Box opening device and box opening method

Abstract

To provide a box opening apparatus and a box opening method capable of reducing a box opening failure caused by a tape cutting error.SOLUTION: An opening apparatus 11 cuts tapes 17 and 18 affixed to an opening surface of a box 12 to open the box 12. The opening apparatus includes a height detection device 30 for detecting a position of the tape in an intersecting direction that intersects the opening surface of the box 12 to which the tape is affixed, and a robot 40. A camera 50 and a cutter 53 are attached to a head 44 mounted on a tip of an arm 43 of the robot 40. The camera 50 captures an image of an opening surface 13 from the intersecting direction to obtain a captured image including the opening surface 13. The cutter 53 moves relative to the box 12 and cuts the tapes 17 and 18. A control unit controls a position of the cutter 53 to cut the tapes 17 and 18 along a cutting path of the tapes 17 and 18 determined according to the position in a height direction Z of the tapes 17 and 18 detected by the height detection device 30, and the position of contour of the opening surface in the captured image.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a box opening device and a box opening method that cut a tape attached to a box to open the box. [Background technology]

[0002] For example, Patent Documents 1 to 3 disclose a box opening device that cuts the tape attached along the periphery of the closed flaps of the box to open the box. The box opening device (opening device) described in Patent Document 1 uses a cutter to cut the adhesive tape attached to the abutment parts of the flaps of a cardboard box to open the box.

[0003] Furthermore, the box-opening devices described in Patent Documents 2 and 3 are equipped with a horizontally supported guide plate and a cutter erected on the guide plate, and the guide plate is inserted inside the flap of the box to lift the flap slightly, and the box is transported on a conveyor, whereby the tape is cut by the cutter and the box is opened. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-124015 [Patent Document 2] Japanese Patent Publication No. 59-152133 [Patent Document 3] Japanese Patent Application Publication No. 11-91746 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the opening devices described in Patent Documents 1 to 3, if the cutter is inserted too shallowly into the tape or the cutter separates from the tape due to variations in the height of the top surface (opening surface) of the box, the tape is not cut in parts, resulting in defective opening of the box. Conversely, if the cutter is inserted too deeply, there is a risk that the contents of the box may be damaged. For this reason, there is a demand for a box opening device that can reduce defective opening of boxes caused by incorrect cutting of the tape, even if there is some variation in the height of the top surface (opening surface) of the box.

[0006] An object of the present invention is to provide a box opening device and a box opening method that can reduce defects in opening a box caused by incorrect cutting of the tape. [Means for solving the problem]

[0007] The means for solving the above problems and their effects will be described below. The box opening device that solves the above problem is a box opening device that cuts a tape attached along the periphery of a flap that closes an opening of a box to open the box, and includes a position detection unit that detects the position of the tape in a cross direction that crosses the opening surface of the box to which the tape is attached, an imaging unit that captures the opening surface from an imaging position away from the cross direction to obtain an image including the opening surface, a cutter that moves relative to the box to cut the tape, and a control unit that cuts the tape by controlling the position of the cutter along the cutting path of the tape in a control coordinate system that is determined based on the position of the tape in the cross direction detected by the position detection unit and the cutting path of the tape in an image coordinate system determined from the position of the outline of the opening surface in the captured image. Note that the position of the outline of the opening surface in the captured image is not limited to the position of the entire circumference of the outline, and may be at least a part of the outline where the cutting path of the tape can be specified. For example, if the outline is a polygon, it may be the position of at least two vertices of the outline.

[0008] According to this configuration, the cutting path is determined based on the position of the tape in the cross direction intersecting with the opening surface and the position of the outline of the opening surface in the captured image of the opening surface, so that even if the position of the tape varies slightly in the cross direction, the cutter can be appropriately positioned relative to the tape. Therefore, it is possible to reduce defects in opening the box caused by incorrect cutting of the tape attached to the opening surface of the box.

[0009] In the above-mentioned box opening device, the position detection unit may have a sensor unit that is movable in the intersecting direction while emitting detection light in a direction parallel to the opening surface of the box, and a first moving mechanism that moves the sensor unit in the intersecting direction, and may be provided with a second moving mechanism that moves the sensor unit in the intersecting direction to detect the position of the tape in the intersecting direction and moves the imaging unit to the imaging position.

[0010] With this configuration, the position detection in the cross direction of the tape and the imaging of the opening surface can be performed in parallel by independent moving mechanisms. Compared to a configuration in which the position detection unit and the imaging unit are controlled by the same moving mechanism, the cutting path of the cutter can be determined quickly and the tape can be cut at high speed.

[0011] The above-mentioned box opening device may be provided with a distance sensor that measures the distance to the tape in the cross direction, and the control unit may cause the distance sensor to detect multiple distances to the tape along the cutting path of the tape, and may control the position of the cutter in the cross direction in accordance with changes in the distance to the tape during the process of cutting the tape by controlling the position of the cutter along the cutting path.

[0012] With this configuration, the tape can be cut so as to follow the indentation on the opening surface of the box. In the above-mentioned box opening device, the second moving mechanism is a multi-joint robot having an arm to the tip of which the imaging unit and the cutter are attached and which is controlled by the control unit, and the distance sensor may be attached to the tip of the arm.

[0013] According to this configuration, a distance sensor is also attached to the arm of the robot that controls the position of the cutter, so that the change in distance to the tape in the cross direction can be measured along the cutting path, so that the tape can be cut following the indentation on the opening surface of the box.

[0014] In the above-mentioned box opening device, the position detection unit is a distance sensor that measures the distance to the tape in the cross direction and detects the position of the tape in the cross direction, and the control unit may cause the distance sensor to detect multiple distances to the tape along the cutting path of the tape, and control the position of the cutter in the cross direction in accordance with changes in the distance to the tape during the process of cutting the tape by controlling the position of the cutter along the cutting path.

[0015] With this configuration, the tape can be cut so as to follow the indentation on the opening surface of the box. In the above-mentioned box opening device, the imaging unit may be fixed at a predetermined height position where the opening surface of the box can be imaged, and may include an articulated robot having an arm to the tip of which the cutter is attached and controlled by the control unit, and a lifting mechanism that raises or lowers the box until it reaches a height position where the opening surface of the box becomes the focus of the imaging unit.

[0016] With this configuration, there is no need to move the imaging unit. Also, if the lifting mechanism is set so that the imaging unit focuses on the opening surface of the box when the opening surface is at a height position where the movable range of the arm with the cutter attached to its tip is wide, the maximum size of the box that the cutter can cut the tape through can be increased.

[0017] The above-mentioned box opening device may further include a transport mechanism that transports the box horizontally along the longitudinal direction of the tape, and when a portion of the tape is within the movable area of ​​the cutter and another portion of the tape is not within the movable area, the control unit may cut the portion of the tape with the cutter, and cut the other portion of the tape with the cutter accompanied by a transport operation that transports the box horizontally until the other portion of the tape is positioned at a cutting position within the movable area.

[0018] With this configuration, even if a box is large enough that part of the tape is within the movable range of the cutter attached to the tip of the arm and another part of the tape is outside the movable range of the cutter, the tape can be cut by transporting the box horizontally. This increases the maximum size of the box that can be cut relative to the movable range of the robot's arm.

[0019] In the above-mentioned box opening device, the control unit may control the inclination angle of the cutter relative to the surface of the tape so that it falls within an acceptable range in accordance with changes in the distance to the tape during the process in which the cutter cuts the tape.

[0020] According to this configuration, the cutter is controlled to be positioned along the cutting path and the inclination angle of the cutter relative to the tape surface is controlled to be within an allowable range during the process of cutting the tape, so the load on the cutter when cutting the tape can be reduced, which can reduce damage to the cutter and extend its lifespan.

[0021] In the above-mentioned box opening device, a first tape attached to the boundary between the two flaps on the opening surface of the box and a second tape attached along the boundary between the two flaps and the side of the box are to be cut, and the control unit may determine a cutting path for the first tape from the position in the intersecting direction and position coordinates of an image coordinate system of multiple points including two or more vertices in the outline of the opening surface in the captured image, cut the first tape by controlling the position of the cutter along the determined cutting path, and determine an edge line from the position in the intersecting direction and an image coordinate system edge line where the opening surface and an adjacent surface in the captured image intersect, and cut the second tape by controlling the position of the cutter along the cutting path along the determined edge line.

[0022] With this configuration, the cutter is position-controlled along a cutting path that follows the edge line where the opening surface and side of the box intersect, so that even if the side of the box is deformed, the second tape can be cut along the curved edge line caused by the deformation.

[0023] The method for opening a box that solves the above problem is a method for opening a box by cutting a tape attached along the periphery of a flap that closes an opening of the box, and includes a position detection step for detecting the position of the tape in a cross direction crossing the opening surface of the box to which the tape is attached, an imaging step for imaging the opening surface of the box to obtain an image, and a control step for controlling the position of a cutter along a cutting path of the tape that is determined based on the position of the tape in the cross direction detected in the position detection step and the cutting path of the image coordinate system of the tape that is determined from the outer position of the opening surface in the image obtained in the imaging step. According to this method, like the box opening device, it is possible to reduce defective opening of the box caused by incorrect cutting of the tape. Effect of the Invention

[0024] According to the present invention, defects in opening a box caused by incorrect cutting of the tape can be reduced. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a schematic side view showing a box opening system according to a first embodiment. [Diagram 2] FIG. 1 is a schematic front view showing a box opening system. [Diagram 3] FIG. 1 is a perspective view showing a box positioned in a working position. [Figure 4] FIG. 2 is a block diagram showing the electrical configuration of the box opening system. [Diagram 5] Schematic diagram for explaining a method for determining a cutting path from the outline of the opening surface of a box. [Figure 6] 5A to 5C are schematic diagrams illustrating a method for determining a cutting path for the second tape. [Figure 7] 6 is a schematic plan view illustrating the operation of a cutter for cutting the second tape. FIG. [Figure 8] 11 is a flowchart showing tape cutting control. [Figure 9] 13A is a schematic front view showing a modified example of the height detection device, and FIG. 13B is a schematic front view showing a portion of the first tape attached to the flap. [Figure 10] FIG. 11 is a schematic front view showing tape cutting control in the second embodiment. [Figure 11] 11 is a flowchart showing tape cutting control. [Figure 12] FIG. 13 is a front view showing a box opening system according to a third embodiment. [Figure 13] FIG. 13 is a side view showing the opening device when opening a large-sized box. [Figure 14] FIG. 13 is a side view showing the opening device when opening a small-sized box. [Figure 15] FIG. 4 is a schematic side view, partly broken away, showing the head attached to the arm. [Figure 16] FIG. 4 is a schematic front view showing a head attached to an arm. [Figure 17] FIG. 4 is a schematic front view showing how a distance sensor measures a distance in the vertical direction Z. [Figure 18] FIG. 11 is a schematic front view showing a state in which the first tape is cut. [Figure 19] 13 is a schematic front view illustrating the operation of the cutter for cutting the second tape for a large-sized box. FIG. [Figure 20] 11 is a flowchart showing tape cutting control. [Figure 21] FIG. 13 is a schematic front view showing tape cutting control by a head of a comparative example in a modified example. [Figure 22] FIG. 4 is a schematic front view showing tape cutting control by the head of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] An embodiment of a box opening system 10 including a box opening device 11 will be described below with reference to the drawings. In the box opening system 10 shown in Fig. 1 and Fig. 2, the height direction of the box 12 is the Z direction, the direction parallel to the conveying direction in which the box 12 is conveyed among two directions perpendicular to the Z direction is the X direction, and the width direction perpendicular to the X direction is the Y direction. Note that the direction in which the box 12 is conveyed among the X directions is also referred to as the conveying direction X1, and the two directions Y and Z are also referred to as the width direction Y and the height direction Z.

[0027] 1 and 2 includes a transport device 20 having a conveyor 21 for transporting boxes 12, and a box opening device 11 for performing an opening operation to open the box 12 by cutting tapes 17, 18 on the box 12 positioned at a work position SP on the conveyor 21. In the example shown in Fig. 1, the box 12 is placed on the conveyor 21 and transported with the opening surface 13 to be opened facing up. The opening device 11 cuts the tapes 17, 18 attached to the opening surface 13 of the box 12 with a cutter 53 to open the box 12.

[0028] As shown in FIGS. 1 and 2, the conveying device 20 includes a positioning device 22 that positions the box 12 on the conveyor 21 at a work position SP. The positioning device 22 includes a stopper device 23 that positions the box 12 in the conveying direction X1, and a pair of guide devices 24 that positions the box 12 in the width direction Y intersecting with the conveying direction X1. The stopper device 23 includes a cylinder 25 and a stopper 26 fixed to the tip of the piston rod of the cylinder 25. When the cylinder 25 is in a contracted state, the stopper 26 is disposed at a retracted position below the conveyor 21, and when the cylinder 25 is driven to extend, the stopper 26 is disposed at a restricting position that protrudes above the conveyor 21 and restricts the movement of the box 12 in the conveying direction X1 to position the box 12 in the conveying direction X1.

[0029] 1 and 2, the pair of guide devices 24 are arranged on both sides of the work position SP on the conveyor 21 in the width direction Y, and have a pair of cylinders 27 and a guide member 28 fixed to the tip of the piston rod of the cylinder 27. When the pair of cylinders 27 are both driven to extend, the pair of guide members 28 sandwich the box 12 from both sides to position the box 12 in the width direction Y. The pair of guide devices 24 are driven when a sensor 29 shown in FIG. 2 detects the box 12 positioned in the conveying direction X1 by the stopper device 23, and position the box 12 in the width direction Y.

[0030] As shown in Figure 1, the opening device 11 includes a height detection device 30 that detects the height position of the opening surface 13 of the box 12 positioned at the work position SP, and a robot 40 that performs cutting work to cut the tapes 17, 18 attached to the opening surface 13 at the detected height position.

