Work equipment

Abstract

To provide a work machine capable of detecting an abnormality in a device for detecting the position of a connection pin.SOLUTION: A work machine comprises a boom extended and retracted by a telescopic cylinder, a first pin that can transition between an engaged state in which the boom and the telescopic cylinder are connected and an extracted state in which the connection is released, a second pin that can transition between an engaged state in which the adjacent booms are connected and an extracted state in which the connection is released, a main detection device and a sub-detection device for detecting a combination of states of the first pin and the second pin, and a control unit that controls the telescopic movement of the boom based on the detection result of the main detection device. The control unit controls ON / OFF of a first flag which indicates whether or not the main detection device has detected the combination during the telescoping operation of the boom, controls ON / OFF of a second flag which indicates whether or not the sub-detection device has detected the combination, and detects that an abnormality has occurred in the main detection device and the sub detection device based on the first flag and the second flag.SELECTED DRAWING: Figure 14

Description

[Technical Field]

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

[0002] A mobile crane is disclosed that includes a telescopic boom having a plurality of booms and a hydraulic actuator that extends the telescopic booms (see Patent Document 1).

[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 relative to the other booms.

[0004] The actuator includes a rod member and a cylinder member. The cylinder member is releasably connected to the movable boom by a cylinder connecting pin. When the cylinder member is displaced in the extension / retraction direction while connected to the movable boom, the movable boom moves together with the cylinder member. As a result, the telescopic boom extends and retracts.

[0005] Furthermore, in order to accurately control the telescopic boom extension and retraction of the above-mentioned crane, a technology is known in which a position detection device is provided to detect the positions of the boom connecting pin and the cylinder connecting pin. Such a crane controls the telescopic boom extension and retraction based on the detection results of the position detection device. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-96928 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the case of a crane equipped with the above-mentioned position detection device, if an abnormality occurs in the position detection device, the crane cannot perform normal extension and retraction operations. For this reason, there is a demand for technology that can detect abnormalities in the position detection device.

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

[0009] One aspect of the working machine according to the present invention is A plurality of booms that are extended and retracted by telescopic cylinders; a first pin that can transition between an engaged state in which the boom and the telescopic cylinder are connected and an uncoupled state in which the connection is released; a second pin that can transition between an on-state in which adjacent booms are connected and an off-state in which the connection is released; a main detection device and a sub detection device capable of detecting a combination of the states of the first pin and the second pin; a control unit that controls the extension and contraction operation of the boom based on the detection result of the main detection device, The control unit controls the boom during extension and retraction. controlling the ON / OFF of a first flag indicating whether the main detection device has detected a combination of the states of the first pin and the second pin, and the ON / OFF of a second flag indicating whether the sub detection device has detected a combination of the states of the first pin and the second pin; Based on the first flag and the second flag, it is detected that an abnormality has occurred in the main detector and the sub detector. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a work machine that can detect an abnormality in a device that detects the position of a connecting pin. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a mobile crane according to an embodiment. [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 3] FIG. 3 is a side view of the pin movement module. [Figure 4] FIG. 4 is a view of the pin moving module as seen from the arrow Aa in FIG. [Figure 5] FIG. 5 is a view of the pin moving module as seen from the arrow Ab in FIG. [Figure 6] FIG. 6 is a view of the detection device as seen from the arrow Aa in FIG. [Figure 7] FIG. 7 is a cross-sectional view taken along the line X1-X1 of FIG. 6 for explaining the first detection device. [Figure 8] FIG. 8 is a cross-sectional view taken along the line X2-X2 of FIG. 6 for explaining the first detection device. [Figure 9] FIG. 9 illustrates the pin moving module with the boom linkage in the extended position and the cylinder linkage in the extended position. [Figure 10A] FIG. 10A is a schematic diagram for explaining the operation of the cylinder coupling mechanism. [Figure 10B] FIG. 10B is a schematic diagram for explaining the operation of the cylinder coupling mechanism. [Figure 10C] FIG. 10C is a schematic diagram for explaining the operation of the cylinder coupling mechanism. [Figure 11A] FIG. 11A is a schematic diagram for explaining the operation of the boom connecting mechanism. [Figure 11B] FIG. 11B is a schematic diagram for explaining the operation of the boom connecting mechanism. [Figure 11C]FIG. 11C is a schematic diagram for explaining the operation of the boom connecting mechanism. [Figure 12] FIG. 12 is a timing chart for explaining the operation of the pin moving module. [Figure 13] FIG. 13 is a table for explaining the detection operation of the position information detection device. [Figure 14] FIG. 14 is a flowchart showing an example of an abnormality detection control process. [Figure 15] FIG. 15 is a diagram showing the relationship between the states of the boom connecting pin and the cylinder connecting pin and the check flag. 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, but the present invention is not limited to the embodiment described below.

[0013] [Embodiment] An overview of a mobile crane 1 according to this embodiment will be described with reference to Figs. 1 and 2A to 2E.

[0014] The mobile crane may be, for example, a rough terrain crane, an all-terrain crane, a truck crane, or a loaded truck crane. However, the work machine is not limited to a mobile crane and may be various work machines (for example, aerial work platforms) 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] When the telescopic boom 14 extends or retracts, the cylinder connecting pin and the boom connecting pin move by the power of the electric motor 41. Position information of the cylinder connecting pin and the boom connecting pin is required to control the extension or retraction of the telescopic boom.

[0018] Therefore, in this embodiment, a position information detection device 5 is provided for detecting the position information of the cylinder connecting pin and the boom connecting pin. In particular, the position information detection device 5 has two systems of detection devices (a first detection device 51 and a second detection device 52 described below).

[0019] Such a position information detection device 5 is configured to be able to detect the combination of the states of the cylinder connecting pin and the boom connecting pin.

[0020] Furthermore, the mobile crane 1 of this embodiment has a function to detect abnormalities in the position information detection device 5. In particular, the mobile crane 1 of this embodiment has a function to identify whether an abnormality has occurred in the first detection device 51 or the second detection device 52 that make up the position information detection device 5. The mobile crane 1 of this embodiment will now be described in detail.

[0021] 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.

[0022] The swivel base 12 is rotatably mounted on the upper part of the traveling body 10. The base end of the telescopic boom 14 is fixed to the swivel base 12 and is capable of raising and lowering and extending. The actuator 2 extends and retracts the telescopic boom 14. The 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.

[0023] 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. The tip boom 141, the intermediate boom 142, and the base boom 143 are also referred to as boom elements.

[0024] The telescopic boom 14 extends sequentially from the innermost boom, transitioning from the retracted state shown in FIG. 2A to the extended state shown in FIG. 1. There may be multiple intermediate booms. The tip boom 141 is cylindrical and has an internal space capable of accommodating the actuator 2. The tip boom 141 has a pair of cylinder pin receivers 141a and a pair of boom pin receivers 141b at its base end.

[0025] The pair of cylinder pin receiving portions 141a are coaxially provided at the base end of the tip boom 141. The pair of cylinder pin receiving portions 141a 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.

[0026] The cylinder connecting pins 454A, 454B are each 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 toward the base end of the cylinder connecting pins 454A, 454B) based on the operation of a cylinder connecting mechanism 45 (described later).

[0027] With the pair of cylinder connecting pins 454A, 454B engaged with the pair of cylinder pin receivers 141a, the distal boom 141 can move in the extension / retraction direction together with the cylinder member 32. The pair of boom pin receivers 141b are provided coaxially with each other and closer to the base end than the cylinder pin receiver 141a. The pair of boom pin receivers 141b respectively support a pair of boom connecting pins 144a.

[0028] Each of the pair of boom connecting pins 144a 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, which will be described later. 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 toward the base end of the boom connecting pin 144a) based on the operation of the boom connecting mechanism 46, which will be described later.

[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. In other words, the pair of boom connecting pins 144a can be engaged with and disengaged from the first boom pin receiving portion 142b or the second boom pin receiving portion 142c of the intermediate boom 142, respectively.

[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, at its base end, 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, and, at its tip end, a pair of second boom pin receiving portions 142c.

[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 141a and the pair of boom pin receiving portions 141b of the tip boom 141. 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.

[0033] 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.

[0034] The actuator 2 is an actuator that extends and retracts the telescopic boom 14. As shown in FIGS. 2 to 11C, 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. 2).

[0035] The telescopic cylinder 3 has 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.

[0036] <Pin movement mechanism> The pin moving mechanism 4 has an electric motor 41 , a brake mechanism 42 , a transmission mechanism 43 , a cylinder connecting mechanism 45 , a boom connecting mechanism 46 , and a position information detecting device 5 , all of which are supported by a trunnion 40 .

[0037] Below, each component constituting the actuator 2 will be described based on the state in which each component is incorporated into the actuator 2. In addition, a Cartesian coordinate system (X, Y, Z) is used in the description of the actuator 2. In the Cartesian coordinate system, the X direction corresponds to the extension direction of the telescopic boom 14 when it is mounted on the mobile crane 1. The positive side of the X direction is the extension direction in the telescopic direction. The negative side of the X direction is the contraction direction in the telescopic direction. When the rotation angle of the telescopic boom 14 is 0 degrees and the hoisting angle of the telescopic boom 14 is 0 degrees (fully lowered state), the positive side of the X direction corresponds to the front side of the mobile crane 1. When the rotation angle of the telescopic boom 14 is 0 degrees and the hoisting angle of the telescopic boom 14 is 0 degrees, the negative side of the X direction corresponds to the rear side of the mobile crane 1.

[0038] Furthermore, the Z direction corresponds to the up-and-down direction of the mobile crane 1, for example, when the hoisting angle of the telescopic boom 14 is 0 degrees. The Y direction corresponds to the width direction (left-right direction) of the mobile crane 1, for example, when the telescopic boom 14 is facing forward. Hereinafter, when the width direction or left-right direction is mentioned without any particular mention, it means the Y direction in the Cartesian coordinate system (X, Y, Z).

[0039] When looking at the mobile crane 1 from the rear to the front, the left side is the + side in the Y direction. When looking at the mobile crane 1 from the rear to the front, the right side is the - side in the Y direction. When looking at the mobile crane 1 from the rear to the front, the top side is the + side in the Z direction. When looking at the mobile crane 1 from the rear to the front, the bottom side is the - side in the Z direction.

[0040] The trunnion 40 will be described with reference to Figures 3 to 5. The trunnion 40 has a support hole 401. The rod member 31 of the telescopic cylinder 3 is inserted into the support hole 401 in the X direction. The trunnion 40 is fixed to the base end (the end on the negative side in the X direction) of the cylinder member 32 of the telescopic cylinder 3. Therefore, the trunnion 40 moves together with the cylinder member 32.

[0041] The trunnion 40 supports a cylinder connecting mechanism 45 and a boom connecting mechanism 46. The trunnion 40 also supports an electric motor 41, a brake mechanism 42, and a transmission mechanism 43, which will be described later. In this way, the trunnion 40 unitizes these elements. This configuration contributes to the miniaturization of the pin moving mechanism 4, improvement of productivity, and improvement of system reliability.

[0042] The trunnion 40 holds the right cylinder connecting pin 454A by a right pin support portion (not shown) provided on the right side wall. The right cylinder connecting pin 454A is movable in the left-right direction. The trunnion 40 holds the left cylinder connecting pin 454B by a left pin support portion (not shown) provided on the left side wall. The left cylinder connecting pin 454B is movable in the left-right direction.

[0043] The electric motor 41 is fixed to a vertical transmission mechanism 432 via a reducer 431. The electric motor 41 is covered with a cover 410 for waterproofing and dustproofing. As shown in Fig. 3, the electric motor 41 is provided above the trunnion 40. The reducer 431 is connected to the output shaft of the electric motor 41 (see Figs. 10A to 10C).

[0044] The electric motor 41 is connected, for example, to a power supply device (not shown) provided on the swivel base 12 via a power supply cable. The electric motor 41 is also connected, for example, to a control unit (not shown) provided on the swivel base 12 via a cable for transmitting control signals.

