Material handling vehicles

Abstract

To provide a cargo handling vehicle with high convenience which can achieve both of mounting promotion on a guide bar of a safety belt and maintenance of working efficiency.SOLUTION: A cargo handling vehicle includes: a vehicle body; a control platform which is provided in a front section of the vehicle body and can be lifted with respect to the vehicle body; a cargo handling device which is provided in the control platform; a head guard which is provided above the control platform; a cargo handling motor 23 which lifts the control platform; a traveling motor 13 which is mounted in the vehicle body and travels the vehicle body; and a controller 42 which controls the cargo handling motor 23 and the traveling motor 13. The head guard has a guide bar which can suspend a hook section of a safety belt and a photoelectric sensor 60 which optically detects the presence or absence of the hook section in the guide bar. The controller 42 limits at least one operation of a travel operation and a cargo handling operation when a lifting height of the control platform is a threshold or more and the photoelectric sensor 60 does not detect the hook section.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] This invention relates to a handling vehicle.

Background Art

[0002] As a conventional technology of a handling vehicle, for example, a picking forklift disclosed in Patent Document 1 is known. The picking forklift disclosed in Patent Document 1 has a safety belt attachment device that fastens a safety belt worn by an operator boarding a cab that can move up and down together with the forks of the picking forklift. The safety belt attachment device includes a safety bar to which the safety belt is fastened, an optical sensor that detects whether the safety belt is fastened to the safety bar, and a red light and an audible alarm that alert that the safety belt is not fastened to the safety bar.

[0003] When the safety belt is fastened to the safety bar, the light from the light projecting part of the optical sensor is blocked by the hook part of the safety belt, and it is detected that the safety belt is fastened to the safety bar. When the safety belt is not fastened to the safety bar, the light from the light projecting part of the optical sensor is not blocked, it is detected that the safety belt is not fastened, and the red light and the audible alarm are activated. Therefore, according to the safety belt attachment device of Patent Document 1, it is detected whether the safety belt is fastened to the safety belt attachment part, and an alarm is issued when the safety belt is not fastened. For this reason, an operator boarding the cab of the picking forklift does not forget to wear the safety belt, and it is said that the wearing of the safety belt is prompted.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in material handling vehicles such as the picking forklift described in Patent Document 1, the relationship between the presence or absence of the safety harness hook on the guide bar and vehicle control is not considered. In other words, it is merely a technology that issues a warning (alarm) when the safety harness hook is not detected on the guide bar, regardless of the operation of the material handling vehicle.

[0006] This invention has been made in view of the above-mentioned problems, and the object of this invention is to provide a highly convenient cargo handling vehicle that can achieve both the promotion of attaching safety belts to guide bars and the maintenance of work efficiency. [Means for solving the problem]

[0007] To solve the above problems, the present invention provides a cargo handling vehicle comprising: a vehicle body; a driver's cab provided at the front of the vehicle body and movable up and down relative to the vehicle body; a cargo handling device provided on the driver's cab; a head guard provided above the driver's cab; a cargo handling motor for raising and lowering the driver's cab; a cargo handling lever operated in directions corresponding to the raising and lowering movements for raising and lowering the driver's cab, and a neutral position; a driving motor mounted on the vehicle body for driving the vehicle body; and a controller for controlling the cargo handling motor and the driving motor, wherein the head guard comprises a guide bar that enables the suspension of the hook portion of a safety belt, and a photoelectric sensor that optically detects the presence or absence of the hook portion on the guide bar; and the controller limits the operation of at least one of the driving operation by the driving motor and the cargo handling operation by the cargo handling motor when the height of the driver's cab is above a threshold and the photoelectric sensor does not detect the hook portion. If the aforementioned cargo handling operation is restricted, As a restriction on the operation of the aforementioned cargo handling operation, the cargo handling motor is controlled so that the driver's cab cannot be raised and only lowering is possible, thereby restricting the operation of the cargo handling operation. after The operating restriction is released when the lifting height of the driver's cab is below the threshold, or when the hook is detected and the cargo handling lever is in the neutral position. Furthermore, if the lifting height of the driver's cab is below a threshold and the photoelectric sensor does not detect the hook portion, the driving operation and the cargo handling operation will not be restricted. It is characterized by the following:

