Unmanned forklift and carrying method

Abstract

The invention provides an unmanned forklift and a carrying method which can safely and efficiently pick and place goods even in a narrow roadway. The unmanned forklift comprises a chassis used for walking, and the chassis can walk in the direction perpendicular to the picking direction; a gantry assembly having a gantry supported on the chassis so as to be able to move back and forth in the pickup direction; and a fork assembly which is supported on the gantry so as to be capable of moving up and down and which has a fork, the fork being located on the front side of the gantry as viewed in the pickup direction, at least a part of the chassis being also located on the front side of the gantry, the fork having: a main body part; and the forking part can slide and stretch out and draw back relative to the main body part.

Description

Technical Field

[0001] The present disclosure relates to an unmanned forklift and a handling method. Background Art

[0002] With the rapid development of modern logistics, efficient warehouse space utilization has become a key market concern. To maximize storage density, more and more warehouses are adopting dense container layouts, which requires significantly reduced aisle widths. Against this backdrop, unmanned forklifts that use forks to access cargo from the front face a significant limitation: Because they must access cargo from the front, forklifts entering the aisle must turn during the pickup and placement process to ensure their forks are aligned with the cargo being picked up. This turning maneuver inevitably requires a wider aisle, making these forklifts difficult to adapt to the increasingly narrow aisle conditions.

[0003] To address this challenge, the applicant pioneered a solution in the industry using a side-fork unmanned forklift. This type of side-fork forklift innovatively positions the forks on the side, allowing the forklift's pickup direction to be different (perpendicular) from the forklift chassis's travel direction. This allows for cargo pickup and placement operations without requiring steering within the work lane. This type of side-fork unmanned forklift may include a mast assembly and a fork device mounted on the mast assembly. The fork can move up and down along the mast assembly to locate pallets at different heights, completing cargo storage and retrieval operations.

[0004] It is understandable that side-fork unmanned forklifts face some technical difficulties in actual application that do not arise with upright forklifts themselves. First, the narrow aisle environment constrains the size of the forklift chassis, and the size of the chassis constrains the size of the forks, which in turn constrains the extension length of the forks, limiting its operating range. For example, the mast structure itself occupies a certain width of space in the direction of cargo picking, and this structural occupation further compresses the available fork length. Therefore, this makes it difficult for existing side-fork forklifts to effectively complete the storage and retrieval operations of cargo with general specifications. For example, when handling standard pallets, the forks often do not extend deep enough to fully accommodate the pallet, thus affecting operational efficiency and safety. In other words, there is still considerable room for technical development in the current side-fork forklifts.

[0005] In order to address the huge demand for high-density warehousing upgrades, it is still necessary to develop solutions for the specific technical route of side-fork forklifts (that is, those that can fully adapt to narrow aisle working environments) to achieve the higher goal of being able to pick up and place goods safely and efficiently. Summary of the Invention

[0006] The present disclosure is completed in view of the above-mentioned objectives, and its purpose is to provide an unmanned forklift and a transportation method that can safely and efficiently pick up and place goods even in narrow aisles.

[0007] A first aspect of the present disclosure provides an unmanned forklift, comprising: a chassis for walking, the chassis being capable of walking in a direction perpendicular to a picking direction; a gantry assembly, the gantry assembly having a gantry supported on the chassis so as to be movable back and forth in the picking direction; and a fork assembly, the fork assembly being supported on the gantry so as to be movable up and down and having a fork, wherein, viewed along the picking direction, the fork is located at the front side of the gantry, and at least a portion of the chassis is also located at the front side of the gantry, the fork comprising: a main body; and a fork-picking portion, the fork-picking portion being capable of sliding and retracting relative to the main body.

[0008] According to the first aspect of the present disclosure, the unmanned forklift comprises a mast supported on a chassis for reciprocating movement in a pickup direction, and a fork positioned in front of the mast. The fork's pick-up portion is also capable of sliding and retracting relative to the main body. This allows the fork's pick-up portion to extend sufficiently toward the shelf, particularly in narrow aisles such as those with densely packed containers, making it easy to retrieve and place cargo from deep within the container.

[0009] More specifically, when the fork portion slides and retracts relative to the main body, when the fork portion is extended, a portion of its length overlaps with the main body to support the main body, and by enabling the door frame to be supported on the chassis by moving back and forth in the picking direction, even if a portion of its length overlaps with the main body when the fork portion is extended, it is easy to pick up and put goods from deep inside.

[0010] In addition, if the mast is fixedly supported near the rear end of the chassis in the picking direction, and only the forks are extended and retracted, the fork's lever arm will become longer when taking cargo of the same depth, resulting in higher strength requirements for the forks. Here, "depth" refers to the position of the cargo farthest from the forklift along the picking direction. To address this problem, in the structure of the unmanned forklift described above, at least a portion of the chassis is located in front of the mast, allowing the mast to partially move within the range of the chassis in the picking direction. By partially moving the mast within the range of the chassis in the picking direction, the fork's lever arm for picking and placing cargo can be effectively reduced, reducing the strength requirements for the forks, while at the same time achieving sufficient reach.

[0011] Furthermore, compared to, for example, a situation where the mast is moved further forward than the chassis (e.g., the mast itself or other components attached to it extend forward beyond the chassis in the picking direction), having at least a portion of the chassis located in front of the mast also helps reduce counterweight and eliminates the need for structures such as outriggers (this significantly improves the forklift's flexibility in picking up cargo and effectively simplifies its structure). Furthermore, having at least a portion of the chassis located in front of the mast improves chassis stability. This structure is particularly advantageous for applications involving the picking up of platform-shaped pallets located on the ground.

[0012] In one embodiment, the gantry assembly further includes a gantry moving portion, the gantry being supported on the chassis via the gantry moving portion so as to be movable back and forth in the picking direction, the gantry moving portion having a free end further forward than the gantry, and the range of movement of the gantry and the gantry moving portion including the free end in the picking direction does not exceed the front and rear ends of the chassis in the picking direction. According to the above structure, the counterweight used to balance the weight of the forked transport object on the unmanned forklift can be reduced.

[0013] In one embodiment, the gantry moving part moves together with the gantry, and the gantry moving part includes a supporting part connected to or integrally formed with the gantry, and the supporting part is in sliding contact or rolling contact with the chassis.

[0014] In one embodiment, the support portion and the fork do not overlap in the vertical direction. According to the above structure, the support portion does not occupy the descending height of the fork.

[0015] In one embodiment, when the fork is lowered to its lowest position, the lower surface of the fork-picking portion is lower than the upper surface of the support portion. According to the above structure, when the fork is lowered to its lowest position, the height of the fork can be lowered to a level lower than the upper surface of the support portion, thereby achieving a lower height for picking up and placing goods.

[0016] In one embodiment, the chassis is provided with a notch through which the forking portion of the fork passes, the sidewalls of the notch are provided with tracks, the support portion is equipped with rollers and supported on the tracks via the rollers, and the travel of the gantry is shorter than the length of the notch in the picking direction. With this structure, the space in the notch can be fully utilized to support the gantry's moving portion.

[0017] In one embodiment, the support portion includes a front end and a rear end along the picking direction, and the plurality of rollers are provided, including a first roller mounted near the front end and a second roller mounted near the rear end. With this structure, the gantry moving portion can be stably supported with a simple structure.

[0018] In one embodiment, the chassis has a bottom plate, and the supporting portion is supported on the bottom plate so as to be movably along the picking direction.

[0019] In one embodiment, the ratio of the dimension of the support portion in the picking direction to the width of the chassis in the picking direction is 0.35 to 0.75. According to the above structure, the counterweight for balancing the weight of the forked transport object on the unmanned forklift can be reduced or eliminated.