[0045] The brake mechanism 42 applies a braking force to the electric motor 41. When the electric motor 41 is stopped, the brake mechanism 42 prevents the rotation of the output shaft of the electric motor 41. This maintains the state of the pin moving mechanism 4 when the electric motor 41 is stopped.

[0046] 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 retracted 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 the control unit 530 (see FIGS. 10A to 11C). Alternatively, the state of the brake mechanism 42 may be switched based on an operation by an operator.

[0047] The transmission mechanism 43 transmits the power of the electric motor 41 to the cylinder connection mechanism 45 and the boom connection mechanism 46. The transmission mechanism 43 has a reducer 431 and a vertical transmission mechanism 432. The reducer 431 reduces the rotation of the electric motor 41 and transmits it to the vertical transmission mechanism 432. The vertical transmission mechanism 432 transmits the rotation of the reducer 431 to a switch gear 450 (FIGS. 10A to 10C) described below. In this embodiment, the electric motor 41 is provided above the switch gear 450. Therefore, the vertical transmission mechanism 432 is configured to transmit the rotation of the electric motor 41 to the switch gear 450, which is provided below the electric motor 41.

[0048] Specifically, the vertical transmission mechanism 432 has an upper transmission shaft 432a, a lower transmission shaft 432b, and a transmission gear (not shown). The upper transmission shaft 432a is provided coaxially with the output shaft of the electric motor 41. The upper transmission shaft 432a is connected to the reducer 431.

[0049] The lower transmission shaft 432b is an example of a rotating member that rotates based on the power of a motor, and is provided parallel to and lower than the upper transmission shaft 432a. The lower transmission shaft 432b is disposed coaxially with a switch gear 450 (described later) and is connected to the switch gear 450. Note that the rotating member that rotates based on the power of a motor is not limited to the lower transmission shaft 432b. The rotating member that rotates based on the power of a motor may be any member that rotates based on the power of the electric motor 41.

[0050] The transmission gear has an upper gear (not shown) provided on the upper transmission shaft 432a and a lower gear (not shown) provided on the lower transmission shaft 432b. The upper gear and the lower gear are external gears and mesh with each other. The rotation of the reducer 431 is transmitted to the switch gear 450 via the vertical transmission mechanism 432.

[0051] <Cylinder connection mechanism> The cylinder coupling mechanism 45 operates based on the power of the electric motor 41, and transitions between an expanded state (see FIGS. 9 and 10A) and a contracted state (see FIG. 10C). The operation of the cylinder coupling mechanism 45 transitioning from the expanded state to the contracted state is the extraction operation of the cylinder coupling mechanism 45. The operation of the cylinder coupling mechanism 45 transitioning from the contracted state to the expanded state is the engagement operation of the cylinder coupling mechanism 45.

[0052] When the cylinder connecting mechanism 45 is in the expanded state, a pair of cylinder connecting pins 454A, 454B (described later) and a pair of cylinder pin receiving portions 141a of the boom (for example, the tip boom 141) are engaged with each other. In this engaged state, the boom and the cylinder member 32 are connected.

[0053] Furthermore, when the cylinder connecting mechanism 45 is in the contracted state, the pair of cylinder connecting pins 454A, 454B and the pair of cylinder pin receiving portions 141a are in a disengaged state. In this disengaged state, the boom and the cylinder member 32 are disengaged.

[0054] Specifically, the cylinder connecting mechanism 45 includes a switch gear 450 , a first rack bar 451 , a first gear mechanism 452 , a second gear mechanism 453 , a pair of cylinder connecting pins 454 A and 454 B, and a first biasing mechanism 455 .

[0055] The switch gear 450 has teeth on a portion of its outer circumferential surface. The switch gear 450 is fitted and fixed to the outside of the lower transmission shaft 432b of the transmission mechanism 43, and rotates together with the lower transmission shaft 432b. The switch gear 450 selectively transmits the power of the electric motor 41 to either the cylinder connection mechanism 45 or the boom connection mechanism 46.

[0056] In the following description, the rotation direction of the switch gear 450 (the direction indicated by arrow A1 in FIG. 10A) when the cylinder coupling mechanism 45 transitions from the extended state to the contracted state is the first direction in the rotation directions of the switch gear 450. On the other hand, the rotation direction of the switch gear 450 (the direction indicated by arrow A2 in FIG. 10A) when the cylinder coupling mechanism 45 transitions from the contracted state to the extended state is the second direction in the rotation directions of the switch gear 450.

[0057] The first rack bar 451 moves in its longitudinal direction (Y direction) in response to the rotation of the switch gear 450. The first rack bar 451 is located closest to the + side in the Y direction when the cylinder coupling mechanism 45 is in the expanded state. On the other hand, the first rack bar 451 is located closest to the - side in the Y direction when the cylinder coupling mechanism 45 is in the contracted state.

[0058] The first rack bar 451 has a first rack tooth portion on its upper surface. The first rack tooth portion meshes with the tooth portion of the switch gear 450 only during the above-described state transition.

[0059] In the expanded state, when the switch gear 450 rotates a predetermined amount in the first direction, the teeth of the switch gear 450 mesh with the first rack teeth of the first rack bar 451. When the switch gear 450 rotates further in the first direction from this state, the first rack bar 451 moves to the right in response to the rotation of the switch gear 450.

[0060] When the switch gear 450 rotates in the second direction from the expanded state of the cylinder coupling mechanism 45, the first rack tooth portion of the first rack bar 451 and the tooth portion of the switch gear 450 do not mesh with each other.

[0061] The first rack bar 451 has a second rack tooth portion and a third rack tooth portion on its underside. 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).

[0062] The first gear mechanism 452 has a plurality of gears (see FIG. 9), each of which is an external gear. The first gear mechanism 452 meshes with the second rack tooth portion of the first rack bar 451. 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 the pin-side rack tooth portion of the right-side cylinder connecting pin 454A, which will be described later.

[0063] The second gear mechanism 453 has a plurality of gears (see FIG. 9), each of which is an external gear. The second gear mechanism 453 meshes with the third rack tooth portion of the first rack bar 451. The second gear mechanism 453 rotates in response to the movement of the first rack bar 451. The second gear mechanism 453 also meshes with the pin-side rack tooth portion of the left cylinder connecting pin 454B, which will be described later.

[0064] 9 and 10A to 10C, the pair of cylinder connecting pins 454A, 454B have respective central axes aligned in the left-right direction and are coaxial with each other. Each of the pair of cylinder connecting pins 454A, 454B corresponds to an example of a first pin.

[0065] The right cylinder connecting pin 454A has a pin-side rack tooth portion on its outer circumferential surface. The pin-side rack tooth portion of the right cylinder connecting pin 454A meshes with the first gear mechanism 452. The left cylinder connecting pin 454B has a pin-side rack tooth portion on its outer circumferential surface. The pin-side rack tooth portion of the left cylinder connecting pin 454B meshes with the second gear mechanism 453.

[0066] The right cylinder connecting pin 454A having the above-described configuration is supported by the right wall portion of the trunnion 40. The axial (left-right) movement of the right cylinder connecting pin 454A is guided by the right wall portion of the trunnion 40.

[0067] The left cylinder connecting pin 454B is supported by the left wall portion of the trunnion 40. The axial movement of the left cylinder connecting pin 454B is guided by the left wall portion. The right cylinder connecting pin 454A moves in its own axial direction in response to the rotation of the first gear mechanism 452. Specifically, the right cylinder connecting pin 454A moves to the right (outside) when the cylinder connecting mechanism 45 transitions from the contracted state (see FIG. 10C) to the expanded state (see FIG. 10A). On the other hand, the right cylinder connecting pin 454A moves to the left (inside) when transitioning from the expanded state (see FIG. 10A) to the contracted state (see FIG. 10C).

[0068] The left cylinder connecting pin 454B moves in its axial direction in response to rotation of the second gear mechanism 453. Specifically, the left cylinder connecting pin 454B moves to the left when the cylinder connecting mechanism 45 transitions from the contracted state (see FIG. 10C) to the expanded state (see FIG. 10A). On the other hand, the left cylinder connecting pin 454B moves to the right when the cylinder connecting mechanism 45 transitions from the expanded state (see FIG. 10A) to the contracted state (see FIG. 10C).

[0069] When the cylinder connecting pins 454A, 454B move outward from their contracted state, the tips of the cylinder connecting pins 454A, 454B protrude outward from both left and right side surfaces of the trunnion 40. The state in which the cylinder connecting pins 454A, 454B have moved to the outwardmost position is referred to as the expanded state of the cylinder connecting pins 454A, 454B. In the expanded state, the cylinder connecting pins 454A, 454B engage with the cylinder pin receiving portions of the boom.

[0070] The first biasing mechanism 455 returns the cylinder linking mechanism 45 to the extended state when the electric motor 41 is de-energized while the cylinder linking mechanism 45 is in the contracted state. In other words, the first biasing mechanism 455 returns the pair of cylinder linking pins 454A, 454B to the reference positions when the electric motor 41 is de-energized (stopped) and the brake mechanism 42 is turned off while the cylinder linking mechanism 45 is in the contracted state.

[0071] Specifically, the first biasing mechanism 455 is an example of a first spring and has a pair of coil springs 455a, 455b (see FIGS. 10A to 10C). The right coil spring 455a constantly biases the right cylinder connecting pin 454A. The direction in which the right coil spring 455a biases the cylinder connecting pin 454A coincides with the direction from the base end to the tip end of the cylinder connecting pin 454A (to the right).

[0072] The left coil spring 455b constantly biases the left cylinder connecting pin 454B. The direction in which the left coil spring 455b biases the left cylinder connecting pin 454B coincides with the direction from the base end to the tip end (left side) of the cylinder connecting pin 454B. 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, 455b is not limited to that of this embodiment. The operation of the cylinder connecting mechanism 45 will be described later.

[0073] <Boom connection mechanism> The boom connection mechanism 46 transitions between an extended state (see FIG. 11A) and a retracted state (see FIG. 11C) based on the rotation of the electric motor 41. The operation of the boom connection mechanism 46 transitioning from the extended state to the retracted state is the retracting 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 retracting operation of the boom connection mechanism 46.

[0074] 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. The boom connection pin is an example of a second pin.

[0075] 9 and 11A to 11C, the boom connection mechanism 46 has a switch gear 450, a pair of second rack bars 461a, 461b, a synchronization gear 462, and a second biasing mechanism 463. The switch gear 450 is a gear common to the cylinder connection mechanism 45.

[0076] 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.

[0077] The pair of second rack bars 461a, 461b each have a synchronizing rack tooth portion on its opposing surface. Each of the synchronizing rack tooth portions is meshed with a synchronizing gear 462 (see FIGS. 11A to 11C). When the synchronizing gear 462 rotates, one (front) second rack bar 461a and the other (rear) second rack bar 461b move in opposite directions in the left-right direction.

[0078] The pair of second rack bars 461a, 461b have locking claws 461g, 461h (see FIG. 9) at their tips, respectively. When moving a boom connecting pin (for example, boom connecting pins 144a, 144b), the locking claws 461g, 461h engage with pin side receiving portions 144c (see FIG. 9) provided on the boom connecting pin.

[0079] One of the second rack bars 461a has a driving rack tooth portion 461c (see FIG. 9) on a surface facing the switch gear 450. The driving rack tooth portion 461c meshes with the tooth portion of the switch gear 450 when the switch gear 450 rotates a predetermined amount in the second direction (the direction indicated by arrow A2 in FIG. 9).

[0080] When the switch gear 450 rotates a predetermined amount in the second direction from the extended state of the boom coupling mechanism 46, the drive rack tooth portion 461c meshes with the tooth portion of the switch gear 450. When the switch gear 450 rotates further in the second direction, one second rack bar 461a moves to the right based on the meshing of the drive rack tooth portion 461c with the tooth portion of the switch gear 450. Furthermore, when one second rack bar 461a moves to the right, the synchronization gear 462 rotates, and the other second rack bar 461b moves to the left.

