JP7511896B2 - Pallet-based load transport device - Google Patents

Description

This invention relates to a load conveying device used to transport loads between multiple floors in factories, warehouses, etc., and in particular to a load conveying device that uses pallets to transport loads on pallets.

As shown in Figure 12, this type of load transport device conventionally includes a lifting mechanism 1 having a lifting table 10 that moves up and down between multiple floors (between the first and second floors in Figure 12), and a load loading/unloading device 2 that is installed at entrances G1, G2 on each floor of the lifting mechanism 1 and is capable of loading and unloading a loaded pallet (hereinafter referred to as a "loaded pallet") P1 and an unloaded pallet (hereinafter referred to as an "empty pallet") P2 into and out of the lifting table 10 simultaneously in parallel.

In the following description, the direction facing the entrances G1 and G2 of the lifting mechanism 1, i.e., the direction indicated by the arrow x in FIG. 12, is referred to as the front-rear direction, the width direction of the entrances G1 and G2 of the lifting mechanism 1, i.e., the direction indicated by the arrow y in FIG. 12, is referred to as the left-right direction or both-side direction, and the direction perpendicular to the front-rear direction and left-right direction, i.e., the direction indicated by the arrow z in FIG. 12, is referred to as the up-down direction.

The lifting mechanism 1 has a lifting table 10 with two upper and lower conveyors 11, 12 for horizontally transporting the loaded pallet P1 and the empty pallet P2 in the forward and backward directions. The load carrying-in/out device 2 is composed of a pair of load carrying-in/out mechanisms 200L, 200R, each of which has a load carrying chain conveyor 3, 3 that cooperates with the upper conveyor conveyor (hereinafter referred to as the "first conveyor") 11 of the lifting table 10 to carry in and out the loaded pallet P1, and an empty pallet carrying chain conveyor 4, 4 that cooperates with the lower conveyor conveyor (hereinafter referred to as the "second conveyor") 12 of the lifting table 10 to carry in and out the empty pallet P2. The first and second conveyors 11, 12 of the lifting table 10 are, for example, roller conveyors.

The left and right chain conveyors 3, 3 for transporting loads and the left and right chain conveyors 4, 4 for transporting empty pallets face each other across a spatial area for work (hereinafter referred to as the "work area") S facing the entrances G1, G2 of the lifting mechanism 1, and move forward and backward from both the left and right sides of the work area S. Although not shown, each load loading/unloading mechanism 200L, 200R incorporates a first conveyor movement mechanism that moves the load transport chain conveyor 3 forward and backward, and a second conveyor movement mechanism that moves the empty pallet transport chain conveyor 4 forward and backward.

Each load/unload mechanism 200L, 200R further includes a pallet loading/unloading mechanism 7. Each pallet loading/unloading mechanism 7 includes a pallet support mechanism 70L, 70R that supports the pallets. Each pallet support mechanism 70L, 70R has a support claw 71 that supports the flange portion of the side end of the loaded pallet P1 and the empty pallet P2. Each support claw 71 is attached to a chain 73, and by raising and lowering each support claw 71 in unison by the chain 73, the loaded pallet P1 is loaded/unloaded onto the chain conveyor 3 for transporting loads, and the empty pallet P2 is loaded/unloaded onto the chain conveyor 4 for transporting empty pallets.

When lifting the loaded pallet P1 or empty pallet P2 during loading and unloading of each pallet, the chain conveyors 3, 4 for transporting loads and empty pallets become an obstacle and must be removed from the work area S. For this reason, first and second conveyor movement mechanisms are incorporated into each of the left and right load loading/unloading mechanisms 200L, 200R. However, incorporating two conveyor movement mechanisms into each load loading/unloading mechanism 200L, 200R results in a complex structure, which leads to an increase in size and cost of the load loading/unloading device 2.

In order to solve the above problems, the applicant recently proposed a load carrying device 2 with a structure shown in FIG. 13 (see, for example, Patent Document 1). In the load carrying device 2 shown in the figure, movable frames 150L, 150R are provided on each load carrying mechanism 200L, 200R, and a chain conveyor 3 for transporting loads and a chain conveyor 4 for transporting empty pallets are provided in parallel on each movable frame 150L, 150R in parallel on the top and bottom. Each movable frame 150L, 150R swings inward and outward with its upper end as a fulcrum, and this action causes the left and right chain conveyors 3, 4 for transporting loads and empty pallets to move forward and backward simultaneously with respect to the work area S. In the figure, 70L, 70R are pallet support mechanisms for the pallet loading and unloading mechanism 7, and 71 are support claws for supporting the loaded pallet P1 and the empty pallet P2.

Patent No. 3896373

In the load loading/unloading device 2 described in Patent Document 1, the movable frames 150L, 150R swing about a rotation axis provided at the top of the fixed frames 160L, 160R as a fulcrum, and this swinging can cause the fixed frames 160L, 160R to vibrate or sway, which can interfere with the loading and unloading of loaded pallets P1 and empty pallets P2 onto the chain conveyors 3, 4. In order to suppress the vibration and swinging of the fixed frames 160L, 160R, it is necessary to make the fixed frames 160L, 160R robust, but this would result in an increase in size and cost of the device.

