Material handling vehicles

Abstract

To provide a cargo handling vehicle facilitating maintenance work of an obstacle detection sensor while setting a lower part of a driving cab as a detection target area of the obstacle detection sensor during cargo handling work.SOLUTION: A cargo handling vehicle includes a vehicle body 11 equipped with driving wheels, a pair of right and left legs 14 extending from one side of the vehicle body 11 and having wheels 15 on its tip, a pair of right and left outer masts 19 arranged on the legs 14 sides of the vehicle body 11, a driving cab 18 capable of being raised / lowered relative to the pair of right and left outer masts 19, a cargo handling tool provided in the driving cab 18, an obstacle detection sensor 47 detecting an obstacle below the cargo handling tool and the driving cab 18, a warning device issuing a warning, and a controller controlling the warning device to emit a warning when the obstacle detection sensor 47 detects an obstacle. The obstacle detection sensor 47 is installed outside a base part of at least one outer mast 19 among the pair of right and left outer masts 19. The detection target area where the obstacle can be detected by the obstacle detection sensor 47 includes a lower part of the driving cab 18.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This invention relates to a cargo handling vehicle.

Background Art

[0002] As a prior art of a cargo handling vehicle, for example, an automated guided forklift disclosed in Patent Document 1 is known. An obstacle detection device is provided at the front lower end of the automated guided forklift disclosed in Patent Document 1. The obstacle detection device has a planar detection area having a vehicle width (or a width slightly wider than the vehicle width) and extending forward by a predetermined distance at a height within a predetermined range from the floor surface. The obstacle detection device is provided at the center in the vehicle width direction of a pair of left and right mast.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As with the autonomous forklift disclosed in Patent Document 1, in order to detect obstacles in front of the vehicle, it is preferable to install obstacle detection sensors at the center of the left and right masts in the vehicle width direction to ensure an equal detection range on both sides. However, due to space constraints, it may not be possible to install obstacle detection sensors at the center of the left and right masts in the vehicle width direction. In addition, in picking forklifts where the driver's cab rises and falls relative to the mast, it is desirable to detect the presence or absence of people or obstacles below the driver's cab during cargo handling operations. Conventionally, there are picking forklifts equipped with a warning device that emits a warning sound when the driver's cab is lowered, but since the warning sound is emitted regardless of the presence or absence of people or obstacles, there is a risk that the operator will become accustomed to the warning sound. Furthermore, when obstacle detection sensors are installed at the center of the left and right masts in the vehicle width direction on a picking forklift, it is necessary to raise the driver's cab and have an operator enter below the driver's cab in order to perform maintenance and inspection of the obstacle detection sensors.

[0005] This invention has been made in view of the above-mentioned problems, and the object of this invention is to provide a cargo handling vehicle in which the area below the driver's cab is the detection area for the obstacle detection sensor during cargo handling operations, while also facilitating maintenance of the obstacle detection sensor. [Means for solving the problem]

[0006] To solve the above problems, the present invention provides a vehicle body equipped with drive wheels, a pair of left and right legs extending from one side of the vehicle body to the other, each having a wheel at the other end, a pair of left and right outer masts positioned on the leg side of the vehicle body, and a driver's cab that can be raised and lowered relative to the pair of left and right outer masts. ,before A cargo handling vehicle having an obstacle detection sensor for detecting obstacles below the driver's cab, a warning device for issuing a warning, and a controller for controlling the warning device to issue a warning when the obstacle detection sensor detects an obstacle, wherein the obstacle detection sensor is installed on the outside of the base of at least one of the left and right outer masts, and the detection target area in which the obstacle detection sensor detects an obstacle includes below the driver's cab. Furthermore, the controller causes the warning device to display an indication of the presence of an obstacle when the obstacle detection sensor detects an obstacle in the detection target area when the driver's cab is raised or stopped, and generates a warning sound in the warning device when the obstacle detection sensor detects an obstacle in the detection target area when the driver's cab is lowered. It is characterized by the following:

[0007] In this invention, the obstacle detection sensor is installed on the outside of the base of at least one of the pair of outer masts. Therefore, even if the obstacle detection sensor is installed on the outside of the base of only one outer mast, the detection area of ​​the obstacle detection sensor can be made capable of detecting obstacles in almost the entire area below the driver's cab, except for the area near the base of the other outer mast below the driver's cab. Furthermore, since the obstacle detection sensor is installed on the outside of the base of one outer mast, it is not necessary to raise the driver's cab when performing maintenance on the obstacle detection sensor. Therefore, during maintenance work, the worker can access the obstacle detection sensor without having to enter the area below the driver's cab.

