TRANSPORTING VEHICLE

Abstract

Task: To provide a handling vehicle that prevents contact with an overhead obstacle and can suppress a decrease in work efficiency. Means of solution: A handling vehicle 1, comprising a chassis 2, a handling device 3, a control unit 4 and a sensor unit 5, which performs a detection of objects above the chassis 2, is characterized in that, during lifting / lowering operation, the sensor unit 5 establishes the first area in front of the chassis 2 and performs a detection of the upper end of the handling device 3, and during driving operation, establishes the second area directly above the chassis 2 and establishes the third area behind the chassis 2 and performs a detection of an upper obstacle C in the working area if the upper end has been detected in the first area, and the control unit 4 stops the driving of the chassis 2 or limits the vehicle speed if an upper obstacle has been detected in the second area or the third area.

Description

Technical field

[0001] The present invention relates to a material handling vehicle such as a forklift. General state of the art

[0002] A conventional material handling vehicle is, for example, the vehicle described in patent literature 1. This material handling vehicle performs obstacle detection in the direction of travel. Specifically, it uses the detection result of an obstacle sensor, calculates a height H2 of the lifting frame based on the height of the obstacle sensor, calculates a first line connecting a position located a distance Lf from the obstacle sensor in the direction of travel, calculates a second line connecting a position located a height H2 away from the aforementioned position in the vertical direction, and calculates an angle θf formed by the first and second lines.The handling vehicle described in patent literature 1 prohibits travel or stops it when an obstacle is detected by the obstacle sensor in the area of ​​angle θf.

[0003] The material handling vehicle described in patent literature 1 also performs obstacle detection in the upward direction. Specifically, the material handling vehicle described in patent literature 1 uses the detection result of the obstacle sensor, calculates a first height H4 based on the height of the obstacle sensor, which is lower than the height to an obstacle located above the material handling vehicle, and calculates a second height H6 based on the height of the obstacle sensor, up to the top of the lifting mast. The material handling vehicle described in patent literature 1 prevents the lifting of the lifting mast or stops it if the second height H6 is equal to or greater than the first height H4.

[0004] The handling vehicle described in patent literature 1 can prevent contact with an overhead obstacle. However, since the handling vehicle described in patent literature 1 prohibits travel or stops when an obstacle is detected at a certain distance in front of the vehicle, travel is also prohibited or stopped when the vehicle approaches a wall or shelf in the work area. Therefore, in a confined work area, the handling vehicle described in patent literature 1 frequently stops, and work efficiency decreases significantly. Bibliography Patent literature

[0005] Patent literature 1: Patent disclosure 2021-111138 Brief description of the invention; Problem that the invention is intended to solve

[0006] The present invention was made in light of the circumstances described above and aims to provide a handling vehicle that prevents contact with an overhead obstacle and can suppress a decrease in work efficiency. Means of solving the problem

[0007] To solve the above problem, a material handling vehicle according to the present invention is required, which a chassis that performs a driving operation within a specific working area; a handling device that is formed on a front of the chassis and performs a lifting / lowering operation; a control unit that controls the driving operation and the lifting / lowering operation; and a sensor unit that performs a detection of objects in a first area, a second area and a third area above the chassis, characterized in that the sensor unit, during the lifting / lowering operation, establishes the first area in front of the chassis and detects the upper end of the handling device, and During operation, the second area is set up directly above the chassis and the third area is set up behind the chassis, and an upper obstacle is detected in the working area if the upper end has been detected in the first area, and the control unit The chassis stops moving or limits the vehicle speed if an upper obstacle is detected in the second or third area.

[0008] The above-described handling vehicle can be designed such that the sensor unit sets the position of the rear end of the second area at the same position as the position of the rear end of the chassis or in front of it, and sets the position of the upper end of the second area at the same position as the position of the upper end of the first area or above it.

[0009] The above-described handling vehicle can be designed such that the sensor unit establishes the position of the upper end of the third area above the position of the upper end of the second area, and establishes the position of the front end of the third area in front of the position of the rear end of the second area.