[0020] Preferably, the ratio of the dimension of the support portion in the picking direction to the width of the chassis in the picking direction is 0.40 to 0.70. This can better achieve the effect of reducing or eliminating counterweight, and is particularly suitable for unmanned forklifts that can pick up and place goods at different heights in the vertical direction.

[0021] In one embodiment, the unmanned forklift includes a limiting mechanism provided on at least one of the mast assembly and the chassis, the limiting mechanism being configured to limit the mast's movable portion from moving beyond the front end of the chassis. This configuration can prevent undesirable situations caused by the mast's movable portion accidentally moving beyond the front end of the chassis.

[0022] In one embodiment, the limiting mechanism includes a first portion and a second portion, wherein the first portion is provided on the gantry assembly and the second portion is provided on the chassis. Before the gantry moving portion moves beyond the front end of the chassis, the first portion is engaged with the second portion. This configuration can prevent adverse conditions caused by the gantry moving portion accidentally moving beyond the front end of the chassis with a simple structure.

[0023] In one embodiment, the second portion is a stopper provided on the chassis in front of the gantry moving portion, and the front end of the gantry moving portion becomes the first portion. According to the above structure, the gantry moving portion itself can be used to form part of the stopper mechanism, which can reduce components and reduce costs.

[0024] In one embodiment, the unmanned forklift includes a driving mechanism, which causes the gantry to move in the picking direction, and the limiting mechanism includes: a detection device, which detects information related to the moving distance of the gantry moving part; and a control part, which controls the action of the driving mechanism based on the detection result of the detection device to limit the movement of the gantry moving part beyond the front end of the chassis.

[0025] In one embodiment, the detection device is a proximity switch or a photoelectric sensor.

[0026] In one embodiment, the driving mechanism includes: a gear rotatably supported on one side of the gantry assembly and the chassis; a rack meshing with the gear and installed on the other side of the gantry assembly and the chassis; and a motor driving the gear to rotate, and the detection device is an encoder for detecting the rotation of the gear.

[0027] In one embodiment, an unmanned forklift includes a rear end limiter mechanism disposed on at least one of the mast assembly and the chassis, the rear end limiter mechanism being configured to limit rearward movement of the mast moving portion beyond a predetermined position. This configuration can prevent adverse conditions caused by the mast moving portion accidentally moving backward beyond a predetermined position.

[0028] In one embodiment, an unmanned forklift includes a drive mechanism having a drive source for moving the gantry in the picking direction, the rear end limit mechanism including a control unit and a first detection device, the first detection device being provided between the gantry assembly and the chassis, the first detection device including: a first sensor provided on the chassis; and a trigger plate provided on the gantry assembly and moving together with the gantry and the gantry moving portion, wherein when the trigger plate moves to a distance less than a specified distance from the first sensor and triggers the first sensor, the first sensor sends a first signal to the control unit, and the control unit, upon receiving the first signal, stops the drive source. According to the above structure, the gantry moving portion can be automatically prevented from accidentally moving backward beyond a specified position.

[0029] In one embodiment, the ratio of the travel of the gantry in the picking direction to the width of the chassis in the picking direction is 0.7 or less. This structure reduces the counterweight required to balance the weight of the forked object on the unmanned forklift, effectively avoiding various hidden dangers caused by center of gravity offset when picking and placing goods, especially goods of standard dimensions. Furthermore, the efficiency of the picking and placing process can be optimized.

[0030] In one embodiment, the forks are provided in plurality, and the chassis is provided with a plurality of notches corresponding to the plurality of forks, each of the plurality of notches is open forward in the picking direction and is passed through in the up-down direction at least at the portion corresponding to the fork, so as to allow the forking portion of the corresponding fork to pass through. According to the above structure, shorter transport objects (such as pallets) placed on the ground can be inserted at a height close to the ground. In addition, compared with the case where a whole notch is provided corresponding to the plurality of forks, it is possible to avoid the notch being too large and the chassis being unstable, thereby improving the stability of the chassis. It is also possible to increase the installation space for electrical components, thereby easily reducing the overall volume of the chassis and reducing the vehicle's rotation diameter.

[0031] In one embodiment, a second sensor is mounted on the front end of the chassis to identify the contour of a pallet placed on the ground. This eliminates the need for a sensor on the front end of the fork's pick-up portion to retrieve a pallet placed on the ground. This allows for a thinner fork design, allowing for wider pallet types to be used, and allows for pallet insertion at a lower height.

[0032] In one embodiment, two forks are arranged in a direction perpendicular to the picking direction, and two notches are provided corresponding to the two forks.

[0033] In one embodiment, when the mast is at the rear end of its travel and the forking portion is retracted, the projection of the fork is within the range of the chassis, thereby preventing the fork from interfering with surrounding objects when the chassis is moving.

[0034] In one embodiment, an unmanned forklift includes a drive mechanism that moves the gantry in the picking direction, the drive mechanism including: a gear rotatably supported on one side of the gantry assembly and the chassis; a rack meshing with the gear and mounted on the other side of the gantry assembly and the chassis; and a motor that drives the gear to rotate, or the drive mechanism includes a sprocket chain transmission mechanism, or the drive mechanism includes a synchronous belt transmission mechanism, or the drive mechanism includes an electric cylinder, or the drive mechanism includes a hydraulic cylinder.

[0035] In one embodiment, the chassis includes a loading portion for carrying the transported object, and at least a portion of the loading portion is located in front of the gantry. According to the above structure, the area of the loading portion is increased, and the transported object can be carried more stably.

[0036] In one embodiment, a stop bar projecting upward is provided at the rear end of the forking portion. According to the above structure, it is possible to prevent the transported object forked by the forking portion from hindering the extension and contraction of the forking portion.

[0037] In one embodiment, the gantry comprises: a first gantry; and a second gantry, wherein the second gantry is vertically supported on the first gantry, and the fork assembly is vertically supported on the second gantry. With this structure, it is possible to pick up and place goods at a variety of heights.

[0038] A second aspect of the present disclosure provides a transporting method, which uses any of the above-mentioned unmanned forklifts to transport a transport object, including a picking-up step, transporting the transport object picked up by the fork to the loading portion on the chassis, wherein the picking-up step includes: after the forking portion of the fork that has picked up the transport object begins to retract, the mast moves to the rearmost end of the moving stroke, or, wherein the picking-up step includes: while the forking portion of the fork that has picked up the transport object begins to retract, the mast starts to move to the rearmost end of the moving stroke. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 1 is a perspective view showing an unmanned forklift according to an embodiment of the present disclosure.

[0040] Figure 2 1 is a perspective view showing an unmanned forklift according to an embodiment of the present disclosure.

[0041] Figure 3 1 is a perspective view showing an unmanned forklift according to an embodiment of the present disclosure.

[0042] Figure 4 FIG. 1 is a top view of an unmanned forklift according to an embodiment of the present disclosure.

[0043] Figure 5 1 is a perspective view showing a chassis of an unmanned forklift according to an embodiment of the present disclosure.

[0044] Figure 6 It is a partial bottom view of the chassis showing the forks and the vicinity of the forks.

[0045] Figure 7 FIG. 1 is a partial front view of an unmanned forklift according to an embodiment of the present disclosure.

[0046] Figure 8 1 is an exploded perspective view showing a mast, a mast moving part, and a fork of an unmanned forklift according to an embodiment of the present disclosure.

[0047] Figure 9 1 is a perspective view showing a mast moving portion of an unmanned forklift according to an embodiment of the present disclosure.

[0048] Figure 10 FIG. 1 is a side view showing a fork of an unmanned forklift according to an embodiment of the present disclosure.

[0049] Figure 11 FIG. 1 is a top view of an unmanned forklift according to an embodiment of the present disclosure.

[0050] Figure 12 1 is a perspective view showing a gear and a rack of an unmanned forklift according to an embodiment of the present disclosure.

[0051] Figure 13 1 is a perspective view showing a first detection device of an unmanned forklift according to an embodiment of the present disclosure.