[0008] In this invention, the controller can encourage the operator to attach the safety harness to the guide bar by limiting the operation of at least one of the driving operation and the cargo handling operation when the lifting height of the driver's cab is above a threshold and the photoelectric sensor does not detect the hook portion. Furthermore, if the lifting height of the driver's cab is below the threshold, the driving operation and cargo handling operation are not limited regardless of whether the hook portion is detected or not, and good work efficiency can be maintained. Furthermore, when the controller restricts the operation of cargo handling, it controls the cargo handling motor to prevent the driver's cab from rising. Therefore, even if the hook is not detected, the driver's cab can be lowered, and the vehicle can be set to a height where the driving and cargo handling operations are not restricted.

[0009] Furthermore, in the above-mentioned cargo handling vehicle, the controller may be configured to control the driving motor so that the vehicle speed is below a preset upper limit vehicle speed as an operating limitation for the driving operation. In this case, when the controller limits the operation of the vehicle, it controls the travel motor to keep the vehicle speed below a preset upper limit. Therefore, even if, for example, the photoelectric sensor malfunctions during loading and unloading operations, the vehicle can be reliably moved away from the shelf.

[0011] Furthermore, in the above-mentioned cargo handling vehicle, the vehicle body is the The accelerator lever is operated for driving. The system includes a warning device which, when the photoelectric sensor does not detect the hook portion, is controlled by the controller to issue a warning, and the controller is the Accelerator lever and the load handling lever The warning device may be configured to control itself so that it does not issue a warning when it is not being operated. In this case, the controller is Accelerator lever and load / load lever The warning device is controlled so that it does not emit a warning when it is not being operated. Accelerator lever and load / load lever Warnings are issued only in limited situations where the system is being operated, thus reducing the annoyance caused by warnings. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a highly convenient cargo handling vehicle that can achieve both the promotion of attaching safety harnesses to guide bars and the maintenance of work efficiency. [Brief explanation of the drawing]

[0013] [Figure 1]This is a side view of the order-picking type forklift according to this embodiment. [Figure 2] This is a perspective view of the order-picking type forklift according to this embodiment. [Figure 3] This is a perspective view of the main parts of the order-picking type forklift according to this embodiment. [Figure 4] This block diagram shows the electrical configuration of an order-picking type forklift according to this embodiment. [Figure 5] This flowchart illustrates the process for limiting the operation of an order-picking type forklift according to this embodiment. [Modes for carrying out the invention]

[0014] The material handling vehicle according to this embodiment will be described below with reference to the drawings. The material handling vehicle in this embodiment is an order-picking type forklift. The directions "front and back," "left and right," and "up and down" are indicated based on the state in which the operator of the order-picking type forklift is seated in the driver's cab and facing the forward direction of the order-picking type forklift.

[0015] As shown in Figure 1, the order-picking type forklift (hereinafter simply referred to as "forklift") 10, used as a material handling vehicle, has a body 11, and front wheels 12 are provided at the front of the body 11. The front wheels 12 are both drive wheels and steering wheels, and are located near the center in the left-right direction of the body 11. The body 11 is equipped with a drive motor 13, which is an electric motor for driving, and the drive motor 13 drives the front wheels 12. The body 11 is also equipped with a steering device (not shown), which steers the front wheels 12. At the rear of the body 11 are a pair of left and right legs 14 that extend backward, and rear wheels 15 are provided at the tips of the legs 14. The rear wheels 15 are driven wheels that can roll.

[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 has an outer mast 19 and an inner mast 20 that moves up and down with respect to the outer mast 19. At the upper end of the inner mast 20, a sprocket 21 on which a chain 22 is mounted is provided. The operator's cab 18 is suspended by the chain 22. The raising and lowering of the inner mast 20 is performed by driving a cargo handling motor 23 mounted on the vehicle body 11. When the inner mast 20 moves up and down with respect to the outer mast 19, the operator's cab 18 moves up and down.

