cargo handling vehicle

Abstract

To provide a loading / unloading vehicle that allows an occupant to easily recognize an obstacle when a lift part is lowered.SOLUTION: A loading / unloading vehicle 10 includes a lift part 30, a mast device 40, a loading / unloading lever 50, a control device 60, and an obstacle sensor 93. The lift part 30 is formed by integrating a fork 32 with an operator's platform 31. The mast device 40 raises / lowers the lift part 30. The control device 60 controls the mast device 40 through an operation of the loading / unloading lever 50. The obstacle sensor 93 detects an obstacle 100 present below the operator's platform 31 when a lifted height of the operator's platform 31 is equal to or greater than a height H1. When the obstacle 100 is detected by the obstacle sensor 93, the control device 60 executes a lowering-speed limiting process for controlling the mast device 40 so as to limit a lowering speed V2 of the lift part 30.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Patent Document 1 describes a cargo handling vehicle. The cargo handling vehicle is equipped with a lifting section, a mast assembly, a loading lever, and a control device. The lifting section is an integrated unit of a fork and a driver's cab. The mast assembly raises and lowers the lifting section. The loading lever operates the mast assembly. The control device controls the mast assembly in response to the operation of the loading lever. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-1026 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if an obstacle is present below the cab when the elevator section is lowered, there is a risk that the cab will come into contact with the obstacle when the elevator section is lowered. It is difficult for the occupant in the cab to see the obstacle present below the cab. Therefore, a method has been studied that makes it easier for the occupant to recognize the obstacle when the elevator section is lowered. [Means for solving the problem]

[0005] A loading vehicle that solves the above problem is a loading vehicle that includes a lifting section in which the forks and driver's cab are integrated, a mast device that raises and lowers the lifting section, a loading lever, and a control device that controls the mast device in response to operation of the loading lever, and further includes an obstacle sensor that detects obstacles present below the driver's cab when the driver's cab is above a predetermined height, and when an obstacle is detected by the obstacle sensor, the control device executes a descent speed limiting process that controls the mast device to limit the descent speed of the lifting section.

[0006] According to the above configuration, when an obstacle is detected, a descent speed limiting process is executed to limit the descent speed of the lifting section, making it easier for the occupant to recognize the obstacle when the lifting section is descending.

[0007] The control device may execute the descent speed limiting process when the loading lever is operated in the descent command direction and an obstacle is detected by the obstacle sensor. According to the above configuration, when the descent speed of the lifting unit is limited by the execution of the descent speed limiting process, the descent speed of the lifting unit does not correspond to the amount of operation of the loading lever, which makes the occupant feel uncomfortable when operating the loading lever, making it easier for the occupant to recognize an obstacle.

[0008] In the above-mentioned loading vehicle, if the obstacle sensor changes from detecting an obstacle to not detecting an obstacle while the control device is executing the descent speed limiting process, the control device continues to execute the descent speed limiting process unless the operation of the loading lever in the descent command direction is stopped, and cancels the descent speed limiting process when the operation of the loading lever in the descent command direction is stopped.

[0009] According to the above configuration, if an obstacle is removed while an occupant is operating the cargo handling lever in the direction of the descent command, the descent speed limiting process is not canceled. In other words, even if an obstacle is removed while an occupant is operating the cargo handling lever in the direction of the descent command, the descent speed of the lifting unit does not increase, thereby preventing an unexpected shock from being applied to the occupant.

[0010] The above-mentioned loading vehicle is equipped with a first alarm unit that alerts the occupant of the presence of an obstacle, and a second alarm unit that alerts the occupant of the presence of an obstacle by means different from the first alarm unit, and when the descent speed limiting process is being executed and the loading lever is not operated in the descent command direction, the first alarm unit is activated while the second alarm unit is not activated, and when the descent speed limiting process is being executed and the loading lever is operated in the descent command direction, both the first alarm unit and the second alarm unit are activated.

[0011] According to the above configuration, when the descent speed limiting process is being executed, the occupant can be made more clearly aware of the presence of an obstacle below the cab. In particular, when the occupant intends to lower the lifting section, the second notification section is also activated in addition to the first notification section, making it easier for the occupant to be aware of the obstacle.

[0012] In the above-mentioned cargo handling vehicle, the notification pattern of the second notification unit when the amount of descent of the lifting unit is less than a specified value may be different from the notification pattern of the second notification unit when the amount of descent is equal to or greater than the specified value.

[0013] According to the above configuration, when the descent speed limiting process is being executed, it becomes easier for the occupants to more clearly recognize that the cab is approaching an obstacle. [Effects of the Invention]

[0014] According to this invention, it is possible to make the occupant more easily aware of obstacles when the lifting section is lowering. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. [Figure 2] FIG. [Figure 3] FIG. 2 is a schematic diagram showing the electrical configuration and mast assembly of the cargo handling vehicle. [Figure 4] 4 is a flowchart showing a process executed by a control device. [Figure 5] 4 is a flowchart showing a process executed by a control device. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, a specific embodiment of a cargo handling vehicle will be described with reference to FIGS. <Loading vehicle> 1 and 2, the cargo handling vehicle 10 is a picking lift. The cargo handling vehicle 10 includes a vehicle body 20, a lifting section 30, a mast device 40, a cargo handling lever 50, a control device 60, a display 81, a display warning device 82, and a worker warning device 83.

