JP7010440B2 - Cylinder and lifting device - Google Patents

Description

The present invention relates to a cylinder and an elevating device, and more particularly to a cylinder having a retractable casing and an elevating device including the same.

As a conventional cylinder, a cylinder provided with a retractable casing is generally known. (For example, refer to Patent Documents 1 to 6 and the like). In each of these Patent Documents 1 to 6, the casing includes a plurality of cylinders connected in a telescope shape, and the casing is extended by supplying a fluid into the casing, and the fluid is discharged from the casing. It is stated that the casing is shortened.

U.S. Pat. No. 4,294,572 Japanese Unexamined Patent Publication No. 57-047006 U.S. Pat. No. 6,450,083 Microfilm of No. 50-071490 (No. 51-151887) Japanese Unexamined Patent Publication No. 2002-235709 Microfilm of Jitsugyo No. 63-162370 (Jitsukaihei 02-084005)

However, in the above-mentioned conventional cylinder, when the casing is extended, the innermost cylinder, which has a relatively large volume, is fully filled with fluid, and then the innermost cylinder moves with respect to other cylinders. start. Therefore, it takes time to extend the casing, and the amount of fluid for the operation increases.
Further, when the casing is shortened, if a large load is not applied to the innermost cylinder from the outside, it is difficult to shorten the casing or it takes time to shorten the casing.

The present invention has been made in view of the above situation, and an object of the present invention is to provide a cylinder capable of accelerating the extension operation of the casing and reducing the amount of fluid for operation, and an elevating device provided with the cylinder. ..

In order to solve the above problem, the invention according to claim 1 is a cylinder provided with a telescopic casing, wherein the casing includes a plurality of cylinders connected in a telescope shape, and the plurality of cylinders are provided. The innermost cylinder of the body is provided with a closing body so as to close the internal space of the cylinder, and the outermost cylinder of the plurality of cylinders is the cylinder of the cylinder. A first cap is provided so as to close the shaft end opening, and a variable volume space surrounded by the closing body and the first cap is formed in the casing, and a fluid is introduced into the variable volume space. The gist is that the casing is extended by supplying the casing, and the casing is shortened by discharging the fluid from the variable volume space.
The invention according to claim 2 is the invention according to claim 1, wherein the closing body is provided so as to close the internal space of the shaft end portion on the innermost tubular body near the first cap. The gist is that.
The invention according to claim 3 is the invention according to claim 1 or 2, wherein the fluid is a liquid, and the closing body is in the variable volume space when the liquid is supplied to the variable volume space. The gist is that a functional valve that separates air from the liquid that collects in the water and exhausts it to the outside is provided.
The invention according to claim 4 is characterized in that, in the invention according to claim 3, the functional valve is arranged on the surface side of the closing body that forms the volume variable space.
The invention according to claim 5 is the invention according to claim 1 or 2, wherein the innermost cylinder is provided with a second cap so as to close the shaft end opening of the cylinder. In the casing, a volume invariant space is formed which is surrounded by the closing body and the second cap and communicates with the volume variable space. The fluid is a liquid, and the second cap has the above. The gist is that a functional valve is provided that separates air from the liquid that collects in the volume invariant space and exhausts it to the outside when the liquid is supplied to the volume variable space.
The invention according to claim 6 is characterized in that, in the invention according to claim 5, the functional valve is arranged on the surface side of the second cap that forms the volume invariant space.
The invention according to claim 7 is the inner cylinder in the inner and outer cylinders adjacent to each other inside and outside of the plurality of cylinders in the invention according to any one of claims 1 to 6. A space is formed by the sealing material between the outer peripheral surface of the outer cylinder and the inner peripheral surface of the outer cylinder, and an opening for opening the space to the outside is provided on the outer cylinder side. The gist is that when the fluid is discharged from the variable volume space, the fluid flows into the space through the opening.
In order to solve the above problem, the invention according to claim 8 is an elevating device, and the gist is to include the cylinder according to any one of claims 1 to 7.

According to the cylinder of the present invention, the casing includes a plurality of cylinders connected in a telescope shape, and the innermost cylinder of the plurality of cylinders is closed so as to close the internal space of the cylinders. A body is provided, and a first cap is provided on the outermost cylinder of the plurality of cylinders so as to close the shaft end opening of the cylinder. A variable volume space surrounded by the closing body and the first cap is formed in the casing, and by supplying the fluid to the variable volume space, the casing expands and the fluid is discharged from the variable volume space. The casing is shortened. As a result, when the casing is extended, the innermost cylinder starts to move with respect to other cylinders by filling the variable volume space, which is a relatively small volume in the shortened state, with the fluid. Therefore, the extension operation of the casing can be accelerated, and the amount of fluid for operation can be reduced. Furthermore, when shortening the casing, even if a large load is not applied to the innermost cylinder from the outside, the casing can be made smooth and smooth by making the closing body heavier by setting the material, size, etc. It can be shortened quickly.

Further, when the closing body is provided so as to close the internal space of the shaft end portion on the side closer to the first cap in the innermost cylinder, the extension operation of the casing can be further accelerated. , The amount of fluid for operation can be further reduced.

Further, when the fluid is a liquid and the closing body is provided with a functional valve, air is separated from the liquid accumulated in the variable volume space by the functional valve when the casing is extended. Since it is exhausted to the outside, the pressure is applied only by the liquid, and the casing is stably extended. In addition, the functional valve can be easily attached to the innermost cylinder. Further, the thickness of the cap can be made compact and the height of the casing in the shortened state can be lowered as compared with the case where the cap closing the shaft end opening of the innermost cylinder is provided with a functional valve.

Further, when the functional valve is arranged on the surface side of the closing body that forms the volume variable space, the mountability of the functional valve is further enhanced.

Further, a second cap is provided on the innermost cylinder, a volume invariant space is formed in the casing, the fluid is a liquid, and a functional valve is provided on the second cap. If it is provided, when the casing is extended, the air is separated from the liquid accumulated in the volume invariant space by the functional valve and exhausted to the outside, so that the pressure is applied almost exclusively by the liquid, and the casing is extended. The operation is stable. Further, when the casing is extended, the liquid can be filled over the variable volume space and the invariant volume space in the casing.

Further, when the functional valve is arranged on the surface side of the second cap that forms the volume invariant space, the functional valve does not project to the outer surface of the second cap, and the second cap can be effectively used. .. For example, when the cylinder is used as an elevating device, the second cap can be effectively connected to the table constituting the elevating device.

