U.S. patent number 3,900,906 [Application Number 05/461,959] was granted by the patent office on 1975-08-26 for adjustable bed.
This patent grant is currently assigned to Century Mfg. Co.. Invention is credited to Owen W. Berthelsen.
United States Patent |
3,900,906 |
Berthelsen |
August 26, 1975 |
Adjustable bed
Abstract
To adjust a bedstead to any angle with respect to the floor
without raising one edge to an excessive height, two corresponding
pairs of hydraulic cylinders of an adjustable bed are connected to
a movable frame along the pitch axis and roll axis of the movable
frame by universal joints to permit pivoting in any direction about
a stationary center point. As a first piston, connected at a
location along the roll axis, is extended, a corresponding second
piston, located a distance from the first piston along the same
axis, is retracted by an equal amount, so that the foot of the
bedstead moves in the opposite direction from the head of the
bedstead, with a point on the movable frame centered between the
two end connections of the piston rods rotating through an angle
but not moving vertically. Third and fourth hydraulic cylinders
operate in the same manner along the pitch axis to change the roll
position of the bedstead, with the roll axis and the pitch axis
having coincident midpoints.
Inventors: |
Berthelsen; Owen W. (Lincoln,
NB) |
Assignee: |
Century Mfg. Co. (Aurora,
NB)
|
Family
ID: |
23834637 |
Appl.
No.: |
05/461,959 |
Filed: |
April 18, 1974 |
Current U.S.
Class: |
5/608; 5/614 |
Current CPC
Class: |
A61G
7/002 (20130101) |
Current International
Class: |
A61G
7/002 (20060101); A61G 007/10 () |
Field of
Search: |
;5/61,62,66,81 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nunberg; Casmir A.
Attorney, Agent or Firm: Carney; Vincent L.
Claims
What is claimed is:
1. An adjustable patient support apparatus, comprising:
a base support;
said base support including a support member;
a movable frame adapted to support said patient in an adjustable
position having a first axis of rotation and a second axis of
rotation;
said first and second axes crossing substantially at a point of
intersection;
means for moving at least portions of said movable frame with
respect to said support member;
said means for moving said movable frame including means for
selectively pivoting said movable frame about the first axis of
rotation and about the second axis of rotation without
substantially changing the elevation of said point of intersection
with respect to said support member, whereby said movable frame is
pivoted in either or both of two directions;
said means for moving said movable frame including first movable
means for pivoting said movable frame about the first axis and
second movable means for pivoting said movable frame about the
second axis;
said first movable means including a first base mounted stationary
with respect to said support member and a first driven arm
connected to one point on one of said axes a first distance from
said point of intersection;
said second movable means including a second base mounted
stationary with respect to said support member and a second driven
arm connected to the other of said axes at a second point a second
distance from said point of intersection.
2. An adjustable patient support apparatus in accordance with claim
1 in which said base support further includes:
a universal joint; and
a stationary frame;
one portion of said support member being adapted to be supported on
said stationary frame and another portion being connected to said
point of intersection by said universal joint.
3. An adjustable patient support apparatus in accordance with claim
1 in which said first movable means further includes a third base
mounted stationary with respect to said support member and a third
driven arm connected to said one of said axes at a third point a
third distance from said point of intersection on the opposite side
of said point of intersection from said one point.
4. An adjustable patient support apparatus in accordance with claim
3 in which said second movable means includes a fourth base mounted
stationary with respect to said support member and a fourth driven
arm connected to said other of said axes at a fourth point a fourth
distance from said point of intersection on the opposite side of
said point of intersection from said second point.
5. An adjustable patient support apparatus in accordance with claim
3 in which said means for moving said movable frame includes means
for moving said first driven arm in a first direction a fifth
distance and said third driven arm a sixth distance in a second
direction with the product of said first and sixth distances being
equal to the product of said third and fifth distances, whereby
pivoting about said axis is provided.
6. An adjustable patient support apparatus in accordance with claim
4 in which said means for moving said movable frame includes:
means for moving said first driven arm in a first direction a fifth
distance and said second driven arm a sixth distance in a second
direction with the product of said first and sixth distances being
equal to the product of said third and fifth distances, whereby
pivoting about said one axis is provided; and
means for moving said second driven arm in a third direction a
seventh distance and said fourth driven arm an eighth distance in a
fourth direction with the product of said second and eighth
distances being equal to the product of said fourth and seventh
distances, whereby pivoting about said other axis is provided.