[0031] The height detection device 30 detects the height position of the opening surface 13, which is the top surface of the box 12. The height detection device 30 includes a lifting mechanism 31 and a sensor unit 32 supported by the lifting mechanism 31 so as to be movable (lifted) in the height direction Z. The sensor unit 32 includes a detection unit 33 having a light emission function of emitting detection light HL, shown by a dashed line in FIG. 1, in a horizontal direction toward above the work position SP, and a light receiving function of receiving the detection light HL reflected by an object on the light emission path. The lifting mechanism 31 includes a rail 34 having a predetermined length extending in the height direction Z, and a motor 35 serving as a power source for raising and lowering the sensor unit 32 in the height direction Z along the rail 34. The sensor unit 32 moves in the height direction Z along the rail 34 by transmitting the power of the motor 35 via a power transmission mechanism (not shown). The power transmission mechanism is, for example, one of a belt type, a wire type, and a ball screw type. Moreover, the power source of the lifting mechanism 31 may be an electric cylinder instead of the motor 35 .

[0032] As shown in FIG. 1, the sensor unit 32 of the height detection device 30 moves (rises and falls) in the height direction Z while emitting detection light HL in a direction parallel to the opening surface 13 of the box 12. The sensor unit 32 is, for example, a laser scanner that emits laser light as the detection light HL. The sensor unit 32 detects a switching position between a state in which the detection unit 33 does not detect an object and a state in which the detection unit 33 detects an object as a height position of the opening surface 13 of the box 12 during the process of moving in the height direction Z. That is, the height detection device 30 detects the height position of the opening surface 13 of the box 12 based on the presence or absence of reflected light of the detection light HL emitted from the sensor unit 32 moving in the height direction Z. For example, the sensor unit 32 emits detection light HL in the horizontal direction while descending at a predetermined speed from a predetermined detection start position higher than the expected height of the box 12, and when it begins to receive reflected light from the box 12, detects the height position at that time as the height position of the opening surface 13. In this way, the height detection device 30 detects the height position of the opening surface 13 of the box 12 to be opened by the robot 40. If the opening surface 13 is a horizontal plane, the height position of this opening surface will be the height position of the tapes 17, 18 attached to the opening surface 13. Furthermore, the height direction Z is a direction intersecting (e.g. perpendicular to) the opening surface 13. In this regard, the height detection device 30 detects the positions of the tapes 17, 18 in a direction intersecting the opening surface 13 of the box 12 to which the tapes 17, 18 are attached. Note that the height detection method of the height detection device 30 is not limited to a light detection method of emitting detection light HL and detecting the reflected light, and may be a method of detecting the height of the opening surface 13 using sound waves.

[0033] As shown in FIG. 1, the robot 40 is an articulated industrial robot including a base 41 installed on a floor surface, a rotating base 42 rotatable around a vertical axis relative to the base 41, an articulated arm 43 supported by the rotating base 42, and a head 44 supported at the tip of the arm 43. The arm 43 rotates about its axis together with the rotating base 42 by the power of a power source 45 arranged on the base 41. The arm 43 is composed of a plurality of arm parts 43A to 43D connected so that the angle can be changed. The angles of the plurality of arm parts 43A to 43D are adjusted via a drive link or the like (not shown) by driving a drive mechanism 46. The drive mechanism 46 includes a power source (not shown) such as an electric motor or an electric cylinder. The head 44 is supported by a rotating part 48 in which the arm part 43D, which is the tip of the arm 43, is provided with an unillustrated motor as a power source so as to be rotatable about its axis. The head 44 is detachably attached to the rotating part 48 of the arm part 43D. Thus, the robot 40 of this embodiment is a six- or seven-axis articulated robot that includes six or seven joints each made up of the rotating table 42 and the multiple arm sections 43A to 43D.

[0034] As shown in FIG. 1 and FIG. 2, the head 44 has a support part 49 supported by a rotating part 48. A camera 50 as an example of an imaging part and a cutter unit 51 are attached to the support part 49. The robot 40 moves the camera 50 to an imaging position shown in FIG. 1 and FIG. 2 where the camera 50 is focused at the height position detected by the sensor part 32, and images the opening surface 13 of the box 12 with the camera 50. The imaging position is set at a position above the opening surface 13 by a predetermined height in the height direction Z perpendicular to the opening surface 13 of the box 12 positioned at the work position SP. The camera 50 images the opening surface 13 of the box 12 to obtain an image including the opening surface 13. The image data captured by the camera 50 is transmitted to the control part 60 (see FIG. 4). The robot 40 performs an opening operation in which the tapes 17, 18 attached to the opening surface 13 of the box 12 are cut by the cutter unit 51 attached to the head 44.

[0035] As shown in FIG. 1 and FIG. 2, a cylindrical vibrator 52 constituting a cutter unit 51 is attached to the support 49. A cutter 53 is fixed to the tip of the output shaft of the vibrator 52. The vibrator 52 and the cutter 53 are held in a predetermined position in which their axes are parallel to the optical axis direction of the camera 50, for example. The cutter unit 51 vibrates the cutter 53 with ultrasonic waves generated by the vibrator 52, and the cutter 53 in the vibrating state cuts the tapes 17, 18. The vibrator 52 is electrically connected to an oscillator (not shown) via a power line (not shown) passing through the inside or outside of the arm 43 along the arm 43, and ultrasonically vibrates with a periodically changing voltage supplied from the oscillator. The cutter 53 is moved relative to the box 12 by being positionally and attitude-controlled by the movement of the arm 43 of the robot 40, and cuts the tapes 17, 18 attached to the opening surface 13. That is, The robot 40 controls the posture of the arm 43 of the robot 40 to move the cutter 53 in the X direction along the opening surface 13, thereby cutting the first tape 17 attached to the opening surface 13. The robot 40 also controls the arm 43 to a posture in which the cutter 53 shown by the two-dot chain line in FIG. 2 is tilted at, for example, about 45 degrees, and moves the cutter 53 in the Y direction along the side edge of the opening surface 13, thereby cutting the second tape 18 attached to the side edge of the opening surface 13. The box 12 that the robot 40 cuts the tapes 17 and 18 to open is carried out by the conveyor 21. The carried-out box 12 is sent to an unpacking device (not shown) that is arranged downstream of the opening system 10 in the conveying direction X1. The unpacking device pushes outward a plurality of flaps of the box 12 after the tapes 17 and 18 have been cut, to make the box 12 in a state in which the contents can be removed, and further performs the work of removing the contents from the box 12.

[0036] Next, with reference to Fig. 3, the positioning of the box 12 to the work position SP where the box 12 is opened and the tapes 17, 18 attached to the opening surface 13 will be described. As shown in Fig. 3, the box 12 is, for example, a cardboard box, and is closed by a so-called "H-attaching" method using a first tape 17 attached along the center line of the opening surface 13 and a second tape 18 attached across the opening surface and side surfaces at two side edges of the opening surface 13 in a state where it intersects with the first tape 17. The tapes 17, 18 are, for example, adhesive tapes.

[0037] Here, the box 12 to be opened will be described with reference to FIG. 3. FIG. 3 shows the box 12 before opening, which is positioned at the work position SP on the conveyor 21. In the example shown in FIG. 3, the box 12 is positioned in the conveying direction X1 by being restricted in movement by a stopper 26 in the conveying direction X1, and is positioned in the width direction Y by a pair of guide members 28 sandwiching the box 12 from both side surfaces 12A. The box 12 has a box body 15 and four flaps 16 (only the outer two are shown in FIG. 3) folded in a state to close the upper opening 12K of the box body 15. Tapes 17 and 18 are attached along the periphery of the pair of flaps 16 on the upper side. A first tape 17 (center tape) is attached so as to extend in the X direction along the boundary between the pair of flaps 16 facing each other. The first tape 17 is attached along a center line that passes through the width center of the opening surface 13 of the box 12 and extends in the X direction. Further, a second tape 18 (side edge tape) is attached to the box 12 so as to extend in the Y direction along the boundary between both side edges of the pair of flaps 16 and the side surface 12B of the box 12. The opening device 11 cuts the first tape 17 attached to the boundary between the two flaps 16 on the opening surface 13 of the box 12, and the second tape 18 attached to the side edge of the opening surface 13 along the boundary between the two flaps 16 and the side surface 12B of the box 12.

[0038] As shown in Fig. 3, the first tape 17 attached to the opening surface 13 of the box 12 is cut along a first cutting path L1 shown by a dashed line in the figure. The second tape 18 attached to the side edge of the opening surface 13 of the box 12 is cut along a second cutting path L2 shown by a dashed line in Fig. 3. The first cutting path L1 is not the width center of the first tape 17 but a position corresponding to the boundary line of the pair of flaps 16. The second cutting path L2 is not the width center of the second tape 18 but a position corresponding to the boundary between the side edges of the pair of flaps 16 and the side surface 12B.

[0039] For example, a depalletizer is disposed upstream of the unpacking system 10, which performs unpacking work by taking out boxes 12 one by one from a group of boxes stacked on a pallet and placing them on the conveyor 21. The depalletizer reads the two-dimensional code marked on the box 12 with a reader to obtain box identification information. A control unit 60 shown in FIG. 4 possessed by the unpacking system 10 receives the box identification information from the depalletizer and obtains the box identification information in advance. The control unit 60 controls the drive of the cylinder 27 according to the size of the box 12 obtained based on the box identification information, and controls the position of the pair of guide members 28. Boxes 12 of various sizes are carried onto the conveyor 21 shown in FIG. 1 and FIG. 2, and the protrusion amount of the cylinder 27 is controlled according to the box identification information, so that any size of box 12 can be positioned in the width direction Y.

[0040] Next, the electrical configuration of the opening system 10 will be described with reference to Fig. 4. An operation panel 70 is electrically connected to the control unit 60 of the opening system 10. The operation panel 70 includes a display unit 71. The operation panel 70 is used when an operator performs operations to input various setting data and to give instructions to the opening system 10, such as starting and stopping operation. The control unit 60 causes the display unit 71 of the operation panel 70 to display a setting screen, a notification screen for notifying the operator of an error, etc.

[0041] The control unit 60 is electrically connected to the conveyor 21, the positioning device 22, and the sensor 29 that constitute the transport device 20. The control unit 60 is also electrically connected to the robot 40, the camera 50, and the cutter unit 51 that constitute the opening device 11. The control unit 60 controls the positioning device 22 based on the detection signal of the sensor 29 to position the box 12 carried in by the conveyor 21 at the work position SP. The control unit 60 also controls the height detection device 30 to detect the height position of the tapes 17, 18 on the opening surface 13 by the sensor unit 32. The control unit 60 controls the robot 40 to move the camera 50 to the imaging position. The control unit 60 acquires the image captured by the camera 50. The control unit 60 also controls the cutter unit 51 to ultrasonically vibrate the cutter 53.

[0042] The control unit 60 also includes an image processing unit 61, a calculation unit 62, and a memory 63. The memory 63 stores a program PR for cutting control, which is shown in the flow chart of FIG. 8. The control unit 60 includes a built-in computer such as a microprocessor. The image processing unit 61 and the calculation unit 62 are configured as software that is configured by the computer executing the program PR stored in the memory 63. The image processing unit 61 and the calculation unit 62 may be configured as hardware using electronic circuits in the control unit 60. The control unit 60 may also be configured as a separate unit including a robot controller that controls the robot 40 and a controller for an opening control system that controls the camera 50 and the cutter unit 51.

[0043] The control unit 60 calculates the cutting path of the tapes 17, 18 based on the height position of the tapes 17, 18 attached to the opening surface 13 of the box 12 detected by the height detection device 30 and the image CI (see FIG. 5) of the opening surface 13 captured by the camera 50 from the imaging position. The image processing unit 61 acquires the image CI including the opening surface 13g shown in FIG. 5 captured by the camera 50 of the opening surface 13, and performs a predetermined image processing on the image CI to acquire the outline of the opening surface 13 as shown in FIG. 5. The calculation unit 62 performs geometric calculations from the coordinates of a plurality of points on the outline of the opening surface 13 to obtain the first cutting path L1 and the second cutting path L2 for the robot 40 to control the position of the cutter 53 by controlling the arm 43. The control unit 60 controls the robot 40 to control the position of the cutter 53 along the first cutting path L1 and the second cutting path L2.

[0044] Next, the operation of the opening system 10 will be described. An operator operates the operation panel 70 to give an instruction to start operation. When the control unit 60 receives the instruction to start operation, it starts operation of the opening system 10. The control unit 60 reads out the program PR shown in the flowchart of FIG. 8 from the memory 63 and executes it.

[0045] The control unit 60 receives box identification information related to the box 12 carried onto the conveyor 21 from a palletizer performing a box de-stacking operation on the upstream side of the opening system 10. The box identification information includes information such as the product number, shape, and size of the box 12. When a sensor (not shown) detects that the box 12 has been carried onto the conveyor 21, the control unit 60 drives the cylinder 25 to move the stopper 26 from the retracted position to the regulating position shown in Figs. 1 to 3. When the box 12 is positioned in the conveying direction X1 and the sensor 29 detects the box 12, the control unit 60 drives the pair of cylinders 27 to sandwich the box 12 between the pair of guide members 28 and position it in the width direction Y. In this way, the box 12 is positioned at the work position SP.

[0046] The following describes the opening control that the control unit 60 executes the program PR shown in the flow chart of FIG. 8 and causes the opening device 11 to perform. First, in step S11, the control unit 60 detects the positions of the tapes 17 and 18 in the intersecting direction. That is, the control unit 60 detects the positions (height positions) of the tapes 17 and 18 attached to the opening surface 13 in the height direction Z, which is the intersecting direction intersecting with the opening surface 13 of the box 12. In detail, the control unit 60 controls the height detection device 30 to lower the sensor unit 32 from the detection start position to detect the height position of the opening surface 13. The height position of the opening surface 13 detected at this time corresponds to the position of the first tape 17 attached along the boundary between the two flaps 16 on the opening surface. Note that in this embodiment, the process of step S11 corresponds to an example of a "position detection step" that detects the positions of the tapes 17 and 18 in the intersecting direction intersecting with the opening surface 13 of the box 12 to which the tapes 17 and 18 are attached.

