JPH0549824B2 - - Google Patents

Description

Detailed Description of the Invention A. Object of the Invention (1) Industrial Field of Application The present invention provides a method for alternately reciprocating pump pistons in a pair of pump cylinders by operating a pair of hydraulic cylinders for driving the pumps. The present invention also relates to a drive control device for a concrete pump that continuously pumps concrete in a hopper.

(2) Prior Art FIG. 4 is a schematic diagram showing the structure of a conventional concrete pump.

As shown in the figure, a pair of pump driving hydraulic cylinders 10a and 01b have a center box 02.
A pair of pump cylinders 03a, 03b are connected via the hydraulic cylinders 01a, 01b.
The pump pistons 05 of the pump cylinders 03a, 03b corresponding to the hydraulic pistons 04a, 04b of
a, 05b are connecting rods 06a, 06, respectively.
They are connected together by b. At the ends of the pump cylinders 03a, 03b opposite to the center box 02, there are valve cylinders 07a, 07b.
A valve 08 is installed which is reciprocally driven in conjunction with the hydraulic cylinders 01a and 01b, and the pump cylinder 03 is driven by this valve 08.
The respective ends of a and 03b are arranged to alternately communicate with a hopper and a discharge pipe 09 (not shown).

Each hydraulic cylinder 01a, 01b is connected to a front chamber 010a, 011 by a hydraulic piston 04a, 04b.
a and base chambers 010b, 011b, and ports are provided in these tip chambers 010a, 011a and base chambers 010b, 011b, respectively. Then, 3 for the hydraulic pump P and tank T.
By appropriately communicating the two high-pressure oil passages and low-pressure oil passages 013a, 013b that communicate with the four ports via the position switching valve 012, each hydraulic cylinder 01a, 01b can be caused to move in a desired mode. It's starting to make people do things.

That is, in the low-pressure large-capacity mode in which a large amount of concrete is supplied at low pressure, each hydraulic cylinder 01
The ports of the base chambers 010b, 011b of the a, 01b are communicated with each other, and the ports of the tip chambers 010a, 01b are communicated with each other.
The ports of 11a are connected to oil passages 013a and 013, respectively.
connected to b. In this state, when the 3-position switching valve 012 is switched to the left and right positions, pressure oil is alternately supplied to both tip chambers 010a and 011a, which are the sides with smaller pressure receiving areas of the hydraulic pistons 04a and 04b, and a large amount of concrete is handled at low pressure. can be supplied.

In addition, in the high pressure small capacity mode where a small amount of concrete is supplied at high pressure, each hydraulic cylinder 01
The ports of the tip chambers 010a, 011a of the a, 01b are communicated with each other, and the ports of the base chambers 010b, 01b are communicated with each other.
The ports of 11b are connected to oil passages 013a and 013, respectively.
connected to b. In this state, when the 3-position switching valve 012 is switched to the left and right positions, pressure oil is alternately supplied to both base chambers 010b and 011b, which are the sides with larger pressure receiving areas of the hydraulic pistons 04a and 04b, and a small amount of concrete is heated at high pressure. can be supplied.

By the way, in this type of concrete pump, hydraulic cylinders 01a, 01a, 03b are removed and replaced with worn pump cylinders 03a, 03b.
01b, the pump cylinders 03a, 03b
The pump pistons 05a, 05b are moved to the center box 02 by the hydraulic cylinders 01a, 01b in order to push the pump pistons 05a, 05b out from the valve 08 side or to replace the packing of the pump pistons 05a, 05b.
There may be cases where work is required to pull it out inside. In such a case, it is necessary to simultaneously drive the pair of hydraulic cylinders 01a, 01b in the same direction in order to perform the work efficiently.

Therefore, in the above-mentioned push-out mode and pull-out mode performed during maintenance work, the tip chamber 01 of each hydraulic cylinder 01a, 01b is
0a, 011a, and the base chamber 010b,
011b are connected to each oil passage 013a, 013b. In this state, when the three-position switching valve 012 is switched left and right, the pair of hydraulic cylinders 01a and 01b are simultaneously driven to expand and contract in the same direction.

