Load platform lifting device

Abstract

To secure a working space of a conveying machine while properly functioning a caster stopper.SOLUTION: A load-bearing platform lifting and lowering device that lifts and lowers a load-bearing platform with respect to a vehicle, the load-bearing platform lifting and lowering device including a caster stopper provided on the load-bearing platform, wherein the caster stopper includes a first caster stopper and a second caster stopper that are located on left and right sides, respectively, in a rear portion of the load-bearing platform, and the first caster stopper and the second caster stopper are disposed at an interval in a left-right direction such that a load-bearing surface is interposed therebetween.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a loading platform lifting device. [Background technology]

[0002] The loading platform lifting device is a device that raises and lowers the loading platform between the height of the floor surface of the vehicle's loading platform and the ground, and supports loading and unloading of cargo onto the loading platform. To reduce the labor and manpower required for loading and unloading, the use of transport machines such as AGVs (Automatic Guided Vehicles) is being considered for loading and unloading operations using the loading platform lifting device (Patent Document 1, etc.). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2022-044082 Summary of the Invention [Problem to be solved by the invention]

[0004] The work of loading cargo onto a vehicle using a loading platform lifting device is generally carried out as follows. For example, when working alone, the worker first places the cargo on a loading platform on the ground, raises the loading platform partway and stops it, and then uses the loading platform as a foothold to climb onto the platform. The worker then raises the loading platform to the height of the platform and carries the cargo on the loading platform onto the platform. When working with multiple people, one worker is stationed on the ground and the other on the platform. The ground worker first places the cargo on the loading platform, and when the ground worker leaves the platform, the worker on the platform raises the loading platform to the height of the platform and carries the cargo on the platform onto the platform.

[0005] When working alone, the same worker must load the cargo onto the receiving platform on the ground, and then lift the platform and carry the cargo from the receiving platform onto the loading platform, which is both cumbersome and labor-intensive. When working with multiple people, the work is shared between the ground worker and the worker on the loading platform, reducing the labor required, but increasing the waiting time for each worker. One effective solution to these issues is to use a transport machine such as an AGV, as described in Patent Document 1.

[0006] However, in cargo handling work using a platform lifting device, since the cargo to be loaded and unloaded from the platform and the work environment vary, there are many situations in which work can be performed more flexibly and efficiently by, for example, dividing the ground work and the work on the platform between an operator and an automated guided vehicle, with a human taking the lead in the work while using the automated guided vehicle as an auxiliary, rather than having the automated guided vehicle perform both the ground work and the work on the platform as in Patent Document 1. For example, when the work of loading cargo onto the platform of a vehicle is divided between an operator and a transport machine, it is assumed that the ground transport machine will carry the cargo onto the platform of the platform lifting device, and after the transport machine moves away from the platform, the operator on the platform will raise the platform and carry the cargo from the platform onto the platform.

[0007] When a load loaded on a trolley is raised or lowered by a platform lifting device, a caster stopper attached to the platform is used to prevent the load from falling off during lifting. These caster stoppers are generally configured to stand upright in a tilted position toward the platform due to spring force when unlocked. When a transport vehicle approaches the platform from the ground (i.e., from the opposite side of the platform), the caster stopper is stepped on and knocked over by the transport vehicle. However, if the transport vehicle climbs over the caster stopper, it may get caught on the raised caster stopper and be unable to descend from the platform. Furthermore, if the transport vehicle lowers a load onto the platform without climbing over the caster stopper completely and holding down the caster stopper, the transport vehicle may be able to descend from the platform. However, if the transport vehicle lowers a load onto the platform while holding down the caster stopper, the load may climb up onto the caster stopper, causing the caster stopper to malfunction. In the technology of Patent Document 1, the conveying machine moves up and down on the loading platform, and the load is held by the conveying machine during this time, so the above-mentioned problem with the caster stoppers does not occur.

[0008] An object of the present invention is to provide a loading platform lifting device that can ensure working space for a conveying machine while allowing a caster stopper to function properly. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the present invention provides a loading platform lifting device for raising and lowering a loading platform relative to a vehicle, the loading platform being equipped with caster stoppers provided on the loading platform, the caster stoppers including a first caster stopper and a second caster stopper located on the left and right sides respectively at the rear of the loading platform, the first caster stopper and the second caster stopper being arranged at a distance from each other on the left and right so that a loading surface is interposed between them. [Effects of the Invention]

