Material handling equipment

Abstract

To provide an article conveyance device having high versatility by broadening an extensive general purpose range of articles holdable with a gripper.SOLUTION: A linear conveyance device 6 has a lot of movable elements 16A, 16B having grip pieces 3A, 3b, and a gripper 3 holding a container 2 by the adjacent pair of the grip pieces 3A, 3B is formed. One grip piece 3A out of the adjacent pair of the grip pieces is decentered to the upstream side in the conveying direction in relation to an axis of the movable element 16A provided therewith, and the other grip piece 3B is decentered to the downstream side in the conveying direction of the movable element 16B provided therewith. When holding the minimum container 2, the container is held by a first mode consisting of a second holding face 3Adb of the grip piece 3A and a first holding face 3Bda of the grip piece 3B, and when holding the maximum container 2, the container is held by a second mode consisting of a first holding face 3Ada of the grip piece 3A and a second holding face 3Bdb of the grip piece 3B.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to an article conveying device, and more particularly to an article conveying device using a linear motor, which holds and conveys an article by grippers provided across a pair of adjacent movers.

Background Art

[0002] Conventionally, a linear conveying device configured to convey an article using a linear motor has been known (see, for example, Patent Document 1 and Patent Document 2). In such a conventional linear conveying device, one grip piece is attached to one mover, and an article is conveyed while holding the front and rear of the article by a gripper (holding means) composed of a pair of adjacent grip pieces.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the above conventional linear conveying device, when attempting to hold articles having different dimensions in the conveying direction, the interval between adjacent movers is adjusted to change the interval between a pair of adjacent grip pieces so as to match the dimensions of the article. Specifically, when holding an article having a small dimension in the conveying direction with the gripper, the interval between a pair of adjacent grip pieces, that is, the interval between adjacent movers, is set narrow, and when holding an article having a large dimension in the conveying direction with the gripper, it is necessary to set the interval between a pair of adjacent grip pieces, that is, the interval between the movers, wide. Incidentally, since the gripping piece is attached to the movable part, when holding a small item with the gripper, the limit was the position where adjacent movable parts did not interfere with each other. Furthermore, for example, if the item is a container and the container is held by multiple grippers, each consisting of a pair of grip pieces, and then transported to a filling device for filling with liquid, the pitch of adjacent containers must match the pitch of adjacent filling nozzles in the filling device. Therefore, when holding a large container with a gripper, the limit was the position where it would not interfere with the movable part of the gripper holding the adjacent container. In this case, increasing the range of motion of the movable part would also increase the pitch of the filling nozzles, resulting in a larger filling device itself, higher manufacturing costs, and thus undesirable. Therefore, the object of the present invention is to provide an article conveying device equipped with a gripper that can broaden the range of articles that can be held, even if there is a limit to the range of movement of adjacent movable elements equipped with grippers. [Means for solving the problem]

[0005] In view of the circumstances described above, the present invention comprises a number of movable elements arranged along a predetermined transport path, a stator for linearly driving each of the movable elements along the transport path, and one grip piece provided on one of two adjacent movable elements, and the other grip piece provided on the other movable element. In an article conveying device in which a gripper is formed by the gripping pieces of two adjacent movable elements, and the two adjacent movable elements are moved synchronously to convey the article held by the gripper along the conveying path, Each of the grip pieces described above has a first holding surface formed on the upstream side in the direction of conveying the article, and a second holding surface formed on the downstream side in the direction of conveying the article. The first and second retaining surfaces of one adjacent grip piece are provided eccentrically on the upstream side in the conveying direction relative to the movable element on which the grip piece is attached, and the first and second retaining surfaces of the other adjacent grip piece are provided eccentrically on the downstream side in the conveying direction relative to the movable element on which the grip piece is attached, The two grip pieces are alternately placed along the transport path described above. Furthermore, one of the adjacent movable elements is provided with a first connecting shaft extending along the conveying direction, and a first through-hole is drilled along the conveying direction. The other adjacent movable element is provided with a second connecting shaft extending along the conveying direction and a second through-hole drilled along the conveying direction. The first connecting shaft of one of the above-mentioned movable elements can pass through the second through-hole of the other movable element, and the second connecting shaft of the other movable element can pass through the first through-hole of the first movable element. In a first mode, the movable element with one of the grip pieces is positioned upstream in the transport direction, and the other movable element with the other grip piece is positioned downstream in the transport direction, and the article is held by the second holding surface of the first grip piece and the first holding surface of the other grip piece. The other movable element, which is equipped with the other grip piece, is positioned on the upstream side in the conveying direction, and the first movable element, which is equipped with the first grip piece, is positioned on the downstream side in the conveying direction. This allows switching to a second mode in which the article is held by the second holding surface of the other grip piece and the first holding surface of the first grip piece. [Effects of the Invention]

