JP7502784B2 - Pallet extraction method, pallet extraction device, and pallet exchange device - Google Patents

Description

This invention relates to a pallet extraction method for extracting only a pallet from a loaded pallet and lowering the load onto a specified surface, a pallet extraction device used to carry out the method, and a pallet exchange device used to extract only a pallet from a loaded pallet and exchange it for another pallet.

In factories and warehouses, loaded pallets are usually transported by forklift and loaded onto truck beds or containers, or stored in warehouses. Each business owns its own pallets, and when a pallet loaded with goods is handed over to another business, that business transfers the goods onto its own pallet and returns the pallet to the original business.

Pallets also come in a variety of shapes and materials, including wood and synthetic resin. For example, when storing cargo, the cargo may be transferred from a wooden pallet to a synthetic resin pallet.

The applicant recently proposed a pallet removal device that can perform pallet replacement work mechanically, without relying on human power (see, for example, Patent Document 1).

FIG. 18 shows the pallet replacement operation performed by this pallet extractor.
First, a pallet A loaded with load C is introduced by a forklift onto a moving table 301 located in an area P1 where the pallet exchange work is carried out (hereinafter referred to as the "work area"). Load C shown in the figure is a stack of multiple cardboard boxes 300 arranged in multiple rows and columns.

Next, the operation of removing pallet A begins, and the moving table 301 is moved from the working area P1 to the area P2 where the pallet recovery operation is carried out (hereinafter referred to as the "pallet recovery area"). During this transfer, load C hits the first load restriction plate 302 and is left behind in the working area P1, and as a result only pallet A is removed. Following the movement of the moving table 301, the load receiving plate 303 is moved from the standby position Q to the working area P1, and the left-behind load C is received onto the load receiving plate 303.

Next, the process moves to the removal of the load receiving plate 303, which is returned from the working section P1 to the standby position Q. At this time, load C hits the second load restriction plate 304 and is left behind in the working section P1, and the load receiving plate 303 is removed. Another pallet (not shown) supported by a forklift is positioned directly below the load C that is being left behind, and load C is lowered onto the pallet and supported, completing the pallet replacement process.

Patent No. 3582834

In the above pallet removal process, the bottom of the cardboard box 300 is formed by folding the flaps 306 from all sides, as shown in Figure 19. Therefore, when the moving table 301 moves as shown by the dashed line in Figure 18, particularly in the case of pallet A, which has a non-slip surface, the surface of pallet A will rub against and soil the bottom of the cardboard box 300, and the flap 306 will be turned up as the butt joints 307 of the flaps 306 get caught, which may damage the bottom of the cardboard box 300.

The same applies if cargo C is made of a soft material such as fabric. When the moving table 301 moves, the bottom of cargo C may be rubbed against the surface of the pallet A, which may cause the bottom of cargo C to be damaged or soiled.

This invention was made in response to the above problem, and aims to provide a pallet extraction method, pallet extraction device, and pallet exchange device that do not risk damaging or soiling the bottom surface of the load.

The pallet removal method according to the present invention is a method for removing only the pallet from a loaded pallet and lowering the load onto a predetermined surface, and includes the steps of placing the loaded pallet on a moving table and positioning first and second load restriction plates on both sides of the load to restrict the passage of the load, tilting the moving table so that the top surface of the pallet is lower on the side of the second load restriction plate, removing the pallet by passing the moving table under the first load restriction plate while inclined, receiving the load that hits the first load restriction plate and is left behind with a load receiving plate that is following the moving table, and removing the load receiving plate by passing it under the second load restriction plate, and lowering the load that hits the second load restriction plate and is left behind on the predetermined surface.

According to this invention, when the pallet on the moving table is tilted to remove the pallet, the load is displaced downward along the first and second load control plates, but when it is lowered, the top surface of the pallet and the bottom surface of the load are not in surface contact, but only one side edge is in contact. When the moving table is moved in this state, the top surface of the pallet does not rub against the bottom surface of the load, and the bottom surface of the load is not damaged or soiled.

In one embodiment, the load is made up of multiple packed cardboard boxes arranged in multiple rows and columns for each tier, with the bottom of each cardboard box being formed by folding flaps on all four sides.

In this embodiment, there is no risk of the bottom of the cardboard box being rubbed against the top surface of the pallet and the flaps being turned up at the joints, preventing damage to the bottom of the cardboard box.

In a preferred embodiment, the load is lowered onto the top surface of the pallet that is replacing the pallet, but the invention is not limited to this and includes lowering the load onto surfaces other than a pallet.

The pallet extraction device of the present invention is for extracting only the pallet from a loaded pallet and lowering the load onto a predetermined surface, and is equipped with a movable table on which the loaded pallet is placed, a load receiving plate for receiving the load from the movable table, first and second load restriction plates arranged on either side of the load and having a height capable of restricting the passage of the load, a drive mechanism for the movable table which moves the movable table under the first load restriction plate and to the outside of the first load restriction plate, thereby causing the load on the pallet to abut against the first load restriction plate and be left behind, and a load receiving plate drive mechanism which moves the load receiving plate following the movable table from the outside to the inside of the second load restriction plate to receive the load left behind by the movable table, and then moves the load receiving plate under the second load restriction plate and to the outside of the second load restriction plate, thereby causing the load on the load receiving plate received from the movable table to abut against the second load restriction plate and be left behind. The moving table has a base, a loading platform supported on the base in a tiltable manner and on which a pallet with a load on its upper surface can be placed, and a tilting mechanism that tilts the loading platform so that the side of the second load restriction plate is lower.

In the pallet extractor of the present invention, when a pallet carrying a load is placed on the platform of the movable table, the drive mechanism of the movable table moves the movable table under the first load restriction plate and to the outside of the first load restriction plate, whereby the pallet is extracted and the load on the pallet hits the first load restriction plate and is left behind.
When the movable table moves, the tilting mechanism of the movable table tilts the loading platform so that the side with the second load restriction plate is lower. This tilting of the loading platform causes the load that has left the top surface of the pallet to slide down along the first and second load restriction plates. At the position where it has slid down, the top surface of the pallet and the bottom surface of the load are not in surface contact, but only one side edge is in contact. When the movable table is moved in this state, the top surface of the pallet does not rub against the bottom surface of the load, and the bottom surface of the load is not damaged or soiled.
When the moving table moves, the drive mechanism for the load receiving plate moves the load receiving plate following the moving table, and the load on the moving table that has struck the first load regulating plate and been left behind is transferred onto the load receiving plate and received.
Next, the load receiving plate drive mechanism moves the load receiving plate under the second load restricting plate and outward from the second load restricting plate, whereby the load receiving plate is removed, and the load on the load receiving plate hits the second load restricting plate and is left behind, and is lowered onto a predetermined surface.

In a preferred embodiment, at least one of the first and second load control plates can move toward and away from the other.

According to this embodiment, when a loaded pallet is placed on the moving table, the first and second load restriction plates are in a spaced apart position. When a loaded pallet is placed on the moving table, at least one of the load restriction plates approaches the other load restriction plate, sandwiching the load.

In a preferred embodiment, the tilting mechanism includes a support mechanism that supports the platform of the moving table so that it can swing, and a displacement mechanism that tilts the platform by displacing one side end of the platform in the vertical direction using the part supported by the support mechanism as a fulcrum.

