JP2011189998A - Method and apparatus for transporting pallet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce transport time by changing pallet transport speeds depending on transport intervals. <P>SOLUTION: A method for transporting pallets includes transporting the pallets 11 mounted on pallet rails 21 and 41 by a plurality of pallet transport means 22 and 42 continuously installed in the longitudinal direction of the pallet rails. The pallet transport speed by the one pallet transport means 22 is different from the other pallet transport speed by the other pallet transport means 42. When the pallets are moved from the one pallet transport means to the other pallet transport means adjacent thereto, the pallet transport speeds in both the one pallet transport means and the other pallet transport means are identical to each other. An apparatus for transporting the pallets includes the pallet rails for mounting the pallets so as to be movable along the longitudinal direction; the plurality of pallet transport means which are continuously installed in the longitudinal direction of the pallet rails, and are capable of changing the pallet transport speeds; and a controller 61 for controlling the plurality of pallet transport means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pallet conveying method and a pallet conveying apparatus for conveying one or more pallets mounted on a pallet rail along the pallet rail.

  2. Description of the Related Art Conventionally, as a device for conveying a workpiece in a production line, a belt conveyor is known in which the workpiece is conveyed by a conveyor and a destination machine tool performs predetermined processing on the workpiece. However, in such a conventional belt conveyor, for example, when a heavy workpiece such as a stator is transported on the conveyor, the inertial force acting on the workpiece when the workpiece is stopped is large. It was difficult to raise and it was difficult to accurately position through the stopper.

  In order to solve such a problem, the present applicant has proposed a pallet transport device that transports a plurality of pallets on which workpieces are placed on a machine tool on a square track (for example, see Patent Document 1). In this transport device, the rear side pallet rail and the front side pallet rail extending in parallel with each other, and the two positions facing the both ends of the back side pallet rail and the front side pallet rail are respectively moved to the respective end parts. A left pallet rail and a right pallet rail that can be connected to each other, and a left pallet feed mechanism and a right pallet feed mechanism that move the plurality of pallets forward and backward along the back pallet rail or the front pallet rail. A plurality of pallets are sandwiched and conveyed between the left pallet feed mechanism and the right pallet feed mechanism. In this way, it is expected that the workpiece conveyance speed and positioning accuracy can be improved by sandwiching and conveying a plurality of pallets between the left pallet feeding mechanism and the right pallet feeding mechanism.

JP 2007-21629 A

  However, in the pallet transport device, a plurality of pallets are sandwiched and transported between the left pallet feed mechanism and the right pallet feed mechanism, so that the transport speed of pallets transported between machine tools is the same for all pallets. However, the problem to be solved still remains that the conveyance speed of the pallet moving between the machine tools cannot be varied depending on the conveyance interval between the machine tools.

  That is, the installation interval of machine tools varies depending on the size and the like, the installation interval of relatively large machine tools tends to increase, and the installation interval of relatively small machine tools tends to narrow. For example, when transporting a heavy workpiece such as a stator, the inertial force acting on the workpiece when the pallet loaded with the relatively heavy workpiece is suddenly started or stopped suddenly is large. It was difficult to increase the conveyance speed between installed machine tools. On the other hand, between machine tools installed at relatively large intervals, since the conveyance interval is relatively long, the conveyance speed between them can be increased, but a machine installed at a relatively large interval is used. If the transport speed between machines is transported at the same speed as the transport speed between machine tools installed at relatively small intervals, the transport takes a relatively long time and includes this transport time. There was a problem that the machining time of multiple machine tools increased.

  An object of the present invention is to provide a pallet transport method and a pallet transport apparatus that can shorten the transport time by changing the transport speed of the pallet according to the transport interval.

  The pallet conveying method of the present invention is a method of conveying a pallet mounted on a pallet rail by a plurality of pallet conveying means provided continuously in the longitudinal direction of the pallet rail.

  The characteristic point is that the pallet transport speed by one pallet transport means is different from the pallet transport speed by another pallet transport means.

