JPS636151Y2 - - Google Patents

Description

[Detailed description of the invention] This invention includes two hydraulic cylinders, an upper hydraulic oil pipe connected to the upper chamber of the hydraulic cylinder, and first and second lower hydraulic oil pipes connected to the lower chamber of the hydraulic cylinder. This invention relates to a protection device for a hydraulic lifting mechanism consisting of a main pipe and a lower hydraulic oil main pipe where both of the lower hydraulic oil branch pipes are combined, and in particular, the upper hydraulic oil pipe, the lower hydraulic oil main pipe, and the first and second operating oil main pipes. A check valve with a pilot opening/closing mechanism is provided in each oil branch pipe, and a check valve with a pilot opening/closing mechanism is provided between the four check valves and the lower hydraulic oil main pipe, upper hydraulic oil pipe, second lower hydraulic oil branch pipe, and first lower hydraulic oil branch pipe, respectively. This invention relates to a protection device in a hydraulic lifting mechanism formed by a pilot line.

In general, in a hydraulic lifting mechanism with a hydraulic cylinder, if the hydraulic oil pipe is damaged, the holding process, especially,
If it is held at the top, the elevating member, which is supposed to be stopped, will come down, which may cause injury to the worker, which is not desirable from a labor safety perspective. The problem was that the work was incomplete.

Therefore, in conventional hydraulic lifting mechanisms, such as boosters in vertical injection molding machines, a solenoid valve is provided near the hydraulic oil hole in the lower chamber of the hydraulic cylinder, and only during the lifting and lowering processes of the lifting member. The solenoid valve is opened to allow hydraulic oil to pass therethrough, and in the holding step, the solenoid valve is closed to prevent the lifting member from descending in the event that the hydraulic oil pipe is damaged.

However, although the above-mentioned conventional technology solves the problem in the holding process, if the hydraulic oil pipe is damaged in the lowering process, the lifting member cannot be stopped, and the lifting member rapidly lowers as the pressure drops. In addition to being extremely dangerous for the operator, the work member also has the drawback of being damaged by the collision.

For example, when used as a booster for an injection molding machine, the upper mold may drop suddenly during the lowering process and collide with the lower mold at high speed, potentially damaging the mold. Moreover, it was extremely dangerous for workers.

Furthermore, in a hydraulic lifting mechanism using two or more hydraulic cylinders, one of the solenoid valves installed near the hydraulic oil hole in the lower chamber of each hydraulic cylinder does not open during the lowering process and remains closed. If this happens, the problem is that only one side of the force acts on the hydraulic piston, which may cause damage to the mechanism.

In view of the problems such as rapid descent and damage of the lifting member due to the structural limitations of the hydraulic lifting mechanism based on the above-mentioned conventional technology, this invention provides a check valve with a pilot opening/closing mechanism in each hydraulic oil pipe, and a check valve with a pilot opening/closing mechanism is installed in each hydraulic oil pipe. By forming a pilot line between each of the hydraulic oil pipes, it is an object of the present invention to provide an excellent protection device for a hydraulic lifting mechanism that eliminates the above-mentioned drawbacks, solves the difficulties, and allows extremely safe work.

The structure of this invention in accordance with the above purpose is that during normal operation during the descending process, each check valve in the upper hydraulic oil pipe, lower hydraulic oil branch pipe, and lower hydraulic oil main pipe is opened by pressure from each hydraulic oil pipe through the pilot line. If the pressure drop occurs due to damage or other abnormality in either the lower hydraulic oil main or branch pipe, the pressure to the check valve through the pilot line will disappear, and the lower hydraulic oil will be lowered. The check valve in one of the oil branch pipes or the check valve in the lower hydraulic oil main is closed to stop the lowering of the piston in the hydraulic cylinder, and in addition, the check valve in the upper hydraulic oil pipe is closed to stop the hydraulic oil from flowing into the hydraulic cylinder. The gist is that the descent of the elevating member can be stopped by blocking the inflow into the elevating member.