In this embodiment, when the displacement mechanism is driven to displace one side end of the platform, for example downward, the platform tilts and inclines with the part supported by the support mechanism as a fulcrum, and the pallet placed on the platform is inclined so that the one side end of the platform is in a low inclined state.

The displacement mechanism can take a variety of forms, but one embodiment is composed of eccentric cams that are placed at the front and rear of both ends of the platform, and a rotation mechanism that rotates each eccentric cam at one end of the platform and each eccentric cam at the other end separately.

The pallet exchange device of this invention is for removing only a pallet from a loaded pallet and exchanging it for another pallet, and comprises a first moving table on which the other pallet to be exchanged is placed, a second moving table on which the loaded pallet is placed, a load receiving plate for receiving the load from the second moving table, first and second load restriction plates that have a height capable of restricting the passage of the load and are disposed on both sides of the load, and the second moving table passes under the first load restriction plate and moves to the outside of the first load restriction plate, causing the load on the pallet to hit the first load restriction plate and be left behind. The second moving table includes a drive mechanism for moving the load receiving plate from the outside to the inside of the second load restriction plate to receive the load left behind by the second moving table, a drive mechanism for the load receiving plate that moves the load receiving plate along with the second moving table to move from the outside to the inside of the second load restriction plate and then passes under the second load restriction plate to move to the outside of the second load restriction plate, thereby causing the load on the load receiving plate received from the second moving table to abut against the second load restriction plate and be left behind, and a drive mechanism for the first moving table that moves the first moving table to a position directly below the load receiving plate on the inside of the first and second load restriction plates to receive the load left behind by the load receiving plate. The second moving table has a base portion, a loading platform portion that is tiltably supported on the base portion and on which a pallet with a load on its upper surface is placed, and a tilting mechanism that tilts the loading platform portion so that the side of the second load restriction plate is lower.

In the pallet exchange device of the present invention, when a pallet carrying a load is placed on the loading platform of the second movable table, the drive mechanism of the second movable table moves the second movable table past under the first load restriction plate and to the outside of the first load restriction plate, whereby the pallet is removed and the load on the pallet hits the first load restriction plate and is left behind.
When the second movable table moves, the tilting mechanism of the second movable table tilts the loading platform so that the side with the second load restriction plate is lower. This tilting of the loading platform causes the load that has left the top surface of the pallet to slide down along the load restriction plate. At the position where it has slid down, the top surface of the pallet and the bottom surface of the load are not in surface contact, but only one side edge is in contact. When the second movable table is moved in this state, the top surface of the pallet does not rub against the bottom surface of the load, and the bottom surface of the load is not damaged or soiled.
When the second moving table moves, the drive mechanism for the load receiving plate moves the load receiving plate following the second moving table, and the load on the second moving table that has struck the first load regulating plate and been left behind is transferred onto the load receiving plate and received.
Next, the load receiving plate drive mechanism moves the load receiving plate under the second load limiting plate to the outside of the second load limiting plate, whereby the load receiving plate is removed and the load on the load receiving plate hits the second load limiting plate and is left behind. The left-behind load is lowered onto another pallet on the first moving table that has been moved directly under the load receiving plate by the first moving table drive mechanism, whereby the pallet exchange is completed.

In a preferred embodiment of the present invention, the system further includes a pallet recovery mechanism that recovers a pallet from the second moving table, and a pallet supply mechanism that supplies another pallet to be replaced onto the first moving table.

In this embodiment, the removed pallet is transported by the second moving table to the pallet recovery mechanism and recovered from the second moving table. Meanwhile, the pallet to be replaced is supplied onto the first moving table by the pallet supply mechanism, and the load is unloaded onto the pallet.

With this invention, there is no risk of the underside of the load being damaged or soiled when removing the pallet.

FIG. 4 is an explanatory diagram showing a pallet extraction method according to the present invention. FIG. 11 is an explanatory diagram showing the operation of a main component of the second moving table; 1 is a front view of a pallet exchange device according to an embodiment of the present invention. FIG. FIG. 4 is a plan view of the pallet exchange device of FIG. 3 . FIG. 4 is a side view of the pallet exchange device of FIG. 3 as viewed from the pallet recovery unit side. FIG. 4 is a side view of the pallet exchange device of FIG. 3 as viewed from the pallet supply unit side. FIG. 4 is a front view showing the configuration of a second moving table. FIG. 4 is a plan view showing a configuration of a second moving table. 4 is a side view showing the configuration and operation of a displacement mechanism. FIG. FIG. 5A to 5C are cross-sectional views showing the configuration and operation of a pallet supply mechanism. 5A to 5C are cross-sectional views showing the configuration and operation of a pallet recovery mechanism. FIG. 11 is a front view showing the procedure of a pallet replacement operation. FIG. 14 is a front view showing the continuation of the procedure of the pallet exchange work of FIG. 13. FIG. 15 is a front view showing the continuation of the procedure of the pallet exchange work of FIG. 14 . FIG. 16 is a front view showing the continuation of the procedure of the pallet exchange work of FIG. 15 . FIG. 11 is an explanatory diagram showing an enlarged view of the details of the pallet removal operation. FIG. 1 is a front view showing a conventional pallet removal method. FIG. 2 is a perspective view showing the appearance of a cardboard box.

(1) Pallet exchange procedure by implementing the pallet extraction method Figure 1 shows the procedure for exchanging a pallet by implementing the pallet extraction method of this invention. In the figure, the load C loaded on the pallet A is a plurality of packed cardboard boxes 300 (9 in the illustrated example) arranged in three rows and three columns for each layer and stacked in multiple tiers (3 tiers in the illustrated example). In the illustrated example, the load C is a plurality of packed and stacked cardboard boxes 300, but the load C to which this invention is applied is not limited to this and may be, for example, a single item.

(A) to (F) in the figure show a schematic diagram of the procedure for removing only pallet A from pallet A on which load C is loaded, and unloading load C onto another pallet B. Each cardboard box 300 has a rectangular parallelepiped shape as shown in FIG. 19, and is sealed with goods or other items stored inside. Pallet A is a wooden pallet with a roughly square planar shape, and has spaces a1 and a2 that run through it from the front to the back, into which the two arms of a forklift can be inserted.

1A shows a state immediately after a pallet A loaded with a load C has been placed by a forklift (not shown) on the second moving table 20. Note that the introduction of the pallet A onto the second moving table 20 can also be performed by a conveyor, as in the embodiment described later.
The second movable table 20, and the first movable table 40 and load receiving plate 30 described below, move back and forth within a specified range on a specified machine base, are equipped with wheels (not shown) for movement, and are driven by individual drive mechanisms not shown.
In the following description, the direction indicated by the arrow X in FIG. 1A is referred to as the left-right direction (both sides), the direction indicated by the arrow Z is referred to as the up-down direction, and the direction perpendicular to each of the X and Y directions is referred to as the front-back direction, and the same applies to FIG. 2, FIG. 3, etc.

First and second load restriction plates 5, 6 are located on either side of load C. Each load restriction plate 5, 6 is formed using a flat plate material made of metal or synthetic resin, and the opposing vertical faces on the inner surface are the faces that support load C. In the following explanation, the space between the first and second load restriction plates 5, 6 is referred to as the "inside", and the space on the opposite side of each load restriction plate 5, 6 is referred to as the "outside".

