This application is generally directed to hydraulic cylinders, such as but not limited to cylinders used for raising and lowering beds.
A number of different types of beds, for example hospital beds, are designed to raise and lower. For example, hospital beds may be designed to raise and lower in a straight configuration and/or one or more parts of the bed may incline and decline. One particular example is the bed of an MRI (magnetic resonance imaging) machine. Such beds need to move in and out of the MRI circular magnet and also need to raise and lower. Typically, a hydraulic cylinder is incorporated into the MRI bed to allow for the raising and lowering. Although such cylinders work well, they can sometimes have size constraints, and they can also have structural weak points from side loads applied to the cylinders.
Therefore, it would be desirable to have an improved hydraulic cylinder for use in beds, such as MRI beds and other hospital beds. It would also be desirable if the improved hydraulic cylinders could be used or adapted or use with other devices and systems. At least some of these objectives will be addressed by the embodiments described in this application.
In one aspect of the present disclosure, a hydraulic cylinder may include a cylindrical body; a first piston rod coupled with a first end of the body, and a second piston rod coupled with a second end of the body. The first piston rod has a cavity with an inner diameter; and the second piston rod has an outer diameter that is smaller than the inner diameter of the cavity. The hydraulic cylinder is adjustable from a closed position, in which at least a majority of a length of the first piston rod is housed inside the body and at least a majority of a length of the second piston rod is housed inside the cavity of the first piston rod, to an extended position, in which the first piston rod extends through the first end of the body and the second piston rod extends through the second end of the body.
In some embodiments, the hydraulic cylinder may include a first head on the first end of the body and a second head on the second end of the body. Some embodiments may also include a first injection port on the first head, for injecting hydraulic fluid into the hydraulic cylinder, and a second injection port on the second head, for injecting hydraulic fluid into the hydraulic cylinder. In some embodiments, the body, the first head and the second head are three separate parts connected together. In alternative embodiments, the body, the first head and the second head are a one-piece, monolithic structure. In alternative embodiments, at least one injection port is located in the body for injecting hydraulic fluid and for allowing the hydraulic fluid to escape the cylinder.
In some embodiments, a first stop member may be coupled with one end of the first piston rod to prevent it from sliding out of the first end of the body in the extended position, and a second stop member may be coupled with one end of the second piston rod to prevent it from sliding out of the second end of the body in the extended position.
In another aspect of the disclosure, a method of manufacturing a hydraulic cylinder may involve attaching a first piston rod with a first end of a cylindrical body so that it is free to slide back and forth through the first end of the body and attaching a second piston rod with a second end of the body so that it is free to slide in and out of the second end of the body. Again, the first piston rod has a cavity with an inner diameter, the second piston rod has an outer diameter that is smaller than the inner diameter of the cavity, and the first and second piston rods translate in and out of the body of the cylinder between closed and extended positions. In the closed position, the second piston nests at least partially within the cavity of the first piston, and both pistons are located at least in part within the body of the cylinder.
In some embodiments, the method may further involve attaching a first head to the first end of the body and attaching a second head to the second end of the body. In some embodiments, the first head and the second head each include an injection port. The method may also include attaching a first stop member with one end of the first piston rod, where the first stop member is configured to abut the first head to prevent the first piston rod from sliding out of the first end of the body in the extended position, and attaching a second stop member with one end of the second piston rod, where the second stop member is configured to abut the second head to prevent the second piston from sliding out of the second end of the body in the extended position.
In yet another aspect of this disclosure, a hydraulic actuator may include: an elongate piston receiver having a first end, an opposite second end, and a longitudinal axis that extends between the first and second ends; a first piston moveable relative to the piston receiver along the longitudinal axis between an extended position, in which a majority of a length of the first piston extends outwardly beyond the first end of the piston receiver, and a retracted position, in which a majority of the length of the first piston element is positioned within the piston receiver; and a second piston moveable relative to the piston receiver along the longitudinal axis between an extended position, in which a majority of a length of the second piston element extends outwardly beyond the second end of the piston receiver, and a retracted position, in which a majority of the length of the second piston element is positioned within the piston receiver. The first piston fits inside the second piston when the first and second pistons are in the retracted positions.
In some embodiments, the piston receiver is a cylinder. In some embodiments, the first piston nests within the second piston when the first and second pistons are in the retracted positions. The hydraulic actuator may be a single acting actuator, according to some embodiments. In some embodiments, the piston receiver defines a port for allowing pressurized hydraulic fluid to be provided within the piston receiver for driving the first and second pistons from the retracted positions to the extended positions. In some embodiments, the first and second pistons concurrently move from the retracted positions to the extend positions.
Optionally, at least a majority of the lengths of the first and second pistons may overlap when the first and second pistons are in the retracted positions. In some embodiments, at least a majority of the length of the first piston is positioned within the second piston when the first and second pistons are in the retracted positons. In some embodiments, the first piston is a solid piston rod and the second piston is a hollow piston rod.
These and other aspects and embodiments of the present application are described in further detail below, in relation to the attached drawing figures.
The following description focuses on various embodiments of a hydraulic cylinder device, which may also be referred to as a “hydraulic cylinder,” “hydraulic actuator” or any other similar term. The cylinder may be used, for example, in a bed, such as a hospital or MRI bed, for lowering and raising the bed. This is but one example of a use for the described hydraulic cylinder embodiments, however, and the description of this example should not be interpreted as limiting the scope of the invention. In various embodiments, the hydraulic cylinder described herein may be used for any suitable purpose and with any suitable device or system.
Referring to
To improve the design of certain beds, such as an MRI bed, it may be desirable to have a hydraulic cylinder with a shorter length in the closed configuration (
Referring now to
To extend cylinder 20, injection fluid, such as oil, water or any other suitable injection medium, may be passed into body 22 via first injection port 36 and/or second injection port 38. As fluid is injected, first piston rod 28 extends through the first end of body 22 and first head 24, and second piston rod 30 extends through the second end of body 22 and second head 26. Eventually the fully extended position is reached, as illustrated in
Cylinder 20 may have virtually any combination of lengths and diameters, depending on the use of cylinder 20. For example, in embodiments for use in an MRI bed, cylinder 20 may have a total extended length of between about 20 cm and about 35 cm, and more ideally between about 25 cm and about 30 cm, and in one embodiment between about 26 cm and about 27 cm. The same cylinder 20 may have a closed/collapsed length of between about 7 cm and about 20 cm, and more ideally between about 10 cm and about 15 cm, and in one embodiment between about 12 cm and about 13 cm.
Referring now to
Hydraulic fluid may be introduced into hydraulic actuator 40 via first port 44, as illustrated in
Although the above description is believed to be complete and accurate, the description is directed toward various exemplary embodiments, and these examples should not be interpreted as limiting the scope of the invention as it is defined by the claims. For example, various alternative embodiments may include fewer components or a greater number of components than the embodiments described above. The methods described herein may also include fewer steps or a greater number of steps and/or the method steps may be performed in a different order. Therefore, the embodiments described herein should not be interpreted as limiting the scope of the invention.
Number | Date | Country | Kind |
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201611041569 | Dec 2016 | IN | national |
This application is a continuation of U.S. patent application Ser. No. 15/830,690, filed 4 Dec. 2017, which claims benefit of Serial No. 201611041569, filed 5 Dec. 2016 in India and which applications are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications.
Number | Date | Country | |
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Parent | 15830690 | Dec 2017 | US |
Child | 16893837 | US |