Work equipment

Abstract

To provide a work machine capable of increasing work efficiency.SOLUTION: The work machine comprises: a plurality of booms elongated / contracted by power of an actuator; a first pin moved by a first spring to connect adjacent booms and moved by power of a motor to release the connection; a second pin moved by a second spring to connect the booms and the actuator and moved by the power of the motor to release the connection; and a circuit configured to set, when the first pin is moved by the first spring or the second pin is moved by the second spring, a state where current based on idling of the motor following the movement of the first pin or the second pin is not generated.SELECTED DRAWING: Figure 6C

Description

[Technical field]

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

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

[0003] A telescopic boom has a boom connecting pin that connects adjacent overlapping booms together. A boom that is released from the connection by the boom connecting pin (hereinafter referred to as a movable boom) becomes movable in the longitudinal direction (also referred to as the telescopic direction) relative to the other booms.

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

[0005] [Patent Document 1] JP 2012-96928 A Summary of the Invention [Problem to be solved by the invention]

[0006] In a crane as described above, if it takes a long time to move the connecting pins, including the boom connecting pin and the cylinder connecting pin, the time required to extend or retract the telescopic boom will be long, which may result in poor work efficiency.

[0007] An object of the present invention is to provide a work machine that can improve work efficiency. [Means for solving the problem]

[0008] One aspect of the working machine according to the present invention is A plurality of booms that are extended and retracted by the power of an actuator; a first pin that moves by a first spring to connect adjacent booms and moves by power of a motor to release the connection; a second pin that moves by a second spring to connect the boom and the actuator and moves by power of the motor to release the connection; and a circuit configured so that, when the first pin is moved by the first spring or the second pin is moved by the second spring, no current is generated due to the idling of the motor accompanying the movement of the first pin or the second pin. Effect of the Invention

[0009] According to the present invention, it is possible to provide a work machine that can improve work efficiency. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a mobile crane according to an embodiment. [Diagram 2] 2A to 2E are schematic diagrams for explaining the structure and telescopic operation of a telescopic boom. [Diagram 3] FIG. 3 is a front view of the pin moving module in the expanded state and holding the boom connecting pin. [Figure 4] FIG. 4 is a front view of the pin moving module with the boom linkage in a retracted position and the cylinder linkage in an extended position. [Diagram 5] FIG. 5 is a front view of the pin moving module with the boom linkage in an extended position and the cylinder linkage in a retracted position. [Figure 6A] FIG. 6A is a circuit diagram of the electric circuit in the first driving state. [Figure 6B] FIG. 6B is a circuit diagram of the electric circuit in the second driving state. [Figure 6C]FIG. 6C is a circuit diagram of the electric circuit in the first open state. [Figure 6D] FIG. 6D is a circuit diagram of the electrical circuit in the second released state. [Figure 6E] FIG. 6E is a schematic diagram of the electrical circuit in the braking state. [Figure 7A] FIG. 7A is a schematic diagram for explaining the operation of the cylinder connecting mechanism. [Figure 7B] FIG. 7B is a schematic diagram for explaining the operation of the cylinder connecting mechanism. [Figure 7C] FIG. 7C is a schematic diagram for explaining the operation of the cylinder connecting mechanism. [Figure 8A] FIG. 8A is a schematic diagram for explaining the operation of the boom connecting mechanism. [Figure 8B] FIG. 8B is a schematic diagram for explaining the operation of the boom connection mechanism. [Figure 8C] FIG. 8C is a schematic diagram for explaining the operation of the boom connection mechanism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. Note that a crane according to the embodiment described below is an example of a work machine according to the present invention, and the present invention is not limited to the embodiment described below.

[0012] [Embodiment] 1 is a schematic diagram of a mobile crane 1 (a rough terrain crane in the illustrated case) according to this embodiment. The mobile crane 1 corresponds to an example of a working machine.

[0013] Examples of the mobile crane include an all-terrain crane, a truck crane, and a loaded truck crane (also called a cargo crane). However, the working machine according to the present invention is not limited to a mobile crane, and may be other working machines (e.g., a crane, aerial work vehicle) equipped with a telescopic boom.

[0014] <Outline of this embodiment> As shown in FIG. 1 and FIGS. 2A to 2E, the mobile crane 1 according to this embodiment has a telescopic boom 14 and an actuator 2 that extends and retracts the telescopic boom 14.

[0015] The telescopic boom 14 has telescopically combined booms (a tip boom 141, a middle boom 142, and a base boom 143). 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 and 454b, and releases the connection between the boom to be moved and the boom adjacent to the boom to be moved by the boom connecting pin. Then, the actuator 2 moves the boom.

[0017] In the telescopic operation of the telescopic boom 14, if the movement time of the boom connecting pins (boom connecting pins 144a, 144b) and cylinder connecting pins 454a, 454b is long, work efficiency may deteriorate. Therefore, the mobile crane 1 according to this embodiment is provided with a function for shortening the movement time of the boom connecting pins (boom connecting pins 144a, 144b) and cylinder connecting pins 454a, 454b in the telescopic operation of the telescopic boom 14. In the case of the mobile crane 1 according to this embodiment, this function is realized by the electric circuit 6 and the control unit 47 described later. The configuration of the mobile crane 1 according to this embodiment will be specifically described below.

[0018] <Mobile crane> As shown in FIG. 1, the mobile crane 1 has a running body 10, outriggers 11, a swivel base 12, a telescopic boom 14, an actuator 2 (omitted from FIG. 1), an electrical circuit 6 (see FIGS. 6A to 6E), a hoisting cylinder 15, a wire rope 16, and a hook 17.

[0019] The traveling body 10 has a plurality of wheels 101. The outriggers 11 are provided at the four corners of the traveling body 10. The swivel base 12 is provided on the upper part of the traveling body 10 so as to be rotatable. The base end of the telescopic boom 14 is fixed to the swivel base 12. The actuator 2 extends and retracts the telescopic boom 14. The hoisting cylinder 15 raises and lowers 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. The hook 17 is provided at the tip of the wire rope 16.

[0020] <Telescopic boom> Next, the telescopic boom 14 will be described with reference to Fig. 1 and Fig. 2A to Fig. 2E. Fig. 2A to Fig. 2E are schematic diagrams for explaining the structure and telescopic operation of the telescopic boom 14.

[0021] The telescopic boom 14 is made up of multiple booms. Each of the multiple booms is cylindrical. The multiple booms are telescopically combined with each other. Specifically, in the contracted state, the multiple booms are, from the inside, a tip boom 141, a middle boom 142, and a base boom 143.

[0022] The tip boom 141 and the intermediate boom 142 are booms that can move in the telescopic direction. The base boom 143 is a boom whose movement in the telescopic direction is restricted.

[0023] The telescopic boom 14 transitions from the contracted state shown in FIG. 2A to the extended state shown in FIG. 1 by extending in sequence starting from the boom disposed on the inside (that is, the tip boom 141).

[0024] In the extended state, the intermediate boom 142 is disposed between the base end boom 143 on the base end side and the tip end boom 141 on the tip end side. There may be multiple intermediate booms.

[0025] The structure of the telescopic boom 14 is almost the same as the structure of conventionally known telescopic booms, but for the sake of convenience in explaining the structure and operation of the actuator 2 described below, the structures of the tip boom 141 and the intermediate boom 142 will be described below.

[0026] <Boom tip> The tip boom 141 is cylindrical and has an internal space capable of accommodating the actuator 2. The tip boom 141 has, at a base end thereof, a pair of cylinder pin receiving portions 141a and a pair of boom pin receiving portions 141b.

[0027] The pair of cylinder pin receiving portions 141a are provided coaxially with each other 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. The pair of cylinder connecting pins 454a, 454b correspond to an example of a second pin.

