The invention relates in general to mattresses for medical or hospital beds, and more particularly, to control of pneumatic pressures imposed on selected portions of a mattress.
In medical and other similar settings, beds often comprise mattresses having pneumatically inflated cells for supporting the weight of a patient on the bed. One such mattress is a reactive mattress, which may be comprised of foam and pneumatic components, which are adapted to provide passive and active therapy. Such a mattress may be comprised of pneumatic cells filled with foam, which provides passive therapy in the form of pressure redistribution in a non-powered mode by allowing air to move from cell to cell in reaction to the patient's body movement and weigh to minimize both intensity and duration of pressure exposure to vulnerable skin sites that are not adapted to sustained and/or excessive loading. The mattress can be a hybrid mattress, which can be connected to an air source (e.g., a compressor, pump or other suitable air source) to provide active therapy, such as alternating pressure therapy, to enhance and optimize pressure redistribution and pressure injury prevention. During alternating pressure therapy, the air source inflates and deflates the pneumatic cells to maintain a desired pressure regardless of the patient's weight and position. As a further note, the mattress may be fully active, relying on the air source for maintaining pressure in the mattress, and having no foam in the cells. Such mattresses are often comprised of individual cells, which may extend laterally of the mattress (i.e., in a side-to-side direction) and/or longitudinally of the mattress (i.e., in a lengthwise direction), and zones, such as, for example, back, seat and leg zones, which may correspond to portions of the patient's body.
These mattresses are often used on beds having an adjustable or articulating bed deck supporting a mattress, which includes a backrest section that is movable by virtue of corresponding movement of the bed deck. The backrest section may, for example, be movable from a horizontal position to an inclined position, wherein the backrest section is at some angle inclination relative to the horizontal position. This is commonly referred to as a Fowler position. As the backrest section is moved from the horizontal position to the inclined position, the weight of the patient on the bed shifts, for example, with greater weight borne by the buttocks of the patient and less weight borne by the patient's back. This change requires commensurate control of the pressure in the pneumatic cells in a seat section of the mattress, for example, an increased or sustained pressure in the pneumatic cells of the seat section, which may be lost to the pneumatic cells of the backrest section of the mattress as the angle of inclination of the backrest section increases. This increased or sustained pressure in the pneumatic cells of the seat section is commonly referred to as a Fowler boost. Failure to control this pressure could result in detrimental effects to the patient. One well known hazard is decubitus ulcers, which may develop responsive to excessive weight and therefore, pressure imposed on different body parts, such as, boney prominences of the patient's buttocks. This often occurs when the patient “bottoms out” against the bed deck due to insufficient pressure in the pneumatic cells of the seat section.
In the aforementioned example, it would be desirable to control pressure in pneumatic cells of the seat section of the mattress. Pressure can easily be accommodated by sensing pressures within the various pneumatic cells, sensing the backrest position and using an electronic control system to control or regulate pressures within the various pneumatic cells. However, although this is a frequently employed conventional response to pressure control, it may be objectionable for various reasons. For example, it may require a relatively expensive apparatus distributed about the bed, thereby increasing both cost and complication of the bed, and presenting diverse aspects of the bed that may present problems. Additionally, an electronic control system will not operate in the absence of electrical power, and as a consequence, may be unreliable.
There exists a need for an uncomplicated, low-cost reliable control arrangement to reduce pressure migration from the pneumatic cells of the seat section to the pneumatic cells of the backrest section of an inflatable mattress, effectively providing a Fowler boost.
The present invention addresses the aforementioned need by providing a mechanical valve assembly configured for use with a bed comprising a pneumatic mattress having a backrest section that is configured to be adjustable at some angle in relation to a seat section. The backrest and seat sections are comprised of pneumatic cells that are in fluid communication with one another. The valve is situated between the pneumatic cells of the backrest and the pneumatic cells of the seat sections to control fluid flow therebetween by use of gravity. As the backrest section is raised, a weight of the valve urges the valve to close, and thereby prevents fluid flow from the pneumatic cells of the seat section to the pneumatic cells of the back section, thus increasing or sustaining pressure in the seat section, effectively achieving Fowler boost.
