JPH0353016Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a concrete pump equipped with a pair of concrete cylinders that are directly driven by a pair of main hydraulic cylinders and perform suction and discharge processes alternately. It is.

(Prior Art) In a conventional concrete pump, as shown in FIG. 3, high-pressure hydraulic oil obtained by the hydraulic pump 1 enters a hydraulic switching valve block 200, and is then transferred to the main hydraulic cylinders 8a, 8b. It is distributed to the cylinder 21 for driving the concrete valve.

The hydraulic switching valve block 200 includes a relief valve 2 provided on the discharge side of the hydraulic pump 1, a main hydraulic switching valve 400, a concrete valve driving switching valve 600, a switching valve D, 500, and a switching valve E, 30.
The main hydraulic switching valve 400 controls the flow of hydraulic oil to the main hydraulic cylinders 8a and 8b, and the pilot pressure of the main hydraulic switching valve 400 is generated when the concrete valve 19 is switched. Hydraulic pressure is taken out and supplied through regulating valves 202a, 202b and switching valves D and 500.

Here, the concrete valve driving switching valve 600
controls the flow of hydraulic oil to the driving cylinder 21 that drives the concrete valve 19. The pilot pressure to the switching valve 600 is supplied to the main hydraulic cylinder 8a,
8b through the pilot block 210 by heads C ₁ and C ₂ . Therefore, the concrete piston 1 is controlled by the main hydraulic switching valve 400.
2a, 12b, and the pistons 12a, 12
b is the stroke end, the main hydraulic cylinder 8a,
By the pilot pressure of heads C ₁ and C ₂ of 8b,
Controlling the concrete valve driving switching valve 600, driving the concrete valve 19 by switching the concrete valve driving switching valve 600,
The main hydraulic switching valve 400 is controlled by switching the concrete valve 19.

(Problem to be solved by the invention) The main hydraulic switching valve 400 is a concrete valve 1
Drive 9. Since it is controlled by the pilot pressure generated after the switching of the driving cylinder 21 is completed, the adjustment valve 20 is controlled by the switching speed of the concrete valve 19 or the difference in viscosity caused by changes in the oil temperature of the hydraulic oil.
It was difficult to control the throttle openings of the concrete valves 2a and 202b, and the timing at which the control valve 19 had been switched was ambiguous, resulting in the concrete valve 19 not being reliably switched and sometimes being left half-open.

In addition, the oil to the driving cylinder 21 that drives the concrete valve 19 is switched by the concrete valve driving switching valve 600, and the pilot pressure generated at the stroke end of the hydraulic pistons 9a, 9b of the main hydraulic cylinders 8a, 8b, Since the pilot pressure from the pilot block 210 controls the concrete valve driving switching valve 600, the subtle influence of the pilot pressure passing through the check valve 211 in the pilot block 210 controls the concrete valve driving switching valve 600. Since the switching of the 600 is controlled by a hydraulic pilot, there are very delicate aspects such as the influence of viscosity due to temperature rise of the hydraulic oil or the influence of dirt getting caught in the hydraulic oil.
Therefore, it is difficult to prevent and maintain the equipment, and there are also disadvantages such as increased costs when parts replacement equipment is required.

(Means for Solving the Problems) The present invention is an invention for solving the above-mentioned difficulties in conventional concrete pumps.
a pair of main hydraulic cylinders that are interlocked and connected to a pair of concrete cylinders via a piston rod;
A concrete pump comprising a driving cylinder for a concrete valve that alternately opens and closes both mouths of the concrete cylinder, a main hydraulic switching valve that switches the operation of the main hydraulic cylinder, and a switching valve that switches the operation of the driving cylinder. The main hydraulic switching valve has a three-position configuration including a neutral position of all port blocks, and the pair of main hydraulic cylinders and the drive cylinder have stroke start positions of the hydraulic piston of the main hydraulic cylinder and the piston of the drive cylinder. Alternatively, a sensor is provided to detect the end position, and the sensor is connected to each of the sensors, the solenoid valve of the main hydraulic pressure switching valve, and the solenoid valve of the driving cylinder, and the position detection signal from each sensor is used to detect the concrete valve. The present invention is characterized in that an electric control circuit is provided that returns the main hydraulic switching valve to a neutral position during switching and outputs a control signal to continue pump operation during the stroke of the concrete valve.

