U.S. patent number 3,689,945 [Application Number 05/067,504] was granted by the patent office on 1972-09-12 for stretchers.
Invention is credited to Asmund S. Laerdal.
United States Patent |
3,689,945 |
|
September 12, 1972 |
STRETCHERS
Abstract
A stretcher with a vacuum mattress and carrier poles for it, the
vacuum mattress having an air impermeable cover enclosing an
interior which can alternatively be filled with air or evacuated by
a vacuum pump, and which contains a granular material. In order
that it should always be available, independent of human factors,
when the stretcher is used, and should be capable of connection to
the mattress as a preparatory measure, a vacuum pump is mounted in
at least one tubular region of one or both carrier poles.
Inventors: |
Asmund S. Laerdal (Stavanger,
NO) |
Family
ID: |
5744487 |
Appl.
No.: |
05/067,504 |
Filed: |
August 27, 1970 |
Foreign Application Priority Data
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Sep 3, 1969 [DE] |
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19 44 646.9 |
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Current U.S.
Class: |
5/625; 5/913;
5/628 |
Current CPC
Class: |
A61G
1/04 (20130101); A61B 5/103 (20130101); A61G
7/05753 (20130101); Y10S 5/913 (20130101) |
Current International
Class: |
A61G
7/057 (20060101); A61B 5/103 (20060101); A61G
1/00 (20060101); A61G 1/04 (20060101); A61g
001/00 (); A61g 007/10 () |
Field of
Search: |
;5/82,91,348 ;280/201
;417/234-236X,313 ;297/DIG.3 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Casmir A. Nunberg
Attorney, Agent or Firm: Marn & Jangarathis
Claims
I claim:
1. A stretcher comprising: a. two carrier poles, at least one of
said poles having a tubular portion; b. an air impermeable mattress
cover supported by said poles and having an interior zone; c. a
granular material in said interior zone of said mattress cover; and
d. a vacuum pump means in said tubular portion of said pole in
gaseous communication with said interior zone of said mattress
cover for reducing the pressure therein thereby permitting
compression of said granular material within said mattress.
2. A stretcher as claimed in claim 1, wherein said pump includes a
piston, axially reciprocable within said tubular portion.
3. A stretcher as claimed in claim 2, and further comprising an
operating handle connected to said piston and projecting axially
from the associated carrier pole.
4. A stretcher as claimed in claim 2, wherein said piston
cooperates with the interior of the tubular portion, whereby said
tubular portion itself acts as a cylinder.
5. A stretcher according to claim 4, and further comprising a lip
seal carried by said piston and engaging said tubular portion
effective to act as a valve.
6. A stretcher according to claim 2 and further comprising a hollow
piston rod connected to said piston and defining, with said tubular
portion, an annular space therebetween, and means defining an
aperture in said piston rod communicating the hollow interior
thereof with said annular space.
7. A stretcher according to claim 6, and further comprising a
removable end cap to said hollow piston rod, whereby the hollow
interior thereof may be used as a storage space.
8. A stretcher according to claim 1, wherein said mattress cover
further comprises at least one non-return valve.
9. A stretcher according to claim 1, wherein said vacuum pump is
operatively connected to said mattress cover by means of a
hose.
10. A stretcher according to claim 1, wherein the carrier poles are
each formed as at least two parts which are selectively mutually
longitudinally displaceable, said vacuum pump being in an end one
of said parts.
Description
The present invention relates to stretchers.
Stretchers with vacuum mattresses are known in which the interior
of an air impermeable cover, which can alternatively be filled with
air or evacuated, contains a granular material, for example
plastics granules. When the inner space is filled with air, the
granules can be distributed as desired in accordance with external
local pressure influences, whilst with the inner space evacuated it
consolidates under the inward acting pressure of the flexible
covering, in the particular form of distribution which it has
assumed, to give a body which is rigid to an extent varying with
the order of magnitude of the pressure reduction applied. If a
patient is placed on the air-filled vacuum mattress, the granular
material distributes itself in accordance with the contour of the
body. As a result of subsequent evacuation, the granular material
consolidates in the form which it has assumed and hence provides a
firm hold, acting over a large area and secure against
displacements, for the patient on the stretcher, and with this hold
it is possible to transport the patient without hazard and without
painful pressure even if the stretcher is in an inclined
position.
