JP2522808Y2 - Hydraulic circuit for driving concrete pump cleaning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a washing device driving hydraulic circuit for operating a washing device such as a water pump and a compressor in a concrete pump.

[Conventional technology]

Generally, in the concrete pump, when the work of sending the ready-mixed concrete from the hopper to the casting site via the transport pipe is completed, the ready-mixed concrete pump remains in the transport pipe and the hopper. In addition, a water pump or a compressor disclosed in, for example, Japanese Utility Model Application Laid-Open No. 61-125382 is provided for cleaning the inside of the transport pipe and the hopper.

As a power source for driving these water pumps and compressors, a hydraulic pump for an operation cylinder of a flow path switching valve of a concrete pump is commonly used, or a special hydraulic pump is separately provided. The operation cylinder of the above-mentioned flow path switching valve is connected to one of a pair of concrete transfer cylinders for sucking and discharging the ready-mixed concrete, which is connected to the transport pipe, and to another connection of the concrete transfer cylinder to the hopper. Are alternately enabled.

FIG. 4 shows a concrete pump having a flow path switching valve (oscillating pipe) in which a bent pipe is slidably provided in a hopper, and a hydraulic pump for a hydraulic cylinder for oscillating the oscillating pipe is shared. FIG. 4 is a hydraulic circuit diagram when the water pump cylinder is operated by pressing.

In the figure, 101 is a hopper for charging ready-mixed concrete, and 102 and 103 are pistons for the ready-mixed concrete in the hopper 101.
This is a pair of concrete transfer cylinders that perform suction and discharge by 102a and 103a.

104 is a swinging tube, which is provided in the hopper 101 and has one end 10
4a is connected to the transport pipe 105, the other end 104b is a free end, the swing pipe 104 is swung about one end 104a as a fulcrum, and the other end 104b is moved to the pair of concrete transfer cylinders 102, 10
Communicate alternately with 3. Reference numeral 106 denotes a hydraulic cylinder (swing cylinder) that swings the swing tube 104.

107 and 108 are a pair of hydraulic cylinders, each rod 1
07a and 108a are a pair of concrete transfer cylinders 102 and 103
Are connected to the pistons 102a, 103a in the
Move 103a forward and backward.

One end side working chambers 107b, 10 of a pair of hydraulic cylinders 107, 108
An electromagnetic directional control valve 111 is connected to 8b via a first conduit 109 and a second conduit 110, respectively.

Reference numeral 112 denotes a main pump, which is connected to the electromagnetic direction control valve 111 via a third line 113. A tank 114 is connected to the electromagnetic directional control valve 111 via a fourth pipe 115.

An electromagnetic directional control valve 118 is connected to both working chambers 106a and 106b of the swing cylinder 106 via a fifth conduit 116 and a sixth conduit 117, respectively.

The electromagnetic directional control valve 118 is a switching valve via a seventh pipe 119.
Connect to A port 120A of 120, B port 12 of switching valve 120
OB is connected to an electromagnetic directional control valve 122 via an eighth conduit 121. The operation of the electromagnetic direction control valve 122 causes the water pump cylinder 123 to reciprocate. An auxiliary pump 124 is connected to the switching valve 120.

Then, the switching valve 120 is switched to the side opposite to the one shown in the figure, and the auxiliary pump 124 is switched to the electromagnetic directional switching valve 122 through the pipe 121.
When the water pump cylinder 123 is driven to reciprocate by operating the electromagnetic direction switching valve 122 alternately to switch the flow direction, water is supplied from the water pump (not shown) into the transport pipe 105. After being discharged, the remaining ready-mixed concrete is discharged from the inside of the transport pipe 105 through the filling, and the inside of the transport pipe 105 is washed with water.

By operating the switching valve 120 to the state shown in the figure,
The operation of the electromagnetic directional control valves 111 and 118 causes the hydraulic cylinder
During the operation of moving the ready-mixed concrete into the transport pipe 105 by reciprocating the 107, 108 and the swing cylinder 106, the water pump cylinder 123 is stopped. When the switching valve 120 is operated to reciprocate the water pump cylinder 123, the swing cylinder 106 is stopped.

FIG. 5 is a hydraulic circuit diagram in a case where a water pump cylinder is operated by providing a special hydraulic valve separately from the hydraulic pump of the swing cylinder. Only parts different from FIG. 4 will be described. In FIG. 5, the same components as those in FIG. 4 are denoted by the same reference numerals.

In the figure, a water pump cylinder 123 is connected to a manual directional control valve 131 via an electromagnetic directional control valve 122, and this manual directional control valve 131 is connected to a special hydraulic pump 132 provided separately from the auxiliary pump 124. I have. One output port 131A of the manual directional control valve 131 has a blind cover, and the manual directional control valve 131
131 is used as a three-port switching valve.

