JP4744205B2 - Concrete pump blockage prevention device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a concrete pump blockage prevention device used to prevent blockage of a concrete pump that alternately sucks and discharges concrete in a hopper.

A concrete pump in which concrete in a hopper is alternately sucked and discharged by two concrete pumping cylinders is conventionally known. Among them, a swing valve type concrete pump in which a swing pipe housed in a hopper is swung left and right as a suction discharge valve for switching suction and discharge is configured as shown in FIG. There are things.

That is, the oscillating pipe 1 is placed in a hopper 1 in which two suction / discharge ports 2 are provided side by side at the lower part of the front surface.
3 is swingably accommodated, and two concrete pumping cylinders 3 and 4 are arranged in parallel with and communicated with the two suction and discharge ports 2. 4 is connected to two main hydraulic cylinders 6 and 7 through a cleaning chamber 5. The concrete pumping pistons 8 and 9 housed in the concrete pumping cylinders 3 and 4 and the main hydraulic pistons 10 and 11 housed in the main hydraulic cylinders 6 and 7 are each one piston rod 12.
The main hydraulic pistons 10 and 11 are alternately advanced and retracted alternately, whereby the concrete pressure-feeding pistons 8 and 9 are alternately advanced and retracted, and the concrete pressure-feeding cylinders 3 and 4 are alternately When the concrete pumping cylinder 3 or 4 that sucks the concrete on the suction side is switched to the discharge side, the concrete 15 in the concrete pumping cylinder is moved to the swing pipe 13. , Transport pipe 1
4 is used for pressure feeding.

Furthermore, a hydraulic pump 16 and a tank 17 are connected to the two main hydraulic cylinders 6 and 7 in the concrete pump having the above-described configuration via a pressure oil supply / discharge line 18 provided with an electromagnetic four-way valve 19 on the way. The pressure sensor 20 is provided in the supply side line portion 18a of the pressure oil supply / discharge line 18, the pressure sensor 20 is connected to the controller 21, and the electromagnetic four-way valve 19 is in response to a command from the controller 21. Is switched to supply or discharge pressure oil to the main hydraulic cylinder 6 or 7. Therefore, when the concrete is blocked in the transport pipe 14, the pressure of the supply side line portion 18a of the pressure oil supply / discharge line 18 rises. When the increased pressure reaches a certain value, the controller 21 determines that an abnormality has occurred. The electromagnetic four-way valve 19 is switched by
The concrete pump is operated in reverse to release the blockage.

Further, in the concrete pump having the above configuration, when the concrete pump is operated in reverse, if there is a rising portion of the transport pipe 14 and there is a height difference, the transport pipe 14 is caused to flow backward.
Some of them have been designed to prevent a large impact force from acting on the main hydraulic cylinder 6 or 7, hydraulic equipment, etc., by applying a back-back force due to the difference in height on the inner concrete. It has been proposed (see, for example, Patent Document 1).

In addition, a method of releasing the blockage has been proposed in the past even with a squeeze concrete pump which is a concrete pump different from the above.

FIG. 6 shows an example of this. A hydraulic motor 22 for pumping concrete from the suction side to the discharge side while pressing the pumping tube having one end connected to the hopper as the rotating body rotates. The pressure oil supply line 25 on the discharge side of the hydraulic pump 24 is connected via the electromagnetic switching valve 23 for forward and reverse switching, and the pressure oil return line 26 is connected to the tank 27, and the solenoid of the electromagnetic switching valve 23 is connected. SOL. 1 or SOL. Port a for forward rotation by exciting 2
Alternatively, by switching to the reverse port b, the hydraulic motor 24 can be rotated forward and reverse, and a pressure switch PS is provided in the pressure oil supply line 25. The hydraulic motor 28 for driving the stirring device in the hopper is connected with a pressure oil supply line 31 on the discharge side of the hydraulic pump 30 via an electromagnetic switching valve 29 for forward and reverse switching, and the pressure oil The return line 32 is connected to the tank 27, and the solenoid SOL. 3 or SOL. 4 is excited and switched to the forward rotation port a or the reverse rotation port b.
Can be operated forward or reverse. As a result, when the pumping tube is blocked during the forward rotation operation and the pumping tube cannot be forward-fed in the forward direction, the pressure switch PS is activated to detect an abnormality and the electromagnetic switching valves 23 and 29 are switched. Thus, the operation is switched to the reverse operation to release the blockage (see, for example, Patent Document 2).

