Working machine

Abstract

To provide a working machine capable of detecting failure of a boom connection mechanism or a cylinder connection mechanism.SOLUTION: A working machine includes an electric coupling mechanism including a telescopic boom that includes a plurality of booms and is extended and contracted by a telescopic cylinder, a cylinder coupling mechanism that couples the boom and the telescopic cylinder and releases coupling between the boom and the telescopic cylinder by a motor, and a boom coupling mechanism that couples adjacent booms and releases coupling between the adjacent booms by the motor, and a control unit that controls an operation of the electric coupling mechanism, in which the control unit performs inspection control for checking the operation of the electric coupling mechanism.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a work machine equipped with a telescopic boom. [Background technology]

[0002] Patent Document 1 discloses a mobile crane equipped with a telescopic boom in which multiple booms are nested one on top of the other, and a hydraulic actuator (telescopic cylinder) that extends the telescopic boom.

[0003] Adjacent booms are connected to each other by a boom connecting pin. A boom that has been released from the connection by the boom connecting pin (hereinafter referred to as a movable boom) becomes movable in the extension / retraction direction relative to the other booms.

[0004] The actuator is connected to the movable boom via a cylinder connecting pin. When the actuator moves in the extension / retraction direction, the movable boom moves together with the actuator, and the telescopic boom extends or retracts. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-96928 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, the above-described crane includes a boom connecting mechanism that displaces the boom connecting pin, and a cylinder connecting mechanism that displaces the cylinder connecting pin.

[0007] In recent years, cranes have been developed that include an electric coupling mechanism that has a boom coupling mechanism and a cylinder coupling mechanism that operate based on the power of an electric motor. In such cranes, if a malfunction occurs in the electric coupling mechanism, it is desirable to be able to quickly detect the malfunction.

[0008] An object of the present invention is to provide a work machine that can detect an abnormality in an electric connecting mechanism. [Means for solving the problem]

[0009] One aspect of the working machine according to the present invention is a telescopic boom having a plurality of booms and extending and retracting by a telescopic cylinder; an electric coupling mechanism including a cylinder coupling mechanism that couples the boom to the telescopic cylinder and releases the connection between the boom and the telescopic cylinder by a motor, and a boom coupling mechanism that couples adjacent booms together and releases the connection between the adjacent booms by a motor; a control unit that controls the operation of the electric coupling mechanism, The control unit performs inspection control to check the operation of the electric coupling mechanism. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a work machine that is capable of detecting an abnormality in an electric connecting mechanism. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a mobile crane according to an embodiment of the present invention. [Figure 2A] FIG. 2A is a schematic diagram for explaining the structure and extension / retraction operation of a telescopic boom. [Figure 2B] FIG. 2B is a schematic diagram for explaining the structure and extension / retraction operation of the telescopic boom. [Figure 2C] FIG. 2C is a schematic diagram for explaining the structure and extension / retraction operation of the telescopic boom. [Figure 2D] FIG. 2D is a schematic diagram for explaining the structure and extension / retraction operation of the telescopic boom. [Figure 2E] FIG. 2E is a schematic diagram for explaining the structure and extension / retraction operation of the telescopic boom. [Figure 3A] FIG. 3A is a schematic diagram for explaining the operation of the cylinder coupling mechanism. [Figure 3B] FIG. 3B is a schematic diagram for explaining the operation of the cylinder coupling mechanism. [Figure 3C] FIG. 3C is a schematic diagram for explaining the operation of the cylinder coupling mechanism. [Figure 4A] FIG. 4A is a schematic diagram for explaining the operation of the boom connecting mechanism. [Figure 4B] FIG. 4B is a schematic diagram for explaining the operation of the boom connection mechanism. [Figure 4C] FIG. 4C is a schematic diagram for explaining the operation of the boom connection mechanism. [Figure 5] FIG. 5 is a flowchart of the inspection control. [Figure 6] FIG. 6 is a flowchart of the motor inspection control in the inspection control. [Figure 7] FIG. 7 is a flowchart of the brake inspection control in the inspection control. [Figure 8] FIG. 8 is a flowchart of the entrance operation inspection control in the inspection control. DETAILED DESCRIPTION OF THE INVENTION

[0012] An example of an embodiment of the present invention will be described in detail below with reference to the drawings. Note that the crane according to the embodiment described below is an example of a work machine according to the present invention, and the present invention is not limited to the embodiment described below.

[0013] [Embodiment] A mobile crane 1 according to an embodiment of the present invention will be described with reference to Figures 1 to 8. First, an overview of the mobile crane 1 according to an embodiment of the present invention will be described with reference to Figures 1 and 2A to 2E.

[0014] Examples of mobile cranes include rough terrain cranes, all-terrain cranes, truck cranes, and loaded truck cranes. However, the work machine is not limited to a mobile crane and may be another work machine (e.g., an aerial work platform) equipped with a telescopic boom.

[0015] The mobile crane 1 has a telescopic boom 14 and an actuator 2. The telescopic boom 14 has multiple booms combined so that they can be extended and retracted. Adjacent booms are connected to each other by boom connecting pins (boom connecting pins 144a, 144b).

[0016] When extending or retracting the telescopic boom 14, the actuator 2 moves the boom in the extension / retraction direction. At this time, the actuator 2 connects to the boom to be moved via the cylinder connecting pins 454A, 454B, and releases the connection between the boom to be moved and the boom adjacent to the boom to be moved.

[0017] As shown in FIGS. 1 and 2A to 2E, the mobile crane 1 includes a traveling body 10, a swivel base 12, a telescopic boom 14, an actuator 2, a wire rope 16, and a hook 17.

[0018] The swivel base 12 is rotatably provided on the upper part of the traveling body 10. The telescopic boom 14 has multiple booms (for example, a tip boom 141, an intermediate boom 142, and a base boom 143, which will be described later) and is extended and retracted by the telescopic cylinder 3.

[0019] The base end of the telescopic boom 14 is fixed to the swivel base 12 and is capable of raising and lowering. The actuator 2 extends and lowers the telescopic boom 14. A wire rope 16 is supported by the telescopic boom 14 and hangs down from the tip of the telescopic boom 14. A hook 17 is attached to the tip of the wire rope 16.

[0020] Next, the telescopic boom 14 will be described with reference to Figures 1 and 2A to 2E. The telescopic boom 14 has multiple booms combined in a telescopic manner. Specifically, the multiple booms are, in order from the inside, a tip boom 141, an intermediate boom 142, and a base boom 143.

[0021] The telescopic boom 14 extends in order from the innermost boom, thereby transitioning from the contracted state shown in Fig. 2A to the extended state shown in Fig. 1. Note that there may be multiple intermediate booms.

[0022] The tip boom 141 is cylindrical and has an internal space capable of accommodating the actuator 2. The tip boom 141 has, at its base end, a pair of cylinder pin receiving portions 1411, 1412 and a pair of boom pin receiving portions 141b. The pair of cylinder pin receiving portions 1411, 1412 and the pair of boom pin receiving portions 141b are each a through hole.

[0023] The pair of cylinder pin receivers 1411, 1412 are coaxially provided at the base end of the tip boom 141. The pair of cylinder pin receivers 1411, 1412 are respectively engageable with and disengageable from a pair of cylinder connecting pins 454A, 454B provided on the cylinder member 32 of the telescopic cylinder 3.

[0024] The cylinder connecting pins 454A, 454B are each an example of a first pin, and are biased outward (in the direction from the base end toward the tip end of the cylinder connecting pins 454A, 454B) by a first biasing mechanism 455 (described later). The cylinder connecting pins 454A, 454B move inward (in the direction from the tip end toward the base end of the cylinder connecting pins 454A, 454B) based on the operation of a cylinder connecting mechanism 45 (described later).

[0025] With the cylinder connecting pins 454A, 454B engaged with the pair of cylinder pin receiving portions 1411, 1412, the tip boom 141 can move together with the cylinder member 32 in the extension / contraction direction.

[0026] The pair of boom pin receiving portions 141b are provided coaxially around the cylinder pin receiving portions 1411, 1412. The boom pin receiving portions 141b are respectively engageable with and disengageable from the pair of boom connecting pins 144a. For ease of explanation, in the drawings, the pair of boom pin receiving portions 141b and the pair of cylinder pin receiving portions 1411, 1412 are shown misaligned in the axial direction of the telescopic boom 14.

[0027] In reality, the pair of boom pin receiving portions 141b and the pair of cylinder pin receiving portions 1411, 1412 are aligned in the axial direction of the telescopic boom 14 and are provided at offset positions in the circumferential direction of the telescopic boom 14.

