Conveying vehicle

Abstract

To provide a conveying vehicle that can prevent impact from imparting onto the conveying vehicle during insertion into a pallet and can suppress an increase in a local load when caused to travel after conveying the pallet.SOLUTION: A conveying vehicle 100 is provided with a vehicle main body 110, a base part 120, a pair of forks 130 and a lifting part 140. The pair of forks is formed to be connected to the base part 120 and to extend in a horizontal direction. The fork 130 has front wheels 131 for travelling and an intermediate wheel 133. The intermediate wheel 133 is arranged at a rear end part which is an end part connected to the base part 120 or at an intermediate part between a front end part and the rear end part. The lifting part 140 is configured to be able to act on the base part 120, in a state where the intermediate wheel 133 is grounded. The fork 130 inclines so that the front wheels 131 for travelling float from a ground contact surface with the intermediate wheel 133 as a fulcrum, by the action by the lifting part 140.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a transport vehicle.

Background Art

[0002] Patent Document 1 discloses a low-lift truck.

[0003] This low-lift truck will be described. A drive unit equipped with a single-acting cylinder device, a base unit connected via a lift arm, a fork extending forward and inserted into a pallet for loading goods, and a load wheel that is attached to the tip of the fork so as to be able to rise and fall and is connected via the lift arm and a push rod, and rises and falls to raise and lower the fork by the rotation of the lift arm accompanying the raising and lowering of the cylinder device. An auxiliary wheel that touches the ground during the descent of the base unit is provided near the base end of the fork at the lower end of the base unit. After touching the ground, the push rod is pulled toward the lift arm side to store the load wheel inside the fork. As a biasing means, a coil spring is provided between the fork and the push rod.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the low-lift truck disclosed in Patent Document 1, the load wheels arranged at the front end of the forks are automatically stored inside the forks when the forks are lowered. Therefore, in this lift truck, when inserting the forks into the pallet, the load wheels do not interfere with the board on the road surface side of the pallet, so the impact on the lift truck during insertion into the pallet is prevented. However, in this lift truck, when driving after transporting the pallet, since the entire weight of the forks is applied to the auxiliary wheels, there is a risk of increasing the failure rate of the parts around the auxiliary wheels.

[0006] In view of the above circumstances, the present invention aims to provide a transport vehicle or the like that can prevent impact on the transport vehicle when inserting into a pallet and can reduce local load increase when driving after transporting the pallet.

Means for Solving the Problems

[0007] According to one aspect of the present invention, a transport vehicle is provided. This transport vehicle includes a vehicle body, a base portion, forks, and a lifting portion. The vehicle body has rear wheels for traveling and is configured to move the entire transport vehicle in accordance with the operation of the rear wheels for traveling. The base portion is supported by the vehicle body. The forks are connected to the base portion and are formed to extend in the horizontal direction. The lifting portion is connected to the base portion and is configured to raise and lower the base portion and the forks. The forks have front wheels for traveling and intermediate wheels. The front wheels for traveling are arranged at the front end, which is the end opposite to the base portion. The intermediate wheels are arranged at the rear end, which is the end on the side connected to the base portion, or at an intermediate portion between the front end and the rear end. The lifting portion is configured to be able to act on the base portion in a state where the intermediate wheels are in contact with the ground. The forks are inclined by the action of the lifting portion so that the front wheels for traveling float from the ground surface with the intermediate wheels as the fulcrum.

[0008] According to such an aspect, it is possible to reduce the impact on the transport vehicle when inserting into the pallet and to reduce the local load increase when driving after transporting the pallet.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Various characteristic matters shown in the following embodiments can be combined with each other.

[0011] 1. Configuration of the pallet truck 100 In the first section, the configuration of the pallet truck 100 used in the present embodiment will be described.

[0012] 1-1. Pallet truck 100 FIG. 1 is a diagram showing the configuration of the pallet truck 100. The pallet truck 100 is an example of the "transport vehicle" in the claims. The pallet truck 100 includes a vehicle body 110, a base portion 120, forks 130, a double-acting cylinder 140 (an example of the "lifting portion" in the claims), and a link mechanism 150. These components will be further described. Here, it is assumed that the pallet truck 100 is an autonomous vehicle that receives a control signal via a communication unit (not shown) and operates based on the control signal.

[0013] 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 the "rear wheels for traveling" in the claims) and is configured to move the entire pallet truck 100 in response to the operation of the mecanum wheels 111. A control device for controlling the double-acting cylinder 140 and the mecanum wheels 111, a battery, etc. are stored in the vehicle body 110. The vehicle body 110 is formed of steel. The vehicle body 110 is formed in a box shape.