  When the pallet moves from one pallet conveying means to another adjacent pallet conveying means, it is preferable that the pallet conveying speed is the same in both the one pallet conveying means and the other pallet conveying means.

  A pallet conveying device according to the present invention includes a pallet rail on which a pallet is movably mounted along a longitudinal direction, and a plurality of pallet conveying units that are continuously provided in the longitudinal direction of the pallet rail and can vary the pallet conveying speed. Means and a controller for controlling the plurality of pallet conveying means. The controller makes the pallet transport speed of one pallet transport means different from the pallet transport speed of another pallet transport means and moves the pallet from one pallet transport means to another adjacent pallet transport means. The pallet transport speed is controlled to be the same in both the one pallet transport means and the other pallet transport means.

  In the pallet conveying method and the pallet conveying apparatus of the present invention, the pallet conveying speed by one pallet conveying means is different from the pallet conveying speed by another pallet conveying means by a plurality of pallet conveying means capable of changing the pallet conveying speed. Can be made. For this reason, it is possible to increase the conveyance speed between machine tools installed at relatively large intervals while lowering the conveyance speed between machine tools installed at relatively small intervals. In this way, the overall transfer time can be shortened by increasing the transfer speed between machine tools installed at relatively large intervals.

It is a figure which shows the pallet conveying apparatus of embodiment of this invention. It is an AA line expanded sectional view of FIG.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 shows a pallet conveying apparatus 10 according to the present invention. The pallet carrying device 10 in this embodiment is configured to carry and carry a plurality of pallets 11, and includes a first pallet carrying device 20 and a second pallet carrying device 40 connected thereto. Although the pallet transport apparatus 10 includes pallet rails 21 and 41 for mounting the pallet 11 so as to be movable along the longitudinal direction, the pallet according to this embodiment includes the first pallet transport apparatus 20 and the second pallet transport apparatus 40. The rail includes a first pallet rail 21 in the first pallet transport device 20 and a second pallet rail 41 in the second pallet transport device 40 connected to the first pallet rail 21.

  The first pallet transport device 20 and the second pallet transport device 40 are connected by a connecting plate 13. The connecting plate 13 is formed of a rectangular plate-like member, and an insertion hole through which the bolt 13a can be inserted is formed around the connection plate 13. On the other hand, although not shown, female screw holes are formed at both ends of the first pallet rail 21 and the second pallet rail 41 at positions corresponding to insertion holes (not shown) of the connecting plate 13. Then, the end portion of the first pallet rail 21 and the end portion of the second pallet rail 41 are brought together or faced with a predetermined interval (FIG. 1 shows a case where they face each other with a predetermined interval). The connecting plate 13 is superposed on the butted or opposed portion, and the insertion hole is matched with the female screw hole. Then, the connecting plate 13 is fixed to both the first pallet rail 21 and the second pallet rail 41 by screwing the bolt 13a inserted through the insertion hole into the female screw hole. Thereby, as shown in the enlarged view of FIG. 1, the first pallet rail 21 and the second pallet rail 41 are connected by the connecting plate 13.

  Here, the first and second pallet conveying devices 20 and 60 have the same structure, and the pallet rail 21 in the first pallet conveying device 20 will be described as a representative. The first pallet rail 21 is shown in FIG. In this way, a support plate 21a provided directly fixed on a gantry (not shown) and a commercially available linear motion guide rail 21b fixed to the upper edge of the support plate 21a by screws are provided. On the other hand, the pallet 11 mounted on the pallet rails 21 and 41 is screwed to the linear motion block 11a configured to be movable on the linear motion guide rail 21b across the linear motion guide rail 21b, and to the block 11a. And a locking member 12 provided on both sides sandwiching the first pallet rail 21 below the pedestal 11b. The linear motion block 11a is a commercially available product sold in pairs with the linear motion guide rail 21b, and preferably includes a roller retainer (not shown). By using such a linear motion block 11a, it is possible to remarkably reduce the resistance of the pallet 11 to move on the pallet rails 21 and 41 while prohibiting the movement of the first pallet rail 21 in the width direction. The pallet 11 is movably mounted on the first and second pallet rails 21 and 41. Although not shown, the pedestal 11b of the pallet 11 is separately attached with a work support portion for storing a work (not shown). Details of the locking member 12 will be described later.