[0010] The above-described handling vehicle can be designed such that the control device outputs a handling operation signal to the sensor unit during a lifting / lowering operation, and the sensor unit The second and third areas are set up if no transshipment signal is entered and the upper end is detected in the first area.

[0011] The above-described handling vehicle can be designed such that the control unit sends a reverse signal to the sensor unit when the chassis is moving backwards, and the sensor unit The second and third areas are set up when the reverse signal is entered and the upper end is detected in the first area.

[0012] The above-described handling vehicle can be designed such that the sensor unit outputs a first detection signal when it detects the envelope device in the first area, outputs a second detection signal if it detects an upper obstacle in the second area, outputs a third detection signal when it detects an upper obstacle in the third area, and has a signal line to input the output first detection signal into itself.

[0013] The above-described handling vehicle can be designed such that the control unit limits the vehicle speed of the chassis when the upper end is detected in the first area during operation. Result of the invention

[0014] The present invention makes it possible to provide a handling vehicle that prevents contact with an overhead obstacle and can suppress a decrease in work efficiency. Brief description of the drawings Fig. Figure 1 shows a forklift truck according to a first embodiment, wherein (A) is a side view and (B) is a top view. Fig. Figure 2 is a block diagram of the sensor unit and the control unit according to the first embodiment. Fig. Figure 3 is a view showing the detection area during the lifting / lowering operation. Fig. Figure 4 is a view showing the detection range when the lifting / lowering operation is stopped and the vehicle is stationary. Fig. 5 is a view showing the detection area during driving operation (reverse driving). Fig. Figure 6 shows a forklift truck according to a second embodiment, wherein (A) is a side view and (B) is a top view. Fig. Figure 7 is a block diagram of the sensor unit and the control unit according to the second embodiment. The best embodiments of the invention

[0015] The following describes embodiments of the material handling vehicle according to the present invention with reference to the accompanying drawings. First embodiment

[0016] Fig. Figure 1 shows a forklift truck 1 according to a first embodiment of the present invention. The forklift truck 1 according to the first embodiment is a counterbalanced forklift truck and corresponds to the "handling vehicle" of the present invention. The forklift truck 1 performs a driving operation and a handling operation within a specific working area.

[0017] The work area is a space within any building, such as a factory or warehouse. Above the work area is an obstacle C (hereinafter referred to as "upper obstacle C"), such as a low ceiling, a door, or a projection. The work area also contains several shelves (not shown) on which cargo W and similar items are stored.

[0018] The forklift 1 has a chassis 2, a handling device 3, a control unit 4 and a sensor unit 5.

[0019] Chassis 2 is equipped with front and rear wheels on its underside and features a driver's seat and head guard on its upper surface. The front wheels are drive wheels powered by a drive motor, and the rear wheels are steered wheels steered (rotated) by a steering motor. The driver's seat is for the operator, and the head guard is a protective frame to shield the operator from falling objects.

[0020] Chassis 2 is equipped with an accelerator pedal and a brake at the foot of the driver's seat. The accelerator pedal is a pedal that the operator can operate from the driver's seat by pressing it with their foot. When the accelerator pedal is in the "on" state (the accelerator pedal is pressed), chassis 2 accelerates according to the degree of pedal depressurization (the degree of accelerator pedal release). When it switches from the "on" state to the "off" state (the accelerator pedal is not pressed), a weak regenerative braking effect is generated, which slows down chassis 2. The brake is a brake pedal that the operator can operate from the driver's seat by pressing it with their foot.When the brake is in the ON state (the brake pedal is depressed), a weaker regenerative braking effect is generated than with the regenerative braking of the accelerator pedal, thus slowing down the chassis 2, whereas no regenerative braking effect is generated when it is in the OFF state. The operator can initiate driving operations, such as accelerating or decelerating the chassis 2, by operating the accelerator pedal and / or the brake.

