U.S. patent application number 10/634107 was filed with the patent office on 2005-02-10 for lightweight decontaminable composite stretcher.
Invention is credited to Castellani, Robert, Ling, Leon.
Application Number | 20050028283 10/634107 |
Document ID | / |
Family ID | 33565205 |
Filed Date | 2005-02-10 |
United States Patent
Application |
20050028283 |
Kind Code |
A1 |
Castellani, Robert ; et
al. |
February 10, 2005 |
LIGHTWEIGHT DECONTAMINABLE COMPOSITE STRETCHER
Abstract
A stretcher comprising a molded frame assembly having a first
frame pole and a second frame pole interconnected by a spreader bar
for maintaining poles in a laterally spaced arrangement. A bed
member is carried by the frame poles adapted for receiving and
supporting a person. The molded frame assembly is constructed of a
composite of 50% to 85% polyamide resin and 15% to 50% fiberglass
by weight to resist hazardous materials and allow for
decontamination of the frame assembly. The frame poles are
constructed from a plurality of frame arms. A hinge pivotally
connects abutting ends of frame arms, and a hinge support carried
opposite the hinge further interconnects frame arms to increase the
structural rigidity of the hinge. The frame poles having a hollow
interior cavity to reduce weight with reinforcing members disposed
in the cavity running the length of the cavity to resist bending
and twisting.
Inventors: |
Castellani, Robert; (Easley,
SC) ; Ling, Leon; (Singapore, SG) |
Correspondence
Address: |
Seann P. Lahey
McNair Law Firm, P.A.
P.O. Box 10827
Greenville
SC
29603
US
|
Family ID: |
33565205 |
Appl. No.: |
10/634107 |
Filed: |
August 4, 2003 |
Current U.S.
Class: |
5/627 |
Current CPC
Class: |
Y10T 16/551 20150115;
A61G 1/013 20130101; Y10T 16/531 20150115; Y10T 16/526
20150115 |
Class at
Publication: |
005/627 |
International
Class: |
A47B 001/00 |
Claims
What is claimed is:
1. A lightweight decontaminable stretcher for transporting injured
persons and persons exposed to hazardous materials, comprising: a
molded frame assembly having a first frame pole and a second frame
pole interconnected by a spreader bar for maintaining said first
and second frame poles in a laterally spaced arrangement; a bed
member carried by said first and second frame poles adapted for
receiving and supporting a person between said frame poles; and,
said molded frame assembly constructed of a composite of 50% to 85%
by weight of a polyamide resin containing 15% to 50% fiberglass by
weight to resist hazardous materials and allow for decontamination
of said frame assembly.
2. The stretcher of claim 1 wherein said polyamide resin is
selected from the group consisting of polycaprolactam (nylon 6),
polytetramethylene adipamide (nylon 4/6), polyhexamethylene
adipamide (nylon 6/6), polyhexamethylene sebacamide (nylon 6/10),
polyhexamethylene dodecamide (nylon 6/12), polyundecamethylene
adipamide (nylon 11/6), polyundecalactam (nylon 11),
polydodecalactam (nylon 12), polytrimethylhexamethylene
terephthalamide (nylon TMHT), polyhexamethylene isophthalamide
(nylon 61), polynonanemethylene terephthalamide (9T),
polyhexamethylene terephthalamide (6T), polybis
(4-aminocyclohexyl)methane dodecamide (nylon PACM12),
polybis(3-methyl-aminocyclohexyl)methane dodecamide (nylondimethyl
PACM12), polymethaxylylene adipamide (nylon MXD6) and
polyundecamethylene hexahydroterephthalamide (nylon 11T(H)) and
polyamide copolymers, and mixtures thereof.
3. The stretcher of claim 1 wherein said first frame pole and said
second frame pole are constructed from a plurality of frame arms
pivotally connected for moving between a folded configuration
wherein said frame arms for each pole are generally stacked upon
each other, and an unfolded configuration wherein said frame arms
are aligned end to end in a common plane to form each of said frame
poles.