[0028] Each of the pair of boom connecting pins 144a corresponds to an example of a second pin, and is biased outward (in the direction from the base end toward the tip end of the boom connecting pin 144a) by a second biasing mechanism 463 described below. Each of the pair of boom connecting pins 144a connects the tip boom 141 and the intermediate boom 142. The pair of boom connecting pins 144a move inward (in the direction from the tip end toward the base end of the boom connecting pin 144a) based on the operation of a boom connecting mechanism 46 described below.

[0029] With the tip boom 141 and the intermediate boom 142 connected by a pair of boom connecting pins 144a, the boom connecting pin 144a is inserted so as to span between the boom pin receiving portion 141b of the tip boom 141 and the first boom pin receiving portion 142b or the second boom pin receiving portion 142c of the intermediate boom 142.

[0030] When the tip boom 141 and the intermediate boom 142 are connected, the tip boom 141 is prohibited from moving relative to the intermediate boom 142. On the other hand, when the tip boom 141 and the intermediate boom 142 are not connected, the tip boom 141 is movable relative to the intermediate boom 142.

[0031] The intermediate boom 142 is cylindrical and has an internal space capable of accommodating the tip boom 141. The intermediate boom 142 has a pair of cylinder pin receiving portions 142a, a pair of first boom pin receiving portions 142b, and a pair of third boom pin receiving portions 142d at its base end, and a pair of second boom pin receiving portions 142c at its tip end. The pair of cylinder pin receiving portions 142a, the pair of first boom pin receiving portions 142b, the pair of third boom pin receiving portions 142d, and the pair of second boom pin receiving portions 142c are each a through hole.

[0032] The pair of cylinder pin receiving portions 142a and the pair of first boom pin receiving portions 142b are substantially similar to the pair of cylinder pin receiving portions 1411, 1412 and the pair of boom pin receiving portions 141b of the tip boom 141, respectively.

[0033] For ease of explanation, the illustration shows the pair of first boom pin receiving portions 142b and the pair of cylinder pin receiving portions 142a as being offset in the axial direction of the telescopic boom 14. In reality, the pair of first boom pin receiving portions 142b and the pair of cylinder pin receiving portions 142a are aligned in the axial direction of the telescopic boom 14 and are provided at offset positions in the circumferential direction of the telescopic boom 14.

[0034] The pair of third boom pin receiving portions 142d are provided coaxially with each other and closer to the base end than the pair of first boom pin receiving portions 142b. A pair of boom connecting pins 144b are inserted into the pair of third boom pin receiving portions 142d, respectively. The pair of boom connecting pins 144b connect the intermediate boom 142 and the base boom 143.

[0035] The pair of second boom pin receiving portions 142c are provided coaxially with each other at the tip of the intermediate boom 142. A pair of boom connecting pins 144a are inserted into the pair of second boom pin receiving portions 142c, respectively.

[0036] The actuator 2 is an actuator that extends and retracts the telescopic boom 14. As shown in FIGS. 2A to 4C, the actuator 2 has a telescopic cylinder 3 and a pin moving mechanism 4. The actuator 2 is disposed in the internal space of the tip boom 141 when the telescopic boom 14 is in the retracted state (the state shown in FIG. 2A).

[0037] The telescopic cylinder 3 is an example of an extension device and includes a rod member 31 and a cylinder member 32. The telescopic cylinder 3 moves a boom connected to the cylinder member 32 via cylinder connecting pins 454A and 454B, which will be described later.

[0038] The pin moving mechanism 4 is an example of an electric coupling mechanism and includes an electric motor 41, a brake mechanism 42, a transmission mechanism 43, a cylinder coupling mechanism 45, a boom coupling mechanism 46, a switching mechanism 47, and a position information detection device 48, all of which are supported by a trunnion (not shown).

[0039] Hereinafter, each member constituting the actuator 2 will be described based on the state in which each member is incorporated into the actuator 2.

[0040] The trunnion (not shown) is fixed to the cylinder member 32 of the telescopic cylinder 3. Therefore, the pin moving mechanism 4 is supported by the cylinder member 32 of the telescopic cylinder 3. The pin moving mechanism 4 moves together with the cylinder member 32 in the extension / retraction direction of the telescopic boom 14 (in other words, in the axial direction of the telescopic boom 14). The cylinder member 32 is an example of a movable part of an actuator.

[0041] Such a trunnion unitizes the above-mentioned elements that make up the pin moving mechanism 4. Such a configuration contributes to a smaller size of the pin moving mechanism 4, improved productivity, and improved system reliability.

[0042] The electric motor 41 is, for example, a brushed DC motor or a brushless motor. The electric motor 41 is supported by a trunnion (not shown). As shown in FIGS. 3A to 4C, the electric motor 41 is connected to a reducer 431. The electric motor 41 is connected to, for example, a power supply device (not shown) provided on the swivel base 12 via a power supply cable.

[0043] The brake mechanism 42 is a so-called electromagnetic brake, and applies a braking force to the electric motor 41. The brake mechanism 42 prevents the rotation of the output shaft of the electric motor 41 when the electric motor 41 is stopped. This maintains the state of the pin moving mechanism 4 when the electric motor 41 is stopped.

[0044] The brake mechanism 42 is connected via a power supply cable to, for example, a power supply device (not shown) provided on the swivel base 12. Note that a position information detection device 48 (described later) is also connected via a power supply cable to, for example, a power supply device (not shown) provided on the swivel base 12.

[0045] Specifically, the brake mechanism 42 operates when the cylinder coupling mechanism 45 or the boom coupling mechanism 46, which will be described later, is in a contracted state, to maintain the states of the cylinder coupling mechanism 45 and the boom coupling mechanism 46. The state of the brake mechanism 42 is switched by a control unit (not shown). Alternatively, the state of the brake mechanism 42 may be switched based on an operation by an operator. The operation of the brake mechanism 42 will be described later.

[0046] The transmission mechanism 43 transmits the power of the electric motor 41 to the cylinder connecting mechanism 45 and the boom connecting mechanism 46. The transmission mechanism 43 includes a reducer 431 and a transmission shaft 432.

[0047] The reducer 431 reduces the rotation of the electric motor 41 and transmits the reduced rotation to a transmission shaft 432. The transmission shaft 432 transmits the rotation of the reducer 431 to a switching mechanism 47, which will be described later. In addition, a position information detection device 48 is provided at the tip of the transmission shaft 432, which detects information relating to the positions of the cylinder connecting pins 454A, 454B and the pair of boom connecting pins 144a, 144b.

[0048] The information relating to the positions of the cylinder connecting pins 454A, 454B and the pair of boom connecting pins 144a, 144b is, for example, the rotation angle of the electric motor 41 (specifically, the rotation angle of the transmission shaft 432). The rotation angle of the electric motor 41 (specifically, the rotation angle of the transmission shaft 432) corresponds to the amount of movement of the cylinder connecting pins 454A, 454B or the pair of boom connecting pins 144a, 144b from a reference position.

[0049] The positions of the cylinder connecting pins 454A, 454B shown in Fig. 3A are the reference positions of the cylinder connecting pins 454A, 454B. Also, the positions of the pair of boom connecting pins 144a shown in Fig. 4A are the reference positions of the boom connecting pins 144a.

[0050] The switching mechanism 47 is selectively connected to one of a cylinder connecting mechanism 45 and a boom connecting mechanism 46, which will be described later, and transmits the power of the electric motor 41 to one of the connecting mechanisms.

[0051] The switching mechanism 47 has a switch gear 471. The switch gear 471 is fitted and fixed to the outside of the transmission shaft 432, and selectively transmits the power of the electric motor 41 to either the cylinder connection mechanism 45 or the boom connection mechanism 46.

[0052] Here, the rotation direction of the switch gear 471 when the cylinder coupling mechanism 45 transitions from the extended state to the contracted state (the direction indicated by the arrow A1 in FIGS. 3A to 3C) is defined as a first rotation direction of the switch gear 471. Also, the rotation direction of the switch gear 471 when the cylinder coupling mechanism 45 transitions from the contracted state to the extended state (the direction indicated by the arrow A2 in FIGS. 3A to 3C) is defined as a second rotation direction of the switch gear 471.

[0053] The first rotation direction A1 of the switch gear 471 is also the rotation direction of the switch gear 471 when the boom connection mechanism 46 transitions from the retracted state (see FIG. 4C) to the extended state (see FIG. 4A). The second rotation direction A2 of the switch gear 471 is also the rotation direction of the switch gear 471 when the boom connection mechanism 46 transitions from the extended state (see FIG. 4A) to the retracted state (see FIG. 4C).

