JP5362255B2 - Aerial work platform - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle for high lift work can adjust a workbench so as to be parallel with an absolute horizontal surface even in the case of positioning it in an inclined surface, restricting costs. <P>SOLUTION: This vehicle for high lift work 1 includes: a workbench 8 provided in a chip of a boom 5 freely to swing; a workbench inclination detector 21 for detecting an angle of inclination of the workbench 8 relative to a vehicle body 2; a hoist angle detector 23; a leveling cylinder 61 for swinging the workbench 8 in the vertical direction; a leveling device 60 for holding the workbench 8 at a reference leveling angle; a leveling adjusting valve for changing the reference leveling angle; and a control unit 30 for setting a predetermined angle range, in which a change of the reference leveling angle is allowable. A vehicle body angle detector 22 is provided to detect angle of inclination of the vehicle body 2 relative to the absolute horizontal surface. The control unit 30 corrects the predetermined angle range corresponding to the angle of inclination of the vehicle body 2 detected by the vehicle body angle detector 22. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an aerial work vehicle including a leveling device that holds a work table provided at a tip end portion of a boom that can freely move up and down, in a horizontal posture regardless of an up and down angle of the boom.

  As an example of the aerial work vehicle, the vehicle includes a boom on which a swiveling motion, a undulation motion, and a telescopic motion can be freely arranged on a travelable vehicle body, and a work table on which a worker rides at the tip of the boom. In some cases, an operator who has boarded a work table moves the work table to a desired work position at a desired height to perform work. For example, the work table is used for power distribution work and construction work. In such an aerial work vehicle, the floor of the work table is always applied regardless of the boom up / down angle so that the work table on which the operator is boarding does not tilt as the boom moves up and down. A leveling device is provided to keep it parallel to the vehicle body. Conventionally, various devices have been proposed as a leveling (equilibrium) device for a work table provided at the tip of such a boom. For example, a so-called relative circuit composed of a closed hydraulic circuit that communicates a lower leveling cylinder that expands and contracts in response to the boom swinging movement and an upper leveling cylinder that is provided at the tip of the boom and supports the work table in parallel with the vehicle body. There is a square leveling device (see, for example, Patent Document 1).

  In addition, a so-called absolute configuration that is configured to control the expansion / contraction operation of the (upper) leveling cylinder by using a worktable angle detector that can detect the inclination between the worktable and the vehicle body without using the lower leveling cylinder. There is also a square leveling device. For example, in an absolute angle type leveling device, the leveling reference angle when the leveling control is performed by tilting the workbench is changed due to oil leaks from the hydraulic circuit connected to the leveling cylinder or changes over time. It may be difficult to control in parallel with the. In order to prepare for such a case, for example, a switch is provided on the work table to adjust the tilt of the work table, and the leveling cylinder can be expanded and contracted by the operator turning on the switch to adjust the tilt of the work table. It has become.

In this way, the tilt adjustment of the workbench is performed based on the operator's switch operation. When the workbench is parallel to the vehicle body, the switch operation is stopped and the supply of hydraulic oil to the leveling cylinder is cut off. It is designed to be held in a state. At the time of this adjustment, for example, if the operator mistakenly operates the switch and continues to turn on the switch, the work table may be excessively inclined and the worker may fall from the work table. In order to prevent such a situation, for example, when a switch operation is performed, the work table is allowed to swing within a predetermined angle range, but on the other hand, it does not swing beyond the predetermined angle range. It is configured to be regulated. In addition, an aerial work vehicle equipped with a traveling body capable of traveling is inherently equipped with a vehicle body angle detector that detects the inclination angle of the vehicle body with respect to the absolute horizontal plane in order to determine the stability of the vehicle body. Based on the inclination angle of the vehicle body, for example, it is configured to prevent a fall due to a fall moment.
JP 2002-156039 A

  When an aerial work vehicle such as that described above is positioned on an inclined surface that is inclined with respect to the absolute horizontal plane, for example, the work table is parallel to the vehicle body by the leveling device, that is, is inclined by the inclination angle of the inclined surface with respect to the absolute horizontal plane. Retained. At this time, since the floor surface of the work table is inclined with respect to the absolute horizontal plane, there is a possibility that the workability of an operator who has boarded the work table may deteriorate. Therefore, for example, by turning on the switch, it is possible to adjust the inclination of the work table so that the work table is parallel to the absolute horizontal plane. However, when the inclination angle of the inclined surface exceeds the predetermined angle range, the swinging of the work table is restricted before the work table is parallel to the absolute horizontal surface when adjusting the inclination of the work table. Therefore, there has been a problem that it is difficult to adjust the work table so that it is parallel to the absolute horizontal plane.

