JP2013237529A - Vehicle-mounted type crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle-mounted type crane capable of preventing compression breakage of a tilting cylinder for making the crane stable in the attitude even when only either one of outrigger cylinders is grounded first when the crane is installed before work.SOLUTION: This vehicle-mounted type crane is provided with one tilting cylinder 9 fitted as a tilting means for adjusting a tilting angle of a crane mounting platform, and holding state switching means 51 and 52 for releasing the holding of the tilting cylinder 9 in either direction of the compression side and the pull side of the tilting cylinder 9 only when an outrigger expansion and contraction operation signal is input and also an outrigger grounding signal 62 is input.

Description

  The present invention relates to a vehicle-mounted crane that can perform crane operations in a stable posture even on sloping ground.

  The vehicle-mounted crane is mounted on the chassis frame between the cab of the vehicle and the loading platform (that is, a position close to the front wheels), and the crane base is fixed on the chassis frame. When this type of vehicle-mounted crane is used on a sloping ground, the horizontal arm of the outrigger is usually extended to the left and right while the vehicle is parked laterally (contour direction) with respect to the tilt direction, and the left and right outrigger cylinders are Install the crane so that the base is horizontal while extending and contracting.

Then, since the chassis frame is also horizontal with the base of the crane, the front wheel or the rear wheel on the lower side of the slope (hereinafter referred to as “the valley side”) may be separated from the ground. Note that, in an inclined place where the inclination of the slope is not so large, even if the front wheel on the valley side is separated from the ground, the rear wheel on the valley side may remain in contact with the chassis frame in a twisted state.
On slopes, if both the front and rear wheels on the valley side move away from the ground, only the left and right outrigger cylinders and the front and rear wheels on the upper side of the slope (hereinafter referred to as “mountain side”) are in contact with the ground. The crane work on the side is less stable than the work on the horizontal ground, and the crane performance is reduced. In addition, even on slopes where the rear wheels of the valley side are not separated from the ground, when the chassis frame is twisted, the force to return the twist works, so in crane work on the valley side Compared with work on horizontal ground, the performance of the crane is reduced. In addition, in a state where the chassis frame is twisted, a burden is imposed on the vehicle itself, which causes a problem that durability of the vehicle is lowered.

  In order to deal with such problems, for example, in Patent Document 1, a support bracket fixed on a chassis frame between a cab of a vehicle and a loading platform, and a support shaft in the front-rear direction (crane rotation shaft) are mounted on the support bracket. ) Between the crane mounting base and the support bracket, and the crane mounting base that is pivotally supported so that it can be tilted right and left, the base that is mounted and fixed on the crane mounting base, and the crane mounting base and the support bracket. There is disclosed a technique for adjusting a tilt angle between a crane and a vehicle with a tilt cylinder that adjusts the angle.

  The technique described in this document includes a mechanism that releases a tilt angle and allows a crane to be freely tilted when a load of a predetermined value or more is applied to the tilt cylinder. Thereby, according to the technique described in the document, the tilting means itself can be prevented from being damaged, and the crane can be tilted freely with respect to the vehicle, so that twisting of the chassis frame due to a large load during operation can be suppressed.

  Further, in Patent Document 2, in a railway work vehicle having a crane on a work device mounting table on the vehicle side, a hydraulic cylinder serving as an axle lifting means is used to eliminate the inclination due to the deflection of the shaft spring of the work device mounting table. To raise the axle. Thereby, according to the technique described in the document, the crane can be operated in a stable posture without being affected by the deflection of the shaft spring.

JP 2002-370894 A (paragraph 0005) Japanese Patent Laid-Open No. 10-16730 (paragraphs 0006, 7, 9)

However, these technologies are intended to prevent the crane from receiving the force generated on the vehicle side during the crane operation, and the tilting cylinder (hydraulic cylinder (hydraulic pressure) by the reaction force received from the outrigger during the crane installation before the operation). Cylinder) is not made against damage.
In other words, even if two outrigger cylinders are simultaneously extended in an outrigger equipped on a vehicle-mounted crane, both the left and right outriggers are operated at the same time due to pressure loss due to the structure of the device, etc. It is difficult to tune and stretch at speed. Therefore, only one of the outrigger cylinders contacts the ground first, and the vehicle is lifted only by the one outrigger cylinder. In this case, when the moment force consisting of the reaction force received from the ground by the outrigger cylinder that has been grounded earlier and the distance between the point of action of the reaction force and the center of the crane rotation axis directly applies the force in the compression direction of the tilt cylinder As a result, the tilting cylinder may be compressed and broken.

