JPS6131232Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a differential shutoff valve for an automobile lift.

As a lift for large automobiles that has been used conventionally, one of the two lifts that rise and fall in synchronization is moved to adjust the width between the two lifts according to the length of the automobile body. There are some things you can use. In this case, the hydraulic circuit that supplies the mobile lift needs to be flexible, and pressure-resistant hoses are used for this purpose, but if the hose breaks or comes off, the lift will plummet, resulting in a major accident. . Therefore, in order to prevent such accidents from occurring, safety devices are installed, and one example of this is to equip the hydraulic cylinder of the lift with a shut-off valve that automatically closes in the event of an abnormality. When an abnormal situation like the one mentioned above occurs, the pressure on the hydraulic pump side of the automatic shut-off valve suddenly drops, creating a large pressure difference between the front and back of the automatic shut-off valve, and this pressure difference is used to shut down the valve instantly. It is said that it will be closed.

However, such conventional valves are of the so-called direct-acting type, and when the lift is lowered, the entire pressure of the reverse flow is applied to the valve body, and the valve body attempts to close the flow path of the valve. However, if the flow passage closes when the lift is lowered normally, the lift will no longer function, so a spring that always presses the valve body in one direction is used to prevent the flow passage from closing even when the lift is lowered. It's equipped. This spring must be used with a pushing force greater than the total pressure applied to the valve body when the lift is lowered as mentioned above, so it must be extremely strong, and this makes it difficult to manufacture shut-off valves. It involved a huge disadvantage. Additionally, if the valve closes automatically in the event of an abnormality, the flow path is instantly blocked, and a large impact pressure of hydraulic pressure is generated on the valve and on the lift side from the valve, resulting in damage to the valve itself and various equipment on the lift side from the valve. There was also a fear that this would occur. To solve the former problem, it is necessary to use a physically strong material such as cast steel for the shutoff valve body, and the finish must be precisely polished, etc., and these disadvantages are This further increases the disadvantages of Particularly for large-diameter ones, the flow rate becomes large, and a direct-acting type cannot physically withstand it and lacks durability. Even if there is a product that solves the problem of durability, it still does not solve the problem of the above-mentioned destruction caused by the above-mentioned impact pressure.

The present invention was devised in view of the above-mentioned circumstances, and provides a differential shutoff valve that eliminates the disadvantages and problems of the conventional devices by effectively utilizing the differential system. It is in.

An embodiment of the present invention will be described below with reference to the accompanying drawings. Reference numeral 1 denotes a movable lift, and the lift 1 is paired with another fixed lift (not shown) to form a twin lift device for lifting a large vehicle. It is. The lift 1 is equipped with the differential shutoff valve 2 of the present invention, one end of which is connected to a pressure-resistant rubber hose 3, and the other end of the pressure-resistant rubber hose 3 connected to a hydraulic pump (not shown). The other opening of the differential shutoff valve 2 communicates with the cylinder 5 of the lift 1 via a pipe 4 or the like.

Details of the differential shutoff valve 2 are shown in FIGS. 2 and 3. In the figure, reference numeral 6 denotes an outer cylinder, and communication ports 7 and 8 are formed at both upper and lower ends of the outer cylinder 6, respectively, and a flange 9 is provided on the inner wall of the upper and lower central portions. 10 is an inner cylinder;
The lower surface of 0 is open, the lower circumferential portion thereof is tightly fixed to the flange 9, the upper surface is closed by an upper lid 11, and an appropriate number of communication holes 12 are bored in the lower side surface. It has been set up. A valve body 13 that slides vertically within the inner cylinder 10 is installed inside the inner cylinder 10, and flanges 14, 15 are provided at the upper and lower ends of the valve body 13.
The outer circumferential surface of the upper flange 14 is in sliding contact with the inner wall surface of the inner cylinder, and the lower flange 15 is shaped like a flange 9 as the valve element 13 moves up and down.
It is configured so that it is dissociated with. A convex portion 16 is formed in the lower part of the valve body 13, and the convex portion 16 is
Lower inner cylinder 17 whose top surface is open and whose bottom surface is closed
It is something that slides inside and appears. The lower inner cylinder 17 is fixed to the outer cylinder 6 via a support member 18 and the like, and the inside of the inner cylinder 17 communicates with the outside of the outer cylinder 6 through a through hole 19 at its lower bottom. A through hole 20 running vertically in the center of the valve body 13
A partition member 21 is fitted into the intermediate portion of the through hole 20 to divide the through hole 20 into two upper and lower chambers 20a and 20b. The chamber 20b is communicated with the inside of the inner cylinder 10 through a communication hole 22 formed in the valve body 13. In addition, when the valve body 13 moves upward, the outer cylinder 6 is attached to the convex portion 16.
A communication hole 23 communicating with the inside of the chamber 20b is formed, and the communication hole 23 and the chamber 20b communicate with each other through an opening 20' formed at the bottom of the chamber 20b. ' is a valve 25 that normally closes the opening 20' under the pressure of a spring 24.
be installed. Further, an opening 26 is bored in the center of the upper lid 11 of the inner cylinder 10, and a nozzle 27 is mounted upward in the opening 26. Furthermore, the inner cylinder 1
0 is equipped with a spring 28, one end of which abuts against the partition member 21 to constantly press the valve body 13 in the direction of the flow opening 8, that is, in the downward direction in the figure.