[0052] Figure 14 1 is a perspective view showing a first detection device of an unmanned forklift according to an embodiment of the present disclosure.

[0053] (Explanation of Symbols)

[0054] 10 chassis; 11 chassis body; 12 notch; 14 second sensor; 20 gantry assembly; 21 gantry; 22 gantry moving portion; 23 connecting frame; 24 pulley; 25 flexible cable; 30 fork assembly; 31 fork; 32 base; 41 oil cylinder; 51, 52 rails; 61 roller; 70 gantry drive mechanism (drive mechanism); 71 gear; 72 rack; 80 limit mechanism; 81, 82 limit blocks; 90 rear end limit mechanism; 91 first sensor; 92 trigger plate; 101 first chassis portion; 102 second chassis portion; 103 third chassis portion; 111 chassis housing; 111a top plate; 111b bottom plate; 111c side plate; 111c1 rear side plate; 112 frame; 112a Crossbeam; 112b rib; 121 first notch; 122 second notch; 211 first door frame; 212 second door frame; 213 cover; 221, 222 support portion; 221a, 222a first plate; 221b, 222b second plate; 221c, 222c extension portion; 221d third plate; 223 connecting plate; 311 main body; 311a third portion; 311b fourth portion; 312 fork portion; 312a fork portion housing; 313 stop bar; 611 first roller; 612 second roller; 1211, 1212, 1221, 1222 side walls; G through portion; L width of chassis in the picking direction; L1 dimension of the support portion in the picking direction; S storage support portion DETAILED DESCRIPTION

[0055] The following describes the technical solutions of the embodiments and modifications of the present disclosure with reference to the accompanying drawings. The scope of the present disclosure is not limited to the following embodiments and modifications, and can be arbitrarily modified within the scope of the technical concept of the present disclosure. Furthermore, in the following drawings, to facilitate understanding of each structure, the actual structure may be different from the scale, quantity, etc. in each structure. The same or equivalent parts in the drawings are denoted by the same reference numerals, and repeated descriptions are omitted.

[0056] <First embodiment>

[0057] Next, an unmanned forklift (hereinafter sometimes referred to as simply “forklift”) 100 according to a first embodiment will be described.

[0058] In the drawings, for ease of understanding, the Z direction, the X direction, and the Y direction that intersect with each other are appropriately shown.

[0059] The Z direction is defined based on the state in which the automated forklift 100 is set on the ground in a usable state. The Z direction is the up-down direction of the automated forklift 100. The X direction is, for example, the picking direction.

[0060] One direction and the other direction in the Z direction are also referred to as one direction Z1 and the other direction Z2. In this embodiment, the one direction Z1 and the other direction Z2 are the upper and lower sides of the automated forklift 100 in use.

[0061] One direction and the other direction in the X direction are also referred to as one direction X1 and the other direction X2. In this embodiment, in the unmanned forklift 100 in use, the X direction is a direction perpendicular to the up-down direction, the one direction X1 is the front when viewed from the picking direction, and the other direction X2 is the opposite direction of the one direction X1, i.e., the rear.

[0062] One direction and the other direction in the Y direction are also referred to as one direction Y1 and the other direction Y2. In this embodiment, in the unmanned forklift 100 in use, the Y direction is perpendicular to the vertical direction and the X direction (pickup direction). In this specification, "parallel direction" also includes substantially parallel directions, and "perpendicular direction" also includes substantially perpendicular directions.

[0063] (Schematic structure of an unmanned forklift)

[0064] Figure 1 1 is a perspective view showing the unmanned forklift 100 according to the first embodiment of the present disclosure, showing a state in which the mast 21 is located at an initial position and (the forking portion 312 of) the fork 31 is retracted. Figure 2 1 is a perspective view showing the unmanned forklift 100 , showing a state in which the mast 21 has moved to the front in the picking direction (one side X1 in the X direction) relative to the initial position and the fork 31 (the forking portion 312 thereof) has been extended. Figure 3 1 is a perspective view showing the unmanned forklift 100 , showing a state in which the second mast 212 is raised and the fork assembly 30 is raised. Figure 4 1 is a plan view showing the unmanned forklift 100 , showing a state in which the mast 21 is located at an initial position and the forks 31 (the forking portions 312 thereof) are retracted. Figure 5 1 is a perspective view showing the chassis 10 of the unmanned forklift 100 . Figure 6 It is a partial bottom view of the chassis 10 as viewed from below (the other direction Z2 in the Z direction) showing the fork 31 and the vicinity thereof, and shows a state where the mast 21 is at the initial position and the fork 31 (the forking portion 312 thereof) is retracted. Figure 7 1 is a partial front view of the automated forklift 100 as viewed from one side X1 in the X direction. Figure 8It is an exploded perspective view showing the mast 21 , the mast moving unit 22 , and the forks 31 of the automated forklift 100 . Figure 9 It is a perspective view showing the mast moving unit 22 of the automated forklift 100 . Figure 10 3 is a side view showing the fork 31 . Figure 11 1 is a plan view showing the unmanned forklift 100 , showing a state in which the mast 21 has moved to a position further forward in the picking direction (one side X1 in the X direction) than the initial position and the fork 31 (the forking portion 312 thereof) has been extended. Figure 12 It is a perspective view showing the gears and rack of the automated forklift 100 . Figure 13 1 is a perspective view showing a first detection device of the automated forklift 100 . Figure 14 1 is a perspective view showing a first detection device of an unmanned forklift 100. Figures 1 to 14 Some parts are omitted in the illustration.

[0065] The driverless forklift 100 is a side-lift, driverless forklift capable of traveling in a direction perpendicular to the pickup direction. "Driverless" here means that the forklift's movement is independent of a driver's control. The driverless forklift 100 transports objects. More specifically, the driverless forklift 100 picks up and places objects. Examples of transported objects include loaded pallets and empty pallets. Examples include zigzag pallets and chuan-shaped pallets.

[0066] The unmanned forklift 100 includes a chassis 10, a mast assembly 20 and a fork assembly 30. The mast assembly 20 has a mast 21 supported on the chassis 10 so as to be movable back and forth in the picking direction (X direction). The fork assembly 30 is supported on the mast 21 so as to be movable up and down, and has a fork 31. The fork 31 has: a main body 311; and a fork picking portion 312. The fork picking portion 312 can slide and retract relative to the main body 311. The fork picking portion 312 can be retracted and retracted away from the mast forward (one side X1 in the X direction) or backward toward the mast (the other side X2 in the X direction) in the picking direction. The structures of the fork picking portion and the main body can at least partially overlap up and down in space.

[0067] In this embodiment, a fork is used in which the fork portion 312 can slide and extend telescopically relative to the main body 311 (similar to telescopic sliding and extending). However, the fork is not limited to this embodiment. Alternatively, the fork portion 312 and the main body 311 are not nested together, but are merely (at least partially) stacked in the vertical direction. In this state, the fork portion 312 can also slide and extend relative to the main body 311.

[0068] The unmanned forklift 100 further includes a chassis driving mechanism for moving the chassis, a mast driving mechanism 70 (equivalent to the "driving mechanism" of the present disclosure) for moving the mast 21 in the picking direction, and a fork driving mechanism for extending and retracting the forking portion 312 of the fork 31.

[0069] (Chassis)

[0070] The chassis 10 is used for walking. The chassis 10 has a chassis body 11 and a plurality of wheels 15 for walking installed on the chassis body. Figure 7 As shown. The chassis body 11 is supported on the ground via a plurality of wheels 15. The plurality of wheels 15 jointly support the chassis body 11 so that it leaves the ground. The wheels 15 are mounted on the bottom of the chassis body 11, and support the chassis 10 on the ground in a manner such that it can walk. For example, the wheels 15 for walking may include one or more drive wheels and one or more universal wheels, so that the chassis 10 can walk on the ground. In this case, the unmanned forklift 100 also includes: a driving source such as a motor for driving the above-mentioned drive wheels to rotate (not shown); and a walking controller (not shown) for controlling the action of the driving source for walking.