  Returning to FIG. 1, the pallet conveying device 10 includes a plurality of pallet conveying means 22 and 42 provided continuously in the longitudinal direction of the pallet rails 21 and 41. The pallet conveying means 22 and 42 in this embodiment are provided in the first pallet conveying device 20 and the second pallet conveying device 40, respectively. Each of the pallet transporting means 22 and 42 has the same structure, and the first and second pallet transporting means 22 and 42 are provided so as to be circulated endlessly along the first and second pallet rails 21 and 42. Belts 23, 24, 43, and 44, and drive power sources 26 and 46 that circulate the circulation belts 23, 24, 43, and 44, respectively, are provided. In this embodiment, a pair of circulation belts 23, 24, 43, 44 are provided, and first and second drive pulleys 27, 47 around which the pair of circulation belts 23, 24, 43, 44 are respectively wound are first. The first and second pallet rails 21 and 41 are provided at approximately the center in the longitudinal direction of the support plates 21a and 41a or in the vicinity thereof. Then, from the longitudinal direction of the pallet rails 21, 41, the circulation belts 23, 24, 43, 44 are pressed against the first and second drive pulleys 27, 47, and the circulation belts 23, 24, 43, 44 are wound around. Idle pulleys 31 to 34 and 51 to 54 are provided to extend 44 to the side on which the pallet 11 of the first and second pallet rails 21 and 41 is mounted.

  In the first pallet transport device 20, since the pair of circulation belts 23 and 24 wound around the drive pulley 27 provided therein is a pair, the pallet 11 of the first pallet rail 21 mounts the pair of circulation belts 23 and 24. In order to extend to the side, the idle pulleys 31 to 34 are provided on both ends of the first pallet rail 21 in the longitudinal direction and on both sides of the drive pulley 27 provided there, respectively. The idle pulleys 32 and 33 provided on both sides of the drive pulley 27 are configured to urge the pair of circulation belts 23 and 24 against the drive pulley 27 from both sides in the longitudinal direction of the first pallet rail 21. . In addition, idle pulleys 31 and 34 provided on both sides of the first pallet rail 21 in the longitudinal direction of the support plate 21 a have a pair of circulation belts 23 and 24 along the first pallet rail 21 and the first pallet rail 21. The pair of circulation belts 23 and 24, which are guided to the end portion and hung around the drive pulley 27 at the center of the support plate 21a, are extended to both sides of the support plate 21a, and the extended end portions are connected to the first pallet. The rail 21 is configured to be supported at both ends in the longitudinal direction.

  On the other hand, in the second pallet conveying device 40, since the pair of circulation belts 43 and 44 wound around the second drive pulley 47 provided therein is a pair, the pair of circulation belts 43 and 44 are connected to the second pallet rail 41. In order to extend to the side on which the pallet 11 is mounted, the idle pulleys 51 to 54 are provided on both ends of the second pallet rail 41 in the longitudinal direction and on both sides of the second drive pulley 47 provided there. The idle pulleys 52 and 53 provided on both sides of the second drive pulley 47 are configured to urge the pair of circulation belts 43 and 44 against the drive pulley 47 from both sides in the longitudinal direction of the second pallet rail 41. Is done. Further, idle pulleys 51 and 54 provided on both sides of the support plate 41 a in the longitudinal direction of the second pallet rail 41 have a pair of circulation belts 43 and 44 along the second pallet rail 41 and the second pallet rail 41. A pair of circulation belts 43 and 44, which are guided to the end portion and hung around the drive pulley 47 at the center of the support plate 41a, are extended to both sides of the support plate 41a, and the extended end portions are connected to the second pallet. The rail 41 is configured to be supported at both ends in the longitudinal direction.