Further, a space partitioned by a sealing material is formed between the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder, and the space is externally formed on the outer cylinder side. An opening is provided to open, and when the fluid is discharged from the variable volume space and the fluid flows into the space through the opening, the casing is opened by its own weight regardless of the load applied to the casing. It can be shortened smoothly and quickly.

According to the elevating device of the present invention, since the above-mentioned cylinder is provided, the object can be suitably raised and lowered by the operation of the cylinder.

The present invention will be further described in the following detailed description with reference to the plurality of references mentioned with reference to non-limiting examples of typical embodiments according to the invention, although similar reference numerals are in the drawings. Similar parts are shown through several figures.
It is a vertical sectional view of the hydraulic cylinder (the shortened state of a casing) which concerns on Example 1. FIG. It is a vertical sectional view of the said hydraulic cylinder (extended state of a casing). It is a perspective view of the hydraulic cylinder, (a) shows the shortened state of a casing, and (b) shows the extended state of a casing. It is explanatory drawing for demonstrating the operation (extension operation of a casing) of the said hydraulic cylinder. It is explanatory drawing for demonstrating the operation (extension operation of a casing) of the said hydraulic cylinder. It is explanatory drawing for demonstrating the operation (extension operation of a casing) of the hydraulic cylinder, (a) shows the air bleeding state by a functional valve, and (b) shows the completion state of the air bleeding by a functional valve. It is a vertical sectional view of the hydraulic cylinder which concerns on the modification 1 of Example 1. FIG. It is a vertical sectional view of the main part of the hydraulic cylinder which concerns on the modification 2 of Example 1. FIG. It is a vertical sectional view of the hydraulic cylinder (the shortened state of a casing) which concerns on Example 2. FIG. It is explanatory drawing for demonstrating the operation (extension operation of a casing) of the said hydraulic cylinder. It is explanatory drawing for demonstrating the operation (extension operation of a casing) of the said hydraulic cylinder. It is a vertical sectional view of the hydraulic cylinder which concerns on the modification 1 of Example 2. FIG. It is a vertical cross-sectional view of the hydraulic cylinder which concerns on the modification 2 of Example 2, (a) shows the shortened state of a casing, and (b) shows the extended state of a casing. It is explanatory drawing for demonstrating use (article elevating device) of the said hydraulic cylinder, (a) shows the descending state of an article, (b) shows the ascending state of an article. It is explanatory drawing for demonstrating another use (article elevating device) of the hydraulic cylinder, (a) shows the descending state of an article, (b) shows the ascending state of an article. It is explanatory drawing for demonstrating further other use (bathing assisting apparatus) of the said hydraulic cylinder. It is sectional drawing of the main part of the hydraulic cylinder which concerns on other forms. It is a perspective view of the main part of the cylinder which constitutes the said hydraulic cylinder. It is sectional drawing of the main part of the hydraulic cylinder which concerns on further another form, (a) shows the form which the hole forming an opening is formed in the ring member, (b) shows the form which forms an opening in a ring member. Shows the form in which the groove is formed.

The matters shown here are for illustrative purposes and embodiments of the present invention, and are the most effective and effortless explanations for understanding the principles and conceptual features of the present invention. It is stated for the purpose of providing what seems to be. In this regard, it is not intended to show structural details of the invention beyond a certain degree necessary for a fundamental understanding of the invention, and some embodiments of the invention are provided by description in conjunction with the drawings. It is intended to clarify to those skilled in the art how it is actually realized.

<Cylinder>
As shown in FIGS. 1, 2 and 9, for example, the cylinder according to the present embodiment is a cylinder (1A, 1B) provided with a retractable casing (2), and the casing (2) is a telescope. A plurality of cylinders (3, 4, 5) connected in a shape are provided, and the innermost cylinder (3) of the plurality of cylinders (3 to 5) closes the internal space of the cylinder. The casing (18, 34, 35, 39) is provided as described above, and the outermost cylinder (5) of the plurality of cylinders (3 to 5) is provided with a shaft end opening of the cylinder. A first cap (7) is provided so as to close the cap. A variable volume space (S1) surrounded by the closing body (18, 34, 35, 39) and the first cap (7) is formed in the casing (2), and the variable volume space (S1) is formed. The casing (2) is extended by supplying the fluid to the space, and the casing (2) is shortened by discharging the fluid from the variable volume space (S1).
The type of the fluid is not particularly limited, and it may be a liquid or a gas. From the viewpoint of convenience, this fluid is preferably water (particularly tap water).

The material, size, shape, number, etc. of the cylinders (3 to 5) are not particularly limited. The cylinders (3 to 5) can be made of, for example, synthetic resin or metal. Examples of the synthetic resin include polyolefin resin, polyester resin, polyamide resin, polyvinyl chloride resin, ABS resin, AES resin, AAS resin, fiber reinforced resin and the like. Of these, polyvinyl chloride resin, ABS resin, AES resin, and AAS resin are preferable in terms of moldability, rigidity, price, and the like, and polyvinyl chloride resin is particularly preferable. Examples of the metal include stainless steel and aluminum.

The material, size, shape, etc. of the first cap (7) are not particularly limited. The first cap (7) can be made of, for example, a synthetic resin or a metal. Examples of the synthetic resin or metal include the types exemplified by the material of the tubular body (3 to 5). Further, the first cap (7) may be formed with, for example, a port (21) for supplying and discharging a fluid to the variable volume space (S1).

The location, material, size, shape, etc. of the closing body (18, 34, 35, 39) are not particularly limited. The closing body (18, 34, 35, 39) can be formed, for example, in a shape that completely or partially closes the internal space of the innermost tubular body (3). Further, as shown in FIGS. 1 and 9, for example, the closing body (18, 34, 35, 39) has a shaft end portion on the innermost tubular body (3) near the first cap (7). It can be provided so as to block the internal space of the. Further, the closing body (18, 34, 35, 39) can be formed of, for example, a synthetic resin or a metal. Examples of the synthetic resin or metal include the types exemplified by the material of the tubular body (3 to 5).

Here, when shortening the casing (2), if a large load is not applied from the outside to the innermost cylinder (3), the closing body (18, 35) is made heavier by setting the material, size, and the like. As a result, the casing (2) can be shortened smoothly and quickly. In this case, the axial length of the closing body (18, 35) is, for example, 60% or more (preferably 70% or more) of the axial length of the innermost tubular body (3), as shown in FIG. ) Can be.
On the other hand, when a large load is applied to the innermost cylinder (3) from the outside when shortening the casing (2), the closing body (34, 39) is lightened by setting the material, size, etc. The weight of the cylinders (1A, 1B) can be reduced. In this case, the axial length of the closing body (34, 39) is 50% or less (preferably 40% or less) of the axial length of the innermost tubular body (3), for example, as shown in FIG. ) Can be.

