Automated Guided Vehicle System

Abstract

This system provides an automated guided vehicle (AGV) system that allows the transport platform used for transport to be stored in a small space without the need for special equipment. [Solution] The present invention relates to an automated guided vehicle (AGV) system comprising an AGV, a transport platform, a stacking station, and a controller for controlling the AGV, wherein the controller is configured to perform the following steps: (A) step A, which moves the AGV carrying the first transport platform to the underside of the second transport platform placed on the stacking station; (B) step B, which raises the lifting platform to lift the first transport platform and the second transport platform; (C) step C, which moves the AGV in a first direction to a position where each leg of the first transport platform can be placed on the stacking station; (D) step D, which lowers the lifting platform to place the first transport platform on the stacking station; and (E) step E, which moves the AGV to a safe place.

Description

Technical Field

[0001] The present invention relates to an automated guided vehicle system, and more particularly to an automated guided vehicle system that transports goods using a transport mounting table.

Background Art

[0002] In a transport vehicle system using a traveling carriage or the like, transportation may be performed using a pallet or the like for loading goods. Such transportation using a pallet or the like has the advantage that a large number of goods can be loaded on one traveling carriage or the like. However, in a transport vehicle system using a pallet, there is a problem that a large space is required to store unused pallets.

[0003] On the other hand, Japanese Patent Application Laid-Open No. 5-254662 (Patent Document 1) describes a pallet storage device. This pallet storage device includes a frame, two sets of upper and lower claws, a lifter, and a chain conveyor. The pallet transferred from the traveling carriage to the chain conveyor is lifted by the lifter and delivered to the lower claws. Further, when a predetermined number of pallets are held by the lower claws, these pallets are lifted by the lifter and transferred to the upper claws. Thus, by using the pallet storage device described in Patent Document 1, a plurality of pallets can be stacked and stored, and the space required for storing unused pallets can be reduced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By using a pallet storage device such as the one described in Patent Document 1, it becomes possible to store unused pallets in a small space. However, in order to achieve pallet storage in a small space, a special device such as a pallet storage device is required, which leads to the problem of increased costs for the transport vehicle system.

[0006] Therefore, the present invention aims to provide an automated guided vehicle (AGV) system that allows the transport platform used for transport to be stored in a small space without the need for special equipment. [Means for solving the problem]

[0007] To solve the above-mentioned problems, the present invention provides an automated guided vehicle (AGV) system for transporting goods using a plurality of transport platforms that can be transported by an AGV, wherein each of the plurality of transport platforms has four legs, the outer width of two legs is smaller than the inner width between the other two legs, and is configured to be stackable in a nesting manner, the AGV system comprises an AGV equipped with a vertically movable lifting platform, a stacking station equipped with a support base for stacking and placing the transport platforms, and a controller for controlling the AGV so that the plurality of transport platforms are stacked on the stacking station, the controller providing (A) step A to move the AGV carrying the first transport platform of the plurality of transport platforms in a first direction so as to slide under the second transport platform placed on the support base of the stacking station, (B) step B to raise the lifting platform of the AGV and lift the first transport platform and the second transport platform, and (C) The system is characterized by being configured to perform the following steps: (D) raising the lifting platform and moving the automated guided vehicle in a first direction to move each leg of the first transport platform to a position where it can be placed on the support base of the stacking station; (E) lowering the lifting platform and placing each leg of the first transport platform on the support base of the stacking station; and (E) moving the automated guided vehicle to move it away from under the first transport platform.

[0008] According to the present invention configured in this way, a controller can cause an automated guided vehicle (AGV) to perform a series of operations, allowing multiple transport platforms to be stacked without the use of special equipment. This reduces the cost of the AGV system, while also reducing the space required to store the transport platforms, thereby achieving space savings.

[0009] In the present invention, preferably, the support base of the stacking station comprises a mounting surface that supports each leg of the first transport mounting base, and a first guide surface formed to be continuous with the mounting surface, wherein the first guide surface is inclined to be higher from the mounting surface in a first direction.

[0010] In the present invention configured as described above, in step D, when placing each leg of the first transport platform onto the support base of the stacking station, the first transport platform is lowered so that a portion of the lower end surface of each leg rests on the inclined first guide surface. As a result, each leg slides down on the first guide surface, and finally the lower end surface of each leg is placed on the mounting surface connected to the first guide surface. Therefore, even if there is an error in the starting position of the lowering platform of the automated guided vehicle, the first transport platform can be placed in the correct position on the support base.

[0011] In the present invention, preferably, the support base of the stacking station comprises a mounting surface that supports each leg of the first transport mounting base, and a second guide surface formed to be continuous with the mounting surface, wherein the second guide surface is inclined to become higher toward the outside in the width direction of the first transport mounting base.

[0012] In the present invention configured as described above, when placing each leg of the first transport platform on the support base of the stacking station in step D, even if the position in which the first transport platform is lowered is shifted in the width direction, the lower end surfaces of the legs of the first transport platform are guided by the second guide surface and placed on the platform. This makes it possible to place the first transport platform in the correct position on the support base.

[0013] In the present invention, preferably, the support base of the stacking station has a mounting surface that supports each leg of the first transport platform, and an auxiliary support surface provided above the mounting surface so as to be located below each leg of the second transport platform when each leg of the first transport platform is supported on the mounting surface.

[0014] According to the present invention configured in this way, since the support base of the stacking station has an auxiliary support surface provided above the mounting surface, even if multiple stacked transport platforms placed on the mounting surface become unstable, each leg of the second transport platform is supported by the auxiliary support surface, so that multiple transport platforms can be placed stably.

[0015] In the present invention, preferably, the stacking station is equipped with a wheel stopper, which is positioned to contact the wheel of the automated guided vehicle when, in step C, each leg of the first transport platform is moved to a position where it can be placed on the support base of the stacking station.

