CN109303439B

CN109303439B - Dynamic foam mattress suitable for use with hospital beds of variable length

Info

Publication number: CN109303439B
Application number: CN201810847857.5A
Authority: CN
Inventors: 凯瑟琳·瓦格纳; 达雷尔·L·伯格曼; 特拉维斯·佩洛; 道格拉斯·E·伯格曼; 凯尔西·G·艾肯斯
Original assignee: Hill Rom Services Inc
Current assignee: Hill Rom Services Inc
Priority date: 2017-07-27
Filing date: 2018-07-27
Publication date: 2021-08-13
Anticipated expiration: 2038-07-27
Also published as: JP2021106929A; JP6869925B2; CN113520748B; CN109303439A; CN113520748A; JP7374146B2; JP2019051296A

Abstract

A non-powered mattress includes a cover enclosing a frame structure and a bladder assembly, the cover adapted to engage a hinged frame to control movement of the bladder assembly and portions of the foam frame in response to movement of the hinged frame.

Description

Dynamic foam mattress suitable for use with hospital beds of variable length

Require priority

According to U.S. patent law 35u.s.c. § 119(e), the present application claims priority to U.S. provisional application No.62/537,943 filed 2017, 7, 27, which is expressly incorporated herein by reference.

Technical Field

The present disclosure relates to mattresses (cushions) for use in a clinical environment. More particularly, the present disclosure relates to a non-powered mattress that uses self-adjusting techniques to control the interface pressure applied at the mattress surface when a patient is positioned thereon.

Background

As hospital bed frames and other patient support devices are advanced and include advanced hinges to allow better customized adjustment and positioning of the patient, the support surface/mattress support on the frame is placed in increasingly complex positions. Relative movement of the components of the mattress relative to the frame may result in improper positioning of the mattress components relative to the patient. In some cases, the internal components shift within the cover of the mattress, causing the mattress to degrade.

Disclosure of Invention

The present disclosure includes one or more of the features recited in the appended claims and/or the following features, which may, alone or in any combination, constitute patentable subject matter.

According to a first aspect of the present disclosure, a patient support device includes a foam frame, a bladder assembly, and a mask body. The foam frame defines a space. The liner assembly is positioned in the space. The bladder assembly includes a plurality of foam-filled bladders, each interconnected by a manifold and having a pressure relief valve (safety valve, pressure regulating valve) to release air from the bladder assembly if the pressure in the bladder assembly exceeds a predetermined limit. The cover encloses the frame structure and the bladder assembly and is adapted to engage the hinged frame to control movement of the bladder assembly and portions of the foam frame in response to movement of the hinged frame.

In some embodiments, the cover includes a plurality of protrusions extending from an underside of the cover, the protrusions adapted to be received in receptacles formed in portions of the hinged frame to secure the cover to the hinged frame at a plurality of points.

In some embodiments, at least one of the protruding members is secured to the foam frame, and a second at least one of the protruding members is secured to the bladder assembly, and the second at least one protruding member is not secured to the mask body.

In some embodiments, the bladder assembly is secured to the cover at a second location spaced from the projection.

In some embodiments, the cover is configured to include a container (pocket) that receives a portion of the bladder assembly to secure the bladder assembly to the cover in the second position.

In some embodiments, the liner assembly includes a sheet that floats relative to the remainder of the liner assembly, the sheet interconnecting the liner assembly and the cover at the second location.

In some embodiments, the liner assembly includes a sheath formed in the liner assembly housing, and the sheet is positioned in the sheath and movable relative to the sheath.

In some embodiments, the panel is semi-rigid but sufficiently flexible (soft, pliable) to be positioned in the container.

In some embodiments, the second projection member is secured to the bladder casing.

In some embodiments, the first protruding member is connected to a plate secured to the foam frame.

In some embodiments, the slats are secured to the foam frame by a sheath such that the slats float within the sheath.

In some embodiments, the jacket is secured to the foam frame by bonding (gluing, bonding, fitting).