7. An adjustable patient support apparatus in accordance with claim
4 in which:
said first and second movable means includes first, second, third
and fourth hydraulic cylinders each having a different housing and
piston rod;
said first, second, third and fourth bases each comprising a hinge
means connecting the housings of said hydraulic cylinders to said
base support;
said first, second, third and fourth driven arms being the piston
rods of said cylinders.
8. An adjustable patient support apparatus according to claim 7 in
which said first and third distances are equal.
9. An adjustable patient support apparatus in accordance with claim
7 in which said base support further includes:
a universal joint; and
a stationary frame;
one end of said support member being adapted to be supported on
said stationary support frame and the other end being connected to
said point of intersection by said universal joint.
10. An adjustable patient support apparatus in accordance with
claim 9 in which said base support further includes means for
elevating said support member with respect to said stationary frame
whereby the elevation of said movable frame is changed.
11. An adjustable patient support apparatus in accordance with
claim 2 in which said universal joint includes needle bearings.
12. An adjustable patient support apparatus in accordance with
claim 2 in which said base support further includes means for
elevating said support member with respect to said stationary frame
whereby the elevation of said movable frame is changed.
13. An adjustable patient support apparatus in accordance with
claim 12 in which said bases and driven arms are lockable with
respect to each other.
14. An adjustable patient support apparatus in accordance with
claim 7 in which said first movable means includes:
a source of hydraulic pressure having first and second ports for
the application of pressure through one of said first and second
ports and the venting of hydraulic pressure through the other of
said first and second ports; and
first conduit means for selectively bringing one of said first and
second hydraulic cylinders into communication with one of said
ports and the other hydraulic cylinder into communication with said
other of said ports;
second conduit means for selectively bringing one of said second
and fourth hydraulic cylinders into communication with said second
hydraulic cylinder to one of said ports and said base of said
fourth hydraulic cylinder to the other of said ports.
Description
This invention relates to adjustable beds.
In one class of adjustable bed, the bedstead is adjustable in
attitude by changing the relative elevations of the head and foot
of the bed and in roll position by changing the relative elevations
of the two sides of the bed. This class of adjustable bed has an
advantage over other classes of adjustable beds in that the patient
may be positioned in a variety of different positions rather than
just in positions having different attitudes with his head lower or
higher than his feet.
In a prior art type of this class of adjustable bed, the bed
includes a first frame which remains parallel to the floor of the
room in which the bed is located and second and third frames, the
angles of which can be adjusted. The second frame is adjustably
mounted to the first frame and carries the third frame, with the
roll position of the second frame with respect to the first frame
being adjustable by a first mechanical linkage and the attitude or
pitch of the third frame being adjustable with respect to the
second frame by a second mechanical linkage to adjust the angle of
the bedstead in both roll and pitch positions.
The prior art type of adjustable bed has several disadvantages,
which are: (1) it is excessively expensive; (2) it is relatively
heavy because of the requirement of two separate movable frames and
one stationary frame; (3) it is relatively slow and clumsy to
adjust since the frames, for best results, must be adjusted one at
a time; (4) the adjustment in pitch direction raises an edge to an
undesirable height since the mechanism for pitch adjustment is
carried by the frame for roll adjustment and is therefore elevated
to some extent during the roll adjustment with the pitch adjustment
increasing the elevation further.
Accordingly, it is an object of this invention to provide a novel
adjustable bed.
It is a further object of the invention to provide an adjustable
bed which may be adjusted both in pitch and roll positions without
requiring that any edge be raised to an excessive height.
It is a still further object of the invention to provide a novel
adjustable bed which is adjustable both in pitch and roll positions
without placing strain upon the frame of the bed.
It is a still further object of the invention to provide a novel
adjustable bed in which the adjusting mechanisms need move only one
frame in either or both of two directions with respect to the base
of the bed to achieve the different positions desired.