[0016] According to the present invention configured in this way, since the stacking station is equipped with wheel stoppers, the controller can move the automated guided vehicle (AGV) to a position where the wheels contact the wheel stoppers, thereby stopping the AGV in the correct position and placing the transport platform in the correct position on the support platform.

[0017] In the present invention, preferably, the stacking station is equipped with wheel guides that contact the wheels of the automated guided vehicle (AGV) and guide the AGV, and these wheel guides the AGV's travel path in step A from the left and right directions.

[0018] According to the present invention configured in this way, the stacking station is equipped with wheel guides that contact the wheels of the automated guided vehicle (AGV) to guide the AGV, so that the AGV's travel path can be guided from the left and right directions, and the transport platform can be placed in the correct position on the support platform.

[0019] In the present invention, preferably, the stacking station includes a vehicle body guide that abuts against the vehicle body of the automated guided vehicle (AGV) to guide the AGV. This vehicle body guide is formed at a height that does not interfere with the legs of the first transport carrier being transported by the AGV, and guides the travel path of the AGV in the left - right direction in step A.

[0020] According to the present invention configured as described above, since the stacking station includes a vehicle body guide that abuts against the vehicle body of the AGV to guide the AGV, the travel path of the AGV can be guided from the left - right direction, and the transport carrier can be placed at the accurate position of the support table.

Advantages of the Invention

[0021] According to the AGV system of the present invention, without using a special device, the transport carrier used for transportation can be stored in a small space.

Brief Description of the Drawings

[0022] [Figure 1] It is a diagram showing the entire AGV system according to the first embodiment of the present invention. [Figure 2] It is a perspective view of the AGV provided in the AGV system according to the first embodiment of the present invention. [Figure 3] It is a perspective view showing the transport carrier provided in the AGV system according to the first embodiment of the present invention. [Figure 4] It is a perspective view showing a state where a plurality of transport carriers are stacked on the stacking station in the AGV system according to the first embodiment of the present invention. [Figure 5] It is a perspective view showing the stacking station provided in the AGV system according to the first embodiment of the present invention. [Figure 6] It is a diagram showing the procedure for stacking a plurality of transport carriers on the stacking station in the AGV system according to the first embodiment of the present invention. [Figure 7]This figure shows the procedure for stacking multiple transport and mounting platforms on a stacking station in an automated guided vehicle system according to the first embodiment of the present invention. [Figure 8] This figure shows the procedure for stacking multiple transport and mounting platforms on a stacking station in an automated guided vehicle system according to the first embodiment of the present invention. [Figure 9] This figure shows the procedure for stacking multiple transport and mounting platforms on a stacking station in an automated guided vehicle system according to the first embodiment of the present invention. [Figure 10] This figure shows the procedure for stacking multiple transport and mounting platforms on a stacking station in an automated guided vehicle system according to the first embodiment of the present invention. [Figure 11] This figure shows the procedure for stacking multiple transport and mounting platforms on a stacking station in an automated guided vehicle system according to the first embodiment of the present invention. [Figure 12] This figure shows the procedure for stacking multiple transport and mounting platforms on a stacking station in an automated guided vehicle system according to the first embodiment of the present invention. [Figure 13] This is a perspective view showing a stacking station provided in an automated guided vehicle system according to a second embodiment of the present invention. [Figure 14] This figure shows the operation of an automated guided vehicle system according to a second embodiment of the present invention. [Figure 15] This figure shows an enlarged view of a stacking station with multiple transport platforms mounted on it, in an automated guided vehicle system according to a second embodiment of the present invention. [Modes for carrying out the invention]

[0023] Next, an automated guided vehicle system according to an embodiment of the present invention will be described with reference to the attached drawings. Figure 1 is a diagram showing the entire automated guided vehicle (AGV) system according to the first embodiment of the present invention. Figure 2 is a perspective view of the AGV provided in the AGV system according to the first embodiment of the present invention. Figure 3 is a perspective view showing the transport platform provided in the AGV system according to the first embodiment of the present invention. Figure 4 is a perspective view showing multiple transport platforms provided in the AGV system according to the first embodiment of the present invention stacked on a stacking station. Figure 5 is a perspective view showing the stacking station provided in the AGV system according to the first embodiment of the present invention.

[0024] As shown in Figure 1, the automated guided vehicle (AGV) system 1 according to the first embodiment of the present invention comprises an AGV 2, a plurality of transport and loading platforms 4, a stacking station 6 for stacking and loading the transport and loading platforms 4, and a controller 8 for controlling the AGV 2. In the AGV system 1 of this embodiment, cargo (not shown) is loaded onto the transport and loading platforms 4, the AGV 2 moves under the transport and loading platforms 4, and lifts the transport and loading platforms 4 loaded with cargo. The AGV 2 is then driven to transport the transport and loading platforms 4 to the desired location. Unused transport and loading platforms 4 are stored stacked in the stacking station 6. Although Figure 1 shows one AGV 2 and one stacking station 6, the AGV system 1 usually has multiple AGVs 2, and two or more stacking stations 6 can be provided.

[0025] As shown in Figure 2, the automated guided vehicle (AGV) 2 has a body 2a, a lifting platform 2b provided on the upper surface of the body 2a, two drive wheels 2c, and four auxiliary wheels 2d. It is configured to be able to move under its own power based on command signals from the controller 8, using power from a battery (not shown) built into the body 2a.

[0026] The lifting platform 2b is provided on the upper surface of the vehicle body 2a and is configured to move up and down based on command signals from the controller 8. That is, when the lifting platform 2b is lowered, the automated guided vehicle 2 is at a height that allows it to get underneath the transport platform 4. Then, by raising the lifting platform 2b while the automated guided vehicle 2 is underneath the transport platform 4, the transport platform 4 is lifted (the legs of the transport platform 4 are lifted off the floor), making it possible to transport the transport platform 4 and the cargo (not shown) loaded on it. In addition, at the stacking station 6, by raising or lowering the lifting platform 2b at a predetermined timing, empty transport platforms 4 (transport platforms 4 without cargo loaded on them) can be stacked.