The areas below the load restriction plates 5, 6 are paths through which the first and second movable tables 40, 20 and the load receiving plate 30 can pass, and the height of each load restriction plate 5, 6 is set so that when a pallet A loaded with load C is placed on it, the passage of the pallet A is permitted but the passage of the load C is restricted. Note that the illustrated first and second load restriction plates 5, 6 have widths and heights that correspond to the front-to-rear width and height of the load C, but the heights may be less than the height of the load C.

The second load restriction plate 6 located on the left side is arranged so that it can approach and move away from the first load restriction plate 5 located on the right side, and the first load restriction plate 5 is fixed in a fixed position. Note that the first and second load restriction plates 5, 6 may be configured so that they can approach and move away from each other.

When pallet A loaded with load C is placed on second movable table 20, second movable table 20 is moved slightly so that load C comes into contact with the inner surface of first load restriction plate 5, as shown in FIG. 1(B). Next, second load restriction plate 6 is moved toward load C so that load C comes into contact with the inner surface of second load restriction plate 6. As a result, load C is sandwiched between first and second load restriction plates 5, 6, but is lightly held so that load C can move downward along the inner surfaces of first and second load restriction plates 5, 6.

The second movable table 20, the configuration and operation of which are described in detail in FIG. 2, has a structure in which a loading platform 20b is tiltably supported on a base 20a, and then, as shown in FIG. 1(C), the left end of the loading platform 20b is displaced downward to tilt the loading platform 20b slightly. This also tilts the pallet A on the second movable table 20, and the top surface of the pallet A is in a downward-leaning state to the left, with the second load restriction plate 6 side lower.

As the top surface of pallet A tilts, a gap S is created between the underside of load C and the top surface of pallet A. This gap S is larger on the side of the second load restriction plate 6. As shown by the dotted arrows in the figure, loads C1 to C3 in each row slide downward an amount according to the size of the gap S, using the first and second load restriction plates 5, 6 as guides. Because the top surface of pallet A is tilted, each load C in the bottom row that has slid down only comes into contact with the top surface of pallet A at the right end, and there is no surface contact between the underside of load C and the top surface of pallet A.

A horizontal load receiving plate 30 is waiting outside the second load restriction plate 6 so that it can move to the right in the figure. Next, as shown in FIG. 1(D), the second moving table 20 moves toward the first load restriction plate 5, and the load receiving plate 30 follows the second moving table 20 while approaching the second moving table 20. The height h of the upper surface of the load receiving plate 30 matches the height of the upper surface of the inclined lower end (left end) of pallet A.

As the second moving table 20 moves, the second moving table 20 and the pallet A on the second moving table 20 pass under the first load restriction plate 5 and move to the outside of the first load restriction plate 5, but the load C on the pallet A hits the first load restriction plate 5 and is left behind. As a result, as shown in FIG. 1(E), only the pallet A is removed, and the left-behind load C is transferred onto and received on the load receiving plate 30 following the second moving table 20.

When the second movable table 20 moves, the top surface of pallet A and the bottom surfaces of the loads C1 to C3 at the bottom of each row only come into contact at the right end as shown in FIG. 1(D), and therefore the bottom surface of load C is not rubbed by the top surface of pallet A. Also, because the height h of the top surface of the load receiving plate 30 is the same as the height of the top surface of the inclined lower end of pallet A, the top surface of the load receiving plate 30 is separated from the bottom surfaces of the loads C1 to C3 at the bottom of each row and does not rub against load C. Load C on pallet A gradually slides down as the second movable table 20 moves, and is lowered onto the load receiving plate 30.

Next, as shown in FIG. 1(F), the load receiving plate 30 supporting load C passes under the second load restriction plate 6 and moves to the outside of the second load restriction plate 6. This causes the load receiving plate 30 to be removed, while load C on the load receiving plate 30 hits the second load restriction plate 6 and is left behind. Directly below the load receiving plate 30, the first movable table 40 with the pallet B to be replaced placed on it is waiting, and the left-behind load C is lowered onto pallet B. This completes the removal of pallet A and the replacement with pallet B.

(2) Schematic Configuration and Tilting Operation of the Second Moving Table 20 FIGS. 2A to 2C show a schematic configuration of the second moving table 20 and the tilting operation in FIG. 1C.
The second movable table 20 has a two-tiered structure, with a lower base 20a and a loading platform 20b supported on the base 20a so as to be tiltable. A roller conveyor 21 is provided on the upper surface of the loading platform 20b, and a pallet A carrying a load is supported on the roller conveyor 21.

The second movable table 20 is provided with a tilting mechanism 27 that tilts the loading platform 20b. The tilting mechanism 27 includes a support mechanism 28 that supports the center of the loading platform 20b so that it can be raised and lowered and swung, and a displacement mechanism 29 that displaces the left and right side ends of the loading platform 20b in the up and down direction using the parts supported by the support mechanism 28 as fulcrums to tilt the loading platform 20b.

The illustrated displacement mechanism 29 includes a total of four eccentric cams 290, 291 arranged at the front and rear positions on both side ends of the loading platform 20b, and a rotation mechanism (not shown) that individually rotates the front and rear eccentric cams 290 at one end and the front and rear eccentric cams 291 at the other end. Note that the displacement mechanism 29 is not limited to using the eccentric cams 290, 291, and can also be configured using, for example, a cylinder mechanism.

The support mechanism 28 includes a free roller 280 supported via bearings on a support shaft 283 provided at each of the front and rear positions of the center of the loading platform 20b, and a pair of guide rails 281, 281 attached to each of the front and rear positions of the base 20b, which sandwich each free roller 280 from both sides and engage with the outer circumferential surface of the free roller 280. The outer circumferential surface of each free roller 280 engages with each of the guide rails 281, 281, so that the loading platform 20b can slide and tilt freely in the vertical direction along each of the guide rails 281, 281 while being prevented from swinging in the front and rear direction.

Each eccentric cam 290, 291 is supported rotatably on a support roller 296 that is supported rotatably at each of the front and rear positions of the base portion 20a. When both eccentric cams 290, 291 are in the rotation angle position shown in FIG. 2(A), the loading platform portion 20b is in the lowest position (hereinafter referred to as the "bottom dead center position") relative to the base portion 20a, and when they are in the rotation angle position shown in FIG. 2(B), the loading platform portion 20b is in the highest position (hereinafter referred to as the "top dead center position") relative to the base portion 20a. When each eccentric cam 290, 291 is in a different rotation angle position shown in FIG. 2(C), the loading platform portion 20b is in a state in which one side end is inclined lower than the other side end, that is, in a state downward to the left in the figure.

(3) Overall Configuration of Pallet Exchanger 200 FIGS. 3 to 6 show the configuration of a pallet exchanger 200 according to one embodiment of the present invention.
The pallet exchange device 200 is for extracting only a pallet from a loaded pallet and exchanging it with another pallet, and includes a configuration of a pallet extraction device for extracting only a pallet from a loaded pallet.

