JPS6147734B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a vehicle body frame in which hydraulic jacks for stabilizing the vehicle body that can be extended to both sides are attached to the intermediate and rear ends of the vehicle body frame in the longitudinal direction, respectively, and a swing crane is mounted between the two hydraulic jacks. The present invention relates to a control device for a hydraulic jack for stabilizing a vehicle body in a vehicle equipped with a swing crane, in which the bending strength near the front end of the vehicle body frame is weaker than that of the front end of the vehicle body frame.

Conventionally, in such a crane vehicle, when the boom is swung toward the front of the vehicle to perform so-called front-lifting cargo handling work, when the center of gravity of the entire crane vehicle moves forward from the intermediate hydraulic jacks on both sides, the lower end of the intermediate hydraulic jacks The body frame tilts forward using the front wheel as a fulcrum, and the grounding point of the front wheel causes the front wheel and its suspension spring to bend. However, if the suspension spring is fully deflected due to the forward tilt of the body frame, the entire crane truck The center of gravity moves significantly forward, significantly increasing the load on the front axle.
The body frame is twisted or bent. However, by installing a hydraulic jack on the front end of the car body frame,
If this initial forward tilting movement of the body frame is prevented, only a relatively small supporting force is given to the front end of the body frame by the front end hydraulic jack, and even when the front suspension is suspended, it is equivalent to side suspension or rear suspension. Allowable lifting load can be set. However, on the other hand, if the front end hydraulic jack lifts the car body before the intermediate hydraulic jack lifts the car body when the full hydraulic jack is extended, or if the intermediate hydraulic jack contracts before the front end hydraulic jack when the full hydraulic jack is contracted, Since the front and rear ends of the vehicle body frame are supported by the front end hydraulic jack and the rear end hydraulic jack or the rear wheels,
Depending on the swinging position and angle of the boom and the length of the boom, there is a risk that the body frame may be twisted or bent.

The present invention deals with this problem. When lifting a vehicle body with a full hydraulic jack, at least the intermediate hydraulic jack and the front end hydraulic jack are activated to extend at the same time, and when reducing the full hydraulic jack, the front end hydraulic jack is activated simultaneously. An automatic control device is provided in which the intermediate hydraulic jack is reduced after the hydraulic jack is reduced.

Embodiments of the present invention will be described below with reference to the drawings. In the case of FIGS. 1 to 4, the operating cylinder 3 of the front end hydraulic jack 1 attached to the front end of the vehicle body frame 13
and the operating cylinder 4 of the intermediate hydraulic jack 6 are connected in parallel to one directional control valve 5, and a signal generating device 7 is installed on the intermediate hydraulic jack 6 side to generate a signal when it is extended. A valve 8 that opens only when the front end hydraulic jack is received is inserted into the high pressure side oil passage 9 between the operating cylinder 3 of the front end hydraulic jack and the directional control valve 5 when the front end hydraulic jack is extended, and after the front end hydraulic jack is contracted. A sequence valve 11 that opens as the working oil pressure increases and a check valve 11' that allows oil to return to the tank 39 are connected between the operating cylinder 4 of the intermediate hydraulic jack and the directional control valve 5 when the intermediate hydraulic jack is reduced. are inserted in parallel into the high pressure side oil passage 12 of.

The bending strength of the portion of the body frame 13 approximately rearward of the front wheels 14 is significantly greater than the bending strength of the portion ahead of the front wheels, and the intermediate hydraulic jack 6 and the rear end hydraulic jack 16 are connected to this portion of the body frame having high bending strength. A swivel base 18 is mounted on both sides of the vehicle body frame 13 between the two hydraulic jacks 6 and 16 so as to be extendable and retractable. Reference numeral 19 indicates an automobile driver's cab attached to one side of the upper part of the front end of the vehicle body frame 13, and 20 indicates a rear wheel.

The intermediate hydraulic jacks 6 on both sides are supported at the tips of telescopic power telescopic beams 21 installed in parallel on the lower surface of the vehicle body frame so as to be able to extend horizontally to the left and right sides of the vehicle body, respectively. The leg tube 2 is slidably inserted into the guide tube 22 fixed perpendicularly to the tip of the power telescopic beam 21, and the lower end of the leg tube 2 is fixed to the lower part of the piston rod 23 of the double-acting actuating cylinder 4, The upper end of the operating cylinder is attached to the upper end of the guide tube 22 by a pin 24, and a ground plate 25 is attached to the lower end of the piston rod 23 so as to be freely tiltable. Stoppers 4' and 4'' (fourth
(Fig.) are provided respectively.