As the cylinder according to the present embodiment, for example, as shown in FIG. 9, the fluid is a liquid, and the closing body (35, 39) is supplied with the liquid to the variable volume space (S1). An example is a mode in which a functional valve (27) for separating air from the liquid accumulated in the variable volume space (S1) and exhausting the air to the outside is provided. The functional valve (27) can be arranged, for example, on the surface side of the closing body (35, 39) that forms the volume variable space (S1). Further, the functional valve (27) can, for example, take in external air into the variable volume space (S1) when discharging the liquid from the variable volume space (S1). The type of the functional valve (27) is not particularly limited, and examples thereof include a float type and a bellows type.
In the above-described embodiment, for example, the closing body (35, 39) is formed with a communication passage (36) that communicates the volume variable space (S1) and the volume invariant space (S2) via the functional valve (27). In the casing (2), an exhaust passage (37) for communicating the volume invariant space (S2) and the outside air can be formed.

As the cylinder according to the present embodiment, for example, as shown in FIG. 1, the innermost cylinder (3) is provided with a second cap (6) so as to close the shaft end opening of the cylinder. In the casing (2), a volume invariant space (S2) is formed which is surrounded by the closing body (18, 34) and the second cap (6) and communicates with the volume variable space (S1). The fluid is a liquid, and in the second cap (6), air is separated from the liquid accumulated in the volume invariant space (S2) when the liquid is supplied to the volume variable space (S1) to the outside. A form in which a functional valve (27) for exhausting to the air is provided can be mentioned. The functional valve (27) can be arranged, for example, on the surface side of the second cap (6) that forms the volume invariant space (S2). Further, the functional valve (27) can take in external air into the volume invariant space (S2) when the liquid is discharged from the volume variable space (S1), for example. The type of the functional valve (27) is not particularly limited, and examples thereof include a float type and a bellows type.
In the above-described embodiment, for example, the second cap (6) may be formed with an exhaust passage (28) that communicates the volume invariant space (S2) with the outside air via the functional valve (27).

The material, size, shape, etc. of the second cap (6) are not particularly limited. The second cap (6) can be made of, for example, a synthetic resin or a metal. Examples of the synthetic resin or metal include the types exemplified by the material of the tubular body (3 to 5).

As the cylinder according to the present embodiment, for example, as shown in FIG. 9, in the inner and outer cylinders adjacent to the inside and outside of the plurality of cylinders, the outer circumference of the inner cylinder (3 (4)) is used. A space (S3) partitioned by the sealing material (11, 13) is formed between the surface and the inner peripheral surface of the outer cylinder (4 (5)), and the outer cylinder (4 (4)) is formed. 5) On the) side, an opening (16) that opens the space (S3) to the outside is provided, and when the fluid is discharged from the variable volume space (S1), the space is passed through the opening (16). A form in which a fluid flows into (S3) can be mentioned. In this case, for example, when the fluid is supplied to the variable volume space (S1), the fluid in the space (S3) can be discharged to the outside through the opening (16).
The type of the fluid is not particularly limited, but may be, for example, the same type as the fluid supplied to the variable volume space (S1).

The use, installation form, etc. of the cylinders (1A, 1B) are not particularly limited. Applications of this cylinder include, for example, household bathing lifts, bathing assistance lifts for facilities, power of elevating wheelchairs, lifts and equipment for food processing factories, food facilities, food service centers, elevators for gas stations, and elevating for pets. Tables, lifting devices used in stores and processing plants that handle fresh food, lifting lift equipment for orchards and farm work tables, luggage lifting lifts in places where power is difficult to obtain, such as campgrounds and outdoor facilities, and homes. Elevating and lowering of simple workbench, elevating device such as toilet seat, flow table, wash basin, flap elevating device of pay parking lot, vertical drive device of pool floor depth, elevating device used outdoors / underwater, emergency use in case of power failure Power unit, power for explosion-proof specifications (equipment / facility / room where electricity / oil cannot be used), jack for disaster (outdoor / underwater use), jack / elevating device using water pressure during tsunami / flood, house・ Step elimination device in facilities, outdoor / indoor work table elevating and pallet elevating device, automobile jack, elevating car wash table, drive of damper for explosion-proof device (LP / propane gas, petroleum), vehicle stop Examples include lifting devices such as poles and fences, lifting devices such as tables, work tables and counters, ring stopper flaps for parking lots, and lifting devices such as tables, work tables and counters.

As shown in FIG. 1, for example, the cylinders (1A and 1B) may be installed vertically so that the expansion / contraction direction of the casing (2) is along the vertical direction, or the expansion / contraction direction of the casing (2). May be installed sideways so as to be along the horizontal direction, or may be installed so as to be inclined so that the expansion and contraction direction of the casing (2) is inclined with respect to the vertical direction (or the horizontal direction). ..

<Elevating device>
As shown in FIGS. 14 to 16, for example, the elevating device according to the present embodiment is an elevating device (41A, 41B, 46) including the above-mentioned cylinders (1A, 1B), and the cylinders (1A, 1B). ) Moves up and down an object (for example, an article, a person, an animal, etc.).

The reference numerals in parentheses of each configuration described in the above-described embodiment indicate the correspondence with the specific configurations described in the examples described later.

Hereinafter, the present invention will be specifically described with reference to the drawings. In this embodiment, as the "cylinder" according to the present invention, hydraulic cylinders 1A and 1B in which the expansion / contraction direction of the casing 2 is the vertical direction P are exemplified.

<Example 1>
(1) Configuration of hydraulic cylinder The hydraulic cylinder 1A according to the present embodiment includes a retractable casing 2 as shown in FIGS. 1 and 2. The casing 2 includes a plurality of (three in the figure) cylinders 3, 4, and 5 connected in a telescope shape. These plurality of cylinders 3 to 5 have a telescopic structure.

The outermost cylinder 5 (that is, the lowermost cylinder 5) of the plurality of cylinders 3 to 5 is closed with the shaft end opening of the cylinder 5 (that is, the opening at one end of the casing 2). A first cap 7 is provided on the surface. Further, in the innermost cylinder 3 (that is, the uppermost cylinder 3) among the plurality of cylinders 3 to 5, the shaft end opening of the cylinder 3 (that is, the other end opening of the casing 2) is provided. A second cap 6 is provided so as to close the cap.