133 is a hydraulic motor for rotating a compressor (not shown) used for cleaning the inside of the transport pipe 105 with air, and an output port 131A of the manual directional control valve 131 with a blind lid.
Can be connected selectively. The hydraulic motor 13
When rotating 3, the oil is not supplied to the water pump cylinder 123, and the water pump does not operate.

The operation of the electromagnetic direction control valve 122 causes the water pump cylinder 123 to reciprocate.

In this case, since the water pump cylinder 123 is reciprocated by the special hydraulic pump 132, the swing cylinder 106 is reciprocated by the auxiliary pump 124 at the same time, and the transport pipe 1 is moved by the water pump.
The inside of 05 and the inside of hopper 101 can be cleaned at the same time.

[Problem to be Solved by the Invention] However, in the former hydraulic circuit of the concrete pump (FIG. 4), although a special hydraulic pump is not required to operate the water pump cylinder 123, the water pump cylinder 123 Since only one of the swing cylinder 106 and the swing cylinder 106 is operated via the switching valve 120, when the water pump cylinder 123 is operated to clean the inside of the transport pipe 105, the swing cylinder 106 cannot be operated. However, there is a problem that the inside of the hopper 101 cannot be cleaned while the swing tube 104 is swinging.

On the other hand, the hydraulic circuit of the latter concrete pump (No. 5)
In the figure), the water pump cylinder 123 and the swing cylinder 106 operate simultaneously, and the inside of the transport pipe 105 and the hopper 101 can be washed at the same time. However, as a power source of the water pump cylinder 123 that operates the water pump, In addition to the hydraulic pump for the swing cylinder 106, a special hydraulic pump 132 is specially required, resulting in an increase in production cost.

Therefore, in order to solve the above-mentioned drawbacks of the hydraulic circuit, it is conceivable to branch the pipeline from the main circuit for the hydraulic cylinders 107 and 108 and supply oil to the water pump cylinder 123 from the pipeline to operate the hydraulic pump. Since the flow rate of the main circuit is generally large, even if a directional control valve is provided at the branch of the main circuit to divide the flow, a large directional control valve is required, which is not preferable.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to operate a cleaning device actuator for driving a water pump, a compressor, and the like without installing a new hydraulic pump. Cleans concrete pumps that can simultaneously clean the transport pipe and the inside of the hopper, and that can supply oil to the actuator for the cleaning device with a small directional switching valve even when the main circuit that operates the hydraulic cylinder is used as a hydraulic source. It is to provide a hydraulic circuit for driving the device.

[Means for solving the problem]

The present invention provides a hopper for charging ready-mixed concrete, a pair of concrete transfer cylinders for sucking and discharging the ready-mixed concrete in the hopper by a piston, and a pair of concrete transfer cylinders driven by a valve operating cylinder. Alternately communicate the transport pipe to one of the
A flow path switching valve for alternately performing a communication operation for communicating the other with the hopper and a communication operation in the opposite direction, a pair of hydraulic cylinders for moving forward and backward pistons in a pair of concrete transfer cylinders, and a pair of hydraulic cylinders A directional control valve connected to the one end side working chamber via a pipe, a main hydraulic pump connected to the directional control valve via a pipe, and switching of the directional control valve for a pair of hydraulic cylinders An electromagnetic direction control valve that switches the flow path of the pressure oil to a valve operating cylinder that operates the flow path switching valve such that the communication operation and the reverse communication operation are alternately performed in conjunction with the operation. And a cleaning device actuator for operating a cleaning device such as a water pump, in a pipeline connecting the main hydraulic pump and the directional control valve. And a switching valve provided in the branch pipe for supplying / cutting off the pressurized oil to the cleaning device actuator and the cleaning device actuator, and the cleaning device actuator are repeatedly operated. A cleaning device switching valve including an electromagnetic valve; a cleaning device power switch for opening and closing an electric circuit for driving the cleaning device switching valve; and a cleaning device power switch interlocked with the cleaning device power switch when the cleaning device actuator is operated. Means for lowering the number of revolutions of the engine for rotating the main hydraulic pump.

[Action]

In the present invention, when the cleaning device such as a water pump is operated, when the power switch for the cleaning device is switched, the rotation speed of the engine that rotates the main hydraulic pump is reduced, and the cleaning device switching valve is interlocked therewith. It will be in the open state and a small flow of hydraulic oil will flow from the main hydraulic pump to the branch line.
The cleaning device switching valve → the cleaning device actuator → the tank flows in this order, and the cleaning device actuator is driven.