[0071] In this embodiment, the wheels 15 for travel include two drive wheels and four universal wheels. By aligning the rotational axes of the drive wheels with the pickup direction, travel in the Y direction is possible. This allows the chassis 10 to travel perpendicular to the pickup direction (X direction). Turning can also be achieved by using a speed differential between the two drive wheels (e.g., by braking one drive wheel).

[0072] like Figure 1 and Figure 5 As shown, the chassis body 11 includes: a chassis housing 111 ; a frame 112 combined with the chassis housing 111 ; and components (not shown) housed in the chassis housing 111 .

[0073] The chassis housing 111 includes: a top plate 111a; a bottom plate 111b located below the top plate 111a (on the other side Z2 in the Z direction); and a side plate 111c connecting the top plate 111a and the bottom plate 111b. The side plate 111c includes a rear side plate 111c1 constituting the rear (on the other side X2 in the X direction) surface of the chassis body 11. A storage space is formed inside the chassis housing 111. Although not shown in detail, the components housed in the chassis housing 111 include, for example: an oil pump, a hydraulic motor, an oil tank, and a controller for the oil system of the hydraulic system for raising and lowering the second gantry 212 of the gantry 21 described later relative to the first gantry 211; a travel controller for travel; and a power module, etc.

[0074] The frame 112 includes a crossbeam 112a and a plurality of ribs 112b. The crossbeam 112a extends along the Y direction. The rear side panel 111c1 is connected to the crossbeam 112a via the plurality of ribs 112b.

[0075] like Figure 5 As shown, in this embodiment, the chassis body 11 includes a first chassis portion 101, a second chassis portion 102, and a third chassis portion 103. The first chassis portion 101, the second chassis portion 102, and the third chassis portion 103 are arranged in sequence in the Y direction. The first chassis portion 101, the second chassis portion 102, and the third chassis portion 103 are connected to each other by a frame 112 and a rear side plate 111c1. As a result, the chassis 10 as a whole is "E-shaped" when viewed from above in the vertical direction (Z direction). In addition, on the rear side (the other side X2 in the X direction) in the picking direction, the bottom plate 111b is connected to each other between the first chassis portion 101 and the second chassis portion 102, and between the second chassis portion 102 and the third chassis portion 103. The first chassis portion 101, the second chassis portion 102, and the third chassis portion 103 are each supported on the ground by two wheels 15. For example, the second chassis portion 102 is supported on the ground by a drive wheel.

[0076] The chassis 10 is provided with a plurality of notches 12 corresponding to the plurality of forks 31 described later. Figure 5 As shown, each of the plurality of notches 12 opens forward in the picking direction (one side X1 in the X direction), and penetrates at least in the portion corresponding to the fork 31 in the vertical direction, forming a through portion G for the corresponding fork 31 to pass through. Here, "penetrating in the vertical direction at the portion corresponding to the fork to allow the corresponding fork to pass through" means that, when the mast 21 is in the initial position and the fork 31 is retracted, the through portion G in the notch 12 coincides with the projection of the portion of the fork used to fork the transported object (the fork 312), as shown in FIG. Figure 6 As shown. Here, "projection" refers to projecting the relevant components onto a plane perpendicular to the vertical direction (Z direction). Because the notch 12 opens forward in the picking direction (X direction) and penetrates vertically at least in the portion corresponding to the fork 31, when the mast 21 is in its initial position, the portion of the fork 31 used to pick up the transported object can pass through the penetration portion G in the vertical direction. For example, the fork 31 can be lowered until the lower surface of the fork portion 312 is flush with the lower surface of the base plate 111b. Furthermore, after the fork 31 is lowered until the lower surface of the fork portion 312 is flush with the lower surface of the base plate 111b, the fork portion 312 can be moved further forward (in the X direction X1) and / or extended. Alternatively, the fork 31 can be lowered below the lower surface of the base plate 111b. The penetration portion G of multiple notches 12 can have the same length in the picking direction (X direction).

[0077] In this embodiment, the notch portion 12 includes a first notch portion 121 and a second notch portion 122 located closer to the other side Y2 in the Y direction than the first notch portion 121. Figure 5 As shown. The first notch 121 and the second notch 122 are spaced apart in the Y direction. The first notch 121 and the second notch 122 are arranged on either side of the second chassis portion 102 in the Y direction, sandwiching the second chassis portion 102 therebetween. The first notch 121 is located between the first chassis portion 101 and the second chassis portion 102 in the Y direction. The second notch 122 is located between the second chassis portion 102 and the third chassis portion 103 in the Y direction.

[0078] At least a portion of the chassis 10 is located in front (one side X1 in the X direction) of the gantry 21. Here, "located in front of the gantry" means basically located in front of it in any state, and the so-called front side here is right in front of the gantry along the picking direction.

[0079] In addition, the chassis 10 also includes a loading portion for carrying the transported object. In this embodiment, at least a portion of the upper surface of the chassis body 11 constitutes the loading portion. Figure 1 and Figure 5 As shown, the portion of the first chassis section 101, the second chassis section 102, and the third chassis section 103 that is located forward of the gantry 21 (in the X-direction, one direction, X1) serves as the loading portion. At least a portion of the loading portion of the second chassis section 102 is located forward of the gantry 21 (in the X-direction, one direction, X1). Alternatively, the first chassis section 101 and the second chassis section 102 may be used to load objects, and the second chassis section 102 may not be used to load objects.

[0080] (Gate frame assembly)

[0081] The gantry assembly 20 includes a gantry 21 and a gantry moving portion 22. The gantry 21 is supported on the chassis 10 so as to be reciprocally movable in the pickup direction (X direction).

[0082] The gantry 21 includes a first gantry 211 and a second gantry 212. The second gantry 212 is supported on the first gantry 211 so as to be raised and lowered in the vertical direction. For example, the second gantry 212 is supported on the first gantry 211 so as to be raised and lowered by a cylinder 41. At least a portion of the second gantry 212 is located inside the first gantry 211. The connection and assembly relationship between the second gantry 212 and the first gantry 211 is the same as that of existing gantry structures and will not be described in detail here. Alternatively, the second gantry 212 may be supported on the first gantry 211 so as to be raised and lowered by an actuator other than a cylinder.

[0083] In addition, the gantry 21 further includes covers 213, 213 covering portions of the first gantry 211 on both sides in the Y direction. Figure 3 shown.

[0084] The gantry 21 is capable of moving in the picking direction (X direction) relative to the chassis 10. The initial position of the gantry 21 is the rearmost position (X2 on the other side of the X direction) in the gantry's moving stroke, that is, the rearmost end of the moving stroke. In this embodiment, the range of movement of the gantry 21 in the picking direction (X direction) does not exceed the front and rear ends of the chassis 10 in the picking direction (X direction end X1 on one side of the X direction and X2 on the other side of the X direction). In this way, in the picking direction, the gantry 21 partially moves within the range of the chassis 10, and compared with the case where the gantry 21 moves to a position further forward than the chassis 10 (X1 on one side of the X direction), for example, the counterweight used to balance the weight of the forked transport object on the forklift 100 can be reduced. In addition, the partial movement of the gantry 21 within the range of the chassis 10 can be achieved by electronic control.

[0085] The width of the chassis 10 in the pickup direction (X direction) is defined as L. Preferably, the ratio of the travel of the gantry 21 in the pickup direction (X direction) to the width L of the chassis 10 in the pickup direction is 0.7 or less. This reduces or eliminates the need for counterweight. Here, "the width of the chassis in the pickup direction" refers to the distance between the front and rear ends of the chassis 10 in the pickup direction.

