JP2007061947A - Stock device of carrying object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a convenient stock device capable of quickly and concurrently performing carrying-in-and-out of a carrying object. <P>SOLUTION: The stock device is disposed in the processing line and temporarily stocks the carrying object conveyed in the line. The stock device is equipped with a rack 4 having horizontally disposed shelves 5 with a plurality of stages, a carrying-in conveyor 6 which is liftably installed at the further upstream side in the conveyance direction of the carrying object than the rack 4 so as to carry in the carrying object to the respective shelves 5, and a carrying-out conveyor 7 which is liftably installed at the further downstream side in the conveyance direction of the carrying object than the rack 4 so as to carry out the carrying object from the respective shelves 5 of the rack 4. While the carrying-in conveyor 6 mounting the carrying object is moved to the height position of the shelves 5 where the carrying object is carried in, the carrying-out conveyor 7 is moved to the height position of the shelves 5 where the carrying object to be carried out is mounted. The respective shelves 5 of the rack 4 are composed of the conveyor which is driven when carrying-in the carrying object by the carrying-in conveyor 6 and carrying-out the carrying object by the carrying-out conveyor 7. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a stock apparatus that is interposed in a process line for manufacturing a liquid crystal panel or the like and temporarily stores a conveyed product.

  Generally, as a means of mass-producing products such as liquid crystal panels, a process line of a predetermined length is constructed in which various processes such as molding and assembly are continuously performed by connecting various equipment machines. When a failure occurs in an equipment machine, the transported material cannot be supplied to the equipment machine, and the supply of the transported material to the subsequent equipment machine is also interrupted. As a result, the entire process must be stopped.

  Therefore, in order to avoid the need to stop the entire process even if a failure occurs in a part of the equipment machine, a stock device capable of temporarily storing work in progress as a transported product is provided in the middle of the process line. It is generally done widely.

  As such a stock apparatus, the elevating frame having a plurality of shelves that are lined up and down and projecting inward from the left and right, and projecting from the left and right side inward in the flow direction of the flat plate (conveyed object). A plurality of conveyor shafts, each having a roller conveyor provided with a conveying roller for supporting a flat plate, and a flat plate supporting position in which the roller conveyor protrudes inward and a flat plate non-supporting position in which the roller conveyor is drawn outward. The thing of the structure which can be moved to right and left simultaneously between is known (for example, patent document 1).

JP 2000-263369 A

  However, according to the stock device of Patent Document 1, since the lifting frame having a plurality of shelves is configured to move up and down, the load on the lifting operation becomes large in the state where each shelf is full of transported goods, For this reason, an actuator that generates a large driving force is required, and the entire apparatus becomes large. In addition, there is a drawback in that much energy is consumed when the apparatus is operated.

  In addition, since loading / unloading of conveyed items to / from each shelf is performed by roller conveyors provided on the left and right sides of the lifting frame, the loading operation and the unloading operation cannot be performed in parallel. Since the elevating operation of the elevating frame and the right and left movement of the roller conveyor are performed, it is difficult to adjust the operation timing of the elevating frame, and it takes time to carry in and out the conveyed product with respect to one shelf.

  In addition to the space between the upper and lower shelves, the space between the roller conveyor and the shelves and the space between the roller conveyor and the shelves are required for the transfer of goods. Is likely to grow, and if you try to reduce its height, you will not be able to install many shelves.

  In addition, since roller conveyors are provided on the left and right sides of the lifting frame, even if the lifting frame is raised to the maximum extent, an operator cannot dive under it. Therefore, it is not possible to cross a process line that is connected in series in a state where many equipment machines are close to each other, and it is necessary to bypass both ends in the longitudinal direction of the line to go to the opposite side, so it is not possible to quickly cope with an emergency situation. .

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a simple stock apparatus that can quickly carry in and out a conveyed product in parallel.