  Moreover, the method of using the ground angle detector which can detect the inclination-angle of a work table with respect to an absolute horizontal surface instead of a work table angle detector with respect to the said subject can be considered. However, in this case, regardless of the inclination angle of the vehicle body, the inclination can be adjusted so that the work table is parallel to the absolute horizontal plane, while the vehicle body angle detector that is essentially required for the construction of an aerial work vehicle. Thus, the tilt angle of the vehicle body with respect to the absolute horizontal plane is also detected. For this reason, the configuration of the apparatus becomes complicated, and such a ground angle detector is generally an expensive apparatus, and thus there is a problem that it leads to an increase in the cost of an aerial work vehicle.

  The present invention has been made in view of such a problem, and it is possible to adjust the work table to be parallel to the absolute horizontal plane even when the aerial work vehicle is located on an inclined surface while suppressing an increase in cost. The purpose is to provide a high-altitude work vehicle.

In order to achieve the above object, an aerial work vehicle according to the present invention includes a traveling body configured to travel with a vehicle body, a boom provided on the vehicle body so as to be able to undulate at least, and a tip of the boom. A work table provided so as to be swingable up and down along the undulating surface of the boom, and a work table angle detecting means for detecting an inclination angle of the work table with respect to the vehicle body within the surface along the undulating surface (for example, Working table tilt detector 21 and hoisting angle detector 23) in the embodiment, a leveling actuator that swings the working table up and down with respect to the boom (for example, the leveling cylinder 61 in the embodiment), and hoisting of the boom depending on the operating actuates the leveling actuator, with respect to the vehicle body detected by the worktable angle detecting means regardless of the undulations of the boom And leveling means for holding substantially horizontal the angle of inclination of the serial worktable (e.g., a leveling device 60 in the embodiment), by operating the leveling actuator, the leveling is oscillating the worktable up and down relative to the boom Based on an operation to the tilt angle changing means (for example, the control unit 30 and the leveling adjustment valve 75 in the embodiment) for changing the tilt angle of the work table held by the means, and the tilt angle changing means . in the that put to change the inclination angle of the worktable held by the leveling means, the angular range setting means changes the worktable inclination angle is set a predetermined angle range allowed (e.g., embodiments Te Control unit 30). Then, further the vehicle body angle detecting means for detecting an inclination angle of the vehicle body with respect to the absolute horizontal plane (e.g., the vehicle body angle detector 22 in the embodiment) wherein the angular range setting means, said Ru is detected by the vehicle body angle detecting means according to the inclination angle of the vehicle body, the predetermined angular range is configured to set the predetermined angle range such that the angular range including a surface approximately parallel to the absolute horizontal plane.

Moreover, in the aerial work vehicle according to the present invention, it is preferable that the angle range setting means sets the predetermined angle range so as to be a fixed angle range in the vertical direction of the absolute horizontal plane.

  The aerial work vehicle according to the present invention changes the leveling reference angle according to the inclination angle of the vehicle body with respect to the absolute horizontal plane detected by the vehicle body angle detection means that is essentially required for the construction of the aerial work vehicle (work The predetermined angle range in which the swing of the table is allowed is corrected by the angle range setting means. Here, the change of the leveling reference angle exceeding the predetermined angle range (swing of the work table) is regulated by some kind of regulating means. From this configuration, the angle range setting means can correct the predetermined angle range so as to be set near the absolute horizontal plane, for example. By correcting in this way, even when the inclination angle of the inclined surface on which the work vehicle is located exceeds the predetermined angle range, the leveling reference angle is set without restricting the swing of the work table. It can be changed to near the absolute horizontal plane. That is, even when an aerial work vehicle is positioned on an inclined surface, the work table can be adjusted to be parallel to the absolute horizontal plane. Moreover, it is the structure which correct | amends a predetermined angle range using the detection result of the vehicle body angle detector originally attached with respect to the aerial work vehicle provided with the traveling body which can drive | work. Therefore, since it is not necessary to add a new device, the device configuration is not complicated and the cost can be suppressed.