[0086] In this embodiment, the gantry 21 is supported on the chassis body 11 of the chassis 10 so as to be movable back and forth in the picking direction (X direction) via the gantry moving part 22. In other words, the gantry moving part 22 supports the gantry 21 on the chassis 10 so as to be movable back and forth in the picking direction (X direction). The gantry moving part 22 has a free end that is further forward (one side X1 in the X direction) than the gantry. The range of movement of the gantry moving part 22 including the free end in the picking direction (X direction) does not exceed the front and rear ends of the chassis 10 in the picking direction. Thus, even when the chassis 10 and the transport object to be forked are relatively close in the X direction, the forking of the transport object placed on the ground can be achieved, which is particularly suitable for picking up goods in narrow alleys.

[0087] In this embodiment, the gantry moving portion 22 moves together with the gantry 21. The gantry moving portion 22 is connected to the gantry 21 and supports the gantry 21. For example, the gantry moving portion 22 supports the gantry 21 at the rear end (the other end X2 in the X direction).

[0088] like Figure 8 and Figure 9As shown, the gantry moving part 22 includes a pair of support parts 221 and 222. The front (one side X1 in the X direction) end of the support parts 221 and 222 serves as the above-mentioned free end. The support parts 221 and 222 do not overlap with the fork 31 in the up and down directions. In other words, the projections of the support parts 221 and 222 and the fork 31 do not overlap. The lengths of the support parts 221 and 222 in the picking direction (X direction) can be the same as each other. In addition, the length of the support part 221 in the picking direction (X direction) is shorter than the length of the first notch part 121 in the picking direction. The length of the support part 222 in the picking direction (X direction) is shorter than the length of the second notch part 122 in the picking direction.

[0089] In this embodiment, the support portions 221 and 222 are connected to the gantry 21. More specifically, the support portions 221 and 222 have a shape extending in the X-direction. The support portions 221 and 222 are spaced apart in the Y-direction. The support portion 221 is positioned closer to one side Y1 in the Y-direction than the support portion 222. The support portion 221 includes a first plate 221a extending in the X-direction and having a plate-like shape with its thickness extending in the vertical direction; and a second plate 221b bent relative to the first plate 221a and extending in the X-direction and having a plate-like shape with its thickness extending in the Y-direction. The support portion 222 includes a first plate 222a extending in the X-direction and having a plate-like shape with its thickness extending in the vertical direction; and a second plate 222b bent relative to the first plate 222a and extending in the X-direction and having a plate-like shape with its thickness extending in the Y-direction. The first plates 221a and 222a are each configured so that their width (width in the Y-direction) narrows as they move forward (toward the X-direction).

[0090] The gantry moving portion 22 also includes a connecting plate 223 connecting the rear ends of the first plates 221a and 222a of the pair of support portions 221 and 222; extensions 221c and 222c extending upward from the rear ends of the first plates 221a and 222a, respectively; and third plates 221d and 222d connecting the first plates 221a and 222a to the second plates 221b and 222b, respectively. The extension 221c is positioned closer to the gantry 21 on one side (Y1) in the Y direction. The extension 222c is positioned closer to the gantry 21 on the other side (Y2) in the Y direction. The connecting plate 223 has an upward-facing surface. The pair of support portions 221 and 222, the connecting plate 223, the extensions 221c and 222c, and the third plates 221d and 222d form a storage support portion S for storing and supporting the gantry 21. For example, the two extensions 221c, 222c and the third plates 221d, 222d can be fastened to the first gantry 211 of the gantry 21 using fasteners such as bolts. Furthermore, the gantry moving portion 22 can be a single component. Alternatively, the gantry moving portion 22 can be integrally formed with the first gantry 211 of the gantry 21. Specifically, the gantry moving portion 22 includes a support portion that is connected to or integrally formed with the gantry 21.

[0091] In addition, the mast assembly 20 further includes a connecting frame 23 connecting the rear ends of the two extensions 221c and 222c. The connecting frame 23 covers a portion of the mast 21 from the rear.

[0092] The support portion 221 can be in sliding or rolling contact with the chassis body 11 of the chassis 10, thereby being movably supported on the chassis 10 in the pickup direction (X direction). However, the present invention is not limited thereto. The support portion 221 can also be movably supported on the chassis 10 in the pickup direction (X direction) by means other than sliding or rolling contact. In this embodiment, the support portion 221 is in rolling contact with the chassis body 11.

[0093] As mentioned above, the chassis 10 is provided with a first notch 121 and a second notch 122 for the forking portion of the fork 31 to pass through. Figure 5 As shown, the first notch 121 has a pair of side walls 1211 and 1212 that oppose each other in the Y direction. Side wall 1211 faces the Y2 side, the other direction in the Y direction. Side wall 1212 faces the Y1 side, the one direction in the Y direction. Side wall 1211 is also part of the first chassis portion 101. Side wall 1212 is also part of the second chassis portion 102. A track 51 is provided on side wall 1211. Track 51 extends in the X direction. The second notch 122 has a pair of side walls 1221 and 1222 that oppose each other in the Y direction. Side wall 1221 faces the Y1 side, the one direction in the Y direction. Side wall 1222 faces the Y2 side, the other direction in the Y direction. Side wall 1221 is also part of the third chassis portion 103. Side wall 1222 is also part of the second chassis portion 102. A track 52 is provided on side wall 1221. Track 52 extends in the X direction. In addition, the side wall 1212 may be provided with a track 51, and the side wall 1222 may be provided with a track 52. By providing the track on the side walls 1211 and 1221 closer to the outside of the chassis 10 in the first notch 121 and the second notch 122, the door frame 21 can be better supported.

[0094] like Figure 7 and Figure 9 As shown, the support portions 221 and 222 are respectively equipped with rollers 61 and supported on the rails 51 and 52 via the rollers 61. Thus, the support portions 221 and 222 are respectively supported on the side walls 1211 and 1221. Because the range of movement of the gantry moving portion 22, including the free end, in the picking direction (X direction) does not exceed the front and rear ends of the chassis 10 in the picking direction, the movement stroke of the gantry 21, which moves together with the gantry moving portion 22, is shorter than the length of the notch in the picking direction.

[0095] Each of the support parts 221 and 222 includes a front end (one side of the X direction X1) and a rear end (the other side of the X direction X2) along the picking direction (X direction). The roller 61 is rotatably supported on the second plates 221b and 222b of the support parts 221 and 222. There are multiple rollers 61. The multiple rollers 61 include: a first roller 611 installed at the front end near the support part 222 (221); and a second roller 612 ( Figure 9 (In the figure, only the first and second rollers mounted on the support portion 222 are shown.) "Close to the front end of the support portion" refers to a position further forward than the center of the support portion (one side, X1, in the X-direction), and the support effect improves as the distance from the front end of the support portion increases. "Close to the rear end of the support portion" refers to a position further rearward than the center of the support portion (the other side, X2, in the X-direction), and the support effect improves as the distance from the rear end of the support portion increases. In addition, one or more additional rollers 61 may be provided between the first roller 611 and the second roller 612.

[0096] As described above, in the picking direction, the gantry 21 partially moves within the range of the chassis 10, and the range of movement of the gantry moving portion 22 including the free end in the picking direction (X direction) does not exceed the front and rear ends of the chassis 10 in the picking direction. The dimension of the support portions 221 and 222 in the picking direction (X direction) is set to L1, and the dimension L1 of the support portions 221 and 222 in the picking direction is shorter than the width L of the chassis 10 in the picking direction. Preferably, the ratio (L1 / L) of the dimension L1 of the support portions 221 and 222 in the picking direction (X direction) to the width L of the chassis 10 in the picking direction is 0.35 to 0.75. In this way, the gantry 21 can be partially moved within the range of the chassis 10 while further stably supporting the gantry. More preferably, the ratio (L1 / L) of the dimension L1 of the support portions 221 and 222 in the picking direction (X direction) to the width L of the chassis 10 in the picking direction is 0.40 to 0.70.

