JP2015048028A - Jack operation controller for work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent rear jacks from being extended without front wheels floating from a ground surface at jack-up operation for a work vehicle.SOLUTION: A work vehicle provided with front and rear jacks 3A and right and left jacks 3B are provided with: vehicle body inclination angle detecting means 15; vehicle body inclination angle storing means 41 that stores a vehicle body inclination angle at a position where a jack-up operation is performed; vehicle body-ground angle storing means 42 that has previously stored a vehicle body-ground angle with rear wheels 12B grounded and front wheels 12A separated from the ground surface; calculating means 43 that adds the stored vehicle body inclination angle with the stored vehicle body-ground angle; comparing means 44 that compares a current vehicle body inclination angle with a composite angle determined by the addition by the calculating means; and rear jack extending means 45 that when the comparing means determines that the current vehicle body inclination angle is smaller than the composite angle, performs a control so that an operation of extending the rear jacks is prohibited, thereby prohibiting the operation of extending the rear jacks of causing the front wheels 12A to be grounded.

Description

  The present invention relates to a jack operation control device for supporting (jacking up) a work vehicle with a jack such as a crane truck or an aerial work vehicle in a state where the work vehicle is lifted from the ground with each jack.

  FIGS. 1A to 1C show an aerial work vehicle as an example of a work vehicle. The aerial work vehicle includes a front and rear, left and right (four) wheels 12A and 12B on a vehicle body 11. Front / rear and left / right (four) jacks 3 </ b> A and 3 </ b> B are provided, and the work machine 2 is mounted on the vehicle body 11. The work machine 2 is configured by attaching a bucket 22 for boarding an operator to the tip of a telescopic boom 21 that can turn and undulate. The front wheels 12A, the rear wheels 12B, the front jacks 3A, and the rear jacks 3B have a pair on the left and right, respectively, but are shown as singular in order to avoid complicated description.

  In this type of work vehicle equipped with a jack, when working with the work machine 2 mounted on the upper part of the vehicle body 11, the vehicle 1 is levitated and supported from the ground G by the front and rear, left and right (four) jacks 3A and 3B. However, most of this type of work vehicle is jacked in the order shown in FIGS. 1A to 1C because only the rear wheel 12B of the vehicle 1 is braked by the parking brake. The operation is performed.

  First, the state of FIG. 1A is a work vehicle posture before jack-up, and the rear wheel 12B is braked by a parking brake, but the front wheel 12A remains in a rolling free state. In the state before the jack-up shown in FIG. 1A, the front jack 3A and the rear jack 3B are fully contracted, and the front wheel 12A and the rear wheel 12B are in contact with the ground G, respectively. The front and rear jacks 3A and 3B are provided with ground detectors 32A and 32B for detecting when the ground plates 31A and 31B are grounded to the ground G. The jacks 3A and 3B are connected to the jacks 3A and 3B. When the ground planes 31A and 31B are grounded to the ground G, ground detection signals are output from the respective ground detectors 32A and 32B to the controller.

  In order to jack up from the state shown in FIG. 1 (A), the front jack 3A is first extended to lift the front wheel 12A from the ground G as shown in FIG. 1 (B). In the state shown in FIG. 1B, the grounded rear wheel 12B is braked by the parking brake, so the work vehicle does not escape (move) back and forth.

  When the rear jack 3B is extended from the state of FIG. 1 (B) and the rear wheel 12B is lifted from the ground G as shown in FIG. 1 (C), the front / rear / left / right (four) jacks 3A. , 3B, the entire work vehicle can be supported in a state of being lifted from the ground G. In the following description, the fact that the wheels 12 </ b> A and 12 </ b> B float from the ground G may be referred to as ground cutting.

  By the way, if the jack-up operation is performed in the normal order shown in FIGS. 1A to 1C, the work vehicle will not accidentally run away, but the operator makes a mistake in the jack operation order. When the rear jack 3B is extended from the state of A) (the front wheel 12A remains in contact with the ground), the rear wheel 12B that is braked by the parking brake while the rolling front wheel 12A remains in contact with the ground Therefore, if the place where the jack-up is performed is an inclined place, the front wheel 12A may roll and the work vehicle may accidentally escape.

  Therefore, as a technique for preventing the work vehicle from running away due to such a mistake in the operation order of the jack, there has been conventionally disclosed in Japanese Utility Model Publication No. 5-41092 (Patent Document 1).