[0047] In step S12, the control unit 60 moves the camera 50 to an imaging position. That is, the control unit 60 controls the arm 43 of the robot 40 to place the camera 50 at an imaging position shown in Figs. 1 and 2 at a predetermined height above the opening surface 13. This imaging position of the camera 50 is a position above the opening surface 13 of the box 12 in the height direction Z by a distance equivalent to the focal length of the camera 50. When the camera 50 images a downward direction from this imaging position, the opening surface 13 is in focus.

[0048] In step S13, the control unit 60 causes the camera 50 to capture an image of the opening surface 13 of the box 12. More specifically, the control unit 60 outputs an imaging command signal to the camera 50. When the imaging command signal is input, the camera 50 performs an imaging operation. As a result, the camera 50 captures an image of the opening surface 13 of the box 12. Image data CI (hereinafter also simply referred to as "image CI") captured by the camera 50 of the opening surface 13 is sent to the control unit 60. Note that in this embodiment, the processing of step S13 corresponds to an example of an "imaging step" of capturing an image of the opening surface 13 of the box 12 to which the tapes 17, 18 are attached.

[0049] In this embodiment, the camera 50 of the robot 40 and the sensor unit 32 of the height detection device 30 are driven by independent moving systems. In steps S11 and S12, the robot 40 and the height detection device 30 are driven separately based on separate instructions from the control unit 60. For this reason, the detection of the position of the tapes 17, 18 in the intersecting direction by the sensor unit 32, that is, the detection of the height position of the tapes 17, 18 in this example where the intersecting direction is the height direction Z, and the imaging of the opening surface 13 from the imaging position by the camera 50 are performed in parallel.

[0050] In step S14, the control unit 60 performs image processing on the image CI including the opening surface 13g. The control unit 60 performs image processing, such as binarization processing, on the image CI including the opening surface 13g to generate an image that makes it easy to grasp the outline of the opening surface 13g. Note that if the outline of the opening surface of the box can be grasped, image processing may be omitted.

[0051] In step S15, the control unit 60 calculates the tape cutting path. More specifically, the control unit 60 determines the cutting height for controlling the height of the cutter 53 from the height positions of the tapes 17 and 18 detected by the height detection device 30. The control unit 60 also determines the distance (also called the "imaging distance") from the camera 50 at the imaging position to the tape 17 on the opening surface 13 from the height positions of the tapes 17 and 18 detected by the height detection device 30. The control unit 60 determines the cutting path of the cutter 53 in the XY plane of the camera coordinate system of the opening surface 13 by geometric calculation from the outer shape of the opening surface 13g in the image CI based on the position of the image coordinate system of the outer shape of the opening surface 13g in the image CI that has been image-processed, the imaging distance, and the optical parameters of the camera 50. That is, the control unit 60 determines the tape cutting path in the camera coordinate system from the imaging distance when the camera 50 images the opening surface 13 and the position and size of the opening surface 13g included in the captured image CI. Furthermore, the control unit 60 performs coordinate conversion of the tape cutting path in the camera coordinate system into the control coordinate system for robot control.

[0052] Here, by using the outline of the opening surface 13g, the first cutting path L1, which is the cutting path of the first tape 17, is obtained not as the width center line of the first tape 17, but as the position of the boundary line of the pair of flaps 16 located on the upper side that closes the opening 12K of the box 12. Also, the second cutting path L2, which is the cutting path of the second tape 18, is obtained not as the width center line of the second tape 18, but as the position of each boundary line between the pair of flaps 16 and both side surfaces 12B facing each other in the X direction of the box 12. The calculation of the first cutting path L1 and the second cutting path L2 is performed by the calculation unit 62 of the control unit 60 as follows.

[0053] As shown in FIG. 5, the calculation unit 62 obtains the coordinates (x1, y1), (x2, y2), (x3, y3), (x4, y4) of the vertices A, B, C, and D from the outline of the opening surface 13g of the box 12g in the image CI after image processing. Next, the control unit 60 obtains the midpoint E ((x1+x2) / 2, (y1+y2) / 2) of one pair of vertices A and B facing each other in the width direction Y intersecting with the longitudinal direction of the first tape 17, and the midpoint F ((x3+x4) / 2, (y3+y4) / 2) of another pair of vertices C and D. The line segment EF connecting these midpoints E and F is obtained as the cutting path Ta1 on the xy plane. Then, the calculation unit 62 converts the cutting path Ta1 on the xy plane from the image coordinate system to the camera coordinate system, and further converts it to the control coordinate system of the robot control, to obtain the cutting path T1 on the XY plane of the control coordinate system. The coordinate of the cutting position (cutting height) in the Z direction uses the coordinate Hz of the height position of the tape 17 detected by the height detection device 30. Therefore, the first cutting path L1 is defined by the cutting path T1 (line segment EF in the control coordinate system) on the XY plane and the Z coordinate value Hz. The control unit 60 determines the first cutting path L1 from multiple position coordinates including two or more vertices in the outline of the opening surface 13g in the captured image CI. Any vertices may be used as the two or more vertices in the outline of the opening surface 13g as long as the first cutting path L1 can be obtained, and the calculation method can also be appropriately selected.

[0054] 5, the calculation unit 62 determines the line segment AB connecting the vertices A and B and the line segment CD connecting the vertices C and D as the cutting paths Ta2 on the xy plane of the two second tapes 18. The calculation unit 62 then converts the cutting path Ta2 on the xy plane from the image coordinate system to the camera coordinate system and further to the control coordinate system to determine the cutting path T2 on the XY plane of the control coordinate system. The coordinate Hz of the height position of the tape 17 detected by the height detection device 30 is used as the coordinate of the cutting position (cutting height) in the Z direction. Therefore, the second cutting path L2 is defined by the cutting path T2 on the XY plane (the line segments AB and CD in the control coordinate system) and the Z coordinate value Hz.

[0055] The second cutting path L2 can also be obtained by taking into consideration the curvature of the edge line EL of the side edge of the opening surface 13g as shown in FIG. 6. As shown in FIG. 6, a plurality of points are taken on the edge line EL between the vertices AB at a substantially constant pitch, and the calculation unit 62 converts the xy coordinates of these points from the image coordinate system to the camera coordinate system, and further to the control coordinate system of the robot control, and obtains the second cutting path L2 on the left side in FIG. 6 using the XY coordinates of the points in the control coordinate system obtained and the Z coordinate value Hz. The calculation unit 62 also converts the xy coordinates of the points on the edge line EL between the vertices CD in FIG. 6 from the image coordinate system to the camera coordinate system, and further to the control coordinate system, and obtains the second cutting path L2 on the right side in FIG. 6 using the XY coordinates of the points in the control coordinate system obtained and the Z coordinate value Hz. The calculation method for obtaining each cutting path L1, L2 using the coordinates of the outer shape of the opening surface 13g in the image coordinate system can be changed as appropriate.

[0056] In step S16, the control unit 60 controls the robot 40 to position the cutter 53 along the cutting paths L1 and L2 of the tapes 17 and 18, and cuts the tapes 17 and 18. That is, the control unit 60 controls the robot 40 to position the cutter 53 of the cutter unit 51 fixed to the head 44 at the tip of the arm 43 along the cutting paths L1 and L2 calculated in step S15, and cuts the tapes 17 and 18. In detail, the control unit 60 moves the cutter 53 to the start point of the first cutting path L1, and controls the angle of the cutter 53 to the first attitude angle when cutting the first tape 17, and moves the cutter 53 to the end point while controlling the position along the first cutting path L1, and cuts the first tape 17. Therefore, the cutter 53 moves along the cutting path L1 in FIG. 3, and cuts the first tape 17 along the boundary between the pair of flaps 16.

[0057] Furthermore, when cutting the second tape 18, the control unit 60 moves the cutter 53 to the starting point of the second cutting path L2, controls the angle of the cutter 53 to a second attitude angle shown by the two-dot chain line in Fig. 2 when cutting the second tape 18, and moves the cutter 53 to the end point while controlling the position along the second cutting path L2, thereby cutting the second tape 18. The second tape 18 is cut by the movement of the cutter 53 along the cutting path L2 in Fig. 3.

[0058] In addition, when the second cutting path L2 is obtained by the point cloud on the edge line EL shown in FIG. 6, the cutter 53 is positionally controlled as shown in FIG. 7. As shown in FIG. 7, the cutter 53 first moves along the first cutting path L1 as shown by the dashed arrow (1) in the figure, and cuts the first tape 17. Next, the cutter 53 moves along the curved second cutting path L2 as shown by the dashed arrow (2) in FIG. 7, and cuts one of the second tapes 18. Furthermore, the cutter 53 moves along the curved second cutting path L2 as shown by the dashed arrow (3) in FIG. 7, and cuts the other of the second tapes 18. As shown in FIG. 7, even if the side surface 12B of the box 12 is curved, the second tape 18 is cut by the cutter 53 moving along the curve of the edge line EL of the opening surface 13. In this embodiment, the processing of step S16 corresponds to an example of a "control step" in which the position of the cutter 53 is controlled based on the cutting height based on the height position of the opening surface and the cutting path of the tape geometrically calculated from the outline of the opening surface 13g in the captured image CI to cut the tapes 17 and 18.

[0059] Therefore, the cutter 53 moves along the cutting path L1 shown in FIG. 3 while being inserted into the first tape 17 at a predetermined depth. Therefore, even if the opening surface 13 is somewhat deformed, the first tape 17 is reliably cut at the boundary between the pair of flaps 16. The cutter 53 penetrates slightly deeper than the thickness of the first tape 17 without penetrating excessively into the box 12. Therefore, the first tape 17 can be reliably cut by the cutter 53, and the cutter 53 can be prevented from damaging the contents inside the box 12. Also, as shown in FIG. 3, the two second tapes 18 attached to the two side edges of the box 12 are cut by the cutter 53 moving along the second cutting path L2.

[0060] As shown in FIG. 9(a), the height detection device 30 can be configured to be movable in the X direction as well as the height direction Z, which is a direction intersecting the opening surface 13. In the example of FIG. 9(a), the height detection device 30 has a running platform 36 at the bottom, and the running platform 36 moves in the X direction while being guided by a rail 37. The sensor unit 32 of the height detection device 30 emits detection light from the detection unit 33 toward the Y direction (the back side in the direction perpendicular to the paper surface in FIG. 9) from a position side facing the side surface 12B of the box 12. The height detection device 30 can be raised and lowered in the height direction Z by driving the motor 35 while emitting detection light in the Y direction from the detection unit 33, and can also be moved in the X direction by driving the motor 38 arranged on the running platform 36. As shown in FIG. 9(b), when the sensor unit 32 detects the height position P of the first tape 17 by moving in the height direction Z while emitting detection light from the detection unit 33, it can detect a height position Q higher than the height position P of the first tape 17 by moving in the X direction while emitting detection light and also moving in the height direction Z. As shown in FIG. 9(b), when the pair of flaps 16 is floating, the height position of the first tape 17 detected by the sensor unit 32 changes with a slight difference in position in the X direction. In addition, since the first tape 17 is very thin, a slight deviation in the height of the cutter 53 causes a cutting error in the first tape 17. However, in the height detection device 30 shown in FIG. 9(a), the sensor unit 32 can scan in the X direction, which is the width direction of the first tape 17, in addition to the height direction Z (cross direction) while emitting detection light in the Y direction, so that the highest position suitable as a cutting position in the height direction Z of the first tape 17 can be detected more accurately. Therefore, even if the flap 16 is lifted and tilted as shown in FIG. 9(b), the height position of the cutting path of the first tape 17 can be properly detected and the first tape 17 can be cut reliably without cutting errors.

[0061] As described above in detail, according to the first embodiment, the following effects can be obtained. (1) The opening device 11 for the box 12 is provided for cutting the affixed tapes 17, 18 to open the box 12. The opening device 11 is provided with a height detection device 30 for detecting the positions of the tapes 17, 18 in a height direction Z intersecting with the opening surface 13 of the box 12 to which the tapes 17, 18 are affixed, and a camera 50 for capturing an image CI including the opening surface 13g by capturing an image of the opening surface 13 from the height direction Z. The opening device 11 is also provided with a cutter 53 for moving relative to the box 12 to cut the tapes 17, 18. The opening device 11 is further provided with a control unit 60 for controlling the position of the cutter 53 along cutting paths L1, L2 of the tapes 17, 18 that are determined based on the positions of the tapes 17, 18 in the height direction Z detected by the height detection device 30 and the position of the outline of the opening surface 13g in the captured image CI to cut the tapes 17, 18. Therefore, since the cutting paths L1, L2 are determined based on the positions of the tapes 17, 18 in the height direction Z intersecting with the opening surface 13 and the position of the outline of the opening surface 13g in the captured image CI of the opening surface 13, the position of the cutter 53 can be appropriately controlled with respect to the tapes 17, 18 even if the positions of the tapes 17, 18 vary slightly in the height direction Z. Therefore, defective opening of the box 12 caused by incorrect cutting of the tapes 17, 18 attached to the opening surface 13 of the box 12 can be reduced.

[0062] (2) The height detection device 30 has a sensor unit 32 that can move in the height direction Z while emitting detection light in a direction parallel to the opening surface 13 with respect to the box 12, and a lifting mechanism 31 that moves the sensor unit 32 in the height direction Z. The sensor unit 32 is moved in the height direction Z to detect the position of the tapes 17, 18 in the height direction Z. The lifting mechanism 31 as an example of a first moving mechanism and the robot 40 as an example of a second moving mechanism that moves the camera 50 to an imaging position are provided separately. Therefore, the position detection of the tapes 17, 18 in the height direction Z and the imaging of the opening surface 13 can be performed in parallel by independent moving mechanisms. Compared to a configuration in which the height detection device 30 and the camera 50 are position-controlled by the same moving mechanism, the cutting paths L1, L2 of the cutter 53 can be determined quickly, and the cutting work of the tapes 17, 18 can be realized at high speed.

