Safety apparatus of gripping-type pole construction truck

Abstract

To provide a safely apparatus of a gripping-type pole construction truck capable of safely working regardless of the gripping position of an object.SOLUTION: A safety apparatus of a gripping-type pole construction truck comprise a derricking cylinder 16 for derricking a boom, an arm cylinder 55 to make an arm vertically oscillate with respect to a boom tip, a vertical oscillating cylinder 62 to make a gripping part vertically oscillate with respect to an arm tip, a moment calculation part 103 to calculate the moment around an arm oscillating fulcrum in the gripping state of an object due to the gripping part, and a regulation part 105 to regulate the actuation of the vertical oscillating cylinder 62 when the calculated moment in the moment calculation part 103 exceeds a preset regulation moment.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a safety device for a gripping type pile-driving vehicle with a gripping part for gripping a columnar object such as a utility pole.

Background Art

[0002] As a pile-driving vehicle which is one type of work vehicle, there is known a gripping type pile-driving vehicle provided with a swivel base rotatably provided on a vehicle body, a boom provided on the swivel base so as to be able to move up and down and extend and contract, an auger device attached to the boom for excavating a pile-driving hole for driving a utility pole, and a gripping device provided at the tip of the boom for gripping a columnar object such as a utility pole (for example, see Patent Document 1). When excavating a pile-driving hole in the ground using such a gripping type pile-driving vehicle, 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, whereby a pile-driving hole having a predetermined depth can be formed. After the excavation of this pile-driving hole is completed, the auger device is pulled up and stored on the side of the boom, and the utility pole is gripped by a gripping part provided on the gripping device so as to be able to open and close, and the boom is appropriately operated in a state of gripping this utility pole, whereby the utility pole can be directly driven into the excavated pile-driving hole. In such a gripping type pile-driving vehicle, a series of pile-driving operations can be efficiently performed as compared with the case where the utility pole is suspended and the work is performed using a winch or a crane.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When gripping a utility pole (long object) with the gripping part of the gripping device, it is desirable to grip the pole at its center of gravity. However, it is not easy for an operator to visually determine the center of gravity of a utility pole, so the gripping position of the utility pole may deviate from the center of gravity. In such cases, when the gripping part is activated to rotate the orientation of the utility pole, the weight of the utility pole generates an excessive moment around the tip of the boom, and there is a problem that this overload may cause damage to the gripping device or other structures.

[0005] This invention has been made in view of the above problems, and aims to provide a safety device for a gripping-type hole-digging and pole-erecting vehicle that can operate safely regardless of the gripping position of the object. [Means for solving the problem]

[0006] To solve the above problems, the safety device for a gripping-type hole-digging pole-erecting vehicle according to the present invention is characterized by comprising: a boom mounted on the vehicle body so as to be able to be raised and lowered; an arm mounted at the tip of the boom so as to be able to swing along the luffing surface of the boom; a gripping part mounted at the tip of the arm so as to be able to swing along the luffing surface and capable of gripping an object; a boom luffing actuator for raising and lowering the boom; an arm actuator for swinging the arm along the luffing surface relative to the tip of the boom; a gripping part actuator for swinging the gripping part along the luffing surface relative to the tip of the arm; a moment detection unit for detecting a moment acting around the pivot point of the arm when an object is gripped by the gripping part; and a regulating unit for regulating the operation of the gripping part actuator when the moment detected by the moment detection unit exceeds a preset regulating moment.

[0007] In the safety device for the gripping-type hole-digging pole-erecting vehicle with the above configuration, it is preferable that the restricting unit also restricts the operation of the boom luffing actuator when the moment detected by the moment detection unit exceeds the restricting moment.

[0008] Furthermore, in the safety device for the gripping-type hole-digging pole-erecting vehicle with the above configuration, it is preferable that the device includes an inclination angle detection unit for detecting the inclination angle of the gripping portion with respect to the horizontal plane, and that the regulating unit, when the moment detected by the moment detection unit exceeds the regulating moment, allows the operation of the gripping portion actuator to swing the gripping portion in the direction that decreases the inclination angle, and restricts the operation of the gripping portion actuator to swing the gripping portion in the direction that increases the inclination angle, based on the detection information of the inclination angle detection unit. [Effects of the Invention]

[0009] According to the safety device for the gripping-type hole-digging pole-erecting vehicle of the present invention, when the moment around the pivot point of the arm exceeds a preset regulated moment, the operation of the gripping cylinder is restricted. This allows the gripping part to swing properly and safely, regardless of the gripping position of the object (utility pole) by the gripping part. This prevents damage to structures such as the arm and gripping part due to the generation of excessive moments, thereby improving safety during operation.

[0010] Furthermore, in the safety device for the gripping-type hole-digging pole-erecting vehicle according to the present invention, when the moment around the pivot point of the arm exceeds a preset regulated moment, the operation of the boom luffing cylinder is also restricted along with the operation of the gripping cylinder. This reliably prevents damage to structures such as the arm and gripping section due to the generation of excessive moments, thereby further improving work safety.