(Function) The present invention employs a three-position configuration for the main hydraulic switching valve of the main hydraulic cylinder, including the neutral position of the all-port block, and a stroke end sensor is provided on the main hydraulic cylinder and the cylinder for driving the concrete valve. By installing an electric control circuit that returns the main hydraulic switching valve to the neutral position during switching and an electric control circuit that continues pump operation during the concrete valve stroke, half-opening of the concrete valve and swinging of the concrete pump are prevented, and the pump Operation is accurate and reliability is significantly improved, switching is accurate and faster, pump efficiency is significantly improved, and noise, vibration, and hydraulic oil heat generation are reduced, which significantly improves pump performance. Eliminate the traditional drawbacks such as

(Example) Hereinafter, the present invention will be explained by referring to the illustrated example. An embodiment of the present invention is shown in Figs. 1 and 2. To explain the concrete pump and its hydraulic drive circuit shown in Fig. 1, 1 is the hydraulic pump, and 2 is the discharge side of the hydraulic pump. 3 is a solenoid valve that opens and closes the vent circuit of the relief valve 2 to unload and onload the entire hydraulic circuit; 4 is a pair of main hydraulic cylinders 8a;
The main hydraulic switching valve 4 is a main hydraulic switching valve that alternately supplies and discharges pressure oil by switching the hydraulic circuit of 8b, and the main hydraulic switching valve 4 has a configuration of three positions a, b, and c, with a neutral position c of the all port block. and when neither position a nor b is energized under the control of the electromagnetic valve 5, the concrete valve 19 is returned to the neutral position c during switching as will be described later. 6 is a concrete cylinder 10
A switching valve for valve driving that switches the hydraulic circuit of the switching cylinder 21 of the concrete valve 19 that alternately opens and closes both the openings (intake and discharge ports) of a and 10b, supplies and discharges pressure oil, and switches the valve 19. It's hot,
The switching valve 6 is configured to be controlled by a solenoid valve 7.

Further, 8a and 8b are a pair of main hydraulic cylinders, 9
a and 9b are hydraulic pistons of main hydraulic cylinders 8a and 8b, 10a and 10b are a pair of concrete cylinders, and 12a and 12b are concrete cylinders 1
0a, 10b concrete piston,
Hydraulic pistons 9a and 9b are connected to piston rod 11
Concrete piston 12 via a, 11b
concrete pistons 12a, 12b are connected to concrete pistons 12a, 12b to alternately suck in and discharge concrete. A hopper 18 is provided, and the hopper 1
8 is provided with a concrete valve 19 which alternately opens and closes both openings, and the concrete valve 19 is adapted to be switched and driven by a switching cylinder 21, and is configured as a concrete pump.

Furthermore, the main hydraulic pistons 9a, 9b are provided with sensors 101, 102 that detect when they have reached the stroke end and output a detection signal, and the driving cylinder 21 that switches the concrete valve is provided with a piston rod. Sensors or proximity switches 103 and 104 are provided oppositely to each other to detect the metal piece 23 provided at the tip of the metal piece 22b, detect both stroke ends thereof, and output a detection signal.

Next, the electric control circuit for controlling the concrete pump includes J-K flip-flops 500, 501, 502, 503 and logic gates OR gates 510, 511, 561, 5, as shown in FIG.
62, AND gate 520, 521, 563, 5
40,541,542,543, AND gate and
Composite gate 5 consisting of OR gates as shown
30, 531, NOT gate 564, drive elements 550, 551, 552, 553, 554, solenoid coils 60a, 60b, 40 of the solenoid valves 7, 5 of FIG. 1 driven by the drive elements.
a, 40b, solenoid coil 30 of the electromagnetic valve 3 in FIG. 1, detection signal input terminal 1010 of the sensor 101 in FIG. 1, detection signal input terminal 1020 of the sensor 102 in FIG. 1, sensor 10 in FIG.
3 (proximity switch) detection signal input terminal 103
0, the input terminal 1040 of the sensor 104 (proximity switch) in Fig. 1, the input terminals 1050 and 1060 of the "forward rotation" and "reverse rotation" signals from the concrete pump operation switch (not shown) (when the operation switch is '', no input is made to the input terminals 1050 and 1060).