4. The stretcher of claim 3 including a hinge pivotally connecting
abutting ends of said frame arms, and a hinge support carried
opposite said hinge interconnecting abutting ends of said frame
arms when in said unfolded configuration, and said hinge support
disengaging abutting ends of said frame arms to allow said frame
arms to move to said folded configuration.
5. The stretcher of claim 4 wherein said hinge includes a first
hinge portion carried by a distal end of a first frame arm, and a
second hinge portion carried by an abutting distal end of a second
frame arm; said first and second hinge portions have a plurality of
spaced hinge projections forming a series of hinge slots; said
hinge projections engaging said hinge slots of the abutting frame
arm so that said hinge projections of said first and second frame
arms overlap; and a pivot pin pivotally connecting overlapping
hinge projections from said first and second hinge portion.
6. The stretcher of claim 5 wherein said hinge support includes a
first support portion carried by said distal end of said first
frame arm opposite said first hinge portion, and a second support
portion carried by said abutting distal end of said second frame
arm opposite said second hinge portion; said first and second
support portions have a plurality of spaced support projections
forming a series of support slots; said support projections
engaging said support slots of the abutting frame arm when in said
unfolded configuration so that said support projections
interconnect abutting ends of frame arms to resist twisting of said
frame arms.
7. The stretcher of claim 6 wherein each of said frame arms
includes an interior cavity running the length of said frame arm,
and at least one rib member molded into said frame arm protruding
from an interior surface of said frame arm into said interior
cavity and generally running the length of said interior cavity to
restrict bending and twisting of said frame arm.
8. The stretcher of claim 7 including at least one cross member
molded into said frame arm extending through said interior cavity
from said interior surface of said frame arm and generally running
the length of said interior cavity to restrict bending and twisting
of said frame arm.
9. A lightweight decontaminable stretcher for transporting injured
persons and persons exposed to hazardous materials, comprising: a
foldable molded frame assembly for carrying a bed member adapted to
receive and support a person; a first frame pole and a second frame
pole included in said frame assembly constructed from a plurality
of frame arms; a hinge pivotally connecting abutting ends of said
frame arms for moving between a folded configuration and an
unfolded configuration; a hinge support carried opposite said hinge
for interconnecting abutting ends of said frame arms when in said
unfolded configuration, and said hinge support disengaging abutting
ends of said frame arms to allow said frame arms to move to said
folded configuration; and, a spreader bar included in said frame
assembly interconnecting said first and second frame poles.
10. The stretcher of claim 9 wherein said molded frame assembly is
constructed of a composite of 50% to 85% by weight of a polyamide
resin containing 15% to 50% fiberglass by weight to resist
hazardous materials and allow for decontamination of said frame
assembly.
11. The stretcher of claim 9 wherein said hinge includes a first
hinge portion molded into a distal end of a first frame arm, and a
second hinge portion molded into an abutting distal end of a second
frame arm; said first and second hinge portions have a plurality of
spaced hinge projections forming a series of hinge slots; said
hinge projections engaging said hinge slots of the abutting frame
arm so that said hinge projections of said first and second frame
arms overlap; and a pivot pin pivotally connecting overlapping
hinge projections from said first and second hinge portion.
12. The stretcher of claim 11 wherein said hinge support includes a
first support portion molded into said distal end of said first
frame arm opposite said first hinge portion, and a second support
portion molded into said abutting distal end of said second frame
arm opposite said second hinge portion; said first and second
support portions have a plurality of spaced support projections
forming a series of support slots; said support projections
engaging said support slots of the abutting frame arm when in said
unfolded configuration so that said support projections
interconnect abutting ends of frame arms to resist twisting of said
frame arms.
13. The stretcher of claim 9 wherein each of said frame arms
includes an interior cavity running the length of said frame arm,
and at least one rib member molded into said frame arm protruding
from an interior surface of said frame arm into said interior
cavity and generally running the length of said interior cavity to
restrict bending and twisting of said frame arm.
