JP2005138946A - Work vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a work vehicle capable of increasing safety in jacking operation. <P>SOLUTION: In this work vehicle, a controller 80 controls the operation of a parking assisting device 50 to brake both front wheels and rear wheels when the lower end parts of all jacks are detected to be in a non-contact state by jack ground-contact detectors 82a, 82c, and 82d, on operation signals are inputted from a power take-off switch 14 thereto, and operation signals are inputted from at least one of operating levers 15a, 15b, 15c, and 15d thereto. When it is detected that at least one of the lower end parts of the plurality of jacks is brought into contact with the ground by the jack ground-contact detectors 82a, 82b, 82c, and 82d, the operation of the parking assisting device 50 is controlled to brake both the front wheels and rear wheels. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a work vehicle provided with a plurality of jacks for lifting and supporting a vehicle body adjacent to the front and rear wheels on a vehicle body having a front wheel and a rear wheel.

  An example of the work vehicle is an aerial work vehicle. In a work vehicle such as an aerial work vehicle, it is generally provided that left and right jacks are provided on the front and rear of the vehicle body, and the jack is extended to support the vehicle body in order to ensure the stability of the vehicle body during work. Are known. In such work vehicles, either the front wheel or the rear wheel (usually the rear wheel) is braked by the parking brake, and when the vehicle body is lifted and supported by extending the jack, the rear wheel etc. Extend the jack while the vehicle is braked and stopped.

  When extending the jack in this way, if the rear wheel side that is being braked by the parking brake is lifted and supported by the jack first, the front part of the vehicle body is supported by the front wheel that is not being braked. If the rear wheel side jack is extended first on an inclined ground, only the non-braking front wheel is grounded and rotated, and the vehicle may move freely along the slope.

For this reason, an auxiliary braking device that can brake both the front wheels and the rear wheels when the jack is extended to support the vehicle body is employed. The auxiliary braking device is configured to perform a braking operation on the front and rear wheels by depressing a brake pedal while pressing an auxiliary braking operation switch provided in the driving cabin.
Japanese Utility Model Publication No. 2-18764

  However, because the front and rear wheels are braked and released by the auxiliary braking device manually (that is, based on the operator's intention), for example, after being braked by the parking brake as described above. If the front and rear wheels are braked accidentally by the auxiliary braking device while the wheel side is lifted and supported by the jack first, there is a risk that the vehicle will move freely along the slope. There was a risk that safety would be reduced.

  This invention is made | formed in view of such a problem, and it aims at providing the work vehicle which improved the safety | security in jack work.

  In order to achieve such an object, the work vehicle according to the first aspect of the invention has a front wheel and a rear wheel, and is provided adjacent to the vehicle body that can travel using the rotational driving force of the engine, and the front wheel and the rear wheel, respectively. A plurality of jacks that use the rotational driving force of the engine to lift and support the vehicle body, a power take-off mechanism that extracts the rotational driving force of the engine to the jack side, and an operation for turning on and off the power take-off mechanism. Power take-off actuating means, jack operating means for operating a plurality of jacks, jack ground detecting means for detecting whether or not the lower ends of the plurality of jacks are in contact with the ground, and jack operating means are operated. Jack operation detecting means for detecting whether or not, an auxiliary braking device for braking both front and rear wheels, and jack grounding detecting means When it is detected that the lower end portion of the jack is in a non-grounded state, and an ON operation signal is input from the power take-off operation unit, and it is detected that the jack operation unit is operated by the jack operation detection unit. Controls the operation of the auxiliary braking device so as to brake both the front wheels and the rear wheels, and when the jack contact detection means detects that at least one of the lower ends of the plurality of jacks is in contact with the ground. And a controller for controlling the operation of the auxiliary braking device so as to brake both the front wheels and the rear wheels.

