Grip-type work vehicle

Abstract

To enable rotation of a columnar object about a center axis thereof while gripping the columnar object such as an electric pole.SOLUTION: This grip-type work vehicle comprises: a vehicle body; a boom provided on the vehicle body to be able to turn, undulate, and elongate / contract; a grip 80 that grips a columnar object; a support mechanism for changing the attitude of the grip 80 with respect to the tip of the boom; and a control device that controls operations of the boom and the support mechanism. The control device can perform control to horizontally move the grip by combining turning, undulating and elongating operation control of the boom with operation control of the support mechanism, and the support mechanism has a horizontal swing mechanism of causing the grip 80 to perform a horizontal swing operation. The control device performs control to horizontally swing the grip 80, control to turn the boom, and control to horizontally and vertically move the grip 80 in combination with a columnar object P vertically extending to be gripped by the grip 80, and performs control to rotate the gripped columnar object P about a center axis extending in a vertical direction.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a gripping type working vehicle used for gripping pole-shaped objects such as utility poles and performing pole erection work. [Background technology]

[0002] As an example of a gripping type work vehicle, a gripping type pole hole digger vehicle is known, which includes a swivel table provided on a vehicle body so as to be freely rotatable, a boom provided on the swivel table so as to be freely raised and lowered, an auger device attached to the boom for digging a pole hole for erecting a utility pole, and a gripping device provided at the tip of the boom for gripping a pole-shaped object such as a utility pole (see, for example, Patent Document 1). When using the pole hole digger vehicle to excavate a pole hole in the ground, the boom is appropriately operated with the auger device suspended from the tip of the boom, and the auger device is rotated at a predetermined excavation position to form a pole hole of a predetermined depth. After the excavation of the pole hole is completed, the auger device is lifted up and stored on the side of the boom, and the utility pole is gripped by the gripping device provided at the tip of the boom, and the boom is appropriately operated with the utility pole being gripped, so that the utility pole can be directly erected into the excavated pole hole. A pole hole digger equipped with such a gripping device can perform a series of pole erection work more efficiently than when the pole is hoisted using a winch or crane, etc. Note that there are also work vehicles equipped only with a gripping device without an auger device, so these will be collectively referred to as a gripping type work vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2-81892 Summary of the Invention [Problem to be solved by the invention]

[0004] One type of utility pole that is erected in this way is called a flanged split pole. A flanged split pole is composed of a lower utility pole that is installed by inserting it into a pole hole excavated in the ground, and an upper utility pole that is connected to the upper end of the lower utility pole thus erected in the ground, and the flanges provided at the upper end of the lower utility pole and the lower end of the upper utility pole are bolted together. When erecting such a flanged split pole using a gripping work vehicle, after an erection hole is excavated with an auger device, the lower utility pole is gripped by a gripping device provided at the tip of the boom, and the lower utility pole is inserted into the pole hole and fixed by filling the hole. Next, the upper utility pole is gripped by the gripping device, and the flange at the lower end of the upper utility pole is brought into contact with or close to the upper end of the flange at the upper end of the erected lower utility pole. The two flanges are then bolted together, and at this time, the bolt insertion holes of the two flanges need to be aligned, and alignment adjustment is required (adjustment to rotate the upper utility pole around an axis extending vertically relative to the lower utility pole while the flanges are in contact), but there was a problem that it was difficult or impossible to rotate the upper utility pole that was being grasped with conventional gripping work vehicles.In addition, generally, when erecting utility poles, it is often necessary to align the direction of rotation, and there was also a problem that such adjustment of the direction of rotation was difficult or impossible.

[0005] The present invention has been made in consideration of such problems, and has an object to provide a gripping type work vehicle that can grip a pole-shaped object such as a utility pole and rotate the pole around its central axis. [Means for solving the problem]

[0006] In order to achieve the above-mentioned objective, the grip-type work vehicle of the present invention is configured to include a vehicle body, a boom mounted on the vehicle body so as to be capable of rotating, raising and lowering and extending, a gripping section for gripping a pillar-shaped object, a support mechanism provided between the tip of the boom and the gripping section for changing the attitude of the gripping section relative to the tip of the boom, and a control device for controlling the operation of the boom and the support mechanism. The control device is capable of controlling the horizontal movement of the gripping part by combining control of the boom's rotation, raising and lowering, and extension operation with control of the support mechanism, and the support mechanism has a left-right swivel mechanism for swiveling the gripping part left and right. The control device is capable of controlling the gripping part to swivel using the left-right swivel mechanism while the gripping part is holding a vertically extending pillar-like object, by combining control to rotate the boom and control to move the gripping part in the horizontal forward and backward directions, thereby rotating the pillar-like object held by the gripping part around a central axis extending vertically.

[0007] In the grip-type work vehicle, it is preferable that the control device is capable of controlling the gripping part to swivel using the left and right swivel mechanism while a pillar-shaped object is extended vertically and gripped by the gripping part, controlling the rotation operation of the boom to return the left and right movement of the pillar caused by the left and right swivel operation to its original position, and controlling the gripping part to move in the horizontal forward and backward directions to return the forward and backward movement of the pillar caused by the swivel operation of the gripping part and the rotation operation of the boom to its original position, and rotating the pillar gripped by the gripping part about a vertically extending central axis.

[0008] Another grip-type work vehicle according to the present invention is configured to include a vehicle body, a boom mounted on the vehicle body so as to be capable of rotating, raising and lowering and extending, a gripping section for gripping a pillar-shaped object, a support mechanism provided between the tip of the boom and the gripping section for changing the attitude of the gripping section relative to the tip of the boom, and a control device for controlling the operation of the boom and the support mechanism. The control device is capable of controlling the horizontal movement of the gripping part by combining control of the rotation, raising and lowering and extension operation of the boom with control of the operation of the support mechanism, and the support mechanism has a left-right swivel mechanism which causes the gripping part to swivel left and right, and the control device moves the gripping part horizontally when a pillar-shaped object is extended vertically and gripped by the gripping part so that the left-right swivel center of the gripping part moves along a trajectory that rotates around the vertically extending central axis of the pillar-shaped object gripped by the gripping part, and controls the gripping part to swivel left and right so that the pillar held by the gripping part rotates without moving its central axis, thereby enabling control to rotate the pillar held by the gripping part around its vertically extending central axis.

[0009] In the gripping type work vehicle, the gripping section has a pair of opening and closing gripping claws for gripping a column-shaped object, and the support mechanism has a rotation mechanism for rotating the gripping claws around a rotation axis perpendicular to the opening and closing direction, and it is preferable that the gripping claws can be rotated by the rotation mechanism to adjust the angle at which the column-shaped object gripped by the gripping claws is held. Effect of the Invention

[0010] According to the grip-type work vehicle of the present invention, in a state where a pole-shaped object is vertically extended and gripped by the gripper, the control of swinging the gripper by the left-right swing mechanism, the control of rotating the boom, and the control of moving the gripper in the horizontal forward and backward directions can be combined to rotate the pole-shaped object gripped by the gripper about a vertically extending central axis. Therefore, for example, when an upper utility pole is gripped by the gripping device and a flange at the lower end of the upper utility pole is abutted against and joined to a flange at the upper end of a lower utility pole that has been erected, and the two flanges are bolted together, the upper utility pole can be rotated while being gripped, and an adjustment operation can be performed to align the bolt insertion holes of both flanges. Therefore, the operation of bolting both flanges can be easily performed.

[0011] In the grip-type work vehicle, it is preferable that the control device, in a state where the gripper extends vertically and grips a pole-like object, controls the gripper to swing using the left-right swing mechanism, controls the boom to turn so that the left-right movement of the pole-like object caused by the left-right swing action is returned to its original position, and controls the gripper to move in the horizontal forward and backward directions so that the forward and backward movement of the pole-like object caused by the swing action of the gripper and the swing action of the boom is returned to its original position. By controlling in this way, the upper utility pole can be rotated around the vertical axis without moving the position of the vertical axis while the upper utility pole is being gripped, and the bolt insertion holes of both flanges can be easily aligned with each other. This makes it even easier to bolt the two flanges together.

[0012] According to another gripping type work vehicle of the present invention, in a state where a pole-shaped object is vertically extended and gripped by the gripping part, the gripping part is moved in the horizontal direction so that the left and right swing center of the gripping part moves along a trajectory that rotates around the vertically extending central axis of the pole-shaped object gripped by the gripping part, and the gripping part is controlled to swing left and right so that the pole-shaped object gripped by the gripping part rotates without moving its central axis, and the pole-shaped object gripped by the gripping part can be controlled to rotate around the vertically extending central axis. Therefore, for example, when an upper utility pole is gripped by a gripping device and a flange at the lower end of the upper utility pole is abutted against and joined to a flange at the upper end of a lower utility pole that has been erected, and the two flanges are bolted together, the upper utility pole can be rotated while being gripped, and an adjustment operation can be performed to align the bolt insertion holes of both flanges. Therefore, the operation of bolting both flanges can be easily performed.

