JP7777990B2 - Control device for grip-type hole-digging and pole-setting vehicle - Google Patents

Description

The present invention relates to a control device for a gripping-type pole-digging vehicle equipped with a gripping device for gripping, for example, a pole-shaped object.

A known pole hole digger, a type of work vehicle, is a gripping-type pole hole digger, equipped with a swivel base mounted on the vehicle body for free rotation, a boom mounted on the swivel base for free extension and retraction, an auger device attached to the boom for digging a pole hole for installing a utility pole, and a gripping device attached to the tip of the boom for gripping a pole-shaped object such as a utility pole (see, for example, Patent Document 1). When using this gripping-type pole hole digger to excavate a pole hole in the ground, the auger device is suspended from the tip of the boom and the boom is operated as needed. The auger device is then rotated at a predetermined excavation position to create a pole hole of a predetermined depth. After the pole hole is excavated, the auger device is raised and stored on the side of the boom, and the utility pole is gripped by the gripping device attached to the tip of the boom. With the pole still gripped, the boom is operated as needed to directly install the utility pole into the excavated pole hole. This type of gripping-type hole-digging pole erection vehicle allows the entire pole erection process to be carried out more efficiently than when the pole is hoisted using a winch or crane.

Japanese Patent Application Publication No. 2-81892

However, when the gripping device holding the utility pole is moved downward to insert the utility pole into the post hole, it is difficult for the worker to visually determine whether the lower end of the utility pole is abutting against the bottom of the post hole. If the worker continues to move the gripping part downward without recognizing that the lower end of the utility pole is abutting against the bottom of the post hole, there is a problem in that the gripping device and utility pole may be subjected to a large reaction force (load) from the ground, which could cause them to be damaged.

The present invention was made in consideration of these issues, and aims to provide a control device for a gripping-type pole-setting vehicle that can detect when a pole-shaped object gripped by the gripping section has reached the bottom of the pole-setting hole.

To solve the above problems, the control device for a gripping-type pole digging vehicle according to the present invention is characterized by comprising: a boom mounted on a vehicle body capable of raising and lowering and extending; a gripping unit capable of gripping a pillar; a support mechanism mounted between the tip of the boom and the gripping unit and adapted to change the attitude of the gripping unit relative to the tip of the boom; an operating device for controlling the operation of the boom, the gripping unit, and the support mechanism; a load detector for detecting the load acting on the gripping unit when the gripping unit is gripping a pillar; an operation control unit for controlling the operation of the boom, the gripping unit, and the support mechanism in response to operation of the operating device; and an operation restriction unit for restricting the downward movement of the gripping unit by the boom and the support mechanism when the load detected by the load detector falls below a preset threshold when the operation control unit operates the boom and the support mechanism to move the gripping unit gripping a pillar downward.

In the control device for the grip-type pole digging vehicle configured as described above, the operating device includes a gripper vertical operation operating device that is operated to move the gripper in the vertical direction, the operation control unit controls the vertical movement of the gripper by linking the raising and lowering operation of the boom with the operation of the support mechanism in response to the operation of the gripper vertical operation operating device, and the operation restriction unit preferably restricts the vertical downward movement of the gripper by the boom and the support mechanism when the load detected by the load detector falls below the threshold value while the operation control unit is operating the boom and the support mechanism to move the gripper gripping a pillar vertically downward.

The control device for the grip-type pole-digging vehicle of the present invention moves the gripper downward to insert the pole-shaped object held by the gripper into a pole-setting hole (a hole for inserting the pole), and if the load acting on the gripper falls below a threshold, it determines that the lower end of the pole has come into contact with the bottom of the pole-setting hole, and automatically stops the downward movement of the gripper (pole-shaped object). This prevents the operator from continuing to move the gripper downward without realizing that the bottom of the pole has come into contact with the bottom of the hole (which would cause the bottom end of the pole to be pressed excessively against the bottom of the hole), and makes it possible to prevent excessive loads from being applied to the gripper or pole-shaped object, which could cause damage.

FIG. 2 is a side view of the gripping-type hole-digging pole-setting vehicle according to the present embodiment. FIG. 2 is a plan view of the above-mentioned gripping-type hole digging and pole erection vehicle. FIG. 2 is a side view showing the use state of the above-mentioned grip-type hole digging pole erection vehicle. FIG. 2 is a perspective view of an auger device provided on the grip-type hole digging pole erection vehicle. FIG. 2 is a perspective view of a gripping device provided on the gripping-type hole-digging pole-setting vehicle. FIG. 2 is a perspective view of the main part of the gripping device as seen from the right. FIG. 2 is a perspective view of the main part of the gripping device as seen from the left. FIG. 2 is a cross-sectional view of the gripping device. FIG. 2 is a longitudinal sectional view of the gripping device. This is a side view of a pole extraction device provided on the above-mentioned gripping-type hole digging and pole erection vehicle. FIG. 2 is a functional block diagram of the above-mentioned gripping-type hole digging pole erection vehicle. 10A and 10B are schematic diagrams for explaining an operation of setting the gripping portion of the gripping device in a horizontal position. 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. FIG. 2 is a schematic diagram showing the excavation work of the above-mentioned gripping-type hole digging pole erection vehicle. This 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 erection vehicle is operated. 10 is a schematic diagram illustrating the direction of the load acting on the gripping portion during the process of inserting the utility pole held by the gripping portion into a pole hole. FIG. FIG. 2 is a schematic diagram showing the flow of an automatic pole removal operation using the pole removal device. FIG. 17 is a schematic diagram showing the flow of automatic pole erection work using the pole extraction device (continuation of FIG. 17). FIG. 18 is a schematic diagram showing the flow of automatic pole erection work using the pole extraction device (continuation of FIG. 18).

A preferred embodiment of the present invention will now be described with reference to the drawings. First, the overall configuration of the grip-type hole-digging pole-setting vehicle 1 according to this embodiment will be described with reference to Figures 1 to 3.

As shown in Figure 1, the grip-type hole-digging and pole-setting vehicle 1 has a driver's cabin 7 at the front of the vehicle body 2 and is based on a truck vehicle that can travel on a pair of left and right tires and wheels 5 located at the front and rear of the vehicle body 2. Jacks 9 for lifting and supporting the vehicle body 2 are located 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) located inside it and extending it downward, thereby stabilizing the entire vehicle body 2. The jacks 9 are operated by operating a jack operating device (not shown) located at the rear of the vehicle body 2.

A swivel base 12 is provided in the mounting area behind the driver's cabin 7 on the vehicle body 2. The swivel base 12 is driven by a swivel motor 14 (see Figure 11) and is configured to rotate horizontally around a vertical axis. The base end of a boom 13 is attached to the swivel base 12 so that it can swing (raise and lower) in the vertical direction.

The boom 13 is composed of, in order from the swivel base 12 side, a base boom 13a, an intermediate boom 13b, and a tip boom 13c nested together. The boom 13 can be extended and retracted in the axial (longitudinal) direction by the extension and retraction of a telescopic cylinder 15 (see Figure 11) installed inside. A boom derrick cylinder 16 is also installed between the base boom 13a and the swivel base 12. By extending and retracting this boom derrick cylinder 16, the entire boom 13 can be raised and lowered in the vertical plane.

