A work machine, a control system for a work machine, and a method for controlling a work machine.

Abstract

In a work machine to which a work tool that performs object holding and releasing operations can be attached, the system automatically determines and sets whether or not the release permission switch is enabled. [Solution] The forklift 1 includes a work machine 3 to which a clamping device 10 that performs holding and releasing operations for objects can be attached, an operating lever 21 that is operated to operate the clamping device, a drive system 40 configured to drive the clamping device, and a controller 30 configured to control the drive system so that the clamping device is operated in response to the operation of the operating lever. The controller receives first and second input signals s1 and s2, including a signal from a release permission switch 23 for permitting or prohibiting the release operation of the clamping device, and determines whether the release permission switch is enabled in the forklift based on the first and second input signals, and makes settings according to the determination result.

Description

TECHNICAL FIELD

[0001] The present invention relates to the technical field of work machines to which a work implement that performs a holding operation for holding an object and a releasing operation for releasing the held object can be attached. BACKGROUND ART

[0002] Conventionally, work machines such as forklifts are configured such that an applicable work implement (attachment) can be replaced depending on the application. For example, Patent Document 1 describes a technology related to a clamp device as a work implement applicable to a forklift. This clamp device is configured to switch between a holding operation for holding (clamping / gripping) an object and a releasing operation for releasing the held object. The basic work implement for a forklift is a fork (e.g., a side shift fork, a hinged fork, a rotating fork, etc.). PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0003] Patent Document 1 Japanese Patent Laid-Open No. 2005-263410 SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0004] In a work machine having a work implement (clamp device) capable of performing a holding operation and a releasing operation for an object as described above, if the work implement accidentally performs a releasing operation while holding the object, the object will be dropped. For this reason, a release permission switch for permitting or prohibiting the releasing operation of the work implement is sometimes provided in the work machine. Accordingly, only when the release permission switch is on is the releasing operation of the work implement permitted, and when the release permission switch is off, the releasing operation of the work implement is prohibited, thereby preventing the work implement from accidentally performing the releasing operation.

[0005] The release permission switch described above is not provided on all work machines; some work machines do not have one. Therefore, it is necessary to configure settings within the work machine regarding the presence or absence of the release permission switch. However, if this setting is left to the user, it may not be set correctly, so it is desirable to enable automatic setting within the work machine.

[0006] Therefore, the present invention aims to enable automatic determination and setting of whether or not a release permission switch is enabled in a work machine to which a work tool that performs object holding and release operations can be attached. [Means for solving the problem]

[0007] In one aspect of the present invention, the work machine comprises a main body, a work tool that is operable relative to the main body and performs a holding operation for holding an object and a releasing operation for releasing the held object, an operating device that receives an operation for operating the work tool, a drive system that operates the work tool, and a controller configured to control the drive system to operate the work tool in response to an operation of the operating device, wherein the controller receives an input signal including a signal from a release permission switch for permitting or prohibiting the release operation of the work tool, and is configured to make settings related to the release permission switch when the release permission switch is enabled in the work machine. [Effects of the Invention]

[0008] According to the above embodiment, in a work machine to which a work tool that performs object holding and release operations can be attached, it is possible to automatically determine and set whether or not the release permission switch is enabled. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side view of a forklift according to an embodiment of the present invention. [Figure 2] This is a perspective view from above of a clamping device according to an embodiment of the present invention. [Figure 3] This is a block diagram showing the electrical configuration of a forklift according to an embodiment of the present invention. [Figure 4] This is a schematic diagram of the release permission switch according to an embodiment of the present invention. [Figure 5] This is an explanatory diagram of a method for determining whether a release permission switch is enabled or disabled according to an embodiment of the present invention. [Figure 6] This flowchart shows a control method according to an embodiment of the present invention. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. In all drawings used to illustrate the embodiments, the same reference numerals are generally used for the same components, and repeated descriptions of them will be omitted.

[0011] [Overall configuration of a forklift] First, the configuration of the forklift according to this embodiment will be described with reference to Figures 1 and 2. In this embodiment, a forklift is used as an example of the work machine. Figure 1 is a side view of the forklift according to this embodiment, and Figure 2 is a perspective view of the clamping device according to this embodiment.

[0012] As shown in Figure 1, the forklift 1 mainly consists of a main body 2, which includes a driver's seat 2C where an operator is seated and a vehicle 2R, and a work implement 3 located at the front of the main body 2. The work implement 3 has a clamping device 10 as a work tool (attachment) that can switch between a holding operation for holding (clamping / gripping) an object and a release operation for releasing the held object. The work implement 3 also has a mast 5 that extends vertically and a mast lift cylinder 6 that can be driven to raise and lower the clamping device 10 along the mast 5.

[0013] As shown in Figure 1, the forklift 1's main body 2 is equipped with a battery 7 as a power source, a drive motor 8 for driving the vehicle 2R using the power of the battery 7, a work motor 9 for operating the clamping device 10 using the power of the battery 7, an accelerator pedal 19 for receiving input to drive the vehicle 2R, a lift lever 20 for receiving input to raise and lower the clamping device 10, an operation lever 21 for receiving input to hold or release the clamping device 10, and a controller 30 for performing various controls on the forklift 1. The controller 30 controls the drive motor 8 based on the operation of the accelerator pedal 19 to drive the drive wheels 4 of the vehicle 2R. The controller 30 also controls the work motor 9 based on the operation of the lift lever 20 and the operation lever 21 to raise and lower the clamping device 10, or to hold or release the clamping device 10. Furthermore, the forklift 1 is not limited to being driven by batteries 7 and motors 8 and 9, but may also be driven by power generated from various power sources such as internal combustion engines and fuel cells.