[0013] In the gripping type work vehicle, it is further preferable that the gripping claws can be rotated by the rotation mechanism to adjust the angle at which the pole-like object is held by the gripping claws. This allows the angle at which a pole-like object such as a utility pole is held to be adjusted and the pole can be extended vertically and gripped, making it easy to perform pole erection work. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a side view of a gripping-type pole hole digging vehicle which is a specific embodiment of the gripping-type work vehicle according to the present invention. [Diagram 2] FIG. 2 is a plan view of the above-mentioned gripping-type pole hole digging vehicle. [Diagram 3] FIG. 2 is a side view showing the use state of the above-mentioned grip-type hole digging pole construction vehicle. [Figure 4] FIG. 2 is an oblique view of an auger device provided on the above-mentioned grip-type hole digging pole construction vehicle. [Diagram 5] This is an oblique view of a gripping device provided on the above-mentioned gripping-type hole digging pole construction vehicle. [Figure 6] FIG. 2 is a perspective view of a main part of the gripping device as viewed from the right. [Figure 7] FIG. 2 is a perspective view of a main part of the gripping device as viewed from the left. [Figure 8] FIG. 2 is a cross-sectional view of the gripping device. [Figure 9] FIG. 2 is a vertical cross-sectional view of the gripping device. [Figure 10] FIG. 2 is a functional block diagram of the above-mentioned gripping-type pole hole digging vehicle. [Figure 11] FIG. 2 is a plan view showing a state in which a utility pole is gripped by the gripping device. [Figure 12] FIG. 11 is an explanatory diagram illustrating a process of rotating the utility pole gripped by the gripping device. [Figure 13] 11A to 11C are schematic diagrams for explaining an operation of setting a gripping portion of the gripping device in a horizontal position. [Figure 14] 10 is a conceptual diagram for explaining the relationship between a load acting on the gripping portion and the amount of displacement when the gripping portion is moved vertically downward. FIG. [Figure 15] FIG. 2 is a schematic diagram showing the excavation work of the above-mentioned gripping-type hole digging pole construction vehicle. [Figure 16] 1 is a schematic diagram showing the operation of the gripping part when the automatic vertical switch provided on the above-mentioned gripping-type hole digging pole construction vehicle is operated. [Figure 17] 1 is a schematic diagram illustrating the direction of the load acting on the gripping portion during the process of inserting the lower utility pole held by the gripping portion into a pole hole. FIG. [Figure 18] FIG. 13 is a schematic diagram illustrating the process of attaching the upper utility pole held by the holding portion onto an erected lower utility pole. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. First, the overall configuration of a grip-type hole digging pole erection vehicle 1 as a specific embodiment of a grip-type working vehicle according to the present invention will be described with reference to Figs. 1 to 3.

[0016] As shown in Fig. 1, the grip-type post hole digger 1 has a driver's cabin 7 at the front of the vehicle body 2, and is constructed based on a truck vehicle that can run on a pair of left and right tires and wheels 5 arranged at the front and rear of the vehicle body 2. Jacks 9 for lifting and supporting the vehicle body 2 are arranged at four points on the front, rear, left and right of the vehicle body 2. Each jack 9 lifts and supports the vehicle body 2 by driving a jack cylinder (not shown) provided inside it to extend downward, thereby stabilizing the entire vehicle body 2. The jacks 9 are operated by operating a jack operating device (not shown) provided at the rear of the vehicle body 2.

[0017] A swivel base 12 that is driven by a swivel motor 14 (see FIG. 10) and configured to be horizontally rotatable about a vertical axis is provided in a mounting area behind the driver's cabin 7 in the vehicle body 2. The base end of a boom 13 is attached to the swivel base 12 so as to be vertically swingable (raised and lowered).

[0018] The boom 13 has a configuration in which, from the swivel base 12 side, a base end boom 13a, an intermediate boom 13b, and a tip end boom 13c are nested together, and the boom 13 can be extended and retracted in the axial direction (longitudinal direction) by the extension and retraction of a telescopic cylinder 15 (see FIG. 10) provided inside. In addition, a hoisting cylinder 16 is provided between the base end boom 13a and the swivel base 12, and by driving the hoisting cylinder 16 to extend and retract, the entire boom 13 can be raised and lowered in the up-down plane (vertical plane).

[0019] The boom 13 is provided with an auger support 17 that can be selectively connected to the base boom 13a and the tip boom 13c. As shown in FIG. 4, an upper shaft portion 27a of a connecting rod member 27 is pivotally connected to the auger support 17 so as to be swingable in the left-right direction. An auger device 20 for drilling a post hole is pivotally connected to a lower shaft portion 27b of the connecting rod member 27 so as to be swingable in the front-rear direction. The auger device 20 includes an auger motor section 21 pivotally connected to the lower shaft portion 27b of the connecting rod member 27, and an auger screw (earth auger) 25 that is rotated about its axis by operating the auger motor section 21. The auger motor section 21 includes an auger motor 22 that is rotated by hydraulic pressure, an auger reducer 23 connected to the output shaft of the auger motor 22, and an auger housing 24 that houses the auger motor 22 and the auger reducer 23. A drive shaft (not shown) of the auger reducer 23 protrudes from the lower end of the auger housing 24, and an upper end of the auger screw 25 is connected to this drive shaft.

[0020] An auger storage device 18 is disposed on the side of the base boom 13a, which holds the auger device 20 in a stored state with the auger support 17 connected to the base boom 13a. The auger device 20 is attached to the auger support 17 via a connecting rod member 27 so as to be able to swing up and down in a vertical plane, and can be swung between a stored position in which the auger device 20 is stored along the side of the base boom 13a by the auger storage device 18, and a working position in which the auger device 20 is removed from the auger storage device 18 (the auger support 17 is connected to the tip boom 13c) and the auger screw 25 is lowered toward the ground. The auger device 20 can be moved between the working position and the auger support 17. When the auger screw 25 is in this position, the auger screw 25 is suspended from the tip of the boom 13 about both shaft portions 27a, 27b of the connecting rod member 27 as fulcrums so that the auger screw 25 can swing freely in the front-rear and left-right directions, regardless of the position of the boom 13.

[0021] When the auger device 20 is used, as shown in I of FIG. 3, the auger support 17 is connected to the tip boom 13c, and the auger device 20 is swung from the auger storage device 18 to a working position (the auger screw 25 is in a substantially vertical position relative to the ground), and the auger screw 25 is rotated by the rotational drive of the auger motor 22 while the boom 13 is moved downward linearly in conjunction with the lowering and retracting operations, thereby enabling excavation work for a pole hole. On the other hand, when the auger device 20 is not used, as shown in FIGS. 1 and 2, the auger support 17 is connected to the base boom 13a, and the auger device 20 is stored and held by the auger storage device 18 in a storage position along the side of the base boom 13a. When the auger device 20 is in the storage position, various work such as pole erection work, pole removal work, and obstacle relocation work can be performed using the gripping device 50 described later, as shown in II of FIG. 3.

[0022] An arm bracket 19 is fixed to the tip of the tip boom 13c. A gripping device 50 for gripping an object (pillar-shaped object) such as a utility pole or a tree is attached to the arm bracket 19. The configuration of the gripping device 50 will be described with additional reference to Figs. 5 to 9. Note that hatching showing cross sections has been omitted in Figs. 8 and 9 to make the drawings easier to see. For ease of explanation, the directions of the illustrated front-rear, left-right, and up-down arrows will be referred to as the front-rear direction, left-right direction, and up-down direction, respectively, with the attitude of the gripping device 50 shown in Fig. 5 as the reference.

[0023] The gripping device 50 is configured to include an arm 51 attached to the arm bracket 19 so as to be able to swing (bend and extend) in the vertical direction, a first joint member 60 attached to the tip of the arm 51 so as to be able to swing (pivot) in the vertical direction, a second joint member 70 attached to the first joint member 60 so as to be able to swing (pivot) in the left-right direction, and a gripper 80 rotatably attached to the second joint member 70. The posture of a gripping portion 81 of the gripper 80 can be changed by the arm 51, the first joint member 60, the second joint member 70, a vertical swing cylinder 62 described below, a horizontal swing cylinder 71, a gripper motor 79, and the like, and this mechanism is referred to as a support mechanism.

[0024] One axial (longitudinal) end of the arm 51 is pivotally connected to the arm bracket 19 via a connecting pin 52, and the other axial (longitudinal) end is pivotally connected to a first joint member 60 via a connecting pin 53. An arm cylinder 55 is attached between the arm bracket 19 and the first joint member 60. A rod side end of the arm cylinder 55 is pivotally connected to the arm bracket 19 via a connecting pin 56. A bottom side end of the arm cylinder 55 is pivotally connected to the first joint member 60 via a connecting pin 57. By extending and retracting the arm cylinder 55, the arm 51 can be swung (bent and extended) in the up and down direction around the connecting pin 52 relative to the arm bracket 19.

[0025] The first joint member 60 is formed in a bifurcated shape with an open tip, and the second joint member 70 is pivotally connected to both ends of the bifurcated shape via a pair of upper and lower connecting pins 61. A vertical swivel cylinder 62 is provided between the first joint member 60 and the arm 51. The bottom side end of the vertical swivel cylinder 62 is pivotally connected to the base end side of the arm 51 via a connecting pin 63. The rod side end of the vertical swivel cylinder 62 is pivotally connected to the upper end side of the first joint member 60 via a connecting pin 64. By extending and retracting the vertical swivel cylinder 62, the first joint member 60 can be swung up and down (vertical swivel operation) around the connecting pin 53 relative to the arm 51.

[0026] The second joint member 70 is supported so as to be sandwiched from above and below by the first joint member 60. In addition, a horizontal swivel cylinder 71 is provided at the upper end of the first joint member 60. The bottom side end of the horizontal swivel cylinder 71 is pivotally connected to the tip end of the first joint member 60, and the rod side end is pivotally connected to the rear end of the second joint member 70. By extending and contracting the horizontal swivel cylinder 71, the second joint member 70 can be swung left and right relative to the first joint member 60 around the connecting pin 61 (horizontal swivel operation).

[0027] The gripper 80 includes a gripping portion 81 that grips an object, a gripper housing 86 that supports the gripping portion 81 and is rotatably mounted on the second joint member 70, and an opening / closing mechanism 93 that opens and closes the gripping portion 81.