  Further, in this pallet conveying device 10, the circulation belts 23, 24, 43, 44 are pressed against the drive pulleys 27, 47 from the longitudinal direction of the first and second pallet rails 21, 41, and the circulation belts are laid around them. Auxiliary pulleys 36 to 39 and 56 to 59 are provided for applying a predetermined tension by pulling 23, 24, 43 and 44. In the first pallet transport device 20, since the pair of circulation belts 23 and 24 that are wound around the driving pulley 27 provided there is a pair, the pair of circulation belts 23 and 24 are connected to the first pallet rail 21 from both sides in the longitudinal direction. Auxiliary pulleys 36 to 39 are provided on both ends of the first pallet rail 21 in the longitudinal direction and on both sides of the drive pulley 27 provided on the first pallet rail 21 in order to press and hang around the drive pulley 27. The auxiliary pulleys 37 and 38 provided on both sides of the drive pulley 27 are configured to urge the pair of circulation belts 23 and 24 against the drive pulley 27 from both sides in the longitudinal direction of the first pallet rail 21. .

  On the other hand, in the second pallet transporting device 40 as well, since the pair of circulation belts 43 and 44 wound around the drive pulley 47 provided therein is a pair, the pair of circulation belts 43 and 44 are arranged in the longitudinal direction of the second pallet rail 41. Auxiliary pulleys 56 to 59 are provided on both ends of the second pallet rail 41 in the longitudinal direction and on both sides of the drive pulley 47 provided there, respectively. The auxiliary pulleys 52 and 53 provided on both sides of the drive pulley 47 are configured to urge the pair of circulation belts 43 and 44 against the drive pulley 47 from both sides in the longitudinal direction of the second pallet rail 41. .

  Circulation belts 23, 24, 43, and 44 in this embodiment are so-called toothed belts. Referring to the circulation belts 24 and 43 shown in the enlarged view of FIG. 1, the toothed belts that are the circulation belts 24 and 43 have unevennesses 24a, 24b, 43a, and 43b extending in the width direction alternately in the longitudinal direction. Are formed on the engaging member 12 of the pallet 11 so as to be engaged with the unevennesses 24a, 24b, 43a, 43b. As shown in FIG. 2, the locking members 12 are provided on both sides of the pallet rail 21 on the lower side of the pedestal 11b, and the circulation belts 24, 43 are attached to the locking members 12 provided on both sides. Concavities and convexities 12a and 12b that can be engaged with the toothed belt are formed. The concave and convex portions 12a and 12b are formed on the locking members 12 provided on both sides of the pallet 11, respectively, even when the pallet 11 is mounted with the left and right sides in FIG. , 43 for engagement.

  Returning to the enlarged view of FIG. 1, the engaging member 12 includes uneven belts 12 a and 12 b formed continuously in the longitudinal direction so that the circulation belt 24 in the first pallet conveyance device 20 and the circulation belt in the second pallet conveyance device 40. When the concave and convex portions 12a and 12b on the pallet 11 are engaged with the concave and convex portions 24a, 24b, 43a and 43b, the circulating belt has a length that can be simultaneously engaged with the concave and convex portions 24a, 24b, 43a and 43b. 24, 43 is configured to prohibit the movement of the pallet 11 in the longitudinal direction. Thus, the circulation belts 24 and 43 that are toothed belts are configured such that the pallet 11 mounted on the first and second pallet rails 21 and 41 can be locked, and the circulation belts 23 and 23 on which the pallet 11 is locked. When 24, 43, and 44 are circulated, the pallet 11 moves together with the circulation belts 23, 24, 43, and 44, and the first and second pallet rails 21 and 41 along which the circulation belts 23, 24, 43, and 44 are located. It is comprised so that the pallet 11 can be conveyed along.

  Here, reference numeral 63 in the enlarged view of FIG. 1 and FIG. 2 denotes a support member 63 provided on each of the pallet rails 21 and 41 in order to prevent the circulation belts 24 and 43 from being bent. Preventing the engagement between the unevenness 23a, 23b, 43a, 43b in the circulation belts 23, 43 and the unevenness 12a, 12b in the pallet 11 due to the bending of the circulation belts 24, 43. It is.