[0021] The chassis 2 has a steering wheel, a forward / reverse lever, and shift levers (a rocker lever and a 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. The operator can change the orientation (angle of rotation) of the rear wheels by turning the steering wheel in the direction of rotation of the steering wheel. The forward / reverse lever is located below the steering wheel and switches the driving mode of the chassis 2 between forward and reverse.If the operator moves the accelerator pedal to the ON position while the forward / reverse lever is in a forward-tilted position (in the forward position), the chassis 2 can be driven forward; and if the operator moves the accelerator pedal to the ON position while the forward / reverse lever is in a backward-tilted position (in the reverse position), the chassis 2 can be driven backward. The transfer levers are connected to the transfer device 3 via a transfer control mechanism 4B, which will be described later. The operator can initiate a transfer operation by actuating the transfer levers.

[0022] The handling device 3 comprises a lifting frame, a rear support and forks, a tilting cylinder and a lifting cylinder, and performs the handling operation. The handling operation includes raising / lowering the lifting frame and the forks.

[0023] The lifting mast is formed at the front of chassis 2 and raises and lowers the forks. The lifting mast has an outer mast and an inner mast. The outer mast has a pair of left and right guide rails running vertically and a crossbeam connecting the upper ends of the guide rails. The inner mast has a pair of left and right rails running vertically and a crossbeam (a coupling element) connecting the upper ends of the rails. The inner mast is formed on the inside of the outer mast's guide rails and moves up and down along the outer mast's guide rails. The outer mast does not move up and down.

[0024] The rear support is a frame body that prevents cargo W stacked on the forks from falling backward. A lifting beam is formed at its lower end. The lifting beam supports the forks and moves up and down along the lifting frame. That is, when the lifting frame (the inner mast) moves up and down, the rear support (including the lifting beam) and the forks also move up and down. The forks consist of a pair of left and right L-shaped arms and are formed on the front surface of the rear support.

[0025] The tilt cylinder is a hydraulic cylinder used to tilt the lifting frame in the forward and backward directions. For example, when the rocker arm is tilted forward, the tilt cylinder extends and tilts the lifting frame forward; conversely, when the rocker arm is tilted backward, the tilt cylinder retracts and tilts the lifting frame backward. When the rocker arm returns to its neutral position (the position in which it is neither tilted forward nor backward), the tilting of the lifting frame stops.

[0026] The lifting cylinder is a hydraulic cylinder used to raise and lower the lifting frame. For example, when the lifting lever is tilted forward, the lifting cylinder retracts and the inner mast moves downward; when the lifting lever is tilted backward, the lifting cylinder extends and the inner mast moves upward. When the lifting lever returns to its neutral position (the position in which it is neither tilted forward nor backward), the raising and lowering of the inner mast stops.

[0027] The control unit 4 controls the driving operation of the chassis 2 and the handling operation of the handling device 3. As in Fig. As shown in Figure 2, the control unit 4 includes a vehicle control unit 4A, the handling control mechanism 4B, the steering control mechanism 4C and a driving control mechanism 4D.

[0028] The vehicle control unit 4A controls both driving and handling operations by controlling the handling control mechanism 4B, the steering control mechanism 4C, and the driving control mechanism 4D. The vehicle control unit 4A receives detection signals from various sensors (except for sensor unit 5) that are necessary for controlling driving and handling operations. The vehicle control unit 4A also exchanges signals with sensor unit 5. The vehicle control unit 4A consists, for example, of a multi-processor unit (MPU), a memory, and similar components.

[0029] The handling control mechanism 4B includes, for example, a handling inverter, a handling motor, a hydraulic circuit, and the like. The vehicle control unit 4A receives detection signals from the handling levers (the rocker arm and the lifting lever) regarding the degree of actuation of the levers and controls the handling device 3 via the handling control mechanism 4B.

[0030] The steering control mechanism 4C includes, for example, a steering motor, a power steering device, a hydraulic circuit, and the like. The vehicle control unit 4A receives detection signals regarding the direction and extent of rotation of the steering wheel and controls the rear wheels, which are steered wheels, via the steering control mechanism 4C.