[0017] <Body> As shown in Fig. 1, the vehicle body 20 has a main body 21 and a pair of legs 22. The main body 21 forms the front part of the vehicle body 20. The pair of legs 22 extend rearward from the main body 21. The pair of legs 22 are provided with driven wheels 22a.

[0018] As shown in Fig. 2, the main body 21 of the vehicle body 20 is provided with drive wheels 21a, an on-board battery 23, and a traction motor 24. The traction motor 24 is driven by the on-board battery 23. The traction motor 24 rotates the drive wheels 21a, thereby causing the vehicle body 20 to travel. The cargo handling vehicle 10 is a battery vehicle. The drive wheels 21a also serve as steering wheels.

[0019] <Lifting section> As shown in FIG. 1, the lifting unit 30 has a cab 31 and a fork 32. The cab 31 is the area where a passenger sits. The cab 31 is located behind the main body 21. The cab 31 is provided between a pair of legs 22. The fork 32 is integral with the cab 31. The fork 32 extends rearward from the cab 31.

[0020] A net 33 and an instrument panel 34 are provided in front of the cab 31. The net 33 protects the front of the occupant while ensuring forward visibility. The instrument panel 34 is located below the net 33. The instrument panel 34 is provided with a load handling lever 50, a display 81, and a display warning device 82. The load handling lever 50 is a thumb lever type. The load handling lever 50 is operated to raise and lower the forks 32 together with the cab 31. The operation direction of the load handling lever 50 consists of an up command direction to raise the cab 31 and forks 32, and a down command direction to lower them. The lifting section 30 rises and falls in response to the operation of the load handling lever 50.

[0021] The display 81 makes a predetermined announcement to the occupants. The display 81 makes a predetermined announcement to the occupants, for example, by displaying characters. The display 81 makes a predetermined announcement to the occupants, for example, by flashing the entire display 81. The display 81 makes a predetermined announcement to the occupants, for example, by flashing displayed characters, icons, etc.

[0022] The display warning device 82 is provided as part of the display 81. The display 81 and the display warning device 82 are integrated. The display warning device 82 makes a predetermined announcement to the occupants by emitting a sound. The display warning device 82 is, for example, a speaker. The display warning device 82 may be omitted from the display 81. In this case, a speaker with a different configuration that replaces the display warning device 82 may be provided at any position on the cab 31.

[0023] <Mast equipment> As shown in Fig. 2, the mast assembly 40 has a mast 41. The mast 41 is arranged between the main body 21 and the cab 31. The mast 41 has an outer mast 41a and an inner mast 41b. The outer mast 41a is fixed to the vehicle body 20. A worker alarm 83 is attached to the outer mast 41a. The worker alarm 83 makes a predetermined announcement to workers near the cargo handling vehicle 10 by emitting a sound. The worker alarm 83 is, for example, a speaker.

[0024] The inner mast 41b is movable up and down relative to the outer mast 41a. A chain wheel (not shown) is provided on the upper part of the inner mast 41b. A chain (not shown) is hung on the chain wheel. One end of the chain is attached to the outer mast 41a, and the other end of the chain is attached to the driver's cab 31.

[0025] The mast assembly 40 includes a lift cylinder 42, a tank 43, an electromagnetic switching valve 44, a hydraulic pump 45, and an electric motor 46. The lift cylinder 42 is a hydraulic cylinder. The inner mast 41b moves up and down by supplying and discharging hydraulic oil to and from the lift cylinder 42. The tank 43 stores hydraulic oil. The lift cylinder 42 and the tank 43 are connected by an oil passage 49.

[0026] As shown in Fig. 3, the electromagnetic switching valve 44 is provided in an oil passage 49. The electromagnetic switching valve 44 is a valve that can be switched between an open position 44a having an orifice and a closed position 44b having a spring-loaded check valve. When the loading lever 50 is operated, the electromagnetic switching valve 44 is in the open position 44a, thereby connecting the upstream side and downstream side of the electromagnetic switching valve 44 in the oil passage 49. When the loading lever 50 is not operated, the electromagnetic switching valve 44 is in the closed position 44b, thereby blocking the upstream side and downstream side of the electromagnetic switching valve 44 in the oil passage 49.

[0027] As shown in FIG. 2 , the hydraulic pump 45 is provided in the oil passage 49 between the solenoid switching valve 44 and the tank 43. The hydraulic pump 45 is driven by an electric motor 46. The electric motor 46 is driven when the loading / unloading lever 50 is operated. When the electric motor 46 rotates in one direction, the hydraulic pump 45 rotates in one direction. As a result, the hydraulic pump 45 draws in hydraulic oil stored in the tank 43 and supplies the hydraulic oil to the lift cylinder 42 via the solenoid switching valve 44. When the electric motor 46 rotates in the other direction, the hydraulic pump 45 rotates in the other direction. As a result, the hydraulic pump 45 draws in hydraulic oil filled in the lift cylinder 42 and returns the hydraulic oil to the tank 43 via the solenoid switching valve 44. The hydraulic pump 45 is a bidirectionally rotatable pump. The electric motor 46 is a bidirectionally rotatable motor.