  Position adjustment of the four idle pulleys 31 to 34 and the four auxiliary pulleys 36 to 39 in the first pallet transport device 20 and the four idle pulleys 51 to 54 and the four auxiliary pulleys 56 to 59 in the second pallet transport device 40 The pallet rails 21 and 41 are attached to the support plates 21a and 41a via the mechanism 60, respectively. As shown in the enlarged view of FIG. 1, the position adjusting mechanism 60 includes a small rail 60a that extends in the longitudinal direction on each of the support plates 21a and 41a, and a pivot that is movably provided on the small rail 60a. A support 60b, a support 60c attached to the support plates 21a and 41a, and a screw member 60d that is provided on the support 60c and moves the pivot 60b along the small rail 60a. Each of the pulleys 34 and 51 is pivotally supported by a pivot base 60b in the position adjusting mechanism 60. By moving the pivot base 60b by a screw member 60d and adjusting its position in the longitudinal direction, all of the pulleys 34 and 51 are supported. , 51 can be adjusted in the longitudinal direction of the pallet rails 21, 41.

  Further, the first and second pallet conveying means 22 and 42 for conveying the pallet 11 by circulating the circulation belts 23, 24, 43 and 44 are configured to be able to vary the conveying speed of the pallet 11. In this embodiment, servo motors that can change the circulation speed of the circulation belts 23, 24, 43, 44 by changing the rotation speed of the drive pulleys 27, 47 are used as the drive power sources 26, 46, respectively. . The drive power sources 26 and 46, which are servo motors, are attached to the support plates 21a and 41a of the first and second pallet rails 21 and 41, respectively, and drive pulleys 27 and 47 are attached to their rotation shafts. Control outputs from the controller 61 are connected to the servo motors 26 and 46, and when the servo motors 26 and 46 are driven by commands from the controller 61, the rotary shafts to which the drive pulleys 27 and 47 are attached are moved to them. The circulation belts 23, 24, 43, 44 that rotate with the drive pulleys 27, 47 and are wound around the drive pulleys 27, 47 are configured to be circulated as indicated by solid arrows in the figure. In the figure, the servo motor 26 is used as a driving power source. However, as long as the circulation speed of the circulation belts 23, 24, 43, 44 can be varied, an air or hydraulic cylinder or the like is used instead of the servo motor. The driving power sources 26 and 46 may be used.

  Next, the pallet conveying method of the present invention using the pallet conveying apparatus 10 having the above configuration will be described.

  The pallet conveying method of the present invention is a method in which the pallet 11 mounted on the pallet rails 21 and 41 is conveyed by a plurality of pallet conveying means 22 and 42 provided continuously in the longitudinal direction of the pallet rails 21 and 41. In the pallet conveying means 22 and 42 in this embodiment including the circulation belts 23, 24, 43 and 44 made of toothed belts, the pallets 11 mounted on the pallet rails 21 and 41 are provided on the pallets 11. The irregularities 12a and 12b engage with the irregularities 24a, 24b, 43a and 43b of the circulation belts 23, 24, 43 and 44 provided along the pallet rails 21 and 41. Thus, the pallet 11 is locked to the circulation belts 23, 24, 43, 44, and the circulation belts 23, 24 locked by the pallet 11 are circulated by driving the servo motors 26, 46 as drive mechanisms. The pallets 11 can be transported along the rails 21 and 41.

  Further, the pallet transport method of the present invention is characterized in that the transport speed of the pallet 11 by one pallet transport means 22 is different from the transport speed of the pallet 11 by another pallet transport means 42. As the driving power source 26 in one pallet conveying means 22 and the driving power source 46 in another pallet conveying means 42, the rotational speeds of the driving pulleys 27 and 47 are changed, and the circulating speeds of the circulating belts 23, 24, 43 and 44 are changed. The servo motors 26 and 46 are separately provided in the first and second pallet conveying devices 20 and 40, respectively. For this reason, by making the rotational speeds of the drive pulleys 27, 47 by the servo motors 26, 46 different from each other, the circulation speed of the circulation belts 23, 24 in one pallet conveying means 22 and the other pallet conveying means. The circulation speed of the circulation belts 43 and 44 in 42 can be varied.