  In order to achieve the above-mentioned object, the present invention provides a stock apparatus for temporarily storing a transported material that is interposed in a process line and flows to the line, a rack having a plurality of shelves arranged horizontally, and each of the racks. A carry-in conveyor provided so as to be able to move up and down in the conveyance direction of the conveyed product relative to the rack in order to carry the conveyed product to the shelf, a first raising / lowering means for raising and lowering the carry-in conveyor, and conveying from each shelf of the rack An unloading conveyor provided so as to be able to move up and down in the conveying direction of the conveyed object from the rack in order to unload the object, and second elevating means for elevating and lowering the unloading conveyor, The carry conveyor is moved to the height position of the shelf on which the carry object to be carried is placed, while the carry conveyor is moved to the height position of the shelf on which the carry article to be carried is placed. Characterized in that it consists conveyors traveling driven during unloading of conveyed by the discharge conveyor and when loading the carried object by conveyor.

  In addition, a control means for controlling the driving of the first lifting means and the second lifting means is provided, and the control means includes an address of a shelf for carrying a conveyed product as storage shelf designation data for controlling the first lifting means. A storage unit for storing an address of a shelf for carrying a transported object as delivery shelf designation data for controlling the second elevating means, and an input unit for enabling setting change of the delivery shelf designation data stored in the storage unit; It is provided.

  Further, when at least one of the carry-in conveyor and the carry-out conveyor exceeds a predetermined height, the operator can pass in the transverse direction of the process line with the lower region on at least one side as a passage. .

  According to the stock apparatus according to the present invention, the carry-in conveyor and the carry-out conveyor can be moved up and down on the upstream side and the downstream side in the conveyance direction of the conveyed product with a rack having a plurality of shelves composed of conveyors that can be driven. For this reason, the conveyed product can be carried out from the arbitrary shelf by the carry-out conveyor in parallel with the conveyed product being carried into the arbitrary shelf by raising and lowering the carry-in conveyor.

  In addition, since the rack is not raised and lowered when carrying in / out of the conveyed product, the carry-in conveyor and the carry-out conveyor are raised and lowered, so that the carry-in and carry-out conveyors are moved up and down by using a small actuator as the raising and lowering means. Can be carried out easily and quickly, and the carry-in conveyor and the carry-out conveyor move up and down, so that depending on the configuration of the process line, the stand-by position of the carry-in conveyor is located upstream of the equipment machine. The standby position of the carry-out conveyor can be set to the conveyance height of the conveyed product by the equipment machine located downstream thereof.

  In addition, each shelf of the rack consists of a conveyor that is driven to move in and out of the transported object, so a roller conveyor is inserted between the shelves. Many shelves can be provided while setting the rack height low and the rack height is set low, and even if the racks are full of transported goods, the racks are not raised or lowered, so that energy consumption is reduced when operating the equipment. Less running costs can be reduced.

  In addition, control means for controlling the driving of the first and second lifting / lowering means is provided, and the control means includes an address of a shelf for carrying a conveyed product as storage shelf designation data for controlling the first lifting / lowering means, and the first 2 Since a storage unit is provided for storing the address of the shelf for carrying out the transported goods as the output shelf designation data for controlling the lifting means, it is possible to automatically carry in / out the transported goods to and from each shelf, Since the control means has an input unit that enables the setting change of the outgoing shelf designation data stored in the storage unit, it is preferentially carried out from the shelf loaded with defective products and taken out of the line. Or keep it on top.

  In addition, when at least one of the carry-in conveyor and the carry-out conveyor exceeds a predetermined height, the operator can pass in the transverse direction of the process line using the lower area on at least one side as a passage. Even a long process line with equipment machines in close proximity can go to the opposite side without bypassing both sides in the longitudinal direction or installing stairs across the line.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic side view showing a stock apparatus for a conveyed product according to the present invention, and FIG. 2 is a schematic plan view of the apparatus. In FIGS. 1 and 2, reference numeral 1 denotes a rectangular frame formed including support columns 2 standing at a predetermined interval. A level adjusting telescopic leg 3 and a caster (not shown) are provided at the lower end of the frame 1. Provided. The frame 1 can be fixed at a fixed position in a state where the caster is lifted by an expansion / contraction operation of the expansion / contraction leg 3.

  Reference numeral 4 denotes a rack fixed to the center portion of the frame 1, and a plurality of (5 in the illustrated example) shelves 5 are horizontally provided in the rack 4 at regular intervals in the vertical direction. Each of the shelves 5 is composed of a conveyor (in this example, a roller conveyor) that can be individually driven, and a predetermined conveyed product is loaded thereon.