Therefore, it is possible to simultaneously perform the cleaning of the transport pipe and the cleaning of the inside of the hopper by spraying the cleaning water from a water pump or the like operated by the cleaning device actuator.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 and 2 show a concrete pump according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a hopper for charging ready-mixed concrete, and reference numerals 2 and 3 denote the ready-mixed concrete in the hopper 1 with pistons 2a and 2a.
3a is a pair of concrete transfer cylinders that perform suction and discharge according to 3a.

Reference numeral 4 denotes an oscillating pipe as a flow path switching valve, which is provided in the hopper 1, one end 4a of which is connected to the transport pipe 5, the other end 4b is a free end, and the oscillating pipe 4 has one end 4a. The other end 4b is pivoted about the axis so as to alternately communicate the other end 4b to the pair of concrete transfer cylinders 2, 3.
Reference numeral 6 denotes a valve operating hydraulic cylinder (swing cylinder) that swings the swing pipe 4.

Reference numerals 7 and 8 denote a pair of hydraulic cylinders whose rods 7a,
8a is connected to the pistons 2a, 3a in the pair of concrete transfer cylinders 2, 3, and moves the pistons 2a, 3a forward and backward.

An electromagnetic directional control valve is connected to one end side working chambers 7b, 8b of the pair of hydraulic cylinders 7, 8 via a first pipe 9 and a second pipe 10, respectively.
11 are connected. The other end side working chambers of the hydraulic cylinders 7 and 8 communicate with each other through a pipeline 8c.

The electromagnetic directional control valve 11 has an A port 11A, a B port 11B, a P port 11C, and a T port 11D connected to the first pipe 9 and the second pipe 10, and has an electromagnetic valve 12 having solenoids 12a and 12b. ,
A pilot operation valve 13 that is operated by a pilot pressure from a solenoid valve 12 is incorporated.

Reference numeral 14 denotes a main hydraulic pump, which is connected to a P port 11C of the electromagnetic directional control valve 11 via a third conduit 15. Reference numeral 16 denotes a hydraulic oil tank, which is a T port of the electromagnetic directional control valve 11 through a fourth pipe 17.
Connected to 11D.

An electromagnetic directional control valve is connected to both working chambers 6a and 6b of the swing cylinder 6 via a fifth pipe 18 and a sixth pipe 19, respectively.
20 are connected.

The electromagnetic directional control valve 20 has an A port 20A, a B port 20B, a P port 20C, and a T port 20D connected to the fifth conduit 18 and the sixth conduit 19, and has an electromagnetic valve 21 having solenoids 21a and 21b. ,
A pilot operation valve 22 that operates by the pilot pressure from the solenoid valve 21 is built in.

An auxiliary hydraulic pump 23 is connected to a P port 20C of the electromagnetic directional control valve 20 via a seventh conduit 24. The T port 20D of the electromagnetic directional control valve 20 is connected to the hydraulic oil tank 1 through an eighth line 25.
Connected to 6.

The branch conduit 26 is connected to a middle portion 15A of the third conduit 15. The branch pipe 26 is provided with a water pump cylinder (actuator for cleaning device) 27 for operating a water pump (not shown) and a switching valve 28 for the water pump cylinder 27. That is, the switching valve 28 is interposed in the middle of the branch line 26, and the A port 28A of the switching valve 28 is operated by the one end of the water pump cylinder 27 through the cylinder side portion 26A of the branch line 26. The port 27B of the switching valve 28 is connected to a working chamber 27b at the other end of the water pump cylinder 27 via a cylinder-side portion 26B of the branch pipe 26. P port 28C of switching valve 28
Is connected to the branch line 26 via the pump-side portion 26C of the branch line 26.
T port 28D is connected to the tank side portion 26D of the branch line 26.
Is connected to the hydraulic oil tank 16. The switching valve 28 includes a solenoid valve 29 having solenoids 29a and 29b for reciprocatingly driving the water pump cylinder 27, a pilot operation valve 30 operated by pilot pressure from the solenoid valve 29, and a water pump cylinder. And a manual switching valve 31 for shutting off supply of oil to 27.

A blind cover is provided at the B port 31B of the manual switching valve 31, and the P port 31C of the manual switching valve 31 is connected to the P port 2 of the switching valve 28.
8C, the T port 31D of the manual switching circle 31 is in communication with the T port 28D of the switching valve 28.

In the pilot operation valve 30, the A port 30A communicates with the A port 28A of the switching valve 28, and the B port 30B communicates with the B port 28B of the switching valve 28. An oil passage 32A in the switching valve 28 connects the P port 30C of the pilot operation valve 30 to the A port 31A of the manual switching circle 31, and the oil passage 32A
32B makes the T port 30D of the pilot operation valve 30 communicate with the T port 28DS of the switching valve 28.

