WARNING SYSTEM AND FORKLIFT

Abstract

Means of solution: The warning system, comprising a forklift 1A and a warning unit 2, is characterized in that the forklift 1A has a sensor unit 30, which measures the weight load on the forks 23, the travel speed, and the rotation angle of the rear wheels 12, a first control unit 40, and a second control unit 50, wherein the second control unit 50 performs a first determination process, in which it is determined that a claw retraction operation by the forks 23 occurs when a reverse travel distance of the chassis 10 from a time at which the weight load has changed to a state of less than a first threshold value is within a certain first distance, and a first detection process, in which it is detected that a first hazardous action has occurred when the rotation angle during the claw retraction operation is at least a certain first angle.and the warning unit 2 issues a warning when the second control unit 50 has detected that the first hazardous action has occurred.

Description

Technical field

[0001] The present invention relates to a warning system and a forklift truck. General state of the art

[0002] A conventional operational management system for managing the operational status of a forklift truck is known. For example, a forklift operational management system consists of a forklift truck equipped with a data logger unit (hereinafter referred to as DLU), a server that is communicatively connected to the DLU, and a management device that is communicatively connected to the server.

[0003] The DLU can store not only the forklift's operating status but also any hazardous actions performed by the forklift on the server. Therefore, an administrator of the forklift operations management system can access the server via the management device and check the forklift's operating status and any hazardous actions.

[0004] On the other hand, the forklift warns the operator of a hazardous situation by means of a buzzer or a warning light. For example, if there is a step on the driving surface, a warning light mounted on the driver's seat dashboard will be illuminated or a buzzer will be emitted on the forklift described in patent literature 1 to inform the operator that a step is nearby. Bibliography Patent literature

[0005] Patent literature 1: Patent disclosure no. H09-272700 Brief description of the invention; Problem that the invention is intended to solve

[0006] Hazardous actions of the forklift include not only driving on a surface with a step, but also various other actions (for example, turning while retracting the forks or turning while picking up a load). However, if, as with the forklift described in patent literature 1, the only warning devices are a buzzer and a warning light, the operator may not be able to immediately assess what type of hazardous action has been detected. Consequently, with the forklift described in patent literature 1, a hazardous action cannot be suppressed.

[0007] The present invention was made in light of these circumstances and aims to provide a warning system that allows the operator to easily assess dangerous actions and a forklift truck that can suppress these dangerous actions. Means of solving the problem

[0008] To solve the above problem, a warning system according to the present invention is required, which a forklift truck that performs handling and driving operations within a specific work area; and a warning unit that warns an operator of the forklift truck, characterized in that The forklift truck has a chassis on which steerable wheels are attached; a fork formed at the front of the chassis; a sensor unit that measures the weight load on the fork, the vehicle speed of the chassis, and the rotation angle of the steerable wheels; a first control unit that controls the handling and transport operations; and a second control unit that controls the warning unit, features the second control unit a first determination process in which it is determined that a claw retraction operation by the fork occurs if a reverse travel distance of the chassis from a time at which the weight load has changed to a state of less than a first threshold value is within a certain first distance, and a first detection processing in which it is recognized that a first hazardous action has occurred if the rotation angle during the claw retraction operation is at least a certain first angle, and The warning unit issues a warning when the second control unit has detected that the first hazardous action has occurred.

[0009] The warning system described above can be designed such that the second control unit a second determination process in which it is determined that a load-handling operation by the fork takes place if the reverse travel distance of the chassis from a time at which the weight load has changed to a state of at least one certain second threshold value is within a certain second distance, and a second detection processing in which it is recognized that a second hazardous action has occurred if the rotation angle during the load handling operation is at least a certain second angle, performs, and the warning unit issues the warning when the second control unit has detected that the second hazardous action has occurred.

[0010] The warning system described above can be designed such that the first control unit, as an action to restrict handling and driving operations, limits the vehicle speed or forces the chassis to stop when the second control unit has detected that the first hazardous action or the second hazardous action has occurred.

[0011] The warning system described above can be designed such that the second control unit is an input unit into which the measurement signals from the sensor unit are entered. a storage unit that stores first hazard action data, for which a condition for determining the first hazard action and a first hazard action identifier and the restriction action are linked, and second hazard action data, for which a condition for determining the second hazard action and a second hazard action identifier and the restriction action are linked, an action processing unit that performs the first determination processing, the first recognition processing, the second determination processing, and the second recognition processing, and an output unit which outputs a first signal relating to the first hazard action identification and the second hazard action identification to the warning unit and outputs a second signal relating to the restriction action to the first control unit, and the warning unit issues a warning when the first signal is entered, and the first control unit performs the restriction action when the second signal is entered.

[0012] The warning system described above can be designed such that the warning unit is a voice warning unit that issues the warning by means of a voice message, and The voice warning unit is a voice data storage unit that stores first voice data, for which the first hazard action identifier and first warning voice data are linked, and second voice data, for which the second hazard action identifier and second warning voice data are linked. a speech data processing unit that plays the first warning speech data when a first signal relating to the first hazard action identifier is entered, and plays the second warning speech data when a first signal relating to the second hazard action identifier is entered, and features a loudspeaker that outputs the voice message played by the speech data processing unit.

[0013] The warning system described above can be designed to further include an inattention detection unit that detects operator inattention. the inattention detection unit a camera unit that records the operator and generates a recording image, and an image processing unit that detects inattention from the recording image and outputs a detection signal to the second control unit, the second control unit performing a third detection processing in which it is recognized that a third hazardous action has occurred if an input of the detection signal occurs during the claw retraction operation or the load picking operation, and The warning unit issues the warning when the second control unit has detected that the third hazardous action has occurred.

[0014] The warning system described above can be designed such that the first control unit imposes a restriction on the vehicle speed or a forced stop of the chassis when the second control unit has detected that the third hazardous action has occurred.

[0015] To solve the above problem, a warning system according to the present invention is required, which warns a forklift truck that is performing handling and driving operations in a specific work area; and a warning unit that warns an operator of the forklift truck, characterized in that the forklift truck has a chassis on which steerable wheels are fitted; a fork that is formed at the front of the chassis; a sensor unit that measures the weight load on the fork, the vehicle speed of the chassis, and the rotation angle of the steerable wheels; a first control unit that controls the handling and transport operations; and a second control unit that controls the warning unit, the second control unit a second determination process in which it is determined that a load-handling operation by the fork takes place if a reverse travel distance of the chassis from a time at which the weight load has changed to a state of at least a certain second threshold value is within a certain second distance, and a second detection processing step, which recognizes that a second hazardous action has occurred if the rotation angle during load handling is at least a certain second angle, and The warning unit issues the warning when the second control unit has detected that the second hazardous action has occurred.