(3) Problems to be Solved by the Invention However, in conventional concrete pumps, four ports of the hydraulic cylinders 01a and 01b and two
It was necessary to change the piping connecting the main oil passages 013a and 013b each time, and a great deal of effort and time was spent on this work.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to easily switch between low-pressure large-capacity mode, high-pressure small-capacity mode, pull-out mode, and extrusion mode without rearranging piping. The technical problem is to provide a drive control device for a concrete pump.

B. Structure of the Invention (1) Means for Solving the Problems In order to solve the above problems, the present invention provides a system in which pistons in a pair of pump cylinders connected to one discharge pipe via a valve are connected to each other through a valve. In a concrete pump that is reciprocally driven by a pair of hydraulic cylinders; one of the two oil passages connected to the hydraulic pump and the tank is connected to the tip chamber and base chamber of the first hydraulic cylinder via first and second logic valves. and the other side of the oil passage is connected to a third,
The tip chamber and the base chamber of the second hydraulic cylinder are communicated through a fourth logic valve, and the tip chamber and the base chamber of the first and second hydraulic cylinders are communicated with each other through a fifth and sixth logic valve. and connect
By opening and closing these first to sixth logic valves using two three-position switching valves, the tip chamber and base chamber of the first and second hydraulic cylinders and the two oil passages are selected. The first priority is to communicate and cut off
The characteristics of

In addition to the first feature, the present invention also provides a fifth logic valve that is installed in a rod cover that covers the front chambers of a pair of hydraulic cylinders, and a first logic valve that is installed in a main block that is disposed on the upper part of the rod cover. A second feature is that a fourth logic valve and two three-position switching valves are installed, and a sixth logic valve is further installed in a head cover that covers the base chambers of the pair of hydraulic cylinders.

(2) Effect According to the first feature of the present invention having the above-described configuration, the first
~ By communicating the tip chambers of both hydraulic cylinders with each oil passage through the fourth logic valve, and communicating the base chambers of both hydraulic cylinders with each other through the fifth and sixth logic valves, the low pressure large capacity mode is achieved. Concrete will be supplied. Also, a pair of 3
By switching the position switching valve, the base chambers of both hydraulic cylinders are communicated with each oil passage through the first to fourth logic valves, and the front chambers of both hydraulic cylinders are connected to each other through the fifth and sixth logic valves. By communicating with each other, concrete is supplied in a high-pressure, small-volume mode. Further, by switching the pair of three-position switching valves, the tip chambers and the base chambers of both hydraulic cylinders are communicated with each other via the fifth and sixth logic valves, and the above-mentioned communication is established via the first to fourth logic valves. The drawing mode and the pushing mode are executed by communicating the tip chambers of both hydraulic cylinders with one oil passage and the base chambers of both hydraulic cylinders with the other oil passage.

According to the second feature of the present invention, in addition to the above-mentioned effects, the logic valve for switching between four modes and the three-position switching valve are arranged in a rational positional relationship, making the entire concrete pump compact. can be formed into

(3) Embodiment Hereinafter, an embodiment of the drive control device for a concrete pump according to the present invention will be described based on the drawings.

Figure 1 shows the hydraulic circuit for controlling the concrete pump. Between the high-pressure oil line 1a connected to the discharge side of the hydraulic pump P and the low-pressure oil line 1b that returns to the tank T, there is a hydraulic circuit for driving the pump piston of the concrete pump. Four hydraulic cylinder logic valves 3 that selectively supply pressure oil to a pair of hydraulic cylinders 2a and 2b.
a, 3b, 3c, 3d, and a pair of valve cylinders 4a, 4b for driving valves of the concrete pump.
Four valve logic valves 5a, 5b, 5c, and 5d are provided to selectively supply pressure oil to the valves.