In the switching valve 28, 29d and 29f are solenoid valves 2
This is a pilot conduit for communicating the pilot valve 9 with the pilot operation valve 30. Reference numerals 29c and 29e denote pilot conduits for communicating the solenoid valve 29 with the oil passages 32A and 32B.

Then, a pressure control line 33 is provided at an intermediate portion 26E of the branch line 26.
A two-position electromagnetic directional control valve 34 is provided in the middle of the pressure control line 33, and a relief valve 35 for the main circuit and a relief valve 36 for the water pump circuit are interposed downstream thereof in parallel. I have.

In the drawing, LS ₁ denotes a proximity switch for detecting the movement stroke of the piston 3 a of the hydraulic cylinder 8, and LS ₂ denotes a proximity switch for detecting the movement stroke of the piston 2 a of the hydraulic cylinder 7.

Next, an electric circuit for driving the concrete pump will be described with reference to FIG.

As shown in the figure, the power supply side 37 includes thyristors SCR ₁ and SCR ₂
Of the thyristor SCR ₁ is connected to the anode of
The solenoid 38a is connected to the solenoid 12a of the electromagnetic directional control valve 11 via a contact 38a of the relay 38, and the solenoid 12a is connected to the a
It is connected to the power supply side 40 via the contact 39a. The cathode of the thyristor SCR _1, the power-side 40 via a resistor R ₆
Connected to one end of a contact 38d of a relay 38, and further connected to a solenoid 21b of the electromagnetic directional control valve 20.
And is connected to the power supply side 40 via. A contact of relay 38
The other end of 38d is connected to the solenoid 12b of the electromagnetic direction control valve 11.

On the other hand, the cathode of the thyristor SCR ₂ is connected to the solenoid 12b of the electromagnetic directional control valve 11 via the contact 38c of the relay 38, and the solenoid 12b is connected to the power supply 40 via the contact 39b of the relay 39. . Further, the cathode of the thyristor SCR ₂ is connected to the power supply side 40 via a resistor R ₅ , is connected to one end of an a-contact 38 b of a relay 38, and is further connected to the power supply side Connected to 40. The other end of the a contact 38b of the relay 38 is connected to the solenoid 12a of the electromagnetic direction control valve 11. Thyristor S
The gate of CR ₁ is connected to one end of resistor R ₁ ,
₁ of the other end is connected to one end of the one end and the limit switch LS ₂ a b-contact 41a of the relay 41. The other end of the b contact 41a of the relay 41 is connected to the power supply side 37 via the b contact 42a of the relay 42. The gate of the thyristor SCR ₂ is connected to one end of the resistor R _2, the other end of the resistor R ₂ is connected to one end of the limit switch LS _1. Limit switch LS ₁
The other end and the other end of the limit switch LS ₂ a is connected to the power source side 37 through a contact 42b of the relay 42.

Further, between the cathode of one thyristor SCR ₁ of the resistor R _1, a resistor R ₃ and capacitor C ₁ is connected in parallel,
And between the cathode of the resistance R ₂ of the one end and the thyristor SCR _2, the resistor R ₄ and connects the capacitor C ₂ is in parallel, further, the capacitor between the cathode of the cathode and the thyristor SCR ₂ of thyristor SCR ₁ C ₃ and C ₄ are connected in series.

One end of an a contact 43a of a relay 43 is connected to the power supply side 37, and the other end of the a contact 43a is connected to the power supply side 40 via the solenoid 34a of the two-position electromagnetic directional control valve 34.

One end of a water pump power switch 44 (cleaning device power switch) is connected to the power supply side 37, and the other end of the water pump power switch 44 is connected to a water pump drive electric circuit (not shown). Power supply side 40 via relay 43
Connected to

Further, one end of the relay 39 and one end of the relay 41 are connected to the power supply side 37, and the other end is connected to the power supply side 40 via the concrete pump operation switch 54. a contact 43
b is connected in parallel.

An a-contact 42c of the relay 42 and a b-contact 41b of the relay 41 are connected in parallel between one end of the relay 42 and the power supply side 37, and the other end of the relay 42 is connected to the power supply side 40.

A contact 43c of the relay 43 and the relay 38 are connected in series between the power supply side 37 and the power supply side 40.

 Next, the operation of the present embodiment will be described.

First, a case where only a concrete pump is operated without using a water pump will be described.

FIG. 1 shows the initial state, in which the proximity switch LS ₁ is opened,
Proximity switch LS ₂ is closed, one of the pistons 2a of the concrete-conveying cylinder 2 is advanced, the other piston 3a concrete transport cylinder 3 is retracted.