[0027] The drive wheels 2c are provided one on each side of the bottom of the vehicle body 2a (only one is shown in Figure 2) and are rotationally driven by a motor (not shown) built into the vehicle body 2a. By rotating these two drive wheels 2c in the same direction at the same rotational speed, the automated guided vehicle 2 can be moved forward or backward. Furthermore, by rotating each drive wheel 2c in opposite directions at the same rotational speed, the automated guided vehicle 2 can be turned in place.

[0028] The auxiliary wheels 2d are driven wheels, one in front of and one behind each of the drive wheels 2c, for a total of four (only two are shown in Figure 2). When the automated guided vehicle 2 is placed on the floor, the two drive wheels 2c and the four auxiliary wheels 2d are in contact with the floor, and the lifting platform 2b is maintained in a nearly horizontal position.

[0029] As shown in Figure 3, the transport platform 4 is a tower-shaped metal base equipped with four legs and configured to be transportable by an automated guided vehicle 2. The transport platform 4 consists of a top surface 4a for placing cargo and four legs extending downward from the four corners of the top surface 4a. In this embodiment, the top surface 4a is configured to have a roughly rectangular shape by combining metal beams in a grid pattern. In this embodiment, the top surface 4a is configured by combining beams in a grid pattern, but the top surface 4a can be formed in any size and shape using any material, such as a plate-shaped member.

[0030] The four legs extend vertically downward from the four corners of the top surface 4a. That is, the transport platform 4 has two front legs 4b provided at the front corners of the top surface 4a and two rear legs 4c provided at the rear corners. In this embodiment, the cross-sections of each front leg 4b and each rear leg 4c are all the same rectangle. The two rear legs 4c are attached so as to protrude from both sides of the top surface 4a. Therefore, the outer width W1 of the two front legs 4b is smaller than the inner width W2 between the two rear legs 4c. In other words, in this embodiment, the outer width W1 of the two front legs 4b is smaller than the outer width of the two rear legs 4c minus the thickness of two rear legs 4c. As a result, the two front legs 4b and top surface 4a of one transport platform 4 can pass between the two rear legs 4c of another transport platform 4. This allows the transport platforms 4 to be stacked in a nested manner, as shown in Figure 4.

[0031] In this embodiment, each leg is independent, but as a modification, the lower ends of the two front legs 4b and / or the lower ends of the front legs 4b and rear legs 4c on each side may be connected by a beam-like member or the like. Alternatively, the transport platform 4 may have four or more legs positioned so as not to interfere when stacked in a nested manner, and these legs may be connected to each other as appropriate.

[0032] Next, as shown in Figure 5, the stacking station 6 consists of four support columns, which are support bases provided on the floor surface F (the running surface of the automated guided vehicle 2) on which the automated guided vehicle system 1 is installed. Specifically, the stacking station 6 consists of two front support columns 6a positioned to align with each of the front legs 4b of the transport platform 4, and two rear support columns 6b positioned to align with each of the rear legs 4c. In other words, the positions of the four support columns of the stacking station 6 and the positions of the four legs of the transport platform 4 coincide in a plan view.

[0033] As a result, the lower end surface of each front leg portion 4b is supported by contacting the mounting surface 6c at the upper end of each front support column 6a, and the lower end surface of each rear leg portion 4c is supported by contacting the mounting surface 6c at the upper end of each rear support column 6b. In this embodiment, the front support columns 6a and rear support columns 6b are composed of rectangular columnar members fixed to the floor surface F, and their upper end surfaces each constitute the mounting surface 6c. In this embodiment, the cross-sectional shapes of the front support columns 6a and rear support columns 6b are the same as the cross-sectional shapes of the front leg portions 4b and rear leg portions 4c of the transport platform 4. Furthermore, in order to allow the unmanned transport vehicle 2 carrying the transport platform 4 to pass between the rear support columns 6b, the inner spacing W4 (same as the width W2 (Figure 3) in this embodiment) of the two rear support columns 6b is wider than the outer spacing W3 (same as the width W1 (Figure 3) in this embodiment) of the two front support columns 6a.

[0034] Furthermore, multiple transport platforms 4 can be stacked and placed on the stacking station 6, which consists of these front support columns 6a and rear support columns 6b (Figure 4 shows a state in which three transport platforms 4 are stacked). That is, when multiple transport platforms 4 are stacked and placed on the stacking station 6, the front legs 4b and rear legs 4c of the lowest transport platform 4 are supported by the front support columns 6a and rear support columns 6b, respectively. In this embodiment, the support base of the stacking station 6 is composed of four independent support columns, but the support base can be configured in any shape as long as it is in a form that allows the transport platforms 4 to be stacked and placed without obstructing the movement of the automated guided vehicle 2 or interfering with the legs of the transport platforms 4 during transport. For example, the front support columns 6a and rear support columns 6b on both sides of the support base can be integrated to form a rectangular parallelepiped shape, and the transport platform 4 can be supported by the pair of rectangular parallelepipeds on both sides, or an integrated support base can be constructed that can support each leg of the transport platform 4.