[0010] According to the present invention, it is possible to ensure a working space for the conveying machine while allowing the caster stopper to function properly. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a side view showing the overall structure of a vehicle equipped with a loading platform lifting device according to a first embodiment of the present invention. [Figure 2] 1 is an enlarged side view of a loading platform lifting and lowering device according to a first embodiment of the present invention. [Figure 3] 1 is a plan view of a receiving platform provided in a receiving platform lifting device according to a first embodiment of the present invention. [Figure 4] FIG. 4 is an enlarged view of a portion VI in FIG. [Figure 5] 5 is a cross-sectional view taken along line VV in FIG. 4. [Figure 6] 1 is a diagram illustrating a switching mechanism provided in a receiving platform lifting and lowering device according to a first embodiment of the present invention. [Figure 7] 1 is a schematic diagram showing an example of work allocation in which a transport machine loads cargo from the ground onto a cargo receiving platform, and a worker carries the cargo from the cargo receiving platform to the loading platform. [Figure 8] FIG. 10 is a schematic diagram illustrating an example of work allocation in which a worker loads luggage from a loading platform onto a luggage receiving platform, and a conveying machine carries the luggage from the luggage receiving platform to the ground. [Figure 9] 3 is an explanatory diagram of a loading and unloading operation of a carriage by a conveying machine onto a loading platform provided in a loading platform lifting and lowering device according to the first embodiment of the present invention. FIG. [Figure 10] 10 is an explanatory diagram of a loading and unloading operation of a carriage by a conveying machine onto a loading platform provided in a loading platform lifting and lowering device according to a second embodiment of the present invention. FIG. [Figure 11] FIG. 10 is a plan view of a loading platform provided in a loading platform lifting device according to a modified example of the first embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] First Embodiment -vehicle- FIG. 1 is a side view showing the overall structure of a vehicle equipped with a platform lifting device according to a first embodiment of the present invention. In this specification, the left and right sides of FIG. 1 refer to the front and rear of the platform lifting device 4. In this specification, the left and right sides of FIG. 1 refer to the front and rear of the platform lifting device. For example, FIG. 1 illustrates a case in which the platform lifting device is mounted on the rear of the vehicle and the platform (platform) 5 is pulled out to the rear of the vehicle, and in this state the front and rear direction of the platform lifting device coincides with the front and rear direction of the vehicle. However, there are also cases in which the platform lifting device 4 is mounted on the side of the vehicle so that the platform 5 is pulled out. In that case, the front and rear direction of the platform lifting device 4 is perpendicular to the front and rear direction of the vehicle.

[0014] The vehicle shown in Fig. 1 is configured to include a chassis frame 1, a driver's cab 2 provided at the front of the chassis 1, a loading platform (load) 3 mounted on the chassis 1, and an underfloor-storable loading platform lifting device 4 provided on the underside of the rear of the chassis 1. When the loading platform lifting device 4 is not in use, such as when the vehicle is traveling, the loading platform 5 is folded and stored under the chassis 1. When in use, the loading platform lifting device 4 unfolds the loading platform 5 by pulling it out rearward, and raises and lowers the loading platform 5 between the height of the floor of the loading platform 3 and the height at which it touches the ground relative to the vehicle, thereby assisting in loading and unloading of cargo onto the loading platform 3.

[0015] -Load receiving platform lifting device- FIG. 2 is an enlarged side view of the receiving platform lifting device. FIG. 2 shows the receiving platform in an unfolded state. The receiving platform lifting device 4 includes a receiving platform 5, a slide unit 10, a lift unit 20, an opening / closing unit (not shown), a power unit 30 (FIG. 4), and a control device 40 (FIG. 4). The slide unit 10 is a unit including an actuator that moves the receiving platform 5 and other components in the forward and backward directions. The lift unit 20 is a unit including an actuator that raises and lowers the receiving platform 5. The opening / closing unit is a unit including an actuator that opens and closes (unfolds / folds) the receiving platform 5. In the receiving platform lifting device 4, the receiving platform 5 may be configured to be opened and closed manually, in which case the opening / closing unit is omitted. The power unit 30 is a drive device that drives the slide unit 10, lift unit 20, and opening / closing unit. The control device 40 is a device that controls the power unit 30. These components will be explained in order.

[0016] -Slide unit- The slide unit 10 includes left and right guide rails 11, a slider 12, and a slide cylinder 13. The left and right guide rails 11 are attached to the rear lower side of the vehicle frame 1 in an orientation extending parallel to the front and rear. The slider 12 is slidably attached to the left and right guide rails 11 and is movable back and forth along the guide rails 11. The slide cylinder 13 is a double-acting hydraulic cylinder, and both ends are fixed to the guide rails 11 and the slider 12 via support members. The extension and contraction of the slide cylinder 13 moves the slider 12 back and forth along the guide rails 11, and the load receiving platform 5 supported by the slider 12 via the lift unit 20 moves back and forth.

[0017] -Lift unit- The lift unit 20 includes a left and right pair of a first arm (tilt arm) 21, a second arm (lift arm) 22, a third arm (compression arm) 23, and a lift cylinder 24. The lift unit 20 supports the portion of the load receiving platform 5 between its left and right ends so as not to interfere with the load receiving surface (the upper surface of the load receiving platform 5). The upper portion of the first arm 21 is connected to the slider 12 via a pin, and the lower portion rotates back and forth. The front end of the second arm 22 is rotatably connected to the first arm 21 and its rear end to the load receiving platform 5 via shafts A and B extending left and right, respectively. The front end of the third arm 23 is rotatably connected to the slider 12 and its rear end to the load receiving platform 5 via shafts C and D extending left and right, respectively. The lift cylinder 24 is a single-acting hydraulic cylinder (a double-acting type is also acceptable), and in this embodiment, the rod side is rotatably connected to the lower part of the first arm 21, and the bottom side is rotatably connected to the second arm 22. The second arm 22 and the third arm 23 form a parallel link that connects the loading platform 5 to the slider 12 so that it can be raised and lowered (the axis AD forms the apex angle of a parallelogram). As the lift cylinder 24 expands and contracts, this parallel link rotates up and down, and the loading platform 5 rises and falls while maintaining a horizontal position.