Japanese Patent No. 3569834 Japanese Patent No. 3172885

However, what is described in Patent Document 1 is a normal state in which the main hydraulic pistons 10 or 11 in the two main hydraulic cylinders 6 or 7 are alternately advanced and retracted to pump concrete.
When the pressure of the hydraulic oil supplied to the main hydraulic cylinder 6 or 7 rises due to the blockage of the concrete, the reverse rotation is automatically performed based on the signal from the pressure sensor 20, and the patent In the document 2, the pressure of the pressure oil supplied to the hydraulic motor 22 when the concrete in the pumping tube is normally driven by driving the hydraulic motor 22 for pumping the concrete and the concrete is blocked. As the pressure rises, the reverse rotation operation is automatically performed based on the signal of the pressure switch PS. In any case, the pressure at the time of starting the reverse rotation is such that the load at the time of pumping is the hardness of the concrete or It is constant without taking into account fluctuations due to the length, gradient, etc. of the transport pipe. Therefore, the load may vary when the concrete is normally pumped due to the above factors.For example, when the load at normal time is high, the pressure at which the concrete is pumped is high even though it is normal. If the load rises according to the load, there is a risk that the reverse operation will occur even though the concrete is not clogged, and conversely, if the normal load is low, the concrete will clog even if the concrete is clogged. Since the pressure for pumping does not increase, the start of reverse rotation operation is delayed, and there is a possibility that the blockage cannot be released.

Therefore, the present invention adjusts the reverse rotation start pressure in accordance with the load fluctuation even when the normal load fluctuates due to the hardness of the concrete, the length of the pipe, the gradient, etc. It is an object of the present invention to provide an optimal occlusion prevention device adapted to the above.

In order to solve the above problems, the present invention provides a main pressure sensor that detects pressure when normally pumping concrete and a main pressure sensor that switches between supply and discharge of pressure oil to the main hydraulic cylinder when pumping concrete normally. A four-way valve, a first electromagnetic switching valve and a second electromagnetic switching valve for switching to the reverse operation by switching the main four-way valve while pumping concrete, and switching by a pilot pressure from the first electromagnetic switching valve And a boost valve that causes the pilot pressure to act on the main four-way valve via the second electromagnetic switching valve , and inputs a pressure signal detected by the main pressure sensor, It has the function to memorize the maximum pressure when pumping normally, and also set the reverse rotation start pressure so that the pressure during concrete pumping becomes equal to or exceeds the set pressure for reverse rotation start That a comprises a controller having a function of outputting a reverse rotation instruction, the reverse command from the controller is output, switching the first electromagnetic switching valve and the second electromagnetic switching valve Rutotomoni, second from the boost valve The main four-way valve is switched by a pilot pressure acting on the main four-way valve via the electromagnetic switching valve, and the reverse operation is performed.

Specifically, in the above configuration, the reverse rotation start pressure is set manually, or the reverse rotation start pressure is automatically set based on the stored pressure by storing the maximum pressure when the concrete is being pumped normally. Then, set the set pressure on the controller.

In the above configuration, when the concrete is normally pumped, the solenoid of the solenoid valve for the main relief valve is ON, and the solenoids of the first solenoid switch valve and the second solenoid switch valve that switch to reverse operation are OFF. And when a reverse rotation command is output from the controller, the first electromagnetic switching valve and the solenoid of the second electromagnetic switching valve are configured to have an electric circuit that is turned on. If the pressure does not drop even if a reverse rotation command is output, a function is provided to output an abnormal output. When the abnormal output is output, the solenoid of the solenoid valve for the main relief valve, the first electromagnetic for switching to the reverse operation with the switching valve and the solenoid of the second electromagnetic switching valve in the OFF to stop the operation of the concrete pump, a configuration provided with an electric circuit which is to inform the abnormality So as to pressure.

Furthermore, the maximum pressure during normal pumping that is stored in the controller in each of the above-described structures is set to match the fluctuation of the load such as the composition of the pumped concrete, the length of the transport pipe, and the gradient.