[0016] To solve the above problem, a forklift truck according to the present invention is required, which performs handling and driving operations in a specific work area, characterized in that the forklift a chassis on which steerable wheels are fitted; a fork that is formed at the front of the chassis; a sensor unit that measures the weight load on the forks and the vehicle speed of the chassis; and a control unit that controls the handling and driving operations, and the control unit performs an initial determination process in which it is determined that a claw retraction operation by the fork occurs if a reverse travel distance of the chassis from a point in time at which the weight load has changed to a state of less than a first threshold value is within a certain first distance, and performs an initial restriction processing in which a restriction of the vehicle speed is imposed if it has been determined that a claw retraction operation is taking place.

[0017] To solve the above problem, a forklift truck according to the present invention, which performs handling and driving operations in a specific working area, is characterized in that the forklift truck a chassis on which steerable wheels are fitted; a fork that is formed at the front of the chassis; a sensor unit that measures the weight load on the forks and the vehicle speed of the chassis; and a control unit that controls the handling and driving operations, and the control unit performs a second determination processing in which it is determined that a load picking operation by the forks takes place if a reverse travel distance of the chassis from a time at which the weight load has changed to a state of at least a certain second threshold value is within a certain second distance, and a second restriction processing in which a restriction of the vehicle speed is carried out if it has been determined that a load picking operation takes place, undertakes. Result of the invention

[0018] The present invention provides a warning system that allows the operator to easily assess dangerous actions and a forklift truck that can suppress these dangerous actions. Simple explanation of the drawings Fig. Figure 1 is a view showing a forklift truck according to a first embodiment. Fig. Figure 2 is a block diagram of a first control unit of the forklift truck according to the first embodiment. Fig. Figure 3 is a block diagram of a second control unit and a voice warning unit of the forklift truck according to the first embodiment. Fig. 4 is a view explaining the load handling operation. Fig. Figure 5 is a view showing the relationship between the forklift, a server, and an administrative device in the first embodiment. Fig. Figure 6 is a view showing a forklift truck according to a second embodiment. Fig. Figure 7 is a block diagram of a second control unit, an inattention detection unit and a voice warning unit of the forklift according to the second embodiment. Fig. Figure 8 is a view showing a forklift truck according to a third embodiment. Fig.Figure 9 is a block diagram of a first control unit of the forklift truck according to the third embodiment. Embodiments of the invention

[0019] The following descriptions of embodiments of the warning system and the forklift truck according to the present invention are explained with reference to the accompanying drawings.

[0020] Fig. Figure 1 shows a warning system and a forklift truck 1A according to a first embodiment of the present invention. The warning system according to the first embodiment is formed by at least one forklift truck 1A and a voice warning unit 2 mounted on the forklift truck 1A.

[0021] The forklift 1A performs handling and travel operations within a specific work area. These handling and travel operations comprise a handling operation and a travel operation, and the travel operation includes a turning operation. The work area is, for example, an area within any building, such as a factory, a warehouse, or the like. At least one rack R is set up within the work area, and freight items W (including pallets) are stored in the rack R.

[0022] The forklift 1A is a battery-powered counterbalance forklift comprising a chassis 10, a handling device 20, a sensor unit 30, a first control unit 40, a second control unit 50, the voice warning unit 2 and a battery (not shown).

[0023] On the lower part of the chassis 10, pairs of a left and a right front wheel 11 and a left and a right rear wheel 12 are formed. In the forklift 1A, the front wheels 11 are drive wheels, which are driven by a drive motor, and the rear wheels 12 are steered wheels, which are steered (rotated) by a steering motor.

[0024] In the upper part of the chassis 10, a driver's seat 13 is provided for the operator. In the lower part in front of the driver's seat 13, an accelerator pedal 14 and a brake 15 are provided, and on a dashboard in front of the driver's seat 13, a steering wheel 16 and a transfer control unit 17 are provided.

[0025] The accelerator pedal 14 is designed so that the operator can operate it from the driver's seat 13 by pressing it with their foot. When the accelerator pedal 14 is in the ON state (when the pedal is pressed), the chassis 10 is accelerated according to the extent of the pedal depressurization (the accelerator pedal opening degree), and when it is switched to the OFF state (the pedal is not pressed), weak regenerative braking is generated and the chassis 10 decelerates.

[0026] The brake 15 is a brake pedal designed so that the operator in the driver's seat 13 can actuate it by pressing it with their foot. When the brake 15 is in the ON state (when the pedal is pressed), a weaker regenerative braking effect than the regenerative braking effect of the accelerator pedal 14 is generated, and the chassis 10 is slowed down, while in the OFF state no regenerative braking effect is generated.

[0027] The steering wheel 16 is connected to the rear wheels 12 via a steering control mechanism 42, which will be described later. The operator can change the orientation (angle of rotation) of the rear wheels 12 by turning the steering wheel 16 in the direction of rotation. When the steering wheel 16 is not turned (during forward travel), the angle of rotation of the rear wheels is 0°.

[0028] The handling unit 17 has a lifting lever and a rocker lever. The lifting lever and the rocker lever are connected to the handling device 20 via a handling control mechanism 43, which will be described later. The operator can operate the handling device 20 by actuating the lifting lever and the rocker lever.

[0029] A head guard 18 is formed in the upper area of ​​the chassis 10 and above the driver's seat 13. The head guard 18 is formed by a pair of left and right front pillars, a pair of left and right rear pillars, and a roof.

[0030] The handling device 20 is formed by a lifting frame 21, a lifting support 22, a fork 23, a rear support 24, a tilting cylinder 25 and a lifting cylinder 26.

[0031] The lifting mast 21 is formed at the front of the chassis 10 and raises and lowers the forks 23. The lifting mast 21 has an outer mast and an inner mast. The outer mast has a pair of left and right guide rails extending vertically and a crossbeam connecting the upper end regions of the guide rails. The inner mast is formed on the inside of the guide rails of the outer mast and raises and lowers along the guide rails of the outer mast.

[0032] The lifting carrier 22 holds the fork 23 and raises and lowers along the lifting frame 21. The lifting carrier 22 is attached to one end of a lifting chain and, in a state where it is suspended from the lifting chain, raises and lowers along the inner mast. The other end of the lifting chain is attached to a lower part of the outer mast via a sprocket formed on the upper part of the lifting cylinder 26.