[0028] The cylinder connecting pins 454a, 454b are each biased in a first direction in the axial direction of the cylinder connecting pins 454a, 454b by a first biasing mechanism 455 described below. The cylinder connecting pins 454a, 454b move in a second direction in their axial direction based on the operation of a cylinder connecting mechanism 45 included in the actuator 2 described below. With the pair of cylinder connecting pins 454a, 454b engaged with the pair of cylinder pin receivers 141a, the tip boom 141 can move together with the cylinder member 32 in the extension / retraction direction.

[0029] The pair of boom pin receiving portions 141b are provided coaxially with each other and closer to the base end than the cylinder pin receiving portion 141a. The boom pin receiving portions 141b are respectively engageable with and disengageable from the pair of boom connecting pins 144a. The pair of boom connecting pins 144a correspond to an example of a first pin.

[0030] Each of the pair of boom connecting pins 144a is biased in a first direction in the axial direction of the boom connecting pins 144a by a second biasing mechanism 463 described later. Each of the pair of boom connecting pins 144a connects the tip boom 141 and the intermediate boom 142 to each other.

[0031] The pair of boom connecting pins 144a move in a second direction in their axial direction based on the operation of the boom connecting mechanism 46 included in the actuator 2. The pair of boom connecting pins 144a may be regarded as components of the boom connecting mechanism 46.

[0032] 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 described below.

[0033] In a state in which the tip boom 141 and the intermediate boom 142 are connected (also referred to as a connected state), the tip boom 141 is prohibited from moving in the extension / contraction direction relative to the intermediate boom 142.

[0034] On the other hand, in a state in which the connection between the tip boom 141 and the intermediate boom 142 is released (also referred to as a non-connected state), the tip boom 141 is capable of moving in the extension / contraction direction relative to the intermediate boom 142.

[0035] <Middle boom> The intermediate boom 142 is cylindrical and has an internal space capable of accommodating the tip boom 141. The intermediate boom 142 has, at a base end thereof, a pair of cylinder pin receiving portions 142a, a pair of first boom pin receiving portions 142b, a pair of second boom pin receiving portions 142c, and a pair of third boom pin receiving portions 142d.

[0036] 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, respectively.

[0037] 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 end boom 143.

[0038] 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.

[0039] <Actuator> 3 to 8C, the actuator 2 will be described below. The actuator 2 is an actuator that extends and retracts the telescopic boom 14.

[0040] The actuator 2 includes a telescopic cylinder 3, a pin moving module 4, and a control unit 47. The actuator 2 is disposed in the internal space of the tip boom 141 when the telescopic boom 14 is in a contracted state (the state shown in FIG. 2A).

[0041] <Telescopic cylinder> The telescopic cylinder 3 has a rod member 31 (also called a fixed member; see Figs. 2A to 2E) and a cylinder member 32 (also called a movable member). The telescopic cylinder 3 moves a boom (for example, the tip boom 141 or the intermediate boom 142) connected to the cylinder member 32 via cylinder connecting pins 454a and 454b (described later) in the telescopic direction.

[0042] <Pin Movement Module> The pin moving module 4 has a housing (not shown), an electric motor 41, a brake mechanism 42, a transmission mechanism 43, a position information detection device 44, a cylinder connecting mechanism 45, and a boom connecting mechanism 46.

[0043] Hereinafter, 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, in describing the actuator 2, a Cartesian coordinate system (X, Y, Z) shown in each drawing will be used. However, the arrangement of each part constituting the actuator 2 is not limited to that of this embodiment. Furthermore, the configuration of the actuator 2 may be omitted as long as it is not technically inconsistent. In other words, the actuator 2 may be configured by a combination of configurations arbitrarily selected from the configurations described below as long as it is not technically inconsistent.

[0044] In the orthogonal coordinate system shown in each figure, the X direction corresponds to the telescopic direction of the telescopic boom 14 when it is mounted on the mobile crane 1. The positive side of the X direction is also referred to as the extension direction in the telescopic direction. The negative side of the X direction is also referred to as the contraction direction in the telescopic direction. The Z direction corresponds to the up-down direction of the mobile crane 1, for example, when the hoisting angle of the telescopic boom 14 is zero (also referred to as the collapsed state of the telescopic boom 14). The Y direction corresponds to the vehicle width direction of the mobile crane 1, for example, when the telescopic boom 14 is facing forward. However, the Y direction and the Z direction are not limited to the above-mentioned directions as long as they are two directions perpendicular to each other.

[0045] <Housing> A housing (not shown) is fixed to the cylinder member 32 of the telescopic cylinder 3. The housing accommodates a cylinder connecting mechanism 45 and a boom connecting mechanism 46, which will be described later, in its internal space. The housing supports an electric motor 41, a brake mechanism 42, and a transmission mechanism 43, which will be described later.

[0046] Such a housing unitizes the above-mentioned elements, and such a configuration contributes to miniaturization of the pin moving module 4, improvement of productivity, and improvement of system reliability.

[0047] The rod member 31 of the telescopic cylinder 3 is inserted in the X direction through a part of the housing. The base end (the end on the - side in the X direction) of the cylinder member 32 of the telescopic cylinder 3 is fixed to the side wall on the + side in the X direction of the housing.

[0048] The housing has first through holes (not shown) on both side walls in the Y direction. A pair of cylinder connecting pins 454a, 454b of the cylinder connecting mechanism 45 are inserted into the first through holes, respectively.

[0049] A transmission shaft 432 (see FIG. 3) of a transmission mechanism 43, which will be described later, is inserted in the X direction through a part of the housing.

[0050] The housing has second through holes (not shown) on both side walls in the Y direction. A pair of second rack bars 461a, 461b of the boom connection mechanism 46 are inserted into the second through holes, respectively.

[0051] <Electric motor> The electric motor 41 is supported by the housing via a reducer 431 of the transmission mechanism 43. Specifically, the electric motor 41 is arranged around the cylinder member 32 (for example, on the positive side in the Z direction) and around the housing (for example, on the negative side in the X direction or the positive side in the Z direction) with the output shaft (not shown) parallel to the X direction. Such an arrangement contributes to the miniaturization of the pin moving module 4 in the Y direction and the Z direction.

[0052] The electric motor 41 as described above is connected to, for example, a power supply device 61 (see FIGS. 6A to 6E) provided on the swivel base 12 via a power supply cable.

[0053] Each of the above-mentioned cables can be reeled out and reeled in by a cord reel provided on the outside of the base end of the telescopic boom 14 or on the swivel base 12 (see FIG. 1).

[0054] The number of electric motors may be one or more (for example, two). In the case where there is one electric motor, as in this embodiment, the cylinder connecting mechanism 45 and the boom connecting mechanism 46 are operated by one electric motor 41. In the case where there are multiple electric motors (for example, two), the cylinder connecting mechanism 45 may be operated by a first electric motor (not shown), and the boom connecting mechanism 46 may be operated by a second electric motor (not shown).

[0055] <Brake mechanism> 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 module 4 when the electric motor 41 is stopped.

[0056] The brake mechanism 42 is connected to, for example, a power supply device (not shown) provided on the swivel base 12 via a power supply cable. The position information detection device 44 described below is also connected to, for example, a power supply device (not shown) provided on the swivel base 12 via a power supply cable. The position information detection device 44 is also connected to a control unit (not shown) provided on the swivel base 12 via a signal transmission cable. The power supply cable to the electric motor 41, the power supply cable to the brake mechanism 42, the power supply cable to the position information detection device 44, and the signal transmission cable of the position information detection device 44 are all integrated into one multi-core cable and arranged in the internal space of the telescopic boom 14. With this configuration, the internal space of the telescopic boom 14 can be efficiently utilized.

[0057] Specifically, the brake mechanism 42 operates when the cylinder connecting mechanism 45 or the boom connecting mechanism 46 is in a contracted state, described below, to maintain the states of the cylinder connecting mechanism 45 and the boom connecting mechanism 46.