It is a still further object of the invention to provide an
adjustable bed which is relatively simple to control.
It is a still further object of the invention to provide an
adjustable bed which may be supported at more than three points
with respect to a fixed base or floor.
It is a still further object of the invention to provide an
adjustable bed in which one side is moved upwardly as the other
side is moved downwardly about either or both a pitch axis or a
roll axis.
It is a still further object of the invention to provide an
adjustable frame for a bed which can receive and support different
designs of bedsteads such as for example, articulated bedsteads in
which the head or foot of the bedstead can be adjusted in position
with respect to the rest of the bedstead.
It is a still further object of the invention to provide a
hydraulically-controlled adjustable bed in which the possibility of
leakage of hydraulic fluid is remote, which can be locked in
position with relatively few valves and which remains locked even
though the hydraulic lines are opened.
In accordance with the above and further objects of the invention,
an adjustable bed, table or other apparatus used in hospitals to
change the position of a patient includes a base frame, a movable
frame and a tilting apparatus positioned between the stationary
base frame and the movable frame to position the movable frame with
respect to the base frame.
The base frame is mounted on rollers to move it to any location in
the hospital and remains stationary with respect to the floor once
in position. The movable frame supports a bedstead or a table upon
which the patient rests and is adjustable in attitude or roll
position with respect to the base frame to position the patient at
a selected angle for treatment. The bedstead may be any of a number
of differently designed bedsteads including some articulated
bedsteads in which the head and foot of the bedstead are
adjustable.
To adjust the position of the movable frame with respect to the
base frame, the tilting apparatus includes two pairs of hydraulic
cylinders with each hydraulic cylinder having its base connected to
the base frame of the adjustable bed. The distal end of each piston
rod of the hydraulic cylinders is connected to the movable frame
through a universal joint, with the piston rod ends of the first
pair of hydraulic cylinders being connected in a first line along
the movable frame to form a pitch axis about which the head and
foot of the bed rotate in an arc during pitch adjustment and the
piston rod ends of the second pair of hydraulic cylinders being
connected along a second line of the movable frame to form a roll
axis about which the sides of the bed rotate in an arc during roll
position adjustment, the pitch and roll axes being perpendicular to
each other and intersecting at their midpoints to form a stationary
point about which the head, foot and sides of the adjustable bed
rotate during adjustment.
The cylinders in each of the first and second pairs of cylinders
are double-acting cylinders with their ports connected through
valves to a source of hydraulic pressure so that fluid, when
adjusting the bed, is applied to one port of one of the cylinders
and to the opposite port of the other cylinder of a pair of
cylinders, forcing the one cylinder to extend its piston rod, while
the other cylinder retracts its piston rod or forcing the one
cylinder to retract its piston rod while the other cylinder extends
its piston rod, thus causing rotation in an arc about an axis of
the adjustable bed. Valves in the base of each of the cylinders can
be closed to lock the cylinders without danger of leakage and will
hold the cylinders in locked position even though the hydraulic
lines are open.
With this arrangement, the axes are independent of each other and
the pivoting of one axis in adjusting the pitch or roll position of
the bed does not affect the angle of the other axis even though the
other axis may be adjusted at the same time, thus permitting the
bed to be changed in pitch or roll position either simultaneously
or separately.
In the preferred embodiment, a center post has one end connected to
the center beam of the stationary base of the adjustable bed and
the other end connected to the point of intersection of the pitch
and roll axes of the movable frame through a universal joint to add
support to the frame.
From the above description, it can be understood that the
adjustable bed of this invention has the advantages of: (1) being
of relatively simple structure, requiring few parts and being
relatively economical to construct; (2) being adjustable in pitch
and in roll without requiring any side to be raised to an excessive
height; (3) being relatively easy to adjust in angle with an
uncomplicated automatic control; (5) being constructed so that
different designs of bedsteads can be mounted to the movable frame
of the adjustable bed; (6) being relatively free from leakage of
hydraulic fluid; (7) requiring relatively few valves; and (8)
remaining locked in position even if the hydraulic lines are
opened.
The above-noted and further features of the invention will be
better understood from the following detailed description when
considered with reference to the accompanying drawings, in
which:
FIG. 1 is a fragmentary, exploded, perspective view of an
adjustable bed in accordance with an embodiment of the
invention.