[0014] Next, as shown in Figure 2, the clamping device 10 includes a clamping base 11 extending in the left-right direction, a pair of left and right clampers 12L and 12R disposed on the clamping base 11, and clamping cylinders 13L and 13R configured to drive the clampers 12L and 12R, respectively. More specifically, the clamping base 11 has a guide rail 11G extending in the left-right direction, and the clampers 12L and 12R each have a guide arm 12G slidably supported by the guide rail 11G and a clamping arm 12A disposed at one end of the guide arm 12G and extending in the front-rear direction. In the clampers 12L and 12R, the guide arm 12G is moved horizontally in the left-right direction by the clamping cylinders 13L and 13R, respectively, so that the opposing clamping arms 12A and 12A open and close in the left-right direction. As a result, the clamping device 10 is able to hold and release objects.

[0015] Furthermore, the mast lift cylinder 6 and the clamp cylinders 13L, 13R are driven using hydraulic pressure as a power source. On the other hand, the traveling body 2R of the main body 2 is configured to be driven and controlled independently of the mast lift cylinder 6 and the clamp cylinders 13L, 13R.

[0016] [Electrical Configuration of Forklift] Next, the electrical configuration of the forklift 1 according to the present embodiment will be described with reference to FIG. 3. As shown in FIG. 3, the forklift 1 includes an accelerator pedal 19 for driving the traveling body 2R, a lift lever 20 for raising and lowering the clamp device 10, an operation lever 21 operated by an operator to operate the clamp device 10 (such as holding operation and releasing operation), a release permission switch 23 for permitting or prohibiting the releasing operation of the clamp device 10, a seating pressure sensor 25 configured to detect whether the operator is seated on the driver's seat 2C, a seat belt sensor 26 configured to detect whether the operator wears a seat belt, a display device 27 that displays various screens and includes a touch panel 28 operable by the operator, a controller 30 configured to perform various controls in the forklift 1, and a drive system 40 configured to drive the traveling body 2R and working tools (attachments) such as the clamp device 10 based on control from the controller 30.

[0017] The release permission switch 23 is configured to be switchable between on and off by an operator's operation. The release permission switch 23 is operated by the operator to switch from off to on when causing the clamp device 10 to perform a releasing operation, thereby permitting the releasing operation of the clamp device 10. In contrast, when the release permission switch 23 is set to off (such as when operated by the operator to switch from on to off), the releasing operation of the clamp device 10 is prohibited. In one example, the release permission switch 23 is configured by a button or the like that is turned on when pressed and turned off when released, and is provided at a tip end of the operation lever 21 or the like.

[0018] Note that forklift 1 includes, in addition to a lift lever 20 and an operation lever 21, a tilt lever for tilting a mast 5 in the front-rear direction. Further, the forklift 1 may also have two or more operation levers 21. The operation lever 21 corresponds to an example of the "operating device" in the present invention.

[0019] Here, with reference to FIG. 4, a specific configuration of the release permission switch 23 according to the present embodiment will be described. FIG. 4 is a schematic diagram showing an electrical configuration of the release permission switch 23 according to the present embodiment.

[0020] As shown in FIG. 4, the release permission switch 23 is configured as a so-called c-contact type switch including an a-contact and a b-contact, and includes a common terminal 23c, a normally closed terminal 23nc, a normally open terminal 23no, and a switch unit 23sw. Specifically, in the release permission switch 23, the connection between the common terminal 23c and the normally closed terminal 23nc via the switch unit 23sw forms a b-contact (see reference sign x1), and the connection between the common terminal 23c and the normally open terminal 23no via the switch unit 23sw forms an a-contact (see reference sign x2).

[0021] In the release permission switch 23, a circuit in which connection / disconnection between the common terminal 23c and the normally closed terminal 23nc is switched by the switch unit 23sw constitutes a first switch sw1, and this first switch sw1 corresponds to the "normally closed type switch" in the present invention. Further, a circuit in which connection / disconnection between the common terminal 23c and the normally open terminal 23no is switched by the switch unit 23sw constitutes a second switch sw2, and this second switch sw2 corresponds to the "normally open type switch" in the present invention. As described above, the release permission switch 23 is configured by two switches (the first and second switches sw1, sw2). Furthermore, the release permission switch 23 is not limited to being composed of two switches; it may also be composed of three or more switches. In that case, the release permission switch 23 can be composed of a combination of normally closed switches and normally open switches as appropriate.

[0022] Furthermore, the release enable switch 23 ensures that a first input signal s1 is supplied to the controller 30 from the normally closed terminal 23nc of the first switch sw1, and a second input signal s2 is supplied to the controller 30 from the normally open terminal 23no of the second switch sw2. These first and second input signals s1 and s2 correspond to the current or voltage values ​​input to the controller 30, and indicate the state of the first and second switches sw1 and sw2, respectively, i.e., the closed state (connected state) or the open state (disconnected state / unconnected state). Basically, the current or voltage values ​​corresponding to the first and second input signals s1 and s2 are higher when the first and second switches sw1 and sw2 are in the closed state than when the first and second switches sw1 and sw2 are in the open state. In a typical example, when the first and second switches sw1 and sw2 are in the open state, the current or voltage values ​​are approximately 0.