[0028] When the cargo handling lever 50 is operated in the lift instruction direction, the hydraulic pump 45 rotates in one direction, supplying hydraulic oil to the lift cylinder 42. As the hydraulic pressure in the lift cylinder 42 increases, the inner mast 41b moves upward. This causes the chain wheel (not shown) to move upward, raising the driver's cab 31 attached to the other end of the chain (not shown).

[0029] When the cargo handling lever 50 is operated in the downward direction and the hydraulic pump 45 rotates in the other direction, the hydraulic oil filled in the lift cylinder 42 is drawn into the hydraulic pump 45 via the electromagnetic switching valve 44 and returned to the tank 43. The hydraulic pressure in the lift cylinder 42 decreases, causing the inner mast 41b to move downward. This causes the chain wheel (not shown) to move downward, lowering the cab 31 attached to the other end of the chain (not shown). The mast assembly 40 raises and lowers the lifting section 30.

[0030] The absolute value of the rotation speed of the hydraulic pump 45 changes depending on the absolute value of the rotation speed n of the electric motor 46. The amount of hydraulic oil drawn from the tank 43 and supplied to the lift cylinder 42 changes depending on the absolute value of the rotation speed of the hydraulic pump 45. Also, the amount of hydraulic oil drawn from the lift cylinder 42 and returned to the tank 43 changes depending on the absolute value of the rotation speed of the hydraulic pump 45. The lower the absolute value of the rotation speed n of the electric motor 46, the more difficult it is for the hydraulic pressure of the lift cylinder 42 to increase or decrease. Therefore, the lower the absolute value of the rotation speed n of the electric motor 46, the lower the ascent speed V1 or descent speed V2 of the lifting unit 30.

[0031] <Electrical configuration of cargo handling vehicle> 3, the cargo handling vehicle 10 further includes a lifting height sensor 91, a cargo handling lever sensor 92, an obstacle sensor 93, a rotation speed sensor 94, a first drive circuit 95, and a second drive circuit 96. The lifting height sensor 91 detects the lifting height H of the underside of the cab 31. The cargo handling lever sensor 92 detects the direction and amount of operation of the cargo handling lever 50.

[0032] As shown in FIG. 2 , the obstacle sensor 93 is attached to the outer mast 41 a. The obstacle sensor 93 is disposed at a height H1 from the ground. The obstacle sensor 93 detects an obstacle 100 present below the cab 31 when the cab 31 is at a predetermined height or higher. The obstacle sensor 93 detects an obstacle 100 present below the cab 31 when the lifting height H of the cab 31 is at or above height H1. The obstacle sensor 93 detects the obstacle 100 when the lifting unit 30 is lowered. The obstacle sensor 93 is a sensor such as an ultrasonic sensor, a Doppler sensor, or an optical sensor. The obstacle sensor 93 is suitably a sensor that detects the obstacle 100 by emitting sound, light, or radio waves within a target range and detecting the reflection from the obstacle 100. The obstacle sensor 93 is disposed on the outer mast 41 a so that the cab 31 and the ground are not included in the target range when detecting the obstacle 100. The height H1 is a value slightly smaller than the minimum height of the obstacle 100 detected by the obstacle sensor 93.

[0033] As shown in FIG. 3 , the rotation speed sensor 94 is provided on the electric motor 46. The rotation speed sensor 94 detects the rotation speed n of the electric motor 46. The first drive circuit 95 is a circuit that switches the solenoid switching valve 44 between an open position 44a and a closed position 44b. The second drive circuit 96 is a circuit that drives the electric motor 46. The second drive circuit 96 is a circuit that controls the rotation speed n and the rotation direction of the electric motor 46. The lifting height sensor 91, the loading lever sensor 92, the obstacle sensor 93, the rotation speed sensor 94, the first drive circuit 95, and the second drive circuit 96 are electrically connected to the control device 60. The display 81, the display warning device 82, and the worker warning device 83 are electrically connected to the control device 60.

[0034] The control device 60 includes a processor 61 such as a CPU or GPU, and a storage unit 62 including RAM, ROM, etc. The storage unit 62 stores program code or instructions configured to cause the processor 61 to execute processing. The storage unit 62, i.e., the computer-readable medium, includes any available medium accessible by a general-purpose or special-purpose computer. The control device 60 may be configured with hardware circuits such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The control device 60, which is a processing circuit, may include one or more processors that operate according to a computer program, one or more hardware circuits such as ASICs or FPGAs, or a combination thereof.

[0035] The control device 60 basically drives the first drive circuit 95 and the second drive circuit 96 based on the detection result of the cargo handling lever sensor 92. When the control device 60 detects a detection result from the cargo handling lever sensor 92 that the cargo handling lever 50 is being operated, the control device 60 outputs a command S1on to the first drive circuit 95 to switch the electromagnetic switching valve 44 to the open position 44a. As a result, the electromagnetic switching valve 44 is switched to the open position 44a. When the control device 60 detects a detection result from the cargo handling lever sensor 92 that the cargo handling lever 50 is not being operated, the control device 60 outputs a command S1off to the first drive circuit 95 to switch the electromagnetic switching valve 44 to the closed position 44b. As a result, the electromagnetic switching valve 44 is switched to the closed position 44b.