In this state, when the concrete pump operation switch 45 is closed, the relays 39 and 41 are simultaneously excited. When the relay 41 is excited, the b contact 41b is opened, but when the relay 42 is excited, the a contacts 42c and 42b are closed. Therefore, the gate current is supplied from the power supply side 37 to the a contact 42b of the relay 42 and the proximity switch LS _2.
Through the gate of thyristor SCR ₁ through the thyristor SC
R ₁ becomes conductive. As a result, the exciting current is supplied from the thyristor SCR ₁ to the solenoid 12 a of the electromagnetic directional control valve 11 via the b contact 38 a of the relay 38 and to the solenoid 21 b of the electromagnetic directional control valve 20. Therefore, the pilot pressure from the solenoid valve 12 due to the excitation of the solenoid 12a,
The pilot operation valve 13 operates from the neutral position, and the electromagnetic direction control valve 11 operates. Further, the pilot operation valve 22 is operated from the neutral position by the pilot pressure from the electromagnetic valve 21 by the excitation of the solenoid 21b, and the electromagnetic direction control valve 20 is operated.

As a result, oil is supplied from the auxiliary hydraulic pump 23 to the working chamber 6a of the swing cylinder 6 via the seventh pipe 24, the electromagnetic directional control valve 20, and the fifth pipe 18, so that the swing pipe 4 As shown by the dashed line, the swing tube 4 and the concrete transfer cylinder 3 are in communication with each other. At the same time, oil is supplied from the main hydraulic pump 14 to the third conduit 15, the electromagnetic directional control valve 11, the second conduit 10
Through the rod 8a of the hydraulic cylinder 8, the piston 3a moves forward, and the ready-mixed concrete in the other concrete transfer cylinder 3 passes through the swing pipe 4. And is discharged into the transport pipe 5.

As the rod 8a of the hydraulic cylinder 8 advances, the rod 7a of the hydraulic cylinder 7 retreats, the piston 2a retreats, the ready-mixed concrete is sucked from the hopper 1 into one of the concrete transfer cylinders 2, and one end of the cylinder moves. The oil in the chamber 7b returns to the hydraulic oil tank 16 via the first pipe 9, the electromagnetic directional control valve 11, and the fourth pipe 17.

The two-position electromagnetic directional control valve in the pressure control circuit 33
Reference numeral 34 is in a demagnetized state, and the pressure in the one-end-side working chambers 7b, 8b of the hydraulic cylinders 7, 8 is adjusted to a predetermined pressure by the action of the relief valve 35 for the main circuit.

At the same time when the forward movement of the rod 8a of the hydraulic cylinder 8 is proximity switch LS ₁ is closed, the retraction of the rod 7a of the hydraulic cylinder 7 is the proximity switch LS ₂ opens. When the switch LS ₁ as described above is closed, gate current from the power source side 37 flows through the a-contact 42b, the gate of the proximity switch LS ₁ through the thyristor SCR ₂ of relay 42, the thyristor SCR ₂ is turned on. As a result, the exciting current is supplied from the thyristor SCR ₂ to the solenoid 12b of the electromagnetic directional control valve 11 via the b contact 38c of the relay 38, and also to the solenoid 21a of the electromagnetic directional control valve 20. Therefore, the pilot operation valve 13 is operated by the pilot pressure from the electromagnetic valve 12 by the excitation of the solenoid 12b, and the electromagnetic direction control valve 11 is operated. The pilot operation valve 22 is operated by the pilot pressure from the solenoid valve 21 by the excitation of the solenoid 21a, and the electromagnetic direction control valve 20 is operated.

As a result, oil is supplied from the auxiliary hydraulic pump 23 to the working chamber 6b of the swing cylinder 6 through the seventh pipe 24, the electromagnetic directional control valve 20, and the sixth pipe 19, so that the swing pipe 4 As shown by the solid line, the state is switched, and the rocking pipe 4 and one concrete transfer cylinder 2 are in communication. At the same time, oil is supplied from the main hydraulic pump 14 to the one end side working chamber 7b of the hydraulic cylinder 7 via the third conduit 15, the electromagnetic directional control valve 11, and the first conduit 9, and is supplied via the rod 7a of the hydraulic cylinder 7. Piston 2a
Moves forward, and the ready-mixed concrete in one of the concrete transfer cylinders 2 is discharged to the transport pipe 5 through the swing pipe 4.

At the same time the proximity switch LS ₂ is closed by forward movement of the rod 7a of the hydraulic cylinder 7, the retraction of the rod 8a of the hydraulic cylinder 8 is opened proximity switch LS _1, the hydraulic cylinders 7 and 8, the state shown by the solid line, the state Are the same as those in FIG.

Thereafter, this operation is repeated, and the ready-mixed concrete in the hopper 1 is sent to the transport pipe 5 through the swing pipe 4 by the suction and discharge actions of the pair of concrete transfer cylinders 2 and 3.