[0028] The gripping portion 81 includes a pair of gripping claws 82 and a pair of upper and lower support plate portions 83 that support the pair of gripping claws 82 so as to be openable and closable in a direction (opening / closing direction) in which the pair of gripping claws 82 approach or move away from each other. The gripping claws 82 can grip various objects (pillar-shaped objects) such as utility poles and trees. The base ends of the gripping claws 82 are pivotally connected to the upper and lower support plate portions 83 via connecting pins 84. Alternating notches 82a and 82b are formed in the tips of the gripping claws 82, so that the tips can cross (overlap) each other. The support plate portion 83 is provided with a flat upper bracket 85 for detachably mounting an attachment (not shown) (for example, a tree felling device for felling trees).

[0029] The gripper housing 86 includes a support tube portion 87 connected to the upper and lower support plate portions 83 and supported rotatably by the second joint member 70, and a cylinder bracket portion 92 fixed to the base end side of the support tube portion 87 and disposed between the first joint member 60 and the second joint member 70.

[0030] The support cylinder 87 has a double structure including an inner cylinder 88 formed in a hollow rectangular cylinder shape and an outer cylinder 89 formed in a hollow cylindrical shape provided on the outer periphery of the inner cylinder 88. A sliding member 95 of an opening / closing mechanism 93 described later is attached to the inner periphery of the inner cylinder 88 so as to be slidable in the front-rear direction. A worm wheel 90 is attached to the outer periphery of the outer cylinder 89 so as to be concentric with the outer cylinder 89. The worm wheel 90 is engaged with a worm pinion 91 supported rotatably inside the second joint member 70. A gripper motor 79 is attached to the upper end of the second joint member 70, and the worm pinion 91 is connected to the output shaft of the gripper motor 79 via a reducer. When the gripper motor 79 is rotated in the forward direction, the entire gripper 80 rotates in a predetermined direction around the rotation axis X (see FIG. 8) via the worm pinion 91 and the worm wheel 90. On the other hand, when the gripper motor 79 is rotated in the reverse direction, the entire gripper 80 rotates in the opposite direction to the predetermined direction around the rotation axis X (see FIG. 8) via the worm pinion 91 and the worm wheel 90. In the posture of the gripping device 50 shown in FIG. 5, the direction of the rotation axis X of the gripper 80 (gripping portion 81) corresponds to the front-rear direction, and the opening / closing direction (gripping direction) of the gripping portion 81 corresponds to the left-right direction.

[0031] The opening / closing mechanism 93 includes a pair of link members 94, a sliding member 95 linked and connected to the pair of link members 94, and a gripper cylinder 99 that slides the sliding member 95 back and forth. One end of each link member 94 is pivotally connected to the middle part of the gripping claw 81 via a connecting pin 96. The pair of link members 94 are pivotally connected to the tip part of the sliding member 95 via a connecting pin 97 with the other ends of each link member 94 stacked vertically. The sliding member 95 is inserted into the hollow part of the inner cylindrical portion 88 and is attached so as to be slidable (reciprocating) along the inner peripheral surface of the inner cylindrical portion 88. Between the outer peripheral surface of the sliding member 95 and the inner peripheral surface of the inner cylindrical portion 88, A slider 98 made of synthetic resin is attached to guide the sliding (reciprocating movement) of the sliding member 95. A rod side end of a gripper cylinder 99 is connected to a base end of the sliding member 95. A bottom side end of the gripper cylinder 99 is connected to the cylinder bracket portion 92 of the gripper housing 86.

[0032] When the gripper cylinder 99 is extended, the sliding member 95 slides in the extension direction, and the link members 94 swing in a direction away from each other. As a result, the gripping claws 82 swing in the opening direction with the connecting pin 84 as a fulcrum (the gripping claws 82 operate in the opening direction (opening operation)), thereby enabling the gripping of the object to be released. On the other hand, when the gripper cylinder 99 is contracted, the sliding member 95 slides in the contraction direction, and the link members 94 swing in a direction approaching each other. As a result, the gripping claws 82 swing in the closing direction with the connecting pin 84 as a fulcrum (the gripping claws 82 operate in the closing direction (closing operation)), thereby enabling the object to be gripped. The opening / closing mechanism 93 is configured symmetrically, so that the pair of gripping claws 82 are opened and closed symmetrically.

[0033] An operator's seat 30 for operating each of the working devices (the swivel base 12, the boom 13, the auger device 20, and the gripping device 50) is provided on the side of the swivel base 12 of the vehicle body 2. In front of the operator's seat 30, an operating device 31 is provided that can be operated by an operator while in a seated position. The operating device 31 is provided with a boom rotation and hoisting operation lever 32a which is operated to rotate and raise the boom 13, an extension / retraction operation lever 32b which is operated to extend and retract the boom 13 and bend and extend the arm 51, an auger operation lever 32c which is operated to rotate the auger screw 25, a gripper vertical swing operation lever 32d which is operated to swing the gripper 81 vertically, a gripper horizontal swing operation lever 32e which is operated to swing the gripper 81 horizontally, a gripper rotation operation lever 32f which is operated to rotate the gripper 81, and a gripper opening / closing operation lever 32g which is operated to open and close the gripper 81 (see Figure 10).

[0034] The operating device 31 is further provided with a mode selection switch 33 and an automatic vertical switch 34, as shown in Fig. 10. The mode selection switch 33 is a switch that can be switched to any one of a normal operation mode position, an auger vertical movement mode position, a gripper horizontal / vertical movement mode position, and a gripped object rotational movement mode position, and sends a command signal according to the position to the controller 100. A detailed explanation of the specific operation control in each mode will be given later, but when the mode selection switch 33 is set to the normal operation mode position and in the normal operation mode state, control is performed to operate the corresponding actuator in response to the operation of each operating lever. Specifically, the drive of each actuator is controlled so that the boom 13 is rotated and hoisted in response to operation of the boom rotation / hoisting operation lever 32a, the boom 13 is extended and retracted and the arm 51 is flexed in response to operation of the boom extension / retraction operation lever 32b, the auger screw 25 is rotated in response to operation of the auger operation lever 32c, the gripper part 81 is swung vertically in response to operation of the gripper part vertical swing operation lever 32d, the gripper part 81 is swung horizontally in response to operation of the gripper part horizontal swing operation lever 32e, the gripper part 81 is rotated in response to operation of the gripper part rotation operation lever 32f, and the gripper part 81 is opened and closed in response to operation of the gripper part opening / closing operation lever 32g.

[0035] When the mode selection switch 33 is set to the auger vertical movement mode position and the auger vertical movement mode is active, the boom rotation and hoisting control lever 32a functions as an auger vertical movement control lever. Specifically, when the boom rotation and hoisting control lever 32a is tilted forward, the auger screw 25 (the tip of the boom 13) is controlled to move vertically downward, and when the boom rotation and hoisting control lever 32a is tilted backward (toward the user), the auger screw 25 (the tip of the boom 13) is controlled to move vertically upward.

[0036] When the mode selection switch 33 is set to the gripper horizontal / vertical movement mode position and the gripper horizontal / vertical movement mode is in effect, the boom slewing / hoisting operation lever 32a functions as a vertical movement operation lever, and the boom telescopic / flexing operation lever 32b functions as a horizontal movement operation lever. Specifically, when the boom slewing / hoisting operation lever 32a is tilted forward, control is performed to move the gripper 80 (grip 81) vertically downward, and when the boom slewing / hoisting operation lever 32a is tilted backward (toward the user), control is performed to move the gripper 80 (grip 81) vertically upward. When the boom telescopic / flexing operation lever 32b is tilted left or right, control is performed to move the gripper 80 (grip 81) horizontally left or right, and when the boom telescopic / flexing operation lever 32b is tilted forward or backward, control is performed to move the gripper 80 (grip 81) horizontally forward or backward.

[0037] When the mode selection switch 33 is set to the gripped object rotational movement mode position and the gripped object rotational movement mode is in effect, the boom slewing and hoisting operation lever 32a functions as a rotational movement operation lever. When the boom slewing and hoisting operation lever 32a is tilted to the left or right, the pillar is supported by the gripping portion 81 of the gripper 80 in a state in which it extends vertically, and the pillar is controlled to rotate about its vertical central axis while the vertical central axis of the pillar remains unchanged. For example, when the boom slewing and hoisting operation lever 32a is tilted to the right, the pillar is controlled to rotate in a clockwise direction, and when the boom slewing and hoisting operation lever 32a is tilted to the left, the pillar is controlled to rotate in a counterclockwise direction.

[0038] Automatic vertical switch 34 is configured as a toggle switch that can be switched between an ON position and an OFF position (so that the switched operating position is maintained even if the operator releases his / her hand). When automatic vertical switch 34 is selected to the ON position, as will be described later in detail, vertical oscillating cylinder 62 and gripper motor 79 are operated to vertically oscillate and rotate gripper 81, thereby making gripper 81 assume a horizontal position (i.e., a utility pole or the like held by gripper 81 can be held so as to extend vertically). Note that automatic vertical switch 34 is enabled (operation signal is enabled) when the inclination angle of gripper 81 with respect to the horizontal plane detected by gripper inclination angle detector 124 (see FIG. 10) described later is within a predetermined angle.

[0039] Here, as shown in FIG. 10, the operating mechanisms for the swivel base 12, boom 13, auger device 20, gripping device 50, etc., include a controller 100 that receives operation signals from an operating device 31 and controls the swivel motor 14, telescopic cylinder 15, hoisting cylinder 16, auger motor 22, arm cylinder 55, vertical swing cylinder 62, horizontal swing cylinder 71, gripper motor 79, and gripper cylinder 99 (hereinafter collectively referred to as "hydraulic actuators"), and a hydraulic unit 110 that supplies hydraulic oil to drive the hydraulic actuators.