[0036] The control device 60 calculates a target value n* for the rotation speed n of the electric motor 46 in accordance with the operation direction of the load handling lever 50 detected by the load handling lever sensor 92 and the operation amount of the load handling lever 50. The absolute value of the target value n* is determined by the operation amount of the load handling lever 50. The control device 60 outputs a command S2 to the second drive circuit 96 so that the rotation speed n of the electric motor 46 becomes the target value n*. The second drive circuit 96 then causes the rotation speed n of the electric motor 46 to become the target value n*. The control device 60 controls the mast device 40 in accordance with the operation of the load handling lever 50.

[0037] <Processing performed by the control device> The following describes the processing executed by the control device 60. Note that the description will be given on the assumption that the cab 31 is lowered when the cab 31 is in a raised state.

[0038] As shown in FIG. 4, the control device 60 first executes the process of step S11. In the process of step S11, the control device 60 determines whether the lift height H is equal to or greater than height H1. In the process of step S11, the control device 60 acquires the detection result of the lift height sensor 91. If the control device 60 determines in the process of step S11 that the lift height H is not equal to or greater than height H1 (step S11: NO), the control device 60 ends the process. If the control device 60 determines in the process of step S11 that the lift height H is equal to or greater than height H1 (step S11: YES), the control device 60 proceeds to the process of step S12.

[0039] In the process of step S12, the control device 60 determines whether or not an obstacle 100 has been detected. In the process of step S12, the control device 60 acquires the detection result of the obstacle sensor 93. If the control device 60 determines in the process of step S12 that the obstacle 100 has not been detected (step S12: NO), the control device 60 ends the process. If the control device 60 determines in the process of step S12 that the obstacle 100 has been detected (step S12: YES), the control device 60 proceeds to the process of step S13.

[0040] The control device 60 executes a descent speed limiting process in the process of step S13. Hereinafter, the process of step S13 will be referred to as the descent speed limiting process S13. The descent speed limiting process S13 is a process executed when an obstacle 100 is detected by the obstacle sensor 93. When the control device 60 executes the descent speed limiting process S13, the cargo handling lever 50 may be operated in the descent command direction, the cargo handling lever 50 may not be operated, or the cargo handling lever 50 may be operated in the up command direction. The control device 60 executes the descent speed limiting process S13 when the cargo handling lever 50 is operated in the descent command direction and an obstacle 100 is detected by the obstacle sensor 93. The point in time when the cargo handling lever 50 is operated in the descent command direction is any point before or after the process of step S12.

[0041] The control device 60 also executes the descent speed limiting process S13 even when the cargo handling lever 50 is not operated and an obstacle 100 is detected by the obstacle sensor 93. The control device 60 also executes the descent speed limiting process S13 even when the cargo handling lever 50 is operated in the upward command direction and an obstacle 100 is detected by the obstacle sensor 93. The point in time at which the cargo handling lever 50 is operated in the upward command direction is any point before or after the processing of step S12.

[0042] The descent speed limiting process S13 is a process for setting a mode for calculating the target value n* having the absolute value of either of the numerical values ​​by comparing the absolute value of the target value n* with the limiting value Nth when the load lever sensor 92 detects that the load lever 50 has been operated in the descent command direction. The limiting value Nth is pre-stored in the memory unit 62. The limiting value Nth is a constant value. The limiting value Nth is greater than zero. The limiting value Nth indicates the absolute value of the rotation speed n of the electric motor 46. The limiting value Nth is a value previously confirmed to be a descent speed V2 of the lifting unit 30 that allows a passenger to board the cab 31 stably. When the load lever 50 is not operated or when the load lever 50 is operated in the up command direction, the control device 60 executes the descent speed limiting process S13 while controlling the mast device 40 according to the direction and amount of operation of the load lever 50.

[0043] In the descent speed limiting process S13, if the absolute value of the target value n* exceeds the limit value Nth when the cargo handling lever 50 is operated in the descent command direction, the control device 60 replaces the absolute value of the target value n* with the limit value Nth. Then, the control device 60 calculates the target value n* whose absolute value has been replaced with the limit value Nth, and outputs a command S2 corresponding to the target value n* to the second drive circuit 96. Then, the second drive circuit 96 sets the absolute value of the rotation speed n of the electric motor 46 to the limit value Nth. In other words, in the descent speed limiting process S13, if the absolute value of the target value n* exceeds the limit value Nth when the cargo handling lever 50 is operated in the descent command direction, the control device 60 controls the mast assembly 40 to achieve a descent speed V2 that is lower than the descent speed V2 based on the amount of operation of the cargo handling lever 50.

[0044] In the descent speed limiting process S13, if the absolute value of the target value n* is equal to or less than the limit value Nth when the cargo handling lever 50 is operated in the descent command direction, the control device 60 does not replace the absolute value of the target value n* with the limit value Nth. The control device 60 then outputs a command S2 corresponding to the calculated target value n* to the second drive circuit 96. The second drive circuit 96 then sets the rotation speed n of the electric motor 46 to the target value n*. In the descent speed limiting process S13, if the absolute value of the target value n* is equal to or less than the limit value Nth when the cargo handling lever 50 is operated in the descent command direction, the control device 60 controls the mast assembly 40 to achieve a descent speed V2 corresponding to the amount of operation of the cargo handling lever 50.