[0035] Furthermore, as shown in Figure 5, the stacking station 6 is provided with wheel stoppers 10. These wheel stoppers 10 are linearly extending members attached to the floor surface F inside the four support columns of the stacking station 6, and are oriented parallel to the line connecting the two front support columns 6a. As will be described later, with the automated guided vehicle (AGV) 2 lifting the transport platform 4, the AGV 2 moves forward to a position where its wheels (auxiliary wheels 2d) come into contact with the wheel stoppers 10. This aligns each leg (front legs 4b and rear legs 4c) of the transport platform 4 placed on the AGV 2 with the support base (front support columns 6a and rear support columns 6b) of the stacking station 6, allowing the transport platform 4 to be placed on the support base. In this embodiment, the stacking station 6 is provided with wheel stoppers 10, but the wheel stoppers 10 can be omitted. In this case, the AGV 2 is stopped at the appropriate position by position control by the controller 8.

[0036] Furthermore, the stacking station 6 is provided with wheel guides 12. These wheel guides 12 are a pair of rail-shaped members attached to the floor surface F so as to extend from the outside to the inside of the four support columns of the stacking station 6. The pair of wheel guides 12 extend parallel to each other in the area inside the four support columns and are configured to guide the travel path of the automated guided vehicle (AGV) 2 as it enters the stacking station 6. That is, when the AGV 2 travels between the pair of wheel guides 12, the wheels on both sides of the AGV 2 (drive wheels 2c and auxiliary wheels 2d) come into contact with each wheel guide 12, respectively, guiding the path that the AGV 2 travels. As a result, the AGV 2 can easily travel along the correct path connecting the center between the two rear support columns 6b and the center between the two front support columns 6a.

[0037] Furthermore, the pair of wheel guides 12, which extend parallel to each other inside the four support columns of the stacking station 6, are widened in a trumpet shape at the end on the rear support column 6b side into which the automated guided vehicle (AGV) 2 enters. This allows the AGV 2 entering the stacking station 6 to easily position itself between the two wheel guides 12, and its travel path is guided by the wheel guides 12. In this embodiment, the stacking station 6 is provided with wheel guides 12, but the wheel guides 12 can be omitted. In this case, the controller 8 controls the AGV 2 to travel along an appropriate path.

[0038] Alternatively, as a modification, the stacking station 6 may be equipped with a body guide (not shown) instead of the wheel guide 12. The wheel guide 12 described above contacts the wheels (drive wheels 2c and auxiliary wheels 2d) of the automated guided vehicle 2 and guides the travel path of the automated guided vehicle 2 from the left and right directions. In contrast, the body guide (not shown) contacts both sides of the body 2a of the automated guided vehicle 2 and guides the travel path of the automated guided vehicle 2 from the left and right directions. It is preferable that this body guide (not shown) be formed at a low position near the lower end of the body 2a, or at a height that does not interfere with the legs (front legs 4b and rear legs 4c) of the transport platform 4 being transported by the automated guided vehicle 2.

[0039] Next, the controller 8 is configured to transmit command signals to the automated guided vehicles (AGVs) 2, thereby causing the AGVs 2 to move and raising and lowering their lifting platforms 2b. Specifically, the controller 8 consists of a transceiver, a microprocessor, memory, an interface circuit, and software (not shown) to operate these components. As a result, the controller 8 can control each AGV 2 to move the transport platform 4, on which the cargo (not shown) is loaded, to a desired location and transport the cargo. Furthermore, the controller 8 can control the AGVs 2 so that multiple transport platforms 4 are stacked on the stacking station 6 by performing a predetermined procedure described later.

[0040] Next, the operation of the automated guided vehicle system 1 according to an embodiment of the present invention will be described with reference to Figures 6 to 12. Figures 6 to 12 show the procedure for stacking multiple transport platforms 4 on a stacking station 6 in an automated guided vehicle system 1 according to an embodiment of the present invention. Note that the wheel guides 12 of the stacking station 6 are omitted from the illustration in Figures 6 to 12.

[0041] First, as shown in Figure 6, the controller 8 transmits a command signal to move the automated guided vehicle (AGV) 2 under the empty transport platform 4 placed on the floor F. In this state, by raising the lifting platform 2b by a predetermined distance, the transport platform 4 is lifted, and the lower end surfaces of each leg of the transport platform 4 are lifted off the floor F. Furthermore, as step A, as shown in Figure 7, with the transport platform 4 (first transport platform) on it, the AGV 2 is moved so as to slide under the transport platform 4 (second transport platform) placed on the support base (front support column 6a and rear support column 6b) of the stacking station 6. Here, the AGV 2 travels in a direction where the narrowly spaced front legs 4b of the transport platform 4 (first transport platform) on which it is placed are forward, and the widely spaced rear legs 4c are backward. At this time, the travel path of the AGV 2 is guided from the left and right by the wheel guide 12 (Figure 5). Therefore, the automated guided vehicle 2 can easily slip under the transport platform 4 placed on the stacking station 6 by following a suitable path that passes through the center of the two rear support columns 6b of the stacking station 6. That is, the transport platform 4 (first transport platform) placed on the automated guided vehicle 2 moves from between the widely spaced rear legs 4c of the transport platform 4 placed on the stacking station 6 towards the narrowly spaced front legs 4b.

[0042] In the state shown in Figure 7, the height H1 of the upper edge of the top surface 4a of the transport platform 4 (first transport platform) placed on the automated guided vehicle 2 is lower than the height H2 of the lower edge of the top surface 4a of the transport platform 4 (second transport platform) placed on the stacking station 6. In other words, the lifting platform 2b of the automated guided vehicle 2 lifts the transport platform 4 by a distance smaller than the length obtained by subtracting the thickness of the top surface 4a of the transport platform 4 from the height of the front support columns 6a and rear support columns 6b. As a result, the automated guided vehicle 2 with the transport platform 4 on it can be moved under the transport platform 4 (second transport platform) placed on the stacking station 6.

[0043] Then, as shown in Figure 8, the controller 8 moves the automated guided vehicle 2 to a position where each rear leg 4c of the transport platform 4 (first transport platform) mounted on the automated guided vehicle 2 is adjacent to each rear support column 6b of the stacking station 6, and then stops it.