In the case of the above operation, the manual switching valve 31 is at the neutral position, and the oil from the main hydraulic pump 14 is not sent to the water pump cylinder 27.

Next, a case where the water pump is used by operating the water pump cylinder 27 will be described. FIG. 1 shows one initial state, in which the proximity switch LS ₁ is opened, the proximity switch LS ₂ is closed, and the piston of one concrete transfer cylinder 2 is moved.
2a moves forward, and the piston 3a of the other concrete transfer cylinder 3 moves backward. In this state, the water pump power switch 44 is closed.

In FIG. 2, when the water pump power switch 44 is closed, current flows to the water pump driving electric circuit, and at the same time, the relay 43 is excited. When the relay 43 is excited, its a contact 43
a, 43b, 43c are closed.

When the a contact 43c of the relay 43 is closed, the relay 38 is excited, the a contacts 38b and 38d of the relay 38 are closed, and the b contact 3 is closed.
8a and 38c open.

When the a contact 43b of the relay 43 is closed, it becomes the same as the state where the concrete pump operation switch 45 is closed, and therefore,
The a-contact 42b of the relay 42 closes, and the b-contact 42a
Opens.

When the a contact 43a of the relay 43 is closed as described above, current is supplied from the power supply side 37 to the solenoid 34a of the two-position electromagnetic directional control valve 34 via the a contact 43a of the relay 43, and the solenoid 34a is excited. . As a result, the two-position electromagnetic directional control valve 34 is switched, and the hydraulic pressure in the branch circuit 26 is maintained at a higher pressure than that of the main circuit relief valve 35 by the action of the relief valve 36 for the water pump circuit. become.

Then, in the state as described above, flows into the gate of the thyristor SCR ₁ gate current from the power source side 37 through a contact 42b of the relay 42, the proximity switch LS _2, thyristor SCR ₁ is turned on. Thus, the exciting current is supplied to the solenoid 21b of the electromagnetic directional control valve 20 is supplied to the solenoid 12b of the electromagnetic directional control valve 11 via a contact point 38d of the relay 38 from the thyristor SCR _1. As a result, oil is supplied from the auxiliary hydraulic pump 23 to the seventh line 24, the electromagnetic directional control valve 20, the fifth line 18
Is supplied to the working chamber 6a of the swing cylinder 6 through the swing pipe 6, and the swing tube 4 is switched. At the same time, the oil is supplied from the main hydraulic pump 14 to the one end side working chamber 7b of the hydraulic cylinder 7 via the third pipe 15, the electromagnetic direction control valve 11, and the first pipe 9, so that the piston 2a moves forward, The piston 3a is in a state of being retracted, and the pistons 2a and 3a are stopped.

The initial state is different from the state shown by the solid line in FIG. 1, and as shown by the chain line in FIG. 1, in the initial state in which the piston 3a moves forward and the piston 2a moves backward, the proximity switch LS ₁
Is closed, the proximity switch LS ₂ is open.

In this case, as shown in FIG. 2, when the water pump power switch 44 is closed, a current flows to the water pump drive circuit, and at the same time, the relay 43 is excited. As described above, the relay 42
b of a contact 42b is closed, gate current from the power source side 37 is a contact 42b of the relay 42, the thyristor via a proximity switch LS ₁ S
It flows to the gate of the CR _2, thyristor SCR ₂ is turned on. As a result, the exciting current is transferred from the thyristor SCR ₂ to the relay.
The solenoid 1 of the electromagnetic directional control valve 11 through the a contact 38b of 38
2a and the solenoid of the electromagnetic directional control valve 20
Supplied to 21a.

Accordingly, oil is supplied from the main hydraulic pump 14 to the one-end working chamber 8b of the hydraulic cylinder 8 through the third pipe 15, the electromagnetic directional control valve 11, and the second pipe 10, so that the piston 3a moves forward, The piston 2a is in a state of being retracted, and the piston 2a
2a and 3a are stopped. As a result, the hydraulic cylinders 7, 8
A predetermined high pressure is generated in the first pipe 9, the second pipe 10, and the third pipe 15, and the inside of the branch pipe 26 is also maintained at the predetermined high pressure.

As described above, when the power switch for water pump 44 is closed, the hydraulic cylinders 7, 8 are stopped in a state of moving forward or backward.

When the manual switching valve 31 is switched under such conditions, the water pump cylinder is switched via the switching valve 28 in a state where the inside of the branch line 26 is maintained at a high pressure by the above-described water pump circuit relief valve 36. The oil is supplied to the working chambers 27a and 27b of the 27, and the water pump cylinder 27 reciprocates. Since the water pump is driven by the reciprocating operation of the water pump cylinder 27, the water is discharged into the transport pipe 5 to discharge the residual ready-mixed concrete and to clean the hopper 1 by the well-known method. Water is sprayed on to wash it.

