Abstrict An adjustable bed carriage for supporting a main bed frame above
a substantially planar floor. The adjustable bed carriage has a
first leg with an upper end slidably attached to a first end of
the main bed frame and a second leg with an upper end pivotably
attached to a second end of the main bed frame. Each of the first
leg and the second leg are pivotably connected to each other at
a central pivot located substantially at a midpoint of each, to
permit pivoting movement of each of the first leg and the second
leg about the central pivot in opposite directions. The pivoting
movement of the legs moves the adjustable bed carriage between a
fully extended condition and a fully collapsed condition.
Claims We claim:
1. An adjustable bed for use on a substantially planar floor, the
adjustable bed including: a main bed frame having a first end and
a second end; an adjustable bed carriage for supporting the main
bed frame, the adjustable bed carriage having: at least one first
leg having an upper end slidably attached to the first end of the
main bed frame; at least one second leg having an upper end pivotably
attached to the second end of the main bed frame; each of said at
least one first leg and said at least one second leg being pivotably
connected to each other at a central pivot located substantially
at a midpoint of each said leg, to permit pivoting movement of each
of said at least one first leg and at least one second leg about
the central pivot in opposite directions to move the adjustable
bed carriage between an extended condition and a retracted condition,
moving the main bed frame relative to the plane of the floor; at
least one motor mounted on the main bed frame and coupled to said
at least one second leg; and said at least one motor being adapted
to push the lower end of said at least one second leg away from
the main bed frame and to pull the lower end of said at least one
second leg toward the main bed frame.
2. A linkage assembly for supporting a main bed frame above a substantially
planar floor, the linkage assembly having: at least one first leg
having an upper end slidably attached to a first end of the main
bed frame; at least one second leg having an upper end pivotably
attached to the main bed frame; each of said at least one first
leg and said at least one second leg being pivotably connected to
each other at a central pivot located substantially at a midpoint
of said at least one first leg, to permit pivoting movement of said
at least one first leg and corresponding movement of said at least
one second leg, to move the linkage assembly between an extended
condition, in which the main bed frame is in a fully raised position,
and a retracted condition, in which the main bed frame is in a fully
lowered position; said at least one first leg including at least
one caster base positioned distal to the first end of the main bed
frame, said at least one caster base including at least one caster
for engaging the floor; said at least one caster base being disposed
in a preselected position relative to the plane of the floor when
the linkage assembly is in the extended condition; at least one
follower strut having an upper end and a lower end, the lower end
being pivotably attached to said at least one caster base; and the
upper end of said at least one follower strut being attached to
said at least one second leg at a predetermined pivot point above
the central pivot, the predetermined pivot point being selected
such that said at least one follower strut maintains said at least
one caster base substantially in the preselected position relative
to the plane of the floor as the linkage assembly moves between
the extended and the retracted conditions.
3. A linkage assembly according to claim 2 in which said at least
one second leg includes at least one wheel mounted at a lower end
of said at least one second leg disposed distal to the second end
of the main frame, for engaging the floor.
4. A linkage assembly according to claim 2 in which said at least
one caster base includes at least one locator element to which the
lower end of said at least one follower strut is pivotably attached,
said at least one locator element being positioned to locate the
lower end of the follower strut such that said at least one caster
base is maintained substantially in the preselected position relative
to the plane of the floor as the linkage assembly moves between
the extended condition and the retracted condition.
5. A linkage assembly according to claim 4 in which the main bed
frame defines a footprint periphery beneath the main bed frame and
said at least one caster base includes a caster base body portion
and at least one mounting bracket adapted to receive said at least
one caster, said at least one mounting bracket extending from the
caster base body portion to locate said at least one caster such
that at least a portion of said at least one caster is positionable
proximate to the footprint periphery.