[0008] Furthermore, in the above-described cargo handling vehicle, the detection target area may be configured to include, below the driver's cab, the entirety of one of the pair of left and right legs, and at least the portion of the other leg that is closer to the tip than the base. In this case, if the obstacle detection sensor is installed only on the outside of the base of one of the outer masts, the detection area of ​​the obstacle detection sensor will include the entirety of one leg and the part of the other leg that is further forward than the base, below the driver's cab. In this case, it is possible that the base of the other leg may fall outside the detection area, but it is very unlikely that an obstacle will go over the other leg and enter below the driver's cab.

[0009] Also, The present invention relates to a cargo handling vehicle comprising: a vehicle body equipped with drive wheels; a pair of left and right legs extending from one side of the vehicle body to the other, each having a wheel at the other end; a pair of left and right outer masts positioned on the leg side of the vehicle body; a driver's cab that can be raised and lowered relative to the pair of left and right outer masts; an obstacle detection sensor for detecting obstacles below the driver's cab; a warning device for issuing a warning; and a controller for controlling the warning device to issue a warning when the obstacle detection sensor detects an obstacle. The obstacle detection sensors are installed on the outside of the bases of the left and right pair of outer masts. The detection area in which the obstacle detection sensor detects an obstacle includes the area below the driver's cab, and the obstacle detection sensors, each installed on the outside of the base of the left and right pair of outer masts, are characterized in that their heights from the road surface in the detection area are different from each other. . In this invention Since obstacle detection sensors are installed on the outside of the base of one outer mast and the other outer mast, almost the entire area below the driver's cab can be used as the detection area.

[0010] Also ,left Because the detection heights of the pair of obstacle detection sensors on the right are different, overlapping of the detection target areas can be avoided, preventing false detection of obstacles due to overlapping detection target areas.

[0011] Also, The present invention relates to a cargo handling vehicle comprising: a vehicle body equipped with drive wheels; a pair of left and right legs extending from one side of the vehicle body to the other, each having a wheel at the other end; a pair of left and right outer masts positioned on the leg side of the vehicle body; a driver's cab that can be raised and lowered relative to the pair of left and right outer masts; an obstacle detection sensor for detecting obstacles below the driver's cab; a warning device for issuing a warning; and a controller for controlling the warning device to issue a warning when the obstacle detection sensor detects an obstacle, wherein the obstacle detection sensor is installed on the outside of the base of each of the left and right outer masts, and the detection target area in which the obstacle detection sensor detects an obstacle includes the area below the driver's cab. The obstacle detection sensors, each installed on the outside of the base of the pair of left and right outer masts, have the same detection height, and the detection area of ​​one obstacle detection sensor is set to one side of the center in the width direction of the vehicle body, while the detection area of ​​the other obstacle detection sensor is set to the other side of the center in the width direction of the vehicle body. Characterized by . In this invention The detection heights of the pair of obstacle detection sensors are the same. However, the detection area of ​​one obstacle detection sensor is set to one side of the vehicle's width center, and the detection area of ​​the other obstacle detection sensor is set to the other side of the vehicle's width center, so their detection areas do not overlap. Therefore, false detection of obstacles due to overlapping detection areas can be prevented. 。 [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a cargo handling vehicle in which the area below the driver's cab is the detection area for the obstacle detection sensor during cargo handling operations, while also facilitating maintenance of the obstacle detection sensor. [Brief explanation of the drawing]

[0013] [Figure 1] This is a side view of a forklift according to the first embodiment. [Figure 2] This is a perspective view of a forklift according to the first embodiment. [Figure 3] This is a schematic diagram of a forklift according to the first embodiment. [Figure 4] This is a schematic plan view showing the detection and non-detection areas of a forklift. [Figure 5] This is a schematic plan view of a forklift supporting a pallet. [Figure 6] This is a schematic plan view of a forklift according to the second embodiment. [Figure 7] This is an explanatory diagram illustrating the height difference between a pair of obstacle detection sensors on the left and right sides. [Figure 8] This is a vocabulary simplified plan view of a forklift according to a modification of the second embodiment.