When the water pump cylinder 27 is operated, the engine speed for rotating the main hydraulic pump 14 is linked with the switching operation of the water pump power switch 44, and the engine speed control lever (not shown) is electrically operated. The flow rate of the main hydraulic pump 14 is reduced by means of automatic lowering by operating with a servomotor or the like, and an appropriate flow rate of oil is supplied to the water pump cylinder 27.

 The operation of the switching valve 28 will be described in detail.

Although not shown, the electric circuit for reciprocating operation of the concrete transfer cylinders 2 and 3 is configured in the same manner as the electric circuit for reciprocating operation, and operates from a water pump drive electric circuit that operates in response to the operation of a switch that detects the stroke end of the piston of the water pump cylinder 27. When the command excites the solenoid 29a and demagnetizes the solenoid 29b, the solenoid valve 29 operates from the neutral position in the switching valve 28, and oil flows in the order of the pilot line 29c → the solenoid valve 29 → the pilot line 29d, The pilot operation valve 30 operates from the neutral position. At this time, the oil in the branch line 26 is released from the P port 28C of the switching valve 28 → the manual switching valve 31 → the oil passage 32A → the P port 30C of the pilot operated valve 30 → the pilot operated valve 30
The water is supplied into the working chamber 27a of the water pump cylinder 27 in the order of the A port 28A of the switching valve 28 and the cylinder side portion 26A of the branch pipe 26.

Along with this, the oil in the working chamber 27b of the water pump cylinder 27 is discharged from the cylinder side portion 26B of the branch line 26 → the B port 28B of the switching valve 28 → the pilot operation valve 30 → the pilot operation valve 3
Return to the hydraulic oil tank 16 in the order of 0 T port 30D → oil passage 32B.

In addition, when the solenoid 29a is demagnetized and the solenoid 29b is excited by a command from the water pump driving electric circuit, the pilot line 29c → the solenoid valve 29 → the pilot line 2
Oil flows in the order of 9f, pilot pressure is pilot operated valve
The oil in the branch line 26 acts on the P of the switching valve 28.
Port 28C → Manual switching valve 31 → Oil passage 32A → Pilot operated valve
30 P port 30C → pilot operated valve 30 → switching valve 2
8 are supplied into the working chamber 27b of the water pump cylinder 27 in the order of the B port 28B → the cylinder side portion 26B of the branch pipe 26.

Accordingly, the oil in the working chamber 27a of the water pump cylinder 27 is discharged from the cylinder side portion 26A of the branch pipe line 26 to the switching valve 2.
8. Return to the hydraulic oil tank 16 in the order of A port 28A, pilot operation valve 30, T port 30D of pilot operation valve 30, and oil passage 32B. As described above, the solenoids 29a and 29b are excited alternately by a command from the electric circuit for driving the water pump, whereby the water pump cylinder 27 reciprocates.

When the manual switching valve 31 is switched, the supply of oil from the branch pipe line 26 to the water pump cylinder 27 is stopped.

According to the configuration as described above, the water pump cylinder 27 can be driven by the oil taken out of the main circuit that operates the pair of hydraulic cylinders 7, 8 with the main hydraulic pump 14.
Unlike the conventional example, a new hydraulic pump for driving the water pump cylinder 27 is not required, and the apparatus can be simplified and inexpensive.

Further, since the switching valve 28 for shutting off the supply of oil to the water pump cylinder 27 is provided in the middle of the branch line 26 which branches off from the third line 15 and has a small flow rate, the third line has a large flow amount. The switching valve 28 can be made smaller as compared with the case where the switching valve 28 is provided halfway. Of course, in this case, the branch line 26
The flow rate in the inside is controlled to an appropriate value by reducing the rotation of the engine to reduce the supply amount from the main hydraulic pump 14.

In the present embodiment, the water pump cylinder 27 that reciprocates is used as the cleaning device actuator. However, the present invention is not limited to this, and the water pump rotation that rotates by the oil from the main hydraulic pump 14 is used. A rotary water pump such as an axial flow type can be operated using the device,
The inside of the hopper 1 and the inside of the transport pipe 5 can also be washed with air using a compressor that uses oil from the main hydraulic pump 14 as rotational force.

In this embodiment, when the water pump cylinder 27 is operated, the swing cylinder 6 does not reciprocate.
As shown in FIG. 3, the circuit of the solenoid valve directional control valve 20 includes a swing cylinder automatic reciprocating switch SW, a timer T, and a relay R.
And a potential circuit composed of these a-contacts R _a and b-contacts _Rb is provided. The electric circuit alternately supplies current to the solenoids 21 a and 21 b of the electromagnetic directional control valve 20 to reciprocate the swing cylinder 6. be able to.