Note that Figure 3 shows the appearance of the pallet exchange device 200 when viewed from the front, Figure 4 shows the appearance when viewed from above, Figure 5 shows the appearance when viewed from the side of the pallet recovery section P2 described later, and Figure 6 shows the appearance when viewed from the side of the pallet supply section P3 described later.
3 to 6 show a state in which the first and second movable tables 40, 20 and the load receiving plate 30 described below are positioned at different positions. This state does not show a state in which a loaded pallet is waiting to be introduced. Note that Fig. 3 omits the illustration of the side wall 17 to which the discharge conveyor 110 and the holding claws 71, 81 described below are attached.

The pallet exchange device 200 is installed, for example, in a factory, a warehouse, a distribution center, etc. If a pallet is removed from a loaded pallet and belongs to another company, it is collected and returned to the owner.
The pallet exchange device 200 can be used not only for exchanging another company's pallet with a company's own pallet, but also for exchanging different types of pallets, exchanging old and new pallets, and for any other pallet exchange work.
The term "pallet" here broadly refers to a plate-like object used for transporting or storing loads, regardless of shape or material. In this embodiment, a commonly used pallet is used, that is, a pallet with a space extending from front to back between upper and lower opposing plates into which the forks of a forklift can be inserted.

The illustrated pallet exchange device 200 is a machine base 1 made up of multiple frames, etc., to which a pallet exchange mechanism, pallet collection mechanism 7, pallet supply mechanism 8, etc. are incorporated. The pallet exchange mechanism includes a second table movement mechanism 2, a load receiving mechanism 3, a first table movement mechanism 4, and first and second load restriction plates 5, 6, etc.

The center of the machine 1 is the work area P1 where the pallet replacement work is carried out. As shown in FIG. 4, the work area P1 is equipped with an input conveyor 100 for bringing in another company's loaded pallet (hereinafter referred to as the "second pallet") A, and an output conveyor 110 for carrying out the company's loaded pallet (hereinafter referred to as the "first pallet") B after the pallet replacement work is completed.

The loading conveyor 100 has multiple rollers 102 rotatably supported between side frames 101, 101 at predetermined intervals along the conveying direction of the loaded second pallet A (from top to bottom in Figure 4).
In addition, the output conveyor 110 has a number of rollers 112 rotatably supported between side frames 111, 111 at predetermined intervals along the conveying direction of the loaded first pallet B (the direction from top to bottom in Figure 4).

On one side of the work section P1 (left side in Figure 3) is the pallet supply section P3, where the company's first pallet B to be replaced is supplied, and on the other side (right side in Figure 3) is the pallet recovery section P2, where the removed second pallet A of another company is recovered.

(4) Configuration of the second table moving mechanism 2 The second table moving mechanism 2 has a second moving table 20 on which the second pallet A loaded with a load is placed. This second moving table 20 is located at the working section P1 when in a standby state, and moves back and forth between the working section P1 and the pallet collecting section P2 along the guide rails 11, 11 at the front and rear positions during the pallet exchange operation. The second moving table 20 is formed into a rectangular frame material to have an upper and lower two-stage structure described later. On the upper surface of the second moving table 20, a roller conveyor 21 is formed by a plurality of rollers 22 rotatably supported between the frame materials at a predetermined interval in the conveying direction of the second pallet A. The roller conveyor 21 is driven by a driving device using a motor 21A (shown in Figs. 7 and 8 described later) as a driving source. The driving device is mounted on the second moving table 20, and is linked to the carry-in conveyor 100 when carrying in a load.

As shown in FIG. 4, at the front and rear ends of the roller conveyor 21, a space S20 is formed into which a pair of arms 721, 721 of a pallet support 72 of the pallet recovery mechanism 7, which will be described later, can enter by increasing the spacing between the rollers 22. The roller conveyor 21 is linked to the carry-in conveyor 100, so that the second pallet A carrying the load transported on the carry-in conveyor 100 is carried onto the second moving table 20 by the roller conveyor 21.

Rollers 23 that roll on the guide rails 11 are provided at the four corners of the lower part of the second moving table 20. The roller 23 at one end of the four rollers 23 is driven by a drive mechanism 25 (described later) mounted on the second moving table 20, so that the second moving table 20 moves on the guide rails 11 by itself.
In addition, the drive mechanism 25 is not limited to being mounted on the second moving table 20 and causing the second moving table 20 to move on its own, but may be configured in such a way that a motor is installed on the machine base 1 and the second moving table 20 is pulled and moved via a sprocket, chain, etc.

(5) Specific configuration of the second moving table 20 Figures 7 and 8 show a specific configuration of the second moving table 20. The second moving table 20 in the illustrated example is composed of a base portion 20a having a rectangular planar shape, and a loading platform portion 20b having a rectangular planar shape, which is supported on the base portion 20a so as to be able to rise and fall and to tilt, and on which a roller conveyor 21 is provided on the upper surface. A second pallet A carrying a load C is introduced onto the roller conveyor 21 and supported thereon.

A drive mechanism 25 is mounted on the base portion 20a of the second moving table 20, and the rollers 23 are rotated by the drive mechanism 25, causing the second moving table 20 to move on the guide rails 11. The drive mechanism 25 includes a motor 24 as a drive source, and a power transmission mechanism 26 that transmits the drive of the motor 24 to one of the rollers 23. When the second moving table 20 is moved from the working section P1 to the pallet collection section P2 by the drive mechanism 25, the loaded second pallet A is extracted.

The loading platform 20b is provided with a tilting mechanism 27 that tilts the loading platform 20b so that the side of the second load restriction plate 6 is lower than the side of the first load restriction plate 5. The tilting mechanism 27 includes a support mechanism 28 that supports the center of the loading platform 20b so that it can be raised and lowered and tilted, and a displacement mechanism 29 that displaces the end of the loading platform 20b on the side of the second load restriction plate 6 downward relative to the end on the side of the first load restriction plate 5, using the part supported by the support mechanism 28 as a fulcrum, to tilt the loading platform 20b downward to the left in the figure.

The illustrated displacement mechanism 29 is composed of eccentric cams 290, 291 that are respectively arranged at the front and rear positions on both side ends of the loading platform portion 20b, and first and second rotation mechanisms 292, 293 that individually rotate the two front and rear eccentric cams 290 on the first load restriction plate 4 side and the front and rear eccentric cams 291 on the second load restriction plate 6 side.

Each eccentric cam 290 at one of the front and rear positions is provided on a rotating shaft 294 whose both ends are supported by the front and rear frames 201, 202. The first rotating mechanism 292 rotates the rotating shaft 294, for example, in a counterclockwise direction. Each eccentric cam 291 at the other of the front and rear positions is provided on a rotating shaft 295 whose both ends are supported between the front and rear frames 201, 202. The second rotating mechanism 293 rotates the rotating shaft 295, for example, in a clockwise direction. Note that the displacement mechanism 29 is not limited to one configured using the eccentric cams 290, 291, and may be configured to displace one or both ends of the loading platform portion 20b in the vertical direction by a cylinder mechanism, for example.

The first and second rotation mechanisms 292, 293 each include a motor 296, 297 as a drive source, and a gear reduction mechanism 298, 299 that reduces the rotation speed of each motor 296, 297 to an optimal value and transmits the rotation speed to the rotation shaft 294, 295.