Next, an embodiment of this invention will be described below based on the drawings.

In the figure, 1 and 2 are first and second hydraulic cylinders, which are upper chambers 1a and 2a and lower chamber 1, respectively.
b, 2b. 3 is an elevating member connected to the operating rods of the hydraulic cylinders 1 and 2;
is the load. 5 is an upper hydraulic oil pipe connected to upper chambers 1a and 2a of the first and second hydraulic cylinders 1 and 2. First and second lower hydraulic oil branch pipes 6, 7 are connected to the lower chambers 1b, 2b of the first and second hydraulic cylinders 1, 2, respectively,
The first and second lower hydraulic oil branch pipes 6 and 7 are combined to form a lower hydraulic oil main pipe 8.

Check valves 9, 10, 1 with pilot opening/closing mechanisms are installed in the upper hydraulic oil pipe 5, the first and second lower hydraulic oil branch pipes 6, 7, and the lower hydraulic oil main pipe 8, respectively.
1 and 12 are provided. The check valve with a pilot opening/closing mechanism is opened in both forward and reverse directions when it receives a certain hydraulic oil pressure. A pilot line 12 is formed between the check valve 9 in the upper hydraulic oil pipe 5 and the lower hydraulic oil main pipe 8,
The pressure in the lower hydraulic oil main pipe 8 acts on the check valve 9, and when the pressure is above a certain value, the check valve 9 is in an open state, allowing the flow downward in the figure to pass through without being hindered. Also, the check valve 10 in the first lower hydraulic oil branch pipe 6 and the second lower hydraulic oil branch pipe 7
A pilot line 13 is formed between the check valve 11 in the second lower hydraulic oil branch pipe 7 and the first lower hydraulic oil branch pipe 6. A pilot line 14 is formed between the check valve 11 in the second lower hydraulic oil branch pipe 7 and the first lower hydraulic oil branch pipe 6.

Furthermore, the check valve 2 in the lower hydraulic oil main pipe 8
A pilot line 23 is formed between 2 and the upper hydraulic oil pipe 5.

Reference numeral 15 denotes an electromagnetically driven switching valve as an oil passage switching means, which is operated according to each of the lowering process as the first operating process, the holding process as the second operating process, and the ascending process as the third operating process. , the upper hydraulic oil pipe 5 and the lower hydraulic oil main pipe 8, and the hydraulic power source 16.
and the tank 17 are selectively communicated with each other.

Reference numeral 18 denotes a counterbalance valve, which is installed in the lower hydraulic oil main pipe 8 and connects the lower hydraulic oil main pipe 8 to the tank 17 only when a pressure higher than a certain pressure is applied by the pilot line 19 from the upstream side. By keeping the inside of the lower hydraulic oil main pipe 8 at a constant pressure during the normal descending process, pressure is generated through the pilot line 12 to open the check valve 9.

In addition, 20 is a bypass line, which serves as a backflow oil path for hydraulic oil in the ascending process, and is connected to the check valve 2.
1 to bypass the counterbalance valve 18. The counterbalance valve 18, pilot line 19, bypass line 20, and check valve 21 constitute a hydraulic oil backpressure applying means.

In the above configuration, in the lowering step which is the first operation step, the upper hydraulic oil pipe 5 is connected to the hydraulic oil source 16 by the electromagnetically driven switching valve 15, and the lower hydraulic oil main pipe 8
are communicated with the tank 17, respectively.

At this time, the check valve 9 is activated by the pressure in the lower hydraulic oil main pipe 8, the check valve 22 is activated by the pressure in the upper hydraulic oil pipe 5, and the check valve 10 is activated by the pressure in the second lower hydraulic oil branch pipe 7. Due to the pressure, the check valve 11 closes the pilot lines 12, 23, 1, respectively, due to the pressure in the first lower hydraulic oil branch 6.
3 and 14 to open state.