[0044] Next, as shown in Figure 9, the controller 8 raises the lifting platform 2b of the automated guided vehicle 2 as step B. As a result, the transport platform 4 (second transport platform) that was placed on the stacking station 6 is lifted and placed on the top surface 4a of the transport platform 4 (first transport platform) that has been raised by the lifting platform 2b. In addition, by raising the lifting platform 2b, the lower ends of each leg (front leg 4b and rear leg 4c) of the transport platform 4 placed on the lifting platform 2b become higher than the upper ends of the support base (front support column 6a and rear support column 6b) of the stacking station 6. In other words, the lifting platform 2b of the automated guided vehicle 2 raises the transport platform 4 by a distance longer than the height of the front support column 6a and rear support column 6b. In Figures 8 and 9, there is only one transport platform 4 (second transport platform) placed on the stacking station 6. However, if multiple transport platforms 4 are stacked on the stacking station 6, all of the transport platforms 4 will be lifted simultaneously.

[0045] Furthermore, as shown in Figure 10, in step C, the controller 8 moves the automated guided vehicle 2 forward (traveling in the first direction) while keeping the lifting platform 2b raised, moving the front legs 4b and rear legs 4c of the transport platform 4 (first transport platform) placed on the lifting platform 2b to a position where they align with the front support columns 6a and rear support columns 6b of the stacking station 6, respectively. As a result, each leg of the transport platform 4 (front legs 4b and rear legs 4c) is moved to a position where it can be placed on the support base (front support columns 6a and rear support columns 6b) of the stacking station 6. In this state, the wheel stopper 10 provided on the stacking station 6 and the wheels (auxiliary wheels 2d) of the automated guided vehicle 2 come into contact. In other words, when each leg (front leg 4b and rear leg 4c) of the transport platform 4 (first transport platform) being transported is moved to a position where it can be placed on the support base (front support column 6a and rear support column 6b) of the stacking station 6, the wheels of the automated guided vehicle 2 come into contact with the wheel stopper 10. This makes it easy to move the automated guided vehicle 2 forward to the appropriate position.

[0046] Next, as shown in Figure 11, in step D, the controller 8 lowers the lifting platform 2b of the automated guided vehicle 2, and places each leg (front leg 4b and rear leg 4c) of the transport platform 4 (first transport platform) that is placed on the lifting platform 2b onto the support base (front support column 6a and rear support column 6b) of the stacking station 6. That is, when the lifting platform 2b is lowered, the lower end surfaces of the front leg 4b and rear leg 4c of the transport platform 4 come into contact with the upper end surfaces of the front support column 6a and rear support column 6b of the stacking station 6. Then, when the lifting platform 2b is lowered further, the transport platform 4 (first transport platform) that is placed on the lifting platform 2b is placed on the support base of the stacking station 6, and the upper surface of the lifting platform 2b separates from the lower surface of the top surface 4a of the transport platform 4.

[0047] Finally, as shown in Figure 12, the controller 8, in step E, moves the automated guided vehicle (AGV) 2 and moves it away from under the transport platform 4 (first transport platform). In Figure 12, the AGV 2 is moved away from under the transport platform 4 by moving it backward, but if the wheel stopper 10 is not provided, the AGV 2 can also be moved away by moving it forward. Alternatively, if the wheel stopper 10 and wheel guide 12 are not provided, the AGV 2 can be rotated in place under the transport platform 4 and moved away from the side of the transport platform 4. By repeating the procedure in Figures 6 to 12, three or more transport platforms 4 can be stacked and placed on the stacking station 6.

[0048] On the other hand, when removing one transport platform 4 from multiple transport platforms 4 stacked on the stacking station 6 (unstacking), the procedure shown in Figures 6 to 12 is performed in reverse order. That is, first, the automated guided vehicle (AGV) 2 is moved under the transport platforms 4 stacked on the stacking station 6. In this state, the lifting platform 2b of the AGV 2 is raised to lift the multiple transport platforms 4 that are stacked. Next, the AGV 2 is moved backward so that the legs (front legs 4b and rear legs 4c) of the transport platform 4 that is stacked second from the bottom are aligned with the support base (front support column 6a and rear support column 6b) of the stacking station 6. In this state, the lifting platform 2b of the AGV 2 is lowered to place the transport platform 4 that is stacked second from the bottom onto the support base of the stacking station 6. In this state, the upper surface of the top surface 4a of the lowest transport platform 4 is separated from the lower surface of the top surface 4a of the second lowest transport platform 4, so by moving the automated guided vehicle 2 out of the way, only the transport platform 4 that was stacked at the bottom can be removed.

[0049] According to the first embodiment of the present invention, the automated guided vehicle system 1 allows multiple transport platforms 4 to be stacked without the use of special equipment by having the controller 8 cause the automated guided vehicle 2 to perform a series of operations shown in Figures 6 to 12. This reduces the space required to store the transport platforms 4 while keeping the cost of the automated guided vehicle system 1 down, thereby achieving space savings.

[0050] Furthermore, according to the automated guided vehicle system 1 of this embodiment, since the stacking station 6 is equipped with wheel stoppers 10, the controller 8 can move the automated guided vehicle 2 to a position where the wheels (auxiliary wheels 2d) come into contact with the wheel stoppers 10, thereby stopping the automated guided vehicle 2 at the correct position (Figure 10), and the transport platform 4 can be placed at the correct position on the support base (front support column 6a and rear support column 6b).

[0051] Furthermore, according to the automated guided vehicle system 1 of this embodiment, the stacking station 6 is equipped with wheel guides 12 that contact the wheels (drive wheels 2c and auxiliary wheels 2d) of the automated guided vehicle 2 to guide the automated guided vehicle 2. This allows the travel path of the automated guided vehicle 2 to be guided from the left and right directions, and the transport platform 4 can be placed in the precise position on the support base (front support column 6a and rear support column 6b).