The rear end hydraulic jacks 16 on both sides are supported by the vehicle body frame 13 via telescopic power telescoping beams similarly to the intermediate hydraulic jack 6, and have exactly the same configuration as the intermediate hydraulic jack 6.

The front end hydraulic jack 1 has exactly the same structure as the intermediate hydraulic jack 6, and its guide tube 26 (Fig. 1)
is fixed vertically to the center of the front end of the vehicle body frame 13, and is expanded and contracted by a double-acting actuating cylinder 3 (FIG. 4). The operating cylinder 3 is also provided with stoppers 3' and 3'' (Fig. 4) facing the piston and regulating the extension and contraction limits of the front end hydraulic jack 1, respectively, and is controlled by the intermediate and rear end hydraulic jacks 6 and 16. Even if the front end hydraulic jack 1 is extended to the maximum when lifting the vehicle body, a very small gap is created between the lower end and the ground. A high hydraulic pressure is generated to open the valve 11. Reference numeral 3 indicates a piston rod, and 33 indicates a pilot oil passage of the sequence valve 11 connected to the oil passage 10.

The signal generator 7 is constructed by fitting both ends of a pin 24 attached to the upper end of each actuating cylinder 4 into a vertical elongated hole 27 bored in the guide tube 22, respectively, to connect the ground plate 25 as shown in FIG. The pin 24 is engaged with the upper ends of the elongated holes 27, 27 on both sides by the extension of the actuating cylinder 4 after it touches the ground, and at this time, the top surface of the actuating cylinder 4 is attached to the upper end of the guide tube 22 opposite to this. The limit switch 28 is closed, and the limit switches 28, 2 of the guide cylinders 22, 22 on both sides are closed.
8 are inserted in series into the control circuit 29 of the solenoid valve 8. In the figure, 30 is a compression spring held between the top surface of the operating cylinder 4 and the bottom surface of the top plate of the guide tube 22;
Reference numerals 1 and 32 indicate a switch and a battery inserted into the control circuit 29, respectively.

The solenoid valve 8 inserted into the oil passage 9 is in the cutoff position shown in FIG. 4 due to its own return spring when it is not conductive, and the signal current when both limit switches 28, 28 are closed causes the solenoid valve 8 to close as shown in the upper part of FIG. Switched to open position. 34 is a pilot check valve inserted into the oil passage 9; 35 is a pilot oil passage that transmits the pilot oil pressure of the oil passage 10 to the pilot check valve 34; the set pressure of the pilot check valve 34 is the same as the setting of the sequence valve 11; significantly lower than pressure. Both side operating cylinders 4, 4 have oil passages 12, 36
The pilot check valves 37 connected in parallel between the cylinders 4 and 4 and inserted into the high pressure side oil passages 36 when the cylinders are extended correspond to the respective operating cylinders 4, 4, respectively, and are connected to the oil passages 12 through pilot oil passages 38'. Controlled by pilot hydraulic pressure.

The three-position directional control valve 5 selectively connects the oil passages 10 , 12 and the oil passages 9 , 36 to the discharge port of the hydraulic pump 38 , and simultaneously communicates the other oil passage with the tank 39 .

Next, the operation of the present invention will be explained. From the state where the vehicle body frame 13 is supported on the ground G via the front and rear wheels 14, 20, the oil passages 9, 36 are connected to a hydraulic power source by the directional control valve 5 in order to carry out cargo handling work,
Even if the rear end hydraulic jack 16 is extended at the same time, the operating cylinders 4 on both sides are still contracted, and the pin 24 is pushed into the elongated holes 27 on both sides by the weight of the operating cylinders and the leg cylinder 2, etc., and the elasticity of the spring 30. 27
engages the lower end of the limit switch 28,
Since 28 is open, the solenoid valve 8 is in the shutoff position shown in FIG. Therefore, the pressure oil opens the pilot check valve 37 in the oil line 36 and enters the high pressure chamber when each working cylinder 4 is extended, while the low pressure chamber of the hydraulic cylinder is connected to the tank 39 via the oil line 12 and the check valve 11'. Therefore, after the two operating cylinders 4, 4 are extended and the ground plates 25 on both sides are brought into contact with the ground, the pins 24 are engaged with the upper ends of the long holes 27, 27 on both sides, as shown in FIG. Close limit switches 28, 28.

