JP3169261U - Telescopic mechanism - Google Patents

Abstract

An expansion / contraction mechanism that suppresses the fluffy feeling of an expansion / contraction mechanism using an air spring is provided. A telescopic mechanism 10 is configured by connecting an air spring 20 and an air cylinder 30 in parallel. In the air spring 20, a cylindrical bellows 23 made of an elastic body is disposed between the upper surface plate 21 and the lower surface plate 22. In the air cylinder 30, a cylinder sleeve 31 fixed to the lower surface plate 22 and a piston rod 32 pass through the bellows 23 and are fixed to the upper surface plate 21. The air spring 20 and the air cylinder 30 are respectively provided with a valve 41 and a valve 42 for sending compressed air. When the valves 41 and 42 are closed, the air chamber 24 of the air spring 20 and the air chamber 36 of the air cylinder 30 are provided. It becomes a sealed space independent from each other. [Selection] Figure 2

Description

The present invention relates to an expansion / contraction mechanism, and more particularly to an expansion / contraction mechanism suitable for use in a table lifter suitable for installation in a clean room.

For example, as shown in Patent Document 1, the table lifter connects the top plate and the bottom frame so as to be close to and away from each other by an arm. As a means for operating the arm, a hydraulic cylinder disposed in the arm is used, and the top plate is moved up and down by extending and contracting the hydraulic cylinder. However, the hydraulic cylinder cannot be installed in a clean room such as a semiconductor factory because oil scatters from a joint connecting an oil path, a piston rod exposed from the inside of the cylinder, or the like.

If the expansion and contraction operation is performed using air pressure instead of oil pressure, contamination by oil can be suppressed, so use of a pneumatic cylinder using air pressure or a bellows type air spring (for example, Patent Document 2) in the clean room is considered. Has been.
In addition, although patent document 3 is a technique regarding the air spring utilized for the isolation structure with respect to an earthquake, in order to prevent the horizontal swing in an air spring, the example which has arrange | positioned in the bellows is disclosed.

Utility model registration No. 3076765 JP 2004-256256 A JP-A-6-42158

However, since air is compressible, it cannot produce much force. Further, since the pressure cannot be increased as much as the hydraulic pressure, the pneumatic cylinder has a weaker force than the hydraulic cylinder, and the hydraulic cylinder cannot be simply replaced. On the other hand, the air spring shown in Patent Document 2 is stronger than the air cylinder because it raises the top plate in a wider area than the air cylinder, but the air chamber of the air spring has a large volume and is made of elastic rubber. The whole room is made and widens in the horizontal direction. For this reason, although the cushioning property with respect to vibration is good, the cushioning property causes a fluffy state, which is not very suitable for use in a table lifter that wants to maintain a stationary state.

An object of the present invention is to provide an expansion / contraction mechanism that suppresses the fluffy feeling while being an expansion / contraction mechanism using an air spring.

In order to solve the above problems, the telescopic mechanism of the present invention includes an air spring in which a cylindrical bellows made of an elastic body is disposed between an upper surface plate and a lower surface plate to form an air chamber, and a cylinder sleeve is fixed to the lower surface plate. An air cylinder in which a piston rod extended from a piston head in the cylinder sleeve passes through the center of the bellows and is fixed to the upper plate, a valve for sending compressed air to the air spring, and compressed air to the air cylinder And when the two valves are closed, the air chamber and the air chamber in the cylinder sleeve form a sealed space independent of each other.

It is a perspective view of a table lifter. It is sectional drawing of an expansion-contraction mechanism. It is sectional drawing of another Example. It is sectional drawing of another Example. It is sectional drawing of another Example.

Embodiments will be described below with reference to the drawings.
FIG. 1 is a perspective view of a table lifter 1 according to the present embodiment.
In the table lifter 1, a top plate body 2 and a bottom frame 3 provided to face the top plate body 2 are connected by an arm 4 so as to be close to and away from each other. The arm 4 is obtained by connecting a frame-shaped link 5 and a link 6 with a rotation shaft 7 at the center position thereof. One end 5 a of the link 5 pivotally supports the top plate 2, and the other end 5 b is provided with a roller 8 a that rolls on the bottom frame 3. On the other hand, one end 6a of the link 6 supports the top plate 2 with a roller 8b, and the other end 6b pivotally supports the bottom frame 3.

In the middle of the length of the link 6, the rod 9 a is connected to the left and right of the link 6, and the link 6 is pivotally supported by using the head 10 a rod 9 a of the telescopic mechanism 10 as a support shaft. The base portion 10 b of the telescopic mechanism 10 is pivotally supported by a bearing 9 c provided on the beam 9 b passed to the end portion 5 b of the link 5. The expansion / contraction mechanism 10 changes the distance between the head portion 10a and the base portion 10b, whereby the link 5 and the link 6 rotate in directions opposite to each other about the rotation shaft 7 to raise and lower the top plate 2.