  6 is a carry-in conveyor that is provided adjacent to the rack and upstream of the conveyed product (left side in FIG. 1), and 7 is adjacent to the rack and downstream of the conveyed product in the conveyance direction (of FIG. 1). The carry-in conveyor 6 and the carry-out conveyor 7 can be moved up and down corresponding to each shelf 5 of the rack 4.

  And according to the stock apparatus which concerns on this invention, when a conveyed product is transferred from the upstream with respect to the carrying-in conveyor 6, the carrying-in conveyor 6 puts the conveyed product on the shelf 5 with which it was scheduled to carry in After moving to the height position, the carry-in conveyor 6 and the shelf 5 corresponding to the carry-in conveyor 6 are driven to carry the conveyed product from the carry-in conveyor 6 to the planned shelf 5, while the conveyed product is loaded. When unloading a conveyed product from the shelf 5, the unloading conveyor 7 is moved to a predetermined height position of the shelf 5, and then the unloading conveyor 7 and the corresponding shelf 5 are driven to move from the shelf to the unloading conveyor 7. A conveyed product is carried out on top.

  The carry-in conveyor 6 returns to the initial position (for example, the position shown in FIG. 1) after carrying the conveyed product and waits to receive the next conveyed product from the upstream side, and the carry-out conveyor 7 is initialized after carrying the conveyed product. After returning to the position (for example, the position shown in FIG. 1), the traveling drive is performed again, and the conveyed product received from the shelf 5 is delivered to the downstream side.

  Here, the initial standby position (height position at the time of standby) of the carry-in conveyor 6 and the carry-out conveyor 7 can be arbitrarily set according to the conveyance height of the conveyed product by the process line. In particular, the standby position of the carry-out conveyor 6 is set so as to correspond to the conveyance height of the conveyed product by the preceding-stage equipment machine located upstream thereof, while the standby position of the carry-out conveyor 7 is the subsequent equipment machine located downstream thereof. It is set so as to correspond to the transport height of the transported object. For this reason, regardless of the position intervening in the process line and the organization of the process line, the transported object is transferred from the preceding equipment machine to the carry-in conveyor 6 or transferred from the carry-out conveyor 7 to the subsequent equipment machine. Can be.

  FIG. 3 is a schematic plan view showing an arrangement portion of the carry-in conveyor, and FIG. 4 is a schematic front view of the arrangement portion of the carry-in conveyor as viewed from the upstream side in the conveyance direction of the conveyed product. 3 and 4, 10 is an actuator (for example, a servo motor) used for raising and lowering the carry-in conveyor, 11 is a guide shaft for guiding the lift of the carry-in conveyor, and 12 is carrying in the rotational movement of the actuator 10 along the guide shaft 11. These are transmission systems that convert the linear motion of the conveyor, and they constitute first lifting means for raising and lowering the carry-in conveyor 6.

  Of these, two guide shafts 11 are fixed upright on both the left and right sides of the carry-in conveyor 6 along the support pillars of the frame, and are fitted to the both sides of the carry-in conveyor 6 slidably with respect to the guide shafts 11. The slide 13 is fixed.

  On the other hand, the transmission system 12 includes a pair of left and right rotating shafts 14 provided at the lower portion of the frame, a lower pulley 15 fixed to both ends of the rotating shaft 14, and a frame pulley corresponding to the lower pulley 15. The upper pulley 16 is rotatably provided on the upper portion, and the pulleys 15 and 16 are rotationally driven simultaneously in the same direction by driving of the actuator 10.

  Here, pulleys 18 and 19 around which a belt 17 is wound are fixed to one rotating shaft 14 and the output shaft of the actuator 10, and pulleys 21 around which a belt 20 is wound are fixed to the rotating shafts 14 on both sides. Also, belts 22 are wound around the four sets of lower pulley 15 and upper pulley 16, and the portions of the belts 22 are locked to the carry-in conveyor 6.

  3 and 4, reference numeral 23 denotes a holder for locking the belt 22, and the holder 23 is fixed to the slide 13 and is configured to hold the belt 22 by a part thereof.

  Thus, when the actuator 10 is driven to rotate in the forward and reverse directions, the belt 22 wound between the lower pulley 15 and the upper pulley 16 travels, thereby moving to a height position corresponding to each shelf 5 shown in FIG. The carry-in conveyor 6 is moved up and down (parallel movement in the vertical direction).