In addition, when loading and unloading the loaded pallet P1 onto and from the chain conveyor 3 for transporting cargo, the chain conveyor 3 for transporting cargo can be retreated only the minimum distance required for evacuation, but the chain conveyor 4 for transporting empty pallets must be retreated a greater distance than necessary, requiring a large space for evacuation, and the cargo loading/unloading device 2 becomes larger.

This invention was made with the above-mentioned problems in mind, and aims to provide a pallet-based load-transport device that suppresses vibration and rocking of the fixed frame caused by the forward and backward movement of the movable frame, making it possible to miniaturize the device and reduce costs.

The pallet-utilizing load transport device of the present invention includes a lifting mechanism having a lifting table that moves up and down between multiple floors, and a load loading/unloading device that is installed at the entrance/exit of a specified floor of the lifting mechanism. The lifting table is provided with two upper and lower transport conveyors for horizontally transporting loaded pallets and empty pallets, respectively. The load loading/unloading device consists of left and right load loading/unloading mechanisms that are arranged opposite each other with a working area facing the entrance/exit between them. Each load loading/unloading mechanism includes a load transport chain conveyor that works in conjunction with the upper transport conveyor of the lift table to load and unload loaded pallets onto and from the lift table, a chain conveyor for transporting empty pallets that works in conjunction with the lower transport conveyor of the lift table to load and unload empty pallets onto and from the lift table, a movable frame on which the load transport chain conveyor and the empty pallet transport chain conveyor are arranged parallel to one another on the side facing the working area, a pallet loading/unloading mechanism for loading and unloading loaded pallets onto and from the load transport chain conveyor and the empty pallet transport chain conveyor, and a movable frame movement mechanism that supports the movable frame in an upright position and moves the movable frame forward and backward relative to the working area while maintaining the upright position.

In the above configuration, the desirable form of the "pallet" is one in which vertical side walls are formed on both ends of the horizontal loading surface, and horizontal outward flanges are formed on the upper end of each side wall, but it is not necessarily limited to such a form as long as it is configured to support both ends.

In the pallet-utilizing load transport device configured as described above, at the entrance of a predetermined floor of the lifting mechanism, the load loading/unloading device simultaneously loads and unloads loaded pallets and empty pallets onto and from the lifting table in parallel.
First, the operation of carrying a loaded pallet placed on the floor surface out onto the lift table by the load carrying-in/out device will be described.

First, the loaded pallet is lifted by the pallet loading/unloading mechanism to a position above the chain conveyor for transporting the load (see Figures 7(A) and (B) described below). When the loaded pallet is being lifted, the chain conveyors for transporting the load and empty pallets are retracted from the working area, so that the chain conveyors do not interfere with the lifting of the loaded pallet.

Next, the movable frame is moved by the movable frame moving mechanism while being kept in an upright position, and the chain conveyor for transporting the load and the chain conveyor for transporting the empty pallet are advanced toward the working area. After that, the loaded pallet is lowered onto the chain conveyor for transporting the load (see Figures 8(A) and (B) described later).
During the above-mentioned forward and backward movements of the movable frame, the movable frame moves while maintaining an upright posture, so the fixed frame does not vibrate or swing, and there is no hindrance to loading pallets onto the chain conveyor.

Next, the chain conveyor for transporting the load and the upper transport conveyor of the lift table are linked and driven in the same direction (the direction to transport the load onto the lift table). Meanwhile, the chain conveyor for transporting empty pallets and the lower transport conveyor of the lift table are linked and driven in the same direction (the direction to transport the pallet from the lift table). As a result, the loaded pallet on the chain conveyor for transporting the load is transported onto the upper transport conveyor of the lift table, and at the same time, the empty pallet on the lower transport conveyor of the lift table is transported onto the chain conveyor for transporting empty pallets (see Figure 9 below).

When lowering an empty pallet onto the floor for loading, the empty pallet on the chain conveyor for transporting empty pallets is lifted upward by the pallet loading/unloading mechanism, and then the left and right movable frames are moved by the movable frame movement mechanism while maintaining an upright position, causing the chain conveyor for transporting empty pallets to retreat from the working area, and the lifted empty pallet is lowered onto the floor.

Next, the operation of carrying the loaded pallet on the lift table into the load carrying-in/out device will be described.
First, the upper transport conveyor of the lift table and the chain conveyor for transporting loads are driven in the same direction (the direction in which loads are brought in from the lift table). Meanwhile, the chain conveyor for transporting empty pallets and the transport conveyor below the lift table are driven in the same direction (the direction in which the pallets are transported out onto the lift table). As a result, the loaded pallet on the transport conveyor above the lift table is transported onto the chain conveyor for transporting loads, and at the same time, the empty pallet on the chain conveyor for transporting empty pallets is transported out onto the transport conveyor below the lift table (see FIG. 10(A) described later).

Next, the loaded pallet on the load-transporting chain conveyor is supported and lifted by the pallet loading/unloading mechanism (see Figure 10(B) described below), and then the movable frame is moved by the movable frame moving mechanism to retract the load-transporting chain conveyor and the chain conveyor for transporting empty pallets from the working area, and then the loaded pallet is lowered and placed on the floor surface (see Figure 11(A) described below).
In this case, the chain conveyors for transporting loads and empty pallets are retracted from the working area, so they do not interfere with the lowering of the loaded pallets. The loads on the loaded pallets lowered onto the floor are carried away by a forklift or the like (see FIG. 11(B) described later).

