, which is part of the packing paper 300 that packs the metal strip coil 200 and covers the axial end surface 201 of the metal strip coil 200, and is used to press the end surface covering portion 301 against the axial end surface 201 of the metal strip coil 200.

[0026] The outer edge of the presser plate 72 is chamfered on the side of a pressing surface 728 that contacts the packing paper 300. In this embodiment, as described below, the presser plate 72 has a tapered surface 730 formed in a tapered shape. Furthermore, the outer edge of the portion of the presser plate 72 that is on the leading side in the traveling direction, which is the direction in which the presser plate 72 is moved when forming valley folds in the packing paper 300, has a convex shape that is asymmetrical with respect to the traveling direction in plan view so that no portion other than the tip 723 in the traveling direction reaches the outermost periphery of the metal strip coil, and all apexes including the tip 723 (in this embodiment, the tip 723, the connection portion between the first inclined edge 722 and the first edge 721, and the connection portion between the second inclined edge 724 and the second edge 725) are rounded.

[0027] Therefore, when forming the valley fold, one of the left and right sides of the outer edge of the leading portion (the portion closest to the valley fold line) protrudes to reach the vicinity of the outermost periphery of the metal strip coil, allowing the fold to be formed up to that position. Furthermore, to prevent the presser plate 72 from colliding with the winding slippage of the outermost periphery (described below) when this protruding portion reaches the outermost periphery, the other of the left and right sides of the outer edge of the leading portion of the presser plate 72 is recessed further back in the direction of travel than the other of the left and right sides so as not to reach the outermost periphery of the metal strip coil at this point, resulting in an asymmetrical shape. In addition, all apexes, including the leading end 723, are rounded. Therefore, the one of the left and right sides smoothly forms the fold up to the outermost periphery of the metal strip coil without damaging the packing paper 300, and the recessed portion of the other of the left and right sides prevents the presser plate 72 from colliding with the winding slippage of the outermost periphery of the coil 200, thereby achieving good packaging quality.

[0028] In this embodiment, the presser plate 72 has a first inclined edge 722 and a second inclined edge 724 with a tip 723 between them. As described below, the first inclined edge 722 extends from a first edge 721 that is disposed along the valley fold line when the presser plate 72 is moved along the valley fold line of the packing paper 300 to form a fold, and is inclined away from the valley fold line (i.e., an extension of the first edge 721). The second inclined edge 724 connects the tip 723 to a second edge 725 that faces the first edge 721. The tip 723 is rounded.

[0029] The presser plate 72 has a third edge 726 on the side opposite to the leading end in the traveling direction, which is connected to the first edge 721 and the second edge 725. The third edge 726 has a convex shape that is symmetrical in the direction opposite to the traveling direction, and is rounded at the center and both ends.

[0030] The radius of curvature R1 of the tip portion 723 is within a range of 2 to 15 mm. More preferably, the radius of curvature R1 of the tip portion 723 may be within a range of 3 to 10 mm. The angle θ formed between the first edge portion 721 and the first inclined edge portion 722 may be within a range of 3 to 20°. More preferably, the angle θ formed between the first edge portion 721 and the first inclined edge portion 722 may be within a range of 5 to 15°. The dimension L between the extension line of the first edge portion 721 and the tip portion 723 may be within a range of 5 to 20 mm. More preferably, the dimension L between the extension line of the first edge portion 721 and the tip portion 723 may be within a range of 10 to 15 mm.

[0031] The radius of curvature R2 of the central portion of the third edge 726 is within a range of 5 to 30 mm. More preferably, the radius of curvature R2 of the central portion of the third edge 726 may be within a range of 10 to 20 mm. The inclination angle α of the third edge 726 may be within a range of 110 to 170°. More preferably, the inclination angle α of the third edge 726 may be within a range of 120 to 160°.

[0032] As shown in FIG. 4B , the presser plate 72 has a mounting surface 729 for mounting the first articulated robot 70 and a pressing surface 728 for pressing the packing paper 300. Also, as shown in FIG. 4C , the first inclined edge portion 722, the tip portion 723, and the second inclined edge portion 724 each have a tapered surface 730 formed at their end so that the pressing surface 728 is spaced apart from the packing paper 300. That is, the tapered surface 730 is formed so that the thickness of the presser plate 72 gradually decreases toward the end at each of the first inclined edge portion 722, the tip portion 723, and the second inclined edge portion 724. The chamfer on the pressing surface 728 that contacts the packing paper 300 may be a simple chamfer rather than a tapered surface 730. In this case, the chamfer dimension may be approximately 2 to 5 mm. The thickness of the presser plate 72 may be set appropriately taking into account weight and strength, but is preferably approximately 3 to 10 mm, for example.