[0023] Furthermore, as described above, the release permission switch 23 is turned off when the switch is not operated by an operator (for example, when the button is in the released state). When the release permission switch 23 is off, the common terminal 23c and the normally closed terminal 23nc are connected via the switch unit 23sw. In this case, the first input signal s1 indicates that the first switch sw1 is in the closed state, and the second input signal s2 indicates that the second switch sw2 is in the open state. On the other hand, the release permission switch 23 is turned on when the switch is operated by an operator (for example, when the button is pressed). When the release permission switch 23 is on, the common terminal 23c and the normally open terminal 23no are connected via the switch unit 23sw. In this case, the first input signal s1 indicates that the first switch sw1 is in the open state, and the second input signal s2 indicates that the second switch sw2 is in the closed state.

[0024] Returning to Figure 3, the controller 30 and drive system 40 of the forklift 1 will be described in detail. The controller 30 is a computer comprising one or more processors 31 (typically CPUs) and memory 35 such as ROM or RAM for storing various programs (including basic control programs such as the OS and application programs launched on the OS to realize specific functions) and various data that are interpreted and executed on the processor 31. Specifically, the processor 31 of the controller 30 has a solenoid control unit 32 for controlling the drive system 40 (particularly the open-side solenoid valve 41 and the closed-side solenoid valve 42 in the drive system 40) to hold or release the clamp device 10 in response to the operation of the operating lever 21, and a release control unit 33 for controlling the solenoid control unit 32 to allow or prohibit the release operation of the clamp device 10 in response to the on / off state of the release permission switch 23 (i.e., in response to the first and second input signals s1 and s2 input from the release permission switch 23).

[0025] The drive system 40 mainly comprises a drive motor 8 powered by the battery 7, a drive drive unit 46 that drives the vehicle 2R using the power of the drive motor 8, a motor 9 for the work equipment powered by the battery 7, and a hydraulic drive unit 44 that drives the clamping device 10 using the power of the motor 9. The controller 30 controls the drive motor 8 based on the operation of the accelerator pedal 19, thereby driving the drive wheels 4 of the vehicle 2R via the drive drive unit 46. This accelerates or decelerates the vehicle 2R. The controller 30 also controls the motor 9 based on the operation of the lift lever 20 and the operating lever 21, thereby raising and lowering the clamping device 10, or performing a holding or releasing operation of the clamping device 10 via the hydraulic drive unit 44. In this case, the controller 30 drives the mast lift cylinder 6 and clamp cylinders 13L and 13R of the clamping device 10 via the hydraulic drive unit 44 (Figures 1 and 2). Furthermore, in the drive system 40, the hydraulic drive unit 44 and the traction drive unit 46 are configured independently and are mainly composed of hydraulic pumps and the like. In this example, the hydraulic drive unit 44 and the travel drive unit 46 are configured independently, meaning that the travel body 2R and the work implement 3 use independent drive units. However, in other examples, a common drive unit may be used for both the travel body 2R and the work implement 3. In this case as well, the drive control can be performed independently for both the travel body 2R and the work implement 3. Furthermore, in yet another example, instead of configuring such a drive unit with a hydraulic system, the drive unit may be configured with any system such as an electric motor.

[0026] In this embodiment in particular, the drive system 40 includes an open-side solenoid valve 41 for releasing the clamping device 10 (i.e., opening the clamping arms 12A of the clampers 12L and 12R) and a closed-side solenoid valve 42 for holding the clamping device 10 (i.e., closing the clamping arms 12A). The hydraulic drive unit 44 drives the clamping device 10 using hydraulic pressure according to the state of these open-side solenoid valves 41 and closed-side solenoid valves 42. The opening degree of the open-side solenoid valves 41 and 42 is controlled according to the current supplied from the solenoid control unit 32 of the controller 30. The hydraulic drive unit 44 includes various pumps, valves, and oil passages, and supplies hydraulic fluid to the clamping cylinders 13L and 13R of the clamping device 10 and recovers hydraulic fluid from the clamping cylinders 13L and 13R.

[0027] In this embodiment, the release control unit 33 of the controller 30 determines whether the release permission switch 23 is on or off based on the first and second input signals s1 and s2 from the release permission switch 23, and in particular based on the states of the first and second switches sw1 and sw2 indicated by the first and second input signals s1 and s2. Specifically, the release control unit 33 determines that the release permission switch 23 is off if the first input signal s1 indicates that the first switch sw1 is in a closed state, and the second input signal s2 indicates that the second switch sw2 is in an open state. In this case, the release control unit 33 controls the solenoid control unit 32 to prevent the clamp device 10 from performing a release operation, regardless of the operation of the operating lever 21, in order to prohibit the release operation of the clamp device 10. As a result of this control, current is no longer supplied from the solenoid control unit 32 to the open-side solenoid valve 41 of the drive system 40, and the open-side solenoid valve 41 does not open, so the release operation of the clamp device 10 is prevented.

[0028] On the other hand, the release control unit 33 determines that the release permission switch 23 is ON if the first input signal s1 indicates that the first switch sw1 is open and the second input signal s2 indicates that the second switch sw2 is closed. In this case, the release control unit 33 permits the release operation of the clamp device 10 and controls the solenoid control unit 32 to cause the clamp device 10 to perform a release operation in response to the operation of the operating lever 21. As a result of this control, current is supplied from the solenoid control unit 32 to the open-side solenoid valve 41 of the drive system 40, and the open-side solenoid valve 41 opens, causing the clamp device 10 to perform a release operation.