[0097] (Gantry drive mechanism)

[0098] The gantry driving mechanism 70 is used to move the gantry 21 in the pickup direction. The gantry driving mechanism 70 includes a driving source (not shown) for moving the gantry in the pickup direction.

[0099] In this embodiment, the gantry drive mechanism 70 includes: a gear 71 rotatably supported on the gantry assembly 20; a rack 72 meshing with the gear 71 and mounted on the chassis 10; and a motor (not shown) serving as a driving source for rotating the gear 71. Figure 12As shown, the gear 71 is mounted on the gantry moving portion 22. The rack 72 is mounted on the chassis body 11. The connection and assembly relationship between the gear 71 and the gantry assembly 20, and the connection and assembly relationship between the rack 72 and the chassis 10 are the same as those of the existing gantry drive mechanism, so they will not be repeated here. In addition, the gear 71 can also be mounted on the chassis 10, and the rack 72 can be mounted on the gantry assembly 20. That is, the gantry drive mechanism 70 includes a gear 71 that is rotatably supported on one of the gantry assembly 20 and the chassis 10; and a rack that is meshed with the gear 71 and mounted on the other of the gantry assembly 20 and the chassis 10.

[0100] By adopting the rack and pinion transmission, it is easy to reduce the size of the chassis 10 in the picking direction (X direction) and lighten the weight of the gantry drive mechanism compared to the case of using, for example, an oil cylinder as an actuator.

[0101] The unmanned forklift 100 further includes a mast control unit (not shown, equivalent to the "control unit" in this disclosure). The mast control unit controls the operation of the driving source.

[0102] (Limiting mechanism)

[0103] Furthermore, the unmanned forklift 100 may include a limiting mechanism 80 provided on at least one of the mast assembly 20 and the chassis 10. The limiting mechanism 80 is configured to limit the mast moving portion 22 from moving beyond the front end (one X direction X1) of the chassis body 11 of the chassis 10.

[0104] For example, the limiting mechanism includes a first portion and a second portion, the first portion being provided on the mast assembly 20 and the second portion being provided on the chassis 10. Before the mast moving portion 22 moves beyond the front end of the chassis 10, the first portion is engaged with the second portion. This prevents undesirable situations caused by the mast moving portion 22 accidentally moving beyond the front end of the chassis 10.

[0105] In this embodiment, as the second part, limit blocks 81 and 82 are provided on the chassis 10 in front of the gantry moving part 22 (one side X1 in the X direction). Figure 5 More specifically, the stopper 81 is fixed to the track 51. The stopper 82 is fixed to the track 52. In addition, the front end portion of the gantry moving portion 22 becomes the first portion. Alternatively, only one stopper may be provided.

[0106] (Rear end limit mechanism)

[0107] The unmanned forklift 100 may further include a rear end stopper mechanism 90 disposed on at least one of the mast assembly 20 and the chassis 10. The rear end stopper mechanism 90 is configured to limit rearward movement of the mast movable portion 22 beyond a predetermined position (in the other X-direction X2). The predetermined position may be the position of the mast movable portion 22 when the mast 21 is in the initial position, or a position further rearward (in the other X-direction X2) than this position.

[0108] In this embodiment, a first detection device is provided between the gantry assembly 20 and the chassis 10. The rear end limit mechanism 90 includes a first detection device and a gantry control unit. The first detection device includes: a first sensor 91 provided on the chassis 10; and a trigger plate 92 provided on the gantry assembly 20 and moving together with the gantry 21 and the gantry moving unit 22. The first sensor 91 can be an inductive proximity switch sensor. The trigger plate 92 can be a metal sheet. Figure 11 and Figure 13 As shown, the first sensor 91 is fixed to the rib 112b of the chassis 10 via a bracket and fasteners such as bolts. Figure 14 As shown, the trigger piece 92 is fixed to the gantry moving part 22 via fasteners such as bolts. The trigger piece 92 and the first sensor 91 are opposite to each other in the picking direction (X direction). As the gantry moving part 22 moves in the picking direction relative to the chassis 10, the distance between the trigger piece 92 and the first sensor 91 changes.

[0109] When the trigger piece 92 moves to a distance less than the specified distance from the first sensor 91 and triggers the first sensor 91, the first sensor 91 sends a first signal to the gantry control unit, and the gantry control unit that receives the first signal stops the above-mentioned driving source.

[0110] (Fork assembly)

[0111] The fork assembly 30 is supported on the gantry 21 so as to be movable up and down. Thus, it is possible to pick up and place goods at different heights. In more detail, the fork assembly 30 is supported on the second gantry 212 so as to be movable up and down. Figure 8 As shown, the fork assembly 30 includes a fork 31 and a base 32 .

[0112] The base 32 can be supported on the second gantry 212 of the gantry 21 so as to be lifted and lowered in the up and down directions. The fork 31 is supported on the base 32 by hooking, fastening, etc., and moves up and down together with the base 32. In this embodiment, the unmanned forklift 100 includes a pulley 24 and a flexible cable 25. The pulley 24 is installed near the top of the second gantry 212. The flexible cable 25 can be a sling, a synchronous belt or a chain. One end of the flexible cable 25 is fixed to the base 32, and the other end extends upward, passes around the pulley 24, and then extends downward and is fixed to the first gantry 211. When the second gantry 212 is pushed to move by the oil cylinder 41, the base 32 is pulled up by the flexible cable 25. The rising height of the base 32 (fork assembly 30) is twice the rising height of the second gantry 212.

[0113] In this embodiment, two forks 31 are provided. More specifically, two forks 31 are arranged in the Y direction. The two forks 31 can be formed into the same structure. When viewed from the picking direction, the forks 31 are located in front of the gantry 21 (one side X1 in the X direction). For example, the chassis 10 moves in a state where the gantry 21 is in the initial position and the forks 31 (the forking portion 312) are retracted. Figure 4 As shown, when the mast 21 is located at the initial position and the fork 31 is retracted, the projection of the fork 31 is located within the range of the chassis 10, thereby preventing the fork from interfering with surrounding objects when the chassis 10 is moving.

[0114] Furthermore, when the mast 21 is in its initial position and the fork 31 (the fork portion 312 thereof) is not retracted, the projection of the fork 31 may be within or beyond the chassis 10. For example, in one embodiment, the fork 31 may function as a single-deep fork. In this case, when the mast 21 is at the rearmost end of its travel, the projection of the fork 31 is within the chassis 10 even if the fork portion 312 is not retracted. In another embodiment, the fork 31 may function as a multi-deep fork for carrying double or more cargo. In this case, when the mast 21 is at the rearmost end of its travel and the fork portion 312 is not retracted, the projection of the fork 31 is beyond the chassis 10. However, when the mast 21 is at the rearmost end of its travel and the fork portion 312 is retracted, the projection of the fork 31 is within the chassis 10.

[0115] In this embodiment, the fork is a two-stage telescopic structure. Figure 10 and Figure 11 As shown, the fork 31 has a main body 311 and a forking portion 312. The main body 311 has an "L" shape when viewed from the side. Figure 2 As shown, the main body portion 311 may be divided into a third portion 311 a extending along the X direction and a fourth portion 311 b extending upward from a rear end of the third portion 311 a .

[0116] The fork portion 312 extends in the X-direction. The fork portion 312 is the portion that contacts the object being transported. For example, the upper surface of the fork portion 312 contacts the object being transported. For example, the fork portion 312 can be used to pick up a pallet loaded with goods, as well as an unloaded pallet.