[0045] The absolute value of the target value n* being equal to or less than the limit value Nth is equivalent to the descent speed V2 of the lifting section 30 being such that a passenger can board the cab 31 stably. The descent speed limiting process S13 controls the mast assembly 40 to limit the descent speed V2 of the lifting section 30. "Limiting the descent speed V2 of the lifting section 30" means limiting the descent speed V2 of the lifting section 30 to a speed that allows a passenger to board the cab 31 stably. When an obstacle 100 is detected by the obstacle sensor 93, the control device 60 controls the mast assembly 40 to limit the descent speed V2 of the lifting section 30. After executing the descent speed limiting process S13, the control device 60 proceeds to step S14.

[0046] In the process of step S14, the control device 60 determines whether the obstacle 100 has disappeared. In the process of step S14, the control device 60 acquires the detection result of the obstacle sensor 93. If the control device 60 determines in the process of step S14 that the obstacle 100 has not disappeared (step S14: NO), the control device 60 continues the descent speed limiting process S13. If the control device 60 determines in the process of step S14 that the obstacle 100 has disappeared (step S14: YES), the control device 60 proceeds to the process of step S15.

[0047] In the process of step S15, the control device 60 determines whether or not the operation of the cargo handling lever 50 has stopped. In the process of step S15, the control device 60 acquires the detection result of the cargo handling lever sensor 92. If the control device 60 determines in the process of step S15 that the operation of the cargo handling lever 50 has not stopped (step S15: NO), it continues the descent speed limiting process S13.

[0048] If the control device 60 determines in the processing of step S15 that the operation of the cargo handling lever 50 has stopped (step S15: YES), the control device 60 proceeds to the processing of step S16. Note that a case where the result of the processing of step S15 is YES is assumed to be a case where the cargo handling lever 50 has been continuously operated in the downward command direction before the execution of the descent speed limiting processing S13 and then stopped, or a case where the cargo handling lever 50 has been continuously operated in the downward command direction after the execution of the descent speed limiting processing S13 and then stopped. Also, a case where the result of the processing of step S15 is YES is assumed to be a case where the cargo handling lever 50 has not been operated before the execution of the descent speed limiting processing S13. Furthermore, a case where the result of the processing of step S15 is YES is assumed to be a case where the cargo handling lever 50 has been continuously operated in the upward command direction before the execution of the descent speed limiting processing S13 and then stopped, or a case where the cargo handling lever 50 has been continuously operated in the upward command direction after the execution of the descent speed limiting processing S13 and then stopped.

[0049] The control device 60 cancels the descent speed limiting process S13 in the process of step S16. The control device 60 continues the descent speed limiting process S13 until it is determined in the process of step S14 that the obstacle 100 has disappeared and it is determined in the process of step S15 that the operation of the loading lever 50 has stopped.

[0050] If the obstacle 100 changes from being detected by the obstacle sensor 93 to being not detected while the control device 60 is executing the descent speed limiting process S13, the control device 60 continues to execute the descent speed limiting process S13 unless the loading lever 50 is stopped. Then, if the obstacle 100 changes from being detected by the obstacle sensor 93 to being not detected while the control device 60 is executing the descent speed limiting process S13, and the loading lever 50 is stopped, the control device 60 cancels the descent speed limiting process S13.

[0051] Assume a situation in which the cargo handling lever 50 has been continuously operated in the instructed descent direction before or after the execution of the descent speed limiting process S13. In this situation, if the obstacle sensor 93 changes from detecting an obstacle 100 to not detecting it while the control device 60 is executing the descent speed limiting process S13, the control device 60 continues to execute the descent speed limiting process S13 unless the operation of the cargo handling lever 50 in the instructed descent direction is stopped. In this situation, if the obstacle sensor 93 changes from detecting an obstacle 100 to not detecting it while the control device 60 is executing the descent speed limiting process S13, the control device 60 cancels the descent speed limiting process S13 when the operation of the cargo handling lever 50 in the instructed descent direction is stopped.

[0052] <Announcement to passengers when descent speed limiting process is in progress> The announcement to the occupants when the descent speed limiting process S13 is being executed will be described below together with the process executed by the control device 60. Note that the process executed by the control device 60 described below ends when the descent speed limiting process S13 is released in step S16.

[0053] As shown in Fig. 5, the control device 60 executes the process of step S21 when the descent speed limiting process S13 is executed. In the process of step S21, the control device 60 displays on the display 81 a message indicating that the descent speed limiting process S13 is being executed. The display 81 notifies the occupant that the descent speed limiting process S13 is being executed. In other words, the display 81 notifies the occupant of the presence of an obstacle 100. After executing the process of step S21, the control device 60 proceeds to the process of step S22.

