U.S. patent number 3,797,052 [Application Number 05/231,916] was granted by the patent office on 1974-03-19 for trendelenberg mechanism.
This patent grant is currently assigned to Simmons Company. Invention is credited to Charles Licina, Robert E. Miller, Nathaniel H. Taylor.
United States Patent |
3,797,052 |
Licina , et al. |
March 19, 1974 |
TRENDELENBERG MECHANISM
Abstract
A Trendelenberg mechanism for variable height beds of the kind
having legs telescopically extensible from and retractable into the
corner posts thereof by means of flexible cables extending from the
legs to a cable-hauling mechanism, in which the cables are
connected to the cable-hauling mechanism in pairs each respectively
associated with one of the ends of the bed, and in which one of the
cable pairs is disconnectible from the cable-hauling mechanism at
either of the fully raised or fully lowered positions of the bed
and retained at such position while the cable-hauling mechanism is
operated to lower or raise the other end of the bed, respectively,
thereby to tilt the bed longitudinally in either direction, i.e.,
to place the occupant in the "head-down" or Trendelenberg position,
or in the "head-up" or reverse Trendelenberg position.
Inventors: |
Licina; Charles (Thornton,
IL), Miller; Robert E. (Dyer, IN), Taylor; Nathaniel
H. (Highland, IN) |
Assignee: |
Simmons Company (New York,
NY)
|
Family
ID: |
22871137 |
Appl.
No.: |
05/231,916 |
Filed: |
March 6, 1972 |
Current U.S.
Class: |
5/607; 5/610 |
Current CPC
Class: |
A61G
7/005 (20130101) |
Current International
Class: |
A61G
7/005 (20060101); A61g 007/10 (); A47c
003/32 () |
Field of
Search: |
;5/60,62,63,64,86 |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
3206771 |
September 1965 |
Nordmark et al. |
3217339 |
November 1965 |
Black et al. |
3132351 |
May 1964 |
Huntress et al. |
|
Primary Examiner: Nunberg; Casmir A.
Attorney, Agent or Firm: Fitch, Even, Tabin &
Luedeka
Claims
What is claimed is:
1. In an elevating mechanism for a variable height bed having
extensible and retractable legs and flexible cables trained from
said legs to a common cable hauling mechanism on the frame of the
bed, a Trendelenberg adjustment which comprises the connection of
said cables to said cable - hauling mechanism by separate pairs
respectively associated with opposite ends of the bed, the
connection of one of said cable pairs being disengageable from the
cable-hauling mechanism at either the retracted or the extended
positions of the bed legs associated therewith, thereby to tilt the
bed longitudinally by subsequent extension or retraction
respectively of the legs associated with the other cable pair, and
means on the bed frame for carrying the load on said one cable pair
when disengaged from said cable-hauling mechanism.
2. The subject matter of claim 1 wherein the cable-hauling
mechanism comprises a screw-actuated draw bar, and the
disengageable cable pair is secured to a crosshead movable by said
draw bar in ways on said bed frame, and said load carrying means
includes the engagement of said crosshead with the bed frame at the
one end of said ways corresponding to the retracted position of the
associated bed legs, and detent means on said bed frame selectively
engageable with said crosshead at the other end of said ways to
maintain the extended position of said associated bed legs when the
draw bar is actuated to permit the retraction of the legs
associated with the other cable pair, and wherein the disengageable
connection of the draw bar and crosshead is a clutch normally
engaged to transmit the cable load on said crosshead to said draw
bar when said bed is elevated.
3. The subject matter of claim 2 wherein the selective engagement
of said detent means and the selective disengagement of said
normally engaged clutch are effected by a common manually operated
control.
4. The subject matter of claim 2 wherein the draw bar comprises in
part a rod passing freely through said crosshead and having thereon
a ball clutch positioned to engage the crosshead on one side
thereof to transmit the cable load to the draw bar, and wherein
said detent means comprises a normally disengaged hook member
movable on said bed frame to engage said crosshead to retain said
disengageable cable pair in full leg-extending position when the
draw bar is subsequently moved to permit the retraction of the legs
associated with the other cable pair.