According to the concrete pump blockage prevention device of the present invention,
(1) A main pressure sensor that detects the pressure when normally pumping concrete, a main four-way valve that switches the supply and discharge of pressurized oil to and from the main hydraulic cylinder when normally pumping concrete, and while pumping concrete The first electromagnetic switching valve and the second electromagnetic switching valve for switching the main four-way valve to switch to reverse operation, and the pilot pressure from the first electromagnetic switching valve is switched by the pilot pressure from the second electromagnetic switching valve. A boost valve that operates on the main four-way valve via a switching valve , and inputs a pressure signal detected by the main pressure sensor, and at the maximum when the concrete is normally pumped It has a function to memorize the pressure, and further sets a reverse rotation start pressure, and outputs a reverse rotation command when the pressure during concrete pumping becomes equal to or exceeds the set pressure for reverse rotation start. To a controller, the reverse command from the controller is output, the first electromagnetic switching the switching valve and the second electromagnetic switching valve Rutotomoni mainly four-way valve through a second electromagnetic switching valve from the boost valve The main four-way valve is switched with the pilot pressure acting on the engine so that it can be operated in reverse, and the reverse start pressure is set manually, or the reverse start pressure is being pumped normally. The maximum pressure is stored and automatically set based on the stored pressure, and the set pressure is set in the controller, so even when the reverse rotation start pressure is set manually in advance, Even when set, when the pressure during driving exceeds a preset reverse rotation start pressure, a reverse rotation command is automatically output from the controller to perform reverse operation and prevent blockage. Thereby, efficient placement can be performed.
(2) In the above configuration, when the concrete is normally pumped, the solenoid of the main relief valve solenoid valve is ON, and the first solenoid switching valve and the second solenoid switching valve that switch to reverse operation are OFF. And when a reverse rotation command is output from the controller, the first electromagnetic switching valve and the solenoid of the second electromagnetic switching valve are configured to be turned on, or the controller If the pressure does not drop even if the reverse rotation command is output, a function for outputting an abnormal output is provided. When the abnormal output is output, the solenoid of the solenoid valve for the main relief valve is switched to the first operation for switching to the reverse operation . the solenoid of the electromagnetic switching valve and the second electromagnetic switching valve stops the operation of the concrete pump is OFF, the with electrical circuits to inform the abnormal configuration Thus, when the reverse rotation command is output from the controller, the reverse rotation can be surely performed, and when the abnormal output is output, the operation can be stopped reliably and the abnormality is notified. The burden can be reduced, and it is possible to perform placement that does not cause blockage even by non-experts.
(3) Since the reverse rotation start pressure is set in accordance with the pumped material and the placement site, such as the composition of the pumped concrete, the length of the pipe, and the gradient, the optimal blockage prevention device can be obtained.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

FIG. 1 and FIG. 2 show an example of a hydraulic circuit of a concrete pump blockage prevention apparatus according to the present invention applied to a rocking valve type concrete pump in the same manner as the concrete pump shown in FIG. 5 as an embodiment of the present invention. The two concrete pumping cylinders 3, shown in FIG.
The piston rods 12 respectively connected to the pistons of two concrete cylinders (not shown) corresponding to 4 are slidably accommodated in two main hydraulic cylinders 6 and 7 arranged in parallel. An oil pump 16 and a tank 17 are connected to the main hydraulic cylinders 6 and 7 integrally with the hydraulic pistons 10 and 11, and a pressure oil supply pipe 34 and a pressure oil discharge pipe 35 each having a main four-way valve 33 are provided on the way. By connecting the main four-way valve 33, pressure oil is alternately supplied to and discharged from the two main hydraulic cylinders 6 or 7.

By supplying and discharging the pressure oil, the two main hydraulic cylinders 6 and 7 are expanded and contracted alternately, and the main hydraulic piston 1
The concrete sucked into a concrete pumping cylinder (not shown) is pumped by advancing and retreating 0 and 11, but at this time, the rocking pipe in the hopper is swung left and right to move the concrete. A valve drive hydraulic pump 38 and a tank 1 are connected to valve drive cylinders 36 and 37 for switching suction and discharge ports communicating with a concrete pressure feed cylinder on the pressure feed side.
7 is connected via a pressure oil supply pipe 40 having a valve four-way valve 39 and a pressure oil discharge pipe 41 on the way, and by switching the valve four-way valve 39, the pressure oil from the valve drive hydraulic pump 38 is supplied with pressure oil. By alternately supplying from the pipe 40 to the valve drive cylinder 36 or 37 through the valve four-way valve 39, the swing pipe is swung left and right in the hopper by the alternate expansion and contraction operation of the valve drive cylinder 36 or 37. Like that.