[0033] The fork 23 is a pair consisting of a left and a right L-shaped arm and is formed on the front surface of the lifting carrier 22. A cargo piece W is loaded onto the fork 23.

[0034] The rear support 24 is a frame body formed on the upper part of the lifting beam 22, which prevents a cargo piece W loaded onto the forks 23 from falling backwards. When the lifting frame 21 (the inner mast) raises or lowers, the lifting beam 22, the forks 23 and the rear support 24 also raise or lower.

[0035] The tilting cylinder 25 is a hydraulic cylinder used to tilt the lifting frame in the forward-backward direction. In the present embodiment, the tilting cylinder 25 extends and tilts the lifting frame 21 forward when the rocker arm is tilted forward, and the tilting cylinder 25 retracts and tilts the lifting frame 21 backward when the rocker arm is tilted backward. When the rocker arm returns to its neutral position (a position in which it is neither tilted forward nor backward), the tilting movement of the lifting frame 21 stops.

[0036] The lifting cylinder 26 is a hydraulic cylinder used to raise or lower the lifting frame 21. In the present embodiment, the lifting cylinder 26 retracts and the inner mast is lowered when the lifting lever is tilted forward, and the lifting cylinder 26 extends and the inner mast is raised when the lifting lever is tilted backward. When the lifting lever returns to its neutral position (a position where it is neither tilted forward nor backward), the raising or lowering of the inner mast stops.

[0037] The sensor unit 30 comprises a load sensor 31, a vehicle speed sensor 32, and a rotation angle sensor 33. The load sensor 31 measures the weight load of a cargo piece W loaded onto the fork 23. For example, a pressure sensor that measures the presence or absence of a weight load based on the pressure of the lifting cylinder 26 can be used as the load sensor 31. The vehicle speed sensor 32 measures the vehicle speed of the chassis 10. For example, a speed sensor that measures the travel speed of the chassis 10 based on the rotational speed and direction of rotation of the drive motor can be used as the vehicle speed sensor 32. The rotation angle sensor 33 measures the rotation angle of the rear wheels 12.For example, a rotation angle sensor 33 can be an angle sensor that measures the rotation angle of the rear wheels 12 based on the rotation angle of the steering wheel 16, or an angle sensor that measures the rotation angle of the rear wheels 12 based on the rotation angle of a pivot axis of the rear wheels 12.

[0038] Furthermore, the sensor unit 30 includes an accelerator pedal sensor 34 and a brake sensor 35, which are located in Fig. Figure 2 shows the accelerator pedal sensor 34 detects the degree of opening of the accelerator pedal 14. The brake sensor 35 detects the state (the on / off state) of the brake 15.

[0039] The first control unit 40 is located inside the chassis 10 and controls the handling and travel operations, as well as communication with the second control unit 50. The first control unit 40 comprises, as described in Fig. Figure 2 shows a driving control mechanism 41, the steering control mechanism 42 and the handling control mechanism 43.

[0040] The driving control mechanism 41 receives measurement signals from the accelerator pedal sensor 34, the brake sensor 35, and the vehicle speed sensor 32 and controls the front wheels 11, which are the drive wheels. The driving control mechanism 41 includes, for example, a driving controller, a driving inverter, a driving motor, a hydraulic circuit, and the like.

[0041] The driving control mechanism 41, as the control system for lifting and driving operations, employs speed control to approximate the driving speed of the chassis 10 to a target speed. Specifically, the driving control mechanism 41 determines the driving speed of the chassis 10 based on the measurement signal from the vehicle speed sensor 32 and calculates the target speed based on the detection signal from the accelerator pedal sensor 34 and / or the detection signal from the brake sensor 35. The driving control then performs PI or PID control to approximate the driving speed to the target speed. The target speed is calculated, for example, using the formula "Target speed = Set speed × Accelerator pedal opening [%]". The set speed is a speed that has been predefined in the driving control mechanism.

[0042] The steering control mechanism 42 receives detection information regarding the direction and angle of rotation of the steering wheel 16 and controls the rear wheels 12, which are the steered wheels. The steering control mechanism 42 includes, for example, a steering motor, a power steering device, a hydraulic circuit, and the like. The steering control mechanism 42 has the same design as the steering control mechanism in a conventional battery-powered forklift.

[0043] The handling control mechanism 43 receives actuation signals (measurement signals) from the handling actuation unit 17 (the lifting lever and the rocker arm) and controls the handling device 20. The handling control mechanism 43 includes, for example, a handling controller, a handling inverter, a handling motor, a hydraulic circuit, and the like. The handling control mechanism 43 has the same structure as the handling control mechanism in a conventional battery-powered forklift.

[0044] The second control unit 50, for example, includes a data logger unit (DLU) and is mounted on a front column of the head guard 18. As in Fig. As shown in Figure 3, the second control unit 50 has an input unit 51, a storage unit 52, a processing unit 53 and an output unit 54.

[0045] The input unit 51 receives the measurement signals from the sensor unit 30. Specifically, the input unit 51 receives from the load sensor 31 the measurement signal regarding the presence or absence of a weight load on the fork 23, from the vehicle speed sensor 23 the measurement signal regarding the vehicle speed of the chassis 10, and from the rotation angle sensor 33 the measurement signal regarding the rotation angle of the rear wheels 12.

[0046] The storage unit 52 stores several hazardous action data, for which a specific hazardous action identifier (hereinafter referred to as ID), a predefined hazardous action, a condition for determining the hazardous action, and a restriction action for driving and handling operations are linked together. In the present embodiment, the ID is a number, but the ID can also be a letter or a symbol, or a combination of a letter, a symbol, and a number.

[0047] The operator or administrator of the system can modify the contents of the hazard response data stored in storage unit 52 and add new hazard response data. For example, the two hazard response data shown in Table 1 below may be among the multiple hazard response data. Table 1 ID Dangerous act Determination condition Restrictive action 001 Rotation during claw retraction operation Presence of rotation during claw retraction Vehicle speed limit 002 Rotation during load handling Presence of rotation during load handling operation Vehicle speed limit

[0048] For the hazard action data with ID "001", the hazard action "Rotation during claw retraction operation", the determination condition "Presence of a rotation during claw retraction operation", and the restriction action "Restriction of vehicle speed" are linked to ID "001". The hazard action "Rotation during claw retraction operation" defines the hazard action (corresponding to the "first hazard action" of the present invention) that the forklift 1A performs a rotation operation during claw retraction operation. The determination condition above consists of the detection of a rotation operation during claw retraction operation as a condition for determining this hazard action.The restriction action "Vehicle speed restriction" defines that the first control unit 40, upon fulfillment of the above determining condition, imposes a restriction on the vehicle speed (for example, to an upper limit of 4 km / h). This means that the forklift 1A is prohibited from traveling at a speed exceeding this upper limit.