Therefore, the hydraulic oil from the hydraulic source 16 flows into the upper chambers 1a, 2a of the first and second hydraulic cylinders 1, 2 through the upper hydraulic oil pipe 5, and lowers the elevating member 3. The hydraulic oil in the lower chambers 1b and 2b flows out into the first and second lower hydraulic oil branch pipes 6 and 7, respectively, and joins the lower hydraulic oil main pipe 8, and is connected to the counterbalance valve 18.
It flows out into tank 17 through .

In the ascending step, which is the second operation step, the electromagnetically driven switching valve 15 is switched to move the upper hydraulic oil pipe 5
to the tank 17, and the lower hydraulic oil main pipe 8 to the hydraulic source 16.
communicate with each other. Then, the hydraulic oil from the hydraulic source 16 flows into the lower hydraulic oil main pipe 8, passes through the bypass line 20, and flows into the first and second lower hydraulic oil branch pipes 6, 7.
branched into first and second hydraulic cylinders 1 and 2;
flows into the lower chambers 1b, 2b of 1 and raises the elevating member 3.

On the other hand, the hydraulic oil in the upper chambers 1a, 2a flows out into the upper hydraulic oil pipe 5, passes through the check valve 9, and then flows into the tank 1.
Released on 7th.

In addition, in the holding step, which is the third operation step, the electromagnetically driven switching valve 15 is operated to connect the upper hydraulic oil pipe 5 and the lower hydraulic oil main pipe 8 to both the hydraulic power source 16 and the tank 17. By cutting off the lifting member 3, the lifting member 3 is held in a fixed position.

Subsequently, in the lowering process, the lower hydraulic oil main pipe 8
The operation of stopping the elevating member 3 when the hydraulic oil leaks due to breakage or the like in the branch pipes 6 and 7 will be described below.

When hydraulic oil leaks from the lower hydraulic oil main pipe 8, the pressure within the lower hydraulic oil main pipe 8 decreases, and the pressure acting on the check valve 9 with a pilot opening/closing mechanism via the pilot line 12 decreases. , the check valve 9 is closed, and the supply of hydraulic oil from the hydraulic source 16 to the hydraulic cylinders 1 and 2 is cut off.

As a result of the above operation, the pressure in the upper hydraulic oil pipe 5 is reduced, and the pressure acting on the check valve 22 in the lower hydraulic oil main pipe 8 through the pilot line 23 is also reduced, so that the check valve 22 is closed.

At this time, the first and second lower hydraulic oil branch pipes 6,
Of course, the check valves 10 and 11 in 7 remain open.

In this way, when hydraulic oil leaks into the lower hydraulic oil main pipe 8, the check valve 22 in the main pipe 8 closes, and the lower chambers 1b, 2b of the hydraulic cylinders 1, 2 are closed.
Since the check valve 9 in the upper hydraulic oil pipe 5 is closed and the supply of hydraulic oil to the upper chambers 1a and 2a of the hydraulic cylinders 1 and 2 is also interrupted, the elevating member 3 is held in a fixed position without falling.

Next, if there is a leak in the first lower hydraulic oil branch pipe 6, the check valve 10 in the branch pipe 6 will remain open due to the pressure in the second lower hydraulic oil branch pipe 7 via the pilot line 13. However, the check valve 11 in the branch pipe 7 closes because the pressure from the first lower hydraulic oil branch pipe 6 via the pilot line 14 decreases.

Since the lower hydraulic oil main pipe 8 is connected to the low pressure in the first lower hydraulic oil branch pipe 6 via the open check valves 22 and 10, the check valve 9 in the upper hydraulic oil pipe 5 is When closed, the supply of hydraulic oil to the hydraulic cylinders 1 and 2 is stopped.

When the check valve 9 closes, the pressure in the upper hydraulic oil pipe 5 immediately becomes low, so the pressure in the pilot line 23 also decreases, and the check valve 2 in the lower hydraulic oil main pipe 8 becomes low in pressure.
2 is closed again, but even if the valve 22 is closed again, the lower hydraulic oil main pipe 8, which has once been reduced in pressure, remains at a low pressure, so the check valve 9 is maintained in the closed state.