  In addition, a work vehicle according to a second aspect of the invention includes a vehicle body having a front wheel and a rear wheel that can travel, a plurality of jacks that are respectively provided adjacent to the front wheel and the rear wheel to lift and support the vehicle body, Jack operation means for operating the jack, jack ground detection means for detecting whether or not the lower ends of a plurality of jacks are in contact with the ground, and jack operation detection for detecting whether the jack operation means has been operated Means, an auxiliary braking device that brakes both the front wheels and the rear wheels, and a jack contact detection means that detects that at least one of the lower ends of the plurality of jacks is in contact with the ground. The operation of the auxiliary braking device is controlled so that both brakes are braked, and it is detected by the jack grounding detection means that the lower ends of all jacks are in a non-grounded state. And a controller that controls the operation of the auxiliary braking device so as to release the braking on the front wheels and the rear wheels when the jack operation detecting means detects that the jack operating means is in a non-operating state. The

  According to the first aspect of the present invention, the controller brakes both the front wheel and the rear wheel when it is detected by the jack contact detection means that at least one of the lower ends of the plurality of jacks is in contact with the ground. In order to control the operation of the auxiliary braking device, the braking force is secured in all the front and rear wheels when one jack is grounded regardless of the operation of the power take-off operating means and the jack operating means. It can prevent reliably that it moves, and can improve the safety | security in jack work.

  According to the second invention, the controller detects that the lower end of all jacks is in the non-grounded state by the jack grounding detecting means, and the jack operating means is in the non-operating state by the jacking operation detecting means. In the same manner, in order to control the operation of the auxiliary braking device so as to release the braking on the front wheels and the rear wheels, the braking force is applied to all the front and rear wheels in a state where even one jack is grounded. Therefore, it is possible to more reliably prevent the vehicle from moving without permission and to improve the safety in jacking.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows an aerial work vehicle 1 that is an example of a work vehicle according to the present invention. The aerial work vehicle 1 has a driving cabin 2a at the front part of the vehicle body 2, and a pair of left and right front wheels 3a and a pair of left and right rear wheels disposed at the lower part of the driving cabin 2a and the rear part of the vehicle body 2 in the left-right direction. A ring 3b is provided. The pair of front wheels 3a are rotatable, and the pair of rear wheels 3b are provided so as to be braked by operation of a parking brake lever 13 provided in the driving cabin 2a. The parking brake lever 13 is operated by the driver, and only the rear wheel 3b is braked by the operation of the parking brake lever 13. However, once the operation is performed, the parking brake lever 13 is maintained in a braking state unless it is released.

  Also, a left front jack 10a and a right front jack (not shown) are disposed on the rear side of the left and right front wheels 3a, and a left rear jack 10b and a right rear jack 10d are disposed on the rear side of the left and right rear wheels 3b. . The left front jack 10a has a left front jack cylinder 11a, the right front jack has a right front jack cylinder 11c (see FIG. 1), the left rear jack 10b has a left rear jack cylinder 11b, and the right rear jack 10d has a right rear jack. Each cylinder 11d is built in, and when these jack cylinders 11a, 11b, 11c, and 11d extend and contract, the front and rear, right and left jacks 10a, 10b, and 10d are configured to expand and contract, respectively. The left front jack 10a, the right front jack, the left rear jack 10b, and the right rear jack 10d are a plurality of jacks according to the present invention.

  On the vehicle body 2, a turntable 4 driven by a turn motor (hydraulic motor) (not shown) and configured to be horizontally turnable is disposed. A base 5 is pivotally connected to the swivel 4 and a boom 5 is attached. The boom 5 is moved up and down by a hoisting cylinder 6. The boom 5 is configured such that a proximal boom 5a, an intermediate boom 5b, and a distal boom 5c are combined in a nested manner, and can be expanded and contracted by a built-in telescopic cylinder 7.

  The tip boom 5c has a boom head 5d at the tip, and is pivotally connected to the boom head 5d and attached to the support member 8 so as to be swingable up and down. The support member 8 has a vertical post portion (not shown), and swinging control of the support member 8 is performed by a leveling cylinder (not shown) disposed between the boom head 5d and the support member 8. Regardless of whether the boom 5 is raised or lowered, the support member 8 is controlled to swing so that the vertical post portion always extends vertically. The work table 9 is attached to the vertical post portion that is always held vertically in such a manner that the work table 9 can be swung horizontally (swing freely), and the work table 9 is always held horizontally regardless of the ups and downs of the boom 5.