The support mechanism 28 includes free rollers 280 that are supported rotatably via bearings on support shafts 283 provided in the longitudinal center of the front and rear frames 201, 202 of the loading platform 20b, and a pair of guide rails 281, 282 that are attached to the longitudinal center of the front and rear frames 203, 204 of the base 20a, and that sandwich each free roller 280 from both sides and engage freely with the outer circumferential surface of the free roller 280.

Each roller 280 has a groove 280a around its outer periphery, while the opposing surfaces of each guide rail 281, 282 have ridges 281a, 282a formed thereon that slidably engage with the groove 280a of the roller 280. Each ridge 281a, 282a has a triangular cross-sectional shape perpendicular to the length direction. Each free roller 280 is supported so that it can slide freely up and down along each guide rail 281 while its deflection in the front-to-back direction is restricted by the ridges 281a, 282a of the guide rails 281 engaging with the groove 280a.

Each eccentric cam 290, 291 is supported rotatably on a support roller 296. Figure 9 is an enlarged side view of the part indicated by the dashed line in Figure 8, in which one end of the support shaft 297 is fixed to either the front or rear frame 203, 204 of the base portion 20b, and the support roller 296 is supported rotatably on the support shaft 297.

The height of the loading platform 20a changes according to the rotation angle position of each eccentric cam 290, 291, and is displaced between the lowest bottom dead center position (FIGS. 2(A) and 9(A)) and the highest top dead center position (FIGS. 2(B) and 9(B)) relative to the base 20b. In addition, the loading platform 20a is set in a state in which one end is tilted lower than the other end (FIG. 2(C)) by changing the rotation angle position of the eccentric cam 291 at one end by, for example, 180 degrees relative to the rotation angle position of the eccentric cam 290 at the other end.

(6) Configuration of the first load restriction plate 5 Returning to Fig. 3, the first load restriction plate 5 is fixed on the machine base 1, and when the second moving table 20 is moved from the working section P1 to the pallet recovery section P2 in removing the second pallet A, only the load on the second pallet A hits the plate and is left behind at the working section P1. This first load restriction plate 5 is installed between the working section P1 and the pallet recovery section P2 at a position corresponding to the height of the load. The load on the second pallet A hits the first load restriction plate 5, but the second pallet A passes under the first load restriction plate 5 together with the second moving table 20 and moves from the working section P1 to the pallet recovery section P2.

(7) Configuration of the load receiving mechanism 3 The load receiving mechanism 3 has a load receiving plate 30 for receiving and supporting loads left behind in the working section P1 from below. This load receiving plate 30 is located in the pallet supply section P3 in a standby state, and reciprocates between the pallet supply section P3 and the working section P1 during a pallet exchange operation. That is, the load receiving plate 30 receives loads from the second moving table 20 on the outward journey, and delivers the loads to the first moving table 40 on the return journey.

The load receiving plate 30 in the illustrated example has opposing walls 31, 31 formed by bending both ends of a thin plate material downward. The spacing between the opposing walls 31 is set so that when the first moving table 40 described below is moved below the load receiving plate 30, the first pallet B supported on the first moving table 40 fits between the opposing walls 31, 31.

Rollers 32 that roll on guide rails 12, 12 at the front and rear positions of the opposing walls 31, 31 are provided, respectively. Note that the guide rails 12, 12 are located above the guide rails 11, 11 that move the first and second moving tables 40, 20.

As shown in Figures 3 and 5, the load receiving plate 30 is connected to a drive mechanism 33 and reciprocates on the guide rail 12. The drive mechanism 33 includes a motor 34 as a drive source, left and right drive sprockets 35 driven by the motor 34, and two chains 37 respectively stretched between each drive sprocket 35 and left and right driven sprockets 36. Each chain 37 is stretched along the guide rails 12, 12, and both ends of each chain 37 are connected to both side end faces of the load receiving plate 30.

When the load receiving plate 30 is moved from the pallet supply section P3 to the work section P1 by the drive mechanism 33, the motor 34 of the load receiving mechanism 3 and the motor 26 of the second table moving mechanism 2 are operated synchronously, and the load receiving plate 30 follows in a state close to the second moving table 20. The second pallet A is removed by the movement of the second moving table 20, and the load on the second pallet A is transferred from the second pallet A onto the load receiving plate 30 and supported.

When the load receiving plate 30 is returned from the working section P1 to the pallet supply section P3, the motor 34 of the load receiving mechanism 3 is rotated in the reverse direction, and this movement of the load receiving plate 30 causes the load receiving plate 30 to be removed from the load.

(8) Configuration of the second load control plate 6 The second load control plate 6 is intended to prevent loads on the load receiving plate 30 from hitting it and being left behind in the working section P1 when the load receiving plate 30 is returned from the working section P1 to the pallet supply section P3, and is installed between the working section P1 and the pallet supply section P3 in accordance with the height position of the load on the machine base 1 so that only the load receiving plate 30 passes under the second load control plate 6.

Figure 10 shows one embodiment of the second load restriction plate 6, both ends of which are connected to drive mechanisms 60, 60 so that it can move toward and away from the first load restriction plate 5. Each drive mechanism 60 has a rodless cylinder 61 as a drive source and a pair of intersecting links 62, 63.

The lower end of one link 62 is rotatably supported by a fixed frame 19 vertically installed on the machine base 1, and the lower end of the other link 62 is rotatably supported by the second load restriction plate 6. The upper end of one link 62 is supported by a guide 64 provided on the second load restriction plate 6 so that it can slide freely up and down. The upper end of the other link 63 is connected to a rodless cylinder 61 provided on the fixed frame 19. By synchronously driving the rodless cylinders 61 of both drive mechanisms 60, the links 62 and 63 expand and contract, and as a result, the second load restriction plate 6 advances and retreats relative to the first load restriction plate 5. The drive mechanism 60 is not limited to the form described above in this embodiment.

(9) Configuration of First Table Moving Mechanism 4 The first table moving mechanism 4 has a first moving table 40 on which the first pallet B supplied by the pallet supply mechanism 8 is placed. This first moving table 40 is located at the pallet supply section P3 in a standby state, and moves back and forth along the guide rails 11, 11 between the pallet supply section P3 and the working section P1 during a pallet changing operation.

The first moving table 40 is formed by framing a frame material in a rectangular shape, and a roller conveyor 41 that works in conjunction with the discharge conveyor 110 is provided on the upper surface of the first moving table 40. The roller conveyor 41 has multiple rollers 42, which are rotatably supported between the frame materials and arranged at predetermined intervals in the transport direction of the first pallet B, and is driven by a drive device (not shown) that uses a motor as a drive source. The drive device is mounted on the first moving table 40, and works in conjunction with the discharge conveyor 110 when unloading cargo.

As shown in FIG. 4, at the front and rear ends of the roller conveyor 41 in the conveying direction, a space S40 is formed into which a pair of arms 821, 821 of the pallet support 82 described later can enter by increasing the spacing between the rollers 42. This roller conveyor 41 is linked to the carry-out conveyor 110, and the first pallet B loaded on the first moving table 40 is carried out onto the carry-out conveyor 110 by the roller conveyor 41, and then the first pallet B is transported by the carry-out conveyor 110.

Rollers 43 that roll on each guide rail 11 are provided at the four corners of the lower part of the first moving table 40. The first moving table 40 is equipped with a drive mechanism (not shown), and the rollers 43 rotate when driven by the drive mechanism, causing the first moving table 40 to move by itself along the guide rails 11. The drive mechanism is configured similarly to the drive mechanism 25 of the second moving table 20, and includes a motor as a drive source and a power transmission mechanism that transmits the drive of the motor to one of the rollers 43.