An auger support 17 is attached to the boom 13, and can be selectively connected to the base boom 13a and the tip boom 13c. As shown in FIG. 4, the upper shaft 27a of a connecting rod member 27 is pivotally connected to the auger support 17 so that it can swing left and right. An auger device 20 for drilling post holes is pivotally connected to the lower shaft 27b of the connecting rod member 27 so that it can swing forward and backward. The auger device 20 comprises an auger motor unit 21 pivotally connected to the lower shaft 27b of the connecting rod member 27, and an auger screw (earth auger) 25 that rotates around its axis when the auger motor unit 21 is operated. The auger motor unit 21 comprises an auger motor 22 that is hydraulically rotated, 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 auger reducer 23. The drive shaft (not shown) of the auger reducer 23 protrudes from the lower end of the auger housing 24, and the upper end of the auger screw 25 is connected to this drive shaft.

An auger storage device 18 that holds the auger device 20 in a stored state is also provided on the side of the base boom 13a. The auger device 20 is attached to the auger support 17 via a connecting rod member 27 so that it can swing up and down in a vertical plane. The auger device 20 can be swung between a storage 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 detached from the auger storage device 18 and the auger screw 25 is suspended toward the ground. When in the working position, the auger device 20 is suspended from the tip of the boom 13 so that it can swing freely in the front-to-back and left-to-right directions around the two shafts 27a, 27b of the connecting rod member 27 as fulcrums, so that the auger screw 25 maintains a vertical position aligned with the direction of gravity (vertical direction) regardless of the position of the boom 13.

When the auger device 20 is in use, as shown in I of Fig. 3 , the auger support 17 is connected to the distal boom 13c, and the auger device 20, detached from the auger retracting device 18, is swung to the working position (with the auger screw 25 in a substantially vertical position relative to the ground). Then, the auger screw 25 is rotated by the rotational drive of the auger motor 22, while the boom 13 is lowered and retracted in conjunction with each other to move linearly downward, thereby enabling excavation of a pole hole. On the other hand, when the auger device 20 is not in use, as shown in II of Fig. 3 , the auger support 17 is connected to the proximal boom 13a, and the auger retracting device 18 stores and holds the auger device 20 in a storage position along the side of the proximal boom 13a. When the auger device 20 is in the storage position, various operations can be performed using the gripping device 50, which will be described later, such as erecting and removing utility poles (indicated by the symbol P in Fig. 3 ; the same applies hereinafter), and relocating obstacles.

An arm bracket 19 is fixed to the tip of the tip boom 13c. Attached to this arm bracket 19 is a gripping device 50 that grips an object (pillar-shaped object), such as a utility pole or a tree. The configuration of this gripping device 50 will be explained with additional reference to Figures 5 to 9. Note that in Figures 8 to 9, hatching indicating cross sections has been omitted to make the drawings easier to see. For ease of explanation, the orientation of the gripping device 50 shown in Figure 5 will be used as the reference, and the directions indicated by the front-to-back, left-to-right, and up-to-down arrows in the illustration will be referred to as the front-to-back direction, left-to-right direction, and up-to-down direction.

The gripping device 50 is configured to include an arm 51 attached to the arm bracket 19 so that it can swing (bend and stretch) in the vertical direction, a first joint member 60 attached to the tip of the arm 51 so that it can swing (vertical swing) in the vertical direction, a second joint member 70 attached to the first joint member 60 so that it can swing (horizontal swing) in the left-right direction, and a gripper 80 rotatably attached to the second joint member 70. In this embodiment, a support mechanism that changes the posture of the gripping portion 81 of the gripper 80 is configured by the arm 51, first joint member 60, second joint member 70, vertical swing cylinder 62 (described below), horizontal swing cylinder 71, gripper motor 79, etc.

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 the first joint member 60 via a connecting pin 53. An arm cylinder 55 is attached between the arm bracket 19 and the arm 51. The rod side end of the arm cylinder 55 is pivotally connected to the arm bracket 19 via a connecting pin 56. The bottom side end of the arm cylinder 55 is pivotally connected to the tip side of the arm 51 via a connecting pin 57. By extending and retracting this arm cylinder 55, the arm 51 can be freely swung (bendable and extendable) in the vertical direction relative to the arm bracket 19 around the connecting pin 52.

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

The second joint member 70 is supported by the first joint member 60 so that it is sandwiched between them from above and below. A horizontal swivel cylinder 71 is provided at the upper end of the first joint member 60. The bottom end of the horizontal swivel cylinder 71 is pivotally connected to the tip of the first joint member 60, and the rod end is pivotally connected to the rear end of the second joint member 70. By extending and retracting this horizontal swivel cylinder 71, the second joint member 70 can be freely swung left and right (horizontally swivelable) relative to the first joint member 60 around the connecting pin 61.

The gripper 80 comprises a gripping portion 81 for gripping 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.

The gripping unit 81 includes a pair of gripping claws 82 and a pair of upper and lower support plates 83 that support the pair of gripping claws 82 so that they can open and close in directions that move them toward and away from each other (opening and closing directions). The gripping claws 82 are configured to be able to 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 plates 83 via connecting pins 84. Alternating notches 82a and 82b are formed at the tips of the gripping claws 82, allowing these tips to intersect (overlap) with each other. The support plate 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).

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

The support tube 87 has a dual structure, including an inner tube 88 formed in a hollow rectangular tube shape and an outer tube 89 formed in a hollow cylindrical shape and attached to the outer periphery of the inner tube 88. A sliding member 95 of the opening/closing mechanism 93 (described below) is attached to the inner periphery of the inner tube 88 so as to slide freely forward and backward. A worm wheel 90 is attached concentrically to the outer periphery of the outer tube 89. The worm wheel 90 meshes with a worm pinion 91 rotatably supported 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 Figure 8) via the worm pinion 91 and 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 specified direction around the rotation axis X (see Figure 8) via the worm pinion 91 and worm wheel 90. Note that in the position of the gripping device 50 shown in Figure 5, the direction of the rotation axis X of the gripper 80 (gripping portion 81) corresponds to the front-to-back direction, and the opening/closing direction (gripping direction) of the gripping portion 81 corresponds to the left-to-right direction.

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 an intermediate portion of the gripping claw 81 via a connecting pin 96. The other ends of the pair of link members 94 are pivotally connected to the tip end of the sliding member 95 via a connecting pin 97, with the other ends of the link members 94 stacked vertically. The sliding member 95 is inserted into the hollow portion of the inner cylindrical portion 88 and is attached so as to be slidable (reciprocating) along the inner circumferential surface of the inner cylindrical portion 88. A synthetic resin slider 98 is attached between the outer circumferential surface of the sliding member 95 and the inner circumferential surface of the inner cylindrical portion 88 to guide the sliding (reciprocating movement) of the sliding member 95. The rod side end of the gripper cylinder 99 is connected to the base end of the sliding member 95. The bottom end of the gripper cylinder 99 is connected to the cylinder bracket portion 92 of the gripper housing 86. When the gripper cylinder 99 is extended, the sliding member 95 slides in the extension direction, causing the link members 94 to swing away from each other. This causes the gripping claws 82 to 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 releasing the grip of the object. On the other hand, when the gripper cylinder 99 is retracted, the sliding member 95 slides in the retraction direction, causing the link members 94 to swing toward each other. This causes the gripping claws 82 to swing in the closing direction with the connecting pin 84 as a fulcrum (the gripping claws 82
2 is operated in the closing direction (closing operation), the object can be grasped. Note that since the opening and closing mechanism 93 is configured symmetrically, the pair of gripping claws 82 are opened and closed symmetrically.