  Therefore, the present invention has been made paying attention to such problems, and even when only one of the outrigger cylinders is grounded first when installing the crane before work, It is an object of the present invention to provide a vehicle-mounted crane that can prevent compression fracture of a tilting cylinder for achieving a stable posture.

  In order to solve the above-described problem, a vehicle-mounted crane according to an aspect of the present invention includes a support bracket fixed on a chassis frame between a cab of a vehicle and a loading platform, and the support bracket includes a front-rear direction. Outrigger grounding detection for detecting grounding between a crane mounting base that is pivotally supported by a support shaft and a base having a pair of outriggers mounted and fixed on the crane mounting base and the ground when the outrigger is installed And a tilting cylinder mounted as a tilting means for adjusting the tilting angle of the crane mounting base with respect to the vehicle between the crane mounting base and the support bracket, and a telescopic operation signal of the outrigger Holding state switching means for releasing the holding of the tilting cylinder by inputting both of the grounding signal from the outrigger grounding detection means. And said that there were pictures.

Here, in the vehicle-mounted crane according to one aspect of the present invention, the holding state switching unit is provided in a hydraulic circuit for driving the tilting cylinder to extend and contract so as to hold the expanding and contracting state of the tilting cylinder. When the outrigger expansion / contraction operation signal is input between the double pilot check valve and the tilt cylinder and the double pilot check valve to prevent compression failure of the tilt cylinder, and the ground signal of the outrigger Only when the signal is input, an electromagnetic switching valve that forms a communication circuit with the tank is provided on both the compression side and the tension side of the tilt cylinder so that the hydraulic oil of the tilt cylinder is released to the tank.

  According to the present invention, the holding state switching means for holding and releasing the tilt cylinder is when the outrigger is being expanded and contracted, and when both signals of the ground signal when the outrigger is grounded are input, Since the holding is released in both the compression side and the tension side, even when only one of the outrigger cylinders is grounded first when installing the crane before work, the crane is in a stable posture. Therefore, the compression failure of the tilting cylinder can be prevented.

1 is a plan view illustrating an embodiment of a vehicle equipped with a vehicle-mounted crane according to an aspect of the present invention. It is a side view of FIG. It is the rear view seen from the back (loading side) of Drawing 1, and the figure shows the state where vehicles were located on slope GL. FIG. 3 is a circuit diagram illustrating an embodiment of a configuration of a tilt cylinder, a holding state switching unit that holds and releases the tilt cylinder, and a lever operation detection unit in a vehicle-mounted crane according to an aspect of the present invention. It is a figure explaining the example which the outrigger cylinder by the side of a valley grounded previously from the state shown in FIG. It is a figure explaining the state which the right and left outrigger cylinders earth | grounded from the state shown in FIG. It is a figure explaining the example which the outrigger cylinder of the mountain side grounded previously from the state shown in FIG. It is a figure which expands and shows the part of the tilting cylinder shown in FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings as appropriate.
As shown in FIGS. 1 and 2, in this vehicle-mounted crane 1, a base 3 having an outrigger 2 is mounted and fixed on a crane mounting base 6. The outrigger 2 includes horizontal arms 21 and 22 that can be expanded and contracted in the left-right width direction of the vehicle 10, and outrigger cylinders (vertical outriggers) 23 and 24 that are fixed to the ends of the horizontal arms 21 and 22 and can be expanded and contracted in the vertical direction. ing. Floats 25 and 26 serving as ground members are attached to lower ends of the outrigger cylinders 23 and 24, respectively. The outrigger cylinders 23 and 24 can be operated in synchronism with either the left or right outrigger operation lever 31. A pivotable column 4 is provided on the base 3, and a telescopic boom 5 is pivotally supported at the upper end of the column 4 so as to be raised and lowered. A support bracket 7 that supports the crane mounting base 6 is fixed on the chassis frame 13 between the cab 11 and the loading platform 12 of the vehicle 10.

  As shown in FIG. 3, ground detection switches 62 are provided between the left and right horizontal arms 21 and 22 at the left and right ends of the inner upper portion of the base 3. Between the base 3 and the horizontal arm 21, there is a fitting gap on the fitting for the horizontal arm 21 to slide. The grounding detection switch 62 is provided so as to detect a change in the fitting gap. It has been. The ground detection switch 62 is outrigger ground detection means for detecting the grounding of each outrigger cylinder 23, 24 when each outrigger cylinder 23, 24 lifts the vehicle 10. That is, when the floats 25, 26 of the outrigger cylinders 23, 24 are grounded, the horizontal arms 21, 22 are raised inside the base 3. At this time, when the fitting gap is reduced between the upper portions of the base 3, the ground detection switch 62 is turned “ON” and the ground signal of the outrigger 2 is output. As the ground detection switch 62, for example, a proximity switch or a limit switch can be suitably used.