[0054] Furthermore, the position information detection device 48 is connected to a control unit 50 (see FIGS. 3A to 4C) provided on the swivel base 12 via a signal transmission cable. The power supply cable to the electric motor 41, the power supply cable to the brake mechanism 42, the power supply cable to the position information detection device 48, and the signal transmission cable of the position information detection device 48 are all combined into a single multi-core cable and arranged in the interior space of the telescopic boom 14. With this configuration, the interior space of the telescopic boom 14 can be used efficiently.

[0055] The cylinder coupling mechanism 45 is an example of a first coupling mechanism, which couples the boom with the telescopic cylinder 3 and releases the coupling using a motor. Specifically, the cylinder coupling mechanism 45 operates based on the power of the electric motor 41 under the control of the controller 50, and transitions between an extended state (see FIG. 3A) and a retracted state (see FIG. 3C).

[0056] 3A to 3C are schematic diagrams of the pin moving mechanism 4 as viewed from the base end side (rear side) of the telescopic boom 14. The operation of the cylinder connecting mechanism 45 transitioning from the extended state to the retracted state is the extraction operation of the cylinder connecting mechanism 45. The operation of the cylinder connecting mechanism 45 transitioning from the retracted state to the extended state is the engagement operation of the cylinder connecting mechanism 45.

[0057] When the cylinder connecting mechanism 45 is in the expanded state, the cylinder connecting pins 454A, 454B are engaged with the cylinder pin receiving portions 1411, 1412 of the boom (for example, the distal boom portion 141). In this engaged state, the boom and the cylinder member 32 (see FIGS. 2A to 2E) are connected.

[0058] Furthermore, when the cylinder connecting mechanism 45 is in the contracted state, the cylinder connecting pins 454A, 454B are disengaged from the cylinder pin receiving portions 1411, 1412. In this disengaged state, the boom and the cylinder member 32 are disengaged.

[0059] Specifically, the cylinder connecting mechanism 45 includes a first rack bar 451 , a first gear mechanism 452 , a second gear mechanism 453 , cylinder connecting pins 454 A and 454 B, and a first biasing mechanism 455 .

[0060] The first rack bar 451 moves in its axial direction in response to power (specifically, rotation) transmitted from the switching mechanism 47 (specifically, switch gear 471). The first rack bar 451 is located at a first position when the cylinder coupling mechanism 45 is in the expanded state (see FIG. 3A).

[0061] On the other hand, the first rack bar 451 is located at the second position when the cylinder coupling mechanism 45 is in the contracted state (see FIG. 3C). That is, the first rack bar 451 moves between the first position and the second position.

[0062] In the expanded state, when the switch gear 471 rotates in the first rotation direction A1, the first rack tooth portion of the first rack bar 451 meshes with the tooth portion of the switch gear 471. When the switch gear 471 further rotates in the first rotation direction A1 from this state, the first rack bar 451 moves in accordance with the rotation of the switch gear 471.

[0063] The first rack bar 451 has a second rack tooth portion and a third rack tooth portion. The second rack tooth portion meshes with a first gear mechanism 452 (described later). The third rack tooth portion meshes with a second gear mechanism 453 (described later).

[0064] The first gear mechanism 452 rotates in response to the movement of the first rack bar 451. The first gear mechanism 452 also meshes with a cylinder connecting pin 454A, which will be described later.

[0065] The second gear mechanism 453 rotates in response to the movement of the first rack bar 451. In addition, the second gear mechanism 453 is in mesh with a cylinder connecting pin 454B, which will be described later.

[0066] The cylinder connecting pins 454A, 454B are arranged on the same straight line. Such cylinder connecting pins 454A, 454B are supported by a trunnion (not shown). The cylinder connecting pins 454A, 454B move in their axial directions in response to the rotation of the first gear mechanism 452 and the second gear mechanism 453.

[0067] When the electric motor 41 is de-energized and the brake mechanism 42 is turned OFF while the cylinder connecting mechanism 45 is in the contracted state (see FIG. 3C), the first biasing mechanism 455 returns the cylinder connecting mechanism 45 to the expanded state.

[0068] In other words, when the cylinder connecting mechanism 45 is in a contracted state, the first biasing mechanism 455 returns the cylinder connecting pins 454A, 454B to the reference position (in other words, the engaged state) when the electric motor 41 is in a non-energized state (stopped state) and the brake mechanism 42 is in an OFF state.

[0069] Specifically, the first biasing mechanism 455 has a pair of coil springs 455a, 455b (see FIG. 3A). The coil spring 455a is provided between a trunnion (not shown) and the cylinder connecting pin 454A.

[0070] The coil spring 455a constantly biases the cylinder connecting pin 454A. The direction in which the coil spring 455a biases the cylinder connecting pin 454A coincides with the direction from the base end portion to the tip end portion of the cylinder connecting pin 454A.

[0071] The coil spring 455b is provided between the trunnion (not shown) and the cylinder connecting pin 454B. The coil spring 455b constantly biases the cylinder connecting pin 454B. The direction in which the coil spring 455b biases the cylinder connecting pin 454B coincides with the direction from the base end to the tip end of the cylinder connecting pin 454B.

[0072] The configuration of the first biasing mechanism 455 as described above contributes to the miniaturization of the pin moving mechanism 4. The arrangement of the coil springs 455a and 455b is not limited to that of this embodiment. The operation of the cylinder connecting mechanism 45 will be described later.

[0073] The boom connection mechanism 46 is an example of a second connection mechanism, which connects adjacent booms to each other and releases the connection using a motor. Specifically, the boom connection mechanism 46 transitions between an extended state (see FIG. 4A) and a retracted state (see FIG. 4C) based on the rotation of the electric motor 41 under the control of the control unit 50.

[0074] The operation of the boom connection mechanism 46 transitioning from the extended state to the retracted state is the retraction operation of the boom connection mechanism 46. The operation of the boom connection mechanism 46 transitioning from the retracted state to the extended state is the retraction operation of the boom connection mechanism 46.

[0075] In the extended state, the boom connection mechanism 46 can be in either an engaged state or a disengaged state with respect to a boom connection pin (for example, a pair of boom connection pins 144a). When the boom connection mechanism 46 is engaged with the boom connection pin, it transitions from the extended state to the retracted state, thereby disengaging the boom connection pin from the boom.

[0076] Furthermore, the boom connecting mechanism 46, while engaged with the boom connecting pin, transitions from a contracted state to an extended state, thereby engaging the boom connecting pin with the boom.

[0077] As shown in FIGS. 4A to 4C, the boom connecting mechanism 46 includes a pair of second rack bars 461a and 461b, a synchronization gear 462, and a second biasing mechanism 463.

[0078] The pair of second rack bars 461a, 461b are, for example, shaft members that are long in the left-right direction and are arranged in parallel and spaced apart in the front-rear direction. The pair of second rack bars 461a, 461b are each arranged above the first rack bar 451 of the cylinder linking mechanism 45.

[0079] The pair of second rack bars 461a, 461b each have a synchronizing rack tooth portion on an opposing surface. Each of the synchronizing rack tooth portions is meshed with a synchronizing gear 462. When the synchronizing gear 462 rotates, the one second rack bar 461a and the other second rack bar 461b move in opposite directions in the axial direction of the second rack bars 461a, 461b.

[0080] The pair of second rack bars 461a, 461b each have a locking claw portion at the tip thereof, which engages with the boom connecting pins (for example, boom connecting pins 144a, 144b) when the boom connecting pins are moved.

[0081] One of the second rack bars 461a moves in its axial direction in response to power (specifically, rotation) transmitted from the switching mechanism 47 (specifically, switch gear 471). One of the second rack bars 461a is located at a first position when the boom connection mechanism 46 is in an extended state. On the other hand, one of the second rack bars 461a is located at a second position when the boom connection mechanism 46 is in a retracted state. In other words, one of the second rack bars 461a moves between the first position and the second position.

[0082] When the switch gear 471 of the switching mechanism 47 rotates in the second rotation direction A2 from the extended state of the boom connection mechanism 46, the rack teeth portion of one of the second rack bars 461a meshes with the teeth portion of the switch gear 471. When the switch gear 471 further rotates in the second rotation direction A2 from this state, one of the second rack bars 461a moves in its axial direction in response to the rotation of the switch gear 471.

[0083] Furthermore, when one second rack bar 461a moves, the synchronization gear 462 rotates, and the other second rack bar 461b moves in its axial direction. The movement direction of one second rack bar 461a is opposite to the movement direction of the other second rack bar 461b.