According to the present invention there is provided a stretcher
comprising two carrier poles, an air impermeable mattress cover
supported by said poles and provided with a granular filling, and a
vacuum pump in a tubular portion of at least one of said poles and
operatively connected to the interior of said mattress cover.
With the stretcher of the present invention it is not necessary to
employ a separate vacuum pump as has previously been used, and
which had to be transported independently of the stretcher and had
to be connected to the mattress, at the place where the patient was
being collected, by means of a hose. Transporting the pump as an
independent unit necessitated the use of a hand which would
otherwise be free, and did not exclude the possibility of the
stretcher and the pump not arriving simultaneously at the point
where the patient was collected, which could result in loss of
valuable time, frequently vital for saving the patient. The latter
is in particular also true if the pump could, for technical reasons
relating to its transportation, only be connected to the mattress
at the site of the accident.
With a stretcher of the invention the vacuum pump is always
available and can be connected to the mattress as a preparatory
measure without the transportation of the stretcher thereby being
made more involved and requiring additional hands to hold it.
In the simplest embodiment of the stretcher according to the
invention, only one of the carrier poles is provided with a vacuum
pump. Of course it is also possible to provide several pumps for
one stretcher, for example one pump in each carrier pole or two
pumps in one carrier pole which can, in view of the relative forces
which arise, be operated simultaneously by two persons in opposite
working cycles. The carrier poles are tubular either completely or
at least in the region of the vacuum pump, so that a simple vacuum
pump, operating with a reciprocable piston, can be incorporated in
the inner space of the pole.
The pump can in this case fundamentally be inserted into the
carrier pole as a self-contained component. In a preferred
embodiment, however, the wall of the tubular region of the pole is
constructed as a cylinder, the piston being guided along its inner
wall. This provides as large a stroke volume as possible for a
given external diameter of the pole and a predetermined length of
stroke of the pump. Furthermore the weight and the space
requirement of the pump are reduced.
It is possible to operate the piston by means of an actuating
handle which projects laterally from the wall of the tubular
region, as a result of which the piston stroke movement would not
extend beyond the length of the pole. In a particularly preferred
embodiment of the invention, however, the handle is arranged so
that it can be drawn out of the end face of the pole, since this
simplified guiding the piston and the handle and does not weaken
the carrier pole.
In the stretcher according to the invention, the carrier poles can
be integrally or detachable connected to the vacuum mattress. In
the former case, in particular, it is possible to connect the
suction chamber of the pump directly to an orifice in the cover. In
this case, a non-return valve which seals off the interior of the
cover can conveniently be provided at the pump outlet. With carrier
poles which are detachable from the mattress, it is advisable to
provide a flexible, detachable hose connection between the suction
chamber of the pump and the orifice of the cover, this hose
connection being capable of following possible displacements or
different connecting positions between the pole and the mattress,
and facilitating connection as desired. For this reason, it is also
possible to carry hoses of different lengths with the stretcher, in
order to be able to do justice to different arrangements of the
mattress. In particular, with the detachable connection between the
suction chamber and the pump, the non-return valve is preferably
provided on the orifice or orifices of the mattress, so that the
mattress can be transported separately from the carrier poles, and
possibly in a narrow space, whilst maintaining the evacuated
condition.
Again, for technical reasons relating to transportation, it may be
advantageous to use carrier poles which consist of at least two
parts, displaceable relative to one another in the longitudinal
direction. Thus, for example, one part of the pole can be pushed
into another tubular part of the pole, at the free end of which the
pump is located. By pushing one part of the pole into the other,
the total length of the carrier pole can be changed so that the
stretcher, with the patient strapped to it, can be more
conveniently transported through narrow staircases or in small
passenger lifts. In the latter case, a particular position of the
body of the patient is frequently necessary, which can only be
brought about if the stretcher is appropriately shortened, in order
to be able to carry out requisite heart massages at short
intervals.