[0006] With this configuration, by switching the gripper between the first and second modes depending on the size of the container, the range of items that can be held by the gripper can be broadened. Therefore, a highly versatile item handling device can be provided. [Brief explanation of the drawing]

[0007] [Figure 1] A plan view showing one embodiment of the present invention. [Figure 2] Figure 2(a) is an enlarged view of the main part of Figure 1, Figure 2(b) is a rear view of the main part of Figure 1, and Figure 2(c) is a longitudinal cross-sectional view of the main part of Figure 1. [Figure 3] Enlarged view of the main part of Figure 1. [Figure 4] Figure 2 is a plan view showing the container being held by the gripper, Figure 4(a) shows the smallest container being held by the first mode gripper, and Figure 4(b) shows the largest container being held by the second mode gripper. [Figure 5]Figure 5(a) is a plan view showing the case where the smallest container is held by a conventional gripper, and Figure 5(b) is a plan view showing the case where the largest container is held by a conventional gripper. [Figure 6] Figure 6(a) is a plan view showing the smallest container being held by the gripper in the first mode of the present invention, and Figure 6(b) is a plan view showing the largest container being held by the gripper in the second mode of the present invention. [Modes for carrying out the invention]

[0008] The present invention will now be described with reference to the illustrated embodiments. In Figures 1 and 2, 1 is a filling system for filling a container 2 with liquid. This filling system 1 has a number of grippers 3 that hold the container 2 which are circulated along a circulating transport path R in the direction of the arrow. After the container 2 is supplied to the grippers 3 stopped at supply position A by a supply robot 4 and held, the container 2 held by the grippers 3 is transported to filling position B and stopped, where a predetermined amount of liquid is filled into the container 2 by a filling device 5. The filling system 1 includes a linear conveying device 6 as an article conveying device that holds and conveys containers 2 with a gripper 3, a supply robot 4 positioned at supply position A in the circulating conveying path R of the linear conveying device 6 to supply empty containers 2 to the gripper 3, a filling device 5 positioned at filling position B downstream of supply position A in the circulating conveying path R to fill liquid into containers 2, a capping device 7 provided at capping position C downstream of filling position B in the circulating conveying path R, an inspection device 8 provided at inspection position D downstream thereof to inspect containers 2, a discharge robot 9 provided at discharge position E downstream of inspection position D, and a control device 11 that controls the operation of these components, etc.

[0009] Although not shown in Figure 1, a Ferriplate 12 is positioned to support the bottom of the container 2 from the supply position A to the discharge position E downstream in the transport direction. The container 2, which is held and transported by the gripper 3, is supported by the Ferriplate 12 and slides along its surface. A nut member 13 is connected to the lower part of the Ferriplate 12, and this nut member 13 is screwed onto a ball screw 14 positioned vertically (see Figure 2(c)). The ball screw 14 is rotated by a servo motor M1, and the operation of this servo motor M1 is controlled by a control device 11. If the height or shape of the container 2 to be processed is changed, the control device 11 rotates the servo motor M1 by the required amount, thereby changing the height of the Ferriplate 12. This allows the gripper 3 to hold the body of the container 2 at a suitable height position. A linear supply conveyor 15 is positioned parallel to the circulating transport path R at supply position A, and empty containers 2 arranged in a vertical line in an upright position are supplied to supply device A by the supply conveyor 15 and stopped there. A supply robot 4 is positioned at supply device A, and the supply robot 4 grasps the empty containers 2 on the supply conveyor 15, widens the spacing between adjacent containers 2, and then has the containers 2 held by eight grippers 3 that are stopped on the ferriplate 12 at supply position A. As will be described in detail later, the gripper 3 consists of a grip piece 3A provided on one adjacent movable element 16A and a grip piece 3B provided on the other adjacent movable element 16B, and the body of the container 2 is held from the front and rear in the direction of transport by this pair of adjacent grip pieces 3A and 3B (see Figure 3). As mentioned above, the container 2 held by the gripper 3 is supported by the ferriplate 12 and slides on its surface. The container 2, into which the liquid is filled, has a body and an upper opening, and the liquid is filled into the interior from the upper opening. Alternatively, the container 2 may be held solely by the gripper 3 without the placement of the ferriplate 12.