[0049] For the hazard action data with ID "002", the hazard action "Rotation during load picking operation", the determination condition "Presence of a rotation during load picking operation", and the restriction action "Limitation of vehicle speed" are linked to ID "002". The hazard action "Rotation during load picking operation" defines the hazard action (corresponding to the "second hazard action" of the present invention) that the forklift 1A performs a rotation operation during load picking operation. The determination condition above consists of the detection of a rotation operation during load picking operation as a condition for determining this hazard action.The restriction action “restriction of vehicle speed” defines that the first control unit 40, upon fulfillment of the above determination condition, imposes a restriction of the vehicle speed (for example, to an upper limit speed of 4 [km / h]).

[0050] The restriction action "Vehicle Speed ​​Limit" of ID "001" and / or ID "002" can be changed to a restriction action "Forced Stop". The restriction action "Forced Stop" defines that the first control unit 40, upon fulfillment of the above determining condition, slows down the chassis 10 and ultimately stops it. For example, the first control unit 40 can calculate the target speed of the chassis 10 using the formula "Target Speed ​​= Set Speed ​​× Accelerator Pedal Opening Degree [%]". The accelerator pedal opening degree is 0% when the accelerator pedal 14 is in the off state, increases proportionally to the extent of accelerator pedal depressurization when the accelerator pedal 14 enters the on state, and reaches a maximum of 100%.When the above restriction action is performed, the first control unit 40 changes the setting speed stepwise to a smaller absolute value and ultimately to zero.

[0051] Furthermore, the storage unit can store 52 hazardous action data entries, for which an ID, a hazardous action, and a determining condition are linked (no link exists to a restriction action during driving and handling operations). The hazardous actions in question correspond, for example, to not wearing a seatbelt, a decrease in the battery's remaining charge, forgetting to engage the parking brake, or similar situations.

[0052] The processing unit 53 determines, by performing a first determination processing, a first recognition processing, a second determination processing and a second recognition processing, whether the determination condition of a respective hazardous act is fulfilled or not, and specifies the hazardous act that fulfills the determination condition (the hazardous act data).

[0053] The first determination processing is a process to determine whether a claw retraction operation is taking place. The processing unit 53, which initiated the first determination processing, determines, based on the measurement signal from the load sensor 31 received by the input unit 51, whether the weight load has changed from a state of a certain first threshold or higher to a state of less than the first threshold. The first threshold is set to a value that allows a distinction between a state in which a weight load is present and a state in which no weight load is present.Since the state of the fork 23 changes, for example, when a piece of cargo W is placed on the shelf R, from the state of having a weight load to the state of not having a weight load, the measurement signal (the measured value) of the load sensor 31 changes from the state of at least the first threshold value to the state of less than the first threshold value.

[0054] When the weight load changes to a state below the first threshold, the processing unit 53 calculates the reverse travel distance of the chassis 10 from the point in time when the weight load changed to a state below the first threshold, based on the measurement signal from the vehicle speed sensor 32 obtained by the input unit 51. Simultaneously, the processing unit determines whether the weight load is below the first threshold and whether the aforementioned reverse travel distance lies within a predefined first distance. Here, the first distance is set, for example, to a value greater than the dimension of the fork 23 in the forward-reverse direction.In other words, the first distance is set to a value that allows assessment of whether the fork 23 has been fully retracted from the pallet of the cargo item W or not. However, the first distance can also be set to a value of at most the dimension of the fork 23 in the forward-backward direction.

[0055] As described above, during the first determination processing, the processing unit 53 determines that the state of the forklift 1A is claw retraction operation if the weight load is less than the first threshold and the reversing distance is within the first distance.

[0056] The first detection processing is a process to recognize the hazardous action "presence of rotation during claw retraction." The first detection processing can be performed if the first determination processing determines that claw retraction is occurring. The first detection processing can also be included in a part of the first determination processing.

[0057] The processing unit 53, which has initiated the initial detection processing, determines, based on the measurement signal from the input unit 51 of the rotation angle sensor 33, whether or not the rear wheels 12 rotated during the claw retraction operation. For example, the processing unit 53 determines that rotation occurred if the rotation angle of the rear wheels 12 is a certain initial angle or greater. This initial angle can be set to any value greater than 0°.

[0058] As described above, during the first recognition processing, the processing unit 53 recognizes that the hazardous action “rotation during claw retraction operation” is present, i.e., the hazardous action data with ID “001” is present if the rotation angle is at least the first angle in a state where the weight load is less than the first threshold and the reversing distance is within the first distance.

[0059] The second determination processing step is used to determine whether a load-bearing operation is taking place. The processing unit 53, which initiated the second determination processing step, uses the measurement signal from the load sensor 31, received by the input unit 51, to determine whether the weight load has changed from a state of less than a second threshold value to a state of at least the second threshold value. The second threshold value is set to such a value that a distinction can be made between a state in which a weight load is present and a state in which no weight load is present.Since the state of the fork 23 changes, for example, when a freight item W lying on the shelf R is lifted with the fork 23, from the state of no weight load to the state of presence of a weight load, the measurement signal (the measured value) of the load sensor 31 changes from the state of less than the second threshold value to the state of at least the second threshold value. The second threshold value can also be set to the same value as the first threshold value.

[0060] If the weight load has changed to a state of at least the second threshold value, the processing unit 53 calculates the reverse travel distance of the chassis 10 from the time the weight load changed to a state of at least the second threshold value, based on the measurement signal from the vehicle speed sensor 32 obtained by the input unit 51. Simultaneously, the processing unit 53 determines whether the weight load is in a state of at least the second threshold value and whether the aforementioned reverse travel distance lies within a predefined second distance. Here, the second distance is determined as in Fig.The second distance is set to a value greater than dimension L in the forward-backward direction of the shelf's loading space (R). In other words, the second distance is set to a value that allows determination of whether the cargo item W has been completely removed from the shelf. The second distance can also be set to a value less than dimension L in the forward-backward direction of the shelf's loading space (R).

[0061] As described above, during the second determination process, processing unit 63 determines that the state of the forklift 1A is the load-handling operation if it is determined that the weight load is at least the second threshold and the reverse travel distance is within the second distance.

[0062] The second detection processing step is used to identify the hazardous action "presence of rotation during load-handling operation." This second detection processing step can be performed if the second determination processing step determines that load-handling operation is occurring. The second detection processing step can also be integrated into a portion of the first determination processing step.

