JP7738928B2 - Transport vehicle - Google Patents

Description

The present invention relates to a transport vehicle.

Patent Document 1 discloses a low lift.

This low-lift truck will now be explained. It comprises a drive unit equipped with a single-acting cylinder device, a base connected via a lift arm, forks that extend forward and are inserted into a cargo-carrying pallet, and load wheels that are attached to the tips of the forks in a raised and lowered manner and connected to the lift arm via a push rod. The lift arm rotates as the cylinder device moves up and down, raising and lowering the forks. Auxiliary wheels are provided near the base ends of the forks at the bottom of the base, which touch the ground as the base descends. After touching the ground, the push rod is pulled toward the lift arm, retracting the load wheels inside the forks. A coil spring is provided between the forks and the push rod as a biasing means.

Japanese Patent Application Publication No. 08-113145

In the low-lift truck disclosed in Patent Document 1, the road wheels located at the front ends of the forks are automatically stored inside the forks when the forks are lowered. Therefore, when the forks are inserted into a pallet, the road wheels do not interfere with the boards on the road side of the pallet, preventing impact to the low-lift truck when inserted into the pallet. However, when the low-lift truck is driven after transporting a pallet, the weight of the entire fork is placed on the training wheels, which could increase the failure rate of parts around the training wheels.

In consideration of the above circumstances, the present invention aims to provide a transport vehicle that can prevent impacts on the transport vehicle when inserting the pallet, and that can reduce localized increases in load when the vehicle is driven after transporting the pallet.

One aspect of the present invention provides a transport vehicle. The transport vehicle includes a vehicle body, a base unit, a fork, and a lifting unit. The vehicle body has rear running wheels and is configured to move the entire transport vehicle in response to the movement of the rear running wheels. The base unit is supported on the vehicle body. The fork is connected to the base unit and extends horizontally. The lifting unit is connected to the base unit and is configured to raise and lower the base unit and fork. The fork has a front running wheel and an intermediate wheel. The front running wheel is located at the front end, which is the end opposite the base unit. The intermediate wheel is located at the rear end, which is the end connected to the base unit, or at an intermediate portion between the front and rear ends. The lifting unit is configured to act on the base unit when the intermediate wheel is in contact with the ground. The fork tilts, using the intermediate wheel as a fulcrum, so that the front running wheel lifts off the ground surface due to the action of the lifting unit.

This configuration reduces the impact on the transport vehicle when inserting the pallet, and also reduces localized increases in load when the pallet is moved after being transported.

FIG. 1 is a diagram showing the configuration of a pallet truck 100. FIG. 2 is a top perspective view of the pallet 200. FIG. 2 is a bottom perspective view of the pallet 200. 2 is a diagram showing a state in which the position of the fork 130 is lowered from the state in FIG. 1 . 5 is a diagram showing a state in which the fork 130 is tilted from the state shown in FIG. 4. FIG. 6 is a diagram showing a state in which the fork 130 is further tilted from the state in FIG. 5 . 10 is a diagram showing the state before the inclined fork 130 is inserted into the pallet 200. FIG. 10 is a diagram showing a state in which the inclined fork 130 is inserted halfway into the pallet 200. FIG. 10 is a diagram showing a state in which the inclined fork 130 is inserted deep into the pallet 200. FIG.

Embodiments of the present invention will be described below using the drawings. The various features shown in the following embodiments can be combined with each other.

1. Configuration of Pallet Truck 100 In Section 1, the configuration of the pallet truck 100 used in this embodiment will be described.

1-1. Pallet truck 100
FIG. 1 is a diagram showing the configuration of a pallet truck 100. The pallet truck 100 is an example of a "transport vehicle" in the claims. The pallet truck 100 includes a vehicle body 110, a base unit 120, forks 130, a double-acting cylinder 140 (an example of a "lifting unit" in the claims), and a link mechanism 150. These components will be further described. Here, the pallet truck 100 is assumed to be an unmanned vehicle that receives control signals via a communication unit (not shown) and operates based on the control signals.

1-2. Vehicle body 110
The vehicle body 110 is the housing of the pallet truck 100. The vehicle body 110 has Mecanum wheels 111 (an example of "rear wheels for driving" in the claims) and is configured to move the entire pallet truck 100 in accordance with the operation of the Mecanum wheels 111. The vehicle body 110 houses a control device that controls the double-acting cylinder 140 and the Mecanum wheels 111, a battery, etc. The vehicle body 110 is made of steel. The vehicle body 110 is formed in a box shape.

