JP2021042020A - Transfer apparatus - Google Patents

Abstract

To provide a transfer apparatus capable of improving workability for moving a first conveyance device to a first region of a floor surface.SOLUTION: A transfer apparatus 2 comprises: lifters 42a, 42b raised/lowered between lower positions and upper positions; a truck 58 moved on a floor surface 16 between a first region 22 of the floor surface 16 in which a load 8 is transferred between the lifters 42a, 42b and a second region 38 of the floor surface 16 which is located outside the first region 22 and in which the load 8 is transferred with a conveyor 6; and a control unit 110 that controls the lifters 42a, 42b. The lifters 42a, 42b include supports 46a, 46b displaced between projection positions projecting toward the load 8 and retreatment positions retreated from the load 8. The control unit 110 controls the positions of the supports 46a, 46b to be switched between the projection positions and the retreatment positions with respect to the lifters 42a, 42b positioned at the lower positions.SELECTED DRAWING: Figure 1

Description

The present invention relates to a transfer device for transferring a load between a first transfer device and a second transfer device.

Transfer devices for transferring luggage between a pallet jack and an external conveyor are known. The transfer device disclosed in Patent Document 1 includes a trolley and a lifter. The trolley has a conveyor inside the trolley, and is configured to be reciprocally movable in a direction approaching the external conveyor and a direction away from the external conveyor. The lifter raises and lowers the claws for loading luggage.

When transferring luggage from a pallet jack to an external conveyor, the lifter first lowers the claws to the floor. In this state, the user advances the handlift toward the claw so that the handlift rides on the claw, unloads the load from the handlift to the claw, and then retracts the handlift from the claw. Next, by raising the claws from the floor surface by the lifter, the luggage is positioned above the height position of the conveyor in the trolley.

Next, after moving the trolley to the lifter side, the claws are lowered by the lifter, so that the luggage is transferred from the claws to the conveyor inside the trolley. Next, after moving the load on the conveyor inside the trolley in a direction approaching the external conveyor, the claws are raised by the lifter. After that, by moving the trolley in a direction approaching the external conveyor, the load is transferred from the trolley inner conveyor to the external conveyor.

Japanese Patent No. 5509833

However, in the above-mentioned conventional transfer device, when the user advances the hand lift toward the claw and when the hand lift is retracted from the claw, the claw becomes a step, which causes a problem that workability is lowered. Occurs.

The present invention is intended to solve the above-mentioned problems, and an object of the present invention is to provide a transfer device capable of improving workability when moving a first transfer device to a first region of a floor surface. It is to be.

In order to achieve the above object, the transfer device according to one aspect of the present invention includes a first transport device that transports a load while moving on a floor surface, and a transport surface for transporting the load surface is the floor surface. A transfer device for transferring the load between the second transfer device formed above the floor, and a lower position for placing the load in the first region of the floor surface. A lifter that moves up and down between an upper position that positions the luggage above the first region of the floor surface, and the first region of the floor surface that delivers the luggage between the lifter and the lifter. A carriage that is located outside the first region and moves the floor surface to and from the second region of the floor surface that delivers the luggage to and from the second transport device. The lifter includes a control unit that controls the lifter, and the lifter has a support unit that is displaced between a protruding position that protrudes toward the luggage and a retracting position that retracts from the luggage. With respect to the lifter located at the lower position, the position of the support portion is controlled to be switched between the protruding position and the retracted position.

According to this aspect, the lifter has a support portion that is displaced between a protruding position that protrudes toward the load and a retracted position that retracts from the load. As a result, the support portion is displaced from the retracted position to the protruding position, and the lifter is raised from the lower position to the upper position while the load is placed on the first region of the floor surface and the lifter is located at the lower position. By doing so, the luggage can be raised from the first area of the floor surface to a predetermined height position. Therefore, the user only needs to place (unload) the load on the first region of the floor surface by the first transport device, so that the first transport device can be smoothly moved to the first region of the floor surface. be able to. As a result, since there is nothing in the first region of the floor surface that hinders the traveling of the first transport device, workability can be improved.

For example, in the transfer device according to one aspect of the present invention, the transfer device further moves in a predetermined direction, which is a direction from one of the first region and the second region of the trolley to the other. A guide mechanism for guiding is provided, and the guide mechanism is attached to a fixing member fixed to the second region of the floor surface, a guide member moving in the predetermined direction with respect to the fixing member, and the carriage. It may be configured to have a guided member provided and guided in the predetermined direction with respect to the guide member.

According to this aspect, the fixing member of the guide mechanism is fixed to the second region of the floor surface, and the guide member of the guide mechanism moves back and forth between the first region and the second region of the floor surface. When unloading the load to the first area of the floor surface by the transport device of 1, the guide mechanism may interfere with the unloading by retracting the guide member to the second area of the floor surface. Absent. Further, when guiding the movement of the trolley, the guide member of the guide mechanism advances to the first region of the floor surface, so that the straightness of the trolley can be ensured.

For example, in the transfer device according to one aspect of the present invention, the guide member has a protruding portion protruding in a direction intersecting the predetermined direction, and the carriage moves in the predetermined direction with respect to the guide member. When doing so, it may be configured to have an abutting portion capable of contacting the protruding portion.

According to this aspect, when the carriage moves in a predetermined direction with respect to the guide member, the contact portion of the carriage abuts on the protruding portion of the guide member, so that the guide member becomes a fixing member while being towed by the carriage. On the other hand, it moves in a predetermined direction. As a result, the guide member can be moved with respect to the fixing member by utilizing the movement of the carriage, so that a dedicated power source for moving the guide member with respect to the fixing member can be omitted.

For example, in the transfer device according to one aspect of the present invention, the transfer device has a fork portion, the luggage has an insertion hole into which the fork portion can be inserted, and the transfer device further comprises. A first sensor that detects that the load is placed in the first region of the floor surface and a second sensor that detects that the fork portion is inserted into the insertion hole. In the control unit, the first sensor detects that the load is placed on the first region of the floor surface, and the second sensor causes the fork portion to be inserted into the insertion hole. When it is not detected that the lifter is inserted into the lifter, the lifter may be configured to be raised from the lower position to the upper position.

According to this aspect, it is possible to suppress a malfunction in which the lifter rises from the lower position to the upper position before the fork portion of the first transport device is pulled out from the insertion hole of the cargo.