  The hoisting cylinder 6, the telescopic cylinder 7, the left front jack cylinder 11a, the right front jack cylinder 11c, the left rear jack cylinder 11b, and the right rear jack cylinder 11d described above are driven using hydraulic pressure. A power take-off mechanism PTO (see FIG. 1) that drives a hydraulic pump P by taking out a part of its output (rotational driving force) from the engine E (see FIG. 1) is attached to the front part. That is, the front jack 10a and the rear jacks 10b and 10d are expanded and contracted using the rotational driving force of the engine E, and the boom 5 is similarly moved up and down and expanded and contracted.

  Further, a power take-off switch 14 (see FIG. 1) for turning on / off the power take-off mechanism PTO, that is, driving or stopping the hydraulic pump P, is provided in the driver's seat in the driving cabin 2a. The power take-off switch 14 is a power take-off actuating means in the present invention.

  A jack operating device 15 for manually operating the front, rear, left and right jacks 10a, 10b, and 10d is provided at the rear end of the vehicle body 2. As shown in FIG. 3, the jack operation device 15 is disposed between a pair of tail lamps 16 disposed at the rear end of the vehicle body 2, and includes four operation levers 15a, 15b, 15c, 15d. That is, the jack operating device 15 includes, from the left side, a left front operating lever 15a for operating the left front jack 10a, a left rear operating lever 15b for operating the left rear jack 10b, and a right front operating lever for operating a right front jack (not shown). 15c and a right rear operation lever 15d for operating the right rear jack 10d.

  The operation levers 15a, 15b, 15c, and 15d are tiltable in the front-rear direction of the vehicle body 2, and the corresponding jack expands when tilted to the front, and the corresponding jack contracts when tilted to the rear. It is configured. Further, when each operation lever 15a, 15b, 15c, 15d is in a non-operation state, it is configured to automatically return to the vertical neutral position. The jack operating device 15 is a jack operating means in the present invention.

  Next, the brake system of the aerial work vehicle 1 will be described with reference to FIG. This brake system includes a parking brake (not shown) that brakes the rear wheel 3b by operating the parking brake lever 13 described above, a main braking device 20 that can brake both the front wheel 3a and the rear wheel 3b, and the auxiliary in the present invention. It is mainly composed of a parking assist device 50 that is a braking device. The main braking device 20 includes a front wheel brake 21 capable of braking the front wheel 3a, a rear wheel brake 22 capable of braking the rear wheel 3b, a brake pedal 23 provided in the driving cabin 2a, and a depression operation of the brake pedal 23. The brake booster 24 assists the brake, the brake fluid tank 25 that supplies the brake fluid to the wheel brakes 21 and 22, and pressurizes the brake fluid according to the depression amount (operation amount) of the brake pedal 23 (generates the brake pressure). ) Mainly composed of the brake master cylinder 26.

  A vacuum tank 27 and a vacuum pump 28 driven by the engine E are connected to the brake booster 24, and a predetermined negative pressure is generated in the brake booster 24 using the vacuum tank 27 and the vacuum pump 28. When the brake pedal 23 is depressed, a force larger than the depression force can be applied to the brake master cylinder 26. A load sensing valve 29 for controlling the brake pressure according to the vehicle (loading) weight is provided in the pipe line 32 connecting the brake master cylinder 26 and the rear wheel brake 22.

  In the main braking device 20 configured as described above, when the brake pedal 23 is depressed, the brake master is set in the pipeline 31 connecting the brake master cylinder 26 and the front wheel brake 21 and the pipeline 32 connecting the rear wheel brake 22. Brake fluid is pressurized by the cylinder 26 according to the depression amount (operation amount) of the brake pedal 23, and brake pressure is generated. Then, the front wheel brake 21 and the rear wheel brake 22 are operated using this brake pressure, and the front wheel 3a and the rear wheel 3b are braked.

  The pipe 31 is provided with a front brake control valve 41 and a first pressure switch 43, and the pipe 32 is provided with a rear brake control valve 42, and these are added to the configuration of the main braking device 20. A work braking device 40 is configured. The work brake device 40 is operated by depressing the brake pedal 23 while pressing a work brake device operation switch (not shown) provided in the operation cabin 2a, and is detected by the first pressure switch 43. When the pressure of the brake fluid reaches a predetermined pressure, the brake control valves 41 and 42 are actuated to close the pipes 31 and 32, and the brake pressures of the wheel brakes 21 and 22 are maintained to brake the front wheels 3a and the rear wheels 3b. It has come to be. In this state, by pressing the work brake operation switch again, the operation of each brake control valve 41, 42 (that is, the operation of the work brake device 40) is released so that the main brake device 20 can be used. It has become.