An operator's seat 30 is provided on the side of the swivel base 12 of the vehicle body 2 for operating each work device (swivel base 12, boom 13, auger device 20, and gripping device 50). In front of this operator's seat 30 is an operating device 31 that can be operated by the operator while seated. As shown in FIG. 11, the operating device 31 is provided with a boom rotation/hoisting operation lever 32a for rotating and raising/lowering the boom 13, a boom extension/retraction operation lever 32b for extending/retracting the boom 13 and bending/extending the arm 51, an auger operation lever 32c for rotating the auger screw 25, a gripper vertical swing operation lever 32d for vertically swinging the gripper 81, a gripper horizontal swing operation lever 32e for horizontally swinging the gripper 81, a gripper rotation operation lever 32f for rotating the gripper 81, and a gripper opening/closing operation lever 32g for opening and closing the gripper 81.

The operating device 31 also includes a pole extractor operating lever 32h for operating the pole extractor 40 (pulling out the utility pole), which is used as an optional hydraulic device. As shown in FIG. 10, the pole extractor 40 comprises a hydraulically retractable pole extractor cylinder 41, a base plate 44 attached to the lower end of the pole extractor cylinder 41 and grounded to the ground, and a chain 45 attached to the upper end of the pole extractor cylinder 41 and wound around the utility pole (indicated by the symbol P in FIG. 10). The pole extractor cylinder 41 comprises a cylinder tube 42 and a piston rod 43 attached to the cylinder tube 42 so as to be vertically retractable. Both ends of the chain 45 are detachably attached to the upper end of the cylinder tube 42 of the pole extractor cylinder 41. The chain 45 is formed to a length that allows it to be wound around the outer circumference of the utility pole several times. A base plate 44 is pivotally connected to the lower end of the piston rod 43 around a support shaft 44a so that it can swing freely (allowing it to swing in response to the slope and unevenness of the ground). The pole extractor cylinder 41 is also connected to a hydraulic hose 46 connected to the bottom oil chamber of the cylinder tube 42 and a hydraulic hose 47 connected to the rod oil chamber of the cylinder tube 42. These hydraulic hoses 46, 47 are connected to a pole extractor hydraulic outlet (not shown) on the vehicle body 2 using a seal coupling (one-touch joint). This hydraulic outlet connects the oil chambers (bottom oil chamber, rod oil chamber) of the pole extractor cylinder 41 to the ports of the electromagnetic proportional control valve V10, allowing hydraulic oil (pressurized oil) to be supplied and discharged between the pole extractor cylinder 41 and the electromagnetic proportional control valve V10.

The operating device 31 is also provided with a mode selection switch 33, an automatic vertical switch 34, and an automatic column removal switch 35, as shown in Figure 11.

The mode selection switch 33 is configured as a toggle switch that can be switched between a neutral position, a forward position, and a rearward position (the switched operating position is maintained even if the operator releases the switch). When the mode selection switch 33 is in the neutral position, the normal mode is selected, when the mode selection switch 33 is in the forward position the auger vertical operation mode is selected, and when the mode selection switch 33 is in the rearward position the gripper vertical operation mode is selected. The normal mode is a mode in which the hydraulic actuators are independently operated in response to the operation of the control levers 32a to 32h to individually perform operations such as raising, lowering, and rotating the boom 13, rotating the auger device 20 (auger screw 25), bending and extending the arm 51, swinging vertically, swinging horizontally, rotating, and opening and closing the gripper 81, and extending and retracting the pole extractor 40. The vertical auger operation mode is a mode in which the hoisting cylinder 16 and the telescopic cylinder 15 are operated in combination (interlocked operation) in response to operation of the boom rotation/hoisting control lever 32a, thereby moving the auger device 20 (the tip of the boom 13) in the vertical direction (up and down).The vertical gripper operation mode is a mode in which the hoisting cylinder 16, the telescopic cylinder 15, and the vertical swing cylinder 62 are operated in combination (interlocked operation) in response to operation of the boom rotation/hoisting control lever 32a, thereby moving the gripper 81 in the vertical direction (up and down).

The automatic vertical switch 34 is a toggle switch that can be switched between an ON position and an OFF position (it is configured to maintain the switched operating position even if the operator releases it). When the automatic vertical switch 34 is selected for the ON position, as will be described in detail below, the vertical oscillating cylinder 62 and gripper motor 79 are activated to oscillate and rotate the gripper 81, thereby bringing the gripper 81 into a horizontal position (i.e., the utility pole gripped by the gripper 81 can be made vertical). Note that the operation of the automatic vertical switch 34 is valid (the operation signal is validly received) when the tilt angle of the gripper 81 with respect to the horizontal plane, detected by the gripper tilt angle detector 124 (see Figure 11), described below, is within a predetermined angle.

The automatic pole removal switch 35 is configured as a toggle switch that can be switched between either the on position or the off position (it is configured to maintain the switched operating position even if the operator releases his/her hand). When the automatic pole removal switch 35 is selected to the on position, as will be described in detail below, the gripper cylinder 99 and pole removal machine cylinder 41 are operated in conjunction with each other, combining the opening and closing operation of the gripping portion 81 with the extension and retraction operation of the pole removal machine 40 to automatically perform the pole removal work of pulling the existing utility pole out of the ground.

As shown in Figure 11, the operating mechanisms for the swivel base 12, boom 13, auger device 20, gripping device 50, and pole extractor 40 are comprised of a controller 100 that receives operation signals from the 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, gripper cylinder 99, and pole extractor cylinder 41 (hereinafter collectively referred to as "hydraulic actuators"), and a hydraulic unit 110 that supplies hydraulic oil to drive these hydraulic actuators.

Operation signals output by operating the operating device 31 are input to the controller 100. The controller 100 outputs command signals corresponding to the operation signals to the hydraulic unit 110 (control valve 112).

The hydraulic unit 110 includes a hydraulic pump 111 that discharges hydraulic oil and a control valve 112 that controls the direction and amount of hydraulic oil supplied from the hydraulic pump 111 to each hydraulic actuator. The hydraulic pump 111 is driven by power extracted from the vehicle's engine via a PTO mechanism (not shown). The control valve 112 includes an electromagnetic proportional control valve V1 corresponding to the swing motor 14, an electromagnetic proportional control valve V2 corresponding to the telescopic cylinder 15, an electromagnetic proportional control valve V3 corresponding to the elevation/depression cylinder 16, an electromagnetic proportional control valve V4 corresponding to the auger motor 22, an electromagnetic proportional control valve V5 corresponding to the arm cylinder 55, an electromagnetic proportional control valve V6 corresponding to the vertical swing cylinder 62, an electromagnetic proportional control valve V7 corresponding to the horizontal swing cylinder 71, an electromagnetic proportional control valve V8 corresponding to the gripper motor 79, an electromagnetic proportional control valve V9 corresponding to the gripper cylinder 99, and an electromagnetic proportional control valve V10 corresponding to the pole extractor cylinder 41. Based on command signals from the controller 100, this control valve 112 electromagnetically drives the spools of each electromagnetic proportional control valve V1-V10 to control the supply direction and amount of hydraulic oil supplied from the hydraulic pump 111 to each hydraulic actuator, thereby controlling the operating direction and operating speed of each hydraulic actuator (controlling the operating direction and operating speed of the swivel base 12, boom 13, auger device 20, gripping device 50, and pole extractor 40).