[0058] <Transmission mechanism> The transmission mechanism 43 transmits the power of the electric motor 41 to the cylinder connecting mechanism 45 and the boom connecting mechanism 46. The transmission mechanism 43 has a reducer 431 and a transmission shaft 432 (see FIG. 7A).

[0059] The reducer 431 reduces the rotation of the electric motor 41 and transmits it to the transmission shaft 432. The reducer 431 is, for example, a planetary gear mechanism.

[0060] A first end of the transmission shaft 432 is connected to an output shaft (not shown) of the reducer 431. The transmission shaft 432 rotates together with the output shaft of the reducer 431. The transmission shaft 432 extends in the X direction, and is inserted into a housing (not shown) of the pin moving module 4.

[0061] A second end of the transmission shaft 432 protrudes from the housing toward the positive side in the X direction. A position information detection device 44, which will be described later, is provided on the end of the transmission shaft 432 on the positive side in the X direction.

[0062] <Location information detection device> The position information detection device 44 detects information relating to the positions of the pair of cylinder connecting pins 454a, 454b and the pair of boom connecting pins 144a (which may be the pair of boom connecting pins 144b; the same applies below).

[0063] The information about the position may be, for example, the amount of movement of the pair of cylinder connecting pins 454a, 454b or the pair of boom connecting pins 144a from a reference position (the position shown in Fig. 7A and Fig. 8A). The positions of the pair of cylinder connecting pins 454a, 454b shown in Fig. 7A and Fig. 8A are defined as the reference positions of the cylinder connecting pins 454a, 454b. Also, the position of the pair of boom connecting pins 144a shown in Fig. 7A and Fig. 8A is defined as the reference position of the boom connecting pin 144a.

[0064] Information regarding the positions of the pair of cylinder connecting pins 454 a , 454 b and the pair of boom connecting pins 144 a detected by the position information detection device 44 is used for various controls of the actuator 2 , including control of the electric motor 41 .

[0065] <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. 3 and 4) and a contracted state (see Fig. 5). The operation of the cylinder coupling mechanism 45 transitioning from the expanded state to the contracted state is referred to as the unloading 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 referred to as the engaging operation of the cylinder coupling mechanism 45.

[0066] In the expanded state, a pair of cylinder connecting pins 454a, 454b described below and a pair of cylinder pin receivers 141a of the boom (for example, the tip boom 141) are in an engaged state (also referred to as a cylinder pin in-state). In such an engaged state, the boom and the cylinder member 32 are in a connected state. That is, due to the in-state operation of the cylinder connecting mechanism 45, the pair of cylinder connecting pins 454a, 454b are returned to the reference position by a first biasing mechanism 455 described below.

[0067] On the other hand, in the contracted state, the pair of cylinder connecting pins 454a, 454b and the pair of cylinder pin receiving parts 141a (see Figs. 2A to 2E) are in a detached state (the state shown in Fig. 2E, also called the cylinder pin removed state). In this detached state, the boom and the cylinder member 32 are in a non-connected state.

[0068] As shown in Figures 3, 4, and 5, the cylinder connecting mechanism 45 has a first missing tooth gear 450 (see Figures 7A to 7C), a first rack bar 451, a first gear mechanism 452, a second gear mechanism 453, a pair of cylinder connecting pins 454a, 454b, and a first biasing mechanism 455.

[0069] <First missing tooth gear> The first partially toothed gear 450 (also referred to as a switch gear) is substantially circular plate-shaped. The first partially toothed gear 450 has a first tooth portion on a part of its outer circumferential surface. The first partially toothed gear 450 is fitted and fixed to the outside of the transmission shaft 432, and rotates together with the transmission shaft 432. In the present embodiment, the first partially toothed gear 450 is disposed so as to overlap with a second gear mechanism 460, which will be described later, in the front-rear direction. Therefore, the first partially toothed gear 450 is not shown in Figs. 3 to 5.

[0070] The first missing tooth gear 450 constitutes a switch gear together with a second missing tooth gear 460 (see FIG. 3) of the boom connecting mechanism 46. The switch gear selectively transmits the power of the electric motor 41 to either one of the connecting mechanisms, the cylinder connecting mechanism 45 or the boom connecting mechanism 46.

[0071] In the following description, the rotation direction of the first missing tooth gear 450 (indicated by arrow A in FIGS. 7A to 7C ) when the cylinder coupling mechanism 45 transitions from the expanded state (see FIGS. 3, 4, and 7A ) to the contracted state (see FIGS. 5 and 7C ) will be referred to as the rotation direction. 1 The direction indicated by (a) is a first direction in the rotation direction of the first missing tooth gear 450.

[0072] On the other hand, when the cylinder coupling mechanism 45 transitions from the contracted state to the expanded state, the rotation direction of the first missing tooth gear 450 (indicated by arrow A in FIGS. 7A to 7C ) 2 The direction indicated by (a direction indicated by a arrow) is a second direction in the rotation direction of the first missing tooth gear 450.

[0073] <First rack bar> The first rack bar 451 moves in its own longitudinal direction (also referred to as the Y direction) in response to rotation of the first missing tooth gear 450. The first rack bar 451 is located furthest on the negative side in the Y direction in the expanded state (see FIGS. 3 and 4). On the other hand, the first rack bar 451 is located furthest on the positive side in the Y direction in the contracted state (see FIG. 5).

[0074] When the state transitions from the expanded state to the contracted state, if the first missing tooth gear 450 rotates in the first direction, the first rack bar 451 moves to the + side in the Y direction (also referred to as one side in the longitudinal direction).

[0075] On the other hand, when the first missing tooth gear 450 rotates in the second direction during state transition from the contracted state to the expanded state, the first rack bar 451 moves to the negative side in the Y direction (also referred to as the other side in the longitudinal direction).

[0076] The first rack bar 451 has a first rack tooth portion on a surface on the side (also referred to as the + side in the Z direction) closer to the first partially toothed gear 450. The first rack tooth portion meshes with the first tooth portion of the first partially toothed gear 450 only during the above-mentioned state transition.

[0077] In the expanded state, when the first partially toothed gear 450 rotates a predetermined amount in the first direction, the first tooth portion of the first partially toothed gear 450 meshes with the first rack tooth portion of the first rack bar 451. When the first partially toothed gear 450 rotates further in the first direction from this state, the first rack bar 451 moves to the + side in the Y direction in response to the rotation of the first partially toothed gear 450.

[0078] Furthermore, when the first partially toothed gear 450 rotates in the second direction from the expanded state shown in FIG. 3, the first rack tooth portion of the first rack bar 451 and the first tooth portion of the first partially toothed gear 450 do not mesh with each other.

[0079] Moreover, the first rack bar 451 has a second rack tooth portion and a third rack tooth portion on a surface on the side (also referred to as the - side in the Z direction) farther from the first partially toothed gear 450. The second rack tooth portion meshes with a first gear mechanism 452, which will be described later. The third rack tooth portion meshes with a second gear mechanism 453, which will be described later.

[0080] <First gear mechanism> The first gear mechanism 452 has a plurality of gear elements (three in this embodiment) each of which is a spur gear (see FIG. 3). The first gear mechanism 452 meshes with a second rack tooth portion of the first rack bar 451. The first gear mechanism 452 rotates in response to movement of the first rack bar 451 in the Y direction. The first gear mechanism 452 also meshes with a pin side rack tooth portion of one cylinder connecting pin 454a described later.

[0081] <Second gear mechanism> The second gear mechanism 453 has a plurality of gear elements (two in this embodiment) each of which is a spur gear (see FIG. 3). The second gear mechanism 453 meshes with a third rack tooth portion of the first rack bar 451. The second gear mechanism 453 rotates in response to movement of the first rack bar 451 in the Y direction. In addition, the second gear mechanism 453 meshes with a pin side rack tooth portion of the other cylinder connecting pin 454b described later.