For example, in the transfer device according to one aspect of the present invention, the transfer device is further a pair of first stoppers for positioning the luggage in the first region of the floor surface. It is fixed to the first region of the floor surface, and is arranged at intervals in a direction substantially perpendicular to a predetermined direction which is a direction from one of the first region and the second region to the other in the horizontal plane. A pair of the first stoppers and a second stopper for positioning the luggage in the first region of the floor surface, which is fixed to the first region of the floor surface. The second stopper is arranged closer to the second region than the pair of first stoppers in the predetermined direction, and each of the pair of first stoppers is provided. The height from the floor surface may be set to be lower than the height from the floor surface of the second stopper.

According to this aspect, the height of each of the pair of first stoppers from the floor surface is lower than the height of the second stopper from the floor surface, so that the user can use the first transfer device on the floor surface. It is possible to prevent the pair of first stoppers from coming into contact with the load when advancing toward the area 1. Further, since the height of the second stopper from the floor surface is higher than the height of each of the pair of first stoppers from the floor surface, the load can be loaded while the first transport device supports the load. By contacting the stopper of 2, the load can be accurately positioned in a predetermined direction (direction from one of the first region and the second region toward the other).

According to the transfer device according to one aspect of the present invention, workability when moving the first transfer device to the first region of the floor surface can be improved.

It is a perspective view which shows the whole structure of the transfer apparatus which concerns on embodiment. It is a side view which shows the elevating unit of the transfer device which concerns on embodiment. It is a top view which shows the elevating unit of the transfer device which concerns on embodiment. It is a side view which shows the bogie unit of the transfer device which concerns on embodiment in the state which the bogie is moved to the 1st region. It is a side view which shows the bogie unit of the transfer device which concerns on embodiment in the state which the bogie is moved to the 2nd region. It is a top view which shows the bogie unit of the transfer device which concerns on embodiment. It is a block diagram which shows the functional structure of the transfer apparatus which concerns on embodiment. It is a flowchart which shows the operation flow of the transfer apparatus which concerns on embodiment. It is a figure for demonstrating the operation of steps S101 and S106 of the flowchart of FIG. It is a figure for demonstrating the operation of step S106 of the flowchart of FIG. It is a figure for demonstrating the operation of step S106 of the flowchart of FIG. It is a figure for demonstrating the operation of step S107 of the flowchart of FIG. It is a figure for demonstrating the operation of step S108 of the flowchart of FIG. It is a figure for demonstrating the operation of steps S109 and S110 of the flowchart of FIG. It is a figure for demonstrating the operation of steps S111 and S112 of the flowchart of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that all of the embodiments described below show comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, steps, the order of steps, etc. shown in the following embodiments are examples, and are not intended to limit the present invention. Further, among the components in the following embodiments, the components not described in the independent claims will be described as arbitrary components.

(Embodiment)
[1. Overall configuration of transfer device]
First, the overall configuration of the transfer device 2 according to the embodiment will be described with reference to FIG. FIG. 1 is a perspective view showing the overall configuration of the transfer device 2 according to the embodiment. In FIG. 1, the width direction of the transfer device 2 is the X-axis direction, the depth direction of the transfer device 2 is the Y-axis direction, and the height direction of the transfer device 2 is the Z-axis direction.

The transfer device 2 shown in FIG. 1 is a device for transferring the luggage 8 between the hand lift 4 and the conveyor 6.

In the present embodiment, the luggage 8 includes the pallet 10 and the article 12 placed on the upper surface of the pallet 10. The pallet 10 is formed in a substantially rectangular shape in an XY plan view. A pair of insertion holes 14 are formed on each of the four side surfaces of the pallet 10. The pair of insertion holes 14 are arranged at intervals along the longitudinal direction of each side surface of the pallet 10. The article 12 is, for example, a cardboard box or the like in which a product is packed.

The hand lift 4 is an example of a first transport device that transports the luggage 8 while moving on the floor surface 16, and is manually operated by the user. The hand lift 4 has a handle 18 and a pair of fork portions 20. By operating the handle 18, the pair of fork portions 20 moves up and down with respect to the floor surface 16 by flood control. By inserting the pair of fork portions 20 into the pair of insertion holes 14 of the pallet 10 and operating the handle 18 to raise the pair of fork portions 20 with respect to the floor surface 16, the load 8 is scooped from the floor surface 16. can do. Further, by operating the handle 18 to lower the pair of fork portions 20 with respect to the floor surface 16 and pulling out the pair of fork portions 20 from the pair of insertion holes 14 of the pallet 10, the luggage 8 is pulled out from the floor surface 16. It can be unloaded into the first area 22.

The conveyor 6 is an example of a second conveyor device that is installed on the floor surface 16 and conveys the luggage 8, and is composed of, for example, a chain conveyor. The conveyor 6 is formed with a transport surface 24 for transporting the luggage 8 at a height position above the floor surface 16. For convenience of explanation, the conveyor 6 is shown in a simplified manner in FIG.

As shown in FIG. 1, the transfer device 2 includes an elevating unit 26, a bogie unit 28, and a plurality of positioning members 30, 32, 34, 36 (30 to 36).

The elevating unit 26 is a unit for elevating and lowering the luggage 8 in the vertical direction (Z-axis direction) in the first region 22 of the floor surface 16. The elevating unit 26 delivers the luggage 8 to and from the hand lift 4 in a state where the luggage 8 is placed on the first area 22 of the floor surface 16.

The bogie unit 28 moves the floor surface 16 between the first region 22 of the floor surface 16 and the second region 38 of the floor surface 16 located outside the first region 22, so that the luggage 8 Is a unit for transporting the transfer device 2 in the depth direction (Y-axis direction). The first region 22 and the second region 38 of the floor surface 16 are arranged so as to be adjacent to each other in the depth direction of the transfer device 2. When the bogie unit 28 moves to the first region 22 of the floor surface 16, the luggage 8 is delivered to and from the elevating unit 26. Further, when the bogie unit 28 moves to the second region 38 of the floor surface 16, the luggage 8 is delivered to and from the conveyor 6.

The first area 22 is an area in which the luggage 8 is placed by the hand lift 4 and the luggage 8 is lifted and lowered by the elevating unit 26. In the second region 38, the end on the elevating unit 26 side is located outside the first region 22 in the depth direction of the transfer device 2, and the end on the conveyor 6 side is the carriage unit 28 and the conveyor 6. It is an area at a position where the luggage 8 can be delivered between the two.