[0011] Furthermore, in the safety device for the gripping-type hole-digging pole-erecting vehicle according to the present invention, if the moment around the pivot point of the arm exceeds the regulated moment, the gripping cylinder will not activate even if it is accidentally operated in an unsafe direction (a direction in which the moment increases), and the gripping cylinder will only activate when it is operated in a safe direction (a direction in which the moment decreases). Therefore, even if the moment reaches the regulated moment and the operation restriction is activated, the operator can safely swing the gripping part without getting stuck (making it easier to operate quickly when the operation restriction is activated), thus achieving both safety and workability. [Brief explanation of the drawing]

[0012] [Figure 1] This is a side view of the gripping type hole-digging and pole-erecting vehicle according to this embodiment. [Figure 2] The above is a plan view of the gripping-type hole-digging and pole-erecting vehicle. [Figure 3] This is a side view showing the usage of the gripping-type hole-digging and pole-erecting vehicle described above. [Figure 4] This is a perspective view of the gripping device provided on the gripping-type hole-digging and pole-erecting vehicle described above. [Figure 5] This is a perspective view of the main part of the gripping device shown above, taken from the right. [Figure 6] This is a perspective view of the main part of the gripping device shown above, taken from the left. [Figure 7] This is a cross-sectional view of the gripping device described above. [Figure 8] This is a longitudinal cross-sectional view of the gripping device described above. [Figure 9] The above is a functional block diagram of the gripping-type hole-digging and pole-erecting vehicle. [Figure 10] This is a perspective view showing the gripping device gripping a utility pole. [Figure 11] This is a schematic diagram illustrating the restricted and permitted directions for the vertical swivel operation of the gripping device described above. [Figure 12] This is a perspective view showing the gripping device gripping a utility pole at a point away from its center of gravity. [Modes for carrying out the invention]

[0013] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. First, in this embodiment the overall configuration of the gripping type hole-drilling pile driving vehicle 1 according to this embodiment will be described with reference to FIGS. 1 to 3.

[0014] As shown in FIG. 1, the gripping type hole-drilling pile driving vehicle 1 is configured based on a truck vehicle having a cab 7 at the front of the vehicle body 2 and capable of traveling by a pair of left and right tire wheels 5 arranged before and behind the vehicle body 2. Jacks 9 for lifting and supporting the vehicle body 2 are arranged at four locations 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 therein to extend downward, thereby making the entire vehicle body 2 in a stable state. The operation of the jack 9 is performed by operating a jack operating device (not shown) provided at the rear of the vehicle body 2.

[0015] In the mounting area behind the cab 7 in the vehicle body 2, a turntable 12 driven by a swivel motor 14 (see FIG. 9) and configured to be horizontally swiveling around a vertical axis is provided. The base end of the boom 13 is attached to the turntable 12 so as to be swingable (up and down freely) in the vertical direction.

[0016] The boom 13 has a configuration in which a base end boom 13a, an intermediate boom 13b, and a tip boom 13c are nested and combined in order from the turntable 12 side, and the boom 13 can be extended and contracted in the axial direction (longitudinal direction) by the extension and contraction drive of a telescopic cylinder 15 (see FIG. 9) provided therein. Further, a lifting cylinder 16 is straddled between the base end boom 13a and the turntable 12, and by driving the lifting cylinder 16 to extend and contract, the entire boom 13 can be lifted and lowered within the upper and lower surfaces (vertical plane).

[0017] An auger device 20 for excavating holes for erecting pillars is attached to the boom 13 via an auger support 17 that can be selectively connected to the base boom 13a and the tip boom 13c. The auger device 20 consists of an auger motor 21 with a reduction gear and an earth auger 22 that rotates around an axis by rotationally driving the auger motor 21. An auger storage device 18 is also provided on the side of the base boom 13a to hold the auger device 20 in a stored state. The auger device 20 is mounted on the auger support 17 so as to be able to swing up and down in a vertical plane, and can swing between a stored position where the auger device 20 is stored along the side of the base boom 13a by the auger storage device 18 and a working position where the auger device 20 is detached from the auger storage device 18 and the earth auger 22 is in a position approximately vertical to the ground.

[0018] When using the auger device 20, as shown in Figure 3I, the auger support 17 is connected to the tip boom 13c, and the auger device 20, which has been detached from the auger storage device 18, is swung to the working position (with the earth auger 22 in a position approximately perpendicular to the ground). By rotating the earth auger 22 and coordinating the tilting and retracting movements of the boom 13, the auger device 20 is moved linearly downward, enabling the excavation of pole holes. On the other hand, when the auger device 20 is not in use, as shown in Figure 3II, the auger support 17 is connected to the base boom 13a, and the auger device 20 is stored and held in a storage position along the side of the base boom 13a by the auger storage device 18. When the auger device 20 is in the storage position, various operations such as pole erection (indicated by the symbol P in Figure 3; the same applies hereafter) and obstacle relocation can be performed using the gripping device 50 described later.

