JPH0432396Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is a cylinder sequential operation device that sequentially expands and contracts two cylinders in a predetermined order, such as a cylinder device used to extend and retract the boom of a hydraulic truck crane. It is related to.

[Conventional technology]

For example, when extending and retracting the boom of a hydraulic truck crane, from the viewpoint of boom strength, when extending the boom, the thick second boom of the first boom at the base is first extended completely by the first cylinder, and then the second cylinder When extending and conversely retracting the third boom, it is preferable to first retract the second cylinder to fully retract the third boom, and then retract the first cylinder to retract the second boom.

Many techniques have been proposed in the past for sequentially operating the cylinders in this manner. For example, the effective diameters of the hydraulic cylinders in each stage are made different, or solenoid valves are used to sequentially operate the cylinders.

[The problem that the idea aims to solve]

However, with such conventional systems, changes in cylinder sliding resistance result in unstable operation, and those that use solenoid valves require complicated wiring and expensive solenoid valves. There was a problem.

The present invention solves the above-mentioned problems of the conventional ones, has an extremely simple structure for switching the circuits of the first and second cylinders, has stable operation, does not require expensive parts, and has high reliability. The object is to provide a high cylinder sequential actuation device.

[Means to solve the problem]

The present invention includes a hydraulic pump, a directional valve, and a first
A cylinder sequential actuation device comprising a cylinder, a second cylinder, and a hydraulic circuit connecting these devices, and configured to sequentially extend or contract the first and second cylinders by switching the directional control valve. The discharge pressure circuit at the time of extension and the piston head side chamber of the first cylinder are connected via a check valve that opens toward the first cylinder piston head side chamber, and the discharge pressure circuit at the time of extension and the piston head side chamber of the second cylinder are connected. The head side chamber is connected to the head side chamber through a single spool directional switching valve, and the second cylinder is provided with a forcing member for forcibly opening the check valve when the second cylinder is at its minimum contraction, and the hydraulic pump is connected to the head side chamber through a single spool directional switching valve. a shuttle valve that guides pressure and operates the single spool directional control valve by outlet pressure; and a shuttle valve that is interposed between one inlet of the shuttle valve and the discharge pressure circuit during extension, and is oriented to transmit the operating pressure during extension. and an operating check valve that opens in the opposite direction, the other inlet of the shuttle valve communicating with the piston rod side chamber of the first cylinder, and the operating check valve opening in the first cylinder when the first cylinder is fully extended. This cylinder sequential operating device is characterized by being equipped with an operating force member for forcibly opening a valve.

[Effect]

In the present invention, when the cylinder is extended, the discharge pressure of the hydraulic pump is extended by the check valve that opens toward the side chamber of the piston head of the first cylinder, but during this time the operating pressure is transferred through the shuttle valve. The single spool directional control valve, which sends pressure oil to the piston head side chamber of the second cylinder, remains closed due to the operation of the check valve, which opens in the opposite direction to the direction that the signal is transmitted to the single spool directional control valve, so the second cylinder is not operated. It does not expand.

When the first cylinder is fully extended, the operating check valve is forcibly opened by the action of the operating forcing member, operating pressure is transmitted through one inlet of the shuttle valve, the single spool directional control valve is opened, and the second
The cylinders are actuated and extended, and in this way the extensions can be carried out sequentially.

During contraction, the discharge oil of the hydraulic pump is switched by a directional control valve and flows into the cylinder device in the opposite direction.

Pressure oil enters the piston rod side chambers of the first and second cylinders, but the return circuit in the piston head side chamber of the first cylinder is closed by the action of the check valve, so oil cannot be drained, and the first cylinder does not operate. Does not shrink. On the other hand, the operating pressure is transmitted to the second cylinder piston head side chamber via the other inlet of the shuttle valve by the pilot circuit from the first cylinder piston head side chamber, and the single spool directional control valve is opened, allowing oil to be drained. This allows the second cylinder to operate and contract.

When the second cylinder is completely retracted, the check valve is forcibly opened by the force member, so that the piston head side chamber of the first cylinder can drain oil, and the first cylinder is activated and retracted, and in this way, A reduction is performed.

As described above, the hydraulic circuit is controlled by a check valve, a single spool directional control valve, a shuttle valve, an operation check valve, a force member that forcibly opens the check valve, and an operation force member that forcibly opens the operation check valve. is automatically switched, and when extending, the first cylinder and the second cylinder are extended in that order, and when contracting, the second cylinder and the first cylinder are contracted in that order, and the structure is extremely simple to perform these operations. Therefore, there are fewer parts that fail, and high reliability can be achieved.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings.

1 is a hydraulic pump, 2 is a directional control valve, 3 is a counterbalance valve, 4 is a first cylinder, 5 is a second cylinder, and 6 is a valve device provided in the first cylinder 4.