With the first pallet B supported on the upper surface of the first moving table 40, the drive mechanism is driven to move the first moving table 40 from the pallet supply section P3 to below the load receiving plate 30 positioned in the work section P1, and then the load receiving plate 30 is returned from the work section P1 to the pallet supply section P3, whereby the load on the load receiving plate 30 is transferred onto and supported on the first pallet B on the first moving table 40.

(10) Configuration of the pallet recovery mechanism 7 The pallet recovery mechanism 7 is provided in the pallet recovery section P2, and recovers and holds the second pallet A carried from the working section P1 to the pallet recovery section P2 by the second moving table 20. The illustrated example of the pallet recovery mechanism 7 includes a pallet holding mechanism 70, guide rails 16, a pallet support body 72, and a lifting mechanism 73, as shown in Figures 3 and 5.

The pallet holding mechanism 70 is configured to hold second pallets A stacked vertically in multiple tiers in the pallet holding space S2 set above the second moving table 20 of the pallet recovery section P2, and is also capable of holding an additional second pallet A on the bottom tier of the held second pallet A.

The pallet support 72 is capable of supporting the second pallet A from below, and in the standby state is located between the pallet holding space S2 and the standby position of the second moving table 20. The lifting mechanism 73 raises and lowers the pallet support 72 along two guide rails 16 provided on the fixed frame 161 described later.

The pallet holding mechanism 70 has multiple holding claws 71 (four in this embodiment) for holding the second pallet A in the pallet holding space S2 in a vertically stacked state across multiple levels, and a spring (not shown) that biases each holding claw 71 in a closing direction.

The holding claws 71 are attached to the side walls 17 provided on the machine base 1 along the movement direction of the second moving table 20 in order to support the four corner positions of the second pallet A. Each holding claw 71 closes by spring force after being pushed open by the second pallet A pushed up by the pallet support 72, whereby each holding claw 71 engages with the second pallet A to hold it.

The guide rails 16 are located at least between the pallet holding space S2 and the standby position of the second moving table 20, and are provided on two left and right sides along the vertical direction on a fixed frame 161 provided at the end of the machine base 1 in the longitudinal direction.

The pallet support 72 includes a connecting base end 722 that extends along the width direction of the second moving table 20 and has a length approximately equal to the width of the second moving table 20, and a pair of arms 721, 721 that are connected together via the connecting base end 722 and extend from both ends of the connecting base end 722 along the movement direction of the second table 20. The pair of arms 721, 721 have a length capable of supporting the second pallet A, and are spaced apart at a distance capable of supporting the second pallet A.

A slide member 723 is attached to the rear surface of the connecting base end 722 of the pallet support 72 that faces the guide rail 16. A groove with a T-shaped cross section is formed in the slide member 723. The groove of this slide member 723 is inserted into the rail portion of the guide rail 16 that has a shape corresponding to the groove, allowing the pallet support 72 to slide up and down along the guide rail 16.

The lifting mechanism 73 includes a chain 74 and a drive device 76 capable of moving the chain 74 in both the up and down directions. One end of the chain 74 is attached to the connecting base end 722 of the pallet support 72, and the other end has a balance weight 75 attached. The balance weight 75 is supported so as to slide freely on a guide rail 15 provided along the up and down direction of the fixed frame 161.

The lifting mechanism 73 raises and lowers the pallet support 72 while maintaining the pallet support 72 in a horizontal position. When in a standby state, the pallet support 72 lowers below the upper surface of the second moving table 20 and enters the space S20 between the rollers 22 of the conveyor 21 provided on the upper surface of the second moving table 20, as shown in FIG. 3.

(11) Configuration of pallet supply mechanism 8 The pallet supply mechanism 8 is provided in the pallet supply section P3, and supplies a first pallet B to the upper surface of the first moving table 40. The illustrated pallet supply mechanism 8 includes a pallet holding mechanism 80, guide rails 13, a pallet support body 82, and a lifting mechanism 83, as shown in Figures 3 and 6.

The pallet holding mechanism 80 holds the first pallets B in a vertically stacked state across multiple levels in the pallet holding space S3 set above the standby position of the first moving table 40, and is configured to be able to separate the bottommost first pallet B from the first pallet B above it to release the held state.

The pallet support 82 is capable of supporting the first pallet B from below, and in the standby state is located between the pallet holding space S3 and the standby position of the first moving table 40. The lifting mechanism 83 raises and lowers the pallet support 82 along two guide rails 13 provided on the fixed frame 131 described later.

The pallet holding mechanism 80 comprises a number of holding claws 81 (four in this embodiment) for holding the first pallet B in the pallet holding space S3 in a vertically stacked state across multiple levels, and a drive mechanism (not shown) for opening and closing each holding claw 81.

The holding claws 81 are attached to the side walls 18 provided on the machine base 1 along the movement direction of the first moving table 40 in order to support the four corner positions of the first pallet B. Each holding claw 81 is pushed open by the pallet support 82 being pushed up, whereby each holding claw 81 is disengaged from the bottom first pallet B and each holding claw 81 engages with the first pallet B above it to hold the first pallet B.

The guide rails 13 are located at least between the pallet holding space S3 and the standby position of the first moving table 40, and are provided on the left and right along the vertical direction on a fixed frame 131 provided at the end of the machine base 1 in the longitudinal direction.

The pallet support 82 includes a connecting base end 822 that extends along the width direction of the first moving table 40 and has a length approximately equal to the width of the first moving table 40, and a pair of arms 821, 821 that are connected together via the connecting base end 822 and extend from both ends of the connecting base end 822 along the movement direction of the first table 40. The pair of arms 821, 821 have a length capable of supporting the first pallet B, and are spaced apart at a distance capable of supporting the first pallet B.

A slide member 823 is attached to the rear surface of the connecting base end 822 of the pallet support 82 that faces the guide rail 13. A groove with a T-shaped cross section is formed in the slide member 823. The groove of this slide member 823 is inserted into the rail portion of the guide rail 13 that has a shape corresponding to the groove, allowing the pallet support 82 to slide up and down along the guide rail 13.

The lifting mechanism 83 includes a chain 84 and a drive device 86 capable of moving the chain 84 in both the up and down directions. One end of the chain 84 is attached to the base end 822 of the pallet support 82, and a balance weight 85 is attached to the other end. The balance weight 85 is supported so as to slide freely on a guide rail 13 provided on the fixed frame 131 along the up and down direction.

This lifting mechanism 83 lifts and lowers the pallet support 82 while maintaining a horizontal position. When lowering, the pallet support 82 descends below the top surface of the first moving table 40 as shown in FIG. 3, and enters the space S40 between the rollers 42 of the roller conveyor 41 provided on the top surface of the first moving table 40.

(12) Operation of Pallet Supply Mechanism 8 FIGS. 11A to 11F show the configuration and operation of the pallet supply mechanism 8 of the pallet supply section P3.
To supply a first pallet B to be replaced onto the first moving table 40, first, the pallet support 82 is raised to the height of the pallet holding mechanism 80 to support the stack of first pallets B (FIG. 11(A)). At this time, the holding claws 81 hold the top plate of the lowermost first pallet B1. Next, the pallet support 82 is slightly raised to set the holding claws 81 in a rotatable state (FIG. 11(B)).