5. The subject matter of claim 2 wherein the ways for the cross
head are defined by longitudinal slots in the webs of facing
channel members which flank and guard the draw bar, and the
crosshead has ends projecting sidewardly through said slots, and
said detent means comprises an upwardly open hook on the outside of
each channel member and connected to the other hook by an integral
cross member spanning the two hooks, each said hook pivoted to its
respective channel member on an axis common to both and raisable to
engage the sidewardly projecting ends of the crosshead by a
movement of the cross bar longitudinally of the bed, said clutch
being disengageable by a longitudinal control movement in the same
direction as the engaging movement of the integral cross member of
said hooks, and a common control for said clutch and hooks
comprising a rod running longitudinally of the bed from said clutch
and hooks to the foot of the bed and having means adapted to
disengage said clutch and to cause said hooks to engage the
projecting ends of said crosshead by movement of said rod in said
direction, said rod being movable longitudinally by a control
handle at the foot of the bed.
Description
This invention relates to hospital beds of the kind that are
variable in height, and particularly to a bed of that kind in which
the elevating mechanism can also be operated to tilt the entire bed
longitudinally to place the patient in a head - down or head-up
position.
The object of the invention is to provide in a cable - operated
elevating mechanism an inexpensive Trendelenberg adjustment by
means of which the cables attached to the four-telescopic legs of
the bed may be operated in unison to cause the bed to ascend or
descend uniformly, or may be operated selectively in pairs to
achieve the head-down, Trendelenberg or shock position, or
conversely, the head-up, reverse Trendelenberg, or drainage
position of the patient.
It is a more specific object of this invention to provide a cable
operated mechanism capable of achieving the aforementioned
positions by providing for the disconnection of the cables for one
end of the bed from a common cable-hauling drive unit when the bed
is either fully raised or fully lowered, and for the retention of
that one bed end in such position while the drive unit is operated
to lower or to raise, respectively, the opposite end of the
bed.
A further object of the invention is to provide a simple mechanical
device for securing the disconnected cable hauling mechanism
associated with the one bed end in the fully retracted position,
i.e., with the associated bed end fully raised, to insure against
inadvertent dropping of the raised bed end.
A still further object of the invention is to provide a simple
unitary control mechanism effective by the same control movement to
disconnect the drive unit from the aforementioned one bed end at
either the fully raised or fully lowered positions of the bed.
The invention will be better understood and the attainment of the
foregoing objects appreciated from the following description taken
in conjunction with the accompanying drawings in which:
FIG. 1 is a series of four cartoons showing the bed in side
elevation in its fully lowered, fully raised, head-down or
Trendelenberg, and head-up or reverse Trendelenberg positions;
FIG. 2 is a partial assembly view of the cable-operated elevating
mechanism with the portions of the bed not essential to the
elevating mechanism broken away to facilitate the orientation of
certain details within the overall assembly;
FIG. 3 is a fragmentary plan view of the cable hauling mechanism,
particularly of the mechanism for disconnecting one pair of cables
from the drive unit and for their retention at the position
corresponding to the fully-raised position of their associated bed
end;
FIG. 4 is a fragmentary side elevation corresponding to FIG. 3,
also partially broken away to emphasize certain details;
FIG. 5 is a fragmentary end elevation of the control mechanism for
the selective disconnection of the aforementioned disconnectable
cables;
FIG. 6 is a fragmentary enlargement of the cable disconnecting
mechanism shown at the left-hand end of FIG. 3; and
FIG. 7 is a corresponding side elevation of the same, showing the
two positions of the control mechanism by means of which the
aforementioned disconnectable pair of cables is separated from the
drive unit.
A quick summary of the mechanism and its operation may be had from
FIG. 2, which reveals that the drive unit comprises a screw 10
aligned with the longitudinal center line of the bed, and engaged
in a nut 12 at one end of a long draw bar assembly 14 axially
aligned with the screw. The head end of the bed is at the left of
FIG. 2, and the foot end at the right. The drive screw is located
at the foot end of the bed so that the motor and switch gear (not
shown), if the bed be electrically operated, are remote from the
area of oxygen administration, and so that the screw may be
conveniently turned by a crank at the foot of the bed, if operated
manually.
The draw bar assembly 14 comprises a pair of parallel metal straps
16 secured in flanking relation to the drive nut 12 at one end, and
at their other to a cross head 18 to which the cables 20 associated
with the foot end of the bed are attached. The draw bar assembly 14
continues toward the head of the bed as a single rod 22 of solid
circular cross section anchored in the crosshead 18 that draws the
foot end cables, and passing freely through a second crosshead 24
attached to the head end cables 26. Immediately headward of the
head end cross head 24, the draw bar 22 passes through a ball
clutch 28, the housing of which abuts the back side of the cross
head 24.