In the first cylinder 4, a piston 9 having a hollow piston rod 8 is reciprocatably housed in a cylinder tube 7. A hollow portion 10 of the piston rod 8 is provided with a hollow rod 12 (acting as a forceful member for operation as described later) that has a guide 11 and is slidably supported both with respect to the piston 9 and with respect to the cylinder tube 7. It is being The hollow portion 13 of the hollow rod 12 communicates with the hollow portion 10 at one end, has a port 14 near the other end, and has a valve body 1 of an operation check valve 15 to be described later.
A holder 17 is provided to hold 6 and forcibly move it.

The hollow portion 10 of the piston rod 8 communicates with the outside through a port 18. The piston rod 8 is provided with a communication passage 22 that communicates ports 20 and 21 that open to the outside and the piston rod side chamber 19 of the cylinder tube 7. The ports 18 and 20 are connected to the directional valve 2 via the counterbalance valve 3.

The cylinder tube 7 has a port 23 in the piston rod side chamber 19 for taking out high-rod pressure.
and a port 24 for connecting with the second cylinder 5.
The piston head side chamber 25 is provided with a port 26 for supplying and draining oil.

In the case of a hydraulic telescopic boom, the base of the piston rod 8 of the first cylinder 4 is pivotally connected to the first boom at the base by a pin 27, and the base of the piston rod 29 of the cylinder tube 7 and the second cylinder 5 is connected to the base of the first boom by a pin 27.
7' is pivotally connected to the second boom, and the cylinder tube 28 of the second cylinder 5 is also pivotally connected to the third boom.

In the second cylinder 5, a piston 30 having a hollow piston rod 29 is reciprocatably accommodated in the cylinder tube 28. The hollow portion 31 has a port 32 communicating with the outside and a port 34 communicating with a piston head side chamber 33. 35 is a communication passage, and a port 36 communicates with the port 24 of the cylinder tube 7 of the first cylinder 4.
and a port 38 communicating with the piston rod side chamber 37.
have.

In the valve device 6, a spring-offset, pilot-operated, two-port, two-position, single-spool directional valve 39 is operated by operating pressure from the outlet of a shuttle valve 42, which has check valves 40, 41 at its two inlets, respectively. It's becoming like that. The operating pressure from the port 14 is transmitted to one inlet of the check valve 40 during expansion, and an operating check valve 15 that opens in the opposite direction to the direction in which the operating pressure is transmitted is provided in the middle. The valve body 16 of the operation check valve 15 has a hollow rod 12 as an operation force member that is connected to the first cylinder 4.
When the piston 9 is fully extended, the back surface of the piston 9 is the guide 1
1 and is pulled slightly to the left, the holder 17 is forcibly released independently of the operating pressure, and at this time the operating pressure is transferred to the single spool direction via the shuttle valve 42. The signal is transmitted to the switching valve 39 to open it.
The other inlet with the check valve 41 is communicated with the piston rod side chamber 19 of the first cylinder 4, and the operating pressure from the port 23 is transmitted during contraction to open the single spool directional control valve 39.

Operation 4 Check valve 15, a circuit connecting this to the discharge pressure circuit during extension, and a shuttle valve 42
and a circuit connecting the other inlet to the piston rod side chamber 19 of the first cylinder 4 form a pilot circuit for operating the single spool direction switching valve 39.

Port 43 of single spool directional valve 39
is connected to port 14, and port 44 is connected to port 32 of second cylinder 5.

Port 14 and port 26, that is, the discharge pressure circuit during expansion and the piston head side chamber 25 of the first cylinder 4
is connected via a check valve 45, which opens toward the port 26 of the piston head side chamber 25 of the first cylinder 4, and is connected to an arm 46 attached to the cylinder tube 28. Due to the provided striker 47 as a forcing member, when the second cylinder 5 is most contracted, it is forcibly opened regardless of the back pressure.

48 is an oil tank, 49 is a strainer, and 50 is a relief valve.

The operation will be explained.

When the hydraulic pump 1 is operated and the directional control valve 2 is switched to the left position with both the first cylinder 4 and the second cylinder 5 in the most contracted state, the pressure oil flows from the port 18 to the hollow part 10 and to the hollow rod 1.
2, port 14, check valve 45 and the first
The oil in the piston head side chamber 25 of the cylinder 4 enters, while the oil in the piston rod side chamber 19 of the first cylinder 4 is discharged from the port 20 through the communication passage 22 and returns to the oil tank 48, and the first cylinder 4 is extended. At this time, the operation check valve 15 is closed, and therefore the single spool directional control valve 39 is closed, so the second cylinder 5 is not operated and remains contracted. Note that the striker 47 forcibly opens the check valve 45.

When the first cylinder 4 is fully extended, the hollow rod 1
The second guide 11 hits the back side of the piston 9 and stops, but the cylinder tube 7 further extends slightly. At this time, the valve body 16 is pulled and remains through the holder 17, and the operation check valve 15 is forcibly opened. Then, the operating pressure from the port 14 passes through the operating check valve 15 and check valve 40 to operate the single spool directional control valve 39 to open it.

There, pressure oil flows from port 32 to second cylinder 5.
The oil in the piston head side chamber 37 enters the piston head side chamber 33 through the hollow part 31, while the oil in the piston rod side chamber 37 flows through the port 38, the communication passage 35, the port 36, and the first cylinder 4.
Returns to the oil tank 48 from the port 20 via the piston rod side chamber 19, port 21, and communication path 22,
The second cylinder 5 is extended.

