Material handling vehicles

Abstract

To provide a cargo handling vehicle that can avoid contact with overhead obstacles while suppressing a decrease in work efficiency. [Solution] A cargo handling vehicle 1 comprising a vehicle body 2, a cargo handling device 3, a control unit 4, and a sensor unit 5, wherein the sensor unit 5, during lifting and lowering operations, sets a first area in the upper front of the vehicle body 2 and a second area in the lower front of the vehicle body 2 to detect the upper end of the cargo handling device 3, and when the upper end is detected in the second area, during driving operations, sets a third area behind the second area to detect an obstacle above the work area, and when the upper end is detected in the first area, during driving operations, sets a fourth area higher than the third area behind the first and second areas to detect an obstacle above, and the control unit 4, when an obstacle above is detected in the third or fourth area, stops the vehicle body 2 from moving or limits the vehicle speed.

Description

Technical Field

[0001] The present invention relates to a material handling vehicle such as a forklift.

Background Art

[0002] As a conventional material handling vehicle, for example, the one described in Patent Document 1 is known. The material handling vehicle described in Patent Document 1 detects obstacles in the traveling direction. Specifically, the material handling vehicle described in Patent Document 1 calculates the height H2 of the mast based on the height of the obstacle sensor, calculates a first line connecting the position at a first distance Lf from the obstacle sensor in the traveling direction and the obstacle sensor, calculates a second line connecting the position at a height H2 away from the above position in the height direction and the obstacle sensor, and calculates an angle θf formed by the first line and the second line. When an obstacle is detected by the obstacle sensor within the range of the angle θf, the material handling vehicle described in Patent Document 1 prohibits or stops traveling.

[0003] Also, the material handling vehicle described in Patent Document 1 also detects upper obstacles. Specifically, the material handling vehicle described in Patent Document 1 calculates a first height H4 lower than the height to an obstacle above the material handling vehicle based on the height of the obstacle sensor, and calculates a second height H6 to the upper end of the mast based on the height of the obstacle sensor. When the second height H6 is greater than or equal to the first height H4, the material handling vehicle described in Patent Document 1 prohibits or stops the raising of the mast.

[0004] The material handling vehicle described in Patent Document 1 can avoid contact with upper obstacles. However, in the detection of obstacles in the traveling direction, the material handling vehicle described in Patent Document 1 detects an obstacle at a certain distance ahead and prohibits or stops traveling. As a result, even when approaching a wall or a shelf in the work area, the traveling is prohibited or stopped. As a result, in a narrow material handling work site, traveling prohibition or traveling stop frequently occurs in the material handling vehicle described in Patent Document 1, and the work efficiency is significantly reduced.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-111138 [Overview of the project] [Problems that the invention aims to solve]

[0006] The present invention has been made in view of the above circumstances, and its objective is to provide a cargo handling vehicle that can avoid contact with overhead obstacles and suppress a decrease in work efficiency. [Means for solving the problem]

[0007] To solve the above problems, the cargo handling vehicle according to the present invention is A vehicle body that performs driving operations within a predetermined work area, A cargo handling device provided on the front side of the vehicle body that performs a lifting operation, A control unit that controls the aforementioned travel operation and the aforementioned lifting operation, A sensor unit that detects objects in a detection area above the vehicle body, A cargo handling vehicle equipped with, The aforementioned sensor unit is During the aforementioned lifting and lowering operation, a first area is set at the front upper level of the vehicle body and a second area is set at the front lower level of the vehicle body to detect the upper end of the cargo handling device. If the upper end is detected in the second area, a third area is set behind the second area during the driving operation to detect obstacles above the work area. If the upper end is detected in the first area, during the driving operation, a fourth area higher than the third area is set behind the first and second areas to detect the upper obstacle. The control unit is characterized in that, when the overhead obstacle is detected in the third area or the fourth area, it stops the vehicle from moving or limits the vehicle speed.

[0008] In the aforementioned cargo handling vehicle, The aforementioned sensor unit is The upper end position of the third area is set to be the same as or above the upper end position of the second area. The upper end position of the fourth area can be configured to be at the same position as or above the upper end position of the first area.

[0009] In the aforementioned cargo handling vehicle, The control unit outputs a cargo handling operation signal to the sensor unit during the lifting and lowering operation. The aforementioned sensor unit is If the cargo handling operation signal is not input and the upper end is detected in the second area, the second area is set without setting the first area. The system can be configured to set the first area and the second area when no cargo handling operation signal is input and the upper end is detected in the first area.

