Transport 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 according to one embodiment of the present invention is provided with a vehicle main body 110, a base part 120, a pair of forks 130 and a lifting part. The vehicle main body has rear wheels 111 for travelling and is configured to move the whole of the conveying vehicle in accordance with movement of the rear wheels for travelling. The base part is supported on the vehicle main body. The pair of forks is formed to be connected to the base part and to extend in a horizontal direction. The lifting part is connected to the base part, and configured to lift the base part and the pair of forks. The fork has front wheels 131 for travelling and an intermediate wheel 133. The fork inclines so that the front wheels for travelling float from a ground contact surface with the intermediate wheel as a fulcrum, by the action performed by the lifting part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a low lift.

[0003] This low-lift truck will now be described. 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 liftable manner and connected to the lift arm via a push rod. The load wheels are raised and lowered by the rotation of the lift arm as the cylinder device moves up and down. 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 the base touches 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. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 08-113145 Summary of the Invention [Problem to be solved by the invention]

[0005] 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 moved 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.

[0006] In consideration of the above circumstances, the present invention provides a transport vehicle etc. that can prevent impact to the transport vehicle when inserting it into a pallet and can reduce localized load increases when the vehicle is driven after transporting the pallet. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided 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 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. 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 and rear ends. The lifting unit is configured to be able to act on the base unit when the intermediate wheels are in contact with the ground. The fork is tilted by the action of the lifting unit, with the intermediate wheels as a fulcrum, so that the front running wheels lift off the ground.

[0008] According to this aspect, it is possible to reduce the impact on the transport vehicle when the pallet is inserted, and also to reduce the increase in local load when the pallet is moved after being transported. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram showing the configuration of a pallet truck 100. FIG. [Figure 2] FIG. 2 is a top perspective view of a pallet 200. [Figure 3] FIG. 2 is a perspective view of the bottom side of the pallet 200. [Figure 4] 2 is a diagram showing a state in which the position of the fork 130 is lowered from the state in FIG. 1. FIG. [Figure 5] 5 is a diagram showing a state in which the fork 130 is tilted from the state shown in FIG. 4. FIG. [Figure 6] 6 is a diagram showing a state in which the fork 130 is further tilted from the state in FIG. 5. FIG. [Figure 7] 10 is a diagram showing the state before the inclined fork 130 is inserted into the pallet 200. FIG. [Figure 8] 10 is a diagram showing a state in which the inclined fork 130 is inserted halfway into the pallet 200. FIG. [Figure 9] 10 is a diagram showing a state in which the inclined fork 130 is inserted deep into the pallet 200. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. Various features shown in the following embodiments can be combined with each other.

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

[0012] 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 comprises 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 below. 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.

[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 running" 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.

[0014] 1-3. Base part 120 The base part 120 is supported on the side of the arrow 160 on the vehicle body 110. 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.

[0015] 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 arrow 160, with the lower part of the base 120 as the base point. The forks 130 are formed hollow.

[0016] The fork 130 has a front wheel 131 for running and an intermediate wheel 133. These components will be further described below.

[0017] The front running wheels 131 are arranged at the front end, which is the end opposite the base part 120. In other words, the front running wheels 131 are arranged at the front end, which is the end of the fork 130 on the side of the arrow 160. The front running wheels 131 are dual-wheel swivel casters. The front running wheels 131 are attached to caster bases 132. Swivel casters have better turning performance than unidirectional casters, and therefore can achieve free running when combined with omnidirectional wheels.

[0018] 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 arrow 170 side. The intermediate wheel 133 is a screw-in caster. Because the intermediate wheel 133 is fixed to the fork 130, its relative position with respect 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 a screw-in operation. The screw-in operation may be manual or automatic. According to this embodiment, interference between the rear end of the fork 130 and the ground can be prevented when the fork 130 is tilted, depending on the type of pallet 200.

[0019] 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.

[0020] 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 tilt. 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.

[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 below.

[0022] The first link portion 151 is L-shaped. The first link portion 151 is swingably supported by the vehicle main body 110 at a connection portion 154. The first link portion 151 has a swing fulcrum 155 at a 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 a 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 on the front end portion 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.