  The downstream carry-out conveyor 7 is configured to be lifted / lowered separately from the carry-in conveyor 6 by the second lifting / lowering means, and the second lifting / lowering means is configured similarly to the first lifting / lowering means. Therefore, the description is omitted.

  However, the first elevating means and the second elevating means are not limited to the above configuration, and for example, a chain, a ball screw, a fluid pressure cylinder, or the like can be used instead of the belt 22.

  Next, the structure of the conveyor which comprises each shelf 5 of the rack 4 is demonstrated. The basic structure of the carry-in conveyor 6 and the carry-out conveyor 7 is also the same as the conveyor (magnetic drive roller conveyor) shown below.

  FIG. 5 is a plan view partially showing a conveyor constituting each shelf of the rack, and FIG. 6 is a side view of the conveyor. 5 and 6, reference numeral 30 denotes a pair of left and right side plates which are parallel to each other, and a plurality of rotating shafts 31 are installed between the both side plates 30 with a predetermined interval. A driving wheel 32 is provided on each rotating shaft 31. Is fixed. These drive wheels 32 are for supporting the conveyed product, and the upper part thereof slightly protrudes above the upper end surface of the side plate 30 as shown in FIG.

  In particular, the rotating shaft 31 passes through one side plate 30 and a cylindrical magnetic wheel 33 is fixed to each end thereof. A drive shaft 34 and an actuator 35 (control motor) that rotationally drives the drive shaft are provided on the outer surface of one side plate 30. Pulleys 36 and 37 are fixed to the drive shaft 34 and the output shaft of the actuator 35, respectively, and a transmission belt 38 is wound around the pulleys 36 and 37.

  The drive shaft 34 is provided so as to be rotatable orthogonally to the respective rotation shafts 31, and is magnetically coupled to the magnetic wheels 33 in the vicinity of the magnetic wheel 33 fixed to one end of each rotation shaft 34 at the outer peripheral portion thereof. A magnetic wheel 39 is fixed. These magnetic wheels 39 are known cylindrical magnet structures in which N poles and S poles are alternately magnetized at a predetermined inclination angle with respect to the central axis as shown in FIG. Power can be transmitted from one to the other while making no contact with the magnetic force.

  According to this example, when each magnetic wheel 39 is rotationally driven in the Y1 direction of FIG. 7 through the drive shaft 34, the driven magnetic wheel 33 adjacent thereto rotates in the Y2 direction of FIG. Thus, the rotary shaft 31 having the drive wheel 32 is rotationally driven all at once in the same direction.

  Therefore, by controlling the actuator 35, the conveyors constituting each shelf 5 can be individually driven (drive wheel 32 is rotationally driven).

  The shelves 5, the carry-in conveyor 6 and the carry-out conveyor 7 constituting the rack 4 are not limited to the magnetic drive type roller conveyors as described above, but are ordinary roller conveyors (drive roller conveyors, wheels) driven by chains or belts. In addition to a conveyor, a belt conveyor can also be used.

  In addition, the actuators 35 are not individually mounted on the conveyors constituting the respective shelves 5, but the drive shafts 34 are connected by a chain or a belt, and a clutch (not shown) is interposed in each drive shaft 34 to each shelf. It is also possible to individually drive and drive the conveyor constituting 5.

  Next, FIG. 8 is a block diagram showing a control means for controlling the driving of the first elevating means and the second elevating means. In FIG. 8, the control means 40 is a computer having a CPU 41, a storage unit 42, and an input unit 43. The storage unit 42 has a ROM for storing a control program and a RAM for storing various data. In the RAM, for example, a data area 42A in which addresses indicating the height positions of the respective shelves 5 are sequentially stored, and a data area 42B in which addresses read from the data area 42A are sequentially stored one by one. , 42C are provided.

  Here, the address of each shelf 5 is sequentially read from the data area 42A by the CPU 41, and the read address is sequentially stored in the data area 42B as warehousing shelf designation data.