  In the above-described aerial work vehicle according to the present invention, it is preferable that the angle range setting means corrects the predetermined angle range so as to be a constant angle range in the vertical direction including the absolute horizontal plane. When corrected in this way, it becomes possible to adjust the work table to be parallel to the absolute horizontal plane regardless of the inclination angle of the ground on which the work platform is located with respect to the absolute horizontal plane. Therefore, by adjusting the floor surface of the work table in parallel to the absolute horizontal plane, it is possible to improve the work efficiency of the worker who has boarded the work table.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As an example of an aerial work device to which the present invention is applied, a side view of a self-propelled aerial work vehicle (hereinafter referred to as an aerial work vehicle) is shown in FIG. First, the overall configuration of the aerial work vehicle 1 will be described with reference to FIG.

  The aerial work vehicle 1 has tire wheels 3 a and 3 b on the front, rear, left and right of a vehicle body (also referred to as a traveling body) 2, and a traveling motor 51 is connected to each tire wheel. Of the four wheels, two tire wheels 3b are steered wheels, and are steered based on a steering operation. For this reason, the traveling motor 51 is driven to rotate in forward and reverse directions and the steered wheels are steered to be able to travel in a desired direction. A two-wheel drive configuration in which two of the four wheels are driving wheels may be used.

  On the upper part of the vehicle body 2, a turntable 4 is arranged so as to be able to turn horizontally with respect to the vehicle body 2 by operation of a turning motor 52 provided therein. A boom 5 is pivotally connected to an upper end portion of the swivel base 4 so as to freely swing up and down. The boom 5 is attached to the swivel base 4 by an expansion and contraction operation of a hoisting cylinder 53 straddled between the swivel base 4 and the boom 5. On the other hand, it can move up and down. The boom 5 includes a base end boom 5a that is pivotally connected to the swivel 4 and an intermediate boom 5b and a front end boom 5c that are telescoped into the base end boom 5a. In addition, the boom 5 is configured to be extendable and retractable by the operation of an extendable cylinder 54 provided in the proximal boom 5a, and a bracket 6 is attached to the distal end portion.

  The bracket 6 is pivotally connected to the tip of the boom 5 at a pivotal portion 6 a and can swing up and down along the undulating surface of the boom 5. Further, as will be described later, the bracket 6 is always held at a constant angular posture with respect to the vehicle body 2 by the leveling device 60 shown in FIG. A work table 8 is attached to the upper surface of the bracket 6 via a swivel device 7, and the work table 8 can be swiveled horizontally with respect to the bracket 6 by operation of a swing motor 55 provided on the swivel device 7. It has become.

  An operation device 10 for performing a traveling operation of the aerial work vehicle 1 and a moving operation of the work table 8 is disposed on the work table 8. The operating device 10 is roughly composed of a traveling operating device 11 that performs a traveling operation and a boom operating device 12 that performs a moving operation of the work table 8 with respect to the vehicle body 2. The operation device 10 includes, for example, an operation lever for performing operations such as a traveling operation of the aerial work vehicle 1, a turning operation of the swivel base 4, a hoisting and extending operation of the boom 5, and a swinging operation of the work base 8. A switch or the like is provided. Note that the boom operating device 12 is used when an abnormality occurs in an operator who has boarded the work table during work at a high place after the work table 8 is moved to a high place, or when the boom is provided on the work table 8. It is also provided on the vehicle body 2 side in preparation for a case where the operating device breaks down, and is composed of an upper boom operating device 12a provided on the work table 8 and a lower boom device 12b provided on the swivel 4. .