[0029] In the following, the control performed by the controller 30 (release control unit 33) in response to the on / off state of the release permission switch 23, that is, the control that prohibits the release operation of the clamp device 10 when the release permission switch 23 is off, and permits the release operation of the clamp device 10 when the release permission switch 23 is on, will be referred to as "clamp release control".

[0030] In the forklift 1, if a tool (attachment) that does not perform object holding or release operations is attached, the user (such as a service technician) can disable the clamp release control by operating the touch panel 28 of the display device 27. In this case, the controller 30 (release control unit 33) performs processing to disable the clamp release control when it receives a signal from the touch panel 28 corresponding to the operation to disable the clamp release control. This prevents malfunctions such as the tool becoming inoperable due to the presence of the clamp release control when a tool that does not perform object holding or release operations is attached to the forklift 1.

[0031] Furthermore, in addition to the components described above, the forklift 1 has an abnormality detection sensor capable of detecting abnormalities such as wire breaks, ground faults, ceiling faults, and contact welding within the forklift 1, more specifically in the clamping device 10, etc. The controller 30 has a GND cut control unit configured to prohibit the supply of control signals from the solenoid control unit 32 to the open-side solenoid valve 41 and the closed-side solenoid valve 42 when the abnormality detection sensor detects an abnormality. In addition, a GND relay may be provided to stop the supply of current from the solenoid control unit 32 to the open-side solenoid valve 41 when the supply of control signals to the open-side solenoid valve 41 is prohibited by the GND cut control unit.

[0032] [Enable / Disable Determination of Release Permission Switch] Next, we will explain the determination (enabled / disabled determination) of whether the release permission switch 23 is enabled or disabled, which is performed by the controller 30 in this embodiment. First, we will explain the reason for performing the enabled / disabled determination of the release permission switch 23.

[0033] In a forklift 1 equipped with a clamping device 10 capable of holding and releasing objects, if the clamping device 10 accidentally performs a release operation while holding an object, the object will be dropped. Therefore, the forklift 1 is provided with a release permission switch 23 to allow or prohibit the release operation of the clamping device 10. This prevents accidental release of the work tool by allowing the release operation of the clamping device 10 only when the release permission switch 23 is on, and prohibiting the release operation of the clamping device 10 when the release permission switch 23 is off.

[0034] However, not all forklifts 1 are equipped with such a release permission switch 23, and some forklifts 1 do not have a release permission switch 23 (Figure 3 shows an example of a forklift 1 equipped with a release permission switch 23). Furthermore, even if a forklift 1 is equipped with a release permission switch 23, it may not be functioning effectively.

[0035] Therefore, it is necessary to configure whether or not the forklift 1 is equipped with a release permission switch 23, and in particular whether or not the release permission switch 23 is enabled on the forklift 1. Specifically, if the release permission switch 23 is enabled, it is necessary to configure the system so that clamp release control is performed. However, if such configuration is left to the user (such as an operator), it may not be configured correctly. For example, if the release permission switch 23 is equipped with a release permission switch 23 but is not configured, clamp release control will not be performed in response to the operator's operation of the release permission switch 23.

[0036] Based on the above, in this embodiment, the controller 30 determines whether the release permission switch 23 is enabled in the forklift 1 and makes settings according to the determination result. In other words, the determination of whether the release permission switch 23 is enabled and the setting are performed automatically within the forklift 1 without leaving it to the user.

[0037] Furthermore, the condition in which the release permission switch 23 is effective includes not only cases where the release permission switch 23 is installed on the forklift 1, but also conditions in which the release permission switch 23 can actually be made functional (i.e., conditions in which clamp release control can be achieved using the release permission switch 23). Conversely, the condition in which the release permission switch 23 is ineffective includes not only cases where the release permission switch 23 is not installed on the forklift 1, but also conditions in which the release permission switch 23 cannot actually be made functional (i.e., conditions in which clamp release control cannot be achieved using the release permission switch 23).

[0038] Next, with reference to Figure 5, the method for determining whether the release permission switch 23 is enabled or disabled according to this embodiment will be described. Figure 5 shows the relationship between the states (closed or open) of the first and second switches sw1 and sw2 of the release permission switch 23, indicated by the first and second input signals s1 and s2 supplied to the release control unit 33 of the controller 30, and the determination result of whether the release permission switch 23 is enabled or disabled based on these states.

[0039] Here, if the release permission switch 23 is enabled (for example, if the forklift 1 is equipped with a release permission switch 23), the first and second input signals s1 and s2 are signals from the first and second switches sw1 and sw2 of the release permission switch 23, that is, signals input from the first and second switches sw1 and sw2 to the controller 30. On the other hand, if the release permission switch 23 is disabled (for example, if the forklift 1 is not equipped with a release permission switch 23), the first and second input signals s1 and s2 are signals that the controller 30 receives, and are not signals from the first and second switches sw1 and sw2. In this case, the controller 30 receives a signal from an input terminal that is not connected to anything, that is, a signal from a disconnected wire (typically a signal where the current value / voltage value is approximately 0).

[0040] As shown in Figure 5, in this embodiment, the release control unit 33 of the controller 30 determines that the release permission switch 23 is not effective, i.e., disabled, when the first and second input signals s1 and s2 indicate that the states of the first and second switches sw1 and sw2 are the same. Specifically, the release control unit 33 determines that the release permission switch 23 is disabled when the first and second input signals s1 and s2 indicate that both the first and second switches sw1 and sw2 are open, or that both the first and second switches sw1 and sw2 are closed.