[0117] The fork portion 312 slides and retracts relative to the main body 311 in the picking direction (X direction) to fork and transport the object. For example, the fork 31 is driven by hydraulic oil. The main body 311 is provided with a cylinder. For example, the third part 311a can be used as a cylinder. The fork portion 312 includes a fork portion housing 312a. When the fork is retracted, the fork portion housing 312a is sleeved on the outside of the main body 311. The fork 31 also includes a piston rod (not shown) that moves telescopically relative to the above-mentioned cylinder. The fork portion 312 is driven by the piston rod to move in the picking direction. The above-mentioned piston rod extends along the X direction, and at least a part of it extends into the fork portion housing 312a.

[0118] Preferably, when the fork 31 is lowered to its lowest position (the position closest to the other Z-direction Z2), the lower surface SF1 of the forking portion 312 (the surface in the other Z-direction Z2) is positioned lower (in the other Z-direction Z2) than the upper surface SF2 (the surface in the one Z-direction Z1) of the support portions 221 and 222. Thus, when the fork 31 is lowered to its lowest position, the height of the fork 31 can be lowered to a level lower than the upper surface SF2 of the support portions 221 and 222, enabling a lower height for picking and placing cargo.

[0119] In one example, the unmanned forklift 100 of the present disclosure is capable of picking up a Sichuan-shaped pallet or a Tian-shaped pallet with a pallet insertion hole height of 100 mm or less.

[0120] Furthermore, the fork 31 is provided with an upwardly protruding stopper 313 at the rear end of the forking portion 312 , thereby preventing the transported object picked up by the forking portion 312 from contacting the main body 311 and hindering the extension and retraction of the forking portion 312 .

[0121] In addition, a second sensor 14 is installed at the front end of the chassis 10. Figure 2 As shown in the figure, the second sensor 14 identifies the outline of the pallet placed on the ground as the transport target. Based on the detection results of the second sensor 14, the forks can be adjusted to an appropriate height to facilitate picking up the pallet. The second sensor can be a radar. By installing the second sensor 14 at the front end of the chassis 10, there is no need to install a height adjustment sensor at the front end of the fork picking portion 312 of the fork 31 for low-level pickup. This makes it easier to reduce the vertical thickness of the fork 31.

[0122] Furthermore, the driverless forklift 100 may include a sensor for recognizing the outline of the pallet at a position away from the ground.

[0123] Hereinafter, an example of a transportation method using the automated forklift 100 will be described.

[0124] The unmanned forklift 100 disclosed herein can pick up goods from high positions such as shelves far from the ground, place goods on high positions such as shelves far from the ground, pick up goods from low positions close to the ground (including the ground), and place goods on low positions close to the ground.

[0125] For example, in the case of picking up goods, the method of transporting goods using the unmanned forklift 100 includes:

[0126] The vehicle body position adjustment step is to move the chassis 10 to a position where the forks can center and pick up the transported object (e.g., a pallet);

[0127] In the picking step, the transport object picked up by the fork 31 is transported to the placement portion on the chassis 10 .

[0128] In addition, during the vehicle body position adjustment step, the vehicle body position can be adjusted by identifying the pallet outline distance through sensors such as radar.

[0129] The above-mentioned picking-up step may include: after the fork picking portion 312 that has picked up the transported object begins to retract, the door frame 21 moves to the initial position, or,

[0130] The picking step may include: simultaneously with the fork picking portion 312 that has picked up the transported object starting to retract, the door frame 21 starting to move toward the initial position, thereby shortening the picking time.

[0131] <First Modification>

[0132] In the first embodiment described above, the limiting mechanism 80 is constructed to have a mechanical limiting block. However, it is not limited to this, and other structures can also be used to limit the movement of the front end of the chassis body 11 of the chassis 10 from the gantry moving part 22. The unmanned forklift of the second variant has an electronic limiting mechanism that is different from the limiting mechanism 80 of the first embodiment, and other than this, it has the same structure as the first embodiment. In the following, the differences from the first embodiment are mainly described, and repeated descriptions of the components that are the same as the first embodiment are omitted. Unless there is a contrary description in the following content or it conflicts with other technical features, the features described in the first embodiment are also applicable to this variant and will not be described in detail here.

[0133] In this modified example, an electronic limit mechanism (not shown) is provided on at least one of the mast assembly 20 and the chassis 10 , and is configured to limit the mast moving portion 22 from moving beyond the front end of the chassis 10 .

[0134] The electronic limit mechanism includes a second detection device (equivalent to the "detection device" in this disclosure) that detects information related to the travel distance of the gantry moving unit. For example, the second detection device transmits a signal related to the detected information related to the travel distance of the gantry moving unit to the gantry control unit. Based on the detection results of the detection device, the gantry control unit controls the operation of the drive source of the gantry drive mechanism 70 to limit the movement of the gantry moving unit 22 beyond the front end of the chassis 10.

[0135] The second detection device can be a proximity switch. For example, the second detection device comprises a third sensor mounted on the chassis 10 and a second trigger plate mounted on the mast moving portion 22. When the second trigger plate moves to a distance less than a specified distance from the third sensor, triggering the sensor, the third sensor sends a second signal to the mast control unit. Upon receiving the second signal, the mast control unit stops the drive source. The third sensor is an inductive proximity switch. The second trigger plate is a metal plate.

[0136] Alternatively, the second detection device may employ a photoelectric sensor. For example, the second detection device may include a photoelectric sensor mounted on the chassis 10. When the mast 21 moves to the extreme end of its travel or further forward, the mast moving unit 22 blocks the light emitted by the photoelectric sensor. At this point, the photoelectric sensor transmits a third signal to the mast control unit, which, upon receiving the third signal, deactivates the drive source.

[0137] Furthermore, the second detection device may be an encoder that detects the rotation of the gear 71. Based on the detection result of the encoder, the movement distance of the door moving part 22 can be calculated.

[0138] <Second Modification>

[0139] In the first embodiment described above, the support portions 221 and 222 are supported on the rails 51 and 52 via rollers 61. In this variation, the chassis 10 does not include the rails 51 and 52. The support portions 221 and 222 have lower rollers at their bottoms that contact the upper surface of the bottom plate 111b from above. The portion of the bottom plate 111b that contacts the lower rollers of the support portions 221 and 222 is located, for example, on the Y1 side of the through portion G in the Y direction or on the Y2 side of the through portion G in the Y direction. Otherwise, this variation has the same structure as the first embodiment.

[0140] The present disclosure is exemplarily described above with reference to the accompanying drawings. It is obvious that the specific implementation of the present disclosure is not limited to the above embodiments and modifications.

[0141] For example, the mast drive mechanism may include any of a sprocket chain transmission, a synchronous belt transmission, an electric cylinder, or a hydraulic cylinder, in place of a rack and pinion transmission. For example, the mast drive mechanism may include: a sprocket rotatably supported on one of the mast assembly and the chassis; a chain meshing with the sprocket and mounted on the other of the mast assembly and the chassis; and a motor that drives the sprocket for rotation. In this case, the second detection device may be an encoder that detects the rotation of the sprocket.

[0142] For example, the support portions 221 and 222 do not necessarily have to have a shape extending in the X direction, and at least a portion thereof may be curved or inclined with respect to the X direction.

[0143] For example, three or more forks 31 may be provided. In this case, it is preferable to provide three or more notches in the chassis 10 corresponding to the three or more forks.

[0144] For example, the support portion of the gantry moving portion may be supported by a portion of the chassis body other than the side wall and the bottom plate of the notch portion.

[0145] For example, the support portion may be supported on the chassis by a slide rail and slider structure, or a recyclable ball bearing may be provided between the slide rail and the slider, and a wear-resistant copper plate may be provided between the slide rail and the slider.

[0146] For example, the limiting mechanism can also limit the door frame.

[0147] For example, the gantry can also be supported on the chassis in a non-contact manner.

[0148] For example, the unmanned forklift 100 can be configured to travel in multiple directions. The chassis can also be configured as an omnidirectional motion chassis.