[0063] (3) The first tape 17 attached to the boundary between the two flaps 16 on the opening surface 13 of the box 12 and the second tape 18 attached along the boundary between the two flaps 16 and the side surface 12B of the box 12 are to be cut. The control unit 60 determines a first cutting path L1 of the first tape 17 from a plurality of position coordinates including two or more vertices in the outline of the opening surface 13g in the captured image CI, and controls the position of the cutter 53 along the determined first cutting path L1 to cut the first tape 17. The control unit 60 also determines an edge line EL that intersects with the side surface 12B, which is the adjacent surface on the opening surface 13, from the outer periphery of the opening surface 13g in the captured image CI by the camera 50, and controls the position of the cutter 53 to cut the second tape 18 along a second cutting path L2 along the determined edge line EL. Therefore, the cutter 53 is positionally controlled along the second cutting path L2 along the edge line where the opening surface 13 and the side surface 12B of the box 12 intersect, so that even if the side surface 12B of the box 12 is deformed, the second tape 18 can be cut along the curved edge line caused by the deformation.

[0064] (4) The method for opening the box 12 cuts the tapes 17, 18 attached along the periphery of the flap 16 that closes the opening 12K of the box 12 to open the box 12. The method includes a position detection step (S11) for detecting the positions of the tapes 17, 18 in the height direction Z intersecting with the opening surface 13 of the box 12 to which the tapes 17, 18 are attached, and an imaging step (S12, S13) for imaging the opening surface 13 of the box 12 to obtain an image CI. The method also includes a control step (S15, S16) for cutting the tapes 17, 18 by controlling the position of the cutter 53 along the cutting paths L1, L2 of the tapes 17, 18 that are determined based on the positions of the tapes 17, 18 in the height direction Z detected by the position detection step and the position of the outline of the opening surface 13g in the image CI obtained by the imaging step. Thus, similar to the opening device 11, the failure to open the box 12 due to cutting errors of the tapes 17, 18 can be reduced.

[0065] (5) Incidentally, if the tape 17 can be recognized from the captured image CI, a method of cutting along the width center line of the first tape 17 is also conceivable. However, if the width center of the first tape 17 is shifted in the width direction from the boundary line between the two flaps 16, the flap 16 will be cut and the box 12 will not be opened. In this embodiment, the first cutting path L1 is determined from the outline of the opening surface 13g in the captured image CI, so that the first tape 17 can be cut along the boundary line between the pair of flaps 16. Therefore, the first tape 17 can be cut along the boundary line of the flaps 16, and mistakes in opening the box 12 can be further reduced.

[0066] Second embodiment Next, a second embodiment will be described with reference to Figures 1, 10 and 11. In this embodiment, the height detection device 30 is not provided.

[0067] As shown in FIG. 1, the head 44 attached to the tip of the arm 43 of the robot 40 is provided with a camera 50, a cutter unit 51, and a distance sensor 55 shown by a two-dot chain line in FIG. 1 as an example of a height position detection unit. The distance sensor 55 measures the distance to the opening surface 13 in order to obtain the height position of the opening surface 13, instead of the height detection device 30 in the first embodiment. As shown in FIG. 10, the distance sensor 55 is attached to the support part 49 of the head 44 so that the angle can be changed. When the cutter 53 is in the cutting posture, it faces the opening surface 13 of the box 12, and it is possible to measure the distance LZ to the opening surface 13. For example, the distance sensor 55 is provided so that it can be arranged at a position in the direction of travel of the cutter 53 when cutting the tapes 17 and 18 on the support part 49. During the movement of the cutter 53 to cut the tapes 17 and 18, the distance LZ is measured at a position on the opening surface 13 where the cutter 53 reaches and cuts after a predetermined time has elapsed. When the head 44 is inclined to the position when the cutter 53 cuts the tapes 17, 18, the distance sensor 55 is disposed in a position where the direction of its detection light HL is the height direction Z and faces the opening surface 13.

[0068] 1, when the camera 50 captures an image of the opening surface 13 from the imaging position, the distance sensor 55 measures the distance to the opening surface 13 and detects the height position Hz of the opening surface 13 from the measured distance. That is, the distance sensor 55 detects the height position Hz of the opening surface 13 of the box 12 in place of the height detection device 30 in the first embodiment.

[0069] In addition, the control unit 60 controls the position of the cutter 53 in the height direction Z in response to a change in the distance LZ to the opening surface 13 detected by the distance sensor 55. The memory 63 of the control unit 60 stores a program PR shown in the flowchart of Fig. 11. The computer in the control unit 60 executes the program PR shown in Fig. 11 to control the cutting of the opening device 11. The cutting control of the opening device 11 performed by the control unit 60 executing the program PR shown in Fig. 11 will be described below.

[0070] First, in step S21, the control unit 60 moves the camera 50 to an imaging position. That is, the control unit 60 controls the robot 40 to move the camera 50 to an imaging position that is a position above the opening surface 13. The imaging position may be a fixed position, or, for example, the height of the box 12 may be acquired from the box identification information, and a position that is above the height position of the opening surface 13 of the box 12 by the focal length of the camera 50 may be set as the imaging position, and the camera 50 may be moved to this imaging position. Also, based on the distance to the opening surface 13 measured by the distance sensor 55, a moving distance to a position where the distance from the camera 50 to the opening surface 13 is the focal length may be calculated, and the camera 50 may be moved by this moving distance to be placed at the imaging position.

[0071] In step S22, the control unit 60 causes the camera 50 to capture an image of the opening surface 13 of the box 12. Image data CI of the opening surface 13 captured by the camera 50 is sent to the control unit 60. Note that in this embodiment, the process of step S22 corresponds to an example of an "imaging step" of capturing an image of the opening surface 13 of the box 12 to obtain the captured image CI.

[0072] In step S23, the control unit 60 uses the distance sensor 55 to measure the distance to the tapes 17, 18 attached to the opening surface 13 of the box 12. As shown in Fig. 1, when the camera 50 is in an imaging position for imaging the opening surface 13, the distance sensor 55 measures the distance Hs to the tapes 17, 18 attached to the opening surface 13. Since the heightwise distance ΔH between the camera 50 and the distance sensor 55 is known, the distance Ha (=Hs-ΔH) from the camera 50 to the opening surface 13 to which the tapes 17, 18 are attached can be calculated. In the example of Fig. 1, the opening surface 13 is the top surface of the box 12, so the imaging position of the camera 50 is directly above the opening surface 13. In contrast, for example, if the opening surface 13 is oriented horizontally, the control unit 60 controls the robot 40 to orient the head 44 horizontally facing the opening surface 13, capture an image of the horizontal opening surface 13 from directly beside it with the camera 50, and have the distance sensor 55 measure the distance to the opening surface 13.

[0073] In step S24, the control unit 60 performs image processing on the image CI including the opening surface 13g. The control unit 60 performs, for example, binarization processing on the image CI including the opening surface 13g to obtain an image CI that makes it easy to grasp the outline of the opening surface 13g.

[0074] In step S25, the control unit 60 calculates the cutting paths of the tapes 17 and 18. In detail, the control unit 60 uses the distance Hs measured by the distance sensor 55 to calculate the distance Ha from the camera 50 to the tapes 17 and 18 attached to the opening surface 13 of the box 12, and as described in Figures 5 and 6, calculates the first cutting path L1 shown in Figure 5 and the second cutting path L2 shown in Figure 5 or 6 by geometric calculation from the outline of the opening surface 13g after image processing.

[0075] In step S26, the control unit 60 cuts the tapes 17 and 18 while controlling the height of the cutter 53 in accordance with the distance detected by the distance sensor 55. As shown in FIG. 10, the control unit 60 cuts the first tape 17 by moving the cutter 53 along the first cutting path L1 while controlling its position under the control of the robot 40, and during this movement process, the distance sensor 55 measures the distance LZ to the first tape 17 in the height direction Z (crossing direction) at the position of the cutter 53's travel direction. The control unit 60 controls the position of the cutter 53 in the height direction (crossing direction) according to the change in the distance LZ to the first tape 17 measured by the distance sensor 55 at the position of the cutter 53's travel direction. As a result, as shown in FIG. 10, even if the opening surface 13 of the box 12 is curved, such as concave, the cutter 53 is height-controlled to follow the surface shape of the curved first tape 17, so that the first tape 17 attached to the curved opening surface 13 can also be appropriately cut. Similarly, the cutter 53 cuts the second tape 18 while controlling its height according to the detection distance of the distance sensor 55. Even if opening surface 13 of box 12 is curved, such as concave, cutter 53 can cut second tape 18 by following the surface shape of the curved second tape 18. Furthermore, even if side surface 12B of box 12 is deformed and edge line EL of the side edge of opening surface 13 is curved, cutter 53 can be positionally controlled to follow the curved edge line EL to reliably cut second tape 18, and cutter 53 can be prevented from damaging the contents inside box 12.

[0076] As described above in detail, according to the second embodiment, the following effects can be obtained. (6) The position detection unit is a distance sensor 55 that measures the distance to the tapes 17, 18 in the height direction Z and detects the position of the tapes 17, 18 in the height direction Z. The control unit 60 causes the distance sensor 55 to detect the distance to the surface to which the tapes 17, 18 are attached, and controls the position of the cutter 53 in the height direction Z in accordance with changes in the distance to the tapes 17, 18. Thus, the tapes 17, 18 can be cut following the depressions in the opening surface 13 of the box 12.

[0077] (7) The method for opening the box 12 cuts the tapes 17, 18 attached along the periphery of the flap 16 that closes the opening 12K of the box 12 to open the box 12. The method includes a position detection step (S23) for detecting the positions of the tapes 17, 18 in the height direction Z intersecting with the opening surface 13 of the box 12 to which the tapes 17, 18 are attached, and an imaging step (S21, S22) for imaging the opening surface 13 of the box 12. The method also includes a control step (S25, S26) for cutting the tapes 17, 18 by controlling the position of the cutter 53 along the cutting paths L1, L2 of the tapes 17, 18 that are determined from the positions of the tapes 17, 18 in the height direction Z detected by the position detection step and the outer shape of the opening surface 13 in the captured image CI acquired in the imaging step. Thus, similar to the opening device 11, defective opening of the box 12 caused by incorrect cutting of the tapes 17, 18 can be reduced.

[0078] Third embodiment Next, a third embodiment will be described with reference to Figures 12 to 20. In this embodiment, similarly to the second embodiment, the robot 40 is provided with a distance sensor 55 as an example of a position detection unit, and the camera 50 as an example of an imaging unit is fixed at a predetermined height and captures an image of the opening surface 13 of the box 12 located below.

[0079] 12 and 13, the opening device 11 for opening a box 12 includes an articulated robot 40, similar to the first and second embodiments. The robot 40 has arm portions 43A, 43C, and 43D that constitute an arm 43, similar to the first embodiment. The robot has a 6-axis or 7-axis head 44 that is detachably attached to the arm portion 43D. The head 44 is supported by a rotating portion 48 that is rotatable about an axis using a motor (not shown) as a power source at the tip of the arm 43.

[0080] The box opening system 10 shown in FIG. 12 includes an input conveyor 81 for inputting the box 12 to the opening device 11, and an output conveyor 82 for outputting the opened box 12 from the opening device 11. The opening device 11 of this embodiment includes an elevation type conveyor 83 as an example of a transport mechanism. The elevation type conveyor 83 is disposed between the input conveyor 81 and the output conveyor 82. The input conveyor 81 and the output conveyor 82 are disposed at the same height, and are, for example, roller conveyors each having a plurality of rollers 81A and 82A. The opening device 11 receives the unopened box 12 that has been input from the input conveyor 81 onto the conveyor 83, and delivers the opened box 12 that has been opened by the robot 40 to the output conveyor 82.

[0081] As shown in Fig. 12 and Fig. 13, the conveyor 83 is, for example, a belt conveyor. The conveyor 83 includes a pair of rollers 84, a support base 83A that supports the rollers 84, a conveyor belt 85 wound around the pair of rollers 84, and a motor 83M that drives one of the rollers 84. The opening device 11 includes a control unit 60 (see Fig. 4) that is substantially the same as that of the first embodiment. When the control unit 60 drives the motor 83M in the forward direction, the conveyor 83 is driven in a direction to convey the box 12 in the first direction X1, and when the control unit 60 drives the motor 83M in the reverse direction, the conveyor 83 is driven in a direction to convey the box 12 in the second direction X2 that is the opposite direction to the first direction X1.

[0082] In this embodiment, the conveyor 83 is stopped at the work position by stopping the conveyor 83. A plurality of first sensors 29 are arranged on both sides of the conveyor belt 85 in the width direction of the conveyor 83 to detect the box 12 that has reached the work position SP on the conveyor belt 85. The plurality of first sensors 29 detect boxes 12 of different sizes, and can stop any size of box 12 at a predetermined work position on the conveyor belt 85. In this embodiment, the robot 40 may convey the box 12 in the second direction X2 during the process of cutting the tapes 17 and 18. In this case, the conveyor 83 is provided with a second sensor 72 capable of detecting the box 12 in order to stop the box 12 conveyed in the second direction X2 at a predetermined stop position. The first sensor 29 and the second sensor 72 are, for example, optical sensors. The optical sensor includes a light emitter and a light receiver, and detects the box 12 when the box 12 blocks light from the light emitter to the light receiver. The first sensor 29 and the second sensor 72 may be non-contact sensors other than optical sensors, or may be contact sensors.

[0083] An assembly 110 surrounding the lifting mechanism 86 and the robot 40 includes a plurality of pillars 111 and a beam 112 horizontally disposed between the upper ends of the pillars 111. A camera 50 as an example of an imaging unit is fixed to one beam 112 extending in the conveying direction X at a position directly above and a predetermined distance above the center of the upper surface of the conveyor belt 85. The camera 50 images the opening surface 13 of the box 12 placed at the work position SP on the conveyor 83 from a height position a predetermined distance away in the intersecting direction.

[0084] Moreover, an assembly 120 that supports the robot 40 is disposed inside the assembly 110. The assembly 120 includes a plurality of pillars 121, a plurality of beams 122 horizontally disposed between the pillars 121, and a support plate 123 horizontally disposed at a predetermined height position between the pillars 121. The robot 40 is installed on the support plate 123.