[0081] 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.

[0082] Specifically, the second biasing mechanism 463 is configured by a pair of coil springs 463a, 463b (see FIGS. 11A to 11C). 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.

[0083] <Operation of the linkage mechanism> An example of the operation of the cylinder connecting mechanism 45 and the boom connecting mechanism 46 will now be described.

[0084] <Operation of the cylinder linkage mechanism> 2A to 2E and 10A to 10C, a description will be given of an example of the operation of the cylinder coupling mechanism 45. 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.

[0085] Fig. 10A is a schematic diagram showing the expanded state of the cylinder coupling mechanism 45, and the state in which the pair of cylinder coupling pins 454A, 454B are engaged with the pair of cylinder pin receivers 141a of the tip boom 141. Fig. 10B is a schematic diagram showing the state in which the cylinder coupling mechanism 45 is in the middle of transitioning from the expanded state to the contracted state. Furthermore, Fig. 10C is a schematic diagram showing the contracted state of the cylinder coupling mechanism 45, and the state in which the pair of cylinder coupling pins 454A, 454B are disengaged from the pair of cylinder pin receivers 141a of the tip boom 141.

[0086] The expanded state of the cylinder linking mechanism 45 shown in Fig. 10A corresponds to the state of the cylinder linking mechanism 45 in Fig. 2A to Fig. 2D. The state of the cylinder linking mechanism 45 shown in Fig. 10B corresponds to a state in which the cylinder linking mechanism 45 is transitioning from the state shown in Fig. 2D to the state shown in Fig. 2E. The contracted state of the cylinder linking mechanism 45 shown in Fig. 10C corresponds to the state of the cylinder linking mechanism 45 shown in Fig. 2E.

[0087] When the cylinder linking mechanism 45 transitions from the extended state to the retracted state, the control unit 530 (see FIGS. 10A to 11C) 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. Note that the control unit 530 may actually be configured in such a way that a CPU, ROM, RAM, HDD, etc. are connected via a bus, or may be configured with a one-chip LSI, etc.

[0088] 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 450 → First rack bar 451 → First gear mechanism 452 → Right cylinder connecting pin 454A

[0089] 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 450 → First rack bar 451 → Second gear mechanism 453 → Left cylinder connecting pin 454B

[0090] Specifically, first, in the first transmission path and the second transmission path, the switch gear 450 rotates in a first direction (the direction indicated by the arrow A1 in FIG. 10A) based on the power of the electric motor 41. At this time, the lower transmission shaft 432b of the vertical transmission mechanism 432 rotates together with the switch gear 450 in the first direction.

[0091] In the first transmission path, when the switch gear 450 rotates in the first direction, the first rack bar 451 moves to the right in response to the rotation. Then, 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.

[0092] The position information detection device 5, which will be described later, detects that the pair of cylinder connecting pins 454A, 454B have disengaged from the pair of cylinder pin receivers 141a of the tip boom 141 and moved to a predetermined position (for example, the position shown in FIG. 10C). In other words, the position information detection device 5 detects the combination of the states of the pair of cylinder connecting pins 454A, 454B and the pair of boom connecting pins (for example, boom connecting pin 144a). Then, based on the detection result, the control unit 530 (see FIGS. 10A to 11C) turns on the brake mechanism 42 and turns off the electric motor 41, thereby stopping the operation of the cylinder connecting mechanism 45.

[0093] In addition, the transition of the cylinder connecting mechanism 45 from the contracted state to the expanded state is automatically performed based on the biasing force of the first biasing mechanism 455 when the brake mechanism 42 is in the OFF state while the electric motor 41 is not energized.

[0094] <Boom connection mechanism operation> Next, an example of the operation of the boom connecting mechanism 46 will be described with reference to FIGS. 2A to 2E and 11A to 11C.

[0095] Fig. 11A 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. 11B 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. 11C 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.

[0096] The extended state of the boom connection mechanism 46 shown in Fig. 11A corresponds to the state of the boom connection mechanism 46 in Fig. 2A. The state of the boom connection mechanism 46 shown in Fig. 11B 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. 11C corresponds to the state of the boom connection mechanism 46 shown in Fig. 2B.

[0097] 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 450 shown in FIG.

[0098] When the boom connection mechanism 46 transitions from the extended state to the retracted state, the control unit 530 (see FIGS. 10A to 11C) drives the electric motor 41 in the direction opposite to that for operating the cylinder connection mechanism 45. The power of the electric motor 41 is transmitted through the following path. (Transmission path) Switch gear 450 → one second rack bar 461a → synchronous gear 462 → other second rack bar 461b

[0099] First, in the transmission path, the switch gear 450 rotates in a second direction (the direction indicated by arrow A2 in FIG. 11A) in the rotational direction of the switch gear 450 based on the power of the electric motor 41. At this time, the lower transmission shaft 432b of the vertical transmission mechanism 432 rotates in the second direction together with the switch gear 450. When the switch gear 450 rotates in the second direction, one of the second rack bars 461a moves to the right in response to the rotation.

[0100] 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.

[0101] 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 11C).

[0102] The position information detection device 5, which will be described later, detects that the pair of boom connecting pins 144a have disengaged from the pair of first boom pin receivers 142b of the intermediate boom 142 and moved to a predetermined position (for example, the position shown in FIG. 11C). Then, based on this detection result, the control unit 530 turns on the brake mechanism 42 and turns off the electric motor 41, thereby stopping the operation of the boom connecting mechanism 46.

[0103] When the brake mechanism 42 is turned off while the electric motor 41 is not energized, the closing operation of the boom connection mechanism 46 is automatically performed based on the biasing force of the second biasing mechanism 463. During this state transition, the pair of boom connection pins 144a move in directions away from each other.

[0104] The position information detection device 5, which will be described later, detects that the pair of boom connecting pins 144a are engaged with the pair of first boom pin receiving portions 142b of the intermediate boom 142 and have moved to a predetermined position (for example, the position shown in FIG. 11A). The detection result is used to control the next operation of the actuator 2.

[0105] The position information detecting device 5 detects information relating to the positions of the pair of cylinder connecting pins 454A, 454B and the pair of boom connecting pins 144a, 144b. In other words, the position information detecting device 5 detects the combination of the states of the pair of cylinder connecting pins 454A, 454B and the pair of boom connecting pins (for example, boom connecting pin 144a).

[0106] First, a description will be given of the configuration of the position information detecting device 5. The position information detecting device 5 has a support 50, a first detecting device 51, a second detecting device 52, and a cover member .

[0107] The first detection device 51 and the second detection device 52 are supported on the trunnion 40 by a support 50. The first detection device 51 and the second detection device 52 detect information relating to the positions of the pair of cylinder connecting pins 454A, 454B and the pair of boom connecting pins 144a, 144b using different detection methods.

[0108] Under normal circumstances, only one of the first detecting device 51 and the second detecting device 52 detects information relating to the positions of the pair of cylinder connecting pins 454A, 454B and the pair of boom connecting pins 144a, 144b. Then, for example, when the control unit 530 (see FIGS. 10A to 11C) detects a failure (abnormality) of one of the detecting devices, the other of the first detecting device 51 and the second detecting device 52 detects information relating to the positions of the pair of cylinder connecting pins 454A, 454B and the pair of boom connecting pins 144a, 144b.

[0109] It is preferable that the one detection device is the second detection device 52 and the other detection device is the first detection device 51. However, the one detection device may be the first detection device 51 and the other detection device may be the second detection device 52. Furthermore, under normal circumstances, the first detection device 51 and the second detection device 52 may detect information relating to the positions of the pair of cylinder connecting pins 454A, 454B and the pair of boom connecting pins 144a, 144b.

[0110] In this embodiment, under normal circumstances, the first detector 51 and the second detector 52 detect the combination of the states of the pair of cylinder connecting pins 454A, 454B and the pair of boom connecting pins 144a, 144b. Then, the control unit 530 controls the extension and retraction operation of the telescopic boom 14 based on the detection result of the second detector 52.

[0111] Note that the first detector 51 and the second detector 52 cannot detect their own failure (abnormality) by themselves. Therefore, the control unit 530 may determine that a failure (abnormality) has occurred in at least one of the detectors, the first detector 51 and the second detector 52, when there is a discrepancy (for example, a deviation of a predetermined value or more) between the detected value of the first detector 51 and the detected value of the second detector 52.

[0112] Furthermore, during normal control, the control unit 530 may detect information relating to the positions of the pair of cylinder connecting pins 454A, 454B and the pair of boom connecting pins 144a, 144b based on the detection value of the second detection device 52, while determining whether the detection devices have a malfunction based on the detection values ​​of the first detection device 51 and the second detection device 52. The method of determining the malfunction (abnormality detection control) will be described later.

[0113] At this time, the first detecting device 51 may or may not detect information relating to the positions of the pair of cylinder connecting pins 454A, 454B and the pair of boom connecting pins 144a, 144b. Furthermore, when the control unit 530 is able to identify, through the failure determination, that a failure (abnormality) has occurred in the second detecting device 52, the control unit 530 may detect information relating to the positions of the pair of cylinder connecting pins 454A, 454B and the pair of boom connecting pins 144a, 144b based on the detection value of the first detecting device 51.

[0114] The support 50 is a member that supports the first detection device 51 and the second detection device 52 on the trunnion 40. The support 50 is fixed to the trunnion 40. Specifically, the support 50 is fixed to the rear side surface (the side surface on the negative side in the X direction) of the trunnion 40.

[0115] The support 50 has a right side plate 501, a left side plate 502, a rear side plate 503, a right fixed plate 504, and a left fixed plate 505. The right side plate 501 is a plate parallel to the XZ plane. The left side plate 502 is a plate parallel to the XZ plane. The right side plate 501 and the left side plate 502 are spaced apart and face each other in the left-right direction (Y direction). The right side plate 501 and the left side plate 502 each correspond to an example of a first plate portion.

[0116] The rear plate 503 is an example of a second plate portion and is a plate parallel to the YZ plane. The rear plate 503 connects the rear end (the end on the negative side in the X direction) of the right plate 501 and the rear end (the end on the negative side in the X direction) of the left plate 502 in the left-right direction. In other words, the support 50 is a U-shaped plate member that opens in the vertical direction and also opens forward. The space surrounded by the right plate 501, left plate 502, and rear plate 503 of the support 50 is a storage space 506. The storage space 506 may be considered to be a space defined by the support 50.

[0117] The right fixed plate 504 is a plate parallel to the YZ plane and is fixed to the front end of the right plate 501.

[0118] The left fixed plate 505 is a plate parallel to the YZ plane and is fixed to the front end of the left plate 502.

[0119] The front ends of the support 50 (front ends of the right and left plates) are fixed to the rear side of the trunnion 40 via a right fixed plate 504 and a left fixed plate 505. In this state, the right fixed plate 504 and the left fixed plate 505 are each positioned relative to the trunnion 40 by positioning pins 507 inserted into the fixed portions 400 on the trunnion side. This configuration contributes to improving the efficiency of the assembly work when assembling the support 50 to the trunnion 40.

[0120] Furthermore, the lower transmission shaft 432b is disposed between the right side plate 501 and the left side plate 502 of the support 50. In other words, the lower transmission shaft 432b is disposed in the accommodation space 506. The right side plate 501 and the left side plate 502 are parallel to the lower transmission shaft 432b.

[0121] The first detection device 51 has a first detection object 510, a second detection object 511, a first sensor 512, a second sensor 513, and a third sensor 514. The first detection device 51 corresponds to an example of a sub-detection device. The first detection device 51 detects information relating to the positions of the pair of cylinder connecting pins 454A, 454B and the pair of boom connecting pins 144a, 144b based on a combination of outputs (detection values) of the first sensor 512, the second sensor 513, and the third sensor 514.