[0010] In the aforementioned cargo handling vehicle, The control unit outputs a reverse signal to the sensor unit when the vehicle body is moving in reverse. The aforementioned sensor unit is If the reverse signal is input and the upper end is detected in the second area, the second area and the third area are set. The system can be configured to set the first area, the second area, and the fourth area when the reverse signal is input and the upper end is detected in the first area.

[0011] In the aforementioned cargo handling vehicle, The aforementioned sensor unit is When the cargo handling device is detected in the first area, a first detection signal is output. When the cargo handling device is detected in the second area, a second detection signal is output. When the overhead obstacle is detected in the third area or the fourth area, a third detection signal is output. It can be configured to include a signal line that inputs the outputted first detection signal and the second detection signal to itself.

[0012] In the handling vehicle, The sensor unit outputs the first detection signal, the second detection signal, and the third detection signal to the control unit, The control unit can be configured to limit the vehicle speed of the vehicle body when the first detection signal or the second detection signal is input.

[0013] In the handling vehicle, The control unit, When the first detection signal is input, the upper limit speed during reverse travel of the vehicle body is limited to the first speed, When the second detection signal is input without the first detection signal being input, the upper limit speed can be configured to be limited to a second speed greater than the first speed.

Advantages of the Invention

[0014] According to the present invention, it is possible to provide a handling vehicle that can avoid contact with upper obstacles and suppress a decrease in work efficiency.

Brief Description of the Drawings

[0015] [Figure 1] A forklift according to the first embodiment, where (A) is a side view and (B) is a plan view. [Figure 2] A block diagram of the sensor unit and the control unit according to the first embodiment. [Figure 3] A diagram showing a detection area during lifting and lowering operations. [Figure 4] A diagram showing a detection area when the lifting and lowering operation stops and the traveling stops. [Figure 5] A diagram showing a detection area during a traveling operation (reverse). [Figure 6] A forklift according to the second embodiment, where (A) is a side view and (B) is a plan view. [Figure 7]This is a block diagram of the sensor unit and control unit according to the second embodiment. [Modes for carrying out the invention]

[0016] Hereinafter, embodiments of the cargo handling vehicle according to the present invention will be described with reference to the attached drawings.

[0017] [First Embodiment] Figure 1 shows a forklift 1 according to the first embodiment of the present invention. The forklift 1 of the first embodiment is a counterbalanced type forklift and corresponds to the "cargo handling vehicle" of the present invention. The forklift 1 performs driving and cargo handling operations within a predetermined work area.

[0018] The work area is an area within any building, such as a factory or warehouse. Above the work area, there are obstacles C (hereinafter referred to as "upper obstacles C") such as a low ceiling, gate, or protrusion. In addition, the work area is equipped with several shelves (not shown), on which cargo W, etc., is stored.

[0019] The forklift 1 comprises a vehicle body 2, a cargo handling device 3, a control unit 4, and a sensor unit 5.

[0020] The vehicle body 2 is equipped with front and rear wheels at the bottom and a driver's seat and head guard at the top. The front wheels are drive wheels driven by a traction motor, and the rear wheels are steering wheels steered (turned) by a steering motor. The driver's seat is the operator's seat, and the head guard is a protective frame to protect the operator in the driver's seat from falling objects.

[0021] Vehicle body 2 is equipped with an accelerator and a brake at the driver's feet. The accelerator is an accelerator pedal configured to be operated by the operator in the driver's seat by pressing it with their foot. When the accelerator is in the ON state (pedal pressed), it accelerates vehicle body 2 according to the amount of pedal depression (accelerator opening), while when it switches from the ON state to the OFF state (pedal not pressed), it generates a weak regenerative brake to decelerate vehicle body 2. The brake is a brake pedal configured to be operated by the operator in the driver's seat by pressing it with their foot. When the brake is in the ON state (pedal pressed), it generates a stronger regenerative brake than the accelerator's regenerative brake to decelerate vehicle body 2, while when it is in the OFF state, it does not generate regenerative brake. By operating the accelerator and / or brake, the operator can make vehicle body 2 perform driving actions such as acceleration and deceleration.

[0022] The vehicle body 2 is equipped with a steering wheel, forward / reverse levers, and cargo handling levers (tilt lever and lift lever) in front of the driver's seat. The steering wheel is connected to the rear wheels via a steering control mechanism 4C, which will be described later. By rotating the steering wheel, the operator can change the direction of the rear wheels (turning angle) according to the direction of rotation. The forward / reverse lever is located below the steering wheel and switches the vehicle body 2's movement between forward and reverse. When the operator tilts the forward / reverse lever forward (forward position) and turns on the accelerator, the vehicle body 2 can move forward. When the operator tilts the forward / reverse lever backward (reverse position) and turns on the accelerator, the vehicle body 2 can move backward. The cargo handling lever is connected to the cargo handling device 3 via a cargo handling control mechanism 4B, which will be described later. By operating the cargo handling lever, the operator can make the cargo handling device 3 perform cargo handling operations.