Further, the structure of the illustrated embodiment of the present invention will be described in detail to explain its operation. In FIG.
AND gates 540-543 through 1,562
The solenoid coil 30 is energized by driving one input of the solenoid coil 30 . Now, when the concrete pump is in the state shown in FIG. 1, the sensor 103 is activated and its detection signal is input to the input terminal 1030 shown in FIG. At the same time as driving, the output of OR gate 511 also becomes high and AND gate 52
0 and drives the other input of the same AND gate 520
output becomes higher. On the other hand, since the Q of the slip-flop 503 is raised by the above-mentioned "normal rotation" signal, the upper output of the composite gate 531 in the figure becomes high, and the output of the AND gate 542 also becomes high, thereby energizing the solenoid coil 40a. By energizing the solenoid coils 30 and 40a, the main hydraulic switching valve 4 in FIG. 1 is switched to the left side in the drawing, and the main hydraulic piston 9a is advanced.

When the main hydraulic piston 9a reaches the stroke end, the sensor 101 detects it and outputs a signal, which is input to the input terminal 1010 in FIG. and OR
The output of gate 510 causes flip-flop 50
1 becomes higher, the upper output of the composite gate 530 becomes higher, and the solenoid coil 60 becomes higher as described above.
A is energized. When the solenoid coil 60a is energized, the switching valve 6 is switched to the right side in FIG. 1, the driving cylinder 21 begins to move, and the movement of the metal piece 23 turns on the sensor 104, causing the input shown in FIG. Since both terminals 1030 and 1040 have no input, the input and output of one of the AND gates 520 becomes low and the solenoid coil 40
The power supply to a is stopped. This causes the main hydraulic pressure switching valve 4 shown in FIG. 1 to return to the neutral position.

Furthermore, when the driving cylinder 21 operates and the switching of the concrete valve 19 is completed, the metal piece 2
3, the sensor 104 is activated and the detection signal is input to the input terminal 1040 in FIG. 2, and the solenoid coil 40b is energized by the same operation as described above, and the main hydraulic pressure switching valve 4 in FIG. 1 is switched to the right side in the figure. Then, contrary to the above, the main hydraulic piston 9b begins to move forward, leading to the next process. Thereafter, the same sequence is repeated, and the concrete pump is repeatedly driven back and forth.

Furthermore, when the input terminals 1030 and 1040 are both off while the concrete valve 19 is being switched, the output of the OR gate 511 is low.
In order to reverse the output of AND563 by NOT gate 564, at this time, the operation switch of the concrete pump is set to "stop" and the input terminal 10
50 and 1060 are both turned off, the output of OR gate 562 remains high and concrete valve 19 continues to switch until the switching is complete and a signal is present at either input terminal 1030 or 1040. When it enters, the output of the NOT gate 564 becomes low, the output of the AND gate 563, and the output of the OR gate 562 also becomes low, stopping the energization of the solenoid coil and stopping the concrete pump.

The illustrated embodiment of the present invention has the above-described configuration, so that while the concrete valve 19 is being switched, the main hydraulic switching valve 4 in the hydraulic circuit of the main hydraulic cylinders 8a and 8b is returned to the neutral position c. Because of this, the time required to switch to the next position is reduced to about 1/2 compared to switching to positions a and b at once, improving machine efficiency, saving energy, reducing noise, reducing vibration, and improving operation. In addition to achieving the effect of reducing oil heat generation,
Shaking of the concrete piston during switching of the concrete valve 19 can be prevented.