  The hydraulic unit 40 is provided inside the swivel 4 and is configured to supply hydraulic oil to hydraulic actuators provided in each part. FIG. 4 shows a schematic block diagram of hydraulic control. As shown in FIG. 4, the hydraulic unit 40 is provided with a hydraulic pump P that sucks the hydraulic oil stored in the tank T and generates a predetermined volume of hydraulic pressure. As a drive source for driving the hydraulic pump P, either an engine or a battery-driven motor may be used. The hydraulic unit 40 includes a hydraulic motor P, a swing motor 52, a hoisting cylinder 53, a telescopic cylinder 54, a swing motor 55, and other hydraulic actuators. Solenoid valves SV1 to SV5... For controlling the supply of hydraulic oil are disposed in the connecting oil passages. As the electromagnetic valves SV1 to SV5 for controlling the movement of the work table 8, electromagnetic proportional valves whose direction and flow rate are set in accordance with an input command signal are used. In FIG. 4, electrical or optical signal lines are indicated by dotted lines, and hydraulic oil connection lines are indicated by solid lines.

  The control unit 30 is provided in the swivel 4 like the hydraulic unit 40 described above. Specifically, the control unit 30 includes a CPU 31 that performs arithmetic processing, a memory 32 that stores a control program, and the like, and controls the operation of each part of the aerial work vehicle 1 based on a control program that is set and stored in advance. The control unit 30 and the operating device 10 are connected by a signal cable that extends through the boom 5. When an operation signal is input from the operating device 10, the control unit 30 configured as described above outputs a command signal corresponding to the operation signal to the corresponding electromagnetic valves SV <b> 1 to SV <b> 5 inside the hydraulic unit 40, The operation of the actuator 50 (51 to 55) is controlled. For this reason, the operator who has boarded the work table 8 operates the operation device 10 to travel the aerial work vehicle 1, to turn the swivel table 4, to raise and lower the boom 5, to extend and retract, and to swing the work table 8. Thus, the work table 8 can be moved to a desired high place work position to perform work.

  FIG. 3 shows the configuration of the leveling device 60 including the angle adjustment control circuit for changing the inclination angle of the work table 8 in the aerial work vehicle 1 configured as described above. The leveling device 60 will be described with reference to FIG.

  The leveling device 60 mainly includes a work table tilt detector 21, a vehicle body angle detector 22, a undulation angle detector 23, a leveling cylinder 61, a leveling adjustment valve 75, and a check valve 76, and is a so-called absolute angle type leveling. Device. As shown in FIG. 3, the workbench inclination detector 21 is installed, for example, in the vicinity of the pivotal portion 6 a of the bracket 6, and detects the swing angle of the workbench 8 with respect to the boom 5. The undulation angle detector 23 is installed, for example, under the base end boom 5a, and detects the undulation angle of the boom 5 with respect to the vehicle body 2. Then, the control unit 30 receives the swing angle of the work table 8 detected by the work table tilt detector 21 and the hoisting angle of the boom 5 detected by the hoisting angle detector 23, and outputs the detection results. Based on this, the relative angle of the work table 8 with respect to the vehicle body 2 is calculated.

  The vehicle body angle detector 22 is attached to the vehicle body 2, for example, and detects the inclination angle of the vehicle body 2 with respect to the absolute horizontal plane and outputs it to the control unit 30. As the vehicle body angle detector 22, for example, a linear inclination sensor that can detect the inclination angle of the vehicle body 2 with respect to the absolute horizontal plane by detecting the liquid level of the liquid sealed inside can be used. In the leveling cylinder 61, an oil passage 62 is connected to the tube-side oil chamber 61t, and an oil passage 63 is connected to the rod-side oil chamber 61r, so that the leveling cylinder 61 can be expanded and contracted. The leveling cylinder 61 has one end pivoted to the tip end of the tip boom 5 c and the other end pivoted to the lower end of the bracket 6. Therefore, when the leveling cylinder 61 is expanded and contracted, the bracket 6 can swing up and down on the undulating surface of the boom 5 with the pivoting portion 6a as the center.