In a preferred embodiment of the present invention, the movable frame movement mechanism comprises a pair of parallel link mechanisms and a reciprocating mechanism, each of which includes a freely swingable parallel link that supports the movable frame while keeping it horizontal, and the parallel links of the parallel link mechanisms are swung together by the reciprocating mechanism to move the movable frame forward and backward relative to the work area.

In this embodiment, when the parallel links of each parallel link mechanism swing together, the movable frame moves forward and backward relative to the work area while maintaining an upright position, and the fixed frame does not vibrate or swing, so there is no hindrance to loading and unloading pallets onto and from the chain conveyor.

The reciprocating mechanism in a preferred embodiment is driven by a motor capable of rotating forward and backward, and includes a crank mechanism that converts the rotational motion of the motor into reciprocating linear motion and transmits it to each parallel link.

In addition, in a preferred embodiment, the movable frame includes a side plate portion on which a chain conveyor for transporting loads and a chain conveyor for transporting empty pallets are provided, and a front plate portion and a rear plate portion that are perpendicular to the side plate portion and face each other, and the front plate portion and the rear plate portion are supported by the parallel links of each parallel link mechanism.

According to this invention, vibration and rocking of the fixed frame caused by the forward and backward movement of the movable frame is suppressed, and there is no risk of impeding the loading and unloading operation of the pallet. In addition, there is no need to make the fixed frame particularly robust to suppress the occurrence of vibration and rocking, and the load loading and unloading device can be made more compact.

1 is a side view of one of the load carrying-in and -out mechanisms of the load carrying-in and -out device as viewed from the work area side. FIG. 11 is a side view of one of the load carrying-in/out mechanisms as viewed from the opposite side to the working area. FIG. FIG. 13 is a front view of the pallet support mechanism of one of the load loading/unloading mechanisms. FIG. 4 is a perspective view showing a configuration of a movable frame moving mechanism. FIG. 4 is a front view showing the configuration of a movable frame moving mechanism. FIG. 2 is a perspective view showing a configuration of a main part of a movable frame moving mechanism. 11 is a front view showing an operation of unloading a load from the load unloading device to the lift table. FIG. 11 is a front view showing an operation of unloading a load from the load unloading device to the lift table. FIG. 11 is a front view showing an operation of unloading a load from the load unloading device to the lift table. FIG. 13 is a front view showing an operation of loading a load from the lift table to the load loading/unloading device. FIG. 13 is a front view showing an operation of loading a load from the lift table to the load loading/unloading device. FIG. FIG. 1 is a perspective view showing a schematic configuration of a load transport device using a pallet. FIG. 1 is a front view showing the configuration of a conventional load conveying device using a pallet.

The load conveying device according to the present invention conveys loads placed on pallets in both horizontal and vertical directions, and the overall configuration of the device is generally the same as that shown in FIG.
The load transport device shown in Fig. 12 includes a lifting mechanism 1 having a lifting table 10 that moves up and down between a plurality of floors, and a load carrying-in/out device 2 installed near entrances G1, G2 on each floor of the lifting mechanism 1. The load carrying-in/out device 2 is capable of carrying a loaded pallet P1 and an empty pallet P2 in and out simultaneously in parallel with respect to the lifting table 10 of the lifting mechanism 1. Fig. 12 shows a two-story lifting mechanism 1, but the load transport device of the present invention can also be implemented with a lifting mechanism 1 that is three or more stories high.

The lift table 10 is raised and lowered by a lift drive device (not shown). The operation of the lift drive device is controlled so that the lift table 10 stops at the entrances G1, G2 on each floor. The lift table 10 is provided with two conveyors, one above the other, a first conveyor 11 for horizontally transporting loaded pallets P1 and a second conveyor 12 for horizontally transporting empty pallets P2 between the loading/unloading device 2 on each floor. The second conveyor 12 is not shown in FIG. 12, but is indicated by a dotted leader line.

The first and second conveyors 11, 12 are each composed of a roller conveyor. A conveyor drive device (not shown) drives each conveyor 11, 12 individually, and each conveyor is driven to rotate in both forward and reverse directions. Note that instead of roller conveyors, chain conveyors can also be used as the first and second conveyors 11, 12.

The pallets used in the load transport device are made of metal and have vertical side walls 16, 16 on both sides of the horizontal loading surface 15, and outward horizontal flanges 17 bent at the upper end of each side wall 16. When the loaded pallet P1 or empty pallet P2 is raised or lowered, the front and rear positions of the left and right flanges 17 are supported by the support claws 71, 71 of the pallet support mechanisms 70L, 70R provided on the left and right load loading/unloading mechanisms 200L, 200R.

The load loading/unloading device 2 installed on each floor is composed of left and right load loading/unloading mechanisms 200L, 200R. The load loading/unloading mechanisms 200L, 200R are arranged opposite each other on both sides of the work area S facing the entrances G1, G2 on each floor of the lifting mechanism 1. The symbol "200L" indicates the load loading/unloading mechanism located on the left side as one faces the entrances G1, G2, and the symbol "200R" indicates the load loading/unloading mechanism located on the right side as one faces the entrances G1, G2. Below, the configuration related to the left load loading/unloading mechanism 200L will be marked with "L" as necessary, and the configuration related to the right load loading/unloading mechanism 200R will be marked with "R" as necessary.

