Patient transport system

An apparatus secures at least two patient supports within a vehicle during transport, particularly adaptable within helicopters. Patient supports are secured to trays that are removably, telescopically connected to bases on a floor of a vehicle. The trays are telescopically, longitudinally, extended relative to the bases. Also, the trays are pivotally attached to a base for pivotal movement about an axis perpendicular to the floor, which includes an electric jack for moving the trays towards and away from the floor.

FIELD OF THE INVENTION 
The present invention generally relates to transferring and transporting 
patients in emergency medical vehicles, and more specifically relates to 
helicopters having interiors designed for quick, convenient, and safe 
transfer and transport of a plurality of patients and medical attendants. 
BACKGROUND OF THE INVENTION 
Aircraft, specifically helicopters, are commonly used to transport 
seriously injured patients to health care facilities. In order to use 
aircraft for medical purposes, the aircraft interior must be capable of 
accommodating the equipment and supplies necessary for proper care during 
transportation, in addition to one or more medical attendants who should 
have convenient access to the equipment, supplies, and, most importantly, 
the patient. 
Aircraft adaptable to medical missions can generally accommodate the weight 
of at least three passengers and up to as many as 32 passengers depending 
on the size of the aircraft. However, when one or more of the passengers 
is being transported in a prone position (as is generally necessary for 
medical purposes) the arrangement of the cabin interior affects the 
efficiency of treating the patient and the ability to accommodate a 
maximum patient load. If the interior is not properly configured, an 
aircraft readily capable of transporting two or more patients may be 
limited to a single patient. Hence, additional trips must be made with the 
aircraft, thereby increasing the expense in transporting two or more 
patients to a medical facility. Ultimately, the weight-carrying 
performance capability of the aircraft remains an unused resource. In 
addition, while the interior of some aircraft may be designed for two or 
more patients, inefficiencies in design of the interior can result in 
attendants preferring that only one patient be transported at a time due 
to inaccessibility to the patients when two or more patients are 
transported together, or wherein the equipment necessary to carry the 
second patient is so cumbersome to use that the attendants remove it from 
the aircraft, making it unavailable when needed. The culmination of 
inefficient medical vehicle interiors is a financial waste and a heavy 
burden on the medical facility sponsoring the vehicle, which is ultimately 
passed on to the patient and/or the patient's financial provider. 
No efficient method or apparatus is known for supporting a number of pieces 
of portable medical equipment in such a way that they are close to the 
patient, transportable with the patient and stretcher, and yet easily 
removed as a unit. 
In ambulances and other emergency/rescue vehicles such as helicopters, 
removable stretchers or patient litters are often provided for convenient 
and comfortable patient transfer and transportation. The litters for 
emergency medical aircraft use are somewhat standard, most using a Ferno 
#9 litter or the like. Such litters include a structural tubular frame to 
provide lightweight support for the patient. The litter includes wheels to 
support its head end and legs to support its foot end. Once the patient is 
carried or rolled on the litter to the helicopter, the litter is placed 
within the helicopter and fastened into position for safe transportation. 
When a stretcher or litter is placed within an emergency medical vehicle, 
it must be secured in place to prevent upset or injury not only to any 
patient who may be lying on the stretcher, but also to others nearby. 
However, for efficiency and safety, several other considerations exist 
beyond simply positively securing the litter within the vehicle. Any 
stretcher securing or locking system must be easy to use since time is 
often a critical factor and delays can be costly. The system should also 
be constructed to secure standard litters. Another consideration is space. 
The locking system should be small with a flat cross section, especially 
when not in use, to avoid catching on persons, objects, or portions of the 
litter. The locking system must also be clear of other tables or trays 
that may be used above or below the locking system. 
Frequently, more than one patient must be transported simultaneously. To be 
able to use the same vehicle, more than one station or table on which to 
secure stretchers or litters must be provided so that two or more can be 
safely and conveniently secured within one vehicle. However, space may be 
quite limited such that extra tables may be awkward to keep on board or 
hazardous in an emergency landing if the second litter is inadvertently 
left unsecured. Since an extra table must be kept clear while loading the 
first patient on the first litter or when loading only one patient and 
since adequate space may not exist to fold up and store an extra table 
when not in use, it may become cumbersome for the medical attendants to 
continually reposition the second litter. The attendants may choose not to 
use the second litter thus reducing the aircraft to a single patient 
aircraft. Therefore, a need exists for an apparatus including at least two 
litter tables or supports to secure litters while not interfering one with 
another. 
Considering the limitations and disadvantages of the devices and methods 
currently in use, it should be apparent that effective solutions to the 
problems of transferring and transporting patients in an emergency medical 
vehicle, such as a helicopter, including necessary equipment and supplies, 
and releasably securing a stretcher or litter within the vehicle are not 
provided in the known prior art. 
SUMMARY OF THE INVENTION 
The present invention provides a system for transferring patients to and 
from emergency medical vehicles and for securing the patients within the 
vehicles during transport. In the preferred embodiment, the system is 
adapted for aircraft, particularly helicopters, with at least two patient 
supports or stations within the helicopter for securing two patients 
therein. The system accommodates standard stretchers or patient litters, 
so that a patient need not be transferred from one type of cot or table to 
another, but can remain on the standard litter during the transfer and 
transport procedure. 
More specifically, in a preferred embodiment the aircraft interior is 
configured to have a first patient station in the rear of the aircraft 
approximately aligned with but above and behind a second patient station. 
The patients are loaded head forward such that the heads and chests of 
both patients are exposed for convenient access by an attendant or 
attendants. The patients are positioned toward one side of the aircraft, 
leaving room for attendants at the other. 