  As shown in FIG. 3, the crane mounting base 6 is pivotally supported on the support bracket 7 by a crane rotation shaft 8 that is a support shaft that faces in the front-rear direction. Further, between the crane mount 6 and the support bracket 7, one tilt cylinder (cant correction cylinder) 9 is used as tilting means for adjusting the tilt angle (cant angle) α of the crane mount 6 with respect to the vehicle 10. Is installed.

FIG. 4 is a circuit diagram for explaining an embodiment of the configuration of the tilt cylinder 9, the holding state switching means for holding and releasing the tilt angle α by the tilt cylinder 9, and the controller (control device).
As shown in the figure, the vehicle-mounted crane 1 includes the above-described grounding detection switch 62 that is an outrigger grounding detection unit and a differential transformer 53 that is a lever operation detection unit of the outrigger operation lever 31 of the crane 1. I have. The outrigger expansion / contraction operation signal by the differential transformer 53 is input to the controller 60. Further, the hydraulic circuit for extending and retracting the tilting cylinder 9 includes a double pilot check valve 51 for holding pressure oil in the extending and contracting direction of the tilting cylinder 9 and is connected between the oil passages of the tilting cylinder 9 and the double pilot check valve 51. The electromagnetic switching valve 52 is provided.

  Although the lever operation detecting means of the present invention will be described below using a differential transformer, the operation of the outrigger operation lever may be detected by a limit switch or the like, for example, instead of the differential transformer. In this case, if a limit switch or the like is incorporated in the relay power supply circuit described below, it can be used without inputting an outrigger expansion / contraction operation signal to the controller.

The electromagnetic switching valve 52 is connected in series to a relay that is excited when the ground detection switch 62 is closed and a relay that is excited by a lever operation signal output from the controller 60 when one of the outrigger operation levers 31 is operated. ing.
The electromagnetic switching valve 52 is configured to be supplied with power via the respective relays when the ground detection switch 62 is closed and when any of the outrigger operating levers 31 is operated.

  A tilt cylinder operating mechanism 34 is provided between the double pilot check valve 51 and the pump 32, and the tilt cylinder 9 can be expanded and contracted by switching the oil passage in the mechanism by operating the lever of the tilt cylinder operating mechanism 34. When the lever operation is stopped, the double pilot check valve 51 is configured to be in a “block state” in which the tilt cylinder 9 is held in both the compression side and the tension side.

When the left or right lever operation is detected (condition 1) and the outrigger grounding condition (condition 2) is not satisfied at the same time, the electromagnetic switching valve 52 causes the oil passage to be blocked by the internal spool of the electromagnetic switching valve 52. The pressure oil in the tilting cylinder 9 is prevented from flowing into the tank 30.
On the other hand, when the operation signal is output, the electromagnetic switching valve 52 is provided so as to communicate between the tilting cylinder 9 and the tank 30. As a result, the tilt cylinder 9 reduces the pressure in the tilt cylinder 9 only when the outrigger expansion / contraction operation signal is input (condition 1) and only when the outrigger grounding signal is input (condition 2). In both the compression side and the tension side of the pulling cylinder 9, the holding of the tilting cylinder 9 is released, and the crane mount 6 is allowed to tilt freely. Therefore, it is possible to prevent the tilting cylinder 9 from being damaged due to overload. Note that the conditions 1 and 2 may be satisfied when either the left or right operation lever 31 or the left or right grounding detection switch 62 is activated.

Next, operation examples and effects of the vehicle-mounted crane 1 will be described with reference to FIGS. 3 and 5 to 8 as appropriate. In this example, the work procedure from the crane retracted state to the crane working state (when the vehicle is used on an inclined ground GK) will be described.
In order to shift from the crane retracted state to the crane working state, as shown in FIG. 3, first, the left and right horizontal arms 21 and 22 are pulled out in the lateral direction of the vehicle, and then the tilt cylinder 9 is moved by the tilt cylinder operating mechanism 34. Operate and adjust the posture of the crane mount 6 so that the crane 1 is level with the ground. When the operation of the tilt cylinder operating mechanism 34 is stopped, the tilt cylinder 9 is in a “block state” at that position. However, it is extremely difficult to adjust the posture of the crane mount 6 so that the crane 1 is completely horizontal. Therefore, in the figure, it is assumed that the crane 1 is inclined to the valley side and the center of gravity is also biased to the valley side.