  When a warehousing signal is input to the CPU 41 from an external device (for example, an equipment machine located on the upstream side of the carry-in conveyor 6), the travel of the carry-in conveyor 6 is waited at a predetermined height position by the control means 40. After the drive is performed and the conveyed product is mounted on the carry-in conveyor, the drive control of the first elevating means (precisely, the actuator 10 is based on the address (warehousing shelf designation data) stored in the data area 42B in advance. Drive control) is performed, and thereby the carry-in conveyor 6 carrying the conveyed product is moved to the height position of the shelf corresponding to the address of the data area 42B.

  When the carry-in conveyor 6 moves to the height position of the shelf 5 on which the conveyed product is to be loaded, the control means 40 drives the carry-in conveyor 6 and the conveyor that forms the corresponding shelf 5 to move. After the transported goods are carried into the scheduled shelf 5 from the carry-in conveyor 6, their driving is stopped, the carry-in conveyor 6 is returned to the initial standby position in an empty state, and the next transport is performed. The address of the shelf 5 into which the goods are carried is read from the data area 42A, and this is stored in the data area 42B as the latest storage shelf designation data.

  Each shelf 5 is provided with a sensor (not shown) for detecting the presence or absence of a transported object. When the sensor detects a transported object by carrying the transported object into the shelf 5, the transported object is detected in the data area 42A. A flag (for example, “1”) that can identify the presence of the transported object is set in the preceding bit of the shelf address corresponding to the sensor.

  On the other hand, from the data area 42A, the addresses of the respective shelves 5 are read out in the same order as the incoming shelf designation data, and the read addresses are sequentially stored in the data area 42C as outgoing shelf designation data one by one. The second elevating / lowering means is controlled based on the address (delivery shelf designation data) stored in, so that the carry-out conveyor 7 is moved to the height position of the shelf 5 corresponding to the address of the data area 42C.

  And if the carry-out conveyor 7 moves to the height position of the shelf 5 which is going to carry a conveyance thing as mentioned above, the driving means of the conveyor which comprises the carry-out conveyor 7 and the shelf 5 corresponding to this will be performed by the control means 40. Thus, after the conveyed product is unloaded from the planned shelf 5 onto the unloading conveyor 7, the driving of the unloading is stopped, and the unloading conveyor 7 is returned to the initial standby position with the loaded object placed thereon. In addition, the address of the shelf 5 for carrying out the next conveyed product is read from the data area 42A, and this is stored in the data area 42C as the latest delivery shelf designation data.

  When a delivery signal is input from an external device (for example, an equipment machine located on the downstream side of the delivery conveyor 7) to the CPU 41 in a state where the delivery conveyor 7 is returned to the standby position, the delivery conveyor that is on standby. After the travel drive of No. 7 is performed and the conveyed product on the upper side is sent to the downstream side, the drive control of the second lifting / lowering means is performed based on the address (departure shelf designation data) stored in advance in the data area 42C. It is like that.

  As described above, according to the control means 40, the transported articles are carried into the respective shelves 5 in the order in which they are carried in, in the order of the addresses stored in the data area 42B. First-in first-out (conveyed goods) is possible, but the delivery shelf designation data stored in the data area 42C is set by the operator as needed by operating the input unit 43 including operation keys connected to the CPU 41 and a touch panel. It can be changed.

  For this reason, for example, it is possible to change the setting of the delivery shelf designation data to the address of the shelf in which the defective product is carried in, and to carry out the defective product preferentially.

  Here, the control means 40 is not limited to the configuration of first-in-first-out transported goods, for example, all addresses that are not flagged each time from the data area 42A (the shelf identified that the transported goods are not loaded). The address closest to the standby position of the carry-in conveyor 6 is extracted by calculation by the CPU 41, and stored in the data area 42B as storage shelf designation data. On the other hand, the address where the flag is set each time from the data area 42A All of the (shelf identified as being loaded with goods) is read out, the address closest to the standby position of the carry-out conveyor 7 is extracted from it by calculation by the CPU 41, and this is used as the outgoing shelf designation data in the data area 42C. You may make it store in. According to this, while carrying a conveyed product into the empty shelf 5 closest to the standby position of the carry-in conveyor 6, the conveyed product is carried out from the loading shelf 5 closest to the standby position of the carry-out conveyor 7. Can do.