[0054] In the processing of step S22, the control device 60 determines whether the cargo handling lever 50 has been operated. In the processing of step S22, the control device 60 determines whether the cargo handling lever 50 has been operated in the downward command direction. In the processing of step S22, the control device 60 acquires the detection result of the cargo handling lever sensor 92. If the control device 60 determines in the processing of step S22 that the cargo handling lever 50 has not been operated in the downward command direction (step S22: NO), the control device 60 ends the processing with a message on the display 81 indicating that the descent speed limiting processing S13 is being executed. If the control device 60 determines in the processing of step S22 that the cargo handling lever 50 has been operated in the downward command direction (step S22: YES), the control device 60 proceeds to the processing of step S23.

[0055] In the process of step S23, the control device 60 determines whether the descent amount D of the lifting unit 30 is equal to or greater than a specified value Dth. The control device 60 has been accumulating the number of rotations n of the electric motor 46 since the descent speed limiting process S13 was executed. A map showing the relationship between the accumulated value of the number of rotations n of the electric motor 46 and the descent amount D of the lifting unit 30 is stored in the memory unit 62 of the control device 60. In the process of step S23, the control device 60 calculates the descent amount D of the lifting unit 30 by referring to the accumulated value of the number of rotations n in the map. If the control device 60 determines in the process of step S23 that the descent amount D is not equal to or greater than the specified value Dth (step S23: NO), the control device 60 proceeds to the process of step S24. If the control device 60 determines in the process of step S23 that the descent amount D is equal to or greater than the specified value Dth (step S23: YES), the control device 60 proceeds to the process of step S25. The specified value Dth is a value smaller than the height H1.

[0056] In the processing of step S24, the control device 60 activates the display warning device 82. In the processing of step S24, the control device 60 causes the display warning device 82 to emit a sound every first period. The first period is, for example, two seconds. The first period is not limited to two seconds and may be changed as appropriate. The display warning device 82 notifies the occupant that the descent speed limiting process S13 is being executed. The display warning device 82 notifies the occupant of the presence of an obstacle 100. The warning pattern in which the display warning device 82 emits a sound every first period is defined as a first pattern. After executing the processing of step S24, the control device 60 executes the processing of step S23 again.

[0057] In the processing of step S25, the control device 60 activates the display warning device 82 and also activates the worker alarm device 83. In the processing of step S25, the control device 60 causes the display warning device 82 to emit a sound every second period. The second period is, for example, one second. The second period may be changed as appropriate as long as it is shorter than the first period. The notification pattern in which the display warning device 82 emits a sound every second period is defined as the second pattern.

[0058] When the descent speed limiting process S13 is being executed, if the loading lever 50 is not operated in the descent direction, the display 81 is activated but the display warning device 82 is not activated. When the descent speed limiting process S13 is being executed, if the loading lever 50 is operated in the descent direction, both the display 81 and the display warning device 82 are activated. The display 81 is a first notification unit. The display warning device 82 is a second notification unit that notifies the occupant of the presence of an obstacle 100 by a means different from the display 81.

[0059] When the amount of descent D of the lifting / lowering unit 30 is less than the specified value Dth, the display warning device 82 operates in a first pattern. When the amount of descent D of the lifting / lowering unit 30 is equal to or greater than the specified value Dth, the display warning device 82 operates in a second pattern. In other words, the notification pattern (first pattern) of the display warning device 82 when the amount of descent D of the lifting / lowering unit 30 is less than the specified value Dth is different from the notification pattern (second pattern) of the display warning device 82 when the amount of descent D of the lifting / lowering unit 30 is equal to or greater than the specified value Dth.

[0060] In the processing of step S25, the control device 60 causes the worker alarm 83 to emit a sound. The worker alarm 83 notifies the occupants and workers near the cargo handling vehicle 10 that the descent speed limiting process S13 is being executed. The worker alarm 83 notifies workers near the cargo handling vehicle 10 of the presence of the obstacle 100. After executing the processing of step S25, the control device 60 ends the processing. As long as the control device 60 continues to execute the descent speed limiting process S13, it repeatedly executes the processing of steps S21, S22, S23, S24, and S25 related to announcements to the occupants.

[0061] [Actions and Effects of This Embodiment] The operation and effects of this embodiment will be described. (1) When the descent speed limiting process S13 is executed to limit the descent speed V2 of the lifting / lowering unit 30, the descent speed V2 of the lifting / lowering unit 30 does not correspond to the amount of operation of the cargo handling lever 50. Therefore, by making the operation of the cargo handling lever 50 feel strange to the occupant, it is possible to make the occupant more easily aware of the obstacle 100.

[0062] (2) If the obstacle 100 changes from being detected by the obstacle sensor 93 to being not detected by the obstacle sensor 93 while the control device 60 is executing the descent speed limiting process S13, the control device 60 continues to execute the descent speed limiting process S13 unless the operation of the cargo handling lever 50 in the descent direction is stopped. If the obstacle 100 changes from being detected by the obstacle sensor 93 to being not detected by the obstacle sensor 93 while the control device 60 is executing the descent speed limiting process S13, the control device 60 cancels the descent speed limiting process S13 when the operation of the cargo handling lever 50 in the descent direction is stopped. Therefore, if the obstacle 100 is removed while the occupant is operating the cargo handling lever 50 in the descent direction, the descent speed limiting process S13 is not canceled. In other words, even if the obstacle 100 is removed while the occupant is operating the cargo handling lever 50 in the descent direction, the descent speed V2 of the lifting unit 30 does not increase, thereby preventing the occupant from experiencing an unexpected shock.