[0052] Next, an automated guided vehicle system according to a second embodiment of the present invention will be described with reference to Figures 13 to 15. The automated guided vehicle (AGV) system according to this embodiment differs from the first embodiment described above in the structure of the stacking station. Therefore, below, only the differences between the second embodiment of the present invention and the first embodiment will be described, and similar configurations, operations, and effects will not be explained. Figure 13 is a perspective view showing a stacking station provided in the AGV system according to the second embodiment of the present invention. Figure 14 is a diagram showing the operation of the AGV system according to the second embodiment of the present invention, and is a magnified view of the stacking column of the stacking station. Figure 15 is a magnified view of the stacking column of a stacking station on which multiple transport platforms are placed in the AGV system according to the second embodiment of the present invention.

[0053] As shown in Figure 13, the stacking station 16 provided in the automated guided vehicle system according to the second embodiment of the present invention consists of four support columns, which are support bases provided on the floor surface F (the running surface of the automated guided vehicle 2) on which the automated guided vehicle system is installed. Specifically, the stacking station 16 consists of two front support columns 16a provided at positions that align with each front leg portion 4b of the transport platform 4, and two rear support columns 16b provided at positions that align with each rear leg portion 4c.

[0054] As a result, the lower end surfaces of each front leg 4b of the transport platform 4 are supported by contacting the mounting surface 18 of each front support column 16a, and the lower end surfaces of each rear leg 4c are supported by contacting the mounting surface 18 of each rear support column 16b. In this embodiment, the front support columns 16a and rear support columns 16b are composed of stepped members fixed to the floor surface F, and the lowest step of these steps constitutes the mounting surface 18. In this embodiment, the mounting surfaces 18 of the front support columns 16a and rear support columns 6b are oriented horizontally, and their shapes are the same as the shapes of the lower end surfaces of the front leg 4b and rear leg 4c of the transport platform 4. Furthermore, in this embodiment as well, the inner spacing W4 between the two rear support columns 16b is wider than the outer spacing W3 between the two front support columns 6a so that the unmanned transport vehicle 2 carrying the transport platform 4 can pass between the rear support columns 16b.

[0055] Furthermore, the front support column 16a and the rear support column 16b are each provided with a first guide surface 18a formed to be continuous with the mounting surface 18. These first guide surfaces 18a are inclined to rise towards the back of the stairs, continuous with the horizontally oriented mounting surface 18. That is, the first guide surface 18a is a plane that is inclined to rise in the direction in which the automated guided vehicle 2 moves (first direction) in step C (Figure 10) described above. Also, the first guide surface 18a may be provided on both the front support column 16a and the rear support column 16b, or on only one of them.

[0056] Furthermore, the front support column 16a and the rear support column 16b are each provided with a second guide surface 18b formed to be continuous with the mounting surface 18. These second guide surfaces 18b are inclined to be higher toward the outside in the width direction of the transport platform 4 on which the transport platform 4 is placed, so as to be continuous with the horizontally oriented mounting surface 18. That is, the second guide surface 18b is inclined in a direction perpendicular to the direction in which the automated guided vehicle 2 moves (first direction) in step C (Figure 10) described above, and is a plane that is inclined to be higher toward the outside in the width direction of the stacking station 16. Also, the second guide surface 18b may be provided on both the front support column 16a and the rear support column 16b, or on only one of them.

[0057] Furthermore, the front support column 16a and the rear support column 16b are each provided with a first auxiliary support surface 20a and a second auxiliary support surface 20b, respectively, which are located above the mounting surface 18. The first auxiliary support surface 20a is a horizontal surface located at a higher position than the mounting surface 18, and the second auxiliary support surface 20b is a horizontal surface located at a higher position than the first auxiliary support surface 20a. In other words, in this embodiment, the front support column 16a and the rear support column 16b are configured in a stepped manner, comprising the mounting surface 18, the first auxiliary support surface 20a, and the second auxiliary support surface 20b.

[0058] Therefore, when multiple transport platforms 4 are placed on the stacking station 6, each leg of the bottommost transport platform 4 is placed on each of the placement surfaces 18, each leg of the second-to-last transport platform 4 is located on each of the first auxiliary support surfaces 20a, and each leg of the third-to-last transport platform 4 is located on each of the second auxiliary support surfaces 20b. In this embodiment, auxiliary support surfaces are provided in two layers each on the front support column 16a and the rear support column 16b, but they may be provided on only one of the front support column 16a or the rear support column 16b. Also, there may be only one layer of auxiliary support surfaces, or there may be three or more layers.

[0059] Next, the operation of the automated guided vehicle system according to the second embodiment of the present invention will be described with reference to Figures 14 and 15. First, step A (Figure 7), in which the automated guided vehicle 2, carrying the transport platform 4 (first transport platform), is moved so as to slide under the transport platform 4 (second transport platform) placed on the support base (front support column 16a and rear support column 16b) of the stacking station 16, is the same as in the first embodiment described above. Then, the procedure (Figure 8) in which the automated guided vehicle 2 is driven to a position where each rear leg portion 4c of the transport platform 4 (first transport platform) on the automated guided vehicle 2 is adjacent to each rear support column 6b of the stacking station 6, and then stopped, is also the same as in the first embodiment described above.

[0060] Furthermore, step B (Figure 9), which involves raising the lifting platform 2b of the automated guided vehicle 2 and lifting the transport platform 4 (first transport platform) placed on the transport platform 4 (first transport platform) and the transport platform 4 (second transport platform) placed on the support base (front support column 16a and rear support column 16b), is the same as in the first embodiment described above.