In order to load the patients into the separate stations, interlockable 
trays and support plates are used. An upper tray is initially telescoped 
within a lower tray and can be swung to an oblique position pointed toward 
the exterior door of a helicopter. The upper tray is adapted to receive 
the standard stretcher or patient litter thereon, and includes mechanism 
for locking the litter in position on the tray. Thereafter, the upper tray 
can be retracted into the lower tray, whereupon the assembly of telescoped 
trays can be swung inward to a position extending longitudinally of the 
aircraft. A lift assembly raises the interfitted trays such that the upper 
tray can be slid rearward into a bedplate assembly located in the aft 
portion of the aircraft cabin. The upper tray is separable from the lower 
tray after insertion into the bedplate. The lower tray is lowered by the 
lift assembly, and then is swung to the oblique position to receive a 
second patient litter through the exterior door. Finally, the second tray 
with the second patient litter secured thereon is swung to a 
longitudinally extending position along one side of the aircraft cabin. 
Preferably each tray has shallow grooves or tracks for the supporting posts 
and rollers of the standard stretcher or patient litter. At one end of the 
tray upright retainers are positioned to hook over the litter frame, 
whereas at the other end of the tray an axle locking assembly is provided 
including hooks for fitting over the axle of the litter. Identical locks 
are provided for both trays. 
Preferably the lower tray is mounted directly on a carriage and lift 
assembly. A releasable locking mechanism is provided to secure the lower 
tray in position extending longitudinally of the aircraft. When released, 
such locking mechanism permits the lower tray (and the upper tray if still 
supported thereon) to be swung toward the door opening at one side of the 
aircraft. The lift assembly also can be moved transversely of the 
aircraft, with locking mechanism being provided for securing the lift 
assembly in a desired transversely shifted position. 
In other aspects, the invention provides an apparatus for positioning and 
securing a patient support relative to an interior of a vehicle having a 
floor. The apparatus includes a first tray for removably receiving the 
patient support wherein the patient support can be secured to the first 
tray for transportation of a patient. The apparatus additionally includes 
a first base on the floor of the vehicle, with the first tray being 
removably, telescopically connected to the first base such that the first 
tray can be telescopically, longitudinally extended relative to the first 
base. Further, the first tray is pivotally attached to the first base for 
pivotal movement of the first tray about an axis generally perpendicular 
or orthogonal to the floor. Also, the first base includes a mechanism for 
moving the first tray towards, and away from, the floor. Preferably, the 
first base is movably secured to the floor of the vehicle. 
In further features of this apparatus, the first base includes a second 
tray in which the first tray detachably mounts such that the first tray 
and the second tray are removably, telescopically connected, allowing the 
first tray to be telescopically, longitudinally extended relative to the 
second tray. In this regard, the second tray is pivotally connected to the 
base to provide for the pivotal movement of the first tray and the second 
tray. 
In yet other aspects, the invention provides an apparatus for positioning 
and securing a first patient support and a second patient support relative 
to an interior of a vehicle having a floor. The apparatus includes a first 
tray for removably receiving the first patient support. The apparatus 
additionally includes a second tray for removably receiving the second 
patient support. Further, the first tray and the second tray are removably 
telescopically connected such that the first tray can be oriented on the 
second tray and can be telescopically, longitudinally extended relative to 
the second tray. This apparatus also includes a first base on the floor of 
the vehicle adapted to support the second tray. In this regard, the second 
tray is pivotally attached to the first base for pivotal movement of the 
first tray and the second tray about an axis generally perpendicular or 
orthogonal to the floor. Moreover, the first base includes an electric 
jack mechanism for moving the first tray and the second tray towards, and 
away from, the floor. Preferably, this apparatus has the first base 
movably secured to the floor of the vehicle. 
In further details of this apparatus, the first tray is removable from the 
second tray and is securable in the vehicle at a location remote from the 
second tray upon telescopic, longitudinal extension of the first tray 
relative to the second tray. This feature permits sequential loading of 
the first patient support onto the first tray followed by loading of the 
second patient support onto the second tray. 
In additional details of this apparatus, the first base and the second base 
each have a longitudinal axis, with the longitudinal axes of the first 
base and the second base being substantially parallel. Preferably, the 
longitudinal axes of the first base and the second base are also 
substantially coaxial when the electric jack mechanism has moved the first 
base a predetermined distance relative to the floor such that the first 
tray can be transferred from the first base to the second base.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
For purposes of describing the details of the preferred embodiment of the 
present invention, the preferred embodiment will be limited to an aircraft 
interior, specifically components of an interior for helicopters used for 
the transportation of injured patients. This includes both on-scene work, 
where the aircraft picks up the patient directly from the scene of an 
accident, and the transportation of patients from one location to another, 
such as from one medical center to a different medical center. 
The preferred aircraft interior configuration in accordance with the 
present invention is designed to accommodate one, two, or more patients on 
stretchers or litters with a minimum of one pilot and one medical 
attendant. It is the intent of the present invention to provide an 
interior which readily accommodates the transportation of two or more 
patients while functioning equally as well with one patient. 
The interior configuration described herein can be adjusted for different 
aircraft depending on accessibility to the aircraft interior through 
exterior doors, and the arrangement of the aircraft cabin. The patients 
could be located on the right side of the cabin, in which case the medical 
attendants would be located on the left side of the aircraft cabin, or 
vice versa. Also, the patients may be located substantially in the center 
of the aircraft with the attendants on either the right side or the left 
side of the aircraft or both. 
For purposes of further describing the present invention, the patients are 
loaded through the right side of the aircraft 21 and are positioned 
adjacent to the left side of the aircraft 21; the medical attendants are 
positioned toward the right side of the aircraft 21. This configuration 
corresponds to the layout of the cabin and exterior doors of a Bell 
222/230/430 helicopter. In this regard, the preferred positioning of the 
patients will be on the left side of the aircraft 21, the first patient 
being positioned substantially above, to the rear, and to the right of the 
second patient. The patients are loaded feet toward the rear of the 
aircraft so that the medical attendants have unrestricted access to the 
head and body torsos of each patient. The medical attendants of the 
present invention are located on the right side of the aircraft 21 and can 
move substantially from the forward bulkhead represented by the horizontal 
plane to the rear cabin bulkhead represented by the vertical plane. 