  The parking assist device 50 has a configuration in which a brake actuator 51 provided in the pipeline 32 is added to the configuration of the main braking device 20. As shown in FIG. 5, the brake actuator 51 includes a piston 52, a piston housing 53 in which the piston 52 is reciprocally movable, and connected to the front and rear wheel brakes 21, 22, an electric motor 54, and an electric motor 54. And a driving force transmitting portion 55 that converts the rotational force of the motor into a driving force of the piston and transmits it to the piston. In addition, the pipe line which connects the front wheel brake 21 and the piston accommodating part 53 is abbreviate | omitted in FIG.

  The piston 52 is housed in one end side in the piston housing part 53 so as to be able to reciprocate. The piston 52 moves toward one end side of the piston housing part 53 so that the brake fluid can be pressurized. A relief hole 52 a is formed at the other end of the piston 52 so as not to interfere with the bolt 58 of the driving force transmission portion 55.

  The driving force transmission unit 55 is mainly composed of a bolt 58 that is rotationally driven by the electric motor 54 via gears 56 and 57, and a nut 59 that is screwed into the bolt 58 (to be a right screw) and adjacent to the piston 52. It is comprised and is arrange | positioned by the other end side in the piston accommodating part 53. FIG. A nut housing portion 53a that matches the shape of the nut 59 is formed on the other end side (inside) of the piston housing portion 53, and the nut 59 is housed so as to be slidable without rotating. As a result, the nut 59 can be slid without rotating in the nut housing portion 53 a as the bolt 58 rotates, and the rotational force of the electric motor 54 is propelled by the piston 52 (by the driving force transmission portion 55). It can be converted into force and transmitted to the piston 52.

  Further, a spring 60 is disposed in the gap between the piston 52 and the piston housing portion 53 so as to urge the piston 52 in the direction of moving to the other end side in the piston housing portion 53. Further, a second pressure switch 61 that detects the pressure of the brake fluid is disposed on one end side of the piston accommodating portion 53, and a limit switch 62 that detects the nut 59 is disposed on the other end side of the piston accommodating portion 53. Is provided.

  In the parking assist device 50 configured as described above, the electric motor 54 rotates forward in response to a braking operation signal from a controller (details will be described later) (rotates clockwise as viewed from the left in FIGS. 5 and 6). Then, as the bolt 58 rotates, the nut 59 slides toward one end of the piston housing portion 53. Then, as shown in FIG. 6, the piston 52 is pressed by the nut 59, slides toward one end of the piston housing portion 53 against the biasing force of the spring 60, and pressurizes the brake fluid to generate the brake pressure. .

  When the front wheel brake 21 and the rear wheel brake 22 are operated using this brake pressure, and the brake fluid pressure detected by the second pressure switch 61 reaches a predetermined pressure, the rotation of the electric motor 54 is stopped. The piston 52 is fixed and held at the stop position by the driving force transmission portion 55, and the brake pressures of the wheel brakes 21 and 22 are held to brake the front wheel 3a and the rear wheel 3b. Thereby, since the parking assistance apparatus 50 can be operated only by supply of electric power regardless of the operation of the engine E, the safety of the aerial work vehicle 1 can be further improved.

  On the other hand, in the operating state of the parking assist device 50 as shown in FIG. 6, the electric motor 54 rotates in reverse (in response to the braking release signal from the controller (details will be described later) when viewed from the left in FIGS. When the bolt 58 rotates, the nut 59 slides toward the other end side of the piston housing portion 53. Then, the piston 52 receives the urging force of the spring 60 and slides to the other end side of the piston accommodating portion 53, and the pressure of the brake fluid is reduced. As shown in FIG. 5, when the nut 59 is slid until it is detected by the limit switch 62, the rotation of the electric motor 54 is stopped and the piston 52 is fixedly held at the stop position by the driving force transmitting portion 55. The braking of 3a and the rear wheel 3b is released, and the main braking device 20 can be used.