[0061] Next, in the first embodiment described above, the automated guided vehicle 2 was advanced so that each leg (front leg 4b and rear leg 4c) of the transport platform 4 (first transport platform) mounted on the automated guided vehicle 2 was positioned directly above the mounting surface 6c of the support base (front support column 6a and mounting surface 6c) (Figure 10: Step C). In contrast, in this embodiment, as Step C, the automated guided vehicle 2 is advanced so that each rear leg 4c of the transport platform 4 is moved slightly further back than directly above the mounting surface 18 of the rear support column 16b, as shown by the dashed line in Figure 14.

[0062] As a result, as shown in Figure 14, the front ends of each rear leg portion 4c of the transport platform 4 are positioned above the first guide surface 18a formed on the rear side of the mounting surface 18 of the rear support column 16b. Although Figure 14 shows the positional relationship between the rear leg portions 4c and the rear support column 16b of the transport platform 4, similarly for the front leg portions 4b, the front ends of the front leg portions 4b are positioned above the first guide surface 18a on the rear side of the mounting surface 18 of the front support column 16a.

[0063] Next, in step D, when the lifting platform 2b of the automated guided vehicle 2 is lowered, the front corners of each rear leg 4c of the transport platform 4 (the corners between the front and lower ends of the rear leg 4c) come into contact with the first guide surface 18a provided on the rear side of the mounting surface 18 of the rear support column 16b. That is, when each leg (front leg 4b and rear leg 4c) of the transport platform 4 is placed on the support base of the stacking station 16, the transport platform 4 is lowered so that a part of the lower end surface of each leg comes into contact with the inclined first guide surface 18a.

[0064] Here, the first guide surface 18a is an inclined plane formed to be continuous with the mounting surface 18, and is configured to be higher toward the rear (forward of the automated guided vehicle 2: the first direction). Therefore, each rear leg portion 4c that comes into contact with the first guide surface 18a slides along the first guide surface 18a as the lifting platform 2b descends, and moves toward the rear (left in Figure 14). The lower end surface of each rear leg portion 4c is then placed on the mounting surface 18 that is continuous with the first guide surface 18a, as shown by the dashed line in Figure 14. That is, each rear leg portion 4c of the transport mounting platform 4 is placed on the rear support column 16b such that its front end is located on the boundary line between the mounting surface 18 and the first guide surface 18a. Similarly, each front leg portion 4b slides against the first guide surface 18a provided on the front support column 16a and is placed on the mounting surface 18 of the front support column 16a.

[0065] Thus, in this embodiment, each leg (front leg 4b and rear leg 4c) of the transport platform 4 (first transport platform) lowered by the lifting platform 2b slides along the first guide surface 18a and is placed on the mounting surface 18 connected to the first guide surface 18a. Therefore, even if there is variation in the positioning of the rear leg 4c, shown by the dashed line in Figure 14, in step C, the position where the transport platform 4 is placed on the mounting surface 18 is defined by the boundary line between the first guide surface 18a and the mounting surface 18. As a result, the transport platform 4 can be placed in an accurate position on the support base (front support column 16a and rear support column 16b).

[0066] Furthermore, in step D, when the lifting platform 2b of the automated guided vehicle 2 is lowered, if the transport platform 4 placed on the lifting platform 2b is misaligned in the width direction (lateral direction of the automated guided vehicle 2), the lower ends of the legs (front legs 4b and rear legs 4c) of the transport platform 4 will come into contact with the second guide surface 18b (Figure 13). As a result, as the lifting platform 2b is lowered, the transport platform 4 is guided in the width direction by the second guide surface 18b, and the transport platform 4 is placed in the correct position.

[0067] After the stacked transport and mounting platforms 4 are placed on the support bases (front support columns 16a and rear support columns 16b) of the stacking station 16 in step D, the procedure for moving the automated guided vehicle 2 to move it away from under the transport and mounting platforms 4 in step E is the same as in the first embodiment described above.

[0068] Furthermore, as shown in Figure 15, in this embodiment, when multiple transport platforms 4 are stacked and placed on the stacking station 16, the rear leg portion 4c-1 of the lowest-stacked transport platform 4 is placed on the mounting surface 18 of the rear support column 16b. Also, the rear leg portion 4c-2 of the second-to-last stacked transport platform 4 is located above the first auxiliary support surface 20a provided on the rear side of each mounting surface 18. In this embodiment, the height difference between the mounting surface 18 and the first auxiliary support surface 20a is slightly less than the thickness of the top surface 4a, so there is a small gap between the first auxiliary support surface 20a and the rear leg portion 4c-2. In addition, the rear leg portion 4c-3 of the third-to-last transport platform 4 is located above the second auxiliary support surface 20b provided on the rear side of each mounting surface 18, with a small gap between them.

[0069] Similarly, with respect to the front legs 4b placed on the front support column 16a, the lowest stacked front leg 4b of the transport platform 4 is placed on the mounting surface 18, the second front leg 4b of the transport platform 4 is positioned above the first auxiliary support surface 20a, and the third front leg 4b of the transport platform 4 is positioned above the second auxiliary support surface 20b (the above are not shown).

[0070] In this configuration, if the multiple transport platforms 4 stacked on the stacking station 16 tilt forward due to vibration or other reasons, the legs located above the first auxiliary support surface 20a and the second auxiliary support surface 20b will contact each auxiliary support surface, thereby supporting the stacked transport platforms 4. As a result, multiple transport platforms 4 can be stably stacked on the stacking station 16. In this embodiment, a small gap is provided between each auxiliary support surface and the lower end of the corresponding leg, but the auxiliary support surfaces can also be configured so that each auxiliary support surface contacts the lower end of the corresponding leg.