Further, if there is a leak in the second lower hydraulic oil branch pipe 7, the check valve 10 closes by the opposite operation to the above, and the check valve 11 remains open.
The pressure of the lower hydraulic oil main pipe 8 is equalized with that of the second lower hydraulic oil branch pipe 7, and the pressure becomes low.

Thus, the check valve 9 in the upper hydraulic oil pipe 5 is closed and the supply of hydraulic oil to the hydraulic cylinders 1 and 2 is stopped.

In this way, the first and second lower hydraulic oil branch pipes 6, 7
If hydraulic fluid leaks from one of the two branch pipes, the check valve in the other branch pipe closes, blocking the flow of hydraulic fluid from the lower chamber of the hydraulic cylinder to which the branch pipe is connected. Since the check valve 9 in the hydraulic cylinder 5 is closed and the supply of hydraulic oil is also cut off, the elevating member 3 is supported by one of the hydraulic cylinders and is held at a fixed position without falling.

On the other hand, in the case where there is a leak in the lower hydraulic oil main pipe 8 and its branch pipes 6 and 7 during the holding process,
Each check valve 9, 22, 10, 11 operates in the same manner as described above.

That is, if there is a leak in the lower hydraulic oil main pipe 8, the check valve 22 in the main pipe 8 closes, thereby blocking the flow of the hydraulic oil in the lower chambers 1b, 2b of each hydraulic cylinder 1, 2. This prevents the elevating member 3 from descending due to its own weight.

Furthermore, if there is a leak in the first lower hydraulic oil branch pipe 6, the check valve 11 in the second lower hydraulic oil branch pipe 7 closes, so that the outflow of the hydraulic oil in the lower chamber 2b of the second hydraulic cylinder 2 is blocked. The cylinder 2 prevents the elevating member 3 from descending due to its own weight.

Even if there is a leak in the second lower hydraulic oil branch pipe 7,
In the same manner as described above, the first hydraulic cylinder 1 prevents the elevating member 3 from descending.

As described above, according to this invention, check valves with pilot opening/closing mechanisms are provided in the upper hydraulic oil pipe, the lower hydraulic oil main pipe, and the first and second lower hydraulic oil branch pipes, and each of the check valves and the lower hydraulic oil main,
Pilot lines were formed between the upper hydraulic oil pipe and the first and second lower hydraulic oil branch pipes, so
If hydraulic oil leaks due to damage to either the lower hydraulic oil main pipe or the first and second lower hydraulic oil branch pipes, the check valve of either the lower hydraulic oil main pipe or the branch pipe will be automatically activated. By closing the hydraulic cylinder to shut off the flow of hydraulic oil from the lower chamber of the hydraulic cylinder, and at the same time close the check valve in the upper hydraulic oil pipe to cut off the supply of hydraulic oil from the hydraulic source, the lifting member can be operated. It can be stopped and held in a fixed position, preventing inconveniences caused by leakage of hydraulic oil, especially rapid descent of the lifting member during the lowering process, ensuring worker safety, and further improving work efficiency. This has the excellent effect of avoiding damage to members.

In addition, there is no need to apply an unbalanced force to the hydraulic cylinder, unlike in the conventional example where a solenoid valve is used to shut off the check valve in the upper hydraulic oil pipe.
No equipment damage occurs.

Furthermore, in order to prevent leakage of hydraulic oil from the hydraulic cylinder during the holding process, the elevating member does not descend due to its own weight, unlike the conventional example using the solenoid valve described above. A similar effect is achieved.

In addition, the structure is simple, just installing a check valve with a pilot opening/closing mechanism and forming a pilot line, so the conventional lifting mechanism can be used as is, and it can be easily implemented with only minor changes to the hydraulic oil piping system. There is a practical benefit to being able to do this.