[0033] The presser plate 72 has suction pads 727 for adsorbing the packing paper to the pressing surface 728. In the example of Fig. 4, two suction pads 727 are provided on the side opposite the tip end 723 in the traveling direction (the side closer to the third edge 726), but the number of suction pads 727 is not limited to two, and the positions at which they are provided are not limited to these positions.

[0034] 5A, 5B, and 5C are diagrams showing the state of the metal strip coil 200 up to the coil packaging stage. Fig. 5A shows the metal strip coil 200 in a state where no packing paper is wrapped around it. Reference numeral 201 denotes an axial end face. In this specification, "coil packaging" refers to packaging a metal strip coil such as a steel sheet coil in packing paper (to produce a packaged metal strip coil) in order to maintain quality in a factory or warehouse before shipping the product and to prevent damage during transportation.

[0035] Figure 5B shows a state in which a strip-shaped packing paper is wound around the outer periphery of the metal strip coil 200. Reference numeral 301 denotes an end surface covering portion of the packing paper 300. In the state shown in Figure 5B, (1) the mountain folds ("pleats") of the end surface covering portion 301 are folded along the circumferential direction of the metal strip coil 200, and each time the mountain folds are secured with adhesive tape, and the same operation is performed for the entire end surface covering portion of the packing paper 300. The edge folding device of this embodiment automatically performs the operation (1). Then, (2) the mountain folds protruding toward the inner diameter side of the metal strip coil 200 are pushed into the inside of the coil hole and secured, resulting in the "coil packaging" state shown in Figure 5C.

[0036] As shown in Figure 5C, in the packed metal strip coil state, the metal strip coil is wrapped in strip-shaped packing paper (packaging material) and the leading and trailing ends are fixed. The metal strip coil has a "chrysanthemum fold" shape with multiple pleats woven into the axial end face of the metal strip coil, and the "pleats" that protrude to the inner diameter side of the metal strip coil are stored inside the metal strip coil hole.

[0037] Next, a description will be given of the edge folding operation performed by the edge folding device 100 of this embodiment. The control unit 20 executes a predetermined operation program to control the operation of each of the first articulated robot 70 and the second articulated robot 80, thereby performing the edge folding operation on the packing paper 300.

[0038] FIG. 6 illustrates the first operation of the first articulated robot 70 and the second articulated robot 80. The control unit 20 controls the first articulated robot 70 to press the folding portion of the end surface covering portion 301 of the packing paper against the axial end surface 201 of the metal strip coil with the pressure plate 72. In this case, the pressure plate 72 moves in the direction indicated by symbol C1 in FIG. 6. In this embodiment, the pressing operation against the packing paper is performed using force control to prevent overloading of the first articulated robot 70 and the second articulated robot 80, damage to the packing paper, and scratches on the side of the metal strip coil. For example, the torque value at a specified joint of the robot is controlled so as not to exceed an upper limit. The first operation allows the folding portion to be pressed tightly against the side of the metal strip coil.

[0039] 7 is a diagram showing the second operation of the first articulated robot 70 and the second articulated robot 80. The control unit 20 controls the second articulated robot 80 so that the grippers 811, 812 (81) grip the end of the folded portion of the packing paper. In this case, the folding portion is pressed against the axial end surface 201 of the metal strip coil by the presser plate 72. The end of the packing paper is gripped by the second operation.

[0040] 8 is a diagram showing a third operation of the first articulated robot 70 and the second articulated robot 80. The control unit 20 controls the first articulated robot 70 to move the pressure plate 72 to the position of the valley fold line of the folded portion of the packing paper (moving along the direction indicated by symbol C2 in FIG. 8 ) so that the first edge portion 721 of the pressure plate 72 is aligned with the valley fold line, and the pressure plate 72 presses the packing paper against the axial end surface 201 of the metal strip coil at the position of the valley fold line. Through the third operation, the valley fold line of the packing paper can be positioned and the position of the valley fold line can be maintained.