FIG. 1 illustrates the preferred positioning of two patient stretchers or 
litters as they would appear in a helicopter 21 having its cabin modified 
in accordance with the present invention. A first stretcher or littler L1 
is supported on the rear deck 55 which is positioned substantially above 
the aircraft floor 31 and higher than the second stretcher or littler L2. 
The litter L1 is offset toward the left of the aircraft for access by a 
medical attendant riding on the right, but not so far to the left as the 
lower litter L2. The rearwardmost position places the foot of stretcher or 
litter L1 close to the rear bulkhead 57 of the aircraft cabin. The head of 
the other litter L2 is positioned substantially forward of the head of 
litter L1, but still substantially to the rear of the pilot seat or seats. 
The litter L2 is supported above the aircraft floor 31 for convenient 
access by the medical attendant or attendants and to allow positioning of 
a carriage and lifting assembly 71 between the second litter L2 and the 
aircraft floor 31. 
With continued reference to FIG. 1, the upper stretcher or litter L1 is 
supported on an upper tray 61 which, in turn, is detachably mounted in a 
bedplate assembly 63, 64. The tray 61 includes a mechanism for locking the 
litter L1 in position on the tray 61. Similarly, bedplate assembly 63, 64 
includes a mechanism for locking the tray in such assembly (described in 
greater detail below). In addition, the front portion or front plate 63 of 
the bedplate assembly is pivotally mounted on the upper rear deck portion 
55 by hinges 65 for swinging about a horizontal axis extending 
transversely of the aircraft 21. Such axis is approximately aligned with 
the corner 56 at the leading edge of the rear deck portion 55. The rear 
portion or rear plate 64 is a channel iron permanently secured to the rear 
deck portion 55. 
The lower litter L2 is supported on and locked to a lower tray 67. The 
lower tray 67 is supported on the carriage and lift assembly 71. The 
carriage and lift assembly 71 allows the vertical position of the lower 
tray 67 and the litter L2 to be adjusted, even when carrying a patient. 
That is, the carriage and lift assembly 71 moves the lower tray 67 and the 
litter L2 towards, and away from, the floor. The carriage and lift 
assembly 71 also is movable transversely of the aircraft 21. Additionally, 
the lower tray is swingable relative to the carriage and lift assembly 71 
about a vertical axis located toward the foot end of the lower tray 67 and 
the litter L2. For example, FIG. 1 illustrates the lowered and leftmost 
shifted position of the carriage and lift assembly 71, as well as the 
longitudinally extending position of the lower tray 67. From such 
longitudinally extending position, the head end portion of the lower tray 
67 can be swung to the right, toward the exterior door opening 73 of the 
aircraft 21. Thus, the tray 67 is pivotally attached to the carriage and 
lift assembly 71 for pivotal movement of the tray about an axis generally 
vertical (i.e., perpendicular or orthogonal) to the floor of the vehicle. 
The final positioning of the patient litters L1 and L2 illustrated in FIG. 
1 provides convenient access to the patients by a medical attendant and/or 
attendants. In addition, the interconnection of the litter supporting 
trays 61 and 67 with the upper bedplate assembly 63, 64 and the carriage 
and lift assembly 71 permits quick, convenient and safe loading of a 
plurality of patients into the aircraft 21. 
The sequence of loading two patients is illustrated diagrammatically in 
FIGS. 2-7, in which some parts are deleted and, in general, parts are 
shown diagrammatically for ease in understanding the patient loading 
procedure. Also, in several views the patients and the litters on which 
they are supported are not illustrated so that the underlying components 
in accordance with the present invention can be seen. 
With reference to FIG. 2, initially the upper tray 61 is fitted within the 
lower tray 67, and the upper bedplate assembly 63, 64 is empty. There is a 
limited sliding fit of the upper tray 61 into the lower tray 67 such that, 
with the carriage and lift assembly 71 shifted toward the center of the 
aircraft 21 and with the lower tray 67 pivoted outward toward the exterior 
door opening 73, the upper tray 67 can be telescoped outward, preferably 
part way through the exterior door opening 73. It is not necessary to 
shift the carriage and lift assembly 71 toward the center of the aircraft 
21, however, this feature enhances loading and unloading patients. The 
first patient P1 supported on the standard stretcher or patient litter L1 
(such as a Ferno #9 litter) is loaded onto the upper tray 67. The litter 
L1 is slid rearward onto the upper tray 61, foot end first, until the 
litter L1 is fully supported on the upper tray 61. Then the litter L1 is 
locked in position (the locking mechanism being described in detail 
below). 
With reference to FIG. 3, the next step is to telescope the upper tray 61 
back along the lower tray 67 so that the two trays are substantially 
registered in the position shown in broken lines in FIG. 3. From such a 
position the lower tray 67 can be swung inward, back over the carriage and 
lift assembly 71 to the solid line position shown in FIG. 3. The 
telescoping action of the upper tray 61 over the lower tray 67 provides 
more convenient access for loading the patient through the exterior door 
opening 73, while permitting the lower tray 67 to remain in the retracted 
position so that once the upper tray 61 is locked into the retracted 
position on the lower tray 67, both trays 61 and 67 can be swung past the 
frame of the exterior door opening 73, inward to the solid line, 
longitudinally extending position. The carriage and lift assembly 71 and 
the trays 61 and 67, and the patient litter L1 supported thereby are 
shifted to the left of the aircraft 21, as indicated by the arrow 70, 
which can be done either before or after swinging the lower tray 67 to the 
longitudinally extending position. 