  The leveling adjustment valve 75 is a 4-port 3-position electromagnetic proportional valve. A hydraulic pump P is connected to a pump port (supply port) 75p of the solenoid valve via an oil passage 71, and a tank port (drain port) 75t It is connected to the tank T through the oil passage 72. An oil passage 62 is connected to the cylinder A port 75a, and an oil passage 63 is connected to the cylinder B port 75b. At the neutral position of the leveling adjustment valve 75, the pump port 75p is shut off as shown in the figure, and the cylinder A port 75a and the cylinder B port 75b are connected to the tank port 75t. For this reason, the hydraulic oil is not supplied from the hydraulic pump P to any of the oil passages 62 and 63, and the leveling state in which the angle posture of the work table 8 is maintained by the action of the check valve 76 regardless of the undulation angle of the boom 5. Retained. Further, the leveling adjustment valve 75 is electrically connected to the control unit 30 through a signal line.

  The boom operating device 12 (12 a, 12 b) is provided with a leveling switch 13 for changing the tilt angle of the work table 8, and its signal line is connected to the control unit 30. The control unit 30 controls the operation of the leveling adjustment valve 75 based on the operation signal input from the leveling switch 13. The leveling switch 13 includes an upper leveling switch 13a provided on the upper boom operating device 12a and a lower leveling switch 13b provided on the lower boom operating device 12b.

  The overall configuration of the aerial work vehicle 1 has been described so far, but the operation of the leveling device 60 will be described below. In the following description, the counterclockwise direction of FIGS. 1 and 2 is defined as the positive swing direction and the clockwise direction is defined as the negative swing direction with respect to the swing direction of the work table 8 (bracket 6). Do.

  As described above, the aerial work vehicle 1 is configured to be movable back and forth and to the left and right, and the boom 5 can be expanded and contracted, raised and lowered with respect to the swivel 4 disposed on the upper portion of the vehicle body 2. ing. An operator rides on the work platform 8 provided at the tip of the boom 5 and moves the work platform 1 so that the work platform 8 is positioned at a desired work location, as well as raising and lowering the boom 5. I do.

  First, with reference to FIG. 1, a description will be given of a case where the aerial work vehicle 1 is moved and positioned, for example, on the ground parallel to the absolute horizontal plane. At this time, the vehicle body angle detector 22 detects that the vehicle body 2 is parallel to the absolute horizontal plane (zero inclination angle), and outputs this detection result to the control unit 30. At this time, the results detected by the work table inclination detector 21 and the undulation angle detector 23 are also input to the control unit 30, and the control unit 30 calculates the relative angle of the work table 8 with respect to the vehicle body 2. The control unit 30 stores the inclination angle of the vehicle body 2 with respect to the input absolute horizontal plane and the calculated relative angle of the work table 8 with respect to the vehicle body 2 in the memory 32, and the work table 8 is parallel to the vehicle body 2. Command signal is output to the leveling adjustment valve 75. By doing so, the leveling cylinder 61 is expanded and contracted, and the bracket 6 swings in the positive or negative direction around the pivoting portion 6a, so that the work table 8 ( The floor surface of the workbench 8 is parallel and held in a leveled state.

  By the way, the work table 8 may be inclined with respect to the vehicle body 2 (in this case, an absolute horizontal plane) in the leveling state due to, for example, an oil leak from a hydraulic circuit constituting the leveling device 60 or a change over time. In this case, since the work table 8 is tilted, the workability of an operator who has boarded the work table 8 may be reduced. Therefore, the tilt is adjusted so that the work table 8 is parallel to the vehicle body 2. Here, when adjusting the inclination of the work table 8, the operator turns on the leveling switch 13 (13a, 13b). By doing so, the operation signal is input from the leveling switch 13 to the control unit 30.

  For example, in FIG. 1, when the rear end side of the work table 8 (the side on which the operating device 10 is disposed) is raised with respect to the absolute horizontal plane, the leveling cylinder 61 is extended based on the operation signal of the leveling switch 13. Thus, the bracket 6 is swung in the positive direction. Specifically, the control unit 30 determines the leveling adjustment valve 75 of the hydraulic unit 40 so that the work table 8 is parallel to the vehicle body 2 based on the calculated relative angle of the work table 8 to the vehicle body 2. By outputting a command signal, the valve spool of the leveling adjustment valve 75 shown in FIG. 3 is moved to the right. In this position, the oil passage 71 and the oil passage 62, the oil passage 72 and the oil passage 63 are connected to each other, and the hydraulic oil discharged from the hydraulic pump P passes through the oil passage 62 and the tube side oil chamber 61t of the leveling cylinder 61. And the leveling cylinder 61 is extended. The hydraulic oil discharged from the rod side oil chamber 61r of the leveling cylinder 61 returns to the tank T through the oil passage 63 and the oil passage 72.