[0010] The linear conveying device 6, as an article conveying device, comprises a pair of upper and lower rails 17 arranged along an endless circulating conveying path R, an electromagnetic coil unit 18 arranged across the entire circulating conveying path R between the upper and lower rails 17 and having numerous electromagnetic coils provided at predetermined intervals inside, and numerous movable elements 16A, 16B arranged adjacent to the electromagnetic coil unit 18 and guided by the rails 17 to move along the circulating conveying path R. The electromagnetic coil unit 18 constitutes the stator of the linear motor for the movable elements 16A, 16B. Furthermore, each movable element 16A and 16B is the same size and is arranged alternately in a line along the circulating conveying path R. As a result, the grip pieces 3A and 3B are also arranged alternately along the circulating conveying path R. Permanent magnets 19A and 19B are embedded in these movable elements 16A and 16B, facing the electromagnetic coil unit 18, and multiple rollers 16Aa and 16Ba are rotatably provided in vertical positions that roll along the guide surfaces of the upper and lower rails 17. The numerous electromagnetic coils located within the electromagnetic coil unit 18 are individually energized at the required timing by the control device 11. The control device 11 synchronizes the movement of a pair of adjacent movable elements 16A and 16B along the circulating transport path R, thereby moving each gripper 3, consisting of grip pieces 3A and 3B attached to the pair of movable elements 16A and 16B, along the circulating transport path R, and also allows for individual control of the movement position and speed during the movement. By exciting the electromagnetic coil at the required position along the circulation conveyance path R, the gripper 3 provided across the pair of adjacent movers 16A and 16B can be circulated and run at a predetermined speed at each position A to E along the circulation travel path R and stopped at the required position. Thereby, the container 2 held by the gripper 3 is conveyed from the supply position A to the discharge position E by the linear conveyance device 6. Further, by adjusting the interval in the conveyance direction between the pair of adjacent movers 16A and 16B by the control device 11, the interval between the pair of grip pieces 3A and the grip piece 3B can be adjusted, whereby containers 2 having different sizes can be held in common by the gripper 3. Note that the basic configuration of the linear conveyance device that moves the mover by linear drive is conventionally well-known, and thus detailed description thereof is omitted here.

[0011] Here, first, referring to FIG. 1, an outline of the conveyance of the container 2 by the gripper 3 of the linear conveyance device 6 and the processing performed at each position A to E will be described. When the eight grippers 3 are stopped above the ferrule plate 12 at the supply position A and the upright empty container 2 is supplied to the supply device A by the supply conveyor 15, the supply robot 4 grips the empty container 2 on the supply conveyor 15 and then widens the interval between the adjacent containers 2 and causes the eight grippers 3 stopped at the supply position A to hold the container 2. At this time, as described above, the bottom of the container 2 is supported by the ferrule plate 12. When the container 2 is held by the gripper 3 at the supply position A, the six grippers 3 holding the empty container 2 are moved to the filling position B and stopped. The filling device 5 is provided with six filling nozzles (not shown) at equal pitches along the conveyance direction of the container 2, and the containers 2 held by the six grippers 3 and stopped at the filling position B are located below the six filling nozzles. Then, a predetermined amount of liquid is filled into the six containers 2 by the filling nozzles of the filling device 5. After that, the six grippers 3 holding the liquid-filled containers 2 are conveyed to the capping position C and stopped there. A capping device 7 is arranged at the capping position C, and caps are attached by the capping device 7 to the upper port portions of the six containers 2 to be closed. After that, the gripper 3 holding the container 2 with the cap attached is conveyed to the inspection position D and stopped. An inspection device 8 is arranged at the inspection position D, and the inspection device 8 inspects for the presence or absence of foreign matter, capping defects, etc. for every four containers 2. The containers 2 that have completed the inspection by the inspection device 8 at the inspection position D are then conveyed to the discharge device E and stopped. A discharge robot 9 and a discharge conveyor 21 are arranged at the discharge position E, and the discharge robot 9 takes out four containers 2 at a time from the gripper 3 stopped at the discharge position E and delivers them onto the discharge conveyor 21. The containers 2 delivered onto the discharge conveyor 21 are conveyed downstream. On the other hand, the gripper 3 that has been emptied by taking out the container 2 at the discharge position E is moved to the supply position A and stopped there again. Note that the containers 2 determined to be defective as a result of the inspection by the inspection device 8 are rejected from the discharge conveyor 21 by a reject device (not shown) after being delivered to the discharge conveyor 21. Thus, the filling system 1 of this embodiment sequentially conveys the containers 2 held by the grippers 3 of the linear conveying device 6 along the circulation conveying path R from the supply position A to the discharge position E, and performs filling of the liquid into the containers 2, subsequent capping, and required inspections.

[0012] Hereinafter, referring to FIGS. 2 to 4, the configuration of a pair of adjacent movers 16A, 16B in the conveying direction and the grip pieces 3A, 3B of the grippers 3 provided thereon will be described. Base members 22A, 22B are horizontally connected to the upper portions of the respective movers 16A, 16B, and rotating shafts 23A, 23B are fixed to the upper surfaces of these base members 22A, 22B so as to face vertically upward. Each grip piece 3A and 3B is the same size and consists of a rectangular prism-shaped base 3Aa and 3Ba and a retaining portion 3Ab and 3Bb integrally provided on its tip side. Vertical through holes 3Ac and 3Bc are drilled in the base 3Aa and 3Ba of the grip pieces 3A and 3B. The upper small-diameter portion of the rotation axis 23A of one adjacent movable element 16A is rotatably passed through the through hole 3Ac of the grip piece 3A, and the upper small-diameter portion of the rotation axis 23B of the other adjacent movable element 16B is rotatably passed through the through hole 3Bc of the grip piece 3B. As a result, adjacent grip pieces 3A and 3B are supported horizontally at the same height, and are rotatable relative to the rotation axes 23A and 23B, respectively. A first retaining surface 3Adb, which is V-shaped in plan view, is formed on the side of the grip piece 3A's retaining portion 3Ab facing upstream in the conveying direction, and a second retaining surface 3Ada, which is V-shaped in plan view, is formed on the side facing downstream in the conveying direction. Furthermore, a first holding surface 3Bdb, which is V-shaped in plan view, is formed on the side of the grip piece 3Bb facing upstream in the conveying direction, and a second holding surface 3Bda, which is V-shaped in plan view, is formed on the side facing downstream in the conveying direction. Thus, since the first holding surfaces 3Adb, 3Bdb and the second holding surfaces 3Ada, 3Bda are formed on both the upstream and downstream sides of each grip piece 3A and 3B in the transport direction, a first mode gripper 3 can be configured to hold the container 2 by the first holding surface 3Adb of grip piece 3A and the second holding surface 3Bda of grip piece 3B, as shown in Figure 4(a). Alternatively, a second mode gripper 3 can be configured to hold the container 2 by the second holding surface 3Ada of grip piece 3A and the first holding surface 3Bdb of grip piece 3B, as shown in Figure 4(b). Furthermore, in this embodiment, the center of the holding portion 3Ab of the grip piece 3A in the transport direction is eccentric by a predetermined amount (for example, 10 mm) upstream in the transport direction relative to the axis of the movable element 16A on which the grip piece 3A is attached. In other words, the first holding surface 3Adb facing upstream in the transport direction and the second holding surface 3Ada facing downstream in the transport direction of the grip piece 3A are eccentric by a predetermined amount upstream in the transport direction relative to the movable element 16A. On the other hand, the center of the holding portion 3Bb of the grip piece 3B in the transport direction is eccentric by a predetermined amount (for example, 10 mm) downstream in the transport direction with respect to the axis of the movable element 16B on which the grip piece 3B is attached. In other words, the first holding surface 3Bdb facing upstream in the transport direction and the second holding surface 3Bda facing downstream in the transport direction of the grip piece 3B are eccentric by a predetermined amount downstream in the transport direction with respect to the movable element 16B. As a result, as shown in Figure 4(a), when holding a small container 2, grip piece 3A is positioned on the downstream side in the conveying direction and grip piece 3B is positioned on the upstream side in the conveying direction, and the container 2 is held by the first holding surface 3Adb of grip piece 3A and the second holding surface 3Bda of grip piece 3B (first mode gripper 3). On the other hand, as shown in Figure 4(b), when holding a large container 2 with the gripper 3, grip piece 3A is positioned on the upstream side in the conveying direction and grip piece 3B is positioned on the downstream side in the conveying direction, and the container 2 is held by the second holding surface 3Ada of grip piece 3A and the first holding surface 3Bdb of grip piece 3B (second mode gripper 3). In other words, in this embodiment, the control device 11 switches the arrangement of an adjacent pair of movable elements 16A and 16B to the upstream and downstream sides, thereby enabling a switch between a first mode gripper 3 in which the container 2 is held by the first holding surface 3Adb of grip piece 3A and the second holding surface 3Bda of grip piece 3B, and a second mode gripper 3 in which the container 2 is held by the second holding surface 3Ada of grip piece 3A and the first holding surface 3Bdb of grip piece 3B.

[0013] Furthermore, in this embodiment, adjacent movable elements 16A and 16B, each provided with the grip pieces 3A and 3B, can be connected to one another via connecting shafts 25A and 25B provided on the grip pieces 3A and 3B, respectively, and the connection can be released. The base 3Aa of the grip piece 3A is connected to the downstream end of the first connecting shaft 25A, which is horizontally supported toward the upstream side in the conveying direction. Furthermore, a horizontal through hole 3Ae is drilled in the base 3Aa of the grip piece 3A, on the side below the first connecting shaft 25A, along the conveying direction. The base 3Ba of the grip piece 3B is connected to the downstream end of the second connecting shaft 25B, which is horizontally supported toward the upstream side in the conveying direction. Furthermore, a horizontal through hole 3Be is drilled in the base 3Ba of the grip piece 3B, above the second connecting shaft 25B, along the conveying direction. The free end of the first connecting shaft 25A of grip piece 3A is slidably able to pass through the through hole 3Be of the adjacent upstream grip piece 3B. Furthermore, the free end of the second connecting shaft 25B of grip piece 3B is slidably able to pass through the through hole 3Ae of the adjacent upstream grip piece 3A. With this configuration, in the case of the gripper 3 in the first mode, where grip piece 3A is positioned on the downstream side in the conveying direction and grip piece 3B is positioned on the upstream side in the conveying direction, both grip pieces 3A and 3B can be connected by the first connecting shaft 25A, as shown in Figure 2(b). In the case of the gripper 3 in the second mode, where grip piece 3A is positioned on the upstream side in the conveying direction and grip piece 3B is positioned on the downstream side in the conveying direction, both grip pieces 3A and 3B can be connected by the second connecting shaft 25B. In the linear transport path (positions A to E above) of the circulating transport path R, as shown in Figures 2 to 4, the first connecting shaft 25A of the grip piece 3A is slidably fitted into the through hole 3Be of the adjacent upstream grip piece 3B. As a result, adjacent movable elements 16A and 16B are connected and can move closer or further apart synchronously, and the pair of grip pieces 3A and 3B provided on the pair of movable elements 16A and 16B can move closer or further apart in the transport direction while maintaining a parallel state. Thus, containers 2 of different sizes can be held by the opposing first holding surfaces 3Adb, 3Bdb and second holding surfaces 3Ada, 3Bda of the pair of grip pieces 3A and 3B provided on the adjacent pair of movable elements 16A and 16B. As mentioned above, the upper small-diameter portions of the rotating shafts 23A and 23B are rotatably fitted into the through holes 3Ac and 3Bc of the grip pieces 3A and 3B, so that the grip pieces 3A and 3B can swing relative to the rotating shafts 23A and 23B and the movable elements 16A and 16B located below them. As shown in Figure 3, in this embodiment, when the gripper 3, consisting of a pair of grip pieces 3A and 3B, moves along a straight section of the circulating transport path R while holding the container 2, the distance between adjacent grippers 3 is narrowed, and the second connecting shaft 25B of the grip piece 3B located downstream in the transport direction is in a state where it passes through the through hole 3Ae of the grip piece 3A located upstream in the transport direction. When moving along a curved section, the distance between adjacent grippers 3 is widened immediately before that point, so that the second connecting shaft 25B is withdrawn from the through hole 3Ae. As a result, when the gripper 3 holding the container 2 moves along the corner of the circulating transport path R, the connection with the subsequent gripper 3 is released, and the grip pieces 3A and 3B are rotated relative to the rotating shafts 23A and 23B so as to maintain parallelism between the container 2 and the first connecting shaft 25A, allowing for smooth movement along the curved section. Although the first connecting shaft 25A and the second connecting shaft 25B are provided facing upstream in the conveying direction, they may also be formed to extend downstream in the conveying direction. In that case, through holes should be drilled in the grip piece on the downstream side, through which the first connecting shaft 25A and the second connecting shaft 25B can slide freely.