[0023] The cargo handling device 3 comprises a mast, a backrest and forks, a tilt cylinder, and a lift cylinder, and performs cargo handling operations. The cargo handling operations include raising and lowering the mast and forks.

[0024] The mast is located on the front side of the vehicle body 2 and raises and lowers the forks. The mast consists of an outer mast and an inner mast. The outer mast has a pair of left and right guide rails extending vertically and a cross beam connecting the upper ends of the guide rails. The inner mast has a pair of left and right rails extending vertically and a cross beam (connecting member) connecting the upper ends of the rails. The inner mast is located inside the guide rails of the outer mast and moves up and down along the guide rails of the outer mast. The outer mast does not move up or down.

[0025] The backrest is a frame designed to prevent the load W loaded on the forks from shifting backward, and is equipped with a lift bracket at its lower part. The lift bracket supports the forks and moves up and down along the mast. That is, when the mast (inner mast) moves up and down, the backrest (including the lift bracket) and the forks move up and down. The forks are a pair of L-shaped arms, one on each side, and are located in front of the backrest.

[0026] The tilt cylinder is a hydraulic cylinder used to tilt the mast in the forward and backward directions. For example, tilting the tilt lever forward extends the tilt cylinder and tilts the mast forward, while tilting the tilt lever backward retracts the tilt cylinder and tilts the mast backward. Returning the tilt lever to the neutral position (a position where the mast is neither tilted forward nor backward) stops the tilting of the mast.

[0027] The lift cylinder is a hydraulic cylinder used to raise and lower the mast. For example, tilting the lift lever forward causes the lift cylinder to retract and the inner mast to lower, while tilting the lift lever backward causes the lift cylinder to extend and the inner mast to rise. Returning the lift lever to the neutral position (neither tilted forward nor backward) stops the raising and lowering of the inner mast.

[0028] The control unit 4 controls the driving operation of the vehicle body 2 and the cargo handling operation of the cargo handling device 3. As shown in Figure 2, the control unit 4 comprises a vehicle control unit 4A, a cargo handling control mechanism 4B, a steering control mechanism 4C, and a driving control mechanism 4D.

[0029] The vehicle control unit 4A controls the driving and cargo handling operations by controlling the cargo handling control mechanism 4B, the steering control mechanism 4C, and the driving control mechanism 4D. The vehicle control unit 4A acquires detection signals necessary for controlling the driving and / or cargo handling operations from various sensors (excluding the sensor unit 5). Furthermore, the vehicle control unit 4A transmits and receives signals with the sensor unit 5. The vehicle control unit 4A is composed of, for example, an MPU and memory.

[0030] The cargo handling control mechanism 4B includes, for example, a cargo handling inverter, a cargo handling motor, a hydraulic circuit, etc. The vehicle control unit 4A acquires detection signals related to the amount of lever operation from the cargo handling levers (tilt lever and lift lever) and controls the cargo handling device 3 via the cargo handling control mechanism 4B.

[0031] The steering control mechanism 4C includes, for example, a steering motor, a power steering device, a hydraulic circuit, etc. The vehicle control unit 4A acquires detection signals regarding the direction and amount of rotation of the steering wheel and controls the rear wheels, which are the steering wheels, via the steering control mechanism 4C.

[0032] The driving control mechanism 4D includes, for example, a driving inverter, a driving motor, a hydraulic circuit, etc. The vehicle control unit 4A acquires detection signals related to the accelerator opening, brake state, and vehicle speed, etc., and controls the front wheels, which are the drive wheels, via the driving control mechanism 4D. As part of this control, the vehicle control unit 4A performs speed control to bring the driving speed of the vehicle body 2 closer to a predetermined target speed. Specifically, the vehicle control unit 4A acquires the driving speed of the vehicle body 2 based on the detection signal of the vehicle speed sensor, and calculates the target speed based on the detection signal of the accelerator sensor and / or the detection signal of the brake sensor. The vehicle control unit 4A performs PI control or PID control to bring the driving speed closer to the target speed. The target speed is calculated, for example, by the formula: Target speed = Set speed × Accelerator opening [%]. The set speed is a speed preset in the vehicle control unit 4A.