[0014] 1-3. Base Portion 120 The base portion 120 is supported on the vehicle body 110 on the side of the arrow 160. The base portion 120 supports the forks 130, the double-acting cylinder 140, and the first link portion 151 of the link mechanism 150. The base portion 120 is formed of steel. The base portion 120 is composed of a lower portion formed in a rectangular parallelepiped shape and an upper portion extending in the direction of the arrow 170 from the lower portion.

[0015] 1-4. Forks 130 The fork 130 is connected to the lower part of the base portion 120. The fork 130 can lift the pallet 200 by shifting from the lowered state to the raised state while being inserted into the insertion port 240 of the pallet 200. That is, the fork 130 is configured such that the load stacked on the pallet 200 can be placed via the pallet 200. The fork 130 is formed of steel. The fork 130 is formed such that each bifurcated part extends horizontally in the direction of arrow 160 with the lower part of the base portion 120 as a base point. The fork 130 is formed in a hollow shape.

[0016] The fork 130 has front traveling wheels 131 and intermediate wheels 133. These components will be further described.

[0017] The front traveling wheels 131 are arranged at the front end, which is the end on the side opposite to the base portion 120. That is, the front traveling wheels 131 are arranged at the front end, which is the end on the arrow 160 side of the fork 130. The front traveling wheels 131 are double-wheel swivel casters. The front traveling wheels 131 are attached to the caster base 132. Since the swivel caster has superior turning performance compared to a one-way caster, free travel can be realized in combination with all-direction wheels.

[0018] The intermediate wheels 133 are fixedly arranged at the rear end, which is the end on the side connected to the base portion 120. That is, the intermediate wheels 133 are fixedly arranged at the rear end, which is the end on the arrow 170 side of the fork 130. The intermediate wheels 133 are screw-in casters. Since the intermediate wheels 133 are fixed to the fork 130, the relative position with respect to the fork 130 does not change even due to the movement of the fork 130 or the load on the intermediate wheels 133, and the position in the height direction can be displaced by a screwing operation. The screwing operation may be manual or automatic. According to such an aspect, interference between the rear end of the fork 130 and the ground can be prevented when the fork 130 is inclined according to the type of the pallet 200.

[0019] 1-5. Double-acting cylinder 140 The double-acting cylinder 140 is connected to the base portion 120. More specifically, the double-acting cylinder 140 is disposed by being connected to the connection portion 141 of the base portion 120 and the connection portion 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 portion 120 and the fork 130.

[0020] 1-6. Link mechanism 150 The link mechanism 150 is disposed intervening between the base portion 120 and the front traveling wheel 131. The link mechanism 150 is configured to move the front traveling wheel 131 inside the fork 130 when the fork 130 is tilted. According to such an aspect, interference between the front traveling wheel 131 and the bottom board 230 of the pallet 200 can be prevented. The movement of the front traveling wheel 131 will be described later.

[0021] 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 further described.

[0022] The first link portion 151 has an L shape. The first link portion 151 is swingably supported by the vehicle body 110 at the connection portion 154. The first link portion 151 has a swing fulcrum 155 at the bent portion of the L shape. The first link portion 151 is swingably supported by the base portion 120 at the swing fulcrum 155.

[0023] The second link portion 152 has a rod shape. 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 substantially parallel to the fork 130.

[0024] 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 at the swing fulcrum 157 on the front end portion of the fork 130. 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 wheel 131 for traveling is connected to the third link portion 153.

[0025] 2. Configuration of the pallet 200 In the second section, the configuration of the pallet 200 used in the present embodiment will be described.

[0026] FIG. 2 is a plan-side perspective view of the pallet 200. FIG. 3 is a bottom-side perspective view of the pallet 200. The pallet 200 has three ribs 210, a plurality of flat boards 220, a plurality of bottom boards 230, and two insertion ports 240.

[0027] The ribs 210 are arranged on both sides and in the middle of the pallet 200. The ribs 210 form the framework of the pallet 200. The ribs 210 are formed in a rectangular parallelepiped shape.

[0028] The flat boards 220 are arranged on the plane side of the pallet 200 at a predetermined interval in a direction orthogonal to the ribs 210. The plurality of flat boards 220 can be a loading surface for luggage. The flat boards 220 are formed in a plate shape.