A control rod 30 at the foot end of the bed, when pulled upwardly
by a knob 32 at its upper end, is effective through a bell crank 34
to draw a longitudinal pull rod 36 toward the foot of the bed. The
extreme opposite or headward end of the rod 36 is curled about the
operating collar of the ball clutch 28, and when so moved when the
bed is in the fully lowered position illustrated in FIG. 2, serves
to disconnect the ball clutch 28 from the draw bar 22 and to permit
the draw bar 22 to pass freely through the head end cross head 24
leaving it behind, i.e., with the cables 26 of the head end fuly
extended and thus with the telescoped legs at the head end of the
bed fully retracted.
If power is applied to elevate the bed from its extreme low
position with the control knob 32 pulled up, only the foot end
cables 20 are hauled, the retractable legs to which they are
attached are thus extended from their corner posts, and the bed is
placed in position c of FIG. 1. When the drive screw 10 is
subsequently reversed, the foot end of the bed descends by gravity
as the draw bar assembly 14 moves toward the head of the bed, where
it becomes automatically recoupled with the ball clutch 28 that
backs up the crosshead 24 for the head end cables 26. If power be
again applied to elevate the bed, both cable crossheads 24 and 18
are drawn toward the foot of the bed, all cables retracted, all
legs thereby extended from their corner posts, and the bed may be
fully elevated to position b of FIG. 1.
With the bed in position b, and the control knob 32 once more
lifted, a double hook 38, pivoted on the bed frame, is positioned
to grasp the sideward guiding extensions of the head end cable
crosshead 24. When the power unit is operated, therefore, to send
the draw bar assembly 14 back toward the head of the bed, i.e., to
lower the bed, the head end crosshead 24 is securely retained in
the hook 38 to retain the head end of the bed in the nearly fully
raised position while the foot end descends. If descending motion
is continued to its limit, the bed achieves position d of FIG.
1.
The aforementioned operations are accomplished by mechanism now
described in detail by reference to FIGS. 3 to 7 inclusive in
association with the assembly of FIG. 2.
The structural underframing of the bed is suggested rather than
fully illustrated in FIG. 2, but may be readily visualized from the
illustration, together with the cartoons of FIG. 1, as comprising a
pair of facing channel rails 40 extending longitudinally of the bed
and spaced apart a distance considerably less than the overall
width of the bed. These side rails 40 are joined intermediate their
ends by a pair of cross rails 42 and 44, also of channel shape, and
are connected at their ends to the cross rails of the end frames 46
by means of suitable reinforcing gusset plates 48.
Each end frame comprises a pair of opposed corner posts 50
connected by the cross rail 46, of some depth, to which the
longitudinal side rails of the underframe are secured, and as
indicated in FIGS. 1 and 2, each corner post 50 houses a telescoped
retractable leg 52. The bed is raised by extending the retractable
legs 52 from the corner posts, and this in turn is accomplished by
the elevating cables 20 and 26, the far end of each of which is
staked by means of a swaged, offset fitting in a hole in the wall
of the extensible leg 52, which is preferably tubular.
The portions of each elevating cable 26 that is housed within a
corner post 50 passes downwardly between the outside of the
retractable leg and the inside of the hollow corner post, passes
around a sheave 54 and is directed to one of a pair of sheaves 56
in the cross rail of the end frame, from whence the cable 26
proceeds to its connection with the cable hauling crosshead 24.
The cables 20 for the foot end of the bed are rigged in much the
same manner, except that the pair of sheaves 58 at which the cables
depart the foot end of the bed are spread farther apart so as to
flank the driving motor and transmission, not shown. The foot end
cables extend toward the head of the bed passing through holes
provided in the cross member 44, and thence about the sheaves 60 in
the other cross member 42, reversing their direction to then extend
toward the foot of the bed, and being anchored in the fixed
crosshead 18 of the draw bar assembly. The foot end cables likewise
pass through clearance holes in the head end crosshead 24, which
may be disengaged from the draw bar assembly 14 for the execution
of the Trendelenberg position, as earlier explained.