Each of the above-mentioned cylinders 3 to 5 is formed in a cylindrical shape by a synthetic resin. Further, the first cap 7 is formed of a synthetic resin in the shape of a square plate (see FIG. 3). The first cap 7 functions as a pedestal. Further, the second cap 6 is formed in a disk shape by a synthetic resin. Further, the caps 6 and 7 are attached to the shaft ends of the cylinders 3 and 5 by screwing, bonding, welding, fitting or the like.

In the inner and outer cylinders 3 and 4 adjacent to the inner and outer sides of the plurality of cylinders 3 to 5, the shaft end portion of the inner cylinder 3 is pressed against the inner peripheral surface of the outer cylinder 4. A ring member 12 provided with a sealing material 11 (for example, an O-ring, packing, etc.) is provided. The ring member 12 is made of synthetic resin. Further, the ring member 12 is attached to the tubular body 3 by screwing, bonding, welding, fitting, or the like. Further, a ring member 14 provided with a scraper 13 (sealing material 13) that is in pressure contact with the outer peripheral surface of the inner cylinder 3 is provided at the shaft end portion of the outer cylinder 4. The ring member 14 is made of synthetic resin. Further, the ring member 14 is attached to the tubular body 4 by screwing, bonding, welding, fitting, or the like.
The inner and outer cylinders 4 and 5 adjacent to the inside and outside are also provided with the ring members 12 and 14 in substantially the same manner as described above.

In the extended state B (see FIG. 2) of the casing 2, the ring members 12, 14 of the inner and outer cylinders 3, 4 (4, 5) come into contact with each other, so that the cylinders 3, 4 (4, 5) come into contact with each other. Relative movement is regulated.

The ring member 14 is provided with an opening 16 that opens a space between the inner cylinder 3 and the outer cylinder 5 partitioned by the sealing material 11 and the scraper 13 to the outside. The opening 16 is formed in a passage shape in which one end side faces the space and the other end side faces the outside. Then, when the casing 2 is extended, the air in the space is exhausted to the outside through the opening 16, so that the air in the space is compressed and the internal air pressure is prevented from rising. Further, when the casing 2 is shortened, the outside air is sucked into the space through the opening 16, so that the space does not have a negative pressure.

In this embodiment, the opening 16 is provided in the ring member 14, but the present invention is not limited to this, and for example, the opening 16 may be provided in the vicinity of the joint with the ring member 14 in the cylinders 3 to 5. good.

Inside the innermost cylinder 3, a columnar closing body 18 is provided so as to close the internal space of the cylinder 3. The closing body 18 is provided so as to close the internal space of the shaft end portion on the innermost tubular body 3 near the first cap 7. Further, the closing body 18 is made of metal, and its axial length is set to a value of about 80% of the axial length of the innermost tubular body 3. Therefore, the closing body 18 is relatively heavy and functions as a weight. Further, the closing body 18 is attached to the tubular body 3 by screwing, bonding, welding, fitting, or the like.

In the casing 2, a variable volume space S1 surrounded by the closing body 18 and the first cap 7 is formed, and a volume invariant space S2 surrounded by the closing body 18 and the second cap 6 is formed. There is. Both spaces S1 and S2 communicate with each other through a gap 19 formed between the outer peripheral surface of the closing body 18 and the inner peripheral surface of the innermost tubular body 3.

The first cap 7 is formed with a port 21 (that is, a supply / discharge path 21) for supplying and discharging water to the variable volume space S1. One end side of the port 21 is open to the side surface of the first cap 7, and the other end side is open to the surface forming the volume variable space S1 of the first cap 7. Further, the other end side of a connection pipe 23 such as a hose whose one end side is connected to the tap water faucet 22 is connected to the port 21 (see FIG. 1). A switching valve 24 that can be manually operated is provided in the middle of the connecting pipe 23. The switching valve 24 can be switched between a state in which water is supplied to the port 21, a state in which water is drained from the port 21, and a state in which water supply and drainage to the port 21 are stopped.

The casing 2 is expanded by supplying water to the variable volume space S1 in the shortened state A (see FIG. 1) of the casing 2 through the port 21, and the volume is variable in the expanded state B (see FIG. 2) of the casing 2. The casing 2 is shortened by discharging water from the space S1. The volume variable space S1 is expanded and contracted according to the expansion and contraction operation of the casing 2.

The second cap 6 is provided with a functional valve 27 that separates air from the water accumulated in the volume invariant space S2 when supplying water to the volume variable space S1 and exhausts the air to the outside. That is, when supplying water to the volume variable space S1, the functional valve 27 exhausts the air in the volume invariant space S2 to the outside while restricting the outflow of the water accumulated in the volume invariant space S2 to the outside. Further, the functional valve 27 takes in external air into the volume invariant space S2 when the water is discharged from the volume variable space S1. Further, the functional valve 27 is arranged on the surface side of the second cap 6 that forms the volume invariant space S2. Further, a part of the functional valve 27 protrudes into the volume invariant space S2.

As shown in FIG. 6, the functional valve 27 includes a main body 27a and a valve body 27b provided in the main body 27a so as to be able to move up and down. The main body 27a is attached to the second cap 6 by screwing, bonding, welding, fitting, or the like. Further, in the main body 27a, there is a first connecting path 31 that connects the exhaust passage 28 formed in the second cap 6 and the volume invariant space S2, and the lower space and the volume invariant space S2 of the valve body 27b in the main body 27a. A second connecting path 32, which communicates with the above, is formed.

According to the functional valve 27, when water is supplied into the variable volume space S1 in the shortened state A of the casing 2, the valve body 27b is positioned at the descending end by its own weight (or the urging force of the spring). The air in the volume invariant space S2 is exhausted to the outside through the connecting path 31 and the exhaust path 28 (see FIG. 6A). On the other hand, when the volume invariant space S2 is filled with water through the gap 19, the valve body 27b is raised when the water pressure applied to the valve body 27b exceeds its own weight, and the valve body 27b becomes the first connecting path. Closing the 31 prevents water from leaking to the outside (see FIG. 6 (b)). Further, when water is discharged from the volume variable space S1 in the extended state B of the casing 2, the bubble body 27b is lowered by its own weight because the water pressure becomes the same as the atmospheric pressure, and the exhaust passage 28 and the first contact are connected. Atmosphere (ie, external air) flows into the volume invariant space S2 (ie, casing 2) through the path 31.