[0071] According to the automated guided vehicle system of the second embodiment of the present invention, in step D, when placing each leg (front leg 4b and rear leg 4c) of the transport platform 4 (first transport platform) onto the support base (front support column 16a and rear support column 16b) of the stacking station 16, the transport platform 4 is lowered so that a part of the lower end surface of each leg rests on the inclined first guide surface 18a (dotted line in Figure 14). As a result, each leg slides down on the first guide surface 18a, and finally the lower end surface of each leg is placed on the mounting surface 18 connected to the first guide surface 18a (double-dotted line in Figure 14). Therefore, even if there is an error in the position where the lifting platform 2b of the automated guided vehicle 2 begins to lower, the transport platform 4 can be placed on the support base in the correct position.

[0072] Furthermore, according to the automated guided vehicle system of this embodiment, in step D, when each leg (front leg 4b and rear leg 4c) of the transport platform 4 (first transport platform) is placed on the support base (front support column 16a and rear support column 16b) of the stacking station 16, even if the position in which the transport platform 4 is lowered is shifted in the width direction, the lower end surfaces of the legs of the transport platform 4 are guided by the second guide surface 18b (Figure 13) and placed on the placement surface 18. This makes it possible to place the transport platform 4 in the correct position on the support base.

[0073] Furthermore, according to the automated guided vehicle system of this embodiment, the support base (front support column 16a and rear support column 16b) of the stacking station 16 has auxiliary support surfaces (first auxiliary support surface 20a and second auxiliary support surface 20b) provided above the mounting surface 18 (Figure 15). Therefore, even if the multiple stacked transport platforms 4 placed on the mounting surface 18 become unstable, the legs (front legs 4b and rear legs 4c) of the transport platforms 4 stacked on top are supported by the auxiliary support surfaces, allowing multiple transport platforms 4 to be placed stably.

[0074] Although embodiments of the present invention have been described above, various modifications can be made to the embodiments described above. In particular, the first embodiment described above is provided with a wheel stopper 10 and a wheel guide 12, and the second embodiment is provided with a first guide surface 18a, a second guide surface 18b, and auxiliary support surfaces (first auxiliary support surface 20a, second auxiliary support surface 20b). These components can be omitted as appropriate, and the present invention can also be constructed by appropriately selecting and combining the above components. [Explanation of Symbols]

[0075] 1. Automated Guided Vehicle System 2. Automated Guided Vehicles 2a Vehicle body 2b Elevator 2c drive wheel 2d training wheels 4. Transport and mounting platform 4a Top section 4b Front leg 4c Hind leg 6-tier stacking station 6a Front bundle pillar (support stand) 6b Back bundle pillar (support stand) 6c Mounting surface 8 controllers 10 Wheel stoppers 12 Wheel Guide 16-tier stacking station 16a Front bundle pillar (support stand) 16b Rear bundle pillar (support stand) 18 Mounting surface 18a First guide surface 18b Second guide surface 20a First auxiliary support surface 20b Second auxiliary support surface

Claims

1. An automated guided vehicle (AGV) system for transporting goods using multiple transport platforms that can be transported by an AGV, wherein each of the multiple transport platforms has four legs, and the outer width of two legs is smaller than the inner width between the other two legs, and is configured to be stackable in a nesting manner. The above automated guided vehicle system is An automated guided vehicle equipped with a platform that can move up and down, A stacking station equipped with a support base for stacking and placing transport and mounting platforms, This stacking station has a controller that controls the automated guided vehicle so that the multiple transport and mounting platforms described above are stacked on top of it. The above controller is (A) Step A, in which the automated guided vehicle, on which the first transport platform of the above-mentioned plurality of transport platforms is placed, is moved in a first direction so as to slide under the second transport platform placed on the support base of the stacking station, (B) Step B involves raising the lifting platform of the automated guided vehicle and lifting the first transport platform and the second transport platform, (C) Step C, in which the automated guided vehicle is driven in the first direction while the lifting platform is raised, and each leg of the first transport platform is moved to a position where it can be placed on the support base of the stacking station, (D) Step D, in which the lifting platform is lowered and each leg of the first transport platform is placed on the support base of the stacking station, (E) Step E involves moving the above-mentioned automated guided vehicle and moving it away from under the first transport platform, An automated guided vehicle system characterized by being configured to perform the following actions.

2. The automated guided vehicle system according to claim 1, wherein the support base of the stacking station comprises a mounting surface that supports each leg of the first transport mounting base, and a first guide surface formed to be connected to the mounting surface, and the first guide surface is inclined to be higher from the mounting surface toward the first direction.

3. The automated guided vehicle system according to claim 1, wherein the support base of the stacking station comprises a mounting surface that supports each leg of the first transport mounting base, and a second guide surface formed to be continuous with the mounting surface, the second guide surface being inclined to become higher toward the outside in the width direction of the first transport mounting base.

4. The automated guided vehicle system according to claim 1, wherein the support base of the stacking station has a mounting surface that supports each leg of the first transport mounting base, and an auxiliary support surface provided above the mounting surface so as to be located below each leg of the second transport mounting base when each leg of the first transport mounting base is supported on the mounting surface.

5. The automated guided vehicle system according to claim 1, wherein the stacking station is equipped with wheel stoppers, and the wheel stoppers are positioned so as to come into contact with the wheels of the automated guided vehicle when, in step C, each leg of the first transport platform is moved to a position on the support base of the stacking station.

6. The above stacking station is equipped with wheel guides that contact the wheels of the above automated guided vehicle and guide the above automated guided vehicle, and the wheel guides the travel path of the above automated guided vehicle in step A from the left and right directions, as described in claim 1 of the automated guided vehicle system.

7. The above stacking station is equipped with a body guide that contacts the body of the automated guided vehicle and guides the automated guided vehicle, and the body guide is formed at a height that does not interfere with the legs of the first transport platform being transported by the automated guided vehicle, and guides the travel path of the automated guided vehicle in step A from the left and right directions, as described in claim 1.

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