Next, the drive mechanism opens the holding claws 81 (FIG. 11(C)), and then the pallet support 82 is lowered by the thickness of the first pallet B1 (FIG. 11(D)). When the holding claws 81 are closed in this state, the holding claws 81 are able to hold the first pallet B2, which is the second tier from the bottom (FIG. 11(E)).

Next, the pallet support 82 is lowered so that only the bottom first pallet B1 is supported on the pallet support 82, and the next first pallet B2 and the stack on it are held by the holding claws 81 (Figure 11 (F)). The first pallet B1 is placed on the first moving table 40 by lowering the pallet support 82 to a position where it enters the space S40 between the rollers 42 of the first moving table 40.

(13) Operation of Pallet Collection Mechanism 7 FIGS. 12A to 12F show the configuration and operation of the pallet collection mechanism 7 of the pallet collection section P2.
The pallet support 72 is in the lowest position when waiting to collect the second pallet A. As the second moving table 20 moves from the working section P1 to the pallet collecting section P2, the pallet support 72 enters the space S20 between the rollers 22 of the roller conveyor 21 provided on the upper surface of the second moving table 20.

The second pallet A1 is placed on the second moving table 20 which is moving to the pallet collection section P2. When the pallet support 72 is raised, the second pallet A1 is supported by the pallet support 72 and rises (Fig. 12 (A)), supporting the stack of second pallets A. At this time, the holding claws 71 hold the top plate of the second pallet A2, which is the bottom layer of the stack. Next, the pallet support 72 is raised slightly, setting the holding claws 71 in a rotatable state (Fig. 12 (B)).

Next, the holding claws 71 are opened (FIG. 12(C)), and then the pallet support 72 and the second pallet A1 are raised by the thickness of the second pallet A1 (FIG. 12(D)). When the holding claws 71 are closed in this state, the holding claws 71 are able to hold the second pallet A1 (FIG. 12(E)). Next, when the pallet support 72 is lowered, the second pallet A1 added to the bottom layer of the stack of second pallets A is held by the holding claws 71 (FIG. 12(F)).

In the operation example of FIG. 12, the second pallet A1 is added to the bottom layer of the stack of second pallets A, but if there is no stack of second pallets A in the pallet recovery section P2, the second pallet A1 that has been brought is held by the holding claws 71. In this case, after the holding claws 71 are opened, the pallet support 72 is raised and the holding claws 71 are closed, so that the holding claws 71 are able to hold the second pallet A1.

(14) Pallet exchange operation by pallet exchange device 200 Figures 13 to 16 show the pallet exchange operation by the pallet exchange device 200 configured as described above. By sequentially performing this operation, only the second pallet A carrying cargo C is removed from the second pallet A and replaced with the first pallet B.

First, the second moving table 20 of the second table moving mechanism 2 is placed on standby at the working section P1, and the load receiving plate 30 of the load receiving mechanism 3 and the first moving table 40 of the first table moving mechanism 4 are placed on standby at the pallet supply section P3 (FIG. 13(A)). At this time, a plurality of first pallets B are held in a stacked state by the pallet holding mechanism 80 of the pallet supply mechanism 8 in the pallet holding space S3 of the pallet supply section P3. Furthermore, the bottommost first pallet B1 is separated from the stack of first pallets B and supported by the pallet support 82, and is located immediately above the load receiving plate 30. In this standby state, as shown in FIG. 13(B), the carry-in conveyor 100 carries the second pallet A1 loaded with load C into the working section P1 and introduces it onto the second moving table 20.

When pallet A loaded with load C is introduced onto second movable table 20, second movable table 20 is moved slightly toward load C so that load C hits first load restriction plate 5. Next, drive mechanism 60 moves second load restriction plate 6 toward load C so that load C hits second load restriction plate 6. As a result, load C is sandwiched between first and second load restriction plates 5, 6 (FIG. 13(C)), and load C is lightly clamped so that it can move downward along the inner surfaces of first and second load restriction plates 5, 6.

Next, the tilting mechanism 27 of the second moving table 20 is operated. First, the displacement mechanism 29 displaces the loading platform 20b upward relative to the base 20a while keeping it in a horizontal position, and then, as shown in FIG. 14(A), displaces one side end of the loading platform 20b downward so that the side of the second load restriction plate 6 is lower, slightly tilting the loading platform 20b. This also tilts the second pallet A on the loading stage 20b, and the top surface of the second pallet A is downwardly slanted to the left in the figure.

As the top surface of the second pallet A tilts, a gap S is created between the underside of load C and the top surface of the second pallet A. This gap S is larger on the side of the second load restriction plate 6, and as shown enlarged in Figure 17 (A), loads C1 to C3 in each row slide downward along the first and second load restriction plates 5, 6 by an amount corresponding to the size of the gap S. As the top surface of the second pallet A is tilted, the bottommost load C that has slid down only comes into contact with the top surface of the second pallet A at the right edge R, and there is no surface contact between the underside of load C and the top surface of the second pallet A.

Next, the drive mechanism 25 of the second table moving mechanism 2 is driven to move the second moving table 20 from the working section P1 toward the pallet collection section P2 while keeping the loading platform section 20b tilted as shown in FIG. 14(B), and the drive mechanism 33 of the load receiving mechanism 3 is driven to move the load receiving plate 30 close to the second moving table 20 and follow it, moving it from the pallet supply section P3 toward the working section P1.

During this movement, the load C on the second moving table 20 hits the inner surface of the first load control plate 5 and is left behind, but the second pallet A moves together with the second moving table 20 to the pallet recovery section P2 (Figure 14 (C)). The load receiving plate 30 follows the movement of the second moving table 20, so the load C that is left behind is transferred from the second pallet A onto the load receiving plate 30 and supported.

When the second movable table 20 moves, as shown in an enlarged view in FIG. 17(B), the upper surface of the second pallet A and the lower surface of the lowest load C only come into contact at the right end R, and do not make surface contact, so the upper surface of the second pallet A does not rub against the lower surface of the load C. Also, because the height h of the upper surface of the load receiving plate 30 is the same as the height of the upper surface of the inclined lower end of the second pallet A, the upper surface of the load receiving plate 30 is separated from the lower surface of the lowest load C and does not rub against the load C. As the second movable table 20 moves, the load C on the second movable table 20 gradually slides down from the second movable table 20 to the load receiving plate 30 and is supported on the load receiving plate 30.

When the second moving table 20 reaches the pallet collection section P2 and the load receiving plate 30 reaches the work section P1, a position sensor (not shown) detects this, the drive mechanisms 25, 33 stop driving, and the second moving table 20 and the load receiving plate 30 stop moving. Also, in the pallet supply section P3, the pallet support 82 descends and enters the space S40 between the rollers 42 of the roller conveyor 41 of the first moving table 40, so that the first pallet B1 is placed on the top surface of the first moving table 40.

Next, the drive mechanism 45 of the first table moving mechanism 4 is driven to move the first moving table 40 from the pallet supply section P3 toward the working section P1, and the first moving table 40 enters and is positioned below the load receiving plate 30 positioned in the working section P1 (FIG. 15(A)). At this time, the drive mechanism 60 is driven to move the second load restriction plate 6 backward and to position it in its original position.

