JPS582920B2 - Soft stop device for undulating bodies in aerial work vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a soft stopping device for an undulating body in an aerial work vehicle.

Generally, in high-altitude work vehicles such as ladder vehicles, vehicles with bending towers, and crane vehicles, the raising and lowering of undulating bodies such as ladders, towers, booms, arms, etc. is performed using hydraulic power.

Conventionally, in the above-mentioned hydraulic operation, a method is known in which a solenoid valve is used to switch the operating valve.

However, when a solenoid valve is used, the spool is switched rapidly and the hydraulic passage is switched instantaneously, which inevitably causes a severe shock at the end of the operation, making the work extremely dangerous.

Therefore, in order to eliminate the above-mentioned drawbacks, even if the hydraulic passage when fully opened is narrowed and the shock generated when switching the solenoid valve is minimized,
Since the hydraulic passage is constricted when fully opened, the raising and lowering operation is naturally delayed, which has the disadvantage that the time required for the operation is longer than necessary.

In view of the above-mentioned drawbacks of the conventional art, the present invention aims to improve and eliminate these problems by gradually reducing the amount of pressure oil supplied as the undulating body reaches the end of its motion, thereby eliminating the impact that occurs at the end of the undulating body's motion. The purpose of this is to sufficiently widen the passage area during operation to increase the operating speed and improve work efficiency.

The configuration of the present invention will be explained below with reference to the drawings.

First, the undulating device for the undulating body in the high-altitude work vehicle according to the present invention will be explained using a ladder vehicle as an example.

In Fig. 1, 1 is the vehicle body, 2 is a turntable installed at the rear of the vehicle, and a triangular frame 3 is mounted on the center of the turntable.
A ladder operation platform 4 is installed on the side.

Reference numeral 5 denotes a ladder tilt correction frame, whose root portion is pivotally mounted on the triangular frame 3 via a pivot 6 so that it can be raised and lowered freely.

The lowest rung of the telescoping ladder 7 is fixedly supported on this ladder inclination correction frame 5.

The ladder 7 is raised and lowered by a ladder raising and lowering hydraulic cylinder 8 interposed between the triangular frame 3 and the ladder tilt correction frame 5.

Further, the ladder 7 is equipped with a ladder telescopic hydraulic cylinder (not shown) interposed between the second ladder from the bottom and the ladder tilt correction frame 5, or a rope winding drum (not shown) coaxially installed on the pivot shaft 6. (not shown) for telescopic operation.

Reference numeral 9 designates a ladder elevation angle setting mechanism, in which a dial-type ladder elevation angle setting knob 11 connected to a ladder elevation angle setting potentiometer 10 is provided on the ladder operating table 4, and by rotating this, the ladder elevation angle setting corresponding to the knob 11 is set. The angle is extracted as a voltage from the potentiometer 10.

Reference numeral 12 denotes a ladder elevation angle detection mechanism, which includes a pivot shaft 6 that fits the ladder inclination correction frame 5 of the ladder 7 at a predetermined angle, and a rotary shaft 1 connected to a ladder elevation angle detection potentiometer 13.
4 and the subrocket wheel 15,
16 and an endless chain 17, the pivot shaft 6 is rotated as the ladder 7 moves up and down, and the rotary shaft 14 is rotated in synchronization, so that the detection ladder elevation angle corresponding to the rotation of the pivot shaft 6 is detected by the voltage from the potentiometer 13. It is taken out as

18 is an operating valve that controls the hydraulic circuit of the ladder hoisting hydraulic cylinder 8, and its spool 19 is connected to the bracket 20 on the housing.
It is fixed in the middle of the switching lever 21 which is pivotally connected to the switch lever 21.

Reference numeral 22 denotes a ladder hoisting operation lever which is pivotally connected to the upper part of the ladder operation platform 4 via a shaft 23, and which is connected to the switching lever 21 via a connecting rod 24.
It is connected to the tip of.

When the operating lever 22 is tilted from the neutral position to the standing or falling side, the spool 19 of the operating valve 18 is moved from the neutral position to the lower or upper switching position, and the ladder 7 is operated to rise or fall.

A master cylinder 25 is installed close to the operating valve 18, and its piston rod 26 is fixed in the middle of the switching lever 21.