[0018] -Loading platform- The receiving platform 5 is a platform that receives and raises and lowers luggage and the like, and is foldable in this embodiment. Specifically, the receiving platform 5 includes a base receiving platform 6 connected to the lift unit 20, and a front receiving platform 7 rotatably connected to the rear of the base receiving platform 6 via a hinge (not shown). The front receiving platform 7 rotates about the hinge as a fulcrum, and rotates 180 degrees counterclockwise (left) forward from the unfolded state (FIG. 2) as viewed from the left, and is then folded over and placed on top of the base receiving platform 6 (FIG. 1). The rear end surface of the receiving platform 5 in the folded state forms a bumper (FIG. 1). The left-right width of the receiving platform 5 is, for example, approximately the same as the width of the loading platform 3, and is wider than the outer dimensions of the left and right vehicle frames 1. In this embodiment, the front receiving platform 7 is non-foldable. That is, the receiving platform 5 has a two-piece folding structure that includes only one front receiving platform 7, but it may also have a three-piece folding structure in which the front receiving platform 7 has a two-piece folding structure. Also, when viewed from the left and right, the receiving platform 5 is formed in a triangular shape that becomes thinner from the base end to the tip (rear) when unfolded (as shown in Figure 2).

[0019] Fig. 3 is a plan view of the receiving platform 5, Fig. 4 is an enlarged view of part VI in Fig. 3, Fig. 5 is a cross-sectional view taken along line VV in Fig. 4, and Fig. 6 is a diagram showing the switching mechanism, which will be described later. Note that in Fig. 3, the boundary between the base end receiving platform 6 and the tip end receiving platform 7 has been omitted, and the receiving platform 5 is shown as a single unit.

[0020] The receiving platform 5 is made of extruded aluminum and has multiple hollows 5a (Fig. 5) extending in the width direction to reduce weight. Side moldings 9 are provided on the sides of the receiving platform 5. The side moldings 9 are rod-shaped members with a U-shaped cross section that cover the left and right end faces of the receiving platform 5 and are attached to the receiving platform 5 so as to block the left and right openings of each hollow 5a. The side moldings 9 form a step with respect to the receiving surface of the receiving platform 5 and also function as a stopper for carts placed on the receiving platform 5. Although not shown, side guards that protrude higher from the receiving surface than the side moldings 9 may be installed inside the side moldings 9 (inside in the width direction). When a cart or the like gets on or off the receiving platform 5, the cart passes between the left and right side moldings 9 (or between the left and right side guards, if side guards are provided).

[0021] - Caster stopper - The receiving platform 5 is also provided with caster stoppers 50 that function as wheel stops to facilitate the loading and unloading of dollies and the like. Like the receiving platform 5, the caster stoppers 50 are made of extruded aluminum. In this embodiment, the caster stoppers 50 are located at the rear of the receiving platform 5 (the base-end receiving platform 6) and extend in the left-right direction. They are used by standing upright behind a dolly loaded on the receiving platform 5. The caster stoppers 50 include a first caster stopper 50A located on the left side of the receiving platform 5, a second caster stopper 50B located on the right side of the receiving platform 5, and a third caster stopper 50C interposed between the first caster stopper 50A and the second caster stopper 50B. The first caster stopper 50A, the second caster stopper 50B, and the third caster stopper 50C extend laterally in the same straight line.

[0022] The first caster stopper 50A, the second caster stopper 50B, and the third caster stopper 50C extend as far as possible between the left and right side moldings 9 (or the left and right side guards, if side guards are present). The left-right length of the central third caster stopper 50C is set shorter than the distance between the left and right casters of a standard cart to be placed on the loading platform 5, so that the first caster stopper 50A can receive the left caster of a cart to be loaded on the loading platform 5, and the second caster stopper 50B can receive the right caster of a cart to be loaded on the loading platform 5. On the other hand, the left-right length of the third caster stopper 50C is set longer than the left-right width of the external dimensions of a transport machine, such as an AGV, used to transport a standard cart. Furthermore, in the case of an AGV that travels by gripping a cart with an arm, when pushing the cart onto the loading platform 5, there are cases where only the arm enters between the first caster stopper 50A and the second caster stopper 50B, and the main body of the AGV does not go beyond the position of the third caster stopper 50C. When considering such a case, the length in the left-right direction of the third caster stopper 50C may be shorter than the width of the AGV main body, as long as it is longer than the left-right width of the arm, i.e., the part that connects to the cart.

