JPS6214387Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] This invention relates to a concrete pump that is optimal for use in feeding fresh concrete.

[Prior Art] A concrete pump has a hopper into which fresh concrete is introduced, and a suction/discharge port connected to the bottom of the hopper, and concrete pistons operated in opposite phases by hydraulic cylinders pump the fresh concrete in the hopper. Two concrete cylinders that suck and discharge alternately, and a hopper that is connected to the suction and discharge port of the concrete cylinder on the discharge operation side in synchronization with the operation of the concrete piston, and feeds the fresh concrete discharged from the concrete cylinder to the discharge pipe side. There is a type that has a swing tube as a flow path switching valve inside.

Usually, the drive hydraulic circuit for the hydraulic cylinders D ₁ and D ₂ in this type of concrete pump is constructed as shown in FIG. i.e. hydraulic cylinder
D ₁ , D ₂ cylinder head side and piston DP ₁ ,
Hydraulic oil (hereinafter referred to as closed oil) is stored between the hydraulic cylinders D _{1 and} DP ₂ , respectively.
Both ports on the head side of _D2 are connected. A hydraulic pump _P1 for closing oil replenishment and a closing oil replenishment valve V are connected to both ports on the head side. In addition, the rod-side ports of the hydraulic cylinders D ₁ and D ₂ are connected, and a main hydraulic pump P ₂ and its auxiliary hydraulic pressure P ₃ that supply high-pressure oil are connected to these ports via a switching valve T. concrete cylinder ₁ , concrete piston CP ₁ of C ₂ ,
CP ₂ is configured to be delivered alternately to the intake and exhaust ports H ₁ and H ₂ of the concrete cylinders C ₁ and C ₂ by switching the switching valve T. When the feeding work of fresh concrete is completed, the concrete cylinders C ₁ and C ₂ are arranged such that one concrete piston CP ₁ is placed at the inner bottom of the concrete cylinder C ₁ and the other concrete piston CP ₂ is placed at the suction/discharge port H ₂ side. It is designed to stop in the position.

[Problem to be solved by the invention] By the way, when the feeding work of fresh concrete is completed, it is necessary to wash out the fresh concrete remaining in the concrete cylinder _C1 before it hardens. ₁ has a connection opening at the bottom of the hopper as mentioned above,
In addition, the concrete piston CP ₁ of the concrete cylinder C ₁ is a concrete cylinder C 1 as described above.
Because they are located at the inner bottom of C ₁ , it is difficult to clean the concrete cylinder C ₁ and concrete piston CP ₁ , resulting in some parts being left unwashed due to oversight.
There is a risk that unwashed fresh concrete may harden inside the concrete cylinder _C1 . Therefore, in the past, when the feeding work was completed, the oil replenishment valve V was closed.
, and inject oil O ₁ into the head side of the hydraulic cylinder D ₁ from the hydraulic pump P ₁ for oil replenishment, and forcibly feed the concrete piston CP ₁ to the suction/discharge port H ₁ to remove the fresh concrete. The concrete piston CP ₁ was cleaned while preventing any residue from being washed. Therefore, a hydraulic pump for replenishing closed oil must be operated during cleaning operations, which is disadvantageous in that cleaning operations become troublesome. In addition, the high pressure oil of the main hydraulic pump P ₂ is applied to the piston rod side of the pistons DP ₁ and DP ₂ of the hydraulic cylinders D ₁ and D ₂ , but the pressure receiving area on the rod side of the piston is on the opposite side. Since the pressure receiving area on the head side is smaller by the area of the rod where the operating pressure is canceled, the drive operation efficiency of pistons DP ₁ and DP ₂ is poor, causing problems such as inability to feed fresh concrete efficiently. Ta.

[Purpose of the invention] This invention was created in view of the above points, and this invention is a method of sucking and discharging each concrete piston together without using a hydraulic pump for replenishing oil when cleaning a concrete cylinder. It is an object of the present invention to provide a concrete pump that can feed fresh concrete quickly and efficiently when feeding fresh concrete.

(Example) This invention will be explained below with reference to an illustrated example.