[0084] When the electric motor 41 is de-energized and the brake mechanism 42 is turned off while the boom connection mechanism 46 is in the contracted state, the second biasing mechanism 463 returns the boom connection mechanism 46 to the extended state. The second biasing mechanism 463 biases the pair of second rack bars 461a, 461b in directions away from each other.

[0085] In other words, when the boom connecting mechanism 46 is in a contracted state, the second biasing mechanism 463 returns the boom connecting pin 144a to the reference position (in other words, the engaged state) when the electric motor 41 is in a non-energized state (stopped state) and the brake mechanism 42 is in an OFF state.

[0086] Specifically, the second biasing mechanism 463 is composed of a pair of coil springs 463a, 463b. The pair of coil springs 463a, 463b bias the base ends of the pair of second rack bars 461a, 461b toward the tip ends, respectively.

[0087] The position information detection device 48 is a non-contact potentiometer. The position information detection device 48 has a detection object (not shown) and a sensor (not shown). The detection object is a magnet, and is fixed to the transmission shaft 432. The detection object rotates together with the transmission shaft 432.

[0088] The object to be detected may be provided on a member that rotates together with the output shaft of the electric motor 41. Therefore, the object to be detected rotates together with the output shaft of the electric motor 41.

[0089] The sensor has a Hall element and is provided facing the object to be detected in a predetermined direction. For example, the sensor may be fixed to a trunnion (not shown) via a support.

[0090] The sensor outputs a voltage corresponding to the phase of the object to be detected. That is, the sensor outputs a voltage corresponding to the rotation angle of the transmission shaft 432 to which the object to be detected is fixed (that is, the rotation angle of the electric motor 41).

[0091] The position information detecting device 48 detects information relating to the positions (in other words, the states) of the cylinder connecting pins 454A, 454B in accordance with the detection values ​​of the sensors. The position information detecting device 48 also detects information relating to the position of the boom connecting pin 144a in accordance with the detection values ​​of the sensors.

[0092] The information regarding the positions (in other words, the states) of the cylinder connecting pins 454A, 454B and the information regarding the position of the boom connecting pin 144a is the rotation angle of the electric motor 41 from the reference position (specifically, the rotation angle of the transmission shaft 432).

[0093] (Operation: Cylinder linkage mechanism) An example of the operation of the cylinder connecting mechanism 45 and the boom connecting mechanism 46 will now be described.

[0094] 2A to 2E and 3A to 3C, an example of the operation of the cylinder coupling mechanism 45 will be described. The operation of the cylinder coupling mechanism 45 is controlled by the control unit 50. The operation of the cylinder coupling mechanism 45 is the operation when the cylinder coupling mechanism 45 transitions from the expanded state to the contracted state based on the power of the electric motor 41, and the operation when the cylinder coupling mechanism 45 transitions from the contracted state to the expanded state based on the biasing force of the first biasing mechanism 455.

[0095] When the cylinder coupling mechanism 45 transitions from the extended state to the contracted state, the pair of cylinder coupling pins 454A, 454B enters the withdrawn state. The control by the control unit 50 to transition the cylinder coupling mechanism 45 from the extended state to the contracted state is referred to as the withdrawn operation control of the cylinder coupling mechanism.

[0096] Fig. 3A is a schematic diagram showing the expanded state of the cylinder coupling mechanism 45 and the engagement state between the pair of cylinder coupling pins 454A, 454B and the pair of cylinder pin receivers 1411, 1412 of the tip boom 141. Fig. 3B is a schematic diagram showing the state of the cylinder coupling mechanism 45 in the middle of transitioning from the expanded state to the contracted state.

[0097] 3C is a schematic diagram showing a state in which the cylinder connecting mechanism 45 is contracted and the pair of cylinder connecting pins 454A, 454B and the pair of cylinder pin receiving portions 1411, 1412 of the tip boom 141 are separated from each other.

[0098] The expanded state of the cylinder coupling mechanism 45 shown in Fig. 3A corresponds to the state of the cylinder coupling mechanism 45 in Fig. 2A to Fig. 2D. The state of the cylinder coupling mechanism 45 shown in Fig. 3B corresponds to a state in which the cylinder coupling mechanism 45 is in transition from the state shown in Fig. 2D to the state shown in Fig. 2E. The contracted state of the cylinder coupling mechanism 45 shown in Fig. 3C corresponds to the state of the cylinder coupling mechanism 45 shown in Fig. 2E.

[0099] When the cylinder linking mechanism 45 transitions from the extended state to the retracted state, the control unit 50 (see FIGS. 3A to 3C) drives the electric motor 41. The power of the electric motor 41 is transmitted to a pair of cylinder linking pins 454A, 454B via the first and second transmission paths described below. The control unit 50 may actually be configured such that a CPU, ROM, RAM, and HDD are connected via a bus, or may be configured such that it is composed of a one-chip LSI.

[0100] The first transmission path is a path through which the power of the electric motor 41 is transmitted in the following order. (First transmission path) Switch gear 471 → First rack bar 451 → First gear mechanism 452 → Right cylinder connecting pin 454A

[0101] The second transmission path is a path through which the power of the electric motor 41 is transmitted in the following order. (Second transmission path) Switch gear 471 → First rack bar 451 → Second gear mechanism 453 → Left cylinder connecting pin 454B

[0102] Specifically, first, in the first transmission path and the second transmission path, the switch gear 471 rotates in a first rotation direction (the direction indicated by the arrow A1 in FIG. 3A) based on the power of the electric motor 41.

[0103] In the first transmission path, when the switch gear 471 rotates in the first direction, the first rack bar 451 moves to the right in response to the rotation. In the description of the operation of the cylinder coupling mechanism 45, the right side and the left side refer to the right side and the left side in Figures 3A to 3C.

[0104] In the first transmission path, when the first rack bar 451 moves to the right, the right cylinder connecting pin 454A moves to the left via the first gear mechanism 452. On the other hand, in the second transmission path, when the first rack bar 451 moves to the right, the left cylinder connecting pin 454B moves to the right via the second gear mechanism 453.

[0105] The position information detection device 48 detects the positions of the pair of cylinder connecting pins 454A, 454B. The position information detection device 48 sends the detected value to the control unit 50. The control unit 50 controls the brake mechanism 42 and the electric motor 41 based on the detected value obtained from the position information detection device 48.

[0106] In this embodiment, when the detection value of the position information detection device 48 satisfies a predetermined condition, the control unit 50 supplies power to the brake mechanism 42 to turn on the brake mechanism 42. In the on state, the brake mechanism 42 applies a braking force to the electric motor 41.

[0107] As a result, the operation of the cylinder linking mechanism 45 is restricted. In other words, the cylinder linking mechanism 45 is maintained in the contracted state. That is, the positions of the pair of cylinder linking pins 454A, 454B are maintained. Thereafter, the control unit 50 stops the electric motor 41.

[0108] Next, the operation of the cylinder coupling mechanism 45 when it transitions from the contracted state to the expanded state based on the biasing force of the first biasing mechanism 455 will be described.

[0109] When the cylinder coupling mechanism 45 transitions from the contracted state to the expanded state, the pair of cylinder coupling pins 454A, 454B enters the engaged state. The control by the control unit 50 to transition the cylinder coupling mechanism 45 from the contracted state to the expanded state is referred to as the cylinder coupling mechanism engaging operation control. Note that the state of the pair of cylinder coupling pins 454A, 454B shown in Figures 2A and 3A is the engaged state of the pair of cylinder coupling pins 454A, 454B.

[0110] In controlling the closing operation of the cylinder linking mechanism, the control unit 50 turns the brake mechanism 42 to the OFF state when the cylinder linking mechanism 45 is in the contracted state. In the OFF state, the brake mechanism 42 does not apply a braking force to the electric motor 41.

[0111] As a result, the cylinder coupling mechanism 45 is able to transition from the contracted state to the expanded state based on the biasing force of the first biasing mechanism 455. The operation of the cylinder coupling mechanism 45 when transitioning from the contracted state to the expanded state is the reverse of the operation of the cylinder coupling mechanism 45 when transitioning from the expanded state to the contracted state.

[0112] That is, the cylinder coupling mechanism 45 transitions from the contracted state shown in Fig. 3C, through the state shown in Fig. 3B, to the expanded state shown in Fig. 3A. As a result, the pair of cylinder coupling pins 454A, 454B enter the engaged state shown in Fig. 3A.

[0113] (Movement: Boom connection mechanism) Next, an example of the operation of the boom linkage mechanism 46 will be described with reference to FIGS. 2A to 2E and 4A to 4C.