Further, a main pressure sensor 42 and a main oil pressure gauge 43 are provided in the middle of the pressure oil supply pipe 34 to the two main hydraulic cylinders 6 or 7, and the pressure oil supply pipe 34 and the pressure oil discharge pipe 35 are connected to each other. In the meantime, a main relief valve 44 is provided and a main relief valve electromagnetic valve 45 is provided. When the pressure oil is supplied to the main hydraulic cylinder 6 or 7 and the concrete is being pumped, the main relief valve is used. Solenoid valve 45
Solenoid SOL. 1 is excited so that the main relief valve 44 is deactivated.
In addition, a pilot switching valve 47 provided with a spool tip 46 protruding into the cylinder is provided at the stroke end portion on the rod side pressure chambers 6a, 7a side of the two main hydraulic cylinders 6, 7.
A pilot line 48 connected in the middle of the pressure oil supply pipe 40 for supplying pressure oil from the valve drive hydraulic pump 38 is boosted via the pilot switching valves 47 and the reverse electromagnetic switching valve 49 of the main hydraulic cylinders 6 and 7. Connected to the valve 50, the pilot pressure is alternately applied to both ends of the boost valve 50 by switching the two pilot switching valves 47 alternately so that the boost valve 50 is switched. Furthermore, a pilot line 51 is provided for switching the main four-way valve 33 by switching the boost valve 50 so that the pilot pressure alternately acts on both sides of the main four-way valve 33, and is branched from the pilot line 51. The valve drive cylinder 3
A pilot line 52 for applying a pilot pressure to the four-way valve 39 for switching between 6 and 37 is provided, and a reverse electromagnetic switching valve 53 is provided in the middle of the pilot line 52.

The reverse electromagnetic switching valve 53 provided in the pilot line 51 and the reverse electromagnetic switching valve 49 provided in the pilot line 48 are respectively connected to the solenoids SOL. 2, SOL. 3 is excited and switched to switch the main four-way valve 33 so that the reverse operation is started.

In addition, 54 is a sealing circuit, 55 is an unload valve incorporated between the pressure oil supply pipe 40 and the pressure oil discharge pipe 41 on the discharge side of the valve drive hydraulic pump 38, 56 is a livestock pressure device, and 57 is a valve hydraulic meter. is there.

FIG. 3 is an electric circuit diagram of the concrete pump blockage prevention apparatus according to the present invention. Although not shown in FIGS. 1 and 2, the controller 58 is provided, and the controller 58 is connected to a power source. The main pressure sensor 4 provided in the pressure oil supply pipe 34 shown in FIGS.
2 and a manual automatic changeover switch 59 for switching the setting of the reverse rotation start pressure to manual or automatic, and a normal pressure memory switch for memorizing the maximum pressure when the concrete is normally fed as normal pressure 60 in the controller 58, considering that the load at the time of concrete pumping fluctuates due to the hardness of the concrete to be placed, the length of the transport pipe or the gradient at the placement site, The main pressure sensor 42 detects the pressure when the concrete is normally pumped at the placement site and inputs the pressure to the controller 58. As a result, whether to set the reverse rotation start pressure manually or automatically is selected by the manual automatic changeover switch 59. When the automatic side is turned on by the switch 59, the normal pressure is fed normally. The controller 58 sets the maximum pressure when the
And display as a pressure monitor.

Further, the controller 58 has a reverse pressure adjustment circuit 61 for setting the reverse rotation start pressure in advance manually or automatically, and when the reverse rotation start pressure is set manually,
The pressure value arbitrarily set by the operator is set as the set pressure in the controller 58 and displayed on the reverse pressure display section. When the reverse rotation start pressure is automatically set, the normal pressure memory switch 60 is turned on and a certain ratio (set%) is set to the normal pressure (maximum pressure at normal time) stored in the controller 58. The multiplied value is set as the set pressure in the controller 58 and displayed on the reverse pressure display section.

The controller 58 also outputs a reverse rotation output relay X1 that outputs a reverse rotation command when the normal pressure input reaches or exceeds the set pressure for starting the reverse rotation in the manual or automatic mode.
And an abnormal output circuit B having an abnormal output relay X2 for notifying that an abnormality occurs when the pressure does not drop even when the reverse operation is performed.