[0063] The processing unit 53, which has initiated the second detection processing, determines, based on the measurement signal from the input unit 51 of the rotation angle sensor 33, whether or not the rear wheels 12 were rotated during load-bearing operation. For example, the processing unit 53 determines that rotation occurred if the rotation angle of the rear wheels 12 is a certain second angle or greater. This second angle can be set to any value greater than 0°.

[0064] As described above, during the second recognition processing, the processing unit 53 recognizes that the hazardous action "rotation during load handling operation" is present, i.e., the hazardous action data with ID "002" is present if the rotation angle is at least the second angle in a state where the weight load is at least the second threshold and the reverse travel distance is within the second distance.

[0065] The output unit 54 sends a first signal, relating to the ID of the hazard action data recognized by the processing unit 53, to the voice warning unit 2, and a second signal, relating to the restriction action associated with this ID, to the first control unit 40. The transmission times of the first signal and the second signal can be the same or different.

[0066] The voice warning unit 2 is mounted under the roof of the head guard 18 and comprises a voice data storage unit 2A, a voice data processing unit 2B, and a loudspeaker 2C. The voice warning unit 2 emits a voice warning (an alarm) to the operator of the forklift 1A.

[0067] The voice message of the present invention is a spoken message that can transmit information to the operator. The voice message of the present invention does not contain an independent sound effect such as a buzzing tone, but may contain a sound effect if it precedes or follows the spoken message.

[0068] The voice data storage unit 2A stores multiple voice data sets, for which data from voice messages for warning purposes (hereinafter referred to as warning voice data) are linked to IDs. Among the multiple voice data sets are, for example, the two voice data sets shown in Table 2 below. Table 2 ID Warning voice data 001 Fork retraction operation! Do not rotate the vehicle! 002 Load handling operation! Do not rotate the vehicle!

[0069] The voice data with ID "001" is linked to the warning voice data "Fork retraction operation! Do not turn the vehicle!" The warning voice data for ID "001" contains the words (information) "turn" and "claw retraction," which the operator associates with the circumstances "turning operation" and "fork retraction operation" as a hazardous action.

[0070] The voice data with ID "002" is linked to the warning voice data "Load picking operation! Do not turn the vehicle!" The warning voice data for ID "002" contains the words (information) "turn" and "load picking," which the operator associates with the circumstances "turning operation" and "load picking operation" as a hazardous action.

[0071] The operator and administrator of the system in question can modify the warning voice data stored in voice data storage unit 2A and can add new voice data. A memory card, such as an SD card or USB flash drive, can be used for voice data storage unit 2A, allowing warning voice data to be overwritten. The operator or administrator can, for example, create warning voice data in a file format such as WAV and store it in voice data storage unit 2A.

[0072] The speech data processing unit 2B receives the first signal issued by the output unit 54 and plays back the warning speech data associated with the ID of the first signal in the speech data storage unit. For example, if the speech data processing unit 2B receives a first signal from the output unit 54 associated with the ID "001", it plays back the warning speech data with the identifier "0001", "Fork retraction operation! Do not turn the vehicle!" The speech data processing unit 2B contains, for example, a speech playback module.

[0073] Speaker 2C is connected to the speech data processing unit 2B and outputs the voice message of the warning voice data played back by the speech data processing unit 2B. For example, if the speech data processing unit 2B plays the warning voice data "Fork retraction operation! Do not turn the vehicle!" with ID "001", the speaker outputs the voice message "Fork retraction operation! Do not turn the vehicle!"

[0074] As described above, the voice warning unit 2 in the warning system and the forklift 1A, according to the present embodiment, warns (alarms) the operator by means of a voice message. Therefore, the operator can easily assess which hazardous activity has been detected. For example, the operator, hearing the information contained in the voice message of the voice warning unit 2, can immediately assess whether the hazardous activity with ID "001" or ID "002" has been detected and take appropriate action.

[0075] Since, according to the present embodiment, the warning system and the forklift 1A link actions to restrict handling and travel operations with defined hazardous actions, the first control unit 40 can restrict handling and travel operations based on the aforementioned restrictive actions if the operator's reaction is delayed. Therefore, according to the present embodiment, the warning system and the forklift 1A can suppress defined hazardous actions. The operations management system

[0076] As in Fig. As shown in Figure 5, the warning system according to the first embodiment can also include a server 3 and an administration device 4 and form an operational management system for the forklift 1A.

[0077] Server 3 is connected to forklift 1A via communication. Server 3 can be, for example, a physical server or a virtual server such as a cloud. While the voice warning unit 2 is playing back warning voice data, forklift 1A can upload (store on the server) video data recorded and generated by a tachograph integrated into sensor unit 30 to Server 3.

[0078] The management device 4 is connected to the server 3 via communication. The management device 4 can be, for example, a personal computer (PC) or a smartphone. The management device 4 can receive the video feed from the server 3. This allows the administrator of the warning system to check the video feed on the management device 4 at the time the warning voice data is being played. Second embodiment

[0079] Fig.Figure 6 shows a warning system and a forklift 1B according to a second embodiment of the present invention. The warning system according to the second embodiment is formed by at least one forklift 1B and a voice warning unit 2 mounted on the forklift 1B.

[0080] The forklift 1B has the same construction as the forklift 1A of the first embodiment, except for the fact that an inattention detection unit 60 is provided and the fact that controls are made in connection with the inattention detection unit 60.

[0081] The inattention detection unit 60 serves to detect the operator's inattention in the driver's seat 13 and is, for example, installed under the roof of the head guard 18. As in Fig. As shown in Figure 7, the inattention detection unit 60 includes a camera unit 61 and an image processing unit 62.

[0082] The camera unit 61 records the operator and generates a captured image. The image processing unit 62 performs any generally known image processing on the captured image generated by the camera unit 61 and detects inattention on the part of the operator. The image processing unit 62 can detect the orientation of the operator's face or whether the operator is looking away from the line of sight.

[0083] The image processing unit 62 can also detect that the operator is inattentive if the operator's face is not oriented towards the front of the chassis 10, or if the operator's line of sight is not directed towards the front of the chassis 10. If the detection range for inattentiveness is to be extended, the vertical direction can also be taken into account, and the image processing unit 62 can detect that the operator is inattentive if the operator's face is not oriented towards the cargo W, or if the operator's line of sight is not directed towards the cargo W.

[0084] The input unit 51 receives a detection signal from the image processing unit 62, which has detected an inattention of the operator, regarding the detection of this inattention.