[0149] The above description specifically describes the specific embodiments of the present disclosure in conjunction with the accompanying drawings. However, it should be understood that the above description does not limit the present disclosure in any way, and the technical features of the various embodiments can be combined in any manner to form new embodiments. In addition, after understanding the above specific embodiments, those skilled in the art may make various other modifications and changes to the present disclosure as needed. These modifications and changes do not deviate from the essence of the present disclosure.

Claims

1. An unmanned forklift, characterized in that: include: A chassis for walking, wherein the chassis can walk in a direction perpendicular to the picking direction; A gantry assembly, the gantry assembly comprising a gantry supported on the chassis so as to be movable back and forth in a picking direction; as well as a fork assembly, the fork assembly being supported on the mast so as to be movable up and down and having a fork, wherein the fork is located in front of the mast when viewed in the picking direction, and at least a portion of the chassis is also located in front of the mast, The fork has: the main body; and The fork portion can slide and retract relative to the main body.

2. The unmanned forklift according to claim 1, characterized in that: The gantry assembly further includes a gantry moving portion, the gantry being supported on the chassis so as to be movable back and forth in the picking direction via the gantry moving portion, the gantry moving portion having a free end further forward than the gantry, The range of movement of the gantry and the gantry moving part including the free end in the picking direction does not exceed the front and rear ends of the chassis in the picking direction.

3. The unmanned forklift according to claim 2, characterized in that: The gantry moving part moves together with the gantry, The gantry moving part includes a support part connected to or integrally formed with the gantry, and the support part is in sliding contact or rolling contact with the chassis.

4. The unmanned forklift according to claim 3, characterized in that: The support portion and the fork do not overlap in the vertical direction.

5. The unmanned forklift according to claim 4, characterized in that: When the fork is lowered to the lowest position, the lower surface of the forking portion is lower than the upper surface of the supporting portion.

6. The unmanned forklift according to claim 3, characterized in that: The chassis is provided with a notch for the forking portion of the fork to pass through. The side wall of the notch is provided with a track. The support portion is equipped with rollers and supported on the track via the rollers. The moving stroke of the gantry is shorter than the length of the notch in the picking direction.

7. The unmanned forklift according to claim 6, characterized in that: The support portion includes a front end and a rear end along the picking direction, The roller is provided with a plurality of The plurality of rollers include: a first roller installed near the front end; and a second roller installed near the rear end.

8. The unmanned forklift according to claim 3, characterized in that: The chassis has a bottom plate, The supporting portion is supported on the bottom plate so as to be movably along the picking direction.

9. The unmanned forklift according to claim 3, characterized in that: A ratio of a dimension of the support portion in the picking direction to a width of the chassis in the picking direction is 0.35 to 0.

75.

10. The unmanned forklift according to claim 9, characterized in that: A ratio of a dimension of the support portion in the picking direction to a width of the chassis in the picking direction is 0.40 to 0.

70.

11. The unmanned forklift according to any one of claims 2 to 10, characterized in that: The invention comprises a limiting mechanism provided on at least one of the gantry assembly and the chassis, wherein the limiting mechanism is configured to limit the movement of the gantry moving part beyond the front end of the chassis.

12. The unmanned forklift according to claim 11, characterized in that: The limiting mechanism includes a first part and a second part, the first part is arranged on the door frame assembly, and the second part is arranged on the chassis. Before the gantry moving portion moves beyond the front end of the chassis, the first part is locked to the second part.

13. The unmanned forklift according to claim 12, characterized in that: The second part is a limit block provided on the chassis in front of the gantry moving part. The front end portion of the gantry moving portion serves as the first portion.

14. The unmanned forklift according to claim 11, characterized in that: comprising a driving mechanism, wherein the driving mechanism moves the gantry in the picking direction, The limiting mechanism includes: a detection device for detecting information related to a moving distance of the gantry moving portion; and A control unit controls the action of the driving mechanism based on the detection result of the detection device to limit the movement of the gantry moving unit beyond the front end of the chassis.

15. The unmanned forklift according to claim 14, characterized in that: The detection device is a proximity switch or a photoelectric sensor.

16. The unmanned forklift according to claim 14, characterized in that: The driving mechanism includes: a gear or sprocket rotatably supported on one side of the gantry assembly and the chassis; a rack or chain meshing with the gear or sprocket and installed on the other side of the gantry assembly and the chassis; and a motor driving the gear or sprocket to rotate, and the detection device is an encoder for detecting the rotation of the gear or sprocket.

17. The unmanned forklift according to any one of claims 2 to 10, characterized in that: It includes a rear end limiting mechanism provided on at least one of the mast assembly and the chassis, and the rear end limiting mechanism is configured to limit the mast moving part from moving backward beyond a specified position.

18. The unmanned forklift according to claim 17, characterized in that: comprising a driving mechanism having a driving source for moving the gantry in the picking direction, The rear end limiting mechanism includes a control unit and a first detection device, The first detection device is provided between the door frame assembly and the chassis, The first detection device includes: a first sensor provided on the chassis; and a trigger piece provided on the gantry assembly and moving together with the gantry and the gantry moving part. When the trigger piece moves to a distance less than a predetermined distance from the first sensor and triggers the first sensor, the first sensor sends a first signal to the control unit. The control unit, upon receiving the first signal, stops the driving source.

19. The unmanned forklift according to claim 1, characterized in that: The ratio of the movement stroke of the gantry in the picking direction to the width of the chassis in the picking direction is less than 0.

7.

20. The unmanned forklift according to claim 1, characterized in that: The fork is provided with a plurality of The chassis is provided with a plurality of notches corresponding to the plurality of forks. Each of the plurality of notches opens forward in the picking direction and penetrates at least at a position corresponding to the fork in the up-down direction so as to allow the forking portion of the corresponding fork to pass through.

21. The unmanned forklift according to claim 20, characterized in that: A second sensor is mounted on the front end of the chassis, and the second sensor recognizes the outline of a pallet placed on the ground as a transport object.

22. The unmanned forklift according to claim 20, characterized in that: Two forks are arranged in a direction perpendicular to the picking direction, and two notches are provided corresponding to the two forks.

23. The unmanned forklift according to claim 1, characterized in that: When the door frame is located at the rearmost end of the moving stroke and the forking portion is retracted, the projection of the fork is located within the range of the chassis.

24. The unmanned forklift according to claim 1, characterized in that: comprising a driving mechanism, wherein the driving mechanism moves the gantry in the picking direction, The driving mechanism includes: a gear rotatably supported on one of the gantry assembly and the chassis; a rack meshing with the gear and mounted on the other of the gantry assembly and the chassis; and a motor driving the gear to rotate, or The driving mechanism includes a sprocket chain transmission mechanism, or The driving mechanism includes a synchronous belt transmission mechanism, or The driving mechanism includes an electric cylinder, or The driving mechanism includes a hydraulic cylinder.

25. The unmanned forklift according to claim 1, characterized in that: The chassis includes a loading portion for loading a transported object, and at least a portion of the loading portion is located at a front side of the gantry.

26. The unmanned forklift according to claim 1, characterized in that: A blocking bar protruding upward is provided at the rear end of the forking portion.

27. The unmanned forklift according to claim 1, characterized in that: The gantry comprises: a first gantry; and a second gantry supported on the first gantry so as to be able to be raised and lowered in the vertical direction. The fork assembly is supported on the second mast so as to be movably supported up and down.

28. A method for transporting an object using the unmanned forklift according to any one of claims 1 to 27, characterized in that: The method comprises the following steps: carrying the transported object taken by the fork to the loading portion on the chassis; The picking-up step includes: after the forking portion of the fork that has picked up the transported object begins to retract, moving the mast to the rear end of the moving stroke, or, The picking-up step includes: simultaneously causing the forking portion of the fork that has picked up the transported object to begin to retract, causing the mast to begin to move toward the rearmost end of its travel.

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