The telescopic mechanism 10 is a composite body in which an air cylinder 30 is inserted in the center of the air spring 20, and the air spring 20 and the air cylinder 30 exist between the head portion 10a and the base portion 10b in parallel. In FIG. 2, the cross section of the expansion-contraction mechanism 10 is shown. In the air spring 20, a cylindrical bellows 23 made of elastic rubber is provided between a circular upper surface plate 21 and a lower surface plate 22 to form an air chamber 24. In the middle of the length of the bellows 23, an intermediate ring 25 is provided to restrict the widening of the bellows 23 and has a bellows-like appearance. In some cases, the intermediate ring 25 is not provided, and in this case, it is exclusively a sleeve. Compressed air to the air chamber 24 is injected through an air supply port 26 provided in the lower surface plate 22. On the other hand, in the air cylinder 30, a metal cylinder sleeve 31 is fixed perpendicularly to the center of the lower surface plate 22, and the inner diameter of the cylinder sleeve 31 is smaller than the diameter of the lower surface plate 22. A piston rod 32 extended from the piston head 33 in the cylinder sleeve 31 is fixed to the center of the upper surface plate 21 through the center of the cylindrical bellows 23. A double ring seal 34 is provided on the piston head 33 disposed in the air chamber 36 in the cylinder sleeve 31. An air supply port 35 is provided in the air cylinder 30 separately from the air supply port 26 of the air spring 20. A head portion 10 a having a shaft hole h with the rod 8 as a support shaft is fixed to the upper surface plate 21. Since the head 10 a receives a load, the position thereof is arranged on the extension of the piston rod 32. A base portion 10b having a shaft hole g supported by a bearing 9c (FIG. 1) is fixed below the cylinder sleeve 31. Accordingly, the air cylinder 30 is positioned on a straight line connecting the point of application of the load (head 10a) and the fulcrum (base 10b). The air spring 20 is also arranged on the straight line because the air cylinder 30 passes through the center of the air spring 20. In FIG. 2, P is a generation source of compressed air, and shows a state where the piston rod 32 is raised.

The air supply ports 26 and 35 of the air spring 20 and the air cylinder 30 are respectively provided with separate valves 41 and 42 and connected to a common compressed air generation source P. The valves 41 and 42 are normally closed and are in an air supply state in which compressed air is injected into the air spring 20 or the air cylinder 30 and an exhaust state in which compressed air is discharged from the air spring 20 or the air cylinder 30 to the atmosphere. Can take two states. In the air chamber 36 of the cylinder sleeve 31, a space located above the piston head 33 is open to the atmosphere. In the drawing, the valves 41 and 42 are connected to a common compressed air generation source P, but may be another generation source P ′. In this case, when injecting air into the air spring 20 and the air cylinder 30, the air chamber 24 and the air chamber 36 are connected to separate compressed air generation sources P and P ′, and supplied with different compressed air. The In any case, in the closed state, the air chamber 24 and the air chamber 36 need to be sealed spaces independent of each other.

When the valves 41 and 42 are changed from the closed state to the air supply state, air is sent from the compressed air generation source P to the air spring 20 and the air cylinder 30. The air spring 20 and the air cylinder 30 increase the distance between the lower surface portion 22 and the upper surface portion 21 equally. The links 6 and 7 stand up, and the top plate 2 rises. At this time, since the air chamber 24 of the air spring 20 has a larger capacity than the air chamber 36 of the air cylinder 30, the top plate 2 is lifted solely by the lifting force of the air spring 20. When the piston head 33 of the air cylinder 30 reaches the upper limit height, the valves 41 and 42 are closed. By making the closed state, the air chamber 24 of the air spring 20 having a large capacity and the air chamber 36 of the air cylinder 30 having a capacity smaller than the air chamber 20 become independent spaces.

In this state, when the load of the top plate 2 fluctuates, the air spring 20 sinks or rises due to the load variation due to the expansion of the volume around the bellows 23 and the large volume of the internal air. This amount is negligible but causes a so-called fluffy feeling. On the other hand, since the air chamber 36 of the air cylinder 30 has a small capacity, the volume fluctuation of the internal air is smaller than that of the air spring 20 and the metal cylinder sleeve 31 does not widen, so that it is harder than the air spring 20. Therefore, the fluffy feeling caused by the air spring 20 is suppressed.
In addition, the air cylinder 30 serves as a guide, and the horizontal deflection of the air spring 20 is suppressed.

When the top plate 2 is lifted in a state where no load is applied and then a load is applied, the air spring 20 tends to sink due to widening and volume fluctuation around the bellows 23, but this operation is performed by the air cylinder 30. Suppressed and sinking is less than when only the air spring 20 is used.