In order that the invention will be better understood, the
following description is given, merely by way of example, reference
being made to the accompanying drawing, in which:
FIG. 1 is a schematic perspective view of one embodiment of the
stretcher according to the invention, on which a patient is placed;
and
FIG. 2 shows a schematic representation, in cross-section, of a
vacuum pump of the stretcher of FIG. 1.
In the embodiment of the stretcher represented in FIG. 1, the
vacuum mattress 1 is detachably supported by the carrier poles 3
and 4 by means of straps 2. The drawing shows how the mattress 1
which has been air-filled -- for example through one of the air
passage orifices 5 or a shut-off valve -- can easily deformably be
adapted to the body shape and limb positions of the patient. If the
knees are bent, the patient can thereby even be transported in a
sitting position.
With the aid of the vacuum pump 7 carried in a hollow end region 6
of the carrier pole 3, air can be pumped out of the flexible
covering 8 after having fastened the patient to the appropriately
deformed mattress 1. The connection between the pump and one of the
orifices 5, provided with non-return valves, in the covering 8 is
not shown. As already described, the granular material contained in
the covering and distributed in accordance with the contact
surfaces of the mattress with the body of the patient, is more or
less firmly compressed, through the action of the covering which is
compressed by atmospheric pressure, depending on the order of
magnitude of the vacuum achieved in the covering, so as to maintain
its distribution and retain the shape. The stretcher is now ready
for transporting the patient. By virtue of the detachable
connection between the mattress and the carrier poles and the
non-return valve in the orifice 5, the mattress 1 can at any time
be separated from the carrier poles 3 and 4 and hence also from the
vacuum pump 7, without air entering and the shape retention of the
mattress thereby being lost.
The vacuum pump 7, formed in the end region 6 of the carrier pole
3, is shown in schematic cross-section in FIG. 2. The wall 9 of the
tubular region 6 of the carrier pole 3 at the same time serves as
the cylinder for the piston 10 of the pump, carried therein, which
is connected through its piston rod 11 with an operating handle 12
projecting from the end face of the end region 6 of the pole 3. The
piston 10 carries a lip seal 13, which opens or closes depending on
the pressure difference on the two sides of the piston and hence
forms, in addition to the non-return valve in the air passage
orifice 5 of the covering 8, the second valve required for
operation of the pump. The piston rod 11 is hollow and is connected
at its piston end, via an orifice 14, with the annular space 15
between the cylinder and the piston rod. The cavity 16 of the
piston rod 11 is in turn connected to the atmosphere via an outlet
17. The piston rod 11 is particularly resistant to bending because
of its hollow form and hence contributes to a reduction in weight,
without the output space of the pump being impaired.
The suction space 19 of the pump, formed in front of the piston 10
and shut off at 18, is connected via a connecting orifice 20 and a
pipeline shown in broken lines, with the orifice 5 of the covering
8. One or more hoses, which can also be of different length, for
adaptation to different mattresses or their intended shape, can be
stored in the cavity 16 of the piston rod 11, which is for example
accessible by undoing the actuating handle 12, which can be in the
form of a detachable end cap.
The broken arrows at 20, 14 and 17 show the flow of air during the
suction stroke, which results from pulling the handle 12 away from
the end region of the pole 3, in its longitudinal direction. When
the piston is returned, the non-return valve in the orifice 5 of
the covering 8 closes, so that a pressure is built up in the
suction chamber 19 and the lip seal 20 opens in the direction of
the output space 15, 16 of the pump and allows the accumulated air
to pass through. When the handle 12 is again pulled, a reduced
pressure relative to the pressure in the output space 15, 16
results in the suction chamber 19, so that the lip seal rests
against the cylinder inner wall to form a seal, as a result of
which the flow of air indicated by the broken arrows again
results.
* * * * *