Further, in the present invention, the operation command switch 62 commanded by the operator, the b-contact X2 of the above-mentioned abnormal output relay X2, the solenoid SOL. Of the main relief valve solenoid valve 45 shown in FIGS. 1 and a solenoid valve circuit C for the main relief valve connected in series with the solenoid SOL. 1 in parallel with the reverse output relay X1
The solenoid SOL.2 of the reverse electromagnetic switching valve 53 and the solenoid SOL.2 of the reverse electromagnetic switching valve 49 shown in FIGS. And a reverse buzzer circuit F formed by connecting the a contact X2 of the abnormal output relay X2 and the relay BZ of the abnormal buzzer.

As shown in FIG. 1, the pressure oil discharged from the hydraulic pump 16 passes through the pressure oil supply pipe 34 and the cross side port of the main four-way valve 33 as shown in FIG. Supplyed to the pressure chamber 6b, the main hydraulic piston 10 of the main hydraulic cylinder 6 is advanced. As a result, the concrete pressure-feeding piston in the concrete pressure-feeding cylinder connected to the main hydraulic piston 10 via the piston rod 12 is also advanced, and the concrete sucked into the concrete pressure-feeding cylinder is moved into the swing pipe. Discharged through
It will be pumped in the transport pipe. On the other hand, the pressure oil in the rod-side pressure chamber 6a of the hydraulic cylinder 6 is supplied to the rod-side pressure chamber 7a of the main hydraulic cylinder 7 on the opposite side via the sealing circuit 54, and the head-side pressure chamber of the main hydraulic cylinder 7 is supplied. The pressure oil 7b passes through the pressure oil discharge pipe 35 and is returned to the tank 17 so that the main hydraulic piston 11 in the main hydraulic cylinder 7 is retracted. Thereby, the concrete pressure-feeding piston in the concrete pressure-feeding cylinder connected to the main hydraulic piston 11 via the piston rod 12 is also retracted, and the concrete in the hopper is sucked into the concrete pressure-feeding cylinder. become.

When the main hydraulic piston 10 in one main hydraulic cylinder 6 reaches the forward stroke end in this way, the main hydraulic piston 10 pushes the spool tip 46 and the pilot switching valve 4.
7 is switched to the left in the figure, and the pilot line 48 is communicated with the left side of the boost valve 50 via the pilot switching valve 47 and the reverse electromagnetic switching valve 49.
The boost valve 50 is switched to the cross-side port by applying a pilot pressure to the left side. As a result, the pilot pressure from the pilot line 51 acts on the left side of the main four-way valve 33 in the figure via the reverse electromagnetic switching valve 53 to switch the main four-way valve 33 to the parallel port side, and at the same time, the boost As the valve 50 is switched, the pilot pressure in the pilot line 51 is applied to the parallel port side on the right side of the valve four-way valve 39 in the figure by the pilot line 52, and the valve four-way valve 39 is switched.

By switching the main four-way valve 33 and the valve four-way valve 39, the valve drive cylinders 36 and 37 are operated to swing the swing pipe 13 (see FIG. 5), thereby switching the concrete suction and discharge. Pressure oil from the hydraulic pump 16 is supplied to the head-side pressure chamber 7b of the main hydraulic cylinder 7 on the left side in the figure, and the main hydraulic piston 11 in the main hydraulic cylinder 7 is advanced. The main hydraulic piston 10 is moved backward. As a result, the concrete in the concrete pumping cylinder that has been on the suction side is discharged and pumped, and the concrete in the hopper is sucked into the concrete pumping cylinder on the discharge side.

Thereafter, the above-described operations are sequentially repeated, and the normal concrete pumping is performed. At this time, as described above, the load when the concrete is normally pumped by the concrete pump varies depending on the difference in hardness due to the mixing of the concrete, the length of the transport pipe, the gradient, etc.
The pressure of the pressure oil supplied to the head side pressure chamber 6b or 7b of the main hydraulic cylinder 6 or 7 through the pressure oil supply pipe 34 when the concrete is normally pumped in accordance with the load fluctuation is as follows:
The value is detected by the main pressure sensor 42 connected to the pressure oil supply pipe 34, and the value is input to the controller 58.

Next, the operator operates the manual automatic changeover switch 59 to select the reverse rotation start pressure between manual setting and automatic setting. That is, as shown in FIG. 4, first, when the setting of the reverse rotation start pressure is switched to the manual setting by the manual automatic changeover switch 59 before placing concrete, the operator arbitrarily sets the reverse rotation start pressure, for example, 25 Mpa. The set pressure is set as the reverse pressure in the controller 58. When the pressure for pumping concrete reaches or exceeds the set pressure during concrete placement, a controller 58 outputs a reverse rotation command, and automatically switches to reverse rotation for a certain time (or a fixed stroke). When the concrete pumping pressure drops below the reverse rotation start pressure, the normal operation is restored and the pumping is performed normally.