[0041] FIG. 9 is a diagram showing the fourth operation of the first articulated robot 70 and the second articulated robot 80. The control unit 20 controls the first articulated robot 70 and the second articulated robot 80 to move the gripper 81 (moving in the direction indicated by symbol C3 in FIG. 9 ) to a position opposite the valley fold line while gripping the end of the fold portion of the packing paper with the gripper 81, and fold the packing paper. In this embodiment, the folding operation is performed by grippers 811 and 812 equipped with force control and a spring mechanism to perform the folding operation with a constant tension regardless of the packing paper material and to prevent overloading of the robot. The fourth operation allows the mountain fold line of the fold portion to be formed as the fold portion gripped by the gripper 81 is folded.

[0042] Here, stabilization of the pleat shape will be described.

[0043] Figure 10 shows an example of a comparative example in which the pleats are poorly shaped. As shown in Figure 10, the inner cylindrical surface of the coil is hollow, so the packing paper inside the coil inner diameter (closer to the center) can move freely in and out of the coil. As a result, the pleats inside the coil cannot be pressed down during the edge folding operation, resulting in poorly shaped pleats.

[0044] A method for stabilizing the pleat shape according to this embodiment will now be described. Figures 11, 12, 13, and 14 are diagrams showing an example of the pleat shape stabilization procedure. First, as shown in Figure 11, the packing paper is sucked by the suction pad 727, the pressure plate 72 holds the packing paper, and the gripper 81 grips the packing paper. Next, as shown in Figure 12, with the packing paper still sucked by the suction pad 727, the gripper 81 grips the packing paper and moves the gripper 81 to above the valley fold line. Next, as shown in Figure 13, the suction by the suction pad 727 is released, and the pressure plate 72 moves in the direction of the arrow along the valley fold line to a position where it does not interfere with the gripper 81. Finally, with the packing paper still gripped by the gripper 81, the gripper 81 moves in the direction of the arrow to the mountain fold line.

[0045] 15 is a diagram showing an example of the pleat shape formed by the presser plate 72 of this embodiment. As described above, according to this embodiment, when the fold-in portion gripped by the gripper 81 is folded to form the mountain fold line of the fold-in portion, the presser plate 72 having the suction pad 727 sucks and presses the packing paper with the suction pad 727, which prevents the packing paper from moving freely in the hollow portion inside the inner diameter of the coil, thereby forming a good pleat shape.

[0046] Figure 16 is a diagram showing the fifth operation of the first articulated robot 70 and the second articulated robot 80. The control unit 20 controls the first articulated robot 70 to move the pressure plate 72 in accordance with the valley fold line of the packing paper (moving along the direction indicated by symbol C4 in Figure 16). At this time, the fold portion gripped by the gripper 81 is held slightly away from the axial end face and axially outward from the pressure plate 72. By the fifth operation, the valley fold line can be formed and the fold portion can be folded along the valley fold line.

[0047] Here, we will explain how to prevent the packaging paper from tearing.

[0048] 17 and 18 are diagrams showing an example of a comparative example in which tearing of packing paper occurs. As shown in Fig. 17, the comparative example pressure plate is rectangular (oblong), and the four corners of the pressure plate are slightly rounded. Suppose the pressure plate shown in Fig. 17 is moved in the direction of the arrow along the valley fold line. In this case, as shown in Fig. 18, the corners of the pressure plate may catch on the packing paper, causing a tear when the valley fold line is formed.

[0049] 19 is a diagram showing an example of the formation of a valley fold line by the presser plate 72 of this embodiment. The presser plate 72 of this embodiment has a first inclined edge 722, which eliminates the corners of the presser plate 72, preventing the corners from getting caught on the packing paper, as in the comparative example. This makes it possible to form a valley fold line without tearing the packing paper.

[0050] The angle θ between the first edge 721 and the first inclined edge 722 can be 3 to 20 degrees. If the angle θ is less than 3 degrees, the packing paper may get caught. If the angle θ is more than 20 degrees, the packing paper may not be pressed down sufficiently all the way to the outermost periphery of the coil 200.

[0051] The tip 723 is convexly curved with a radius of curvature in the range of 2 to 15 mm. If the radius of curvature is less than 2 mm or more than 15 mm, it may get caught on the packing paper. The distance between the extension line of the first edge 721 and the tip 723 can be 5 to 20 mm. If this distance is less than 5 mm, it may get caught on the packing paper. If this distance is more than 20 mm, it may not be possible to sufficiently press the packing paper down to the outermost periphery of the coil 200.