[0031] The vehicle control mechanism 4D includes, for example, a drive inverter, a drive motor, a hydraulic circuit, and the like. The vehicle control unit 4A receives detection signals regarding the degree of accelerator pedal depressor, the braking state, the vehicle speed, and the like, and controls the front wheels, which are the drive wheels, via the vehicle control mechanism 4D. For this control, the vehicle control unit 4A performs speed control to approximate the vehicle speed of the chassis 2 to a specific target speed. Specifically, the vehicle control unit 4A obtains the vehicle speed of the chassis 2 based on a detection signal from a vehicle speed sensor and calculates the target speed based on a detection signal from an accelerator pedal sensor and / or a detection signal from a brake sensor.The vehicle control unit 4A uses PI or PID control to approximate the vehicle speed to the target speed. The target speed is calculated, for example, using the formula "Target speed = Set speed × Accelerator pedal opening percentage [%]". The set speed is a speed that has been pre-set in the vehicle control unit 4A.

[0032] The sensor unit 5 is a range sensor that detects objects within a specific detection area. In the present embodiment, a single 2D LiDAR is used for the sensor unit 5. The sensor unit 5 (the 2D LiDAR) is as shown in Fig. The sensor unit 5 is mounted on the upper part of the chassis at an angle that allows it to emit laser light vertically upwards with respect to the driving surface. Specifically, the sensor unit 5 is mounted on the upper part of the head guard at a central position in the left-right direction. The detectable area R of the sensor unit 5 encompasses only the center in the left-right direction of the forklift 1 and at least 180° (180° in the present embodiment) in the forward-backward direction. If a 3D LiDAR is used for the sensor unit 5, the detectable area R can be given width in the left-right direction, depending on the emission range of the laser light.

[0033] A LiDAR can be classified into a data-output type and a range-detection type. A data-output LiDAR outputs distance information for each laser beam angle, derived from the reflected light of the laser beam. Conversely, a range-detection LiDAR outputs a detection signal when an object is detected within a defined area. The sensor unit 5 in the present embodiment is a 2D range-detection LiDAR. For example, a range-detection sensor from Hokuyô Denki Co., Ltd. can be used for the 2D range-detection LiDAR.

[0034] As in Fig. As shown in Figure 2, the sensor unit 5 has a sensor main circuit unit 5A, a sensor control unit 5B, several (five in the present embodiment) input terminals P1 to P5 and several (three in the present embodiment) output terminals P6 to P8.

[0035] The sensor main circuit unit 5A comprises a light projection unit that emits laser light and a light receiving unit that receives reflected light from the laser. The sensor control unit 5B comprises a setup processing unit that sets up the detection area within the detectable area R, and an operation processing unit that operates the projection unit and the light receiving unit to detect objects within the detection area.

[0036] The setup processing unit can simultaneously configure several detection areas (up to a maximum of three in the present embodiment) within the detectable area R. The setup processing unit stores predefined patterns of up to three detection areas in conjunction with input signals that were applied to input terminals P1 to P5. Details of the detection area patterns will be described later.

[0037] The operating processing unit outputs a first detection signal from the first output terminal P6 if an object is detected in a first detection area R1 (described later) among the three detection areas. It outputs a second detection signal from the second output terminal P7 if an object is detected in a second detection area R2 (described later). Finally, it outputs a third detection signal from the third output terminal P8 if an object is detected in a third detection area R3 (described later). The first through third detection signals are either an "on" signal (a signal with a high level) or an "off" signal (a signal with a low level). In the case of an "off" signal, it is at a high level when no object is detected and reaches a low level when an object is detected.Since a generally known technique (for example, the TOF method or the like) can be used for the method of detecting objects using laser light, an explanation is omitted here.

[0038] In the present embodiment, input terminal P2 and output terminal P6 are connected by a signal line L1. The first detection signal output from output terminal P6 is fed into input terminal P2. This reduces the number of signal lines connecting control unit 4 (vehicle control unit 4A) and sensor unit 5, and also reduces the number of signals output from control unit 4 (vehicle control unit 4A) to sensor unit 5.

[0039] The vehicle control unit 4A outputs a handling signal to the control unit 5 when the handling device 3 is in operation and a reverse signal when the chassis 2 is moving in reverse. The handling signal is input to input P4 and the reverse signal is input to input P5. For example, the handling signal is high when the lifting lever is in the forward or backward tilted position and low when it is in the neutral position. The reverse signal is high when the chassis 2 is moving in reverse and low when it is moving forward or when the vehicle is stopped.

