JP2019005835A - Workpiece transfer method - Google Patents

Abstract

To stably hold and smoothly transfer a workpiece in transferring the workpiece by using a robot between conveyance devices on different lines, and prevents interference between a hand part of the robot and the conveyance device.SOLUTION: A workpiece W is transferred from a hanger carrier 102 on a carrying-in line L2 to a tool 40 mounted on a hand part 22 of a carrying-in robot 11. The tool 40 and the workpiece W are conveyed by the carrying-in robot 11 to a carriage 201 of an intermediate line L1, and the tool 40 is removed from the hand part 22 of the carrying-in robot 11 to integrally transfer the tool 40 and the workpiece W to the carriage 201. By mounting the hand part 22 of the carrying-out robot 12 to the tool 40 loaded on the carriage 201, the tool 40 and the workpiece W are integrally held by the carrying-out robot 12. The tool 40 and the workpiece W are conveyed by the carrying-out robot 12 to the hanger carrier 102 of a carrying-out line L3, and the workpiece W is transferred to the hanger carrier 102 of the carrying-out line L3 from the tool 40 mounted on the hand part 22 of the carrying-out robot 12.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a workpiece transfer method in which a workpiece is transferred from a carry-in line to an intermediate line, subjected to a predetermined process, and then transferred from the intermediate line to a carry-out line.

  For example, in an automobile assembly process, a door is removed from a vehicle body that has undergone a painting process, and various parts are assembled to each other while the vehicle body and the door are conveyed by different paths, and then the door is attached to the vehicle body again. The door removed from the vehicle body is transported by a hanger conveyor, transferred to the equipment line, assembled with various components, and then transferred again to the hanger conveyor and transported to the mounting area on the vehicle body.

  In the assembly equipment as described above, it is necessary to transfer the door removed from the vehicle body to a door conveyance line (hanger conveyor) or a door fitting line. For example, in Patent Document 1 below, a door removed from a vehicle body is transferred to a hanger conveyor by a robot arm. Specifically, the robot arm is transferred to the hanger carrier while the lower part of the door is held by the support part of the robot arm.

JP 2007-145561 A

  However, as described above, in the state where only the lower part of the workpiece is supported by the robot arm, the support of the workpiece becomes unstable, and therefore there is a possibility that the workpiece cannot be smoothly transferred to the hanger carrier.

  For example, if the robot arm holds not only the lower part of the work but also the intermediate part in the vertical direction of the work, the work can be stably held. However, in this case, since it is necessary to provide the holding part for holding the lower part of the work and the holding part for holding the intermediate part in the vertical direction of the work in the hand part of the robot arm, the hand part is enlarged. For this reason, when the workpiece is transferred to another transfer device, the hand part of the robot arm may interfere with the other transfer device, which may hinder the transfer operation.

  Therefore, in the present invention, when transferring a workpiece using a robot between transfer devices of different lines, the workpiece is stably held and the transfer is performed smoothly. The aim is to avoid interference.

  In order to solve the above-mentioned problems, the present invention provides a workpiece transfer method for transferring a workpiece between a hanger conveyor and another transfer device by a transfer robot, wherein the workpiece is transferred to a hand portion of the transfer robot. A step of transferring a workpiece between the jig and the hanger conveyor in a state where a tool is attached; and a state where the jig and the workpiece are mounted on the transfer device, Provided is a workpiece transfer method including a step of integrally transferring the jig and the workpiece between the transfer robot and the transfer device by attaching and detaching the jig.

  Thus, in the workpiece conveyance method of the present invention, the workpiece is transferred between the hanger conveyor and the transfer robot with the jig attached to the hand portion of the transfer robot. In this case, since the workpiece is mounted on a jig, the workpiece can be stably held by providing a holding portion for holding a desired part of the workpiece on the jig.

  On the other hand, the transfer of the workpiece between the other transfer device and the transfer robot is a state in which the jig and the workpiece mounted thereon are integrated by detaching the hand portion of the transfer robot and the jig. To do. In this case, since it is not necessary to separate the jig from the workpiece, it is possible to avoid a situation in which the jig interferes with other transfer devices even when the jig is enlarged by providing the holding portion.