[0017] Next, the operator's cab 18 will be described. As shown in FIG. 2, the operator's cab 18 is a substantially square platform on which an operator can board. A pair of forks 24 as cargo handling tools are provided at the lower part of the operator's cab 18. The forks 24 extend rearward from the lower part of the operator's cab 18. A pair of left and right pillars 25 are erected at the front part of the operator's cab 18. The pillars 25 support a head guard 35 described later. Between the left and right pillars 25, a front wall portion 26 erected from the operator's cab 18 is provided. The front wall portion 26 is about half the height of the pillar 25, and a metal protection net 27 is provided above the front wall portion 26.

[0018] As shown in FIG. 2, an instrument panel 28 is provided on the front wall portion 26. In addition to a steering wheel 29 and an accelerator lever 30, a cargo handling lever 31 and a display 32 are provided on the instrument panel 28. An operation pedal 33 is provided on the operator's cab 18. The steering wheel 29 is a wheel that an operator operates when changing the direction during travel. The accelerator lever 30 is a lever for accelerator operation when the forklift 10 moves forward or backward. The cargo handling lever 31 is a lever for raising and lowering the operator's cab 18. The accelerator lever 30 and the cargo handling lever 31 correspond to operation parts.

[0019] The display 32 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 32 can also emit light and blink. Also, since the display 32 generates warning sounds, it corresponds to a warning device. Near the upper part of the front wall portion 26, a pair of left and right side gates 34 for operator protection are provided. The side gate 34 is an L-shaped gate bar that can move up and down, and is fixed at a retracted position which is the upward rotation position and a guard position which is the downward rotation position. In FIG. 1, the side gate 34 in the guard position is shown, and in FIG. 2, the side gate 34 in the retracted position is shown.

[0020] Here, the head guard 35 will be described. As shown in FIG. 3, the head guard 35 has a frame body 36, a plurality of horizontal partition members 37 that partition the space defined by the frame body 36 back and forth, and a vertical partition member 38 that divides the space defined by the frame body 36 into two parts left and right. In FIG. 3, for the sake of convenience of explanation, the rear part of the frame body 36 is shown omitted.

[0021] As shown in FIG. 3, the head guard 35 has a guide bar 39 for suspending the hook portion 51 of the safety belt 50 that an operator wears when boarding the driver's cab 18. The safety belt 50 has a body belt portion (not shown) worn on the operator's body, a hook portion 51 suspended on the guide bar 39, a rope portion 52 connected to the body belt, and a connecting portion 53 that connects the hook portion 51 and the rope portion 52. The hook portion 51 includes a hook-shaped hook body 54, a stopper body 55 for opening and closing the opening of the hook body 54, and a through hole 56 for connection with the connecting portion 53. After pushing in the stopper body 55 and then hooking the hook body 54 on the guide bar 39, when the stopper body 55 returns to its original position, the hook portion 51 will not come off the guide bar 39.

[0022] In this embodiment, the guide bar 39 is provided in the head guard 35 between the rear of the frame 36 and the rearmost horizontal partition member 37. The guide bar 39 allows the hook portion 51 to move back and forth in one direction. The guide bar 39 in this embodiment has a plurality of guide members 40, 41 that are arranged substantially parallel to each other.