[0019] A boom head 19 is fixed to the tip of the tip boom 13c. A gripping device 50 for gripping objects (columnar objects) such as utility poles P or trees is attached to this boom head 19. The configuration of this gripping device 50 will be explained with additional reference to Figures 4 to 8. Note that in Figures 7 to 8, hatching indicating cross-sections has been omitted for clarity. Also, for the sake of explanation, the orientation of the gripping device 50 shown in Figure 4 will be used as the reference point, and the directions of the arrows indicating front / back, left / right, and up / down will be referred to as the front / back direction, left / right direction, and up / down direction.

[0020] The gripping device 50 comprises an arm 51 attached to the boom head 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 (vertical pivot) in the vertical direction, a second joint member 70 attached to the first joint member 60 so as to be able to swing (lateral pivot) in the left-right direction, and a gripper 80 rotatably attached to the second joint member 70. In this embodiment, the arm 51, the first joint member 60, the second joint member 70, the vertical pivot cylinder 62, the horizontal pivot cylinder 71, the gripper motor 79, etc., constitute a support mechanism that changes the posture of the gripping portion 81 of the gripper 80.

[0021] The arm 51 is pivotally connected to the boom head 19 at one end in the axial direction (longitudinal direction) via a connecting pin 52, and its other end in the axial direction (longitudinal direction) is pivotally connected to the first joint member 60 via a connecting pin 53. An arm cylinder 55 is mounted between the boom head 19 and the first joint member 60. The rod end of the arm cylinder 55 is pivotally connected to the boom head 19 via a connecting pin 56. The bottom end of the arm cylinder 55 is pivotally connected to the first joint member 60 via a connecting pin 57. By extending and retracting this arm cylinder 55, the arm 51 is configured to swing freely (flex and extend freely) in the vertical direction around the connecting pin 52 relative to the boom head 19.

[0022] 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 this 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 end of the vertical swivel cylinder 62 is pivotally connected to the base end of the arm 51 via a connecting pin 63. The rod end of the vertical swivel 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 swivel cylinder 62, the first joint member 60 is configured to swing freely in the vertical direction (vertical swivel) relative to the arm 51 around the connecting pin 53.

[0023] The second joint member 70 is supported by the first joint member 60, sandwiched between it from above and below. A lateral swivel cylinder 71 is provided at the upper end of the first joint member 60. The bottom end of the lateral 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 lateral swivel cylinder 71, the second joint member 70 is configured to swing freely (swivel freely) in the left-right direction around the connecting pin 61 relative to the first joint member 60.

[0024] 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 for opening and closing the gripping portion 81.

[0025] The gripping section 81 comprises 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 be opened and closed in directions that bring them closer together or further apart (opening and closing directions). The gripping claws 82 are configured to grip various objects (columnar objects) such as utility poles P 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. The tips of the gripping claws 82 have alternating notches 82a and 82b, and these tips are configured to intersect (overlap) with each other. The support plates 83 are provided with a flat upper bracket 85 for detachably attaching an attachment (not shown) (for example, a tree felling device for felling trees).

[0026] The gripper housing 86 is connected to the upper and lower support plate portions 83 and the second joint member 70 It comprises a support cylinder portion 87 that is rotatably supported, and a cylinder bracket portion 92 that is fixed to the base end side of the support cylinder portion 87 and disposed between the first joint member 60 and the second joint member 70.

[0027] The support cylinder portion 87 has a double structure, comprising an inner cylinder portion 88 formed in the shape of a hollow rectangular tube, and an outer cylinder portion 89 formed in the shape of a hollow cylindrical tube and provided on the outer circumference of the inner cylinder portion 88. A sliding member 95 of the opening / closing mechanism 93, described later, is mounted on the inner circumference of the inner cylinder portion 88 so as to be slidable in the front-rear direction. A worm wheel 90 is mounted on the outer circumference of the outer cylinder portion 89 concentrically with the outer cylinder portion 89. This worm wheel 90 meshes with a worm pinion 91 that is rotatably supported inside the second joint member 70. A gripper motor 79 is mounted on the upper end of the second joint member 70, and the worm pinion 91 is connected to the output shaft of this gripper motor 79 via a reduction gear. When this 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 7) 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 predetermined direction around the rotation axis X (see Figure 7) via the worm pinion 91 and worm wheel 90. In the orientation of the gripping device 50 shown in Figure 4, the rotation axis X direction of the gripper 80 (gripping part 81) corresponds to the front-rear direction, and the opening and closing direction (gripping direction) of the gripping part 81 corresponds to the left-right direction.

[0028] The opening / closing mechanism 93 comprises a pair of link members 94, a sliding member 95 linked 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 other ends of the pair of link members 94 are also pivotally connected to the tip of the sliding member 95 via a connecting pin 97, with the other ends of each link member 94 overlapping vertically. The sliding member 95 is inserted into the hollow part of the inner cylindrical portion 88 and is mounted so as to be slidable (reciprocal) along the inner circumferential surface of the inner cylindrical portion 88. A slider 98 made of synthetic resin 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. As a result, the gripping claws 82 swing in the opening direction around the connecting pin 84 as a pivot (the gripping claws 82 operate in the opening direction), releasing the grip on 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 towards each other. As a result, the gripping claws 82 swing in the closing direction around the connecting pin 84 as a pivot (the gripping claws 82 operate in the closing direction), gripping the object. The opening and closing mechanism 93 is configured symmetrically, so the pair of gripping claws 82 open and close symmetrically.