A pair of hydraulic cylinder oil passages 6 are connected to the hydraulic cylinder logic valves 3a, 3b and 3c, 3d.
a, 6b extend, and one hydraulic cylinder oil passage 6a is connected to two oil passage switching logic valves 7a, 7.
The oil passages 8a and 8b branch into two oil passages 8a and 8b via the oil pressure cylinder 2a, and the oil passages 8a and 8b are connected to a tip chamber 9a and a base chamber 9b of the hydraulic cylinder 2a, respectively. The other hydraulic cylinder oil passage 6b is connected to two oil passages 8 via two oil passage switching logic valves 7c and 7d.
The oil passages 8c and 8d are branched into a base chamber 10b and a tip chamber 10a of the hydraulic cylinder 2b, respectively.
is connected to. Furthermore, hydraulic cylinders 2a, 2b
The front chambers 9a, 10a of the hydraulic cylinders 2a, 2b are connected to each other via a fifth oil passage switching logic valve 7e, and the base chambers 9b, 10 of the hydraulic cylinders 2a, 2b are connected to each other via a fifth oil passage switching logic valve 7e.
b is the sixth oil path switching logic valve 7f
connected via.

The pilot oil passages 11a and 11b connected to the high pressure oil passage 1a and the low pressure oil passage 1b are connected to the valve cylinder 4 via the first main solenoid valve 12a, which is a three-position switching valve, and the pilot oil passages 13a and 13b.
It is connected to the hydraulic cylinder logic valves 3a, 3b, 3c, and 3d via a pilot switching valve 14a, which is a two-position switching valve connected to the hydraulic cylinders 3a, 4b. Therefore, by switching the first main solenoid valve 12a and the pilot switching valve 14a, the
The hydraulic cylinder oil passages 6a and 6b are connected to the high pressure oil passage 1a through the hydraulic cylinder logic valves 3a to 3d.
and can be selectively connected to the low pressure oil passage 1b.

Further, the pilot oil passages 15a and 15b connected to the high pressure oil passage 1a and the low pressure oil passage 1b are connected to six oil passage switching logic valves 7a to 7 via a first sub-solenoid valve 16a and a second sub-solenoid valve 16b.
By switching these two sub solenoid valves 16a and 16b, the high pressure oil passage 1a and the low pressure oil passage 1b are connected to the pair of hydraulic cylinders 2.
Tip chambers 9a, 10a and base chambers 9b, 1 of a, 2b
0b to switch between the four modes described above.

On the other hand, the logic valves 5a and 5b are connected to the valve cylinder 4a via a valve oil passage 17a, and the logic valves 5c and 5d are connected to the valve cylinder 4a via a valve oil passage 17a.
is connected to the valve cylinder 4 via the valve oil passage 17b.
connected to b.

The pilot oil passages 18a and 18b connected to the high pressure oil passage 1a and the low pressure oil passage 1b are connected to the hydraulic cylinder 2 via the second main solenoid valve 12b, which is a three-position switching valve, and the pilot oil passages 19a and 19b.
This is a two-position switching valve connected to the front chambers 9a and 10a of the valves a and 2b. The valve logic valves 5a, 5b, 5c, 5d are connected via the pilot switching valve 14b.
It is connected to the. Therefore, by switching the second main solenoid valve 12b and the pilot switching valve 14b, the four valve logic valves 5a to 5
The high pressure oil passage 1a and the low pressure oil passage 1b can be selectively connected to the valve cylinder 4a and the valve cylinder 4b via d.

Further, a relief valve 20 is provided between the high pressure oil passage 1a and the low pressure oil passage 1b, and is configured to relieve excess pressure generated in the high pressure oil passage 1a to the low pressure oil passage 1b.

Figures 2a and 2b show the mounting positions of each valve for mode switching in the concrete pump.

As is clear from the figure, the hydraulic cylinders 2a,
A sixth oil passage switching logic valve 7f is installed inside the head cover 21 that covers the base chambers 9b and 10b of the hydraulic cylinders 2a and 2b.
A fifth oil passage switching logic valve 7e is installed inside a rod cover 22 that covers the front chambers 9a and 10a of the oil passage 2b. Inside the main block 23 provided on the upper part of the rod cover 22, there are other first to fourth oil passage switching logic valves 7a, 7b, 7c, and 7d, and these six oil passage switching logic valves. 1st and 2nd sub-solenoid valves 16a and 16b for controlling 7a to 7d
is installed.