6. An adjustable bed for use on a substantially planar floor, the
adjustable bed having: a main frame for supporting a mattress, the
main frame having a first end and a second end; a scissor leg assembly
for supporting the main frame; a motor mounted on the main frame
and attached to the scissor leg assembly, for causing the scissor
leg assembly to move between an extended condition, in which the
main frame is in a fully raised position, and a retracted condition,
in which the main frame is in a fully lowered position; the scissor
leg assembly including: a first pair of legs having a proximal end
slidably attached to the main frame at the first end and a second
pair of legs having a proximal end pivotably attached to the main
frame at the second end; the first pair of legs including at least
one caster for engaging the floor and positioned in at least one
caster base mounted at a distal end thereof positioned distal to
the first end of the main frame; said at least one caster base being
disposed in a preselected position relative to the plane of the
floor when the scissor leg assembly is in the extended condition;
the second pair of legs having at least one wheel for engaging the
floor and mounted at a distal end thereof positioned distal to the
second end of the main frame; the first and second pairs of legs
being pivotably connected to each other at substantially coplanar
central pivot points disposed substantially midway between the proximal
ends and the distal ends of each said pairs of legs respectively,
such that the scissor leg assembly is movable between the extended
condition and the retracted condition; at least one follower strut
having an upper end and a lower end, the lower end being pivotably
attached to said at least one caster base; the upper end of said
at least one follower strut being pivotably attached to at least
one of said legs in said second pair of legs at a predetermined
pivot point located between said central pivot point and the proximal
end of said second pair of legs; and said at least one predetermined
pivot point being selected such that said at least one follower
strut maintains said at least one caster base substantially in the
preselected position relative to the plane of the floor as the scissor
leg assembly moves between the extended condition and the retracted
condition.
7. An adjustable bed according to claim 6 in which said at least
one caster base includes: at least one locator element to which
the lower end of said at least one follower strut is pivotably attached,
said at least one element being positioned relative to the predetermined
pivot point location such that said at least one follower strut
maintains said at least one caster base substantially in the preselected
position relative to the plane of the floor as the main frame is
moved between the fully raised and the fully lowered positions.
8. An adjustable bed according to claim 6 in which the main bed
frame defines a footprint periphery beneath the main bed frame and
said at least one caster base includes a caster base body portion
and at least one mounting bracket adapted to receive said at least
one caster, said at least one mounting bracket extending from said
caster base body portion to locate said at least one caster such
that at least a portion of said at least one caster is positionable
proximate to the footprint periphery.
9. An adjustable bed according to claim 6 in which: said at least
one caster includes a caster housing pivotably attached to a caster
stem and a caster wheel mounted in the caster housing for rotation
about a caster wheel axis; said at least one caster being operable
between an unlocked condition, in which the caster wheel is rotatable
about the caster wheel axis and the caster housing is pivotable
about the caster stem, and a locked condition, in which a caster
lock prevents rotation of the caster wheel and pivoting of the caster
housing; an actuator assembly for actuating the caster lock to the
locked condition, the actuator assembly including: a lock bar for
activating the caster lock, the lock bar being movable between an
activated position, in which the caster lock is activated, and a
deactivated position, in which the caster lock is deactivated; an
actuator positioned on the main bed frame, for engaging the lock
bar when the main bed frame is moved downwardly to an engagement
position; the actuator engaging the lock bar and urging the lock
bar to the activated position, thereby activating the caster lock,
when the main bed frame is moved downwardly to the engagement position.
10. An adjustable bed according to claim 9 in which the actuator
assembly additionally includes a release element movable between
an inactive position and a release position, the release element
being operable to move the lock bar to the deactivated position
when the release element is moved to the release position.
11. An adjustable bed according to claim 10 in which the actuator
includes a tab adapted for engagement with the lock bar upon movement
of the main bed frame downwardly to the engagement position, for
activation of the lock bar.
12. An adjustable bed according to claim 10 in which the actuator
assembly includes a release mechanism for releasing the tab from
engagement with the lock bar for deactivation of the lock bar.
13. An adjustable bed according to claim 6 in which each of said
legs in said first pair of legs and said second pair of legs is
configured to provide a predetermined clearance between the adjustable
bed and the floor when the main bed frame is in the fully lowered
position.