In some embodiments, the foam frame includes a perforated foot portion (section) of variable length.

According to a second aspect of the present disclosure, a patient support device includes a foam frame defining a space; a liner assembly positioned in the space, and a cover surrounding the frame structure and the liner assembly. The bladder assembly includes a plurality of foam filled bladders. Each foam-filled bladder is interconnected by a manifold. The manifold has an unpowered pressure relief valve configured to release air from the bladder assembly if the pressure in the bladder assembly exceeds a predetermined limit of the pressure relief valve. The cover encloses the frame structure and the bladder assembly and is adapted to engage the hinged frame to control movement of the bladder assembly and portions of the foam frame in response to movement of the hinged frame.

In some embodiments, the cover may include a plurality of protrusions extending from an underside of the cover, the protrusions adapted to be received in receptacles formed in portions of the hinged frame to secure the cover to the hinged frame at a plurality of points.

In some embodiments, at least one of the protruding members can be secured to the foam frame, and a second at least one of the protruding members can be secured to the bladder assembly, and the second at least one protruding member is not secured to the mask body.

In some embodiments, the bladder assembly may be secured to the cover at a second location spaced from the projection member.

In some embodiments, the hood may be configured to include a container that receives a portion of the bladder assembly to secure the bladder assembly to the hood at the second location.

In some embodiments, the bladder assembly may include a sheet that floats relative to the remainder of the bladder assembly, and the sheet may interconnect the bladder assembly and the cover at the second location.

In some embodiments, the bladder assembly may include a sheath formed in the bladder assembly casing, and the sheet may be positioned in the sheath and movable relative to the sheath.

In some embodiments, the panels may be semi-rigid but flexible enough to be positioned in a container.

In some embodiments, the second protruding member may be fixed to the bladder casing.

In some embodiments, the first protruding member may be connected to a plate secured to the foam frame.

In some embodiments, the slats may be secured to the foam frame by a sheath such that the slats float within the sheath.

In some embodiments, the jacket may be secured to the foam frame by adhesive.

In some embodiments, the foam frame may include a perforated foot portion of variable length.

In some embodiments, the foam-filled bladders may each include a first layer and a second layer.

In some embodiments, a first group of the plurality of foam-filled bladders may have a first property. The second group in the foam-filled bladder may have a second property that differs from the first property. In some embodiments, the performance difference may cause the support of the patient supported on the patient support device to be different between the head portion and the torso portion of the patient support device.

In some embodiments, each of the bladders may include a transparent window formed in a wall of the casing of the bladder.

In some embodiments, the performance of a particular bladder may be color coded, and the transparent window may be positioned to allow a user to identify the color of the bladder to identify the performance of the particular bladder by correlating the colors.

In some embodiments, some of the plurality of foam-filled bladders may include a non-powered check valve (check valve, one-way valve) configured to open and allow atmospheric air to enter the respective bladder if the pressure in the bladder assembly is lower than the pressure of the atmospheric air.

Additional features, alone or in combination with any other feature(s), such as those listed above and/or those listed in the claims, may constitute patentable subject matter and will become apparent to those skilled in the art upon consideration of the following detailed description of various embodiments exemplifying the best mode of carrying out the embodiments as presently perceived.

Drawings

The detailed description makes reference, in particular, to the appended drawings, in which:

FIG. 1 is a perspective view of a patient support device including a bed frame and a mattress supported on the bed frame;

FIG. 2 is an exploded assembly view of the major components of the mattress of FIG. 1;

FIG. 3 is a detailed exploded assembly view, with parts omitted, of the mattress of FIG. 1, inverted in FIG. 3, and showing the manner in which the components of the mattress are secured together to control movement of the mattress components during movement of the various components of the foundation;

FIG. 4 is an enlarged view of the portion of FIG. 3 enclosed in a circle;

FIG. 5 is an assembled view of the bladder assembly of the mattress of FIG. 1;