FIG. 3 shows the first and second main solenoid valves 12a,
12b and the first and second sub solenoid valves 16a, 1
6b shows a relay circuit for controlling 6b.

As is clear from the figure, a common contact A of a forward/reverse switch 25 for switching the discharge direction of the concrete pump is connected to the power supply line 24a, and contacts B,
Relay coils R ₁ and R ₂ are interposed between C and the power line 24b, respectively. Moreover, between the power supply lines 24a and 24b, a first
The coil S ₁ of the main solenoid valve 12a and the coil S ₂ of the second main solenoid valve 12b are connected to the relay coil.
It is interposed in series with relay contact r ₁ of R ₁ , and
The coil _S3 of the first main solenoid valve 12a and the coil _S4 of the second main solenoid valve 12b are connected in parallel.
It is interposed in series with the relay contact _r2 of the relay coil _R2 .

Furthermore, the power supply line 24a has a common contact D of a mode changeover switch 26 for switching the concrete pump between a low-pressure large-capacity mode and a high-pressure small-capacity mode.
is connected, and this mode selector switch 26
A coil Sa of the first sub-solenoid valve 16a and a coil of the second sub-solenoid valve 16b are connected in parallel between the contacts E, F and the power line 24b, respectively.
Sb, and a coil Sc of the first sub solenoid valve 16a and a coil Sd of the second sub solenoid valve 16b connected in parallel are interposed.

Next, the operation of one embodiment of the drive control device for a concrete pump according to the present invention having the above-described configuration will be described.

When the concrete pump is normally used, that is, when concrete is supplied from the hopper in a low-pressure, large-capacity mode, the common terminal A of the forward/reverse changeover switch 25 is connected to the terminal B, and the relay coil R is ₁ is energized and relay contact r ₁ is closed, so that coils S ₁ and S ₂ are in an energized state. In addition, the common terminal D of the mode changeover switch 26 is connected to the terminal E, and the coils Sa, Sb
is in an excited state. Therefore, in FIG. 1, the first main solenoid valve 12a and the second main solenoid valve 12b are both switched to the left position, and the first sub solenoid valve 16a and the second sub solenoid valve 16b are also switched to the left position. It's on.

When the pilot switching valves 14a and 14b are both in the left position, the pressure in the high pressure oil passage 1a is the same as that of the pilot oil passage 11a, the first main solenoid valve 12a,
The hydraulic cylinder logic valves 3a, 3c are closed via the pilot switching valve 14a, and at the same time, the hydraulic cylinder logic valves 3b, 3d are opened to the low pressure oil path 1b. Therefore, the logic valve 3d for hydraulic cylinder
The hydraulic cylinder oil passage 6b communicating with the high pressure oil passage 1a via the hydraulic cylinder logic valve 3b is on the high pressure side, and the hydraulic cylinder oil passage 6a communicating with the low pressure oil passage 1b via the hydraulic cylinder logic valve 3b is on the low pressure side. At this time, since the first sub-solenoid valve 16a and the second sub-solenoid valve 16b are both in the left position, the three oil passage switching logic valves 7b, 7c, 7e are connected to the high pressure oil passage 1a via the pilot oil passage 15a. The other three oil passage switching logic valves 7a, 7d, 7f communicate with the low pressure oil passage 1b via the pilot oil passage 15b, and the base chambers 9b, 10b are communicated with each other.

Therefore, the pressure oil supplied from the hydraulic pump P to the hydraulic cylinder oil passage 6b on the high pressure side via the hydraulic cylinder logic valve 3d is transferred to the hydraulic cylinder 2b with a small pressure receiving area via the oil passage switching logic valve 7d. is supplied to the tip chamber 10a, and the hydraulic cylinder 2
b is contracted at high speed. At the same time, hydraulic cylinder 2
The pressure oil pushed out from the base chamber 10b is transferred to the hydraulic cylinder 2a via the oil path switching logic valve 7f.
is supplied to the base chamber 9b of the hydraulic cylinder 2a to extend the hydraulic cylinder 2a. Further, the tip chamber 9a of the hydraulic cylinder 2a
The pressure oil pushed out from the oil passage is transferred to the oil passage 6a for the low pressure side hydraulic cylinder via the oil passage switching logic valve 7a.
Reflux to.