As shown in FIG. 2, the spaced parallel straps 16 which at one end
flank the nut 12 engaged with the drive screw 10 extend through a
clearance hole in the web of the cross member 44 of the underframe,
and are welded at their opposite ends to a bar of square cross
section which serves as the cross head 18 for the foot end
elevating cables 20. At its mid-point, the crosshead 18 is drilled
and tapped (FIG. 6) to receive the threaded end of the draw bar 22,
which is circular in cross section, coaxial with the drive screw 10
along the center line of the bed, and extends through a suitable
slide bearing (not shown) in the cross member 42 between the two
return sheaves 60 of the foot end elevating cables 20.
As already indicated in the preliminary explanation, and as is
illustrated in FIGS. 2 and 6, the foot end elevating cables 20 are
anchored in the crosshead 18 and thus are permanently connected for
movement with the draw bar assembly 14. When the drive screw is
rotated to move the draw bar toward the foot of the bed, the foot
end cables 20 are retracted to extend the legs from the corner
posts of the foot end frame; conversely, when the screw is turned
in the reverse direction, moving the draw bar assembly 14 toward
the head of the bed, the foot end of the bed descends by its own
weight, retracting its legs, which in turn extends the cables.
The disengageable connection between the crosshead 24 for the head
end elevating cables 26 is more particularly shown in FIGS. 3, 4, 6
and 7.
It has already been said that the cable crosshead 24 is not fixed
in the draw bar assembly 14 but rather that the circular rod
portion 22 of the assembly passes freely through the crosshead 24,
a clearance hole 62 being provided for that purpose. Flanking the
central clearance hole for the draw bar rod 22 are the cable
anchores 64 for the head end cables, and flanking them in turn in
the cross bar are two additional clearance holes 66 to permit the
foot end cables 20 also to pass freely through the crosshead. In
its intermediate or midportion the cross head 24 is of square cross
section, but its projecting outer portions 68 are of circular cross
section, each milled to provide a flat upper quarter 70 facing the
head end of the bed for reasons later noted. The projecting outer
portions 68 of the crosshead 24 pass outwardly through guide slots
72 which are formed in the webs of a pair of facing channel members
74 and serve as ways for the crosshead 24. The channels 74 extend
longitudinally between the two cross members 42 and 44 of the
underframe of the bed, and serve as a housing and support for the
cable hauling mechanism.
Still referring to FIGS. 3 to 7 inclusive, there is mounted on the
rod portion 22 of the draw bar assembly 14, between the head end
cable crosshead 24 and the underframe cross member 42, the ball
clutch 28 which is normally connected to the rod portion 22 of the
draw bar assembly 14 for movement therewith, and which abuts the
head end cable crosshead 24 on one side. When the draw bar is moved
toward the foot of the bed, the ball clutch 28 after taking up a
slight clearance allowed for selective disengagement of the clutch,
bears against the back side of the cable cross head 24, likewise
moves the crosshead toward the foot of the bed, thus removing the
load from the ends of the guide slots 72, and hauling upon the head
end elevating cables 26 simultaneously with the hauling of the foot
end cables, and causing the bed to rise level. Similarly, when the
drive screw 10 is actuated to move the draw bar toward the head of
the bed, all cables likewise return in unison until the crosshead
24 re-engages the ends of the guide slots 72 in the webs of the
facing channels 74.
However, when the bed is in the fully lowered position, the ball
clutch 28 can be operated to disengage itself from the rod portion
22 of the draw bar assembly 14 to permit the draw bar assembly to
move freely toward the foot end of the bed, i.e., without hauling
upon the head end cable crosshead 24. The latter in that instance
maintains its fully lowered position determined by the abutment of
its outwardly extending portions 68 with the webs of the facing
channel rails at the ends of the slots 72, as indicated in FIG.
6.
The ball clutch 28 is actuated to free it from the rod portion 22
of the draw bar by a control knob 32 available for operation at the
foot of the bed. There, the vertical rod 30 is slideably mounted in
aligned holes in the cross member 76 of the foot end frame and a
U-shaped mounting bracket 78 which extends upwardly from the cross
member. These holes provide slide bearings for the rod 30 and may,
if desired, be provided with bushings of nylon or the like. The
bell crank 34 is pivoted on a pin 80 passing between the upstanding
legs of the U-shaped bracket 78.