1 to 3, numeral 1 in the figures indicates a hopper of a concrete pump according to this invention, and this hopper 1 includes a front wall 1a, left and right side walls 1b,
It has a box shape surrounded by a rear wall 1b, a rear wall 1c, and a bottom plate 2, and a cleaning lid 2b for a discharge opening 2a is attached to the bottom plate 2.

The lower part of the front wall 1a is connected to the intake and exhaust ports 3a and 4a of the concrete cylinders 3 and 4, and the inner holes of the concrete cylinders 3 and 4 have concrete pistons 5 and 6 that reciprocate in opposite phases. is interpolated. In addition, the front wall 1a
A rotation operating shaft 9 of a swing tube 8, which will be described later, is horizontally supported by a bearing 7 attached to the center of the shaft. The flange 9a and rear end portion 9 of this rotation operation shaft 9
b is fixed from the front to the rear of the swing tube 8 as a flow path switching valve that switches the flow path in the hopper 1, and the narrow diameter portion 9c is fixed to the drive cylinder 10 attached to the front wall 1a. They are interlocked and connected via a drive arm 11. This swing tube 8 has a Z-shape with its axis deviated at the center.
The discharge end 8ca is rotatably connected to a discharge pipe 12 connected to the rear wall 1c, and the movable end 13 is connected to the suction and discharge ports 3a and 4a of the concrete cylinders 3 and 4. It's summery.

As a result, the movable end 13 of the swing tube 8 is swung in an arcuate trajectory with the rotation operation shaft 9 as the center of swing due to the expansion and contraction operation of the drive cylinder 10, and the moving end 13 of the swing tube 8 is swung in an arcuate trajectory with the rotation operation shaft 9 as the center of swing. The configuration is such that they are connected alternately. Moreover, hydraulic cylinders 14 and 15 are attached to the concrete cylinders 3 and 4 to reciprocate the concrete pistons 5 and 6 of the concrete cylinders 3 and 4. The stroke _L1 of the hydraulic cylinders 14, 15 is set to be equal to the stroke _L2 of the concrete cylinder, and the piston rods 16a, 17a of the hydraulic cylinders 14, 15 have pistons 5, 5 of the concrete cylinders 3, 4 at their tips. 6 is fixed. That is, the pistons 16, 1 of the hydraulic cylinders 14, 15
7 is cylinder head 1 of hydraulic cylinders 14 and 15
4a, 15a side, the concrete pistons 5, 6 of the concrete cylinders 3, 4 are located at the inner bottoms 3b, 4b of the concrete cylinders 3, 4, while the hydraulic cylinders 14, 15 are located at the inner bottoms 3b, 4b. The pistons 16 and 17 are
Rod covers 14b, 1 for hydraulic cylinders 14, 15
When the concrete pistons 5 and 6 are positioned at the stroke end on the 5b side, the concrete pistons 5 and 6 are positioned at the suction and discharge ports 3a and 4a of the concrete cylinders 3 and 4.

Next, the configuration of the drive hydraulic circuit for driving and operating the two hydraulic cylinders 14 and 15 will be explained with reference to FIG. 4.

Rod covers 14b for hydraulic cylinders 14 and 15,
Hydraulic oil (hereinafter referred to as closed oil CO) is stored in each cylinder on the 15b side.

Rod cover 14 of the hydraulic cylinders 14 and 15
The ports on the b and 15b sides are connected to each other,
If one piston 17 is driven toward the rod cover 15b, the oil in the hydraulic cylinder 15 is closed.
The CO is configured to move into the other hydraulic cylinder 14 and drive the piston 16 toward the cylinder head 14a. These ports are connected to a closed oil drain valve 18 for removing closed oil CO from the hydraulic cylinders 14 and 15, and an oil tank 19 therefor.
are connected via a conduit 20, and this conduit 2
In the middle of 0, there is a relief valve 21 and a valve 2.
2 are connected.