If only a single patient is to be transported, no additional steps are 
required to load and secure the patient in the aircraft 21. However, if a 
plurality of patients are to be transported, the carriage and lift 
assembly 71 is actuated to raise the lower tray 67, as well as the upper 
tray 61 and the patient litter L1 (and patient) supported thereby, to the 
position illustrated in FIG. 4. In the raised position of the carriage and 
lift assembly 71 illustrated in FIG. 4 and FIG. 5, the upper tray 61 is at 
approximately the same height as the bedplate assembly 63, 64 supported on 
the rear deck portion 55 of the aircraft 21. The upper tray 61 is released 
from the lower tray 67 such that it may be slid rearward into the bedplate 
assembly 63, 64 as illustrated in FIG. 5. In the rearwardmost shifted 
position of the upper tray 61, its foot end projects beyond the rear plate 
64, and a short section of the head end portion of the upper tray 61 
projects forward from the front plate 63 so as to overhang from the rear 
deck portion 55. The rearwardmost shifted position of the upper tray 61 is 
illustrated in solid lines in FIG. 6. 
As also illustrated in FIG. 6, the carriage and lift assembly 71 is then 
collapsed such that the lower tray 67 moves from the upper, broken line 
position to the lowered, solid line position. Then, the head end portion 
of the lower tray 67 is swung outward to the oblique position shown in 
FIG. 7, toward the exterior door opening 73. A second patient P2 supported 
on a litter L2 is loaded onto the lower tray 67 now exposed. If desired, 
the carriage and lift assembly 71 can be shifted transversely toward the 
center of the aircraft 21 to position the foot of the lower tray 67 nearer 
to the exterior door opening 73. Once the second patient litter L2 has 
been fitted onto the lower tray 67, the litter L2 is locked to the lower 
tray 67, and the lower tray 67 is swung inward to the longitudinally 
extending position shown in broken lines in FIG. 7. If the carriage and 
lift assembly 71 previously was shifted transversely toward the exterior 
door opening 73, it is shifted back to the leftmost position to provide 
more room for an attendant or attendants at the right side of the aircraft 
21. Both patients, particularly their heads and upper body torsos, are 
readily accessible to the attendant(s) during transportation to the 
destination facility. At such facility, the sequence of unloading of the 
patients is the reverse of the loading procedure described above. 
With reference to FIG. 8, prior to transport within a vehicle, such as a 
helicopter, the standard stretcher or patient litter L1 must be secured on 
its respective tray 61 or 67. The standard litter L1 includes a generally 
rectangular, peripheral frame 103 draped with a sheet 105 of canvas or 
similar material under tension on which the patient lies. Support posts 
107 extend downward near the foot end of the frame 103 on the right and 
left sides. Wheel brackets 109 extend downward near the head end on both 
sides of the frame. The axle 111 on which the wheels 113 are journaled 
extends crosswise between brackets 109. 
The trays 61 and 67 have identical components for releasably locking the 
standard litter in position. Each tray 61 and 67 includes a pair of 
shallow grooves or tracks 115 along its opposite longitudinal sides. The 
tracks 115 are open at the head ends 117 of the trays 61 and 67 such that 
the posts 107 can be easily inserted into the tracks 115 when the foot end 
of the litter L1 is first loaded onto the head end of a tray 61 or 67. 
Thereafter, the litter L1 can be slid rearward with the tracks 115 guiding 
rearward sliding movement of the posts 107. The raised edge portions of 
the tracks 115 limit transverse movement of the posts. The tracks 115 end 
near the foot end of the tray 61 or 67 where raised stops 119 prevent 
further rearward sliding movement. In the rearwardmost position of the 
litter L1 on the tray 61 or 67, posts 107 are engaged against stops 119, 
and wheels 113 are supported in the tracks 115 at the head end portion of 
the tray 61 or 67. 
As the litter L1 approaches its rearward position on the tray 61 or 67, the 
corners 121 of the litter frame 103 fit beneath inwardly curved upper end 
portions 123 of upright retainers 125. Such retainers 125 are positioned 
at opposite sides of the foot end portion of each tray 61 or 67, adjacent 
to the raised stops 119. The details of the mounting of the upright 
retainers 125 are shown in FIGS. 9 and 10. Preferably each retainer 125 is 
pivotally mounted on its tray 61 or 67 for swinging between a vertical 
litter-restraining position (shown in broken lines in FIG. 9) and an 
inwardly swung horizontal position (shown in solid lines) in which the 
retainer 125 is received in a recess 127 in the upper surface of the tray 
61 or 67. The recesses allow the retainers 125 to be folded down 
sufficiently so that they do not interfere with other components or catch 
on other objects. This is desirable, for example, with the retainers 125 
on the lower tray when the upper tray 61 is slid over the lower tray 67. 
As seen in FIG. 10, in the preferred embodiment the base portion 129 of 
each retainer 125 is fitted between short pivot blocks 131 and 133 mounted 
forward and rearward, respectively, of the retainers 125. A pivot pin 135 
has its opposite ends received in the pivot blocks and extends through the 
base portion 129 of the retainer 125 to achieve the desired pivotal 
mounting. In the raised, upright position of the retainer 125, illustrated 
in broken lines in FIG. 9, the outer side of the retainer 125 engages 
against an upstanding flange 137 along the adjacent side of the tray 61 or 
67. Such flange also defines the outer edge of the longitudinally 
extending tray groove or track 115. As seen in FIG. 10, a notch 139 can be 
provided in the forward side of the retainer 125, close to its base 
portion 129, for receiving the tip of a spring-loaded detent 141 carried 
in a horizontal bore 143 of the forward pivot block 131. Preferably notch 
139 is positioned to receive the detent 141 when the retainer 125 is in 
its upright position. When the retainer 125 is folded downward and inward, 
the detent 141 engages over the top of the retainer 125 to releasably 
maintain the retainer 125 horizontal. As seen in FIG. 9, the hooked end 
123 of the retainer projects sufficiently from the tray recess 127 to 
provide a fingerhold for swinging the retainer from the horizontal 
position to the vertical position against the action of the spring-loaded 
detent. 