When the backrest section of the mattress is in a horizontal position, there is no need to control the fluid flow between the pneumatic cells of the backrest section and the seat section of the mattress. Consequently, in this position, gravity does not act on the weight of the valve to cause the valve to close. As a consequence, pressure may be equalized throughout the pneumatic cells of the backrest and seat sections of the mattress.
The valve may be coupled to pneumatic cells of the backrest section within a conduit in fluid communication with pneumatic cells of the backrest section and pneumatic cells of the seat section of the mattress. Locating the valve in relation to the backrest section of the mattress, or a corresponding portion of the bed deck, causes the weight to respond automatically to inclination of the backrest section of the mattress to control the valve accordingly. External connections for signaling and power are eliminated.
Various features and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein:
The drawings are diagrammatic rather than literal depictions of their content, do not purport to show all structure or every component that would be present in a real-world model, and are not necessarily drawn to scale.
Referring now to the drawings, there is illustrated in
The mattress 104 may be a pneumatically inflatable reactive mattress comprised of pneumatic cells filled with foam, which allows air to move from cell to cell in reaction to the patient's body movement and weight. The mattress can be connected to an air source (e.g., a compressor, pump or other suitable air source) to provide to enhance and optimize pressure redistribution and reduce the risk of pressure injury to the patient. It should be noted that the mattress may be a fully active mattress with no foam component.
An air supply manifold or conduit 116, shown in
A mechanical valve assembly 118, shown in
The mechanical valve assembly 118 mechanically controls pneumatic pressure in the mattress 104 automatically in response to gravitational affects as the backrest section 120 pivots from a lowered position shown in
The pneumatically inflatable mattress 104 may have a plurality of first and second pneumatic cells 110 and 112, as shown in
Unless otherwise indicated, the terms “first”, “second”, etc., are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to, for example, a “second” item does not either require or preclude the existence of, for example, a “first” or lower-numbered item, and/or, for example, a “third” or higher-numbered item.
The air supply conduit 116 may be understood to encompass a complete system (e.g., a manifold system), which may include several sections of the air supply conduit 116 (e.g., tubing) connecting intervening components, such as the first pneumatic cells 110, the mechanical valve assembly 118, and the second pneumatic cells 112. A portion of a supply conduit 116 is illustrated in
It should be appreciated that, instead of forming a part of a manifold system, the conduit 116 may be integral with the pneumatic cells (e.g., pneumatic cells 110 and 112). In this case, the mechanical valve assembly 118 may be positioned in the conduit 116 between the cells (e.g., between a first pneumatic cell 110 and an adjacent second pneumatic cell 112).
As indicated above, the mechanical valve assembly 118 may be supported in relation to the backrest section 120 and configured to automatically control air flow (i.e., by gravitational influence) between the seat zone 108 and the backrest zone 106 when the backrest section 120 moves from a lowered position to a raised position, shown in
It should be appreciated that the mechanical valve assembly 118 may be supported in relation to the bed deck 103 or the mattress 104. This may be done in any suitable fashion. With the mechanical valve assembly 118 supported in relation to adjacent pneumatic cells 110 and 112 in the backrest and seat sections 120 and 121, air flow between the adjacent cells 110 and 112 may be controlled.