[0040] An operation signal output by operating the operating device 31 is input to the controller 100. The controller 100 outputs a command signal corresponding to the operation signal to the hydraulic unit 110 (control valve 112).

[0041] The hydraulic unit 110 is configured to have a hydraulic pump 111 that discharges hydraulic oil, and a control valve 112 that controls the supply direction and supply amount of hydraulic oil supplied from the hydraulic pump 111 to each hydraulic actuator. The hydraulic pump 111 is driven by power taken from the vehicle engine via a PTO mechanism (not shown). The control valves 112 include an electromagnetic proportional control valve V1 corresponding to the swing motor 14, an electromagnetic proportional control valve V2 for controlling the operation of the telescopic cylinder 15, an electromagnetic proportional control valve V3 for controlling the operation of the hoisting cylinder 16, an electromagnetic proportional control valve V4 for controlling the operation of the auger motor 22, an electromagnetic proportional control valve V5 for controlling the operation of the arm cylinder 55, an electromagnetic proportional control valve V6 for controlling the operation of the vertical swing cylinder 62, an electromagnetic proportional control valve V7 for controlling the operation of the horizontal swing cylinder 63, and an electromagnetic proportional control valve V8 for controlling the operation of the vertical swing cylinder 64. The control valve 112 has an electromagnetic proportional control valve V7 for controlling the operation of the gripper 71, an electromagnetic proportional control valve V8 for controlling the operation of the gripper motor 79, and an electromagnetic proportional control valve V9 for controlling the operation of the gripper cylinder 99. Based on a command signal from the controller 100, the control valve 112 electromagnetically controls the opening of each of the electromagnetic proportional control valves V1 to V9 to control the supply direction and supply amount of hydraulic oil supplied from the hydraulic pump 111 to each hydraulic actuator, and controls the operation direction and operation speed of each hydraulic actuator (controlling the operation direction and operation speed of the swivel base 12, the boom 13, the auger device 20, and the gripping device 50).

[0042] The controller 100 is electrically connected to various detectors such as a boom hoisting angle detector 120, a boom extension amount detector 121, a boom rotation angle detector 122, an auger inclination angle detector 123, a gripper inclination angle detector 124, a gripper load detector 125, and a gripper cylinder pressure detector 126.

[0043] The boom hoisting angle detector 120 is provided inside the base end boom 13a and detects the hoisting angle of the boom 13. The boom extension amount detector 121 is provided at the base end of the base end boom 13a and detects the length (extension amount) of the boom 13. The boom rotation angle detector 122 is provided on the vehicle body 2 and detects the rotation angle of the boom 13 (rotating body 12).

[0044] The auger inclination angle detector 123 is attached to the upper part of the auger motor unit 21 (auger housing 24). The auger inclination angle detector 123 detects the inclination angle of the auger device 20 (auger screw 25). As described above, the auger device 20 is suspended from the tip of the boom 13 around both shafts 27a, 27b of the connecting rod member 27 as fulcrums so that the auger screw 25 assumes a vertical position along the direction of gravity (vertical direction) regardless of the position of the boom 13. Therefore, when the auger device 20 is excavating a post hole (indicated by the symbol "K" in FIG. 15) and the excavation resistance of the ground is large, the axis of the auger screw 25 may incline in the front-rear and left-right directions with respect to the vertical line (vertical direction). The auger inclination angle detector 123 is configured as a two-axis inclination angle detector that detects the left-right inclination angle and the front-back inclination angle of the auger screw 25 as the inclination angle of the auger screw 25 with respect to the vertical direction. The auger inclination angle detector 123 detects the left-right inclination angle and the front-back inclination angle of the auger screw 25, and outputs a voltage signal (detection signal) corresponding to the detected inclination angle to the controller 100.

[0045] The gripper inclination angle detector 124 is attached to the upper surface of the gripper 81 (support plate 83). The gripper inclination angle detector 124 is a two-axis inclination angle detector that detects the inclination angle in the left-right direction and the inclination angle in the front-rear direction as the inclination angle of the gripper 81 with respect to the horizontal plane. The gripper inclination angle detector 124 detects the inclination angle in the left-right direction and the inclination angle in the front-rear direction of the gripper 81, and outputs a voltage signal (detection signal) according to the detected inclination angle to the controller 100. The gripper inclination angle detector 124 further detects the up-down swing angle of the arm 51 with respect to the tip of the boom 13. For this reason, the gripper inclination angle detector 124 may detect the inclination angle in the left-right direction and the inclination angle in the front-rear direction with respect to the tip of the arm 51, instead of detecting the inclination angle of the gripper 81 with respect to the horizontal plane.

[0046] The gripper load detector 125 is a so-called pin-type load cell, and is configured as the above-mentioned connecting pin 63 that pivotally connects the bottom end of the vertical swing cylinder 62 and the base end of the arm 51. The gripper load detector 125 detects the load acting in the axial direction (axial direction of the vertical swing cylinder 62) from the vertical swing cylinder 62 to the connecting pin 63, and outputs a voltage signal (detection signal) corresponding to the detected load to the controller 100. Note that the load detected by the gripper load detector 125 (load acting on the connecting pin 62) is proportional to the load acting on the gripper 81 (load that the gripper 81 receives in a vertical plane). Therefore, detailed description will be given below. As will be described later, the controller 100 determines the load acting on the grip portion 81 based on the load detected by the grip portion load detector 125 .

[0047] The gripper cylinder pressure detector 126 is provided in an oil passage connecting the electromagnetic proportional control valve V9 and the rod side oil chamber of the gripper cylinder 99, and detects the pressure of the hydraulic oil supplied to the rod side oil chamber of the gripper cylinder 99 (the pressure of the rod side oil chamber). The gripper cylinder pressure detector 126 detects the pressure of the rod side oil chamber of the gripper cylinder 99, and outputs a voltage signal (detection signal) corresponding to the detected pressure to the controller 100. The pressure detected by the gripper cylinder pressure detector 126 is proportional to the gripping force of the gripper 81 (the force with which the gripper 81 grips an object). Therefore, as will be described in detail later, the controller 100 determines the gripping force of the gripper 81 based on the pressure detected by the gripper cylinder pressure detector 126.

[0048] The controller 100 includes a position calculation unit 101, an operation control unit 102, an auger inclination determination unit 103, a grip determination unit 104, an automatic vertical / horizontal control unit 105, and a load determination unit 106.

[0049] The position calculation unit 101 calculates the position of the tip of the boom 13 relative to the vehicle body 2 based on detection information from the boom hoisting angle detector 120, the boom extension amount detector 121, and the boom rotation angle detector 122. The position calculation unit 101 further calculates the position of the gripping part 81 relative to the tip of the boom 13 (relative to the vehicle body 2) based on detection information from a gripping part inclination angle detector 124 in addition to these detection information.

[0050] The operation control unit 102 controls the operation of each actuator according to an operation signal (operation command) output from the operation device 31, based on a mode (normal operation mode, auger vertical movement mode, gripper horizontal / vertical movement mode, gripped object rotational movement mode) selected by the mode selection switch 33. Each mode will be described below.

[0051] (Normal operation mode) When the mode selection switch 33 is set to the normal operation mode and the operation levers 32a-32g are operated, the operation control section 102 independently operates each of the hydraulic actuators in response to the operation of each of the operation levers 32a-32g. Specifically, when the boom rotation / hoisting operation lever 32a is tilted forward (in the front-rear and left-right directions based on the operator operating the boom: the same applies below), the hoisting cylinder 16 is contracted to lower the boom 13, and when the boom rotation / hoisting operation lever 32a is tilted backward, the hoisting cylinder 16 is extended to raise the boom 13. When the boom telescopic / flexible / extendable operation lever 32b is tilted forward, the telescopic cylinder 15 is extended to extend the boom 13, and when the boom telescopic / flexible / extendable operation lever 32b is tilted backward, the telescopic cylinder 15 is contracted to retract the boom 13. When the boom rotation / hoisting operation lever 32a is tilted to the left, the rotation motor 14 is rotated in the forward direction to rotate the boom 13 in the counterclockwise direction, and when the boom rotation / hoisting operation lever 32a is tilted to the right, the rotation motor 14 is rotated in the reverse direction to rotate the boom 13 in the clockwise direction.

[0052] When the auger device 20 is used, when the auger operating lever 32c is tilted forward, the auger motor 22 is operated to rotate in reverse and the auger screw 25 is rotated in the reverse direction, and when the auger operating lever 32c is tilted backward, the auger motor 22 is operated to rotate in forward and the auger screw 25 is rotated in the forward direction.

[0053] When the gripping device 50 is used, when the boom telescopic bending / extending operation lever 32b is tilted leftward, the arm 51 is bent and extended downward relative to the tip of the boom 13, When the telescopic bending / extending operation lever 32b is tilted to the right, the arm 51 is bent and extended upward relative to the tip of the boom 13. When the gripper vertical swing operation lever 32d is tilted forward, the vertical swing cylinder 62 is extended to swing the gripper 81 downward (vertical swing), and when the gripper vertical swing operation lever 32d is tilted backward, the vertical swing cylinder 62 is contracted to swing the gripper 81 upward (vertical swing). When the gripper horizontal swing operation lever 32e is tilted to the left, the horizontal swing cylinder 71 is extended to swing the gripper 81 to the left (horizontal swing), and when the gripper vertical swing operation lever 32e is tilted to the right, the horizontal swing cylinder 71 is contracted to swing the gripper 81 to the right (horizontal swing). When the gripper rotation operation lever 32f is tilted forward, the gripper motor 79 is operated to rotate in the forward direction and rotate the gripper 81 in the clockwise direction, and when the gripper rotation operation lever 32f is tilted backward, the gripper motor 79 is operated to rotate in the reverse direction and rotate the gripper 81 in the counterclockwise direction. When the gripper opening / closing operation lever 32g is tilted forward, the gripper cylinder 99 is contracted and the gripper 81 is operated in the closing direction (direction to grip the target object), and when the gripper opening / closing operation lever 32g is tilted backward, the gripper cylinder 99 is extended and the gripper 81 is operated in the opening direction (direction to release the grip of the target object).