[0122] The first detectable object 510 is fixed to the lower transmission shaft 432b with the lower transmission shaft 432b inserted through the center hole. In other words, the first detectable object 510 is disposed in the accommodation space 506. The first detectable object 510 rotates together with the lower transmission shaft 432b. The first detectable object 510 has a first cylindrical surface 510a and a first flat surface 510b on its outer circumferential surface.

[0123] The first cylindrical surface 510a corresponds to an example of a first detectable surface of the first detectable object. The first cylindrical surface 510a is a cylindrical surface having a predetermined outer diameter and provided on a portion (also referred to as a first portion) of the outer peripheral surface of the first detectable object 510. The first flat surface 510b corresponds to an example of a second detectable surface of the first detectable object. The first flat surface 510b is a flat surface provided on the remaining portion (also referred to as a second portion) of the outer peripheral surface of the first detectable object 510. The shapes of the first detectable surface of the first detectable object and the second detectable surface of the first detectable object are not limited to those of this embodiment. The shapes of the first detectable surface of the first detectable object and the second detectable surface of the first detectable object may be distinguishable from each other (i.e., different shapes).

[0124] 13, in the neutral state, first cylindrical surface 510a is located in the lower half and first flat surface 510b is located in the upper half of first detection object 510. The neutral state of first detection object 510 corresponds to the engaged state of the pair of cylinder connecting pins 454A, 454B and boom connecting pin 144a (see FIGS. 2A to 2E).

[0125] The second detectable object 511 is fixed to the lower transmission shaft 432b with the lower transmission shaft 432b inserted through the center hole. That is, the second detectable object 511 is disposed in the accommodation space 506. The second detectable object 511 rotates together with the lower transmission shaft 432b. The second detectable object 511 is disposed forward of the first detectable object 510. The second detectable object 511 has a second cylindrical surface 511a and a second flat surface 511b on its outer circumferential surface.

[0126] The second cylindrical surface 511a corresponds to an example of the first detectable surface of the second detectable object. The second cylindrical surface 511a is a cylindrical surface having a predetermined outer diameter and provided on a portion (also referred to as the first portion) of the outer circumferential surface of the second detectable object 511. The second flat surface 511b corresponds to an example of the second detectable surface of the second detectable object. The second flat surface 511b is a flat surface provided on the remaining portion (also referred to as the second portion) of the outer circumferential surface of the second detectable object 511. The shapes of the first detectable surface of the second detectable object and the second detectable surface of the second detectable object are not limited to those of this embodiment. The shapes of the first detectable surface of the second detectable object and the second detectable surface of the second detectable object may be distinguishable from each other (i.e., different shapes).

[0127] 13, in the neutral state, the second cylindrical surface 511a is located on the left half portion and the second flat surface 511b is located on the right half portion of the second detectable object 511. The neutral state of the second detectable object 511 corresponds to the engaged state of the pair of cylinder connecting pins 454A, 454B and the boom connecting pin 144a (see FIGS. 2A to 2E). The neutral state of the second detectable object 511 corresponds to the extended state of the cylinder connecting mechanism 45 and the extended state of the boom connecting mechanism 46, as shown in FIGS. 10A and 11A.

[0128] The first sensor 512, the second sensor 513, and the third sensor 514 are each an example of a first detection unit and are non-contact proximity sensors. The first sensor 512, the second sensor 513, and the third sensor 514 are each supported by the support 50.

[0129] Specifically, the first sensor 512 is supported by the right side plate 501 of the support 50. The tip of the first sensor 512 faces the outer peripheral surface of the first detectable object 510 in the left-right direction. The first sensor 512 outputs an electric signal according to the distance from the outer peripheral surface of the first detectable object 510.

[0130] For example, the output of the first sensor 512 is turned ON when it faces the first cylindrical surface 510a of the first detection object 510. On the other hand, the output of the first sensor 512 is turned OFF when it faces the first flat surface 510b of the first detection object 510.

[0131] The second sensor 513 is supported by the left side plate 502 of the support 50. The tip of the second sensor 513 faces the outer peripheral surface of the first detectable object 510 in the left-right direction. The first sensor 512 and the second sensor 513 face each other in the left-right direction. The second sensor 513 outputs an electrical signal according to the distance from the outer peripheral surface of the first detectable object 510.

[0132] For example, the output of second sensor 513 is turned ON when it faces first cylindrical surface 510a of first detection object 510. On the other hand, the output of first sensor 512 is turned OFF when it faces first flat surface 510b of first detection object 510.

[0133] The third sensor 514 is supported by the right side plate 501 of the support 50. The third sensor 514 is disposed on the right side plate 501 of the support 50, further forward than the first sensor 512. The tip of the third sensor 514 faces the outer peripheral surface of the second object to be detected 511 in the left-right direction. The third sensor 514 outputs an electric signal according to the distance from the outer peripheral surface of the second object to be detected 511. The third sensor 514 may be supported by the left side plate 502 of the support 50. The position of the third sensor 514 is not limited to that shown in the figure.

[0134] For example, the output of the third sensor 514 is turned ON when it faces the second cylindrical surface 511a of the second object to be detected 511. On the other hand, the output of the third sensor 514 is turned OFF when it faces the second flat surface 511b of the second object to be detected 511.

[0135] The second detection device 52 is a non-contact potentiometer and includes a detection object 520 and a sensor 521. The second detection device 52 corresponds to an example of a main detection device. The detection object 520 is a magnet, and is fixed to the lower transmission shaft 432b with the rear end of the lower transmission shaft 432b inserted into the center hole. Therefore, the detection object 520 rotates together with the lower transmission shaft 432b. In addition, the detection object 520 is arranged rearward of the first detection object 510 of the first detection device 51.

[0136] The sensor 521 corresponds to an example of a second detection unit, has a Hall element, and is supported by the rear plate 503 of the support 50.

[0137] As described above, in this embodiment, the first sensor 512, second sensor 513, and third sensor 514 of the first detection device 51, and the sensor 521 of the second detection device 52 are supported by the support 50. In other words, the support 50 unitizes the first sensor 512, second sensor 513, and third sensor 514 of the first detection device 51, and the sensor 521 of the second detection device 52. Therefore, by removing the support 50 from the trunnion 40, the sensors 512, 513, 514, and 521 can be removed together from the trunnion 40. This configuration contributes to improved assembly efficiency and improved maintenance efficiency.

[0138] Furthermore, the detection surfaces of the sensors 512, 513, 514, and 521 are disposed in the accommodation space 506 surrounded by the support 50. This configuration can prevent damage to the detection surfaces of the sensors 512, 513, 514, and 521.

[0139] The sensor 521 faces the detection object 520 in the front-rear direction. The sensor 521 outputs a voltage (see FIG. 15) according to the phase of the detection object 520. In other words, the sensor 521 outputs a voltage according to the rotation angle of the lower transmission shaft 432b to which the detection object 520 is fixed.

[0140] In this embodiment, the method (detection system) by which the first detector 51 detects information related to the position is different from the method (detection system) by which the second detector 52 detects information related to the position. In other words, the pin moving mechanism 4 according to this embodiment has two systems of detection mechanisms that use different detection methods to detect information related to the positions of the pair of cylinder connecting pins 454A, 454B and the pair of boom connecting pins 144a, 144b. The second detector may be a contact potentiometer or an encoder.

[0141] The cover member 54 is, for example, a rectangular plate member parallel to the XY plane. As shown in Figures 7 and 8, the cover member 54 covers the upper opening of the support 50 from above. Note that the cover member 54 is omitted in Figure 6.

[0142] The cover member 54 is fixed to the upper end of the support 50 or to the trunnion 40. Such a cover member 54 prevents foreign matter from entering the accommodation space 506 through the upper opening of the support 50. Furthermore, as shown in FIGS. 7 and 8, the lower opening of the support 50 faces the surface of the telescopic cylinder 3 (specifically, the rod member 31) at a predetermined distance. This configuration prevents foreign matter from entering the accommodation space 506 through the lower opening of the support 50.

[0143] For example, if foreign matter adheres to the detection surfaces of the first sensor 512, the second sensor 513, and the third sensor 514 of the first detection device 51, false detection may occur in each of the sensors 512, 513, and 514, which may reduce the reliability of the detection results. In the present embodiment, foreign matter is prevented from entering the accommodation space 506 from the upper and lower openings of the support 50, so that the reliability of the detection results of the first detection device 51 and the second detection device 52 can be ensured.

[0144] Furthermore, since the lower opening of the accommodation space 506 faces the surface of the telescopic cylinder 3, even if the first detectable object 510 and the second detectable object 511 of the first detection device 51, or the detectable object 520 of the second detection device 52, falls off the lower transmission shaft 432b, the detectable objects 510, 511, 520 can be prevented from falling off downward.

[0145] In the position information detection device 5 as described above, under normal circumstances, the first detection device 51 and the second detection device 52 detect information regarding the positions of the pair of cylinder connecting pins 454A, 454B and the boom connecting pin 144a. Then, based on the detection result of the second detection device 52, the control unit 530 controls the extension and retraction operation of the telescopic boom 14 based on the detection result of the first detection device 51 when a failure (abnormality) of the second detection device 52 is detected. Note that under normal circumstances, only the second detection device 52 may detect information regarding the positions of the pair of cylinder connecting pins 454A, 454B and the boom connecting pin 144a. In this case, when the control unit 530 detects a failure (abnormality) of the second detection device 52, the control unit 530 may start detecting information regarding the positions of the pair of cylinder connecting pins 454A, 454B and the boom connecting pin 144a using the first detection device 51.

[0146] Here, the operation of the position information detecting device 5 will be described with reference to Fig. 12 and Fig. 13. Fig. 12 is a timing chart showing the extension operation of the tip boom 141 of the telescopic boom 14. Fig. 13 is a diagram showing the relationship between the states of the pair of cylinder connecting pins 454A, 454B and the boom connecting pin 144a and the states of the first detecting device 51 and the second detecting device 52.

[0147] The following description will be given only of the extension operation of the tip boom 141 of the telescopic boom 14. The retraction operation of the tip boom 141 is the reverse of the procedure of the telescopic operation described below.

[0148] In the following description, the state transitions between the extended state and the retracted state of the cylinder coupling mechanism 45 and the boom coupling mechanism 46 are as described above, so a detailed description of the state transitions of the cylinder coupling mechanism 45 and the boom coupling mechanism 46 will be omitted.

[0149] Furthermore, a control unit (not shown) controls the ON / OFF switching of the electric motor 41 and the ON / OFF switching of the brake mechanism 42 based on the output of the position information detection device 5.

[0150] 2A shows the retracted state of the telescopic boom 14. In this state, the tip boom 141 is connected to the intermediate boom 142 via a boom connecting pin 144a. Therefore, the tip boom 141 cannot be displaced in the longitudinal direction (left and right direction in FIG. 2) relative to the intermediate boom 142.

[0151] 2A, the tip portions of the pair of cylinder connecting pins 454A, 454B engage with the pair of cylinder pin receiving portions 141a of the tip boom 141. In other words, the tip boom 141 and the cylinder member 32 are in a connected state.

[0152] In the state of FIG. 2A, the states of the members are as follows (see T0 to T1 in FIG. 12). Brake mechanism 42: OFF Electric motor 41: OFF Cylinder coupling mechanism 45: extended state Boom linkage 46: extended state Cylinder connecting pins 454A and 454B: in position Boom connecting pin 144a: in position

[0153] In the state shown in Fig. 2A, the first detector 51 and the second detector 52 of the position information detecting device 5 are in a neutral state as shown in Fig. 13. When the first detector 51 and the second detector 52 are in a neutral state, the cylinder connecting pins 454A and 454B are in an in-position state, and the boom connecting pin 144a is in an in-position state. This combination of states is a first set of combinations of the states of the cylinder connecting pins and the boom connecting pins.