  The workpiece transfer method described above includes transferring a workpiece from a transfer line transfer device (for example, a hanger carrier) to an intermediate line transfer device and performing a predetermined process, and then transferring the intermediate line transfer device to a transfer line transfer device ( For example, it can be applied when transferring a work to a hanger carrier. In this case, the step of transferring the workpiece from the carry-in line transfer device to the intermediate line transfer device is a step of transferring the work from the carry-in line transfer device to a jig attached to the hand portion of the carry-in robot; The jig and workpiece are transported to the intermediate line transport device by the carry-in robot, and the jig and workpiece are integrated with the intermediate line transport device by removing the jig from the hand portion of the carry-in robot. And a step of transferring to the device. On the other hand, the step of transferring the workpiece from the intermediate line transfer device to the carry out line transfer device is performed by attaching the hand portion of the carry robot to the jig mounted on the intermediate line transfer device. A step of integrally holding the jig and the workpiece, and the unloading robot transports the jig and the workpiece to a conveying device of the unloading line, and the unloading line from the jig attached to the hand portion of the unloading robot. And a step of transferring the workpiece to the transfer device.

  In the above workpiece transfer method, after the workpiece is transferred from the transfer device of the intermediate line to the transfer device of the carry-out line by the carry-out robot, the jig is removed from the hand portion of the carry-out robot and placed on the temporary stand. It is preferable to attach the hand portion of the carry-in robot to the mounted jig and transfer the workpiece from the carry-in line transfer device to the intermediate line transfer device. As a result, while performing the process of placing the jig held by the carry-out robot on the temporary placement table and the process of holding the jig of the temporary placement table by the carry-in robot, the intermediate line transfer device is moved from the front of the carry-out robot. Since it can be transported to the front of the loading robot, the transfer cycle time can be shortened.

  As described above, in the workpiece transfer method of the present invention, the workpiece can be transferred stably between transfer devices of different lines by using a jig attached to the hand portion of the transfer robot. The transfer can be carried out smoothly by holding it. In addition, by transferring the workpiece between the transfer robot and the transfer device in the intermediate line in a state where the jig and the workpiece are integrated, a situation where the jig and the transfer device interfere with each other is avoided. Can do.

It is a top view of the assembly equipment of the door of a motor vehicle. It is a side view of the said assembly equipment. (A) is a side view of a hanger, (B) is the front view. (A) is a side view of the jig, (B) is a front view thereof, and (C) is a plan view thereof. (A) is a top view of the hand part of a transfer robot, (B) is the same side view. It is a front view which shows a mode that the jig | tool hold | maintained with the transfer robot is accessed to a workpiece | work (hanger and door) from the downward direction. It is a front view which shows a mode that a workpiece | work is hold | maintained with the jig | tool hold | maintained with the transfer robot. It is a table | surface which shows the cycle time of each process of transfer. It is a side view of the assembly equipment which concerns on other embodiment. 10 is a table showing cycle times of each process of transfer in the assembly facility of FIG. 9.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an automobile door assembly facility. This assembly facility includes a door fitting line L1 as an intermediate line for assembling various parts to the door, a loading line L2 for carrying the door before the various parts are attached to the door fitting line L1, and a door to which the various parts are attached. And an unloading line L3 for unloading from the door fitting line L1. In the following description, the transport direction of each line is referred to as “transport direction”, and the horizontal direction orthogonal to the transport direction is referred to as “width direction”.

  The door equipping line L1 has a transport device that transports the door, and an operator assembles various parts to the door transported by the transport device. The conveyance device has a placement surface on which a door (work) is placed. In the present embodiment, a plurality of carriages 201 are provided as the transfer device. The carriage 201 is, for example, an automatic guided vehicle (AGV), and travels in a rope shape along a magnetic tape attached to a floor surface. In addition, the conveying apparatus of the door fitting line L1 is not limited to the carriage 201 (AGV), and may be a floor conveyor or the like.

  In this embodiment, a hanger conveyor is provided in the carry-in line L2 and the carry-out line L3. In the illustrated example, a common hanger conveyor 100 is provided in the carry-in line L2 and the carry-out line L3. That is, the door before assembling the parts is transferred from the hanger conveyor 100 to the door fitting line L1, and various parts are assembled to the door by the door fitting line L1, and then the door is assembled from the door fitting line L1 to the hanger. Transfer to the conveyor 100. In addition, you may comprise the carrying-in line L2 and the carrying-out line L3 with a separate hanger conveyor.