Next, the drive mechanism 33 of the load receiving mechanism 3 is driven, and as shown in FIG. 15(B), the load receiving plate 30 returns from the working section P1 toward the pallet supply section P3. During this return operation, the load C on the load receiving plate 30 hits the second load restriction plate 6 and is left behind in the working section P1, but because the first moving table 40 on which the first pallet B1 is placed is located below the load receiving plate 30, the left-behind load C is transferred from the load receiving plate 30 onto the first pallet B1 and supported.

In FIG. 15(A), when the first moving table 40 moves from the pallet supply section P3 toward the working section P1, the pallet support 82 of the pallet supply mechanism 8 in the pallet supply section P3 goes through the operations shown in FIG. 11(A) to (F) above, supporting the first pallet B at the bottom level, and descends to a standby state (FIG. 15(B)).

In addition, in FIG. 14(C), when the second moving table 20 reaches the pallet collection section P2, the pallet support 72 of the pallet collection mechanism 7 rises while supporting the second pallet A at the pallet collection section P2 through the operations shown in FIG. 12(A)-(F), and adds it to the bottom layer of the stack of second pallets A (FIG. 15(A)). After that, the pallet support 72 enters the space S20 between the rollers 22 of the roller conveyor 21 provided on the upper surface of the second moving table 20 and enters a standby state (FIG. 15(B)).

As shown in FIG. 15C, when the load receiving plate 30 reaches the pallet supply section P3, a position sensor (not shown) detects this, the drive mechanism 33 stops driving, and the load receiving plate 30 stops its returning operation.
This completes the operation of removing only the second pallet A loaded with the load C from the second pallet A and replacing it with the first pallet B1.

After the load receiving plate 30 returns to the pallet supply section P3, the first pallet B1 loaded with load C is removed by the discharge conveyor 110 (FIG. 16(A)). After that, the drive mechanism 45 of the second table moving mechanism 4 is driven to move the second moving table 20 from the pallet collection section P2 to the working section P1, and the drive mechanism 25 of the first table moving mechanism 2 is driven to move the first moving table 40 from the working section P1 to the pallet supply section P3. When the second moving table 20 and the first moving table 40 reach the working section P1 and the pallet supply section P3, respectively, a position sensor (not shown) detects this, and the drive mechanisms 25 and 45 stop driving, and the first and second moving tables 40 and 20 stop moving (FIG. 16(B)). In this state, the next pallet exchange operation is awaited.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

1 Machine base 2 Second table moving mechanism 3 Load receiving mechanism 4 First table moving mechanism 5 First load limiting plate 6 Second load limiting plate 7 Pallet recovery mechanism 8 Pallet supply mechanism 20 Second moving table 20a Base portion 20b Loading platform portion 25 Second table drive mechanism 27 Tilting mechanism 28 Support mechanism 29 Displacement mechanism 30 Load receiving plate 33 Load receiving plate drive mechanism 40 First moving table 45 First moving table drive mechanism 200 Pallet exchange device 300 Cardboard box A Second pallet B First pallet C Load

Claims (9)

A pallet removal method for removing only a pallet from a loaded pallet and lowering the load onto a predetermined surface, comprising the steps of:
placing the pallet on which the load is loaded onto a moving table and positioning first and second load restriction plates on both sides of the load for restricting the passage of the load;
tilting the movable table so that the second load limiting plate side of the upper surface of the pallet is lower;
a step of removing the pallet by passing the movable table under a first load restriction plate in a tilted state, and receiving the load that hits the first load restriction plate and is left behind by a load receiving plate following the movable table;
and removing the load receiving plate by passing it under a second load restricting plate, and lowering any load that has struck the second load restricting plate and been left behind onto a predetermined surface. The pallet extraction method according to claim 1, wherein the load is a stack of packed cardboard boxes aligned in multiple rows and columns for each tier, and each cardboard box has a bottom formed by folding flaps from all four sides. The pallet extraction method according to claim 1, in which the load is lowered onto the top surface of another pallet that is to be replaced with the pallet. A pallet extracting device for extracting only a pallet from a loaded pallet and lowering the load onto a predetermined surface, comprising:
a moving table on which the loaded pallet is placed;
a load receiving plate for receiving loads from the moving table;
First and second load restriction plates having a height capable of restricting the passage of the load and disposed on both sides of the load;
a driving mechanism for the moving table that passes under the first load restriction plate and moves to the outside of the first load restriction plate, thereby causing the load on the pallet to abut against the first load restriction plate and be left behind;
a load receiving plate drive mechanism for moving the load receiving plate from the outside to the inside of the second load restriction plate following the moving table in order to receive the load left behind by the moving table, and then passing the load receiving plate under the second load restriction plate and moving it to the outside of the second load restriction plate, thereby causing the load on the load receiving plate received from the moving table to abut against the second load restriction plate and be left behind;
The movable table is a pallet removal device having a base portion, a loading platform portion supported on the base portion in a tiltable manner and on which a pallet with a load on its upper surface is placed, and a tilting mechanism that tilts the loading platform portion so that the side of the second load control plate is lower. The pallet extractor according to claim 4, wherein at least one of the first and second load control plates can move toward and away from the other. The pallet extractor according to claim 4, wherein the tilting mechanism includes a support mechanism that supports the platform of the moving table so that it can swing, and a displacement mechanism that displaces one side end of the platform in the vertical direction with a part supported by the support mechanism as a fulcrum to tilt the platform. The pallet extractor according to claim 6, wherein the displacement mechanism is composed of eccentric cams arranged at the front and rear positions of both ends of the loading platform, and a rotating mechanism that rotates each eccentric cam at one end of the loading platform and each eccentric cam at the other end of the loading platform separately. A pallet exchange device for extracting only a pallet from a loaded pallet and exchanging it with another pallet,
a first moving table on which another pallet to be replaced is placed;
a second movable table on which the loaded pallet is placed;
a load receiving plate for receiving loads from the second moving table;
First and second load restriction plates having a height capable of restricting the passage of the load and disposed on both sides of the load;
a drive mechanism for a second moving table that passes under the first load restriction plate and moves to the outside of the first load restriction plate, thereby causing the load on the pallet to abut against the first load restriction plate and be left behind;
a load receiving plate drive mechanism for moving the load receiving plate from the outside to the inside of the second load restriction plate following the second moving table to receive the load left behind by the second moving table, and then passing the load receiving plate under the second load restriction plate and moving it to the outside of the second load restriction plate, thereby causing the load on the load receiving plate received from the second moving table to abut against the second load restriction plate and be left behind;
a drive mechanism for a first moving table for moving the first moving table to a position immediately below the load receiving plate on the inner side of the first and second load regulating plates in order to receive the load left behind by the load receiving plate;
The second movable table is a pallet removal device that has a base portion, a loading platform portion that is tiltably supported on the base portion and on which a pallet with a load on its upper surface is placed, and a tilting mechanism that tilts the loading platform portion so that the side of the second load control plate is lower. The pallet exchange device according to claim 8, further comprising a pallet recovery mechanism that recovers a pallet from the second moving table, and a pallet supply mechanism that supplies another pallet to be exchanged onto the first moving table.

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