On the other hand, when the load is removed by raising the load while the load is applied, the piston head 33 has reached the upper limit of the cylinder, and therefore no jumping occurs due to the loss of the load. When the valves 41 and 42 are in the exhaust state, the gas in the air spring 20 and the air cylinder 30 is released to the atmosphere, and the top plate 2 is lowered.

The links 6 and 7 of the arm 4 have the same vertical length around the axis of the rotation shaft 7, and the top plate 2 is always moved parallel to the bottom frame 3. Further, since the air spring 20 and the air cylinder 30 are arranged in parallel in a straight line connecting the acting point and the fulcrum to which the load is applied, the air spring 20 and the air cylinder 30 can similarly support the load. The range required for installation may be the range required for the air spring 20.

In the above embodiment, an air spring in which a cylindrical bellows made of an elastic body is disposed between an upper surface plate and a lower surface plate to form an air chamber, and a cylinder sleeve is fixed to the lower surface plate, and a piston head in the cylinder sleeve A piston rod extended from the bellows through the center of the bellows and fixed to the top plate, a valve for sending compressed air to the air spring, and a valve for sending compressed air to the air cylinder, A valve for sending compressed air to the air spring and a valve for sending compressed air to the air cylinder are arranged in parallel, and when the two valves are closed, the air chamber and the air chamber in the cylinder sleeve are independent of each other. It was set as the sealed space.
However, even if the valve for sending compressed air to the air spring and the valve for sending compressed air to the air cylinder are arranged in series, the air chamber and the air chamber in the cylinder sleeve should be independent from each other. Can do.

FIG. 3 shows an embodiment in this way. A description of what is common to FIG. 2 will be omitted. A difference from the embodiment of FIG. 2 is that the valve 41 is connected to the air port 26 of the air spring 20 and the valve 42. In this embodiment, when compressed air is injected, the air chamber 24 of the air spring 20 and the air chamber 36 of the air cylinder 30 are connected in common, and the air chambers are mutually connected when the valves 41 and 42 are closed. It is common to have an independent sealed space.

FIG. 4 shows still another embodiment. A compressed air supply port 26a and an exhaust port 26b are provided on the lower surface plate 22, and the valve 41 is connected to the supply port 26a, and the air chamber 24 is connected to the exhaust port 26b. A path for compressed air is provided so as to reach the air chamber 36 of the air cylinder 30 via the. In this manner, the air chamber 24 of the air spring 20 may be once introduced into the air chamber 36 after the compressed air passes through. Also in this embodiment, when the valves 41 and 42 are closed, it is common that the air chambers 24 and 36 become sealed spaces independent of each other.

FIG. 5 shows an embodiment in which compressed air is once taken into the air chamber 24 and then introduced into the air chamber 36 of the air cylinder 30 as it is. In the present embodiment, a path directly connecting the air chamber 24 and the air chamber 36 is provided. In this path, a check valve (check valve) 42 ′ is provided between the air chamber 24 and the air supply port 35 b of the air cylinder 30 instead of the valve 42. Further, the valve 41 is changed to a valve 41 'having a function of only introducing compressed air. In the present embodiment, while the compressed air is introduced into the air chamber 24 via the air supply port 26, the air chamber 24 of the air spring 20 and the air chamber 36 of the air cylinder 30 are connected in common, Compressed air is sent from the air chamber 24 to the air chamber 36 by the check valve 42 ′. When the valve 41 ′ is closed, the check valve 42 ′ is also closed, and the air chambers 24 and 36 become a sealed space independent from each other. The check valve 42 ′ suppresses the backflow of air from the air chamber 36 to the air chamber 24. The valve 43 is a valve that exhausts compressed air from the exhaust port 35 a of the air cylinder 30. In the present embodiment, the valve 41 ′ may be the valve 41 having an exhaust function.

DESCRIPTION OF SYMBOLS 1 Table lifter 2 Top plate body 3 Bottom frame 10 Telescopic mechanism 20 Air spring 21 Upper surface plate 22 Lower surface plate 23 Bellows 24 Air chamber 30 Air cylinder 31 Cylinder sleeve 32 Piston rod 41 Valve 42 Valve

Claims (3)

An air spring in which a cylindrical bellows made of an elastic body is disposed between an upper surface plate and a lower surface plate to form an air chamber;
An air cylinder in which a cylinder sleeve is fixed to the lower surface plate, and a piston rod extended from a piston head in the cylinder sleeve is fixed to the upper surface plate through the center of the bellows;
A valve for sending compressed air to the air spring;
A telescopic mechanism comprising a valve for sending compressed air to the air cylinder, wherein the air chamber and the air chamber in the cylinder sleeve form a sealed space independent from each other when the two valves are closed. .
2. The expansion / contraction mechanism according to claim 1, further comprising a compressed air supply source for commonly supplying compressed air to the two valves.
2. The expansion / contraction mechanism according to claim 1, wherein a path from the air chamber of the air spring to the air chamber of the air cylinder is provided, and a check valve is provided in the path.