  By this operation, the bracket 6 can be adjusted in such a manner that the bracket 6 swings in the positive direction around the pivoting portion 6 a and the work table 8 is parallel to the vehicle body 2. Basically, when the floor surface of the work table 8 is parallel to the absolute horizontal surface and the operator stops the switch operation of the leveling switch 13, the control unit 30 turns off the command signal to the leveling adjustment valve 75. . As a result, the valve spool of the leveling adjustment valve 75 returns to the neutral position shown in FIG. 3, the hydraulic oil supply from the hydraulic pump P to the leveling cylinder 61 is cut off, and the check valve 76 cuts off the oil passage 62 and the oil passage 63. To maintain the leveling state.

  Here, when the leveling switch 13 is turned on and the operation signal is continuously input, the control unit 30 presets and stores the swing angle of the work table 8 based on the operation signal in the memory 32. When the predetermined angle range is to be exceeded, the command signal to the leveling adjustment valve 75 is forcibly turned off to restrict the operation of the leveling cylinder 61 based on the operation signal. The “predetermined angle range” set and stored in advance in the memory 32 is adjusted by the operator on the work table 8 by operating the upper leveling switch 13a based on the input inclination angle of the vehicle body 2 with respect to the absolute horizontal plane. The angle range in which the work table 8 is not excessively inclined by the operation of the leveling cylinder 61 is defined with reference to the angle range of normal leveling adjustment (horizontal adjustment). Specifically, when the absolute horizontal plane is calculated based on the detected inclination angle of the vehicle body 2 and the allowable inclination angle of the work table 8 is set to 12 degrees centered on the calculated absolute horizontal plane, for example, the operation signal Is set so that the swing angle of the workbench 8 that changes due to the operation of the leveling cylinder 61 is about 10 degrees.

  Referring to FIG. 1, the vehicle body angle detector 22 detects the inclination angle of the vehicle body 2 with respect to the absolute horizontal plane (zero degrees in the case of FIG. 1), and the absolute horizontal plane 90 is calculated by using this detected value. Then, the control unit 30 swings the work table 8 in the positive and negative directions around the calculated absolute horizontal plane 90, for example, exceeding an angle range of 5 degrees (the allowable angle X is 5 degrees in FIG. 1), respectively. The operation of the leveling cylinder 61 based on such an operation signal is restricted. Here, the angle at which the workbench 8 swings as a result of the command signal corresponding to the operation signal being output is detected by the workbench inclination detector 21. Therefore, even when an operator who has boarded the work table 8 erroneously continues to turn on the upper leveling switch 13a, the operation of the leveling cylinder 61 is restricted before the work table 8 is excessively inclined. Therefore, the worker who has boarded the work table 8 does not fall down, and safety when adjusting the inclination of the work table 8 can be ensured.

  Next, as shown in FIG. 2, the operation of the leveling device 60 when the aerial work vehicle 1 is moved and positioned, for example, on an inclined surface (a surface inclined by an inclination angle β degrees with respect to the absolute horizontal plane) will be described. To do. Here, the magnitude relationship between the inclination angle β and the allowable angle X illustrates the case where the inclination angle β> the allowable angle X.

  At this time, as in the case where the above-described aerial work vehicle 1 is located on the ground parallel to the absolute horizontal plane, the control unit 30 is controlled by the vehicle body angle detector 22, the workbench inclination detector 21, and the undulation angle detector 23. The detection result is input and stored in the memory 32, and a command signal that causes the work table 8 to be parallel to the vehicle body 2 is output to the leveling adjustment valve 75. By doing so, the leveling cylinder 61 is extended or reduced, and the work table 8 is parallel to the vehicle body 2 and held in the leveling state regardless of the raising / lowering angle of the boom 5.