[0154] When the first detection device 51 is in the neutral state, the first sensor 512 and the second sensor 513 face the first cylindrical surface 510a of the first detection object 510. Therefore, the outputs of the first sensor 512 and the second sensor 513 are ON. On the other hand, when the first detection device 51 is in the neutral state, the third sensor 514 faces the second flat surface 511b of the second detection object 511. Therefore, the output of the third sensor 514 is OFF.

[0155] When the outputs of the first sensor 512 and the second sensor 513 are ON and the output of the third sensor 514 is OFF, the first detecting device 51 detects that the pair of cylinder connecting pins 454A, 454B are in the ON state and that the boom connecting pin 144a is in the ON state. When the first detecting device 51 is in the neutral state, the switch gear 450 is located at the reference position shown in FIGS. 10A and 11A.

[0156] Furthermore, when the second detection device 52 is in the neutral state, the rotation angle of the detection object 520 is 0 degrees. When the second detection device 52 is in the neutral state, the sensor 521 is configured to output a predetermined voltage corresponding to the neutral state (hereinafter referred to as the neutral voltage). When the second detection device 52 is in the neutral state, the switch gear 450 is located in the reference position shown in FIGS. 10A and 11A.

[0157] When the output of the sensor 521 is a neutral voltage, the second detection device 52 detects that the pair of cylinder connecting pins 454A, 454B are in the closed state and the boom connecting pin 144a is in the closed state.

[0158] Next, in the state shown in Fig. 2A, the electric motor 41 is rotated forward (in the direction indicated by arrow A2 in Fig. 11A), and the boom connection mechanism 46 of the actuator 2 displaces the pair of boom connection pins 144a in a direction in which they separate from the pair of first boom pin receivers 142b of the intermediate boom 142. At this time, the boom connection mechanism 46 transitions from the extended state to the retracted state.

[0159] When the state transitions from FIG. 2A to FIG. 2B, the states of the components are as follows (see T1 to T2 in FIG. 12). Brake mechanism 42: OFF Electric motor 41: ON (forward rotation) Cylinder coupling mechanism 45: extended state Boom connection mechanism 46: Extended state → Retracted state Cylinder connecting pins 454A and 454B: in position Boom connecting pin 144a: engaged state → disengaged state

[0160] When the boom connecting pin 144a is transitioning from the engaged state to the disengaged state, the first detection device 51 and the second detection device 52 of the position information detection device 5 transition from the neutral state to the second state in accordance with the rotation of the lower transmission shaft 432b, as shown in Figure 13.

[0161] When the first detection device 51 is transitioning from the neutral state to the second state, the first sensor 512 faces the first cylindrical surface 510a of the first detection object 510. Therefore, the output of the first sensor 512 is ON. On the other hand, the second sensor 513 faces the first flat surface 510b of the first detection object 510. Therefore, the output of the second sensor 513 is OFF.

[0162] Furthermore, when the first detection device 51 is transitioning from the neutral state to the second state, the third sensor 514 faces the second flat surface 511b of the second detection object 511. Therefore, the output of the third sensor 514 is OFF.

[0163] In this way, the first detection device 51 detects that the boom connecting pin 144a is transitioning from the engaged state to the disengaged state when the output of the first sensor 512 is ON, the output of the second sensor 513 is OFF, and the output of the third sensor 514 is OFF.

[0164] When the boom connecting pin 144a is in the withdrawn state, the first detecting device 51 is in the second state. In other words, when the first detecting device 51 is in the second state, the boom connecting pin 144a is in the withdrawn state (the state shown in FIG. 2B).

[0165] In the second state of the first detection device 51, the first sensor 512 faces the first cylindrical surface 510a of the first detection object 510. Therefore, the output of the first sensor 512 is ON. On the other hand, in the second state of the first detection device 51, the second sensor 513 faces the first flat surface 510b of the first detection object 510. Therefore, the output of the second sensor 513 is OFF.

[0166] Furthermore, in the second state of the first detection device 51, the third sensor 514 faces the second cylindrical surface 511a of the second detection object 511. Therefore, the output of the third sensor 514 is ON.

[0167] In this way, the first detection device 51 detects that the boom connecting pin 144a has been removed when the output of the first sensor 512 is ON, the output of the second sensor 513 is OFF, and the output of the third sensor 514 is ON.

[0168] When the second detection device 52 is transitioning from the neutral state to the second state, the output of the sensor 521 changes according to the phase of the detection target 520. Here, the sensor 521 is configured to output a predetermined voltage (hereinafter referred to as the second voltage) corresponding to the second state. Therefore, when the second detection device 52 is transitioning from the neutral state to the second state, the output of the sensor 521 changes from the neutral voltage to the second voltage. When the output of the sensor 521 changes from the neutral voltage to the second voltage, the second detection device 52 detects that the boom connecting pin 144a is transitioning from the engaged state to the disengaged state.

[0169] When the boom connecting pin 144a enters the uncoupled state, the second detecting device 52 enters the second state. Conversely, when the second detecting device 52 enters the second state, the boom connecting pin 144a enters the uncoupled state. When the second detecting device 52 enters the second state, the output of the sensor 521 becomes a second voltage. When the output of the sensor 521 becomes the second voltage, the second detecting device 52 detects that the boom connecting pin 144a has entered the uncoupled state.

[0170] When the boom connecting pin 144a is in the removed state, the pair of boom connecting pins 144a are disengaged from the pair of first boom pin receivers 142b of the intermediate boom 142 (see FIG. 2B). When the first detection device 51 and / or the second detection device 52 detects that the boom connecting pin 144a is in the removed state, the control unit turns on the brake mechanism 42 and turns off the electric motor 41, thereby stopping the operation of the boom connecting mechanism 46.

[0171] The timing for turning off the electric motor 41 and the timing for turning on the brake mechanism 42 are appropriately controlled by the control unit. For example, although not shown in the drawings, after the brake mechanism 42 is turned on, the electric motor 41 is turned off.

[0172] In the state of FIG. 2B, the states of the components are as follows (see T2 in FIG. 12): Brake mechanism 42: ON Electric motor 41: OFF Cylinder coupling mechanism 45: extended state Boom linkage 46: Retracted state Cylinder connecting pins 454A and 454B: in position Boom connecting pin 144a: Removed

[0173] In the second state (see FIG. 13) of the first detecting device 51 and the second detecting device 52, the cylinder connecting pins 454A, 454B are in the engaged state, and the boom connecting pin 144a is in the disengaged state. This combination of states is a second set of combinations of the states of the cylinder connecting pins and the boom connecting pins.

[0174] Next, in the state shown in Fig. 2B, pressure oil is supplied to the extension-side hydraulic chamber of the telescopic cylinder 3 of the actuator 2. This causes the cylinder member 32 to be displaced in the extension direction (to the left in Fig. 2).

[0175] As the cylinder member 32 is displaced as described above, the tip boom 141 is displaced in the extension direction (see FIG. 2C). At this time, the state of each part is maintained from T2 in FIG. 12 until T3.

[0176] 2C, the brake mechanism 42 is released. Then, based on the biasing force of the second biasing mechanism 463, the boom connection mechanism 46 displaces the pair of boom connection pins 144a in a direction in which they engage with the pair of second boom pin receiving portions 142c of the intermediate boom 142. At this time, the boom connection mechanism 46 transitions from the contracted state to the extended state (i.e., automatically returns).

[0177] When the state transitions from FIG. 2C to FIG. 2D, the states of the components are as follows (see T3 to T4 in FIG. 12). Brake mechanism 42: OFF Electric motor 41: OFF Cylinder coupling mechanism 45: extended state Boom linkage mechanism 46: Retracted state → Extended state Cylinder connecting pins 454A and 454B: in position Boom connecting pin 144a: Removed state → Installed state

[0178] When the boom connecting pin 144a is transitioning from the unloaded state to the loaded state, the first detection device 51 and the second detection device 52 of the position information detection device 5 transition from the second state to the neutral state in accordance with the rotation of the lower transmission shaft 432b, as shown in Figure 13.

[0179] When the first detection device 51 is transitioning from the second state to the neutral state, the first sensor 512 faces the first cylindrical surface 510a of the first detection object 510. Therefore, the output of the first sensor 512 is ON. On the other hand, the second sensor 513 faces the first flat surface 510b of the first detection object 510. Therefore, the output of the second sensor 513 is OFF.

[0180] Furthermore, when the first detection device 51 is transitioning from the second state to the neutral state, the third sensor 514 faces the second flat surface 511b of the second detection object 511. Therefore, the output of the third sensor 514 is OFF.

[0181] When the boom connecting pin 144a is in the on state, the first detecting device 51 is in the neutral state. Conversely, when the first detecting device 51 is in the neutral state, the boom connecting pin 144a is in the on state (the state shown in FIG. 2D ). When the first detecting device 51 is in the neutral state, the states of the first sensor 512, the second sensor 513, and the third sensor 514 are as described above.

[0182] In this way, the first detection device 51 detects that the boom connecting pin 144a has reached the neutral state when the output of the first sensor 512 is ON, the output of the second sensor 513 is ON, and the output of the third sensor 514 is OFF.

[0183] Furthermore, when the second detection device 52 is transitioning from the second state toward the neutral state, the output of the sensor 521 changes from the second voltage toward the neutral voltage in accordance with the phase of the object to be detected 520. When the output of the sensor 521 is changing from the second voltage toward the neutral voltage, the second detection device 52 detects that the boom connecting pin 144a is transitioning from the uncoupled state to the coupled state.

[0184] When the boom connecting pin 144a enters the closed state, the second detecting device 52 enters the neutral state. When the second detecting device 52 enters the neutral state, the output of the sensor 521 becomes a neutral voltage. When the output of the sensor 521 becomes a neutral voltage, the second detecting device 52 detects that the boom connecting pin 144a has entered the closed state.

[0185] In this state, the pair of boom connecting pins 144a engage with the pair of second boom pin receiving portions 142c of the intermediate boom 142, as shown in FIG. 2D.

[0186] In the state shown in FIG. 2D, the states of the members are as follows (see T4 in FIG. 12). Brake mechanism 42: OFF Electric motor 41: OFF Cylinder coupling mechanism 45: extended state Boom linkage 46: extended state Cylinder connecting pins 454A and 454B: in position Boom connecting pin 144a: in position

[0187] 2D, the electric motor 41 is rotated in the reverse direction (in the direction indicated by the arrow A1 in FIG. 10A), causing the cylinder connecting mechanism 45 to displace the pair of cylinder connecting pins 454A, 454B in a direction in which they separate from the pair of cylinder pin receiving portions 141a of the tip boom 141. At this time, the cylinder connecting mechanism 45 transitions from the extended state to the retracted state.

[0188] When the state transitions from FIG. 2D to FIG. 2E, the states of the components are as follows (see T5 to T6 in FIG. 12). Brake mechanism 42: OFF Electric motor 41: ON (reverse) Cylinder coupling mechanism 45: Expanded state → Contracted state Boom linkage 46: extended state Cylinder connecting pins 454A, 454B: inserted state → removed state Boom connecting pin 144a: in position

[0189] When the pair of cylinder connecting pins 454A, 454B are transitioning from an engaged state to an unengaged state, the first detecting device 51 and the second detecting device 52 of the position information detecting device 5 transition from the neutral state to the first state in response to the rotation of the lower transmission shaft 432b, as shown in FIG. 13.

[0190] When the first detection device 51 is transitioning from the neutral state to the first state, the first sensor 512 faces the first flat surface 510b of the first detection object 510. Therefore, the output of the first sensor 512 is OFF. On the other hand, the second sensor 513 faces the first cylindrical surface 510a of the first detection object 510. Therefore, the output of the second sensor 513 is ON.

[0191] Furthermore, when the first detection device 51 is transitioning from the neutral state to the first state, the third sensor 514 faces the second flat surface 511b of the second detection object 511. Therefore, the output of the third sensor 514 is OFF.