  As shown in FIG. 2, the hanger conveyor 100 includes a rail 101 and a hanger carrier 102 as a transport device that travels along the rail. The hanger carrier 102 includes a hook 102a. By hooking the upper portion of the hanger W1 on the hook 102a, the hanger W1 and a door W2 mounted thereon (hereinafter, collectively referred to as a workpiece W) are suspended and held. The

  As shown in FIGS. 3A and 3B, the hanger W1 includes an upper frame W11 that is locked to the hook 102a of the hanger carrier 102, a pair of lower frames W12 that are spaced apart in the width direction, A pair of connection frames W13 that connect the frame W11 and the lower frame W12, and an intermediate frame W14 that connects the upper and lower intermediate portions of the pair of connection frames W13 in the horizontal direction are provided. A support portion W15 that supports the lower portion of the door W2 is attached to the lower frame W12. In the present embodiment, as shown in FIG. 3B, support portions W15 are provided on both sides in the width direction of the lower frame W12, and the lower portions of the doors W2 are placed on the support portions W15, respectively. The support portion W15 is provided with a V-groove on the upper surface, whereby the lower portion of the door W2 is positioned in the width direction. The middle part of the door W2 in the vertical direction is held on the hanger W1 by holding means (not shown).

  The above door assembly facility is provided with a transfer robot for transferring the workpiece W between the hanger conveyor 100 and the door fitting line L1. In this embodiment, as shown in FIG. 1, the loading robot 11 that transfers the workpiece W from the hanger conveyor 100 (loading line L2) to the door fitting line L1, and the door loading line L1 to the hanger conveyor (unloading line L3). An unloading robot 12 for transferring the workpiece W is provided. A temporary placement table 30 is provided between the carry-in robot 11 and the carry-out robot 12 for placing the jig 40 used when the workpiece W is transferred.

  As shown in FIGS. 4A to 4C, the jig 40 includes a rectangular base 41, a column 42 extending upward from the base 41, and a holding portion 43 provided on the top of the column. The support columns 42 are provided at two locations separated in the transport direction. The holding portion 43 includes a concave portion 43a provided at the center in the width direction, a pair of inner guide surfaces 43b that are continuous with the upper end of the concave portion 43a and are inclined outward in the width direction as going upward, and on the outer side in the width direction of the holding portion 43. A pair of outer guide surfaces 43c provided on the side surfaces and inclined inward in the width direction as going upward. The base 41 is provided with a fixing hole 44 penetrating in the vertical direction. A support portion 45 that supports the hanger W <b> 1 from below is provided on the upper surface of the base 41.

  In the present embodiment, the carry-in robot 11 and the carry-out robot 12 have the same configuration, and both have an articulated arm 21 and a hand portion 22 provided at the tip thereof (see FIG. 2). The hand unit 22 includes a support unit that supports the jig 40 from below, a positioning unit that positions the jig 40 in the width direction, and a fixing unit that fixes the jig 40 to the hand unit 22. In this embodiment, as shown in FIGS. 5A and 5B, a ball bearing 22a that supports the base 41 of the jig 40 in a state of being freely movable in the horizontal direction is provided as a support portion. As the positioning portion, for example, a fixed contact portion 22b that comes into contact with the base 41 of the jig 40 from one side in the width direction and a movable contact portion 22c that comes into contact with the base 41 of the jig 40 from the other side in the width direction are provided. It is done. The movable contact portion 22c is driven in the width direction by a cylinder 22d as a drive portion. As the fixing means, for example, a locking member 22e and a cylinder 22f as a driving unit for driving are provided. The cylinder 22f rotates the locking member 22e by 90 ° and drives it in the vertical direction (direction orthogonal to the base 41).

  Hereinafter, a method for transporting the workpiece W in the door assembly facility will be described.