The bell crank 34 passes through a slot 82 milled in the vertical
rod to which it is pivotally connected by means of a pin 84 passing
through and anchored in the vertical rod 30 and seated in a short
slot 86 in the bell crank. The other arm of the bell crank is
pivotally connected by means of a clevis 88 to the longitudinally
extending rod 36 which extends toward the head end of the bed.
At its opposite end, the long pull rod 36 is bent into a hook 90
(FIGS. 4 and 7) curled about and seated within a circumferential
groove 92 in the ball clutch actuator 94 through which the rod
portion 22 of the draw bar passes. The actuator 94 is cup-shaped on
its side facing the clutch proper, and the cup partially houses a
spring 96 which encircles the draw bar rod 22 between the actuator
94 and the clutch proper.
The ball clutch proper comprises an inner sleeve 98 having a free
slip fit on the draw bar rod 22, which passes through it. The
sleeve is provided with a plurality of radial holes, all in the
same plane and each forming a cage for a steel bearing ball 100
which provides the locking detent for the clutch. The rod portion
22 of the draw bar is suitably necked down to provide a seat 102 in
which to receive the detent balls in locking engagement, the seat
being chamfered at both sides to cam the balls radially outwardly
to disconnect the rod 22 from the inner sleeve 98 when outward
movement of the detent balls 100 is permitted.
Surrounding the inner sleeve 98 is an outer sleeve or cage 104
which has a slip fit with the inner sleeve 98 upon which it is
mounted. The interior of the outer sleeve is machined out from one
end to provide concentric cylindrical recesses 106 and 108 of
different diameters, the lesser 106 serving to confine the detent
balls 100 in the necked down portion 102 of the draw bar rod 22,
and the greater 108 movable into alignment with the detent balls by
the endwise movement of the clutch actuator 94, as illustrated in
FIG. 7, to permit the detent balls 100 to move outwardly, and thus
to release the draw bar rod 22 when the latter is drawn toward the
foot of the bed.
Between the outer sleeve 104 and a split ring 110 emplaced in a
groove cut in the outer surface of the inner sleeve 98 of the
clutch is a compression spring 112 which normally urges the outer
sleeve 104 into its ball-retaining position shown in FIG. 6. The
clutch disengaging movement, illustrated by broken lines in FIG. 7,
first takes up the clearance between the inner sleeve 98 and the
cross head 24 (FIG. 6), as the entire clutch assembly moves to the
right, and then compresses the spring 112 as the inner sleeve abuts
the crosshead 24 and the outer cage 104 continues to the right. The
spring 112 is maintained in the compressed condition as the detent
balls are forced outwardly in their cages in the inner sleeve 98 as
the outer cage 104 moves forward, pushed by the actuator 94. When
the draw bar rod 22 thereafter departs, the detent balls bear
against the full diameter portion of the draw bar rod and prevent
the outer cage 104 from returning. Therefore, when the draw bar rod
22 later returns to the position at which the disengagement was
made, the detent balls 100, urged by the camming engagement of the
step between the concentric cylindrical recesses 106 and 108 of the
outer sleeve 104,are returned into locking engagement with the
necked down portion 102 of the draw bar rod 22 as the compressed
clutch spring 112 returns the outer sleeve 104 to its retaining
position. As indicated in FIG. 6, the clutch assembly 28 moves
slightly to the left as the ball clutch re-engages the rod 22, thus
to provide the necessary clearance for the disengaging
movement.
The arrangement is such, therefore, as to require manual lifting of
the control knob 30 to disconnect the head end crosshead 24 from
the draw bar 22 but to permit the same to reconnect itself
automatically when the draw bar 22 returns to the fully lowered
position.
Also, it will be noted that when the draw bar assembly 14 moves to
the right as seen in all drawings, i.e., in a direction to elevate
the bed, both crossheads 24 and 18 move simultaneously if there has
been no manipulation of the Trendelenberg control at the extreme
low position. Once removed from the extreme low position, the ball
clutch actuator 94 is ineffective to disengage the ball clutch,
which, by the movement of the draw bar assembly to the right, or
footward, has moved out of the sphere of operation of the clutch
actuator, the inner sleeve 98 of the clutch pushing the cross head
24 before it.