[0023] The head guard 35 is equipped with a photoelectric sensor 60 that detects the presence or absence of a hook portion 51 on the guide bar 39. As shown in Figure 3, the photoelectric sensor 60 has a light-emitting unit 62 that emits sensor light L and a light-receiving unit 61 that receives the emitted sensor light L. The light-emitting unit 62 is provided on the head guard 35 via an L-shaped light-emitting bracket 63. The light-emitting unit 62 is located to the right of the guide members 40 and 41, and the optical axis of the sensor light L emitted from the light-emitting unit 62 is in the left-right direction. The light-receiving unit 61 is provided on the head guard 35 via an L-shaped light-receiving bracket 64. The light-receiving unit 61 is located to the left of the guide members 40 and 41 and is positioned to receive the sensor light L emitted from the light-emitting unit 62. Note that the left-right positions of the light-emitting unit 62 and the light-receiving unit 61 relative to the guide members 40 and 41 may be changed. Alternatively, the photoelectric sensor 60 may utilize a diffuse reflection type photoelectric sensor in which the light-emitting unit 62 and the light-receiving unit 61 are integrated. In that case, a reflector (for example, a mirror) that reflects the sensor light L is installed on the opposite side of the guide members 40 and 41.

[0024] Next, the electrical configuration of the forklift 10 will be described. As shown in Figure 4, the forklift 10 has a controller 42 that controls various parts of the forklift 10. The controller 42 includes a CPU 43 and a storage unit 44 consisting of RAM and ROM, etc. The controller 42 may also include dedicated hardware, such as an application-specific integrated circuit (ASIC), that performs at least some of the various processes. The controller 42 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.

[0025] The memory unit 44 stores program code or commands configured to cause the CPU 43 to execute processing. The memory unit 44 stores various programs for controlling each part of the forklift 10. The controller 42 is electrically connected to the travel motor 13, the cargo handling motor 23, and the display 32.

[0026] Incidentally, the steering wheel 29 is equipped with a steering sensor 45 that detects the amount of steering, and the steering sensor 45 is connected to the controller 42. The accelerator lever 30 is equipped with an accelerator sensor 46 that detects the amount of accelerator, and the accelerator sensor 46 is connected to the controller 42. In addition, the cargo handling lever 31 is equipped with a cargo handling lever sensor 47 that detects the amount of operation of the cargo handling lever 31, and the cargo handling lever sensor 47 is connected to the controller 42. Furthermore, the side gate sensor 48 that detects the retracted position and guard position of the side gate 34 is equipped, and the side gate sensor 48 is connected to the controller 42.

[0027] The controller 42 receives an operation signal from the accelerator sensor 46 based on the operation of the accelerator lever 30 and controls the rotational speed of the travel motor 13. As a result, the forklift 10 travels in the direction of travel corresponding to the direction of operation of the accelerator lever 30 at a speed corresponding to the amount of operation. The controller 42 receives an operation signal from the cargo handling lever sensor 47 based on the operation of the cargo handling lever 31 and controls the rotational speed of the cargo handling motor 23. As a result, the forklift 10 performs an upward or downward movement in the upward or downward direction corresponding to the direction of operation of the cargo handling lever 31 at a speed corresponding to the amount of operation. The lifting height of the driver's cab 18 is transmitted to the controller 42 based on the rotational speed of the cargo handling motor 23. The controller 42 also receives signals from the side gate sensor 48 indicating the detection of the retracted position and guard position of the side gate 34.

[0028] Next, the operating limitations of the forklift 10 according to this embodiment will be described. As shown in the flowchart of Figure 5, the controller 42 detects the lifting height H of the driver's cab 18 when the forklift 10 is in operation (step S101). The lifting height H of the driver's cab 18 is detected based on the rotational speed of the cargo handling motor 23. Next, the controller 42 determines whether the detected lifting height H is greater than or equal to a preset threshold T (step S102). The threshold T is stored in the controller 42 and can be set, for example, based on the definition of working at heights of 2m or more as defined in the Industrial Safety and Health Act, and the threshold T can be set to less than 2m.

[0029] When the controller 42 determines that the lifting height H is greater than or equal to the threshold T, it then determines whether or not the hook portion 51 is on the guide bar 39 by detection by the photoelectric sensor 60 (step S103). If the controller 42 determines that the hook portion 51 is not on the guide bar 39, it restricts the operation of the forklift 10 (step S104). If, in step S102, the controller 42 determines that the lifting height H is less than the threshold T, or if, in step S103, it determines that the hook portion 51 is present, it returns to step S101.