[0114] The operation of the boom connection mechanism 46 is controlled by the control unit 50. The operation of the boom connection mechanism 46 includes the operation when the boom connection mechanism 46 transitions from the extended state to the retracted state based on the power of the electric motor 41, and the operation when the boom connection mechanism 46 transitions from the retracted state to the extended state based on the biasing force of the first biasing mechanism 455.

[0115] When the boom connection mechanism 46 transitions from the extended state to the retracted state while engaged with the pair of boom connection pins 144a, the pair of boom connection pins 144a enters the extracted state. The control by the control unit 50 to transition the boom connection mechanism 46 from the extended state to the retracted state is referred to as extracting operation control of the boom connection mechanism.

[0116] Fig. 4A is a schematic diagram showing the boom connection mechanism 46 in an extended state, and an engaged state between the pair of boom connection pins 144a and the pair of first boom pin receivers 142b of the intermediate boom 142. Fig. 4B is a schematic diagram showing the boom connection mechanism 46 in the middle of transitioning from the extended state to the retracted state. Furthermore, Fig. 4C is a schematic diagram showing the boom connection mechanism 46 in a retracted state, and a disengaged state between the pair of boom connection pins 144a and the pair of first boom pin receivers 142b of the intermediate boom 142.

[0117] The extended state of the boom connection mechanism 46 shown in Fig. 4A corresponds to the state of the boom connection mechanism 46 in Fig. 2A. The state of the boom connection mechanism 46 shown in Fig. 4B corresponds to a state in which the boom connection mechanism 46 is in transition from the state shown in Fig. 2A to the state shown in Fig. 2B. The retracted state of the boom connection mechanism 46 shown in Fig. 4C corresponds to the state of the boom connection mechanism 46 shown in Fig. 2B.

[0118] The boom linkage mechanism 46 transitions between an extended state and a retracted state based on the power of the electric motor 41. Here, the position of the switch gear 471 shown in FIG.

[0119] When the boom connection mechanism 46 transitions from the extended state to the retracted state, the control unit 50 (see FIGS. 4A to 4C) drives the electric motor 41 in the direction opposite to the direction in which the cylinder connection mechanism 45 is operated. The power of the electric motor 41 is transmitted through the following path. (Transmission path) Switch gear 471 → one second rack bar 461a → synchronous gear 462 → other second rack bar 461b

[0120] First, in the transmission path, the switch gear 471 rotates in the second rotation direction (the direction indicated by the arrow A2 in FIG. 4A) based on the power of the electric motor 41. Then, the teeth of the switch gear 471 mesh with the rack teeth of one of the second rack bars 461a.

[0121] From this state, when the switch gear 471 further rotates in the second rotation direction A2, one of the second rack bars 461a moves to the right in Fig. 4A in accordance with the rotation of the switch gear 471. In the description of the operation of the boom connecting mechanism 46, the right side and the left side refer to the right side and the left side in Figs. 4A to 4C.

[0122] Then, in response to the movement of one second rack bar 461a to the right, the synchronization gear 462 rotates. Then, in response to the rotation of the synchronization gear 462, the other second rack bar 461b moves to the left.

[0123] When the pair of second rack bars 461a, 461b are engaged with the pair of boom connecting pins 144a and transition from the extended state to the retracted state, the pair of boom connecting pins 144a disengage from the pair of first boom pin receiving portions 142b of the intermediate boom 142 (see Figure 4C).

[0124] The position information detection device 48 is an example of a detection unit, and detects the positions of the pair of boom connecting pins 144a. The position information detection device 48 sends the detected value to the control unit 50. The control unit 50 controls the brake mechanism 42 and the electric motor 41 based on the detected value acquired from the position information detection device 48.

[0125] In this embodiment, when the detection value of the position information detection device 48 satisfies a predetermined condition, the control unit 50 supplies power to the brake mechanism 42 to turn the brake mechanism on. In the on state, the brake mechanism 42 applies a braking force to the electric motor 41.

[0126] As a result, the operation of the boom connection mechanism 46 is restricted. In other words, the boom connection mechanism 46 is maintained in the contracted state. That is, the positions of the pair of boom connection pins 144a are maintained. Thereafter, the control unit 50 stops the electric motor 41.

[0127] Next, the operation of the boom connection mechanism 46 when it transitions from the contracted state to the extended state based on the biasing force of the second biasing mechanism 463 will be described.

[0128] When the boom connection mechanism 46 transitions from the retracted state to the extended state while engaged with the pair of boom connection pins 144a, the pair of boom connection pins 144a enter the retracted state. The control by the control unit 50 to transition the boom connection mechanism 46 from the retracted state to the extended state is referred to as the retracting operation control of the boom connection mechanism. Note that the state of the pair of boom connection pins 144a shown in Figures 2A and 4A is the retracted state of the pair of boom connection pins 144a.

[0129] In controlling the closing operation of the boom connection mechanism, the control unit 50 turns the brake mechanism 42 to the OFF state when the boom connection mechanism 46 is in the contracted state. In the OFF state, the brake mechanism 42 does not apply a braking force to the electric motor 41.

[0130] As a result, the boom connection mechanism 46 is able to transition from the retracted state to the extended state based on the biasing force of the second biasing mechanism 463. The operation of the boom connection mechanism 46 when transitioning from the retracted state to the extended state is the reverse of the operation of the boom connection mechanism 46 when transitioning from the extended state to the retracted state described above.

[0131] That is, the boom connection mechanism 46 transitions from the contracted state shown in Fig. 4C, through the state shown in Fig. 4B, to the extended state shown in Fig. 4A. As a result, the pair of boom connection pins 144a enter the engaged state shown in Fig. 4A.

[0132] The inspection control will be described below with reference to Fig. 5 to Fig. 8. The mobile crane 1 according to this embodiment performs inspection control at appropriate timing during the extension and retraction operation of the telescopic boom 14. The inspection control is control carried out by the control unit 50.

[0133] The inspection control includes motor inspection control, brake inspection control, and on-going operation inspection control. Figure 5 is a flowchart of the inspection control. Figure 6 is a flowchart of the motor inspection control in the inspection control. Figure 7 is a flowchart of the brake inspection control in the inspection control. Figure 8 is a flowchart of the on-going operation inspection control in the inspection control.

[0134] First, an overview of the inspection control will be described with reference to Fig. 5. The inspection control is performed by the control unit 50. Below, an example will be described in which the control unit 50 performs the inspection control when the telescopic boom 14 is in the fully retracted state (the state shown in Fig. 2A). However, the timing when the control unit 50 performs the inspection control is not limited to when the telescopic boom 14 is in the fully retracted state. This point will be described later.

[0135] (Step S1) First, in step S1 of Fig. 5, the control unit 50 performs motor inspection control. In step S1 of Fig. 5, the telescopic boom 14 is in a fully retracted state (the state shown in Fig. 2A). Specific processing of the motor inspection control is shown in Fig. 6. The motor inspection control will be described later.

[0136] (Step S2) Next, in step S2 of FIG. 5, the control unit 50 determines whether the state of the electric motor 41 is normal or not based on the result of the motor inspection control.

[0137] If the state of the electric motor 41 is normal in step S2 ("YES" in step S2), the control unit 50 advances the control process to step S3.

[0138] Furthermore, if the state of the electric motor 41 is not normal in step S2 ("NO" in step S2), the control unit 50 advances the control process to step S4.

[0139] (Step S3) Next, in step S3 of Fig. 5, the control unit 50 performs brake inspection control. Specific processing of the brake inspection control is shown in Fig. 7. The brake inspection control will be described later. After the brake inspection control is completed, the control unit 50 advances the control processing to step S5.

[0140] (Step S4) Next, in step S4 of Fig. 5, the control unit 50 determines whether the motor inspection control has been completed a predetermined number of times. In this embodiment, the predetermined number of times is three.

[0141] If the motor inspection control has been completed the predetermined number of times in step S4 ("YES" in step S4), the control unit 50 advances the control process to step S41.

[0142] In step S41, the control unit 50 notifies information indicating that the state of the electric motor 41 is abnormal (hereinafter referred to as motor abnormality information). The motor abnormality information corresponds to an example of a second alarm. The control unit 50 may, for example, display the motor abnormality information on a display unit (not shown) provided on the mobile crane 1. Note that the method of notifying the motor abnormality information is not limited to display.

[0143] In this way, when the operation of the electric motor 41 falls into the warning state three times in a row, the control unit 50 issues a second alarm (i.e., motor abnormality information) and stops the operation of the boom linkage mechanism 46. Note that this warning state means a state in which it is determined in step S2 that the state of the electric motor 41 is not normal.

[0144] Furthermore, if the motor inspection control has not been completed the predetermined number of times in step S4 ("NO" in step S4), the control unit 50 advances the control process to step S1. Thereafter, the control unit 50 performs the process of step S1.