With reference to FIG. 8, the retainers 125 in their upright positions 
snugly receive the foot end portion of the litter frame 103 at its 
opposite sides and prevent substantial vertical, transverse, or twisting 
motion of the litter L1 relative to the tray 61 or 67. At the head end of 
each tray 61 or 67, an axle lock assembly 145 is provided including hooks 
147 movable to a position for grasping the axle 111 to prevent substantial 
forward or upward shifting of the head end portion of the litter L1. Since 
rearward movement of the litter L1 is prevented by engagement of the posts 
107 against the stops 119, and vertical movement of the foot end of the 
litter L1 is prevented by the inwardly curved ends 123 of the retainers 
125 hooked over the litter frame 103, and transverse movement of the 
litter L1 is prevented at the foot end by the retainers 125 in combination 
with the posts 107 fitted in the tracks 115 and, at the head end of the 
tray 61 or 67, by wheels 113 snugly received in the tracks 115, the axle 
lock assembly 145 is the final component required to reliably secure the 
litter L1 to the tray 61 or 67. 
Referring to FIG. 11, the axle lock assembly 145 includes a generally 
rectangular frame plate 149, the swingable hooks 147, a handle 151 
pivotally mounted in the frame plate 149, and a linkage assembly 
connecting those components. The frame plate 149 is mounted in a recess 
(not shown) in the top of its respective tray 61 or 67 in the area below 
the litter axle 111 when the litter L1 is approximately centered over the 
tray 61 or 67. By manipulation of the handle 151, the hooks 147 are swung 
between an upright position in which the rearwardly curved upper ends 153 
of the hooks 147 are fitted over the axle 111 and a horizontal position in 
which the hooks 147 are retracted into the frame plate 149. The hooks 147 
rotate through an angle of approximately 90.degree. between the upright 
locking position and the horizontal retracted position. 
The linkage assembly by which the hooks 147, frame plate 149, and handle 
151 are interconnected includes a pair of generally horizontal arms 155 
joined by a transversely extending cross plate 157. The rear ends of the 
arms 155 project from the cross plate 157 and are pivoted to upright posts 
159 formed integrally with or secured to the frame plate 149. The front 
ends of the arms 155 are pivoted to the central portions of the hooks 147 
approximately midway between the top curved end portions 153 and the 
bottom portions of the hooks 147. 
As best seen in FIGS. 12, 13 and 14, the handle 151 is pivoted on the frame 
plate 149 by a horizontal transversely extending shaft 161. As seen in 
FIG. 12, the shaft 161 projects from the opposite sides of the handle 151 
through the adjacent section of the frame plate 149 and into cutouts 163 
where the opposite ends of the shaft 161 are fixed to inner links 165. 
Such links 165 extend in a forward direction from the shaft 161 when the 
axle hooks 147 are in their locking vertical positions, but rearward when 
the axle hooks 147 are retracted. The locked position is illustrated in 
FIGS. 11, 12 and 13. 
The ends of inner links 165 remote from the shaft 161, i.e., the swinging 
ends of the links, are pivotally connected to corresponding ends of outer 
links 167 by pivot pins 169. The opposite end portions of the outer links 
167 are pivotally connected to cross pins 171 projecting transversely from 
the lower end portions of the axle hooks 147. Cross pins 171 are guided 
for linear movement essentially fore and aft of the respective tray 61 or 
67 in elongated linear slots 173 formed in the frame plate 149. 
FIG. 16 illustrates the relative positions of the axle hooks 147, arms 155 
connected by the plate 157, handle shaft 161, inner rotating links 165, 
and outer sliding links 167. Links 165 and 167 and the bottom portions of 
the axle hooks 147 all are received within the cutouts 163 of the frame 
plate 149. 
Movement of the various components of the axle lock assembly 145 is 
illustrated in FIGS. 13, 14, and 15. With reference to FIG. 13, when the 
hooks 147 are in their vertical locking positions with the rearwardly 
curved upper ends 153 fitted over the litter axle 111, arms 155 are 
inclined forward and upward at a small acute angle relative to the frame 
plate 149 and the upper surface of the tray 61 or 67 in which the frame 
plate 149 is mounted. Handle 151 extends forward from its shaft 161 on 
which the inner rotating link 165 (not visible in FIG. 13 but seen in FIG. 
14) is carried. The outer sliding link 167 extends from pivot pin 169 
rearward to the cross pin 171 projecting from the bottom end portion of 
the hook 147. In the position illustrated in FIG. 13, i.e., the vertical 
locking position for the axle hook 147, the links 167 hold the cross pins 
171 in the forward end portions of the elongated slots 173. 
As seen in FIG. 14, in order to retract the axle hooks 147 to release the 
axle 111 of the litter L1, the handle 151 is rotated clockwise as viewed 
in FIGS. 13 and 21 about its shaft 161. The inner links 165 rotate with 
the handle 151 and thrust the outer links 167 rearward, thereby moving 
cross pins 171 rearward in the slots 173. Approximately 180.degree. 
rotation of the handle 151 is required in order to move the pins 171 to 
the rear end portion of the slots 173. Such motion rotates the axle hooks 
147 clockwise and retracts them into the frame plate 149 as the arms 155 
swing downward through a small angle toward the top of the frame plate 
149. The fully retracted position is illustrated in FIG. 15. 
As seen in FIG. 12, handle 151 can carry spring loaded detent fingers 175 
engageable in notches of the frame plate 149 to maintain the handle 151 in 
the locked position. Similar notches can be provided toward the central 
portion of the frame plate to hold the handle in the rearward swung, 
released position. 
The result is that the patient litter L1 can be quickly and easily inserted 
on and locked to a tray 61 or 67 during loading of a patient, and just as 
easily be released for unloading of the patient at the destination 
facility. 
Referring back to FIG. 8, after the patient litter L1 is locked in place on 
the upper tray 61, the upper tray can be retracted into the lower tray 67. 