[0192] In this way, the first detection device 51 detects that the pair of cylinder connecting pins 454A, 454B are transitioning from the engaged state to the disengaged state when the output of the first sensor 512 is OFF, the output of the second sensor 513 is ON, and the output of the third sensor 514 is OFF.

[0193] When the pair of cylinder connecting pins 454A, 454B enter the withdrawn state, the first detecting device 51 enters the first state. In other words, when the first detecting device 51 enters the first state, the pair of cylinder connecting pins 454A, 454B enters the withdrawn state (the state shown in FIG. 2E).

[0194] In the first state of the first detection device 51, the first sensor 512 faces the first flat surface 510b of the first detection object 510. Therefore, the output of the first sensor 512 is OFF. On the other hand, in the first state of the first detection device 51, the second sensor 513 faces the first cylindrical surface 510a of the first detection object 510. Therefore, the output of the second sensor 513 is ON.

[0195] Furthermore, in the first state of the first detection device 51, the third sensor 514 faces the second cylindrical surface 511a of the second detection object 511. Therefore, the output of the third sensor 514 is ON.

[0196] In this way, the first detection device 51 detects that the pair of cylinder connecting pins 454A, 454B have entered the removed state when the output of the first sensor 512 is OFF, the output of the second sensor 513 is ON, and the output of the third sensor 514 is ON.

[0197] When the second detection device 52 is transitioning from the neutral state to the first state, the output of the sensor 521 changes depending on the phase of the object to be detected 520. Here, the sensor 521 is configured to output a predetermined voltage (hereinafter referred to as a first voltage) corresponding to the first state.

[0198] Therefore, when the second detection device 52 is transitioning from the neutral state to the first state, the output of the sensor 521 changes from the neutral voltage to the first voltage. When the output of the sensor 521 changes from the neutral voltage to the first voltage, the second detection device 52 detects that the pair of cylinder connecting pins 454A, 454B is transitioning from the engaged state to the disengaged state.

[0199] When the pair of cylinder connecting pins 454A, 454B enters the uncoupled state, the second detection device 52 enters the first state. In the first state of the second detection device 52, the output of the sensor 521 becomes a first voltage. When the output of the sensor 521 becomes the first voltage, the second detection device 52 detects that the pair of cylinder connecting pins 454A, 454B enters the uncoupled state.

[0200] 2E, when the cylinder connecting pins 454A, 454B are in the disengaged state, the engagement between the tip ends of the pair of cylinder connecting pins 454A, 454B and the pair of cylinder pin receivers 141a of the tip boom 141 is released. When the first detection device 51 and / or the second detection device 52 detects that the pair of cylinder connecting pins 454A, 454B are in the disengaged state, the control unit turns on the brake mechanism 42 and turns off the electric motor 41, thereby stopping the operation of the cylinder connecting mechanism 45.

[0201] In the state shown in FIG. 2E, the states of the members are as follows (see T6 in FIG. 12). Brake mechanism 42: ON Electric motor 41: OFF Cylinder coupling mechanism 45: Retracted state Boom linkage 46: extended state Cylinder connecting pins 454A and 454B: Removed Boom connecting pin 144a: in position

[0202] In the first state (see FIG. 13) of the first detecting device 51 and the second detecting device 52, the cylinder connecting pins 454A, 454B are in the withdrawn state, and the boom connecting pin 144a is in the engaged state. This combination of states is the third set of combinations of the states of the cylinder connecting pins and the boom connecting pins.

[0203] Thereafter, although not shown, when pressure oil is supplied to the retraction-side hydraulic chamber of the telescopic cylinder 3 of the actuator 2, the cylinder member 32 is displaced in the retraction direction (to the right in FIG. 2). At this time, since the tip boom 141 and the cylinder member 32 are not connected, the cylinder member 32 is displaced independently in the retraction direction. When the intermediate boom 142 is extended, the operations shown in FIGS. 2A to 2E are performed on the intermediate boom 142.

[0204] Next, we will explain the abnormality detection control executed by the computer (control unit 530) mounted on the mobile crane 1 of this embodiment. Hereinafter, the control of the extension and retraction operation of the telescopic boom 14 executed by the control unit 530 will be referred to as extension and retraction operation control. The abnormality detection control is basically executed in the extension and retraction operation control.

[0205] The abnormality detection control includes a process in which the control unit 530 detects that an abnormality has occurred in the main detection device (second detection device 52) and the sub detection device (first detection device 51) based on the detection results of the main detection device (second detection device 52) and the sub detection device (first detection device 51). The abnormality detection control also includes a process in which the control unit 530 identifies the detection device in which the abnormality has occurred (hereinafter referred to as the abnormality detection device) based on the detection results of the main detection device (second detection device 52) and the sub detection device (first detection device 51).

[0206] Fig. 14 is a flowchart showing an example of abnormality detection control. The order of control processes in the abnormality detection control is not limited to the order shown in the flowchart in Fig. 14. The control processes shown in the flowchart in Fig. 14 may be performed in any order and at any timing as long as there is no technical contradiction. Unless otherwise specified, the main body of abnormality detection control is the control unit 530.

[0207] First, in step S101 in FIG. 14, control unit 530 starts flag control.

[0208] Here, the flag control will be described. In the flag control, the control unit 530 controls the ON / OFF of a first flag that indicates whether or not the main detection device (second detection device 52) has detected a combination of the states of the cylinder connecting pin and the boom connecting pin.

[0209] In addition, in flag control, the control unit 530 controls ON / OFF of a second flag that indicates whether or not the sub-detecting device (first detecting device 51) has detected a combination of the states of the cylinder connecting pin and the boom connecting pin.

[0210] The combinations of the states of the cylinder connecting pin and the boom connecting pin include a first set (corresponding to combination No. 3 in FIG. 15) in which the cylinder connecting pin is in the engaged state and the boom connecting pin is in the engaged state, a second set (corresponding to combination No. 5 in FIG. 15) in which the cylinder connecting pin is in the engaged state and the boom connecting pin is in the disengaged state, and a third set (corresponding to combination No. 1 in FIG. 15) in which the cylinder connecting pin is in the disengaged state and the boom connecting pin is in. Hereinafter, the sets constituting the combinations of the states of the cylinder connecting pin and the boom connecting pin will be simply referred to as the first set, the second set, and the third set.

[0211] The first flag is made up of a flag element corresponding to the first set (corresponding to check flag No. 3 in FIG. 15), a flag element corresponding to the second set (corresponding to check flag No. 5 in FIG. 15), and a flag element corresponding to the third set (corresponding to check flag No. 1 in FIG. 15). Each flag element of the first flag corresponds to an example of the first flag element.

[0212] During the telescopic operation control or the self-check control described below, when the cylinder connecting pin is in the engaged state and the boom connecting pin is in the engaged state, and the second detection device 52 detects that the cylinder connecting pin is in the engaged state and the boom connecting pin is in the engaged state, the control unit 530 turns ON the flag element corresponding to the first set in the first flag.

[0213] Furthermore, during telescopic operation control or self-check control described below, if the cylinder connecting pin is in the engaged state and the boom connecting pin is in the disengaged state, and the second detection device 52 detects that the cylinder connecting pin is in the engaged state and the boom connecting pin is in the disengaged state, the control unit 530 turns ON the flag element corresponding to the second set in the first flag.

[0214] Furthermore, during telescopic operation control or self-check control described below, if the cylinder connecting pin is in the removed state and the boom connecting pin is in the inserted state, and the second detection device 52 detects that the cylinder connecting pin is in the removed state and the boom connecting pin is in the inserted state, the control unit 530 turns ON the flag element corresponding to the third set in the first flag.

[0215] The second flag is made up of a flag element corresponding to the first set (corresponding to check flag No. 3 in FIG. 15), a flag element corresponding to the second set (corresponding to check flag No. 5 in FIG. 15), and a flag element corresponding to the third set (corresponding to check flag No. 1 in FIG. 15). Each flag element of the second flag corresponds to an example of the second flag element.

[0216] During the telescopic operation control or the self-check control described below, when the cylinder connecting pin is in the engaged state and the boom connecting pin is in the engaged state, and the first detection device 51 detects that the cylinder connecting pin is in the engaged state and the boom connecting pin is in the engaged state, the control unit 530 turns ON the flag element corresponding to the first set in the second flag.

[0217] Furthermore, in the telescopic operation control or the self-check control described below, if the cylinder connecting pin is in the engaged state and the boom connecting pin is in the disengaged state, and the first detection device 51 detects that the cylinder connecting pin is in the engaged state and the boom connecting pin is in the disengaged state, the control unit 530 turns ON the flag element corresponding to the second set in the second flag.

[0218] During the telescopic operation control or the self-check control described below, if the cylinder connecting pin is in the removed state and the boom connecting pin is in the inserted state, and the first detection device 51 detects that the cylinder connecting pin is in the removed state and the boom connecting pin is in the inserted state, the control unit 530 turns ON the flag element corresponding to the third set in the second flag.

[0219] When all the flag elements of the first flag are ON, the control unit 530 performs flag check control, which will be described later, and then resets (turns OFF) all the flag elements of the first flag, and then repeats the flag control.

[0220] Furthermore, when all flag elements of the second flag are ON, the control unit 530 performs flag check control, which will be described later, and then resets (turns OFF) all flag elements of the second flag, and then repeats the flag control.

[0221] The ON / OFF control of the first flag and the second flag in the telescopic operation control or the self-check control described below is flag control. Note that the control unit 530 may cause the display unit to display, at an appropriate timing, an image showing the state (which may be the state of the first flag) of the cylinder connecting pin and the boom connecting pin corresponding to the detection result of the main detection device (second detection device 52) and an image showing the state (which may be the state of the second flag) of the cylinder connecting pin and the boom connecting pin corresponding to the detection result of the sub detection device (first detection device 51).

[0222] Next, in step S102, the control unit 530 determines whether the main detection device (second detection device 52) is normal or not.

[0223] The control unit 530 determines whether the output (voltage value in this embodiment) of the main detection device (second detection device 52) is within a normal range (see FIG. 15) during the extension / retraction operation control or the self-check control described below. The range of the output of the main detection device (second detection device 52) in a normal state corresponds to an example of a first predetermined condition.

[0224] The control unit 530 determines that the main detector (second detector 52) is normal when the output of the main detector (second detector 52) is within the normal range. On the other hand, the control unit 530 determines that the second detector 52 is abnormal when the output of the main detector (second detector 52) is outside the normal range.

[0225] If it is determined in step S102 that the main detector (second detector 52) is normal, the control unit 530 advances the control process to step S103. On the other hand, if it is determined in step S102 that the main detector (second detector 52) is not normal, the control unit 530 advances the control process to step S104.

[0226] Next, a control process after it is determined in step S102 that the main detector (second detector 52) is not normal will be described.

[0227] In step S104, the control unit 530 determines whether the sub-detector (first detector 51) is normal.

[0228] A first example of a method for determining whether the sub-detector (first detector 51) is normal or not will be described. The first example of the method is performed when the control process transitions from step S102 to step S104.

[0229] The control unit 530 determines whether the combination of outputs from the sub-detector (first detector 51) is a normal combination (see FIG. 15) during the extension / retraction operation control or the self-check control described below. The combination corresponds to an example of the second predetermined condition. The appropriate combination is the combination of outputs (ON / OFF) from the first sensor 512, second sensor 513, and third sensor 514 of the sub-detector (first detector 51) in FIG. 15.

[0230] The control unit 530 determines that the sub-detector (first detector 51) is normal when the combination of outputs from the sub-detector (first detector 51) is normal. On the other hand, the control unit 530 determines that the sub-detector (first detector 51) is abnormal when the combination of outputs from the sub-detector (first detector 51) is not normal.

[0231] Next, a second example of a method for determining whether the sub-detector (first detector 51) is normal will be described. The second example of the method is performed when the control process transitions from step S112 to step S104, which will be described later.