(2) Action of the hydraulic cylinder Next, the action of the hydraulic cylinder 1A having the above configuration will be described. As shown in FIG. 1, in the shortened state A of the casing 2, the switching valve 24 is switched to supply tap water into the variable volume space S1. Then, the volume variable space S1 in the shortened state is filled with water and the volume variable space S1 expands, so that the innermost cylinder 3 rises with respect to the other cylinders 4 and 5 (see FIG. 4). ). At this time, the air and water in the volume variable space S1 reach the volume invariant space S2 through the gap 19, and the air in the volume invariant space S2 is exhausted to the outside by the functional valve 27 (see FIG. 6A). .. After that, the variable volume space S1 is further expanded by the supply of water, so that the innermost and intermediate cylinders 3 and 4 are integrally raised with respect to the outermost cylinder 5 (see FIG. 5). As a result, the casing 2 is in the extended state B.

On the other hand, as shown in FIG. 2, in the extended state B of the casing 2, the switching valve 24 is switched to discharge the water in the variable volume space S1. Then, due to the weight of the cylinder 3 and the closing body 18, the innermost and intermediate cylinders 3 and 4 with respect to the outermost cylinder 5 are lowered at any time or as appropriate. After that, when the intermediate cylinder 4 descends to the minimum, the innermost cylinder 3 descends with respect to the intermediate and outermost cylinders 4 and 5. As a result, the casing 2 is in the shortened state A.

(3) Effect of Example According to the hydraulic cylinder 1A of this embodiment, the casing 2 includes a plurality of cylinders 3 to 5 connected in a telescope shape, and is the innermost of the plurality of cylinders 3 to 5. The cylinder 3 is provided with a closing body 18 so as to close the internal space of the cylinder 3, and the outermost cylinder 5 among the plurality of cylinders 3 to 5 is provided with the cylinder 5. The first cap 7 is provided so as to close the shaft end opening of the above. A volume variable space S1 surrounded by the closing body 18 and the first cap 7 is formed in the casing 2, and the casing 2 is extended by supplying water to the volume variable space S1 to extend the volume variable space. The casing 2 is shortened by discharging water from S1. As a result, when the casing 2 is extended, the volume variable space S1 having a relatively small volume in the shortened state is filled with water, so that the innermost cylinder 3 is compared with the other cylinders 4 and 5. Start moving. Therefore, the extension operation of the casing 2 can be accelerated, and the amount of water for the operation can be reduced. Further, when shortening the casing 2, even if a large load is not applied to the innermost cylinder 3 from the outside, the casing 2 can be made heavier by setting the material, size, and the like. Can be shortened smoothly and quickly.

In particular, since the hydraulic cylinder 1A of the present embodiment is operated using tap water, it can be used as a safe and secure actuator in places where electricity and oil cannot be used or where it is not desired to be used. Specifically, since the power source is only tap water, no power supply is required, the electricity bill is zero, and energy is saved. In addition, there is no concern about electric shock or electric leakage, and it is safe. In addition, there is little vibration, the sound is quiet, and there is no sudden drop when going up and down, so it is safe. In addition, there is no concern about oil leakage and grease scattering, CO2 emissions are small, and environmental protection can be achieved. Furthermore, it has a simple structure, is lightweight and compact. Furthermore, it can be used outdoors, underwater, explosion-proof facilities, clean rooms, etc.

Further, in the present embodiment, the closing body 18 is provided so as to close the internal space of the shaft end portion on the innermost tubular body 3 near the first cap 7. As a result, the extension operation of the casing 2 can be further accelerated, and the amount of water for the operation can be further reduced. That is, it is possible to save the amount of water corresponding to the volume inside the innermost cylinder 3.

Further, in this embodiment, the innermost cylinder 3 is provided with a second cap 6, a volume invariant space S2 is formed in the casing 2, and the second cap 6 is a functional valve. 27 is provided. As a result, when the casing 2 is extended, the air is separated from the water accumulated in the volume invariant space S2 by the functional valve 27 and exhausted to the outside, so that the pressure is almost exclusively generated by the water and the casing 2 is extended. The operation is stable. Further, when the casing 2 is extended, water can be filled over the volume variable space S1 and the volume invariant space S2 in the casing 2.

Further, in this embodiment, the functional valve 27 is arranged on the surface side of the second cap 6 that forms the volume invariant space S2. As a result, the functional valve 27 does not protrude to the outer surface of the second cap 6, and the second cap 6 can be effectively used. For example, when the hydraulic cylinder 1A is used as an elevating device, the second cap 6 can be effectively connected to the table constituting the elevating device.

In the above embodiment, a gap 19 is formed between the inner peripheral surface of the tubular body 3 and the outer peripheral surface of the closing body 18 so that both spaces S1 and S2 can communicate with each other, but the present invention is not limited to this. For example, a communication passage 19'(indicated by a virtual line in FIG. 1) may be formed in the closing body 18 so that both spaces S1 and S2 can communicate with each other.

Further, in the above embodiment, the closing body 18 which is a separate body from the cylinder 3, the second cap 6 and the ring member 12 is exemplified, but the present invention is not limited to this, and for example, the cylinder 3, the second cap 6 or The closing body 18 integrally molded with the ring member 12 may be used.

<Modification 1 of Example 1>
Next, the hydraulic cylinder 1A (see FIG. 7) according to the first modification of the first embodiment will be described. In the hydraulic cylinder 1A of the present modification 1, substantially the same constituent parts as those of the hydraulic cylinder 1A of the first embodiment are designated by the same reference numerals, detailed description thereof will be omitted, and the differences between the two will be described.

In the hydraulic cylinder 1A according to the first modification, as shown in FIG. 7, a cylindrical closing body 34 is provided in the innermost cylinder 3 so as to close the internal space of the cylinder 3. .. The closing body 34 is provided so as to close the internal space of the shaft end portion on the innermost tubular body 3 near the first cap 7. Further, the closing body 34 is made of synthetic resin, and its axial length is set to a value of about 30% of the axial length of the innermost tubular body 3. Therefore, the closing body 34 is relatively light. Further, the closing body 34 is attached to the tubular body 3 by screwing, bonding, welding, fitting, or the like.
The hydraulic cylinder 1A of the present modification 1 is premised on the fact that a large load is applied from the outside to the innermost cylinder 3 when the casing 2 is shortened.

According to the hydraulic cylinder 1A of the present modification 1, in addition to exhibiting substantially the same action and effect as the hydraulic cylinder 1A of the first embodiment, a relatively light closing body 34 is adopted, so that the closing body 34 and thus the hydraulic cylinder It is possible to reduce the weight of the cylinder.