Since the main hydraulic switching valves 4 of the main hydraulic cylinders 8a and 8b have a three-position configuration with a neutral position c of the all-port block, only the main hydraulic switching valves 4 can operate the concrete piston 12a by the line internal pressure when the concrete pump is stopped. , 12b from retreating, and the main hydraulic pressure switching valve 4
During the switching, there is no unloading of the hydraulic circuit, and high oil pressure is obtained as the pilot pressure for controlling the switching valve, which ensures reliable switching operation and allows high-speed switching to reduce loss time.

Furthermore, since the concrete pump is controlled by electrical signals and the concrete valve is prevented from opening halfway, the performance and reliability of the concrete pump is improved, with fewer parts required, more accurate work, and significantly improved reliability. It has been significantly improved.

In the above embodiment, the neutral position c of the main hydraulic pressure switching valve 4 does not necessarily need to be a complete block mechanism as long as almost the same effect can be obtained, and the pump and tank sides may be semi-open. .

Further, the electric control circuit is not limited to the configuration shown in FIG. 2, but any element can be used as long as a similar sequence can be obtained, and it can be configured by software such as a sequencer.

The sensors 101, 102 and the sensors (proximity switches) 103, 104 are not particularly limited either, and various limit switches, photoelectric switches, etc. can be used as long as they can obtain the above-mentioned electrical signals.

(Effects of the invention) Since the concrete pump according to the invention has the above-mentioned configuration, the hydraulic circuit is an electric control circuit with a simpler structure than the conventional example that controls the hydraulic pilot pressure. A sensor for detecting the stroke end position of the hydraulic piston of the cylinder and a sensor for detecting the stroke end position of the drive cylinder are provided to improve the certainty and reliability of switching. (In other words, the delicate aspects caused by the viscosity of the hydraulic oil, etc. are eliminated, and reliable switching is performed.) In addition, by providing an electric control circuit, the main hydraulic switching valve can be returned to the neutral position during control valve switching, and the control valve can be switched easily. Speed-up and pump efficiency are significantly improved. (Conventionally, the valve switching speed was determined by the amount of oil immersion.) Furthermore, when the control valve is half-open (in conventional hydraulic pilot control, the pilot oil pressure controls the start of switching of the switching valve, Switching is performed reliably without problems such as half-opening, which occurs frequently and was a problem.

[Brief explanation of the drawing]

Fig. 1 is a mechanical diagram of the hydraulic circuit of a concrete pump showing an embodiment of the present invention, Fig. 2 is a mechanical diagram of the electric control circuit of Fig. 1, and Fig. 3 is a mechanical diagram of the hydraulic circuit of a concrete pump showing a conventional example. FIG. 4: Main hydraulic switching valve, 6: Drive switching valve, 8a,
8b: Main hydraulic cylinder, 9a, 9b: Main hydraulic piston, 10a, 10b: Concrete cylinder,
11a, 11b: Piston rod, 19: Concrete valve, 21: Driving cylinder, 30, 4
0b, 60a, 60b: Solenoid coil, 10
10, 1020, 1030, 1040, 105
0,1060: input terminal, 500,501,50
2,503: flip flop, 530,53
1: Composite gate, 550, 551, 552, 55
3,554: Drive element.

Claims (1)

[Scope of utility model registration request] A pair of main hydraulic cylinders that are interlocked and connected to a pair of concrete cylinders via piston rods, a driving cylinder for a concrete valve that alternately opens and closes both mouths of the concrete cylinders, and a main hydraulic pressure that switches the operation of the main hydraulic cylinders. In a concrete pump equipped with a switching valve and a switching valve that switches the operation of the driving cylinder, the main hydraulic switching valve has a three-position configuration with a neutral position of an all port block, and the main hydraulic switching valve has a three-position configuration with a neutral position of an all port block, The hydraulic piston of the main hydraulic cylinder and the piston of the driving cylinder are provided with sensors for detecting the stroke start or end positions of the hydraulic piston of the main hydraulic cylinder and the piston of the driving cylinder, respectively. Electricity connected to the valves and outputting a control signal to return the main hydraulic switching valve to the neutral position during switching of the concrete valve and to continue pump operation during the middle of the stroke of the concrete valve according to the position detection signal from each of the sensors. A concrete pump characterized by being equipped with a control circuit.