1-3. Base part 120
The base part 120 is supported on the side of the vehicle body 110 indicated by the arrow 160. The base part 120 supports the fork 130, the double-acting cylinder 140, and the first link part 151 of the link mechanism 150. The base part 120 is made of steel. The base part 120 is composed of a lower part formed in the shape of a rectangular parallelepiped and an upper part extending from the lower part in the direction of the arrow 170.

1-4. Fork 130
The forks 130 are connected to the lower part of the base 120. When the forks 130 are inserted into the insertion openings 240 of the pallet 200, they can move from a lowered state to an elevated state, thereby lifting the pallet 200. In other words, the forks 130 are configured so that cargo loaded on the pallet 200 can be placed on the forks via the pallet 200. The forks 130 are made of steel. The forks 130 are formed so that each of the forks extends horizontally in the direction of the arrow 160, with the lower part of the base 120 as the base point. The forks 130 are formed hollow.

The fork 130 has a front wheel 131 for running and an intermediate wheel 133. These components will be described further below.

The front running wheel 131 is located at the front end, which is the end opposite the base 120. In other words, the front running wheel 131 is located at the front end, which is the end of the fork 130 on the side indicated by arrow 160. The front running wheel 131 is a dual-wheel swivel caster. The front running wheel 131 is attached to a caster base 132. Because swivel casters have superior turning performance compared to unidirectional casters, they can be combined with omnidirectional wheels to achieve flexible running.

The intermediate wheel 133 is fixed to the rear end, which is the end connected to the base 120. That is, the intermediate wheel 133 is fixed to the rear end, which is the end of the fork 130 on the side indicated by the arrow 170. The intermediate wheel 133 is a screw-in caster. Because the intermediate wheel 133 is fixed to the fork 130, its relative position to the fork 130 does not change even when the fork 130 moves or when a load is applied to the intermediate wheel 133, and its position in the height direction can be changed by screwing it in. This screwing operation may be manual or automatic. This configuration can prevent interference between the rear end of the fork 130 and the ground when the fork 130 is tilted, depending on the type of pallet 200.

1-5. Double-acting cylinder 140
The double-acting cylinder 140 is connected to the base 120. More specifically, the double-acting cylinder 140 is connected to a connection 141 of the base 120 and a connection 154 of the link mechanism 150. The double-acting cylinder 140 operates such that the piston rod 142 is drawn into the tube 143 when oil is supplied to the rod side, and the piston rod 142 is pushed out of the tube 143 when oil is supplied to the cap side. Therefore, the double-acting cylinder 140 lowers the fork 130 when oil is supplied to the rod side, and raises the fork 130 when oil is supplied to the cap side. In this way, the double-acting cylinder 140 is configured to raise and lower the base 120 and the fork 130.

1-6. Link mechanism 150
The link mechanism 150 is disposed between the base 120 and the front running wheels 131. The link mechanism 150 is configured to move the front running wheels 131 into the interior of the forks 130 when the forks 130 are tilted. This configuration can prevent interference between the front running wheels 131 and the bottom board 230 of the pallet 200. The movement of the front running wheels 131 will be described later.

The link mechanism 150 includes a first link portion 151, a second link portion 152, and a third link portion 153. These components will be described further below.

The first link portion 151 is L-shaped. The first link portion 151 is swingably supported on the vehicle body 110 at the connection portion 154. The first link portion 151 has a swing fulcrum 155 at the bend of the L shape. The first link portion 151 is swingably supported on the base portion 120 at the swing fulcrum 155.

The second link portion 152 is rod-shaped. The second link portion 152 is disposed inside the fork 130. The second link portion 152 is connected to the first link portion 151 at the connection portion 156. The second link portion 152 is configured to be slidable in a direction approximately parallel to the fork 130.

The third link portion 153 has a triangular shape. The third link portion 153 is connected to the second link portion 152 at a connection portion 158 located at a corner of the third link portion 153. The third link portion 153 has a swing fulcrum 157 located at another corner of the third link portion 153. The third link portion 153 is swingably supported on the front end of the fork 130 at the swing fulcrum 157. The third link portion 153 is connected to the caster base 132 at a connection portion 159 located at the remaining corner of the third link portion 153. In other words, the front running wheel 131 is connected to the third link portion 153.

2. Configuration of Pallet 200 In Section 2, the configuration of the pallet 200 used in this embodiment will be described.