[0029] The bottom boards 230 are arranged on the bottom side of the pallet 200 at a predetermined interval in a direction orthogonal to the ribs 210. The plurality of bottom boards 230 form the grounding surface of the pallet 200. The bottom boards 230 are formed in a plate shape.

[0030] The insertion port 240 is a space formed by the digits 210, the flat board 220, and the bottom board 230. The two insertion ports 240 function as the insertion ports for the respective forks 130 of the bifurcated fork.

[0031] 3. Operation of the pallet truck 100 In the third section, the operation of the pallet truck 100 will be described.

[0032] FIG. 4 is a diagram showing a state in which the position of the fork 130 is lowered from the state of FIG. 1. First, the piston rod 142 of the double-acting cylinder 140 is drawn into the tube 143. Subsequently, a drawing force is generated in the connecting portion 141 according to the operation of the piston rod 142, and as the base portion 120 descends, the fork 130 descends. Subsequently, the intermediate wheel 133 comes into contact with the ground.

[0033] FIG. 5 is a diagram showing a state in which the fork 130 is tilted from the state of FIG. 4. Following FIG. 4, the piston rod 142 is further drawn into the tube 143. Subsequently, a further drawing force is generated in the connecting portion 141 according to the operation of the piston rod 142. Subsequently, with the intermediate wheel 133 as a fulcrum, as the base portion 120 tilts, the fork 130 tilts. The tilting direction of the fork 130 is the direction in which the front traveling wheel 131 floats from the ground contact surface.

[0034] FIG. 6 is a diagram showing a state in which the fork 130 is further tilted from the state of FIG. 5. Following FIG. 5, the piston rod 142 is further drawn into the tube 143. Subsequently, a further drawing force is generated in the connecting portion 141 according to the operation of the piston rod 142. Subsequently, with the intermediate wheel 133 as a fulcrum, as the base portion 120 further tilts, the fork 130 further tilts.

[0035] In this way, the inclination angle of the fork 130 changes according to the amount of action by the double-acting cylinder 140. Here, the amount of action by the double-acting cylinder 140 is the pulling force on the connecting portion 141 according to the moving amount of the piston rod 142. According to such an aspect, the inclination angle of the fork 130 can be changed according to the type of the pallet 200.

[0036] In other words, the inclination of the fork 130 is as follows from (1) to (2) below. (1) The double-acting cylinder 140 is configured to be able to act on the base portion 120 in a state where the intermediate wheel 133 is in contact with the ground. (2) The fork 130 is inclined by the action of the double-acting cylinder 140 so that the front traveling wheel 131 floats from the ground surface with the intermediate wheel 133 as a fulcrum.

[0037] As shown in FIGS. 4 to 6, when the link mechanism 150 operates according to the action of the double-acting cylinder 140, the front traveling wheel 131 moves. Specifically, it is as follows from (1) to (3) below. (1) The first link portion 151 swings clockwise in the drawing according to the lowering of the base portion 120. (2) The second link portion 152 slides toward the arrow 170 side according to the swing of the first link portion 151. (3) The third link portion 153 swings clockwise in the drawing according to the slide of the second link portion 152, and moves the front traveling wheel 131 inside the fork 130. According to such an aspect, the front traveling wheel 131 can be moved inside the fork 130 as the fork 130 inclines.

[0038] 4. Insertion operation into the pallet 200 In Section 4, the operation when the fork 130 of the pallet truck 100 is inserted into the pallet 200 will be described.

[0039] FIG. 7 is a diagram showing the state before the inclined fork 130 is inserted into the pallet 200. Here, the shape of the fork 130 will be described. In FIG. 7, the fork 130 is assumed to be divided into a section 310, a section 320, and a section 330. In the section 310, the fork 130 has a tapered shape toward the arrow 160 side. In the section 320, the fork 130 has a constant thickness. In the section 330, the fork 130 is formed such that its thickness decreases toward the arrow 170 side (as it approaches the base portion 120). In other words, the fork 130 is formed such that the thickness of the rear end portion (the thickness of the section 330) is less than the thickness of the front end portion (the thickness of the section 320). According to such an aspect, when the fork 130 is inclined, interference between the rear end portion of the fork 130 and the ground can be prevented.

[0040] FIG. 8 is a diagram showing the state where the inclined fork 130 is inserted halfway into the pallet 200. FIG. 9 is a diagram showing the state where the inclined fork 130 is inserted to the back of the pallet 200. As shown in FIGS. 7 to 9, it can be seen that the traveling front wheel 131 of the fork 130 does not interfere with the bottom board 230 of the pallet 200.