27 is a solenoid valve that operates the master cylinder 25; 28
is an electromagnetic coil for switching the voltage, which corresponds to the voltage corresponding to the set ladder undulation angle taken out from the potentiometer 10 of the ladder undulation angle setting mechanism 9 and the detected ladder undulation angle taken out from the potentiometer 13 of the ladder undulation angle detection mechanism 12. The voltage is compared, and when the difference between both voltages is zero, the magnet is energized.

Next, the operating state of the above configuration will be explained.

First, the ladder elevation angle is set by rotating the ladder elevation angle setting knob 11 on the ladder operating table 4.

Then, a voltage proportional to the set amount of the ladder elevation angle corresponding to the position of the knob 11 can be extracted from the potentiometer 10.

When the instruction for setting the ladder elevation angle is completed, the operator operates the operating lever 22 on the ladder operating table 4 to raise and lower the ladder.

That is, when the electromagnetic coil 28 of the solenoid valve 27 is not energized, the operating lever 22 can be operated up and down without being restrained by the master cylinder 25, and when it is tilted from the neutral position to the upright or inverted side, the operating lever 18 spool 1
9 moves from the neutral position to the lower or upper switching position, high pressure oil is supplied to the ladder hoisting hydraulic cylinder 8, and the piston rond of the hydraulic cylinder 8 expands or contracts, and the ladder 7 moves through the ladder tilt correction frame 5. To be raised or laid down.

Then, as the ladder 7 rises or falls, the pivot shaft 6 is rotated, and the rotating shaft 14 is synchronously rotated at an amplified rotation angle via the sprocket wheels 15, 16 and the endless chain 17, so that it corresponds to the position of the ladder 7. A voltage proportional to the detected amount of the ladder elevation angle can be extracted from the potentiometer 13.

When the piston rond of the ladder hoisting hydraulic cylinder 8 is sequentially expanded or contracted and the ladder 7 is raised or lowered to the set ladder hoisting angle, the voltage and ladder hoisting angle are taken out from the potentiometer 10 of the ladder hoisting angle setting mechanism 9. The voltage taken out from the potentiometer 13 of the detection mechanism 12 becomes equal, and the electromagnetic coil 28 of the electromagnetic valve 27 is energized and excited.

Then, the solenoid valve 27 switches and the master cylinder 25
Since high-pressure oil is supplied to the piston rod 26 and the piston rod 26 moves up and down, even if the operating lever 22 is tilted to the upright side and the switching lever 21 is bent downward, the operating lever 22 will not be tilted to the lodging side. Even if the switching lever 21 is bent upward, the switching lever 21 is returned to the neutral position by the displacement of the piston rod 26, and the spool 1 of the operating valve 18
9 returns to the neutral position from the upper or lower switching position, the supply of high pressure oil to the ladder hoisting hydraulic cylinder 8 is stopped, the extension or contraction of the piston rod of the ladder hoisting hydraulic cylinder 8 is stopped, and the ladder 7 is switched to the setting ladder. The undulation or lodging is stopped at the undulation angle.

At this time, the switching lever 21 is returned to the neutral position, and at the same time, the operating lever 22 is also returned to the neutral position via the connecting rod 24.

The above is the levying device for the undulating body in the aerial work vehicle according to the present invention.Next, the soft stopping device for the undulating body, which constitutes the main part of the present invention, will be explained.

That is, the hydraulic circuit of the ladder hoisting hydraulic cylinder 8 is configured as shown in FIG.

As shown in FIG.
8 with piping 29, 30, and a balancing valve 31 is installed in the middle of the piping 29 connected to the front chambers 8'', 8'' of the hydraulic cylinders 8, 8.
An electromagnetic flow control valve 32 is installed in a pipe 30 connected to the rear chambers 8', 8' of 8.

The balancing valve 31 is used to prevent the ladder 7 in an upright state from moving on its own due to its own weight and falling down, and the pressure oil in the front chambers 8'', 8'' of the hoisting hydraulic cylinders 8, 8 is It is designed to prevent backflow.

The electromagnetic flow control valve 32 changes the flow rate proportional to the input current, and the amount of current energized to the solenoid is determined by the output voltage of the ladder elevation angle setting mechanism 9 and the ladder elevation angle detection mechanism 12.
The displacement occurs according to the voltage difference between the output voltage and the output voltage.