[0040] The detection range patterns for the input signals applied to input terminals P1 to P5 are shown in Table 1 below. In Table 1, the presence of an input signal is indicated by ◯ and the absence of an input signal by an empty field. Input terminals P1 and P3 are not used, and no detection range is specified for input patterns other than patterns (1) to (8) in Table 1. Table 1 Muster P2 P4 P5 Detektionsbereich (1) ◯ Fig. 3(A) (2) ◯ ◯ Fig. 3(B) (3) Fig. 4(A) (4) ◯ Fig. 4(B) (5) ◯ Fig. 5(A) (6) ◯ ◯ Fig. 5(B) (7) ◯ ◯ Fig. 3(A) (8) ◯ ◯ ◯ Fig. 5(B)

[0041] In patterns (1), (2), and (7), the sensor unit 5 defines a detection range for recognizing the position of the upper end of the transfer device 3 (hereinafter referred to as the upper end position). In patterns (3) and (5), the sensor unit 5 does not define a detection range. In pattern (4), the sensor unit 5 is in the so-called self-holding state. In pattern (6), the sensor unit 5 defines a detection range for recognizing the presence or absence of an upper obstacle C that could potentially cause a collision. In pattern (8), the sensor unit 5 defines a detection range for recognizing the upper end position of the transfer device 3 and a detection range for recognizing the presence or absence of an upper obstacle C.Here, the upper end position means the highest position derived from the position of the upper end of the lifting frame, the position of the upper end of the rear support, and the position of the upper end of any cargo items W held on the forks. The handling device 3 also includes cargo items W held on the handling device 3.

[0042] In pattern (1), a switching operation signal is input into input port P4. In this case, the sensor unit 5 applies as shown Fig. Figure 3(A) shows the first detection area R1 as the detection area. Pattern (1) is a case in which the upper end position of the handling device 3 (the position of the upper end of the lifting frame) is below the first detection area R1 during the handling operation, which concerns the lifting / lowering operation of the handling device 3.

[0043] The first detection area R1 comprises a first area r1 in front of the chassis 2 and above the handling device 3 (more precisely, the handling device 3 in a state where 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 first detection area r1 corresponds to the height of an upper obstacle C. For example, the height of an upper obstacle C, which could potentially contact the handling device 3 in a state where it is holding several cargo items W, or the handling device 3 in a state where the inner mast has been raised, is measured in advance. The area where this upper obstacle C is present is defined as the first area r1.In the present embodiment, the first area r1 is defined as rectangular, but its shape can be changed as desired.

[0044] In pattern (2), the first detection signal is input into input terminal P2. In this case, the sensor unit 5 applies as shown in Fig. Figure 3(B) shows that the first detection area R1 is defined as the detection area. The extent of this detection area is the same as in Fig. 3(A). Pattern (2) is a case in which the upper end position of the handling device (the position of the upper end of the cargo pieces W) is located in the first detection area R1 during the handling operation which concerns the lifting / lowering operation of the handling device 3.

[0045] In pattern (3), no input signal is applied to input terminals P2, P4, P5. In this case, sensor unit 5 applies as shown. Fig. 4(A) shows no detection range defined. Pattern (3) is a case in which the handling device 3 is not in any lifting / lowering operation and the chassis 2 is stopped (or the chassis is moving forward) and the upper end position of the handling device 3 (the position of the upper end of the lifting frame) is below the first detection range R1. The sensor unit 5 does not need to store pattern (3) that does not define a detection range.

[0046] In pattern (4), the first detection signal is input into input terminal P2. In this case, the sensor unit 5 applies as shown in Fig. As shown in Figure 4(B), the first detection area R1 is defined as the detection area. The extent of this detection area is the same as in Figure 4(B). Fig. 3(A) and (B). Pattern (4) is a case in which there is no lifting / lowering operation of the handling device 3 and the movement of the chassis 2 is stopped (or the chassis is moving forward) and the upper end position of the handling device 3 (the position of the upper end of the cargo pieces W) is in the first detection area R1.

