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 up two upper and lower first and second areas in front of the vehicle body 2 to detect the upper end of the cargo handling device 3, and if the upper end is detected in the first area, during driving operations, sets up a third area directly above the vehicle body 2 to detect an overhead obstacle C, and if the upper end is detected in the second area, during driving operations, sets up a fourth area directly above the vehicle body 2 that is lower than the third area, and sets up a fifth area behind the vehicle body 2 that is lower than the third area to detect an overhead obstacle C, and the control unit 4, when an overhead obstacle C is detected in the third area, fourth area, or fifth area, stops the vehicle body 2 from moving or limits the vehicle speed.

Description

Technical Field

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

Background Art

[0002] As a conventional cargo handling vehicle, for example, the one described in Patent Document 1 is known. The cargo handling vehicle described in Patent Document 1 detects obstacles in the traveling direction. Specifically, the cargo 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 that is at a first distance Lf from the obstacle sensor in the traveling direction and the obstacle sensor, calculates a second line connecting the position that is 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 cargo handling vehicle described in Patent Document 1 prohibits or stops traveling.

[0003] In addition, the cargo handling vehicle described in Patent Document 1 also detects an upper obstacle. Specifically, the cargo handling vehicle described in Patent Document 1 calculates a first height H4 that is lower than the height to an obstacle above the cargo 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 equal to or greater than the first height H4, the cargo handling vehicle described in Patent Document 1 prohibits or stops the raising of the mast.

[0004] The cargo handling vehicle described in Patent Document 1 can avoid contact with an upper obstacle. However, in the detection of an obstacle in the traveling direction, since the cargo handling vehicle described in Patent Document 1 detects an obstacle at a certain distance ahead and prohibits or stops traveling, it also prohibits or stops traveling when approaching a wall or a shelf in the work area. As a result, in a narrow cargo handling work site, traveling prohibition or traveling stop frequently occurs in the cargo 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 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 first area, a third area is set directly above the vehicle body during the driving operation to detect obstacles above the work area. If the upper end is detected in the second area, during the driving operation, a fourth area lower than the third area is set directly above the vehicle body, and a fifth area lower than the third area is set behind the vehicle body to detect the overhead obstacle. The control unit is characterized in that, when the overhead obstacle is detected in the third area, the fourth area, or the fifth area, it stops the vehicle from moving or limits the vehicle speed.

[0008] In the aforementioned cargo handling vehicle, The control unit, If the upper end is detected in the first area during the aforementioned driving operation, the vehicle speed of the vehicle body is always limited, If the upper end is detected in the second area during the aforementioned driving operation, the vehicle speed limit of the vehicle body can be configured not to be applied until the upper obstacle is detected in the fourth area or the fifth area.

[0009] In the aforementioned cargo handling vehicle, The aforementioned sensor unit is If the upper end of the first area is detected during the lifting operation, the setting of the second area can be canceled during the travel operation, and the lower end of the first area can be extended to the lower end position of the second area.

[0010] 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 first area. The upper end position of the fourth area is set to be the same as or above the upper end position of the second area. The upper end position of the fifth area is set to be the same as or above the upper end position of the second area. The front end position of the fifth area can be configured to be set further forward than the rear end position of the fourth area.

[0011] 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 first area, the third area is set without setting the second area. If the cargo handling operation signal is not input and the upper end is detected in the second area, the system can be configured to set the fourth and fifth areas without setting the first area.

[0012] In the above-mentioned work vehicle, When the vehicle body is moving backward, the control unit outputs a backward signal to the sensor unit. The sensor unit When the backward signal is input and the upper end is detected in the first area, the third area is set without setting the second area. When the backward signal is input and the upper end is detected in the second area, the fourth area and the fifth area can be configured to be set without setting the first area.

[0013] In the above-mentioned work vehicle, The sensor unit When detecting the cargo handling device in the first area or detecting the upper obstacle in the fifth area, a first detection signal is output. When detecting the cargo handling device in the second area, a second detection signal is output. When detecting the upper obstacle in the third area or the fourth area, a third detection signal is output. It can be configured to include signal lines for inputting the output first detection signal and the second detection signal to itself.

Advantages of the Invention

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

Brief Description of the Drawings

[0015] [Figure 1] The forklift of the present invention, (A) is a side view, and (B) is a plan view. [Figure 2] It is a block diagram of the sensor unit and the control unit according to the present invention. [Figure 3] It is a diagram showing a detection area during lifting and lowering operations. [Figure 4] This diagram shows the detection area when the lifting operation is stopped and the vehicle is stopped moving. [Figure 5] This diagram shows the detection area during driving (reverse). [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] Figure 1 shows a forklift 1 according to one embodiment of the present invention. Forklift 1 is a counterbalanced type forklift and corresponds to the "cargo handling vehicle" of the present invention. 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 or the fifth detection area R5, as described later, outputs a second detection signal from output port P7 when it detects an object in the second detection area R2, as 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, as 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, the input port P2 and the output port P6 are connected by a signal line L1. The first detection signal output from the output port P6 is input to the input port P2. 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. In addition, since the signal line L1' branched from the signal line L1 is connected to the vehicle control unit 4A, the first detection signal is also input to the vehicle control unit 4A.

[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 (16) in Table 1, no detection area is set.

[0042] [Table 1]

[0043] In patterns (1) to (4) and (13), 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) and (9), the sensor unit 5 does not set a detection area. In patterns (6) and (8), the sensor unit 5 is in a so-called self-holding state. In patterns (10) to (12) and (16), the sensor unit 5 sets a detection area to determine the presence or absence of an overhead obstacle C that could potentially collide. Patterns (7), (14), and (15) occur instantaneously when switching between patterns. 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, below, 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, and no input signals are input to input ports P2, P3, and 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 (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, a cargo handling operation signal is input to input port P4, and no input signals are input to input ports P2 and 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(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 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 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, a cargo handling operation signal is input to input port P4, and no input 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(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 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 first detection area R1.

[0049] In pattern (4), the first detection signal is input to input port P2, the cargo handling operation signal is input to input port P4, and no input signals are input to input ports P3 and 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(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), no input signals are input to input ports P2 to P5. In this case, the sensor unit 5 does not set a 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 mast) is below the second detection area R2. Note that the sensor unit 5 does not need to store the pattern (5) in which no detection area is set.

[0051] In pattern (6), a second detection signal is input to input port P3, and no input signals are input to input ports P2, P4, and P5. In this case, the sensor unit 5 sets the second detection area R2 as the detection area, as shown in Figure 4(B). Pattern (6) 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.

[0052] In pattern (7), the first detection signal is input to input port P2, the second detection signal is input to input port P3, and no input signals are input to input ports P4 and P5. Pattern (7) is the case where, in the state of pattern (3), the input of the cargo handling operation signal to input port P4 is stopped, and it immediately transitions to pattern (8). The detection area transitions from the state in Figure 3(C) to the state in Figure 4(C).

[0053] In pattern (8), the first detection signal is input to input port P2, and no input signals are input to input ports P3 to P5. In this case, the sensor unit 5 sets the first detection area R1 as the detection area, as shown in Figure 4(C). Pattern (8) 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 in the first detection area R1.

[0054] However, the first detection area R1 of pattern (8) 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 area of ​​the first area r1' is the same as the areas of the first area r1 and the second area r2.

[0055] In pattern (9), a reverse signal is input to input port P5, and no input signals are input to input ports P2 to P4. In this case, the sensor unit 5 does not set a detection area, as shown in Figure 5(A). Pattern (9) occurs 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 mast) is below the first detection area R1 and the second detection area R2. Note that the sensor unit 5 does not need to store pattern (9), in which no detection area is set.

[0056] In pattern (10), a second detection signal is input to input port P3, a reverse signal is input to input port P5, and no input signals are input to input ports P2 and P4. In this case, as shown in Figure 5(B), the sensor unit 5 sets the second detection area R2, the fourth detection area R4 (corresponding to the "fourth area" of the present invention), and the fifth detection area R5 (corresponding to the "fifth area" of the present invention) as detection areas. Pattern (10) 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.

[0057] In pattern (11), the first detection signal is input to input port P2, the second detection signal is input to input port P3, the reverse signal is input to input port P5, and no input signal is input to input port P4. In this case, the sensor unit 5 sets the second detection area R2, the fourth detection area R4, and the fifth detection area R5 as detection areas, as shown in Figure 5(B). Pattern (11) is, for example, the case when an overhead obstacle C is detected in the fifth detection area R5.

[0058] In pattern (12), a first detection signal is input to input port P2, a reverse signal is input to input port P5, and no input signals are input to input ports P3 and P4. In this case, the sensor unit 5 sets a first detection area R1 and a third detection area R3 (corresponding to the "third area" of the present invention) as detection areas, as shown in Figure 5(C). The first detection area R1 is the same as the first detection area R1 of pattern (8) shown in Figure 4(C). Pattern (12) 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 upper part of the first detection area R1 (the area of ​​the first area r1).

[0059] The third detection area R3 is a rectangular area located directly above the vehicle body 2, 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 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 or near the rear end of the vehicle body 2.

[0060] The fourth detection area R4 is a rectangular area located directly above the vehicle body 2. Its upper end is at the same position as the upper end of the second detection area R2 (or above the upper end of the second detection area R2 and below the upper end of the first detection area R1), and its lower end is 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 or near the rear end of the vehicle body 2.

[0061] The fifth detection area R5 is a rectangular area located directly above and behind the vehicle body 2. Its upper end is set above (or at the same position as) the upper end of the second detection area R2, and its lower end is set at the height of the sensor unit 5. The front end of the fifth detection area R5 is set in a position that does not detect the tilted cargo handling device 3, and the rear end of the fifth detection area R5 is set behind the rear end of the vehicle body 2.

[0062] In pattern (13), a cargo handling operation signal is input to input port P4, a reverse signal is input to input port P5, and no input signals are input to input ports P2 and 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(A). Pattern (11) is when a cargo handling operation related to the lifting and lowering of the cargo handling device 3 is performed and the vehicle body 2 is moving in reverse, and the upper end position of the cargo handling device 3 is below the second detection area R2.

[0063] In pattern (14), a second detection signal is input to input port P3, a cargo handling operation signal is input to input port P4, a reverse signal is input to input port P5, and no input signal is input to input port P2. Pattern (14) occurs, for example, when a second detection signal is input to input port P3 in the state of pattern (13) (for example, when the upper end position of the cargo handling device 3 is detected in the second detection area R2 due to a cargo handling operation), and immediately transitions to pattern (16). The detection area transitions from the state in Figure 3(A) to the state in Figure 5(C).

[0064] In pattern (15), 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. Pattern (15) occurs, for example, when, in the state of pattern (13), a first detection signal is input to input port P2 and a second detection signal is input to input port P3 (for example, when the upper end position of the cargo handling device 3 is detected in the first detection area R1 due to a cargo handling operation), and immediately transitions to pattern (16). The detection area transitions from the state in Figure 3(A) to the state in Figure 5(C).

[0065] In pattern (16), a first detection signal is input to input port P2, a cargo handling operation signal is input to input port P4, a reverse signal is input to input port P5, and no input signal is input to input port P3. In this case, the sensor unit 5 sets the first detection area R1 and the third detection area R3 as detection areas, as shown in Figure 5(C).

[0066] The reason for the transition from pattern (14) or pattern (15) to pattern (16) is that, in this embodiment, it is not possible to set the detection area shown in Figure 3(A) and the detection area shown in Figure 5(B) simultaneously. That is, if the upper end position of the cargo handling device 3 is detected in the first detection area R1 or the second detection area R2 while in the state of pattern (13), the detection area shown in Figure 5(C) is set for safety reasons.

[0067] When the sensor unit 5 detects an object (cargo handling device 3) in the first detection area R1, or when it detects an object (upper obstacle C) in the fifth detection area R5, it outputs a first detection signal from the output port P6. Upon receiving the first detection signal, the vehicle control unit 4A limits the vehicle speed of the vehicle body 2. This speed limit restricts the upper limit speed of the vehicle body 2 when reversing to a first speed (for example, 4 km / h).

[0068] 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. With this speed limit, the upper limit speed of the vehicle body 2 when moving in reverse is restricted to a second speed (for example, 1 km / h) which is lower than the first speed.

[0069] As described above, 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 and fifth detection area R5) 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 fifth detection area R5, a forklift with fourth detection area R4 and fifth detection area R5 set up can pass under the overhead obstacle C without stopping or slowing down. Thus, with forklift 1, contact with the overhead obstacle C can be avoided and a decrease in work efficiency can be suppressed.

[0070] When forklift 1 detects the upper end position of the cargo handling device 3 in the first detection area R1 during cargo handling operations, it sets a third detection area R3 to detect an overhead obstacle C when reversing and constantly limits the vehicle speed. Therefore, when forklift 1 detects an overhead obstacle C in the third detection area R3, it can reliably decelerate to the second speed or stop moving.

[0071] When the forklift 1 detects the upper end position of the cargo handling device 3 in the second detection area R2 during cargo handling operations, it sets up two detection areas (fourth detection area R4 and fifth detection area R5) behind the second detection area R2 when reversing. As a result, the forklift 1 can perform gradual deceleration (or stop driving after the vehicle speed limit is reached) when reversing, and can reliably avoid contact with the overhead obstacle C.

[0072] Note that in the state shown in Figure 3(A), forklift 1 detects the shelf in the first detection area R1 and the second detection area R2 when unloading. However, when forklift 1 reverses and moves away from the shelf, the shelf detection ceases, and the input signals to input ports P2 and P3 also cease, and the detection areas that determine the presence or absence of an overhead obstacle C (third detection area R3, or fourth detection area R4 and fifth detection area R5) also disappear. As a result, forklift 1 can pass under the overhead obstacle C located in the above detection areas without stopping or slowing down.