As illustrated in
A resilient valve biasing member 130 (e.g., a coil spring) may urge the valve 128 into a normally closed position. The resilient valve biasing member 130 may be in tension when positioned downstream or below the valve seat 126 (to the left of the valve seat 126 when viewing
It be understood that it may be desirable in some instances for the resilient valve biasing member 130 to urge the valve 128 into an open position. For example, the resilient valve biasing member 130 may alternatively be in compression when positioned downstream or below the valve seat 126 (to the left of the valve seat 126 when viewing
A pusher (e.g., mass 132) may be configured to urge the valve 128 to cause the valve 128 to close when the valve 128 is open responsive to gravity when the backrest section 120 moves to a raised position. Notably, gravity acts on the mass 132 to close the valve 128 when the mechanical valve assembly 118 is in the inclined position, shown in
It should be appreciated that the mass 132 may be fabricated from any suitable material, such as, for example, steel or brass, or some other suitable material, and may be weighted as desired. It should also be appreciated that movement of the mass 132 may also be influenced by the shape and/or configuration of the air supply conduit 116 to supplement the gravitational influence. For example, as shown in
It should be understood that actuation of the valve 128 may be performed by solid components acting under the influence of gravity and may be independent of external power sources, such as electricity. No hydraulic or pneumatic power needs to be applied to the mass 132. It is this combination of characteristics that causes the mechanical valve assembly 118 to be automatically acting and entirely mechanical.
It should also be noted at this point that orientational terms refer to the subject drawing as viewed by an observer. The drawing figures depict their subject matter in orientations of normal use, which could obviously change with changes in posture and position of the bed 110 and its components. Therefore, orientational terms must be understood to provide semantic basis for purposes of description, and do not limit the invention or its component parts in any particular way.
To attain operation described above, the mass 132 may be slidable within the housing 124. The housing 124 may be configured to constrain the mass 132 to slide against the valve 128 when the backrest section 120 is in the inclined position, thereby closing the valve 128, as shown in
The housing 124 and the mass 132 may be configured to constrain the mass 132 to slide linearly or otherwise within the housing 124. For example, actual dimensions and configuration of the housing 124 may form a pathway fitting closely yet slidably (or rotationally) to the mass 132, as shown in
The mechanical valve assembly 118 may further comprise a resilient seal between the valve 128 and the valve seat 126. In the example shown in
In the examples shown in
Bear in mind that the drawing figures are diagrammatic, with no inference or reference to retention structure for coupling the ends of the biasing member 130 to the valve seat 126 and the spring seat 136. It should be understood that the biasing member 130 is preferably in tension (i.e., biased to contract). That is to say, the biasing member 130 is preferably biased to urge the spring seat 136 away from the valve seat 126 and close the valve 128, and the valve 128 is preferably controlled to open by the weight, position and movement of the patient as desired to urge the valve 128 to the opened position. As stated above, it should be understood that, in accordance with this preferred embodiment, the biasing member 130 may be in compression, if positioned, for example, above the valve seat 126.
Returning now to
Broadly presented, the invention controls pressure in air cells as a section of a mattress is raised, without electronic means, but by mechanical means (e.g., a pressure reducing valve (PRV) or control valve between cells in backrest and seat sections of the mattress).
That is to say, the invention provides means for controlling pressure automatically in cells of a pneumatic mattress mechanically, without electrical power, by virtue of a valve positioned in relation to a backrest section of a mattress, or corresponding portion of a bed deck, in a manifold or conduit between two cells. The valve may be in the form of a pressure reducing valve (PRV) or a check valve that has a weight element, which bears onto a sealing element of the valve. As the backrest angle is changed, force keeping the seal closed is overcome by influence of a weighted element via gravitational influence.
In operation, with the backrest section flat, there is a little extra force, and the pressure difference between cell groups is small. As the backrest section is raised, the force to open the valve increases and the pressure in the cell group controlled by the valve (i.e., in the seat section) increases or is sustained.
It should be understood that the invention has been explained and illustrated as an exemplary embodiment. However, it must be understood that the invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.
This application claims priority to U.S. Application No. 63/168,289, filed on Mar. 31, 2021, the disclosure of which is incorporated herein by reference in its entirety.
Number | Name | Date | Kind |
---|---|---|---|
5894966 | Bobey | Apr 1999 | A |
20120317720 | Chiang | Dec 2012 | A1 |
Number | Date | Country |
---|---|---|
WO-2022208163 | Oct 2022 | WO |
Number | Date | Country | |
---|---|---|---|
63168289 | Mar 2021 | US |