[0085] In storage unit 52, in addition to the hazard action data with ID “001” and the hazard action data with ID “002”, hazard action data with ID “003” and hazard action data with ID “004”, which are shown in Table 3 below, are stored in advance. Table 3 ID Dangerous act Determination condition Restrictive action 003 Inattention during claw retraction operation Presence of inattention during claw retraction operation Vehicle speed limit 004 Inattention during load handling operations Presence of inattention during load handling operation Vehicle speed limit

[0086] For the hazard action data with ID "003", the hazard action "Inattention during claw retraction operation", the determination condition "Presence of inattention during claw retraction operation", and the restriction action "Restriction of vehicle speed" are linked to ID "003". The hazard action "Inattention during claw retraction operation" defines the hazard action (corresponding to the "third hazard action" of the present invention) that the operator is inattentive during the claw retraction operation of the forklift 1B. The determination condition above consists of the detection of inattention during claw retraction operation as a condition for determining this hazard action.The restriction action “restriction of vehicle speed” defines that the first control unit 40, upon fulfillment of the above determination condition, imposes a restriction of the vehicle speed (for example, to an upper limit speed of 4 [km / h]).

[0087] For the hazard action data with ID "004", the hazard action "Inattention during load handling," the determination condition "Presence of inattention during load handling," and the restriction action "Restriction of vehicle speed" are linked to ID "004." The hazard action "Inattention during load handling" defines the hazard action (corresponding to the "third hazard action" of the present invention) that the operator is inattentive during the load handling operation of the forklift 1B. The determination condition above is that inattention during load handling has been detected as a condition for determining this hazard action.The restriction action “restriction of vehicle speed” defines that the first control unit 40, upon fulfillment of the above determination condition, imposes a restriction of the vehicle speed (for example, to an upper limit speed of 4 [km / h]).

[0088] The restriction action “restriction of vehicle speed” of ID “003” and / or ID “004” can be changed to a restriction action “forced stopping” as in the first embodiment.

[0089] The processing unit 53, acting as a control in conjunction with the inattention detection unit 60, determines by performing a third recognition processing step whether the determination condition for the hazardous act in connection with inattention is met or not, and specifies the hazardous act that meets the determination condition (the hazardous act data).

[0090] The third detection processing step is designed to identify the hazardous action "inattention during claw retraction." This third detection processing step can be performed if the first determination processing step determines that claw retraction is occurring, or if the second determination processing step determines that load-bearing activity is occurring. The third detection processing step can also be incorporated into a portion of both the first and second determination processing steps.

[0091] If the processing unit 53, which performed the third recognition processing, determined during the first determination processing that claw retraction operation was present, and the input unit 51 receives a detection signal from the image processing unit 62, it specifies the hazardous action "Inattention during claw retraction operation", i.e., the hazardous action data with ID "0003". If, on the other hand, the processing unit 53 determined during the second determination processing that load picking operation was present, and the input unit 541 receives a detection signal from the image processing unit 62, it specifies the hazardous action "Inattention during load picking", i.e., the hazardous action data with ID "004".

[0092] The output unit 54 sends a first signal, relating to the ID of the hazard action data recognized by the processing unit 53, to the voice warning unit 2, and a second signal, relating to the restriction action associated with this ID, to the first control unit 40. The transmission times of the first signal and the second signal can be the same or different.

[0093] The speech data storage unit 2A also contains the speech data of ID “003” and the speech data of ID “004”, which are shown in Table 4 below. Table 4 ID Warning voice data 003 Don't be inattentive! 004 Don't be inattentive!

[0094] The voice data with ID "003" is linked to the warning voice data "Don't be inattentive!" with ID "003". The warning voice data of ID "003" contains the word (the information) that the operator associates with the circumstance of "inattentiveness" in the hazardous action. The same applies to the voice data of ID "004".

[0095] As described above, the voice warning unit 2 in the warning system and the forklift 1B, according to the present embodiment, warns (alarms) the operator by means of a voice message. Therefore, the operator can easily assess which hazardous activity has been detected. For example, the operator who hears the information contained in the voice message of the voice warning unit 2 can immediately assess which hazardous activity under IDs "001" to "004" has been detected and take appropriate action.

[0096] Since, according to the present embodiment, the warning system and the forklift 1B link actions to restrict handling and driving operations with defined hazardous actions, the first control unit 40 can restrict handling and driving operations based on the aforementioned restrictive actions if the operator's reaction is delayed. Therefore, according to the present embodiment, the warning system and the forklift 1B can suppress defined hazardous actions. The frequency of activation of the warning voice data

[0097] The examples above assume that the warning voice data is activated once, but the activation frequency can be changed as desired.

[0098] For example, the IDs in the speech data storage unit 2A can be linked to a number of plays or a playback time. If linked to a number of plays, the warning speech data can only be played back for the specified number of plays, and if linked to a playback time, the warning speech data can be played back repeatedly for the specified playback time.

[0099] On the other hand, it can be inconvenient for the operator if warning voice data is played back multiple times. In this case, the IDs in storage unit 52 or voice data storage unit 2A can be linked to a hazard level. The voice data processing unit 2B plays the warning voice data back several times when the hazard level exceeds a certain threshold, with the number of replays preferably increasing as the hazard level rises. For example, the hazard level can be divided into hazard level 1, hazard level 2, and hazard level 3, and the IDs in voice data storage unit 2A can be linked to the hazard level and the number of replays such that hazard level 1 results in a single replay, hazard level 2 in two replays, and hazard level 3 in three replays.

[0100] If the IDs of the hazardous actions in storage unit 54 are linked to a time for the output of the second signal, the output time can be set to be "after a certain time has elapsed since the output of the first signal." This specific time can be set appropriately depending on the level of hazard.

[0101] If the hazard level is divided into hazard level 1, hazard level 2, and hazard level 3 as described above, the specific time can be set such that a first specific time is set for hazard level 1, a second specific time (shorter than the first) is set for hazard level 2, and a third specific time (shorter than the second) is set for hazard level 3. The third specific time can also be zero. For example, hazard level 3 can be set for hazardous actions with IDs "001" and "002," and hazard level 1 can be set for hazardous actions with IDs "003" and "004."If the processing unit 53 has detected a hazardous action with ID “003” or ID “004”, the voice warning unit 2 warns (alarms) the operator by means of a voice message, and if the hazardous action with ID “003” or ID “004” is also detected after the first determined time has elapsed, the restriction action is carried out on the basis of the second signal.