14. The stretcher of claim 9 wherein each of said frame arms
includes an interior cavity running the length of said frame arm,
and at least one cross member molded into said frame arm extending
through said interior cavity from an interior surface of said frame
arm and generally running the length of said interior cavity to
restrict bending and twisting of said frame arm.
15. A lightweight decontaminable stretcher for transporting injured
persons and persons exposed to hazardous materials, comprising: a
frame assembly having a first frame pole and a second frame pole
interconnected by a spreader bar for maintaining said first and
second frame poles in a laterally spaced arrangement; a bed member
carried by said first and second frame poles adapted for receiving
and supporting a person between said frame poles; said first and
second frame poles having a hollow interior cavity to reduce
weight; and, at least one reinforcing member formed on an interior
surface of said frame poles within said hollow interior cavity and
generally running the length of said hollow interior cavity to
strengthen the rigidity of said frame poles to resist bending and
twisting.
16. The stretcher of claim 15 wherein said reinforcing member
includes a rib member molded into said frame pole protruding from
an interior surface of said frame pole into said interior cavity
and generally running the length of said interior cavity to
restrict bending and twisting of said frame pole.
17. The stretcher of claim 15 wherein said at least one reinforcing
member includes a cross member molded into said frame pole
extending through said interior cavity from said interior surface
of said frame pole and generally running the length of said
interior cavity to restrict bending and twisting of said frame
pole.
18. The stretcher of claim 15 including a plurality of reinforcing
members comprising at least one rib member molded into said frame
pole protruding from an interior surface of said frame pole into
said interior cavity and generally running the length of said
interior cavity to restrict bending and twisting of said frame
pole, and at least one cross member molded into said frame pole
extending through said interior cavity from said interior surface
of said frame pole and generally running the length of said
interior cavity to restrict bending and twisting of said frame
pole.
19. The stretcher of claim 15 wherein said molded frame assembly is
constructed of a composite of 50% to 85% by weight of a polyamide
resin containing 15% to 50% fiberglass by weight to resist
hazardous materials and allow for decontamination of said frame
assembly.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to litters, stretchers, cots,
and the like, and more particularly, to a reinforced lightweight
composite stretcher specifically capable of being decontaminated
from chemical and biological warfare agents, as well as other
hazardous materials.
BACKGROUND OF THE INVENTION
[0002] The prior art is replete with various types of stretchers.
However, none of these stretchers were designed to be resistant to
the types of chemical and biological warfare agents available today
sufficient to be decontaminated when exposed to such severely
hazardous material.
[0003] For example, U.S. Pat. No. 5,598,592, discloses a stretcher
for allowing decontamination of a person while on the stretcher
without having to remove the person from the stretcher. The frame
is made from metal or wood tubular poles painted with a chemical
resistant paint, and the hand grips, which are inserted into the
poles are constructed using nylon 6/6. While this construction will
resist moderately hazardous material, more dangerous hazardous
materials such as VX nerve gas, and other chemical and biological
warfare agents, easily penetrate the painted metal or wood poles,
rendering the stretcher useless after carrying its first
contaminated person. Additionally, there is no teaching of the
handles being constructed in a manner sufficient to be
decontaminated on site from potent chemical and biological warfare
agents.
[0004] British Patent No. 488,504 discloses a litter in which the
frame members are constructed of metal tubing closed at the ends so
as to be impervious to gas to a higher degree than other litters of
the time (1938). Again, today's chemical and biological warfare
agents easily penetrate into the metal, highly contaminating the
litter and making field decontamination impossible for continued
use of the litter. This invention was simply not directed to
solving the problem of direct penetration of the litter frame by
hazardous materials.
[0005] U.S. Pat. No. 5,263,213; 3,417,412; 6,526,611; and 5,572,756
disclose stretchers which may be constructed using a variety of
materials such as fiberglass or plastic. However, there is no
disclosure of any of the stretchers being constructed from a
lightweight composite material resistant to chemical and biological
warfare agents so as to be decontaminable, while also being strong
enough to support the weight of a person.