  Next, a control system for the aerial work vehicle 1 that controls the operation of the parking assist device 50 will be described with reference to FIG. This control system is configured to operate the parking assist device 50 and the jack operation control valve 81 in response to a control signal from the controller 80. The controller 80 also controls the operation of a boom actuator (not shown) and the like, but the description thereof is omitted.

  The controller 80 includes an operation signal from the jack operation device 15, that is, an operation signal from the left front operation lever 15a, an operation signal from the left rear operation lever 15b, an operation signal from the right front operation lever 15c, and a right rear operation. An operation signal is input from the lever 15d. As can be seen, the controller 80 has a function as jack operation detection means for detecting whether or not each of the operation levers 15a, 15b, 15c, 15d (jack operation device 15) is operated. The controller 80 also includes a ground signal from the left front jack ground detector 82a, a ground signal from the left rear jack ground detector 82b, a ground signal from the right front jack ground detector 82c, and a right rear jack ground detector. The ground signal from 82d and the operation signal from the power take-off switch 14 are input.

  The left front operation lever 15a, the left rear operation lever 15b, the right front operation lever 15c, and the right rear operation lever 15d output a jack extension operation signal when tilted to the front, and reduce the jack when tilted to the rear. Output a signal. The left front jack ground detector 82a, the left rear jack ground detector 82b, the right front jack ground detector 82c, and the right rear jack ground detector 82d are a left front jack 10a, a right front jack (not shown), a left rear jack 10b, and Provided in each of the right rear jacks 10d, a ground signal is output when the lower end of each jack comes into contact with the ground (hereinafter referred to as "grounded"). The left front jack ground detector 82a, the left rear jack ground detector 82b, the right front jack ground detector 82c, and the right rear jack ground detector 82d are jack ground detecting means in the present invention.

  The power take-off switch 14 outputs an on-operation signal when the on-operation of the power take-off mechanism PTO is performed, and outputs an off-operation signal when the off-operation of the power take-off mechanism PTO is performed. The jack operation control valve 81 opens or opens the oil passages of the hydraulic oil supplied from the hydraulic pump P driven by the engine E through the power take-off mechanism PTO to the jack cylinders 11a, 11b, 11c, and 11d, respectively. Cut off.

  In the control system for an aerial work vehicle 1 configured as described above, no operation signals are input to the controller 80 from all the operation levers 15a, 15b, 15c, 15d (or an OFF operation signal is input from the power take-off switch 14). The controller 80 does not output a jack operation signal to the jack operation control valve 81, and the operation of each jack cylinder 11a, 11b, 11c, 11d is not performed. That is, when all the operation levers 15a, 15b, 15c, and 15d (jack operation device 15) are not operated, all the jack cylinders 11a, 11b, 11c, and 11d do not expand and contract.

  Then, in a state where the parking brake (not shown) is activated, an operation signal is input to the controller 80 from at least one of the operation levers 15a, 15b, 15c, 15d, and an on operation signal is received from the power take-off switch 14. In the case of input, the controller 80 outputs a jack operation signal to the jack operation control valve 81, and the operation (extension or contraction) of the jack cylinder corresponding to the tilted operation lever (front or rear) is performed. ) Is performed. That is, when at least one of the operation levers 15a, 15b, 15c, 15d (jack operation device 15) is operated, the jack cylinder corresponding to the operation lever tilted (front or rear) is operated. Performs expansion and contraction according to the tilting direction of the lever.

  In addition, the controller 80 does not receive ground signals from all jack ground detectors 82a, 82b, 82c, and 82d, and does not receive operational signals from all the operating levers 15a, 15b, 15c, and 15d (or power take-off). When an off operation signal is input from the switch 14, the controller 80 does not output a braking operation signal to the parking assist device 50, and the parking assist device 50 does not perform a braking operation. That is, when the jack operation is not performed when the lower ends of all the jacks are not grounded, the parking assist device 50 does not operate, and the main braking device 20 (or parking brake) is used for braking the front and rear wheels. .

  The controller 80 does not receive ground signals from all jack ground detectors 82a, 82b, 82c, and 82d, and receives an ON operation signal from the power take-off switch 14, and controls the operation levers 15a, 15b, 15c, When an operation signal is input from at least one of 15d, the controller 80 outputs a braking operation signal to the parking assist device 50, and controls the parking assist device 50 to perform the braking operation. That is, it is detected by the jack ground detectors 82a, 82b, 82c, and 82d that the lower end portions of all jacks are not grounded, and an ON operation signal is input from the power take-off switch 14 (jacks). When the controller 80 (as an operation detecting means) detects that at least one of the operation levers 15a, 15b, 15c, 15d has been operated, the parking assist device brakes both the front wheel 3a and the rear wheel 3b. 50 operations are controlled.