[0033] The sensor unit 5 is an area sensor that detects objects within a predetermined detection area. In this embodiment, a single 2D-LiDAR is used as the sensor unit 5. As shown in Figure 1, the sensor unit 5 (2D-LiDAR) is mounted on the upper part of the vehicle body 2 at an angle that allows it to irradiate laser light vertically upward relative to the road surface. Specifically, the sensor unit 5 is mounted on the upper part of the head guard and at the center in the left-right direction. The detectable area R of the sensor unit 5 is limited to the left-right center of the forklift 1 and is 180° or more in the front-rear direction (180° in Figure 1). If a 3D-LiDAR is used as the sensor unit 5, the detectable area R can be widened in the left-right direction according to the irradiation range of the laser light.

[0034] LiDAR can be classified into data output type and area setting type. Data output type LiDAR outputs distance information acquired from the reflected light of the laser beam for each laser beam irradiation angle. On the other hand, area setting type LiDAR outputs a detection signal when an object is detected in a set area. The sensor unit 5 in this embodiment is an area setting type 2D-LiDAR. As an area setting type 2D-LiDAR, for example, an area setting type range sensor manufactured by Hokuyo Electric Co., Ltd. can be used.

[0035] As shown in Figure 2, the sensor unit 5 comprises a sensor main circuit unit 5A, a sensor control unit 5B, a plurality of (five in this embodiment) input ports P1 to P5, and a plurality of (three in this embodiment) output ports P6 to P8.

[0036] The sensor main circuit section 5A includes a light-emitting section that emits laser light and a light-receiving section that receives reflected laser light. The sensor control section 5B includes a setting processing section that sets a detection area in the detectable area R and a drive processing section that drives the light-emitting section and the light-receiving section to detect an object in the detection area.

[0037] The configuration processing unit can simultaneously configure multiple detection areas (up to three in this embodiment) within the detectable area R. The configuration processing unit pre-stores up to three detection area patterns, associated with the input signals received at input ports P1 to P5. Details of the detection area patterns will be described later.

[0038] The drive processing unit outputs a first detection signal from output port P6 when it detects an object in the first detection area R1 (described later), outputs a second detection signal from output port P7 when it detects an object in the second detection area R2 (described later), and outputs a third detection signal from output port P8 when it detects an object in the third detection area R3 or the fourth detection area R4 (described later). The first to third detection signals are either on signals (high-level signals) or off signals (low-level signals). In the case of an off signal, for example, it will be high-level when no object is detected and low-level when an object is detected. As known technologies (e.g., TOF method) can be used for detecting objects using laser light, a detailed explanation will be omitted.

[0039] In this embodiment, input port P2 and output port P6 are connected by signal line L1, and input port P3 and output port P7 are connected by signal line L2. The first detection signal output from output port P6 is input to input port P2, and the second detection signal output from output port P7 is input to input port P3. This reduces the number of signal lines connecting the control unit 4 (vehicle control unit 4A) and the sensor unit 5, and reduces the number of signals output from the control unit 4 (vehicle control unit 4A) to the sensor unit 5.

[0040] The vehicle control unit 4A outputs a cargo handling operation signal to the sensor unit 5 when the cargo handling device 3 is lifting or lowering, and outputs a reverse signal when the vehicle body 2 is moving in reverse. The cargo handling operation signal is input to input port P4, and the reverse signal is input to input port P5. The cargo handling operation signal is, for example, a high level when the lift lever is in the forward or backward tilted position, and a low level when the lift lever is in the neutral position. The reverse signal is, for example, a high level when the vehicle body 2 is moving in reverse, and a low level when the vehicle body 2 is moving forward or stopped.

[0041] The detection area patterns for input signals input to input ports P1 to P5 are shown in Table 1. In Table 1, a circle (○) indicates the presence of an input signal, and a blank space indicates the absence of an input signal. Also, input port P1 is unused, and for input patterns other than patterns (1) to (14) in Table 1, no detection area is set.

[0042] [Table 1]

[0043] In patterns (1) to (4) and (11), the sensor unit 5 sets a detection area to determine the position of the upper end of the cargo handling device 3 (hereinafter referred to as the upper end position). In patterns (5) to (7), the sensor unit 5 is in a so-called self-holding state. In patterns (8) to (10), the sensor unit 5 sets a detection area to determine the presence or absence of an overhead obstacle C that could potentially collide. In patterns (12) to (14), the sensor unit 5 sets a detection area to determine the upper end position of the cargo handling device 3, and also sets a detection area to determine the presence or absence of an overhead obstacle C. Here, the upper end position of the cargo handling device 3 means the highest position among the position of the upper end of the mast, the position of the upper end of the backrest, and the position of the upper end of the load W held by the forks. Furthermore, in the following, the cargo handling device 3 includes the load W held by the cargo handling device 3.

[0044] In pattern (1), a cargo handling operation signal is input to input port P4. In this case, the sensor unit 5 sets the first detection area R1 and the second detection area R2 as detection areas, as shown in Figure 3(A). Pattern (1) is when a cargo handling operation is performed on the lifting and lowering of the cargo handling device 3, and the upper end position of the cargo handling device 3 (the upper end position of the mast) is below the second detection area R2.