  The outline of the work vehicle escape prevention technology (the name of the device: the outrigger operation safety device of the work vehicle) of this known example (Patent Document 1) is shown in FIGS. 2 (A) to (C). Is detecting the grounding state of the grounding plate 31A of the front jack 3A by the grounding detector 32A of the front jack 3A, and only when the ON signal is issued from the grounding detector 32A of the front jack 3A, Extension operation | movement is accept | permitted with respect to the rear jack 3B. In other words, if the grounding plate 31A of the front jack 3A is in a non-grounded state (the grounding detector 32A is in an OFF state), even if the rear jack 3B is extended, the extension operation of the rear jack 3B is prohibited. In addition, since the rear wheel 12B (parking brake is applied) is maintained in a grounded state, the work vehicle does not run away even when the jackup is performed on an inclined ground.

  By the way, in the work vehicle escape prevention technology of the known example (Patent Document 1), when the ground plate 31A of the front jack 3A contacts the ground G as shown in FIG. Although 32A outputs an ON signal (rear jack extension allowance signal), the front wheel 12A may still be grounded while the ground plate 31A is grounded.

Japanese Utility Model Publication No. 5-41092

  And in the work vehicle escape prevention technique of the said well-known example (patent document 1), in the state shown in FIG. 2 (B) (the state where the grounding plate 31A of the front jack 3A and the front wheel 12A are both in contact with the ground), the operator can If the rear jack 3B is extended while overlooking the ground contact state of the rear wheel 12B, the rear wheel 12B will float (ground) from the ground G while the front wheel 12A remains grounded as shown in FIG. Sometimes, when the jack-up execution place is inclined forward and backward, the front wheel 12A does not have a braking force, so that the work vehicle may escape to the downward inclination side.

  Thus, in the work vehicle escape prevention technology of the above-described known example (Patent Document 1), the extension operation of the rear jack 3B is prohibited when the grounding plate 31A of the front jack 3A is not in the grounding state, but is shown in FIG. As described above, when the grounding plate 31A of the front jack 3A and the front wheel 12A are both in contact with each other, the rear jack extension operation is allowed, so that the rear wheel 12B is grounded while the front wheel 12A is grounded due to an erroneous operation by the operator ( There is a danger that the work vehicle may run away.

  Therefore, in order to improve the problems of the above-mentioned known examples, the present invention provides a jack operation control for a work vehicle in which the rear jack cannot be extended unless the front wheels are reliably lifted (ground cut) from the ground. The object is to provide a device.

  The present invention has the following configuration as means for solving the above problems.

[Invention of Claim 1 of the Present Application]
The invention of claim 1 of the present application is directed to a jack operation control device in a work vehicle having a front and rear, left and right wheels and front and rear and left and right jacks on a vehicle body, and further having a parking brake for braking a rear wheel. It is.

  In addition, the work vehicle applied in this application is intended to support the entire work vehicle from the ground by using jacks provided on the front and rear, left and right of the vehicle body, such as an aerial work vehicle and a crane vehicle. ing.

  The jack operation control device according to the first aspect of the present invention includes a vehicle body tilt angle detecting means for detecting a vehicle body tilt angle with respect to the front-rear horizontal direction, and the vehicle body tilt angle in a state where both front and rear wheels are grounded at a jack-up execution place. Vehicle body inclination angle storage means for storing the vehicle body inclination angle at the time of both-wheel contact detected by the detection means; vehicle body ground angle storage means for previously storing the vehicle body ground angle in a state where the rear wheel is grounded and the front wheel is separated from the ground; Calculating means for adding the stored vehicle body inclination angle stored by the vehicle body inclination angle storage means and the stored vehicle body ground angle stored by the vehicle body ground angle storage means, and detecting by the vehicle body inclination angle detection means at the jack up place. Comparing means for comparing the current vehicle body inclination angle with the composite angle added by the calculating means, and the current vehicle body inclination by the comparing means When it is determined that the degree is smaller than the composite angle, the extension operation of the rear jack is prohibited. On the other hand, when the comparison means determines that the current vehicle body inclination angle is equal to or greater than the composite angle, the rear jack And a rear jack extension control means for controlling so as to allow the extension operation.

  The work vehicle used in claim 1 of the present application also jacks up the work vehicle in the following procedure.

  First, after stopping the work vehicle at the jack-up execution place, the parking brake is operated to brake the left and right rear wheels. At this time, the left and right front wheels remain free to roll.