The controller 100 includes a boom hoisting angle detector 120, a boom extension amount detector 121,
Various detectors such as a boom rotation angle detector 122, an auger inclination angle detector 123, a gripper inclination angle detector 124, a gripper load detector 125, a gripper cylinder pressure detector 126, and column extractor cylinder pressure detectors 127 and 128 are electrically connected.

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

The auger inclination angle detector 123 is attached to the top of the auger motor unit 21 (auger housing 24). This auger inclination angle detector 123 detects the inclination angle of the auger device 20 (auger screw 25). As mentioned above, the auger device 20 is suspended from the tip of the boom 13 around the two shafts 27a, 27b of the connecting rod member 27 as fulcrums so that the auger screw 25 maintains 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 Figure 14) using the auger device 20, if the excavation resistance of the ground is high, the axis of the auger screw 25 may tilt in the forward/backward and left/right directions relative to the vertical line (vertical direction). The auger inclination angle detector 123 is configured as a two-axis inclination angle detector that detects the inclination angle of the auger screw 25 in the left-right direction (X-axis direction) and the front-to-back direction (Y-axis direction) as the inclination angles of the auger screw 25 relative to the vertical direction. This auger inclination angle detector 123 detects the inclination angles of the auger screw 25 in the left-right direction and the front-to-back direction, and outputs a voltage signal (detection signal) corresponding to the detected inclination angles to the controller 100.

The gripping unit tilt angle detector 124 is attached to the upper surface of the gripping unit 81 (support plate portion 83). This gripping unit tilt angle detector 124 is a two-axis tilt angle detector that detects the tilt angle in the left-right direction (X-axis direction) and the front-back direction (Y-axis direction) as the tilt angle of the gripping unit 81 relative to the horizontal plane. This gripping unit tilt angle detector 124 detects the left-right tilt angle and the front-back tilt angle of the gripping unit 81, and outputs a voltage signal (detection signal) corresponding to the detected tilt angle to the controller 100.

The gripper load detector 125 is a so-called pin-type load cell, configured as the connecting pin 63 pivotally connecting the bottom end of the vertical oscillating cylinder 62 and the base end of the arm 51. The gripper load detector 125 detects the load acting in the axial direction (the axial direction of the vertical oscillating cylinder 62) from the vertical oscillating 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 (the load acting on the connecting pin 62) is proportional to the load acting on the gripper 81 (the load received by the gripper 81 in the vertical plane). Therefore, as will be described in detail below, the controller 100 determines the load acting on the gripper 81 based on the load detected by the gripper load detector 125.

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 in 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 portion 81 (the force with which the gripper portion 81 grips an object). Therefore, as will be described in detail later, the controller 100 determines the gripping force of the gripper portion 81 based on the pressure detected by the gripper cylinder pressure detector 126.

The column extractor cylinder pressure detector 127 is provided in the oil passage connecting the electromagnetic proportional control valve V10 and the bottom-side oil chamber of the column extractor cylinder 41, and detects the pressure of the hydraulic oil supplied to the bottom-side oil chamber of the column extractor cylinder 41 (the pressure in the bottom-side oil chamber). The column extractor cylinder pressure detector 128 is provided in the oil passage connecting the electromagnetic proportional control valve V10 and the rod-side oil chamber of the column extractor cylinder 41, and detects the pressure of the hydraulic oil supplied to the rod-side oil chamber of the column extractor cylinder 41 (the pressure in the rod-side oil chamber). These column extractor cylinder pressure detectors 127, 128 detect the pressure of the hydraulic oil supplied to each oil chamber (bottom-side oil chamber, rod-side oil chamber) of the column extractor cylinder 41 and output a voltage signal (detection signal) corresponding to the detected pressure to the controller 100. In this embodiment, the stroke end of the column extractor cylinder 41 in the extension/retraction direction is detected based on the pressure detected by the column extractor cylinder pressure detectors 127, 128.

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 control unit 105, a load determination unit 106, and an automatic column removal control unit 107.

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, boom extension amount detector 121, and boom rotation angle detector 122.

The operation control unit 102 controls the operation of each actuator in accordance with the operation signal (operation command) output from the operation device 31, based on the operation mode selected by the mode selection switch 33. Each operation mode is explained below.

(Normal mode)
When the mode selector switch 33 is set to the normal mode and the control levers 32a to 32h are operated, the operation control unit 102 independently activates each hydraulic actuator in response to the operation of each control lever 32a to 32h. Specifically, when the boom rotation/hoisting control lever 32a is tilted forward (in the front-to-back and left-to-right directions relative to the operator operating the lever; the same applies below), the operation control unit 102 retracts the hoisting cylinder 16 to lower the boom 13, and when the boom rotation/hoisting control lever 32a is tilted backward, the operation control unit 102 extends the hoisting cylinder 16 to raise the boom 13. Furthermore, when the boom extension/retraction control lever 32b is tilted forward, the operation control unit 102 extends the telescopic cylinder 15 to extend the boom 13, and when the boom extension/retraction control lever 32b is tilted backward, the operation control unit 102 retracts the telescopic cylinder 15 to retract the boom 13. Furthermore, when the boom swing/hoisting control lever 32a is tilted leftward, the swing motor 14 is rotated in the forward direction to swing the boom 13 counterclockwise, and when the boom swing/hoisting control lever 32a is tilted rightward, the swing motor 14 is rotated in the reverse direction to swing the boom 13 clockwise. Furthermore, when the auger control lever 32c is tilted forward, the auger motor 22 is rotated in the reverse direction to rotate the auger screw 25 in the reverse direction, and when the auger control lever 32c is tilted backward, the auger motor 22 is rotated in the forward direction to rotate the auger screw 25 in the forward direction. Furthermore, when the boom extension/contraction control lever 32b is tilted leftward, the arm 51 is flexed and extended downward relative to the tip of the boom 13, and when the boom extension/contraction control lever 32b is tilted rightward, the arm 51 is flexed and extended upward relative to the tip of the boom 13. Furthermore, 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). Furthermore, when the gripper horizontal swing operation lever 32e is tilted leftward, the horizontal swing cylinder 71 is extended to swing the gripper 81 leftward (horizontal swing), and when the gripper vertical swing operation lever 32e is tilted rightward, the horizontal swing cylinder 71 is contracted to swing the gripper 81 rightward (horizontal swing). Furthermore, when the gripper rotation operating lever 32f is tilted forward, the gripper motor 79 is operated to rotate in the forward direction and rotate the gripper 81 clockwise, and when the gripper rotation operating lever 32f is tilted backward, the gripper motor 79 is operated to rotate in the reverse direction and rotate the gripper 81 counterclockwise. Furthermore, when the gripper opening/closing operating lever 32g is tilted forward, the gripper cylinder 99 is operated to contract and operate the gripper 81 in the closing direction (direction to grip the object), and when the gripper opening/closing operating lever 32g is tilted backward, the gripper cylinder 99 is operated to extend and operate the gripper 81 in the opening direction (direction to release the grip of the object). In addition, when the pole puller operating lever 32h is tilted forward, the pole puller cylinder 41 is extended to extend the pole puller 40, and when the pole puller operating lever 32h is tilted backward, the pole puller cylinder 41 is retracted to retract the pole puller 40.