FIG. 2 is a schematic drawing of the hydraulic power system of an
adjustable bed in accordance with an embodiment of the
invention.
FIG. 3 is a fragmentary, exploded, perspective view of another
embodiment of adjustable bed in accordance with the invention.
FIG. 4 is a fragmentary, exploded, perspective view of still
another embodiment of adjustable bed in accordance with the
invention.
In FIG. 1, there is shown an exploded perspective fragmentary view
of an adjustable bed 10 having a bedstead 12, a movable supporting
frame 14, a frame pivoting section 16, a horizontal base frame 18,
and a control box 21, connected to each other in the order named
from top to bottom, with the control box 21 controlling the frame
pivoting section to adjust the movable supporting frame 14 and
bedstead 12 with respect to the horizontal base frame 18 at a
selected attitude and a selected roll position.
To support a patient, the bedstead 12 includes a base 20, a
headboard 22, and a footboard 24, adapted to support conventional
bedding such as a mattress 26 and a pillow 28. While a conventional
bed structure has been shown for the bedstead, other structures
such as tables and the like may be included instead and the
bedstead may include side rails or be free from side rails.
To support the bedstead or a patient table, the movable supporting
frame 14 includes an outer rectangular frame and an inner cruciform
frame, with the outer rectangular frame including first and second
longitudinally-extending parallel side beams 30 and 32 connected at
their ends by parallel transversely-extending end beams 34 and 36
to which they are welded. The two end beams 34 and 36 are formed of
square steel tubing and extend orthogonally to and between the ends
of the longitudinal side beams 30 and 32 which are steel
angles.
Within the rectangular outer frame, the cruciform inner frame
includes a longitudinal center beam 38 and a transverse center beam
40. The longitudinal center beam 38 is a square tubular steel beam
that extends parallel to and midway between the longitudinal side
beam 30 and 32 so as to lie along the roll axis of the movable
supporting frame 14, being welded at each of its ends to a
different one of the transverse end beams 34 and 36, and the
transverse center beam 40 is a square tubular steel beam that
extends parallel to and is midway between the transverse end beams
34 and 36 so as to lie along the pitch axis of the movable frame,
being welded to the longitudinal side beams 30 and 32 at its two
ends and intersecting the longitudinal center beam 38 at its
center, with the transverse center and longitudinal center beams 40
and 38 having a common midpoint to form the inner cruciform
frame.
The bottom sides of the cruciform frame are flush with the bottom
sides of the rectangular outer frame and the top sides are flush
with the transverse side beams 34 and 36 but, the longitudinal side
beams 30 and 32 are of greater height than the end beams and the
beams forming the cruciform inner frame to provide retaining sides
for the bedstead. Many different designs of bedsteads can be
mounted to the movable frame 14 including many types of articulated
bedsteads in which the head and foot are adjustable in angle with
respect to the center portion of the bedstead.
To enable the movable supporting frame 14 to be mounted to the
frame pivoting section 16, the cruciform inner section has welded
or fastened by other means to its bottom side a universal joint 64
at the junction 37 of the longitudinal center beam 38 and
transverse center beam 40. The longitudinal beam 38 has, fastened
to its bottom surface, a first universal joint 41 between the
junction 37 and the side transverse beam 34 and a second universal
joint 42 spaced between the junction 37 and the transverse beam 36
for mounting piston rods of the frame pivoting section 16.
Similarly, the center transverse beam 40 has first and second
universal joints, one being shown at 44, each being spaced between
a different one of the side longitudinal beams 30 and 32 and the
center junction 37.
To support the adjustable bed, the horizontal base frame 18
includes first and second longitudinally-extending steel beams 48
and 50 connected in parallel relationship to each other by five
transverse beams 52, 54, 55, 56 and 57, with each of the transverse
beams being parallel to each other and being welded at its opposite
ends to different ones of the two longitudinally-extending beams 48
and 50. To permit the bed 10 to be moved from position to position,
four casters 58A-58D are mounted to the longitudinally-extending
beams 48 and 50, with a different caster being mounted to each
different end of the beams.