Therefore, when water is injected from the water pump by the reciprocating operation of the water pump cylinder 27, the transport pipe 5 and the hopper 1 can be simultaneously washed while the swing cylinder 6 is reciprocated to drive the swing pipe 4. . Further, only the inside of the hopper 1 can be cleaned.

[Effect of the invention]

As described above, according to the present invention, firstly, the cleaning device actuator can be driven by the oil taken out from the main circuit that operates the pair of hydraulic cylinders by the main hydraulic pump. In addition, a new hydraulic pump for driving the actuator for the cleaning device is not required, and the device can be simplified and inexpensive.

Secondly, when operating a cleaning device such as a water pump, by switching the power switch for the cleaning device, the number of revolutions of the engine that rotates the main hydraulic pump is reduced, and in conjunction with this, the cleaning device switching valve is opened. State
The small flow pressure oil flows in the order of the main hydraulic pump → branch line → cleaning device switching valve → cleaning device actuator → tank to drive the cleaning device actuator.

Therefore, it is possible to simultaneously perform the cleaning of the transport pipe and the cleaning of the inside of the hopper by spraying the cleaning water from a water pump or the like operated by the cleaning device actuator.

Third, when the actuator for the cleaning device is operated, the flow rate of the main hydraulic pump is reduced by lowering the rotation speed of the engine that rotates the main hydraulic pump in conjunction with the switching operation of the power switch for the cleaning device. The flow rate of the oil supplied to the actuator can be reduced. Since the cleaning device switching valve for shutting off the supply of oil to the cleaning device actuator is provided in the middle of the branch flow line which branches off from the hydraulic pipeline for driving the concrete transfer cylinder and has a small flow rate, As compared with the case where the valve is directly provided in the middle of a hydraulic pipe for driving a concrete transfer cylinder, the cleaning device switching valve can be configured to be small in size, which is a practical effect.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of a concrete pump according to an embodiment of the present invention. FIG. 2 is an electric circuit diagram of the concrete pump. FIG. 3 is an electric circuit diagram according to another embodiment of the present invention. FIG. 4 is a hydraulic circuit diagram of a conventional concrete pump. FIG. 5 is another hydraulic circuit diagram of a conventional concrete pump. [Description of Signs of Main Parts] 1 ... Hopper 2, 3 ... Cylinder for concrete transfer 2a, 3a ... Piston 4 ... Swinging tube 5 ... Transport tube 6 ... Hydraulic cylinder for valve actuation (swing cylinder) 7,8 ... Hydraulic cylinder 7b, 8b ... One end side working chamber 9 ... First pipe 10 ... Second pipe 11 ... Electromagnetic directional control valve 14 ... Main hydraulic pump 15 ... Third pipe Channel 26 Branch pipe 27 Water pump cylinder 28 Switching valve.

Claims (1)

(57) [Scope of request for utility model registration] 1. A hopper for charging ready-mixed concrete, a pair of concrete transfer cylinders for sucking and discharging the ready-mixed concrete in the hopper by a piston, and a pair of concrete transfer cylinders driven by a valve operating cylinder. A flow path switching valve that alternately communicates a transport pipe with one of the cylinders and alternately communicates the other with the hopper, and vice versa, and moves a piston in a pair of concrete transfer cylinders forward and backward. A pair of hydraulic cylinders to be retracted, a directional control valve connected to one end side working chamber of each of the pair of hydraulic cylinders via a pipeline, and a main hydraulic pump respectively connected to the directional control valve via a pipeline. Switching is performed in conjunction with the switching operation of the direction control valves for the pair of hydraulic cylinders, and the communication operation and the reverse communication operation are performed in reverse. An electromagnetic direction control valve for switching the flow path of the pressure oil to a valve operating cylinder for operating the flow path switching valve, and a cleaning device actuator for operating a cleaning device such as a water pump. A concrete pump comprising: a branch pipe connected in the middle of a pipe connecting the main hydraulic pump and the directional control valve; and a cleaning device actuator and a cleaning device actuator provided in the branch pipe. A cleaning device switching valve including a switching valve for supplying and shutting off the pressure oil and a solenoid valve for repeatedly operating the cleaning device actuator; and a cleaning device power switch for opening and closing an electric circuit for driving the cleaning device switching valve. And when the actuator for the cleaning device is operated, the main hydraulic pump is operated in conjunction with a switching operation of a power switch for the cleaning device. Means for lowering the number of revolutions of the engine that rotates the hydraulic pump.