  Next, FIG. 9 shows a usage mode of the present stock apparatus configured as described above. In FIG. 9, 51, 52,... Are various equipment machines (processing machines, etc.) such as a cleaning device and a drying device, which are connected in series in a close state and have a predetermined length (for example, a process line 50). The liquid crystal panel automatic production process line).

  The stock apparatus of the present application (indicated by reference numeral 54 in FIG. 9) is provided at one place on the process line 50 as a bank that prevents the occurrence of subsequent processes due to imbalance in work time between processes and fluctuations in work time. Or it intervenes in several places, and is used for temporarily storing a conveyed product (for example, panel-shaped work-in-process).

  Here, according to the present stock apparatus 54, when the carry-in conveyor 6 exceeds a predetermined height (for example, 1 to 2 m), the passage of the worker in the transverse direction of the process line 50 is performed using the lower region 6A as a passage. It is possible. Further, even when the carry-out conveyor 7 exceeds a predetermined height (for example, 1 to 2 m), the operator can pass in the transverse direction of the process line 50 using the lower region 7A as a passage.

  However, the actuators of the first elevating means and the second elevating means are de-energized so that the carry-in conveyor 6 and the carry-out conveyor 7 do not descend while passing through the lower areas 6A and 7A of the carry-in conveyor and the carry-out conveyor. It is preferable to use an actuated brake motor or the like so that the carry-in conveyor 6 and the carry-out conveyor 7 above the passage are regulated to rise and fall at a predetermined height when the passage is passed.

  As described above, the lower regions 6A and 7A of both the carry-in conveyor 6 and the carry-out conveyor 7 are not limited to passages, and the lower region on at least one side thereof may be used as a passage.

  In short, when at least one of the carry-in conveyor 6 and the carry-out conveyor 7 exceeds a predetermined height, the operator can pass in the transverse direction of the process line 50 using the lower region 6A or 7A on at least one side as a passage. As described above, if at least one lifting / lowering region of the carry-in conveyor 6 and the carry-out conveyor 7 is not closed by a wall made of steel, etc., and has a door or can be opened or is always open type Good.

Schematic side view showing a stock apparatus for conveyed items according to the present invention Schematic plan view of the stock equipment Schematic plan view showing the placement part of the carry-in conveyor Schematic diagram of the front view of the placement part of the carry-in conveyor as viewed from the upstream side Schematic plan view with one shelf partially broken Side view showing the same shelf (conveyor) partially broken Partial perspective view showing one side of the same shelf (conveyor) Block diagram showing a configuration example of the control means Explanatory drawing which shows the use aspect of this application apparatus

Explanation of symbols

4 racks 5 shelves 6 carry-in conveyor 7 carry-out conveyor 10 actuator (drive source for raising and lowering the carry-in conveyor)
11 Guide shaft 12 Transmission system 40 Control means 50 Process line

Claims (3)

  In a stock apparatus that temporarily stores a conveyed product that is interposed in a process line and flows to the line, a rack having a plurality of shelves arranged in a horizontal manner, and the conveyed product to be carried into each of the shelves A carry-in conveyor that can be moved up and down from the rack in the carrying direction of the conveyed product, a first lifting / lowering means that raises and lowers the carry-in conveyor, and conveys the conveyed product from each rack of the rack. An unloading conveyor that can be moved up and down on the downstream side in the conveyance direction of the article, and a second elevating unit that raises and lowers the unloading conveyor, and the carry-on conveyor has a height of a shelf on which the article to be conveyed is loaded. While the unloading conveyor is moved to a height position of a shelf on which the object to be unloaded is placed, and each shelf of the rack is Stock apparatus conveyed object, characterized in that it consists conveyors traveling driven during unloading of conveyed by serial discharge conveyor.   Control means for controlling the driving of the first lifting means and the second lifting means is provided, and the control means includes an address of a shelf for carrying a transported object as storage shelf designation data for controlling the first lifting means, and the second A storage unit for storing an address of a shelf for carrying a transported object as delivery shelf designation data for controlling the elevating means, and an input unit capable of changing the setting of the delivery shelf designation data stored in the storage unit are provided. The stock apparatus for conveyed items according to claim 1. When at least one of the carry-in conveyor and the carry-out conveyor exceeds a predetermined height, an operator can pass in the transverse direction of the process line using a lower region on at least one side as a passage. The stock apparatus of the conveyed product of 1 or 2.

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