To pivotally support the movable supporting frame 14 with respect
to the base frame 18, the frame pivoting section 16 includes a
center post 60 mounted firmly by a bracket 62 at its bottom end to
the center of the center transverse beam 54 and having the
universal joint 64 at its upper end for connection to the movable
supporting frame 14 at the junction 37.
The universal joint 64 includes a top yoke 86 that is fastened at
the junction 37 of the beams 38 and 40 and a bottom yoke 87
connected to the top of the post 60, with the first yoke 86 being
rotatably connected to the second yoke 87 by a needle bearing
spider to permit the movable supporting frame 14 to move in the
roll or pitch directions about the post 60. This type of universal
joint is a type commonly used in automobiles and provides very
little free play, permitting only motion in the rotational
directions along the needle bearings so that the frame 14 has
substantially no lateral motion and provides tilting motion.
To support the center post 60, four tubular struts 66A-66D are each
fastened at one of its ends to the top portion of the post 60 near
the universal joint 64 and at its other end to a different location
on the base frame 18 to form a rigid pyramidal supporting structure
about the center post 60. Each of the lower ends of the struts 66
is fastened to a different intersection of one of the
longitudinally extending beams 48 and 50 and the
transversely-extending beams 52 and 57.
To tilt the movable mattress supporting frame 14 and hold it in a
selected position, the frame pivoting section 16 includes four
hydraulic cylinders 68A-68D, each having one end pivotally
connected to a central portion of the transverse beam 54 at the
base of the post 60 with its piston rod positioned to extend
outwardly and upwardly therefrom and connected to a different one
of the four universal joints on the center cruciform frame of the
movable supporting frame 14 (three of the universal joints 41, 42
and 44 being shown in FIG. 1).
With this arrangement, two of the hydraulic cylinders 68A and 68C
have their piston rods connected to two different positions along
the longitudinal center beam 38 equal distances from the universal
joint 64 and two others of the hydraulic cylinders 68B and 68D have
piston rods connected to the center transverse beam 40 equal
distances from the universal joint 64 so that: (1) to change the
attitude of the movable supporting frame 14, one of the piston rods
in one of the hydraulic cylinders 68A or 68C is extended and the
piston rod in the other of these two hydraulic cylinders is
retracted by the same distance that the first one is extended; and
(2) to change the roll position of the movable supporting frame 14,
the piston rod in one of the hydraulic cylinders 68B and 68D is
extended and the piston rod in the other of these two cylinders is
retracted an equal amount.
Because the hydraulic cylinders 68A and 68C that adjust the movable
frame 14 in pitch have their piston rods connected to the movable
frame along the roll axis, it is not necessary for them to change
their amount of extension as the roll position of the movable frame
is changed. Similarly, the hydraulic cylinders 68B and 68D do not
have to change their amount of extension as the pitch is changed
since their rods are connected along the pitch axis. Moreover, each
pair of cylinders can independently change the angle of the movable
frame along its own axis, either at the same time or at a different
time from the time the other pair is changing the angle of the
movable frame along its axis.
To provide power to the hydraulic cylinders 68A-68D, a hydraulic
pump assembly 70 is mounted to a plate 72 which is mounted to the
two transverse beams 55 and 56, with the hydraulic pump assembly 70
supplying fluid through valves under the control of the control box
21.
The control box 21 includes switches actuated from its front panel
through push buttons 74, 76, 78 and 80, to control the hydraulic
pump assembly 70 and open and close the solenoid valves that change
the attitude and roll positions of the movable frame 14 or lock in
position and unlock the movable frame in a manner described more
completely hereinafter with respect to FIG. 2.
More specifically, these push buttons are connected so that: (1) to
raise the headboard 22 of the bedstead 12, the push button 74 is
depressed; (2) to lower the headboard, the push button 76 is
depressed; (3) to lower the right side of the bedstead, the push
button 78 is depressed; and (4) to raise the right side of the
bedstead, the push button 80 is depressed. With these connections,
one of the two buttons 74 and 76 can be depressed at the same time
as one of the two buttons 78 and 80 to change the attitude and roll
positions of the bedstead simultaneously.