Modes for Carrying out the Invention

[0014] (First Embodiment) Hereinafter, a cargo handling vehicle according to the first embodiment will be described with reference to the drawings. The cargo handling vehicle of this embodiment is an order picking type forklift. Regarding "front-rear", "left-right", and "up-down" for specifying directions, it is shown based on the state where an operator of the order picking type forklift boards the driver's cab and faces the forward side of the order picking type forklift.

[0015] As shown in FIG. 1, an order picking type forklift (hereinafter simply referred to as "forklift") 10 as a cargo handling vehicle has a vehicle body 11, and drive wheels 12 are provided at the front part of the vehicle body 11. The drive wheels 12 are front wheels and also steerable steering wheels, and are located near the center in the left-right direction of the vehicle body 11. A traveling motor 13, which is an electric motor for traveling, is mounted on the vehicle body 11, and the traveling motor 13 drives the drive wheels 12. Further, a steering device (not shown) is mounted on the vehicle body 11, and the steering device steers the drive wheels 12. A pair of left and right legs 14 extending from the front (one side) to the rear (the other side) are provided at the rear part of the vehicle body 11, and wheels 15 are provided at the tip ends of the legs 14. The wheels 15 are rotatable rear wheels and are driven wheels in this embodiment.

[0016] The forklift 10 has a mast device 16. The mast device 16 is provided at the rear part of the vehicle body 11, and includes a mast 17 and an operator's cab 18 that can move up and down with respect to the mast 17. The mast 17 is a full-free three-stage mast having an outer mast 19, a middle mast 20, and an inner mast 21. A pair of left and right middle masts 20 that can move up and down inside the outer mast 19 are provided on the pair of left and right outer masts 19. An inner mast 21 that can move up and down inside the middle mast 20 is provided on the middle mast 20.

[0017] The middle mast 20 is equipped with a chain wheel 22 on which a lift chain (not shown) is mounted. The lift chain is mounted on the chain wheel 22, and the other end of the lift chain is fixed to the lower part of the inner mast 21. Therefore, the lift chain is connected to the outer mast 19 and the inner mast 21 via the middle mast 20. The outer mast 19 is equipped with a rear lift cylinder 23 that is operated by supplying and discharging hydraulic fluid. The operation of the rear lift cylinder 23 causes the middle mast 20 to rise and fall inside the outer mast 19, and also causes the inner mast 21 to rise and fall inside the middle mast 20. The vehicle body 11 is equipped with a mast support member 24 for holding the mast 17. The mast support member 24 is a member fixed to the outer surface of the outer mast 19 and the rear surface of the vehicle body 11.

[0018] A front lift cylinder 25 is mounted on an inner lower beam (not shown) that connects a pair of left and right inner masts 21 at the bottom. The front lift cylinder 25 is a hydraulic cylinder for raising and lowering the driver's cab 18 relative to the inner mast 21. A chain wheel 26 is provided at the upper end of the piston rod of the rear lift cylinder 23. A lift chain (not shown) that connects the inner mast 21 and the driver's cab 18 is attached to the chain wheel 26. Therefore, when the piston rod of the front lift cylinder 25 rises, the driver's cab 18 rises without the inner mast 21 or middle mast 20 rising. The outer mast 19 is equipped with a lift height sensor 27 that detects whether or not the middle mast 20 is rising. The lift height sensor 27 is provided to detect the extension and retraction state of the rear lift cylinder 23, and any sensor that emits an ON signal when the middle mast 20 is raised will suffice.

[0019] Next, the driver's cab 18 will be described. As shown in Figure 2, the driver's cab 18 is a roughly rectangular platform on which an operator can sit. A pair of forks 28, which serve as cargo handling equipment, are provided at the bottom of the driver's cab 18. The forks 28 extend from the bottom of the driver's cab 18 toward the rear (other side). A pair of pillars 29 are erected at the front of the driver's cab 18. The pillars 29 support the head guard 30, which will be described later. Between the left and right pillars 29, there is a front wall 31 that extends from the driver's cab 18. The front wall 31 is about half the height of the pillars 29, and a metal protective net 32 ​​is provided above the front wall 31.