[0023] The first caster stopper 50A, the second caster stopper 50B, and the third caster stopper 50C have rear portions connected to the load receiving platform 5 via hinges 51, and front portions rotate up and down to change their position between an upright position and a lying position. Specifically, in this embodiment, the hollow portion 5a (the rearmost hollow portion 5a in this example) of the load receiving platform 5 (the tip load receiving platform 7) is open to the load receiving surface over the entire length of the load receiving platform 5 on both sides, and the first caster stopper 50A, the second caster stopper 50B, and the third caster stopper 50C are configured to open and close the upper opening of this hollow portion 5a between the left and right side moldings 9. With this configuration, in the laid-down position, the first caster stopper 50A, the second caster stopper 50B, and the third caster stopper 50C close the upper opening of the hollow portion 5a of the load receiving platform 5, as shown by the dashed line in Fig. 5, and form part of the load receiving surface of the load receiving platform 5. On the other hand, in the upright position, the first caster stopper 50A, the second caster stopper 50B, and the third caster stopper 50C protrude upward from the load receiving surface of the load receiving platform 5, as shown by the solid line in Fig. 5, and function as a rear wheel stopper. In the upright position, the first caster stopper 50A, the second caster stopper 50B, and the third caster stopper 50C stand in an inclined position toward the load receiving platform 3 (i.e., they are inclined upward toward the front).

[0024] The first and second caster stoppers 50A, 50B on the left and right sides are configured to be pushed up in the standing direction by a spring or other biasing means (not shown). For this reason, the platform lifting device 4 is provided with a locking device 53 that restrains the first and second caster stoppers 50A, 50B in a collapsed position. In this embodiment, the central third caster stopper 50C is not particularly biased by a spring or the like, and will collapse by itself under its own weight.

[0025] However, the third caster stopper 50C can be connected to the first caster stopper 50A via a switching mechanism 70 (FIG. 6). The mechanism that connects the third caster stopper 50C and the first caster stopper 50A can be designed differently as needed, but the switching mechanism 70 illustrated in this embodiment has a latch structure and includes a rotating shaft 71, a latch 72 extending from the rotating shaft 71, and an operating portion 73.

[0026] The rotation shaft 71 is rotatably supported by a bearing 75 that is disposed in the hollow portion 5a so as to be located on the rear side of the first caster stopper 50A. The rotation shaft 71 is preferably disposed so that its center coincides with the rotation center of the caster stopper 50 (the axis of the hinge 51 in this example), but it may be offset from the rotation center of the caster stopper 50.

[0027] Latch 72 is formed in an L-shape with arm 72a extending radially from rotating shaft 71 and tip 72b extending from the tip of the arm toward third caster stopper 50C. Like rotating shaft 71, latch 72 is also located on the back side of first caster stopper 50A.

[0028] The operating unit 73 includes a lever 73a that passes through a slit 52 extending laterally in the first caster stopper 50A, and a transmission unit 73b that connects the lever 73a to the rotating shaft 71 and transmits the movement of the lever 73a to the rotating shaft 71. In this example, the transmission unit 73b is L-shaped to avoid interference with a spring (e.g., a torsion bar) (not shown) that biases the first caster stopper 50A in the upright direction. The transmission unit 73b is located on the back side of the first caster stopper 50A, just like the rotating shaft 71. The lever 73a passes through the slit 52, with its tip protruding from the front side (the load-receiving surface side) of the first caster stopper 50A.

[0029] The rotating shaft 71, latch 72, and operating unit 73 are integrally configured, and when lever 73a is operated left or right along slit 52, the movement of lever 73a is transmitted to the rotating shaft 71 via transmission unit 73b, causing the rotating shaft 71 and latch 72 to slide left or right relative to bearing 75. This causes tip 72b of latch 72 to be inserted into or removed from block 76 provided on the back surface of third caster stopper 50C. As shown by the two-dot chain line in FIG. 6, tip 72b of latch 72 is inserted into block 76, thereby connecting the first caster stopper 50A and the third caster stopper 50C. As shown by the dashed line in FIG. 6, tip 72b of latch 72 is removed from block 76, thereby disconnecting the first caster stopper 50A and the third caster stopper 50C. 6 shows a switching mechanism 70 that switches between a connected state and a disconnected state between the first caster stopper 50A and the third caster stopper 50C on the left side of the load receiving platform 5, but a similar switching mechanism 70 is also provided on the right side of the load receiving platform 5, and the right switching mechanism 70 switches between a connected state and a disconnected state between the second caster stopper 50B and the third caster stopper 50C of the load receiving platform 5. However, one of these left and right switching mechanisms 70 is not necessarily required and can be omitted.

[0030] As described above, the third caster stopper 50C can be switched between a state in which it rises and falls in conjunction with at least one of the first caster stopper 50A and the second caster stopper 50B, and a state in which it falls independently. When the third caster stopper 50C is connected to at least one of the first caster stopper 50A and the second caster stopper 50B, the third caster stopper 50C rises up along with the first caster stopper 50A or the second caster stopper 50B by the force of the spring when the locking device 53 of the first caster stopper 50A or the second caster stopper 50B is released. Conversely, when the third caster stopper 50C is disconnected from both the first caster stopper 50A and the second caster stopper 50B, the third caster stopper 50C falls down by its own weight, regardless of the position of the first caster stopper 50A or the second caster stopper 50B. In this way, the third caster stopper 50C can be lowered independently of the first caster stopper 50A and the second caster stopper 50B.