[0082] The numbers of gears constituting the first gear mechanism 452 and the second gear mechanism 453 are not limited to those in this embodiment. From the viewpoint of moving one cylinder connecting pin 454a and the other cylinder connecting pin 454b in opposite directions in response to the movement of the first rack bar 451, it is sufficient that the number of gears in the first gear mechanism 452 is an odd number and the number of gears in the second gear mechanism 453 is an even number.

[0083] The number of gears of the first gear mechanism 452 and the number of gears of the second gear mechanism 453 may be determined based on the number of parts of the pin moving module 4 and the dimension in the left-right direction (Y direction). For example, if the number of gears of the first gear mechanism 452 is one, the number of parts can be reduced, but the dimension of the first rack bar 451 in the Y direction becomes large because it is necessary to match the positions in the Y direction of the meshing portion between the first gear mechanism 452 and the first rack bar 451 and the meshing portion between the first gear mechanism 452 and one of the cylinder connecting pins 454a. On the other hand, if the number of gears of the first gear mechanism 452 is three as in this embodiment, the number of parts increases, but the dimension of the first rack bar 451 in the Y direction can be reduced because the meshing portion between the first gear mechanism 452 and the first rack bar 451 can be positioned to the left (− side in the Y direction) of the meshing portion between the first gear mechanism 452 and one of the cylinder connecting pins 454a.

[0084] <Cylinder connecting pin> The pair of cylinder connecting pins 454a, 454b each have a central axis aligned in the Y direction and are coaxial with each other. Each of the pair of cylinder connecting pins 454a, 454b has a pin-side rack tooth portion on its outer circumferential surface. The pin-side rack tooth portion of one of the cylinder connecting pins 454a meshes with the first gear mechanism 452.

[0085] One cylinder connecting pin 454a moves in its axial direction in response to rotation of the first gear mechanism 452. Specifically, one cylinder connecting pin 454a moves to the + side in the Y direction (also referred to as the second direction) when transitioning from the contracted state to the expanded state. On the other hand, the other cylinder connecting pin 454a moves to the - side in the Y direction (also referred to as the first direction) when transitioning from the expanded state to the contracted state.

[0086] The pin-side rack teeth portion of the other cylinder connecting pin 454 b (also referred to as the − side in the Y direction) is in mesh with the second gear mechanism 453 .

[0087] The other cylinder connecting pin 454b moves in its own axial direction in response to rotation of the second gear mechanism 453. Specifically, the other cylinder connecting pin 454b moves to the negative side of the Y direction (also referred to as the second direction) when transitioning from the contracted state to the expanded state. On the other hand, the other cylinder connecting pin 454b moves to the positive side of the Y direction (also referred to as the first direction) when transitioning from the expanded state to the contracted state. In the above-mentioned state transition, the pair of cylinder connecting pins 454a, 454b move in opposite directions to each other in the Y direction.

[0088] The pair of cylinder connecting pins 454a, 454b are inserted into a first through hole of a housing (not shown). Tips of the pair of cylinder connecting pins 454a, 454b each protrude to the outside of the housing.

[0089] <First biasing mechanism> The first biasing mechanism 455 corresponds to an example of a biasing portion and a first biasing member, and returns the cylinder connecting mechanism 45 to the expanded state when the electric motor 41 is de-energized with the cylinder connecting mechanism 45 in the contracted state. In other words, the first biasing mechanism 455 returns the pair of cylinder connecting pins 454a, 454b to the reference position when the electric motor 41 is de-energized (stopped) with the cylinder connecting mechanism 45 in the contracted state. The first biasing mechanism 455 biases the pair of cylinder connecting pins 454a, 454b in directions away from each other.

[0090] In other words, the first biasing mechanism 455 biases the pair of cylinder connecting pins 454a, 454b in a first direction in the axial direction of the pair of cylinder connecting pins 454a, 454b. The first direction in the axial direction of the cylinder connecting pin 454a and the first direction in the axial direction of the cylinder connecting pin 454b are opposite directions with respect to the Y direction.

[0091] The first biasing mechanism 455 may directly bias the cylinder connecting pins 454a, 454b, or may indirectly bias the cylinder connecting pins 454a, 454b via another member.

[0092] Specifically, the first biasing mechanism 455 has a pair of coil springs 455a, 455b (see FIG. 3). Each of the pair of coil springs 455a, 455b corresponds to an example of a second spring, and biases the pair of cylinder connecting pins 454a, 454b toward a first direction in the axial direction of the cylinder connecting pins 454a, 454b. When the brake mechanism 42 is operating, the cylinder connecting mechanism 45 does not transition from the contracted state to the expanded state.

[0093] <Boom connection mechanism> The boom connection mechanism 46 transitions between an extended state (see FIGS. 3 and 5) and a retracted state (see FIG. 4) 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 referred to as the extraction 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 referred to as the engagement operation of the boom connection mechanism 46.

[0094] In the extended state, the boom connection mechanism 46 can be in either an engaged state or a disengaged state with respect to the boom connection pins (for example, the pair of boom connection pins 144a).

[0095] The boom connection mechanism 46, while engaged with the boom connection pin, transitions from the extended state to the contracted state, thereby disengaging the boom connection pin from the boom.

[0096] Furthermore, the boom connection mechanism 46, while engaged with the boom connecting pin, transitions from the contracted state to the extended state, thereby engaging the boom connecting pin with the boom. In other words, the boom connection pin is returned to its reference position by the second biasing mechanism 463, which will be described later, due to the closing operation of the boom connection mechanism 46.

[0097] As shown in FIG. 3, the boom connecting mechanism 46 has a second missing tooth gear 460, a pair of second rack bars 461a, 461b, a synchronous gear 462 (see FIGS. 8A to 8C), and a second biasing mechanism 463.

[0098] <Second missing tooth gear> The second partially toothed gear 460 (also referred to as a switch gear) is in a substantially circular plate shape, and has a second tooth portion on a part of the outer circumferential surface in the circumferential direction.

[0099] The second partially toothed gear 460 is fitted and fixed to the transmission shaft 432 on the positive side in the X direction relative to the first partially toothed gear 450, and rotates together with the transmission shaft 432. Note that the second partially toothed gear 460 may be a partially toothed gear that is integral with the first partially toothed gear 450.

[0100] Hereinafter, the rotation direction of the second missing tooth gear 460 (indicated by arrow A in FIGS. 3 and 8A to 8C ) when the boom connecting mechanism 46 transitions from the extended state (see FIGS. 3 and 5 ) to the contracted state (see FIG. 4 ) will be referred to as the rotation direction of the second missing tooth gear 460 (indicated by arrow A in FIGS. 3 and 8A to 8C ). 2 The direction indicated by (a) is a first direction in the rotation direction of the second missing tooth gear 460.

[0101] On the other hand, when the boom connecting mechanism 46 transitions from the contracted state to the extended state, the rotation direction of the second missing tooth gear 460 (indicated by arrow A in FIGS. 3 and 8A to 8C ) 1 The direction indicated by (a direction indicated by a arrow) is a second direction in the rotation direction of the second missing tooth gear 460.

[0102] 3 is a diagram of the pin moving module 4 viewed from the +X direction. Therefore, in this embodiment, the first and second directions in the rotation direction of the second missing tooth gear 460 are opposite to the first and second directions in the rotation direction of the first missing tooth gear 450.

[0103] In other words, the rotation direction of the second missing tooth gear 460 when the boom connecting mechanism 46 transitions from the extended state to the retracted state is opposite to the rotation direction of the first missing tooth gear 450 when the cylinder connecting mechanism 45 transitions from the extended state to the retracted state.

[0104] <Second rack bar> Each of the pair of second rack bars 461a, 461b moves in the Y direction (also referred to as the axial direction) with rotation of the second missing tooth gear 460. One second rack bar 461a (positive side of the X direction) and the other second rack bar 461b (negative side of the X direction) move in opposite directions in the Y direction.