[0047] In pattern (5), the reverse signal is input into input terminal P5. In this case, sensor unit 5 applies as shown. Fig. Pattern (5) shows no detection range defined. Pattern (5) is a case in which the chassis 2 is reversing and the upper end position of the handling device 3 (the position of the upper end of the lifting frame) is below the first detection range R1. The sensor unit 5 does not need to store pattern (5) that does not define a detection range.

[0048] In pattern (6), the first detection signal is input to input terminal P2 and the reverse signal is input to input terminal P5. In this case, the sensor unit 5 applies as shown in Fig. Figure 5(B) shows the first detection area R1, the second detection area R2 (corresponding to the “second area” of the present invention), and the third detection area R3 (corresponding to the “third area” of the present invention) as detection areas. The model (6) is a case in which the chassis 2 is moving backward and the upper end position of the handling device 3 (the position of the upper end of the cargo pieces W) is located in the first detection area R1.

[0049] The second detection area R2 is a rectangular area positioned directly above the chassis 2. Its upper end is aligned with 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 is aligned with the height of the sensor unit 5. The front end of the second detection area R2 is positioned so that the rearward-tilting reversing device 3 is not detected, and the rear end of the second detection area R2 is aligned with the same position as the rear end of the chassis 2 (or further forward than the rear end of the chassis 2).

[0050] The third detection area R3 is a rectangular area positioned directly above and behind the chassis 2. Its upper end is positioned above the upper end of the second detection area R2 (or at the same position as the upper end of the second detection area R2), and its lower end is aligned with the height of the sensor unit 5. The front end of the third detection area R3 is positioned so that the rearward-tilting reversing device 3 is not detected (in Fig. 5(B) the same position as the front end of the second detection area R2). The rear end of the third detection area R3 is positioned further back than the rear end of chassis 2.

[0051] In example (7), the handling signal is input to input terminal P4 and the reverse signal is input to input terminal P5. In this case, the sensor unit 5 applies as shown in Fig. Figure 3(A) shows the first detection area R1 as the detection area. The pattern (7) is a case in which the upper end position of the chassis 3 (the position of the upper end of the lifting frame) is below the first detection area R1 during the handling operation, which concerns the lifting / lowering operation of the handling device 3, and during the reversing movement of the chassis 2.

[0052] In pattern (8), the first detection signal is input to input port P2, the reversing signal is input to input port P4, and the reverse signal is input to input port P5. In this case, the sensor unit 5 applies as shown in Fig. Figure 5(B) shows the first detection area R1, the second detection area R2, and the third detection area R3 as defined detection areas. Figure (8) is a case in which the upper end position of the handling device 3 (the position of the upper end of the cargo pieces W) is located in the first detection area R1 during the handling operation, which involves the lifting / lowering operation of the handling device 3, and during the reverse movement of the chassis 2.

[0053] If the sensor unit 5 detects an object (an upper obstacle C) in the second detection area R2, a second detection signal is output from the output terminal P7. The vehicle control unit 4A, into which the second detection signal was input, stops the movement of chassis 2 or limits the vehicle speed of chassis 2. When limiting the vehicle speed, the upper speed limit for reverse travel of chassis 2 is restricted to a first speed (for example, 2 [km / h]).

[0054] If the sensor unit 5 detects an object (an upper obstacle C) in the third detection area R3, a third detection signal is output from the output terminal P8. The vehicle control unit 4A, into which the third detection signal has been input, limits the vehicle speed of the chassis 2. This speed limit restricts the upper speed limit when the chassis 2 is reversing to a second speed that is higher than the first speed (for example, 4 km / h).

[0055] As described above, during the lifting / lowering operation of the handling device 3, the forklift 1 defines the first detection area R1 to detect the upper end position of the handling device 3. If the upper end position of the handling device 3 is detected in the first detection area R1, it defines the detection areas for detecting the presence or absence of an upper obstacle C (the second detection area R2 and the third detection area R3) when the chassis 2 is reversing. If the upper end position of the handling device 3 is not detected in the first detection area R1, the forklift 1 does not define the second detection area R2 or the third detection area R3. Therefore, the forklift 1 prevents contact with an upper obstacle C and suppresses a decrease in work efficiency.