When contracting the cylinder, the flow path is reversed by switching the directional control valve 2 to the right position, and pressure oil is guided from the port 20 to the piston rod side chamber 19 via the communication path 22 and port 21. but,
The oil in the piston head side chamber 25 is checked by the check valve 4.
Due to the action of 5, oil cannot be drained, and the first cylinder 4 does not contract and remains as it is.

On the other hand, pressure oil is connected to ports 24, 36 and communication path 3.
5. The oil in the piston rod side chamber 37 of the second cylinder 5 is supplied through the port 38, and the oil in the piston head side chamber 33 passes through the port 34 and the hollow part 31, and reaches the port 44 of the single spool directional control valve 39 from the port 32. Check valve 4 from
through the single spool directional valve 39 which is opened by the operating pressure transmitted via the port 14, the hollow part 13 of the hollow rod 12, the hollow part 1
0, port 18, and is discharged to the oil tank 48 through the counterbalance valve 3, and first the second cylinder 5 contracts.

When the second cylinder 5 is fully compressed, the striker 4
7 forcibly opens the check valve 45. Then, the piston head side chamber 25 of the first cylinder 4
The oil in the port 26, the check valve 45, the port 14, the hollow part 13 of the hollow rod 12, the hollow part 1
0, the oil will be drained into the oil tank 48 via the counterbalance valve 3, and the first cylinder 4 will operate and contract, reaching the maximum contraction.

When the directional control valve 2 is returned to neutral, the single spool directional control valve 39 loses operating pressure and returns to its closed position due to the spring, and the valve body 16 of the operation check valve 15
The spring also returns the hollow rod 12 to its original position.

As described above, the first and second cylinders are contracted in this order during extension, and the second and first cylinders are contracted in that order during contraction, so that the telescopic boom can always be maintained at its maximum strength.

(Effect of the invention) With this invention, the single spool directional control valve,
By combining the shuttle valve, operation check valve, and check valve, one of the two cylinders is securely closed and stopped by closing the single spool directional control valve, and the other is expanded and contracted preferentially, while the preceding cylinder reaches the end of its stroke. When this occurs, the check valve or operating check valve is forcibly opened by a force-acting member, thereby opening the shut-off of the single spool directional control valve and allowing the other cylinder to operate next. Therefore, we can provide a cylinder sequential actuation device that has extremely simple components, does not require expensive parts, operates reliably and stably, is easy to maintain, and is highly reliable. be effective.

[Brief explanation of the drawing]

The drawing is a flow diagram of an embodiment of the present invention. 1... Hydraulic pump, 2... Directional switching valve, 3...
Counter balance valve, 4...1st cylinder, 5...
... Second cylinder, 6 ... Valve device, 7 ... Cylinder tube, 8 ... Piston rod, 9 ... Piston, 10 ... Hollow part, 11 ... Guide, 12
... Hollow rod, 13 ... Hollow part, 14 ... Port, 15 ... Operation check valve, 16 ... Valve body, 17 ... Holder, 18 ... Port, 19 ...
Piston rod side chamber, 20... port, 21...
Port, 22...Communication path, 23...Port, 24
... Port, 25 ... Piston head side chamber, 26
... Port, 27, 27' ... Pin, 28 ... Cylinder tube, 29 ... Piston rod, 30
... Piston, 31 ... Hollow part, 32 ... Port, 33 ... Piston head side chamber, 34 ... Port, 35 ... Communication passage, 36 ... Port, 37 ...
Piston rod side chamber, 38... port, 39...
Single spool directional control valve, 40...Check valve, 41...Check valve, 42...Shuttle valve, 43...Port, 44...Port, 45
...Check valve, 46...Arm, 47...
Striker, 48...Oil tank, 49...Strainer, 50...Relief valve.

Claims (1)

[Scope of utility model registration request] A hydraulic pump, a directional control valve, a first cylinder, a second cylinder, and a hydraulic circuit connecting these devices are provided, and the first and second cylinders are sequentially expanded or contracted by switching the directional control valve. In a cylinder sequential actuation device configured to
The discharge pressure circuit during extension and the piston head side chamber of the first cylinder are connected via a check valve that opens toward the first cylinder piston head side chamber. The piston head side chamber is connected via a single spool directional control valve, and the second cylinder has a
a shuttle valve comprising a force member for forcibly opening the check valve when the second cylinder is at its maximum contraction, guiding the pressure of the hydraulic pump and operating the single spool directional control valve by outlet pressure; An operation check valve is interposed between one inlet of the shuttle valve and the discharge pressure circuit during expansion, and opens in a direction opposite to the direction in which the operation pressure is transmitted during expansion, and the other inlet of the shuttle valve is connected to the first discharge pressure circuit. Cylinder sequential actuation device, characterized in that the first cylinder is provided with an operation forcing member that is communicated with a piston rod side chamber of the cylinder and forcibly opens the operation check valve when the first cylinder is fully extended. .