[0045] The first detection area R1 includes the first area r1 located in front of the vehicle body 2 and above the cargo handling device 3 (more precisely, the cargo handling device 3 when the inner mast is not raised). The upper end of the first area r1 becomes the upper end of the first detection area R1, and the front end of the first area r1 becomes the front end of the first detection area R1. The second detection area R2 includes the second area r2 located in front of the vehicle body 2, above the cargo handling device 3 (more precisely, the cargo handling device 3 when the inner mast is not raised), and below the first area r1. The upper end of the second area r2 becomes the upper end of the second detection area R2, and the front end of the second area r2 becomes the front end of the second detection area R2.

[0046] The first area r1 and the second area r2 correspond to the height of the overhead obstacle C. For example, the height of the overhead obstacle C that may come into contact with the cargo handling device 3 when it is holding multiple loads W, or when the cargo handling device 3 has its inner mast raised, is measured in advance. The area where the overhead obstacle C is relatively tall is set as the first area r1, and the area where the overhead obstacle C is relatively short is set as the second area r2. In this embodiment, the first area r1 and the second area r2 are set in a rectangular shape, but their shape can be changed as appropriate.

[0047] In pattern (2), a second detection signal is input to input port P3, and a cargo handling operation signal is input to input port P4. In this case, the sensor unit 5 sets the first detection area R1 and the second detection area R2 as detection areas, as shown in Figure 3(B). The range of these detection areas is the same as in the case of Figure 3(A). Pattern (2) is when a cargo handling operation related to the lifting and lowering of the cargo handling device 3 is performed, and the upper end position of the cargo handling device 3 (the upper end position of the load W) is located in the second detection area R2.

[0048] In pattern (3), a first detection signal is input to input port P2, a second detection signal is input to input port P3, and a cargo handling operation signal is input to input port P4. In this case, the sensor unit 5 sets the first detection area R1 and the second detection area R2 as detection areas, as shown in Figure 3(C). The range of these detection areas is the same as in Figures 3(A) and (B). Pattern (3) is when a cargo handling operation is performed regarding the lifting and lowering of the cargo handling device 3, and the upper end position of the cargo handling device 3 (the upper end position of the load W) is located in the first detection area R1.

[0049] In pattern (4), the first detection signal is input to input port P2, and the cargo handling operation signal is input to input port P4. The second detection signal is not input to input port P3. In this case, the sensor unit 5 sets the first detection area R1 and the second detection area R2 as detection areas, as shown in Figure 3(C). When facing directly onto a shelf or depending on the shape of the cargo W (for example, when the cargo W is just the outer frame of a box), the case of pattern (4) may also occur.

[0050] In pattern (5), a second detection signal is input to input port P3. In this case, the sensor unit 5 sets the second detection area R2 as the detection area, as shown in Figure 4(A). Pattern (5) occurs when there is no lifting or lowering operation of the cargo handling device 3, the vehicle body 2 is stopped (or moving forward), and the upper end position of the cargo handling device 3 (the upper end position of the load W) is located in the second detection area R2.

[0051] In pattern (6), a first detection signal is input to input port P2 and a second detection signal is input to input port P3. In this case, the sensor unit 5 sets the first detection area R1 and the second detection area R2 as detection areas, as shown in Figure 4(B). The range of these detection areas is the same as in Figures 3(A) to (C). Pattern (6) is when there is no lifting or lowering operation of the cargo handling device 3, the vehicle body 2 is stopped (or moving forward), and the upper end position of the cargo handling device 3 (the upper end position of the load W) is in the first detection area R1.

[0052] In pattern (7), the first detection signal is input to input port P2, while the second detection signal is not input to input port P3. In this case, the sensor unit 5 sets the first detection area R1 and the second detection area R2 as detection areas, as shown in Figure 4(B).

[0053] In pattern (8), a second detection signal is input to input port P3 and a reverse signal is input to input port P5. In this case, the sensor unit 5 sets a second detection area R2 and a third detection area R3 (corresponding to the "third area" of the present invention) as detection areas, as shown in Figure 5(A). Pattern (8) is when the vehicle body 2 is moving in reverse and the upper end position of the cargo handling device 3 (the upper end position of the load W) is in the second detection area R2.

[0054] The third detection area R3 is a rectangular area, with its upper end set at the same position as the upper end of the second detection area R2 (or higher than the upper end of the second detection area R2), and its lower end set at the height of the sensor unit 5. The front end of the third detection area R3 is set in a position that does not detect the tilted cargo handling device 3, and the rear end of the third detection area R3 is set at the same position as the rear end of the vehicle body 2.