[0030] To explain the operational restrictions of the forklift 10 in more detail, the controller 42 controls the drive motor 13 so that the forklift 10 cannot travel beyond a preset upper speed limit. In other words, the controller 42 limits the vehicle speed. In addition, as another operational restriction, the controller 42 controls the load handling motor 23 so that the driver's cab 18 cannot be raised and only the lowering movement of the driver's cab 18 is allowed. Furthermore, in addition to the operational restrictions, the controller 42 activates the display 32 to generate a warning sound. When operational restrictions are in place, the controller 42 controls the display 32 so that a warning sound is generated when at least one of the accelerator lever 30 and the load handling lever 31 is operated.

[0031] After the operation restriction is imposed, the controller 42 determines whether or not the hook portion 51 is on the guide bar 39 by detection by the photoelectric sensor 60 (step S105). If the controller 42 determines that the hook portion 51 is on the guide bar 39, it determines whether or not the load handling lever 31 is in the neutral position (step S106). If the controller 42 determines that the load handling lever 31 is in the neutral position, it releases the operation restriction (step S107). With the operation restriction released, the process returns to step S101. In step S105, if the controller 42 determines that the hook portion 51 is not on the guide bar 39, the controller 42 then determines whether the detected lifting height H is less than the threshold T (step S108). If the controller 42 determines that the lifting height H is less than the threshold T, it releases the operation restriction of the forklift 10. If the controller 42 determines in step S108 that the lifting height H is not less than the threshold T, it continues the operation restriction. Furthermore, if it is determined in step S106 that the cargo handling lever 31 is not in the neutral position, the process returns to step S104.

[0032] Next, the operation of the forklift 10 in this embodiment will be described. When the operator of the forklift 10 operates the forklift 10, they board the driver's cab 18 and then hook the hook portion 51 of the safety harness 50 onto the guide bar 39 to suspend it. When the hook portion 51 is suspended from the guide bar 39, the sensor light L emitted from the light-emitting portion 62 of the photoelectric sensor 60 is blocked, and the light-receiving portion 61 cannot receive the sensor light L. The controller 42 determines that the hook portion 51 is on the guide bar 39 due to the blocking of the sensor light L.

[0033] When the hook section 51 is suspended from the guide bar 39, the forklift 10 is not subject to any operational restrictions. When an operator seated in the cab 18 operates the accelerator lever 30 in the direction corresponding to the direction of travel, the forklift 10 travels at a speed corresponding to the amount the accelerator lever 30 is operated. Also, when the load handling lever 31 is operated, the load handling motor 23 rotates according to the amount the load handling lever 31 is operated. The direction of rotation of the load handling motor 23 corresponds to the direction in which the load handling lever 31 is operated. In other words, the cab 18 moves up or down at a speed corresponding to the amount of operation in the lifting direction corresponding to the direction in which the load handling lever 31 is operated. The lifting height H of the cab 18 is detected based on the rotation speed of the load handling motor 23.

[0034] When the detected lifting height H of the cab 18 is greater than or equal to a threshold T, and the hook portion 51 is not suspended from the guide bar 39, the forklift 10 is subject to operational restrictions. When the controller 42 determines that the lifting height H of the cab 18 is greater than or equal to a threshold T, and the hook portion 51 is not on the guide bar 39, it controls the travel motor 13 so that the forklift 10 cannot travel beyond a preset upper speed limit. Furthermore, when the controller 42 determines that the lifting height H of the cab 18 is greater than or equal to a threshold T, and the hook portion 51 is not on the guide bar 39, it controls the cargo handling motor 23 so that the lifting operation of the cab 18 is disabled, and only the lowering operation is possible.

[0035] When the forklift 10 is under operational restrictions, the controller 42 releases the restrictions when the operator suspends the hook portion 51 from the guide bar 39. However, if the loading operation is continuing by operating the loading lever 31, the controller 42 will not release the operational restrictions on the forklift 10 even if the hook portion 51 is suspended from the guide bar 39 and the sensor light is blocked. Instead, the controller 42 will release the restrictions only after the loading lever 31 is returned to the neutral position.