[0041] According to the aspect of the present embodiment, it is possible to prevent an impact on the pallet truck 100 when inserting into the pallet 200, and to reduce a local load increase (for example, as described in Patent Document 1, an increase in the load on the auxiliary wheel due to the weight of the entire fork being applied to the auxiliary wheel) when the pallet truck 100 is run after transporting the pallet 200.

[0042] As described above, the embodiments of the present invention have been described, but the present invention is not limited thereto, and can be appropriately modified without departing from the technical idea of the invention.

[0043] 5. Modification In Section 5, a modification of the present embodiment will be described.

[0044] In this embodiment, the intermediate wheel 133 has been described as being disposed at the rear end, which is the end connected to the base portion 120. However, the present invention is not limited to this. The intermediate wheel 133 may be disposed at an intermediate portion between the front end, which is the end on the side opposite to the base portion 120, and the rear end. Depending on the position of the intermediate wheel 133, the adjustment interval of the inclination angle of the fork 130 can be changed. Since the adjustment interval of the inclination angle of the fork 130 can be set by each element of the position of the intermediate wheel 133, the movement amount of the piston rod 142, and the length of the fork 130, the inclination angle of the fork 130 can be adjusted according to the specifications of the pallet 200.

[0045] In this embodiment, the driving rear wheel of the claim has been described as the mecanum wheel 111. However, the present invention is not limited to this. The driving rear wheel of the claim may be any omnidirectional wheel, for example, an omni wheel. According to such an aspect, a pallet truck 100 capable of omnidirectional movement can be provided.

[0046] Also, the driving rear wheel of the claim may be a driving wheel capable of differential drive. In this case, the driving front wheel 131 may be a one-way caster. According to such an aspect, a pallet truck 100 capable of forward movement, backward movement, and left and right turning movement can be provided. Here, since the one-way caster is less likely to cause play during running compared to a swivel caster, stable running can be realized in combination with a driving wheel capable of differential drive.

[0047] The vehicle body 110 may be provided with a steering mechanism. In this case, the pallet truck 100 can move in all directions.

[0048] The intermediate wheel 133 may be configured to automatically adjust its height. In this case, the intermediate wheel 133 may be configured such that the height position of the support shaft is adjusted by an actuator.

[0049] In this embodiment, the pallet truck 100 has been described as an autonomous vehicle, but it may also be a manned vehicle that travels by manual operation.

[0050] 6. Others It may also be provided in each of the following aspects.

[0051] (1) A transport vehicle, comprising a vehicle body, a base portion, forks, and a lifting portion, wherein the vehicle body has rear wheels for traveling and is configured to move the entire transport vehicle in accordance with the operation of the rear wheels for traveling, the base portion is supported by the vehicle body, the forks are connected to the base portion and are formed to extend in the horizontal direction, the lifting portion is connected to the base portion and is configured to lift and lower the base portion and the forks, the forks have front wheels for traveling and intermediate wheels, the front wheels for traveling are disposed at a front end portion which is an end portion opposite to the base portion, the intermediate wheels are disposed at a rear end portion which is an end portion on the side connected to the base portion, or at an intermediate portion between the front end portion and the rear end portion, the lifting portion is configured to be able to act on the base portion in a state where the intermediate wheels are in contact with the ground, and the forks are inclined so that the front wheels for traveling float from the ground surface with the intermediate wheels as a fulcrum by the action of the lifting portion.

[0052] According to such an aspect, it is possible to prevent an impact on the transport vehicle when inserting the pallet, and it is possible to reduce a local load increase when traveling after pallet transportation.

[0053] (2) The transport vehicle according to (1) above, wherein the inclination angle of the forks changes according to the amount of the action by the lifting portion.

[0054] According to such an aspect, it is possible to change the inclination angle of the forks according to the type of the pallet.

[0055] (3) In the transport vehicle according to the above (1) or (2), the fork is formed such that the thickness of the rear end portion is less than that of the front end portion, the transport vehicle.

[0056] According to such an aspect, when the fork is inclined, interference between the rear end portion of the fork and the ground can be prevented.

[0057] (4) In the transport vehicle according to any one of the above (1) to (3), the intermediate wheel is a screw-in caster, the transport vehicle.

[0058] According to such an aspect, depending on the type of pallet, interference between the rear end portion of the fork and the ground can be prevented when the fork is inclined.

[0059] (5) In the transport vehicle according to any one of the above (1) to (4), further comprising a link mechanism, the link mechanism being interposed between the base portion and the front driving wheel, and the link mechanism being configured to move the front driving wheel inside the fork when the fork is inclined, the transport vehicle.