  Next, the left and right front jacks are extended, and the left and right front wheels are floated (ground cut) from the ground. This front jack extending operation is normally performed until the front wheels are reliably grounded (separated from the ground). In this state where the front wheel is grounded, the rear wheel braked by the parking brake remains in contact with the ground, so the work vehicle does not move (runaway) carelessly.

  Subsequently, the left and right rear jacks are extended, and the left and right rear wheels are lifted (ground cut) from the ground to jack up the entire work vehicle.

  By the way, if the procedure for jacking up this type of work vehicle is wrong, there is a risk that the work vehicle may run away in the downward inclination direction of the ground during the jack-up operation procedure. In other words, if the rear jack is extended with the front wheel in contact with the ground, the rear wheel with braking force is lifted from the ground (ground cutting), while the front wheel without braking force remains in contact with the ground. There is a risk of running away in the downward slope direction of the ground. The extension operation of the rear jack in the state where the front wheel is in contact with the front wheel occurs even if the work vehicle escape prevention technique of the publicly known example (Patent Document 1) is provided as described in the background art section. obtain.

  Accordingly, the jack operation control device according to the first aspect of the present invention includes each of the above-described configurations (vehicle body tilt angle detection means, vehicle body tilt angle storage means, vehicle body ground angle storage means, calculation means, comparison means, rear jack extension control means). And comparing the current vehicle body inclination angle detected by the vehicle body inclination angle detection means at the jack-up execution location by the comparison means with the combined angle added by the arithmetic means, and finally the rear jack extension control means This function prevents the rear jack from extending when the front wheel is in contact with the ground, while allowing the rear jack to extend only when the front wheel is lifted from the ground. To do. A specific control method and function by the jack operation control device of the present application will be described in detail in the section of an embodiment described later.

[Invention of claim 2 of the present application]
The invention of claim 2 of the present application employs a combined angle storage means in place of the vehicle body inclination angle storage means in the jack operation control device of claim 1 described above.

  That is, the jack operation control device according to the second aspect of the present invention includes a vehicle body inclination angle detection means (the same as that of the first aspect), a vehicle body ground angle storage means (the same as that of the first aspect), and a jack-up execution place. An arithmetic means for adding the vehicle body inclination angle detected by the vehicle body inclination angle detection means when the front and rear wheels are in contact with each other and the stored vehicle body ground angle stored in the vehicle body ground angle storage means; and The composite angle storage means for storing the added composite angle is compared with the current vehicle body tilt angle detected by the vehicle body tilt angle detection means at the jack-up execution location and the stored composite angle stored by the composite angle storage means. When the comparison means and the comparison means determine that the current vehicle body inclination angle is smaller than the stored composite angle, the extension operation of the rear jack is prohibited. On the other hand, when the comparison means determines that the current vehicle body inclination angle is greater than or equal to the stored composite angle, it is configured to include rear jack extension control means that controls to allow the rear jack to extend. Yes.

  In the jack operation control apparatus according to claim 2, the comparison means includes the current vehicle body inclination angle detected by the vehicle body inclination angle detection means at the jack-up execution location and the stored composite angle stored by the composite angle storage means. After the comparison, the rear jack extension control means finally prohibits the rear jack from extending when the front wheel is in contact with the ground, but only when the front wheel is floating (ground cutting) from the ground. It functions to allow the rear jack to extend.

[Invention of claim 3 of the present application]
The invention according to claim 3 of the present application is the jack operation control apparatus according to claim 1 or 2, wherein the vehicle body ground angle stored in the vehicle body ground angle storage means is such that the front jack is grounded and the rear jack extends to the stroke end. Even in such a state, the front wheel is set to have an angle larger than the angle at which the front wheel is separated from the ground.

  By the way, the invention of claim 3 has been made in consideration of the following background. That is, when the vehicle ground angle stored in the vehicle ground angle storage means is very small (when the rear wheel is grounded and the front jack is grounded with the front wheel slightly lifted from the ground) When the rear jack is extended to a large extent (for example, extended to the stroke end), the rear side of the vehicle body is largely lifted, so that the vehicle body is inclined so as to descend to the front side with the front jack grounding portion as a fulcrum. At that time, the front wheel on the front side of the front jack grounding part may slightly move down to ground the front wheel, but when the front wheel is grounded in this way, the grounding force by the front jack becomes weak, and the jack When the up execution place is an inclined place, the work vehicle may escape.