FIG. 6 is a top plan view of the bladder assembly of FIG. 5;

FIG. 7 is a right side view of the liner assembly of FIG. 5;

FIG. 8 is a left side view of the bladder assembly of FIG. 5, the bladder assembly being inverted in FIG. 8;

FIG. 9 is a plan view of the liner assembly of FIG. 5;

FIG. 10 is a side view of the liner assembly of FIG. 5, with portions broken away to show the foam structure within the liner;

FIG. 11 is a side view of another bladder of the bladder assembly of FIG. 5, with portions broken away to show a foam structure within the bladder, the foam structure of FIG. 11 being different than the foam structure of FIG. 10;

FIG. 12 is an exploded assembly view of the foam frame of the mattress of FIG. 1;

FIG. 13 is a right side view of the core of the mattress of FIG. 1;

FIG. 14 is a top plan view of a portion of the perforated foot section of the foam frame of the mattress of FIG. 1;

FIG. 15 is a top plan view of a perforated foot portion of the foam frame of the mattress of FIG. 1;

FIG. 16 is a right side view of a perforated foot portion of the foam frame of the mattress of FIG. 1;

FIG. 17 is a perspective view of a projection extending from the bottom cover of the mattress of FIG. 1, the projection configured to engage an opening in a deck member of the bed frame;

FIG. 18 is an illustration of an opening formed in a head deck of the bed frame of FIG. 1, the opening configured to receive the protruding member of FIG. 17;

FIG. 19 is an illustration of an opening formed in a foot deck of the bed frame of FIG. 1, the opening configured to receive the protruding member of FIG. 17; and is

Fig. 20 is a perspective view of the lower shell of the mattress of fig. 1.

Detailed Description

Referring to fig. 1, a patient support device 10 is illustratively embodied as a hospital bed 10. The view shown in fig. 1 is taken generally from a position oriented at the left foot end (tail end) of the hospital bed 10. For orientation purposes, the discussion of the hospital bed 10 will be based on the orientation of a patient supported in a supine position on the hospital bed 10. Thus, the foot end 12 of the hospital bed 10 refers to the end closest to the patient's foot when the patient is supported on the hospital bed 10 in a supine position. The hospital bed 10 has a head end 14 opposite the foot end 12. The left side 16 refers to the left of the patient when the patient is lying in the hospital bed 10 in a supine position. The right side 18 refers to the right of the patient. When referring to the longitudinal length of the hospital bed 10, it refers to the direction indicated by the line extending generally between the head end 14 and the foot end 12 of the hospital bed 10. Similarly, the lateral width of the hospital bed 10 refers to the direction represented by the line extending generally between the left side 16 and the right side 18.

The hospital bed 10 includes a base frame 20 that supports a lift system 22. The lift system 22 engages the base and the upper frame 24 such that the lift system 22 moves the upper frame 24 vertically relative to the base frame 20. The lift system 22 includes a head end link (linkage) 27 and a foot end link 29. The links 27 and 29 are each independently operable and are operable to move the hospital bed 10 to an inclined position when the head end 14 of the upper frame 24 is positioned lower than the foot end 12 of the upper frame 24. The hospital bed 10 can also be moved to an opposite tilt position in which the foot end 12 of the upper frame 24 is positioned lower than the head end 14 of the upper frame 24.

The upper frame 24 supports a load frame 26. The load frame 26 supports a head deck 28 that is movable relative to the load frame 26. The load frame 26 also supports an articulated seat deck 30 and a fixed seat deck 32, which are also movable relative to the load frame 26. A foot deck 34 is also supported by the load frame 26, which is articulated and movable relative to the load frame 26. The foot deck 34 in the exemplary embodiment of fig. 1 provides for powered pivoting of the foot deck 34 and manual extension and retraction of the foot deck 34 to change the length of the foot deck 34. In other embodiments, powered pivoting of the foot deck 34 may be omitted, and the associated movement may occur manually, or follow the movement of the articulated seat deck 30. Additionally, in some embodiments, the extension and retraction of the foot deck 34 may be powered by an actuator.