Figures 1 to 3 show the configuration of the right-side load loading/unloading mechanism 200R of the left and right load loading/unloading mechanisms 200L, 200R. The configuration of the right-side load loading/unloading mechanism 200R will be mainly described below, but the configuration of the left-side load loading/unloading mechanism 200L is similar, so illustrations and descriptions will be omitted.

The load loading/unloading mechanism 200R has a fixed frame 20R supported on the floor and a movable frame 21R that moves as a whole. The fixed frame 20R has a rectangular lower frame 24 supported on the floor and a rectangular upper frame 25 located at a predetermined height above the lower frame 24. The lower frame 24 and the upper frame 25 are connected by a vertical frame 26.

The movable frame 21R is supported in an upright position by the movable frame moving mechanism 5 shown in Figures 4 to 6. The movable frame moving mechanism 5 also moves the movable frame 21R forward and backward relative to the working area S while maintaining the upright position. The configuration of the movable frame moving mechanism 5 will be described in detail later.

On the surface of the movable frame 21R facing the working area S (hereinafter referred to as the "inner surface" and the opposite surface referred to as the "outer surface"), a chain conveyor 3 for transporting loads in conjunction with a first conveyor 11 on the upper level of the lifting table 10 to transport loaded pallets P1 to and from the lifting table 10, and a chain conveyor 4 for transporting empty pallets in conjunction with a second conveyor 12 on the lower level of the lifting table 10 to transport empty pallets P2 to and from the lifting table 10 are provided in parallel on two upper and lower levels.

The chain conveyors 3, 4 for transporting loads and empty pallets are located at the same height as the chain conveyors 3, 4 for transporting loads and empty pallets of the movable frame 21L of the other load carrying-in/out mechanism 200L. The chain conveyors 3, 3 for transporting loads of the left and right movable frames 21L, 21R work together to carry in and out the loaded pallet P1, and the chain conveyors 4, 4 for transporting empty pallets work together to carry in and out the empty pallet P2.
The loaded pallet P1 and the empty pallet P2 are supported from below by the outward flanges 17 on both side ends on a pair of left and right chain conveyors 3, 3 for transporting loads and a pair of chain conveyors 4, 4 for transporting empty pallets, and are transported horizontally between each chain conveyor 3, 4 and the first and second conveyors 11, 12 of the lifting table 10.

The movable frame 21R in the illustrated example is formed by bending a metal plate material, and includes a side plate portion 21a facing the working area S, and a front plate portion 21b and a rear plate portion 21c that are perpendicular to the side plate portion 21a and face each other from the front to the rear. The side plate portion 21a faces the side plate portion 21a of the other movable frame 21L across the working area S. On the inner surface of each side plate portion 21a, horizontally elongated chain conveyor boxes 22, 23 are attached horizontally and parallel to each other in two upper and lower tiers. The upper tier chain conveyor box 22 contains an endless chain 30 that constitutes the chain conveyor 3 for transporting loads, and the lower tier chain conveyor box 23 contains an endless chain 40 that constitutes the chain conveyor 4 for transporting empty pallets, with only the upper edge portion that runs horizontally exposed upward.

The chain conveyor 3 for transporting loads is located at a height corresponding to the position of the first conveyor 11 when the lift table 10 is stopped. The chain conveyor 4 for transporting empty pallets is located at a height corresponding to the position of the second conveyor 12 when the lift table 10 is stopped. In this embodiment, the first and second conveyors 11, 12 of the lift table 10 are constructed of roller conveyors, so the height of the upper surface of each conveyor 11, 12 when the lift table 10 is stopped matches the height of the loading surface 15 of the pallet supported by each chain conveyor 3, 4.

The movable frame movement mechanism 5 supports the movable frame 21R in an upright position and moves the movable frame 21R forward and backward relative to the work area S while maintaining the upright position. As shown in Figures 4 to 6, the movable frame movement mechanism 5 is made up of a pair of front and rear parallel link mechanisms 50A, 50B and a reciprocating mechanism 8.

The parallel link mechanism 50A located on the front side (closer to the lifting mechanism 1) includes first parallel links 51a, 51b that are parallel to each other and have the same length, a pair of fixed plates 55a, 55b, and a connecting plate 53, which will be described later. The parallel link mechanism 50B located on the rear side (farther from the lifting mechanism 1) includes second parallel links 52a, 52b that are parallel to each other and have the same length, a pair of fixed plates 56a, 56b, and a connecting plate 54, which will be described later.

The first parallel links 51a, 51b and the second parallel links 52a, 52b support the movable frame 21R so that it can swing freely forward and backward while maintaining a horizontal position. The first and second parallel links 51a, 51b, 52a, 52b are swung together by the reciprocating mechanism 8, so that the movable frame 21R moves forward and backward relative to the working area S while maintaining an upright position.