  On the other hand, when a ground signal is input to the controller 80 from at least one of the jack ground detectors 82a, 82b, 82c, 82d, the controller 80 outputs a braking operation signal to the parking assist device 50, and the parking assist device. 50 is controlled to perform a braking operation. That is, when it is detected by the jack ground detectors 82a, 82b, 82c, 82d that at least one of the lower ends of the front, rear, left and right jacks is in contact with the ground, the power take-off switch 14 and the jack operating device 15 Regardless of the operation, the operation of the parking assist device 50 is controlled so as to brake both the front wheel 3a and the rear wheel 3b.

  In the state where the parking assist device 50 is operated so as to brake both the front and rear wheels as described above, no grounding signal is input to the controller 80 from all the jack grounding detectors 82a, 82b, 82c, 82d, and When no operation signal is input from all the operation levers 15a, 15b, 15c, 15d, the controller 80 outputs a braking release signal to the parking assistance device 50, and the parking assistance device 50 performs an operation of releasing the braking of the front and rear wheels. Control to do. That is, it is detected by the jack ground detectors 82a, 82b, 82c, and 82d that the lower ends of all jacks are not grounded, and the controller 80 (as jack operation detecting means) detects all the operating levers. When it is detected that 15a, 15b, 15c, 15d (jack operating device 15) is in a non-operating state, the operation of the parking assist device 50 is controlled so as to release the braking on the front wheel 3a and the rear wheel 3b. .

  As a result, the braking force is secured in all front and rear wheels when one jack is in contact with the ground, so it is possible to more reliably prevent the vehicle from moving without permission and improve the safety in jacking. Can be made. Further, when the jack operation is stopped until the jack is grounded, the braking of the front and rear wheels by the parking assist device 50 is released, so that the vehicle can be moved by a small amount even in a state where the jack extends without being grounded. Thus, work efficiency in jacking work can be improved. Further, since the jack ground detector is often attached to the jack as a standard, the safety in jacking work can be improved without causing a significant increase in manufacturing cost.

  According to the aerial work vehicle 1 configured as described above, the controller 80 causes the jack ground detectors 82a, 82b, 82c, and 82d to contact at least one of the lower end portions of the front and rear (right and left) jacks with the ground. When contact is detected, the operation of the parking assist device 50 is controlled so that both the front wheel 3a and the rear wheel 3b are braked, regardless of the operation of the power take-off switch 14 and the jack operation device 15. When one jack is in contact with the ground, braking force is secured in all front and rear wheels, so that it is possible to more reliably prevent the vehicle from moving without permission and improve safety in jacking work. it can.

  Further, the controller 80 detects that the lower ends of all jacks are not grounded by the jack ground detectors 82a, 82b, 82c, and 82d, and the controller 80 (as jack operation detecting means) When it is detected that the jack operating device 15 is in the non-operating state, the operation of the parking assist device 50 is controlled so as to release the braking on the front wheel 3a and the rear wheel 3b. However, since the braking force is secured in all the front and rear wheels in a grounded state, it is possible to more reliably prevent the vehicle from moving without permission and improve the safety in jacking.

  In the above-described embodiment, the aerial work vehicle 1 has been described as an example of the work vehicle according to the present invention. However, the present invention is not limited to this example. The present invention can be applied to any work vehicle provided with a plurality of jacks that lift and support the vehicle body adjacent to the front and rear wheels on a vehicle body that has wheels.

In the above-described embodiment, the parking assist device 50 is used as the auxiliary braking device in the present invention.
However, the present invention is not limited to this, and the work braking device 40 may be used. Note that when the work braking device 40 is used, a brake pedal driving means for driving (swinging) the brake pedal 23 in accordance with a control signal from the controller is necessary.

  Furthermore, in the above-described embodiment, the operation of the parking assist device 50 is controlled according to whether or not the jack is grounded. However, the present invention is not limited to this, and changes in the load acting on the front wheels and the rear wheels ( The operation of the parking assist device 50 may be controlled in accordance with the determination that the vehicle body is lifted when the load acting on the front and rear wheels is equal to or less than a predetermined load.