Figure 2 is a top perspective view of pallet 200. Figure 3 is a bottom perspective view of pallet 200. Pallet 200 has three girders 210, multiple top boards 220, multiple bottom boards 230, and two insertion slots 240.

The girders 210 are placed on both sides and in the center of the pallet 200. The girders 210 form the skeleton of the pallet 200. The girders 210 are formed in a rectangular parallelepiped shape.

The flat boards 220 are arranged on the flat side of the pallet 200 at predetermined intervals in a direction perpendicular to the girders 210. Multiple flat boards 220 can serve as surfaces on which cargo can be placed. The flat boards 220 are formed in a plate shape.

The bottom boards 230 are arranged on the bottom side of the pallet 200 at predetermined intervals in a direction perpendicular to the girders 210. The multiple bottom boards 230 form the contact surface of the pallet 200. The bottom boards 230 are formed in a plate shape.

The insertion port 240 is a space formed by the spar 210, the flat board 220, and the bottom board 230. The two insertion ports 240 function as insertion ports for each of the two prongs 130.

3. Operation of Pallet Truck 100 In Section 3, the operation of the pallet truck 100 will be described.

Figure 4 shows the fork 130 in a lowered position from the position shown in Figure 1. First, the piston rod 142 of the double-acting cylinder 140 is retracted into the tube 143. Next, a retraction force is generated in the connection part 141 in response to the movement of the piston rod 142, and as the base part 120 descends, the fork 130 descends. Next, the intermediate wheel 133 touches the ground.

Figure 5 shows the fork 130 tilted from the state shown in Figure 4. Following Figure 4, the piston rod 142 is further retracted into the tube 143. Next, a further retraction force is generated in the connection part 141 in response to the movement of the piston rod 142. Next, the fork 130 tilts as the base part 120 tilts, with the intermediate wheel 133 as the fulcrum. The direction in which the fork 130 tilts is the direction in which the front running wheel 131 lifts off the ground.

Figure 6 shows the fork 130 tilted further from the state shown in Figure 5. Following Figure 5, the piston rod 142 is further retracted into the tube 143. The movement of the piston rod 142 then generates a further retraction force on the connection portion 141. Next, the base portion 120 further tilts with the intermediate wheel 133 as a fulcrum, causing the fork 130 to tilt further.

In this way, the tilt angle of the fork 130 changes depending on the amount of action exerted by the double-acting cylinder 140. Here, the amount of action exerted by the double-acting cylinder 140 refers to the pulling force exerted on the connection part 141 according to the amount of movement of the piston rod 142. In this manner, the tilt angle of the fork 130 can be changed depending on the type of pallet 200.

The tilt of the fork 130 can be described as follows (1) and (2): (1) The double-acting cylinder 140 is configured to be able to act on the base 120 when the intermediate wheel 133 is in contact with the ground. (2) Due to the action of the double-acting cylinder 140, the fork 130 tilts with the intermediate wheel 133 as a fulcrum so that the front running wheel 131 rises from the ground surface.

As shown in Figures 4 to 6, the link mechanism 150 operates in response to the action of the double-acting cylinder 140, causing the front traveling wheel 131 to move. Specifically, this is as follows (1) to (3): (1) The first link portion 151 swings clockwise in the figure in response to the lowering of the base portion 120. (2) The second link portion 152 slides toward the arrow 170 in response to the swinging of the first link portion 151. (3) The third link portion 153 swings clockwise in the figure in response to the sliding of the second link portion 152, moving the front traveling wheel 131 inside the fork 130. According to this configuration, the front traveling wheel 131 can be moved inside the fork 130 as the fork 130 tilts.

4. Insertion Operation into Pallet 200 In Section 4, the operation when the forks 130 of the pallet truck 100 are inserted into the pallet 200 will be described.

Figure 7 shows the tilted fork 130 before it is inserted into the pallet 200. The shape of the fork 130 will now be described. In Figure 7, the fork 130 is divided into sections 310, 320, and 330. In section 310, the fork 130 tapers toward the arrow 160 side. In section 320, the fork 130 has a constant thickness. In section 330, the fork 130 is formed so that its thickness decreases toward the arrow 170 side (as it approaches the base 120). In other words, the fork 130 is formed so that its rear end (thickness of section 330) is thinner than its front end (thickness of section 320). This configuration prevents interference between the rear end of the fork 130 and the ground when the fork 130 is tilted.