[0063] (3) When the descent speed limiting process S13 is being executed, if the cargo handling lever 50 is not operated in the descent direction, the display 81 is activated but the display warning device 82 is not activated. When the descent speed limiting process S13 is being executed, if the cargo handling lever 50 is operated in the descent direction, both the display 81 and the display warning device 82 are activated. Therefore, when the descent speed limiting process S13 is being executed, the occupant can more clearly recognize that there is an obstacle 100 below the cab 31. In particular, when the occupant intends to lower the lifting section 30, the display warning device 82 is activated in addition to the display 81, making it easier for the occupant to recognize the obstacle 100.

[0064] (4) The notification pattern of the display warning device 82 when the descent amount D of the lifting / lowering unit 30 is less than the specified value Dth is different from the notification pattern of the display warning device 82 when the descent amount D of the lifting / lowering unit 30 is equal to or greater than the specified value Dth. This makes it easier for the occupant to more clearly recognize that the cab 31 is approaching the obstacle 100 while the descent speed limiting process S13 is being executed.

[0065] (5) When the presence of the obstacle 100 is announced to the passengers by sound, if the passengers become accustomed to the sound, their awareness of the announcement will decrease. In other words, excessive announcements to the passengers will reduce the effectiveness of the announcement.

[0066] In this embodiment, when the descent speed limiting process S13 is being executed and the loading lever 50 is not operated to lower the lifting section 30, the display 81 is activated but the display warning device 82 is not activated. This makes it easier for the occupants to remain aware of the announcements while suppressing excessive announcements to the occupants.

[0067] (6) When the amount of descent D of the lifting section 30 is equal to or greater than the specified value Dth, the worker alarm 83 is activated, thereby alerting workers near the cargo handling vehicle 10 to the presence of the obstacle 100. Therefore, even if the occupants are not very aware of the display 81 and the display alarm 82, workers near the cargo handling vehicle 10 can call the occupants' attention.

[0068] Furthermore, if the amount of descent D of the lifting section 30 is less than the specified value Dth, the worker alarm 83 will not be activated. This makes it easier for workers near the cargo handling vehicle 10 to remain aware of the announcements while suppressing excessive announcements.

[0069] (7) The descent speed limiting process S13 limits the descent speed V2 of the lifting unit 30 to a speed that allows a passenger to stably board the cab 31. This reduces the possibility that the cab 31 will come into contact with the obstacle 100.

[0070] [Example of change] This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0071] A vibrator that generates vibrations may be used as the second notification unit instead of the display warning device 82. The vibrator may be used as the first notification unit instead of the display 81. The vibrator may be provided on an accelerator lever or a steering wheel provided on the cargo handling vehicle 10. The presence of the obstacle 100 may be notified to the occupant by the vibration of the vibrator.

[0072] The display warning device 82 may operate in the second pattern when the amount of descent D of the lift-down unit 30 is less than the specified value Dth, and may operate in the first pattern when the amount of descent D of the lift-down unit 30 is equal to or greater than the specified value Dth. In other words, it is only necessary that the notification pattern of the display warning device 82 when the amount of descent D of the lift-down unit 30 is less than the specified value Dth is different from the notification pattern of the display warning device 82 when the amount of descent D of the lift-down unit 30 is equal to or greater than the specified value Dth. Note that the notification pattern of the display warning device 82 when the amount of descent D of the lift-down unit 30 is less than the specified value Dth may be the same as the notification pattern of the display warning device 82 when the amount of descent D of the lift-down unit 30 is equal to or greater than the specified value Dth.

[0073] Although the control device 60 calculates the descent amount D of the lifting unit 30 based on the integrated value of the rotation speed n of the electric motor 46, this is not limited to this. For example, the cargo handling vehicle 10 may be equipped with an encoder that detects the amount of movement of the cab 31. The encoder may calculate the descent amount D of the cab 31 from the time when the descent speed limiting process S13 was executed, and the control device 60 may obtain the descent amount D from the encoder. The method of calculating the descent amount D of the lifting unit 30 may be changed as appropriate.

[0074] For example, the display warning device 82 may be used as the first notification unit, and the display 81 may be used as the second notification unit. In such a modification, the control device 60 activates the display warning device 82 in the process of step S21. Then, the control device 60 activates the display 81 in the processes of steps S24 and S25.

[0075] The display warning device 82 and the vibrator may be used as the second notification unit. The display 81 and the vibrator may be used as the first notification unit. As long as the notification means of the first notification unit and the notification means of the second notification unit are different, the first notification unit and the second notification unit may include any configuration.

[0076] When the descent speed limiting process S13 is being executed, both the first and second notification units may be activated regardless of whether the loading lever 50 is being operated or not. In the processing of steps S15 and S22, the control device 60 determines whether the loading lever 50 has been operated based on the detection result of the loading lever sensor 92, but this is not limited to this. For example, the loading vehicle 10 may be equipped with a sensor that detects movement of the cab 31. The control device 60 may determine whether the loading lever 50 has been operated based on the detection result of the sensor. The method of determining whether the loading lever 50 has been operated may be changed as appropriate.