[0052] Next, a method for preventing collision with wrinkles in the packing paper will be described.

[0053] Figure 20 shows an example of a comparative example where a collision occurs with wrinkles in the packing paper. There are wrinkles of various sizes on the end surface covering portion 301 of the packing paper 300. As shown in Figure 20, when the pressing surface of the pressure plate and the leading edge in the traveling direction are perpendicular to each other, if the pressure plate is moved in the direction of the arrow while pressing down on the packing paper with the pressure plate, the leading edge of the pressure plate can get caught on wrinkles or small protrusions that have occurred in the packing paper, causing the packing paper to tear or stopping the operation.

[0054] 21 is a diagram showing an example of the state of the pressure plate 72 of this embodiment as it moves. When the pressure plate 72 is moved while pressing down on the packing paper to form valley folds and mountain folds during edge folding or to smooth out wrinkles, the pressure plate 72 of this embodiment has a tapered surface 730 (the side of the pressing surface 728 that contacts the packing paper 300 is chamfered), so it does not get caught on wrinkles or small protrusions that have developed in the packing paper. This prevents collisions with wrinkles, tearing the packing paper, and work stoppages.

[0055] Next, a method for preventing collision with the miswinding of the outermost periphery of the coil (metal band coil) 200 will be described.

[0056] Fig. 22 is a diagram showing an example of winding deviation at the outermost periphery of the coil 200. When winding a metal strip into a coil, winding deviation is likely to occur at the outermost periphery of the coil, and as shown in Fig. 22, a part of the coil 200 may protrude outward in a convex shape from the end face of the coil 200.

[0057] 23 is a diagram showing an example of a comparative example in which a rectangular pressure plate collides with the outermost periphery of coil 200. As shown in Fig. 23, when the rectangular pressure plate is moved along the valley fold line, the leading end of the pressure plate on the opposite side from the valley fold line collides with the miswinding of the outermost periphery before the leading end of the pressure plate on the valley fold line side reaches the outermost periphery. For this reason, with the rectangular pressure plate, the valley fold line cannot be formed sufficiently all the way to the outermost periphery of coil 200.

[0058] 24 is a diagram showing an example of how the presser plate 72 of this embodiment prevents collision with the misaligned winding of the outermost periphery of the coil 200. In the presser plate 72 of this embodiment, the second inclined edge 724 connects the tip 723 to the second edge 725 facing the first edge 721, and the connection portion 731 between the second edge 725 and the second inclined edge 724 is set to be located away from the outermost periphery when the presser plate is moved in alignment with the valley fold line until the tip 723 abuts against the outermost periphery of the coil 200 to form the fold. As a result, when the presser plate 72 is moved, even if the tip 723 of the presser plate 72 reaches the outermost periphery of the coil 200, the connection portion 731 is located away from the outermost periphery, so the second inclined edge 724 does not collide with the misaligned winding of the outermost periphery, and the presser plate 72 does not collide with the misaligned winding of the outermost periphery. This prevents work stoppages and allows valley fold lines to be formed sufficiently all the way to the outermost periphery of coil 200. The position of connection 731 between second edge 725 and second inclined edge 724 can be set according to the outer diameter of coil 200 to be packed. When the outer diameter of coil 200 is small, connection 731 needs to be recessed farther rearward in the direction of travel, based on the position of tip 723. On the other hand, when the outer diameter of coil 200 is large, connection 731 may be recessed farther rearward.

[0059] FIG. 25 illustrates a sixth operation of the first articulated robot 70 and the second articulated robot 80. The control unit 20 controls the first articulated robot 70 to move the pressure plate 72 along the mountain fold (mountain fold line) while pressing it against the mountain fold of the fold. During this operation, with the gripper 81 gripping the end of the fold of the packing paper, the pressure plate 72 is temporarily released from the axial end surface 201 of the metal strip coil. Then, the pressure plate 72 is moved along the mountain fold line in the direction indicated by the symbol C5 while again pressing the fold from above the mountain fold line of the fold gripped by the gripper 81 against the axial end surface. The sixth operation allows the mountain fold to be folded along the mountain fold line. Furthermore, the crease of the fold can be emphasized.

[0060] Here, a method for preventing wrinkles that occur when folding the packaging paper will be described.