[0055] In pattern (9), a first detection signal is input to input port P2, a second detection signal is input to input port P3, and a reverse signal is input to input port P5. In this case, as shown in Figure 5(B), the sensor unit 5 sets the detection area to a first detection area R1, a second detection area R2, and a fourth detection area R4 (corresponding to the "fourth area" of the present invention). Pattern (9) is when the vehicle body 2 is moving in reverse and the upper end position of the cargo handling device 3 (the upper end position of the load W) is in the first detection area R1.

[0056] The fourth detection area R4 is a rectangular area, with its upper end set at the same position as the upper end of the first detection area R1 (or higher than the upper end of the first detection area R1), and its lower end set at the height of the sensor unit 5. The front end of the fourth detection area R4 is set in a position that does not detect the tilted cargo handling device 3, and the rear end of the fourth detection area R4 is set at the same position as the rear end of the vehicle body 2. In other words, the upper end position of the fourth detection area R4 is higher than the upper end position of the third detection area R3.

[0057] In pattern (10), the first detection signal is input to input port P2, and the reverse signal is input to input port P5. The second detection signal is not input to input port P3. In this case, the sensor unit 5 sets the detection area to the first detection area R1, the second detection area R2, and the fourth detection area R4, as shown in Figure 5(B).

[0058] In pattern (11), a cargo handling operation signal is input to input port P4 and a reverse signal is input to input port P5. In this case, the sensor unit 5 sets the first detection area R1 and the second detection area R2 as detection areas, as shown in Figure 3(A). Pattern (11) occurs during cargo handling operations related to the lifting and lowering of the cargo handling device 3, and when the vehicle body 2 is moving in reverse.

[0059] In pattern (12), a second detection signal is input to input port P3, a cargo handling operation signal is input to input port P4, and a reverse signal is input to input port P5. In this case, the sensor unit 5 sets the second detection area R2 and the third detection area R3 as detection areas, as shown in Figure 5(A). Pattern (12) occurs when cargo handling operations related to the lifting and lowering of the cargo handling device 3 are in operation, when the vehicle body 2 is moving in reverse, and when the upper end position of the cargo handling device 3 (the upper end position of the load W) is in the second detection area R2.

[0060] In pattern (13), a first detection signal is input to input port P2, a second detection signal is input to input port P3, a cargo handling operation signal is input to input port P4, and a reverse signal is input to input port P5. In this case, the sensor unit 5 sets the first detection area R1, the second detection area R2, and the fourth detection area R4 as detection areas, as shown in Figure 5(B). Pattern (13) occurs when cargo handling operations are performed on the lifting and lowering of the cargo handling device 3, when the vehicle body 2 is moving in reverse, and when the upper end position of the cargo handling device 3 (the upper end position of the load W) is in the first detection area R1.

[0061] In pattern (14), the first detection signal is input to input port P2, the cargo handling operation signal is input to input port P4, and the reverse signal is input to input port P5. The second detection signal is not input to input port P3. In this case, the sensor unit 5 sets the detection area to the first detection area R1, the second detection area R2, and the fourth detection area R4, as shown in Figure 5(B).

[0062] When the sensor unit 5 detects an object (upper obstacle C) in the third detection area R3 or the fourth detection area R4, it outputs a third detection signal from the output port P8. Upon receiving the third detection signal, the vehicle control unit 4A stops the vehicle body 2 from moving or limits the vehicle speed of the vehicle body 2 (for example, setting an upper speed limit of 4 [km / h]). This allows the forklift 1 to avoid contact with the upper obstacle C.

[0063] As described above, the forklift 1 sets up two detection areas (first detection area R1 and second detection area R2) to determine the upper end position of the cargo handling device 3, and sets up a detection area (third detection area R3 or fourth detection area R4) to determine the presence or absence of an overhead obstacle C depending on the upper end position of the cargo handling device 3. For example, if an overhead obstacle C is located at a height between the upper end of the third detection area R3 and the upper end of the fourth detection area R4, the forklift with the third detection area R3 set can pass under the overhead obstacle C without stopping or slowing down. Thus, the forklift 1 can avoid contact with the overhead obstacle C and suppress a decrease in work efficiency.

[0064] Forklift 1 has designated areas (third detection area R3, fourth detection area R4) where the vehicle body 2 stops moving or its speed is limited only when reversing, and the rear end of these areas is set to the same position as the rear end of the vehicle body 2. Therefore, frequent stopping or speed limitations when approaching walls or shelves within the work area can be avoided. In other words, with forklift 1, frequent stopping or speed limitations can be avoided in narrow loading and unloading work areas within the work area.