In this way, when the stroke of the hydraulic cylinders 2a, 2b in one direction is completed, the hydraulic cylinder 2
Pilot oil passage 19 connected to the tip chamber 10a of b
The pressure at point b increases and switches the pilot switching valve 14b to the right position. Then, the pressure in the high pressure oil passage 1a is applied to the pilot oil passage 18a, the second solenoid valve 12b in the left position, and the pilot switching valve 1 in the right position.
Logic valves 5a, 5 for two valves via 4b
Close the logic valve 5 for the other two valves.
b, 5d are communicated with the low pressure oil passage 1b. Then, the pressure oil from the high pressure oil path 1a flows through the valve logic valve 5d,
Valve cylinder 4b via valve oil passage 17b
Pressure oil is supplied to the valve cylinder 4b to extend the valve cylinder 4b, and is pushed out from the contracting valve cylinder 4a. The pressure oil is returned to the low pressure oil passage 2b via the valve oil passage 17a and the valve logic valve 5b.

In this way, when the valve cylinders 4a and 4b are switched, the pressure in the pilot oil passage 13b connected to the valve cylinder 4b increases, and the pilot switching valve 14a is switched to the right position. Then, the hydraulic cylinder oil passage 6a becomes the high pressure side and the hydraulic cylinder oil passage 6b becomes the low pressure side, so the pressure oil flows in the opposite direction as described above, the hydraulic cylinder 2a contracts, and the hydraulic cylinder 2b expands. A stroke in the opposite direction is performed. Upon completion of this stroke, the pilot oil passage 19a connected to the tip chamber 9a of the hydraulic cylinder 2a becomes high pressure, the pilot switching valve 14b is switched to the initial left position, and the valve cylinders 4a and 4b are driven in the opposite direction. .

As described above, the valve cylinders 4a, 4b
The hydraulic cylinders 2a and 2b each make one reciprocation while switching between the two, completing one cycle of driving, and by continuously performing this cycle, concrete is pumped in the low-pressure large-capacity mode.

Next, in order to perform the high voltage small capacity mode used when it is necessary to supply concrete at high pressure, in Fig. 3, connect the common terminal of the forward/reverse changeover switch 25 to the same terminal B as before, and While keeping both the main solenoid valve 12a and the second main solenoid valve 12b in the left position, switch the mode changeover switch 2.
Connect the common terminal D of 6 to the opposite terminal F and energize the coils Sc and Sd. Then, the first sub solenoid valve 16a and the second sub solenoid valve 16
b are both switched to the right position, and the three oil passage switching logic valves 7a, 7d, 7f communicate with the high pressure oil passage 1a via the pilot oil passage 15a and close.
Other three oil path switching logic valves 7b, 7
c, 7e communicate with the low pressure oil passage 1b via the pilot oil passage 15b, and both hydraulic cylinders 2
The front chambers 9a and 10a of a and 2b are communicated with each other. Therefore, the pressure oil supplied from the hydraulic pump P to the hydraulic cylinder oil passage 6b on the high pressure side via the hydraulic cylinder logic valve 3d is transferred to the hydraulic cylinder 2b having a large pressure receiving area via the oil passage switching logic valve 7c. It is supplied to the base chamber 10b and causes the hydraulic cylinder 2b to extend at a low speed. At the same time, the pressure oil pushed out from the front chamber 10a of the hydraulic cylinder 2b is transferred to the hydraulic cylinder 2 through the oil path switching logic valve 7e.
The oil is supplied to the tip chamber 9a of the hydraulic cylinder 2a, and the hydraulic cylinder 2a is contracted. In addition, the base chamber 9 of the hydraulic cylinder 2a
The pressure oil pushed out from b is transferred to the oil passage 6 for the hydraulic cylinder on the low pressure side via the oil passage switching logic valve 7b.
Reflux to a.