[0054] (Auger vertical movement mode) When the mode selection switch 33 is set to the auger vertical movement mode position and the boom rotation / hoisting operation lever 32a is operated, the operation control unit 102 combines and links the telescopic operation of the hoisting cylinder 16 and the telescopic operation of the telescopic cylinder 15 based on the position information (current position) of the tip of the boom 13 calculated by the position calculation unit 101, and moves the auger screw 25 (tip of the boom 13) in the vertical direction in response to the operation of the boom rotation / hoisting operation lever 32a. Specifically, when the boom rotation / hoisting operation lever 32a is tilted forward, the auger screw 25 is moved vertically downward by combining the retraction of the hoisting cylinder 16 and the retraction of the telescopic cylinder 15, and when the boom rotation / hoisting operation lever 32a is tilted backward, the auger screw 25 is moved vertically upward by combining the extension of the hoisting cylinder 16 and the extension of the telescopic cylinder 15.

[0055] (Handle horizontal and vertical movement mode) When the gripper horizontal / vertical movement mode is selected by the mode selection switch 33, the boom rotation / hoisting operation lever 32a functions as a vertical movement operation lever as described above. When the gripper horizontal / vertical movement mode is selected and the boom rotation / hoisting operation lever 32a is operated, the operation control unit 102 operates a combination of the telescopic operation of the hoisting cylinder 16, the telescopic operation of the telescopic cylinder 15, and the telescopic operation of the vertical swing cylinder 62 based on the position information (current position) of the tip of the boom 13 calculated by the position calculation unit 101 and the tilt angle of the gripper 81 detected by the gripper tilt angle detector 124, and moves the gripper 81 (object gripped by the gripper 81) in the vertical direction in response to the operation of the boom rotation / hoisting operation lever 32a.

[0056] Specifically, when the boom rotation hoisting operation lever 32a is tilted forward, the gripper 81 moves vertically downward by combining the retraction of the hoisting cylinder 16, the retraction of the telescopic cylinder 15, and the retraction of the vertical swing cylinder 62, and when the boom rotation hoisting operation lever 32a is tilted backward, the gripper 81 moves vertically upward by combining the extension of the hoisting cylinder 16, the extension of the telescopic cylinder 15, and the extension of the vertical swing cylinder 62. The vertical operation control of the gripper 81 is based on position information of the tip of the boom 13 calculated by the position calculation unit 101, and is carried out by controlling the gripper 81, which is connected to the tip of the boom 13 via the arm 51, to move in the vertical direction by combining the extension and contraction of the hoisting cylinder 16 and the extension and contraction of the telescopic cylinder 15, and The control is executed by combining the control of maintaining the gripper 81 (rotation axis X of the gripper 81) in a horizontal state by the extension and retraction of the vertical swing cylinder 62. Note that, instead of the control of maintaining the gripper 81 (rotation axis X of the gripper 81) in a horizontal state by the extension and retraction of the arm cylinder 55, the arm 51 may be swung up and down to maintain the gripper 81 (rotation axis X of the gripper 81) in a horizontal state.

[0057] When the gripper horizontal / vertical movement mode is selected by the mode selection switch 33, the boom telescopic / flexible / extension operation lever 32b also functions as a horizontal movement operation lever as described above. When the boom telescopic / flexible / extension operation lever 32b is operated while the gripper horizontal / vertical movement mode is selected, the operation control unit 102 operates the rotation operation of the swing motor 14, the telescopic operation of the hoisting cylinder 16, the telescopic operation of the telescopic cylinder 15, the telescopic operation of the arm cylinder 55, and the telescopic operation of the vertical swing cylinder 62 in combination based on the position information (current position) of the tip of the boom 13 and the position information (current position) of the grip center of the gripper 81 calculated by the position calculation unit 101, and the tilt angle of the gripper 81 detected by the gripper tilt angle detector 124, to move the gripper 81 (the object gripped by the gripper 81) in the horizontal direction (front-back and left-right directions) in accordance with the operation of the boom telescopic / flexible / extension operation lever 32b. Specifically, when the boom telescopic bending / extension operation lever 32b is tilted left or right, the gripping portion 81 is controlled to move horizontally left and right, and when the boom telescopic bending / extension operation lever 32b is tilted forward or backward, the gripping portion 81 is controlled to move horizontally forward or backward.

[0058] (Object rotation movement mode) When the gripped object rotational movement mode is selected by the mode selection switch 33, the boom slewing / hoisting operation lever 32a functions as a rotational movement operation lever as described above. When the boom slewing / hoisting operation lever 32a is tilted to the left or right, the columnar object is supported by the gripping portion 81 of the gripper 80 in a vertically extending state, and the columnar object is controlled to rotate around the vertical central axis of the columnar object while the vertical central axis of the columnar object remains unchanged. For example, when the boom slewing / hoisting operation lever 32a is tilted to the right, the columnar object is controlled to rotate in a clockwise direction, and when the boom slewing / hoisting operation lever 32a is tilted to the left, the columnar object is controlled to rotate in a counterclockwise direction. There are two types of control for such rotational movement, which will be specifically described below as a first gripped object rotational movement mode control and a second gripped object rotational movement mode control.

[0059] (First gripped object rotation movement mode) FIG. 11 shows a schematic diagram of the tip of the gripping device 50 attached to the arm bracket 19 fixed to the tip boom 13c. A first joint member 60 is attached to the tip of the arm 51 so as to be able to swing vertically about a vertical swing axis O51 (the central axis of the connecting pin 53), a second joint member 70 is attached to the first joint member 60 so as to be able to swing horizontally about a horizontal swing axis O52 (the central axis of the connecting pin 61), and a gripper 80 is attached to the second joint member 70. A pair of left and right gripping claws 82, 82 of the gripper 80 that can be opened and closed can grip a utility pole or the like, and FIG. 11 shows a state in which a utility pole P is gripped. The control of rotating the utility pole P by the gripping device 50 while maintaining the center O11 as it is will be described with reference to FIG. 12.

[0060] The control in the first gripped object rotation movement mode is a combination of a control for performing a lateral swing operation (operation in the direction of arrow A in FIG. 11) of the second joint member 70 about the lateral swing axis O52 while the electric pole P is being gripped by the gripping claws 82, 82 of the gripper 80, an operation control for rotating the swivel base 12 to rotate the boom 13 and the gripping device 50 (operation in the direction of arrow B in FIG. 11), and a horizontal movement operation control for moving the gripper 81 (and the electric pole P gripped by the gripper 81) in the horizontal direction (forward and backward directions) (the same operation as the operation in the gripper horizontal and vertical movement mode). The order of these three operations may be any order, and the three operations may be performed simultaneously. To make the explanation of this operation control easier to understand, an example will be explained in which the second joint member 70 is first operated to swing sideways, then the swivel base 12 is operated to rotate, causing the boom 13 and the gripping device 50 to rotate, and further the gripping part 81 (and the utility pole P gripped by the gripping part 81) is controlled to move horizontally forward.

[0061] When the boom swing / hoisting operation lever 32a is tilted to the left, the second joint member 70 is operated to swing leftward, and the gripper 80 gripping the utility pole P with the gripping claws 82, 82 is also operated to swing leftward. Therefore, as shown in FIG. 12(A), the center O11 of the utility pole P gripped by the gripping claws 82, 82 rotates around the swing axis O52 to the center O12 (this rotation angle is α). Due to this rotation, the utility pole P rotates (rotates on its axis) by an angle α. Next, the rotating base 12 is rotated rightward to match the center of the utility pole P with the line (X1 line) extending in the front-rear direction of the columnar object passing through the original center position O11 (this rotation angle of the rotating base 12 is called γ. Note that gamma is not shown). At this time, the center position becomes the center position O13 as shown in FIG. 12(B), but the utility pole P remains rotated (rotates on its axis) by approximately the angle α. To be precise, the rotation angle returns by an angle γ about the center of rotation of the rotating platform 12, so that the pole remains rotated (rotated) by an angle (α-γ), but this angle γ is much smaller than the angle α, so it is called the angle α. Then, the gripper 81 (and the pole P gripped by the gripper 81) is controlled to move forward in the horizontal direction, so that the center position O14 coincides with the original center position O11. As a result, the pole P gripped by the gripping claws 82, 82 returns to its original position, but is rotated by approximately the angle α. The magnitude of this angle α is determined according to the amount of operation of the second joint member 70 to swing leftward to swing the gripper 80 gripping the pole P. For this reason, for example, if the amount of swing operation is controlled according to the amount of operation of the boom swing / hoisting operation lever 32a, the magnitude of the rotation angle α can be set according to the amount of lever operation.

[0062] (Second gripped object rotation movement mode) The control in the second gripped object rotation movement mode is performed by combining a horizontal movement operation control for moving the gripping portion 81 (and the utility pole P gripped by the gripping portion 81) in the horizontal direction while the utility pole P is gripped by the gripping claws 82, 82 of the gripper 80, and a control for performing a horizontal swing operation (operation in the direction of arrow A) of the second joint member 70 about the horizontal swing axis O52. The order of these two operations may be any order, and the two operations may be performed simultaneously.