  In the leveling state, the work table 8 is parallel to the holding inclination position 91 inclined by an inclination angle β degrees with respect to the absolute horizontal plane, and the workability of an operator who has boarded the work table 8 may be reduced. Then, the operator turns on the leveling switch 13 to adjust the work table 8 to be parallel to the absolute horizontal plane. In FIG. 2, each inclination angle of the work table 8 is represented with the holding inclination position 91 as a reference.

  Here, it is assumed that the predetermined angle range described above is set without being based on the inclination angle of the vehicle body 2 with respect to the absolute horizontal plane detected by the vehicle body angle detector 22. In this case, the control unit 30 exceeds the angular range of, for example, 5 degrees (the allowable angle X is 5 degrees in FIG. 2) in the positive and negative directions around the holding tilt position 91 in the leveling state. The operation of the leveling cylinder 61 based on the operation signal that swings is restricted. At this time, as shown in FIG. 2, even if the tilt of the work table 8 is adjusted so that it is parallel to the absolute horizontal plane 90 from the holding tilt position 91, the tilt angle β> the allowable angle X The operation of the leveling cylinder 61 that is swung further in the positive direction by the control unit 30 at the inclined position swung by the allowable angle X degrees is restricted. Therefore, when the predetermined angle range is set without being based on the inclination angle of the vehicle body 2 relative to the absolute horizontal plane detected by the vehicle body angle detector 22, the work table 8 is parallel to the absolute horizontal plane 90. It is difficult to adjust.

  Therefore, like the control unit 30 of the aerial work vehicle 1 to which the present invention is applied, the predetermined angle range is corrected and set based on the inclination angle of the vehicle body 2 with respect to the absolute horizontal plane detected by the vehicle body angle detector 22. Thus, the tilt can be adjusted so that the work table 8 is parallel to the absolute horizontal plane 90 without restricting the operation of the leveling cylinder 61. Specifically, referring to FIG. 2, the control unit 30 is inclined by the inclination angle β in the positive direction from the holding inclination position 91 based on the inclination angle β of the vehicle body 2 with respect to the absolute horizontal plane stored in the memory 32. The absolute horizontal plane 90 is calculated. Then, the operation of the leveling cylinder 61 based on an operation signal that swings in the positive and negative directions around the calculated absolute horizontal plane 90, for example, exceeding an angle range of 5 degrees, for example, is restricted.

  When the operation of the leveling cylinder 61 is restricted in this way, when the operator turns on the leveling switch 13 and adjusts the tilt of the work table 8 located at the holding tilt position 91, the leveling cylinder 61 is based on the operation signal. Is extended, and the work table 8 is swung in the positive direction. Then, when the operator stops the switch operation by swinging by β degrees in the positive direction from the holding inclination position 91, the floor surface of the work table 8 is parallel to the absolute horizontal surface 90, the work table 8 is tilted. Adjustment is complete. If the operator mistakenly continues the switch operation, the operation of the leveling cylinder 61 is restricted by the control unit 30 at the inclined position that is swung in the positive direction by (β + X) degrees from the holding inclined position 91. Therefore, the work table 8 does not tilt excessively. Therefore, the operator 8 who adjusts the work table 8 in parallel with the absolute horizontal plane 90 and gets on the work table 8 while restricting the work table 8 from being excessively inclined at the time of tilt adjustment and ensuring safety. Work efficiency can be improved.

  Further, in the self-propelled aerial work vehicle 1 as shown in FIG. 2, a vehicle body angle detector 22 for detecting the inclination angle of the vehicle body 2 with respect to the conventional absolute horizontal plane is inherently attached. The stability of the vehicle body 2 (the aerial work vehicle 1) is determined based on the inclination angle of the vehicle body 2 detected by the vehicle body angle detector 22. If the stability is expected to be impaired, for example, the moving operation of the aerial work vehicle 1 and the hoisting operation of the boom 5 are restricted. In this way, the detection result obtained by the vehicle body angle detector 22 that is originally attached is used, and it is not necessary to add a new device. Therefore, it is possible to adjust the inclination of the work table 8 so as to be parallel.