[0031] In the laid-down state, the third caster stopper 50C forms a load receiving surface between the first and second caster stoppers 50A and 50B on the left and right, and even when the first and second caster stoppers 50A and 50B are upright, a transport machine such as an AGV can pass through the load receiving surface of the third caster stopper 50C to enter and exit the load receiving platform 5. In this way, the first and second caster stoppers 50A and 50B are arranged spaced apart on the left and right so that a load receiving surface is interposed between them.

[0032] -Posture detection device- The platform lifting / lowering device 4 is equipped with a posture detection device 60 that detects the posture of each of the first caster stopper 50A and the second caster stopper 50B, i.e., whether they are in a lying down posture or an upright posture. In this embodiment, the posture detection device 60 is installed on the left side of the first caster stopper 50A and on the right side of the second caster stopper 50B, as shown in FIG.

[0033] The attitude detection device 60 includes a stopper sensor 61 (FIG. 5), a bracket 62, and a target 65 (FIG. 5).

[0034] The stopper sensor 61 is a non-contact sensor for detecting the position of the first caster stopper 50A (or the second caster stopper 50B), and in this embodiment is attached to the loading platform 5 via a bracket 62 and is disposed inside the hollow portion 5a that is opened and closed by the caster stopper 50. The stopper sensor 61 may be, for example, an inductive proximity sensor, a capacitive proximity sensor, a magnetic proximity sensor, a distance meter that uses sound waves or a laser, or a photoelectric sensor. The stopper sensor 61 is connected to a control device (not shown) of the loading platform lifting device 4 via wiring (not shown), and the output signal of the stopper sensor 61 is input to the control device.

[0035] The bracket 62 is a component that holds the stopper sensor 61, and is provided on the first caster stopper 50A (or the second caster stopper 50B) and one of the load receiving platforms 5 (the load receiving platform 5 in this embodiment). In this embodiment, the bracket 62 is composed of a plate 63 and an L-shaped bracket 64. The plate 63 is located between the first caster stopper 50A (or the second caster stopper 50B) and the side molding 9, and is arranged so as to straddle the upper opening of the hollow portion 5a of the load receiving platform 5, which is opened and closed by the first caster stopper 50A (or the second caster stopper 50B), from front to back, and is fixed to the load receiving surface of the load receiving platform 5 with a plurality of fasteners S1 (screws, etc.). The L-shaped bracket 64 is fixed to the back surface of the plate 63 (the surface facing away from the load-receiving surface) with fasteners S2 (screws, etc.), and is located in the hollow portion 5a when the first caster stopper 50A (or the second caster stopper 50B) is in the laid-down position. A stopper sensor 61 is fixed to this L-shaped bracket 64 with fasteners S3 (screws, etc.). The stopper sensor 61 is attached to the load-receiving platform 5 by the bracket 62 with its detection surface facing inward in the width direction of the load-receiving platform 5, that is, facing the target 65 when the first caster stopper 50A (or the second caster stopper 50B) is in the laid-down position. The detection surface of the stopper sensor 61 is the surface that emits electromagnetic waves, etc., to detect the target 65. The stopper sensor 61 detects the target 65 when it approaches the detection surface.

[0036] The target 65 is a component to be detected by the stopper sensor 61, and is provided on the other of the first caster stopper 50A (or the second caster stopper 50B) and the loading platform 5 (the caster stopper in this embodiment), and is made of a different material from the first caster stopper 50A (or the second caster stopper 50B) and the loading platform 5. The target 65 is arranged so as to face the detection surface of the stopper sensor 61 when the first caster stopper 50A (or the second caster stopper 50B) is in a laid-down position. The target 65 is made of a material that allows the stopper sensor 61 to detect the target 65 over a longer distance than the material of the first caster stopper 50A (or the second caster stopper 50B) and the loading platform 5. The detection distance is the distance from the detection surface of the stopper sensor 61 to the target 65, and is the distance at which the stopper sensor 61 can detect the target 65. The material of the target 65 is selected depending on the detection method of the stopper sensor 61, and differs, for example, in electrical resistivity, dielectric constant, or magnetic force from the material of the caster stopper 50. In this embodiment, the caster stopper 50 and the loading platform 5 are made of aluminum, while the target 65 is made of a material (for example, steel such as carbon steel or alloy steel) that has a longer detection distance than aluminum.

[0037] Furthermore, the target 65 in this embodiment is a block- or plate-shaped member attached to the surface of the first caster stopper 50A (or the second caster stopper 50B) opposite the load receiving surface with fasteners such as screws or bolts (not shown). However, the target 65 is not necessarily limited to being attached to the first caster stopper 50A (or the second caster stopper 50B) with fasteners, and may be, for example, a coating such as paint or plating applied to the surface of the first caster stopper 50A (or the second caster stopper 50B) facing the stopper sensor 61. In this case, when comparing detection distances, it is sufficient that the coated first caster stopper 50A (or the second caster stopper 50B) is longer than the material of the first caster stopper 50A (or the second caster stopper 50B) and the load receiving platform 5. The detection surface of the target 65 (that is, the surface onto which the electromagnetic waves of the stopper sensor 61 are applied) is aligned roughly with the end surface of the first caster stopper 50A (or the second caster stopper 50B) in the left-right direction.