[0077] The control device 60 does not have to execute the descent speed limiting process S13 when the loading lever 50 is not operated and the obstacle sensor 93 detects an obstacle 100. The control device 60 does not have to execute the descent speed limiting process S13 when the loading lever 50 is operated in the upward command direction and the obstacle sensor 93 detects an obstacle 100. It is sufficient for the control device 60 to execute the descent speed limiting process S13 when the loading lever 50 is operated in the downward command direction and the obstacle sensor 93 detects an obstacle 100.

[0078] The control device 60 may cancel the descent speed restriction process S13 if the obstacle 100 is no longer detected by the obstacle sensor 93 while the descent speed restriction process S13 is being executed. In other words, the process of step S15 may be omitted from the processes executed by the control device 60.

[0079] The limit value Nth may be a value that decreases as the descent amount D of the lifting / lowering unit 30 increases. In other words, the descent speed V2 of the lifting / lowering unit 30 may decrease as the descent amount D increases. When changing the limit value Nth in this way, it is preferable to store a map summarizing the correlation between the descent amount D and the limit value Nth in the storage unit 62. Then, it is preferable to calculate the limit value Nth by referring to the calculated descent amount D in the map.

[0080] Although the descent speed V2 of the lifting unit 30 is limited by limiting the rotation speed n of the electric motor 46, this is not a limitation. For example, the electromagnetic switching valve 44 may be replaced with an oil control valve capable of adjusting the flow rate of hydraulic oil. When the loading lever 50 is operated in the downward direction, the control device 60 controls the oil control valve to restrict the hydraulic oil filled in the lift cylinder 42 from flowing toward the tank 43. This modification restricts the hydraulic pressure of the lift cylinder 42 from decreasing, thereby restricting the descent speed V2 of the lifting unit 30. When this modification is adopted, the oil passage 49 includes a supply oil passage for supplying hydraulic oil from the tank 43 to the oil control valve and a return oil passage for returning hydraulic oil from the oil control valve to the tank 43. The hydraulic pump 45 may be provided in the supply oil passage. Because the hydraulic pump 45 is used to draw hydraulic oil from the tank 43, it may be replaced with a pump that rotates in only one direction. When the hydraulic pump 45 is changed to a pump that rotates in only one direction, the electric motor 46 may also be changed to a motor that rotates in only one direction.

[0081] The obstacle sensor 93 may be attached to a structure other than the outer mast 41a. The attachment position of the obstacle sensor 93 may be changed as appropriate as long as the obstacle 100 located below the cab 31 can be detected. [Explanation of symbols]

[0082] 10...loading vehicle, 30...lifting unit, 31...driver's cab, 32...fork, 40...mast device, 50...loading lever, 60...control device, 81...display as first notification unit, 82...display warning device as second notification unit, 93...obstacle sensor, 100...obstacle, V2...descent speed of lifting unit, S13...descent speed limit processing, D...descent amount of lifting unit, Dth...specified value.

Claims

1. a lifting section in which the forks and the driver's cab are integrated; a mast device that raises and lowers the lifting section; Loading lever, a control device that controls the mast device in response to operation of the cargo handling lever, The vehicle further includes an obstacle sensor that detects an obstacle present below the driver's cab when the driver's cab is at or above a predetermined height, the obstacle sensor detects the obstacle by emitting sound, light, or radio waves from the obstacle sensor to a target range and detecting reflections from the obstacle; The control device is characterized in that, when an obstacle is detected by the obstacle sensor, it executes a descent speed limiting process for controlling the mast device so as to limit the descent speed of the lifting section.

2. a lifting section in which the forks and the driver's cab are integrated; a mast device that raises and lowers the lifting section; Loading lever, a control device that controls the mast device in response to operation of the cargo handling lever, The vehicle further includes an obstacle sensor that detects an obstacle present below the driver's cab when the driver's cab is at or above a predetermined height, when the cargo handling lever is operated in a descent instruction direction and the obstacle sensor detects an obstacle, the control device executes a descent speed limiting process for controlling the mast assembly to limit the descent speed of the lifting section; The control device is characterized in that, when the obstacle sensor changes from detecting an obstacle to not detecting an obstacle while executing the descent speed limiting process, it continues to execute the descent speed limiting process unless the operation of the loading lever in the descent command direction is stopped, and cancels the descent speed limiting process when the operation of the loading lever in the descent command direction is stopped.

3. a lifting section in which the forks and the driver's cab are integrated; a mast device that raises and lowers the lifting section; Loading lever, a control device that controls the mast device in response to operation of the cargo handling lever, The vehicle further includes an obstacle sensor that detects an obstacle present below the driver's cab when the driver's cab is at or above a predetermined height, the control device executes a descent speed limiting process for controlling the mast assembly to limit the descent speed of the lifting section when the obstacle sensor detects an obstacle; a first notification unit that notifies an occupant of the presence of an obstacle; a second notification unit that notifies an occupant of the presence of an obstacle by a means different from that of the first notification unit, When the descent speed limiting process is being executed, if the loading lever is not operated in the descent instruction direction, the first notification unit is activated while the second notification unit is not activated, A loading vehicle characterized in that when the descent speed limiting process is being executed and the loading lever is operated in the descent instruction direction, both the first alarm unit and the second alarm unit are activated.

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