[0020] As shown in Figure 2, an instrument panel 33 is provided on the front wall 31. The instrument panel 33 is equipped with a steering wheel 34 and an accelerator lever 35, as well as a cargo handling lever 36 and a display 37. An operating pedal 38 is provided on the driver's cab 18. The steering wheel 34 is a wheel operated by the operator when changing direction while driving. The accelerator lever 35 is a lever for accelerating when the forklift 10 is moving forward or backward. The cargo handling lever 36 is a lever for raising and lowering the driver's cab 18. The accelerator lever 35 and the cargo handling lever 36 are the operating parts. Therefore, the forklift 10 of this embodiment is a cargo handling vehicle in which the operator, seated in the driver's cab 18, faces the vehicle body 11, with the front of the operator being the forward direction and the rear of the leg 14 being the reverse direction.

[0021] The display 37 includes a display unit (not shown) for displaying various information and a speaker unit (not shown) for generating warning sounds. The display unit of the display 37 can also illuminate and flash. The display 37 also generates warning sounds. The display unit and speaker unit constitute a warning device. Near the top of the front wall 31, there is a pair of left and right side gates 39 for operator protection. The side gates 39 are L-shaped gate bars that can move up and down and are fixed in a retracted position, which is an upward rotation position, and a guard position, which is a downward rotation position. Figure 1 shows the side gate 39 in the guard position, and Figure 2 shows the side gate 39 in the retracted position.

[0022] Next, the electrical configuration of the forklift 10 will be described. As shown in Figure 3, the forklift 10 has a controller 41 that controls various parts of the forklift 10. The controller 41 includes a CPU 42 and a storage unit 43 consisting of RAM and ROM, etc. The controller 41 may also include dedicated hardware, such as an application-specific integrated circuit (ASIC), that performs at least some of the various processes. The controller 41 can be configured as a circuit including one or more processors that operate according to a computer program, one or more dedicated hardware circuits such as ASICs, or a combination thereof.

[0023] The memory unit 43 stores program code or commands configured to cause the CPU 42 to execute processing. The memory unit 43 stores various programs for controlling each part of the forklift 10. The controller 41 is electrically connected to the travel motor 13 and the display 37. The controller 41 is also connected to the load handling lever sensor 44, the side gate sensor 45, and the lower alarm buzzer 46. The load handling lever sensor 44 detects the amount of upward and downward operation of the load handling lever 36 and transmits a signal to the controller 41. The side gate sensor 45 detects the retracted position and guard position of the side gate 39 and transmits a signal to the controller 41. The lower alarm buzzer 46 is a buzzer that emits an alarm below the driver's cab 18 when the obstacle detection sensor 47, which will be described next, detects an obstacle.

[0024] In this embodiment, an obstacle detection sensor 47 is provided on the outside of the base of the left outer mast 19, which is one of a pair of outer masts 19. Specifically, the obstacle detection sensor 47 is attached to the rear surface of the mast support member 24, which is the surface facing the other side, via a bracket 48. The obstacle detection sensor 47 is a sensor for detecting obstacles below the driver's cab 18 at the rear of the vehicle body 11 and below the pallet P when the forks 28 are supporting the pallet P. The obstacle detection sensor 47 is positioned at a predetermined height from the road surface.

[0025] The obstacle detection sensor 47 in this embodiment is a laser rangefinder (LRF). A laser rangefinder is a distance meter that measures distance by irradiating a detection target area where obstacles can be detected with a laser and receiving the reflected light reflected from the part where the laser hits, and can acquire information about the shape of obstacles present in the detection target area. In this embodiment, a two-dimensional laser rangefinder is used that irradiates a laser while changing the irradiation angle in the horizontal direction. By scanning the laser in the horizontal direction, the direction and distance to an object can be detected as a point cloud.