  First, the jig 40 placed on the temporary table 30 is attached to the hand portion 22 of the carry-in robot 11. As shown in FIG. 2, since the concave portion 31 is formed in the intermediate portion in the transport direction of the temporary table 30, a space G <b> 1 is provided below the base 41 of the jig 40 placed on the temporary table 30. In this space G1, the hand unit 22 of the carry-in robot 11 is arranged, and the hand unit 22 is raised to lift the jig 40. Thereby, as shown in FIGS. 5A and 5B, the base 41 of the jig 40 is supported from below by the ball bearing 22a of the hand portion 22. At this time, the locking member 22e of the hand portion 22 is inserted into the fixing hole 44 of the base 41 of the jig 40, and the locking member 22e is disposed above the base 41. In this state, by pulling the cylinder 22d, the movable contact portion 22c and the fixed contact portion 22b hold the base 41 of the jig 40 from both sides in the width direction, and the jig 40 is moved in the width direction with respect to the hand portion 22. Position with. Thereafter, the locking member 22e is rotated 90 ° by the cylinder 22f and {refer to the dotted line in FIG. 5A}, and the locking member 22e is pulled downward, thereby pressing the base 41 of the jig 40 from above and the hand. It fixes to the part 22.

  Next, the jig 40 attached to the hand portion 22 of the carry-in robot 11 is moved to the workpiece W conveyed by the hanger conveyor 100, and the workpiece W is transferred from the hanger carrier 102 to the jig 40 (FIGS. 1 and FIG. 1). 2 arrow A1). Specifically, as shown in FIG. 6, the jig 40 attached to the hand unit 22 is raised from below the workpiece W conveyed by the hanger conveyor 100. At this time, the outer guide surface 43c provided on the holding portion 43 of the jig 40 comes into contact with the pair of lower frames W12 of the hanger W1 from the inside, so that the hanger W1 is positioned in the width direction with respect to the jig 40. The Thereafter, by further raising the jig 40, as shown in FIG. 7, the intermediate frame W14 of the hanger W1 is fitted into the concave portion 43a of the holding part 43 of the jig 40, and the support part 45 of the jig 40 is fitted. However, the lower frame W12 of the hanger W1 is supported from below. In this way, not only the lower part of the work W (lower frame W12) is held, but also the work W is stabilized by holding the vertical intermediate part (intermediate frame W14) of the work W in the width direction with the jig 40. Can be held in a state. In this state, the hand part 22, the jig 40, and the work W are raised integrally, and the work W is removed from the hook 102a (see FIG. 3) of the hanger carrier 102. Thus, the workpiece W is transferred from the hanger conveyor 100 to the carry-in robot 11.

  Next, the jig 40 and the workpiece W held by the hand unit 22 of the carry-in robot 11 are transferred to the carriage 201 on the door fitting line L1 (see arrow A2 in FIGS. 1 and 2). The carriage 201 has a recess 201a at the intermediate portion in the transport direction. Therefore, when the work W is placed on the carriage 201, a space G2 is formed below the jig 40, and the hand portion 22 of the loading robot 11 is accommodated in the space G2 (see FIG. 2). Thereafter, the movable contact portion 22c is retracted by the cylinder 22d of the hand portion 22, and the locking member 22e is lifted and rotated by 90 ° by the cylinder 22f (see the solid line in FIG. 5A). The fixation with the tool 40 is released. In this state, the hand part 22 is lowered and separated from the jig 40. As described above, the workpiece W is transferred from the loading robot 11 to the carriage 201 of the door fitting line L1.

  Next, in the door fitting line L1, various parts are assembled to the door W2 while the work 201 is conveyed in a loop by the carriage 201. Then, the door W2 on which the predetermined parts are assembled is held by the carry-out robot 12 while being integrated with the hanger W1 and the jig 40. Specifically, the hand unit 22 of the unloading robot 12 is disposed in the space G2 below the jig 40 placed on the carriage 201 and is raised, so that the hand unit 22 moves the jig 40 and the workpiece W. Lift up slightly. In this state, the workpiece W is positioned in the width direction on the hand portion 22 by sandwiching the base 41 of the jig 40 from both sides in the width direction by the movable contact portion 22c and the fixed contact portion 22b of the hand portion 22. At the same time, the jig 40 is attached to the hand portion 22 by rotating the locking member 22e by 90 ° and then pulling it downward. In addition, since the attachment method of the hand part 22 and the jig | tool 40 is the same as the procedure at the time of hold | maintaining the jig | tool 40 with said carrying-in robot 11, detailed description is abbreviate | omitted.