The plurality of positioning members 30 to 36 are for positioning the luggage 8 in the first region 22 of the floor surface 16 when the luggage 8 is unloaded to the first region 22 of the floor surface 16 by, for example, the hand lift 4. It is a member.

[2. Elevating unit configuration]
The configuration of the elevating unit 26 will be described with reference to FIGS. 1 to 3. FIG. 2 is a side view showing an elevating unit 26 of the transfer device 2 according to the embodiment. FIG. 3 is a plan view showing an elevating unit 26 of the transfer device 2 according to the embodiment.

As shown in FIGS. 1 and 2, the elevating unit 26 has columns 40a and 40b and lifters 42a and 42b.

The columns 40a and 40b are erected in the first region 22 of the floor surface 16 and are arranged at intervals in the width direction (X-axis direction) of the transfer device 2. Lifting motors 44a and 44b for raising and lowering the lifters 42a and 42b are arranged at the upper ends of the columns 40a and 40b, respectively. These elevating motors 44a and 44b are driven synchronously.

The lifters 42a and 42b are supported on the respective side surfaces of the columns 40a and 40b facing each other, and are synchronized along the longitudinal direction (Z-axis direction) of the columns 40a and 40b by the driving force of the elevating motors 44a and 44b. And go up and down. Specifically, the lifters 42a and 42b have a lower position (position shown by a solid line in FIG. 2) on which the luggage 8 is placed on the first region 22 of the floor surface 16 and a first position of the luggage 8 on the floor surface 16. It moves up and down in synchronization with the upper position (the position indicated by the alternate long and short dash line in FIG. 2) positioned above the region 22.

As shown in FIG. 3, the lifter 42a has a pair of support portions 46a for supporting the luggage 8. Each of the pair of support portions 46a is formed, for example, in the shape of an elongated plate. Each of the pair of support portions 46a has a protruding position (position shown by a solid line in FIG. 3) protruding from the lifter 42a and an inside of the lifter 42a, centered on a swivel shaft 48a that is arranged inside the lifter 42a and extends in the vertical direction. It turns (an example of displacement) in synchronization with the retracted position (the position indicated by the alternate long and short dash line in FIG. 3) stored in. With the lifter 42a in the lower position, each of the pair of support portions 46a projects from the retracted position to the protruding position so as to project toward the luggage 8 placed in the first region 22 of the floor surface 16. It is inserted into a pair of insertion holes 14 of the pallet 10 of the luggage 8. From this state, each of the pair of support portions 46a is retracted from the luggage 8 by turning from the protruding position to the retracting position, and is pulled out from the pair of insertion holes 14 of the pallet 10 of the luggage 8.

As shown in FIG. 3, inside the lifter 42a, a swivel motor 50a for swiveling one support portion 46a and a joint rod (not shown) connecting the pair of support portions 46a are arranged. There is. When one support portion 46a is swiveled by the driving force of the swivel motor 50a, the swivel operation of one support portion 46a is transmitted to the other support portion 46a via the joint rod. As a result, the pair of support portions 46a rotate synchronously. As shown in FIG. 3, in the present embodiment, the turning directions of the pair of support portions 46a are opposite to each other, but the direction is not limited to this, and they may be in the same direction.

As shown in FIG. 3, the lifter 42b has a pair of support portions 46b for supporting the luggage 8 like the lifter 42a. Each of the pair of support portions 46b is formed, for example, in the shape of an elongated plate. Each of the pair of support portions 46b has a protruding position (position shown by a solid line in FIG. 3) protruding from the lifter 42b and an inside of the lifter 42b, centered on a swivel shaft 48b that is arranged inside the lifter 42b and extends in the vertical direction. It turns synchronously with the retracted position (the position indicated by the alternate long and short dash line in FIG. 3) stored in. With the lifter 42b in the lower position, each of the pair of support portions 46b is swiveled from the retracted position to the protruding position so as to project toward the luggage 8 placed in the first region 22 of the floor surface 16. It is inserted into a pair of insertion holes 14 of the pallet 10 of the luggage 8. From this state, each of the pair of support portions 46b is retracted from the luggage 8 by turning from the protruding position to the retracting position, and is pulled out from the pair of insertion holes 14 of the pallet 10 of the luggage 8.

As shown in FIG. 3, inside the lifter 42b, similarly to the lifter 42a, a swivel motor 50b for swiveling one support portion 46b and a joint rod connecting the pair of support portions 46b (not shown). ) And are arranged. When one support portion 46b is swiveled by the driving force of the swivel motor 50b, the swivel operation of one support portion 46b is transmitted to the other support portion 46b via the joint rod. As a result, the pair of support portions 46b rotate synchronously. As shown in FIG. 3, in the present embodiment, the turning directions of the pair of support portions 46b are opposite to each other, but the direction is not limited to this, and they may be in the same direction.

The pair of support portions 46a of the lifter 42a are inserted into the pair of insertion holes 14 facing the lifter 42a of the pallet 10, and the pair of support portions 46b of the lifter 42b face each other with the lifter 42b of the pallet 10. The load 8 can be moved up and down by moving the lifters 42a and 42b up and down while they are inserted into the holes 14.

Further, as shown in FIG. 3, the lifters 42a and 42b are provided with synchronization shift sensors 52 for detecting the synchronization shift of the lifts 42a and 42b. The synchronization shift sensor 52 is composed of, for example, a mirror reflection type photo sensor, and has a mirror 54 arranged on the lifter 42a and a photo sensor 56 arranged on the lifter 42b. When the lifters 42a and 42b move up and down in synchronization, the light from the light emitting element of the photo sensor 56 is reflected by the mirror 54 and received by the light receiving element of the photo sensor 56, and the synchronization shift sensor 52 is turned on. On the other hand, when the lifters 42a and 42b are not moved up and down in synchronization due to, for example, one of the lifting motors 44a and 44b failing, the light from the light emitting element of the photo sensor 56 is not reflected by the mirror 54. The light receiving element of the photo sensor 56 does not receive light, and the synchronization shift sensor 52 is turned off. When the synchronization shift sensor 52 is turned off, the lifting of the lifters 42a and 42b is forcibly stopped. In the present embodiment, the synchronization shift sensor 52 is composed of a mirror reflection type photo sensor, but the present invention is not limited to this, and for example, a transmission type photo sensor or the like may be used.