[0105] The pair of second rack bars 461a, 461b are, for example, shaft members that are long in the Y direction and are arranged parallel to each other. The pair of second rack bars 461a, 461b are each arranged on the + side in the Z direction relative to the first rack bar 451.

[0106] The pair of second rack bars 461a, 461b each have a synchronizing rack tooth portion on a side surface facing each other in the X direction. The synchronizing rack tooth portion each meshes with a synchronizing gear 462. When the synchronizing gear 462 rotates, one second rack bar 461a and the other second rack bar 461b move in opposite directions in the Y direction.

[0107] The pair of second rack bars 461a, 461b have locking claw portions 461g, 461h at their tips, respectively. When a boom connecting pin (for example, boom connecting pins 144a, 144b) is moved, the locking claw portions 461g, 461h engage with pin side receiving portions 144c (see FIG. 3) provided on the boom connecting pin.

[0108] One of the second rack bars 461a has a driving rack tooth portion 461c (see FIG. 3) on a side surface facing the second partially toothed gear 460. The driving rack tooth portion 461c meshes with the second tooth portion of the second partially toothed gear 460.

[0109] When the second missing tooth gear 460 rotates a predetermined amount in the first direction from the expanded state, the driving rack tooth portion 461c meshes with the second tooth portion of the second missing tooth gear 460. When the second missing tooth gear 460 rotates further in the first direction, one of the second rack bars 461a moves to the + side in the Y direction based on the meshing between the driving rack tooth portion 461c and the second tooth portion of the second missing tooth gear 460.

[0110] Furthermore, when one second rack bar 461a moves to the + side in the Y direction, the synchronous gear 462 rotates and the other second rack bar 461b moves to the - side in the Y direction (i.e., the opposite side to the one second rack bar 461a).

[0111] <Second biasing mechanism> The second biasing mechanism 463 corresponds to an example of a biasing section and a second biasing member, and returns the boom connection mechanism 46 to the extended state when the electric motor 41 is de-energized in the contracted state of the boom connection mechanism 46. In other words, the second biasing mechanism 463 returns the boom connection pins (e.g., a pair of boom connection pins 144a) to the reference position when the electric motor 41 is de-energized (stopped) in the contracted state of the second biasing mechanism 463. Note that when the brake mechanism 42 is operating, the boom connection mechanism 46 does not transition from the contracted state to the extended state.

[0112] The second biasing mechanism 463 biases the pair of second rack bars 461a, 461b in directions away from each other. In other words, in a state in which the boom connection mechanism 46 and a boom connection pin (for example, a pair of boom connection pins 144a) are engaged with each other, the second biasing mechanism 463 indirectly biases the boom connection pin in a first direction in the axial direction of the boom connection pin via the pair of second rack bars 461a, 461b.

[0113] Specifically, the second biasing mechanism 463 is composed of a pair of coil springs 463a, 463b (see FIG. 8A). Each of the pair of coil springs 463a, 463b corresponds to an example of a first spring, and biases the base ends of the pair of second rack bars 461a, 461b toward the tip side.

[0114] <Control Unit> The control unit 47 is, for example, an in-vehicle computer (processor) that is configured with an input terminal, an output terminal, a CPU, a memory, etc. The functions of the control unit 47 may be realized by a control circuit.

[0115] The control unit 47 as described above is mounted on the mobile crane 1 (specifically, the swivel base 12). However, the location of the control unit 47 is not limited to the swivel base 12. The control unit 47 controls switches 62 to 66 of the electric circuit 6 described below. Specific functions of the control unit 47 will be described later together with the configuration of the electric circuit 6.

[0116] <Electric circuit> Next, the electric circuit 6 will be described with reference to Figures 6A to 6E. The electric circuit 6 realizes a plurality of states by switching switches under the control of the control unit 47. The plurality of states realized by the electric circuit 6 will be described later.

[0117] The electric circuit 6 includes a power supply unit 61 , a first switch 62 , a second switch 63 , a third switch 64 , a fourth switch 65 , a fifth switch 66 , and the electric motor 41 .

[0118] The power supply device 61 is provided, for example, on the swivel base 12 (see FIG. 1).

[0119] The first switch 62 is provided on the first line 6L1. The first switch 62 can be in either an ON state or an OFF state under the control of the control unit 47 (see FIG. 1).

[0120] The second switch 63 is provided in the first line 6L1 in series with the first switch 62. The second switch 63 is provided in the first line 6L1 downstream in the direction of current flow from the first switch 62. The second switch 63 can be in either an ON state or an OFF state under the control of the control unit 47.

[0121] The first switch 62 and the second switch 63 are configured as a first relay circuit 681. Based on a command signal from the control unit 47, the first relay circuit 681 sets one of the first switch 62 and the second switch 63 to an ON state and sets the other switch to an OFF state.

[0122] The third switch 64 is provided in the second line 6L2. The second line 6L2 is provided in parallel with the first line 6L1. The third switch 64 can be in either an ON state or an OFF state under the control of the control unit 47.

[0123] The fourth switch 65 is provided in series with the third switch 64 on the second line 6L2. The fourth switch 65 is provided on the second line 6L2 downstream in the direction of current flow (hereinafter simply referred to as the "downstream side") of the third switch 64. The fourth switch 65 can be in either an ON state or an OFF state under the control of the control unit 47.

[0124] The third switch 64 and the fourth switch 65 are configured as a second relay circuit 682. Based on a command signal from the control unit 47, the second relay circuit 682 sets one of the third switch 64 and the fourth switch 65 to an ON state and sets the other switch to an OFF state.

[0125] The fifth switch 66 is configured by a third relay circuit 683, and is provided in the third line 6L3. The third line 6L3 is provided in series with the first line 6L1 and the second line 6L2 on the downstream side of the first line 6L1 and the second line 6L2. The fifth switch 66 (third relay circuit 683) can be in either an ON state or an OFF state under the control of the control unit 47.

[0126] The configuration of the electric motor 41 is as described above. The electric motor 41 is provided in the fourth line 6L4. The fourth line 6L4 connects a portion of the first line 6L1 between the first switch 62 and the second switch 63 and a portion of the second line 6L2 between the third switch 64 and the fourth switch 65.

[0127] The above-mentioned electric circuit 6 can be in a first drive state shown in FIG. 6A, a second drive state shown in FIG. 6B, a first release state shown in FIG. 6C, a second release state shown in FIG. 6D, and a braking state shown in FIG. 6E.

[0128] <First driving state> The first drive state of the electric circuit 6 corresponds to the first state of the electric circuit 6, and is a state in which a current flows in a first direction through the electric motor 41, as shown in Fig. 6A. The first direction is a direction from the first line 6L1 to the second line 6L2 in the fourth line 6L4. In the first drive state of the electric circuit 6, a current flows through a circuit shown by a thick line in Fig. 6A.

[0129] In the first drive state of the electric circuit 6, the electric motor 41 rotates in a first direction. In the first drive state of the electric circuit 6, the first switch 62, the fourth switch 65, and the fifth switch 66 are in an ON state. In addition, in the first drive state of the electric circuit 6, the second switch 63 and the third switch 64 are in an OFF state. The first drive state corresponds to an example of a drive state of the electric circuit.

[0130] The first drive state of the electric circuit 6 is a state for transitioning the cylinder coupling mechanism 45 from the expanded state to the contracted state (the removal operation of the cylinder coupling mechanism 45). When the removal operation of the cylinder coupling mechanism 45 is to be realized, the control unit 47 switches the electric circuit 6 to the first drive state.

[0131] <Second driving state> The second drive state of the electric circuit 6 corresponds to the second state of the electric circuit 6, and is a state in which a current flows in a second direction through the electric motor 41 as shown in Fig. 6B. The second direction is a direction from the second line 6L2 to the first line 6L1 in the fourth line 6L4. In the second drive state of the electric circuit 6, a current flows through a circuit shown by a thick line in Fig. 6B.