When the stroke of the hydraulic cylinders 2a, 2b in one direction is completed, the pilot switching valve 14b is switched to the right position to drive the valve cylinders 4a, 4b, and then the pilot switching valve 14a is switched to the right position. Switch the hydraulic cylinder 2a,
2b makes a stroke in the opposite direction. When the stroke of the hydraulic cylinders 2a, 2b in the opposite direction is completed, the pilot switching valve 14b is switched to the left position, the valve cylinders 4a, 4b are driven in the opposite direction, and one cycle of driving is completed.

In addition, in the above-mentioned low voltage large capacity mode and high voltage small capacity mode, when the common contact A of the forward/reverse switch 25 is switched to the contact C side, the relay coil R ₂
is energized and relay contact _r2 is closed, so that coils _S2 and _S4 are energized, and the first main solenoid valve 12a
Both the second main solenoid valves 12b are switched to the right position, and the positional relationship between the high pressure oil passage 1a and the low pressure oil passage 1b can be reversed. Therefore, if the concrete pump is driven in this state, the concrete in the discharge pipe can flow back toward the hopper.

Next, in order to perform the withdrawal mode in which the hydraulic cylinders are simultaneously contracted, as shown in FIG. While keeping both valves 12b in the left position, the common terminal D of the mode changeover switch 26 is disconnected from both terminals E and F, and all coils Sa, Sb, Sc, and Sd are demagnetized. Then, the first sub solenoid valve 16a
and the second sub-solenoid valve 16b are both switched to the center position, the two oil passage switching logic valves 7a and 7c are closed and communicated with the high pressure oil passage 1a via the pilot oil passage 15a, and the other four logic valves 7a and 7c are closed. The oil passage switching logic valves 7b, 7d, 7e, and 7f are communicated with the low pressure oil passage 1b via the pilot oil passage 15b. Then, the pressure oil supplied from the hydraulic pump P to the hydraulic cylinder oil passage 6b on the high pressure side via the hydraulic cylinder logic valve 3d is transferred to the tip chamber 10a of the hydraulic cylinder 2b via the oil passage switching logic valves 7d and 7e. is supplied to the tip chamber 9a of the hydraulic cylinder 2a, and at the same time, the base chamber 1 of the hydraulic cylinder 2b is supplied to the tip chamber 9a of the hydraulic cylinder 2a.
0b and the pressure oil pushed out from the base chamber 9b of the hydraulic cylinder 2a is transferred to the oil path switching logic valves 7f and 7b.
The oil flows back to the low-pressure side hydraulic cylinder oil passage 6a through. Therefore, both hydraulic cylinders 2a and 2b contract simultaneously.

Next, in order to perform the extrusion mode in which the hydraulic cylinders are simultaneously extended, as shown in FIG. Switch both solenoid valves 12b to the right position, disconnect the common terminal D of the mode changeover switch 26 from both terminals E and F as before, and connect all coils Sa, Sb,
Demagnetize Sc and Sd. Then, the six oil passage switching logic valves 7a to 7f remain the same as in the above-mentioned draw-out mode, and switch to the hydraulic cylinder oil passages 6a, 6b.
The positional relationship is reversed, and the hydraulic cylinder oil passage 6a becomes the high pressure side, and the hydraulic cylinder oil passage 6b becomes the low pressure side. Therefore, the hydraulic cylinder oil passage 6 on the high pressure side
The pressure oil from a is supplied to the oil path switching logic valve 7b,
7f, the pressure oil is supplied to the base chamber 10b of the hydraulic cylinder 2b and the base chamber 9b of the hydraulic cylinder 2a, and at the same time, the pressure oil is pushed out from the tip chamber 10a of the hydraulic cylinder 2b and the tip chamber 9a of the hydraulic cylinder 2a. The oil flows back to the low-pressure side hydraulic cylinder oil passage 6b via the logic valves 7e and 7d, and both hydraulic cylinders 2a and 2b are expanded at the same time.