  Therefore, in the jack operation control apparatus according to the third aspect of the present invention, even if the front-side jack is grounded and the rear-side jack is extended to the stroke end, the front wheel is grounded. By setting the angle to be greater than or equal to the angle away from the front wheel, the front wheel is prevented from touching the ground even when the rear jack is fully extended while the front jack is grounded.

[Effect of the invention of claim 1 of the present application]
The jack operation control device according to the first aspect of the present invention comprises each configuration comprising vehicle body tilt angle detection means, vehicle body tilt angle storage means, vehicle body ground angle storage means, calculation means, comparison means, and rear jack extension control means. After comparing the current vehicle body inclination angle and the composite angle, the rear jack extension control means finally prohibits the rear jack from extending when the front wheel is in contact with the ground, while the front wheel The rear jack is configured to allow the extension operation only when floating (cutting ground) from the ground.

  Therefore, in the jack operation control device according to the first aspect of the present invention, even if the operator overlooks the front wheel grounding state and performs an erroneous operation (rear jack extension operation), the rear jack does not extend, so that the work vehicle may run away. There is an effect that it does not shift to a certain state (the front wheel is grounded and the rear wheel is in a floating state) (safety is ensured).

  According to the first aspect of the present invention, the rear jack extension control means outputs the rear jack extension prohibition signal because the current vehicle body inclination angle is added to the composite angle (the stored vehicle body inclination angle and the stored vehicle body ground angle by the comparison means). This state includes a state in which the front jack and the front wheel are both in contact with the ground, and is a problem that has been a concern for the above-mentioned known example (Patent Document 1). The point (when the front jack and the front wheels are both in contact with the ground is allowed to extend to the work vehicle by allowing the extension operation of the rear jack), so it is possible to secure further safety. There is also an effect.

[Effect of the invention of claim 2 of the present application]
The jack operation control device according to the second aspect of the present invention comprises each component comprising vehicle body inclination angle detection means, vehicle body ground angle storage means, calculation means, composite angle storage means, comparison means, and rear jack extension control means. After comparing the current vehicle body inclination angle with the stored composite angle, the rear jack extension control means finally prohibits the rear jack from extending when the front wheel is in contact with the ground, while the front wheel The rear jack is configured to allow the extension operation only when floating (cutting ground) from the ground.

  Therefore, the jack operation control device according to the second aspect of the invention can achieve the same effect as the first aspect.

[Effect of the invention of claim 3 of the present application]
The invention according to claim 3 of the present application is the jack operation control apparatus according to claim 1 or 2, wherein the vehicle ground angle stored in the vehicle ground angle storage means is in a state where the front jack is grounded and the rear jack is extended to the stroke end. However, it is characterized in that the front wheel is set to be larger than the angle at which it is separated from the ground.

  Therefore, in the jack operation control apparatus according to the third aspect of the present invention, even when the rear jack is extended to the stroke end while the front jack is grounded, the front wheel does not touch the ground. In addition to the above effect, there is an effect that even if the rear jack is extended to the maximum during the jack-up operation, the work vehicle does not shift to the escape state (further safety can be secured).

(A)-(C) are explanatory drawings of the general jack-up order of a work vehicle. (A)-(C) are the problem explanatory drawings of the working vehicle runaway prevention technique of a well-known example (patent document 1). It is a block diagram which shows the structure of the jack operation control apparatus of 1st Example of this application. It is a block diagram which shows the structure of the jack operation control apparatus of 2nd Example of this application. (A)-(C) are explanatory drawings of the jack-up order of the work vehicle controlled by the jack operation control apparatus of each Example of this application.

  Hereinafter, with reference to FIGS. 3 to 5, the jack operation control device for a working vehicle according to the present embodiment will be described. FIG. 3 is a block diagram of the jack operation control device according to the first embodiment corresponding to claim 1 of the present application. 4 shows a block diagram of a jack operation control apparatus according to a second embodiment corresponding to claim 2 of the present application, and FIGS. 5A to 5C show the jack operation control apparatus of FIGS. Shows the jack-up sequence to use.

  Since the work vehicle shown in FIGS. 5A to 5C is the same as the work vehicle shown in FIGS. 1A to 1C, the configuration of the work vehicle shown in FIGS. About, the description in FIG. 1 (A)-(C) is used. In addition, the same code | symbol is attached | subjected to FIG. 5 (A)-(C) the same part as FIG. 1 (A)-(C).