As shown in FIG. 6, the connecting plate 53 of the front parallel link mechanism 50A is made of a longitudinal metal plate material with a crank-shaped cross section perpendicular to the length direction, and has a vertical upper plate portion 531 and a vertical lower plate portion 532 bent inward relative to the upper plate portion 531. Both ends of the upper plate portion 531 are fixed to the front plate portion 21b of the movable frame 21R by bolts. The upper ends of the first parallel links 51a, 51b are connected to the lower plate portion 532 by pins. Directly below the connecting plate 53, a pair of fixing plates 55a, 55b made of longitudinal metal plate material are arranged in the same direction as the connecting plate 53.

Each of the fixed plates 55a, 55b has an L-shaped cross section perpendicular to the length direction, and each has a horizontal plate portion 551 and a vertical plate portion 552. The horizontal plate portions 552 of each of the fixed plates 55a, 55b are stacked one above the other and fixed integrally to the lower frame 24 of the fixed frame 20R by bolts. The lower ends of the first parallel links 51a, 51b are supported by pins between the parallel vertical plate portions 552, 552.

The connecting plate 54 of the rear parallel link mechanism 50B has the same configuration as the connecting plate 53 of the front parallel link mechanism 50A, and has an upper plate portion 541 and a lower plate portion 542. Both ends of the upper plate portion 541 are fixed to the rear plate portion 21c of the movable frame 21R by bolts, and the upper ends of the second parallel links 52a, 52b are connected to the lower plate portion 542 by pins. Directly below the connecting plate 54, a pair of longitudinal fixing plates 56a, 56b are arranged in the same direction as the connecting plate 54.

Each fixed plate 56a, 56b has the same configuration as the fixed plates 55a, 55b of the front parallel link mechanism 50A, and has a horizontal plate portion 561 and a vertical plate portion 562. The horizontal plate portions 561, 561 stacked one on top of the other are fixed integrally to the lower frame 24 of the fixed frame 20R by bolts, and the lower end portions of the second parallel links 52a, 52b are supported by pins between the parallel vertical plate portions 562, 562.

The lower ends of the first parallel links 51a, 51b are supported by pins on the fixed plates 55a, 55b and the upper ends are connected to the connecting plate 53 by a pin, while the lower ends of the second parallel links 52a, 52b are supported by pins on the fixed plates 56a, 56b and the upper ends are connected to the connecting plate 54 by a pin, so that the movable frame 21R can move forward and backward by swinging in and out while maintaining a horizontal position, i.e., an upright position.

In order to swing the front and rear parallel link mechanisms 50A, 50B together using the reciprocating mechanism 8, the drive side link 51b of the first parallel links 51a, 51b and the drive side link 52b of the second parallel links 52a, 52b are connected together by a drive plate 57b, and the driven side link 51a of the first parallel links 51a, 51b and the driven side link 52a of the second parallel links 52a, 52b are connected together by a driven plate 57a.

The reciprocating mechanism 8 includes a crank mechanism 81 that uses a motor 80 with a reducer capable of forward and reverse rotation as a drive source, and converts the rotational motion of the motor 80 into reciprocating linear motion and transmits it to the parallel link mechanisms 50A and 50B. The motor 80 is fixed on the lower frame 24 of the fixed frame 20R. The crank mechanism 81 is made up of two cranks 82 and 83 connected by a pin. The output shaft 84 of the motor 80 is connected to the center of the length of one of the cranks 83. The open end of the other crank 82 is connected by a pin to a protruding plate portion 85 protruding from the middle of the drive plate 57b so as to be freely rotatable.

As shown in Figures 4 and 5, the plate surface on the open end side of the crank 83 constitutes the detected part 86 of the position detection mechanism 89. The position detection mechanism 89 is for detecting the swing position of the parallel link mechanisms 50A, 50B, i.e., whether the forward and backward movement position of the side plate part 21a of the movable frame 21R has reached the forward and backward limit position, and is composed of the detected part 86 and two detection sensors 87, 88 arranged side by side with a specified distance between them on the lower frame 24.

The first detection sensor 87 detects the detectable portion 86 at the released end of the crank 83, thereby detecting that the side plate portion 21a of the movable frame 21R has advanced to a position near the working area S, i.e., a predetermined forward limit position. The second detection sensor 88 detects the detectable portion 86 at the released end of the crank 83, thereby detecting that the side plate portion 21a of the movable frame 21R has advanced to a position away from the working area S, i.e., to a predetermined backward limit position.
When the first and second detection sensors 87, 88 detect the detected portion 86, the detection output turns on, and a control device (not shown) stops the rotation of the motor 80, causing the movable frame 21R to stop its forward and backward movement.

In this embodiment, the first and second detection sensors 87, 88 are composed of reflective photoelectric sensors, and the detected portion 86 on the open end side of the crank 83 is composed of a reflective surface that reflects light. When the detected portion 86 approaches and faces the first and second detection sensors 87, 88, the light emitted from the light-emitting portion of the photoelectric sensor is reflected by the detected portion 86 and received by the light-receiving portion of the photoelectric sensor, turning on the detection output.

In this embodiment, reflective photoelectric sensors are used as the first and second detection sensors 87, 88, but transmissive photoelectric sensors may also be used. Also, instead of the photoelectric sensors, proximity sensors or the like may be used.
Furthermore, the position detection mechanism 89 can be configured by using a servo motor for the motor 80, or can be configured by connecting a position detector such as a rotary encoder to the motor 80.