If only one patient is being transported, the two trays 61 and 67 remain 
nested together. However, if more than one patient is to be transported 
within the same vehicle, it will be necessary to separate the upper and 
lower trays 61 and 67 respectively and, preferably, to position the upper 
tray 61 above and behind the lower tray 67. 
Several elements are included in both the upper and lower trays 61 and 67 
respectively to accomplish the proper nesting and separation of the trays 
61 and 67. FIGS. 17 and 18 illustrate the interconnection of the upper 
tray 61 with the lower tray 67, whereas FIG. 19 shows the upper tray 61 
separated from the lower tray 67, and FIG. 20 shows the lower tray 67 
separated from the upper tray 61. As best seen in FIG. 19, the upper tray 
61 includes a central rigid panel 179 having the recesses 127 for 
retainers 125 and a cutout for the axle lock assembly 145 including its 
frame plate 149. Inverted T slide strips 181 extend along the right and 
left sides of the tray panel 179. Each slide strip 181 includes an upright 
web portion 183 extending upward beyond short elongated edge blocks or 
strips 185. The strips 185 are notched to form the shallow tracks 115. The 
webs 183 border the outer sides of the tracks 115 of the upper tray 61. 
The slide strips 181 also include inward-extending arms 187 secured to the 
marginal portions of the underside of the tray panel 179 and 
outward-extending arms 189 projecting outward from the bottom of the 
vertical web 183. 
As best seen in FIGS. 18 and 20, the lower tray 67 includes a central panel 
191 having the recesses 127 (FIG. 20) for the associated litter retainers 
125 and a cutout for the axle lock assembly 145 including its frame plate 
149. These aspects of the lower tray 67 are identical to the corresponding 
parts of the upper tray 61. However, the panel 191 of the lower tray 67 is 
wider than the panel 179 of the upper tray 61, and the tracks 115 of the 
lower tray 67 (which must be spaced apart the same distance as the tracks 
for the upper tray 61) are fully formed in the long edge pieces 193 
secured to the upper longitudinal margins of the panel 191. Structural 
angular strips 195 extend along the opposite edges of the panel 191, 
including inward extending arms or flanges 197 secured to the bottom 
longitudinal margins of the panel 191 and the upward extending flanges 199 
that project above the tops of the edge pieces 193. The flanges 199 carry 
inward-projecting rails 201 which are spaced above the tops of the edge 
pieces 193 to form inwardly opening channels. 
As seen in FIG. 18, the channels between the edge pieces 193 and rails 201 
are sized to receive the outwardly projecting cross arms 189 of the 
inverted T slide strips 181. In addition, the webs 183 of such strips 181 
are in close proximity to the inner edges of the rails 201. The result is 
a sliding, interfitting connection of the upper tray 61 over the lower 
tray 67. 
As seen in FIG. 20, the lower tray 67 has a locking pin 203 extending 
inward through one of the flanges 199 at the head end portion of the lower 
tray 67. The shank of the pin 203 is positioned and sized to fit in holes 
205 and 207 (shown in FIG. 19) in the upright web portions 183 of the 
inverted T slide strip 181 at the same side. By fitting the locking pin 
203 in the hole 205 adjacent to the head end 117 of the upper tray 61, the 
upper tray 61 is locked in position substantially registered over the 
lower tray 67. In order to extend the upper tray 61 for loading of a 
patient, the locking pin is withdrawn, and the upper tray 61 is slid 
forward relative to the lower tray 67 until the pin 203 registers with the 
hole 207, whereupon the pin 203 is reinserted to lock the upper tray 61 in 
the forward or outward shifted position. 
When the upper tray 61 is transferred from the lower tray 67 to the 
deck-mounted bedplate assembly 63, 64, the interconnection of the upper 
tray with the bedplate assembly is substantially the same as the 
interconnection of the upper tray 61 with the lower tray 67. With 
reference to FIGS. 21 and 22, as previously described the front plate 63 
is connected to the upper deck 55 by hinges 65. The rear plate 64 is 
stationarily secured to the deck 55. Both portions have short edge strips 
209 secured to the top longitudinal margins of the bedplates 63, 64, and 
angular structural members 211 which correspond to the angular structure 
members (195) of the lower tray 67. Rails 213 are supported on the 
upward-extending flanges of structural members 211, spaced above the tops 
of the edge strips 209 to form channels 215 opening inward toward the 
center of the bedplates 63, 64. Also, the forward bedplate 63 includes a 
locking pin 217 corresponding to the locking pin 203 of the lower tray 67, 
including a shank 219 fittable into the holes 205 and 207 (FIG. 19) of the 
upper tray 61. 
FIG. 23 illustrates the upper tray 61 carrying the first patient litter L1 
being transferred from the lower tray 67 to the bedplates 63, 64. As seen 
in the sectional view of FIG. 24, the inverted T slide strips 181 rest on 
the edge strips 209 of the bedplate 63, 64, with the outward projecting 
cross arms 189 fitted in the channel between the rails 213 and the support 
strips 209, and the upright webs 183 close alongside the rails 213. When 
the transfer of the upper tray 61 onto the bedplate 63, 64 has been 
completed, such that the lower tray 67 is no longer interengaged with the 
upper tray 61, the lower tray 67 can be separated from the upper tray 61 
by collapsing the lift assembly 71 on which the lower tray 67 is mounted. 
The rear stationary bedplate 64 prevents the front bedplate 63 from 
swinging. Also, the locking pin 217 of the bedplate 63 can be used to 
secure the upper tray 61 in position interlocked with the bedplate 63, 64. 