[0056] Furthermore, the forklift 1 establishes an approximately two-stage detection zone above the chassis 2 and behind the handling device 3 (the second detection zone R2 and the third detection zone R3). Therefore, when reversing, the forklift 1 can gradually reduce its speed (or stop after reducing its speed) and reliably prevent contact with an obstacle above.

[0057] If the forklift 1 is in the state of Fig. 3(A), it can happen that when picking up cargo, a shelf is detected in the first detection area R1. However, since the detection of the shelf ends when the forklift 1 reverses and moves away from the shelf, the input signal to input terminal P2 (the first detection signal) disappears, and the determination of the second detection area R2 and the third detection area R3 also ends (resulting in the state of Fig. 5(A). This allows the forklift 1 to pass under an upper obstacle present in the second detection area R2 and / or the third detection area R3 without stopping or reducing its vehicle speed.

[0058] In the case of the forklift 1, travel while holding a load W is mostly in reverse. Therefore, in the present embodiment, a reverse signal is used, and the detection of an upper obstacle C in the second detection area R2 and the third detection area R3 is only performed during reverse travel. However, the detection area can also be defined in a case where no reverse signal is used (input terminal P5 is not used). In this case, the patterns of the detection areas with respect to the input signals are as shown in Table 2 below. Table 2 Muster P2 P4 Detektionsbereich (9) ◯ Fig. 3(A) (10) ◯ ◯ Fig. 3(B) (11) Fig. 5(A) (12) ◯ Fig. 5(B)

[0059] Pattern (9) is the same as pattern (1), and pattern (10) is the same as pattern (2).

[0060] In pattern (11), no input signal is applied to input terminals P2, P4. In this case, the sensor unit 5 applies the following as shown. Fig. 4(A) and Fig. 5(A) does not define a detection range. The sensor unit 5 does not need to store the pattern (11) that does not define a detection range.

[0061] In pattern (12), the first detection signal is input into input terminal P2. In this case, the sensor unit defines the first detection range R1, the second detection range R2, and the third detection range R3 as detection ranges.

[0062] If the sensor unit 5 detects an upper obstacle C in the third detection area R3, the vehicle control unit 4A limits the vehicle speed of the chassis 2. If the sensor unit 5 detects an upper obstacle C in the second detection area R2, the vehicle control unit 4A stops the movement of the chassis 2 or limits the vehicle speed of the chassis 2.

[0063] When the movement of chassis 2 is stopped, there is a risk that the forklift 1 will enter a deadlock state. As a preventative measure, the forklift 1 can be equipped with a release button that temporarily disengages the stop. Since the stop is only temporarily lifted (for example, for a few minutes) when the operator presses the release button, this deadlock state can be resolved during this time. Second embodiment

[0064] Fig. Figure 6 shows a forklift 1' according to a second embodiment of the present invention. The forklift 1' of the second embodiment has a control unit 4' and a sensor unit 5' instead of the control unit 4 and the sensor unit 5. With the exception of the above point, the forklift 1' has the same construction as the forklift 1 of the first embodiment.

[0065] Fig. 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' are constructed as in the first embodiment, except that a signal line L' is provided which connects the output terminal P6 and the vehicle control unit 4A.

[0066] The first detection signal from sensor unit 5' is fed into vehicle control unit 4 via signal line L1'. Vehicle control unit 4A, having received the first detection signal, imposes a speed limit on chassis 2. This speed limit restricts the upper speed limit for reverse travel of chassis 2 to a third speed, which is higher than the second speed (for example, 6 km / h).

[0067] If, for example, the chassis 2 of the forklift 1 of the first embodiment is traveling in reverse at maximum speed at a time when the sensor unit 5 has detected an upper obstacle C in the third detection area R3, there is a risk that the vehicle control unit 4A will not be able to slow the chassis 2 down to the second speed (for example, 4 km / h). Therefore, in the forklift 1 of the first embodiment, it is necessary to ensure a certain distance (sufficient to allow a reduction from maximum speed to the second speed) between the rear end of the third detection area R3 and the rear end of the second detection area R2.

[0068] In contrast, in the second embodiment, the vehicle speed of the chassis 2 is always limited when the upper end position of the handling device 3 is detected in the first detection area R1. Therefore, this distance can be shortened in the forklift 1' of the second embodiment, and the position of the rear end of the third detection area R3 can be brought closer to the position of the rear end of the second detection area R2. As a result, the number of vehicle speed limitations can be reduced to the second speed limit.

[0069] Above, embodiments of the handling vehicle of the present invention have been explained, but the present invention is not limited to the embodiments described above.

[0070] Provided that the handling vehicle according to the present invention is a handling vehicle comprising a chassis that performs a driving operation in a specific working area; a handling device that is formed on a front of the chassis and performs a lifting / lowering operation; a control unit that controls the driving operation and the lifting / lowering operation;and a sensor unit that detects objects in a first area, a second area, and a third area above the chassis, wherein, during lifting / lowering operation, the sensor unit establishes the first area in front of the chassis and detects the upper end of the handling device, and during driving operation, establishes the second area directly above the chassis and establishes the third area behind the chassis and detects an upper obstacle in the working area if the upper end has been detected in the first area, and the control unit stops the movement of the chassis or limits the vehicle speed if an upper obstacle has been detected in the second area or the third area, the setup can be modified as desired.

[0071] The speed limit for the vehicle speed mentioned above can be set to any speed as long as it is lower than the maximum speed when the chassis is moving in reverse.

[0072] The handling vehicle of the present invention has been described in the above embodiments using a counterbalance forklift, but it can also be a reach truck or another type of forklift. Furthermore, the handling vehicle of the present invention is not limited to a forklift, but can also be a vehicle other than a forklift (for example, a transport vehicle), as long as it is equipped with a handling device capable of lifting / lowering. Reference symbol list 1, 1' forklift 2 chassis 3 Handling device 4, 4' control unit 4A Vehicle Control Unit 4B Transaction control mechanism 4C Steering Control Mechanism 4D driving control mechanism 5.5' Sensor unit 5A Sensor Main Circuit Unit 5B Sensor control unit

Claims

Handling vehicle, wherein the handling vehicle comprises a chassis that performs a driving operation within a specific working area; a handling device formed on a front of the chassis that performs a lifting / lowering operation; a control unit that controls the driving operation and the lifting / lowering operation;and a sensor unit that performs object detection in a first area, a second area, and a third area above the chassis, characterized in that, during lifting / lowering operation, the sensor unit establishes the first area in front of the chassis and detects the upper end of the handling device, and during driving operation, establishes the second area directly above the chassis and establishes the third area behind the chassis and detects an upper obstacle in the working area if the upper end has been detected in the first area, and the control unit stops the movement of the chassis or limits the vehicle speed if an upper obstacle has been detected in the second area or the third area. Handling vehicle according to claim 1, characterized in that the sensor unit sets the position of the rear end of the second area at the same position as the position of the rear end of the chassis or in front of it, and sets the position of the upper end of the second area at the same position as the position of the upper end of the first area or above it. Handling vehicle according to claim 2, characterized in that the sensor unit sets the position of the upper end of the third area above the position of the upper end of the second area, and sets the position of the front end of the third area in front of the position of the rear end of the second area. Handling vehicle according to claim 1, characterized in that the control device outputs a handling operation signal to the sensor unit during a lifting / lowering operation, and the sensor unit sets up the second area and the third area when no handling operation signal is input and the upper end is detected in the first area. Handling vehicle according to claim 1, characterized in that the control unit outputs a reverse driving signal to the sensor unit when the chassis is in reverse, and the sensor unit sets up the second area and the third area when the reverse driving signal is input and the upper end is detected in the first area. Handling vehicle according to claim 1, characterized in that the sensor unit outputs a first detection signal when it detects the handling device in the first area, outputs a second detection signal when it detects an upper obstacle in the second area, outputs a third detection signal when it detects an upper obstacle in the third area, and has a signal line to input the output first detection signal into itself. Handling vehicle according to claim 1, characterized in that the control unit limits the vehicle speed of the chassis when the upper end is detected in the first area during driving operation.

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