  The servo motors 26 and 46 are controlled by a controller 61, and the controller 61 makes the circulation speeds of the circulation belts 23, 24, 43, and 44 in the respective pallet conveying means 22 and 42 different. The conveying speed of the pallet 11 is different for each of the pallet conveying means 22 and 42. If the conveying speed of the pallet 11 is varied for each of the pallet conveying means 22 and 42, the feed pitch of the pallet 11 can be changed. For example, reference numerals 1, 2, and 2 in FIG. 1 can be increased while the conveyance speed between the machine tools indicated by reference numerals 3 and 4 in FIG. 1 installed at relatively large intervals is increased. Therefore, by increasing the conveying speed between the machine tools 3 and 4 installed at a relatively large interval, the feed pitch of the pallet 11 can be expanded to match the relatively large interval between the machine tools 3 and 4. Thereby, the conveyance time can be shortened.

  Furthermore, when the pallet 11 moves from one pallet conveying means 22 to another adjacent pallet conveying means 42, both the one pallet conveying means 22 and the other pallet conveying means 42 are provided. The conveying speed of the pallet 11 is the same. That is, the case where the pallet 11 is conveyed in the right direction in FIG. 1 will be described. When the pallet 11 is conveyed and reaches the end of the first pallet rail 21 in one pallet conveying means 22, the pallet 11 is engaged. The circulation belt 24 stopped and extending in the longitudinal direction along the first pallet rail 21 is turned downward by an idle pulley 36. Then, the pallet 11 and the circulation belt 24 are disengaged, and the pallet 11 moves from the first pallet rail 21 to the second pallet rail 41. Then, the pallet 11 moved to the second pallet rail 41 is newly locked by a circulation belt 43 provided along the second pallet rail 41, and the circulation belt 43 circulates along the second pallet rail 41. Is further conveyed.

  Here, although the pallet conveying means 22 and 42 are provided with circulation belts 23, 24, 43, and 44, the circulation belts are formed with concavities and convexities 24a, 24b, 43a, and 43b extending in the longitudinal direction. In such a case, the pallet 11 and the circulation belt can be relatively easily formed by forming the concavo-convex portions 12a and 12b that can be engaged with the concavo-convex portions 24a, 24b, 43a, and 43b on the pallet 11. 24, the pallet 11 can be newly locked to the circulation belt 43.

  However, in order for the pallet 11 to move from the first pallet rail 21 to the second pallet rail 41, the irregularities 24a, 24b, 43a, 43b of the circulation belts 24, 43 are alternately continuous at a predetermined pitch. Since the pitch always changes when the circulation speeds of the circulation belts 23, 24, 43, and 44 are different, the pallet 11 is transferred from one pallet conveyance means 22 to another pallet conveyance means 42 adjacent thereto. Can not be moved. For this reason, when the pallet 11 moves from one pallet conveying means 22 to another adjacent pallet conveying means 42, the controller 61 causes the circulation belts 23, 24, 43, 44 in the respective pallet conveying means 22, 42 to move. By making the circulation speed the same, the conveyance speed of the pallet 11 in both one pallet conveyance means 22 and another pallet conveyance means 42 can be made identical. Then, the unevennesses 24a, 24b, 43a, 43b of the circulation belts 24, 43 can be alternately continued at a predetermined pitch, whereby the movement of the pallet 11 can be ensured.

  In the pallet transport method and apparatus 10 of the present invention, each pallet 11 moves while mounted on the first pallet rail 21 and the second pallet rail 41, so even a heavy workpiece is transported at high speed. It is possible to stop at a predetermined position, and productivity can be improved. Each pallet 11 is locked to circulation belts 23, 24, 43, 44 provided along the first pallet rail 21 and the second pallet rail 41, so that the circulation belts 23, 24, 43, 44 by the controller 61 are used. By accurately controlling the circulation of the pallet 11, the pallet 11 can be positioned with high accuracy. By changing the position of the pallet 11 that engages with the circulation belts 23, 24, 43, and 44, the pitch between the pallets 11 can be changed quickly without changing the pallet 11 itself.