As illustrated in FIG. 25, it is not necessary to move the upper tray 61 
all the way off of the lower tray 67 in order to disengage it from the 
lower tray 67. Preferably the rails 201 of the lower tray 67 are not 
continuous along each side, but rather have at least one space 221 at each 
side between adjacent strips of the rails 201. Similarly, the outward 
extending cross arms 189 of the upper tray 61 are not continuous but 
preferably have a notch 223 which, when the upper tray 61 has reached a 
predetermined position relative to the lower tray 67, is registered with 
one of the rail strips 201. The strips 201 and cross arms 189 are spaced 
to allow the trays 61 and 67 to be separated when the upper tray 61 still 
partially overlies the lower tray 67. 
The nesting of the upper tray 61 in the lower tray 67 allows both trays 61 
and 67 to be stowed together without taking up additional room for the 
second tray. Because of this arrangement, both trays 61 and 67 can be 
easily and conveniently left within the vehicle ready for use if needed 
without getting in the way or causing obstruction when not needed. 
The fit of the upper tray 61 in the lower tray 67 and in the bedplate 63, 
64 is quite snug. One advantage of the pivotal mounting of the front 
bedplate 63 on the upper rear deck 55 of the aircraft 21 is to allow for 
some variation in the position of the lower tray 67 supported by the 
carriage and lift assembly 71 when the transfer of the upper tray 61 to 
the front bedplate 63 is made. In addition, as illustrated 
diagrammatically in FIG. 26, such pivotal connection of the front bedplate 
63 to the upper rear deck 55 by hinges 65 permits an alternative carrying 
position for a single patient. It sometimes is desirable to maintain a 
traumatized patient at a slightly inclined angle, usually with his or her 
head below their feet. In accordance with the present invention, the upper 
tray 61 can be partially transferred into the front bedplate 63 and the 
locking pin 217 actuated to prevent further longitudinal adjustment of the 
position of the upper tray 61 to engage in a hole provided in the side of 
the upper tray 61 toward its foot end. Then the carriage and lift assembly 
71 can be partially collapsed to lower the lower tray 67, which will have 
the effect of tilting the upper tray 61. A latch 231 can be provided on 
the upper rear deck 55 adjacent to the bedplate 63 to prevent swinging of 
the bedplate and the upper tray 61 interlocked therewith beyond a 
predetermined angle. 
FIGS. 27 through 31 illustrate the preferred carriage and lift assembly 71 
in accordance with the present invention. Such assembly 71 includes a 
bottom rectangular frame 243 and a top rectangular frame 245. The top 
rectangular frame 245 carries a support plate 247 on which the lower tray 
67 is mounted. 
The frames 243 and 245 are interconnected by pairs of cross links 249 and 
251. The links 251 have their bottom end portions 253 pivoted to the 
bottom frame 243 toward its forward end. The links 249 have their forward 
end portions 255 pivoted to the upper frame 245 at its forward end. The 
links 249 and 251 are provided at both the left and right sides of the 
carriage and lift assembly 71. The links 249 and 251 at each side have 
their central portions connected by a pivot 257. 
The rear end portions of the links 249 and 251 carry rollers received in 
horizontal channels, namely, channels 259 carried by the bottom frame for 
receiving rollers projecting from the rear ends of the rearward and 
downward inclined links 249 and channels 261 secured to the top frame 245 
and receiving rollers projecting from the rear ends of the upward and 
rearward inclined links 251. 
The lift jack 263 for the carriage and lift assembly 71 is supported in the 
base frame 243 and includes an electric ram 265. Thus, the carriage and 
lift assembly includes an electric jack. The electric ram 265 is pivotally 
supported on the front portion of the base frame 243 and has a rearwardly 
extending spindle 267 pivotally connected to a cross member 269 (FIG. 28) 
extending between the lower, rearward end portions of links 249. For 
safety, the mechanical components of the carriage and lift assembly 71 are 
enclosed in a pleated bellows 273. 
The end portions of the cross links 249 and 251 define a parallelogram. The 
horizontal dimension of the parallelogram is directly controlled by the 
lift jack 263. Retraction of the spindle 267 of the lift jack decreases 
the horizontal extent of the parallelogram, thereby increasing the angle 
of inclination of the links 249 and 251 and raising the top rectangular 
frame 245 and the support plate 247 carried thereon. Similarly, extension 
of the spindle 677 of the lift jack 263 has the effect of decreasing the 
angle of inclination of the cross links 249 and 251 and lowering the 
support plate 247. 
The carriage and lift assembly 71 preferably is mounted in the aircraft 21 
for movement along conventional floor tracks 273 of a type commonly used 
in aircraft floors 31 for securing cargo or adjusting the position of 
passenger seats, for example. As seen in FIG. 28, such tracks 273 include 
a continuous central channel portion 275 and regularly spaced circular 
apertures 277. In accordance with the present invention, the carriage lift 
assembly 71 is supported in the tracks 273 on wheels 279, best seen in 
FIGS. 29 and 30. Such wheels 279 are mounted on the base frame 243 by 
wheel brackets 281. The wheels 279 are sufficiently narrow so as to roll 
in the continuous channel 275 (FIG. 28) of the floor tracks 273, for 
adjusting the position of the carriage and lift assembly 71 transversely 
of the aircraft 21. 
With reference to FIG. 29, movement of the carriage and lift assembly 71 in 
the tracks 273 is guided by legs 283 which depend from the base frame 243 
and have enlarged foot pads 285 fitted in the base of the tracks 273. In 
addition, the carriage and lift assembly 71 can be locked in a desired 
position by projection of thrust pins 287 into selected circular holes of 
the two tracks 273. Two such thrust pins 287 are provided, one for each 
track 273, and each thrust pin 287 is pivotally connected to the end of a 
generally upright actuating link 289. As seen in FIG. 27, the links 289 
are pivoted on brackets 291 mounted on the floor of the base frame 243 and 
have their upper end portions pivoted to the opposite end portions of a 
fore-and-aft extending link 293. A control lever 295 is accessible from 
the exterior of the base frame 243. Such lever 295 controls the position 
of the rearwardmost link 289 and, through the connecting rod 293, the 
position of the forward actuating link 289. Turning the lever 295 in one 
direction swings the links 289 so as to retract the thrust pins 287 and 
thereby free the carriage and lift assembly 71 for movement transversely 
of the aircraft 21 along the tracks 273; whereas turning the lever 295 in 
the other direction has the effect of projecting the thrust pins 287 
downward into the circular holes 277 of the tracks 273. The thrust pins 
287 are sized to be snugly received within the holes so that, when 
projected, the carriage and lift assembly 71 is locked in position and 
cannot be moved until the actuating lever 295 is turned. 