[0232] In the second example of the determination method, the control unit 530 determines whether the sub-detector (first detector 51) is normal based on the results of the self-check control performed in step S111, which will be described later. Note that depending on the circumstances under which the abnormality occurs, there are cases in which the occurrence of an abnormality in the sub-detector (first detector 51) cannot be detected by the self-check control. However, the device in which the abnormality occurred can be identified by the flag check control, which will be described later.

[0233] If it is determined in step S104 that the sub-detector (first detector 51) is normal, the control unit 530 advances the control process to step S105. On the other hand, if it is determined in step S104 of FIG. 14 that the sub-detector (first detector 51) is not normal, the control unit 530 advances the control process to step S106.

[0234] In step S105, control unit 530 issues a warning. The warning includes information indicating that an abnormality has occurred in the main detection device (second detection device 52). The warning may be issued by displaying on the display unit or by emitting a warning sound. Thereafter, control unit 530 advances the control process to step S107.

[0235] In step S107, the control unit 530 switches the detection device used for controlling the extension and retraction operation from the main detection device (second detection device 52) to the sub detection device (first detection device 51). Then, the control unit 530 advances the control process to step S108.

[0236] In step S108, the control unit 530 continues the extension / contraction operation control based on the detection result of the sub-detector (first detector 51). Note that the control unit 530 may end the extension / contraction operation control at an appropriate timing.

[0237] After determining in step S104 that the sub-detector (first detector 51) is not normal, the control unit 530 stops the extension and retraction operation of the telescopic boom 14 in step S106. Then, the control unit 530 ends the extension and retraction operation control and the abnormality detection control.

[0238] Next, in step S102, after determining that the main detection device (second detection device 52) is normal, in step S103, the control unit 530 determines whether the sub detection device (first detection device 51) is normal. The determination method performed by the control unit 530 in step S103 is the same as the first example determination method performed by the control unit 530 in step S104.

[0239] In step S103, if the sub-detector (first detector 51) is normal, the control unit 530 advances the control process to step S109. On the other hand, in step S103, if the sub-detector (first detector 51) is not normal, the control unit 530 advances the control process to step S110.

[0240] In step S110, the control unit 530 issues a warning. The warning includes information indicating that an abnormality has occurred in the sub-detector. The warning may be issued by displaying a message on the display unit or by emitting a warning sound. The control unit 530 then advances the control process to step S109. The reason for advancing the control process to step S109 is that the main detector (second detector 52) is normal, and therefore the control unit 530 can start or continue control of the extension / retraction operation based on the detection result of the main detector (second detector 52).

[0241] Next, in step S109, the control unit 530 starts the extension / retraction operation control based on the detection result of the main detection device (second detection device 52). If the extension / retraction operation control based on the detection result of the main detection device (second detection device 52) has already started, the control unit 530 continues the extension / retraction operation control based on the detection result of the main detection device (second detection device 52). Then, the control unit 530 advances the control process to step S111.

[0242] Next, in step S111 of FIG. 14, control unit 530 performs self-check control.

[0243] Here, the self-check control will be explained. The self-check control is a control that is performed by the control unit 530 when the telescopic boom 14 falls into a predetermined situation.

[0244] Specifically, the above-mentioned predetermined situation refers to an unloaded situation in which no load from the boom elements is acting on the boom connecting pin. The above-mentioned predetermined situation can also refer to a fully retracted telescopic cylinder situation in which the telescopic cylinder 3 is in a fully retracted state. In the unloaded situation and the fully retracted cylinder situation, the load from the boom elements is not acting on the cylinder connecting pin and the boom connecting pin, so the cylinder connecting pin and the boom connecting pin can move stably. The unloaded situation and the fully retracted cylinder situation can occur both before and after the telescopic boom starts to extend or retract. The above-mentioned predetermined situation is not limited to the above example, and the control unit may also perform self-check control at an appropriate timing.

[0245] In the self-check control, the control unit 530 transitions at least the boom connecting pin from the engaged state to the disengaged state, or from the disengaged state to the engaged state. Note that in the self-check control, the control unit 530 may transition the cylinder connecting pin from the engaged state to the disengaged state, or from the disengaged state to the engaged state.

[0246] By carrying out the self-check control, the flag control can be carried out in the above-mentioned predetermined situation without extending or retracting the telescopic boom 14.

[0247] In the self-check control, the control unit 530 preferably controls the states of the cylinder connecting pin and the boom connecting pin so that all flag elements of the first flag and the second flag are ON. However, the control unit 530 may control the cylinder connecting pin and the boom connecting pin so that only some flag elements of the first flag and the second flag are ON depending on the state of the telescopic boom 14.

[0248] The control unit 530 can determine whether or not an abnormality has occurred in the main detection device (second detection device 52) and the sub-detector device (first detection device 51) by comparing the combination of the states of the cylinder connecting pin and the boom connecting pin realized by self-check control with the states of the first flag and the second flag. Furthermore, if an abnormality has occurred in the main detection device (second detection device 52) and / or the sub-detector device (first detection device 51), the control unit 530 can identify the detection device in which the abnormality has occurred based on the result of the above-mentioned comparison.

[0249] A specific example of the self-check control will be described below with reference to Fig. 2A and Fig. 15. The state of the telescopic boom 14 shown in Fig. 2A is a no-load state where no load from the boom element is acting on the boom connecting pin, and also a fully retracted state where the telescopic cylinder 3 is fully retracted. Therefore, the state of the telescopic boom 14 shown in Fig. 2A corresponds to the above-mentioned predetermined state.

[0250] 2A, the cylinder connecting pin is in the engaged state, and the boom connecting pin (specifically, boom connecting pin 144a) is in the engaged state. In this state, if the main detection device (second detection device 52) and the sub detection device (first detection device 51) are operating normally, the flag element corresponding to the first set in the first flag is turned ON by the above-described flag control, and the flag element corresponding to the first set in the second flag is turned ON.

[0251] Next, the control unit 530 transitions the boom connecting pin (specifically, the boom connecting pin 144a) from the engaged state to the disengaged state through self-check control. In this state, the cylinder connecting pin is in the engaged state, and the boom connecting pin (specifically, the boom connecting pin 144a) is in the disengaged state. Therefore, if the main detection device (second detection device 52) and the sub-detection device (first detection device 51) are operating normally, the flag element corresponding to the second set in the first flag is turned ON through the above-mentioned flag control, and the flag element corresponding to the second set in the second flag is turned ON. Thereafter, the boom connecting pin (specifically, the boom connecting pin 144a) is transitioned from the disengaged state to the engaged state, returning to the state shown in FIG. 2A.

[0252] If the main detector (second detector 52) and the sub detector (first detector 51) are operating normally through the self-check control described above, the states of the first flag and the second flag will be as follows:

[0253] [Normal state of the first and second flags] Flag element corresponding to the first group in the first flag: ON Flag element corresponding to the first group in the second flag: ON Flag element corresponding to the second group in the first flag: ON Flag element corresponding to the second set in the second flag: ON

[0254] However, when the main detector (second detector 52) or the sub detector (first detector 51) is not operating normally (i.e., when an abnormality occurs), the states of the first flag and the second flag differ from the normal states of the first flag and the second flag described above. As a result, the control unit 530 can detect that an abnormality has occurred in the main detector (second detector 52) or the sub detector (first detector 51). Furthermore, the control unit 530 can identify a detector whose flag states differ from the normal states of the first flag and the second flag described above as a detector in which an abnormality has occurred.

[0255] In the above example, the states of the flags corresponding to the first and second sets are known, but the state of the flag corresponding to the third set (cylinder connecting pin removed and boom connecting pin inserted) is unknown. Therefore, depending on the circumstances under which the abnormality occurs, there may be cases where it is not possible to detect that an abnormality has occurred in the detection device.

[0256] Therefore, in addition to the above-described self-check control, the states of the flag elements corresponding to the third set in the first flag and the flag elements corresponding to the third set in the second flag can be checked by transitioning the cylinder connecting pin from the engaged state to the disengaged state in the state shown in Fig. 2A. By adding such control, it is possible to detect that an abnormality has occurred in a detection device and to identify the detection device in which the abnormality has occurred, regardless of the circumstances under which the abnormality has occurred.

[0257] By performing the self-check control as described above, it is possible to quickly and stably detect an abnormality in the detection device. After performing the self-check control, control unit 530 advances the control process to step S112.

[0258] In step S112 of FIG. 14, the control unit 530 determines whether the main detection device (second detection device 52) is normal or not based on the result of the self-check described above.

[0259] If it is determined in step S112 that the main detector (second detector 52) is normal, the control unit 530 advances the control process to step S113. On the other hand, if it is determined in step S112 that the main detector (second detector 52) is not normal, the control unit 530 advances the control process to step S104. Note that the control process in step S104 when the process proceeds from step S112 to step S104 is as described above.

[0260] Next, in step S113, the control unit 530 determines whether the sub-detector (first detector 51) is normal based on the result of the self-check control performed in step S111. As described above, depending on the circumstances under which the abnormality occurs, there are cases in which it is not possible to detect that an abnormality has occurred in the sub-detector (first detector 51). However, even in cases in which the self-check control cannot detect that an abnormality has occurred, it is possible to detect that an abnormality has occurred by using the flag check control described below.

[0261] If it is determined in step S113 that the sub-detector (first detector 51) is normal, the control unit 530 advances the control process to step S114. On the other hand, if it is determined in step S113 that the sub-detector (first detector 51) is not normal, the control unit 530 advances the control process to step S115.

[0262] In step S115, the control unit 530 issues a warning. The warning includes information indicating that an abnormality has occurred in the sub-detector (first detector 51). The warning may be issued by displaying on the display unit or by emitting a warning sound. Thereafter, the control unit 530 advances the control process to step S114. The reason for advancing the control process to step S114 is that the main detector (second detector 52) is normal, and therefore the control unit 530 can continue to control the extension / retraction operation based on the detection result of the main detector (second detector 52).

[0263] Next, in step S114, the control unit 530 determines whether or not the detection result of the main detector (second detector 52) and the detection result of the sub detector (first detector 51) match.

[0264] If the detection result of the main detector (second detector 52) and the detection result of the sub detector (first detector 51) do not match, the control unit 530 determines that an abnormality has occurred in at least one of the main detector (second detector 52) and the sub detector (first detector 51). Then, the control unit 530 advances the control process to step S117.

[0265] On the other hand, if the detection result of the main detector (second detector 52) and the detection result of the sub detector (first detector 51) match, the control unit 530 determines that no abnormality has occurred in the main detector (second detector 52) and the sub detector (first detector 51) (they are normal). Then, the control unit 530 advances the control process to step S116.

[0266] In step S117, the control unit 530 issues a warning. The warning includes information indicating that an abnormality has occurred in at least one of the main detection device (second detection device 52) and the sub detection device (first detection device 51). The warning may be issued by displaying on the display unit or by emitting a warning sound. The control unit 530 then advances the control process to step S116. The reason for advancing the control process to step S116 is to identify the detection device in which the abnormality has occurred by flag check control, which will be described later.

[0267] In step S116, control unit 530 determines whether or not the situation corresponds to one in which flag check control can be performed.

[0268] When all flag elements of at least one of the first flag and the second flag are ON, control unit 530 determines that the situation corresponds to a situation in which flag check control can be performed. Then, control unit 530 proceeds to step S118. Note that the control processes from step S116 onward may be performed at appropriate timing.

[0269] On the other hand, if there is no flag in which all flag elements are ON in the first flag and the second flag, control unit 530 determines that the situation does not correspond to a situation in which flag check control can be performed. Then, control unit 530 proceeds to control processing at step S108. The operation of control unit 530 at step S108 is as described above.

[0270] In step S118, control unit 530 performs flag check control. In the flag check control, control unit 530 compares the flag elements of the first flag with the flag elements of the second flag. Then, control unit 530 proceeds to step S119.

[0271] In step S119, control unit 530 determines whether or not the flag elements of the first flag and the flag elements of the second flag match.