[0026] As shown in Figure 4, the area enclosed by the dashed line is the detection target area A of the obstacle detection sensor 47. In this embodiment, the height of the detection target area A from the road surface is set to, for example, 300 mm. This is so that the obstacle detection sensor 47 can detect a person crouching below the driver's cab 18. The obstacle detection sensor 47 is connected to the controller 41. When the driver's cab 18 rises to a height above a preset height, the obstacle detection sensor 47 is activated.

[0027] Next, the detection target area A will be described. The width of the detection target area A is set so that it can pass through the narrowest passage, and it is also set taking into account the error of the obstacle detection sensor 47. Specifically, the width of the detection target area A is the width of the pallet P plus the detection error of the obstacle detection sensor 47 when the fork 28 is supporting the pallet P, and is slightly larger than the width of the pallet P. The front-to-back length of the detection target area A differs between one (left) outer mast 19 side and the other (right) outer mast 19 side.

[0028] On one side of the outer mast 19, the length of the detection area A is the distance from the obstacle detection sensor 47 to the rear of the tip of the fork 28. The position of the obstacle detection sensor 47 behind the tip of the fork 28 is the distance obtained by adding the detection error of the obstacle detection sensor 47 to the tip of the pallet P when the fork 28 is supporting the pallet P. On the other side of the outer mast 19, the length of the detection area A is the distance from in front of the longitudinal center of the other leg 14 to the rear of the tip of the fork 28. Therefore, the detection area A is trapezoidal in plan view.

[0029] As shown in Figure 5, when the fork 28 is supporting the pallet P, the leading edge of the detection target area A is the distance from the tip of the pallet P by the detection error of the obstacle detection sensor 47 dF It is set to be positioned only a distance to the rear. The side edge of the detection target area A is set to be positioned laterally by a detection error of dW from the side edge of pallet P. dF The detection error dW is equal to this.

[0030] As shown in Figure 4, there is a blind spot, non-detection area B, below the driver's cab 18 where the obstacle detection sensor 47 cannot detect obstacles. Non-detection area B is roughly triangular in plan view. In this embodiment, a part of the driver's cab 18, including the area near the base of the other leg 14, is non-detection area B. To make non-detection area B as small as possible, the obstacle detection sensor 47 should be positioned as far outward and as far back as possible in the width direction.

[0031] Next, the detection of obstacles by the forklift 10 of this embodiment will be described. The operator gets into the driver's cab 18 and starts the forklift 10. Next, the operator moves the forklift 10 toward a place where picking work will be performed, such as a loading rack. The operator drives the forklift 10 by operating the accelerator lever 35 and the steering wheel 34. When the forklift 10 is driven normally, the driver's cab 18 is in the lowered position regardless of whether there is a load or not. When the forks 28 are supporting a pallet P loaded with cargo and driving, the operator raises the driver's cab 18 to a height where the forks 28 do not touch the ground.

[0032] When performing picking operations on a cargo rack, the operator raises the cab 18 to the position of the cargo rack where loading and unloading of cargo is required. The cab 18 is raised by the extension of the front lift cylinder 25, which raises the cab 18 relative to the inner mast 21, then the inner mast 21 rises relative to the middle mast 20, and finally the middle mast 20 rises relative to the outer mast 19 by the extension of the rear lift cylinder 23. The raising and lowering of the cab 18 is performed by the operator operating the cargo handling lever 36. When the cab 18 is raised to a predetermined height from the road surface, the obstacle detection sensor 47 starts scanning with a laser beam. The obstacle detection sensor 47 scans the laser beam over an area that includes at least the detection target area A.

[0033] In this embodiment, when the driver's cab 18 is raised or stopped, if the obstacle detection sensor 47 detects an obstacle in the detection area A, the controller 41 displays a warning on the display 37 indicating the presence of the obstacle. When the driver's cab 18 is lowered, if the obstacle detection sensor 47 detects an obstacle in the detection area A, the controller 41 emits a warning sound from the speaker of the display 37. Furthermore, if the driver's cab 18 is at a height of 2m or more above the road surface when lowered, the controller 41 emits a warning sound from the lower alarm buzzer 46 in addition to the warning display and warning sound on the display 37. The controller 41 also controls the display 37 to change the warning sound output pattern depending on whether the height of the driver's cab 18 when lowered is 2m or more or less than 2m.