[0036] If the operator's cab 18 faces a shelf that is, for example, above a threshold T, and the operator is performing a picking operation, and the hook portion 51 detaches from the guide bar 39, the controller 42 will determine that the hook portion 51 is not on the guide bar 39, and the forklift 10 will be restricted from operating. At this time, even if the operator operates the accelerator lever 30, the forklift 10 will travel at a speed limited to below a preset upper limit. In addition, if the operator operates the load handling lever 31 in the direction corresponding to the lifting operation, the display 32 will activate and a warning sound will be emitted.

[0037] When the operator moves the load handling lever 31 in the direction corresponding to the downward movement, the driver's cab 18 lowers. When the lifting height H of the driver's cab 18 is greater than or equal to the threshold T and it is determined that the hook portion 51 is not on the guide bar 39, the display 32 activates when the accelerator lever 30 and the load handling lever 31 are operated. In addition, if the photoelectric sensor 60 malfunctions in such a way that it is determined that the lifting height H of the driver's cab 18 is greater than or equal to the threshold T and the hook portion 51 is not on the guide bar 39, the forklift 10 will also be subject to operational restrictions.

[0038] In the forklift 10 of this embodiment, when the detected lifting height H of the driver's cab 18 is less than the threshold T, the forklift 10 is not subject to operational restrictions, regardless of whether or not the hook portion 51 is present on the guide bar 39. In other words, if the detected lifting height H of the driver's cab 18 is less than the threshold T, the vehicle speed is not restricted, and the lifting and lowering of the driver's cab 18 is free within the range of less than the threshold T, even if the hook portion 51 is not suspended from the guide bar 39.

[0039] The forklift 10 according to this embodiment provides the following effects. (1) When the lifting height H of the operator's cab 18 is greater than or equal to the threshold T, and the photoelectric sensor 60 does not detect the hook portion 51, the controller 42 can restrict the operation of the driving and loading operations, thereby encouraging the operator to attach the safety harness 50 to the guide bar 39. Furthermore, if the lifting height H of the operator's cab 18 is less than the threshold T, the driving and loading operations are not restricted regardless of whether the hook portion 51 is detected or not, and the forklift 10 can maintain good work efficiency.

[0040] (2) The controller 42 controls the travel motor 13 so that the vehicle speed is below a preset upper limit as an operating restriction for the travel operation. For this reason, even if the photoelectric sensor 60 malfunctions during loading and unloading operations on a shelf, the forklift 10 can be reliably moved away from the shelf.

[0041] (3) The controller 42 controls the cargo handling motor 23 to prevent the driver's cab 18 from rising as an operation restriction for cargo handling operations. Therefore, even if the hook portion 51 is not detected by the guide bar 39, the driver's cab 18 can be lowered to a height where the driving operation and cargo handling operation are not restricted.

[0042] (4) The vehicle body 11 includes an accelerator lever 30 operated for driving, a cargo handling lever 31 operated for cargo handling, and a display 32 controlled by the controller 42 to emit a warning sound when the photoelectric sensor 60 does not detect the hook portion 51. The controller 42 controls the display 32 so as not to emit a warning when the accelerator lever 30 and the cargo handling lever 31 are not being operated. As a result, the warning sound is emitted only in limited situations when the accelerator lever 30 and the cargo handling lever 31 are being operated, reducing the annoyance of the operator caused by the warning sound.

[0043] (5) Even if the photoelectric sensor 60 malfunctions during loading and unloading operations on the shelf, causing the sensor to mistakenly determine that the hook portion 51 is not on the guide bar 39 when it is, movement at or below the upper limit vehicle speed is still possible, and the forklift 10 can move away from the shelf.

[0044] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the invention. For example, the following modifications may be made.