(Auger vertical operation mode)
Furthermore, when the mode selector switch 33 is set to the vertical auger operation mode and the boom swing/hoisting control lever 32a is operated, the operation control unit 102 combines and links the extension and retraction of the hoisting cylinder 16 and 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, thereby moving the auger screw 25 (tip of the boom 13) vertically in accordance with the operation of the boom swing/hoisting control lever 32a. Specifically, when the boom swing/hoisting control 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 swing/hoisting control 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.

(Grip vertical operation mode)
Furthermore, when the mode selection switch 33 is set to the gripper vertical operation mode and the boom rotation/hoisting control lever 32a is operated, the operation control unit 102 combines and links the extension and contraction operations of the hoisting cylinder 16, the extension and contraction operation of the telescopic cylinder 15, and the extension and contraction 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 (the object gripped by the gripper 81) vertically in accordance with the operation of the boom rotation/hoisting control lever 32a. Specifically, when the boom rotation/hoisting control lever 32a is tilted forward, the gripping part 81 is moved vertically downward by a combination of 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 control lever 32a is tilted backward, the gripping part 81 is moved vertically upward by a combination of the extension of the hoisting cylinder 16, the extension of the telescopic cylinder 15, and the extension of the vertical swing cylinder 62. Specifically, the vertical operation control of the gripper 81 is performed by combining control to move the tip of the boom 13 in the vertical direction by combining the extension and contraction operation of the hoisting cylinder 16 and the extension and contraction operation of the telescopic cylinder 15 based on position information of the tip of the boom 13 calculated by the position calculation unit 101, and control to maintain the gripper 81 (rotation axis X of the gripper 81) in a horizontal state by the extension and contraction operation of the vertical swivel cylinder 62 based on detection information detected by the gripper inclination angle detector 124 (the inclination angle of the gripper 81 with respect to the horizontal plane).

The auger inclination determination unit 103 determines the posture of the auger device 20 (auger screw 25) based on detection information from the auger inclination angle detector 123. Specifically, the auger inclination determination unit 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. The allowable angle is set to, for example, 5 degrees (although this setting can be changed as desired). Here, when an excavation operation combining rotation and vertical lowering of the auger screw 25 is being performed in the vertical auger operation mode, if the auger inclination determination unit 103 determines that the inclination angle of the auger screw 25 is within the allowable angle, it permits the excavation operation. However, if the auger inclination determination unit 103 determines that the inclination angle of the auger screw 25 exceeds the allowable angle, it 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, it cuts off the control signal for rotating and vertically lowering the auger screw 25 from the 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 (forming an inclined post hole). At this time, the excavation operation of the auger screw 25 (the rotational 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 moved vertically upward and temporarily pulled out of the excavated hole, so that the auger screw 25 can return to a vertical position (a position facing vertically downward) under its own weight. After returning the auger screw 25 to a vertical position in this way, the auger screw 25 can be rotated and vertically lowered again, allowing the post hole being excavated (the same post hole) to be excavated again from the middle.

The grip determination unit 104 determines the gripping state of the gripping unit 81 based on detection information from the gripper cylinder pressure detector 126. Specifically, the grip determination unit 104 determines that the gripping unit 81 is gripping the utility pole (object) (that the gripping unit 81 is gripping the utility pole with a specified gripping force) when the pressure detected by the gripper cylinder pressure detector 126 rises to or above a predetermined first threshold pressure. Furthermore, the grip determination unit 104 determines that the grip of the utility pole (object) by the gripping unit 81 has loosened (that the gripping force has weakened to the extent that the utility pole will not fall off the gripping unit 81) when the pressure detected by the gripper cylinder pressure detector 126 falls to or below a predetermined second threshold pressure (where the first threshold pressure > the second threshold pressure).

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 this automatic vertical program. When the operation control unit 102 receives a command signal from the automatic vertical control unit 105, it feeds back the tilt angle of the gripper unit 81 from the gripper tilt angle detector 124, and based on this fed-back information, it corrects the tilt of the gripper unit 81 in the front-to-rear direction by extending and contracting the vertical swing cylinder 62 until the tilt angle of the gripper unit 81 in the front-to-rear direction reaches the target angle (0 degrees), and also corrects the tilt of the gripper unit 81 in the left-to-right direction by rotating the gripper motor 79 until the tilt angle of the gripper unit 81 in the left-to-right direction reaches the target angle (0 degrees). Regarding the tilt of the gripper unit 81 in the front-to-rear direction, the gripper unit 81 can be tilted downward (see the Y1 direction in FIG. 12) by extending the vertical swing cylinder 62, and can be tilted upward (see the Y2 direction in FIG. 12) by contracting the vertical swing cylinder 62. Furthermore, with regard to the tilt of the gripper unit 81 in the left-right direction, the gripper unit 81 can be tilted leftward (see Z1 direction in FIG. 12 ) about the rotation axis X by operating the gripper motor 79 in the forward rotation direction, and the gripper unit 81 can be tilted rightward (see Z2 direction in FIG. 12 ) about the rotation axis X by operating the gripper motor 79 in the reverse rotation direction. In this way, the operation control unit 102 performs feedback control based on the deviation between the tilt angle of the gripper unit 81 and the target angle (0 degrees) based on a command from the automatic vertical control unit 105, and sets the gripper unit 81 in a horizontal position (the utility pole gripped by the gripper unit 81 in a vertical position). This automatic vertical control is used not only when gripping unit 81 is brought into a horizontal position while gripping a utility pole (i.e., when gripping unit 81 brings the utility pole it grips into a vertical position), but also when gripping unit 81 is brought into a horizontal position while not gripping a utility pole (when gripping unit 81 is not gripping anything).As a modified example, automatic vertical control unit 105 may be configured to perform automatic vertical control only when grip determination unit 104 determines that gripping unit 81 is gripping a utility pole (target object).

