JPS58130887A - Expansion device for cylinder - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylinder device suitable for the boom of a hydraulic crane, etc. For safety reasons, when the boom of a crane is extended, it extends sequentially from the base end to the distal end, and then contracts. When it is small, it is desirable to reduce it sequentially from the distal side to the proximal side.

The applicant had previously filed a patent application filed in 1983 regarding the technical concept of two cylinder devices in which each cylinder device expands and contracts sequentially.
No. 7980 (Unexamined Japanese Patent Publication No. 54-55951) and Patent Application No. 1973
The application was filed as No. 5-31461. These applications attempted to achieve sequential expansion and contraction using a pilot operation method, resulting in complicated structures. In the present application, the structure is simplified by sequentially expanding and contracting using a linear motion system.

The invention will be explained below with reference to the drawings.

The figure shows an example embodiment of the present invention, and A is a cylinder portion a.
1. a first cylinder device consisting of a piston rod portion a2;
B is a second cylinder device consisting of a cylinder part b1 and a piston rod part b2, and the base end boom,
3 which is slidably inserted into the intermediate boom and the tip boom in sequence.
Attach to the stage boom.

That is, the piston rod portion a2 of the first cylinder device A is used as the proximal boom, the cylinder portion a1 and the cylinder portion bl of the second cylinder device B are used as the intermediate boom, and the piston rod portion b!
are attached to the tip of the boom to form a three-stage telescopic boom.

1 is an oil tank, 2 is an oil pump, and 3 is a control valve, which constitute an oil supply and discharge device.

4 is a pipe that connects the control pulp 3 to the extension side oil chamber 16 of the first cylinder device A, 5 is a pipe that connects to the contraction side oil chamber 10, and 6 is a piston rod that connects to the contraction side oil chamber 10 of the first cylinder device. A port provided at the end of a-, 8 is a port communicating with the same extension side oil chamber 16, and 7 is a contraction side oil chamber 10.14 of the first cylinder device A and second cylinder device B.
9 is a passage in the piston rod a2 that connects the reduction side oil chamber 10 of the first cylinder device A and the aforementioned port 6, and communicates with the reduction side oil chamber 10 via an oil passage 56. ing. 10 is a contraction side oil chamber of the first cylinder device A, 11 is a port of the contraction side oil chamber 14 of the second cylinder device B, 12 is provided in the piston rod a2 of the first cylinder device A,
It is an intermediate pipe that passes through the piston 15 and reaches a cylinder end portion 52, and a valve 24 is provided in the cylinder end portion 52.

In addition, the middle pipe 12 is normally pushed to the left by a spring 21 and a valve 24 blocks off the oil chamber 22 and the oil chamber 34, but the first
At the end of the extension of the cylinder A, the end 54 of the middle pipe 12 comes into contact with the piston 15 and is moved to the right, so that the valve 24 is operated and the oil chamber 22 and the oil chamber 34 are communicated with each other. Reference numeral 13 denotes a passage within the middle pipe 12, with one side communicating with the aforementioned port 8, and the other side communicating with an oil chamber 57 within the valve 24. 25
is a passage connecting this oil chamber 57 and the aforementioned oil chamber 22;
is a check valve installed in the oil chamber 57 that keeps the spring 48
, allowing oil to flow from the oil chamber 54 to the oil chamber 57 side and preventing the reverse flow.

The oil chamber 54 includes a passage 58, a port 53, a pipe 32, and a port 55 provided in the cylinder end portion 19 of the second cylinder device B.
It communicates with the extension side oil chamber 20 of the second cylinder device B via. 18 is a piston of the second cylinder device B. Next, 38 is a valve provided in the cylinder end portion 19 of the second cylinder device B, which is always urged by a spring 35 to close the oil chamber 59 and the oil chamber 60, but when pressure oil acts on the oil chamber 59. In some cases, it has a checking function that allows oil to flow from oil chamber 59 to oil chamber 60, but prevents the reverse flow. In addition, the valve 38 is in an unrestricted state, and one end 38a thereof penetrates the end surface of the cylinder end portion 19 of the second cylinder device B and protrudes into the extension side oil chamber 20. The piston 18 of the second cylinder device B engages with the valve 38a and pushes the valve 38 against the spring 35, so that the oil chamber 59 and the oil chamber 60 communicate with each other.