[0041] In the release-to-open switch 23, the common terminal 23c is selectively connected by the switch unit 23sw to either the normally closed terminal 23nc or the normally open terminal 23no (Figure 4). Therefore, in principle, one of the first and second switches sw1 and sw2 will be in a closed state, and the other in an open state. Consequently, if the release-to-open switch 23 is enabled, the states of the first and second switches sw1 and sw2 indicated by the first and second input signals s1 and s2 will not be the same. In other words, if the states indicated by the first and second input signals s1 and s2 are the same, it indicates that the release-to-open switch 23 is disabled. Typically, when the release-to-open switch 23 is disabled, the release control unit 33 of the controller 30 receives a signal from an input terminal that is not connected to anything, that is, a signal from a disconnected wire. This signal is the same as when the first and second switches sw1 and sw2 are in an open state (a signal where the current value / voltage value is approximately 0). Based on the above, the release control unit 33 determines that the release permission switch 23 is abnormal if the states of the first and second switches sw1 and sw2, indicated by the first and second input signals s1 and s2, are the same.

[0042] On the other hand, the release control unit 33 determines that the release enable switch 23 is enabled if the states of the first and second switches sw1 and sw2 indicated by the first and second input signals s1 and s2 are different. Specifically, the release control unit 33 determines that the release enable switch 23 is enabled if the first input signal s1 indicates that the first switch sw1 is closed and the second input signal s2 indicates that the second switch sw2 is open. In this case, the release enable switch 23 is in the off state. Also, the release control unit 33 determines that the release enable switch 23 is enabled if the first input signal s1 indicates that the first switch sw1 is open and the second input signal s2 indicates that the second switch sw2 is closed. In this case, the release enable switch 23 is in the on state.

[0043] In addition, some forklifts 1 are equipped with two or more (typically two) release permission switches 23. In such cases, the controller 30 can determine whether the release permission switches 23 are enabled or disabled based on first and second input signals s1 and s2, which may include signals from each release permission switch 23. The controller 30 then determines that at least one release permission switch 23 is enabled in the forklift 1 and makes settings according to that determination.

[0044] Next, with reference to Figure 6, the overall flow of the control performed in this embodiment will be described. Figure 6 is a flowchart of the control method according to this embodiment. This flow is repeatedly executed by the controller 30 at a predetermined period (for example, a 10ms period). Specifically, the processor 31 in the controller 30 reads a program stored in the memory 35 and executes the program, thereby realizing the control and processing related to this flow.

[0045] First, in step S10, the controller 30 acquires various information necessary for executing this flow. Specifically, the controller 30 acquires at least the first and second input signals s1 and s2 input to the release control unit 33, and reads the information stored in the memory 35 (especially ROM) (hereinafter simply referred to as "stored value") regarding the results of the enable / disable determination of the release permission switch 23 that has been performed so far.

[0046] Next, in step S11, the controller 30 determines whether or not the stored value of the enable / disable determination result in step S10 was acquired, that is, whether or not the stored value is stored in memory 35. In particular, it determines whether or not the enable / disable determination of the release permission switch 23 has been performed up to this point. If, as a result of step S11, the controller 30 determines that the stored value was not acquired in step S10 (step S11: Yes), it proceeds to step S12. This corresponds to a case where the enable / disable determination of the release permission switch 23 has not been performed up to this point, typically such as when the forklift 1 is shipped from the factory, that is, when the first key switch of the forklift 1 is turned on or when the forklift 1 is first turned on.

[0047] From step S12 onward, the controller 30 performs actions such as determining whether the release-to-enabled switch 23 is enabled or disabled. First, in step S12, the controller 30 starts counting on the determination timer. This determination timer is used to repeatedly determine whether the release-to-enabled switch 23 is enabled or disabled for a predetermined period of time. The reason for repeating the enable / disable determination for a predetermined period of time is to counteract noise contained in the first and second input signals s1 and s2. In other words, it is to prevent misjudgments caused by fluctuations in the values ​​of the first and second input signals s1 and s2 due to noise.

[0048] Next, in step S13, the controller 30 determines whether the release enable switch 23 is enabled or disabled. Specifically, the controller 30 first compares the states of the first and second switches sw1 and sw2, respectively, as indicated by the acquired first and second input signals s1 and s2. The controller 30 then determines that the release enable switch 23 is enabled if the states of the first and second switches sw1 and sw2, as indicated by the first and second input signals s1 and s2, are different, while determining that the release enable switch 23 is disabled if the states of the first and second switches sw1 and sw2, as indicated by the first and second input signals s1 and s2, are the same (Figure 5).

[0049] Next, in step S14, the controller 30 repeatedly performs the enable / disable determination at a predetermined cycle (until the determination timer reaches a predetermined time) and determines whether the result of the enable / disable determination performed in step S13 is the same as the result of the enable / disable determination performed in the previous step S13. If the controller 30 does not determine that the determination results are the same (step S14: No), that is, if the determination results are different, it proceeds to step S17, clears the determination timer, and then exits the flow shown in Figure 6. In this case, the controller 30 recounts the determination timer to eliminate the influence of noise on the first and second input signals s1 and s2, and performs a new enable / disable determination of the release enable switch 23.