Therefore, the circuit 29 becomes conductive and the valve 8 is switched to the upper open position in FIG.
Operating cylinder 3 via pilot check valve 34
It enters the high pressure chamber during extension, while the low pressure chamber of the working cylinder is connected to the tank 39 via the oil line 10. In this state, the intermediate and rear end hydraulic jacks 6 and 16 are under the weight load of the vehicle equipped with the swing crane, while the front end hydraulic jack 1 is under no load, so pressure oil only flows into the working cylinder 3. After the front end hydraulic jack is extended and touches the ground, the vehicle body is further pushed up.

Therefore, all the hydraulic jacks 1, 6, and 16 lift and force the vehicle body with gradually increasing hydraulic pressure, so there is no fear that the vehicle body frame is supported at both ends by the hydraulic jacks at the front and rear ends, and the vehicle is equipped with a swing crane. Since the weight of the front end suppresses the extension of the front end hydraulic jack, there is no risk that the front end of the vehicle body frame, which has weak bending strength, will twist or bend.
When the vehicle equipped with the swing crane is lifted up as shown in FIG. 1, the vehicle body is supported by the intermediate and rear end hydraulic jacks 6, 16, and a small gap is formed between the front end hydraulic jack 1 and the ground. Therefore, no load is applied to the front end hydraulic jack.

Intermediate hydraulic jack 6 and rear end hydraulic jack 1
6 is extended at the same time, but the rear end hydraulic jack 16 is extended before the intermediate hydraulic jack 6.
When the front end of the body frame 13 is extended, the front part of the body frame 13 is supported on the ground via the front wheel 14, and when the intermediate hydraulic jack is extended before the rear end hydraulic jack is extended, the rear part of the body frame 13 is supported by the rear wheel. 20, there is no problem even if the rear end hydraulic jack extends before or after the intermediate hydraulic jack.

When the telescopic boom 17 is swiveled to the front of the vehicle and hung at the front as shown in FIG. 1, the supporting force of the front end of the vehicle body frame 13 by the operating cylinder 3 when the vehicle body frame 13 is tilted forward using the intermediate hydraulic jack 6 as a fulcrum is as follows. As described above, since it can be made small, it is preferable to make the pressure receiving area of the high pressure chamber small when the actuating cylinder 3 is extended.

From this state, in order to reduce the hydraulic jacks 1 and 6 and ground the front and rear wheels, the directional control valve 5 connects the oil passages 10 and 12 to the hydraulic power source, but the limit switches 28 and 28 are still closed and the valve 8 is in the open position. , and the hydraulic pressure required to contract the operating cylinder 3 is low, so the sequence valve 11 is in a cutoff state,
Since the check valve 11' cannot be opened, pressure oil enters the high pressure chamber from the oil passage 10 when the working cylinder 3 is contracted, and on the other hand, the pilot check valve 34 opens due to the oil pressure in the oil passage 10, and the low pressure chamber of the working cylinder is connected to the tank via the oil passage 9, so the working cylinder 3 or the front end hydraulic jack 1 is reduced in size.