[0061] 26 and 27 are diagrams showing an example of the flow of wrinkles as a comparative example. In the case of the pressure plate as a comparative example shown in Fig. 26, when the pressure plate is moved, the wrinkles in the packing paper flow in a direction perpendicular (perpendicular to) the movement direction (advancement direction) of the pressure plate, causing the wrinkles to collide with the pressure plate. This can result in large wrinkles, as shown in Fig. 27.

[0062] Figure 28 is a diagram showing an example of how wrinkles are smoothed by the presser plate 72 of this embodiment. In the presser plate 72 of this embodiment, the third edge 726 has a convex shape that is symmetrical in the direction opposite to the direction of travel, and is rounded at the center and both ends. As shown in Figure 28, when the presser plate 72 is moved in the direction of the arrow, the angle between the direction of wrinkle flow and the movement direction (direction of travel) is less than 90°, so that the third edge 726 smooths out the wrinkles as the presser plate 72 moves. This prevents large wrinkles from occurring and effectively smooths out the wrinkles.

[0063] FIG. 29 shows the seventh operation of the first articulated robot 70 and the second articulated robot 80. The control unit 20 controls the second articulated robot 80 to apply adhesive tape across the edge of the mountain fold to secure the folded portion. In this case, the presser plate 72 holds down the folded mountain fold, and the application unit 713 applies adhesive tape cut to the required size. Furthermore, applying the adhesive tape under tension while gripping the packing paper can prevent the packing paper from bulging overall. The seventh operation secures the mountain fold (the pleat).

[0064] The control unit 20 repeats the series of operations (edge ​​folding operations) from the first operation to the seventh operation described above a predetermined number of times along the circumferential direction of the metal strip coil. As a result, when the edge folding operation for half the circumference of the metal strip coil is completed, the robot table 32 is rotated 180 degrees to reverse the positional relationship between the first articulated robot 70 and the second articulated robot 80 and the metal strip coil, and the edge folding operations from the first operation to the seventh operation are performed for the remaining half circumference, thereby completing the edge folding operation for the entire circumference of the metal strip coil. Note that instead of rotating the robot table 32 180 degrees, the metal strip coil itself may be rotated by a cradle roll.

[0065] The embodiments disclosed above should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined not by the above embodiments but by the claims, and is intended to include all modifications and variations within the meaning and scope of the claims.

[0066] For example, the convex shape that is asymmetrical left and right with respect to the direction of travel of the outer edge does not have to be formed by having a first inclined edge portion and a second inclined edge portion, but may be an asymmetrical shape that is curved as a whole, or a portion of the part extending from the tip portion to the first edge portion and the second edge portion may have a concave shape.

[0067] (Appendix 1) The pressure plate is attached to the tip of the arm of a multi-joint robot equipped in an edge folding device that folds the edge of an end surface covering portion, which is part of the packaging material that packs a metal strip coil and covers the axial end surface of the metal strip coil, and is used to press the end surface covering portion against the axial end surface of the metal strip coil.The outer edge of the portion that is at the front in the traveling direction, which is the direction in which the pressure plate is moved when forming a valley fold in the packaging material, is chamfered on the side of the pressing surface that contacts the packaging material, and is suitable for smoothly forming the fold up to the vicinity of the outermost periphery of the metal strip coil without damaging the packaging material when forming the valley fold.In addition, when viewed in a plane, the pressure plate has a convex shape that is asymmetrical with respect to the traveling direction so that no part other than the tip in the traveling direction reaches the outermost periphery of the metal strip coil, and all apexes, including the tip, are rounded.

[0068] (Appendix 2) In Appendix 1, the pressure plate has a first inclined edge portion and a second inclined edge portion with the tip portion between them, the first inclined edge portion extends from a first edge portion that is positioned along the valley fold line when the pressure plate is moved in line with the valley fold line of the packaging material to form the fold, and is inclined away from the valley fold line, the second inclined edge portion connects the tip portion to a second edge portion opposite the first edge portion, and the connection portion between the second edge portion and the second inclined edge portion is set to be in a position away from the outermost portion when the pressure plate is moved in line with the valley fold line until the tip portion abuts the outermost portion of the metal strip coil to form the fold.

[0069] (Appendix 3) In Appendix 2, the pressure plate has a third edge portion connected to the first edge portion and the second edge portion on the opposite side to the leading side in the traveling direction, and the third edge portion has a convex shape that is symmetrical in the direction opposite to the traveling direction, and is rounded at the center and both ends.

[0070] (Supplementary Note 4) In any one of Supplementary Notes 1 to 3, the pressing plate has a suction pad for adsorbing the packaging material onto the pressing surface.