[0085] The lifting conveyor 83 is in a standby position H0 (lowered position) shown by a two-dot chain line in Fig. 12 when carrying in and out the box 12, and when the robot 40 performs the work of opening the box 12, it rises from the standby position H0 to a working height position H1 shown by a solid line in Fig. 12 in accordance with the height dimension of the box 12. Fig. 12 shows the working height position H1 of the conveyor 83 when the box 12 is at its maximum size. The robot 40 performs the opening work by cutting the tapes 17, 18 attached to the opening surface 13 of the box 12 with a cutter unit 51 attached to the head 44.

[0086] 12 and 13, the opening device 11 includes a lifting mechanism 86 that lifts and lowers the boxes 12 together with the conveyor 83. The lifting mechanism 86 includes the conveyor 83 and a lifting unit 87. The lifting unit 87 includes a pair of guide rods 88, a pair of lifting sliders 89 movable along the pair of guide rods 88, and a support table 90 fixed to the pair of sliders 89. The conveyor 83 is supported on the support table 90 via a plurality of support rods 91.

[0087] 12 and 13, the lifting unit 87 includes a lifting motor 92 serving as a drive source thereof, and a power transmission mechanism 93 for converting the rotational power of the motor 92 into a linear motion in the vertical direction Z for lifting and lowering the conveyor 83. The power transmission mechanism 93 is, for example, a belt-type power transmission mechanism. The power transmission mechanism 93 includes a pulley 94 fitted to the output shaft of the motor 92, a drive belt 97 wound between a pulley 96 fitted to a rotating shaft 95, a pulley 98 fitted to the rotating shaft 95 common to the pulley 96, and a timing belt 100 wound between a pulley 99 located above the pulley 98 and a predetermined distance away in the vertical direction Z. The rotating shaft 95 is supported rotatably in a horizontal state at a lower position near the bottom plate on which the guide rod 88 is erected. Two pairs of upper and lower pulleys 98, 99 are provided, and two timing belts 100 are wound around the two pairs of pulleys 98, 99 and extend vertically at a predetermined interval in the conveying direction X. The motor 92 is, for example, a servo motor.

[0088] A portion of the two timing belts 100 is fixed to the support table 90. When the control unit 60 drives the motor 92 in the forward direction, the conveyor 83 rises, and when the control unit 60 drives the motor 92 in the reverse direction, the conveyor 83 descends. A flexible cable 101 that guides power lines and signal lines that supply power to the motor 83M and sensors 29, 72, etc., provided on the conveyor 83 is provided so as to hang down from the support table 90. Note that the power transmission mechanism 93 is not limited to a belt-type power transmission mechanism and may be of another type.

[0089] The lifting mechanism 86 adjusts the height of the box 12 by raising and lowering the conveyor 83, thereby positioning the opening surface 13 of the box 12 at the focal position of the camera 50. In other words, the lifting mechanism 86 can position the opening surface 13 at the focal position regardless of the size of the box 12 by controlling the motor 92. The lifting mechanism 86 is equipped with a height sensor (not shown) that detects that the opening surface 13 of the box 12 has reached the working height position H1, which is the focal position of the camera 50. When the height sensor detects the opening surface 13 of the box 12, the control unit 60 stops driving the motor 92. Note that the control unit 60 may obtain the height dimension of the box 12 from the box identification information received from the upstream control system, and control the motor 92 by the drive amount according to the height dimension to control the conveyor 83 to rise until the opening surface 13 reaches the focal position of the camera 50.

[0090] 13, the dashed dotted line indicates the working range WS of the robot 40. The working range WS of the robot 40 is the working range of point P when the center of rotation of the bending axis of the wrist of the arm 43 of the robot 40 is set to point P. If the cutting path (cutting line) of the box 12 to be worked on is within the working range WS, cutting of the tapes 17, 18 along the cutting path is guaranteed regardless of the posture of the robot 40 at the time of cutting.

[0091] As shown in FIG. 13, the width of the motion range WS in the width direction Y when viewed from the conveying direction X is narrower at the upper and lower positions of the motion range WS and is wider at the height between them, forming an arc-shaped line. The motion range WS is widest in the width direction Y at a height near the base end of the arm portion 43A, which corresponds to the upper arm of the arm 43. The motion range WS becomes narrower in the width direction Y as it moves downward from the height near the base end of the arm portion 43A, and falls outside the motion range WS at a position below a predetermined position that is a predetermined distance below the installation surface of the robot 40. If the conveyor 83 is positioned at the standby position H0 when performing the tape cutting operation, the opening surface 13 of the maximum size box 12 is located in a relatively wide area within the motion range WS. However, the opening surface 13 of the minimum size box 12 has a portion that falls outside the motion range WS. In other words, there is a risk that the tape 17, 18 of the minimum size box 12 cannot be cut.

[0092] Furthermore, when the robot 40 performs a tape cutting operation, the head 44 is in a position in which it is hanging down from the tip of the arm 43 or in a position inclined at a predetermined angle. Taking into consideration the length of the head 44 in the vertical direction Z when it is in this cutting position, the working height HF of the box 12 is set so that the tape cutting operation using the cutter 53 can be performed at a height position where the arm 43 has the widest operating range WS. The working height HF at which the opening surface 13 is located is set to a height at which the arm 43 has the widest operating range WS when the cutter 53 is at that height. In other words, the height of the opening surface 13 during the tape cutting operation is set to a height that is lower by the height dimension of the head 44 than the height at which the arm 43 has the widest operating range WS.

[0093] Here, the working height HF refers to the height position at which the opening surface 13 to which the tapes 17 and 18 are attached is located. The conveyor 83 is raised by the lifting mechanism 86 from the standby position H0 until the opening surface 13 of the box 12 reaches the working height HF. Therefore, the height of the conveyor 83 is adjusted by the lifting mechanism 86 so that the opening surface 13 is always located at the working height HF for boxes 12 of any size from the smallest size to the largest size.

[0094] The camera 50 is fixed at a height position where the opening surface 13 located at the working height HF of the box 12 is the focal point. In other words, the camera 50 is fixed at a height position where the focal length is the distance between the camera 50 and the opening surface 13 when the box 12 is at the working height HF. Therefore, the camera 50 captures a focused, clear image including the entire opening surface 13 when the box 12 is viewed from almost directly above.

[0095] The imaging position of the camera 50 is set at a predetermined height above the opening surface 13 in a direction (vertical direction Z) perpendicular to the opening surface 13 at the working height HF. The camera 50 acquires an image including the opening surface 13. The image data captured by the camera 50 is transmitted to the control unit 60 (see FIG. 4).

[0096] The opening device 11 includes a control unit 60 having the configuration shown in FIG. 4, similarly to the first embodiment. However, in the third embodiment, a liftable conveyor 83 is electrically connected to the control unit 60 instead of the conveyor 21 in FIG. 4, and a distance sensor 55 is electrically connected to the control unit 60 instead of the height detection device 30 to detect the height position of the opening surface 13. In addition, in the third embodiment, the positioning of the box 12 at the work position is performed by stopping control of the conveyor 83, so that a plurality of sensors 29 electrically connected to the control unit 60 are provided according to the types of sizes of the boxes 12. When one of the plurality of sensors 29 corresponding to the size of the box 12 determined from the box identification information detects the box 12 and turns on, the control unit 60 stops the conveyor 83, thereby stopping the box 12 at the work position SP on the conveyor 83. When the box 12 is at the work position SP, for example, the optical axis of the camera 50 coincides with the center of the opening surface 13.

[0097] The control unit 60 receives the box identification information from the depalletizer and acquires the box identification information in advance. Based on the size and height dimension information of the box 12 acquired based on the box identification information, the control unit 60 controls the lifting unit 87 to raise the conveyor 83 from the standby position H0 and raise the box 12 on the conveyor 83 to a position where the opening surface 13 reaches the working height HF. For this reason, the conveyor 83 for the maximum size box 12 is raised from the standby position H0 shown by the two-dot chain line in Fig. 12, and is disposed at a position where the opening surface 13 reaches the working height HF as shown in Figs. 12 and 13. For the minimum size box 12, the conveyor 83 is raised from the standby position H0 shown by the two-dot chain line in Fig. 14 to a working height position H2 according to the height dimension of the minimum size box 12, and is disposed at a position where the opening surface 13 of the box 12 reaches the working height HF as shown by the solid line in Fig. 14.

[0098] Next, the head 44 will be described with reference to FIGS. 15 and 16, the head 44 is detachably attached to the rotating part 48 of the robot 40, similarly to the first embodiment. The head 44 includes a support part 49, a cutter unit 51, a distance sensor 55, and rollers 56 as an example of a pair of rolling elements. The cutter unit 51, the distance sensor 55, and the pair of rollers 56 are each assembled to the support part 49. The support part 49 is configured so that a base end portion thereof, which is the end portion opposite the cutter 53 in the longitudinal direction, can be attached to the rotating part 48.

[0099] 15 and 16, cutter unit 51 has a configuration similar to that of the first embodiment, and includes a cylindrical vibrator 52 and a cutter 53 detachably fixed to the tip of the output shaft of vibrator 52. Cylindrical vibrator 52 is housed in a recess of support part 49 and fixed to bottom part 49A of support part 49 by fastening with a bolt (not shown) via connecting member 57. Power line 52A extending from the base end part of cutter unit 51 is electrically connected to an oscillator (not shown), and a periodically changing voltage supplied from the oscillator through power line 52A causes vibrator 52 to generate ultrasonic vibration in the output shaft, which causes cutter 53 fixed to the output shaft to ultrasonically vibrate.

[0100] 15 and 16, the distance sensor 55 is attached to the opposite surface of the bottom 49A of the support part 49 to which the cutter unit 51 is attached. The distance sensor 55 outputs an output wave OW such as an electromagnetic wave (including light) or a sound wave toward the tip direction where the cutter 53 is located, and detects the reflected wave as an electrical signal to measure the distance to the reflecting surface. Note that the detection method of the distance sensor 55 can be appropriately selected as long as it is capable of detecting the distance.

[0101] 15 and 16 are supported on the bottom of the support 49 in such a manner that the pair of rollers 56 are disposed on both sides of the cutter 53 in the moving direction when the cutter 53 cuts the tapes 17 and 18. The tip of the cutter 53 protrudes a predetermined amount toward the tip side from the common tangent line at the portion where the pair of rollers 56 contact when rolling on the box 12. This predetermined amount corresponds to the cutting depth when the cutter 53 cuts the tapes 17 and 18. When the robot 40 cuts the tapes 17 and 18, the pair of rollers 56 roll on the tapes 17 and 18, so that the cutting depth of the cutter 53 into the tapes 17 and 18 is almost constant, and the contents of the box 12 are not damaged. Even if the opening surface 13 of the box 12 is curved due to a dent or the like, the pair of rollers 56 roll along the curved surface, so that the cutting depth of the cutter 53 is almost constant. This avoids the occurrence of portions of the tapes 17, 18 that cannot be cut due to an insufficient cutting depth of the cutter 53.

[0102] Next, the operation of the box opening device 11 will be described. Boxes 12 of various height dimensions, from the smallest size to the largest size, are carried from the carry-in conveyor 81 to the conveyor 83 at the standby position H0. The control unit 60 acquires information on the size and height dimensions of the boxes 12 based on the box identification information acquired in advance. The conveyor 83 transports the boxes 12 received from the carry-in conveyor 81 in the first direction X1. When one of the first sensors 29 corresponding to the size of the box 12 being transported on the conveyor 83 detects the box 12, the control unit 60 stops driving the conveyor 83. As a result, the box 12 stops at the work position SP on the conveyor 83.

[0103] Thereafter, the control unit 60 controls the opening device 11 in accordance with the flowchart shown in FIG. 20, and performs opening control for cutting the tapes 17, 18 attached to the box 12 to open the box 12. First, in step S31, the control unit 60 moves the box 12 to the focal position of the camera 50. The control unit 60 drives the motor 92 in the forward direction to raise the conveyor 83. When the height sensor detects the box 12, the control unit 60 stops driving the motor 92. As a result, the opening surface 13 of the box 12 is located at the working height HF, which is located at the focal position of the camera 50.

[0104] The following steps S32 to S34 are similar to the processes in steps S13 to S15 in FIG. 8 in the first embodiment. In step S32, the control unit 60 causes the camera 50 to capture an image of the opening surface 13 of the box 12. The camera 50 acquires an image CI (see FIG. 5) including the opening surface 13g. The control unit 60 acquires the image CI captured by the camera 50. When the camera 50 captures the image, the robot 40 retreats the arm 43 to a standby position that does not interfere with the imaging of the box 12. The robot 40 waits, for example, with the arm 43 facing either upstream or downstream in the conveying direction X relative to the front.

[0105] In step S33, the control unit 60 performs image processing on the image including the opening surface 13g. The control unit 60 performs image processing, such as binarization processing, on the image CI including the opening surface 13g to generate an image that makes it easy to grasp the outline of the opening surface 13g. Note that if the outline of the opening surface 13g can be grasped, image processing may be omitted.

[0106] In step S34, the control unit 60 calculates the cutting path on the opening surface 13. The control unit 60 acquires the coordinates of four points A to D that are vertices of a rectangle that is the outline of the opening surface 13g in the image CI after image processing shown in FIG. 5. Two points in the longitudinal direction among the four points A to D, that is, the midpoints E and F of the points A and B and the points C and D, are acquired, and a line connecting the midpoints E and F is acquired as the measurement path of the first tape 17. The control unit 60 acquires the first measurement path in the XYZ coordinates of the control coordinate system using the image system coordinates of the measurement path of the first tape 17 (hereinafter also referred to as the "first measurement path") and the focal length between the camera 50 and the opening surface 13, etc. The control unit 60 also acquires two points on the left and right, that is, the lines connecting the points A and B and the points C and D, as the measurement path of the second tape 18 (hereinafter also referred to as the "second measurement path"). The control unit 60 acquires the second measurement path in XYZ coordinates of the control coordinate system using the image system coordinates of the second measurement path and the focal length between the camera 50 and the opening surface 13. Note that the Z coordinate value is a constant value in each control system coordinate of the first measurement path and the second measurement path.