[0034] Incidentally, potential obstacles detected by the obstacle detection sensor 47 include, for example, moving objects and people. If an obstacle exists in the non-detection area B, the obstacle detection sensor 47 will not detect the obstacle. However, for a moving object or person to enter the area below the driver's cab 18 in the non-detection area B, they would need to cross over the other leg 14, making it difficult for moving objects or people to enter the non-detection area B. Furthermore, even if a person enters the non-detection area B, their body movements will cause them to enter the detection target area A. If even a small part of their body enters the detection target area A, the obstacle detection sensor 47 will immediately detect the person as an obstacle.

[0035] The forklift 10 of this embodiment provides the following effects. (1) The obstacle detection sensor 47 is installed on the outside of the base of one (left) of the pair of outer masts 19. Therefore, even if the obstacle detection sensor 47 is installed only on the outside of the base of one outer mast 19, the area below the driver's cab 18 can be made into the detection target area A of the obstacle detection sensor 47, except for the area near the base of the other (right) outer mast 19 below the driver's cab 18. Furthermore, since the obstacle detection sensor 47 is installed on the outside of the base of one outer mast 19, it is not necessary to raise the driver's cab 18 when performing maintenance on the obstacle detection sensor 47. Therefore, during maintenance work, workers can access the obstacle detection sensor 47 without having to enter below the driver's cab 18.

[0036] (2) The detection target area A is an area below the driver's cab 18 that includes the entirety of one (left) leg 14 of a pair of left and right legs 14, and the area behind the base of the other (right) leg 14. For this reason, it is possible that the base of the other leg 14 may be outside the detection target area A, but it is very unlikely that an obstacle will go over the other leg 14 and enter below the driver's cab 18.

[0037] (3) Since the obstacle detection sensor 47 is attached to the mast support member 24 via the bracket 48, the obstacle detection sensor 47 can be attached and detached relatively easily. Also, since the obstacle detection sensor 47 does not protrude outward from the side of the vehicle body 11, it is easy to avoid interference with other objects while driving. Furthermore, in a plan view, the obstacle detection sensor 47 does not protrude outward from the outer edge of the bracket 48, making it even easier to suppress interference with other objects.

[0038] (4) The controller 41 controls the display 37 or the lower alarm buzzer 46 to issue a warning only when an obstacle is present below the driver's cab 18. Compared to a system where a warning is always issued during descent regardless of the presence of an obstacle, for example, workers below the driver's cab 18 can avoid becoming accustomed to the warning. Similarly, operators can avoid becoming accustomed to the warning.

[0039] (5) The detection area A is set based on the smallest passage that the forklift 10 can pass through, taking into account the error of the obstacle detection sensor 47, so that the detection area is not made wider than necessary. For example, even when passing through a narrow passage between shelves, there is almost no possibility of detecting the shelves as obstacles, and the efficiency of cargo handling operations is not reduced.

[0040] (6) Since only one obstacle detection sensor 47 is used, the manufacturing cost of the forklift 10 can be reduced compared to the case in which multiple obstacle detection sensors 47 are used.

[0041] (Second embodiment) Next, a forklift according to the second embodiment will be described. This embodiment differs from the first embodiment in that, in addition to the obstacle detection sensor being installed on the outside of the base of one outer mast, the obstacle detection sensor is also installed on the other outer mast. In this embodiment, for the same configuration as in the first embodiment, the description of the first embodiment will be used with reference, and the same reference numerals will be used.

[0042] As shown in Figure 6, the forklift 50 is equipped with an obstacle detection sensor 51 on the outside of the base of the right outer mast 19, which is the other of a pair of outer masts 19. Specifically, the obstacle detection sensor 47 is attached to the rear surface of the mast support member 24 via a bracket 52. Bracket 52 is identical to bracket 48. The obstacle detection sensor 51 is the same laser rangefinder (LRF) as the obstacle detection sensor 47. The detection target area C of the obstacle detection sensor 51 is linearly symmetrical to the detection target area A in a plan view, and the center line (not shown) passing through the center in the width direction of the vehicle body 11 is the axis of symmetry. Therefore, there is almost no area below the driver's cab 18 where obstacles cannot be detected.