  Next, the jig 40 and the workpiece W held by the hand unit 22 of the carry-out robot 12 are transferred to the hanger carrier 102 of the hanger conveyor 100 (see arrow B1 in FIGS. 1 and 2). Specifically, the upper frame W11 of the hanger W1 is hooked on the hook 102a of the hanger carrier 102. Thereafter, the jig 40 attached to the hand portion 22 is lowered to separate the jig 40 from the workpiece W.

  Next, the jig 40 attached to the hand portion 22 of the carry-out robot 12 is placed on the temporary placement table 30 (see arrow B2 in FIGS. 1 and 2). Specifically, as shown in FIG. 2, the base 41 of the jig 40 is placed on the temporary table 30. At this time, the hand portion 22 that holds the jig 40 is disposed in a space G <b> 1 provided below the base 41. Thereafter, the movable contact portion 22c is retracted by the cylinder 22d of the hand portion 22, and the locking member 22e is lifted and rotated by 90 ° by the cylinder 22f (see the solid line in FIG. 5A). The fixation with the tool 40 is released. In this state, the hand part 22 is lowered and separated from the jig 40. Thereafter, the jig 40 placed on the temporary placement table 30 is again held by the carry-in robot 11 and used to transfer the workpiece W from the hanger conveyor 100 to the door fitting line L1. By repeating the above, the assembly process of the door W2 is sequentially performed.

  As described above, when the work W is held by the transfer robot (the carry-in robot 11 and the carry-out robot 12) and is transported between the hanger conveyor 100 and the carriage 201, the work W is held using the jig 40. Thus, not only the lower portion of the workpiece W is supported, but also the intermediate portion in the vertical direction of the workpiece W is positioned in the width direction by the holding portion 43, so that the workpiece W can be stably held. In particular, when the workpiece W is transferred from the carriage 201 to the hanger conveyor 100 by the unloading robot 12, the position of the upper end of the workpiece W (the upper frame W11 of the hanger W1) is held by holding the workpiece W at a plurality of locations in the vertical direction. Therefore, the upper frame W11 of the hanger W1 can be smoothly hooked on the hook 102a of the hanger carrier 102.

  For example, when the jig 40 having the holding unit 43 and the support column 42 is provided integrally with the hand unit 22 of the transfer robot, the hand unit 22 becomes large. For this reason, when the work W is mounted on the carriage 201 or when the work W is picked up from the carriage 201, the support column 42 provided on the hand unit 22 may interfere with the work W, the carriage 201, or the like. Therefore, in the present invention, as described above, the jig 40 having the holding portion 43 and the support column 42 and the hand portion 22 of the transfer robot are attached to and detached from the transfer robot and the carriage 201. 40 and the workpiece W were transferred in an integrated state. In this case, since it is not necessary to separate the jig 40 having the support column 42 and the holding portion 43 from the work W, the handling of the hand portion 22 is facilitated, and the transfer operation can be performed smoothly.

  As described above, the jig 40 removed from the carry-out robot 12 is held and used by the carry-in robot 11. For this reason, when the carry-out robot 12 and the carry-in robot 11 are separated from each other, it is necessary to carry the jig 40 removed from the carry-out robot 12 to the carry-in robot 11. In the present embodiment, since the loading robot 11 and the unloading robot 12 can be arranged close to each other by arranging the door equipping line L1 in a loop shape, the jig 40 is transferred from the unloading robot 12 to the loading robot 11. Therefore, it is possible to reduce the number of man-hours, equipment space, and the total number of jigs 40.

  In the work transfer method described above, after the work W of the carriage 201 is lifted by the carry-out robot 12, the carriage 201 is moved to the front of the carry-in robot 11 (see arrow C in FIG. 2). In this case, as shown in FIG. 8, a step of placing the jig 40 on the temporary placement table 30 by the unloading robot 12 (see B2), or a hanger conveyor holding the jig 40 of the temporary placement table 30 by the loading robot 11. During the process of receiving 100 workpieces W (see A1), the carriage 201 can be moved from the front of the carry-out robot 12 to the front of the carry-in robot 11.