[0006] Accordingly, it is an object of the present invention to
provide a stretcher capable of resisting severely hazardous
materials such as chemical and biological warfare agents sufficient
to allow for on site decontamination of the stretcher while
carrying a person so that the stretcher may continue to be used
without further contamination to the users.
[0007] It is an object of the present invention to provide a
foldable stretcher to facilitate transport and storage of the
stretcher when not in use.
[0008] It is an object of the present invention to provide a
lightweight composite frame for a stretcher which is reinforced to
resist bending and twisting when carrying a person.
SUMMARY OF THE INVENTION
[0009] The above objectives are accomplished according to the
present invention by providing a lightweight decontaminable
stretcher for transporting injured persons and persons exposed to
hazardous materials comprised of the elements set forth below. The
stretcher includes a molded frame assembly having a first frame
pole and a second frame pole interconnected by a spreader bar for
maintaining the first and second frame poles in a laterally spaced
arrangement. A bed member is carried by the first and second frame
poles which is adapted for receiving and supporting a person
between the frame poles. In the preferred embodiment, the molded
frame assembly is constructed of a composite of 50% to 85% by
weight of a polyamide resin containing 15% to 50% fiberglass by
weight to resist hazardous materials and allow for decontamination
of the frame assembly. Preferably, the polyamide resin used in
constructing the frame assembly is polyhexamethylene adipamide
(nylon 6/6), which provides excellent resistance to chemical and
biological warfare agents.
[0010] The first frame pole and the second frame pole are
constructed from a plurality of frame arms pivotally connected for
moving between a folded configuration wherein the frame arms for
each pole are generally stacked upon each other, and an unfolded
configuration wherein the frame arms are aligned end to end in a
common plane to form each of the frame poles.
[0011] A hinge pivotally connects abutting ends of the frame arms,
and a hinge support carried opposite the hinge further
interconnects abutting ends of the frame arms when in the unfolded
configuration to increase structural rigidity of the hinge. The
hinge support disengages abutting ends of the frame arms to allow
the frame arms to move to the folded configuration.
[0012] The hinge includes a first hinge portion carried by a distal
end of a first frame arm, and a second hinge portion carried by an
abutting distal end of a second frame arm. The first and second
hinge portions have a plurality of spaced hinge projections forming
a series of hinge slots. The hinge projections engage the hinge
slots of the abutting frame arm so that the hinge projections of
the first and second frame arms overlap. A pivot pin is used to
pivotally connect overlapping hinge projections from the first and
second hinge portion.
[0013] The hinge support includes a first support portion carried
by the distal end of the first frame arm opposite the first hinge
portion, and a second support portion carried by the abutting
distal end of the second frame arm opposite the second hinge
portion. The first and second support portions have a plurality of
spaced support projections forming a series of support slots. The
support projections engage the support slots of the abutting frame
arm when in the unfolded configuration so that the support
projections interconnect abutting ends of frame arms to resist
twisting of the frame arms.
[0014] Advantageously, each of the frame arms includes an interior
cavity running the length of the frame arm with at least one rib
member molded into the frame arm protruding from an interior
surface of the frame arm into the interior cavity and generally
running the length of the interior cavity to restrict bending and
twisting of the frame arm. Alternatively, or in addition to, at
least one cross member is molded into the frame arm extending
through the interior cavity from the interior surface of the frame
arm and generally running the length of the interior cavity to
restrict bending and twisting of the frame arm.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The construction designed to carry out the invention will
hereinafter be described, together with other features thereof. The
invention will be more readily understood from a reading of the
following specification and by reference to the accompanying
drawings forming a part thereof, wherein an example of the
invention is shown and wherein:
[0016] FIG. 1 shows a perspective view of the stretcher according
to the invention;
[0017] FIG. 2 shows an exploded view of a hinge according to the
invention;
[0018] FIG. 3a shows a completed hinge according to the
invention;
[0019] FIG. 3b shows an end view of a frame pole in an unfolded
configuration allowing use of the stretcher;
[0020] FIG. 3c shows an end view of a frame pole rotated to allow
folding of the stretcher;
[0021] FIG. 3d shows a hinge pivoted open to allow the stretcher to
be place in the folded configuration;
[0022] FIG. 4a shows a cross-section view of a frame member having
reinforcing rib and cross members;
[0023] FIG. 4b shows a cross-section view of a frame member having
a reinforcing cross member;
[0024] FIG. 4c shows a cross-section view of a frame member having
a plurality of reinforcing rib members.