On the other hand, when the operator operates the manual automatic changeover switch 59 to switch the reverse rotation start pressure to the automatic setting, the normal pressure storage switch 60 is turned on after the concrete pouring starts.
N, and the controller 58 stores the maximum pressure in the state of normal pumping at this time as the normal pressure. When the normal pressure memory switch 60 is turned OFF after the maximum pressure in the normal state is stored in the controller 58, the normal pressure stored in the controller 58 is multiplied by a set percentage (for example, 120%) for starting reverse rotation. The value is set as the set pressure, and the set pressure is set as the reverse pressure in the controller 58. If the pressure for pumping concrete reaches or exceeds the set pressure for starting reverse rotation during concrete placement, a reverse rotation command is issued from the controller 58, and automatically switches to reverse rotation as in the case of manual operation described above. When reverse pressure operation is performed for a certain period of time and the pressure of concrete pumping falls below the reverse rotation start pressure, the operation is returned to the normal rotation operation so as to be normally pumped.

Further, in detail, during the concrete feeding and driving, the operation command switch 62 in FIG. 3 is turned on by the operation command from the operator, and the solenoid SOL. 1 is excited. On the other hand, since no reverse rotation command is output from the controller 58, the relay X1 of the reverse rotation output circuit A remains demagnetized. For this reason, the a contact X1 of the relay X1 is OFF, and the solenoids SOL. 2 and SOL. 3 remains demagnetized.

In such a state, when the main pressure sensor 42 detects that the concrete is blocked in the transport pipe and the pressure of the pressure oil in the pressure oil supply pipe 34 when the concrete is pumped is increased, the controller 58. , A manually set reverse pressure setting pressure (for example, 25 MPa) set in the controller 58 or an automatically set reverse pressure setting pressure (stored normal pressure × set% (for example, 120%) ))
When the pressure is equal to or greater than the set pressure, a reverse rotation command is output from the controller 58, and the relay X1 of the reverse rotation output circuit A in FIG. As a result, the contact a1 is turned ON, and the solenoids SOL. 2 and SOL. 3 are energized, and the reverse electromagnetic switching valves 49 and 53 are switched from the state shown in FIG. 1 as shown in FIG.

The solenoid SOL. 2 and SOL. 3 is an electromagnetic switching valve 49 for reversing the hydraulic circuit.
, 53 are switched to the parallel port side as shown in FIG. 2, and the pilot pressure of the pilot line 51 acts on the end of the main four-way valve 33 on the left side of the figure through the reverse electromagnetic switching valve 53 from the pilot line 51. 1 to switch the main four-way valve 33 to the parallel port side,
From the state of supplying concrete to the head side pressure chamber 6b of the right main hydraulic cylinder 6, the pressure oil is supplied to the head side pressure chamber 7b of the left main hydraulic cylinder 7 as shown in FIG. The main hydraulic piston 10 in the right main hydraulic cylinder 6 is automatically reversed so as to be retracted, and the concrete being pumped is sucked back.

After a certain period of time has elapsed or the main hydraulic cylinders 6 and 7 are operated in reverse by a fixed stroke,
When the pressure decreases, the output of the reverse rotation command from the controller 58 is turned off, so that the relay X1 of the reverse rotation output circuit A is demagnetized, and the contact a1 is turned off to turn the reverse electromagnetic switching valve 53.
49 solenoid SOL. 2, SOL. 3 is demagnetized. Thereby, the reverse electromagnetic switching valves 49 and 53 are returned to the state shown in FIG. 1 and returned to the normal operation.

In the above, when the abnormal pressure exceeding the set pressure of the reverse rotation start pressure does not drop even when the reverse operation is automatically switched, an abnormal output is output from the controller 58 and the relay X2 of the abnormal output circuit B is excited. The b contact X2 of the solenoid valve circuit C for the main relief valve is turned OFF, and the solenoid SOL. 1, SOL. 2, SOL. 3 is demagnetized, and the pressure oil is returned from the pressure oil supply pipe 34 to the tank 17 through the main relief valve 44, the operation of the concrete pump is stopped, and the a contact X2 of the relay X2 is turned ON to cause an abnormality. The buzzer is informed of the abnormality.