[0043] As shown in Figure 6, in a plan view, parts of the detection target areas A and C overlap, but if the heights of the detection target areas A and C coincide, interference of the laser beams from the obstacle detection sensors 47 and 51 occurs, potentially leading to false detection. For this reason, in this embodiment, the bracket 52 is attached to the other mast support member 24 such that the other obstacle detection sensor 51 is at a higher height from the road surface than the other obstacle detection sensor 47. As shown in Figure 7, the angle between the imaginary line M connecting the laser emission parts of the obstacle detection sensors 47 and 51 and the horizontal line H of By setting it to 5 degrees, the height difference between the obstacle detection sensors 47 and 51 is set. The angle between the virtual line M and the horizontal line H is set according to various conditions such as the performance of the obstacle detection sensors 47 and 51 and the dimensions of the vehicle body 11.

[0044] In this embodiment, the obstacle detection sensor 47 is installed on the outside of the base of one outer mast 19, and the obstacle detection sensor 47 is installed on the outside of the base of the other outer mast 19, so that almost the entire area below the driver's cab 18 can be used as the detection area. In other words, compared to the first embodiment, the area in which obstacles cannot be detected can be reduced as much as possible.

[0045] Furthermore, in this embodiment, the detection heights of the obstacle detection sensors 47 and 51, which are installed on the outside of the bases of the left and right outer masts 19, are different. Therefore, the overlap of detection target areas A and C on the same plane can be avoided, and false detection of obstacles due to the overlap of detection target areas A and C can be prevented.

[0046] (Modified version of the second embodiment) Next, a forklift relating to a modified version of the second embodiment will be described. This embodiment differs from the second embodiment in that the detection height of the obstacle detection sensor is the same, but the detection target area is different. In this embodiment, for the same configuration as in the first embodiment, the description of the first embodiment will be used by reference, and the same reference numerals will be used.

[0047] In this modified forklift 60, one obstacle detection sensor 47 and the other obstacle detection sensor 51 are mounted on their respective mast support members 24 via brackets 48 and 52 so as to be at the same height. As shown in Figure 8, the width of the detection area D of one (left) obstacle detection sensor 47 and the width of the detection area E of the other (right) obstacle detection sensor 51 are less than half the width of the pallet P. A gap G is provided between the detection area D and the detection area E.

[0048] The detection area D of one obstacle detection sensor 47 is set to one side of the center in the width direction of the vehicle body 11, and the detection area E of the other obstacle detection sensor 51 is set to the other side of the center in the width direction of the vehicle body 11. In other words, the obstacle detection sensor 47 does not consider the area beyond the gap G as an obstacle detection area, and the obstacle detection sensor 51 does not consider the area beyond the gap G as an obstacle detection area. The gap G is set to a distance equivalent to the error of the obstacle detection sensors 47 and 51.

[0049] In this modified example, the obstacle detection sensors 47 and 51, each installed on the outside of the base of a pair of left and right outer masts 19, have the same detection height. The detection area D of one obstacle detection sensor 47 is set to one side of the widthwise center of the vehicle body 11, while the detection area E of the other obstacle detection sensor is set to the other side of the widthwise center of the vehicle body 11. Therefore, the detection areas D and E do not overlap at the same height. Thus, the laser beams of the obstacle detection sensors 47 and 51 do not interfere with each other, preventing false detection of obstacles due to the overlap of the detection areas D and E.

[0050] The present invention is not limited to the embodiments described above (including modifications), and various modifications are possible within the scope of the invention. For example, it may be modified as follows.

[0051] ○ In the above embodiments (including modified versions), the obstacle detection sensor was installed on the mast support member, but is not limited to this. The obstacle detection sensor may be installed, for example, on the outer mast, or on the leg. Furthermore, the obstacle detection sensor may be installed without using a bracket. ○ In the above embodiments (including modified examples), one side of the vehicle body's width direction is designated as the right and the other as the left, but this is not limited to this configuration. For example, one side of the vehicle body's width direction may be designated as the left and the other as the right. ○ In the above embodiments (including modified examples), the mast is a fully free three-stage mast having an outer mast, a middle mast, and an inner mast, but is not limited to this. The mast may also be a two-stage mast having an outer mast and an inner mast. ○ In the above embodiments (including modified versions), the cargo handling vehicle is configured such that the operator in the driver's cab faces the vehicle body, with the front of the operator being the forward direction and the rear of the operator (the leg) being the reverse direction. However, it is not limited to this configuration. The cargo handling vehicle may also be configured such that the operator in the driver's cab faces the leg, with the front of the operator being the forward direction and the rear of the vehicle body being the reverse direction. ○ The length of the detection target area A on one side of the outer mast may be the length from the obstacle detection sensor to the rear of the front end of the driver's cab. However, if the driver's cab is equipped with cargo handling equipment such as forks, it is preferable to do so as in the above embodiment (including modified versions). [Explanation of symbols]