  In addition, when the jack storage detector that detects whether or not the jack is in the retracted state and the controller detects that all jacks are in the retracted state by the jack storage detector, the front wheel and When the operation of the parking auxiliary device (auxiliary braking device) is controlled so as to release the braking of the rear wheel, and it is detected that at least one of all jacks by the jack storage detector is in the non-retracted state The operation of the parking assist device (auxiliary braking device) may be controlled so as to brake both the front wheels and the rear wheels. In this way, it is possible to prevent the vehicle from moving while the jack is accidentally extended.

  Furthermore, in the above-described embodiment, the controller 80 to which the operation signal from the jack operation device 15 is input is used as the jack operation detection means in the present invention. However, the present invention is not limited to this. A switch that detects the movement of the jack operation device (such as a limit switch) or a switch that detects the movement of the tip of the valve spool connected to the operation lever can be used to detect whether or not the jack operation device (means) has been operated. If it is.

It is a block diagram which shows the structure of the control system comprised by the work vehicle which concerns on this invention. It is a perspective view of the said working vehicle. It is an enlarged view of the jack operation apparatus comprised in the said work vehicle. It is a schematic diagram which shows the structure of the brake system comprised by the said work vehicle. It is sectional drawing of a brake actuator. It is sectional drawing which shows the operating state of a brake actuator.

Explanation of symbols

1 High-altitude work vehicle 2 Car body (2a Driving cabin)
3a front wheel 3b rear wheel 10a left front jack 10b left rear jack 10d right rear jack 14 power take-off switch (power take-off actuating means)
15 Jack operation device (jack operation means)
20 main brake device 40 work brake device 50 parking assist device (auxiliary brake device)
80 Controller 82a Left front jack ground detector (jack ground detection means)
82b Left rear jack ground detector (jack ground detection means)
82c Right front jack ground detector (jack ground detection means)
82d Right rear jack ground detector (jack ground detection means)
E engine PTO power take-off mechanism

Claims (2)

A vehicle body having front and rear wheels and capable of traveling using the rotational driving force of the engine;
A plurality of jacks provided adjacent to the front wheel and the rear wheel, respectively, that operate using the rotational driving force of the engine to lift and support the vehicle body;
A power take-off mechanism for extracting the rotational driving force of the engine to the jack side;
Power take-off actuating means for operating the power take-off mechanism to turn on / off;
Jack operating means for operating the plurality of jacks;
Jack grounding detection means for detecting whether or not lower end portions of the plurality of jacks are in contact with the ground;
Jack operation detecting means for detecting whether or not the jack operating means has been operated;
An auxiliary braking device for braking both the front wheel and the rear wheel;
It is detected by the jack ground detection means that the lower end portions of all the jacks are not grounded, and an ON operation signal is input from the power take-off operation means, and the jack operation detection means performs the jack operation. When it is detected that the means is operated, the operation of the auxiliary braking device is controlled so as to brake both the front wheel and the rear wheel, and the jack grounding detecting means controls the lower end portions of the plurality of jacks. And a controller for controlling the operation of the auxiliary braking device so as to brake both the front wheel and the rear wheel when it is detected that at least one of the wheels touches the ground. Work vehicle. A vehicle body capable of traveling with front and rear wheels;
A plurality of jacks provided adjacent to the front wheel and the rear wheel to lift and support the vehicle body;
Jack operating means for operating the plurality of jacks;
Jack grounding detection means for detecting whether or not lower end portions of the plurality of jacks are in contact with the ground;
Jack operation detecting means for detecting whether or not the jack operating means has been operated;
An auxiliary braking device for braking both the front wheel and the rear wheel;
When the jack contact detection means detects that at least one of lower end portions of the plurality of jacks is in contact with the ground, the auxiliary braking device is actuated to brake both the front wheel and the rear wheel. The jack grounding detecting means detects that the lower end portions of all the jacks are in a non-grounded state, and the jack operation detecting means detects that the jack operating means is in a non-operating state. And a controller for controlling the operation of the auxiliary braking device so as to release the braking on the front wheels and the rear wheels.

Images