On the other hand, the ports on the cylinder head 14a, 15a side of the hydraulic cylinders 14, 15 are connected to pipe lines 23, 2.
4 are connected to each other, and these pipes 23, 2
4 has a 4-way solenoid operated switching valve 25.
is provided. Further, pipes 26 and 27 are connected to the switching valve 25, and a variable displacement main hydraulic pump 28 and a constant displacement auxiliary hydraulic pump 29 are connected to the pipe 26. A check valve 30 is provided between them. This main hydraulic pump 28 is connected to the hydraulic cylinders 14, 1
It supplies high pressure oil of, for example, about 300 kg/cm ² to the pump 5, and the discharge pressure can be adjusted continuously in response to load fluctuations, and the discharge pressure of the auxiliary hydraulic pump 29 is
It is smaller than the discharge pressure of the main hydraulic pump 28.

Further, a low pressure relief valve 31 set to a low pressure of, for example, about 12 kg/cm ² is connected to the pipe line 27, and the suction port side of this low pressure relief valve 31 is connected to the pipe line 27. . The suction port side of the auxiliary hydraulic pump 29 and the discharge port side of the low pressure relief valve 31 are connected to an oil tank 32.

The solenoid operation of the switching valve 25 is synchronized with the expansion and contraction operation of the drive cylinder 10, and the high pressure oil of the main hydraulic pump 28 is injected into the hydraulic cylinder side of the concrete cylinder to which the swing pipe 8 is connected. It is becoming.

That is, in this embodiment, both hydraulic cylinders 14, 1
A reed switch (not shown) is provided at 5, and the solenoid valve of the drive cylinder 10 that drives the swing tube 8 and the switching valve 25 are synchronized by the electric command of this reed switch. It is configured so that hydraulic pressure can be alternately supplied to the hydraulic piston side and the drive cylinder 10 in synchronized timing by switching operations.

The effect of the above configuration will be explained next.

First, to explain the operation of the drive hydraulic circuit during feeding work of fresh concrete K, the fresh concrete K is fed into the hopper 1, and the drive cylinder 10, main hydraulic pump 28, and auxiliary hydraulic pump 29
start. In addition, at this time, the closed oil drain valve 18
is closed and valve 22 is open. When the drive cylinder 10 is extended, the moving end 13 of the swing tube 8 is connected to the concrete cylinder 4 around the bearing 7. In sync with this,
The switching valve 25 is switched to the switching portion 25a side, and high pressure oil discharged from the main hydraulic pump 28 is injected into one hydraulic cylinder 15 via the switching valve 25. Then, the piston 17 reaches the stroke end on the rod cover 15b side, and the concrete piston 6 is paid out to the suction/discharge port 4a of the concrete cylinder 4. and closing the oil of the hydraulic cylinder 15.
Since CO is injected into the rod side of the other hydraulic cylinder 14 by the pressing force of the piston 17, the piston 16 of the hydraulic cylinder 14 reaches the stroke end on the cylinder head 14a side, and the oil returned from the hydraulic cylinder 14 is It returns to the main oil tank 32 via the low pressure relief valve 31. That is, the concrete piston 5 of the concrete cylinder 3
is operated to suck the fresh concrete K in the hopper 1, and the inside of the concrete cylinder 3 is filled with the fresh concrete K.

Next, when the drive cylinder 10 contracts, the moving end 13 of the swing tube 8 is connected to the concrete cylinder 3. In synchronization with this, the switching valve 25
The high pressure oil discharged from the main hydraulic pump 28 is injected into the other hydraulic cylinder 14 via the switching valve 25. Therefore piston 1
6 is from the cylinder head 14a to the rod cover 14b
The concrete piston 5 reaches the side stroke end, and the concrete piston 5 reaches the suction and discharge port 3a of the concrete cylinder 3
It is rolled out until. Then, the closed oil CO in the hydraulic cylinder 14 is re-circulated by the pressing force of the piston 16.
Since the oil is injected into the rod side of one hydraulic cylinder 15, the return oil in the hydraulic cylinder 15 is returned to the main oil tank 32, and the piston 17 of the hydraulic cylinder 15 reaches the stroke end on the cylinder head 15a side. That is, the concrete piston 6 of the concrete cylinder 4 operates to suck the ready-mixed concrete K in the hopper 1, so that the concrete cylinder 4 is filled with the ready-mixed concrete K, and the ready-mixed concrete K in the concrete cylinder 3 is The concrete piston 5 passes through the swing pipe 8 and is forced to the discharge pipe 12 side.