[0107] In step S35, the control unit 60 determines whether or not the cutting path L1 is within the operating range WS of the robot 40. The control unit 60 stores in the memory 63 table data that associates information on whether or not the cutting path of the box 12 is within the operating range WS of the robot 40 with the box size. The control unit 60 determines whether or not the cutting path L1 is within the operating range WS by referring to the table data based on the box size information of the target box 12 at that time. If the cutting path L1 is within the operating range WS, the control unit 60 proceeds to step S36, and if the cutting path L1 is not within the operating range WS, the control unit 60 proceeds to step S37.

[0108] Here, in this embodiment, for the first cutting path L1, it is determined that the cutting path is within the operating range WS of the robot 40 for all sizes of boxes 12 at the work position SP. Also, for the second cutting path L2, it is determined that the second cutting path is within the operating range WS of the robot 40 for boxes 12 belonging to small sizes that are in a range of not less than the minimum size and not more than a predetermined threshold size. Also, it is determined that the second cutting path L2 is not within the operating range WS of the robot 40 for boxes 12 belonging to large sizes that are in a range of not less than the predetermined threshold size and not more than the maximum size. In this way, the cutting control of the tapes 17, 18 is different between boxes 12 belonging to large sizes and boxes 12 belonging to small sizes. Note that if the first cutting path L1 is within the operating range WS of the robot 40 for all box sizes, the determination process of step S35 for the first cutting path L1 can be omitted.

[0109] <Tape cutting on large boxes> The following will first describe an example of a large-sized box 12. Since the first cutting path L1 for the maximum-sized box 12 is within the working range WS of the robot 40, the control unit 60 proceeds to step S36.

[0110] In step S36, the control unit 60 uses the distance sensor 55 to measure the distance to the tape 17 along the cutting path. The control unit 60 drives the arm 43 of the robot 40, and while keeping the distance sensor 55 at a height position (coordinate Z1) a predetermined distance away from the opening surface 13 as shown in FIG. 17, the control unit 60 places the head 44 in a vertical position, thereby positioning the distance sensor 55 in a direction that allows the distance sensor 55 to point to the cutting path L1 (see FIG. 3 and FIG. 7) on the opening surface 13 as a measurement target. The control unit 60 moves the head 44 in the vertical position along the first measurement path (XY coordinates). During this movement process, the distance sensor 55 measures the distance LZ in the vertical direction Z to the first tape 17 at multiple points along the cutting path L1. The distances LZ in the vertical direction Z at these multiple points indicate the positional changes in the vertical direction Z of the first cutting path L1. The control unit 60 determines a cutting path (XYZ coordinates) expressed in control system coordinates of the first tape 17, based on information on the first measurement path (XY coordinates), the position coordinate Z1 in the vertical direction Z at the time of measurement by the distance sensor 55, and the distance LZ of multiple points in the vertical direction Z which are the measurement results of the distance sensor 55. The control system coordinates (XYZ coordinates) of this cutting path reflect the position change in the vertical direction Z of the cutting path of the first tape 17. After completing measurement by the distance sensor 55, the control unit 60 proceeds to the next step S38.

[0111] In step S38, control unit 60 cuts tape 17 while controlling the height of cutter 53 in accordance with the distance detected by distance sensor 55. That is, control unit 60 controls the position of cutter 53 along a cutting path (XYZ coordinates) of first tape 17 expressed in control system coordinates. At this time, the position of cutter 53 is also controlled in vertical direction Z during the cutting process of first tape 17.

[0112] As shown in Fig. 18, even if first tape 17 is curved because opening surface 13 of box 12 is recessed, cutter 53 is position-controlled in vertical direction Z, so cutter 53 moves along a cutting path on curved first tape 17 as indicated by a dashed-dotted arrow in Fig. 18. As a result, the necessary cutting depth for cutter 53 is ensured over the entire length of first tape 17, and first tape 17 is cut reliably.

[0113] When the first cutting path is not within the operating range WS, in step S37, the control unit 60 measures the distance to the tape 17 along the cutting path by the distance sensor 55 while transporting the box 12. After the measurement by the distance sensor 55 is completed in step S37, the process proceeds to the next step S39. In step S39, the control unit 60 cuts the tape 17 while controlling the height of the cutter 53 according to the detected distance by the distance sensor 55 while transporting the box 12. For example, when even a part of the first cutting path of a large-sized box 12 is not within the operating range WS, the first tape 17 is cut by one of the following three methods. In the first method, the box 12 is transported on the conveyor 83 in the transport direction X, and the first tape 17 is cut into two parts in the longitudinal direction at different positions before and after the transport, so that the first tape 17 is cut in two parts. In the second method, the first tape 17 is cut by controlling the position of the cutter 53 in the width direction Y and vertical direction Z while transporting the box 12 at a constant speed. In the third method, the first tape 17 is cut by moving the cutter 53 in the opposite direction to the transport direction of the box 12 based on the XY coordinates of the first cutting path while transporting the box 12 at a constant speed. Note that in step S36, measurement is also performed by the distance sensor 55 using the above three methods.

[0114] In step S40, control unit 60 determines whether or not box 12 has been opened. At the stage where first tape 17 has been cut, second tape 18 has not yet been cut, so box 12 has not been opened. Therefore, control unit 60 proceeds to the process of step S41.

[0115] In step S41, the control unit 60 switches to the next cutting path. In this example, when cutting of the first tape 17 is finished, the control unit 60 then switches to the cutting path for one of the two second tapes 18 that should be cut first. After switching the cutting path, the control unit 60 returns to the process of step S35. In this manner, the control unit 60 repeatedly executes the processes of steps S35 to S39 for each cutting path until opening of the box 12 is completed in step S40. In this example, the tape is H-patterned and there are three cutting paths for cutting the three tapes 17, 18, so the control unit 60 repeatedly executes the processes of steps S35 to S39 three times.

[0116] In the case of a large-sized box 12, a part of the opening surface 13 at the work position SP on the conveyor 83 lies outside the working range WS. In step S35, the control unit 60 determines whether or not one cutting path L2 is within the operating range WS of the robot 40. The control unit 60 determines whether or not one cutting path L2 is within the operating range WS by referring to table data based on information about the box size of the currently targeted box 12. If the box 12 is large, the control unit 60 determines that one cutting path L2 is not within the operating range WS, and proceeds to step S37.

[0117] In step S37, the control unit 60 measures the distance to one of the second tapes 18 along the cutting path L2 by the distance sensor 55 while transporting the box 12. First, the control unit 60 drives the conveyor 83 to move the box 12 in the transport direction X until one of the second cutting paths L2 enters the operating range WS of the robot 40. In this example, the box 12 is moved from the work position SP in the second direction X2. As a result, the box 12 is placed at the first transport position shown by the solid line in FIG. 19. At this first transport position, the second tape 18 on the right side of the box 12 in FIG. 19 enters the operating range WS of the robot 40. Then, the control unit 60 drives the arm 43 of the robot 40 to keep the distance sensor 55 at a height position (coordinate Z1) a predetermined distance away from the opening surface 13, while placing the head 44 in a vertical position, thereby placing the distance sensor 55 in a direction that allows it to be oriented to the cutting path L2 (see FIG. 3 and FIG. 7) on the opening surface 13 as a measurement target. The control unit 60 moves the head 44 in the upright position along a second measurement path (XY coordinates) in the width direction Y, which is different from the traveling direction in FIG.

[0118] During this movement process, the distance sensor 55 measures the distance LZ in the vertical direction Z to the second tape 18 at multiple points along the cutting path L2. These multiple points' distances LZ in the vertical direction Z indicate the positional changes in the vertical direction Z of the second cutting path L2. The control unit 60 determines the cutting path (XYZ coordinates) expressed in the control system coordinates of the second tape 18 based on the second measurement path (XY coordinates), the position coordinate Z1 in the vertical direction Z at the time of measurement by the distance sensor 55, and the multiple points' distances LZ in the vertical direction Z that are the measurement results of the distance sensor 55. The control system coordinates (XYZ coordinates) of this cutting path reflect the positional changes in the vertical direction Z of the second tape 18. It is preferable that the second measurement path is measured along a position that allows for a predetermined margin inside the edge of the box 12. This makes it possible to measure the opening surface 13 of the box 12 even if the box 12 is deformed, unless the deformation is excessive.

[0119] In the next step S39, the control unit 60 cuts one of the second tapes 18 while controlling the height of the cutter 53 in accordance with the distance detected by the distance sensor 55, accompanied by the transport operation of the box 12. That is, the control unit 60 controls the position of the cutter 53 along the cutting path (XYZ coordinates) of one of the second tapes 18 expressed in control system coordinates. At this time, the position of the cutter 53 is also controlled in the vertical direction Z during the cutting process of the second tape 18. Note that in this step S39, which targets the second cutting path, the transport operation was performed in the previous step S37, and the entire second cutting path is already within the operating range WS of the robot 40, so the transport operation is omitted.

[0120] 19 is positioned along cutting path L2, which is represented by the control system coordinate system, in a position inclined at an angle with respect to one of the second tapes 18. At this time, even if the second tape 18 is curved because the opening surface 13 of the box 12 is recessed, the position of the cutter 53 is controlled in the vertical direction Z, so that the cutter 53 moves along cutting path L2 on the curved second tape 18. As a result, the necessary cutting depth for the cutter 53 is ensured over the entire length of the second tape 18, and the second tape 18 is reliably cut.

[0121] In step S40, the control unit 60 determines that the box 12 has not been opened, and therefore switches to the next cutting path in step S41. That is, switches to cutting path L2 of the other, second tape 18. Then, the control unit 60 returns to the process of step S35.

[0122] In step S35, the control unit 60 determines whether or not the other cutting path L2 is within the operating range WS of the robot 40. The control unit 60 determines that the other cutting path L2 is not within the operating range WS by referring to the table data based on the box size information of the target box 12 at that time, and therefore proceeds to step S37.

[0123] In step S37, the control unit 60 measures the distance to the other second tape 18 along the cutting path L2 by the distance sensor 55 while transporting the box 12. First, the control unit 60 drives the conveyor 83 to move the box 12 in the transport direction X until the other second cutting path L2 enters the operating range WS of the robot 40. In this example, the control unit 60 moves the box 12 from the first transport position in the first direction X1. As a result, the box 12 is disposed at the second transport position shown by the two-dot chain line in FIG. 19. At this second transport position, the second tape 18 on the left side of the box 12 in FIG. 19 enters the operating range WS of the robot 40. Then, the control unit 60 drives the arm 43 of the robot 40 to keep the distance sensor 55 at a height position (coordinate Z1) a predetermined distance away from the opening surface 13, and places the head 44 in a vertical position, thereby disposing the distance sensor 55 in a direction that allows it to be oriented to the cutting path L2 (see FIG. 3 and FIG. 7) on the opening surface 13 as a measurement target. The control unit 60 moves the head 44 in the upright position along a second measurement path (XY coordinates) in the width direction Y, which is different from the traveling direction in FIG.

[0124] During this movement process, the distance sensor 55 measures the distance LZ in the vertical direction Z to the other second tape 18 at multiple points along the cutting path L2. As with the aforementioned one of the second cutting paths, the control unit 60 uses information on the distance LZ at multiple points in the vertical direction Z, which are the measurement results of the distance sensor 55, to determine the cutting path (XYZ coordinates) of the second tape 18, which is expressed in the control system coordinates. The control system coordinates of this cutting path reflect the positional change in the vertical direction Z of the second tape 18.

[0125] In the next step S39, the control unit 60 cuts the other second tape 18 while controlling the height of the cutter 53 in accordance with the distance detected by the distance sensor 55. That is, the control unit 60 controls the position of the cutter 53 along a cutting path (XYZ coordinates) of the other second tape 18 expressed in control system coordinates. At this time, the position of the cutter 53 is also controlled in the vertical direction Z during the cutting process of the second tape 18.

[0126] 19 is positioned along cutting path L2, which is represented by the control system coordinate system, in a position inclined at an angle relative to the other second tape 18. At this time, even if the second tape 18 is curved because the opening surface 13 of the box 12 is recessed, the position of the cutter 53 is controlled in the vertical direction Z, so that the cutter 53 moves along the cutting path L2 on the curved second tape 18. As a result, the necessary cutting depth for the cutter 53 is ensured over the entire length of the second tape 18, and the second tape 18 is reliably cut.

[0127] When the second cutting path L2 is the target, in step S37, the distance sensor 55 may measure the distance in the conveying direction X to the portion of the second tape 18 attached to the side surface 12B of the box 12 instead of or in addition to the distance in the vertical direction Z, and the measurement result may be used to determine the cutting path L2 expressed in control system coordinates reflecting the position change of the second tape 18 in the conveying direction X. By controlling the position of the cutter 53 along this cutting path L2, even if the second tape 18 is curved because the side surface 12B of the box 12 is recessed or bulged, the position of the cutter 53 is controlled in the conveying direction X, so that the cutter 53 moves along the cutting path L2 on the curved second tape 18. As a result, even if the side surface 12B of the box 12 is curved, the necessary cutting depth for the cutter 53 is ensured throughout the entire longitudinal area of ​​the second tape 18, and the second tape 18 is reliably cut.

[0128] When the three tapes 17, 18 are cut in this manner, the large-sized box 12 is opened. Therefore, in step S40, the control unit 60 determines that the box 12 has been opened, and ends the tape cutting control.

[0129] <Tape cutting on small size boxes> Next, an example of a small-sized box 12 will be described. As shown in Fig. 14, in the case of a small-sized box 12, the entire opening surface 13 of the box 12 at the working position SP on the conveyor 83 at the working height position H2 is located within the operating range WS of the robot 40. In step S35 in Fig. 20, the control unit 60 determines that the cutting path L1 is within the operating range WS of the robot 40, and therefore proceeds to step S36.