The foot deck 34 includes a first portion 36 and a second portion 38 that moves relative to the first portion 36 to change the size of the foot deck 34. The second portion 38 moves generally longitudinally relative to the first portion 36 to change the longitudinal length of the foot deck 34, and thus the longitudinal length of the hospital bed 10.

A foot plate 40 is supported by the second portion 38 and extends vertically from an upper surface 42 of the second portion 38 to form a barrier at the foot end 12 of the hospital bed 10. The head plate 44 is positioned on an upright structure 46 of the base frame 20 and extends vertically to form a barrier at the head end 14 of the hospital bed 10. A left head side rail (bed side plate) 48 is supported by the head deck 28 and is movable between a raised position, shown in fig. 1, and a lowered position as is known in the art. The right head side rail 50 is also movable between the raised and lowered positions of fig. 1. As shown in fig. 1, in the raised position, the side rails 48 and 50 extend beyond an upper surface 52 of a mattress 54 of the hospital bed 10 when the side rails 48 and 50 are in the raised position. In the lowered position, the upper edge 56 of the left head side rail 48 is below the upper surface 52.

The hospital bed 10 also includes a left foot side fence 58 and a right foot side fence 60, each supported directly by the load frame 26. Each of the side rails 48, 50, 58 and 60 can be operated to be lowered to a position below the upper surface 52. It should be noted that as the head deck 28 moves, the head side rails 48 and 50 move with the head deck 28 so that the head side rails maintain their relative position with the patient. This is because both head side rails 48 and 50 are supported by the head deck 28.

Referring to fig. 2 and 3, the mattress 54 includes a core 68 containing a bladder assembly 70 engaged with a foam frame 72. The foam frame 72 includes a perforated foot support 62 coupled to a pair of

longitudinal pads

74 and 76. The

longitudinal pads

74, 76 are interconnected by an end plate (head end) 78 that extends transversely between the

pads

74, 76 at the head end 14 of the mattress 54. The core 68 also includes an upper layer of foam 64 and a lower layer of foam 66 that are bonded together to form the upper foam support 65. The

longitudinal pads

74 and 76 are secured to the perforated foot support 62 such that the foot support 62,

pads

74 and 76, end plate 78, and foam support 65 cooperate to define a space 80 in which the bladder assembly 70 is positioned to form the core 68. The mattress 54 includes a lower shell 82 and an upper shell 84 that are secured together with a zipper as is known in the art. The mattress 54 also includes a fire blocking assembly 126 that wraps over the top of the core 68 to completely enclose the core 68 within the fire blocking assembly 126.

As shown in fig. 5 and 6, bladder assembly 70 includes eight

bladders

96, 98, 100, 102, 104, 106, 107, and 108. The bladder is arranged such that bladder 108 is positioned at foot end 12 of bladder assembly 70 and bladder 96 is positioned at head end 14. Each of the

bladders

96, 98, 100, 102, 104, 106, 107, and 108 includes an outer shell 110 of polyurethane coated nylon that provides a gas impermeable shell. As seen in fig. 10 and 11, the interior of each shell 110 is a double-layered foam structure. In fig. 10, the foam structure 112 includes an upper layer 114 and a lower layer 116. Foam layers 114 and 116 are bonded together. The foam structure 112 is capable of deforming under load, but elastically expanding to fill the interior space of the shell 110. Similarly, referring to fig. 11, a different foam structure 142 includes an upper layer 144 bonded to a lower layer 146. The foam material used in

layers

144 and 146 is different than

layers

114 and 116 such that

foam structures

142 and 112 have different performance characteristics. In the exemplary embodiment,

bladders

96, 98, and 100 include foam structure 112, and

bladders

102, 104, 106, 107, and 108 include foam structure 142. These differences serve to provide differential support for the head portion of the liner assembly 70 (including the

liners

96, 98, and 100) relative to the torso portion of the liner assembly 70 (including the

liners

102, 104, 106, 107, and 108).