[0132] In the second drive state of the electric circuit 6, the electric motor 41 rotates in a second direction. In the second drive state of the electric circuit 6, the second switch 63, the third switch 64, and the fifth switch 66 are in an ON state. In addition, in the second drive state of the electric circuit 6, the first switch 62 and the fourth switch 65 are in an OFF state.

[0133] The second drive state of the electric circuit 6 is a state for causing the boom connection mechanism 46 to transition from the extended state to the contracted state (performing the uncoiling operation of the boom connection mechanism 46). When realizing the uncoiling operation of the boom connection mechanism 46, the control unit 47 switches the electric circuit 6 to the second drive state.

[0134] <First release state> The first open state of the electric circuit 6 corresponds to an example of the third state of the electric circuit 6, and is a state in which no current flows through the electric motor 41 (non-driven state) as shown in FIG. 6C.

[0135] In the first open state of the electric circuit 6, the first switch 62 and the fourth switch 65 are in the ON state. In addition, in the first open state of the electric circuit 6, the second switch 63, the third switch 64, and the fifth switch 66 are in the OFF state. That is, in the first open state of the electric circuit 6, the second switch 63 provided in the closed circuit 67 (the circuit shown by the thick line in FIG. 6E) formed including the electric motor 41 is opened (set to the OFF state).

[0136] The control unit 47 switches the electric circuit 6 to the first release state when the cylinder connecting mechanism 45 transitions from the contracted state to the expanded state (the closing operation of the cylinder connecting mechanism 45). In other words, the control unit 47 switches the electric circuit 6 to the first release state when the pair of cylinder connecting pins 454a, 454b move due to the biasing force received from the first biasing mechanism 455. Note that the instruction to cause the cylinder connecting mechanism 45 to perform the closing operation may be, for example, an instruction based on an operation input from an operator, or an instruction based on a program pre-installed in the control unit 47.

[0137] In the first open state of the electric circuit 6, a closed circuit including the electric motor 41 is not formed in the electric circuit 6. The reason for adopting such a configuration will be explained below.

[0138] During the turning-on operation of the cylinder connecting mechanism 45, when the electric circuit 6 is in the first release state and the brake mechanism 42 is in the released state, the pair of cylinder connecting pins 454a, 454b move in the first direction in the axial direction based on the biasing force of the first biasing mechanism 455. Then, with the movement of the pair of cylinder connecting pins 454a, 454b, the first missing tooth gear 450 moves in the direction of arrow A in FIG. 2 Rotate in the direction of.

[0139] The electric motor 41 rotates idly based on the rotation of the first missing tooth gear 450. At this time, when a closed circuit 67 (a circuit shown by a thick line in FIG. 6E) including the electric motor 41 is formed in the electric circuit 6 as shown in FIG. 6E, the electric motor 41 generates an electromotive force based on its own idling.

[0140] The current generated by the electric motor 41 passes through the closed circuit 67 and returns to the electric motor 41. Then, a Lorentz force is generated in the electric motor 41 based on the current returned to the electric motor 41. This Lorentz force acts as a braking force on the electric motor 41. The current is converted into thermal energy by a resistor (not shown) provided in the closed circuit 67. Such a braking force also acts on the first partially toothed gear 450 as a resistance force against the rotation of the first partially toothed gear 450.

[0141] As described above, when the closed circuit 67 is formed in the electric circuit 6, the moving speed of the pair of cylinder connecting pins 454a, 454b in the first direction is slowed down due to the braking force. As a result, the time required for the closing operation of the cylinder connecting mechanism 45 becomes longer, and there is a possibility that the working efficiency will decrease.

[0142] Therefore, in this embodiment, the control unit 47 switches the switches 62 to 66 of the electric circuit 6 so that a closed circuit 67 is not formed in the electric circuit 6 during the closing operation of the cylinder connecting mechanism 45 (in other words, when the pair of cylinder connecting pins 454a, 454b return). Therefore, during the closing operation of the cylinder connecting mechanism 45, when the electric motor 41 rotates idly, no current flows through the electric motor 41. As a result, the generation of the above-mentioned braking force can be suppressed during the closing operation of the cylinder connecting mechanism 45. Therefore, the time required for the closing operation of the cylinder connecting mechanism 45 is shortened, and the work efficiency can be improved.

[0143] The control unit 47 may set the state of the electric circuit 6 to the first release state throughout the entire process from the start to the end of the closing operation of the cylinder connecting mechanism 45. However, the control unit 47 may set the electric circuit 6 to the first release state from the start of the closing operation of the cylinder connecting mechanism 45 until the closing operation of the cylinder connecting mechanism 45 satisfies a predetermined condition.

[0144] Thereafter, the control unit 47 may set the state of the electric circuit 6 to the state (braking state) shown in FIG. 6E during the period from when the closing operation of the cylinder connecting mechanism 45 satisfies a predetermined condition until it is completed.

[0145] In the braking state of the electric circuit 6, the first switch 62 and the third switch 64 are in the OFF state. In addition, in the braking state of the electric circuit 6, the second switch 63 and the fourth switch 65 are in the ON state. In the braking state of the electric circuit 6, the fifth switch 66 may be in the ON state or the OFF state. The braking state of the electric circuit 6 means a state in which a closed circuit including the electric motor 41 is formed in the electric circuit 6.

[0146] The predetermined condition corresponds to, for example, a case where the axial movement distance of the pair of cylinder connecting pins 454a, 454b in the first direction is equal to or less than a predetermined distance. Therefore, when the axial movement distance of the cylinder connecting pins 454a, 454b in the first direction is equal to or less than a predetermined distance from the start of the closing operation of the cylinder connecting mechanism 45, the control unit 47 sets the electric circuit 6 to the first release state. After that, the control unit 47 sets the state of the electric circuit 6 to the state (braking state) shown in FIG. 6E from the time when the axial movement distance of the cylinder connecting pins 454a, 454b in the first direction exceeds the predetermined distance until the closing operation of the cylinder connecting mechanism 45 is completed.

[0147] As described above, in the braking state of the electric circuit 6, the braking force acts on the first partially toothed gear 450. As a result, it becomes easier to stop the first partially toothed gear 450 at a desired position (reference position).

[0148] <Second Release State> The second open state of the electric circuit 6 corresponds to an example of the third state of the electric circuit 6, and is a state in which no current flows through the electric motor 41 (non-driven state) as shown in FIG. 6D.

[0149] In the second open state of the electric circuit 6, the second switch 63 and the third switch 64 are in the ON state. In addition, in the second open state of the electric circuit 6, the first switch 62, the fourth switch 65, and the fifth switch 66 are in the OFF state. That is, in the second open state of the electric circuit 6, the fourth switch 65 provided in the closed circuit 67 (the circuit shown by the thick line in FIG. 6E) formed including the electric motor 41 is opened (set to the OFF state).

[0150] The control unit 47 switches the electric circuit 6 to the second release state when the boom connection mechanism 46 transitions from the contracted state to the extended state (the boom connection mechanism 46 performs the closing operation). In other words, the control unit 47 switches the electric circuit 6 to the second release state when a boom connection pin (for example, a pair of boom connection pins 144a) moves due to the biasing force received from the second biasing mechanism 463. Note that the instruction to perform the closing operation of the boom connection mechanism 46 may be, for example, an instruction based on an operation input from an operator, or an instruction based on a program pre-installed in the control unit 47.

[0151] In the second open state of the electric circuit 6, a closed circuit including the electric motor 41 is not formed in the electric circuit 6. The reason for adopting such a configuration will be explained below.

[0152] During the opening operation of the boom connecting mechanism 46, when the electric circuit 6 is in the second release state and the brake mechanism 42 is in the released state, the boom connecting pin (for example, a pair of boom connecting pins 144a) moves in the first direction in the axial direction based on the biasing force of the second biasing mechanism 463. Then, with the movement of the boom connecting pin, the second missing tooth gear 460 moves in the direction of the arrow A in FIG. 1 Rotate in the direction of.