[3. Bogie unit configuration]
The configuration of the bogie unit 28 will be described with reference to FIGS. 1 and 4A to 5. FIG. 4A is a side view showing a carriage unit 28 of the transfer device 2 according to the embodiment in a state where the carriage 58 is moved to the first region 22. FIG. 4B is a side view showing the bogie unit 28 of the transfer device 2 according to the embodiment in a state where the bogie 58 is moved to the second region 38. FIG. 5 is a plan view showing the bogie unit 28 of the transfer device 2 according to the embodiment.

As shown in FIGS. 1 and 4A to 5, the bogie unit 28 has a bogie 58 and a guide mechanism 60.

The trolley 58 is a self-propelled trolley for transporting the loaded luggage 8 by traveling (moving) on the floor surface 16. The carriage 58 travels so as to reciprocate between a position where the luggage 8 is delivered to and from the elevating unit 26 and a position where the luggage 8 is delivered to and from the conveyor 6. The carriage 58 has a carriage body 62, a conveyor unit 64, and a plurality of wheels 66.

The carriage body 62 is for loading the conveyor unit 64 and the luggage 8. The dolly body 62 is formed in a substantially rectangular shape, for example, in an XY plan view.

The conveyor unit 64 is composed of, for example, a chain conveyor, and is supported on the upper surface of the carriage body 62. The conveyor unit 64 is formed with a transport surface 68 for transporting the cargo 8. The height position of the transport surface 68 of the conveyor unit 64 from the floor surface 16 is substantially equal to the height position of the transport surface 24 of the conveyor 6 (see FIG. 1) from the floor surface 16. Further, the transport direction of the load 8 on the transfer surface 68 of the conveyor unit 64 is a direction in which the load 8 is discharged toward the transfer surface 24 of the conveyor 6. The conveyor unit 64 is driven in synchronization with the conveyor 6 when the load 8 is delivered to and from the conveyor 6. For convenience of explanation, the conveyor unit 64 is shown in a simplified manner in FIGS. 1 and 5.

Each of the plurality of wheels 66 is supported at the four corners of the lower surface of the carriage body 62 and is rotatably in contact with the floor surface 16. As shown in FIG. 5, a traveling motor 70 for driving a pair of wheels 66a among the plurality of wheels 66 is arranged on the carriage main body 62. The trolley 58 travels on the floor surface 16 by driving the pair of wheels 66a by the driving force of the traveling motor 70.

The guide mechanism 60 is a carriage 58 of a carriage 58 in a predetermined direction (Y-axis direction), which is a direction from one of the first region 22 and the second region 38 of the floor surface 16 toward the other, that is, in the depth direction of the transfer device 2. It is a mechanism for guiding the movement. The guide mechanism 60 includes a slide rail 72 (an example of a fixing member), a slide frame 74 (an example of a guide member), and a plurality of guide rollers 76a, 76b, 76c, 76d (76a to 76d) (guided members and abutting members). It has an example of a part).

The slide rail 72 is fixed to the second region 38 of the floor surface 16 and extends in an elongated shape along the depth direction of the transfer device 2. The slide rail 72 is arranged only in the second region 38 of the floor surface 16, and is not arranged in the first region 22 of the floor surface 16.

The slide frame 74 is formed in a plate shape extending in a long shape along the depth direction of the transfer device 2. A plurality of slide blocks 78 are fixed on the lower surface of the slide frame 74 on the side of the second region 38 from the central portion in the longitudinal direction of the slide frame 74. Each of the plurality of slide blocks 78 is slidably fitted to the slide rail 72 via rollers (not shown). As a result, the slide frame 74 can move with respect to the slide rail 72 along the depth direction of the transfer device 2.

As shown in FIG. 5, one end of the slide frame 74 (the end on the side closer to the first region 22) protrudes in the horizontal plane (in the XY plane) in a direction intersecting the depth direction of the transfer device 2. A protruding portion 80 is formed. Further, at the other end of the slide frame 74 (the end on the side far from the first region 22), a protruding portion 82 is formed so as to project in a direction intersecting the depth direction of the transfer device 2 in the horizontal plane. ..

As shown in FIGS. 4A to 5, the plurality of guide rollers 76a to 76d are supported on the lower surface of the carriage body 62. Each of the plurality of guide rollers 76a to 76d is supported on the lower surface of the carriage body 62 and is rotatable about a rotation shaft 84 extending in the vertical direction. As shown in FIG. 5, the pair of guide rollers 76a, 76b out of the plurality of guide rollers 76a to 76d are arranged at intervals along the depth direction of the transfer device 2, and are arranged on one side surface of the slide frame 74. Rotatably in contact. Further, the other pair of guide rollers 76c and 76d among the plurality of guide rollers 76a to 76d are arranged at intervals along the depth direction of the transfer device 2 and can be rotated to the other side surface of the slide frame 74. Are in contact. As a result, when the carriage 58 moves with respect to the slide frame 74 in the depth direction of the transfer device 2, the plurality of guide rollers 76a to 76d move in the depth direction of the transfer device 2 with respect to the slide frame 74. Be guided.

As shown in FIG. 4A, when the carriage 58 moves from the second region 38 of the floor surface 16 toward the first region 22 (minus direction of the Y axis), the plurality of guide rollers 76a to 76d are used. , Guided in the depth direction of the transfer device 2 with respect to the slide frame 74. As a result, the carriage 58 moves with respect to the slide frame 74 while being guided in the depth direction of the transfer device 2.

More specifically, the carriage 58 moves from the second region 38 to the first region 22 of the floor surface 16 in a state where the protrusion 80 of the slide frame 74 is located in the second region 38 of the floor surface 16. By moving in the direction toward the guide rollers 76a and 76c, the guide rollers 76a and 76c come into contact with the protruding portion 80 of the slide frame 74. With the guide rollers 76a and 76c in contact with the protrusion 80, the carriage 58 further moves toward the first region 22 of the floor surface 16, so that the carriage 58 moves while pushing the protrusion 80.

As a result, as shown in FIGS. 4A and 5, the slide frame 74 is pulled by the carriage 58 in the direction from the second region 38 of the floor surface 16 toward the first region 22 with respect to the slide rail 72. Moving. As a result, the carriage 58 moves while being guided in the direction from the second region 38 to the first region 22 on the floor surface 16 by the guide mechanism 60, so that the straightness of the carriage 58 can be ensured.