[0025] FIG. 5a shows a top view of the stretcher in the unfolded
configuration;
[0026] FIG. 5b shows rotation of the frame poles prior to folding
the stretcher;
[0027] FIG. 5c shows a top view of the stretcher with the spreader
bars retracted;
[0028] FIG. 5d shows a side view of the stretcher in the unfolded
configuration;
[0029] FIG. 5e shows a side view of the stretcher being folded;
and
[0030] FIG. 5f shows a side view of the stretcher in the folded
configuration.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] With reference to the drawings, the invention will now be
described in more detail. In this patent the term "hazardous
materials" specifically includes chemical and biological warfare
agents, along with hazardous, dangerous and otherwise unsafe
chemicals requiring a person to be decontaminated after expose,
radioactive or poisonous elements, and human bodily fluids.
Referring to FIG. 1, a lightweight decontaminable stretcher,
designated generally as A, is shown for transporting injured
persons and persons exposed to hazardous materials. In the
preferred embodiment, stretcher A includes a molded frame assembly
having a first frame pole, designated generally as 10, and a second
frame pole, designated generally as 12. Frame poles 10 and 12 are
interconnected by spreader bars 14a and 14b (best shown in FIG. 5a)
for maintaining first frame pole 10 and second frame poles 12 in a
laterally spaced arrangement. As described in detail below,
spreader bars 14a and 14b may be retracted to draw the frame poles
closer together to configure the stretcher between an unfolded
configuration (FIG. 5a) and a folded configuration (FIG. 5f),
providing for easy storage and transportation when folded.
[0032] A bed member 16 is carried by the first and second frame
poles which is adapted for receiving and supporting a person
between frame poles 10 and 12. In a preferred embodiment, bed 16 is
constructed of a large mesh of monofilament polypropylene,
polyester, polyamide, or a blend thereof, which is resistant to
hazardous materials and may easily and safely decontaminated. The
large mesh bed prevents the patient from slipping on or from the
bed while being carried or while being decontaminated.
Additionally, the large mesh allows for the decontamination of the
patient while on the stretcher without the risk of creating hot
spots of hazardous materials where the patient is in contract with
the bed. Such hot spots are a risk when solid surface materials,
such as backboards, are used to support the patient during
decontamination. The present invention eliminated this problem.
[0033] Advantageously, the molded frame assembly, defined as frame
poles 10 and 12 together with spreader bars 14a and 14b, is
constructed of a composite of 50% to 85% by weight of a polyamide
resin containing 15% to 50% fiberglass by weight to resist
hazardous materials. The composite provides the necessary
resistance to chemical and biological warfare agents, such as VX
nerve gas, to allow for decontamination of the frame assembly
sufficient to allow continued use of the stretcher without the risk
of further contamination to the person being carried on the
stretcher, or to persons carrying the stretcher. The polyamide
resin is selected from the group consisting of polycaprolactam
(nylon 6), polytetramethylene adipamide (nylon 4/6),
polyhexamethylene adipamide (nylon 6/6), polyhexamethylene
sebacamide (nylon 6/10), polyhexamethylene dodecamide (nylon 6/12),
polyundecamethylene adipamide (nylon 11/6), polyundecalactam (nylon
11), polydodecalactam (nylon 12), polytrimethylhexamethylene
terephthalamide (nylon TMHT), polyhexamethylene isophthalamide
(nylon 61), polynonanemethylene terephthalamide (9T),
polyhexamethylene terephthalamide (6T), polybis
(4-aminocyclohexyl)methane dodecamide (nylon PACM12),
polybis(3-methyl-aminocyclohexyl)methane dodecamide (nylondimethyl
PACM12), polymethaxylylene adipamide (nylon MXD6) and
polyundecamethylene hexahydroterephthalamide (nylon 11T(H)) and
polyamide copolymers, and mixtures thereof. Preferably, the
polyamide resin used in constructing the frame assembly is
polyhexamethylene adipamide (nylon 6/6), mixed at a ration of 65%
nylon and 35% fiberglass by weight, which provides excellent
resistance to known chemical and biological warfare agents. As an
added benefit, the molded composite frame assembly is extremely
durable and considerably lighter than other stretcher of comparable
design which are typically made of metal. Preferably, the composite
frame poles are formed through and injection molding process, as is
commonly known to a person skilled in the art.