The reason why the valve 38 is provided with a hole 39 and an oil chamber 49 on the other end side is to balance the pressure so that the valve 38 is not affected by the pressure oil in the extension side oil chamber 20 of the second cylinder device B when contracting. Don't take it. 61 is a pipe connecting the oil chamber 59 and the aforementioned oil chamber 22 via a port 70.71, and 62 is a pipe connecting the oil chamber 60 and the extension side oil chamber 16 of the first cylinder device A via a port 72.73. It's plumbing. Note that 51 is the ground part of the first cylinder device A, and 64 is the first part to which the pipe 7 is connected.
The port 65 of the contraction side oil chamber 10 of the cylinder device A is a counterbalance valve installed near the inlet of the supply/discharge port 6.8 of the first cylinder device A. It is configured to allow the flow of pressure oil and block the flow in the opposite direction, but is operated by pilot pressure from the oil supply side piping 5 side at the time of contraction to allow the flow in the opposite direction. .

Next, the operation of the cylinder expansion and contraction device provided with the sequential operation mechanism configured as described above will be explained.

In the figure, both the first and second cylinder devices A%B are in the most contracted state. In this state, when the control valve 3 is switched to the right chamber position shown in the figure, the pressure oil of the pump 2 is transferred to the pipe 4, the counterbalance valve 63, the port 8, the passage 13 in the middle pipe 12, the oil chamber 57 in the valve 24, It further enters the oil chamber 22 via the passage 25. Since the valve 24 is pushed to the left by the spring 21, the oil chamber 22 and the oil chamber 54 are not in communication with each other, and therefore the pressure oil is transferred to the extension side oil chamber 20 of the second cylinder device B.
, and the second cylinder device B does not extend. The pressure oil in the oil chamber 22 reaches the oil chamber 59 provided in the cylinder end portion 19 of the second cylinder device B via the port 70, the piping 61, and the port 71, and then flows through the oil chamber 60, the port 72, the piping 62, and the port 75. The extension side oil chamber 1 of the first cylinder device A
6 and the first cylinder device A expands. In this case, if the second cylinder device B is slightly extended, and therefore the end 38a of the valve body is not pushed by the piston 18, and the oil chamber 59 and the oil chamber 60 are closed by the spring 55. Even if the valve 38 is opened by the pressure oil acting on the oil chamber 59, the extension side oil chamber 1 of the first cylinder device A is opened.
Pressure oil flows into 6, and the first syringing device extends. When the first cylinder device 8 expands in this way, the oil in the contraction side oil chamber 10 of the first cylinder device A returns to the tank 1 via the passage 56, passage 9, port 6, and piping 5. As this state progresses and the first cylinder device A reaches its maximum extension, the end 54 of the middle pipe 12 and the piston 15 of the first cylinder A come into contact.

At this point, the valve 24 is still pushed to the left by the spring 21, but the extension side oil chamber 16 of the first cylinder device A
When pressure oil enters, the force of the spring 21 is overcome by the thrust generated on the piston 15 by the pressure oil in the oil chamber 16, and the valve 24 is moved to the right, and the oil chamber 22 and the oil chamber 34 communicate with each other. It enters the extension side oil chamber 20 of the second cylinder device B via the passage 58, port 53, piping 32, and port 55. This causes the second cylinder B to begin to expand. On the other hand, the first
The pressure oil that communicated with the extension side oil chamber 16 of the cylinder device A is
When the piston 15 comes into contact with the gland 51 of the first cylinder A and the first cylinder device stops expanding, no further flow occurs.

When the second cylinder device B extends, the end 58a of the valve 58 and the piston 18 are brought into a non-contact state, and the valve 38 is pushed to the left by the force of the spring 55, thereby blocking the oil chamber 59 and the oil chamber 60. Note that even if the oil chamber 59 and the oil chamber 60 are in the blocked state, if the first cylinder device A is in an extendable state (assuming that the first cylinder device A is contracted for some reason),
Pressure oil pushes open the valve 38 and flows into the extension-side oil chamber 16, causing the first cylinder device A to extend. This means that during extension, the first cylinder device A is always held in the most extended state. With the expansion of the second cylinder device B,
The oil in the reduction side oil chamber 14 passes through the port 11, the piping 7, the reduction side oil chamber 10 of the first cylinder device A, the passage 9, and the port 6 and returns to the tank.