[0038] With the posture detection device 60 configured as described above, when the first caster stopper 50A (or the second caster stopper 50B) is in a lying position, the target 65 faces the stopper sensor 61, the stopper sensor 61 detects the target 65, and it is detected that the first caster stopper 50A (or the second caster stopper 50B) is in a lying position. Conversely, when the first caster stopper 50A (or the second caster stopper 50B) is in an upright position, the target 65 is outside the detection range of the stopper sensor 61 and is not detected, and this non-detection state can be used to detect that the first caster stopper 50A (or the second caster stopper 50B) is in an upright position.

[0039] -Opening and closing unit- The opening / closing unit is equipped with a gate cylinder (not shown) as an actuator for opening and closing the folding receiving platform 5. The gate cylinder is a double-acting hydraulic cylinder. Both ends of the gate cylinder are rotatably connected to the base receiving platform 6 and the tip receiving platform 7. For example, when the gate cylinder contracts while the receiving platform 5 is folded, the tip receiving platform 7 rotates backward relative to the base receiving platform 6, and the receiving platform 5 unfolds. Conversely, when the gate cylinder extends while the receiving platform 5 is unfolded, the tip receiving platform 7 rotates forward relative to the base receiving platform 6, and the receiving platform 5 is folded. However, the gate cylinder is not necessarily required, and the receiving platform 5 may be configured to require some manual operation for opening and closing.

[0040] -Work example- Figures 7 and 8 show examples of work. Figure 7 is a schematic diagram showing an example of work allocation in which a transport machine loads luggage from the ground onto a loading platform, and a worker carries the luggage from the loading platform back onto the loading platform. Figure 8 is a schematic diagram showing an example of work allocation in which a worker loads luggage from the loading platform onto a loading platform, and a transport machine carries the luggage from the loading platform back to the ground. Figures 7 and 8 show an example in which a worker is responsible for work on the loading platform, and a transport machine is responsible for work on the ground.

[0041] In the example of Figure 7, a load X placed on a trolley Y is loaded onto a receiving platform 5 on the ground by a conveying machine V (Figures 7(a) and 7(b)). After the conveying machine V loads the load X onto the receiving platform 5 and gets off the receiving platform 5, a worker operates an operating device (not shown) to raise the receiving platform 5 to the height of the platform 3 (Figure 7(c)), and carries the load from the receiving platform 5 onto the platform 3 (Figure 7(d)).

[0042] In the example of Fig. 8, the worker on the loading platform 3 places the cargo X on the cart Y and loads it from the loading platform 3 onto the receiving platform 5 (Fig. 8(a)), and operates the operating device to lower the receiving platform 5 to the ground (Figs. 8(b) and 8c)). The conveying machine V rises onto the receiving surface of the receiving platform 5 that has been lowered to the ground, loads the cargo X together with the cart Y, descends from the receiving platform 5, and carries the cargo X off the receiving platform 5 (Fig. 8(d)).

[0043] FIG. 9 is an explanatory diagram of the loading and unloading of a dolly onto a load-receiving platform by a conveying machine. When load X carried on dolly Y is loaded onto load-receiving platform 5 by conveying machine V, the locking device 53 is released from the lock on the first caster stopper 50A and the second caster stopper 50B, and the first caster stopper 50A and the second caster stopper 50B are left standing. Furthermore, the switching mechanism 70 described in FIG. 6 is operated to release the third caster stopper 50C from both the first caster stopper 50A and the second caster stopper 50B. As a result, the third caster stopper 50C falls down independently of the first caster stopper 50A and the second caster stopper 50B, forming part of the load-receiving surface. The third caster stopper 50C constituting a part of the load receiving surface functions as a workspace for the conveying machine V, and the conveying machine V can travel freely on the laid-down third caster stopper 50C.

[0044] In this state, as shown in Figures 7(a) and 7(b), when the conveying machine V starts loading the cargo X onto the cargo receiving platform 5, the conveying machine V passes between the first caster stopper 50A and the second caster stopper 50B, i.e., on the cargo receiving surface formed by the third caster stopper 50C, and drops the cargo X together with the cart Y into the center of the cargo receiving platform 5. In this case, as shown in Figure 9, the left and right casters Y1 on the rear side of the cart Y are received by the first caster stopper 50A and the second caster stopper 50B, preventing the cargo X from deviating rearward from the cargo receiving platform 5. After dropping off the cargo X, the conveying machine V passes between the first caster stopper 50A and the second caster stopper 50B, i.e., over the third caster stopper 50C, and leaves the cargo receiving surface.

[0045] As shown in Figure 8, when a conveying machine V carries out a load X from the loading platform 5, the conveying machine V can freely get on and off the loading surface by passing over the third caster stopper 50C between the first caster stopper 50A and the second caster stopper 50B.