[0063] With the utility pole P gripped by the gripping claws 82, 82 of the gripper 80, horizontal movement operation control for moving the gripping part 81 (and the utility pole P gripped by the gripping part 81) in the horizontal direction is performed by combining front-back and left-right movement control. Specifically, as shown by arrow C in FIG. 11, this is control for moving the gripping part 81 horizontally so that the horizontal swing axis O52 moves along an arc C centered on the central axis O11 of the gripped utility pole P. When moving along the arc C in this way, control is also performed for swinging the second joint member 70 horizontally (operating in the direction of arrow A) around the horizontal swing axis O52 so that the center O11 of the gripped utility pole does not move. As a result, the utility pole P gripped by the gripping claws 82, 82 is rotated by an angle β as shown in the figure, without changing its central position O11.

[0064] In the second gripped object rotation movement mode, when the boom rotation / hoisting operation lever 32a is tilted leftward, the gripping portion 81 is controlled to move horizontally leftward so that the lateral swing axis O52 moves along an arc C centered on the central axis O11 of the utility pole P. At the same time, the second joint member 70 is controlled to swing laterally (in the direction of arrow A) around the lateral swing axis O52 so that the center O11 of the gripped utility pole does not move. This allows the utility pole P gripped by the gripping claws 82, 82 to rotate left without changing the central position O11. Similarly, when the boom rotation / hoisting operation lever 32a is tilted rightward, The utility pole P gripped by the gripping claws 82, 82 can be rotated to the right without changing its center position O11.

[0065] Since the control in each mode selected by the operation control section 102 of the controller 100 has been described above, other configurations of the controller 100 will be described below. The auger inclination determination section 103 determines the attitude of the auger device 20 (auger screw 25) based on detection information from the auger inclination angle detector 123. Specifically, the auger inclination determination section 103 compares the inclination angle of the auger screw 25 detected by the auger inclination angle detector 123 with a preset allowable angle (threshold angle) to determine whether the inclination angle of the auger screw 25 exceeds the allowable angle. The inclination angle of the auger screw 25 is the angle at which the axis of the auger screw 25 is inclined forward, backward, left, or right with respect to the vertical direction. The allowable angle is set to, for example, 5 degrees (however, the setting can be changed arbitrarily).

[0066] When the auger inclination determination unit 103 determines that the inclination angle of the auger screw 25 is within the allowable angle during an excavation operation that combines the rotational operation and vertical lowering operation of the auger screw 25 in the auger vertical movement mode, the auger inclination determination unit 103 permits the excavation operation, and when the auger inclination determination unit 103 determines that the inclination angle of the auger screw 25 exceeds the allowable angle, the auger inclination determination unit 103 outputs a restriction signal to the operation control unit 102 to restrict the excavation operation. When the operation control unit 102 receives a restriction signal from the auger inclination determination unit 103, the operation control unit 102 cuts off a control signal for rotating and vertically lowering the auger screw 25 (vertically lowering operation) out of the control signals from the operation control unit 102 to the control valve 112, thereby forcibly stopping the excavation operation of the auger screw 25. This makes it possible to prevent the auger screw 25 from performing an excavation operation in an inclined position that exceeds the allowable angle (the formation of an inclined post hole). At this time, the excavation operation of the auger screw 25 (the rotation operation and vertical lowering operation of the auger screw 25) is restricted, but the operation of moving the auger screw 25 vertically upward from the post hole being excavated (the vertical ascent operation of the auger screw 25) is permitted. Therefore, when the excavation operation of the auger screw 25 is restricted, the auger screw 25 can be returned to a vertical position (a position facing vertically downward) by its own weight by moving the auger screw 25 vertically upward and pulling it out of the excavated hole once. After returning the auger screw 25 to the vertical position in this way, the auger screw 25 can be rotated and vertically lowered again to re-dig the post hole being excavated (the same post hole) from the middle.

[0067] The grip determination unit 104 determines the gripping state of the gripper 81 based on detection information from the gripper cylinder pressure detector 126. Specifically, when the pressure detected by the gripper cylinder pressure detector 126 rises to a preset first threshold pressure or higher, the grip determination unit 104 determines that the gripper 81 is gripping the utility pole (target object) (the gripper 81 is gripping the utility pole with a specified gripping force). In addition, when the pressure detected by the gripper cylinder pressure detector 126 falls to a preset second threshold pressure or lower (wherein the first threshold pressure>the second threshold pressure), the grip determination unit 104 determines that the grip of the utility pole (target object) by the gripper 81 has loosened (the gripping force has been weakened to such an extent that the utility pole does not fall off the gripper 81).

[0068] When automatic vertical switch 34 of operating device 31 is turned on, automatic vertical control unit 105 determines whether the tilt angle of grip unit 81 detected by grip unit tilt angle detector 124 is within a predetermined angle (for example, within 5 degrees). Here, automatic vertical control unit 105 stores an automatic vertical program, and if it determines that the tilt angle of grip unit 81 is within the predetermined angle when an operation signal is input from automatic vertical switch 34, it outputs a command signal to operation control unit 102 based on the detection information from grip unit tilt angle detector 124 in accordance with the automatic vertical program. Upon receiving the command signal from automatic vertical control unit 105, operation control unit 102 feeds back the tilt angle of grip unit 81 from grip unit tilt angle detector 124, Based on the checked information, the vertical swivel cylinder 62 is operated to extend and retract until the forward / backward tilt angle of the gripping portion 81 reaches the target angle (0 degrees), thereby correcting the forward / backward tilt of the gripping portion 81, and the gripper motor 79 is operated to rotate until the left / right tilt angle of the gripping portion 81 reaches the target angle (0 degrees), thereby correcting the left / right tilt of the gripping portion 81.

[0069] Regarding the tilt of the gripper 81 in the front-rear direction, the gripper 81 can be tilted downward (see the Y1 direction in FIG. 13) by extending the vertical swing cylinder 62, and can be tilted upward (see the Y2 direction in FIG. 13) by contracting the vertical swing cylinder 62. Regarding the tilt of the gripper 81 in the left-right direction, the gripper 81 can be tilted leftward (see the Z1 direction in FIG. 13) around the rotation axis X by rotating the gripper motor 79 forward, and can be tilted rightward (see the Z2 direction in FIG. 13) around the rotation axis X by rotating the gripper motor 79 backward. In this way, the operation control unit 102 executes feedback control based on the deviation between the tilt angle of the gripper 81 and the target angle (0 degrees) based on a command from the automatic vertical control unit 105, and sets the gripper 81 in a horizontal position (the utility pole gripped by the gripper 81 in a vertical position). The automatic vertical control is used not only when gripping unit 81 is placed in a horizontal position while gripping a utility pole (i.e., when gripping unit 81 is placed in a vertical position for the utility pole it grips), but also when gripping unit 81 is placed in a horizontal position while not gripping a utility pole (when gripping unit 81 is not gripping anything).As a variation of this, automatic vertical control unit 105 may be configured to perform automatic vertical control only when grip determination unit 104 has determined that gripping unit 81 is gripping a utility pole (target object).

[0070] The load determination unit 106 determines a change in the load acting on the gripping unit 81 based on the detection information from the gripping unit load detector 125. Here, FIG. 14 is a conceptual diagram (graph) showing the relationship between the load acting on the gripping unit 81 and the displacement when the gripping unit 81 is moved vertically downward. As shown in FIG. 14, when the gripping unit 81 is gripping a utility pole, a load according to the weight of the utility pole acts downward on the gripping unit (A in the figure). At this time, when the gripping unit 81 is moved vertically downward and the lower end of the utility pole gripped by the gripping unit 81 reaches the bottom of the pole hole (B in the figure), the load acting on the gripping unit 81 decreases due to the reaction force received from the bottom of the hole (the reaction force trying to push up the utility pole). Then, after the load acting on the gripping unit 81 decreases to 0 (C in the figure), the direction of the load is reversed from the downward direction to the upward direction (D in the figure). In this way, the timing when the utility pole abuts against the bottom of the hole corresponds to the timing when the direction of the load acting on the gripping portion 81 is reversed (the timing when the load becomes 0). Therefore, when the load of the gripping portion 81 detected by the gripping portion load detector 125 during the vertical descent operation of the gripping portion 81 while the gripping portion 81 is gripping a utility pole drops to a threshold load ("0" in this embodiment), the load determination portion 106 determines that the utility pole gripped by the gripping portion 81 has abutted against the bottom of the pole hole.

[0071] When the load determination unit 106 determines that the load detected by the gripper load detector 125 has fallen to the threshold load (the target object has come into contact with the bottom of the pole hole), it outputs a restriction signal to the operation control unit 102 to restrict the vertical descent operation (vertical descent operation) of the gripper 81. When the operation control unit 102 receives a restriction signal from the load determination unit 106, it ignores an operation signal for vertically lowering the gripper 81 among the operation signals input by operating the operating device 31, or blocks a control signal for vertically lowering the gripper 81 among the control signals from the operation control unit 102 to the control valve 112, thereby forcibly stopping the vertical descent operation of the gripper 81 that had been performed up until that point. As a result, even if an operation to move the gripper 81 vertically downward (an operation to move the utility pole downward) is performed any further, the vertical downward movement of the gripper 81 is restricted. In this way, the downward movement of the gripping portion 81 is restricted when the lower end of the utility pole abuts against the bottom (rear end) of the pole hole, thereby preventing the lower end of the utility pole from being pressed excessively against the bottom of the hole.

[0072] Next, the pole erection work using the grip-type hole digging pole erection vehicle 1 of this embodiment will be described using the pole erection work of a utility pole called a flanged split pole as an example. Below, the excavation work and the pole erection work using the grip-type hole digging pole erection vehicle 1 of this embodiment will be described in order.