Figure 8 shows the state in which the tilted fork 130 is inserted halfway into the pallet 200. Figure 9 shows the state in which the tilted fork 130 is inserted all the way into the pallet 200. As shown in Figures 7 to 9, it can be seen that the front running wheels 131 of the fork 130 do not interfere with the bottom board 230 of the pallet 200.

This embodiment prevents impact on the pallet truck 100 when inserting the pallet 200, and also reduces localized load increases when the pallet truck 100 is driven after transporting the pallet 200 (for example, as described in Patent Document 1, an increase in load on the training wheels due to the weight of the entire fork being placed on the training wheels).

The above describes an embodiment of the present invention, but the present invention is not limited to this and can be modified as appropriate without departing from the technical concept of the invention.

5. Modifications In Section 5, modifications of this embodiment will be described.

In this embodiment, the intermediate wheel 133 has been described as being located at the rear end, which is the end connected to the base 120, but this is not limited to this. The intermediate wheel 133 may also be located midway between the front end, which is the end opposite the base 120, and the rear end. The adjustment interval for the tilt angle of the fork 130 can be changed depending on the position of the intermediate wheel 133. The adjustment interval for the tilt angle of the fork 130 can be set depending on each of the elements: the position of the intermediate wheel 133, the amount of movement of the piston rod 142, and the length of the fork 130, so the tilt angle of the fork 130 can be adjusted to suit the specifications of the pallet 200.

In this embodiment, the claimed rear running wheels are described as Mecanum wheels 111, but this is not limited to this. The claimed rear running wheels may be omnidirectional wheels, for example, omniwheels. This embodiment makes it possible to provide a pallet truck 100 that is capable of omnidirectional movement.

The rear running wheels in the claims may also be differentially driven drive wheels. In this case, the front running wheels 131 may be unidirectional casters. This configuration provides a pallet truck 100 that can move forward, backward, and turn left and right. Since unidirectional casters are less likely to wobble while running compared to swivel casters, they can be combined with differentially driven drive wheels to achieve stable running.

The vehicle body 110 may be equipped with a steering mechanism. In this case, the pallet truck 100 can move in all directions.

The intermediate wheel 133 may be configured to automatically adjust its height. In this case, the intermediate wheel 133 may be configured so that the height position of the support shaft is adjusted by an actuator.

In this embodiment, the pallet truck 100 is described as an unmanned vehicle, but it may also be a manned vehicle that is manually operated.

6. Others The present invention may be provided in the following forms.

(1) A transport vehicle comprising a vehicle body, a base unit, a fork, and a lifting unit; the vehicle body has rear running wheels and is configured to move the entire transport vehicle in response to the operation of the rear running wheels; the base unit is supported by the vehicle body; the fork is connected to the base unit and extends horizontally; the lifting unit is connected to the base unit and is configured to raise and lower the base unit and the fork; the fork has front running wheels and intermediate wheels; the front running wheels are located at the front end, which is the end opposite the base unit; and the intermediate wheels are located at the rear end, which is the end connected to the base unit, or at an intermediate portion between the front end and the rear end; the lifting unit is configured to act on the base unit when the intermediate wheels are in contact with the ground; and the fork tilts, due to the action of the lifting unit, with the intermediate wheels as a fulcrum, so that the front running wheels rise above the ground.

This configuration prevents impacts on the transport vehicle when inserting the pallet, and also reduces localized increases in load when the pallet is moved after being transported.

(2) A transport vehicle as described in (1) above, in which the inclination angle of the forks changes depending on the amount of action by the lifting unit.

This configuration allows the fork's inclination angle to be changed depending on the type of pallet.

(3) A transport vehicle as described in (1) or (2) above, wherein the fork is formed so that the thickness of the rear end is less than the thickness of the front end.

This configuration prevents interference between the rear end of the fork and the ground when the fork is tilted.

(4) A transport vehicle according to any one of (1) to (3) above, wherein the intermediate wheels are screw-in casters.

This configuration can prevent interference between the rear end of the fork and the ground when the fork is tilted, depending on the type of pallet.

(5) A transport vehicle according to any one of (1) to (4) above, further comprising a link mechanism, the link mechanism being interposed between the base and the front traveling wheels, and configured to move the front traveling wheels into the interior of the forks when the forks are tilted.

This configuration prevents interference between the front wheels and the board on the road side of the pallet.