When the working cylinder 3 is completely contracted and the oil pressure in the oil passage 10 rises, and the oil pressure reaches the set pressure of the sequence valve 11 or higher, the sequence valve opens and the oil passage 12 is opened.
Pressure oil is supplied to Therefore, pressure oil enters the high pressure chamber when the working cylinders 4, 4 are contracted, and on the other hand, the oil pressure in the oil passage 12 causes the pilot check valve 37 to
is opened and the low pressure chamber of the working cylinder is connected to the tank via the oil passage 36, so that the working cylinders 4, 4
begins to shrink, and when each of the ground planes 25 is separated from the ground, the pin 24 moves into the operating cylinder 4.
Due to their own weight, the limit switches 28, 28 are engaged with the lower ends of the elongated holes 27, 27 on both sides, and the limit switches 28, 28 are opened, switching the solenoid valve 8 to the cutoff position. In this way, each working cylinder 4 or intermediate hydraulic jack is retracted and lifted off the ground. Therefore, in this case as well, the vehicle body frame is supported at both ends by the front end and rear end hydraulic jacks while each hydraulic jack is being contracted, and there is no fear that the vicinity of the front end portion of the vehicle body frame, which has a weak bending strength, will be damaged. Even if the hydraulic jacks 1 and 6 are retracted before or after the rear end hydraulic jack 16 is retracted, there is no interference because either the front or rear wheels touch the ground and support the vehicle body, as in the case described above.

Although one embodiment has been described above, instead of closing the limit switch 28 after the ground plate 25 touches the ground due to the extension of the actuating cylinder 4, the limit switch 28 closes after the actuating cylinder 4 has expanded to a certain extent before the ground plate touches the ground. 28 may be closed, and a throttle valve may be appropriately inserted in the middle of the oil passage 9, so that the front end hydraulic jack 1 is extended after the intermediate hydraulic jack 6 is extended.
The same effect can also be obtained by attaching the grounding plate 25 to the piston rod 23 so that it can move up and down slightly, and installing the limit switch 28 between the piston rod and the grounding plate.

In the case of Figures 2 to 4, the intermediate hydraulic jack 6
A signal generating device 7 is installed on the side to generate a signal when the signal generating device is extended, and a valve 8 that is opened by the signal from the signal generating device is inserted into the high pressure side oil passage 9 when the front end hydraulic jack side operating cylinder is extended. Regardless of the magnitude of the frictional resistance of each part of each hydraulic jack, the front end hydraulic jack always extends reliably after the intermediate hydraulic jack extends. However, as mentioned above, the force that prevents the initial forward tilting movement of the vehicle body frame during forward suspension, that is, the load on the front end hydraulic jack 1, may be small, so the pressure receiving area of the high pressure chamber when the operating cylinder 3 is extended is It can be made smaller than the pressure receiving area of the high pressure chamber during expansion.

Therefore, instead of providing the signal generator 7 and the valve 8,
A similar function is provided by making the pressure receiving area of the front end hydraulic jack side operating cylinder 3 smaller than the pressure receiving area of the intermediate hydraulic jack side operating cylinder 4 so that the front end hydraulic jack 1 extends after the intermediate hydraulic jack 6 extends. obtain. In this case, since both actuating cylinders 3 and 4 are urged to extend at the same time, pressure is applied to the actuating cylinder 3 in order to prevent the vicinity of the front end of the vehicle body frame, which has weak bending strength, from deforming due to the elongating force of the front end hydraulic jack. It is obvious to reduce the area.

FIG. 5 shows this embodiment, in which a sequence valve 11 that opens due to an increase in the working pressure of the front end hydraulic jack 1 after contraction, and a check valve 11' that allows oil to return to the tank are connected to an intermediate hydraulic jack 6. Inserting the intermediate hydraulic jack in parallel with the directional control valve 5 into the high-pressure side oil passage during contraction is as follows:
This is the same as the case in FIG. In FIG. 5, members with the same reference numerals as those in FIG. 4 indicate corresponding members.

In this case, if the oil passages 9 and 36 are connected to the hydraulic power source from the hydraulic jack contracted state shown in FIG. Since the extension force 3 cannot bend or twist the vicinity of the front end of the vehicle body frame, when the operating cylinder 4 or the intermediate hydraulic jack 6 extends and lifts the vehicle body,
Following this, the operating cylinder 3 or the front end hydraulic jack 1 extends until it supports the front end of the vehicle body frame.

Also, from the extended state of each hydraulic jack 3, 4, the oil passage 1
0 is connected to a hydraulic pressure source, the working cylinder 3 contracts, and after the contraction is completed, the sequence valve 11 opens due to the increase in the working hydraulic pressure, and the working cylinder 4 also contracts in the same way.