[First embodiment]
The jack operation control apparatus according to the first embodiment shown in FIG. 3 includes a vehicle body tilt angle detection means 15, a vehicle body tilt angle storage means 41, a vehicle body ground angle storage means 42, and a calculation means 43, each having functions to be described later. The comparison means 44 and the rear jack extension control means 45 are provided. The vehicle body inclination angle storage means 41, the vehicle body ground angle storage means 42, the calculation means 43, the comparison means 44, and the rear jack extension control means 45 are all stored in the controller 4.

  The vehicle body inclination angle detection means 15 (FIGS. 3 and 5) may be any device that can detect the inclination angle of the vehicle body 11 with respect to the front-rear horizontal direction, and even a dedicated angle detector attached to the vehicle body 11 can be used as a work vehicle. An existing angle detector (boom hoisting angle detector 15 in the example of FIGS. 5A to 5C) may be used. When the boom undulation angle detector 15 shown in FIGS. 5A to 5C is used as the vehicle body tilt angle detection means, the state in which the telescopic boom 21 is stored on the vehicle body 11 is a reference (“0 °”). ), And the inclination variation angle of the vehicle body 11 is measured.

  The vehicle body inclination angle storage means 41 (FIG. 3) is the vehicle body inclination angle detection means 15 in a state where the front and rear wheels 12A, 12B are in contact with the ground G at the place where jack-up is performed, as shown in FIG. The detected vehicle body inclination angle when the front and rear wheels are in contact with each other is stored. In this case, the vehicle body inclination angle detected by the vehicle body inclination angle detection means 15 reflects the inclination state of the ground G at the place where jack-up is performed. For example, when the ground inclination state is a horizontal state shown by a solid line in FIG. 5A (reference numeral G), the vehicle body inclination angle θ detected by the vehicle body inclination angle detection means 15 is 0 °. When the ground is tilted at a predetermined angle (θ ′) indicated by a chain line in FIG. 5A (reference symbol G ′), the vehicle body tilt angle detected by the vehicle body tilt angle detection means 15 is detected. Becomes θ− (or +) θ ′. Note that the vehicle body inclination angle θ displayed in FIG. 5A is represented by a line connecting the ground contact points of the front wheel 12A and the rear wheel 12B for easy understanding.

  The vehicle body ground angle storage means 42 (FIG. 3) stores in advance the vehicle body ground angle Δθ in a state where the rear wheel 12B is grounded and the front wheel 12A is separated from the ground G, as shown in FIG. 5B. is there. As shown in FIG. 5B, the vehicle body ground angle Δθ is set such that the rear wheel 12B is in a grounded state (the rear jack 3B is not grounded) and the front wheel 12A is separated from the ground G (the front jack 3A is extended and the front wheel is extended). The angle is such that the front wheel 12A does not come into contact with the ground G even if the rear jack 3B is extended from the lifted state) until the rear wheel 12B ascends as shown in FIG. In this embodiment, even if the storage vehicle ground angle Δθ corresponds to claim 3 of the present application and the rear jack 3B is extended to the stroke end as shown in FIG. 12A is set to an angle that does not contact the ground G. The vehicle body ground angle Δθ stored in the vehicle body ground angle storage means 42 is a constant determined by a test for each model of the work vehicle, and the vehicle body ground angle Δθ determined for each model is set in advance by the vehicle body ground angle of the controller 4. The data is stored in the storage means 42.

  The computing means 43 (FIG. 3) adds the stored vehicle body inclination angle θ stored in the vehicle body inclination angle storage means 41 and the stored vehicle body ground angle Δθ stored in the vehicle body ground angle storage means 42. Note that the combined angle (θ + Δθ) added by the calculation means 43 is described as X.

  The comparison means 44 (FIG. 3) compares the current vehicle body inclination angle θ1 detected by the vehicle body inclination angle detection means 15 with the combined angle X added by the calculation means 43 at the jack-up execution location. The current vehicle body inclination angle θ1 includes the inclination angle of the ground G and the ground angle of the work vehicle.