[0025] 2. Palette 200 Configuration In Section 2, the configuration of the pallet 200 used in this embodiment will be described.

[0026] Fig. 2 is a perspective view of the top side of the pallet 200. Fig. 3 is a perspective view of the bottom side of the pallet 200. The pallet 200 has three girders 210, a plurality of flat boards 220, a plurality of bottom boards 230, and two insertion slots 240.

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

[0028] 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. The flat boards 220 can serve as surfaces on which cargo is placed. 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 predetermined intervals in a direction perpendicular to the girders 210. The plurality of bottom boards 230 form the ground contact surface of the pallet 200. The bottom boards 230 are formed in the shape of a plate.

[0030] The insertion slot 240 is a space formed by the spar 210, the flat board 220, and the bottom board 230. The two insertion slots 240 function as insertion slots for the two-pronged forks 130, respectively.

[0031] 3. Operation of Pallet Truck 100 Section 3 describes the operation of the pallet truck 100.

[0032] 4 is a diagram showing a state in which the position of the fork 130 has been lowered from the state in FIG. 1. First, the piston rod 142 of the double-acting cylinder 140 is retracted into the tube 143. Next, a retracting 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.

[0033] Fig. 5 is a diagram showing a state in which the fork 130 is tilted from the state shown in Fig. 4. Following Fig. 4, the piston rod 142 is further retracted into the tube 143. Next, a further retracting 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 a fulcrum. The tilting direction of the fork 130 is the direction in which the front running wheel 131 rises from the ground surface.

[0034] Fig. 6 is a diagram showing a state in which the fork 130 is further tilted from the state in Fig. 5. Following Fig. 5, the piston rod 142 is further retracted into the tube 143. Next, a further retracting force is generated in the connection part 141 in response to the movement of the piston rod 142. Next, the base part 120 further tilts with the intermediate wheel 133 as a fulcrum, and the fork 130 further tilts.

[0035] In this way, the tilt angle of the fork 130 changes depending on the amount of action by the double-acting cylinder 140. Here, the amount of action by the double-acting cylinder 140 refers to the pulling force on the connection part 141 that corresponds to the amount of movement of the piston rod 142. According to this embodiment, the tilt angle of the fork 130 can be changed depending on the type of pallet 200.

[0036] The tilt of the fork 130 can be expressed in other words as follows (1) and (2): (1) The double-acting cylinder 140 is configured to be able to act on the base part 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.

[0037] As shown in FIGS. 4 to 6 , the link mechanism 150 operates in response to the action of the double-acting cylinder 140, thereby moving the front traveling wheel 131. Specifically, this occurs 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 embodiment, the front traveling wheel 131 can be moved inside the fork 130 as the fork 130 tilts.

[0038] 4. Inserting 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.

[0039] FIG. 7 is a diagram showing the state before the tilted fork 130 is inserted into the pallet 200. The shape of the fork 130 will now be described. In FIG. 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.

[0040] Figure 8 is a diagram showing a state in which the inclined fork 130 is inserted halfway into the pallet 200. Figure 9 is a diagram showing a state in which the inclined 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.

[0041] According to the aspects of this embodiment, it is possible to prevent impact on the pallet truck 100 when inserting the pallet 200, and it is also possible to reduce 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).

[0042] Although the embodiment of the present invention has been described above, the present invention is not limited to this and can be modified as appropriate within the scope of the technical idea of ​​the invention.

[0043] 5. Variations In Section 5, a modification of this embodiment will be described.

[0044] In the present embodiment, the intermediate wheel 133 has been described as being disposed at the rear end, which is the end connected to the base 120, but this is not limited thereto. The intermediate wheel 133 may also be disposed in the middle 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 by each of the elements, such as 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.

[0045] In this embodiment, the claimed rear running wheels are described as Mecanum wheels 111, but this is not limiting. The claimed rear running wheels may be omni-directional wheels, for example, omni-wheels. According to this embodiment, a pallet truck 100 capable of omnidirectional movement can be provided.