[0153] The electric motor 41 rotates idly based on the rotation of the second missing tooth gear 460. At this time, for the same reason as described in the first released state of the electric circuit 6, when a closed circuit 67 (see FIG. 6E) is formed in the electric circuit 6, the moving speed of the boom connecting pin in the first direction slows down due to the braking force.

[0154] Therefore, in this embodiment, the control unit 47 switches the switches 62 to 66 of the electric circuit 6 so that a closed circuit 67 is not formed in the electric circuit 6 during the closing operation of the boom connection mechanism 46 (in other words, when the pair of boom connection pins 144a return). Therefore, during the closing operation of the boom connection mechanism 46, when the electric motor 41 rotates idly, no current flows through the electric motor 41. As a result, the generation of the above-mentioned braking force during the closing operation of the boom connection mechanism 46 can be suppressed. Therefore, the time required for the closing operation of the boom connection mechanism 46 is shortened, and work efficiency can be improved.

[0155] The control unit 47 may set the state of the electric circuit 6 in the second release state throughout the entire process from the start to the end of the retracting operation of the boom connection mechanism 46. However, the control unit 47 may set the state of the electric circuit 6 in the second release state from the start of the retracting operation of the boom connection mechanism 46 until the retracting operation of the boom connection mechanism 46 satisfies a predetermined condition. After that, the control unit 47 may set the state of the electric circuit 6 in the braking state as shown in Fig. 6E from the start to the end of the retracting operation of the boom connection mechanism 46 satisfying the predetermined condition.

[0156] As described above, in the braking state of the electric circuit 6, the braking force acts on the second partially toothed gear 460. As a result, it becomes easier to stop the second partially toothed gear 460 at a desired position (reference position).

[0157] <Operation of the connecting mechanism> An example of the operation of the cylinder connecting mechanism 45 and the boom connecting mechanism 46 will now be briefly described.

[0158] <Operation of cylinder connection mechanism> First, an example of the operation of the cylinder connecting mechanism 45 will be described with reference to FIGS. 2A to 2E and 7A to 7C.

[0159] Fig. 7A is a schematic diagram showing the expanded state of the cylinder connecting mechanism 45 and the engagement state between the pair of cylinder connecting pins 454a, 454b and the pair of cylinder pin receiving portions 141a of the tip boom 141. Fig. 7B is a schematic diagram showing the state in which the cylinder connecting mechanism 45 is in the middle of transitioning from the expanded state to the contracted state. Furthermore, Fig. 7C is a schematic diagram showing the contracted state of the cylinder connecting mechanism 45 and the disengagement state between the pair of cylinder connecting pins 454a, 454b and the pair of cylinder pin receiving portions 141a of the tip boom 141.

[0160] The expanded state of the cylinder connecting mechanism 45 shown in Fig. 7A corresponds to the state of the cylinder connecting mechanism 45 in Fig. 2A to Fig. 2D. The state of the cylinder connecting mechanism 45 shown in Fig. 7B corresponds to a state in the middle of transition from the state of the cylinder connecting mechanism 45 shown in Fig. 2D to the state of the cylinder connecting mechanism 45 shown in Fig. 2E. The contracted state of the cylinder connecting mechanism 45 shown in Fig. 7C corresponds to the state of the cylinder connecting mechanism 45 shown in Fig. 2E.

[0161] The cylinder coupling mechanism 45 transitions from the expanded state (see FIGS. 3, 4, and 7A) to the contracted state (see FIGS. 5 and 7C) based on the power of the electric motor 41. In addition, the cylinder coupling mechanism 45 transitions from the contracted state (see FIGS. 5 and 7C) to the expanded state (see FIGS. 3, 4, and 7A) based on the biasing force of the first biasing mechanism 455.

[0162] 7A to 7C, the first missing tooth gear 450 and the second missing tooth gear 460 are shown typically as an integrated missing tooth gear. For ease of explanation, this integrated missing tooth gear will be described below as the first missing tooth gear 450. The position of the first missing tooth gear 450 shown in FIG.

[0163] When the cylinder connecting mechanism 45 transitions from the expanded state to the contracted state, the control unit 47 switches the electric circuit 6 to the first driving state (see FIG. 6A). The power of the electric motor 41 is transmitted to a pair of cylinder connecting pins 454a, 454b via the following first and second paths.

[0164] The first path is a path from the first partially-toothed gear 450 → the first rack bar 451 → the first gear mechanism 452 → one cylinder connecting pin 454a.

[0165] The second path is the path of the first partially toothed gear 450 → the first rack bar 451 → the second gear mechanism 453 → the other cylinder connecting pin 454b.

[0166] Specifically, first, in the first path and the second path, the first partially-toothed gear 450 rotates in a first direction (arrow A in FIG. 7A ) based on the power of the electric motor 41. 1 The axis rotates in the direction indicated by .

[0167] In the first path, when the first partially toothed gear 450 rotates in the first direction, the first rack bar 451 moves to the + side in the Y direction (the right side in FIGS. 7A to 7C) in response to the rotation.

[0168] In the first path, when the first rack bar 451 moves to the + side in the Y direction, one cylinder connecting pin 454a moves to the - side in the Y direction (the left side in Figs. 7A to 7C) via the first gear mechanism 452. The - side in the Y direction corresponds to a second direction in the axial direction of the one cylinder connecting pin 454a.

[0169] On the other hand, in the second path, when the first rack bar 451 moves to the + side in the Y direction, the other cylinder connecting pin 454b moves to the + side in the Y direction via the second gear mechanism 453. The + side in the Y direction corresponds to a second direction in the axial direction of the other cylinder connecting pin 454b.

[0170] The position information detection device 44 detects that the pair of cylinder connecting pins 454a, 454b have been released from the pair of cylinder pin receiving portions 141a of the tip boom 141 and have moved to a predetermined position (for example, the positions shown in Figs. 2E and 7C). Then, based on the detection result, the control unit 47 stops the operation of the electric motor 41.

[0171] 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 released while the electric motor 41 is in the non-energized state.

[0172] When the cylinder coupling mechanism 45 transitions from the contracted state to the expanded state, the control unit 47 switches the electric circuit 6 to the first released state (see FIG. 6C). In the first released state of the electric circuit 6, a closed circuit including the electric motor 41 is not formed in the electric circuit 6. Therefore, as described above, the time required for the closing operation of the cylinder coupling mechanism 45 is shortened, and the working efficiency can be improved.

[0173] <Boom connection mechanism operation> First, an example of the operation of the boom connecting mechanism 46 will be described with reference to FIGS. 2A to 2E and 8A to 8C.

[0174] Fig. 8A is a schematic diagram showing the boom connection mechanism 46 in an extended state, and an engaged state between the pair of boom connecting pins 144a and the pair of first boom pin receivers 142b of the intermediate boom 142. Fig. 8B is a schematic diagram showing the boom connection mechanism 46 in the middle of transitioning from the extended state to the contracted state. Furthermore, Fig. 8C is a schematic diagram showing the boom connection mechanism 46 in a contracted state, and a disengaged state between the pair of boom connecting pins 144a and the pair of first boom pin receivers 142b of the intermediate boom 142.

[0175] The extended state of the boom connection mechanism 46 shown in Figure 8A corresponds to the state of the boom connection mechanism 46 in Figure 2A. The state of the boom connection mechanism 46 shown in Figure 8B corresponds to a state in the middle of transition from the state of the boom connection mechanism 46 shown in Figure 2A to the state of the boom connection mechanism 46 shown in Figure 2B. The retracted state of the boom connection mechanism 46 shown in Figure 8C corresponds to the state of the boom connection mechanism 46 shown in Figure 2B.