[0052] 10, 50, 60 forklifts 11 Car body 12 Front wheels 14 Legs 15 Rear wheel 16 Mast Equipment 17 Mast 18 Driver's cab 19 Outer Mast 24 Mast support components 27. Highest Lift 28 Forks 34 Steering Wheel 36. Lifting lever 37 display 41 Controllers 44. Cargo handling lever sensor 46. ​​Lower alarm buzzer 47, 51 Obstacle detection sensors 48, 52 brackets A, C, D, E: Detection target areas B Non-detection area dF detection error dW detection error P Palette

Claims

1. A vehicle body equipped with drive wheels, A pair of left and right legs extending from one side of the vehicle body to the other, with wheels at the other end, A pair of left and right outer masts are positioned on the leg side of the vehicle body, A driver's cab that can be raised and lowered relative to the pair of outer masts on the left and right, An obstacle detection sensor for detecting obstacles below the driver's cab, A warning device that emits a warning, A cargo handling vehicle having a controller that controls the warning device to issue a warning when the obstacle detection sensor detects an obstacle, The obstacle detection sensor is installed on the outside of the base of at least one of the pair of left and right outer masts, The detection area in which the obstacle detection sensor detects an obstacle includes the area below the driver's cab. The controller is characterized in that when the obstacle detection sensor detects an obstacle in the detection area when the driver's cab is raised or stopped, it displays a warning on the warning device indicating the presence of an obstacle, and when the obstacle detection sensor detects an obstacle in the detection area when the driver's cab is lowered, it generates a warning sound on the warning device.

2. The cargo handling vehicle according to claim 1, characterized in that the detection target area is an area below the driver's cab that includes the entirety of one of the pair of left and right legs, and at least the portion of the other leg that is closer to the tip than the base.

3. A vehicle body equipped with drive wheels, A pair of left and right legs extending from one side of the vehicle body to the other, with wheels at the other end, A pair of left and right outer masts are positioned on the leg side of the vehicle body, A driver's cab that can be raised and lowered relative to the pair of outer masts on the left and right, An obstacle detection sensor for detecting obstacles below the driver's cab, A warning device that emits a warning, A cargo handling vehicle having a controller that controls the warning device to issue a warning when the obstacle detection sensor detects an obstacle, The obstacle detection sensors are installed on the outside of the bases of the left and right pair of outer masts, The detection area in which the obstacle detection sensor detects an obstacle includes the area below the driver's cab. A cargo handling vehicle characterized in that the obstacle detection sensors, each installed on the outside of the base of the left and right pair of outer masts, have different heights from the road surface in the detection target area.

4. A vehicle body equipped with drive wheels, A pair of left and right legs extending from one side of the vehicle body to the other, with wheels at the other end, A pair of left and right outer masts are positioned on the leg side of the vehicle body, A driver's cab that can be raised and lowered relative to the pair of outer masts on the left and right, An obstacle detection sensor for detecting obstacles below the driver's cab, A warning device that emits a warning, A cargo handling vehicle having a controller that controls the warning device to issue a warning when the obstacle detection sensor detects an obstacle, The obstacle detection sensors are installed on the outside of the bases of the left and right pair of outer masts, The detection area in which the obstacle detection sensor detects an obstacle includes the area below the driver's cab. The obstacle detection sensors, each installed on the outside of the base of the pair of left and right outer masts, have matching detection heights. The detection area of ​​the obstacle detection sensor is set to one side of the center in the width direction of the vehicle body. A cargo handling vehicle characterized in that the detection target area of ​​the other obstacle detection sensor is set to a position other than the center in the width direction of the vehicle body.

Images