Referring to fig. 7, 10 and 11, each housing 110 is formed to include a transparent window 148 formed in a wall 150 of the housing 110. Window 148 is positioned to overlie the interface between

layers

114 and 116 or

layers

144 and 146 so that a user can see the material within housing 110. This allows the user to distinguish the contents of the housing 110 to determine which of the

foam structures

112 or 142 is included in the housing 110. In an exemplary embodiment, at least one of the

upper layers

114 or 144 or one of the

lower layers

116 or 146 is a different color. Thus, by comparing the colors visible through the window 148, an assembler can identify the characteristics of a particular shell 110 to determine whether a particular liner should be positioned in the head portion as one of the

liners

96, 98, and 100, or in the torso portion as one of the

liners

102, 104, 106, 107, and 108.

At the left side 16 of each housing 110 there is a pressure relief or check valve 118. Each check valve 118 is configured to open when the pressure applied to the valve exceeds the relief pressure of the valve 118. In the arrangement of the bladder assembly 70, the valves 118 are arranged such that when the pressure within any one of the housings 110 is below atmospheric pressure, the corresponding valve 118 opens to allow air to flow from the atmosphere into the respective housing 110.

On the right side 18 of the liner assembly 70, each housing 110 includes a respective outlet 120. Each of the outlets 120 is connected to a manifold line 122 such that the housings 110 are each in fluid communication with each other through the outlets 120 and the manifold lines 122. Manifold line 122 terminates in a pressure check valve 124. The pressure check valve 124 is configured such that when the pressure in the manifold line exceeds the relief pressure of the check valve 124, the check valve 124 opens to allow the pressure to vent to atmosphere. It should be appreciated that valve 118, which is a check valve, does not allow air to flow from housing 110 through valve 118 to the atmosphere. The only flow path for air from the housing to atmosphere is through manifold line 122 and pressure check valve 124. Similarly, the only path into any of the housings 110 is through the corresponding valve 118.

Thus, mattress 54 is self-regulating to maintain the pressure within each of

bladders

96, 98, 100, 102, 104, 106, 107, and 108 at a pressure below the relief pressure of check valve 124. Operation of the inlet valve 118 for any

particular bladder

96, 98, 100, 102, 104, 106, 107, and 108 that is not loaded provides for rapid filling of the

respective bladders

96, 98, 100, 102, 104, 106, 107, and 108 with air from the atmosphere. This arrangement facilitates relatively rapid regulation of the pressure within each of

bladders

96, 98, 100, 102, 104, 106, 107, and 108 to control the support pressure experienced by the patient.

The pressure venting in the manifold line 122 and pressure check valve 124 allows the patient to be supported on the foam structure 112 of each

bladder

96, 98, 100, 102, 104, 106, 107, and 108 in the event that the patient exceeds the weight that the bladder assembly 70 can be pneumatically supported. In this way, the mattress 54 provides the benefits of a pneumatic mattress, with safety for heavier patients, preventing the patient from bottoming out on the surface of the bed plate of the hospital bed 10. It should be appreciated that when a

particular bladder

96, 98, 100, 102, 104, 106, 107, and 108 is unloaded, the foam structure 112 also serves the purpose of expanding the housing 110 to create a vacuum that draws air through the valve 118.

In the exemplary embodiment of fig. 10,

foam structures

112 and 142 have a similar configuration. However, in some embodiments, layers 114, 116 or 144, 146 of

foam structures

112 and 142 may have different properties in

different bladders

96, 98, 100, 102, 104, 106, 107, and 108, respectively. In addition. In some embodiments, the

foam structure

112, 142 may be a single layer, or may include more than two layers.