As described above, the plurality of slide blocks 78 are fixed to the lower surface of the slide frame 74 on the second region 38 side of the central portion in the longitudinal direction of the slide frame 74. As a result, as shown in FIG. 4A, when the plurality of slide blocks 78 move to the end of the slide rail 72 on the side closer to the first region 22, the plurality of slide blocks 78 of the slide frame 74 are provided. The non-sided end will be located in the first region 22 of the floor surface 16.

On the other hand, as shown in FIG. 4B, when the carriage 58 moves from the first region 22 of the floor surface 16 toward the second region 38 (plus direction of the Y axis), the plurality of guide rollers 76a to The 76d is guided in the depth direction of the transfer device 2 with respect to the slide frame 74. As a result, the carriage 58 moves with respect to the slide frame 74 while being guided in the depth direction of the transfer device 2.

More specifically, the carriage 58 moves from the first region 22 to the second region 38 of the floor surface 16 in a state where the protrusion 82 of the slide frame 74 is located in the first region 22 of the floor surface 16. By moving in the direction toward the guide rollers 76b and 76d, the guide rollers 76b and 76d come into contact with the protruding portion 82 of the slide frame 74. With the guide rollers 76b and 76d in contact with the protrusion 82, the carriage 58 further moves toward the second region 38 of the floor surface 16, so that the carriage 58 moves while pushing the protrusion 82.

As a result, as shown in FIG. 4B, the slide frame 74 moves in the direction from the first region 22 to the second region 38 of the floor surface 16 with respect to the slide rail 72 while being towed by the carriage 58. As a result, the carriage 58 moves while being guided in the direction from the first region 22 to the second region 38 of the floor surface 16 by the guide mechanism 60, so that the straightness of the carriage 58 can be ensured.

[4. Configuration of multiple positioning members]
The configurations of the plurality of positioning members 30 to 36 will be described with reference to FIGS. 1 and 3. As shown in FIGS. 1 and 3, the plurality of positioning members 30 to 36 are fixed to the first region 22 of the floor surface 16.

Each of the plurality of positioning members 30 to 36 is arranged corresponding to the four corners of the pallet 10 placed in the first region 22 of the floor surface 16. Specifically, of the plurality of positioning members 30 to 36, the pair of positioning members 30 and 32 are arranged on the side far from the second region 38 of the floor surface 16 and are arranged in the horizontal plane in the depth direction of the transfer device 2. They are arranged at intervals in a direction substantially perpendicular to the X-axis direction. The arrangement interval of the pair of positioning members 30 and 32 is substantially equal to the lateral width (width in the X-axis direction) of the pallet 10. Further, among the plurality of positioning members 30 to 36, the pair of positioning members 34, 36 are arranged on the side of the floor surface 16 close to the second region 38, and are arranged in the horizontal plane with respect to the depth direction of the transfer device 2. They are arranged at intervals in a substantially vertical direction. The arrangement interval of the pair of positioning members 34, 36 is substantially equal to the width of the pallet 10.

Inclined surfaces 86 and 88 that are inclined with respect to the vertical direction are formed on the surfaces of the pair of positioning members 30 and 32 that face each other, respectively. Further, first stoppers 90 and 92 projecting in a horizontal plane in a direction substantially perpendicular to the depth direction of the transfer device 2 are formed on the surfaces of the pair of positioning members 30 and 32 facing each other. ing. An inclined surface inclined with respect to the vertical direction is formed on the surface of each of the pair of first stoppers 90 and 92 on the second region 38 side of the floor surface 16. Further, inclined surfaces 94 and 96 that are inclined with respect to the vertical direction are formed on the surfaces of the pair of positioning members 34 and 36 that face each other, respectively.

Further, in relation to the pair of first stoppers 90 and 92, as shown in FIGS. 1 and 3, in the first region 22 of the floor surface 16, the luggage 8 is placed in the first region 22 of the floor surface 16. A second stopper 97 for positioning is fixed in the above. The second stopper 97 is arranged closer to the second region 38 on the floor surface 16 than the pair of first stoppers 90 and 92 in the depth direction of the transfer device 2. The second stopper 97 is arranged at the center of the pair of positioning members 34 and 36. An inclined surface inclined with respect to the vertical direction is formed on the surface of the floor surface 16 of the second stopper 97 opposite to the second region 38. The height of each of the pair of first stoppers 90 and 92 from the floor surface 16 is lower than the height of the second stopper 97 from the floor surface 16.

Further, as shown in FIG. 3, the transfer sensor 98 (first) for detecting that the luggage 8 is placed on the first region 22 of the floor surface 16 is mounted on the pair of positioning members 30 and 32. An example of a sensor) is arranged. The transfer sensor 98 is composed of, for example, a transmissive photo sensor, and has a light receiving element 100 arranged on the positioning member 30 and a light emitting element 102 arranged on the positioning member 32.

When the pallet 10 is placed on the first region 22 of the floor surface 16, the light from the light emitting element 102 is blocked below the insertion hole 14 of the pallet 10 and is not received by the light receiving element 100. In this case, the transfer sensor 98 outputs a first detection signal indicating that the luggage 8 is placed in the first region 22 of the floor surface 16 to the control unit 110 (see FIG. 6 described later). On the other hand, when the luggage 8 is not placed on the first region 22 of the floor surface 16, the light from the light emitting element 102 is received by the light receiving element 100. In this case, the transfer sensor 98 does not output the first detection signal to the control unit 110. In the present embodiment, the transfer sensor 98 is arranged on the pair of positioning members 30 and 32, but the present invention is not limited to this, and the transfer sensor 98 is not limited to this, for example, on an arbitrary member erected in the first region 22 of the floor surface 16. The transfer sensor 98 may be arranged.

Further, as shown in FIG. 3, the pair of positioning members 30 and 32 has a hand lift sensor 104 (third) for detecting that the fork portion 20 of the hand lift 4 is inserted into the insertion hole 14 of the pallet 10. An example of 2 sensors) is arranged. The hand lift sensor 104 is composed of, for example, a transmissive photo sensor, and has a light emitting element 106 arranged on the positioning member 30 and a light receiving element 108 arranged on the positioning member 32. The hand lift sensor 104 is arranged on the floor surface 16 farther from the second region 38 than the transfer sensor 98.