[0045] ○ In the above embodiment, an order-picking type forklift was used as an example of a material handling vehicle, but it is not limited to this. Any type or model of material handling vehicle that has a guide bar for suspending the hook portion of a safety harness is acceptable. ○ In the above embodiment, a display was used as an example of a warning device, and an example of generating a warning sound as a warning was described, but the invention is not limited to this. Warnings from a warning device may also be visual warnings, such as the illumination or flashing of lights. Warning sounds and visual warnings may also be combined. Furthermore, warnings may be represented by graphics or icons on the display, or multiple warning devices may be provided. ○ In the above embodiment, a warning is issued when the operating unit is operated and the cargo handling vehicle is subject to operational restrictions, but this is not limited to this. For example, a warning may always be issued when the cargo handling vehicle is subject to operational restrictions. ○ In the above embodiment, the lifting height of the driver's cab was determined based on the rotational speed of the cargo handling motor, but this is not limited to this. The lifting height of the driver's cab may be detected using a reel-type lifting height sensor or a limit switch, and the means of obtaining the lifting height are flexible. ○ In the above embodiment, the controller restricted the operation of the travel motor and the cargo handling motor when the lifting height of the driver's cab was above a threshold and the photoelectric sensor did not detect the hook portion, but it is not limited to this. For example, when the lifting height of the driver's cab was above a threshold and the photoelectric sensor did not detect the hook portion, only the cargo handling operation could be restricted. [Explanation of Symbols]

[0046] 10 Forklifts 11 Car body 13. Motor for driving 16 Mast Equipment 18 Driver's cab 23. Motor for cargo handling 24 Forks 30 Accelerator lever 31. Loading lever 32 displays 34 Side gate 35 Headguard 39 Guide Bars 42 controllers 46 Accelerator sensor 47. Cargo handling lever sensor 50 Safety Harness 51 Hook section 60 Photoelectric Sensors 61 Light receiving part 62. Lighting Unit H Lift height L Sensor light T threshold

Claims

1. The car body and, A driver's cab is provided at the front of the vehicle body and is movable up and down relative to the vehicle body, A cargo handling device provided in the driver's cab, A head guard is provided above the driver's cab, A cargo handling motor for raising and lowering the aforementioned driver's cab, A cargo handling lever that is operated in a direction corresponding to the upward and downward movements for raising and lowering the driver's cab, and in a neutral position, A motor mounted on the vehicle body and used to propel the vehicle body, A cargo handling vehicle having a cargo handling motor and a controller for controlling the travel motor, The aforementioned head guard is A guide bar that enables the suspension of the hook portion of the safety harness, The system includes a photoelectric sensor that optically detects the presence or absence of the hook portion in the guide bar, The controller, when the lifting height of the driver's cab is above a threshold and the photoelectric sensor does not detect the hook portion, restricts the operation of at least one of the traveling operation by the traveling motor and the cargo handling operation by the cargo handling motor. If the cargo handling operation is restricted, the cargo handling motor is controlled to prevent the driver's cab from rising and to allow only downward movement as a restriction on the cargo handling operation. After the aforementioned cargo handling operation is restricted, if the lifting height of the driver's cab is below a threshold, or if the hook portion is detected and the cargo handling lever is in the neutral position, the restriction is released. A cargo handling vehicle characterized in that, when the lifting height of the driver's cab is below a threshold and the photoelectric sensor does not detect the hook portion, the driving operation and the cargo handling operation are not restricted.

2. The cargo handling vehicle according to claim 1, characterized in that the controller controls the driving motor so that the vehicle speed is less than or equal to a preset upper limit vehicle speed as an operating limitation for the driving operation.

3. The vehicle body includes an accelerator lever operated for the aforementioned driving operation, The system includes a warning device that, when the photoelectric sensor does not detect the hook portion, is controlled by the controller to issue a warning, The cargo handling vehicle according to claim 1 or 2, characterized in that the controller controls the warning device so as not to issue a warning when the accelerator lever and the cargo handling lever are not being operated.

Images