[0050] In response, if the controller 30 determines that the judgment results are the same (step S14: Yes), it proceeds to step S15. In step S15, the controller 30 determines whether the judgment timer has reached a predetermined time (e.g., 0.2 seconds). If the controller 30 does not determine that the judgment timer has reached the predetermined time (step S15: No), it returns to step S13. In this case, the controller 30 repeats steps S13 to S15 until the judgment timer reaches the predetermined time. In response, if the controller 30 determines that the judgment timer has reached the predetermined time (step S15: Yes), it proceeds to step S16.

[0051] In step S16, the controller 30 stores the determination result of whether the release permission switch 23 is enabled or disabled in the memory 35. For example, the controller 30 writes the determination result to the ROM of the memory 35. The controller 30 also makes settings according to this determination result. Specifically, if the controller 30 determines that the release permission switch 23 is enabled, it configures the release control unit 33 so that clamp release control is performed to enable or disable the release operation of the clamp device 10 in response to the on / off operation of the release permission switch 23. Conversely, if the controller 30 determines that the release permission switch 23 is disabled, it configures the release control unit 33 to disable clamp release control. After this, the controller 30 exits the flow shown in Figure 6.

[0052] On the other hand, if, as a result of step S11, the controller 30 does not determine that the memory value was not acquired in step S10 (step S11: No), that is, if the memory value of the determination result of whether the release enable switch 23 is enabled or disabled is stored in memory 35, the process proceeds to step S18. In step S18, the controller 30 determines whether the release enable switch 23 is enabled or disabled based on the acquired first and second input signals s1 and s2, using the same procedure as in step S13 above.

[0053] Next, in step S19, the controller 30 determines whether the result of the determination in step S18 is the same as the result of the determination indicated by the stored value in memory 35. If the controller 30 determines that the result of the determination in step S18 is the same as the result of the determination indicated by the stored value (step S19: Yes), it exits the flow shown in Figure 6 without performing any processing or control.

[0054] In response, if the controller 30 does not determine that the result of the determination in step S18 is the same as the determination result indicated by the stored value (step S19: No), that is, if the determination results are different, it proceeds to step S20. In this case, it is possible that, for example, an abnormality has occurred in the memory 35. Therefore, in step S20, the controller 30 disables the operation of the clamping device 10 in order to deal with such an abnormality and ensure the safety of the forklift 1. After this, the controller 30 exits the flow shown in Figure 6.

[0055] Furthermore, if the determination result in step S18 differs from the determination result indicated by the stored value, step S20 is not limited to prohibiting the operation of the clamp device 10. In other examples, the controller 30 may, similar to step S16 above, newly store the determination result from step S18 in the memory 35 (i.e., update the stored value in memory 35) and make settings according to this determination result. For example, if the controller 30 obtains a new determination result indicating that the release permission switch 23 is valid, it may store this determination result in the memory 35 and set the release control unit 33 so that clamp release control is performed.

[0056] [Mechanism of Action and Effects] Next, the operation and effects of the forklift 1 according to this embodiment will be described. In this embodiment, the forklift 1 has a main body 2 and a work machine 3 to which a clamping device 10, which is disposed on the main body 2 and can be attached, performs a holding operation for holding an object and a releasing operation for releasing the held object. The forklift 1 has an operating lever 21 that is operated by an operator to operate the clamping device 10, a drive system 40 configured to drive the clamping device 10 to operate the clamping device 10, and a controller 30 configured to control the drive system 40 so as to operate the clamping device 10 in response to the operation of the operating lever 21. The controller 30 receives first and second input signals s1 and s2, including a signal from a release permission switch 23 for permitting or prohibiting the release operation of the clamping device 10, and determines whether the release permission switch 23 is enabled in the forklift 1 based on the first and second input signals s1 and s2, and makes settings according to the determination result.

[0057] According to this embodiment, the determination and setting of whether or not the release permission switch 23 is enabled can be performed automatically and accurately within the forklift 1. Therefore, problems that would occur if such settings were left to the user can be prevented. For example, problems such as the clamp release control not being performed in response to the operation of the release permission switch 23 because the release permission switch 23 is enabled but its setting is not made correctly, or problems that occur as a result of the clamp release control not being performed can be avoided.

[0058] Furthermore, in this embodiment, the release permission switch 23 includes first and second switches sw1 and sw2 which are switched on and off to allow or prohibit the release operation of the clamp device 10, and whose respective states switch depending on whether the release permission switch 23 is on or off, and the first and second input signals s1 and s2 can correspond to signals from the first and second switches sw1 and sw2, and the controller 30 is configured to determine whether the release permission switch 23 is enabled or not based on the relationship between the first and second input signals s1 and s2.

[0059] In this embodiment, the release permission switch 23 is configured with two first and second switches sw1 and sw2, whose respective states (open state / closed state) switch depending on whether the switch is on or off. First and second input signals s1 and s2, which may include signals from these first and second switches sw1 and sw2, are supplied to the controller 30. As a result, the controller 30 can accurately determine whether the release permission switch 23 is enabled or disabled based on the relationship between the first and second input signals s1 and s2.

[0060] Furthermore, in this embodiment, the release permission switch 23 includes a normally closed first switch sw1 and a normally open second switch sw2. The controller 30 is configured to determine that the release permission switch 23 is effective when the first and second input signals s1 and s2 indicate that the first and second switches sw1 and sw2 are in different states, while determining that the release permission switch 23 is not effective when the first and second input signals s1 and s2 indicate that the first and second switches sw1 and sw2 are in the same state.