First, an example in which the outrigger cylinder 23 on the passenger seat side (valley side) first contacts the state shown in FIG. 3 will be described with reference to FIG.
In order to extend the left and right outrigger cylinders 23 and 24 from the state shown in FIG. 3, the operator switches the outrigger operation lever 31 to the extension operation, and simultaneously operates the two outrigger cylinders 23 and 24.

  Next, when the differential transformer 53 responds to the extending operation of the outrigger operation lever 31, an operation signal is transmitted to the controller 60. In response to the input of the operation signal, a lever operation signal is output to the relay side and the relay is excited, but the ground detection switch 62 is “OFF”, so that the solenoid of the electromagnetic switching valve 52 itself is not energized yet. Therefore, the two outrigger cylinders 23 and 24 extend while the tilting cylinder 9 is maintained in the “block state”.

Here, even if the two outrigger cylinders 23 and 24 are simultaneously extended due to pressure loss due to the structure of the apparatus, it is difficult to synchronize and extend the cylinders at exactly the same speed. Therefore, in this example, it is assumed that the valley-side outrigger 23 is first grounded to the ground GL.
The grounding state at this time is such that the float 25 at the tip of the outrigger cylinder 23 touches the ground GL (at this time, the grounding detection switch 62 is “OFF”). When the outrigger cylinder 23 is further extended after the float 25 contacts the ground GL, the horizontal arm 21 rises inside the base 3 and the fitting gap is reduced between the upper parts of the base 3. Becomes “ON”. Therefore, in addition to the state in which the outrigger extension operation signal is input from the differential transformer 53 (condition 1), both the relays are excited by the outrigger ground signal (condition 2) when the ground detection switch 62 is “ON”. The electric circuit becomes a closed circuit.

As a result, the solenoid of the electromagnetic switching valve 52 is energized, the internal spool is switched, and the oil passage of the tilting cylinder 9 is connected to the tank 30 side. Therefore, the tilting cylinder 9 enters a “free state” in which the holding of the tilting angle α is released in both the compression side and the tensioning side of the tilting cylinder 9.
Although the tilting cylinder 9 is in the “free state”, since the center of gravity of the crane has been biased toward the valley side from the start of work, the grounding detection switch 62 remains in the “ON” state and the fit between the base 3 and the horizontal arm 21 is The crane 1 instantaneously tilts to the valley side by the backlash due to the gap. However, since the fitting gap is very small, the crane 1 does not tilt greatly. The tilt cylinder 9 also remains in the “free state”.

  Here, if the tilt cylinder 9 remains in the “blocked state”, the vehicle tries to lift the vehicle only by the one-side outrigger cylinder 23 previously grounded, so the reaction force that the grounded outrigger cylinder 23 receives from the ground first. The moment force F ′ (= F1), which is composed of F and the point of action of the reaction force F and the center distance l of the crane rotation shaft 8, transmits the force in the compression direction of the tilt cylinder 9 as it is. 9 may be compressed and broken. On the other hand, according to this crane 1, since the tilting cylinder 9 is set in the “free state”, it is possible to prevent the tilting cylinder 9 from being compressed and broken.

  Thereafter, as shown in FIG. 6, the float 26 at the tip of the mountain-side outrigger cylinder 24 is also grounded, and the crane 1 is installed in a correct work start state. Next, when the operator returns the outrigger operation lever 31 to neutral, the extension operation signal from the differential transformer 53 to the controller 60 is interrupted. Thereby, when the output of the operation signal from the controller 60 to the electromagnetic switching valve 52 is stopped, the tilting cylinder 9 is switched again to the “block state”, so that the crane work can be started in a stable posture.

Next, an example in which the outrigger cylinder 24 on the driver's seat side (mountain side) contacts the ground first after the state shown in FIG. 3 will be described with reference to FIG.
Similarly to the above, the operator first switches both the outrigger operation levers 31 to the extension operation, and simultaneously operates the two outrigger cylinders 23 and 24. By this extension operation, an extension operation signal from the differential transformer 53 is transmitted to the controller 60. At this time, the electromagnetic switching valve 52 remains unenergized. Therefore, the tilt cylinder 9 is maintained in the “block state”.

Next, the ground 26 is grounded to such an extent that the float 26 of the mountain-side outrigger cylinder 24 touches the ground GL first, but the grounding detection switch 62 remains “OFF”. When the outrigger cylinder 24 further extends, the horizontal arm 22 rises inside the base 3 and the ground detection switch 62 is turned “ON”.
Therefore, an outrigger extension operation signal is input from the differential transformer 53 to the controller 60 (condition 1), and an outrigger ground signal (condition 2) when the ground detection switch 62 is “ON” is input to the controller 60. As a result, the solenoid of the electromagnetic switching valve 52 is energized, and the internal spool is switched. As a result, the oil passage of the tilting cylinder 9 communicates with the tank 30 side, and the tilting cylinder 9 enters a “free state” in which the holding is released.