[0014] Figures 4(a) and 4(b) show specific examples of how the linear conveying device 6 and its gripper 3, configured as described above, can hold containers 2 of different sizes. When holding the smallest container 2 that can be held, as shown in Figure 4(a), grip piece 3A is positioned on the downstream side in the conveying direction and grip piece 3B is positioned on the upstream side in the conveying direction, and the container 2 is held by the first holding surface 3Adb of grip piece 3A and the second holding surface 3Bda of grip piece 3B (first mode). On the other hand, when holding the largest container 2 that can be held, as shown in Figure 4(b), grip piece 3A is positioned on the upstream side in the conveying direction and grip piece 3B is positioned on the downstream side in the conveying direction, and the container 2 is held by the second holding surface 3Ada of grip piece 3A and the first holding surface 3Bdb of grip piece 3B (second mode). Furthermore, when holding containers 2 of intermediate size between the smallest and largest containers 2 that can be held with the gripper 3, the distance between adjacent pairs of movable elements 16, 16 in the gripper 3 of the first mode or second mode is adjusted. By changing the distance between the pair of grip pieces 3A, 3B that make up the gripper 3, containers of intermediate size 2 can be smoothly held by the gripper 3. Note that in Figures 4(a) and 4(b), the position of the second connecting shaft 25B is shown slightly off-center from the first connecting shaft 25A, rather than directly below, in order to make the relationship between the first connecting shaft 25A and the second connecting shaft 25B easier to understand.

[0015] With the linear transport device 6 of this embodiment configured as described above, the versatility of the containers 2 that can be held can be expanded compared to the conventional technology in which grippers are provided across adjacent movable elements. Here, using Figures 5 and 6, we will compare and explain the differences between a conventional gripper and the gripper 3 of this embodiment when filling liquid using a filling device equipped with multiple filling nozzles. In Figures 5 and 6, the container 2 is assumed to be transported from left to right. Figure 5 shows the conventional technology. Figure 5(a) shows the gripper 3 holding the smallest container 2 that can be held with adjacent movable elements 16A and 16B as close together as possible. Figure 5(b) shows the gripper 3 holding the largest container 2 that can be held with adjacent movable elements 16A and 16B as far apart as possible. In contrast, the conventional gripper 3 has a holding surface for holding the container 2 formed only on one of the mutually opposing surfaces of the grip pieces 3A and 3B, and the container 2 is held by the gripper 3 consisting of a pair of adjacent grip pieces 3A and 3B. Here, the pitch between adjacent filling nozzles in the filling device is L mm, the dimensions of each movable element 16A and 16B are the same, and the position when adjacent movable elements 16A and 16B are closest together is the same as the position when they are most far apart. In a conventional gripper 3, if the grip pieces 3A and 3B are fixedly positioned at the center (center in the transport direction) of each movable element 16A and 16B, the container 2 that can be held by the grip pieces 3A and 3B will be at a minimum size shown by the dashed line in Figure 5(a) and at a maximum size shown by the dashed line in Figure 5(b). In contrast to such conventional technologies, the gripper 3 of this embodiment has the center of the grip piece 3A located downstream in the conveying direction offset by a predetermined amount upstream in the conveying direction relative to the axis of the movable element 16A on which it is provided, and the center of the grip piece 3B located upstream in the conveying direction offset by a predetermined amount downstream in the conveying direction relative to the axis of the movable element 16B on which it is provided. In the first mode of gripper 3, where the container 2 is held by the first holding surface 3Adb of grip piece 3A and the second holding surface 3Bda of grip piece 3B, as shown in Figure 6(a), it is possible to hold an even smaller container 2, shown by the solid line, compared to the smallest container 2 that can be held by the conventional technology, shown by the dashed line. In other words, it is possible to hold a container 2 smaller than conventionally by the amount by which the grip pieces 3A and 3B are eccentrically positioned relative to their movable elements 16A and 16B. Furthermore, as shown in Figure 6(b), in the case of the second mode gripper 3, which holds the container 2 with the second holding surface 3Ada of grip piece 3A and the first holding surface 3Bdb of grip piece 3B, it is possible to hold an even larger container 2, shown by the solid line, compared to the largest container 2 that can be held by the conventional technology, shown by the dashed line. In other words, it is possible to hold a larger container 2 than in the conventional method by the amount by which the grip pieces 3A and 3B are eccentrically positioned relative to their movable elements 16A and 16B. Therefore, according to the linear conveying device 6 of this embodiment, even if there is a limit to the range of movement of the movable elements 16A and 16B that move an adjacent pair of grip pieces 3A and 3B, the range of containers 2 that can be held can be widened by switching between the first mode and the second mode gripper 3 according to the size of the container 2, thus providing a highly versatile linear conveying device 6.