In FIG. 2, there is shown a schematic diagram of a hydraulic system
100, having its hydraulic pump assembly 70, the four hydraulic
cylinders 68A-68D, and eight solenoid-controlled valves 102A-102D
and 104A-104D.
To provide fluid pressure for the operation of the hydraulic
cylinders 68A-68D, the hydraulic pump assembly 70 includes an
electrically-driven reversible motor 108 and a hydraulic pump 110,
having hydraulic lines 114 and 116, with the direction of the motor
determining the direction of flow of the fluid through the
hydraulic lines 114 and 116.
To pivot the mattress supporting frame 14, the hydraulic cylinders
68A-68D are double-acting hydraulic cylinders, each with a
corresponding one of the normally-closed solenoidcontrolled valves
104A-104D within and communicating with its base to form a
controllable piston-rod extending port.
To permit fluid to flow into and from the hydraulic cylinders while
the bed is being adjusted, the pump 110 communicates with: (1) the
valve 104A and piston rod retracting port of hydraulic cylinder 68C
through line 116 and the normallyclosed, solenoid-controlled valve
102C; (2) the valve 104C and the piston rod retracting port of
hydraulic cylinder 68A through line 114 and the normally-closed
solenoid-controlled valve 102A; (3) the valve 104B and the piston
rod retracting port of hydraulic cylinder 68D through line 116 and
the normally-closed, solenoid-controlled valve 102D; and (4) the
valve 104D and the piston rod retracting port of hydraulic cylinder
68B through the normally-closed line 114 and solenoid-operated
valve 102B.
Each pair of piston rod retracting ports and valves 104 are
connected to the appropriate hydraulic line through different
branches of a T-connector so that, as the piston rod of one of the
hydraulic cylinders 68A and 68B moves in one direction, the piston
rod of the respective hydraulic cylinder 68C and 68D is moved in
the opposite direction by the hydraulic fluid.
With these connections, when one of the four sides of the
supporting frame 14 is raised by one hydraulic cylinder, the
opposite side is lowered by the other hydraulic cylinder of the
pair of hydraulic cylinders along one of the two axes to pivot the
frame about the other of the two axes, with the piston rods of the
other pair of cylinders being connected along the other axis. Since
the pivoting of one axis does not change the elevation of any part
of the other axis, either pair of hydraulic cylinders can pivot the
frame 14 about one axis or both can pivot the frame 14 about their
respective axis.
To extend and retract the pistons in a corresponding pair of the
hydraulic cylinders 68A-68D, the normally-closed solenoidoperated
valves 102A-102C and 104A-104D that communicate with that pair of
the hydraulic cylinders are opened and the pump 110 is driven by
the reversible motor 108 in a direction to force fluid into the
piston rod extending port of the hydraulic cylinder that is to
raise one end of the bedstead and to receive fluid from the
hydraulic cylinder that is to lower one end of the bedstead.
In FIG. 2, the hydraulic cylinders are shown in the position they
have when adjusting the supporting frame 14 (FIG. 1) in both
attitude and roll (all valves open) and being temporarily in a
position where the foot of the bed is downward, its head is upward
and there is no roll position with the valves being ready to move
the bed out of this position. This is shown by the hydraulic
cylinder 68A having its pistion completely retracted to the lowest
position and the hydraulic cylinder 68C having its pistion fully
extended to the highest position. The hydraulic cylinders 68B and
68D, which control the roll position of the bed, have their pistons
positioned intermediately in the cylinder so as to position the bed
in its neutral roll position.
While a hydraulic system is disclosed in the preferred embodiment,
other moving systems, such as electrically driven screws, can be
used instead. Moreover, it is possible to omit the valves 102
entirely in the embodiment of FIG. 2 since the valves 104 each lock
one cylinder against one direction of motion and the pairs of
cylinders work against each other so that each pair of valves
controls one of the directions of motion. However, if one of each
of the cylinders in each of the pairs of cylinders is omitted, then
the valves 102 must be included, but since there are only two
cylinders in such an embodiment, only four valves 102 are
required.
There is less danger of leakage if the valves 102 are omitted from
the embodiment of FIG. 2 since external valves are subject to
leakage and the valves 104 are inside the cylinders. Moreover, if
the hydraulic lines are opened, the cylinders remain locked since
they are held by fluid trapped between the pistons and the closed
valves 104 in an embodiment having four cylinders and not including
the valves 102.