In addition, in this modification 1, the closing body 34 provided so as to close the internal space of the shaft end portion on the side close to the first cap 7 in the innermost cylinder 3 is exemplified, but the present invention is not limited to this, and for example. As shown by a virtual line in FIG. 7, the closing body 34 may be provided so as to close the internal space of the innermost tubular body 3 at a portion separated from the shaft end portion on the side closer to the first cap 7.

<Modification 2 of Example 1>
Next, the hydraulic cylinder 1A (see FIG. 8) according to the second modification of the first embodiment will be described. In the hydraulic cylinder 1A of the present modification 2, the same components as those of the hydraulic cylinder 1A of the first embodiment are designated by the same reference numerals, detailed description thereof will be omitted, and the differences between the two will be described.

In the hydraulic cylinder 1A according to the second modification, the functional valve 27 is attached from the upper surface side of the second cap 6 as shown in FIG. According to the hydraulic cylinder 1A of the second modification, the action and effect are substantially the same as those of the hydraulic cylinder 1A of the first embodiment.

<Example 2>
Next, the hydraulic cylinder 1B according to the second embodiment will be described. In the hydraulic cylinder 1B of the second embodiment, substantially the same constituent parts as the hydraulic cylinder 1A of the first embodiment are designated by the same reference numerals, detailed description thereof will be omitted, and the differences between the two will be described.

(1) Configuration of hydraulic cylinder The hydraulic cylinder 1B according to the present embodiment includes a retractable casing 2 as shown in FIG. The casing 2 includes a plurality of (three in the figure) cylinders 3 to 5.

In the innermost cylinder 3 of the plurality of cylinders 3 to 5, a columnar closing body 35 is provided so as to close the internal space of the cylinder 3. The closing body 35 is provided so as to close the internal space of the shaft end portion on the innermost tubular body 3 near the first cap 7. Further, the closing body 35 is made of metal, and its axial length is set to a value of about 80% of the axial length of the innermost tubular body 3. Therefore, the closing body 35 is relatively heavy and functions as a weight. Further, the closing body 35 is attached to the tubular body 3 by screwing, bonding, welding, fitting, or the like.

In the casing 2, a variable volume space S1 surrounded by the closing body 35 and the first cap 7 is formed, and a volume invariant space S2 surrounded by the closing body 35 and the second cap 6 is formed. There is. Both spaces S1 and S2 communicate with each other through a communication passage 36 formed through the closing body 35. Further, the second cap 6 is formed with an exhaust passage 37 that communicates the volume invariant space S2 with the outside.

A sealing material 38 for sealing between the outer peripheral surface of the closing body 35 and the inner peripheral surface of the tubular body 3 is provided. Further, the closing body 35 is provided with a functional valve 27 that separates air from the water accumulated in the variable volume space S1 when supplying water to the variable volume space S1 and exhausts the air to the outside. That is, when the functional valve 27 supplies water to the variable volume space S1, the functional valve 27 exhausts the air in the variable volume space S1 to the outside while restricting the outflow of the water accumulated in the variable volume space S1 to the outside. Further, the functional valve 27 takes in external air into the variable volume space S1 when the water is discharged from the variable volume space S1. Further, the functional valve 27 is arranged on the surface side of the closing body 35 that forms the volume variable space S1. Further, a part of the functional valve 27 protrudes into the variable volume space S1.

The functional valve 27 includes a main body 27a and a valve body 27b provided in the main body 27a so as to be able to move up and down (see FIG. 6). The main body 27a is attached to the closing body 35 by screwing, bonding, welding, fitting, or the like. Further, the main body 27a has a first connecting path 31 that connects the communication passage 36 and the variable volume space S1, and a second connecting path that connects the lower space of the valve body 27b in the main body 27a and the variable volume space S1. 32 and are formed.

According to the functional valve 27, when water is supplied into the variable volume space S1 in the shortened state A of the casing 2, the valve body 27b is positioned at the descending end by its own weight (or the urging force of the spring). The air in the volume variable space S1 is exhausted to the outside through the connecting path 31, the communication passage 36, and the exhaust passage 37. On the other hand, when the volume variable space S1 is filled with water, the valve body 27b is raised when the water pressure applied to the valve body 27b exceeds its own weight, and the valve body 27b closes the first connecting path 31. Prevents water from leaking to the outside. Further, when water is discharged from the volume variable space S1 in the extended state B of the casing 2, the bubble body 27b descends due to its own weight because the water pressure becomes the same as the atmospheric pressure, and the exhaust passage 37 and the volume invariant space. Atmospheric pressure (that is, external air) flows into the variable volume space S1 (that is, casing 2) through S2, the communication passage 36, and the first connecting path 31.

In the inner and outer cylinders 3, 4 (4, 5) adjacent to the inside and outside of the plurality of cylinders, the outer peripheral surface of the inner cylinder 3 (4) and the inside of the outer cylinder 4 (5). A cylindrical space S3 partitioned by the sealing materials 11 and 13 is formed between the peripheral surface and the peripheral surface. Further, on the outer tubular body 4 (5) side (specifically, the ring member 14), a passage-shaped opening 16 for opening the space S3 to the outside is provided. A pipe 53 connected to a tap water faucet (not shown) is connected to the opening 16. The pipe 53 is provided with a switching valve 54 such as a 5-way valve. The switching valve 54 makes it possible to switch between a state in which water is supplied to the opening 16, a state in which water is drained from the opening 16, and a state in which water supply and drainage to the opening 16 are stopped.
In this embodiment, the opening 16 is provided in the ring member 14, but the present invention is not limited to this, and for example, the opening 16 is provided in the vicinity of the joint with the ring member 14 in the tubular body 4 (5). May be good.

(2) Action of the hydraulic cylinder Next, the action of the hydraulic cylinder 1B having the above configuration will be described. As shown in FIG. 9, in the shortened state A of the casing 2, the switching valve 24 is switched to supply tap water into the variable volume space S1. Then, the volume variable space S1 in the shortened state is filled with water and the volume variable space S1 expands, so that the innermost cylinder 3 rises with respect to the other cylinders 4 and 5 (see FIG. 10). ). At this time, the air in the variable volume space S1 is exhausted to the outside by the functional valve 27. After that, the variable volume space S1 is further expanded by the supply of water, so that the innermost and intermediate cylinders 3 and 4 are integrally raised with respect to the outermost cylinder 5 (see FIG. 11). As a result, the casing 2 is in the extended state B.
In the extension operation of the casing 2, the water in the space S3 is discharged to the outside through the opening 16 by the switching valve 54, so that the water in the space S3 is not compressed and the water pressure is prevented from rising. Will be done.