[0029] On the side of the turntable 12 in the vehicle body 2, there is an operator's seat 30 for operating each work device (turntable 12, boom 13, auger device 20, gripping device 50). In front of this operator's seat 30, there is an operating device 31 that can be operated by an operator while seated. As shown in Figure 9, the operating device 31 includes a boom turntable / luffing operation lever 32a for turning and luffing the boom 13, a boom extension / retraction / flexing operation lever 32b for extending and retracting the boom 13 and bending the arm 51, an auger operation lever 32c for rotating the auger screw 25, a gripping unit vertical swing operation lever 32d for vertical swing operation of the gripping unit 81, a gripping unit lateral swing operation lever 32e for horizontal swing operation of the gripping unit 81, a gripping unit rotation operation lever 32f for rotation operation of the gripping unit 81, and a gripping unit A gripping lever 32g for opening and closing the 81 is provided.

[0030] Furthermore, as shown in Figure 9, the operating device 31 is provided with a mode selection switch 33. The mode selection switch 33 is a toggle switch that can be switched to either the neutral position or the tilted position (it is configured to retain the switched operating position even if the operator releases their hand). When the mode selection switch 33 is selected to the neutral position, the normal mode is set, and when the mode selection switch 33 is selected to the tilted position, the gripping unit vertical operation mode is set. The normal mode is a mode in which each hydraulic actuator is operated independently in response to the operation of each operating lever 32a to 32g, allowing for individual luffing, extension, and slewing of the boom 13, rotation of the auger device 20 (auger screw 25), bending and extending of the arm 51, and vertical swivel, horizontal swivel, rotation, and opening / closing of the gripping unit 81. The gripping unit vertical operation mode is a mode in which the luffing cylinder 16, the telescopic cylinder 15, and the vertical swivel cylinder 62 are operated in combination (interlocked operation) in response to the operation of the boom slewing and luffing operation lever 32a, thereby moving the gripping unit 81 in the vertical direction (up and down direction).

[0031] Here, the operating mechanisms of the turntable 12, boom 13, auger device 20, gripping device 50, etc., as shown in Figure 9, are configured with a controller 100 that receives operating signals from the operating device 31 and controls the turntable motor 14, telescopic cylinder 15, luffing cylinder 16, auger motor 22, arm cylinder 55, vertical swivel cylinder 62, horizontal swivel cylinder 71, gripper motor 79, and gripper cylinder 99 (hereinafter collectively referred to as "hydraulic actuators"), and a hydraulic unit 110 that supplies hydraulic fluid to drive these hydraulic actuators.

[0032] The operation signal output by the operation of 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).

[0033] The hydraulic unit 110 comprises a hydraulic pump 111 that discharges hydraulic fluid and control valves 112 that control the direction and amount of hydraulic fluid supplied from the hydraulic pump 111 to each hydraulic actuator. The hydraulic pump 111 is driven by power taken from the vehicle's 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 corresponding to the telescopic cylinder 15, an electromagnetic proportional control valve V3 corresponding to the luffing 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 swivel cylinder 62, an electromagnetic proportional control valve V7 corresponding to the horizontal swivel cylinder 71, an electromagnetic proportional control valve V8 corresponding to the gripper motor 79, and an electromagnetic proportional control valve V9 corresponding to the gripper cylinder 99. Based on command signals from the controller 100, the control valve 112 electromagnetically drives the spools of each electromagnetic proportional control valve V1 to V9 to control the supply direction and amount of hydraulic fluid 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 turntable 12, boom 13, auger device 20, and gripping device 50).

[0034] Next, the safety device provided in the gripping-type hole-digging pole-erecting vehicle 1 of this embodiment will be described. As shown in Figure 9, the safety device of this embodiment mainly consists of a boom luffing angle detector 120, a boom extension amount detector 121, a boom slewing angle detector 122, an arm bending and extension angle detector 123, a gripping part inclination angle detector 124, an arm cylinder axial force detector 125, and a controller 100.

[0035] The boom luffing angle detector 120 is located inside the base boom 13a and detects the luffing angle θ1 of the boom 13. The boom extension amount detector 121 is located at the base end of the base boom 13a and detects the length (extension amount) L of the boom 13. The boom slewing angle detector 122 is located on the vehicle body 2 and detects the slewing angle θ2 of the boom 13 (slewing body 12). The arm bending angle detector 123 is located near the connection point (connecting pin 52) between the boom head 19 and the arm 51 and detects the bending angle (swing angle) φ of the arm 51 relative to the boom head 19. These four detectors 120 to 123 output voltage signals (detection signals) to the controller 100 according to the information they detected (boom luffing angle θ1, extension amount L, slewing angle θ2, and arm bending angle φ of the arm 51).

[0036] The gripping section tilt angle detector 124 is mounted on the upper surface of the gripping section 81 (support plate section 83). This gripping section tilt angle detector 124 is a uniaxial tilt angle detector that detects the tilt angle Ψ of the gripping section 81 in the front-rear direction with respect to the horizontal plane. This gripping section tilt angle detector 124 detects the tilt angle Ψ of the gripping section 81 in the front-rear direction and outputs a voltage signal (detection signal) corresponding to the detected tilt angle Ψ to the controller 100.

[0037] The arm cylinder axial force detector 125 is a pin-type load cell installed on the connecting pin 56 (see Figure 10) that pivotally connects the boom head 19 and the rod-side end of the arm cylinder 55. This arm cylinder axial force detector 125 detects the axial force F of the arm cylinder 55 (the axial load acting from the arm cylinder 55 to the connecting pin 56) and outputs a voltage signal (detection signal) corresponding to the detected axial force F to the controller 100.

[0038] The controller 100 includes a position calculation unit 101, an operation control unit 102, a moment calculation unit 103, a moment comparison unit 104, and a regulating unit 105.

[0039] The position calculation unit 101 calculates the position of the tip of the boom 13 relative to the vehicle body 2 based on the detection information from the boom luffing angle detector 120, the boom extension amount detector 121, and the boom slewing angle detector 122 (the luffing angle θ1, extension amount L, and slewing angle θ2 of the boom 13).

[0040] The operation control unit 102 controls the operation of each actuator according to the operation signal (operation command) output from the operating device 31, based on the operation mode selected by the mode selection switch 33. The operation modes will be described below.

[0041] When the mode selection switch 33 is selected for normal mode, the operation control unit 102 operates each hydraulic actuator independently in response to the operation of each operation lever 32a to 32g. Specifically, when the boom slewing / luffing operation lever 32a is tilted forward (in the forward, backward, left, and right directions relative to the operator operating it; the same applies hereinafter), the luffing cylinder 16 is retracted to lower the boom 13, and when the boom slewing / luffing operation lever 32a is tilted backward, the luffing cylinder 16 is extended to raise the boom 13. Also, when the boom extension / bending operation lever 32b is tilted forward, the extension cylinder 15 is extended to extend the boom 13, and when the boom extension / bending operation lever 32b is tilted backward, the extension cylinder 15 is retracted to retract the boom 13. Furthermore, when the boom slewing / luffing lever 32a is tilted to the left, the slewing motor 14 is operated in the forward direction to slewing the boom 13 counterclockwise, and when the boom slewing / luffing lever 32a is tilted to the right, the slewing motor 14 is operated in the reverse direction to slewing the boom 13 clockwise. Furthermore, when the auger operation lever 32c is tilted forward, the auger motor 22 is operated in the reverse direction to rotate the auger screw 25 in the reverse direction, and when the auger operation lever 32c is tilted backward, the auger motor 22 is operated in the forward direction to rotate the auger screw 25 in the forward direction. Furthermore, when the boom extension / bending operation lever 32b is tilted to the left When the boom extension / retraction lever 32b is tilted to the right, the arm 51 is bent upward relative to the tip of the boom 13. Also, when the gripping part vertical swivel operation lever 32d is tilted forward, the vertical swivel cylinder 62 is extended to swing the gripping part 81 downward (vertical swivel operation), and when the gripping part vertical swivel operation lever 32d is tilted backward, the vertical swivel cylinder 62 is retracted to swing the gripping part 81 upward (vertical swivel operation). Furthermore, when the gripping unit lateral swing operation lever 32e is tilted to the left, the lateral swing cylinder 71 is extended to swing the gripping unit 81 to the left (lateral swing operation), and when the gripping unit vertical swing operation lever 32e is tilted to the right, the lateral swing cylinder 71 is retracted to swing the gripping unit 81 to the right (lateral swing operation). Also, when the gripping unit rotation operation lever 32f is tilted forward, the gripper motor 79 is rotated forward to rotate the gripping unit 81 clockwise, and when the gripping unit rotation operation lever 32f is tilted backward, the gripper motor 79 is rotated backward to rotate the gripping unit 81 counterclockwise. Furthermore, when the gripping section opening / closing lever 32g is tilted forward, the gripper cylinder 99 is retracted to operate the gripping section 81 in the closing direction (the direction in which the object is gripped), and when the gripping section opening / closing lever 32g is tilted backward, the gripper cylinder 99 is extended to operate the gripping section 81 in the opening direction (the direction in which the object is released).