  Here, due to the deviation of the center of gravity of the crane toward the valley side, the crane 1 instantaneously tilts toward the valley side by a backlash of a slight fitting clearance on the structure between the base 3 and the horizontal arm 22. At this time, due to the tilt of the crane 1, the ground detection switch 62 that was in the “ON” state on the driver's seat side is switched to “OFF” for a short time. Accordingly, the energization to the solenoid of the electromagnetic switching valve 52 is interrupted, so that the oil passage communicating with the tank 30 is also interrupted, and the tilting cylinder 9 is instantaneously put into the “block state”. Therefore, the crane 1 does not tilt any further. As shown in the enlarged view of the tilt cylinder 9 in FIG. 8, in this example, when the tilt cylinder 9 extends, the crane 1 tilts toward the driver's seat, and when the tilt cylinder 9 contracts, the crane 1 moves toward the passenger seat. Will tilt.

Next, as shown in FIG. 6, the float 25 of the valley-side outrigger cylinder 23 is grounded, and the ground detection switch 62 is turned “ON” again. The crane 1 is correctly installed until the work start state.
Next, when the operator returns the outrigger operation lever 31 to the neutral position, the extension operation signal from the differential transformer 53 to the controller 60 is interrupted. Thereby, when the output of the operation signal from the controller 60 to the electromagnetic switching valve 52 is stopped, the energization to the solenoid of the electromagnetic switching valve 52 is cut off, so that the tilt cylinder 9 is switched again to the “block state”. Crane work can be started with a stable posture. The contents of the above operation are shown in Table 1.

As described above, according to the vehicle-mounted crane 1, the energization conditions of the electromagnetic switching valve 52 are the expansion / contraction operation signal from the differential transformer 53 (the outrigger operation lever 31 is in the operation state: condition 1), and the base 3. When the solenoid of the electromagnetic switching valve 52 is energized by both signals of the grounding signal from the grounding detection switch 62 (outrigger is grounded: Condition 2) provided in The “free state” is established in which the tilting cylinder 9 is released from the operation by being released to 30. Thereby, the reaction force of the outrigger can be released by rotating the crane rotation shaft 8. Therefore, even when only one of the outrigger cylinders is grounded first when the crane is installed before work, it is possible to prevent the compression cylinder 9 from being compressed and broken to make the crane 1 stable. .
Note that the vehicle-mounted crane according to the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Crane 2 Outrigger 3 Base 4 Column 5 Boom 6 Crane mount 7 Support bracket 8 Support axis (crane rotation axis)
DESCRIPTION OF SYMBOLS 9 Tilt cylinder 10 Vehicle 11 Driver's cab 12 Car bed 13 Chassis frame 14 Rear wheel 21, 22 Horizontal arm 23, 24 Outrigger cylinder 25, 26 Float 31 Outrigger operation lever 32 Pump 34 Tilt cylinder operation mechanism 51 Double pilot check valve (holding state switching) means)
52 Electromagnetic switching valve (holding state switching means)
53 Differential transformer 60 Controller 62 Ground detection switch

Claims (2)

  A support bracket fixed on a chassis frame between a cab of the vehicle and a loading platform; a crane mounting base pivotally supported by the support bracket so as to be tiltable to the left and right by a support shaft in the front-rear direction; and the crane mounting base A base having a pair of outriggers mounted and fixed to the ground, outrigger grounding detecting means for detecting grounding with the ground when the outriggers are installed, and the crane mounting base for the vehicle between the crane mounting base and the support bracket A tilt cylinder mounted as a tilting means for adjusting the tilt angle, and holding the tilt cylinder by inputting both the outrigger expansion / contraction operation signal and the grounding signal from the outrigger grounding detection means A vehicle-mounted crane comprising state switching means.   The holding state switching means is provided in a hydraulic circuit for driving the tilting cylinder to extend and contract, and includes a double pilot check valve for holding the expanding and contracting state of the tilting cylinder, the tilting cylinder, and the double pilot check valve; Only when the outrigger expansion / contraction operation signal is input and when the outrigger grounding signal is input, the compression of the tilt cylinder is released so that the pressure oil in the tilt cylinder is released to the tank. The vehicle-mounted crane according to claim 1, further comprising an electromagnetic switching valve that forms a communication circuit with the tank on both the side and the tension side.

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