In FIG. 3, there is shown a portion of another embodiment of an
adjustable bed 134 similar to the adjustable bed 10, differing in
that the hydraulic cylinders are mounted substantially vertically
to the transverse beams 52, 54 and 57. In FIG. 3, parts of the
adjustable bed 134 are the same and are numbered the same as parts
of the adjustable bed 10 in FIG. 1, and other parts, not necessary
to explain in this embodiment, are omitted from FIG. 3
altogether.
In the embodiment of FIG. 3, the hydraulic cylinders 68A and 68C
are mounted substantially vertically to the center of the parallel
cross beams 52 and 57 and the hydraulic cylinders 68B and 68D are
mounted substantially vertically to opposite ends of the cross beam
54, which is parallel and centered between the cross beams 52 and
57, so that an imaginary roll axis, shown by the dotted line A-C,
and an imaginery pitch axis, shown by the dotted line D-E, pass
through the ends of the piston rods of the hydraulic cylinders,
intersecting each other orthogonally near the center of the movable
supporting frame 14.
The hydraulic cylinders 68A-68D are connected for operation in the
manner shown in FIG. 2 which is identical to the connection used to
extend and retract the pistons of the hydraulic cylinders in the
embodiment of FIG. 1. With these connections, the attitude of the
movable supporting frame 14 is changed by pivoting the frame 14
about the pitch axis D-B without requiring a change in the vertical
or horizontal position of the piston rods of the hydraulic
cylinders 68D and 68B as the attitude of the movable frame 14
changes. Similarly, when the roll position of the supporting frame
14 is changed, the roll axis A-C rotates but does not move
vertically or horizontally as the pitch axis D-E pivots its end
points.
The pistons are locked as shown and explained in connection with
FIG. 2 once a desired position is obtained. Both attitude and roll
position of the frame 14 can be changed simultaneously, in which
case, the intersecting point of the axes A-C and D-E remains fixed
except for rotating while the end points of the roll and pitch axis
move horizontally as the movable supporting frame 14 changes
attitude and roll positions.
Prior to operating the adjustable beds 10 or 134, a patient on the
bedstead 12 can be moved to any location by rolling the adjustable
bed to that particular location. For example, the patient can be
placed on the adjustable bed in a hospital ward and moved to a
treatment room.
In operating the adjustable bed, the position of the patient can be
adjusted by changing the attitude, the roll, or both the attitude
and the roll positions of the movable supporting frame 14. This is
accomplished through the control box 21 (FIG. 1) which controls the
pivoting section 16 to tilt the bedstead 20 (FIG. 1) into any
selected position.
To change the attitude of the movable supporting frame 14 so that
the head of the bed is lower than the foot of the bed, the push
button 76 (FIG. 1) on the control box 21 is depressed, causing the
motor 108 to rotate (FIG. 2) to operate the pump 110 and opening
valves 102A and 104C to force fluid through line 116, valve 102A,
into the hydraulic cylinder 68A, valve 104C of cylinder 68C and
from the valve 104C into the cylinder 68C, with fluid returning to
the pump 110 through valve 102C and line 116 so that the piston rod
of the hydraulic cylinder 68C is extended, thus causing the bed to
pivot about the beam 40.
Similarly, to lower the foot 24 with respect to the head 22 of the
bed, the push button 74 on the control box 21 is depressed to cause
the motor to operate in the reverse direction and to open valves
102A and 102C in which case the pump 110 forces fluid through line
116 and valve 102A to move the piston rods in the opposite
directions with the fluid returning to the pump through valve 102C
and line 116, thus extending the piston rod in the cylinder 68A and
retracting the piston rod in the cylinder 68C.
To adjust the roll position of the bed by pivoting about the roll
axis while resting on the universal joint 64, the push button 78 is
depressed to lower the right side and the push button 80 is
depressed to lower the left side of the supporting frame 14.