The load determination unit 106 determines changes in the load acting on the gripping unit 81 based on detection information from the gripping unit load detector 125. Figure 13 is a conceptual diagram showing the relationship between the load acting on the gripping unit 81 and the displacement of the gripping unit 81 when it is moved vertically downward. As shown in Figure 13, when the gripping unit 81 is gripping a utility pole, a load corresponding to the weight of the utility pole acts downward on the gripping unit (A in the figure). When the gripping unit 81 is then 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 from the bottom of the hole (a reaction force trying to push the utility pole up). After the load on the gripping unit 81 decreases to zero (C in the figure), the direction of the load reverses from downward to upward (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 unit 81 reverses (the timing when the load becomes 0). Therefore, when the load of the gripping unit 81 detected by the gripping unit load detector 125 during the vertical descent of the gripping unit 81 while the gripping unit 81 is gripping a utility pole drops to a threshold load ("0" in this embodiment), the load determination unit 106 determines that the utility pole gripped by the gripping unit 81 has abutted against the bottom of the pole hole. Then, when the load determination unit 106 determines that the load detected by the gripping unit load detector 125 has dropped to the threshold load (the object has abutted against the bottom of the pole hole), it outputs a restriction signal to the operation control unit 102 to restrict the vertical descent operation of the gripping unit 81 (vertical descent operation). When the operation control unit 102 receives a restriction signal from the load determination unit 106, it ignores the operation signal input by operating the operating device 31 that causes the gripper 81 to vertically lower, or it blocks the control signal from the operation control unit 102 to the control valve 112 that causes the gripper 81 to vertically lower, thereby forcibly stopping the vertical lowering of the gripper 81 that had been performed up until that point. This restricts the gripper 81 from moving vertically downward any further (moving the utility pole downward). In this way, the downward movement of the gripper 81 is restricted when the lower end of the utility pole abuts against the bottom (rear end) of the pole hole, preventing the lower end of the utility pole from being pressed excessively against the hole bottom.

When the automatic pole removal switch 35 of the operating device 31 is turned on, the automatic pole removal control unit 107 operates the gripping unit 81 and the pole removal machine 40 in conjunction with each other to perform automatic pole removal work, which involves pulling an existing utility pole out of the ground. This automatic pole removal work includes a process in which the gripping unit 81 releases (relaxes) its grip on the utility pole and extends the pole removal machine 40, and a process in which the gripping unit 81 grips the utility pole and the pole removal machine 40 retracts. The automatic pole removal control unit 107 stores an automatic pole removal program. When an operation signal is input from the automatic pole removal switch 35, the automatic pole removal control unit 107 outputs a command signal to the operation control unit 102 in accordance with this program based on detection information from the gripper cylinder pressure detector 126 and the pole removal machine cylinder pressure detectors 127, 128, etc., and controls the opening and closing operation of the gripping unit 81 and the extension and retraction operation of the pole removal machine 40 in conjunction with each other to continuously perform each step of the automatic pole removal work. Details of the pole removal work (automated pole removal work) in this embodiment will be described later.

Next, a description will be given of the operation of the grip-type hole digging and pole erection vehicle 1 of this embodiment. Below, an excavation work, a pole erection work, and a pole removal work using the grip-type hole digging and pole erection vehicle 1 of this embodiment will be described in order.

[1. Excavation work]
First, we will explain the excavation work (hole digging work) of the grip-type hole digging pole erection vehicle 1. Figure 14 is a schematic diagram showing the excavation work by the auger device 20. Unless otherwise specified in the following explanation, it is assumed that the mode selection switch 33 is set to the normal mode.

When performing excavation work using the grip-type pole digger 1, first connect the auger support 17 to the tip boom 13c, then operate the operating device 31 to raise and lower the boom 13 by a predetermined angle (e.g., 60 degrees). In this state, the auger device 20 is detached from the auger storage device so that it is suspended vertically downward from the tip of the boom 13. Next, operate the operating device 31 to raise, retract, and rotate the boom 13, moving the auger screw 25 above the excavation position. Next, switch the mode selector switch 33 from normal mode to vertical auger operation mode. While rotating the auger screw 22, move the auger screw 25 vertically downward by linking the lowering and retracting of the boom 13. This allows the auger screw 25 to dig vertically into the ground. At this time, as shown in FIG. 14 , if the ground being excavated is hard, the auger screw 25 (axis J) may tilt forward, backward, left, or right relative to the vertical direction due to an excavation reaction force (excavation resistance) from the ground. The inclination angle of the auger screw 25 is constantly detected by an 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. If 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 and vertical lowering of the auger screw 25 (restricting 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 raise the auger screw 25 vertically, thereby pulling the auger screw 25 out of the ground (post hole). This allows the auger screw 25 to return to a state where 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.

[2. Pole erection work]
Next, the pole erection operation of the grip-type hole-digging pole erection vehicle will be described. Figure 15 is a schematic diagram showing the operation of the gripper 81 when the automatic vertical switch 34 is operated, and Figure 16 is a schematic diagram for explaining the direction of the load acting on the gripper 81. Unless otherwise specified in the following description, it is assumed that the mode selector switch 33 is set to the normal mode.

When performing pole erection work using the gripping-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 unit 81 is swung vertically, horizontally, and rotated, etc., to move the gripping unit 81 close to a utility pole (e.g., a utility pole placed horizontally at a work site) and align the gripping unit 81 with the utility pole. Next, the pair of gripping claws 82 are operated in the closing direction (closing operation), causing the gripping unit 80 to grip the utility pole. Note that while the gripping unit 81 is gripping the utility pole in this manner, the gripping unit load detector 125 constantly detects the load acting on the gripping unit 81, and this detection signal is input to the controller 100. Next, the boom 13 and the gripping device 50 are operated appropriately to lift the utility pole gripped by the gripping unit 81 and move it above the pole erection hole (the pole erection hole excavated in the excavation work described above). Above this pole hole, the worker operates the operating device 31 to visually bring the utility pole closer to a vertical position, as shown in FIG. 15(A). Once the utility pole has been brought to a vertical position to a certain extent, 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 123, it determines that the tilt angle of the gripper 81 is within a predetermined angle and outputs a command signal to the operation control unit 102. Upon receiving the command signal from the automatic vertical control unit 105, the operation control unit 102, based on the detection information from the gripper tilt angle detector 124, extends and retracts the vertical swing cylinder 62 to correct the forward/backward tilt of the gripper 81 and rotates the gripper motor 79 to correct the left/right tilt of the gripper 81, thereby bringing the gripper 81 to a horizontal position. As a result, the utility pole gripped by the gripper 81 can be brought to a vertical position, as shown in FIG. 15(B). Furthermore, if the position (front, back, left, or right) of the utility pole in a vertical position is misaligned with the position of the post hole, the boom 13 can be extended and rotated to move the utility pole horizontally (front, back, left, and right) while maintaining it in a vertical position, so that the utility pole can be positioned directly above the post hole.