[0145] Note that before transitioning from step S4 to step S1, the control unit 50 may issue information indicating that the state of the electric motor 41 is not normal (hereinafter referred to as motor warning information). The control unit 50 may, for example, display the motor warning information on a display unit (not shown) provided on the mobile crane 1. The motor warning information corresponds to an example of a first alarm.

[0146] In this way, when the operation of the electric motor 41 falls into a warning state once or twice consecutively during the motor inspection control, the control unit 50 issues motor warning information and repeats the motor inspection control. Note that this warning state means a state in which the condition of the electric motor 41 is determined to be abnormal in step S2.

[0147] (Step S5) Next, in step S5 of FIG. 5, the control unit 50 determines whether or not the brake mechanism 42 is in a normal state based on the result of the brake inspection control.

[0148] If the state of the brake mechanism 42 is normal in step S5 ("YES" in step S5), the control unit 50 advances the control process to step S6.

[0149] Furthermore, if the state of the brake mechanism 42 is not normal in step S5 ("NO" in step S5), the control unit 50 advances the control process to step S7.

[0150] (Step S6) Next, in step S6 of Fig. 5, the control unit 50 determines whether the extension method is the self-extension method. The self-extension method refers to an extension method in which the tip boom 141 is extended when the telescopic boom 14 is in the fully retracted state (the state shown in Fig. 2A).

[0151] On the other hand, when the telescopic boom 14 is in the fully retracted state (the state shown in FIG. 2A), an extension method in which a boom other than the tip boom 141 (for example, the middle boom 142) is extended is referred to as a multi-stage extension method. The extension method in this example is a self-stage extension method.

[0152] If the extension method is the self-stage extension method in step S6 ("YES" in step S6), the control unit 50 ends the control process. That is, the inspection control ends. In this way, if the extension method is the self-stage extension method, the control unit 50 performs motor inspection control and brake inspection control in the inspection control.

[0153] Furthermore, if the decompression method is not the self-decompression method in step S6 ("NO" in step S6), the control unit 50 advances the control process to step S8.

[0154] (Step S7) Next, in step S7 of Fig. 5, the control unit 50 determines whether the brake inspection control has been completed a predetermined number of times. In this embodiment, the predetermined number of times is three.

[0155] If the brake inspection control has been performed the predetermined number of times in step S7 ("YES" in step S7), the control unit 50 advances the control process to step S71.

[0156] In step S71, the control unit 50 notifies information indicating that the state of the brake mechanism 42 is abnormal (hereinafter referred to as brake abnormality information). The brake abnormality information corresponds to an example of a second alarm. The control unit 50 may, for example, display the brake abnormality information on a display unit (not shown) provided on the mobile crane 1. Note that the method of notifying the brake abnormality information is not limited to display.

[0157] In this way, when the operation of the brake mechanism 42 falls into the warning state three times in a row, the control unit 50 issues a second alarm (i.e., brake abnormality information) and stops the operation of the boom linkage mechanism 46. Note that this warning state means a state in which it is determined in step S5 that the state of the brake mechanism 42 is not normal.

[0158] Furthermore, in step S7, if the brake inspection control has not been completed the predetermined number of times ("NO" in step S7), the control unit 50 advances the control process to step S1. Thereafter, the control unit 50 performs the process of step S1. Thus, in this example, if the result of the brake inspection control indicates an abnormality in the brake mechanism and the brake inspection control has not been performed the predetermined number of times, the control unit 50 returns the control process to step S1.

[0159] Before proceeding from step S7 to step S1, the control unit 50 may issue information indicating that the state of the brake mechanism 42 is not normal (hereinafter referred to as brake warning information). The brake warning information corresponds to an example of a first alarm. The control unit 50 may, for example, display the brake warning information on a display unit (not shown) provided on the mobile crane 1.

[0160] In this way, when the operation of the electric motor 41 falls into a warning state once or twice consecutively during the brake inspection control, the control unit 50 issues brake warning information and repeats the brake inspection control. Note that this warning state means a state in which it is determined in step S5 that the state of the brake mechanism 42 is not normal.

[0161] (Step S8) Next, in step S8 of Fig. 5, the control unit 50 performs the entering operation check control. The entering operation checked in step S8 is the operation of the boom connection mechanism 46 transitioning the pair of boom connection pins 144a from the extracted state to the entering state.

[0162] In other words, the entering operation inspected in step S8 is the operation of transitioning the boom linkage 46 from the contracted state to the extended state. Specific processing of the entering operation inspection control is shown in Fig. 8. The entering operation inspection control will be described later.

[0163] After the end of the turning-on operation check control, the control unit 50 advances the control process to step S9. Such turning-on operation check control is performed only when the extension method is the multi-stage extension method.

[0164] (Step S9) Next, in step S9 of FIG. 5, the control unit 50 determines, as a result of the closing operation check control, whether or not the closing operation of the boom linkage mechanism 46 has been performed normally.

[0165] If the closing operation of the boom linkage mechanism 46 has been performed normally in step S9 ("YES" in step S9), the control unit 50 ends the control process. That is, the control unit 50 ends the inspection control.

[0166] Furthermore, in step S9, if the closing operation of the boom linkage mechanism 46 is not performed normally ("NO" in step S5), the control unit 50 advances the control process to step S91.

[0167] In step S91, the control unit 50 notifies information indicating that there is an abnormality in the retracting operation of the boom connection mechanism 46 (hereinafter referred to as retracting operation abnormality information). The control unit 50 may, for example, display the retracting operation abnormality information on a display unit (not shown) provided on the mobile crane 1. Note that the method of notifying the retracting operation abnormality information is not limited to display.

[0168] (Motor inspection control) Next, the motor inspection control performed in step S1 of Fig. 5 will be described with reference to Fig. 6. The motor inspection control is a control for inspecting whether the state of the electric motor 41 is normal. The motor inspection control is performed when the telescopic boom 14 is in the fully retracted state (the state shown in Fig. 2A). In the motor inspection control, the control unit 50 transitions the boom linkage mechanism 46 from the extended state to the retracted state.

[0169] At this time, the boom connection mechanism 46 is engaged with the pair of boom connection pins 144a (see FIG. 4A). When the boom connection mechanism 46 transitions from the extended state to the retracted state, the pair of boom connection pins 144a are removed from the first boom pin receivers 142b and enter a removed state. The control unit 50 determines whether the electric motor 41 is normal by measuring the time it takes for the pair of boom connection pins 144a to be removed from the first boom pin receivers 142b.

[0170] That is, in the motor inspection control, the control unit 50 inspects the operation of the electric motor 41 based on the release operation of the boom connection mechanism 46 when the connection between adjacent booms is released.

[0171] (Step S101) Specifically, in step S101 in Fig. 6, the control unit 50 drives the electric motor 41. That is, the control unit 50 sets the state of the electric motor 41 to the ON state. The electric motor 41 rotates in a direction that rotates the switch gear 471 in the second rotation direction (the direction indicated by arrow A2 in Fig. 4A). As a result, the boom linkage mechanism 46 is actuated.

[0172] (Step S102) Next, in step S102 of Fig. 6, the control unit 50 starts measurement. The control unit 50 measures the time it takes for the boom linkage mechanism 46 to transition from the extended state (the state shown in Fig. 4A) to the retracted state (the state shown in Fig. 4C). Then, the control unit 50 advances the control process to step S103.

[0173] (Step S103) 6, the control unit 50 determines whether the pair of boom connecting pins 144a have come out of the pair of first boom pin receivers 142b. In other words, the control unit 50 determines whether the pair of boom connecting pins 144a have come out of the pair of first boom pin receivers 142b.

[0174] The control unit 50 determines, based on the detection value of the position information detection device 48, whether or not the state of the pair of boom connecting pins 144a has become the removed state.

[0175] In step S103, if the state of the pair of boom connecting pins 144a is the uncoupled state ("YES" in step S103), the control unit 50 ends the measurement and ends the motor inspection control. In this case, the state of the electric motor 41 is normal.

[0176] In addition, the control unit 50 repeats the processing of step S103 to step S106 described later in the motor inspection control. Therefore, in the motor inspection control, the control unit 50 determines that the electric motor 41 is normal if the time required to release the connection between adjacent booms is within a second predetermined time described later.

[0177] Furthermore, in step S103, if the state of the pair of boom connecting pins 144a is not the removed state ("NO" in step S103), the control unit 50 advances the control processing to step S104.

[0178] (Step S104) Next, in step S104 of Fig. 6, the control unit 50 determines whether or not a first predetermined time has elapsed since the start of measurement in step S102. The first predetermined time is, for example, 2 seconds.