[0061] In the release-to-enable switch 23, which consists of a normally closed first switch sw1 and a normally open second switch sw2, in principle, one of the first and second switches sw1 and sw2 will be in a closed state (connected state), and the other will be in an open state (disconnected state / unconnected state). Therefore, if the states of the first and second switches sw1 and sw2 indicated by the first and second input signals s1 and s2 are different, it means that the release-to-enable switch 23 is active. Conversely, if the states of the first and second switches sw1 and sw2 indicated by the first and second input signals s1 and s2 are the same, it means that the release-to-enable switch 23 is inactive. Thus, by making a determination based on the states of the first and second switches sw1 and sw2 indicated by the first and second input signals s1 and s2, it is possible to accurately determine whether the release-to-enable switch 23 is active or inactive.

[0062] Furthermore, in this embodiment, the controller 30 stores the determination result of whether or not the release permission switch 23 is enabled, compares the stored determination result (stored value) with the determination result of whether or not the release permission switch 23 is enabled after this storage, and is configured to prohibit the operation of the clamping device 10 if these determination results are different. This ensures the safety of the forklift 1, for example, if an abnormality occurs in the memory 35 that stores the determination result.

[0063] Furthermore, in this embodiment, the controller 30 is configured to repeatedly determine whether the release permission switch 23 is enabled or disabled for a predetermined period of time, and if the same determination result is obtained for the predetermined period of time, it sets the parameters according to that determination result. This prevents misdetermination due to noise contained in the first and second input signals s1 and s2.

[0064] Furthermore, in this embodiment, the controller 30 is configured to, when it determines that the release permission switch 23 is active, to set the drive system 40 to allow or prohibit the release operation of the clamp device 10 depending on whether the release permission switch 23 is on or off. This makes it possible to accurately set the clamp release control that is achieved by operating the release permission switch 23 when the release permission switch 23 is active.

[0065] Furthermore, in this embodiment, the main body 2 includes a traveling body 2R, and the traveling body 2R is configured to be driven and controlled independently of the work machine 3, which includes the clamping device 10. In a forklift 1 including such a traveling body 2R, if the release permission switch 23 is not set correctly and clamp release control is not performed, the object will fall off while traveling if the clamping device 10 mistakenly performs a release operation. However, according to this embodiment, since the determination and setting of the release permission switch 23 are performed correctly as described above, such problems can be reliably avoided.

[0066] [Differentiation] Next, a modified example of the above-described embodiment will be explained.

[0067] In the embodiments described above, the present invention was applied to a forklift 1 having a clamping device 10. However, the present invention is applicable to various work machines to which work tools (attachments) that perform object holding and release operations can be attached. For example, the present invention is applicable to hydraulic excavators, log loaders, wheel loaders, and the like.

[0068] Furthermore, while the present invention was applied to a work machine (forklift 1) in the above-described embodiment, in a modified example, the present invention may also be applied to a control system for a work machine configured to allow an operator to operate the work machine from the outside, where the operating device (remote control) of the work machine is located externally, or to a control system for a work machine configured to allow operation of the work machine by operation commands from an external controller such as a control system.

[0069] As described above, the embodiments and modifications described are illustrative examples for explaining the present invention, and the present invention is not limited to these embodiments and modifications. The present invention can be implemented in various forms without departing from its spirit.

[0070] (Note 1) The main unit and A work tool that is operable with respect to the main body and performs a holding operation for holding an object and a releasing operation for releasing the held object, An operating device that receives commands to operate the aforementioned work tool, A drive system for operating the aforementioned work tool, A controller configured to control the drive system to operate the work tool in response to the operation of the operating device, It has, The aforementioned controller, The system receives an input signal including a signal from a release permission switch for permitting or prohibiting the release operation of the aforementioned work tool. When the release permission switch is enabled in the aforementioned work machine, the settings related to the release permission switch are made. A work machine configured in such a way. (Note 2) The release permission switch includes a plurality of switches that are switched on and off to allow or prohibit the release operation of the work tool, and whose respective states switch depending on whether the release permission switch is switched on or off. The input signal includes a plurality of signals that can correspond to signals from the plurality of switches, and the controller is configured to determine whether the release enable switch is enabled or disabled based on the relationship between the plurality of signals. The work machines described in Appendix 1. (Note 3) The plurality of switches include normally open type switches and normally closed type switches, where when one is closed, the other is open, and they have different output characteristics. The controller is configured to determine that the release enable switch is enabled if the multiple signals indicate that the multiple switches are in different states, while determining that the release enable switch is disabled if the multiple signals indicate that the multiple switches are in the same state. The work machines described in Appendix 2. (Note 4) The controller is configured to store the result of determining whether the release permission switch is enabled or disabled, compare the stored result with the result of determining whether the release permission switch is enabled or disabled after the storage, and prohibit the operation of the work tool if the results of these determinations are different, as described in any of Appendix 1 to 3. (Note 5) The controller is configured to repeatedly determine whether the release permission switch is enabled or disabled for a predetermined period of time, and if the same determination result is obtained for the predetermined period of time, to make a setting according to that determination result, as described in any of the appendices 1 to 4. (Note 6) The work machine according to any one of the appendices 1 to 5, wherein the controller is configured to set the drive system to allow or prohibit the release operation of the work tool in accordance with whether the release permission switch is turned on or off, when it determines that the release permission switch is valid. (Note 7) The work machine described in any one of the appendices 1 to 6, wherein the work machine comprises a work machine disposed on the main body and including the work tool, the main body includes a traveling body, and the traveling body is configured to be driven and controlled independently of the work tool. (Note 8) The work machine is a forklift, and the work tool is a clamping device for the forklift, as described in any one of Appendix 1 to 7. (Note 9) The main unit and A work tool that is operable with respect to the main body and performs a holding operation for holding an object and a releasing operation for releasing the held object, An operating device that receives commands to operate the aforementioned work tool, A drive system for operating the aforementioned work tool, A controller configured to control the drive system to operate the work tool in response to the operation of the operating device, It has, The aforementioned controller, The system receives an input signal including a signal from a release permission switch for permitting or prohibiting the release operation of the aforementioned work tool. When the release permission switch is enabled in the aforementioned work machine, the settings related to the release permission switch are made. A control system for a work machine configured in such a way. (Note 10) A work machine comprising a main body, a work tool that is operable relative to the main body and performs a holding operation for holding an object and a releasing operation for releasing the held object, an operating device that receives an operation for operating the work tool, and a drive system for operating the work tool, wherein a control method for the work machine is performed by a controller for operating the work machine, Controlling the drive system to operate the work tool in response to the operation of the operating device, The system receives an input signal including a signal from a release permission switch for permitting or prohibiting the release operation of the aforementioned work tool, When the release permission switch is enabled in the aforementioned work machine, the settings related to the release permission switch are to be made. A method for controlling a work machine equipped with a machine. [Explanation of Symbols]