In the foregoing manner, manipulation of the Trendelenberg control
knob 30 when the bed is raised from its extreme low position serves
to disable the head end cables 26, leaving the head end at the
extreme low position while the foot end is elevated. This condition
is indicated by the position c of FIG. 1.
By manipulation of the same control knob 30 when the bed is lowered
from its extreme high position, the bed may be placed in the
reverse Trendelenberg or drainage position shown in position d of
FIG. 1.
Referring again to FIG. 2, 3 and 4, it will be noted that the
facing channel rails 74 which house the cable hauling mechanism are
straddled by the double hook 38, which comprises a pair of upwardly
open hooks 114 united as an integral assembly by an upper cross bar
116 which passes over the top of the long control rod 36. The
double hook is pivoted on a pintle 118 which passes through aligned
holes in the hook portions 114 and in the facing channel rails 74,
and is maintained in assembly therewith by a cotter key which
prevents its withdrawal. The connecting cross bar 116 that units
the two hook portions 114 is notched, as shown particularly in
FIGS. 2 and 3 to form a seat for an upstanding stud 120 mounted on
the long control rod 36. The stud is drilled diametrically to
receive the control rod 36, and drilled and tapped axially to take
a set screw by means of which the stud is adjustably positioned on
the rod. Referring also to FIG. 4, it will be noted that the double
hook 38 is normally urged to the solid position of FIG. 4 by a
torsion spring 122 surrounding the pivot pintle 118 and having one
of its ends seated in a hole in the adjacent channel web and the
other bearing upon the double hook assembly.
The guide slots 72 in the webs of the facing channels 74, through
which the outwardly projecting ends 68 of the head end cable
crosshead 24 project, are sufficiently long, as is the normal
elevation stroke of the draw bar assembly 14, to bring the
outwardly projecting ends of the crosshead 24 into the operating
zone of the hooks 114. Thus, when the bed is at the fully elevated
position, and the Trendelenberg control knob 30 lifted, as before,
and the drive unit actuated to return the bed to the low position,
the double hook 38, having been moved by the stud 120 to the
intercepting broken line position of FIG. 4, serves as a detent to
retain the head end cable cross head 24 at the fully raised
position while the draw bar assembly, including the ball clutch 28
returns to the fully lowered position, thus placing the bed into
the attitude illustrated in position d of FIG. 1.
To insure against a mere casual or temporary engagement of the
double hook 38 with the sidewardly projecting ends 68 of the
crosshead 24, such as might result from lack of precise alignment
of the two hook portions 114 of the double hook, the flat 70 is
milled in the upper left-hand quarter of each end as viewed in FIG.
4 to provide an unstable center point of contact between the hook
point and the crosshead such that the crosshead 24 either seats
itself firmly within the hook, or it forces the hook 38 (and the
Trendelenberg control knob 30) downwardly. This precaution prevents
accidental dropping of the head end of the bed by either assuring
firm engagement with the hook or immediate notification of the
attendant of his abortive effort, and in any event, the safe
operation of the bed.
As in the case of the ball clutch 28, the double hook assembly 38
is likewise self-resetting when the cable hauling mechanism is
again returned to the position at which the cable crosshead 24 was
disconnected from the draw bar assembly. Specifically, upon return
movement of the draw bar assembly 14 to the fully raised position,
bringing with it the ball clutch 28, the inner sleeve 98 of the
ball clutch re-engages the back edge of the head end cable
crosshead 24, moving it slightly to the right from the broken line
position in FIG. 4, and freeing the ends 68 of the crosshead 24
from their seating engagement within the hook. With the cross head
thus moved slightly toward the foot of the bed from the broken line
position shown in FIG. 4, the double hook is returned to its
depending full line position of FIG. 4 by the action of the return
spring 122. The head end cable crosshead 24 thus remains supported
by the ball clutch 28 for its return to the fully lowered position,
absent further operation of the Trendelenberg control.
By providing a disengageable connection between one of the cable
hauling mechanisms and the drive unit together with a single
control mechanism operable to retain the disengaged cable hauling
mechanism at either its fully lowered or its fully raised position
while the cable hauling mechanism for the opposite end of the bed
continues its operation in the usual fashion, a simple and
relatively inexpensive and integrated mechanism is provided for
executing the Trendelenberg and the reverse Trendelenberg positions
in a hospital bed.
The features of the invention believed new and patentable are set
forth in the following claims.
* * * * *