When the fork portion 20 is inserted into the insertion hole 14, the light from the light emitting element 106 passes through the insertion hole 14 on the side surface of the pallet 10 facing the light emitting element 106 and is irradiated to the fork portion 20. At this time, the light from the light emitting element 106 is blocked by the fork portion 20 and is not received by the light receiving element 108. In this case, the hand lift sensor 104 outputs a second detection signal indicating that the fork unit 20 is inserted into the insertion hole 14 to the control unit 110. On the other hand, when the fork portion 20 is not inserted into the insertion hole 14, the light from the light emitting element 106 passes through the insertion hole 14 on the side surface of the pallet 10 facing the light emitting element 106 and is received by the light receiving element 108. To. In this case, the hand lift sensor 104 does not output the second detection signal to the control unit 110.

In the present embodiment, the hand lift sensor 104 is arranged on the pair of positioning members 30 and 32, but the present invention is not limited to this, and any method can be used as long as it can be detected that the fork portion 20 is inserted into the insertion hole 14. It may be placed in a position.

[5. Functional configuration of transfer device]
The functional configuration of the transfer device 2 according to the embodiment will be described with reference to FIG. FIG. 6 is a block diagram showing a functional configuration of the transfer device 2 according to the embodiment.

As shown in FIG. 6, the transfer device 2 includes a control unit 110. The control unit 110 controls the elevating motors 44a and 44b of the elevating unit 26 based on the detection results of the transfer sensor 98 and the hand lift sensor 104, respectively.

Specifically, the control unit 110 receives the first detection signal from the transfer sensor 98 and the second detection signal from the hand lift sensor 104 in a state where the lifters 42a and 42b of the elevating unit 26 are in the lower position. When both are received, the lifters 42a and 42b are held in the lower position.

After that, when the control unit 110 receives the first detection signal from the transfer sensor 98 and no longer receives the second detection signal from the hand lift sensor 104, the control unit 110 lowers the lifters 42a and 42b. Raise from position to upper position.

As a result, when the load 8 is unloaded to the first region 22 of the floor surface 16 by the hand lift 4, the pair of fork portions 20 of the hand lift 4 are before being pulled out from the pair of insertion holes 14 of the pallet 10, respectively. It is possible to suppress a malfunction in which the lifters 42a and 42b rise from the lower position to the upper position.

Further, the control unit 110 controls the swivel motors 50a and 50b to set the respective positions of the pair of support portions 46a of the lifter 42a and the pair of support portions 46b of the lifter 42b between the protruding position and the retracted position. Control to switch with.

Further, the control unit 110 controls the traveling motor 70 of the bogie unit 28 based on the detection results of the transfer sensor 98 and the hand lift sensor 104. Specifically, the control unit 110 controls the start timing, stop timing, moving direction, and the like of the bogie 58 of the bogie unit 28. Further, the control unit 110 controls the drive timing, the transport direction, and the like of the conveyor unit 64 of the bogie 58 of the bogie unit 28.

[6. Operation of transfer device]
The operation of the transfer device 2 according to the embodiment will be described with reference to FIGS. 7 to 13. FIG. 7 is a flowchart showing an operation flow of the transfer device 2 according to the embodiment. FIG. 8 is a diagram for explaining the operation of steps S101 and S106 in the flowchart of FIG. 7. 9A and 9B are diagrams for explaining the operation of step S106 in the flowchart of FIG. 7. FIG. 10 is a diagram for explaining the operation of step S107 in the flowchart of FIG. 7. FIG. 11 is a diagram for explaining the operation of step S108 in the flowchart of FIG. 7. FIG. 12 is a diagram for explaining the operation of steps S109 and S110 in the flowchart of FIG. 7. FIG. 13 is a diagram for explaining the operation of steps S111 and S112 in the flowchart of FIG. 7.

Hereinafter, the operation of the transfer device 2 when the load 8 is transferred from the hand lift 4 to the conveyor 6 will be described. Further, in the following, the overall flow of the operation of the transfer device 2 will be described with reference to FIG. 7, and the operation of each step of the flowchart of FIG. 7 will be described with reference to FIGS. 8 to 13.

Before transferring the load 8 from the hand lift 4 to the conveyor 6, each of the lifters 42a and 42b is held at a lower position, and the pair of support portions 46a of the lifter 42a and the pair of support portions 46b of the lifter 42b. Each of them is held in the retracted position. Further, the carriage 58 is on standby in the second region 38 of the floor surface 16, and the drive of the conveyor unit 64 of the carriage 58 is stopped.

As shown in FIG. 8A, first, the user advances the hand lift 4 that has scooped the cargo 8 toward the first region 22 of the floor surface 16 to move the cargo 8 onto the floor surface 16. Transport to the first region 22.

As shown in FIG. 8B, the user operates the handle 18 to lower the pair of fork portions 20 with respect to the floor surface 16 and unload the luggage 8 into the first region 22 of the floor surface 16. (S101 in FIG. 7). At this time, the transfer sensor 98 outputs the first detection signal to the control unit 110, and the hand lift sensor 104 outputs the second detection signal to the control unit 110 (S102 in FIG. 7).

When the luggage 8 is unloaded to the first region 22 of the floor surface 16 by the hand lift 4, the four corners of the pallet 10 come into contact with the plurality of positioning members 30 to 36, respectively, so that the width of the transfer device 2 is widened. In the direction (X-axis direction), the pallet 10 (load 8) is positioned in the first region 22 of the floor surface 16. At the time of this unloading, even if the position of the pallet 10 deviates from the mounting area defined inside the plurality of positioning members 30 to 36, the pallet 10 is each of the plurality of positioning members 30 to 36. By sliding down at least one of the inclined surfaces 86, 88, 94, 96 of the pallet 10, the position of the pallet 10 can be guided to the above-mentioned placement region.

Further, when the luggage 8 is unloaded to the first region 22 of the floor surface 16 by the hand lift 4, both ends on one side surface of the pallet 10 (the side surface of the floor surface 16 far from the second region 38) are formed. The pair of first stoppers 90 and 92 are in contact with each other, and the central portion of the other side surface of the pallet 10 (the side surface of the floor surface 16 closer to the second region 38) is in contact with the second stopper 97. As a result, the pallet 10 is positioned in the first region 22 of the floor surface 16 in the depth direction of the transfer device 2.