[0179] If the control unit 50 determines in step S104 that the first predetermined time has elapsed ("YES" in step S104), the control process proceeds to step S105.

[0180] Furthermore, if the control unit 50 determines in step S104 that the first predetermined time has not elapsed ("NO" in step S104), the control unit 50 advances the control process to step S103. Then, the control unit 50 performs the process of step S103.

[0181] (Step S105) Next, in step S105 of FIG. 6, the control unit 50 notifies information indicating that a first predetermined time has elapsed since the measurement was started in step S102 (hereinafter referred to as first predetermined time elapsed information).

[0182] The control unit 50 may, for example, display the first predetermined time elapsed information on a display unit (not shown) provided on the mobile crane 1. Note that the method of notifying the first predetermined time elapsed information is not limited to display. The control unit 50 then proceeds to step S106.

[0183] (Step S106) Next, in step S106 of Fig. 6, the control unit 50 determines whether or not a second predetermined time has elapsed since the start of measurement in step S102. The second predetermined time is, for example, 5 seconds.

[0184] If the control unit 50 determines in step S106 that the second predetermined time has elapsed ("YES" in step S106), the control unit 50 advances the control process to step S107.

[0185] Furthermore, if the control unit 50 determines in step S106 that the second predetermined time has not elapsed ("NO" in step S106), the control unit 50 advances the control process to step S103. Then, the control unit 50 performs the process of step S103.

[0186] (Step S107) Next, in step S107 of Fig. 6, the control unit 50 stops the electric motor 41. Then, the control unit 50 advances the control process to step S108.

[0187] (Step S108) Next, in step S108 of Fig. 6, the control unit 50 counts up the information indicating the number of times the motor inspection control has been performed by 1. Then, the control unit 50 ends the measurement and ends the motor inspection control. In this case, the state of the electric motor 41 is abnormal.

[0188] (Brake inspection control) Next, the brake inspection control performed in step S3 of Fig. 5 will be described with reference to Fig. 7. The brake inspection control is performed after the motor inspection control when the telescopic boom 14 is in the fully retracted state (the state shown in Fig. 2A).

[0189] The brake inspection control is performed when the boom connection mechanism 46 has transitioned from the extended state to the retracted state during the motor inspection control. In other words, the brake inspection control is performed when the pair of boom connection pins 144a are in the uncoupled state during the motor inspection control. In this state, the connection between adjacent booms (specifically, the tip boom 141 and the intermediate boom 142) is released.

[0190] If the brake mechanism 42 is normal, when the brake mechanism 42 is turned on while the boom connection mechanism 46 is in the retracted state, the retracted state of the boom connection mechanism 46 is maintained. In other words, the brake mechanism 42 maintains the state in which the adjacent booms (specifically, the tip boom 141 and the intermediate boom 142) are disconnected from each other.

[0191] In this way, during brake inspection control, the control unit 50 inspects the operation of the brake mechanism 42 by operating the brake mechanism 42 while the connection between adjacent booms (specifically, the tip boom 141 and the intermediate boom 142) is released.

[0192] (Step S201) 7, the control unit 50 supplies power to the brake mechanism 42 to turn the brake mechanism 42 on. In the on state, the brake mechanism 42 applies a braking force to the electric motor 41. If the brake mechanism 42 is normal, the state of the boom linkage mechanism 46 is maintained in the retracted state.

[0193] In other words, if the brake mechanism 42 is normal, the pair of boom connecting pins 144a are maintained in the uncoupled state. Then, the control unit 50 advances the control process to step S202.

[0194] (Step S202) Next, in step S202 of Fig. 7, the control unit 50 stops the electric motor 41. Then, the control unit 50 advances the control process to step S203.

[0195] (Step S203) 7, the control unit 50 starts measuring the time that has elapsed since the electric motor 41 was turned off. Then, the control unit 50 advances the control process to step S204.

[0196] (Step S204) 7, the control unit 50 determines whether the pair of boom connecting pins 144a can be maintained in the uncoupling state for a third predetermined time. In other words, the control unit 50 determines whether the boom connecting mechanism 46 can be maintained in the retracted state for a third predetermined time. The third predetermined time is, for example, one second.

[0197] The control unit 50 determines, based on the detection value of the position information detection device 48, whether or not the state of the pair of boom connecting pins 144a can be maintained in the uncoupled state.

[0198] If the state of the pair of boom connecting pins 144a is maintained in the uncoupled state for the third predetermined time in step S204 ("YES" in step S204), the control unit 50 proceeds to step S205.

[0199] Furthermore, in step S204, if the state of the pair of boom connecting pins 144a is not maintained in the uncoupled state for the third predetermined time period ("NO" in step S204), the control unit 50 advances the control process to step S206.

[0200] (Step S205) Next, in step S205 of Fig. 7, the control unit 50 ends the measurement. Then, the control unit 50 ends the brake inspection control. In this case, the state of the brake mechanism 42 is normal. In this way, the control unit 50 determines that the brake mechanism is normal when the brake mechanism 42 maintains the state in which the connection between adjacent booms (specifically, the tip boom 141 and the intermediate boom 142) is released for the third predetermined time or longer.

[0201] (Step S206) 7, the control unit 50 stops the supply of power to the brake mechanism 42 to turn off the brake mechanism 42. Then, the control unit 50 advances the control process to step S207.

[0202] (Step S207) 7, the control unit 50 counts up the information indicating the number of times the brake inspection control has been performed by 1. Then, the control unit 50 ends the measurement and ends the brake inspection control. In this case, the state of the brake mechanism 42 is abnormal.

[0203] (Input operation check control) Next, the entering operation inspection control performed in step S8 of Fig. 5 will be described with reference to Fig. 8. The entering operation inspection control is performed after the brake inspection control when the telescopic boom 14 is in the fully retracted state (the state shown in Fig. 2A). In addition, the entering operation inspection control is performed only when the extension method is the multi-stage extension method.

[0204] The retracting operation check control is control that determines whether the operation of the boom connection mechanism 46 is normal when it transitions from the retracted state to the extended state. In other words, the retracting operation check control is control that determines whether the operation of the boom connection mechanism 46 is normal when the pair of boom connecting pins 144a transitions from the extracted state to the retracted state.

[0205] In the control of the entrance operation inspection, the control unit 50 operates the boom connection mechanism 46 to connect adjacent booms (specifically, the tip boom 141 and the intermediate boom 142), thereby inspecting the entrance operation of the boom connection mechanism 46.

[0206] The turning-on operation check control is performed only when the electric motor 41 and the brake mechanism 42 are in a normal state.

[0207] (Step S301) 8, the control unit 50 stops the supply of power to the brake mechanism 42 to turn off the brake mechanism 42. When the brake mechanism 42 turns off, the boom connection mechanism 46 transitions from the contracted state to the extended state based on the biasing force of the second biasing mechanism 463.

[0208] If the second biasing mechanism 463 is normal, the pair of boom connecting pins 144a transitions from the withdrawn state to the engaged state.

[0209] (Step S302) Next, in step S302 of Fig. 8, the control unit 50 starts measurement. The control unit 50 measures the time that has elapsed since the brake mechanism 42 was turned off. In other words, the control unit 50 measures the time it takes for the boom connection mechanism 46 to transition from the contracted state to the extended state based on the biasing force of the second biasing mechanism 463.

[0210] In other words, the control unit 50 measures the time it takes for the pair of boom connecting pins 144a to transition from the unloaded state to the loaded state.

[0211] (Step S303) 8, the control unit 50 determines whether the pair of boom connecting pins 144a have entered the pair of first boom pin receiving portions 142b. In other words, the control unit 50 determines whether the pair of boom connecting pins 144a have entered the entered state.

[0212] The control unit 50 determines, based on the detection value of the position information detection device 48, whether or not the state of the pair of boom connecting pins 144a has become the engaged state.

[0213] In step S303, if the state of the pair of boom connecting pins 144a is the closing state ("YES" in step S303), the control unit 50 ends the measurement and ends the closing operation check control. In this case, the state of the closing operation is normal. In other words, the state of the second biasing mechanism 463 is normal.

[0214] In the closing operation check control, the control unit 50 repeats the processes of step S303 to step S306, which will be described later. Therefore, in the closing operation check control, the control unit 50 determines that the connecting operation of the boom connection mechanism is normal if the time required to connect adjacent booms (specifically, the tip boom 141 and the intermediate boom 142) is within a fifth predetermined time.

[0215] Furthermore, in step S303, if the state of the pair of boom connecting pins 144a is not the engaged state ("NO" in step S303), the control unit 50 advances the control processing to step S304.

