JPH0130630Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a control device for a concrete pump.

An example of a conventional concrete pump is shown in FIG. 1, in which 1 and 2 are a pair of concrete cylinders, and concrete pistons 3 and 4 are fitted in a sealed and slidable manner. Rod 5,
6 to hydraulic pistons 9 and 10 which are slidably fitted in a pair of hydraulic cylinders 7 and 8 in an oil-tight manner. By supplying and discharging pressure oil to and from 7 and 8, the concrete pistons 3 and 4 alternately reciprocate within the concrete cylinders 1 and 2 in opposite directions. In the process in which the concrete piston 3 advances to the right and the concrete piston 4 retreats to the left, the hydraulic cylinder 14 for driving the discharge valve,
By supplying and discharging pressure oil to and from the supply valve 15, the discharge valve 16 is moved upward to communicate with the concrete cylinder 1 and the discharge pipe 17, and at the same time, the communication between the concrete cylinder 2 and the discharge pipe 17 is cut off. By supplying and discharging pressure oil to and from the driving hydraulic cylinders 18 and 19, the supply valve 20 is moved downward, cutting off the concrete cylinder 1 and the hopper, and communicating the concrete cylinder 2 and the hopper. Thus, concrete piston 3
As the concrete piston 4 moves forward to the right, the concrete in the concrete cylinder 1 is pushed out to the discharge pipe 17, and as the concrete piston 4 retreats to the left, the concrete piston 2 is pushed out from inside the hopper.
Inhale concrete inside. When the concrete pistons 3 and 4 reach their respective stroke ends,
The switching valve 12 is switched, and at the same time, the pressure oil to the hydraulic cylinders 14, 15 for driving the discharge valves and the hydraulic cylinders 18, 19 for driving the supply valves is switched, and concrete is sucked into the concrete cylinder 1 from the hopper and from the concrete cylinder 2. Concrete is discharged into the discharge pipe 17. By repeating the above steps, concrete is continuously discharged into the discharge pipe 17.

In the above concrete pump, when the reversing valve 11 is switched while concrete is being pumped to a high place,
Since a speed regulating valve is not installed in the return line 21, the concrete piston 3 or 4 is pushed by the concrete and collides with the stopper 22 at high speed, damaging the concrete pistons 3, 4 and the stopper 22, or causing a surge when stopped. It may cause pressure to adversely affect the concrete, or the discharge valve 16 or supply valve 2 may
It gives a shock to 0. Therefore, the operator inches the reversing valve 11 to prevent the concrete pistons 3 and 4 from colliding with the stopper 22, but this inching operation requires skill, and if the operator makes a mistake, the concrete pistons 3 and 4 It will collide with the stopper 22.

To deal with this, it has been proposed to install a solenoid valve 23 in the return line 21 that throttles the oil flow only when the rotation is reversed, as shown in Figure 2, but this increases pressure loss and is expensive. There was a problem with this.

The present invention has been proposed to address the above-mentioned problems, and its purpose is to automatically inching the reversing valve using an inexpensive electric circuit.

The gist of the present invention is to provide a concrete pump equipped with a hydraulic cylinder that reciprocates a concrete cylinder that sucks in and pumps concrete, and a reversing valve that operates the hydraulic cylinder in reverse. It is equipped with an electromagnetic solenoid that switches to reverse rotation, a selection switch that can select at least between a forward rotation contact and a reverse rotation contact, an inching switch, and a flickering relay, and when the inching switch is turned on, the selection switch selects the reverse rotation contact. The control device for a concrete pump is characterized in that the concrete pump is connected so that the electromagnetic solenoid is energized via the flicker relay when the concrete pump is running.

Since the present invention has the above configuration, the reversing valve can be easily and reliably inched regardless of the operator's skill level, and the concrete piston can be prevented from colliding with the stopper at high speed. Moreover, the electromagnetic solenoid
Since the reversing valve can be automatically inched by electrical means such as a selection switch, an inching switch, or a flicker relay, the cost is lower than that of conventional valves, and the operation is quick and reliable.

FIG. 3 shows an electrical circuit according to one embodiment of the present invention. 30 is a selection switch which can be selectively connected to its forward rotation F, stop S and reverse rotation R contacts. Note that the figure shows only the reverse rotation circuit, only the normal rotation circuit, and omits the normal rotation circuit. 31 is a reversing solenoid, and this solenoid 31 operates the reversing valve 11. 32 is an inching switch, 33 is a relay, 34 is a flickering relay, 33
-a is the A contact of relay 33, 33-b is relay 3
The B contact 34-a is a contact of the flicker relay 34. Note that the other configurations are similar to those shown in FIG.

During normal operation, the inching switch 32 is
When OFF, relay 33 is de-energized and its B contact 33-b remains closed. Selection switch 30
When the reverse contact R is applied, the reverse solenoid 31
is energized and the reversing valve 11 is switched, so the concrete pump performs reverse operation and the discharge pipe 17
The concrete inside is transported back into the hopper. When performing inching reversal when pumping concrete to a high place, etc., the inching switch 32 is turned on and the selection switch 30 is placed in its reversing contact R. Then, the relay 33 is energized, so the A contact 33-a of the relay 33 closes, and the B contact 33-a of the relay 33 closes.
b is open. Therefore, the reverse solenoid 31 is energized via the contact 34-a of the flicker relay 34. Flickering relay 34 is ON,
Since the contact 34-a is repeatedly turned OFF, the reversing solenoid 31 is continuously supplied with power, so the reversing valve 11 is also in an intermittent operation, that is, an inching state, and the concrete piston 3 is in a reversing operation while inching. Become.

In this way, since the concrete pistons 3 and 4 are inched, the concrete pistons 3 and 4 are not pushed by the concrete and collided with the stopper 22 at high speed during reverse rotation as in the conventional case.
Further, the reversing valve 11 can be easily inched regardless of the operator's skill level. In addition,
The flickering relay 34 can also be combined with a timer relay or the like to make the ON/OFF time variable.

[Brief explanation of the drawing]

1 and 2 are schematic hydraulic system diagrams of a conventional concrete pump, respectively, and FIG. 3 is an electrical circuit diagram according to an embodiment of the present invention. 1, 2... Concrete cylinder, 7, 8...
Hydraulic cylinder, 11...Reverse valve, 31...Electromagnetic solenoid, 30...Selection switch, F...Forward rotation contact, R...Reverse rotation contact, 34...Flicker relay.

Claims (1)

[Scope of utility model registration request] A concrete pump comprising a hydraulic cylinder that reciprocates a concrete cylinder that sucks in and pumps concrete, and a reversing valve that operates the hydraulic cylinder in reverse, comprising at least an electromagnetic solenoid that switches the reversing valve between normal rotation and reverse rotation. It is equipped with a selection switch that can select between a forward rotation contact and a reverse rotation contact, an inching switch, and a flicker relay, and when the inching switch is turned on and the selection switch selects the reverse rotation contact, a A control device for a concrete pump, characterized in that the concrete pump is connected so that the electromagnetic solenoid is energized.