[0130] In step S36, the control unit 60 uses the distance sensor 55 to sequentially measure the distance to the first tape 17 along the cutting path L1. This measurement method is the same as that for the large-sized box 12, and the control unit 60 drives the arm 43 of the robot 40 to move the distance sensor 55 along the first measurement path (XY coordinates) in a posture in which the measurement target is directed downward, while keeping the distance sensor 55 at a height position (coordinate Z1) a predetermined distance away from the opening surface 13, even in the case of a small-sized box 12. The control unit 60 determines a cutting path (XYZ coordinates) expressed in control system coordinates that reflects the position change in the vertical direction Z of the cutting path of the first tape 17, based on information on the first measurement path (XY coordinates), the position coordinate Z1 in the vertical direction Z at the time of measurement by the distance sensor 55, and the distance LZ of multiple points in the vertical direction Z that are the measurement results of the distance sensor 55.

[0131] In the next step S38, the control unit 60 cuts the tape 17 while controlling the height of the cutter 53 in accordance with the distance detected by the distance sensor 55. That is, the control unit 60 controls the position of the cutter 53 along a cutting path (XYZ coordinates) of the first tape 17 represented in control system coordinates. At this time, the position of the cutter 53 is also controlled in the vertical direction Z during the cutting process of the first tape 17.

[0132] As with the large-sized box 12 shown in Fig. 18, in the case of a small-sized box 12, even if the opening surface 13 of the box 12 is recessed and the first tape 17 is curved, the position of the cutter 53 is controlled in the vertical direction Z, so that the cutter 53 moves along a cutting path on the curved first tape 17 as indicated by a dashed-dotted arrow in Fig. 18. As a result, the necessary cutting depth for the cutter 53 is ensured over the entire length of the first tape 17, and the first tape 17 is cut reliably.

[0133] Next, after switching the target to the second cutting path (step S41), in step S35, the control unit 60 determines that the second cutting path L2 is within the operating range WS of the robot 40. Therefore, in step S36, the control unit 60 measures the distance to one of the second tapes 18 along the cutting path L2 with the distance sensor 55. While the box 12 is at the work position SP on the conveyor 83, the control unit 60 drives the arm 43 of the robot 40 to keep the distance sensor 55 at a height position (coordinate Z1) a predetermined distance away from the opening surface 13, and places the head 44 in a vertical position, thereby positioning the distance sensor 55 in a direction that allows it to point to the measurement target below. The control unit 60 moves the head 44 in the vertical position along the second measurement path (XY coordinates) in the width direction Y, which is different from the traveling direction in FIG. 17.

[0134] During this movement process, the distance sensor 55 measures the distance LZ in the vertical direction Z at multiple points along the cutting path L2 to one of the second tapes 18. Using information on the distance LZ at multiple points in the vertical direction Z that is the measurement result of the distance sensor 55, the control unit 60 determines the cutting path (XYZ coordinates) of the second tape 18 expressed in the control system coordinates, reflecting the positional change of the second tape 18 in the vertical direction Z.

[0135] In the next step S38, the control unit 60 cuts one of the second tapes 18 while controlling the height of the cutter 53 in accordance with the distance detected by the distance sensor 55. That is, the control unit 60 controls the position of the cutter 53 along a cutting path (XYZ coordinates) of one of the second tapes 18 expressed in control system coordinates. At this time, the position of the cutter 53 is also controlled in the vertical direction Z during the process of cutting the second tape 18.

[0136] In the example of a large-sized box 12 shown in FIG. 19, the box 12 cuts two second tapes 18 at two different conveying positions in the conveying direction X, but in the case of a small-sized box 12, both second tapes 18 are located within the operating range WS of the robot 40. Therefore, while remaining at the working position SP on the conveyor 83, the head 44 is position-controlled along the cutting path L2 represented by the control system coordinate system in an attitude inclined obliquely with respect to one of the second tapes 18. At this time, even if the second tape 18 is curved because the opening surface 13 of the box 12 is recessed, the cutter 53 is position-controlled in the vertical direction Z and moves along the cutting path L2 on the curved second tape 18. As a result, the necessary cutting depth for the cutter 53 is ensured over the entire area of ​​the second tape 18 in the longitudinal direction, and the second tape 18 is reliably cut.

[0137] Then, for the other second tape 18, it is determined that the other second cutting path is within the operating range WS of the robot 40 (positive determination in step S35). In step S36, the control unit 60 measures the distance to the second tape 18 along the cutting path L2 with the distance sensor 55. In the next step S38, the control unit 60 cuts the other second tape 18 while controlling the height of the cutter 53 in accordance with the distance detected by the distance sensor 55.

[0138] When all of the tapes 17, 18 of the box 12 have been cut in this way and the box 12 has been opened, the control unit 60 drives the motor 92 of the lifting unit 87 to lower the conveyor 83 from the working height position to the standby position H0. Then, the conveyors 81 to 83 are driven, so that the opened box 12 is carried out from the conveyor 83 to the carry-out conveyor 82, and the next box 12 to be opened is carried from the carry-in conveyor 81 onto the conveyor 83. Thereafter, the boxes 12 carried onto the conveyor 83 are similarly opened one by one.

[0139] According to the third embodiment, in addition to the corresponding effects in the first embodiment, the following effects can be obtained. (8) The opening device 11 includes a camera 50 (an example of an imaging unit), an articulated robot 40 having an arm 43 with a cutter 53 attached to its tip and controlled by a control unit 60, and a lifting mechanism 86 that lifts the box 12 until the opening surface 13 of the box 12 reaches a height position where the camera 50 can focus on the opening surface 13. The camera 50 is fixed at a predetermined height position where the camera 50 can capture an image of the opening surface 13 of the box 12. Therefore, it is not necessary to move the camera 50 when capturing an image of the opening surface 13. In addition, if the lifting mechanism 86 is set so that the camera 50 focuses on the opening surface 13 when the opening surface 13 is located at a height position where the movable range of the arm 43 with the cutter 53 attached to its tip is wide, the maximum size of the box 12 that the cutter 53 can cut the tapes 17 and 18 can be increased.

[0140] (9) The opening device 11 includes a conveyor 83 (an example of a conveying mechanism) that conveys the box 12 horizontally along the longitudinal direction of the tapes 17 and 18. When a part of the tapes 17 and 18 is within the movable area of ​​the cutter 53 determined by the operating range WS of the robot 40, and another part of the tapes 17 and 18 is not within the movable area, the control unit 60 performs the following cutting control. That is, the cutter 53 cuts the part of the tapes 17 and 18, and cuts the other part of the tapes 17 and 18 by the cutter 53 while carrying the box 12 horizontally until the other part of the tapes 17 and 18 is located within the operating range WS of the robot 40. For example, when a part of the first cutting path L1 is outside the operating range WS of the robot 40, the first tape 17 is cut by the cutter 53 while carrying the box 12 in the carrying direction X, which is also the longitudinal direction of the first tape 17. Also, for example, when a part of the second cutting path L2 is outside the operating range WS of the robot 40, the box 12 is transported by the conveyor 83, and the two second tapes 18 are cut in a state where the box 12 is disposed at two different positions, the first transport position and the second transport position. Therefore, even for a large-sized box 12 in which even a part of the tapes 17, 18 is outside the movable range of the cutter 53, the tapes 17, 18 can be cut by transporting the box 12 horizontally. The maximum size of the box 12 that can cut the tapes 17, 18 can be increased in relation to the movable range of the arm 43 of the robot 40. In other words, the opening device 11 can be configured compact in relation to the maximum size of the box that can be opened.

[0141] (10) When cutting first tape 17, in the case of a large-sized box 12 that is larger than the size threshold, control unit 60 causes conveyor 83 to transport box 12 in transport direction X, which is the longitudinal direction of first tape 17. This makes it possible to increase the maximum size of box 12 that can be opened by cutting tapes 17, 18 relative to the movable area of ​​arm 43 of robot 40.

[0142] (11) One first tape 17 and two second tapes 18 are attached to the opening surface 13 with their longitudinal directions intersecting each other. For a large-sized box 12 larger than the size threshold, the control unit 60 places the box 12 at two different transport positions while the conveyor 83 transports it, and the cutter 53 cuts each of the two second tapes 18 at the two different transport positions. The maximum size of the box 12 that can be opened by cutting the tapes 17 and 18 can be increased relative to the movable area of ​​the arm 43 of the robot 40.

[0143] The embodiment is not limited to the above and may be modified as follows. As shown in FIG. 22, in the configuration of the head 44 without a roller, the control unit 60 may control the inclination angle of the cutter 53, which is the angle that the axis of the cutter 53 makes with respect to the tape surface, during the process in which the cutter 53 cuts the tapes 17, 18. The inclination angle of the tape surface with respect to the horizontal plane is calculated based on the change in the position of the vertical direction Z of the tape surface according to the distance to the tape surface measured by the distance sensor 55 moving along the cutting path of the tapes 17, 18, and the inclination angle of the cutter 53 is controlled according to the inclination angle of the tape surface so that the inclination angle of the cutter 53 with respect to the tape surface falls within an appropriate allowable range. The control unit 60 controls the arm 43 of the robot 40 to control the inclination angle of the head 44. Alternatively, an actuator for changing the inclination angle of the cutter 53 may be provided in the head 44, and the control unit 60 may control the inclination angle of the cutter 53 by controlling the actuator. The inclination angle of cutter 53 may be controlled so that the angle it forms with the tape surface is always constant, or if the angle it forms with the tape surface falls outside the allowable range, the inclination angle of cutter 53 may be controlled so that it falls within the allowable range.

[0144] Fig. 21 shows a comparative example in which the control unit cuts the tapes 17, 18 while keeping the inclination angle θh of the cutter 53 constant with respect to the horizontal plane. As shown in Fig. 21, if the inclination angle θh of the cutter 53 is constant, as shown in the figure, the angle θt between the cutter 53 and the tape surface 17A becomes too small compared to the appropriate range in the portion where the tapes 17, 18 are greatly inclined with respect to the horizontal plane due to the curvature of the tearing surface 13 to which the tape 17 is attached, and there is a concern that a large load will be applied to the cutter 53 when cutting the tape. In this case, the cutting ability of the cutter 53 to cut the tapes 17, 18 will be reduced, and there is a concern that the life of the cutter 53 will be shortened due to early wear or breakage.

[0145] In contrast, in the embodiment shown in FIG. 22, the control unit 60 controls the inclination angle θc of the cutter 53 relative to the tape surfaces 17A, 18A to fall within the allowable range in response to the change in the distance to the tape 17, 18 detected by the distance sensor 55 during the process in which the cutter 53 cuts the tape 17, 18. The control unit 60 changes the angle θh between the cutter 53 and the horizontal plane, so that the inclination angle θc between the cutter 53 and the tape surfaces 17A, 18A falls within the appropriate allowable range even in the portion in which the tape 17, 18 is greatly inclined relative to the horizontal plane due to the curvature of the opening surface 13 to which the tape 17 is attached, as shown in FIG. 22. Therefore, a large load is not likely to be applied to the cutter 53 when the tape is cut. This improves the cutting ability of the tape 17, 18, and prevents early wear and damage to the cutter 53, leading to a longer life for the cutter 53.

[0146] The position detection unit is not limited to the lift-type height detection device 30 in which the sensor unit 32 moves in the height direction Z, but may be a mobile detection device in which the sensor unit 32 moves in the X direction or Y direction. By placing the box sideways, the position of the tape in the cross direction intersecting with the opening surface 13 can be detected.

[0147] In the first embodiment, both the height detection device 30 as an example of a position detection unit and the distance sensor 55 may be provided. The cutting paths L1, L2 are obtained using the position of the opening surface 13 in the intersecting direction detected by the height detection device 30. The distance sensor 55 detects the distance to the tapes 17, 18, and controls the position of the cutter 53 in the intersecting direction when cutting the tapes 17, 18. As a result, the opening operation of cutting the tapes 17, 18 to open the box 12 can be processed at high speed, and even the tapes 17, 18 that are curved due to a dent in the opening surface 13 can be cut reliably.

[0148] The configuration is not limited to the case where the box 12 is opened with the opening surface 13 of the box 12 facing upward. The box 12 may be opened with the opening surface 13 facing sideways, or with the opening surface 13 facing downward. Even in such a case, the position of the tapes 17, 18 in the cross direction crossing (for example, perpendicular to) the opening surface 13 of the box 12 to which the tapes 17, 18 are attached is detected by the position detection unit, and the cutting path on the opening surface 13 is obtained from the outline of the opening surface 13g in the image captured by the camera 50 of the opening surface 13 of the box 12 to which the tapes 17, 18 are attached. As a result, the position of the cutter 53 can be appropriately controlled based on the positions of the tapes 17, 18 in the cross direction (for example, the X direction or Y direction) and the cutting path on the opening surface 13, to appropriately cut the tapes 17, 18.

[0149] For example, the robot 40 may grip the box 12 with an arm 43, control the orientation of the box 12 with the arm 43, and orient the opening surface 13 toward a fixed camera 50 to cause the camera 50 to capture an image of the opening surface. Alternatively, the robot 40 may control the orientation of the box, orient the box in a direction that allows detection of the cross-directional position of the tape with respect to detection light from a position detection unit, and cause the position detection unit to detect the cross-directional positions of the tapes 17, 18 affixed to the opening surface 13 of the box 12. Alternatively, the robot 40 may grip the box 12 and move the box 12 relative to a fixed cutter 53 to cut the tapes 17, 18 affixed to the opening surface 13 with the cutter 53.

[0150] Based on box identification information such as the box product number, the height position of the camera 50, i.e., the distance from the camera 50 to the opening surface 13g when imaged from a predetermined imaging position height, may be obtained. In this case, the height detection device 30 or the distance sensor 55 can be eliminated. In this configuration, an example of a position detection unit is constituted by the camera 50 and a calculation unit 62 that calculates the distance from the camera 50 to the opening surface 13 using the image captured by the camera 50 and box identification information that defines the size of the opening surface 13 of the box 12.