According to the present invention, when the full hydraulic jack is extended from the running state of the car, the front end hydraulic pressure is Since the jack is configured to extend, there is no possibility that the extension of the intermediate hydraulic jack will be delayed when the full hydraulic jack is extended, resulting in the vehicle body being supported at both ends by the hydraulic jacks at the front and rear ends, and the front end of the vehicle body frame can be bent. If it is possible to prevent twisting or twisting, and if the full hydraulic jack can be retracted from the lifted state of the vehicle, use the high pressure oil generated after the front end hydraulic jack has been reduced by the action of the sequence valve to reduce the intermediate hydraulic jack. Because of this structure, not only can the intermediate hydraulic jack, which is under a large load, be retracted smoothly, but also the reduction of the intermediate hydraulic jack precedes the reduction of the entire hydraulic jack, and the front end and rear end hydraulic jacks are reduced. A control device for a hydraulic jack for vehicle body stabilization in a vehicle equipped with a swing crane and having a front end portion of the body frame with low bending strength, which is capable of preventing bending or twisting of the front end portion of the body frame without causing a state in which both ends of the vehicle body frame are supported. It is highly effective.

[Brief explanation of the drawing]

Fig. 1 is a side view of a vehicle equipped with a swing crane equipped with a device of the present invention, Fig. 2 is a vertical sectional side view of an intermediate hydraulic jack, Fig. 3 is a front view thereof, and Fig. 4 is a hydraulic and electric circuit according to one aspect of the present invention. FIG. 5 is a hydraulic circuit diagram in another embodiment of the present invention. 1... Front end hydraulic jack, 3, 4... Operating cylinder, 3''... Stopper, 5... Directional control valve,
6...Intermediate hydraulic jack, 7...Signal generator,
8... Solenoid valve, 9, 10... Oil path, 11... Sequence valve, 11'... Check valve, 12... Oil path, 13... Vehicle body frame, 16... Rear end hydraulic jack, 17... Telescopic boom, 18...swivel base,
28...limit switch, 36...oil line.

Claims (1)

[Scope of Claims] 1 Hydraulic jacks for stabilizing the car body that can be extended to both sides are attached to the middle and rear end of the car body frame in the longitudinal direction, and the parts of the car body frame between the two hydraulic jacks on which a swing crane is mounted are compared. In a vehicle equipped with a swing crane in which the bending strength near the front end of the body frame is weakened, a front end hydraulic jack is also attached to the front end of the body frame, and the operating cylinders of the front end hydraulic jack and the intermediate hydraulic jack are controlled in one direction. connected in parallel with the valve, and so that the vicinity of the front end of the vehicle body frame is not deformed by the extension force of the front end hydraulic jack, the pressure receiving area of the front end hydraulic jack side operating cylinder is made smaller than the pressure receiving area of the intermediate hydraulic jack side operating cylinder; In addition, a sequence valve that opens when the hydraulic pressure increases after the front end hydraulic jack is reduced, and a check valve that allows oil to return to the tank.
A control device for a hydraulic jack for vehicle body stabilization, characterized in that the intermediate hydraulic jack is inserted in parallel into a high-pressure side oil path between the intermediate hydraulic jack and its directional control valve when the intermediate hydraulic jack is contracted. 2 Hydraulic jacks for stabilizing the car body that can be extended to both sides are attached to the middle and rear ends of the car body frame in the longitudinal direction, respectively, and the front end of the car body frame is In a vehicle equipped with a swing crane that has reduced bending strength near the parts, a front end hydraulic jack is also attached to the front end of the vehicle body frame, and the operating cylinders of the front end hydraulic jack and the intermediate hydraulic jack are connected in parallel to one directional control valve, On the intermediate hydraulic jack side,
A signal generating device that emits a signal when the front end hydraulic jack is extended is installed, and a valve that opens only when the signal is received is installed in the high pressure side oil path between the front end hydraulic jack and its directional control valve when the front end hydraulic jack is extended. A sequence valve and a check valve that allow oil to return to the tank are inserted into the intermediate position between the intermediate hydraulic jack and its directional control valve, and a sequence valve that opens when the working pressure of the front end hydraulic jack increases after contraction and a check valve that allows oil to return to the tank. A control device for a hydraulic jack for vehicle body stabilization, characterized in that the hydraulic jack is inserted in parallel into a high-pressure side oil passage when the hydraulic jack is reduced.