As described above, the height of the pair of first stoppers 90 and 92 from the floor surface 16 is lower than the height of the second stopper 97 from the floor surface 16, so that the user can use the hand lift 4 Can be prevented from coming into contact with the pallet 10 when the pair of first stoppers 90 and 92 are advanced toward the first region 22 of the floor surface 16. Further, since the height of the second stopper 97 from the floor surface 16 is higher than the height of the pair of first stoppers 90 and 92 from the floor surface 16 of each, the hand lift 4 supports the luggage 8. By bringing the pallet 10 into contact with the second stopper 97, the load 8 can be accurately positioned in the depth direction of the transfer device 2.

As a result, as will be described later, the pair of support portions 46a of the lifter 42a can be accurately inserted into the pair of insertion holes 14 facing the lifter 42a of the pallet 10, and the pair of support portions 46b of the lifter 42b can be inserted. It can be accurately inserted into the pair of insertion holes 14 facing the lifter 42b of the pallet 10, respectively.

When the user has not retracted the pallet jack 4 from the first region 22 of the floor surface 16 (NO in S103 of FIG. 7), the control unit 110 holds the lifters 42a and 42b in the lower position (FIG. 7). S104), the process returns to step S102 described above.

As shown in FIG. 8B, the user pulled out the pair of fork portions 20 from the pair of insertion holes 14 of the pallet 10, respectively, so that the hand lift 4 was retracted from the first region 22 of the floor surface 16. In that case (YES in S103 of FIG. 7), the output of the second detection signal from the hand lift sensor 104 is stopped (S105 of FIG. 7).

As shown in FIG. 8B, the front side surface of the pallet 10 (lower side in the paper surface in FIG. 8) is in contact with the stopper 90 of the positioning member 30 and the stopper 92 of the positioning member 32. As a result, the pallet 10 (luggage 8) is moved toward the front side (minus side of the Y-axis) from the above-described placement area by the momentum when the pair of fork portions 20 of the hand lift 4 are pulled out from the pair of insertion holes 14 of the pallet 10, respectively. ) Can be suppressed.

In response to the fact that the control unit 110 no longer receives the second detection signal from the hand lift sensor 104, the control unit 110 moves each of the pair of support portions 46a of the lifter 42a and the pair of support portions 46b of the lifter 42b from the retracted position. It is swiveled to a protruding position (S106 in FIG. 7).

As shown in FIG. 9A, each of the pair of support portions 46a of the lifter 42a is inserted into the pair of insertion holes 14 facing the lifter 42a of the pallet 10 by turning from the retracted position to the protruding position. Further, as shown in FIG. 9B, each of the pair of support portions 46b of the lifter 42b is inserted into the pair of insertion holes 14 facing the lifter 42b of the pallet 10 by turning from the retracted position to the protruding position. As a result, the luggage 8 is delivered between the hand lift 4 and the lifters 42a and 42b with the lifters 42a and 42b at lower positions.

As shown in FIGS. 10A and 10B, the control unit 110 raises the lifters 42a and 42b from the lower position to the upper position (S107 in FIG. 7). The pair of support portions 46a of the lifter 42a are inserted into the pair of insertion holes 14 facing the lifter 42a of the pallet 10, and the pair of support portions 46b of the lifter 42b face each other with the lifter 42b of the pallet 10. By raising the lifters 42a and 42b from the lower position to the upper position while being inserted into the holes 14, the luggage 8 is lifted from the floor surface 16 to a predetermined height position by the lifters 42a and 42b. At this time, the height position of the lower surface of the luggage 8 from the floor surface 16 is higher than the height position of the transport surface 68 of the conveyor unit 64 of the carriage 58 from the floor surface 16.

As shown in FIGS. 11A and 11B, the control unit 110 moves the carriage 58 from the second region 38 of the floor surface 16 to the first region 22 (S108 in FIG. 7). As a result, the carriage 58 is located directly below the luggage 8 lifted above the first region 22 of the floor surface 16 by the lifters 42a and 42b.

As shown in FIGS. 12A and 12B, the control unit 110 lowers the lifters 42a and 42b from the upper position to the intermediate position (S109 in FIG. 7). The intermediate position is a position between the upper position and the lower position, and more specifically, a position where the luggage 8 is placed on the transport surface 68 of the conveyor unit 64 of the carriage 58. As a result, as shown in FIG. 12B, the luggage 8 is placed on the transport surface 68 of the conveyor unit 64 of the carriage 58, and the luggage 8 is delivered between the lifters 42a and 42b and the carriage 58. ..

As shown in FIG. 12B, the control unit 110 holds each of the pair of support portions 46a of the lifter 42a and the pair of support portions 46b of the lifter 42b in a state where the lifters 42a and 42b are positioned at intermediate positions. , Turn from the protruding position to the retracted position (S110 in FIG. 7). As a result, the pair of support portions 46a of the lifter 42a are pulled out from the pair of insertion holes 14 facing the lifter 42a of the pallet 10, respectively. Further, each of the pair of support portions 46b of the lifter 42b is pulled out from the pair of insertion holes 14 facing the lifter 42b of the pallet 10.

As shown in FIGS. 13A and 13B, the control unit 110 moves the carriage 58 from the first region 22 of the floor surface 16 to the second region 38 (S111 in FIG. 7), and the carriage 58. Is stopped in the second region 38. As a result, the conveyor unit 64 of the carriage 58 is arranged at a position adjacent to the conveyor 6 to which the luggage 8 is transferred. As shown in FIG. 13 (b), the control unit 110 drives the conveyor unit 64 of the carriage 58 to transport the luggage 8 from the conveyor unit 64's conveyor surface 68 toward the conveyor 6's conveyor unit 24. Will be done. As a result, the luggage 8 is delivered between the carriage 58 and the conveyor 6.

As described above, the transfer of the luggage 8 from the hand lift 4 to the conveyor 6 is completed. The operation of the transfer device 2 when the load 8 is transferred from the conveyor 6 to the hand lift 4 may be the reverse operation of the operation of the transfer device 2 described above.

[7. effect]
As described above, the lifters 42a and 42b each have a pair of support portions 46a and a pair of support portions 46b that swivel between a protruding position protruding toward the luggage 8 and a retracting position retracting from the luggage 8. ing. As a result, the pair of support portions 46a and the pair of support portions 46b are swiveled from the retracted position to the protruding position while the luggage 8 is placed on the first region 22 of the floor surface 16, and the lifters 42a and 42b are lowered. By ascending from the position to the upper position, the luggage 8 can be raised from the first region 22 of the floor surface 16 to a predetermined height position.