  The rear jack extension control means 45 (FIG. 3) performs the extension operation of the rear jack 3B when the comparison means 44 determines that the current vehicle body inclination angle θ1 is smaller than the composite angle X (θ1 <X). While the prohibiting signal (rear jack extension prohibiting signal 46) is output, when the comparison means 44 determines that the current vehicle body inclination angle θ1 is equal to or greater than the combined angle X (θ1 ≧ X), the rear jack 3B Is controlled so as to output a signal permitting the extension operation (post jack extension allowance signal 47).

  The work vehicle equipped with the jack operation control device of the first embodiment (FIG. 3) is also jacked up according to the procedure shown in FIGS. 5 (A) to 5 (C). Works as follows.

  The vehicle body ground angle storage means 42 in the controller 4 stores in advance a vehicle body ground angle Δθ in a state where the rear wheel 12B is grounded and the front wheel 12A is separated from the ground G (the state shown in FIG. 5B). Yes. The vehicle body ground angle Δθ stored in the vehicle body ground angle storage means 42 in the first embodiment is an angle that meets the condition of claim 3 of the present application. Moreover, the jack operation control apparatus shown in FIG. 3 is in an operable state when it is ready to start jackup.

  First, as shown in FIG. 5 (A), the work vehicle is stopped at the place where jack-up is performed (at this time, the rear wheel 12B is braked by the parking brake), and the vehicle body inclination angle in this state (when both front and rear wheels are grounded) is set. The vehicle body inclination angle detection unit 15 detects the vehicle body inclination angle θ, and the vehicle body inclination angle storage unit 41 stores the vehicle body inclination angle θ. Note that the vehicle body inclination angle θ at this time reflects the inclination angle of the ground G at the place where jack-up is performed. On the other hand, in the calculation means 43, the combined angle X (θ + Δθ) obtained by adding the stored vehicle body inclination angle θ stored in the vehicle body inclination angle storage means 41 and the storage vehicle body ground angle Δθ stored in the vehicle body ground angle storage means 42. Is calculated.

  In the state shown in FIG. 5A, that is, when both the front wheel 12A and the rear wheel 12B are in contact with the ground, the current vehicle body inclination angle θ1 detected by the vehicle body inclination angle detection means 15 and the calculation means 43 are used. The composite angle X (θ + Δθ) is compared by the comparison means 44, and the comparison result is θ1 <X, so the rear jack extension control means 45 outputs the rear jack extension inhibition signal 46. Therefore, in the state of FIG. 5A, even if the operator overlooks the ground contact state of the front wheel 12A and extends the rear jack 3B, the rear jack 3B does not extend carelessly (the rear wheel 12B does not float). No work vehicle escapes).

  Next, in order to jack up the work vehicle, first, as shown in FIG. 5B, the front jack 3A is extended by a predetermined length or more, and the front wheel 12A is lifted from the ground G to a predetermined height. The angle detection means 15 detects the current vehicle body inclination angle θ1 and outputs the detected value θ1 to the comparison means 44. The comparison means 44 outputs the combined angle X (θ + Δθ) from the calculation means 43 and the current vehicle body. The inclination angle θ1 is compared.

  When the comparison means 44 determines that the current vehicle body inclination angle θ1 is smaller than the combined angle X (θ1 <X), the rear jack extension control means 45 sends a signal for prohibiting the extension operation of the rear jack 3B ( The rear jack extension prohibiting signal 46) is output, and as a result, the rear jack 3B does not extend even if the operator mistakenly performs the rear jack extension operation. When the current vehicle body inclination angle θ1 is smaller than the combined angle X (θ1 <X) and the rear jack 3B is extended to the stroke end in FIG. 5B, the state shown in FIG. Although the trouble that the front wheel 12A comes in contact with the ground G (the work vehicle escapes when it is an inclined ground) occurs, the extension operation of the rear jack 3B is prohibited in the present application, so such a trouble does not occur.

  On the other hand, when the comparison means 44 determines that the current vehicle body inclination angle θ1 is equal to or greater than the combined angle X (θ1 ≧ X), the rear jack extension control means 45 allows the rear jack 3B to extend. A signal (rear jack extension allowance signal 47) is output, and as a result, the rear jack 3B can be extended by the rear jack extension operation by the operator.

  When the rear jack 3B is extended from the state shown in FIG. 5B with the rear jack extending operation permitted, the work vehicle tilts forward and downward with the grounding portion (the ground plate 31A) of the front jack 3A as a fulcrum. Even if the rear wheel 12B is lifted from the ground G and the rear jack 3B is extended to the stroke end at that time, the front wheel 12A is still separated from the ground G as shown in FIG. The car does not run carelessly.