  In the pallet conveying apparatus 10 and method of the present invention, all the idle pulleys 31 to 34 and 51 to 54 and all the auxiliary pulleys 36 to 39 and 56 to 59 are connected to the first and second pallets via the position adjusting mechanism 60. Since the rails 21 and 41 are configured such that their positions can be adjusted in the longitudinal direction, the irregularities 24a and 24b of the pair of circulation belts 23 and 24 sandwiching the drive pulley 27 of the first pallet transport device 20 are at a predetermined pitch. When the belts are not continuous alternately, or the concave and convex portions 43a and 43b of the pair of circulation belts 43 and 44 sandwiching the drive pulley 47 of the second pallet transport device 40 are not continuous at a predetermined pitch. In this case, any one of the idle pulleys 32, 33, 52, 53 on both sides of the drive pulleys 27, 47 by the position adjusting mechanism 60 is used. By adjusting the square or both positions, irregularities 24a thereof circulating belts, 24b, 43a, 43 b can be made continuous alternately at a predetermined pitch. The tensions of the circulation belts 23, 24, 43, and 44 can be easily adjusted by the auxiliary pulleys 36 to 39 and 56 to 59. Therefore, the pallet 11 can be reliably moved between the circulation belts 23, 24, 43, 44.

  In the above-described embodiment, the pallet rail in which the first pallet rail 21 and the second pallet rail 41 are connected by the connecting plate 13 has been described. However, the connection between the first pallet rail 21 and the second pallet rail 41 is not limited to this. The connection plate 13 may be connected to the structure, or the first pallet rail 21 and the second pallet rail 41 may be connected without using the connection plate 13. The pallet rail may be a single pallet rail as long as the plurality of conveying means 22 and 42 are continuously provided in the longitudinal direction.

  Further, in the above-described embodiment, the case where the drive pulleys 27 and 47 are provided at substantially the center portions of the pallet rails 21 and 41 has been described, but although not illustrated, the first and second pallet rails 21 and 41 are not illustrated. The driving pulleys 27 and 47 may be provided at one end in the longitudinal direction, and an idle pulley may be provided at the other end so that the circulation belt extends along the longitudinal direction.

DESCRIPTION OF SYMBOLS 10 Pallet conveying apparatus 11 Pallet 21,41 Pallet rail 22 One pallet conveying means 42 Another pallet conveying means 61 Controller

Claims (3)

In this method, the pallet (11) mounted on the pallet rail (21, 41) is transported by a plurality of pallet transport means (22, 42) provided continuously in the longitudinal direction of the pallet rail (21, 41). And
A pallet conveying method, characterized in that a conveying speed of the pallet (11) by one pallet conveying means (22) is different from a conveying speed of the pallet (11) by another pallet conveying means (42).   When the pallet (11) moves from one pallet conveying means (22) to another adjacent pallet conveying means (42), both the one pallet conveying means (22) and the other pallet conveying means (42) The pallet conveyance method according to claim 1, wherein the pallet (11) has the same conveyance speed. Pallet rails (21, 41) for mounting the pallet (11) movably along the longitudinal direction;
A plurality of pallet conveying means (22, 42) provided continuously in the longitudinal direction of the pallet rails (21, 41) and configured to be able to vary the conveying speed of the pallet (11);
A controller (61) for controlling the plurality of pallet conveying means (22, 42),
The controller (61) makes the conveying speed of the pallet (11) by one pallet conveying means (22) different from the conveying speed of the pallet (11) by another pallet conveying means (42), and When the pallet (11) moves from the pallet conveying means (22) to the adjacent another pallet conveying means (42), both the one pallet conveying means (22) and the other pallet conveying means (42) The pallet carrying device is controlled so that the carrying speed of the pallet (11) is the same.

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