[0034] Referring to FIG. 5a, first frame pole 10 is constructed
from a plurality of frame arms 18a-d that are pivotally connected.
Second frame pole 12 is similarly constructed from a plurality of
frame arms 18e-h, which are also pivotally connected. The pivotally
connected frame arms allow the stretcher to move between the
unfolded configuration shown in FIG. 5a, wherein the frame arms are
aligned end to end in a common plane to form each of frame poles 10
and 12, and the folded configuration as shown in FIG. 5f, wherein
the frame arms for each of poles 10 and 12 are aligned side to side
and generally stacked upon each other to allow for easy storage and
transportation.
[0035] Referring to FIG. 1, a hinge 20 provides the pivotal
connection between abutting ends of frame arms 18a-h.
Advantageously, a hinge support 22 is carried by the frame arms
opposite hinge 20 for further interconnecting abutting ends of the
frame arms when in the unfolded configuration to increase the
structural rigidity of hinge 20 to prevent bending and twisting of
the hinge when carrying the weight of a person. As best shown in
FIG. 3d, hinge support 22 also disengages and separates to allow
abutting ends of the frame arms opposite hinge 20 to pivot so that
the frame assembly can be moved to the folded configuration, as
described in more detail below. Hinge support 22 is necessary to
reinforce each hinge so that the lightweight composite material
will not break at hinge 20 under heavy loads. Effectively, hinge
support 22 doubles the strength of hinge 20 by equally distributing
forces between hinge 20 and hinge support 22 through the specific
structure of hinge 20 and hinge support 22 described herein.
[0036] Referring to FIGS. 2 and 3a, hinge 20 includes a first hinge
portion, designated generally as 24, carried by a distal end 25 of
a first frame arm 18a. It is to be understood that the construction
described here applies to all hinges between abutting ends of any
of frame arms 18a-h. A second hinge portion, designated generally
as 26, is carried by an abutting distal end 27 of a second frame
arm 18b. First hinge portion 24 has a plurality of spaced hinge
projections 28a forming a series of hinge slots 30a. Second hinge
portion 26 has a plurality of complementary spaced hinge
projections 28b forming a series of complementary hinge slots 30b.
Hinge projections 28a engage hinge slots 30b at distal ends 25 and
27 of abutting frame arms 18a and 18b, respectively, as shown in
FIG. 3b, so that hinge projections 28a of frame arm 18a overlap
hinge projections 28b of frame arm 18b, as best shown in FIGS. 1
and 3b. Referring to FIGS. 2 and 3b, a pivot pin 32 is used to
pivotally connect overlapping hinge projections 28a and 28b from
first hinge portion 24 and second hinge portion 26 to provide the
completed hinge 20.