[0102] By changing the output time for the second signal as described above, depending on the hazard level of the hazardous action, the hazardous action can be suppressed and safety ensured, while minimizing the decrease in the work efficiency of the forklift 1B. Third embodiment

[0103] Fig.Figure 8 shows a forklift truck 1C according to a third embodiment of the present invention. The forklift truck 1C can be included in the warning system according to the first embodiment and / or the second embodiment.

[0104] The forklift 1C has the same structure as the forklift 1A of the first embodiment, with the exception that instead of the first control unit 40 a first control unit 40' (corresponding to the "control unit" of the present invention) is formed, the sensor unit 30 does not contain a rotation angle sensor 33, and the fact that no second control unit 50 and no voice warning unit 2 are formed.

[0105] As in Fig. As shown in Figure 9, the first control unit 40' has the same structure as the first embodiment, except that it has a driving control mechanism 41' instead of the driving control mechanism 41.

[0106] In addition to the control of the drive control mechanism 41 of the first embodiment, the drive control mechanism 41' performs a control based on the measurement signal (the measured value) of the load sensor 31. This control includes the first determination processing, the first limitation processing, the second determination processing, and the second limitation processing.

[0107] The first determination processing is the same processing as the first determination processing performed by the processing unit 53 in the first embodiment. That is, the driving control mechanism 41' determines that the state of the forklift 1C is the claw retraction mode when the weight load is less than the first threshold and the reverse travel distance is within the first distance.

[0108] The first control processing is related to limiting the vehicle speed of the forklift 1C. The driving control mechanism 41' limits the driving speed of the forklift 1C (for example, to an upper limit of 4 km / h) when it has been determined that the forklift 1C is in claw retraction mode. This prevents the forklift 1C from traveling at a speed exceeding the upper limit during claw retraction.

[0109] The second determination processing is the same processing as the second determination processing performed by the processing unit 53 in the first embodiment. That is, the driving control mechanism 41' determines that the state of the forklift 1C is load-picking mode when the weight load is at least the second threshold value and the reverse travel distance is within the second distance.

[0110] The second restriction processing operation is related to limiting the vehicle speed of forklift 1C. The driving control mechanism 41' imposes a speed limit on forklift 1C (for example, to an upper limit of 4 km / h) when it has been determined that forklift 1C is in load-handling mode. This prevents forklift 1C from traveling at a speed exceeding the upper limit during load-handling operation.

[0111] Since the forklift 1C of the present embodiment limits the vehicle speed of the chassis 10 before any rotation actually takes place, the operator's safety awareness can be increased, and a "rotation during claw retraction" or a "rotation during load picking," which constitutes a hazardous action, can be suppressed. The vehicle speed can also be limited in the forklift 1A before a rotation operation is performed, in the same way as in the forklift 1C. In this case, the first control unit 40 performs the limiting action (limiting the vehicle speed) before the second control unit 50 detects the hazardous action described above.

[0112] In the foregoing, embodiments of the warning system and the forklift truck according to the present invention have been explained, but the present invention is not limited to the embodiments described above.

[0113] Provided that the alarm system according to the present invention is an alarm system comprising a forklift truck that performs handling and driving operations in a specific work area; and a warning unit that warns an operator of the forklift truck, wherein the forklift truck has a chassis on which steerable wheels are formed; a fork formed at the front of the chassis; a sensor unit that measures the weight load on the fork, the vehicle speed of the chassis, and the angle of rotation of the steerable wheels; and a first control unit that controls the handling and driving operations;and a second control unit that controls the warning unit, wherein the second control unit performs a first determination processing in which it is determined that a claw retraction operation by the fork occurs if a reverse travel distance of the chassis from a time at which the weight load has changed to a state of less than a first threshold value is within a certain first distance, and a first detection processing in which it is detected that a first hazardous action has occurred if the rotation angle during the claw retraction operation is at least a certain first angle, and the warning unit issues a warning when the second control unit has detected that the first hazardous action has occurred, the setup can be modified as desired.;

[0114] Or, provided that the alarm system according to the present invention is an alarm system comprising a forklift truck that performs handling and driving operations in a specific work area; and a warning unit that warns an operator of the forklift truck, wherein the forklift truck has a chassis on which steerable wheels are formed; a fork formed at the front of the chassis; a sensor unit that measures the weight load on the fork, the vehicle speed of the chassis, and the angle of rotation of the steerable wheels; and a first control unit that controls the handling and driving operations.and a second control unit that controls the warning unit, wherein the second control unit performs a second determination processing in which it is determined that a load-picking operation by the forks takes place if a reverse travel distance of the chassis from a time at which the weight load has changed to a state of at least a certain second threshold value is within a certain second distance, and a second detection processing in which it is detected that a second hazardous action has occurred if the rotation angle during the load-picking operation is at least a certain second angle, and the warning unit issues the warning when the second control unit has detected that the second hazardous action has occurred, the setup can be modified as desired.;

[0115] The warning unit is preferably a voice warning unit that provides the warning by means of a voice message; however, the warning can also be provided by means other than a voice message. The warning unit can warn the operator by activating a warning light or emitting an audible signal that does not include a voice message (for example, a buzzing tone or an electronic tone). The operator can assess the hazardous action by changing the color or state of the light, the type of audible signal, or similar measures, depending on the hazardous action.

[0116] In the above embodiments, the forklift 1A, 1B is equipped with the voice warning unit, but the voice warning unit of the present invention can be located at a different location than the forklift 1A, 1B (for example, on a shelf R in the work area).

[0117] In the above embodiments, the forklift 1B is provided with the inattention detection unit 60, but the inattention detection unit of the present invention can be located at a different location than the forklift 1B (for example, on a shelf R in the work area).

[0118] Provided that the forklift truck according to the present invention is a forklift truck that performs handling and driving operations in a specific working area and has a chassis on which steerable wheels are formed; a fork formed on the front of the chassis; a sensor unit that measures the weight load on the fork and measures the vehicle speed of the chassis;and a control unit that controls the handling and travel operations, wherein the control unit performs a first determination processing in which it is determined that a claw retraction operation by the forks takes place if a reverse travel distance of the chassis from a time at which the weight load has changed to a state of less than a first threshold value is within a certain first distance, and a first limitation processing in which a limitation of the vehicle speed is carried out if it has been determined that a claw retraction operation takes place, the setup can be modified as desired.;

[0119] Or as long as the forklift truck according to the present invention is a forklift truck that performs handling and driving operations in a specific working area and has a chassis on which steerable wheels are formed; a fork formed on the front of the chassis; a sensor unit that measures the weight load on the fork and the vehicle speed of the chassis;and a control unit that controls the handling and driving operations, and the control unit has a second determination processing in which it is determined that a load picking operation by the forks takes place if a reverse travel distance of the chassis from a time at which the weight load has changed to a state of at least a certain second threshold value is within a certain second distance, and a second restriction processing in which a restriction of the vehicle speed is carried out if it has been determined that a load picking operation takes place, the structure can be modified as desired.;