[0046] Furthermore, the rear running wheels in the claims may be differentially driven drive wheels. In this case, the front running wheels 131 may be unidirectional casters. According to this embodiment, a pallet truck 100 can be provided that can move forward, backward, and turn left and right. Here, unidirectional casters are less likely to wobble while running compared to swivel casters, and therefore can achieve stable running when combined with differentially driven drive wheels.

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

[0048] The intermediate wheel 133 may be configured to automatically adjust the 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.

[0049] In this embodiment, the pallet truck 100 has been described as an unmanned vehicle, but it may also be a manned vehicle that is manually operated to travel.

[0050] 6.Other It may be provided in the following manner.

[0051] (1) A transport vehicle comprising a vehicle body, a base unit, a fork, and a lifting unit, wherein the vehicle body has rear running wheels and is configured to move the entire transport vehicle in accordance with 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 is formed to extend 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 arranged at the front end which is the end opposite to the base unit, and the intermediate wheels are arranged at the rear end which is the end connected to the base unit or at an intermediate part between the front end and the rear end, the lifting unit is configured to be able to act on the base unit when the intermediate wheels are in contact with the ground, and the fork tilts with the intermediate wheels as a fulcrum due to the action of the lifting unit so that the front running wheels rise above the ground surface.

[0052] According to this aspect, it is possible to prevent impact on the transport vehicle when the pallet is inserted, and to reduce localized increases in load when the pallet is moved after being transported.

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

[0054] According to this aspect, the inclination angle of the forks can be changed depending on the type of pallet.

[0055] (3) The transport vehicle according to (1) or (2) above, wherein the fork is formed so that the thickness of the rear end is smaller than the thickness of the front end.

[0056] According to this aspect, when the forks are tilted, interference between the rear ends of the forks and the ground can be prevented.

[0057] (4) A transport vehicle according to any one of (1) to (3) above, wherein the intermediate wheels are screw-in casters.

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

[0059] (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 running wheels, and the link mechanism being configured to move the front running wheels into the interior of the forks when the forks are tilted.

[0060] According to this aspect, interference between the front wheels for running and the board on the road surface side of the pallet can be prevented.

[0061] (6) In the transport vehicle described in (5) above, the link mechanism includes a first link portion, a second link portion, and a third link portion, the first link portion is swingably supported on the base portion, the second link portion is connected to the first link portion and is configured to be slidable in a direction approximately parallel to the fork, the third link portion is connected to the second link portion and swingably supported on the front end portion of the fork, the front running 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 swinging of the first link portion, and the third link portion swings in response to the sliding of the second link portion, moving the front running wheel into the inside of the fork.

[0062] According to this aspect, the front wheel for traveling can be moved inside the fork as the fork is tilted.

[0063] (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.

[0064] According to this aspect, it is possible to provide a transport vehicle that is capable of moving in all directions.

[0065] (8) The transport vehicle according to (7) above, wherein the front wheels for running are double-wheel swivel casters.

[0066] According to this aspect, the transport vehicle can be turned smoothly.

[0067] (9) A transport vehicle according to any one of (1) to (6) above, wherein the rear wheels for running are drive wheels capable of differential driving, and the front wheels for running are one-way casters.

[0068] 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. [Explanation of symbols]

[0069] 100: Pallet truck 110: Vehicle body 111: Mecanum Wheel 120: Base 130: Fork 131: Front wheel for driving 132: Caster stand 133: Intermediate wheel 140: Double-acting cylinder 141: Connection part 142: Piston rod 143: Tube 150: Link mechanism 151: First link 152: Second link 153: Third link 154: Connection part 155: Swing fulcrum 156: Connection part 157: Swing fulcrum 158: Connection 159: Connection 160: Arrow 170: Arrow 200: Palette 210: Digit 220: Flat board 230: Bottom board 240: Outlet 310: Section 320: Section 330: Section

Claims

1. 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 that is an end portion opposite to the base portion, the intermediate wheel is disposed at a rear end portion that 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.

2. 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.

3. The transport vehicle according to claim 1, The intermediate wheel is a screw-in caster. Transport vehicle.

4. 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.

5. In 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.

6. 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.

7. In the transport vehicle according to claim 6, The front wheels for running are double-wheel swivel casters. Transport vehicle.

8. 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.

Images