[0065] Note that in the state shown in Figure 3(A), forklift 1 detects the shelves in the first detection area R1 and the second detection area R2 when unloading. However, when forklift 1 reverses and moves away from the shelves, shelf detection ceases, and the input signals to input ports P2 and P3 are also eliminated, and the setting of the fourth detection area R4 is also eliminated. As a result, forklift 1 can pass under the upper obstacle C located in the fourth detection area R4 without stopping or slowing down.

[0066] In the case of forklift 1, most of the movement while holding the load W is in reverse. For this reason, in this embodiment, the third detection area R3 and the fourth detection area R4 detect the overhead obstacle C only when reversing using a reverse signal. However, even when a reverse signal is not used (input port P5 is not used), the detection areas can still be set. In that case, the pattern of the detection areas in response to the input signal is as shown in Table 2 below.

[0067] [Table 2]

[0068] Pattern (15) is the same as pattern (1), pattern (16) is the same as pattern (2), pattern (17) is the same as pattern (3), and pattern (18) is the same as pattern (4).

[0069] In pattern (19), a second detection signal is input to input port P3. In this case, the sensor unit 5 sets the second detection area R2 and the third detection area R3 as detection areas, as shown in Figure 5(A).

[0070] In pattern (20), the first detection signal is input to input port P2 and the second detection signal is input to input port P3. In this case, the sensor unit 5 sets the first detection area R1, the second detection area R2, and the fourth detection area R4 as detection areas, as shown in Figure 5(B).

[0071] In pattern (21), the first detection signal is input to input port P2, while the second detection signal is not input to input port P3. In this case, the sensor unit 5 sets the first detection area R1, the second detection area R2, and the fourth detection area R4 as detection areas, as shown in Figure 5(B).

[0072] When the sensor unit 5 detects an overhead obstacle C in the third detection area R3 or the fourth detection area R4, it outputs a third detection signal from the output port P8. Upon receiving the third detection signal, the vehicle control unit 4A either stops the vehicle body 2 from moving or limits the vehicle speed of the vehicle body 2 (for example, sets an upper speed limit of 4 km / h).

[0073] Furthermore, if the vehicle body 2 stops moving, the forklift 1 may enter a deadlock state. As a countermeasure, the forklift 1 may be provided with a release button to temporarily release the stop function. When the operator presses the release button, the stop function is temporarily released (for example, for a few minutes), allowing the deadlock state to be resolved during that time.

[0074] [Second Embodiment] Figure 6 shows a forklift 1' according to a second embodiment of the present invention. The forklift 1' of the second embodiment includes a control unit 4' and a sensor unit 5' instead of the control unit 4 and sensor unit 5. Except for the above, the forklift 1' has the same configuration as the forklift 1 of the first embodiment.

[0075] Figure 7 shows a block diagram of the control unit 4' and the sensor unit 5'. The control unit 4' and the sensor unit 5' have the same configuration as in the first embodiment, except that they are equipped with a signal line L1' that connects output port P6 to vehicle control unit 4A and a signal line L2' that connects output port P7 to vehicle control unit 4A.

[0076] The vehicle control unit 4A receives a first detection signal from the sensor unit 5' via signal line L1' and a second detection signal from the sensor unit 5' via signal line L2'. Also, similar to the first embodiment, the vehicle control unit 4A receives a third detection signal.

[0077] When a first detection signal is received, the vehicle control unit 4A limits the maximum speed of the vehicle body 2 when reversing to a first speed. If a first detection signal is not received but a second detection signal is received, the vehicle control unit 4A limits the maximum speed of the vehicle body 2 when reversing to a second speed. For example, the first speed is 2 km / h and the second speed is 4 km / h. These values ​​can be changed as appropriate. When a third detection signal is received, the vehicle control unit 4A stops the vehicle body 2 from moving or limits the vehicle speed of the vehicle body 2 (for example, to a maximum speed of 1 km / h), regardless of whether the first and second detection signals are received.

[0078] The length of the third detection area R3 and the fourth detection area R4 in the front-to-back direction is approximately 1 to 2 meters. Therefore, in the case of the forklift 1 of the first embodiment, if the vehicle speed is high just before detecting the overhead obstacle C in the third detection area R3 or the fourth detection area R4, it may not be possible to stop the vehicle body 2 from moving or to reduce the vehicle speed of the vehicle body 2 to the upper limit speed, and there is a risk that the cargo handling device 3 and the overhead obstacle C will come into contact.

[0079] In contrast, in the forklift 1' of the second embodiment, the vehicle control unit 4A constantly limits the vehicle speed of the vehicle body 2 when the first detection signal and / or the second detection signal are input. Therefore, the forklift 1' of the second embodiment can reliably avoid contact with the overhead obstacle C.