Also, when returning to normal operation after switching to reverse operation and releasing clogging, the pressure at the time of pumping rises again and automatically switches to reverse operation. Therefore, it is judged that the blockage cannot be released, and as in the case described above, the concrete pumping is stopped by an abnormal output, and an abnormal buzzer is notified.

The present invention is not limited to the above embodiment. For example, as a concrete pump, a concrete pump of a swing valve type is exemplified. However, pumping in a squeeze-type concrete pump as shown in FIG. When the concrete is blocked in the tube, set the reverse rotation start pressure when reversing the hydraulic motor for concrete pumping in the same way, and when the pressure during concrete pumping reaches or exceeds the set pressure for reverse rotation start Of course, it is possible to perform a reverse rotation operation by outputting a reverse rotation command, and other various modifications can be made without departing from the scope of the present invention.

It is a figure at the time of forward rotation operation which shows an example of the hydraulic circuit in one Embodiment of the blockage | blocking prevention apparatus of the concrete pump of this invention. FIG. 2 is a hydraulic circuit diagram when a reverse operation is performed from the normal rotation operation of FIG. 1. It is a figure which shows an example of the electric circuit figure in one Embodiment of the blockade prevention apparatus of the concrete pump of this invention. It is a figure which shows the control flow of the controller in the electric circuit shown in FIG. It is the schematic which shows an example made to cancel | release blockade of the conventional concrete pump. It is a hydraulic circuit diagram which shows the other example made to cancel | release obstruction | occlusion of the conventional concrete pump.

Explanation of symbols

34 Pressure Oil Supply Pipe 42 Main Pressure Sensor 44 Main Relief Valve 45 Main Relief Valve Solenoid Valve 49 Reverse Direction Solenoid Switching Valve (Electromagnetic Switching Valve)
53 Electromagnetic switching valve for reverse rotation (electromagnetic switching valve)
58 Controller SOL. 1 Solenoid SOL. 2 Solenoid SOL. 3 Solenoid

Claims (5)

The main square and the main pressure sensor for detecting a pressure, and a main four-way valve for switching the pressure oil supply and discharge of the main hydraulic cylinder when properly pumped concrete, the concrete during pumping upon successfully pumped concrete A first electromagnetic switching valve and a second electromagnetic switching valve for switching the valve to reverse operation, and a pilot pressure from the first electromagnetic switching valve that is switched by the pilot pressure from the first electromagnetic switching valve; A boost valve that acts on the main four-way valve via the pressure sensor, and inputs a pressure signal detected by the main pressure sensor and stores the maximum pressure when the concrete is normally pumped. Furthermore, it has a function to set a reverse rotation start pressure and to output a reverse rotation command when the pressure during concrete pumping becomes equal to or exceeds the set pressure for reverse rotation start. Comprising a controller, the reverse command from the controller is output, to the first electromagnetic switching the switching valve and the second electromagnetic switching valve Rutotomoni mainly four-way valve through a second electromagnetic switching valve from the boost valve An apparatus for preventing clogging of a concrete pump, characterized in that the main four-way valve is switched by a pilot pressure that is operated to perform reverse operation .   Set the reverse rotation start pressure manually, or store the maximum reverse pressure when the concrete is pumped normally and automatically set it based on the stored pressure, and set the set pressure in the controller The concrete pump blockage prevention device according to claim 1, wherein When the concrete is being pumped normally, the solenoid of the solenoid valve for the main relief valve is turned on, the solenoids of the first solenoid switching valve and the second solenoid switching valve for switching to reverse operation are turned off, and from the controller 3. The concrete pump blockage prevention device according to claim 1, further comprising an electric circuit in which the solenoids of the first electromagnetic switching valve and the second electromagnetic switching valve are turned on when a reverse rotation command is output. . Provide the controller with a function to output an abnormal output when the pressure does not drop even if a reverse rotation command is output, and when the abnormal output is output, the solenoid of the main relief valve solenoid valve is switched to reverse operation . The concrete pump according to claim 1, 2 or 3, further comprising an electric circuit configured to stop the operation of the concrete pump by turning off the solenoids of the first electromagnetic switching valve and the second electromagnetic switching valve and to notify the abnormality. Blockage prevention device.   The maximum pressure when normally pumped to be stored in the controller is adjusted to the load variation such as the composition of the pumped concrete, the length of the transport pipe, and the gradient. 4. Blocking prevention device for concrete pump according to 4.

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