On the other hand, in the extended state B of the casing 2, the switching valve 24 is switched to discharge the water in the variable volume space S1. Then, due to the weight of the cylinder 3 and the closing body 35, the innermost and intermediate cylinders 3 and 4 with respect to the outermost cylinder 5 are lowered at any time or as appropriate. After that, when the intermediate cylinder 4 descends to the minimum, the innermost cylinder 3 descends with respect to the intermediate and outermost cylinders 4 and 5. As a result, the casing 2 is in the shortened state A.
Here, in the shortening operation of the casing 2, water flows into the space S3 through the opening 16 by the switching valve 54. As a result, the casing 2 is shortened by its own weight while the cylinders 3 and 4 are pushed downward by the inflow of water into the space S3.

(3) Effect of Example According to the hydraulic cylinder 1B of the second embodiment, in addition to exhibiting substantially the same action and effect as the hydraulic cylinder 1A of the first embodiment, the closing body 35 is provided with a functional valve 27. ing. As a result, when the casing 2 is extended, the air is separated from the water accumulated in the variable volume space S1 by the functional valve 27 and exhausted to the outside, so that the pressure is almost exclusively generated by the water, and the casing 2 is extended. The operation is stable. Further, the functional valve 27 can be easily mounted in the innermost cylinder 3. Further, as compared with the hydraulic cylinder 1A (see FIG. 1) in which the functional valve 27 is provided on the second cap 6, the thickness of the second cap 6 can be made more compact, and the height of the casing 2 in the shortened state can be made lower.

Further, in this embodiment, the functional valve 27 is arranged on the surface side of the closing body 35 that forms the volume variable space S1. This further enhances the mountability of the functional valve 27.

Further, in this embodiment, a space S3 partitioned by the sealing materials 11 and 13 is formed between the outer peripheral surface of the inner cylinder 3 (4) and the inner peripheral surface of the outer cylinder 4 (5). An opening 16 for opening the space S3 to the outside is provided on the outer tubular body 4 (5) side, and when water is discharged from the volume variable space S1, the opening 16 is provided. Water is made to flow into the space S3. As a result, the casing 2 can be shortened smoothly and quickly by its own weight regardless of the load applied to the casing 2.

In the above embodiment, the embodiment in which the functional valve 27 is arranged on the surface side forming the volume variable space S1 of the closing body 35 is exemplified, but the present invention is not limited to this, and for example, the volume variable space S1 of the closing body 35 is provided. The functional valve 27 may be arranged at a portion separated upward from the surface side to be formed.

Further, in the above embodiment, the closing body 35, which is a separate body from the cylinder 3, the second cap 6, and the ring member 12, is exemplified, but the present invention is not limited to this, and for example, the cylinder 3, the second cap 6, or The closing body 35 integrally formed with the ring member 12 may be used.

<Modification 1 of Example 2>
Next, the hydraulic cylinder 1B (see FIG. 12) according to the first modification of the second embodiment will be described. In the hydraulic cylinder 1B of the present modification 1, substantially the same constituent parts as those of the hydraulic cylinder 1B of the second embodiment are designated by the same reference numerals, detailed description thereof will be omitted, and the differences between the two will be described.

In the hydraulic cylinder 1B according to the first modification, as shown in FIG. 12, a columnar closing body 39 is provided in the innermost cylinder 3 so as to close the internal space of the cylinder 3. .. The closing body 39 is provided so as to close the internal space of the shaft end portion on the innermost tubular body 3 near the first cap 7. Further, the closing body 39 is made of synthetic resin, and its axial length is set to a value of about 30% of the axial length of the innermost tubular body 3. Therefore, the closing body 39 is relatively light. Further, the closing body 39 is attached to the tubular body 3 by screwing, bonding, welding, fitting, or the like.
The hydraulic cylinder 1B of the present modification 1 is premised on the fact that a large load is applied from the outside to the innermost cylinder 3 when the casing 2 is shortened.

According to the hydraulic cylinder 1B of the present modification 1, in addition to exhibiting substantially the same action and effect as the hydraulic cylinder 1B of the second embodiment, a relatively light closing body 39 is adopted, so that the closing body 39 and thus the hydraulic cylinder It is possible to reduce the weight of the cylinder.

In addition, in this modification 1, the closing body 39 provided so as to close the internal space of the shaft end portion on the side close to the first cap 7 in the innermost cylinder 3 is exemplified, but the present invention is not limited to this, and for example. As shown by a virtual line in FIG. 12, the closing body 39 may be provided so as to close the internal space of the innermost tubular body 3 at a portion separated from the shaft end portion on the side close to the first cap 7.

Further, in the present modification 1, the closing body 39 which is a separate body from the cylinder body 3, the second cap 6 or the ring member 12 is exemplified, but the present invention is not limited to this, and for example, the cylinder body 3, the second cap 6 is used. Alternatively, the closing body 39 integrally formed with the ring member 12 may be used.

<Modification 2 of Example 2>
Next, the hydraulic cylinder 1B (see FIG. 13) according to the first modification of the second embodiment will be described. In the hydraulic cylinder 1B of the present modification 1, substantially the same constituent parts as those of the hydraulic cylinder 1B of the second embodiment are designated by the same reference numerals, detailed description thereof will be omitted, and the differences between the two will be described.

In the hydraulic cylinder 1B according to the second modification, as shown in FIG. 13, a closing body 35 is provided in the innermost cylinder 3 so as to close the internal space of the cylinder 3. The tubular body 3 and the closing body 35 are made of the same kind of material (for example, synthetic resin or metal) and are integrally molded. According to the hydraulic cylinder 1B of the second modification, the action and effect are substantially the same as those of the hydraulic cylinder 1B of the second embodiment.

<Use of hydraulic cylinder>
The article elevating device 41A using the hydraulic cylinders 1A and 1B of Examples 1 and 2 described above will be described. As shown in FIG. 14, the article elevating device 41A is launched on a trolley 42A that can travel, a table 44A that is movably supported by the trolley 42A via a support portion 43A, and a trolley 42A. It includes hydraulic cylinders 1A and 1B whose upper ends are connected to the table 44A. According to the article lifting device 41A, the article on the table 44A is lifted and lowered by the expansion and contraction of the hydraulic cylinders 1A and 1B.