[0216] (Step S304) 8, the control unit 50 determines whether a fourth predetermined time has elapsed since the start of measurement in step S302. The fourth predetermined time is, for example, 2 seconds.

[0217] If the fourth predetermined time has elapsed in step S304 ("YES" in step S304), the control unit 50 advances the control process to step S305.

[0218] On the other hand, if the fourth predetermined time has not elapsed in step S304 ("NO" in step S304), the control unit 50 advances the control process to step S303. Then, the control unit 50 performs the process of step S303.

[0219] (Step S305) Next, in step S305 of FIG. 8, the control unit 50 notifies information indicating that a fourth predetermined time has elapsed since the measurement was started in step S302 (hereinafter referred to as fourth predetermined time elapsed information).

[0220] The control unit 50 may, for example, display the fourth predetermined time elapsed information on a display unit (not shown) provided on the mobile crane 1. Note that the method of notifying the fourth predetermined time elapsed information is not limited to display. The control unit 50 then proceeds to step S306.

[0221] (Step S306) 8, the control unit 50 determines whether a fifth predetermined time has elapsed since the start of measurement in step S302. The fifth predetermined time is, for example, 5 seconds.

[0222] If the fifth predetermined time has elapsed in step S306 ("YES" in step S306), the control unit 50 ends the measurement and ends the closing operation check control. In this case, the state of the closing operation is abnormal. In other words, the state of the second biasing mechanism 463 is abnormal.

[0223] On the other hand, if the fifth predetermined time has not elapsed in step S306 ("NO" in step S306), the control unit 50 advances the control process to step S303. Then, the control unit 50 performs the process of step S303.

[0224] 5 to 8 are performed in the fully retracted state (see FIG. 2A) of the telescopic boom 14. This is because, in the fully retracted state of the telescopic boom 14, the load of the boom (e.g., the boom tip 141) is not acting on the boom connecting pin (e.g., the boom connecting pin 144a).

[0225] If the load of the boom is not acting on the boom connecting pin, there is no variation in the time it takes for the boom connecting pin to transition from the engaged state to the disengaged state when the electric motor 41 is in a normal state.

[0226] Therefore, by comparing the time required for the boom connecting pin to transition from the engaged state to the uncoupled state when the electric motor 41 is in a normal state with the time required for the boom connecting pin to transition from the engaged state to the uncoupled state when the electric motor 41 is in an abnormal state, it is easy to detect that an abnormality has occurred in the electric motor 41. The same applies to the second urging mechanism 463.

[0227] Note that the inspection control may be performed when the telescopic boom 14 is in a state other than the fully retracted state. For example, the inspection control may be performed when the telescopic boom 14 is in the state shown in Fig. 2E. In Fig. 2E, the telescopic boom 14 has the tip boom 141 in the extended state.

[0228] In the extension operation of the telescopic boom 14, the control unit 50 extends the intermediate boom 142 after the telescopic boom 14 shown in Fig. 2E. In the telescopic boom 14 shown in Fig. 2E, the intermediate boom 142 is in a fully retracted state. That is, the control unit 50 may perform inspection control when each of the multiple booms is in a fully retracted state.

[0229] Furthermore, in crane work, after work (referred to as a first work) is performed with the telescopic boom 14 in the state shown in Fig. 2E, another work (referred to as a second work) may be performed by extending the intermediate boom 142. In this case, when the extension work of the telescopic boom 14 (specifically, the intermediate boom 142) is resumed a predetermined time after the extension work of the telescopic boom 14 (specifically, the tip boom 141) was stopped, the control unit 50 may perform inspection control before extending the telescopic boom 14 (specifically, the intermediate boom 142).

[0230] (Actions and Effects of This Embodiment) The mobile crane 1 according to this embodiment as described above can detect the occurrence of an abnormality in the electric motor 41, brake mechanism 42, and second biasing mechanism 463 that constitute the pin moving mechanism 4, which is an electric coupling mechanism. The reason for this is as described above. Other functions and effects obtained from the mobile crane 1 according to this embodiment are as described above.

[0231] <Additional Notes> The technical ideas disclosed in the specification and drawings include inventions obtained by arbitrarily combining the various configurations described in the above embodiments. In particular, the technical ideas disclosed in the specification and drawings include inventions obtained by arbitrarily applying the various configurations disclosed in the specification and drawings to the above basic configuration. [Industrial Applicability]

[0232] The crane according to the present invention is not limited to a rough terrain crane, but may be any of various mobile cranes, such as an all-terrain crane, a truck crane, or a loaded truck crane (also called a cargo crane).Furthermore, the crane according to the present invention is not limited to a mobile crane, but may be any other crane equipped with a telescopic boom. [Explanation of symbols]

[0233] 1. Mobile crane 10 Running body 12 Swivel table 14 Telescopic Boom 141 Tip boom 1411, 1412 Cylinder pin receiving part 1413 Inner end surface 141b Boom pin holder 142 Intermediate Boom 142a Cylinder pin receiving part 142b First boom pin holder 142c Second boom pin holder 142d Third boom pin holder 142e Inner end surface 143 Base boom 144a, 144b, BP1, BP2, BP3, BP4 boom connecting pin 144c Tip surface 16 Wire Rope 17 Hook 2 Actuators 3 Telescopic cylinder 31 Rod member 32 Cylinder parts 4 Pin moving mechanism 41 Electric motor 42 Brake mechanism 43 Transmission Mechanism 431 Reducer 432 Transmission shaft 45 Cylinder connection mechanism 451 First Rack Bar 452 First Gear Mechanism 453 Second Gear Mechanism 454A, 454B, CP1, CP2, CP3, CP4 cylinder connecting pin 454a Tip surface 455 First biasing mechanism 455a, 455b Coil spring 46 Boom connection mechanism 461a, 461b Second rack bar 462 Synchronous Gear 463 Second biasing mechanism 463a, 463b Coil spring 47 Switching mechanism 471 Switchgear 48 Location Information Detection Device 50 control section

Claims

1. a telescopic boom having a plurality of booms and extending and retracting by a telescopic cylinder; an electric coupling mechanism including a cylinder coupling mechanism that couples the boom and the telescopic cylinder and releases the coupling between the boom and the telescopic cylinder by a motor, and a boom coupling mechanism that couples adjacent booms together and releases the coupling between the adjacent booms by the motor; a control unit that controls the operation of the electric coupling mechanism, The control unit performs inspection control to confirm the operation of the electric coupling mechanism. Work equipment.

2. In the inspection control, the control unit inspects the operation of the motor based on a release operation of the boom connection mechanism when releasing the connection between adjacent booms. The work machine according to claim 1.

3. the control unit determines that the motor is normal when a time required to release the connection between the adjacent booms is within a predetermined time. The work machine according to claim 2.

4. the electric coupling mechanism has a brake mechanism that applies a braking force to the motor, In the inspection control, the control unit inspects the operation of the brake mechanism by operating the brake mechanism in a state in which the adjacent booms are disconnected from each other. The work machine according to claim 1 .

5. the control unit determines that the brake mechanism is normal when the brake mechanism maintains the disconnected state of the adjacent booms for a predetermined time or longer. The work machine according to claim 4.

6. In the inspection control, the control unit operates the boom connection mechanism to connect adjacent booms to each other, thereby inspecting the retraction operation of the boom connection mechanism. The work machine according to claim 1 .

7. the control unit determines that the connecting operation of the boom connection mechanism is normal when the time required to connect the adjacent booms is within a predetermined time. The work machine according to claim 6.

8. The control unit performs the inspection control when the telescopic boom is in a fully retracted state. The work machine according to claim 1 .

9. The control unit performs the inspection control when each of the plurality of booms is in a fully retracted state. The work machine according to claim 1 .

10. When the extension work of the telescopic boom is to be resumed after a predetermined time has elapsed since the extension work of the telescopic boom was stopped, the control unit performs the inspection control before extending the boom. The work machine according to claim 1 .

11. In the inspection control, the control unit If the operation of the electric coupling mechanism corresponds to a warning state once or twice consecutively, a first warning is issued and the inspection control is repeated; If the operation of the electric coupling mechanism falls under the warning state three times in a row, the operation of the electric coupling mechanism is stopped while issuing a second alarm. The work machine according to claim 1 .

12. the electric coupling mechanism has a brake mechanism that applies a braking force to the motor, The control unit In the inspection control, the boom connection mechanism is operated to disconnect adjacent booms from each other, thereby inspecting the operation of the motor; After checking the operation of the motor, the brake mechanism is operated to check the operation of the brake mechanism. The work machine according to claim 1 .

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