[0042] Furthermore, when the boom slewing and luffing operation lever 32a is operated while the mode selection switch 33 is selected for the gripping unit vertical operation mode, the operation control unit 102 combines the extension and retraction of the luffing cylinder 16, the extension and retraction of the telescopic cylinder 15, and the extension and retraction of the vertical swivel cylinder 62 to move the gripping unit 81 (the object gripped by the gripping unit 81) vertically in response to the operation of the boom slewing and luffing operation lever 32a. Specifically, when the boom slewing and luffing operation lever 32a is tilted forward, the operation combines the retraction of the luffing cylinder 16, the retraction of the telescopic cylinder 15, and the retraction of the vertical swivel cylinder 62 to move the gripping unit 81 vertically downward, and when the boom slewing and luffing operation lever 32a is tilted backward, the operation combines the extension of the luffing cylinder 16, the extension of the telescopic cylinder 15, and the extension of the vertical swivel cylinder 62 to move the gripping unit 81 vertically upward.

[0043] The moment calculation unit 103 calculates the moment Ma (see Figure 10) acting around the connecting pin (boom head pin) 52 based on the axial force F of the arm cylinder 55 detected by the arm cylinder axial force detector 125, the luffing angle θ1 of the boom 13 detected by the boom luffing angle detector 120, and the bending angle φ of the arm 51 detected by the arm bending angle detector 123. Here, the axial force F detected by the arm cylinder axial force detector 125 is a load acting from the gripping device 50 side with the connecting pin (boom head pin) 52 as the pivot point, and the product of this axial force F and the length of the arm acting on it (normal distance D, described later) is the moment Ma acting around the connecting pin (boom head pin) 52 from the gripping device 50 side. In other words, the moment Ma is calculated by converting the actual moment acting around the connecting pin 52 due to the weight of the gripping device 50 and the load applied to the gripping part 83 (the weight of the gripped utility pole P) into the axial force F applied to the arm cylinder 55.

[0044] Specifically, the moment calculation unit 103 calculates the angle (relative angle) between the axis of the boom 13 and the axis of the arm 51 based on the boom elevation angle θ1 detected by the boom elevation angle detector 120 and the arm bending angle φ detected by the arm bending angle detector 123, and calculates the normal distance D (see Figure 10) between the axis of the arm cylinder 55 and the pivot point (connecting pin 52) of the arm 51 according to this relative angle. This normal distance D is calculated based on a function that takes the relative angle between the axes of the boom 13 and the arm 51 as variables. Then, the moment calculation unit 103 derives the moment Ma using the formula "Ma = F × D" based on the axial force F of the arm cylinder 55 detected by the arm cylinder axial force detector 125 and the normal distance D calculated above.

[0045] The moment comparison unit 104 compares the moment Ma calculated by the moment calculation unit 103 with a preset regulated moment Mb, and outputs a regulated signal when moment Ma exceeds the regulated moment Mb.

[0046] When the regulating unit 105 receives a regulating signal from the moment comparison unit 104, it restricts the luffing operation of the boom 13 and the vertical swing operation of the gripping unit 81 in the direction that increases the moment Ma, regardless of the operation signal from the operating device 31. In other words, when the regulating unit 105 receives a regulating signal from the moment comparison unit 104, it restricts the luffing operation of the boom 13 and the vertical swing operation of the gripping unit 81 in the direction that increases the moment Ma until the moment Ma falls below the regulating moment Mb. In this embodiment, the vertical swing operation of the gripping unit 81 is the main operation that affects the increase or decrease of moment Ma (the movement of the center of gravity of the utility pole P in the front-rear direction), so both the vertical swing operation of the gripping unit 81 and the luffing operation of the boom 13 are subject to operation restriction. On the other hand, even when a restriction signal is input from the moment comparison unit 104, the regulating unit 105 allows the gripping unit 81 to swing vertically in the direction that decreases moment Ma (however, it does not allow the boom 13 to move up and down even in the direction that decreases moment Ma). This restriction on operation is performed by blocking the command signals output from the operation control unit 101 to the control valve 112 (a command signal to cause the gripping unit 81 to swing vertically in the direction that increases moment Ma, and a command signal to cause the boom 13 to move up and down).

[0047] Here, a specific example of restricting the vertical swing operation of the gripping part 81 will be described. Specifically, when the restricting unit 105 receives a restricting signal from the moment comparison unit 104, it allows vertical swing operation in the direction in which the tilt angle Ψ of the gripping part 81 decreases (the direction in which the moment Ma decreases) and restricts vertical swing operation in the direction in which the tilt angle Ψ of the gripping part 81 increases (the direction in which the moment Ma increases), based on the tilt angle Ψ of the gripping part 81 detected by the gripping part tilt angle detector 124. The direction in which the tilt angle Ψ of the gripping part 81 decreases (the direction in which the moment Ma decreases) is the direction in which the utility pole P gripped by the gripping part 81 approaches a vertical position, and the direction in which the tilt angle Ψ of the gripping part 81 increases (the direction in which the moment Ma increases) is the direction in which the utility pole P gripped by the gripping part 81 moves away from a vertical position. For example, as shown in Figure 11(A), when the upper part of the utility pole P gripped by the gripping part 81 is tilted forward, and the center of gravity of the utility pole P is located in front of the gripping part 81, if the moment Ma exceeds the regulating moment Mb, then the vertical swinging operation of the gripping part 81 in the upward direction (Y1 direction: the direction that brings the utility pole P closer to a vertical position) is permitted, but the vertical swinging operation of the gripping part 81 in the downward direction (Y2 direction: the direction that moves the utility pole P away from a vertical position) is restricted. On the other hand, as shown in Figure 11(B), when the upper part of the utility pole P gripped by the gripping part 81 is tilted to the rear and the center of gravity of the utility pole P is in front of the gripping part 81, if the moment Ma exceeds the regulating moment Mb, then the downward vertical swing operation of the gripping part 81 (Y2 direction: the direction that brings the utility pole P closer to a vertical position) is permitted, but the upward vertical swing operation of the gripping part 81 (Y1 direction: the direction that moves the utility pole P away from a vertical position) is restricted.