Although the embodiments of the drive control device for a concrete pump according to the present invention have been described in detail above, the present invention is not limited to the above embodiments, and the present invention does not depart from the scope of the claims. , it is possible to make various minor design changes.

For example, four hydraulic cylinder logic valves 3a to 3d that switch the positional relationship between the hydraulic cylinder oil passages 6a and 6b, and four valve logic valves 5 that switch the driving direction of the valve cylinders 4a and 4b.
A to 5d can each be replaced with a 3-position switching valve.

Furthermore, the pilot oil passages 13a, 13b, 17a, 17b and the pilot switching valves 14a, 14b for sequentially controlling the hydraulic cylinders 2a, 2b and the valve cylinders 4a, 4b can be replaced with solenoid valves that can be switched via limit switches. It is possible.

C Effect of the Invention According to the first feature of the drive control device for the concrete pump of the present invention described above, the high-pressure oil passage and the low-pressure oil passage that connect the hydraulic pump and the tank, and the base chamber and tip chamber of the pair of hydraulic cylinders. Six logic valves are installed in between, and these logic valves are controlled by two 3-position switching valves, so switching between low pressure large capacity mode, high pressure small capacity mode, draw mode, and extrusion mode can be done by changing the piping. It is possible to do this automatically without having to do it.

According to the second feature of the present invention, the logic valve and the three-position switching valve are installed in the head cover, rod cover, and main block of the concrete pump, making it possible to make the entire device compact.

[Brief explanation of the drawing]

Fig. 1 is a hydraulic circuit diagram of an embodiment of the drive control device for a concrete pump according to the present invention;
Figures a and 2b are diagrams showing the installation positions of each valve for mode switching, Figure 3 is a relay circuit diagram for controlling the solenoid valve, and Figure 4 is an explanatory diagram of mode switching in a conventional concrete pump. . 2a, 2b...Hydraulic cylinder, 6a, 6b...Oil passage for hydraulic cylinder (oil passage), 7a-7f...Logic valve for oil passage switching (logic valve), 9a, 1
0a... Tip chamber, 9b, 10b... Base chamber, 16a,
16b...First and second sub solenoid valves (3-position switching valve), 21...Head cover, 22...Rod cover, 23...Main block, P...Hydraulic pump, T
…tank.

Claims (1)

[Claims] 1. A concrete pump in which pistons in a pair of pump cylinders connected to one discharge pipe via a valve are reciprocated by a pair of corresponding hydraulic cylinders; Hydraulic pump P and tank T One of the two oil passages 6a, 6b connected to the eleventh hydraulic cylinder 2 is connected to the eleventh hydraulic cylinder 2 via the first and second logic valves 7a, 7b.
The other of the oil passages 6a and 6b is connected to the tip chamber 10a and the base chamber of the second hydraulic cylinder 2b via third and fourth logic valves 7c and 7d. 10b, and further communicates with the first and second hydraulic cylinders 2a, 2.
b's tip chambers 9a, 10a and base chambers 9b, 1
0b to the fifth and sixth logic valves 7e,
7f, these first to sixth logic valves 7a, 7f are connected to two three-position switching valves 16.
a, 16b, the front chambers 9 of the first and second hydraulic cylinders 2a, 2b are opened and closed.
A drive control device for a concrete pump, characterized in that it selectively communicates and shuts off communication between a and 10a, base chambers 9b and 10b, and two oil passages 6a and 6b. 2 Tip chambers 9 of the pair of hydraulic cylinders 2a and 2b
The fifth logic valve 7e is installed in the rod cover 22 that covers the rods 10a and 10a, and the main block 2 disposed on the upper part of the rod cover 22.
The first to fourth logic valves 7a, 7d and two three-position switching valves 16a, 16b are installed in the head cover 21 that covers the base chambers 9b, 10b of the pair of hydraulic cylinders 2a, 2b. 2. The drive control device for a concrete pump according to claim 1, characterized in that a sixth logic valve 7f is installed.