[0073] However, if the upper end of the cargo handling device 3 (the upper end of the load W) is located in the second detection area R2 when unloading, and a shelf is detected in the first detection area R1, even if the forklift 1 reverses and moves away from the shelf, the range of the detection area will follow the pattern shown in Figure 4(C). Therefore, the detection area used to determine the presence or absence of an overhead obstacle C when the forklift 1 is reversing will be the third detection area R3 (Figure 5(C)), which is higher than the upper end of the cargo handling device 3. As a result, the forklift will stop or slow down below the overhead obstacle C, which it should be able to pass.

[0074] 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 detection of the overhead obstacle C is performed only when reversing using the reverse signal. However, even when the reverse signal is not used (input port P5 is not used), the detection area can still be set. In that case, the pattern of the detection area in relation to the input signal is as shown in Table 2 below.

[0075] [Table 2]

[0076] Pattern (17) is the same as pattern (1), pattern (18) is the same as pattern (2), pattern (19) is the same as pattern (3), and pattern (20) is the same as pattern (4).

[0077] In pattern (21), the second detection signal is input to input port P3, and no input signals are input to input ports P2 and P4. In this case, the sensor unit 5 sets the second detection area R2, the fourth detection area R4, and the fifth detection area R5 as detection areas, as shown in Figure 5(B).

[0078] In pattern (22), the first detection signal is input to input port P2, the second detection signal is input to input port P3, and no input signal is input to input port P4. In this case, the sensor unit 5 sets the second detection area R2, the fourth detection area R4, and the fifth detection area R5 as detection areas, as shown in Figure 5(B). Pattern (22) is, for example, the case when an overhead obstacle C is detected in the fifth detection area R5.

[0079] In pattern (23), the first detection signal is input to input port P2, and no input signals are input to input ports P3 and P4. In this case, the sensor unit 5 sets the first detection area R1 and the third detection area R3 as detection areas, as shown in Figure 5(C).

[0080] When the sensor unit 5 detects an object (cargo handling device 3) in the first detection area R1, or when it detects an object (upper obstacle C) in the fifth detection area R5, it outputs a first detection signal from the output port P6. Upon receiving the first detection signal, the vehicle control unit 4A limits the vehicle speed of the vehicle body 2. This speed limit restricts the upper limit speed of the vehicle body 2 when reversing to a first speed (for example, 4 km / h).

[0081] 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 body 2's speed. With this speed limit, the upper limit speed of the vehicle body 2 when moving in reverse is restricted to a second speed (for example, 1 km / h).

[0082] 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.

[0083] 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.

[0084] 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 first area, during travel operations, it sets a third area directly above the vehicle body to detect an obstacle above the work area. If the upper end is detected in the second area, during travel operations, it sets a fourth area directly above the vehicle body that is lower than the third area, and a fifth area behind the vehicle body that is lower 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, fourth, or fifth area.

[0085] 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.

[0086] 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]

[0087] 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 first area, a third area is set directly above the vehicle body during the driving operation to detect obstacles above the work area. If the upper end is detected in the second area, during the driving operation, a fourth area lower than the third area is set directly above the vehicle body, and a fifth area lower than the third area is set behind the vehicle body to detect the overhead obstacle. If the control unit detects the overhead obstacle in the third area, the fourth area, or the fifth area, it will stop the vehicle from moving or limit its speed. A cargo handling vehicle characterized by the following features.

2. The control unit, If the upper end is detected in the first area during the aforementioned driving operation, the vehicle speed of the vehicle body is always limited, If the upper end is detected in the second area during the aforementioned driving operation, the vehicle speed limit of the vehicle body will not be applied until the upper obstacle is detected in the fourth area or the fifth area. The cargo handling vehicle according to feature 1.

3. The aforementioned sensor unit is If the upper end of the first area is detected during the lifting operation, the setting of the second area is canceled during the travel operation, and the lower end of the first area is extended to the lower end position of the second area. The cargo handling vehicle according to feature 1.

4. 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 first area. The upper end position of the fourth area is set to be the same as or above the upper end position of the second area. The upper end position of the fifth area is set to be the same as or above the upper end position of the second area. The front end position of the fifth area is set forward of the rear end position of the fourth area. The cargo handling vehicle according to feature 1.

5. 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 first area, the third area is set without setting the second area. If the cargo handling operation signal is not input and the upper end is detected in the second area, the fourth and fifth areas are set without setting the first area. The cargo handling vehicle according to feature 1.

6. 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 first area, the third area is set without setting the second area. If the reverse signal is input and the upper end is detected in the second area, the fourth and fifth areas are set without setting the first area. The cargo handling vehicle according to feature 5.

7. The aforementioned sensor unit is When the cargo handling device is detected in the first area, or when the overhead obstacle is detected in the fifth 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.

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