[0046] -effect- (1) As described above, according to this embodiment, even when the first caster stopper 50A and the second caster stopper 50B are in an upright position, the third caster stopper 50C can be lowered so that the conveying machine V can travel over the third caster stopper 50C and pass between the first caster stopper 50A and the second caster stopper 50B, allowing the conveying machine V to freely get on and off the load receiving surface. This prevents the caster stoppers 50 from interfering with the load loading and unloading operation of the conveying machine V to the load receiving platform 5. Furthermore, the upright first caster stopper 50A and the second caster stopper 50B function as a wheel stop for the cart Y loaded on the load receiving platform 5. In this way, the caster stoppers 50 function appropriately while the work space for the conveying machine V can be secured.

[0047] (2) The third caster stopper 50C can be switched between a state in which it rises and falls in conjunction with at least one of the first caster stopper 50A and the second caster stopper 50B, and a state in which it falls independently. By connecting the third caster stopper 50C to at least one of the first caster stopper 50A and the second caster stopper 50B, the third caster stopper 50C can be raised together with at least one of the first caster stopper 50A and the second caster stopper 50B. By raising all of the first caster stopper 50A, the second caster stopper 50B, and the third caster stopper 50C, a wheel stopper formed by the caster stoppers 50 can be formed across the entire width of the load receiving surface at the rear of the load receiving platform 5. The third caster stopper 50C can be used in different ways, such as by lowering it when loading and unloading work is performed by the conveying machine V, and by raising it when loading and unloading work is performed by a worker as in the conventional case.

[0048] 7 to 9 show an example in which a low-floor type conveying machine V that slips under the trolley Y is used, but the conveying machine V is not limited to the low-floor type and may be, for example, another type of AGV such as a towing type. For example, when the trolley Y is conveyed by a towing type conveying machine V, when loading the trolley Y onto the loading platform 5, the conveying machine V pushes the trolley Y forward to carry it onto the loading platform 5, and when unloading the trolley Y from the loading platform 5, the conveying machine V pulls the trolley Y backward to carry it out of the loading platform 5.

[0049] Second Embodiment Fig. 10 is an explanatory diagram of the loading and unloading operation of a carriage by a conveying machine onto a receiving platform provided in a receiving platform lifting device according to a second embodiment of the present invention. Fig. 10 corresponds to Fig. 9 of the first embodiment. In Fig. 10, elements similar to those in the first embodiment are given the same reference numerals as those in the previously mentioned drawings, and their explanations will be omitted.

[0050] This embodiment differs from the first embodiment in that the caster stoppers 50 include a first caster stopper 50D located at the rear of the load receiving platform 5 and a second caster stopper 50E located in front of the first caster stopper 50D. In the first embodiment, the first caster stopper 50A and the second caster stopper 50B are arranged on the left and right, whereas the first caster stopper 50D and the second caster stopper 50E of this embodiment are arranged at a distance from each other in the front and rear so that a load receiving surface is interposed between them.

[0051] The first caster stopper 50D on the rear side is disposed in a position corresponding to the caster stopper 50 of the first embodiment. The first caster stopper 50D may have a configuration similar to the caster stopper 50 of the first embodiment, but in this embodiment, the entire caster stopper 50D is configured to rise and fall integrally. Therefore, the first caster stopper 50D is not equipped with a switching mechanism 70.

[0052] The front second caster stopper 50E is located in the front half of the load receiving platform 5 (front load receiving platform 7), and extends left and right across the center of the load receiving surface of the load receiving platform 5 in the left-right direction. Except for the placement, the second caster stopper 50E is configured in the same way as the first caster stopper 50D, including the accompanying posture detection device 60 and locking device 53. The front-to-rear distance between the first caster stopper 50D and the second caster stopper 50E is approximately the same as the distance between the front and rear casters of a standard trolley Y to be placed on the load receiving platform 5, for example.

[0053] In other respects, this embodiment is similar to the first embodiment.

[0054] In this embodiment, when the cargo X placed on the dolly Y is loaded onto the cargo receiving platform 5 by the conveying machine V, the rear first caster stopper 50D is restrained in a laid-down state by the locking device 53, and the front second caster stopper 50E is left standing by releasing the lock from the locking device 53. In this embodiment, the dolly Y is conveyed by, for example, a towing-type conveying machine V.

[0055] In this state, as shown in Figures 7(a) and 7(b), when the conveying machine V starts loading the cargo X onto the receiving platform 5, the conveying machine V pushes the dolly Y loaded with the cargo X onto the receiving surface of the receiving platform 5, moves forward until the front caster Y2 of the dolly Y overcomes the second caster stopper 50E, and then lowers the cargo X together with the dolly Y onto the receiving surface with the casters Y2, Y1 of the dolly Y positioned in front of and behind the second caster stopper 50E. As a result, as shown in Figure 10, the left and right casters Y2 on the front side of the dolly Y are received by the second caster stopper 50E, preventing the cargo X from departing rearward from the receiving platform 5. After lowering the cargo X, the conveying machine V moves backward and away from the receiving platform 5.