In this manner, the switching valve 25 and the electromagnetic valve of the drive cylinder 10 are switched at the same timing by an electric command from a reed switch (not shown), and high pressure oil of the main hydraulic pump 28 is supplied to the cylinder head 14a of the hydraulic cylinders 14 and 15. , 15a, the ready-mixed concrete K in the hopper 1 is discharged into the discharge pipe 12.
After that, it can be supplied to the pouring site. At this time, the high pressure oil of the main hydraulic pump 28 is injected into the cylinder heads 14a, 15a of the hydraulic cylinders 14, 15, and the pressure receiving area on the cylinder head side of the pistons 16, 17 is equal to the pressure receiving area on the rod side. In comparison, since the area of the rod is larger, the hydraulic cylinders 14 and 15 can be operated with a large force, and the concrete cylinders 3 and 4 can reliably suck and discharge the fresh concrete K in the hopper 1.

Note that this auxiliary hydraulic pump 29 is always operated, and the low pressure oil discharged from the pump 29 is supplied to the conduit 27 on the suction side of the main hydraulic pump 28. Further, the high pressure oil discharged from the main hydraulic pump 28 operates the hydraulic cylinder 14 or 15, returns to the pipe 27 via the switching valve 25, and is sucked into the main hydraulic pump 28 again. ing. In this hydraulic fluid circulation process,
Since there is a leak of hydraulic oil in the switching valve 25, main hydraulic pump 28, etc., the amount of oil returned is less than the amount of oil discharged due to the leakage, but this decrease is covered by the auxiliary oil. It will be replenished with the hydraulic oil discharged by the hydraulic pump 29. Furthermore, as described above, the hydraulic oil discharged from the main hydraulic pump 28 does not return to the oil tank 32, but is directly sucked into the main hydraulic pump 28, so there is no replacement of the hydraulic oil.
There is a risk that the oil temperature may rise or the hydraulic oil becomes contaminated. However, if the discharge amount of the auxiliary hydraulic pump 29 is made larger than the amount required to replenish the leakage amount described above, and the hydraulic oil from the oil tank 32 is forcibly mixed, the above-mentioned inconvenience can be prevented. can do. Further, the excess hydraulic oil supplied at this time is transferred to the oil tank 32 from the low pressure relief valve 31.
will return to. In order to effectively replenish the hydraulic oil and forcibly mix the hydraulic oil as described above, the set pressure of the low pressure relief valve 31 is maintained at a relatively low predetermined pressure (for example, 5 to 15 kg/cm ² ). It is necessary to keep it.

Next, after the feeding work of fresh concrete K is completed, the concrete cylinders 3 and 4 and the hopper 1 are
The operation of the drive hydraulic circuit when cleaning the inside of the machine will be explained.

When the feeding work of fresh concrete K is completed, the operation of the drive cylinder 10 and the main hydraulic pump 28 is stopped. In this state, the switching valve 25 is switched to the switching part 25c side, and as shown in FIG. 4, the concrete piston 5 of the concrete cylinder 3 is
The concrete piston 6 of the concrete cylinder 4 is fed out to the suction/discharge port 3a, and the concrete piston 6 of the concrete cylinder 4 is
It is located at the inner bottom portion 4b. As mentioned above, since low pressure is already applied to the piston 17 of the hydraulic cylinder 15 from the auxiliary hydraulic pump 29, the valve 22 is closed and the closed oil drain valve 1 is closed.
By opening 8, the oil in the hydraulic cylinder 15 is closed.
The CO is discharged into the oil tank 19 through the pipe 20, and the piston 17 reaches the stroke end on the rod cover 15b side. That is, the fresh concrete K remaining in the concrete cylinder 4 is discharged, and the concrete cylinders 3 and 4
The concrete pistons 5 and 6 are both inlet and outlet ports 3.
It will be in a state where it is drawn out to a, 4a. and the fifth
As shown in the figure, the cleaning lid 2b of the hopper 1 is opened to discharge the remaining ready-mixed concrete, and both concrete pistons 5 and 6 can be easily washed with water using a cleaning tool, so that the remaining ready-mixed concrete remains unwashed. There is no fear at all.