[0120] The forklift truck according to the present invention has been described in the above embodiments using a counterweight forklift truck, but it can also be a reach truck or another type of forklift truck. Reference symbol list 1A, 1B, 1C Forklifts 2 voice warning units 10 chassis 11 Front wheel 12 rear wheel 13 Driver's seat 14 Accelerator pedal 15 Brake 16 Steering wheel 17 Handling unit 18 Head protection 20 Handling device 21 Lifting frame 22 lifting carriers 23 Fork 24 rear support 25 tilting cylinders 26 lifting cylinders 30 sensor units 31 Load sensor 32 Vehicle speed sensor 33 Rotation angle sensor 40, 40' first control unit 50 second control unit 60 Inattention Detection Unit

Claims

Warning system, wherein the warning system comprises a forklift truck that performs handling and driving operations in a specific work area; and a warning unit that warns an operator of the forklift truck, characterized in that the forklift truck has a chassis on which steerable wheels are formed; a fork formed at the front of the chassis; a sensor unit that measures the weight load on the fork, the vehicle speed of the chassis, and the angle of rotation of the steerable wheels; a first control unit that controls the handling and driving operations;and a second control unit that controls the warning unit, the second control unit performing a first determination processing in which it is determined that a claw retraction operation by the fork occurs if a reverse travel distance of the chassis from a time at which the weight load has changed to a state of less than a first threshold value is within a certain first distance, and a first detection processing in which it is detected that a first hazardous action has occurred if the rotation angle during the claw retraction operation is at least a certain first angle, and the warning unit issues a warning if it has been detected by the second control unit that the first hazardous action has occurred. Warning system according to claim 1, characterized in that the second control unit performs a second determination processing in which it is determined that a load-picking operation by the fork takes place if the reverse travel distance of the chassis from a time at which the weight load has changed to a state of at least a certain second threshold value is within a certain second distance, and a second detection processing in which it is recognized that a second hazardous action has occurred if the rotation angle during the load-picking operation is at least a certain second angle, and the warning unit issues the warning when it has been recognized by the second control unit that the second hazardous action has occurred. Warning system according to claim 2, characterized in that the first control unit, as an action to restrict the handling and driving operation, restricts the vehicle speed or forces the chassis to stop when the second control unit has detected that the first dangerous action or the second dangerous action has occurred. Warning system according to claim 3, characterized in that the second control unit comprises an input unit into which the measurement signals of the sensor unit are input, a storage unit that stores first hazard action data, for which a condition for determining the first hazard action and a first hazard action identifier and the restriction action are linked, and second hazard action data, for which a condition for determining the second hazard action and a second hazard action identifier and the restriction action are linked, an action processing unit that performs the first determination processing, the first detection processing, the second determination processing and the second detection processing, and an output unit that outputs a first signal relating to the first hazard action identifier and the second hazard action identifier to the warning unit and a second signal relating to the restriction action.outputs to the first control unit, and the warning unit issues a warning when the first signal is entered, and the first control unit performs the restriction action when the second signal is entered. Warning system according to claim 4, characterized in that the warning unit is a voice warning unit that issues the warning by means of a voice message, and the voice warning unit comprises a voice data storage unit that stores first voice data, for which the first hazard action identifier and first warning voice data are linked, and second voice data, for which the second hazard action identifier and second warning voice data are linked, a voice data processing unit that plays the first warning voice data when a first signal relating to the first hazard action identifier is input, and plays the second warning voice data when a first signal relating to the second hazard action identifier is input, and a loudspeaker that outputs the voice message played by the voice data processing unit. Warning system according to claim 2, characterized in that it further comprises an inattention detection unit that detects inattention of the operator, the inattention detection unit a camera unit that records the operator and generates a recording image, and an image processing unit that detects inattention from the recording image and outputs a detection signal to the second control unit, the second control unit performs a third detection processing in which it is recognized that a third hazardous action has occurred if an input of the detection signal occurs during the claw retraction operation or the load picking operation, and the warning unit issues the warning when it has been recognized by the second control unit that the third hazardous action has occurred. Warning system according to claim 6, characterized in that the first control unit imposes a restriction of the vehicle speed or a forced stop of the chassis when the second control unit has detected that the third hazardous action has occurred. Warning system, wherein the warning system comprises a forklift truck that performs handling and driving operations in a specific work area; and a warning unit that warns an operator of the forklift truck, characterized in that the forklift truck has a chassis on which steerable wheels are formed; a fork formed at the front of the chassis; a sensor unit that measures the weight load on the fork, the vehicle speed of the chassis, and the angle of rotation of the steerable wheels; a first control unit that controls the handling and driving operations;and a second control unit that controls the warning unit, the second control unit performing a second determination processing in which it is determined that a load-picking operation by the forks occurs if a reverse travel distance of the chassis from a time at which the weight load has changed to a state of at least a certain second threshold is within a certain second distance, and a second detection processing in which it is detected that a second hazardous action has occurred if the rotation angle during the load-picking operation is at least a certain second angle, and the warning unit issues the warning when the second control unit has detected that the second hazardous action has occurred. A forklift truck that performs handling and driving operations within a specific work area, characterized in that the forklift truck has a chassis with steerable wheels; a fork formed at the front of the chassis; a sensor unit that measures the weight load on the fork and the vehicle speed of the chassis;and a control unit that controls the handling and travel operations, and the control unit performs a first determination processing in which it is determined that a claw retraction operation by the forks will occur if a reverse travel distance of the chassis from a time at which the weight load has changed to a state of less than a first threshold value is within a certain first distance, and a first restriction processing in which a restriction of the vehicle speed is applied if it has been determined that a claw retraction operation will occur.; A forklift truck that performs handling and driving operations within a specific work area, characterized in that the forklift truck has a chassis with steerable wheels; a fork formed at the front of the chassis; a sensor unit that measures the weight load on the fork and the vehicle speed of the chassis;and a control unit that controls the handling and driving operations, and the control unit includes a second determination processing in which it is determined that a load picking operation by the forks takes place if a reverse travel distance of the chassis from a time at which the weight load has changed to a state of at least a certain second threshold value is within a certain second distance, and a second restriction processing in which a restriction of the vehicle speed is carried out if it has been determined that a load picking operation takes place.;

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