In addition, 33 and 33 are pilot operated check valves, 34 is a bypass pipe that bypasses the balancing valve 31, and 35, 3
6 is a cock, the cock 35 is normally open, and the cock 36 is normally closed.

Since the hydraulic circuit of the ladder hoisting hydraulic cylinder 8 is configured as described above, the voltage difference between the output voltage of the ladder hoisting angle setting mechanism 9 and the output voltage of the ladder hoisting angle detection mechanism 12 is large at the initial stage of the hoisting operation of the ladder 7. Since the input current to the solenoid of the electromagnetic flow control valve 32 is large and the flow rate of the electromagnetic flow control valve 32 is high, the raising and lowering is performed quickly, and as the ladder 7 reaches the end of its raising and lowering operation, the ladder raising and lowering angle setting mechanism 9 changes. Since the voltage difference between the output voltage and the output voltage of the ladder elevation angle detection mechanism 12 gradually decreases, the input current to the solenoid of the electromagnetic flow control valve 32 gradually decreases, and the flow rate of the electromagnetic flow control valve 32 gradually decreases. As a result, the ladder 7 is gradually raised and lowered, and the impact at the moment when the ladder is completed is alleviated.

As explained above, the present invention includes a levitation angle setting mechanism that sets the undulation angle of a undulation body using a voltage corresponding to the undulation angle, a levitation angle detection mechanism that detects the undulation angle of the undulation body using a voltage corresponding to the undulation angle, and a levitation angle detection mechanism that detects the undulation angle of the undulation body using a voltage corresponding to the undulation angle. The system includes an automatic undulation stop mechanism that compares the output voltage of the mechanism with the output voltage of the undulation angle detection mechanism and automatically stops the undulation of the undulation body when the difference between both voltages is zero, After giving a setting instruction, operate the operating lever to raise or lower the undulating object, detect the undulation angle of the undulating object by operating the undulating object, and automatically raise or lower the undulating object when the undulating object reaches the specified undulating angle. In an aerial work vehicle equipped with a hoisting device for a hoisting body that can stop the hoisting body, a part of the piping connecting the hydraulic cylinder for hoisting the hoisting body and the operation valve provided on the operation platform on the turntable is connected to the hoisting device. Since we are equipped with an electromagnetic flow control valve that can obtain a flow rate proportional to the current generated by the voltage difference between the output voltage of the body's undulation angle setting mechanism and the output voltage of the undulation angle detection mechanism, the undulation body is gradually controlled at the end of its operation. Therefore, it is possible to eliminate the shock that occurs at the end of operation, and during operation, it is possible to sufficiently fill the hydraulic oil passage area to increase the operation speed and improve work efficiency. can.

[Brief explanation of the drawing]

FIG. 1 is a side view of the essential parts of a ladder hoisting device for a ladder vehicle, illustrating an embodiment of the hoisting device for a hoisting body for an elevated work vehicle according to the present invention, and FIG. It is a hydraulic circuit diagram. 8,8...Ladder hoisting hydraulic cylinder, 18...
...Operation valve, 29,30...Piping, 31.
... Balancing valve, 32 ... Solenoid flow control valve.

Claims (1)

[Claims] 1. A undulation angle setting mechanism that sets the undulation angle of the undulation body with a voltage corresponding to the undulation angle, a undulation angle detection mechanism that detects the undulation angle of the undulation body with a voltage corresponding to the undulation angle, and an output voltage of the undulation angle setting mechanism and the undulation angle. It consists of an automatic hoisting stop mechanism that compares the output voltage of the angle detection mechanism and automatically stops the hoisting of the hoisting object when the difference between both voltages is zero. The undulating body is capable of undulating by operating a lever, detecting the undulating angle of the undulating body by operating the undulating body, and automatically stopping the undulating body when the undulating body reaches the set and instructed undulating angle. In an aerial work vehicle equipped with a hoisting device, a part of the piping connecting the hydraulic cylinder for hoisting the hoisting body and the operation valve provided on the operation platform on the turntable is equipped with a hoisting angle setting mechanism for the hoisting body. A soft stop device for a lifting body in an aerial work vehicle, characterized by being equipped with an electromagnetic flow control valve that obtains a flow rate proportional to the current generated by the difference between the output voltage and the output voltage of a lifting angle detection mechanism. .