Next, to move the vertically positioned utility pole vertically downward toward the pole hole, the mode selector switch 33 is operated to switch from normal mode to vertical gripper operation mode. As shown in Figure 16 (A), when the gripper 81 is gripping a vertically positioned utility pole, a load corresponding to the weight of the pole acts downward on the gripper 81. After switching the mode selector switch 33 to vertical gripper operation mode, the boom 13's hoisting and extension operations are linked with the vertical swing of the gripper 81 in response to operation of the boom rotation/hoisting control lever 32a, moving the gripper 81 vertically downward. This inserts the utility pole gripped by the gripper 81 into the pole hole. As the gripper 81 is moved vertically downward, when the lower end of the utility pole gripped by the gripper 81 abuts against the bottom of the pole hole, the gripper 81 receives a ground reaction force (a force pushing up the utility pole) from the bottom of the hole via the utility pole. As a result, as shown in FIG. 16(B), the load acting on the gripping portion 81 reverses from downward to upward. At this time, when the load acting on the gripping portion 81 becomes zero, the load determination portion 106 of the controller 100 outputs a restriction signal to the operation control portion 102, causing the gripping portion 102 to stop moving vertically downward. As a result, the vertical downward movement of the gripping portion 81 (the utility pole) stops the moment the lower end of the utility pole abuts against the bottom of the pole hole, and the utility pole is positioned relative to the pole hole. After inserting the utility pole all the way to the bottom of the pole hole, the lower end of the utility pole can be buried and compacted in the pole hole by filling the gap between the pole and the hole with soil or sand (by backfilling excavated soil or broken rock, etc.). This completes the pole installation work of installing the utility pole in the pole hole.

[3. Pillar removal work]
Next, we will explain the pole extraction work (automatic pole extraction work) by the grip-type hole digging pole erection vehicle 1. Figures 17 to 19 are schematic diagrams showing the flow of the automatic pole extraction work.

First, to perform automatic pole removal work, as shown in Figure 17(A), as preparation for the work, the pole removal machine 40 is placed near the base of the existing utility pole to be removed (designated "P" in Figures 17-19). The chain 45 of this pole removal machine 40 is wrapped around the pole several times, and both ends of the chain 45 are engaged with the upper end of the pole removal machine cylinder 41. The hydraulic hoses 46 and 47 (see Figure 10) of the pole removal machine cylinder 41 are then connected to the vehicle's hydraulic outlet, and the pole removal machine cylinder 42 is then connected to the electromagnetic proportional control valve V10. The operating device 31 is then operated to move the gripping unit 81 near the center of gravity of the utility pole, and the gripping unit 81 is then closed to grip the center of gravity of the utility pole. This completes the preparation for the work.

After completing the preliminary preparations for the work, the worker turns on the automatic pole removal switch 35 of the operating device 31. This causes the automatic pole removal control unit 107 of the controller 100 to start the automatic pole removal work in accordance with a pre-stored automatic pole removal program. First, upon receiving an operation signal from the automatic pole removal switch 35, the automatic pole removal control unit 107 outputs a command signal to the operation control unit 102, which extends the gripper cylinder 99 and operates the gripping unit 81 (gripping claws 82) in the opening direction. This temporarily loosens the grip of the pole by the gripping unit 81, as shown in FIG. 17(B) . This opening operation (release operation) of the gripping unit 81 is performed by operating the pair of gripping claws 82 in directions that move them apart from each other, to the extent that the pole does not come off the gripping unit 81, thereby weakening the gripping force of the gripping unit 81 on the pole (at this time, a small gap may be formed between the gripping claws 82 and the pole). Furthermore, this operation of the gripping portion 81 in the opening direction (extension of the gripper cylinder 99) continues until the pressure detected by the gripper cylinder pressure detector 126 (pressure in the rod side oil chamber of the gripper cylinder 99) becomes less than the second threshold pressure.

The automatic pole extraction control unit 107 then outputs a command signal to the operation control unit 102 to extend the pole extraction machine cylinder 41, as shown in Figure 17 (C). Extending the pole extraction machine cylinder 41 places the chain 45 of the pole extraction machine 40 in a tensile state (tightly binding the utility pole), and the utility pole is pulled out of the ground in response to the extension of the pole extraction machine cylinder 41.

The automatic column extraction control unit 107 then determines whether the column extractor cylinder 41 has reached its fully extended state (stroke end in the extension direction). Based on detection information from the column extractor cylinder pressure detector 127, the automatic column extractor control unit 107 determines that the column extractor cylinder 41 has reached its stroke end in the extension direction (fully extended state) when the pressure in the bottom oil chamber of the column extractor cylinder 41 exceeds a predetermined pressure (maximum pressure). When the automatic column extractor control unit 107 determines that the column extractor cylinder 41 has reached its fully extended state (stroke end in the extension direction), it outputs a command signal to the operation control unit 102, which stops the extension operation of the column extractor cylinder 41 and holds the column extractor cylinder 41 in its fully extended state for a predetermined time (e.g., 1 second), as shown in Figure 18 (D).

Next, the automatic pole removal control unit 107 outputs a command signal to the operation control unit 102 to contract the gripper cylinder 99 and operate the gripping unit 81 (gripping claws 82) in the closing direction. As a result, the utility pole is gripped by the gripping unit 81, as shown in Fig. 18(E) . This operation of the gripping unit 82 in the closing direction (the contraction operation of the gripper cylinder 99) continues until the pressure detected by the gripper cylinder pressure detector 126 (the pressure in the rod -side oil chamber of the gripper cylinder 99) becomes equal to or greater than the first threshold pressure (until the gripping force of the gripping unit 81 reaches a specified gripping force).

The automatic pole extraction control unit 107 then outputs a command signal to the operation control unit 102 to cause the pole extraction machine cylinder 41 to retract, as shown in Figure 18 (F). By retracting the pole extraction machine cylinder 41, the tension on the chain 45 is gradually released, and the pole extraction machine cylinder 41 can be retracted while the pole is held by the gripping portion 81 (holding the pole so that it does not fall).

Next, the automatic pole extraction control unit 107 determines whether the pole extractor cylinder 41 has reached a fully retracted state (retraction stroke end). Based on detection information from the pole extractor cylinder pressure detector 128, the automatic pole extraction control unit 107 determines that the pole extractor cylinder 41 has reached a fully retracted state (retraction stroke end) when the pressure in the rod-side oil chamber of the pole extractor cylinder 41 exceeds a predetermined pressure (maximum pressure). When the automatic pole extraction control unit 107 determines that the pole extractor cylinder 41 has reached a fully retracted state (retraction stroke end), it outputs a command signal to the operation control unit 102, which stops the retraction operation of the pole extractor cylinder 41 and maintains the pole extractor cylinder 41 in a fully retracted state, as shown in FIG. 19 (G). Then, when the operator confirms that the base of the utility pole is loose, the automatic pole extraction operation is terminated by turning off the automatic pole extraction switch 35 of the operating device 31, which completes one cycle of the operations up to that point.

Once the automatic pole extraction work is complete, the pole extraction machine 40 is removed from the utility pole, as shown in Figure 19(H). Next, as shown in Figure 19(I), the worker operates the operating device 31 to appropriately operate the boom 13 and gripping device 50, and moves the gripping part 81 upward, thereby lifting the utility pole gripped by the gripping part 81 out of the pole hole and moving it to the predetermined location. Then, after the utility pole has been lowered to the predetermined location, the gripping claws 82 are operated in the opening direction, releasing the grip of the utility pole by the gripping part 81, allowing the utility pole to be placed in the predetermined location.