[0073] [1. Excavation work] First, an excavation operation (hole digging operation) is performed by the grip-type pole hole digging vehicle 1. Fig. 15 is a schematic diagram showing an excavation operation by the auger device 20. In the following description, unless otherwise specified, it is assumed that the mode selection switch 33 is set to the normal mode.

[0074] When performing excavation work using the grip-type pole hole digger 1, first, the auger support 17 is connected to the tip boom 13c, and then the operation device 31 is operated to raise and lower the boom 13 by a predetermined angle (for example, 60 degrees). In this state, the auger device 20 is removed from the auger storage device and suspended vertically downward from the tip of the boom 13. Next, the operation device 31 is operated to raise and lower, extend and retract the boom 13, and move the auger screw 25 above the excavation position. Next, the mode selection switch 33 is switched from the normal mode to the auger vertical movement mode. As a result, while rotating the auger screw 22, the auger screw 25 is controlled to move vertically downward by linking the lowering and retracting operations of the boom 13, and the auger screw 25 performs the work of digging the ground vertically.

[0075] At this time, when the ground being excavated is hard, the auger screw 25 (axis J) may tilt forward, backward, left, right, and so on with respect to the vertical direction due to the excavation reaction force (excavation resistance) from the ground. The inclination angle of the auger screw 25 is detected every moment by the auger inclination angle detector 123 provided on the upper surface of the auger device 20. Based on the detection information from the auger inclination angle detector 123, the auger inclination determination unit 103 of the controller 100 determines whether the inclination angle of the auger screw 25 exceeds the allowable angle. When the auger inclination determination unit 103 determines that the inclination angle of the auger screw 25 exceeds the allowable angle, it forcibly stops the rotation operation and vertical lowering operation of the auger screw 25 (restricts the excavation operation of the auger screw 25). When the excavation operation of the auger screw 25 is restricted in this way, the operator operates the operating device 31 to vertically raise the auger screw 25, thereby pulling out the auger screw 25 from the ground (pillar hole). This allows the auger screw 25 to return to a state in which it is suspended vertically downward from the tip of the boom 13 under the action of its own weight. The auger screw 25 can then be rotated and lowered vertically again, and the auger screw 25 can be reinserted into the post hole being excavated to re-dig the post hole, thereby forming a vertical post hole.

[0076] [2. Pole erection work] Next, the pole erection work will be described. The pole erection work described below is the pole erection work of the utility pole P called a flanged divided pole, and first, the lower utility pole P(L) is erected, and then the upper utility pole P(U) is joined to the lower utility pole P(L). This joining is performed by joining the lower utility pole flange F(L) of the lower utility pole P(L) to the upper utility pole flange F(U) of the upper utility pole P(U) with the bolt BT and nut NT (see FIG. 18(B)). For this reason, the pole erection work of inserting the lower utility pole (L) into the pole erection hole will be described first. FIG. 16 is a schematic diagram showing the operation of the gripping part 81 when the automatic vertical switch 34 is operated, and FIG. 17 is a schematic diagram for explaining the direction of the load acting on the gripping part 81. In the following explanation, unless otherwise specified, the mode selection switch 33 is assumed to be in the normal mode.

[0077] When performing pole erection work using the grip-type hole digging pole erection vehicle 1, first, the operating device 31 is operated to appropriately operate the boom 13, and the arm 51 is bent and extended, and the gripping part 81 is swung vertically, swung horizontally, rotated, etc., so that the gripping part 81 is attached to the lower utility pole P(L) (e.g. The gripping portion 80 is then moved close to the lower utility pole P(L) (for example, laid horizontally at the work site) to align the gripping portion 81 with the lower utility pole P(L). Next, the pair of gripping claws 82 are operated in the closing direction (closing operation) to cause the gripping portion 80 to grip the lower utility pole P(L). Note that, in this state in which the gripping portion 81 grips the lower utility pole P(L), the gripping portion load detector 125 detects the load acting on the gripping portion 81 from moment to moment, and this detection signal is input to the controller 100. Next, the boom 13 and the gripping device 50 are appropriately operated to lift the lower utility pole P(L) gripped by the gripping portion 81 and move it above the post hole (the post hole excavated in the excavation work described above).

[0078] Then, above the pole hole, the worker operates the operating device 31 to visually bring the lower utility pole P(L) closer to a vertical position, as shown in FIG. 16(A). When the utility pole is brought to a vertical position to some extent in this way, the worker turns on the automatic vertical switch 34. When the automatic vertical control unit 105 of the controller 100 receives an operation signal from the automatic vertical switch 34 and determines that the tilt angle of the gripper 81 is within a predetermined angle, it outputs a command signal to the operation control unit 102. When the operation control unit 102 receives a command signal from the automatic vertical control unit 105, it operates the vertical swing cylinder 62 to extend and retract based on the detection information from the gripper tilt angle detector 124 to correct the tilt of the gripper 81 in the front-rear direction, and rotates the gripper motor 79 to correct the tilt of the gripper 81 in the left-right direction, thereby bringing the gripper 81 into a horizontal position. As a result, the lower utility pole P(L) gripped by the gripper 81 can be brought into a vertical position as shown in FIG. 16(B). In addition, if there is a misalignment between the vertically positioned lower utility pole P(L) and the post hole (front, back, left, right), the boom 13 is operated to extend and revolve, thereby moving the lower utility pole P(L) horizontally (front, back, left, right) while maintaining it in a vertical position, and adjusting the lower utility pole P(L) to a position directly above the post hole.

[0079] Next, in order to move the lower utility pole P(L) in a vertical position vertically downward toward the post hole, the mode selection switch 33 is operated to switch from the normal mode to the gripper horizontal / vertical movement mode. As shown in FIG. 17(A), when the gripper 81 grips the lower utility pole P(L) in a vertical position, a load corresponding to the weight of the lower utility pole P(L) acts downward on the gripper 81. Next, after switching the mode selection switch 33 to the gripper horizontal / vertical movement mode in this way, control is performed to link the hoisting and telescopic operation of the boom 13 with the vertical swinging operation of the gripper 81 in response to the operation of the boom rotation hoisting operation lever 32a, and the gripper 81 is moved vertically downward. As a result, the lower utility pole P(L) gripped by the gripper 81 is inserted into the post hole.

[0080] When the gripping portion 81 is moved vertically downward and the lower end of the lower utility pole P(L) gripped by the gripping portion 81 abuts against the bottom of the post hole, the gripping portion 81 receives a ground reaction force (a force pushing up the utility pole) from the bottom of the hole via the lower utility pole P(L). As a result, as shown in FIG. 17(B), the load acting on the gripping portion 81 is reversed from downward to upward. At this time, the load determination portion 106 of the controller 100 outputs a restriction signal to the operation control portion 102 when the load acting on the gripping portion 81 becomes 0, and stops the vertical downward movement of the gripping portion 102. As a result, when the lower end of the lower utility pole P(L) abuts against the bottom of the post hole, the vertical downward movement of the gripping portion 81 (utility pole) is stopped, and the utility pole is positioned relative to the post hole. After inserting the lower utility pole P(L) to the bottom of the post hole in this way, the gap between the lower utility pole P(L) and the post hole is filled with soil and sand, etc., and compacted (by backfilling with excavated soil, broken stones, etc.), so that the lower part of the lower utility pole P(L) can be buried in the post hole and compacted. This completes the pole installation work of installing the lower utility pole P(L) in the post hole.

[0081] Once the lower utility pole P(L) has been erected in this manner, the next step is to install the upper utility pole P(U) on top of it. This pole erection work will be described with reference to Fig. 18. In this pole erection work, first, the gripping part 81 is moved close to the upper utility pole P(U) (for example, laid horizontally at the work site), the gripping part 81 is aligned with the upper utility pole P(U), and the gripping claws 82 are closed. The gripper 80 is operated (closed) to grip the upper utility pole P(U). Next, the upper utility pole P(U) gripped by the gripper 81 is lifted and moved to above the lower utility pole P(L) that has already been erected. At this time, the operator operates the operating device 31 to visually bring the upper utility pole P(U) closer to a vertical posture. Furthermore, when the automatic vertical switch 34 is turned on, the operation control unit 102 performs control to correct the tilt of the gripper 81 in the front-rear direction by extending and retracting the vertical swing cylinder 62 based on the detection information from the gripper tilt angle detector 124, and to correct the tilt of the gripper 81 in the left-right direction by rotating the gripper motor 79, so that the gripper 81 is in a horizontal posture. With this control, the upper utility pole P(U) gripped by the gripper 81 can be in a vertical posture as shown in FIG. 18(A).

[0082] The upper utility pole flange F(U) of the upper utility pole P(U) thus placed in a vertical position is positioned so as to face the lower utility pole flange F(L) of the lower utility pole P(L) that has been erected in the vertical direction. If the positions (front-rear and left-right positions) of the upper utility pole flange F(U) of the upper utility pole P(U) placed in a vertical position and the lower utility pole flange F(L) of the lower utility pole P(L) are misaligned, the boom 13 is telescopically operated and rotated to move the upper utility pole P(U) in the horizontal direction (front-rear and left-right directions) while maintaining the vertical position, thereby adjusting the position. In this state, the upper utility pole P(U) is moved vertically downward to bring the upper utility pole flange F(U) and the lower utility pole flange F(L) into contact with each other, as shown in FIG. 18(B), and a bolt BT is inserted through the through hole H(U) of the upper utility pole flange F(U) and the through hole H(L) of the lower utility pole flange F(L), and a nut NT is attached to the bolt. In this way, by connecting the upper utility pole flange F(U) and the lower utility pole flange F(L), the lower utility pole P(L) is attached to the top of the upper utility pole P(U) and the pole erection work is completed.