Therefore, since the user only needs to place (unload) the luggage 8 on the first area 22 of the floor surface 16 by the hand lift 4, the hand lift 4 can be smoothly moved to the first area 22 of the floor surface 16. Can be made to. As a result, since there is nothing in the first region 22 of the floor surface 16 that hinders the running of the hand lift 4, workability can be improved.

(Modification example, etc.)
Although the transfer device of the present invention has been described above based on the embodiment, the present invention is not limited to the above embodiment. The present invention also includes a form obtained by subjecting a person skilled in the art to a modification of the above embodiment, and another form realized by arbitrarily combining the components of the above embodiment.

In the above embodiment, the first transport device is configured by the hand lift 4, but the present invention is not limited to this, and may be configured by, for example, a forklift or an automated guided vehicle (AGV). When the package 8 cannot be directly delivered from the first transport device to the second transport device, the load 8 can be delivered to the second transport device by using the transfer device 2 of the present invention.

Further, in the above embodiment, the second transfer device is composed of the conveyor 6, but the present invention is not limited to this, and for example, a tracked carriage, a trackless carriage, a stacker crane, or the like may be used. When the second transfer device is composed of, for example, a stacker crane, the conveyor unit 64 may be omitted from the bogie unit 28.

Further, in the above embodiment, the slide frame 74 is moved with respect to the slide rail 72 by using the movement of the carriage 58, but the present invention is not limited to this, and for example, the sly frame 74 is moved with respect to the slide rail 72. A dedicated power source may be provided for this purpose.

Further, in the above embodiment, each of the pair of support portions 46a and the pair of support portions 46b is configured to rotate between the projecting position and the retracting position, but the present invention is not limited to this, and for example, the projecting position and the retracting position and the retracting position. It may be configured to reciprocate linearly with the position (an example of displacement).

Further, in the above embodiment, the guided member and the abutting portion are composed of the same member (guide rollers 76a to 76d), but the present invention is not limited to this, and the guided member and the abutting portion are composed of separate members. You may.

Further, in the above embodiment, the protrusions 80 and 82 are formed at both ends of the slide frame 74 in the longitudinal direction, respectively, but the present invention is not limited to this, and for example, one protrusion is formed at the center of the slide frame 74 in the longitudinal direction. Only one may be formed.

Further, in the above embodiment, the projecting portions 80 and 82 are projected in the direction intersecting the depth direction of the transfer device 2 in the horizontal plane, but the present invention is not limited to this, and the projecting portions 80 and 82 may be projected in the vertical direction, for example. ..

The present invention can be applied to, for example, a transfer device for transferring a load between a hand lift and a conveyor.

2 Transfer device 4 Hand lift (first transfer device)
6 Conveyor (second conveyor)
8 Luggage 10 Pallet 12 Article 14 Insertion hole 16 Floor surface 18 Handle 20 Fork part 22 First area 24 Transport surface 26 Elevating unit 28 Bogie unit 30, 32, 34, 36 Positioning member 38 Second area 40a, 40b Strut 42a , 42b Lifters 44a, 44b Lifting motors 46a, 46b Supports 48a, 48b Swing shafts 50a, 50b Swing motors 52 Synchronous sensor 54 Mirror 56 Photosensor 58 Bogie 60 Guide mechanism 62 Bogie body 64 Conveyor unit 66, 66a Wheels 68 Conveyor surface 70 Traveling motor 72 Slide rail (fixing member)
74 Slide frame (guide member)
76a, 76b, 76c, 76d Guide roller (guided member, contact part)
78 Slide block 80, 82 Protruding part 84 Rotating shaft 86, 88, 94, 96 Inclined surface 90, 92 First stopper 97 Second stopper 98 Transfer sensor (first sensor)
104 Hand lift sensor (second sensor)
100,108 Light receiving element 102, 106 Light emitting element 110 Control unit

Claims (5)

The load is transferred between a first transport device that transports the load while moving on the floor surface and a second transfer device in which the transport surface for transporting the load is formed above the floor surface. It is a transfer device for mounting,
A lifter that moves up and down between a lower position where the luggage is placed on the first region of the floor surface and an upper position where the luggage is positioned above the first region of the floor surface.
The luggage is delivered between the first region of the floor surface where the luggage is delivered to and from the lifter, and the luggage is delivered between the first region and the second transport device located outside the first region. A dolly that moves the floor surface to and from a second region of the floor surface,
A control unit that controls the lifter is provided.
The lifter has a support portion that is displaced between a protruding position that protrudes toward the luggage and a retracting position that retracts from the luggage.
The control unit is a transfer device that controls the lifter located at the lower position so that the position of the support portion is switched between the projecting position and the retracting position. The transfer device further includes a guide mechanism for guiding the movement of the carriage in a predetermined direction, which is a direction from one of the first region and the second region to the other.
The guide mechanism is
A fixing member fixed to the second region of the floor surface and
A guide member that moves in the predetermined direction with respect to the fixing member, and
The transfer device according to claim 1, further comprising a guided member provided on the carriage and guided in the predetermined direction with respect to the guide member. The guide member has a protruding portion that protrudes in a direction intersecting the predetermined direction.
The transfer device according to claim 2, wherein the carriage has an abutting portion capable of contacting the protruding portion when moving in the predetermined direction with respect to the guide member. The transport device has a fork portion and has a fork portion.
The luggage has an insertion hole into which the fork portion can be inserted.
The transfer device further
A first sensor that detects that the load has been placed in the first area of the floor surface, and
A second sensor for detecting that the fork portion is inserted into the insertion hole is provided.
The control unit detects that the load is placed in the first region of the floor surface by the first sensor, and the fork portion is inserted into the insertion hole by the second sensor. The transfer device according to any one of claims 1 to 3, wherein the lifter is raised from the lower position to the upper position when it is not detected. The transfer device further
A pair of first stoppers for positioning the load in the first region of the floor surface, fixed to the first region of the floor surface, and the first region and the said in a horizontal plane. A pair of first stoppers arranged at intervals in a direction substantially perpendicular to a predetermined direction, which is a direction from one of the second regions to the other,
A second stopper for positioning the load in the first region of the floor surface, and a second stopper fixed to the first region of the floor surface, is provided.
In the predetermined direction, the second stopper is arranged closer to the second region than the pair of first stoppers.
The transfer device according to any one of claims 1 to 4, wherein the height of each of the pair of first stoppers from the floor surface is lower than the height of the second stopper from the floor surface. ..

Images