Next, the reduction operation will be explained.

When the control valve 3 is switched to the left chamber in the figure when the first and second cylinder devices A and B are in the most extended state, pressure oil acts on the contraction side oil chamber 10 of the second cylinder device B.
The oil in the extension side oil chamber 16 of the first cylinder device A cannot escape because the oil chamber 59 and the oil chamber 60 are shut off by the valve 38, and therefore the first cylinder device A does not contract. The oil in the extension side oil chamber 20 of the second cylinder device B is connected to the port 55 and the piping 3.
2. The oil reaches the oil chamber 34 through the port 53 and the passage 58, and flows into the oil chamber 57 in the valve 24 through the oil chamber 22 or by directly pushing open the check valve 53.
Return to tank 1.

The second cylinder device B therefore contracts.

If the first cylinder device A does not contract and only the second cylinder device B begins to contract, the piston 18 of the second cylinder device B will open at the valve 5 just before the second cylinder device B reaches its minimum contraction state.
The valve 58 is brought into contact engagement with the end 38a of the valve 58 by the spring 35.
It will overcome the force pushing and communicate with the oil chamber 60.

Then, the pressure oil in the extension side oil chamber 16 of the first cylinder device A is transferred to the port 73, the piping 62, the port 72, the oil chamber 60%, the oil chamber 59, the port 71, the piping 61, the port 70, the oil chamber 22.
, across the oil chamber 57 in the valve 24, and further returns to the tank via the passage 13, port 8, etc. When the first cylinder device A starts to contract, the piston 15 moves to the left, and this piston 1
5 and the end 54 of the middle pipe 12 are in a non-contact state, so the valve 24 is returned to the left by the spring 21, and the oil chamber 3
4 and the oil chamber 22. At this time, even if pressure oil is trapped in the oil chamber 64 or the like, or even if the second cylinder device B is not completely contracted, the second
The oil in the extension side oil chamber 20 of the cylinder device B is checked by the check valve '5.
Press 6 and exit to the tank side. This means that during contraction, the second cylinder device B is always held in the minimum contraction state.

As the oil in the extension side oil chamber 16 of the first cylinder device A returns to the tank 1 in this manner, the oil in the first cylinder device A is brought into the minimum contracted state.

[Brief explanation of the drawing]

The figure is a sectional view of a cylinder expansion/contraction device according to the present invention. A...First cylinder device, B...Second cylinder device, 10.14...Reduction side oil chamber, 16.20...Extension side oil chamber, 24.38...Valve.

Claims (1)

[Claims] ■ The reduction side oil (10) and (14) of the first and second cylinder devices (A) and (B) are communicated, and the reduction side oil chamber (10) of the first cylinder device (A) is connected to the oil Connect to supply/discharge equipment,
From this oil supply/drainage device to the first and second cylinder devices (C, (B)
) The cylinder end portion (52) of the first cylinder device (4) in the middle of the supply/discharge circuit to the extension side oil chamber (16), (2o)
At the time of extension, the first cylinder 2 device (A) operates at the end of extension to supply the oil supply side to the extension side oil chamber (B) of the second cylinder device (B).
20) and a valve (24) leading to the second cylinder device (
When the cylinder end part (19) of B) is retracted, the second cylinder device (B) operates at the end of the contraction and the first cylinder device (B) is activated.
Valve (58) that connects the extension side oil chamber (16) of A) to the oil drain side
The valve (24) always communicates the extension side oil chamber (20) of the second cylinder device (B) to the oil drain side when contracted, and the valve (58) has one end (Saa) The piston (18) of the second cylinder device (B) and the valve (38) protrude into the extension side oil chamber (20) in the second cylinder device (B), and at the end of the contraction of the second cylinder device, the piston (18) of the second cylinder device (B) and the valve (38) one end (38a) is engaged with the oil passage to the oil drain side, and the oil supply side is always connected to the extension side oil chamber (16) of the first cylinder device (A) during extension; Further, from the front oil supply/discharge device to the first cylinder device (A) supply/discharge boat (6),
In the middle of the piping to (8), the flow of oil into the oil chamber on the extension side is allowed, but the flow in the opposite direction is blocked. A cylinder expansion/contraction device characterized by being provided with a counterbalance valve (63) that allows flow in this direction.