[0071] (Supplementary Note 5) In the presser plate according to any one of Supplementary Notes 1 to 4, the radius of curvature of the rounded tip portion is within a range of 2 to 15 mm.

[0072] (Supplementary Note 6) In any one of Supplementary Notes 1 to 5, the pressing plate has an angle formed between the first edge and the first inclined edge within a range of 3 to 20 degrees.

[0073] (Supplementary Note 7) In any one of Supplementary Notes 1 to 6, the pressing plate has a dimension between an extension line of the first edge portion and the apex of the tip portion within a range of 5 to 20 mm.

[0074] (Appendix 8) The edge folding device is an edge folding device that folds the edge of the end surface covering portion, which is part of the packaging material that packs the metal strip coil and covers the axial end surface of the metal strip coil, and is equipped with a multi-joint robot with the aforementioned pressure plate attached to the tip of the arm.

[0075] The features described in each embodiment can be combined with each other. In addition, independent claims and dependent claims described in the claims can be combined with each other in any and all combinations regardless of the form of reference, as long as they do not involve mutually exclusive requirements.

[0076] DESCRIPTION OF SYMBOLS 10 Relative position detection unit 20 Control unit 70 First articulated robot 71 First end effector 72 Pressing plate 721 First edge portion 722 First inclined edge portion 723 Tip portion 724 Second inclined edge portion 725 Second edge portion 726 Third edge portion 727 Suction pad 728 Pressing surface 729 Mounting surface 730 Tapered surface 713 Sticking portion 714 Roll portion 80 Second articulated robot 81 Second end effector (gripper) 811, 812 Gripper (gripper) 90 Robot portion 200 Metal strip coil 201 Axial end surface 300 Packing paper 301 End surface covering portion

Claims

1. A pressure plate attached to the end of an arm of an articulated robot equipped in an edge folding device that folds the edges of an end covering part, which is part of a packaging material for packaging a metal strip coil and covers the axial end face of the metal strip coil, for pressing the end covering part against the axial end face of the metal strip coil, wherein the outer edge of the part that is the leading side in the traveling direction, which is the direction in which the pressure plate is moved when forming a valley fold in the packaging material, is chamfered on the side of the pressing surface that comes into contact with the packaging material, and is suitable for smoothly forming the fold up to the vicinity of the outermost circumference of the metal strip coil without damaging the packaging material when forming the valley fold, and has a convex shape that is asymmetrical with respect to the traveling direction in a plan view so that there is no part other than the tip in the traveling direction that reaches the outermost circumference of the metal strip coil, and all apexes including the tip are rounded.

2. The pressure plate according to claim 1, wherein the pressure plate has a first inclined edge and a second inclined edge with the tip portion between them, the first inclined edge extends from a first edge which is positioned along the valley fold line when the pressure plate is moved in line with the valley fold line of the packaging material to form the fold, and is inclined away from the valley fold line, the second inclined edge connects the pressure plate to a second edge opposite the first edge and the tip portion, and the connection portion between the second edge and the second inclined edge is set to be in a position away from the outermost portion when the pressure plate is moved in line with the valley fold line until the tip portion abuts the outermost portion of the metal strip coil to form the fold.

3. A pressure plate as described in claim 2, further comprising a third edge portion connected to the first edge portion and the second edge portion on the opposite side to the leading side in the traveling direction, the third edge portion having a convex shape that is symmetrical in the direction opposite to the traveling direction, and a radius is added to the center and both ends.

4. The pressing plate according to any one of claims 1 to 3, further comprising an adsorption pad for adsorbing the packaging material to the pressing surface.

5. A pressing plate as set forth in any one of claims 1 to 3, wherein the radius of curvature of the curved tip is within a range of 2 to 15 mm.

6. A pressure plate as described in claim 2 or claim 3, wherein the angle between said first edge portion and said first inclined edge portion is within the range of 3 to 20 degrees.

7. A pressing plate as claimed in claim 2 or 3, wherein the dimension between the extension line of said first edge portion and the apex of said tip portion is within the range of 5 to 20 mm.

8. An edge folding device for folding the edge of an end surface covering portion, which is part of a packaging material for packaging a metal strip coil and covers the axial end surface of the metal strip coil, comprising a multi-joint robot having a pressure plate described in any one of claims 1 to 3 attached to the tip of its arm.

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