  In the state shown in FIG. 5C, the front jack 3A does not extend to the maximum, and the work vehicle is slightly tilted downward from the front side. From this state, the front jack 3A is extended by a predetermined amount to remove the work vehicle. Maintain a horizontal position.

  As described above, when the jack operation control device of the first embodiment is adopted, the rear jack 3B is extended even if the rear jack extension operation is performed under the condition that the front wheel 12A is grounded by extending the rear jack 3B. Therefore, even if the jack extension operation is performed after the operator's erroneous operation (for example, overlooking the grounding state of the front wheel 12A), the danger of the work vehicle running away does not shift (safety is ensured). )

  In the jack operation control apparatus of the first embodiment, the rear jack extension control means 45 outputs the rear jack extension inhibition signal 46 because the comparison means 44 sets the current vehicle body inclination angle θ1 to the combined angle X (memory vehicle body). This is a case where it is determined that the angle is smaller than the inclination angle θ and the stored vehicle body ground angle Δθ). This state includes the state in which the front jack 3A and the front wheel 12A are both in contact with the ground. The problem that has been a concern for (Patent Document 1) can also be solved.

  Further, in the jack operation control apparatus of the first embodiment, corresponding to claim 3 of the present invention, the front jack 3A is grounded and the rear jack 3B is the stroke end of the vehicle body ground angle Δθ stored in the vehicle body ground angle storage means 42. Since the front wheel 12A is set at an angle larger than the distance away from the ground even when the front jack 3A is grounded, the front wheel 12A can be grounded even when the rear jack 3B is fully extended while the front jack 3A is grounded. No (Under all conditions during jack-up operation, it is possible to completely prevent the work vehicle from shifting to the escape state by the rear jack extension operation).

[Second Embodiment]
The jack operation control apparatus of the second embodiment shown in FIG. 4 employs a composite angle storage means 48 in place of the vehicle body inclination angle storage means 41 in the jack operation control apparatus of the first embodiment (FIG. 3).

  That is, the jack operation control device of the second embodiment of FIG. 4 includes a vehicle body inclination angle detecting means 15 (the same as that of the first embodiment), a vehicle body ground angle storage means 42 (the same as that of the first embodiment), The vehicle body inclination angle θ (see FIG. 5A) detected by the vehicle body inclination angle detection means 15 in the state where the front and rear wheels 12A and 12B are in contact with each other at the jack up execution place and the vehicle body ground angle storage means 42 The calculation means 43 for adding the stored vehicle body ground angle Δθ (see FIG. 5B) stored in the above, the combined angle storage means 48 for storing the combined angle X (θ + Δθ) added by the calculation means 43, and the above The comparison means 44 for comparing the current vehicle body inclination angle θ1 detected by the vehicle body inclination angle detection means 15 at the jack-up execution location with the stored composite angle stored in the composite angle storage means 48, and the ratio When the means 44 determines that the current vehicle body inclination angle θ1 is smaller than the stored composite angle X (θ1 <X), the extension operation of the rear jack 3B is prohibited, whereas the current vehicle body inclination angle is prohibited by the comparison means 44. When it is determined that the inclination angle θ1 is equal to or greater than the stored composite angle X (θ1 ≧ X), the rear jack extension control means 45 is configured to control so as to allow the extension operation of the rear jack 3B. .

  The jack operation control device of the second embodiment functions as follows.

  First, the stored vehicle body ground angle Δθ (see FIG. 5B) stored in the vehicle body ground angle storage unit 42 in the computing unit 43 and the two-wheel grounding when the front and rear wheels 12A, 12B are grounded at the jack-up implementation location. The vehicle body tilt angle θ (see FIG. 5A) is added, and the combined angle X (θ + Δθ) added by the calculation means 43 is stored in the combined angle storage means 48 in advance.

  Then, at the place where the jack up is performed, the comparison means 44 compares the current vehicle body inclination angle θ1 detected by the vehicle body inclination angle detection means 15 with the stored composite angle X stored in the composite angle storage means 48, and When the comparison means 44 determines that the current vehicle body inclination angle θ1 is smaller than the stored composite angle X (θ1 <X), a signal prohibiting the extension operation of the rear jack 3B from the rear jack extension control means 45 (rear jack extension prohibition) On the other hand, when the comparison means 44 determines that the current vehicle body inclination angle θ1 is equal to or greater than the stored composite angle X (θ1 ≧ X), the rear jack extension control means 45 extends the rear jack 3B. (A rear jack extension allowance signal 47) is issued.