[0048] Next, the operation of the safety device during pole erection work in the gripping-type hole-digging pole-erecting vehicle 1 of this embodiment will be described. Unless otherwise specified in the following description, it will be assumed that the mode selection switch 33 is selected in normal mode.

[0049] When performing pole erection work with the gripping-type hole-digging pole-erecting vehicle 1, first, the operating device 31 is operated to appropriately move the boom 13, and the arm 51 is bent and extended, and the gripping part 81 is swung vertically, horizontally, and rotated, thereby moving the gripping part 81 close to the utility pole P (for example, a utility pole P placed horizontally at the work site) and aligning the gripping part 81 with the utility pole P. Next, the pair of gripping claws 82 are operated in the closing direction (closed operation) to grip the utility pole P with the gripping part 81. Then, the boom 13 and gripping device 50 are operated as appropriate to lift the utility pole P gripped by the gripping part 81 and move it above the pole-erecting hole (the pole-erecting hole excavated by the auger device 20). At this time, as shown in Figure 12, the gripping part 81 is gripping the utility pole P at a position away from the center of gravity, the upper part of the utility pole P is tilted forward, and the center of gravity of the utility pole P is shifted forward from the gripping position. From this state, the boom 13 and gripping device 50 are operated as appropriate to bring the utility pole P closer to a vertical position. Here, if the operator's erroneous operation causes the gripping unit 81 to swing vertically in the Y2 direction of Figure 12 (the direction that moves the utility pole P away from the vertical position), and the moment Ma acting around the connecting pin 52 increases and exceeds the regulated moment Mb, then the swinging operation and the luffing operation of the boom 13 are restricted (automatically stopped). This prevents the gripping device 50 from becoming overloaded and breaking. Note that if the moment Ma exceeds the regulated moment Mb, swinging the gripping unit 81 in the Y2 direction of Figure 12 (the direction in which moment Ma increases) is restricted, but swinging the gripping unit 81 in the Y1 direction of Figure 12 (the direction in which moment Ma decreases) is permitted. Therefore, the operator can operate the control device 31 again to swing the gripping unit 81 vertically in the Y1 direction of Figure 12, gradually decreasing the moment Ma around the connecting pin 52 and bringing the utility pole P closer to the vertical position. Then, by adjusting the tilt of the gripping part 81 in the front-to-back direction by vertically pivoting the gripping part 81, and by adjusting the tilt of the gripping part 81 in the left-to-right direction by rotating the gripping part 81, the utility pole P gripped by the gripping part 81 can be positioned vertically. If the position (front-to-back, left-to-right position) of the vertically positioned utility pole P and the pole installation hole are misaligned, the boom 13 can be extended and retracted and rotated to move the utility pole P horizontally (front-to-back, left-to-right direction) while maintaining the vertical position, thereby positioning the utility pole P directly above the pole installation hole.

[0050] Next, in order to move the vertically positioned utility pole P vertically downward toward the pole installation hole, the mode selection switch 33 is operated to switch from normal mode to gripping unit vertical operation mode. After switching the mode selection switch 33 to gripping unit vertical operation mode, the luffing and extending operation of the boom 13 and the vertical swing operation of the gripping unit 81 are linked in response to the operation of the boom slewing and luffing operation lever 32a, and the gripping unit 81 is moved vertically downward, thereby inserting the utility pole P, which is gripped by the gripping unit 81, into the pole installation hole. After inserting the utility pole P to the bottom of the pole installation hole, the lower end of the utility pole P can be embedded and compacted in the pole installation hole by filling the gap between the utility pole P and the pole installation hole with soil or other materials (by backfilling with excavated soil or crushed stones). This completes the pole installation work of setting the utility pole P in the pole installation hole.

[0051] As described above, according to the safety device of this embodiment, when the moment Ma around the pivot point of the arm 51 exceeds a preset regulating moment Mb, the vertical swinging operation of the gripping part 81 is restricted. This allows the vertical swinging operation of the gripping part 81 to be performed appropriately and safely, regardless of the gripping position of the utility pole P by the gripping part 81. Therefore, it is possible to prevent damage to structures such as the gripping device 50 and boom bracket 19 due to the generation of excessive moment Ma, thereby improving safety during work.