Because the bed 10 has a compound articulation of several components, including the movement of the portion 38 of the deck 34 relative to the portion 36, the mattress 54 includes several adaptations that make the mattress 54 suitable for use with the compound articulation. For example, the

longitudinal tie plates

74, 76 are each formed to include a series of relief slits 128 positioned at locations in the

longitudinal tie plates

74, 76 that are positioned at the intersection of the head deck 28 and the articulated seat deck 30. The relief slots 128 provide for expansion of the

longitudinal tie plates

74, 76 as the head deck 28 is raised. With relief slits 128, little material is removed, but the foam is allowed to expand at the location of slits 128. Instead, a series of cutouts 130 are positioned at the interface between the articulated seat deck 30 and the foot deck 34. The cut 130 is generally triangular in shape, with more material being removed at the lower surface 132 of the

longitudinal pads

74, 76, the cut 130 becoming narrower to a termination point spaced from the lower surface 132. The cutout 130 provides for expansion and retraction of the length of the

longitudinal footplates

74, 76 at the interface between the articulated seat deck 30 and the foot deck 34. As the foot deck 34 moves downward relative to the articulated seat deck 30, the removed material at the surface 132 allows the cut-outs 130 to retract so that the material of the

longitudinal tie plates

74, 76 does not bulge.

Bladders

96, 98, 100, 102, 104, 106, 107, and 108 are each positioned within a

respective sheath

156, 158, 160, 162, 164, 166, 168, and 170 of cover 172. The cover 172 is formed of fabric that is stitched to form the

sheaths

156, 158, 160, 162, 164, 166, 168 and 170 as a unitary structure so that during compound articulation of the frame and deck members of the bed 10, some relative movement of the

bladders

96, 98, 100, 102, 104, 106, 107 and 108 is permitted, but the cover 172 maintains the relationship between the

bladders

96, 98, 100, 102, 104, 106, 107 and 108. This prevents

bladders

96, 98, 100, 102, 104, 106, 107, and 108 from being dislodged and maintaining the proper orientation.

To control movement of the mattress 54 relative to the movable members of the bed 10, four protrusions (buttons) 174, 176, 178 and 180 extend from a bottom surface 182 of the lower housing 82, as shown in FIG. 3. The protruding

members

174, 176, 178, and 180 are similarly arranged, and details of the protruding member 174 are shown in FIG. 17, and the protruding member 174 includes a spherical body 182 coupled to a stem 184 extending from a base 186. As shown in fig. 18, the head deck 28 is formed to include a slotted opening 188. The slot-shaped opening 188 is formed using a key-hole effect such that the wider portion 190 narrows to a smaller portion 192. The slotted opening 188 has a longitudinal axis 194 extending transversely across the deck 28, with the slotted opening being positioned such that the wider portion is positioned on the outside of the deck 28. A second slot-shaped opening, which is a mirror image of slot-shaped opening 188, is positioned on the opposite, exterior side of the deck such that tab 178 is positioned in slot-shaped opening 188 and tab 180 is positioned in the mirror-image notch. The natural tendency is for

tabs

178 and 180 to be pushed into the narrower portion 192 of each slot-shaped opening. As shown in fig. 19, another configuration of the keyhole opening 196 is positioned through the surface 42 in the second portion 38 of the bed deck 34. The circular opening 198 is positioned closer to the foot end 12 of the second portion 38, and the protruding

members

174 and 176 are each received in the circular opening 198 of the corresponding keyhole opening 196 such that the post 184 is pushed into the slot 200. When the

prodgers

174, 176, 178, and 180 are engaged with the deck 28 and the deck 34, respectively, movement of the

decks

28, 30, and 34 is directly transferred to the mattress 54 such that the mattress 54 moves with the

decks

28, 30, and 34.

The

projections

174 and 176 are secured to a plate 202, see FIG. 3, which is bonded to the foot end 12 of the perforated foot support 62 by a nut 204 and washer 206 (see FIG. 4), wherein the nut 204 receives the threaded stem 208 of the

projections

174 and 176. The panel 202 is positioned in a sheath 210 that is bonded to the perforated foot support 62 (see FIG. 14). The plate 202 is free to move within the sheath 210 in the direction of arrow 212, as desired.

The protruding

members

178 and 180 are secured to the

respective plates

214 and 216 shown in fig. 3. The cover 172 is formed to include a flap (rim strip) 218, wherein the

plates

214 and 216 are secured to the flap 218 when the

protrusions

178 and 180 are secured by the respective nuts 204. The

panels

214, 216 and the cover 218 cooperate to allow controlled movement of the bladder assembly 70 relative to the lower covering 82. The bladder assembly 70 is further secured to the lower casing 82 by a panel 220 which is positioned within a sheath 222 formed on the bottom of the sheath 170 of the casing 172 of the bladder assembly 70. The plate 220 includes two

flanges

224, 226 that are received in

receptacles

228 and 230, respectively. The

receptacles

228 and 230 are formed in the lower housing 82 by welding material flaps 232, 234 to an upper surface 236 of the lower housing 82. The sheet 220 is flexible (resilient) so that the

flanges

224, 226 can be slid into the

receptacles

228, 230 under the

flaps

232, 234. Thus, at the head end 14, the bladder assembly 70 is secured to the lower shell 82 by the

panels

214, 216 and the

projections

178, 180, and the foot end 12 of the bladder assembly 70 is secured to the lower shell 82 with the

flanges

224, 226 positioned in the

receptacles

228, 230.

During movement of the

deck

28, 30, and 34, the entire mattress 54 is secured by the

protuberances

174, 176, 178, 180, while the bladder assembly 70 is held in place by the

flanges

224, 226 positioned in the

receptacles

228, 230 engaging the

panels

214, 216 and the

protuberances

178, 180. As the second portion 38 of the deck 34 moves relative to the first portion 36, the perforated foot portion 62 is free to expand and contract relative to the bladder assembly 70. This helps control the location of the perforated foot portion 62 and bladder assembly 70 on the appropriate portions of the

deck

28, 30, 32 and 34. Referring now to FIG. 20, a fabric cover piece 238 is welded to the surface 236 of the cover 82 such that a receptacle 240 is formed in an area of the cover 82 that underlies a portion of the perforated foot portion 62. The container 240 receives the plate 242 positioned therein and serves to reinforce that portion of the lower housing 82 that overlies the interface between the first portion 36 and the second portion 38 of the deck 34. This prevents the lower shroud 82 from collecting during movement of the interface between the first portion 36 and the second portion 38 of the deck 34.

Relative movement of the deck 30 and the deck 34, the interface between the perforated foot portion 62 and the bladder assembly 70 is subject to bending (flexing). This bending must be accommodated without allowing the foam members to collect at this interface. The perforated foot portion 62 contains relatively soft foam that provides release for the heel of the patient positioned on the mattress 54. The

foam structures

112 and 142 are relatively rigid to provide support for the patient's seat (buttocks) and torso. Referring to fig. 15 and 16, to accommodate the transition and limit the "drop-down" sensation experienced when a patient is disengaged from the bed 10 as they slide toward the foot end 12 of the bed 10, the perforated foot portion 62 is modified to include a foam block 244 positioned below a cantilevered member 246 extending from a perforated body 248 of the perforated foot portion 62. The foam blocks 244 have a density that provides a stiffness that exceeds the material stiffness of the body 248 and the cantilevered members 246. The foam blocks 244 are formed by removing material so that the

cauls

74, 76 mate with the foam blocks to form scarf joints (rabbet joints). The cantilevered members 246 coincide (overlap ) with the

backing plates

74, 76 to provide a uniform upper surface 250.

Referring again to fig. 3, the lower shell 82 includes several structures formed on the lower surface 182, including four flax locking straps 270, 272, 274 and 276 positioned at four corners. The linen locking straps 270, 272, 274 and 276 are polyurethane coated nylon fabric sewn to the base fabric 286 of the lower shell 82 at each end of the respective straps 270, 272, 274 and 276. The straps 270, 272, 274, and 276 are configured to allow a user to tuck a corner of a linen such as a bed sheet into the straps 270, 272, 274, or 276, for example, to secure the linen under the mattress 54. Similarly, four

handles

278, 280, 282 and 284 are sewn to the base and positioned to allow the user to carry the mattress 54. Two

travel guards

288 and 290 can be positioned over the protruding

members

174, 176 and 178, 180, respectively. The travel guards 288 and 290 comprise foam and are removably secured to the protruding

members

174, 176 and 178, 180, respectively, to cover the protruding

members

174, 176, 178, and 180 to prevent damage to the protruding

members

174, 176, 178, and 180 during transport of the mattress 54.

Although the present disclosure is directed to particular embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the subject matter set forth in the following claims.

Claims

1. A patient support device comprising:

a foam frame defining a space;

a bladder assembly positioned in the space, the bladder assembly comprising a plurality of foam-filled bladders, each of the foam-filled bladders interconnected by a manifold having an unpowered pressure relief valve configured to release air from the bladder assembly if a pressure in the bladder assembly exceeds a predetermined limit of the pressure relief valve; and

a cover enclosing a frame structure and the bladder assembly, the cover adapted to engage a hinged frame to control movement of the bladder assembly and portions of the foam frame in response to movement of the hinged frame;

wherein the cover comprises a plurality of protrusions extending from an underside of the cover, the plurality of protrusions being adapted to be received in receptacles formed in portions of the hinged frame to secure the cover to the hinged frame at a plurality of points;

wherein at least one first protruding member of the plurality of protruding members is fixed to the foam frame, and at least one second protruding member of the plurality of protruding members is fixed to the bladder assembly, and the at least one second protruding member is not fixed to the cover.

2. The patient support device of claim 1, wherein the bladder assembly is secured to the mask body at a second location spaced from the projection member.

3. The patient support device of claim 2, wherein the mask body is configured to include a receptacle that receives a portion of the bladder assembly to secure the bladder assembly to the mask body in the second position.

4. The patient support device of claim 3, wherein the bladder assembly includes a plate that floats relative to a remainder of the bladder assembly, the plate interconnecting the bladder assembly and cover at the second location.

5. The patient support device of claim 4, wherein the bladder assembly includes a sheath formed in a bladder assembly covering, and the plate is positioned in the sheath and movable relative to the sheath.

6. The patient support device of claim 5, wherein the flap is semi-rigid but sufficiently flexible to be positioned in the container.

7. The patient support device of claim 6, wherein the second projection member is secured to the bladder covering.

8. The patient support device of claim 7, wherein the first protruding member is connected to a plate secured to the foam frame.

9. The patient support device of claim 8, wherein the plate is secured to the foam frame by a sheath such that the plate floats within the sheath.

10. The patient support device of claim 9, wherein the sheath is secured to the foam frame by adhesive.

11. The patient support device of claim 10, wherein the foam frame includes a perforated foot portion of variable length.

12. The patient support device of claim 1, wherein the foam-filled bladders each include a first layer and a second layer.

13. The patient support device of claim 12, wherein a first group of the plurality of foam-filled bladders has a first property and a second group of foam-filled bladders has a second property that differs from the first property, and wherein the difference in property causes a difference in support of a patient supported on the patient support device between a head portion and a torso portion of the patient support device.

14. The patient support device of claim 13, wherein each of the bladders includes a transparent window formed in a wall of the shell of the bladder.

15. The patient support device of claim 14, wherein a performance of a particular bladder is color coded and the transparent window is positioned to allow a user to identify a color of the bladder to identify the performance of the particular bladder by correlating the color.

16. The patient support device of claim 1, wherein the foam frame includes a perforated foot portion of variable length.

17. The patient support device of claim 1, wherein each of the plurality of foam-filled bladders includes an unpowered check valve configured to open and allow atmospheric air to enter the respective bladder if the pressure in the bladder assembly is lower than the pressure of atmospheric air.