[0083] In this operation, as shown in FIG. 18(B), when the upper utility pole flange F(U) and the lower utility pole flange F(L) are brought into contact with each other, if the through hole H(U) of the upper utility pole flange F(U) and the through hole H(L) of the lower utility pole flange F(L) are aligned, the bolt BT can be inserted therein and the nut NT can be fastened, but they do not necessarily align, and in many cases they do not align. In this case, the gripped object rotational movement mode is selected by the mode selection switch 33, and the boom rotation operation lever 32a, which functions as a rotational movement operation lever, is operated to adjust the position. When the boom rotation operation lever 32a is operated, control is performed in the gripped object rotational movement mode described above, and in a state where the pillar-shaped object is supported by the gripping part 81 of the gripper 80 in a vertically extended state, the vertical central axis of the pillar-shaped object is left as it is, and control is performed to rotate the pillar-shaped object around this vertical central axis. This control makes it possible to adjust the rotational position to align the through hole H(U) of the upper utility pole flange F(U) with the through hole H(L) of the lower utility pole flange F(L), and it becomes possible to insert the bolt BT through the through hole H(U) of the upper utility pole flange F(U) and the through hole H(L) of the lower utility pole flange F(L) and to attach the nut NT to it.

[0084] The main effects achieved in this embodiment can be summarized as follows:

[0085] First, according to this embodiment, if the auger screw 25 exceeds the allowable angle with respect to the vertical and tilts forward, backward, left or right, the operation of the boom 13 and the auger screw 25 can be regulated to automatically stop the excavation work of the auger screw 25, thereby making it possible to prevent a pole hole for erecting a utility pole from being formed at an angle with respect to the vertical.

[0086] In addition, according to this embodiment, when the gripping portion 81 is moved downward to insert the utility pole held by the gripping portion 81 into a pole hole (a pole hole for erecting a pole-shaped object), if the load acting on the gripping portion 81 falls below a threshold load, it is determined that the lower end of the utility pole has come into contact with the bottom of the pole hole, and the downward movement of the gripping portion 81 (utility pole) is automatically stopped, thereby preventing the worker from However, it is possible to avoid the situation where the gripping portion 81 continues to move downward without noticing that the lower end of the utility pole has come into contact with the bottom of the hole (whereby the lower end of the utility pole is pressed excessively against the bottom of the hole), and it is possible to prevent a situation in which excessive load is applied to the gripping portion 81 or the utility pole, causing damage.

[0087] Furthermore, according to this embodiment, when the automatic vertical switch 34 is operated, the posture of the gripping part 81 is changed by activating the vertical swivel cylinder 62 and the gripper motor 79 in accordance with the inclination angle of the gripping part 81 relative to the horizontal plane detected by the gripping part inclination angle detector 124, so that the utility pole gripped by the gripping part 81 can be brought into a vertical posture along the vertical direction. Therefore, even on sloping ground such as mountainous areas, the utility pole gripped by the gripping part 81 can be automatically brought into a vertical posture without the need for skilled operating skills, making it possible to dramatically improve the work efficiency of pole erection work.

[0088] Furthermore, in this embodiment, control is performed to bring the utility pole held by the gripping part 81 into a vertical position only when the inclination angle of the gripping part 81 relative to the horizontal plane detected by the gripping part inclination angle detector 124 is within a specified angle. This makes it possible to limit the range of motion for changing the gripping part 81 into a vertical position, thereby preventing the utility pole from interfering with surrounding structures or the ground or coming into contact with the worker, and ensuring the safety of the work.

[0089] In addition, in this embodiment, the work of erecting a utility pole P, which is called a flanged divided pole, can also be easily performed. In this pole erection work, the lower utility pole P(L) is erected first, and the upper utility pole P(U) is joined to the lower utility pole P(L). As described above, this joining work is performed by joining the lower utility pole flange F(L) of the lower utility pole P(L) to the upper utility pole flange F(U) of the upper utility pole P(U) with the bolt BT and nut NT. In this work, when the upper utility pole flange F(U) and the lower utility pole flange F(L) are abutted against each other, the through hole H(U) of the upper utility pole flange F(U) and the through hole H(L) of the lower utility pole flange F(L) are often not aligned. In this case, the gripped object rotation movement mode can be selected by the mode selection switch 33, and the rotation position can be adjusted by operating the boom rotation operation lever 32a, which functions as a rotation movement operation lever. This control makes it possible to easily adjust the rotational position to align the through hole H(U) of the upper utility pole flange F(U) with the through hole H(L) of the lower utility pole flange F(L), facilitating the work of inserting the bolt BT through the through hole H(U) of the upper utility pole flange F(U) and the through hole H(L) of the lower utility pole flange F(L) and then fastening the nut NT to it.

[0090] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the gist of the present invention.

[0091] In the above embodiment, the gripping portion load detector 125 is configured by a pin-type load cell that detects the load acting on the connecting pin 63, but this configuration is not limited to this. For example, the gripping portion load detector 125 may be configured by a pressure detector that detects the pressure of hydraulic oil supplied to the bottom side oil chamber and / or rod side oil chamber of the vertical swing cylinder 62.

[0092] In the above embodiment, the gripping force of the gripping portion 81 (the force with which the gripping claws 82 grip the object) is indirectly detected based on the pressure in the rod side oil chamber of the gripper cylinder 99, but this configuration is not limited to this. For example, the gripping force of the gripping portion 81 may be directly detected by providing a load cell or strain gauge inside the gripping claws 82.

[0093] In the above embodiment, the operating device 31 is provided on the operating seat 30 on the vehicle body 2, but this configuration is not limited to this, and for example, the operating device 31 may be configured as a wired or wireless remote control operating device (portable operating device).

[0094] In addition, in the above embodiment, a PTO-driven pole hole digger vehicle is exemplified, in which engine power is extracted by a PTO mechanism (power take-off mechanism) to drive a hydraulic pump. However, the present invention is not limited to this configuration, and may also be an electrically powered (battery-powered) pole hole digger vehicle, or a hybrid type pole hole digger vehicle that has both and can selectively switch between power sources. [Explanation of symbols]

[0095] 1. Grab-type hole digging vehicle 2. Vehicle body 12 Swivel table 13 Boom 20 Auger device 22 Auger motor 25 Earth auger 31 Operating device 33 Mode Select Switch 34 Automatic Vertical Switch 50 Grasping device 51 Arm 55 arm cylinder 60 first joint member 62 vertical swivel cylinder 70 second joint member 71 Swing cylinder 79 Gripper motor 80 Gripper 81 Gripping part 82 Grip jaw 99 Gripper cylinder 100 Controller 101 Position calculation unit 102 Operation control unit 103 Auger inclination determination unit 104 Grip determination section 105 Automatic vertical control section 106 Load determination unit 123 Auger inclination angle detector 124 Grip inclination angle detector 125 Grip load detector 126 Gripper cylinder pressure detector

Claims

1. A grip-type work vehicle comprising: a vehicle body; a boom mounted on the vehicle body so as to be capable of rotating, raising and lowering, and extending; a gripping section for gripping a pillar-shaped object; a support mechanism provided between the tip of the boom and the gripping section for changing the attitude of the gripping section relative to the tip of the boom; and a control device for controlling the operation of the boom and the support mechanism, the control device is capable of controlling the horizontal movement of the gripper by combining control of the rotation, elevation, and extension operation of the boom with control of the operation of the support mechanism; The support mechanism has a left-right swing mechanism that swings the gripper left and right, The control device is capable of controlling the gripping part to swivel using the left and right swivel mechanism while holding a vertically extending pillar-like object by the gripping part, controlling the boom to rotate, and controlling the gripping part to move in the horizontal forward and backward directions in a combined manner, thereby enabling control to rotate the pillar-like object gripped by the gripping part around a vertically extending central axis.

2. The grip-type work vehicle described in claim 1, characterized in that the control device is capable of controlling the gripping part to swivel using the left and right swivel mechanism while a pillar-like object is extended vertically and gripped by the gripping part, controlling the rotation operation of the boom to return the left and right movement of the pillar caused by the left and right swivel operation to its original position, and controlling the gripping part to move in the horizontal forward and backward directions to return the forward and backward movement of the pillar caused by the swivel operation of the gripping part and the rotation operation of the boom to its original position, thereby rotating the pillar gripped by the gripping part about a vertically extending central axis.

3. A grip-type work vehicle comprising: a vehicle body; a boom mounted on the vehicle body so as to be capable of rotating, raising and lowering, and extending; a gripping section for gripping a pillar-shaped object; a support mechanism provided between the tip of the boom and the gripping section for changing the attitude of the gripping section relative to the tip of the boom; and a control device for controlling the operation of the boom and the support mechanism, the control device is capable of controlling the horizontal movement of the gripper by combining control of the rotation, elevation, and extension operation of the boom with control of the operation of the support mechanism; The support mechanism has a left-right swing mechanism that swings the gripper left and right, The control device, when the gripping unit is holding a vertically extending pillar-shaped object, moves the gripping unit horizontally so that the left and right swing center of the gripping unit moves along a trajectory that rotates around the vertically extending central axis of the pillar held by the gripping unit, and controls the gripping unit to swing left and right so that the pillar held by the gripping unit rotates without moving its central axis, thereby enabling control to rotate the pillar held by the gripping unit around its vertically extending central axis.

4. The gripping portion has a pair of openable and closable gripping claws for gripping a columnar object, The support mechanism has a rotation mechanism that rotates the gripping jaws about a rotation axis perpendicular to the opening and closing direction of the gripping jaws, A gripping type work vehicle as described in any one of claims 1 to 3, characterized in that the gripping claws can be rotated by the rotation mechanism to adjust the angle at which the pillar-shaped object gripped by the gripping claws is held.

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