Next, the above action will be described. To raise the lift, oil pumped by a hydraulic pump is forced into the flow port 7 through the pressure-resistant rubber hose 3. The oil press-fitted into the flow port 7 passes through a flow path 29 formed between the outer cylinder 6 and the inner cylinder 10 and flows into the inner cylinder 10 through the flow hole 12. Normally, the valve body 13 is pushed down by the pushing force of the spring 28 as shown in FIG. 6 and lower inner cylinder 1
7, flows through the flow path 30, flows out from the flow port 8, and flows into the cylinder 5.
, and the lift 1 rises. The direction of oil flow when the lift 1 is lowered is simply the opposite of the flow direction when the lift 1 is raised, and the position of the valve body 13 remains unchanged. In this case, the direction of oil flow is reversed and the nozzle 2
Although a suction force is generated in the valve body 7 and tries to push the valve body 13 toward the flow port 7 side, the spring 28 prevents the valve body 13 from moving.

Next, if the pressure-resistant rubber hose 3 breaks or comes off and the oil pressure on the flow port 7 side suddenly drops, or if the flow rate of oil becomes abnormally fast when the lift 1 is lowered and a dangerous situation occurs, the nozzle The suction force of 27 increases accordingly, pushing the valve body 13 up toward the flow port 7 against the pushing force of the spring 28. As a result, the flange 15 of the valve body 13 comes into close contact with the flange 9 to block and block the flow passages 30 and 29', and the oil on the side of the flow port 8 becomes sealed and stops in that state.
Lowering of the lift 1 is automatically prevented.

Incidentally, when the flow passages 30 and 29' are shut off, the flow of oil immediately stops, and a large impact pressure is generated on the flow port 8 side at that moment. In such a case, the impact pressure is applied to the valve 25 from the communication hole 23 to push the valve 25 up against the pressure of the spring 24 and open the opening 2.
0' is opened, and the oil passes through the opening 20', flows into the chamber 20b, and further passes through the communication hole 22, the flow path 29', the flow hole 12, the flow path 29, etc., to the flow port 7 side. When the impact pressure decreases, the valve 25 is pushed down by the pressure of the spring 24, and the opening 20' is closed again.

The present invention is as described above, and the convex part formed integrally with the valve body is slidably fitted into the lower inner cylinder that communicates with the outside air, so that when the oil flows from the bottom to the top, that is, the lift is lowered. In the direction of oil flow, only the lower surface of the convex portion receives no hydraulic pressure. Therefore, even if the spring is weak, it is possible to push down the valve body by the pressure difference.

Furthermore, since the impact pressure when the flow path is blocked or blocked in an abnormal situation is released from the valve provided on the valve body, this will not damage the differential shutoff valve itself or the equipment on the lift side.

Furthermore, as mentioned above, it has a differential structure,
Since there is no physical stress on the whole, it is possible to seal each part with ordinary gaskets, and there is no need for special polishing, which is advantageous for large-diameter items, and the materials are ordinary steel pipes. This has the advantage of simplifying the production of the shutoff valve.

[Brief explanation of the drawing]

Figure 1 is a front view showing the differential shutoff valve of the present invention installed on a lift, Figures 2 and 3 are cross-sectional views of the differential shutoff valve of the present invention, and Figure 2 shows the valve body pushed down. indicates that the flow path is in communication,
FIG. 3 shows a state in which the valve body is pushed up and the flow path is closed. Explanation of symbols, 6... Outer cylinder, 13... Valve body, 16
... Convex portion, 17 ... Lower inner cylinder, 19 ... Through hole, 2
4... Spring, 25... Valve body.

Claims (1)

[Scope of utility model registration request] The valve body is normally pressed in one direction by the pushing force of a spring to open the flow passage, and when an abnormally large pressure difference occurs between the front and rear of the valve body, the valve body is slid to open the flow passage. A convex portion 16 is provided integrally with the valve body 13, and the convex portion 16 is slidably fitted into a lower inner cylinder 17, and the lower inner cylinder 17 is transparent. It communicates with the outside of the outer cylinder 6 through the hole 19, and the valve body 13 is normally closed by the pushing force of the spring 24, and is opened only when abnormally high impact pressure occurs in the lift side circuit. A differential shutoff valve for an automobile lift, which is provided with a valve body 25.