[0016] Although the above embodiment describes a case in which a container 2 is held and transported by the gripper 3 of the linear transport device 6 and liquid is filled into the container 2, the linear transport device 6 of this embodiment can also be used when other items are held and transported by the gripper 3, not just containers 2. Furthermore, the shapes of the first retaining surface 3Adb and the second retaining surface 3Ada of grip piece 3A, and the first retaining surface 3Bdb and the second retaining surface 3Bda of grip piece 3B do not all need to be the same. The shapes of the first retaining surface 3Adb and the second retaining surface 3Ada of grip piece 3A may be different, and the shapes of the first retaining surface 3Bdb and the second retaining surface 3Bda of grip piece 3B may also be different. However, even in that case, the shapes of the first retaining surface 3Adb of grip piece 3A and the second retaining surface 3Bda of grip piece 3B, and the shapes of the second retaining surface 3Ada of grip piece 3A and the first retaining surface 3Bdb of grip piece 3B must be the same. [Explanation of Symbols]

[0017] 2...Container (item) 3...Gripper 3A...Grip piece 3B...Grip piece 6…Linear transport device (material transport device) 16A, 16B…Movement 3Adb, 3Bdb...1st holding surface 3Ada, 3Bda...2nd holding surface 18…Electromagnetic coil unit (stator) R…Circulation transport path

Claims

[Claim 1] The system comprises a number of movable elements arranged along a predetermined transport path, a stator for linearly driving each of the movable elements along the transport path, and one grip piece provided on one of two adjacent movable elements, and the other grip piece provided on the other movable element. In an article conveying device in which a gripper is formed by the gripping pieces of two adjacent movable elements, and the two adjacent movable elements are moved synchronously to convey the article held by the gripper along the conveying path, Each of the grip pieces described above has a first holding surface formed on the upstream side in the direction of conveying the article, and a second holding surface formed on the downstream side in the direction of conveying the article. The first and second retaining surfaces of one adjacent grip piece are provided eccentrically on the upstream side in the conveying direction relative to the movable element on which the grip piece is attached, and the first and second retaining surfaces of the other adjacent grip piece are provided eccentrically on the downstream side in the conveying direction relative to the movable element on which the grip piece is attached, The grip piece on one side and the grip piece on the other side are arranged alternately along the transport path. Furthermore, one of the adjacent movable elements is provided with a first connecting shaft extending along the conveying direction and a first through hole drilled along the conveying direction. The other adjacent movable element is provided with a second connecting shaft extending along the conveying direction and a second through-hole drilled along the conveying direction. The first connecting shaft of one of the above-mentioned movable elements is capable of passing through the second through-hole of the other movable element, and the second connecting shaft of the other movable element is capable of passing through the first through-hole of the one movable element. In a first mode, the movable element with one of the grip pieces is positioned upstream in the transport direction, and the other movable element with the other grip piece is positioned downstream in the transport direction, and the article is held by the second holding surface of the first grip piece and the first holding surface of the other grip piece. An article conveying device characterized in that the other movable element, which is provided with the other grip piece, is positioned on the upstream side in the conveying direction, and the one movable element, which is provided with the first grip piece, is positioned on the downstream side in the conveying direction, and the device is switchable to a second mode in which the article is held by the second holding surface of the other grip piece and the first holding surface of the first grip piece.

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