[0151] In the second embodiment, in the cutting process in which the cutter 53 cuts the second tape 18, the distance sensor 55 may detect the distance to the side surface 12B of the box 12 or the second tape 18 on the side surface 12B instead of the opening surface 13. With this configuration, the position of the cutter 53 can be controlled to follow the curvature of the side surface 12B, and the second tape 18 can be appropriately cut even if the side surface 12B is curved. Note that multiple distance sensors may be provided, and in the cutting process in which the second tape 18 is cut, the distance to the opening surface 13 and the distance to the side surface 12B may be measured by the two distance sensors 55, respectively, and the cutter 53 may be moved in the width direction Y while being position-controlled in the height direction Z and the X direction to cut the second tape 18. With this configuration, the second tape 18 can be more appropriately cut by following the curvature of the opening surface 13, such as a recess, and the curvature of the side surface 12B, such as a recess.

[0152] In the second embodiment, before cutting the tape, the distance sensor 55 is first moved along the cutting path L1 with the cutter 53 separated from the tape, and information on the correspondence between the position in the X direction and the distance LZ to the tape 17 is acquired. After that, based on the acquired information, the cutter 53 may be moved along the cutting path L1 while controlling the position in the intersecting direction (height direction Z), and the tape 17 may be cut.

[0153] In each of the above-described embodiments, the cutter unit 51 may be supported by an air cylinder, and while a small air pressure is applied to the air cylinder, a roller as an example of a rolling body is pressed against the opening surface 13 or the side surface 12B, and the cutter 53 is controlled in position to follow the surface shape of the opening surface 13 or the side surface 12B, thereby cutting the tapes 17, 18. With this configuration, even if there is a recess on the opening surface 13 or the side surface 12B of the box 12, the cutter 53 can be made to follow the recess on the opening surface 13 or the side surface 12B to cut the tapes 17, 18. Note that instead of a roller as an example of a rolling body, a ball or a roller may be used.

[0154] In the second and third embodiments, the distance sensor 55 measures the distance in the vertical direction Z along the length of the first tape 17, but the distance in the vertical direction Z may also be measured in the width direction of the first tape 17. For example, when the tape 17 is applied in a state where a pair of flaps 16 overlap, a step may be formed in the width direction of the tape 17. By measuring the distance in the vertical direction Z along the width direction of the tape, the step between the overlapping flaps 16, 16 is detected. At the step, the tape 17 is raised above the lower flap 16, and this raised portion of the tape 17 is cut. In this case, the cutter 53 cuts the tape 17 and does not cut the flap 16 much, so that the cutter 53 is less subjected to a cutting load, which contributes to a longer life of the cutter 53.

[0155] In the method of determining the four corners of the outline of the opening surface 13 as the four vertices, if the ends of the tapes 17 and 18 extend outward from the box 12, the image processing may erroneously detect the tips of the ends of the tapes 17 and 18 as vertices. In this case, if the cutting path is determined from the erroneously detected vertices, it may cause an error in the distance measurement by the distance sensor 55 or an error in cutting the tapes 17 and 18. In particular, the second tape 18 is more likely to be cut incorrectly than the first tape 17. Also, the first tape 17 can be opened even if a straight line connecting the midpoints is used as the cutting path, but the second tape may not be cut due to deformation of the box. In other words, since I-pasting is only the first tape, it can be cut even if the cutting path is straight, but in the case of H-pasting, if the box 12 is deformed and the sides of the opening surface 13 are curved, the second tape 18 may not be cut if a straight line connecting the vertices of the rectangle of the opening surface 13 is used as the cutting path. Therefore, the cutting path is determined as a straight line connecting the midpoints of each of the four vertices, and in H-pasting, the vertex is determined as the intersection of the extended lines of some of the straight line sections, such as the centers of the four sides that form the outline of the opening surface.

[0156] In this case, the method of determining the outline of the opening surface 13 may be switched between H-pasting, which includes the second tape 18, and I-pasting, which does not include the second tape 18. For this reason, in I-pasting, the four corners of the outline of the opening surface 13 are taken as four vertices, and the cutting path is determined by straight lines connecting the midpoints of two of the four vertices that face each other in the direction intersecting with the first tape 17, while in H-pasting, the vertices are determined by the intersections of extension lines of some straight line portions, such as the central parts of the four sides that form the outline of the opening surface 13.

[0157] In the third embodiment, an example of the transport mechanism may be a conveyor 83 without a lifting function, instead of the lifting type conveyor 83. For example, if the motion range WS of the robot 40 is sufficiently wide compared to the box size, or if the conveyor 83 is disposed at a height position where the opening surface 13 of the largest size box 12 is located near the height position where the motion range WS of the robot 40 is at its widest, the tapes 17, 18 of the box 12 can be cut even without a lifting function.

[0158] In the third embodiment, the conveyor 83 is raised from the standby position H0 by the lifting mechanism 86 to position the opening surface 13 of the box 12 at the focal position of the camera 50, but the conveyor 83 may be lowered from the standby position H0 by the lifting mechanism 86 to position the opening surface 13 of the box 12 at the focal position of the camera 50. In this case, as long as the opening surface 13 can be positioned at a height position where the operating range WS of the robot 40 is wider than when it is at the standby position H0, the movement from the standby position to the working height position may be either upward or downward.

[0159] A mechanical sensor may be provided. Examples of mechanical sensors include a load cell. A measuring roller is provided in the cutter unit at a location separate from the pair of rollers that limit the amount of insertion of the cutter. The roller is pressed against the opening surface while rolling over the opening, and the roller's height is adjusted with the arm while the roller is moved to maintain a constant pressure or strain on the arm, thereby measuring the shape of the tape along the longitudinal direction on the opening surface. Such a contact sensor may be used to measure the shape of the tape.

[0160] In the third embodiment, the working range WS, which is the working range of point P of the robot 40, is regarded as the movable range of the cutter 53 when the head 44 is attached to the arm, but the actual movable range of the cutter 53 derived from the position of the tape to be cut and the posture of the robot 40 when cutting the tape may be regarded as the movable range of the cutter 53. In this case, since the movable range of the cutter 53 is wider than the working range WS, it is possible to increase the size of the box in which the tape cutting operation is performed without transporting the box 12.

[0161] In the third embodiment, as in the second embodiment, in the process of cutting the tapes 17, 18, the distance sensor 55 may measure the distance to a position ahead of the cutter 53 in the traveling direction, and the position of the cutter 53 may be controlled in the vertical direction Z along the cutting path based on the measured distance.

[0162] In the first and second embodiments, the camera 50 as an example of an imaging unit may be fixed at a predetermined height above a work position that is higher than the opening surface 13. The second tape 18 may be cut before the first tape 17.

[0163] The box is not limited to a rectangular prism, but may be a polygonal prism such as a triangular prism. The height detection unit is not limited to a height detection device separate from the robot, and may be attached to the arm 43 or head 44 of the robot 40. In this case, a non-contact detection unit may be used that irradiates the opening surface 13 with detection light or sound waves from above the opening surface 13, detects the reflected light or sound waves, and detects the distance to the opening surface 13 to detect the height position of the opening surface 13.

[0164] The robot 40 is not limited to a multi-joint robot such as a vertical multi-joint type or a horizontal multi-joint type, but may be an industrial robot using other mechanisms such as a Cartesian coordinate type, a cylindrical coordinate type, a polar coordinate type, or a parallel link type.

[0165] The opening device of each of the above-described embodiments may not include the robot 40. For example, the opening device 11 may include a position detection unit that detects the position of the tapes 17, 18 in a direction intersecting (for example, perpendicular to) the opening surface 13 of the box 12, an imaging unit that images the opening surface of the box, a cutting mechanism having an actuator that moves the cutter 53, and a control unit 60. Also, for example, the opening device 11 may include a fixed cutter 53 and a configuration in which the tapes 17, 18 attached to the opening surface 13 of the box 12 are cut by moving the box 12 relative to the cutter 53.

[0166] The cutter is not limited to an ultrasonic vibration type, but may be a cutter that physically cuts with a blade. The box 12 may be closed in a so-called "vertical" manner by a first tape 17 applied along the center line of the opening surface 13. The box 12 may also be closed in a so-called "cross" manner by a first tape applied along a first center line extending vertically on the opening surface 13 and a second tape applied along a second center line extending horizontally on the opening surface 13 in a state where it intersects with the first tape.

[0167] The tapes 17 and 18 are not limited to adhesive tapes, and may be tapes attached to the box 12 with glue or an adhesive. The tapes 17 and 18 may also be welded to the box 12. An inspection unit may be provided that captures an image of the cutter 53 with the camera 50 or another camera and inspects the cutter for damage based on the captured image. For example, the camera 50 is attached to the head 44 via a tilting mechanism so that the imaging direction can be changed, and the camera 50 captures images of the cutter 53 on a regular or irregular basis. The inspection unit inspects the cutter 53 for damage and wear based on the image of the cutter 53. With this configuration, damage and wear to the cutter 53 can be detected at an early stage.

[0168] The boxes are not limited to cardboard boxes made of paper, but can also be plastic cardboard boxes. [Explanation of symbols]

[0169] 10...box opening system, 11...box opening device, 12...box, 12B...side as an example of an adjacent surface, 12K...opening, 12g...box in image, 13...opening surface, 13g...opening surface in image, 16...flap, 17...first tape as an example of a tape, 18...second tape as an example of a tape, 20...conveying device, 21...conveyor, 22...positioning device, 23...stopper device, 24...guide device, 26...stopper, 28...guide member, 29...sensor, 30...height detection device as an example of a position detection unit, 31...lifting mechanism as an example of a first moving mechanism, 32...sensor unit, 40...robot as an example of a second lifting mechanism, 43...arm, 44...head, 50...camera as an example of an imaging unit, 51...cutter unit, 53...cutter, 55...distance sensor, 60...control unit, 61...image processing unit, 62...calculation unit, 63...memory, 70...operation panel, 71...display unit, 83...conveyor as an example of a conveying mechanism, 83M...motor, 85...conveyor belt, 86...lifting mechanism, 87...lifting unit, 88...guide rod, 89...slider, 90...support table, 92...motor, 93...power transmission mechanism, 97...drive belt, 100...timing belt, HL...detection light, CI...image (captured image), A, B, C, D...vertices, E, F...midpoints, L1...first cutting path as an example of a cutting path, L2...second cutting path as an example of a cutting path, EL...edge line, LZ...distance, H0...waiting position, H1...working height position, WS...operation range, X...conveying direction, X1...conveying direction, Y...Y direction (width direction), Z...Z direction (height direction) as an example of an intersecting direction.

Claims

1. A box opening device for opening a box by cutting a tape attached along a periphery of a flap that closes an opening of the box, comprising: a position detection unit that detects a position of the tape in a direction intersecting with the opening surface of the box to which the tape is attached; a detection unit that detects the opening surface from a position away from the box and acquires detection information necessary to identify a cutting path of the tape; a cutter that moves relative to the box to cut the tape; a control unit that identifies a cutting path of the tape based on the detection information and cuts the tape by controlling the position of the cutter along the identified cutting path, The position detection unit detects a plurality of positions of the tape in the cross direction along the cutting path, The control unit controls the position of the cutter in the cross direction in response to a change in the position of the tape in the cross direction while the cutter is cutting the tape.

2. A box opening device for opening a box by cutting a tape attached along a periphery of a flap that closes an opening of the box, comprising: a position detection unit that detects a position of the tape in a direction intersecting with the opening surface of the box to which the tape is attached; a detection unit that detects the opening surface from a position away from the box and acquires detection information necessary to identify a cutting path of the tape; a cutter that moves relative to the box to cut the tape; a control unit that identifies a cutting path of the tape based on the detection information and cuts the tape by controlling the position of the cutter along the identified cutting path, The position detection unit detects a plurality of positions of the tape in the cross direction along the cutting path, The control unit controls the inclination angle of the cutter relative to the surface of the tape so that it falls within an allowable range in accordance with a change in the position of the tape in the cross direction during the process of the cutter cutting the tape.

3. 3. The box opening device according to claim 1, wherein the position detection unit detects a plurality of positions of the tape in the intersecting direction along the cutting path during a process in which the cutter cuts the tape along the cutting path.

4. 4. The box opening device according to claim 1, wherein the position detection unit is a non-contact type position detection unit that detects the position of the tape in the cross direction in a non-contact manner.

5. The box opening device described in any one of claims 1 to 4, characterized in that the detection unit includes a second position detection unit that detects the position of the tape on the opening surface in the intersecting direction, and an imaging unit that detects an image including the outline of the opening surface by imaging the opening surface.

6. The imaging unit is fixed at a predetermined height position capable of imaging the opening surface of the box, an articulated robot having an arm with the cutter attached to a tip end thereof and controlled by the control unit; 6. The box opening device according to claim 5, further comprising: a lifting mechanism that raises or lowers the box until the opening surface of the box reaches a height position at which the opening surface becomes a focus of the imaging unit.

7. A conveying mechanism is further provided for conveying the box horizontally along the longitudinal direction of the tape, The control unit, when a portion of the tape is within the movable area of ​​the cutter and another portion of the tape is not within the movable area, cuts the portion of the tape by the cutter, and cuts the other portion of the tape by the cutter accompanied by a transporting operation of transporting the box horizontally until the other portion of the tape is positioned at a cutting position within the movable area. The box opening device of any one of claims 1 to 6, characterized in that

8. A method for opening a box, comprising the steps of: cutting a tape attached along a periphery of a flap that closes an opening of the box to open the box; a position detection step of detecting a position of the tape in a transverse direction intersecting with the taped opening surface of the box; a detection step of detecting the opening surface of the box and acquiring detection information necessary to identify a cutting path of the tape; a control step of identifying a cutting path of the tape from the detection information and cutting the tape by controlling the position of a cutter along the identified cutting path, In the position detection step, a plurality of positions of the tape in the cross direction are detected along the cutting path, The method for opening a box, wherein in the control step, the position of the cutter in the cross direction is controlled in response to a change in the position of the tape in the cross direction while the cutter is cutting the tape.

Images