  Furthermore, as shown in FIG. 2, when the work platform 1 is located on an inclined surface, the work table 8 is brought to an absolute horizontal plane 90 due to, for example, oil leakage from a hydraulic circuit constituting the leveling device 60 or a change with time. On the other hand, it may be in a state of being inclined in the positive direction to be larger than the allowable angle X. Even in such a case, by correcting and setting the predetermined angle range based on the inclination angle of the vehicle body 2 in the same manner as described above, the operation of the leveling cylinder 61 is not restricted during the adjustment of the inclination with respect to the absolute horizontal plane 90. Thus, the work table 8 can be adjusted to be parallel. If the operator mistakenly continues the switch operation, at a position that is swung by an allowable angle X degrees in the negative direction from the absolute horizontal plane 90, that is, at an inclined position of (β-X) degrees shown in FIG. Since the operation of the leveling cylinder 61 is regulated by the control unit 30, the work table 8 does not tilt excessively.

  In the above-described embodiment, regardless of the inclination angle of the inclined surface on which the aerial work vehicle 1 is located, the allowable angle X (for example, 5 degrees) is set in the positive and negative directions around the reference inclination position at the time of inclination adjustment. Although the structure which controls the action | operation of the leveling cylinder 61 exceeding was illustrated, it is not limited to this structure. For example, it is good also as a structure which controls the magnitude | size of the permissible angle X according to the magnitude | size of the inclination angle of the inclined surface in which the high work vehicle 1 was located.

  Moreover, although the case where the electromagnetic proportional valve which controls the supply direction and valve opening degree of hydraulic oil according to a command signal was used as the leveling adjustment valve 75 in the above-described embodiment, the hydraulic oil was controlled according to the command signal. An electromagnetic valve for switching the supply direction and a throttle (fixed throttle or variable throttle) for controlling the supply amount may be provided.

It is a side view of an aerial work vehicle (a state where the vehicle body is horizontal) to which the present invention is applied. It is a side view of an aerial work vehicle to which the present invention is applied (a state in which the vehicle body is inclined). It is a block diagram which shows the structure of the leveling apparatus containing the control circuit for workbench angle adjustment. It is a block diagram which shows the outline | summary structure of the hydraulic control in the said aerial work vehicle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aerial work vehicle 2 Car body 5 Boom 8 Work table 21 Work table inclination detector (work table angle detection means)
22 Body angle detector (body angle detection means)
23 Undulating angle detector (workbench angle detecting means)
30 Control unit (reference angle changing means, angle range setting means)
60 Leveling device (leveling means)
61 Leveling cylinder (leveling actuator)
75 Leveling adjustment valve (reference angle changing means)

Claims (2)

A traveling body configured to travel with a vehicle body;
A boom that is provided at least freely up and down in the vehicle body;
A workbench provided at the tip of the boom so as to swing up and down along the undulating surface of the boom;
A work table angle detection means for detecting an inclination angle of the work table with respect to the vehicle body in a plane along the undulation surface;
A leveling actuator that swings the work table up and down with respect to the boom;
Leveling means for actuating the leveling actuator in response to the raising and lowering operation of the boom, and maintaining the inclination angle of the worktable with respect to the vehicle body detected by the worktable angle detecting means regardless of the boom raising and lowering substantially horizontally. ,
Inclination angle changing means for operating the leveling actuator to swing the work table up and down with respect to the boom and changing the inclination angle of the work table held by the leveling means ;
Said that put to change the inclination angle of the worktable held by the leveling means, for setting a predetermined angular range which changes are allowed in the worktable of the inclination angle on the basis of the operation to the tilt angle changing means In an aerial work platform having an angle range setting means,
A vehicle body angle detecting means for detecting an inclination angle of the vehicle body with respect to an absolute horizontal plane;
It said angular range setting means in response to said inclination angle of the vehicle body that will be detected by the vehicle body angle detecting means, the predetermined angle range such that the predetermined angle range is an angle range including a surface approximately parallel to the absolute horizontal plane An aerial work vehicle characterized by setting . Said angular range setting means, Aerial according to claim 1, characterized in that setting the predetermined angular range so that each constant angle range in the vertical direction of the absolute horizontal plane.

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