Next, another article elevating device 41B using the hydraulic cylinders 1A and 1B of Examples 1 and 2 described above will be described. As shown in FIG. 15, the article elevating device 41B is launched on a trolley 42B that can travel, a table 44B that is movably supported by the trolley 42B via a support portion 43B, and a trolley 42B. It includes hydraulic cylinders 1A and 1B whose upper ends are connected to the table 44B. According to the article lifting device 41B, the article on the table 44B is lifted and lowered by the expansion and contraction of the hydraulic cylinders 1A and 1B.

Next, the bathing assist device 46 using the hydraulic cylinders 1A and 1B of Examples 1 and 2 described above will be described. As shown in FIG. 16, the bathing assist device 46 is supported via a support portion 47 with respect to the hydraulic cylinders 1A and 1B raised on the floor surface outside the bathtub and the upper ends of the hydraulic cylinders 1A and 1B. It is equipped with a seat 48. According to the bathing auxiliary storage 46, the user sitting on the seat 48 is moved up and down with respect to the bathtub by expanding and contracting the hydraulic cylinders 1A and 1B.

It should be noted that the present invention is not limited to the above-mentioned examples, and various modifications can be made within the scope of the present invention according to the purpose and use. That is, in Examples 1 and 2, the casing 2 having three cylinders 3 to 5 is exemplified, but the casing 2 is not limited to this, and for example, the casing 2 having four or more cylinders may be used. It may be a casing 2 provided with a tubular body of the above.

Further, in the first and second embodiments, tap water is supplied to the variable volume space S1 of the casing 2, but the present invention is not limited to this, and for example, the pump water is supplied to the variable volume space S1 of the casing 2. The water in the reservoir may be supplied by pumping. Further, the cylinder may be operated by a liquid other than water, or may be operated by a gas such as air.

Further, in the first and second embodiments, the port 21 is set to the first cap 7, but the present invention is not limited to this, and for example, the port 21 is set to the shaft end of the outermost cylinder 5. You may do it. Further, in the above-mentioned Examples 1 and 2, one port 21 for both water supply and discharge is set, but the present invention is not limited to this, and for example, a water supply port and a water discharge port are set. You may set each of the ports of.

Further, in the above embodiment, the passage-shaped opening 16 (see FIG. 1) formed in the ring member 14 is exemplified, but the present invention is not limited to this, and for example, as shown in FIGS. 17 and 18, the tubular body is used. A first groove 51 is formed at the tip of 5 (4), and a second groove 52 for communicating the first groove 51 and the outside air at the joint portion of the ring member 14 of the tubular body 5 (4). The opening 16 may be formed by forming the opening 16.
Further, for example, as shown in FIG. 19A, a first groove 51 is formed at the tip end portion of the tubular body 5 (4), and a first groove 51 is formed at the joint portion of the ring member 14 with the tubular body 5 (4). The opening may be formed by forming a hole 53 for communicating the groove 51 of 1 with the outside air.
Further, for example, as shown in FIG. 19B, a first groove 51 is formed at the tip end portion of the tubular body 5 (4), and a first groove 51 is formed at the joint portion of the ring member 14 with the tubular body 5 (4). The opening 16 may be formed by forming a groove 54 for communicating the groove 51 of 1 with the outside air.
Even in the above-described form, the space between the inner cylinder 3 (4) and the outer cylinder 4 (5) partitioned by the sealing material 11 and the scraper 13 is released to the outside air by the opening 16. ..

Further, in the first and second embodiments, the characteristic configurations of the cylinders 1A and 1B can be freely combined. For example, the fluid supply structure to the opening 16 in the second embodiment may be applied to the first embodiment.

The present invention is widely used as a cylinder that expands and contracts a casing by utilizing water pressure, hydraulic pressure, pneumatic pressure, or the like. In particular, it is suitably used as a cylinder that powers an elevating device that raises and lowers an object such as an article or a person.

1A, 1B; hydraulic cylinder, 2; casing, 3, 4, 5; cylinder, 6; second cap, 7; first cap, 18, 34, 35, 39; closing body, 27; functional valve, S1; Variable volume space, S2; Invariant volume space.

Claims (10)

A cylinder with a telescopic casing
The casing comprises a plurality of cylinders connected in a telescope shape.
The innermost cylinder of the plurality of cylinders is provided with a closing body so as to substantially close the internal space of the cylinder.
The outermost cylinder of the plurality of cylinders is provided with a first cap so as to close the shaft end opening of the cylinder.
A variable volume space surrounded by the closing body and the first cap is formed in the casing.
A cylinder characterized in that the casing is extended by supplying a fluid to the variable volume space, and the casing is shortened by discharging the fluid from the variable volume space. A cylinder with a telescopic casing
The casing comprises a plurality of cylinders connected in a telescope shape.
The innermost cylinder of the plurality of cylinders is provided with a closing body so as to close the internal space of the cylinder.
The outermost cylinder of the plurality of cylinders is provided with a first cap so as to close the shaft end opening of the cylinder.
A variable volume space surrounded by the closing body and the first cap is formed in the casing.
A cylinder characterized in that the casing is extended by supplying a fluid to the variable volume space, and the casing is shortened by discharging the fluid from the variable volume space. The cylinder according to claim 1, wherein the closing body is provided so as to substantially close the internal space of the shaft end portion on the innermost cylinder near the first cap. The cylinder according to claim 2 , wherein the closing body is provided so as to close the internal space of the shaft end portion on the innermost cylinder near the first cap. The fluid is a liquid and
2 . The cylinder described. The cylinder according to claim 5 , wherein the functional valve is arranged on the surface side of the closing body that forms the volume variable space. A second cap is provided on the innermost cylinder so as to close the shaft end opening of the cylinder.
In the casing, a volume invariant space is formed which is surrounded by the closing body and the second cap and communicates with the volume variable space.
The fluid is a liquid and
The second cap is provided with a functional valve that separates air from the liquid accumulated in the volume invariant space and exhausts it to the outside when the liquid is supplied to the volume variable space. Cylinder described in. The cylinder according to claim 7 , wherein the functional valve is arranged on the surface side of the second cap that forms the volume invariant space. In the inner and outer cylinders adjacent to each other inside and outside of the plurality of cylinders, the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder are partitioned by a sealing material. Space is formed,
An opening that opens the space to the outside is provided on the outer cylinder side.
The cylinder according to any one of claims 1 to 8 , wherein when the fluid is discharged from the variable volume space, the fluid flows into the space through the opening. An elevating device comprising the cylinder according to any one of claims 1 to 9 .

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