[0060] According to such an aspect, interference between the front driving wheel and the board on the road surface side of the pallet can be prevented.

[0061] (6) In the transport vehicle according to the above (5), the link mechanism includes a first link portion, a second link portion, and a third link portion, the first link portion being swingably supported by the base portion, the second link portion being connected to the first link portion and configured to be slidable in a direction substantially parallel to the fork, the third link portion being connected to the second link portion and swingably supported by the front end portion of the fork, the front driving wheel being connected to the third link portion, the first link portion swinging in response to a descent of the base portion, the second link portion sliding in response to the swing of the first link portion, the third link portion swinging in response to the slide of the second link portion, and moving the front driving wheel inside the fork, the transport vehicle.

[0062] According to such an aspect, as the fork tilts, the front driving wheel can be moved inside the fork.

[0063] (7) In the transport vehicle according to any one of (1) to (6) above, the rear driving wheel is an omnidirectional wheel, and the front driving wheel is a swivel caster, the transport vehicle.

[0064] According to such an aspect, a transport vehicle capable of omnidirectional movement can be provided.

[0065] (8) In the transport vehicle according to (7) above, the front driving wheel is a double-wheel swivel caster, the transport vehicle.

[0066] According to such an aspect, when turning the transport vehicle, it can be smoothly turned.

[0067] (9) In the transport vehicle according to any one of (1) to (6) above, the rear driving wheel is a drive wheel capable of differential drive, and the front driving wheel is a one-way caster, the transport vehicle.

[0068] According to such an aspect, a transport vehicle capable of forward, backward, and left and right turning movements can be provided. Of course, this is not the limit.

Explanation of Signs

[0069] 100: Pallet truck 110: Vehicle body 111: Mecanum wheel 120: Base part 130: Fork 131: Front driving 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: Oscillation fulcrum 156: Connection part 157: Oscillation fulcrum 158: Connection part 159: Connection part 160: Arrow 170: Arrow 200: Pallet 210: Character 220: Flat board 230: Bottom board 240: Insertion port 310: Interval 320: Interval 330: Interval

Claims

1. A transport vehicle, comprising: a vehicle body, a base portion, forks, and a lifting portion, wherein the vehicle body has rear wheels for traveling and is configured to move the entire transport vehicle in accordance with the operation of the rear wheels for traveling, the base portion is supported by the vehicle body, the forks are connected to the base portion and are formed to extend in the horizontal direction, the lifting portion is connected to the base portion and is configured to lift and lower the base portion and the forks, the forks have front wheels for traveling and intermediate wheels, the front wheels for traveling are disposed at a front end portion which is an end portion opposite to the base portion, the intermediate wheels are disposed at a rear end portion which is an end portion on the side connected to the base portion, or at an intermediate portion between the front end portion and the rear end portion, the lifting portion is configured to be able to act on the base portion in a state where the intermediate wheels are in contact with the ground, the forks are inclined such that the front wheels for traveling float from the ground surface with the intermediate wheels as a fulcrum by the action of the lifting portion, a transport vehicle.

2. The transport vehicle according to claim 1, wherein the inclination angle of the forks changes according to the amount of the action by the lifting portion, a transport vehicle.

3. The transport vehicle according to claim 1, wherein the forks are formed such that the thickness of the rear end portion is less than the thickness of the front end portion, a transport vehicle.

4. The transport vehicle according to claim 1, wherein the intermediate wheels are screw-in casters, a transport vehicle.

5. The transport vehicle according to claim 1, further comprising: a link mechanism, wherein the link mechanism is interposed between the base portion and the front wheels for traveling, and the link mechanism is configured to move the front wheels for traveling inside the forks when the forks are inclined, a transport vehicle.

6. The transport vehicle according to claim 5, wherein 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 is configured to be slidable in a direction substantially parallel to the forks, [[ID= ​ ​ ​ The third link part swings according to the slide of the second link part, and moves the front traveling wheel into the inside of the fork. Transport vehicle.

7. In the transport vehicle according to claim 1, The rear traveling wheel is an all-directional wheel, The front traveling wheel is a swivel caster. Transport vehicle.

8. In the transport vehicle according to claim 7, The front traveling wheel is a double-wheel swivel caster. Transport vehicle.

9. In the transport vehicle according to claim 1, The rear traveling wheel is a drive wheel capable of differential drive, The front traveling wheel is a one-way caster. Transport vehicle.

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