Although not shown, if the automatic pole removal switch 35 is not switched from ON to OFF within a predetermined time (e.g., 10 seconds) after the first cycle of the automatic pole removal operation is completed, the second cycle of the automatic pole removal operation will begin (the operation can continue to the third cycle and beyond if the automatic pole removal switch 35 is not switched from ON to OFF). In other words, if the pole cannot be removed with just one cycle of the automatic pole removal operation (if the base of the pole does not loosen), the second cycle of the automatic pole removal operation will automatically begin if the automatic pole removal switch 35 is left ON (the automatic pole removal operation will be automatically repeated). In addition, during the second and subsequent cycles of the automatic pole removal operation, to prevent the pole to be removed from falling from the gripper 81, the gripper 81 is held closed until the detected pressure of the pole removal machine cylinder pressure detector 127 (the pressure in the bottom oil chamber of the pole removal machine cylinder 41) reaches a predetermined value. When this detected pressure reaches a predetermined value, the gripper 81 is opened. In other words, in the first cycle of the automatic pole removal operation described above, the gripping unit 81 was opened (the gripping by the gripping unit 81 was loosened) before the pole removal machine cylinder 41 began to extend. However, in this second cycle, the pole removal machine cylinder 41 begins to extend first, and then the gripping unit 81 is opened (the gripping is loosened) after the detected pressure of the pole removal machine cylinder pressure detector 127 reaches a predetermined value, thereby preventing the pole from falling during removal.

The main effects achieved by this embodiment can be summarized as follows:

First, according to this embodiment, if the auger screw 25 tilts forward, backward, left, or right beyond the allowable angle relative to the vertical, the operation of the boom 13 and the auger screw 25 can be restricted to automatically stop the excavation work of the auger screw 25. This makes it possible to prevent the formation of a pole hole for erecting a utility pole at an angle relative to the vertical.

Furthermore, according to this embodiment, when the gripping portion 81 is moved downward to insert the utility pole gripped 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. This prevents the worker from continuing to move the gripping portion 81 downward without realizing that the lower end of the utility pole has come into contact with the bottom of the hole (which would cause the lower end of the utility pole to be pressed excessively against the bottom of the hole), and makes it possible to prevent an excessive load from being applied to the gripping portion 81 or the utility pole, which could cause damage.

Furthermore, according to this embodiment, when the automatic vertical switch 34 is operated, the vertical oscillating cylinder 62 and gripper motor 79 are activated to change the attitude of the gripping unit 81 in accordance with the inclination angle of the gripping unit 81 relative to the horizontal plane detected by the gripping unit inclination angle detector 124, thereby enabling the utility pole held by the gripping unit 81 to be held in a vertical position along the vertical direction. Therefore, even on sloping ground such as mountainous regions, the utility pole held by the gripping unit 81 can be automatically held in a vertical position without the need for skilled operation, making it possible to dramatically improve the work efficiency of pole erection work.

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

Furthermore, according to this embodiment, there is no need to use large heavy machinery such as a crane to lift the utility pole to be removed. The gripping device 50 of this gripping-type hole-digging pole-setting vehicle 1 can be used to appropriately switch between gripping and releasing (relaxing the grip) the utility pole to be removed, allowing the pole removal work to be performed using the pole extraction machine 40. Therefore, different types of work (pole installation work and pole removal work) can be performed with a single gripping-type hole-digging pole-setting vehicle 1, expanding the uses of the gripping device 50 and further increasing the added value of this gripping-type hole-digging pole-setting vehicle 1.

In addition, in this embodiment, a series of pole removal operations can be performed automatically and continuously through linked operations that combine the opening and closing operation of the gripping portion 31 with the extension and retraction operation of the pole removal tool 40, thereby reducing the effort and burden on the worker and improving the efficiency and safety of the pole removal operation.

In addition, in this embodiment, even if the pole cannot be removed with a single extension/retraction operation of the pole removal machine 40, the pole removal machine 40 can be automatically and continuously extended and retracted multiple times in response to the operation of the automatic pole removal switch 35, thereby further improving the work efficiency of the pole removal work.

The present invention is not limited to the above-described embodiments, and modifications can be made as appropriate without departing from the spirit of the present invention.

In the above embodiment, the gripper load detector 125 is configured as 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 gripper load detector 125 may be configured as a pressure detector that detects the pressure of the hydraulic oil supplied to the bottom-side oil chamber and/or rod-side oil chamber of the vertical swing cylinder 62.

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, a load cell or strain gauge may be provided inside the gripping claws 82 to directly detect the gripping force of the gripping portion 81.

In the above embodiment, the stroke end in the extension/retraction direction of the column extractor cylinder 41 was detected by the pressure in the bottom-side oil chamber and rod-side oil chamber of the column extractor cylinder 41, but this configuration is not limited to this. For example, it may be configured with a stroke detector that detects the position (stroke position) in the extension/retraction direction of the piston rod 43 of the column extractor cylinder 41.

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. For example, the operating device 31 may be configured as a wired or wireless remote control operating device (portable operating device).

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

DESCRIPTION OF SYMBOLS 1 Gripper-type hole digging pole vehicle 2 Vehicle body 12 Swivel base 13 Boom 20 Auger device 22 Auger motor 25 Earth auger 31 Operating device 33 Mode selection switch 34 Automatic vertical switch 35 Automatic pole extraction switch 40 Pole extraction machine 41 Pole extraction machine cylinder 50 Gripper device 51 Arm 55 Arm cylinder 60 First joint member 62 Vertical swing cylinder 70 Second joint member 71 Horizontal swing cylinder 79 Gripper motor 80 Gripper 81 Gripper unit 82 Gripper claws 99 Gripper cylinder 100 Controller 101 Position calculation unit 102 Operation control unit 103 Auger inclination determination unit 104 Grip determination unit 105 Automatic vertical control unit 106 Load determination unit 107 Automatic pole extraction control unit 123 Auger inclination angle detector 124 Gripper inclination angle detector 125 Gripper load detector 126 Gripper cylinder pressure detector 127 Pillar removal machine cylinder pressure detector 128 Pillar removal machine cylinder pressure detector

Claims (2)

a boom provided on the vehicle body so as to be capable of raising and lowering and extending;
a gripping portion capable of gripping a columnar object;
a support mechanism provided between the tip of the boom and the gripping part, which changes the attitude of the gripping part with respect to the tip of the boom;
an operating device for operating the boom, the gripping portion, and the support mechanism;
a load detector that detects a load acting on the gripping portion when the gripping portion is gripping a columnar object;
an operation control unit that controls the operation of the boom, the gripping unit, and the support mechanism in response to an operation of the operation device;
A control device for a gripping-type hole-digging pole-setting vehicle, characterized in that it is configured with an operation control unit that regulates the downward movement of the gripping part by the boom and the support mechanism when the load detected by the load detector drops below a predetermined threshold value when the operation control unit operates the boom and the support mechanism to move the gripping part holding a pillar-shaped object downward. the operating device includes a gripper vertical actuation operating device that is operated to move the gripper in a vertical direction,
the operation control unit controls the vertical movement of the gripper by linking the raising and lowering operation and the extension and contraction operation of the boom with the operation of the support mechanism in response to the operation of the gripper vertical operation operation device,
The control device for a gripping-type hole-digging and pole-setting vehicle as described in claim 1, characterized in that the operation regulating unit regulates the vertical downward movement of the gripping unit by the boom and the support mechanism when the load detected by the load detector drops below the threshold value when the operation control unit operates the boom and the support mechanism to move the gripping unit gripping a pillar-shaped object vertically downward.