Again referring to FIG. 27, the top support plate 247 of the carriage and 
lift assembly 71 includes a rearward extending lip portion 301 having a 
pivot pin 303, which serves as the axis of rotation for the pivot 75, by 
means of which the lower tray 67 is connected to the support plate 247. 
The details of such connection are shown in FIG. 32. The top plate 247 of 
the carriage and lift assembly 71 has a circular hole 305 through which 
the pivot pin 303 extends. Such pivot pin 303 is formed integrally with a 
bottom disc 307 secured to the underside of the support plate 247. 
Similarly, the panel 191 of the lower tray 67 has an aperture for a socket 
member 309 formed integrally with a disc 311 secured to the upper side of 
the panel 191. An antifriction bearing 312 is interposed between the pivot 
pin 303 and the interior of the socket member 309. A retainer washer 313 
can be secured over the top of the pivot pin 303 to prevent separation of 
the panel 191 from the support plate 247 by blocking retraction of the 
bearing 312. 
FIG. 33 (bottom plan) illustrates the swinging motion of the lower tray 67 
permitted by the pivot pin 303. When the carriage and lift assembly 71 is 
collapsed, the head end of the tray 67 is supported on wheels 315. Such 
wheels 315 preferably are canted relative to each other. Each wheel 315 is 
mounted to the underside of the tray 67 for rotation about an axis which 
intersects the axis of the pivot pin 303. Consequently, the lower tray 67 
can be swung smoothly about the pivot pin 303. 
FIG. 34 illustrates the preferred mechanism for releasably locking the 
lower tray 67 in position extending longitudinally of the carriage and 
lift assembly 71. The lower tray 67 includes an I-beam 400 extending 
transversely below the panel 191 toward the forward or head end portion of 
the tray 67. The brackets 402 for the canted wheels 315 are secured to the 
underside of the I-beam 400. The top of the support top plate 247 of the 
carriage and lift assembly 71 has a cam member 404 that protrudes forward 
from the head end portion of the support plate 247 at its transverse 
center. The cam member 404 has a horizontal blind bore that opens through 
the forward end 406 of the cam member 404. 
A releasable locking mechanism includes a rectangular housing 408 mounted 
on a web 410 of the I-beam 400. The housing 408 encloses a central portion 
of a locking pin 412 that has a rear end portion 414 for fitting in the 
blind bore of the cam member 406. The pin 412 is biased to a rearward 
projected position by a compression spring 416. 
The rear portion 414 of the pin 412 protrudes from the rear of housing 408 
and is pivotally connected to a transversely extending leg 418 of a bell 
crank which has its central portion pivoted to mounting lugs or ears 420 
projecting rearward from the housing 408. The bell crank includes a 
forward projecting leg 422 that is pivotally connected to an actuating rod 
424. The rod 424 extends transversely beneath the head end portion of the 
lower tray 67, forward of the I-beam 400, and is pivotally connected to an 
actuating lever 426. The lever 426 is swingably mounted on the I-beam 400. 
In the position illustrated in FIG. 34, the rear portion 414 of the locking 
pin 412 bridges between the cam member 404 and the I-beam web 410. 
Consequently, the lower tray 67 is locked in a position extending 
longitudinally of the carriage and lift assembly 71. When it is desired to 
swing the head portion of the lower tray 67 outward relative to the 
carriage and lift assembly 71, the actuating lever 426 can be pulled such 
that, through the action of the bell crank 418, 422, the locking pin 412 
is retracted. When the lower tray 67 is swung back toward the 
longitudinally extending position, the rear portion 414 of the locking pin 
412 will engage the forward surface 406 of the cam member 404 and be 
wedged progressively inward against the force of the spring 416 until the 
locking pin 412 snaps into the bore of the cam member 404 and 
automatically locks the lower tray 67 in position. 
The close fit of the upper tray 61 over the lower tray 67 provides an 
important safety feature. When a litter L1 is first loaded onto the upper 
tray 61 and locked in position, the upper tray 61 is in its extended 
position, telescoped outward from the lower tray 67, as illustrated 
diagrammatically in FIG. 2. Thereafter the upper tray 61 is moved into a 
position registered over the lower tray 67. In such position, the close 
fit of the upper tray 61 over the lower tray 67 prevents the handle 51 of 
the axle lock assembly 145 mechanism from inadvertently being moved to the 
released position. Similarly, when the upper tray 61 is shifted onto the 
bedplate assembly 63, 64, preferably the handle 51 of the axle lock 
assembly 145 will fit over the front bedplate 63, so that the litter L1 
cannot be released without shifting the upper tray 61 forward, which would 
required that it be unlocked from the bedplate assembly 63, 64. Further, 
the handle 51 for the axle lock assembly 145 of the lower tray 67 fits 
closely over the support plate 247 of the carriage and lift assembly 71, 
which prevents inadvertent release of the second patient litter from the 
lower tray 67 when the lower tray 67 is in its longitudinally extending 
position. It is preferred that it be necessary to swing the lower tray 67 
relative to the carriage and lift assembly 71 in order to release the axle 
lock assembly 145. 
While preferred embodiments of the invention have been illustrated and 
described, it will be appreciated that various changes can be made thereto 
without departing from the spirit and scope of the invention. 
The embodiments of the invention in which an exclusive property or 
privilege is claimed are defined as follows: