Note: Descriptions are shown in the official language in which they were submitted.
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The invention relates to a lying-down support or bed mainly
comprising a bottom plate and a plurality of inflatable cushions
supported by said plate and connected through a common feed duct with
a pressure source.
A lying support of this kind is particularly suitable for
persons obliged to stay in bed for a long period, which involves the
hazards of decubitus. Known lying-down supports for preventing and
healing decubitus satisfying the requirements comprise air cushions
arranged in sections in a transverse direction. A specific property
of these cushions is that throu~h pores and seams they permit air to
escape into the atmosphere in order to keep the patient's skin dry. A
drawback of such a system is that the escaping air may contain wound
damp which gives rise to unhygienic conditions. Moreover, the
air-conditioning system, if any, in the patient's room may become
disturbed.
hith the known lying supports the pressure in the air cushions
is set with the aid of a measuring and co~trol-system. This involves
the following inconveniences: when the recumbent person changes his
position, the pressure in each of the cushions has each time to be
reset; in the event o~ damage to one or more air cushions so much air
may escape into the atmosphere that the supply becomes insufficient and
the p~operties of the lying support with regard to the prevention of
decubitus are lost.
According to the invention, there is provided a bed
2~ comprisin~ a bottom plate and a plurality of inflatable cushions
supported transversely on said bottom plate along the length of the
bed and cu~ulatively definin~ the body-supporting surface of the bed,
said cushions bein~ substantially gastight and means for maintaining
gas under pressure internally of said cushions, said means comprisin~
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a gas pressure feed source; a co~mon feed duct connected to said Eeed
source; a main valve in said common feed duct; a plurality of branch
ducts connected downstream of said main valve to said co n feed duct
and connected to distribute gas from said ccmmon feed duct to said
inflatable cushions; a valve in each of said branch ducts whereby
different ones of said cushions may be maintained at different pressures
by isolating at least some of said branch ducts from each other and a
relief valve in said common feed duct downstream of the main valve; a
pressure reducing valve in said ccmmon feed duct for controlling the
pressure of gas supplied by said feed source to said branch ducts; a
pressure sensor in said common ~eed duct; and a computer being connected
to said pressure sensor and for controlling said main valve, relief
valve and valves in each of the branch ducts, such that if said relief
valve is open, gas will be exhausted Erom those cushions connected to
branch ducts whose valves are also open and if said relief valve is
closed, pressurized gas is supplied through said pressure reducing valve
and open main valve to the branch ducts and to those cushions whose
valves are also open, the cc~puter being programmed such as to maintain
the pressure in the cushions, and in the event of a change of position
oE the patient, to set a new pressure ratio in the cushions.
By regular check of the pressure in each cushion or a group of
cushions the control of the valve may take place fully auto~atically so
that at any instant the pressure can be maintained~ In the event o~ a
position change oE the patient, a previously introduced pro~ramme can be
introduced so that the new pressure ratios in the cushions can he very
rapidly set.
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In one embodiment the common feed duct includes a controlled
main valve and is connected at a point aEter the main valve with a
controlled relief valve. By this control all cushions can be very
rapidly provided with pressurized air or they can be separately or
groupwise inflated or emptied.
In a preferred embodiment the common feed duct is provided
with a pressure sensor.
In order to permit the patient to assume more than one
recumbent pOSitiOIl~ a plurality of cushions are united into a section,
which is supported by a carrying plate adjustable in a direction of
height. In this way a sitting position can be obtained, which has in
addition a centering effect on the patient on the bed so that also in a
position change the correct pressure is automatically exerted on the
correct place of the body.
In the preferred embodiment a pneumatic lifting means is
arranged between each carrying plate and the bottom plate, which means
is connected through a branch duct including a controlled valve with the
commcn feed duct. In this way the pressure ratios with respect to the
lying and sitting positions respectively are automatically obtained.
2~ In order to avoid the notorious, undesirable wave motion which
can be particularly troublesome to a patient, each air cushion is
embedded in a U-shaPed support of a foam substance. This support
provides in addition a lateral support, which facilitates getting in and
out of the bed.
If the air pressure should drop-off unexpectedly causing the
cushion to deflate, ~he ~oam-support will act like a normal mattress so
enhancing safety for the patient.
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In order to ensure optimum flexibility of the various cushions
relative to one another, the width of the air cushion is equal to that
of the U-shaped support. This facilitates in addition cleaning of the
lying support.
The invention will be described more fully with reference to a
preferred embodiment. The drawing shows in:
Fig. 1 is a perspective view of the bottom plate with carryinq
plates adjustable in the vertical direction;
Fig. 2 is a perspective view like Fig. 1 of the air cushions
with u-shaPed supports adapted to be deposited on the carrying plates of
Fig. l; and
Fig. 3 is a schematic survey of the pneumatic control-system
for the lying-down support shown in Fig. 1 and 2.
The lying-down support comprises a base part, elements
embedding the air cushionst ai~ cushions, hoses connecting the air
cushions (or groups-of air cushions) with the pressure measuring and
control-system and one or more separation covers holding together the
air cushions and the elements embedding the same.
Fig. 1 illustrates an embodiment of the base par~. This base
part includes a cover 1 holding carryin~ plates 2, the longitudinal
dimensions of which largely correspond to the length of the lcwer legs,
the upeer legs, the pelvis and the remaining upper part of the human
body. Lifting bellcws 3 are located below these carrying plates 2. ~y
pumping air into these bellows various sitting positions as well as
~5 other positions ~or the patient can be obtained. A botto~ plate 4 is
arranged below these lifting bellows 3 and provides a stable substrate
for these bell~s.
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Fig. 2 shows elements embedding the air cushions, the air
cushions, and hoses connecting the air cushions (or groups o~ air
cushions) with the measuring and control-system of the separation cover
or covers. The air cushions 5 are embedded, for example, in foam rubber
blocks 6, which are connected in turn tfor example glued) to the base
part 7.
The standing rims 8 of the relatively stiff foam blocks 6
constitutes rigid side rims left and right of the bed. These side rims
facilitate gettin~ in and out of the bed and can furthermore prevent the
patient from siiding out of the bed.
Each air cushion is provided on one side with a hose 9 for
connection to the pressure measuring and control-system~ The pressure
measuring and control-system may be arranged in a housing below or at
the side of the bed.
In the embodiment shown in Fig 2 the hoses ~ are guided
through the channels lQ towards the side of the lying-dcwn support and
then groupwise interconnected by using a collectin~ block 11. In this
way ~roups of air cushions can be formed. From each collectin~ block 11
a single hose 12 passes towards the pressure measuring and
~0 control-system. As an alternative each hose 9 may be len~thened and
extend up to the pressure measuring and control-system, after which the
yroups are formed.
The air cushion 5 and the foam rubber block 6 can be held
to~ether by a cover. It is not necessary to provide each ccmbination of
cushion and foam rubber block with a separate cover. The construction
t'
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of the cover 13 from a single piece of material has an advanta~e in that
~utters 14 are formed between the air cushions for collectin~ any
incontinency moisture, detergents and so on and conductin~ the same away
towards the side of the lyin~-down support.
In order to protect the bed frame against soilin~ and to cover
the hose 9, 12, flaps 15 may be provided on the left and right-hand side
of the bed.
The pressure measuring and control-system is shown in Fig. 3.
It is desi~ned so that an expert can set for each patient and for each
position of the body the pressures in the separate air cushions (or in
the separate groups of air cushions) and l;fting bellows. The pressure
sequences are then stored in a camputer memory and then they can be set
for each body position by the nurse or the patient himself.
The operation of the pressure measurinq and control-system
will now be described. Compressor 16, stock vessel 17, pressure switch
18, and adjustable reducin~ valve 19 constantly offer pressurized air of
1 to 2 atms. to the input of valve 20. When the pressure has to be
raised in one of the liftin~ bellows or in one of the air cushions,
valve 20 as well as one of the valves 21~ 22 or 23 open. If the
pressure has to be lowered in one of the liftin~ bellows or in one of
the air cushions, valve 24 as well as one of the valves 21, 22 or 23
open.
~f the pressure has to be measured in one of the liftin~
be~lows or in one of the air cushions, all valves are closed with the
exception of th valves 21t 22 or 23. The computer obtains the pressure
information from the pressure sensor 25.
The ahove-~entioned ~ma~netic) valves are actuated by the
micro-computer when:
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- 1. The patient or the nurse inform the micro-computer 2h of
a change of body position and the computer states that the pressures of
the lifting bellows or air cushions associated with the new position
differ from the pressures associated with the earlier position; the
"correct" pressures are - as stated above - stored by the expert in the
computer memory.
2. The computer states during a fully autcmatic, periodic
check, that the pressures of the lifting bellows or air cushions differ
from the corresponding pressures stored in the memory.
0 Thanks to the above-described measuring and control-system the
lying-down support can match patients of hi~hly different body lengths
and various recumbent positions, since ~iven cushions can be without
pressure for short parts of the body. Centerin~ of the patient takes
place automatically when he is brou~ht into a sitting position, in which
case the pelvis is brought to the pelvis-support.
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