In addition, contrary to the above, the concrete piston 5 of the concrete cylinder 3 is attached to the inner bottom part 3b of the concrete cylinder 3, and the concrete piston 6 of the concrete cylinder 4 is attached to the inner bottom part 3b of the concrete cylinder 3.
Even if both hydraulic cylinders 14 and 15 are stopped while they are located at the suction and discharge ports 4a of the auxiliary hydraulic pump 2,
The concrete pistons 5 and 6 are both delivered to the suction and discharge ports 3a and 4a due to the low pressure at 9.

[Effects of the invention] As explained above, according to this invention, the rod side ports of each hydraulic cylinder are connected, and at least a closed oil drain valve and an oil tank are connected to these ports. At the same time, a main hydraulic pump that alternately supplies high-pressure oil to the head side port of each hydraulic cylinder at least in synchronization with the switching operation of the flow path switching valve, and a main hydraulic pump that is connected to this main hydraulic pump. A fixed displacement auxiliary hydraulic pump is connected to supply low pressure oil to the main hydraulic pump in accordance with the discharge output of the concrete cylinder, and also to appropriately supply low pressure oil to the hydraulic cylinder of the concrete cylinder on the side where the suction is stopped. Therefore, when cleaning concrete, by simply opening the closed oil drain valve, the closed oil from the hydraulic cylinder on the side where the suction is stopped can be drained, and each concrete piston can be fed out to the suction/discharge port. In addition to being effective in cleaning the concrete cylinder easily, the high-pressure oil from the main hydraulic pump that feeds the fresh concrete can be injected into the cylinder head side of the piston, which has a large pressure-receiving area, allowing the fresh concrete to be fed quickly and efficiently. Therefore, there is an effect that the cleaning workability and the feeding workability of the concrete pump can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the concrete pump according to this invention, FIG. 2 is a front view of the concrete pump taken along the - line in FIG. 1, and FIG. 3 is a front view taken along the - line in FIG. 4 is a cross-sectional view of the concrete pump, FIG. 4 is a driving hydraulic circuit diagram of a hydraulic cylinder, FIG. 5 is an explanatory diagram showing a state in which the concrete piston of the delivered concrete cylinder is being cleaned, and FIG. 6 is a conventional hydraulic circuit diagram. It is a drive hydraulic circuit diagram of a cylinder. 3, 4... Concrete cylinder, 5, 6...
Concrete piston, 14, 15... Hydraulic cylinder, 16, 17... Piston, 18... Closed oil drain valve, 28... Variable displacement main hydraulic pump, 29... Fixed displacement auxiliary hydraulic pump.

Claims (1)

[Claims for Utility Model Registration] A pair of concrete cylinders that are alternately sucked and discharged by a pair of hydraulic cylinders that operate in opposite phases are connected to each other at the bottom of the hopper, and the above-mentioned concrete cylinders are connected to each other at the bottom of the hopper. In concrete pumps that are equipped with flow path switching valves that are alternately connected to the concrete cylinders to switch the flow path in the hopper, the ports on the rod side of each of the hydraulic cylinders mentioned above are connected, and there are A closed oil drain valve and an oil tank are connected to each cylinder, and the main hydraulic oil supply alternately supplies high-pressure oil to the head side port of each hydraulic cylinder at least in synchronization with the switching operation of the flow path switching valve. a pump, which is connected to the main hydraulic pump and supplies low pressure oil to the main hydraulic pump in accordance with the discharge output of the main hydraulic pump;
A concrete pump characterized in that a fixed displacement auxiliary hydraulic pump is connected to a hydraulic cylinder of a concrete cylinder in a suction stopped state to appropriately supply low pressure oil.