[0052] Furthermore, in the safety device according to this embodiment, when the moment Ma around the pivot point of the arm 51 exceeds a preset regulated moment Mb, the luffing operation of the boom 13 is also restricted along with the vertical swing operation of the gripping part 81. This reliably prevents damage to structures such as the gripping device 50 and boom bracket 19 due to the generation of an excessive moment Ma, thereby further improving work safety.

[0053] Furthermore, in the safety device according to this embodiment, if the moment Ma of the arm 51 around the pivot point exceeds the regulating moment Mb, the luffing cylinder 16 and the vertical swivel cylinder 62 will not operate even if the arm is accidentally operated in an unsafe direction (a direction in which moment Ma increases), thus ensuring safety. Since the vertical swivel cylinder 62 operates only when operated in the direction that decreases moment Ma, even if moment Ma reaches the limiting moment Mb and the operation restriction is activated, the operator can safely operate the gripping part 81 vertically without getting stuck (making it easier to operate quickly when the operation restriction is activated), thus achieving both safety and workability.

[0054] It should be noted that the present invention is not limited to the embodiments described above, and can be appropriately improved without departing from the spirit of the invention.

[0055] In the above embodiment, the axial force F of the arm cylinder 55 was detected by a pin-type load cell (arm cylinder axial force detector 125) provided on the connecting pin 56. However, the configuration is not limited to this, and for example, the pressure of the hydraulic fluid supplied to the bottom-side oil chamber and the rod-side oil chamber of the arm cylinder 55 may be detected, and the axial force F of the arm cylinder 55 may be detected from the relationship between these pressure differences and the pressure-receiving areas of both oil chambers.

[0056] In the above embodiment, the vertical swivel operation of the gripping part 81 was restricted when the moment Ma exceeded the regulating moment Mb. However, the configuration is not limited to this, and other operations of the gripping device 50, such as the bending and extending operation of the arm 51 and the rotational operation of the gripping part 81, may also be subject to operation restriction. Furthermore, if the moment Ma exceeds the regulating moment Mb, in addition to this operation restriction, an alarm may be activated, for example, by sounding an alarm, using an alarm lamp or displaying an alarm, to alert the worker.

[0057] In the above embodiment, the operating device 31 is provided in the operating seat 30 on the vehicle body 2, but the 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).

[0058] Furthermore, while the above embodiment illustrates a PTO-driven hole-digging and pole-erecting vehicle that uses a PTO (power take-off) mechanism to extract engine power and drive a hydraulic pump, the configuration is not limited to this. An electric-driven (battery-driven) hole-digging and pole-erecting vehicle or a hybrid vehicle equipped with both, which selectively switches the power source, may also be used. [Explanation of Symbols]

[0059] 1 Grasping type hole digging pole erecting vehicle 2 car bodies 13 Boom 16. Luffing Cylinder (Boom Luffing Cylinder) 19 Boom Bracket 31 Operating device 50 Gripping device 51 Arm 52 Connecting pin (pivot point) 55 Arm Cylinder (Arm Actuator) 62. Vertical Swivel Cylinder (Gripping Actuator) 80 Grippa 81 Gripping part 100 controllers 101 Position calculation section 102 Operation Control Unit 103 Moment Calculation Unit (Moment Detection Unit) 104 Moment Comparison Section 105 Regulatory Department 124 Gripping section tilt angle detector (tilt angle detection unit) 125 Arm cylinder axial force detector (moment detection unit)

Claims

1. a boom provided on the vehicle body so as to be able to be raised and lowered; an arm provided at the tip of the boom so as to be swingable along the boom hoisting surface; a gripping portion provided at a tip end of the arm so as to be swingable along the undulating surface and capable of gripping an object; a boom hoisting actuator that raises and lowers the boom; an arm actuator that swings the arm relative to the tip of the boom along the undulating surface; a gripping portion actuator that swings the gripping portion along the undulating surface relative to the tip of the arm; a moment detection unit that detects a moment acting around a swing fulcrum of the arm when the gripping unit grips an object; A safety device for a gripping-type hole-digging pole-setting vehicle, characterized in that it is equipped with a regulating unit that regulates the operation of the gripping unit actuator when the moment detected by the moment detection unit exceeds a predetermined regulating moment.

2. 2. A safety device for a gripping-type pole digging vehicle as described in claim 1, characterized in that the regulating unit also regulates the operation of the boom raising and lowering actuator when the moment detected by the moment detecting unit exceeds the regulated moment.

3. a tilt angle detection unit that detects a tilt angle of the gripping portion relative to a horizontal plane, A safety device for a gripping-type pole digging vehicle as described in claim 1 or 2, characterized in that when the moment detected by the moment detection unit exceeds the regulating moment, the regulating unit allows the operation of the gripping unit actuator to swing the gripping unit in a direction that reduces the tilt angle based on the detection information of the tilt angle detection unit, and restricts the operation of the gripping unit actuator to swing the gripping unit in a direction that increases the tilt angle.

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