[0176] The boom connection mechanism 46 transitions between an extended state (see FIG. 8A) and a retracted state (see FIG. 8C) based on the power of the electric motor 41.

[0177] 8A to 8C, the first missing tooth gear 450 and the second missing tooth gear 460 are shown typically as an integrated missing tooth gear. For ease of explanation, this integrated missing tooth gear will be described below as the second missing tooth gear 460. The position of the second missing tooth gear 460 shown in FIG. 8A is defined as the reference position of the second missing tooth gear 460.

[0178] When the boom connection mechanism 46 transitions from the extended state to the retracted state, the control unit 47 switches the electric circuit 6 to the second drive state (see FIG. 6B). The power of the electric motor 41 is transmitted through the second missing tooth gear 460 → one second rack bar 461a → the synchronous gear 462 → the other second rack bar 461b.

[0179] First, in the above-mentioned path, the second partially-toothed gear 460 rotates in a first direction (arrow A in FIG. 3 and FIG. 8A to FIG. 8C ) based on the power of the electric motor 41. 2 The axis rotates in the direction indicated by .

[0180] When the second partially toothed gear 460 rotates in the first direction, one of the second rack bars 461a moves to the + side in the Y direction (the right side in FIGS. 8A to 8C) in response to the rotation.

[0181] Then, in response to the movement of one second rack bar 461a toward the + side in the Y direction, the synchronization gear 462 rotates. Then, in response to the rotation of the synchronization gear 462, the other second rack bar 461b moves toward the - side in the Y direction (the left side in FIGS. 8A to 8C).

[0182] 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 contracted 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 8C).

[0183] The position information detection device 44 detects that the pair of boom connecting pins 144a have been released from 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. 2B and FIG. 8C). Then, based on this detection result, the control unit 47 stops the operation of the electric motor 41.

[0184] As described above, in this embodiment, the retracting operation of the cylinder connecting mechanism 45 and the retracting operation of the boom connecting mechanism 46 are prevented from being performed simultaneously.

[0185] Specifically, when the first tooth portion of the first missing tooth gear 450 in the cylinder connecting mechanism 45 is engaged with the first rack tooth portion of the first rack bar 451, the second tooth portion of the second missing tooth gear 460 in the boom connecting mechanism 46 does not engage with the drive rack tooth portion of one of the second rack bars 461a.

[0186] Conversely, when the second tooth portion of the second missing tooth gear 460 in the boom connecting mechanism 46 is engaged with the driving rack tooth portion of one of the second rack bars 461a, the first tooth portion of the first missing tooth gear 450 in the cylinder connecting mechanism 45 does not engage with the first rack tooth portion of the first rack bar 451.

[0187] When the brake mechanism 42 is released while the electric motor 41 is in a non-energized state, the closing operation of the boom connecting mechanism 46 is automatically performed based on the biasing force of the second biasing mechanism 463. During this state transition, the pair of boom connecting pins 144a move in directions away from each other.

[0188] The position information detection device 44 detects that the pair of boom connecting pins 144a engage with the pair of first boom pin receiving portions 142b of the intermediate boom 142 and move to a predetermined position (for example, the position shown in FIG. 2A and FIG. 8A). The detection result is used to control the next operation of the actuator 2.

[0189] When the boom connection mechanism 46 transitions from the contracted state to the extended state, the control unit 47 switches the electric circuit 6 to the second released state (see FIG. 6D). In the second released state of the electric circuit 6, a closed circuit including the electric motor 41 is not formed in the electric circuit 6. Therefore, as described above, the time required for the closing operation of the boom connection mechanism 46 is shortened, and the work efficiency can be improved.

[0190] <Actions and Effects of This Embodiment> In the case of the mobile crane 1 of this embodiment having the above-mentioned configuration, as described above, it is possible to shorten the time required for the closing operation of the cylinder connecting mechanism 45 and the closing operation of the boom connecting mechanism 46. As a result, it is possible to improve the working efficiency of the extension and retraction work of the telescopic boom 14.

[0191] <Additional Notes> The working machine according to the present invention comprises: A plurality of booms that are extended and retracted by the power of an actuator; a first pin that moves by a first spring to connect adjacent booms and moves by power of a motor to release the connection; It basically comprises a second pin that moves by a second spring to connect the boom and the actuator and moves by the power of the motor to release the connection.

[0192] The technical ideas disclosed in the specification and drawings include inventions obtained by combining the various configurations described in the above embodiments in any desired manner. In particular, the technical ideas disclosed in the specification and drawings include inventions obtained by applying the various configurations disclosed in the specification and drawings in any desired combination to the above basic configuration. [Industrial Applicability]

[0193] The crane according to the present invention is not limited to a rough terrain crane, but may be, for example, various types of mobile cranes such as an all-terrain crane, a truck crane, or a loaded truck crane (also called a cargo crane). Furthermore, the crane according to the present invention is not limited to a mobile crane, but may be any other crane equipped with a telescopic boom. [Explanation of symbols]

[0194] 1 Mobile crane 10 Running body 101 Wheels 11 Outrigger 12 Swivel table 14 Telescopic boom 141 Boom tip 141a Cylinder pin receiving part 141b Boom pin receiver 142 Intermediate boom 142a Cylinder pin receiving part 142b First boom pin receiver 142c Second boom pin receiver 142d Third boom pin receiver 143 Base boom 144a, 144b Boom connecting pin 144c Pin side receiving part 15. Dinghy cylinder 16 Wire Rope 17 Hook 2 Actuators 3 Telescopic cylinder 31 Rod member 32 Cylinder parts 4 pin transfer module 41 Electric motor 42 Brake mechanism 43 Transmission Mechanism 431 Reducer 432 Transmission shaft 44 Location information detection device 45 Cylinder connection mechanism 450 First missing tooth gear 451 First Rack Bar 451a First rack tooth part 451b Second rack tooth part 451c Third rack tooth part 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 460 Second missing tooth gear 461a, 461b Second rack bar 461c Driving rack teeth 461g, 461h Locking claw part 462 Synchronous Gear 463 Second biasing mechanism 463a, 463b Coil spring 47 Control Unit 6 Electrical Circuits 61 Power supply 62 First Switch 63 Second Switch 64 Third Switch 65 Fourth Switch 66 Fifth Switch 67 Closed circuit 681 First Relay Circuit 682 Second Relay Circuit 683 Third Relay Circuit 6L1 First Line 6L2 Second Line 6L3 Third Line 6L4 4th Line

Claims

1. A plurality of booms that are extended and retracted by the power of an actuator; a first pin that moves by a first spring to connect adjacent booms and moves by power of a motor to release the connection; a second pin that moves by a second spring to connect the boom and the actuator and moves by power of the motor to release the connection; a circuit configured to generate no current based on idling of the motor accompanying the movement of the first pin or the second pin when the first pin is moved by the first spring or the second pin is moved by the second spring. Work machine.

2. 2. The work machine according to claim 1, further comprising a control unit that opens a closed circuit formed including the motor by opening a switch provided in the circuit when the first pin is moved by the first spring or the second pin is moved by the second spring.

3. The work machine according to claim 2 , wherein the control unit opens a switch provided in the closed circuit when the first pin is moved by the first spring or when the second pin is moved by the second spring.

4. The work machine according to any one of claims 1 to 3, wherein the motor is configured by a single motor, is driven when the first pin is moved and when the second pin is moved, and is stopped when the first pin is moved by the first spring and when the second pin is moved by the second spring.

5. The work machine according to claim 4 , wherein the direction of rotation of the motor is changed based on switching of a switch provided in the circuit.

6. The circuit comprises: a first state in which the motor rotates in a first direction and drives the first pin; a second state in which the motor rotates in a second direction and drives the second pin; and The work machine according to claim 5 , wherein the work machine is configured to be capable of taking any one of a third state in which the motor is stopped and a closed circuit including the motor is not formed in the circuit.

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