  On the other hand, in the embodiment shown in FIG. 9, after the workpiece W is transferred from the carriage to the hanger conveyor 100 by the carry-out robot 12 (see arrow B1 in FIG. 9), the jig 40 is moved from the hanger conveyor 100 by the carry-out robot 12. Return to cart 201 (see arrow B2 '). Then, the carriage 201 on which the jig 40 is mounted travels to the front of the carry-in robot 11 (see the arrow C ′), holds the jig 40 on the carriage 201 by the carry-in robot 11 and receives the workpiece W of the hanger conveyor 100. (Refer to the arrow A1 ′) The work W is transferred from the hanger conveyor 100 to the carriage 201 by the loading robot 11 (see the arrow A2). As described above, the jig 40 is not placed on the temporary table 30 (see FIG. 2), but is returned to the carriage 201, so that the temporary table 30 becomes unnecessary, and the equipment space can be reduced.

  However, in this case, as shown in FIG. 10, while the jig 40 is being transported by the carriage 201, the process B <b> 2 for returning the jig 40 to the carriage 201 by the carry-out robot 12 or the carriage 201 on the carriage 201. Since the process A1 for holding the jig cannot be performed, the cycle time becomes longer than that in the embodiment shown in FIG. Therefore, when the cycle time is important, a temporary table 30 for placing the jig 40 is provided as shown in FIG. 2, and when the facility space is important, the temporary table 30 is omitted as shown in FIG. What is necessary is just to convey the jig | tool 40 with the trolley | bogie 201. FIG.

  The present invention is not limited to the above embodiment. Hereinafter, although other embodiment of this invention is described, description is abbreviate | omitted about the point similar to said embodiment.

  In the above-described embodiment, the case where two transfer robots (the carry-in robot 11 and the carry-out robot 12) are used has been described. However, the present invention is not limited to this, and the work W is carried in and carried out by one transfer robot. May be. In this case, after the workpiece W that has passed through the door equipping line L1 is transferred from the carriage 201 to the hanger conveyor 100, the next workpiece W that is carried into the door equipping line L1 while holding the jig 40 is transferred from the hanger conveyor 100 to the carriage 201. Cycle time can be further shortened.

  Further, in the above-described embodiment, the present invention is applied to both the loading of the work W from the hanger conveyor 100 to the carriage 201 of the door fitting line L1 and the unloading of the workpiece W of the hanger conveyor 100 from the carriage 201 of the door fitting line L1. However, the present invention is not limited to this, and the present invention is applied to only one of the loading of the workpiece W into the door fitting line L1 and the unloading of the workpiece W from the door fitting line L1, and the other Other transfer means (for example, transfer by an operator, transfer by a drop lift, etc.) may be applied.

  In addition, the intermediate line is not limited to the door equipping line L1, but may be any line that performs some process on the loaded workpiece.

11 Carry-in robot (transfer robot)
12 Unloading robot (transfer robot)
21 Articulated arm 22 Hand part 30 Temporary table 40 Jig 100 Hanger conveyor 101 Rail 102 Hanger carrier (conveyance device)
201 trolley (conveyor)
L1 door fitting line (intermediate line)
L2 Carry-in line L3 Carry-out line W Work W1 Hanger W2 Door

Claims (2)

This is a workpiece transfer method in which a workpiece is transferred from the transfer device of the carry-in line to the transfer device of the intermediate line and subjected to a predetermined process, and then the workpiece is transferred from the transfer device of the intermediate line to the transfer device of the carry-out line. And
A step of transferring a workpiece from a transfer device of the carry-in line to a jig attached to a hand portion of the carry-in robot; and the carry-in robot conveys the jig and the workpiece to the transfer device of the intermediate line; Removing the jig from the hand part, and transferring the jig and the workpiece integrally to the intermediate line transfer device;
A step of holding the jig and the workpiece integrally with the carry-out robot by attaching a hand portion of the carry-out robot to the jig mounted on the transfer device of the intermediate line, and the jig and A workpiece transfer method comprising: transferring the workpiece to the transfer device of the carry-out line, and transferring the workpiece from the jig attached to the hand unit of the carry-out robot to the transfer device of the carry-out line.   After the workpiece is transferred from the transfer device of the intermediate line to the transfer device of the carry-out line by the carry-out robot, the jig is removed from the hand portion of the carry-out robot and placed on the temporary table, and placed on the temporary table. The work transfer method according to claim 1, wherein a hand unit of the carry-in robot is attached to the placed jig, and the work is transferred from the transfer device of the carry-in line to the transfer device of the intermediate line.

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