[0056] 8, when the transport machine V carries the package X off the receiving platform 5, the first caster stopper 50D and the second caster stopper 50E are first laid down and locked. Then, the transport machine V moves backward, pulling the cart Y, and carries the package X off the receiving platform 5.

[0057] In this embodiment, too, by laying down the first caster stopper 50D and raising the second caster stopper 50E, the caster stopper 50 is prevented from obstructing the loading and unloading of cargo X onto the receiving platform 5 by the conveying machine V, and the conveying machine V can load and unload cargo X onto the receiving platform 5.

[0058] In addition, in this embodiment, a conveying machine V having a relatively wide vehicle width can also be applied.

[0059] <Additional remarks> The present invention is not limited to the above-described embodiments and may include various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. For example, it is possible to replace some of the configurations with other configurations. It is also possible to delete some of the configurations of the embodiments or add other configurations.

[0060] For example, in the first embodiment, a configuration in which the third caster stopper 50C is interposed between the first caster stopper 50A and the second caster stopper 50B is illustrated, but the third caster stopper 50C can also be omitted, as shown in FIG. 11 . Furthermore, the switching mechanism 70 is illustrated as having the operating unit 73 (lever 73a) positioned on the outer side of the first caster stopper 50A and the second caster stopper 50B in the vehicle width direction, but the operating unit 73 (lever 73a) may be positioned on the inner side of the first caster stopper 50A and the second caster stopper 50B in the vehicle width direction. In this case, the mechanism between the operating unit 73 and the third caster stopper 50C can be omitted, simplifying the configuration of the switching mechanism 70. Furthermore, although the switching mechanism 70 is illustrated as being manually operated, it may also be driven by electric, hydraulic, or other power.

[0061] Furthermore, in the above embodiment, the present invention has been described as being applied to an underfloor storage-type loading platform lifting device 4 that stores the loading platform 5 under the vehicle frame 1. However, the present invention can also be applied to other types of loading platform lifting devices. For example, some loading platform lifting devices have a loading platform that stands upright along the wall of the vehicle's loading platform when stored, but that extends horizontally and rises and falls along a vertical post when in use. Furthermore, even if the loading platform is raised and lowered via a parallel link, like the loading platform lifting device of this embodiment, some loading platforms do not retract into the lower part of the vehicle frame but instead assume a storage position in which the loading platform stands upright along the wall of the vehicle's loading platform. Because the present invention relates to interlock control of the lifting and lowering operation of the loading platform 5, it can be applied regardless of the loading platform's lifting and lowering method or storage method, and can achieve the same effects as the above embodiment.

[0062] Furthermore, in the above embodiment, an example has been described in which the stopper sensor 61 is used to detect the posture of the caster stopper 50 using electromagnetic waves, but the type and position of the sensor that detects the posture of the caster stopper 50 can be changed as appropriate. For example, a limit switch can be used as the stopper sensor 61, and a camera can be used as the posture detection device 60. [Explanation of symbols]

[0063] 4...load receiving platform lifting device, 5...load receiving platform, 50...caster stopper, 50A...first caster stopper (caster stopper), 50B...second caster stopper (caster stopper), 50C...third caster stopper (caster stopper), 50D...first caster stopper (caster stopper), 50E...second caster stopper (caster stopper), 70...switching mechanism, V...conveying machine, X...baggage

Claims

1. In a loading platform lifting device for lifting and lowering a loading platform relative to a vehicle, A caster stopper is provided on the loading platform, The caster stoppers include a first caster stopper and a second caster stopper located on the left and right sides, respectively, at the rear of the loading platform, The first caster stopper and the second caster stopper are arranged laterally spaced apart so that a load receiving surface is interposed between them. A loading platform lifting device characterized by the above.

2. The loading platform lifting device according to claim 1, a third caster stopper interposed between the first caster stopper and the second caster stopper; The third caster stopper in the collapsed state constitutes the load receiving surface between the first caster stopper and the second caster stopper. A loading platform lifting device characterized by the above.

3. The loading platform lifting device according to claim 2, The loading platform lifting device is characterized in that the third caster stopper can be lowered independently of the first caster stopper and the second caster stopper.

4. The loading platform lifting device according to claim 2 or 3, A loading platform lifting device characterized in that the third caster stopper is switchable between a state in which it rises and falls in conjunction with at least one of the first caster stopper and the second caster stopper, and a state in which it falls independently.

5. In a loading platform lifting device for lifting and lowering a loading platform relative to a vehicle, A caster stopper is provided on the loading platform, The caster stoppers include a first caster stopper located at the rear of the loading platform and a second caster stopper located in front of the first caster stopper, The first caster stopper and the second caster stopper are arranged at a distance from each other in the front-rear direction so that a load receiving surface is interposed between them. A loading platform lifting device characterized by the above.

6. The loading platform lifting device according to claim 5, The loading platform lifting device is characterized in that the second caster stopper is located in the front half of the loading platform.

7. The loading platform lifting device according to claim 5 or 6, A loading platform lifting device characterized in that the second caster stopper extends left and right across the center of the loading surface of the loading platform in the left-right direction.

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