  Also in the jack operation control apparatus of the second embodiment, the front jack 3A is grounded and the rear jack 3B is the stroke end corresponding to the third aspect of the present invention, the vehicle ground angle Δθ stored in the vehicle ground angle storage means 42. Even in the extended state, the angle is set to be equal to or larger than the angle at which the front wheel 12A is separated from the ground.

  Therefore, in the jack operation control apparatus of the second embodiment, the rear jack extension operation is performed under the condition that the front wheel 12A is grounded by extending the rear jack 3B as in the first embodiment. Since the rear jack 3B cannot be extended even if the operation is performed, even if the rear jack extension operation is performed by an operator's erroneous operation (for example, overlooking the grounding state of the front wheel 12A), the state shifts to a dangerous state where the work vehicle escapes. There is nothing (safety is ensured).

  1 is a vehicle, 2 is a work machine, 3A is a front jack, 3B is a rear jack, 4 is a controller, 11 is a vehicle body, 12A is a front wheel, 12B is a rear wheel, 15 is a vehicle body tilt angle detection means, and 31A and 31B are ground plates , 32A, 32B are ground contact detectors, 41 is a vehicle body inclination angle storage means, 42 is a vehicle body ground angle storage means, 43 is a calculation means, 44 is a comparison means, 45 is a rear jack extension control means, and 46 is a rear jack extension prohibition signal. , 47 are rear jack extension allowance signals, and 48 is a combined angle storage means.

Claims (3)

In a work vehicle having a parking brake that brakes the rear wheel, with front and rear, left and right wheels and front and rear, left and right jacks on the vehicle body,
Vehicle body tilt angle detection means for detecting the vehicle body tilt angle with respect to the front-rear horizontal direction;
Vehicle body inclination angle storage means for storing the vehicle body inclination angle when the front and rear wheels are in contact with each other, detected by the vehicle body inclination angle detection means in a state where the front and rear wheels are in contact with each other at a jack-up implementation location;
Vehicle body ground angle storage means for storing in advance the vehicle ground angle in a state where the rear wheel is grounded and the front wheel is separated from the ground;
Arithmetic means for adding the stored vehicle body inclination angle stored by the vehicle body inclination angle storage means and the storage vehicle body ground angle stored by the vehicle body ground angle storage means;
Comparison means for comparing the current vehicle body inclination angle detected by the vehicle body inclination angle detection means at the jack-up execution location with the combined angle added by the calculation means;
When the comparison means determines that the current vehicle body tilt angle is smaller than the combined angle, the rear jack is prohibited from extending, whereas the current vehicle body inclination angle is greater than or equal to the combined angle by the comparing means. And a rear jack extension control means for controlling so as to allow the extension operation of the rear jack.
A jack operation control device for a work vehicle. In a work vehicle having a parking brake that brakes the rear wheel, with front and rear, left and right wheels and front and rear, left and right jacks on the vehicle body,
Vehicle body tilt angle detection means for detecting the vehicle body tilt angle with respect to the front-rear horizontal direction;
Vehicle body ground angle storage means for storing in advance the vehicle ground angle in a state where the rear wheel is grounded and the front wheel is separated from the ground;
Arithmetic means for adding the vehicle body inclination angle detected by the vehicle body inclination angle detection means when the front and rear wheels are in contact with each other at the jackup execution place and the stored vehicle body ground angle stored in the vehicle body ground angle storage means; ,
Combined angle storage means for storing the combined angle added by the calculating means;
Comparison means for comparing the current vehicle body inclination angle detected by the vehicle body inclination angle detection means at the jack-up execution location with the stored composite angle stored in the composite angle storage means;
When the comparison means determines that the current vehicle body tilt angle is smaller than the stored composite angle, the rear jack is prohibited from extending, while the current vehicle body tilt angle is greater than the stored composite angle by the comparison device. A rear jack extension control means for controlling so as to allow the extension operation of the rear jack when it is determined that
A jack operation control device for a work vehicle. In claim 1 or 2,
The vehicle ground angle stored in the vehicle ground angle storage means is set to be equal to or greater than the angle at which the front wheel is separated from the ground even when the front jack is grounded and the rear jack extends to the stroke end.
A jack operation control device for a work vehicle.

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