Returning to Figures 1 and 2, the chain conveyor 3 for transporting loads is composed of a first conveyor chain 30 and a wheel group consisting of multiple (five in this embodiment) sprocket wheels 32-36. The first conveyor chain 30 is endlessly stretched between the sprocket wheels 32-36 so that the upper edge 30a, which supports and transports the loading pallet P1, runs horizontally in both forward and reverse directions.

The sprocket wheels 32, 33 located at both ends of this wheel group are at the same height and mesh with the first conveyor chain 30. The sprocket wheel 34 located at the center of the middle section is at a lower position than the sprocket wheels 32, 33 at both ends and meshes with the lower side portion 30b that causes the first conveyor chain 30 to return. Two sprocket wheels 35, 36 are located near both sides of the central sprocket wheel 34, which causes the lower side portion 30b of the first conveyor chain 30 to detour toward the sprocket wheel 34.

The central sprocket wheel 34 is driven by a motor 37 capable of rotating in both forward and reverse directions. The forward and reverse rotation of the sprocket wheel 34 causes the upper edge 30a of the first conveyor chain 30 to move in both forward and reverse directions. A highly efficient, general-purpose AC motor with a reducer is used for the motor 37. The motor 37 is attached to the outer surface of the side plate 21a of the movable frame 21R, and the central sprocket wheel 34 is attached to the output shaft of the reducer.

The chain conveyor 4 for transporting empty pallets is composed of a second conveyor chain 40 and multiple (two in this embodiment) sprocket wheels 41, 42. The second conveyor chain 40 is endlessly stretched between the sprocket wheels 41, 42 so that the upper edge 40a, which supports and transports the empty pallet P2, runs horizontally in both forward and reverse directions. The sprocket wheels 41, 42 are located at the same height and mesh with the second conveyor chain 40.

The movable frame 21R is provided with a power transmission mechanism 6 that transmits the driving force of the motor 37 to the second conveyor chain 40. The power transmission mechanism 6 in this embodiment includes a first power transmission sprocket wheel 62 located on the same shaft 61 as the sprocket wheel 35, a second power transmission sprocket wheel 64 located on the same shaft 63 as one of the sprocket wheels 41 that meshes with the second conveyor chain 40, a power transmission chain 65 stretched between the first power transmission sprocket wheel 62 and the second power transmission sprocket wheel 64, and a sprocket wheel 66 that meshes with the chain 65 to provide tension.

The power transmission mechanism 6 transmits driving force to the second conveyor chain 40 so that the second conveyor chain 40 runs in the opposite direction to the first conveyor chain 30. The sprocket wheel 35 that meshes with the first conveyor chain 30 rotates in the opposite direction to the sprocket wheel 34, and the rotational motion is transmitted to the sprocket wheel 41 that meshes with the second conveyor chain 40 by the power transmission chain 65, causing the second conveyor chain 40 to run in the opposite direction to the first conveyor chain 30 in synchronization with the first conveyor chain 30.

It should be noted that the power transmission mechanism 6 is not limited to this embodiment, so long as it transmits power to the second conveyor chain 40 so that the second conveyor chain 40 runs in the opposite direction to the first conveyor chain 30 .
In addition, in the above embodiment, the chain conveyor 3 for transporting loads is driven by a motor 37 and the driving force is transmitted to the chain conveyor 4 for transporting empty pallets, but the chain conveyor 4 for transporting empty pallets may be driven by a motor and the driving force may be transmitted to the chain conveyor 3 for transporting loads.

As shown in Figures 1 to 3, the load loading/unloading mechanism 200R is equipped with a pallet loading/unloading mechanism 7 for loading/unloading a loaded pallet P1 onto the chain conveyor 3 for transporting loads, and for loading/unloading an empty pallet P2 onto the chain conveyors 4, 4 for transporting empty pallets. The load loading/unloading mechanism 200L on the left side (not shown) is also equipped with a similar pallet loading/unloading mechanism 7, and both pallet loading/unloading mechanisms 7, 7 work together to load and unload the loaded pallet P1 and empty pallet P2.

Each pallet loading/unloading mechanism 7 is equipped with a pallet support mechanism 70L, 70R for supporting the left and right flanges 17 of the loaded pallet P1 and empty pallet P2 at the front and rear positions. The pallet support mechanisms 70L, 70R of the left and right load loading/unloading mechanisms 200L, 200R move up and down synchronously at both sides of the work area S.

The configuration of one of the pallet support mechanisms 70R will be described below. The pallet support mechanism 70R includes a pair of support claws 71, 71 that can be engaged and disengaged at the front and rear with the flanges 17 of the loaded pallet P1 and empty pallet P2, lifting and lowering guides 72, 72 for each support claw 71 provided on the fixed frame 20R, and chains 73, 73 that raise and lower each support claw 71 along each lifting and lowering guide 72. Each chain 73 is stretched between upper and lower sprocket wheels 74, 74 provided on the lower frame 24 and upper frame 25 of the fixed frame 20R, and runs in the vertical direction.

The support claw 71 is attached to the lower end of the slide plate 75. The slide plate 75 is attached to the chain 73 via a spring 77 for shock absorption. The support claw 71 moves up and down by rotating the upper and lower sprocket wheels 74, 74 and running the chain 73. The slide plate 75 is provided with a number of guide rollers 76 that roll along the lifting guide 72, and an operating piece (not shown) that operates a limit switch (not shown) located at the lifting stop position of each support claw 71.