[0080] Although embodiments of the cargo handling vehicle according to the present invention have been described above, the present invention is not limited to the above embodiments.

[0081] The cargo handling vehicle according to the present invention comprises a vehicle body that travels within a predetermined work area, a cargo handling device provided on the front of the vehicle body that performs a lifting and lowering operation, a control unit that controls the travel and lifting and lowering operations, and a sensor unit that detects objects in a detection area above the vehicle body. The sensor unit, during lifting and lowering operations, sets a first area in the upper front of the vehicle body and a second area in the lower front of the vehicle body to detect the upper end of the cargo handling device. If the upper end is detected in the second area, during travel operations, it sets a third area behind the second area to detect an obstacle above the work area. If the upper end is detected in the first area, during travel operations, it sets a fourth area behind the first and second areas, higher than the third area, to detect an obstacle above. The control unit can be configured as appropriate to stop the vehicle or limit its speed if an obstacle above is detected in the third or fourth area.

[0082] The speed limit specified above can be set to any speed as long as it is lower than the vehicle's maximum speed when reversing.

[0083] Although the material handling vehicle of the present invention was described using a counterbalanced type forklift as an example in the above embodiment, it may also be a reach type forklift or another type of forklift. Furthermore, the material handling vehicle of the present invention is not limited to a forklift, and may be a vehicle other than a forklift (for example, a transport vehicle) as long as it is equipped with a material handling device capable of lifting and lowering. [Explanation of Symbols]

[0084] 1.1' Forklift 2. Vehicle body 3. Cargo handling equipment 4, 4' Control Unit 4A Vehicle Control Unit 4B Cargo handling control mechanism 4C Steering Control Mechanism 4D Driving Control Mechanism 5, 5' Sensor section 5A Sensor Main Circuit Section 5B Sensor Control Unit

Claims

1. A vehicle body that performs driving operations within a predetermined work area, A cargo handling device provided on the front side of the vehicle body that performs a lifting and lowering operation, A control unit that controls the aforementioned travel operation and the aforementioned lifting operation, A sensor unit that detects objects in a detection area above the vehicle body, A cargo handling vehicle equipped with, The aforementioned sensor unit is During the aforementioned lifting and lowering operation, a first area is set at the front upper level of the vehicle body and a second area is set at the front lower level of the vehicle body to detect the upper end of the cargo handling device. If the upper end is detected in the second area, a third area is set behind the second area during the driving operation to detect obstacles above the work area. If the upper end is detected in the first area, during the driving operation, a fourth area higher than the third area is set behind the first and second areas to detect the upper obstacle. If the control unit detects the overhead obstacle in the third or fourth area, it will stop the vehicle from moving or limit its speed. A cargo handling vehicle characterized by the following features.

2. The aforementioned sensor unit is The upper end position of the third area is set to be the same as or above the upper end position of the second area. The upper end position of the fourth area is set to be the same as or above the upper end position of the first area. The cargo handling vehicle according to feature 1.

3. The control unit outputs a cargo handling operation signal to the sensor unit during the lifting and lowering operation. The aforementioned sensor unit is If the cargo handling operation signal is not input and the upper end is detected in the second area, the second area is set without setting the first area. If the cargo handling operation signal is not input and the upper end is detected in the first area, the first area and the second area are set. The cargo handling vehicle according to feature 1.

4. The control unit outputs a reverse signal to the sensor unit when the vehicle body is moving in reverse. The aforementioned sensor unit is If the reverse signal is input and the upper end is detected in the second area, the second area and the third area are set. If the reverse signal is input and the upper end is detected in the first area, the first area, the second area, and the fourth area are set. The cargo handling vehicle according to feature 1.

5. The aforementioned sensor unit is When the cargo handling device is detected in the first area, a first detection signal is output. When the cargo handling device is detected in the second area, a second detection signal is output. When the overhead obstacle is detected in the third area or the fourth area, a third detection signal is output. The system includes signal lines that allow the outputted first detection signal and the second detection signal to be input to itself. The cargo handling vehicle according to feature 1.

6. The sensor unit outputs the first detection signal, the second detection signal, and the third detection signal to the control unit. The control unit, when the first detection signal or the second detection signal is input, limits the vehicle speed of the vehicle body. The cargo handling vehicle according to feature 5.

7. The control unit, When the first detection signal is input, the upper limit speed of the vehicle body when reversing is limited to the first speed. If the second detection signal is input but the first detection signal is not input, the upper limit speed is limited to a second speed greater than the first speed. The cargo handling vehicle according to feature 6.

Images