(6) A transport vehicle according to (5) above, wherein the link mechanism includes a first link portion, a second link portion, and a third link portion, the first link portion being swingably supported on the base portion, the second link portion being connected to the first link portion and configured to be slidable in a direction approximately parallel to the forks, the third link portion being connected to the second link portion and swingably supported on the front ends of the forks, the front wheels being connected to the third link portion, the first link portion swinging in response to the lowering of the base portion, the second link portion sliding in response to the swinging of the first link portion, and the third link portion swinging in response to the sliding of the second link portion, thereby moving the front wheels into the interior of the forks.

In this manner, the front wheel can be moved inside the fork as the fork tilts.

(7) A transport vehicle according to any one of (1) to (6) above, wherein the rear wheels for running are omnidirectional wheels and the front wheels for running are swivel casters.

This aspect makes it possible to provide a transport vehicle that can move in all directions.

(8) A transport vehicle as described in (7) above, wherein the front wheels for running are dual-wheel swivel casters.

This configuration allows the transport vehicle to turn smoothly.

(9) A transport vehicle according to any one of (1) to (6) above, wherein the rear wheels are drive wheels capable of differential driving, and the front wheels are one-way casters.

According to this aspect, it is possible to provide a transport vehicle that can move forward, backward, and turn left and right.
Of course, this is not the case.

100: Pallet truck 110: Vehicle body 111: Mecanum wheel 120: Base 130: Fork 131: Front running wheel 132: Caster base 133: Intermediate wheel 140: Double-acting cylinder 141: Connection part 142: Piston rod 143: Tube 150: Link mechanism 151: First link part 152: Second link part 153: Third link part 154: Connection part 155: Swing fulcrum 156: Connection part 157: Swing fulcrum 158: Connection part 159: Connection part 160: Arrow 170: Arrow 200: Pallet 210: Beam 220: Flat board 230: Bottom board 240: Insertion port 310: Section 320: Section 330: Section

Claims (8)

A transport vehicle,
The vehicle includes a vehicle body, a base, a fork, and a double-acting cylinder .
the vehicle body has rear wheels for running, and is configured to move the entire transport vehicle in response to operation of the rear wheels for running;
the base portion includes a lower portion supported by the vehicle body and formed in a rectangular parallelepiped shape, and an upper portion extending from an upper surface of the lower portion to an opposite side to the fork,
The fork is connected to the base and extends horizontally,
the double-acting cylinder is connected to the base and configured to raise and lower the base and the forks;
The fork has a front wheel and an intermediate wheel for running,
the front wheel for running is disposed at a front end portion, which is an end portion opposite to the base portion,
the intermediate wheel is disposed at a rear end portion which is an end portion connected to the base portion, or at an intermediate portion between the front end portion and the rear end portion,
the double-acting cylinder is configured to be able to act on the base portion when the intermediate wheel is in contact with the ground,
the action is a force applied to a tip of the upper portion of the base portion,
The fork is tilted by the action of the double-acting cylinder , with the intermediate wheel as a fulcrum, so that the front running wheel rises above the ground surface,
The tilt angle of the fork varies depending on the amount of action by the double-acting cylinder.
Transport vehicle. The transport vehicle according to claim 1,
The fork is formed so that the thickness of the rear end is smaller than the thickness of the front end.
Transport vehicle. The transport vehicle according to claim 1,
The intermediate wheel is a screw-in caster.
Transport vehicle. The transport vehicle according to claim 1,
Furthermore, a link mechanism is provided,
the link mechanism is interposed between the base portion and the front running wheel,
The link mechanism is configured to move the front traveling wheel into the fork when the fork is tilted.
Transport vehicle. The transport vehicle according to claim 4 ,
the link mechanism includes a first link portion, a second link portion, and a third link portion,
the first link portion is swingably supported by the base portion,
the second link portion is connected to the first link portion and configured to be slidable in a direction substantially parallel to the fork,
the third link portion is connected to the second link portion and is swingably supported on the front end portion of the fork,
the front traveling wheel is connected to the third link portion,
the first link portion swings in response to the lowering of the base portion,
the second link portion slides in response to the swing of the first link portion,
The third link portion swings in response to the sliding of the second link portion, and moves the front traveling wheel into the inside of the fork.
Transport vehicle. The transport vehicle according to claim 1,
the rear wheels for driving are omnidirectional wheels,
The front wheels for running are swivel casters.
Transport vehicle. The transport vehicle according to claim 6 ,
The front wheels for running are double-wheel swivel casters.
Transport vehicle. The transport vehicle according to claim 1,
the rear wheels for running are drive wheels capable of differential driving,
The front wheels for running are one-way casters.
Transport vehicle.