[0071] 1...Forklift, 2...Main body, 2R...Travel body, 3...Work equipment, 5...Mast, 10...Clamping device, 21...Operating lever, 23...Release permission switch, 23c...Common terminal, 23nc...Normally closed terminal, 23no...Normally open terminal, 23sw...Switch unit, 27...Display device, 30...Controller, 31...Processor, 32...Solenoid control unit, 33...Release control unit, 40...Drive system, 41...Open solenoid valve, 42...Closed solenoid valve, 44...Hydraulic drive device, s1...First input signal, s2...Second input signal, sw1...First switch, sw2...Second switch

Claims

1. The main unit and A work tool that is operable with respect to the main body and performs a holding operation for holding an object and a releasing operation for releasing the held object, An operating device that receives commands to operate the aforementioned work tool, A drive system for operating the aforementioned work tool, A controller configured to control the drive system to operate the work tool in response to the operation of the operating device, It has, The aforementioned controller, The system receives an input signal including a signal from a release permission switch for permitting or prohibiting the release operation of the aforementioned work tool. When the release permission switch is enabled in the aforementioned work machine, the settings related to the release permission switch are made. A work machine configured in such a way.

2. The release permission switch includes a plurality of switches that are switched on and off to allow or prohibit the release operation of the work tool, and whose respective states switch depending on whether the release permission switch is switched on or off. The input signal includes a plurality of signals that can correspond to signals from the plurality of switches, and the controller is configured to determine whether the release enable switch is enabled or disabled based on the relationship between the plurality of signals. The work machine according to claim 1.

3. The plurality of switches include normally open type switches and normally closed type switches, where when one is closed, the other is open, and they have different output characteristics. The controller is configured to determine that the release enable switch is enabled if the multiple signals indicate that the multiple switches are in different states, while determining that the release enable switch is disabled if the multiple signals indicate that the multiple switches are in the same state. The working machine according to claim 2.

4. The controller is configured to store a determination result of whether the release permission switch is enabled or disabled, compare the stored determination result with a determination result of whether the release permission switch is enabled or disabled made after the storage, and prohibit the operation of the work tool if the determination results are different, as described in claim 1 or 2.

5. The work machine according to claim 1 or 2, wherein the controller is configured to repeatedly determine whether the release permission switch is enabled or disabled for a predetermined period of time, and if the same determination result is obtained for the predetermined period of time, to make a setting according to that determination result.

6. The work machine according to claim 1 or 2, wherein the controller is configured to, when it determines that the release permission switch is valid, to set the drive system to allow or prohibit the release operation of the work tool in accordance with whether the release permission switch is turned on or off.

7. The work machine according to claim 1 or 2, wherein the work machine comprises a work machine disposed on the main body and including the work tool, the main body includes a traveling body, and the traveling body is configured to be driven and controlled independently of the work tool.

8. The work machine according to claim 1 or 2, wherein the work machine is a forklift, and the work tool is a clamping device for the forklift.

9. The main unit and A work tool that is operable with respect to the main body and performs a holding operation for holding an object and a releasing operation for releasing the held object, An operating device that receives commands to operate the aforementioned work tool, A drive system for operating the aforementioned work tool, A controller configured to control the drive system to operate the work tool in response to the operation of the operating device, It has, The aforementioned controller, The system receives an input signal including a signal from a release permission switch for permitting or prohibiting the release operation of the aforementioned work tool. When the release permission switch is enabled in the aforementioned work machine, the settings related to the release permission switch are made. A control system for a work machine configured in such a way.

10. A work machine comprising a main body, a work tool that is operable relative to the main body and performs a holding operation for holding an object and a releasing operation for releasing the held object, an operating device that receives an operation for operating the work tool, and a drive system for operating the work tool, wherein a control method for the work machine is performed by a controller for operating the work machine, Controlling the drive system to operate the work tool in response to the operation of the operating device, The system receives an input signal including a signal from a release permission switch for permitting or prohibiting the release operation of the aforementioned work tool, When the release permission switch is enabled in the aforementioned work machine, the settings related to the release permission switch are to be made. A method for controlling a work machine equipped with a machine.

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