A rotating shaft 91 is disposed on the upper frame 25 of the fixed frame 20R, and a sprocket wheel 74 is attached to the rotating shaft 91. The rotating shaft 91 is driven in either forward or reverse direction by a transmission mechanism 9 consisting of a motor 90, a sprocket wheel, a chain, etc. As the sprocket wheel 74 rotates, each support claw 71 moves up and down simultaneously along the lifting guide 72. As the support claws 71 rise, they engage with the flanges 17 of the loaded pallet P1 and the empty pallet P2, supporting the pallets P1 and P2.

Next, the operation of the load conveying device having the above-mentioned configuration will be described with reference to FIGS.
At a given floor of the lifting mechanism 1, the load carrying device 2 carries a loaded pallet P1 and an empty pallet P2 into and out of the lifting table 10 simultaneously in parallel.
First, the operation of unloading a loaded pallet P1 onto the lifting table 10 and loading an empty pallet P2 from the lifting table 10 at the load loading/unloading device 2 on any floor will be described in detail with reference to Figures 7 to 9.

FIG. 7A shows a state in which an empty pallet P2 placed on a floor surface G has been loaded with goods, that is, a loaded pallet P1 is waiting.
In this standby state, in the left and right load carrying-in/out mechanisms 200L, 200R, the support claws 71 of the pallet support mechanisms 70L, 70R of the pallet loading/unloading mechanisms 7 are positioned below the flanges 17 of the loaded pallet P1. In addition, the movable frames 21L, 21R of the left and right load carrying-in/out mechanisms 200L, 200R are retracted, and the chain conveyor 3 for transporting loads and the chain conveyor 4 for transporting empty pallets are retracted outside the working area S.

When the pallet loading/unloading mechanism 7 starts to operate, the support claws 71 of each pallet support mechanism 70L, 70R support the loaded pallet P1 and lift it to a position above the load-transporting chain conveyors 3, 3, as shown in FIG. 7(B). When lifting the loaded pallet P1, the load-transporting chain conveyor 3 and the empty pallet-transporting chain conveyor 4 are retracted outside the working area S, so the chain conveyors 3, 4 do not interfere with the lifting operation of the loaded pallet P1.

Next, as shown in FIG. 8(A), in the left and right load carrying-in/out mechanisms 200L, 200R, the motors 80 of the reciprocating mechanisms 8 are driven synchronously, and the crank mechanisms 81 are extended. As a result, the first parallel links 51a, 51b of the parallel link mechanism 50A and the second parallel links 52a, 52b of the parallel link mechanism 50B swing together toward the working area S. In this case, the connecting plates 53, 54 attached to the front plate 21b and rear plate 21c of each movable frame 21L, 21R swing while maintaining a horizontal position, so that each movable frame 21L, 21R advances while maintaining an upright position, and the chain conveyors 3, 3 for transporting loads are positioned directly below the flange 17 of the loading conveyor P1.

Then, the support claws 71 of each pallet support mechanism 70L, 70R are lowered, and the loading pallet P1 is lowered onto the chain conveyors 3, 3 for transporting loads, as shown in FIG. 8(B). The support claws 71 are further lowered to disengage from the flanges 17 of the loading pallet P1.

Next, in each load loading/unloading mechanism 200L, 200R, when the motors 37 of the load transport chain conveyors 3 are rotated in synchronization, the load transport chain conveyors 3 are driven and the conveyor chains 30 run in the direction to transport the loaded pallet P1. The rotational drive force of each motor 37 is transmitted to the chain conveyor 4 for transporting empty pallets via the power transmission mechanism 6, and the conveyor chains 40 of the chain conveyor 4 for transporting empty pallets run in the direction to transport the empty pallet P2.

The chain conveyor 3 for transporting cargo and the first conveyor 11 of the lifting table 10 are linked, and the first conveyor 11 is driven in a direction to take in cargo from the cargo loading/unloading device 2. In addition, the chain conveyor 4 for transporting empty pallets and the second conveyor 12 of the lifting table 10 are linked, and the second conveyor 12 is driven in a direction to send the empty pallet P2 to the cargo loading/unloading device 2.

Figure 9 shows a state in which a loaded pallet P1 on the chain conveyors 3, 3 for transporting cargo is transported onto the first conveyor 11 of the lifting table 10, and at the same time, an empty pallet P2 on the second conveyor 12 of the lifting table 10 is transported onto the chain conveyors 4, 4 for transporting empty pallets.

Next, the operation of loading a loaded pallet P1 onto the load loading/unloading device 2 from the lifting table 10 of the lifting mechanism 1 and simultaneously unloading an empty pallet P2 onto the lifting table 10 from the load loading/unloading device 2 on any floor will be described in detail with reference to Figures 10 and 11.

Figure 10 (A) shows a state in which a loaded pallet P1 is transported from the lifting table 10 onto the chain conveyors 3, 3 for transporting cargo by linking the first conveyor 11 of the lifting table 10 with the chain conveyors 3, 3 for transporting cargo of the cargo loading/unloading device 2, and at the same time, an empty pallet P2 is transported from the chain conveyors 4, 4 for transporting empty pallets to the lifting table 10 by linking the second conveyor 12 of the lifting table 10 with the chain conveyors 4, 4 for transporting empty pallets.
In this state, the left and right pallet support mechanisms 70L, 70R of the pallet loading/unloading mechanism 7 position the support claws 71 below the flanges 17 of the loading pallet P1.

Figure 10 (B) shows the state in which the left and right pallet support mechanisms 70L, 70R of the pallet loading/unloading mechanism 7 are driven to raise the support claws 71. When raised, the support claws 71 engage with and support the flanges 17 of the loading pallet P1, and further raise the loading pallet P1 above the chain conveyors 3, 3 used for transporting cargo.

Thereafter, in the left and right load carrying-in/out mechanisms 200L, 200R, the motors 80 of the reciprocating mechanisms 8 rotate in the opposite direction to the above, and the crank mechanisms 81 contract. As a result, the first parallel links 51a, 51b of the parallel link mechanisms 50A and the second parallel links 52a, 52b of the parallel link mechanisms 50B at the front and rear positions swing together toward the opposite side of the working area S.
In this case, the connecting plates 53, 54 swing while maintaining a horizontal position, so that each movable frame 21L, 21R retreats while maintaining an upright position, whereby the chain conveyors 3, 3 for transporting loads and the chain conveyors 4, 4 for transporting empty pallets retreat outward from the position directly below the flange 17 of the loading conveyor P1.

Then, the support claws 71 of the pallet support mechanisms 70L and 70R are lowered as shown in FIG. 11(A) to lower the loading pallet P1 onto the floor surface G, and then, as shown in FIG. 11(B), the load is removed from the loading pallet P1 by a forklift.

In the above embodiment, the load is loaded onto an empty pallet P2 placed on the floor G, and the load is removed from the loaded pallet P1 that has been lowered to the floor G. However, it is also possible to load the load while the empty pallet P2 is supported on the chain conveyor 4 for transporting empty pallets, or to remove the load without lowering the loaded pallet P1 to the floor G.

1 Lifting mechanism 10 Lifting table 11 First conveyor (transport conveyor)
12 Second conveyor (transport conveyor)
DESCRIPTION OF SYMBOLS 2 Load carrying-in/out device 3 Chain conveyor for transporting loads 4 Chain conveyor for transporting empty pallets 7 Pallet loading/unloading mechanism 8 Reciprocating mechanism 20L, 20R Fixed frame 21L, 21R Movable frame 21a Side plate portion 21b Front plate portion 21c Rear plate portion 50A, 50B Parallel link mechanism 51a, 51b First parallel link 52a, 52b Second parallel link 80 Motor 81 Crank mechanism 200L, 200R Load carrying-in/out mechanism P1 Loaded pallet P2 Empty pallet G1, G2 Entrance/exit S Working area

Claims (3)

The system includes a lifting mechanism having a lifting table that moves up and down between a plurality of floors, and a load carrying device that is installed at an entrance of a predetermined floor of the lifting mechanism, and the lifting table is provided with two upper and lower transport conveyors for horizontally transporting loaded pallets and empty pallets, respectively;
The load carrying-in/out device includes left and right load carrying-in/out mechanisms facing each other across a work area facing the entrance,
Each of the load carrying-in/out mechanisms is
a chain conveyor for transporting loads, which is linked with the upper stage transport conveyor of the lifting table to transport the loading pallet into and out of the lifting table;
a chain conveyor for conveying an empty pallet, which is linked with a conveying conveyor below the lift table to carry the empty pallet in and out of the lift table;
a fixed frame having a lower frame supported on a floor surface;
a movable frame on which the load conveyor and the empty pallet conveyor are provided in parallel above and below on a surface facing the working area;
a pallet loading/unloading mechanism for loading/unloading a loaded pallet onto/from the chain conveyor for transporting the load and for loading/unloading an empty pallet onto/from the chain conveyor for transporting the empty pallet;
a movable frame moving mechanism that supports the movable frame in an upright position and moves the movable frame forward and backward relative to the working area while maintaining the upright position,
The movable frame moving mechanism consists of a pair of parallel link mechanisms and a reciprocating mechanism provided on the lower frame of the fixed frame, and each of the parallel link mechanisms includes two parallel links (a driving side and a driven side), and a connecting plate attached to the movable frame and connecting the upper ends of each of the parallel links with a pin, and the connecting plate supports the movable frame so that it can swing at each of the front and rear positions while maintaining it horizontal, and the reciprocating mechanism is connected to the parallel link on the driving side so that the parallel links of each parallel link mechanism swing together. This is a pallet-utilizing load transport device. 2. A pallet-based load transport device as described in claim 1, wherein the reciprocating mechanism includes a crank mechanism that uses a motor capable of rotating forward and reverse as a drive source and converts the rotational motion of the motor into reciprocating linear motion and transmits it to each of the parallel links. A pallet-utilizing load transport device as described in claim 1, wherein the movable frame includes a side plate portion on which the chain conveyor for transporting the load and the chain conveyor for transporting the empty pallets are provided, and a front plate portion and a rear plate portion which are opposed to each other and perpendicular to the side plate portion, and the front plate portion and the rear plate portion are supported by the parallel links of each of the parallel link mechanisms.

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