Depressing the push button 78 causes fluid to be pumped through
line 114 and valve 102B to the hydraulic cylinder 68B and to the
valve 104D from which it enters the hydraulic cylinder 68D, thus
extending the piston rod in the cylinder 68D and retracting the
piston rod in the cylinder 68B to cause the right side of the bed
to lower. Depressing the push button 80 causes fluid to flow in the
other direction by reversing the motor 108 and opening the same
valves to pivot the bed in the opposite direction.
When none of the push buttons 74, 76, 78 or 80 are depressed,
valves 102A-102D and 104A-104D are closed and the pistons firmly
locked in position to prevent further motion. With this
mechanization, the bed is held firmly from motion except when its
position is being changed. Of course, both the pitch and the roll
positions may be changed simultaneously if desired.
If FIG. 4, there is shown a portion of another embodiment of
adjustable bed 140 which is similar to the adjustable bed 10 shown
in FIG. 1 except for the frame pivoting section 16. Parts of the
embodiment of FIG. 4 that are identical to parts of the embodiment
of FIG. 1 have the same reference numerals.
As shown in FIG. 4, the frame pivoting section 16 includes two
upstanding bearing supports 142 and 144 each mounted to the center
of a different one of the two longitudinally-extending beams 48 and
50 in the base frame 18. To permit changes in pitch of the bed, an
elongated rod 146 serving as a center bearing is mounted on the two
supports 142 and 144, thus lying parallel midway between the two
end beams 52 and 57, with an outer tubular pitch axle 148 being
positioned for rotation upon the elongated bearing 146. To permit
adjustment in the roll position of the frame 14, an outer
cylindrical tubular bearing 150 is welded orthogonally to the pitch
axle 148 and extends along the longitudinal axis of the adjustable
bed 140 midway between the two longitudinally-extending beams 48
and 50. An inner roll axle 152 fits within the tubular bearing 150,
with each of two bed frame supports 154 and 156 being welded to a
different end of the roll axle for movement therewith.
To change the attitude or pitch of the bed, the hydraulic cylinder
158 has its base mounted to the end transverse support 57 and its
piston rod 160 mounted by a lever to the tubular pitch axle 148 to
rotate the pitch axle as the piston rod 160 is extended or
retracted. To change the roll position of the bed, a second
hydraulic cylinder 162 has its piston rod mounted by a lever to the
roll axle 150 and its base to the tubular bearing 150 by another
lever to pivot the roll axle 150 with respect to the bearing 162
and thus change the roll position of the bedstead.
The hydraulic cylinders can be locked and controlled in a manner
directly analogous to the manner in which the hydraulic cylinders
of the embodiments of FIGS. 1 and 3 are controlled and locked,
except that only two cylinders cooperate with four valves to
control the roll positions and the pitch positions instead of four
cylinders and four or eight valves.
In the embodiments of FIGS. 1 and 3, two pairs of cylinders are
included, with the two cylinders in each pair having equal strokes.
However, it is possible to use two cylinders only or to space the
cylinders at different distances from the intersection of the axis
and compensate for the differences in this distance by including
cylinders having different strokes. Moreover, the stationary point
at the intersection of the pitch and roll axes need not be centered
on the bed although this provides the lowest maximum elevation of
an edge of the bed for each angle. It is also possible to mount the
frame pivoting section 16 to a movable support member that can be
altered in elevation with respect to the base frame 18 so that the
base support for the movable frame 14 is the movable support member
rather than the base frame 18 to permit changes in elevation of the
entire movable frame.
From the above description, it can be understood that the
adjustable bed of this invention had the advantages of: (1) being
of relatively simple structure, requiring few parts and being
relatively economical to construct; (2) being adjustable in pitch
and in roll without requiring any side to be raised to an excessive
height; (3) being relatively easy to adjust in angle with an
uncomplicated automatic control; (5) being constructed so that
different designs of bedsteads can be mounted to the movable frame
of the adjustable bed; (6) being relatively free from leakage of
hydraulic fluid; (7) requiring relatively few valves; and (8)
remaining locked in position even if the hydraulic lines are
opened.
Although a preferred embodiment has been described with some
particularity, many modifications and variations of the preferred
embodiment may be made without deviating from the invention. It is
therefore to be understood that, within the scope of the appended,
the invention may be practiced other than as specifically
described.
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