[Brief explanation of the drawing]

The figure is a schematic explanatory diagram showing an embodiment of this invention. 1, 2...Hydraulic cylinder, 1a, 2a...Upper chamber, 1b, 2b...Lower chamber, 3...Elevating member,
5...Upper hydraulic oil pipe, 6...First lower hydraulic oil branch pipe, 7...Second lower hydraulic oil branch pipe, 8...Lower hydraulic oil main pipe, 9, 10, 11, 22...With pilot opening/closing mechanism Check valve, 12, 13, 14, 23...
...Pilot line, 15...Electromagnetic drive switching valve,
16... Hydraulic power source, 17... Tank, 18... Counter balance valve.

Claims (1)

[Claims for Utility Model Registration] First and second hydraulic cylinders 1 and 2, an upper hydraulic oil pipe 5 that communicates the upper chambers 1a and 2a of the hydraulic cylinders with an oil passage switching means 15, and a lower chamber of the hydraulic cylinders. 1b, a second lower hydraulic oil branch pipe 7 that communicates with the lower chamber 2b of the hydraulic cylinder, and the first and second lower hydraulic oil branch pipes 6 and 7 join together. , a lower hydraulic oil main pipe 8 that communicates with the oil passage switching means 15, a hydraulic oil source 16, and a tank 17. In the first operation step, the oil pressure source 16 is connected to the upper hydraulic oil pipe 5, and the tank 17 are communicated with the lower hydraulic oil main pipe 8, and in the second operation step, the hydraulic pressure source 16 and the tank 17 are disconnected from the upper hydraulic oil pipe 5 and the lower hydraulic oil main pipe 8, and the third In the operation step, in a protection device for a hydraulic lifting mechanism that includes an oil passage switching means 15 that communicates the hydraulic source 16 with the lower hydraulic oil main pipe 8 and the tank 17 with the upper hydraulic oil pipe 5, respectively. , a first check valve 9 with a pilot opening/closing mechanism inserted into the upper hydraulic oil pipe 5 in a direction to prevent hydraulic oil from flowing from the hydraulic source 16; A second check valve 22 with a pilot opening/closing mechanism is inserted in a direction to prevent the flow of hydraulic fluid to the hydraulic source 16, and a third pilot opening/closing mechanism is inserted in the first lower hydraulic oil branch pipe 6 in a direction to prevent hydraulic fluid from flowing to the hydraulic source 16. a fourth check valve 11 with a pilot opening/closing mechanism inserted into the second lower hydraulic oil branch pipe 7 in a direction that prevents hydraulic oil from flowing to the hydraulic source 16; The hydraulic oil is inserted between the second check valve with pilot opening/closing mechanism 22 and the oil passage switching means 15, and is communicated with the tank 17 by the oil passage switching means 15 in the first operation step. Hydraulic oil back pressure applying means 18, 19, 20, and 21 are attached to the main pipe 8 for applying the hydraulic oil back pressure necessary for the opening operation of the first check valve 9 with a pilot opening/closing mechanism. The pilot line 12 from the check valve with pilot opening/closing mechanism 9 connects to the second check valve with pilot opening/closing mechanism 22 and the hydraulic oil back pressure applying means 1.
Lower hydraulic oil main pipe 8 between 8, 19, 20, 21
The pilot line 23 from the second check valve with pilot opening/closing mechanism 22 is connected to the upper hydraulic oil pipe 5 between the first check valve with pilot opening/closing mechanism 9 and the upper chambers 1a, 2a of the hydraulic cylinders 1, 2. The pilot line 13 from the third check valve with pilot opening/closing mechanism 10 is connected to the second lower chamber between the lower chamber 2b of the second hydraulic cylinder 2 and the fourth check valve with pilot opening/closing mechanism 11. Oil branch pipe 7
The pilot line 14 from the fourth check valve 11 with a pilot opening/closing mechanism is connected to the first lower chamber 1b of the first hydraulic cylinder 1 and the third check valve 10 with a pilot opening/closing mechanism. Oil branch pipe 6
A protective device in a hydraulic lifting mechanism, characterized in that it is connected to.