[0037] Referring to FIGS. 2 and 3a, hinge support 22 includes a
first support portion, designated generally as 34, carried by
distal end 25 of first frame arm 18a, opposite first hinge portion
24. Again, it is to be understood that the following arrangement
applies to all hinge supports between abutting ends of any of frame
arms 18a-h. A second support portion, designated generally as 36,
is carried by abutting distal end 27 of second frame arm 18b,
opposite second hinge portion 26. First support portion 34 has a
plurality of spaced support projections 38a forming a series of
support slots 40a. Second support portion 36 has a plurality of
complementary spaced support projections 38b forming a series of
complementary support slots 40b. Support projections 38a engage
support slots 40b at distal ends 25 and 27 of abutting frame arms
18a and 18b, respectively, as shown in FIG. 3a, so that support
projections 38a of frame arm 18a overlap support projections 38b of
frame arm 18b to interconnect abutting ends 25 and 27 of frame arms
18a and 18b to resist twisting of the frame arms when the stretcher
is in the unfolded configuration, represented in FIGS. 1 and
5a.
[0038] In the preferred embodiment, spreader bar 14a, as well as
spreader bar 14b, interconnect frame poles 10 and 12 by way of
accessory bracket 42. As shown in FIGS. 2 and 3a, spreader bar 14a
is hingedly connected to accessory bracket 42 by pivot pin 43 at a
pivot point, designated generally as 45. Accessory bracket 42 is
used for attaching items such as wheels, stands, legs, and other
items that may be used in combination with the stretcher. Accessory
bracket 42 is then further hingedly connected to frame arm 18a
using pivot pin 44 at a second pivot point, designated generally as
46. This connection is repeated at each end of spreader bars 14a
and 14b to interconnect the spreader bars with the various frame
arms comprising the frame poles.
[0039] The pivoting connection between the spreader bars, accessory
brackets, and frame arms is necessary to allow for folding of the
frame assembly, while also allowing the frame arms to be locking in
the unfolded configuration to prevent collapse of the frame poles
when carrying a person. Referring to FIG. 3b, when the frame
assembly is in the unfolded configuration of FIG. 5a, hinge 20 and
hinge support 22 are oriented in a vertical alignment and will not
pivot when the stretcher is picked up. Spreader bars 14a and 14b
further prevent the hinges from pivoting laterally. Accordingly, in
order to fold the frame arms into the folded configuration of FIG.
5f, frame poles 10 and 12 must be pivoted to align hinges 20 in a
lateral arrangement which will allow the frame arms to be folded
together. As best shown in FIGS. 3c and 5b, the frame poles are
first pivoted on pivot points 46 so that hinges 20 are rotated
90.degree. from the vertical alignment in the unfolded
configuration shown in FIG. 3b. Next, as shown in FIG. 5c, spreader
bars 14a and 14b are retracted into a collapsed position to draw
frame poles 10 and 12 together so that they are only separated by
the width of the collapsed spreader bars. Referring to FIGS. 5d-5f,
with hinges 20 in a lateral alignment, the frame arms can be
pivoted to draw them together to the folded configuration,
disengaging hinge supports 22 at the same time to allow movement of
the frame arms through the various illustrated folding stages.
[0040] Referring to FIGS. 4a-4c, advantageously, each of the frame
arms is constructed to include an interior cavity, designated
generally as 48, which is intended to remove as much material as
possible to make the frame arms light, while still maintaining the
durability and strength of the frame arms. Preferably, the interior
cavity runs the length of the frame arm. In order to remove as much
material as possible while maintaining the structural integrity of
the frame arms, at least one rib member 50 is molded into the frame
arm protruding from an interior surface of the frame arm into
interior cavity 48. As shown in FIGS. 4a and 4c, a plurality of rib
members 50 are spaced around the interior circumference of cavity
48 to provide the best strength to weight ratio. The rib member
preferably runs the length of the interior cavity to restrict
bending and twisting of the frame arm. Referring to FIGS. 4a and
4b, in addition to rib member 50, or independently, at least one
cross member 52 is molded into the frame arm extending through
interior cavity 48 from the interior surface of the frame arm.
Again, cross member 52 preferably runs the length of the interior
cavity to restrict bending and twisting of the frame arm.
[0041] While a preferred embodiment of the invention has been
described using specific terms, such description is for
illustrative purposes only, and it is to be understood that changes
and variations may be made without departing from the spirit or
scope of the following claims.
* * * * *