[0272] If the flag elements of the first flag and the flag elements of the second flag match, the control unit 530 ends the control process and then repeats the abnormality detection control from step S102. Since it is determined in step S116 that the flag elements of at least one of the first flag and the second flag are all ON, the fact that the flag elements of the first flag and the flag elements of the second flag match means that the flag elements of the first flag and the second flag are all ON. This means that the main detection device (second detection device 52) and the sub detection device (first detection device 51) can normally detect the combination of the states of the cylinder connecting pin and the boom connecting pin.

[0273] On the other hand, if the flag elements of the first flag and the flag elements of the second flag do not match, the control unit 530 proceeds to step S120. Since it was determined in step S116 that all of the flag elements of at least one of the first flag and the second flag are ON, the fact that the flag elements of the first flag and the flag elements of the second flag do not match means that all of the flag elements of the other of the first flag and the second flag are not ON (i.e., the flag elements of the other flag include OFF). This means that the other detection device described above is unable to detect the combination of the states of the cylinder connecting pin and the boom connecting pin. In other words, this means that an abnormality has occurred in the other detection device described above.

[0274] In step S120, the control unit 530 identifies the abnormality detection device, which is the detection device in which the abnormality has occurred. Specifically, first, from the first flag and the second flag, flags in which all flag elements are not ON (i.e., flags in which flag elements include OFF) are identified. Then, the abnormality detection device is identified based on the identified flags.

[0275] For example, if not all flag elements of the first flag are ON, the control unit 530 identifies the main detection device (second detection device 52) as the abnormality detection device. On the other hand, if not all flag elements of the second flag are ON, the control unit 530 identifies the sub detection device (first detection device 51) as the abnormality detection device. Then, the control unit 530 proceeds to step S121.

[0276] In step S121, control unit 530 issues a warning. The warning includes information indicating the abnormality detection device. The warning may be issued by displaying on the display unit or by emitting a warning sound. Thereafter, control unit 530 ends the control process.

[0277] After step S121, if the abnormality detection device is the main detection device (second detection device 52), the control unit 530 may switch the detection device used for extension / retraction operation control from the main detection device (second detection device 52) to the sub detection device (first detection device 51), and continue extension / retraction operation control. In this case, since the abnormality detection device has been identified, the control unit 530 may continue or stop the above-mentioned abnormality detection control. If the abnormality detection control is to be continued, the control unit 530 repeats the abnormality detection control from step S102.

[0278] Furthermore, after step S121, if the abnormality detection device is a sub-detection device (first detection device 51), the control unit 530 may continue the extension / retraction operation control. In this case, too, since the abnormality detection device has been identified, the control unit 530 may continue or stop the abnormality detection control described above. If the abnormality detection control is to be continued, the control unit 530 repeats the abnormality detection control from step S102.

[0279] <Actions and Effects of This Embodiment> In the case of the mobile crane 1 of this embodiment having the above-described configuration, the positions of the pair of cylinder connecting pins 454A, 454B and the boom connecting pins 144a, 144b are detected by the above-described position information detecting device 5. Therefore, the extension and retraction operation of the telescopic boom 14 can be controlled with high precision.

[0280] In particular, in the present embodiment, the position information detecting device 5 has a first detecting device 51 and a second detecting device 52 which have different detection methods. Under normal circumstances, the second detecting device 52 detects information related to the position, and if the second detecting device 52 fails, the first detecting device 51 detects information related to the position. Therefore, even if either the first detecting device 51 or the second detecting device 52 fails, the positions of the pair of cylinder connecting pins 454A, 454B and the boom connecting pins 144a, 144b can be detected.

[0281] Furthermore, during normal control, the control unit 530 can determine whether the detection devices have failed based on the detection values ​​of the first detection device 51 and the second detection device 52, while detecting information relating to the positions of the pair of cylinder connecting pins 454A, 454B and the pair of boom connecting pins 144a, 144b based on the detection value of the second detection device 52. As a result, the control unit 530 can quickly detect that a failure has occurred in at least one of the detection devices, the first detection device 51 and the second detection device 52.

[0282] Furthermore, in this embodiment, since the first detector 51 and the second detector 52 have different detection methods, it is possible to prevent both detectors from being simultaneously affected by noise. If the first detector 51 and the second detector 52 had the same detection method, there is a possibility that the first detector 51 and the second detector 52 would be simultaneously affected by noise. On the other hand, in this embodiment, since the detection method of the first detector 51 and the detection method of the second detector 52 are different, even if one detector is affected by noise, the other detector is less likely to be affected by the same noise. As a result, in this embodiment, it is possible to prevent a state in which the first detector 51 and the second detector 52 are unable to simultaneously detect the positions of the pair of cylinder connecting pins 454A, 454B and the boom connecting pins 144a, 144b due to the influence of noise (a state in which detection accuracy is low).

[0283] Furthermore, in the case of this embodiment, the occurrence of an abnormality in the main detector (second detector 52) and the sub detector (first detector 51) can be detected by the abnormality detection control described above. In particular, in the case of this embodiment, the detection device in which the abnormality has occurred can also be identified by the self-check control or flag check control described above. As a result, the extension / retraction operation control can be performed more safely.

[0284] <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]

[0285] The present invention is not limited to cranes, but can be applied to various work machines equipped with telescopic booms (for example, aerial work platforms). [Explanation of symbols]

[0286] 1. Mobile crane 10 Running body 12 Swivel table 14 Telescopic Boom 141 Tip boom 141a Cylinder pin receiving part 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 143 Base boom 144a, 144b Boom connecting pin 144c Pin side receiving part 16 Wire Rope 17 Hook 2 Actuators 3 Telescopic cylinder 31 Rod member 32 Cylinder parts 4 Pin moving mechanism 40 Trunnion 400 Fixed part 401 Support hole 41 Electric motor 410 Cover 42 Brake mechanism 43 Transmission Mechanism 431 Reducer 432 Vertical transmission mechanism 432a Upper transmission shaft 432b Lower transmission shaft 45 Cylinder connection mechanism 450 Switchgear 451 First Rack Bar 452 First Gear Mechanism 453 Second Gear Mechanism 454A, 454B Cylinder connecting pin 455 First biasing mechanism 455a, 455b Coil spring 46 Boom connection mechanism 461a, 461b Second rack bar 461c Drive rack teeth 461g, 461h Locking claw part 462 Synchronous Gear 463 Second biasing mechanism 463a, 463b Coil spring 5. Location information detection device 50 Support 501 Right side plate 502 Left side plate 503 Rear side plate 504 Right side fixing plate 505 Left side fixing plate 506 Containment Space 507 Locating Pin 51 First detection device 510 First detection object 510a First cylindrical surface 510b First flat surface 511 Second detection object 511a Second cylindrical surface 511b Second flat surface 512 First Sensor 513 Second Sensor 514 Third Sensor 52 Second detection device 520 Object to be detected 521 Sensors 530 Control Unit 54 Cover member

Claims

1. A plurality of booms that are extended and retracted by telescopic cylinders; a first pin that can transition between an engaged state in which the boom and the telescopic cylinder are connected and an uncoupled state in which the connection is released; a second pin that can transition between an on-state in which adjacent booms are connected and an off-state in which the connection is released; a main detection device and a sub-detection device capable of detecting a combination of states of the first pin and the second pin; a control unit that controls the extension and contraction operation of the boom based on the detection result of the main detection device, The combination of the states of the first pin and the second pin is a first set in which the first pin is in an engaged state and the second pin is in an engaged state; a second set in which the first pin is in an engaged state and the second pin is in an unengaged state; a third set in which the first pin is in a withdrawn state and the second pin is in a engaged state, The control unit, during the extension and retraction operation of the boom, controlling ON / OFF of a first flag indicating whether the main detection device has detected the combination, the first flag being composed of three first flag elements corresponding to the first set, the second set, and the third set, and controlling ON / OFF of a second flag indicating whether the sub detection device has detected the combination, the second flag being composed of three second flag elements corresponding to the first set, the second set, and the third set; detecting that an abnormality has occurred in the main detection device and the sub detection device based on the first flag and the second flag; When all flag elements of one of the first flag and the second flag are ON, comparing the first flag with the second flag to identify an abnormality detection device in which an abnormality has occurred, from among the main detection device and the sub detection device; Work equipment.

2. A plurality of booms that are extended and retracted by telescopic cylinders; a first pin that can transition between an engaged state in which the boom and the telescopic cylinder are connected and an uncoupled state in which the connection is released; a second pin that can transition between an on-state in which adjacent booms are connected and an off-state in which the connection is released; a main detection device and a sub-detection device capable of detecting a combination of states of the first pin and the second pin; a control unit that controls the extension and contraction operation of the boom based on the detection result of the main detection device, The control unit, during the extension and retraction operation of the boom, controlling ON / OFF of a first flag indicating whether the main detection device has detected the combination and ON / OFF of a second flag indicating whether the sub detection device has detected the combination; detecting that an abnormality has occurred in the main detection device and the sub detection device based on the first flag and the second flag; comparing the first flag with the second flag to identify an abnormality detection device in which an abnormality has occurred, from among the main detection device and the sub detection device; The control unit performing self-check control to transition the state of the first pin and / or the second pin without extending or contracting the boom under a predetermined condition; During the self-check control, the first flag and the second flag are controlled to be turned on and off; Identifying the abnormality detection device based on the first flag and the second flag. Work equipment.

3. A plurality of booms that are extended and retracted by telescopic cylinders; a first pin that can transition between an engaged state in which the boom and the telescopic cylinder are connected and an uncoupled state in which the connection is released; a second pin that can transition between an on-state in which adjacent booms are connected and an off-state in which the connection is released; a main detection device and a sub-detection device capable of detecting a combination of states of the first pin and the second pin; a control unit that controls the extension and contraction operation of the boom based on the detection result of the main detection device, the main detector and the sub detector detect the combination using different detection methods; The control unit, during the extension and retraction operation of the boom, controlling ON / OFF of a first flag indicating whether the main detection device has detected the combination and ON / OFF of a second flag indicating whether the sub detection device has detected the combination; detecting that an abnormality has occurred in the main detection device and the sub detection device based on the first flag and the second flag; Work equipment.

4. The control unit In the comparison, If the other of the first flag and the second flag is also all ON, it is determined that the abnormality has not occurred, If all of the other flags are not ON, it is determined that an abnormality has occurred in the detection device corresponding to the other flag. The work machine according to claim 1 .

5. 3. The work implement according to claim 2, wherein the predetermined state includes a no-load state in which no load of the boom is acting on the second pin, or a fully retracted state in which the telescopic cylinder is fully retracted.

6. The control unit When the output of the main detector does not satisfy a first predetermined condition, it is detected that an abnormality has occurred in the main detector; When the output of the sub-detection device does not satisfy a second predetermined condition, it is detected that an abnormality has occurred in the sub-detection device; When an abnormality occurs in the main detection device but an abnormality does not occur in the sub detection device, the extension and contraction operation of the boom is controlled based on the detection result of the sub detection device; When an abnormality occurs in the main detection device and the sub detection device, control of the extension and contraction operation of the boom is stopped. A work machine according to any one of claims 1 to 3.

7. A work machine described in any one of claims 1 to 3, wherein the control unit detects that an abnormality has occurred in either the main detection device or the sub-detection device when the detection result of the main detection device and the detection result of the sub-detection device do not match.

8. the main detection device is configured with a potentiometer and detects the combination based on a voltage value that is an output of the potentiometer; The work machine according to any one of claims 1 to 3, wherein the sub-detection device is configured by a plurality of proximity sensors and detects the combination based on a combination of detection values ​​of the plurality of proximity sensors.

9. The work machine according to any one of claims 1 to 3, wherein the control unit causes a display unit to display an image showing the state of the first pin and the second pin corresponding to the detection result of the main detection device, and an image showing the state of the first pin and the second pin corresponding to the detection result of the sub detection device.

Images