14. A lock actuator assembly for activating and deactivating at
least one caster lock included in at least one caster, said at least
one caster being included in an adjustable bed carriage supporting
a main bed frame, the lock actuator assembly having: an activation
assembly mounted on the adjustable bed carriage; the activation
assembly being adapted for activating said at least one caster lock;
and an actuator mounted on the main bed frame, the main bed frame
being movable by the adjustable bed carriage between a fully raised
position, in which the adjustable bed carriage is in an extended
condition, and a lowered position, in which the adjustable bed carriage
is in a retracted condition, the actuator being positioned for activation
of the activation assembly upon the main bed frame reaching an engagement
position relative to the activation assembly as the main bed frame
is lowered; and the actuator being adapted for de-actuating the
activation assembly.
15. A lock actuator assembly according to claim 14 in which: the
activation assembly includes a lock bar for activating said at least
one caster lock; the lock bar being movable between an activated
position, in which said at least one caster lock is activated, and
a deactivated position, in which said at last one caster lock is
deactivated; the actuator being positioned on the main bed frame
for engaging the lock bar when the main bed frame is lowered to
the predetermined engagement position; and the actuator urging the
lock bar to the activation position upon engagement therewith.
16. A lock actuator assembly according to claim 15 additionally
including a release element movable between an inactive position,
in which the release element is disengaged from the lock bar, and
an active position, in which the release element urges the actuator
out of engagement with the lock bar.
Description FIELD OF THE INVENTION
This invention relates to an adjustable bed carriage for supporting
a main bed frame.
BACKGROUND OF THE INVENTION
Known adjustable bed carriages are generally of three types. One
type of adjustable bed carriage includes leg assemblies which are
positioned at both ends of a main bed frame. An example of this
type of known adjustable bed carriage is disclosed in U.S. Pat.
No. 4023849 (Bethlen).
A second general type includes extendable linkages at both ends
of the main bed frame. For instance, such an adjustable bed carriage
is disclosed in U.S. Pat. No. 4097939 (Peck et al.).
The other well-known type of adjustable bed carriage includes a
base supported by casters, wheels or feet on which legs (or linkages),
are positioned, extending upwardly to the main bed frame. U.S. Pat.
No. 3462772 (Morrison) discloses an example of this general type
of known adjustable bed carriage.
Scissor leg assemblies are also known and can provide relative
simplicity and generally greater overall strength and stability.
However, scissor leg assemblies have not generally been used in
adjustable bed carriages, and those that have suffer from some deficiencies.
For example, in U.S. Pat. No. 5613255 (Bish et al.), an adjustable
bed carriage is disclosed in which two scissor leg assemblies support
the main bed frame. However, the Bish et al. adjustable bed carriage
is relatively complex, involving a relatively large number of components.
In particular, the two scissor leg assemblies are shown (in FIGS.
4 and 5 of Bish et al.) to include a number of slidable connections
between the scissor leg assemblies and a base and a main bed frame.
Such slidable connections should be minimized in order to reduce
manufacturing costs.
There is therefore a need for an improved adjustable bed carriage
for supporting a main bed frame.
SUMMARY OF THE INVENTION
In a broad aspect, the invention provides an adjustable bed carriage
for supporting a main bed frame above a substantially planar floor.
The adjustable bed carriage has a first leg with an upper end slidably
attached to a first end of the main bed frame and a second leg with
an upper end pivotably attached to a second end of the main bed
frame. Each of the first leg and the second leg are pivotably connected
to each other at a central pivot located substantially at a midpoint
of each, to permit pivoting movement of each of the first leg and
the second leg about the central pivot in opposite directions. The
pivoting movement of the legs moves the adjustable bed carriage
between a fully extended condition and a fully collapsed condition.
In another aspect, the invention provides an adjustable bed for
use on a substantially planar floor. The adjustable bed includes
a main bed frame, having a first end and a second end, and an adjustable
bed carriage for supporting the main bed frame. The adjustable bed
carriage has a first leg having an upper end slidably attached to
the first end of the main bed frame and a second leg having an upper
end pivotably attached to the second end of the main bed frame.
Each of the first leg and the second leg are pivotably connected
to each other at a central pivot located substantially at a midpoint
of each leg to permit pivoting movement of each of the first leg
and the second leg about the central pivot in the opposite directions.
The pivoting movement of the legs moves the adjustable bed carriage
between an extended condition and a retracted condition, moving
the main bed frame relative to the plane of the floor.
In another aspect, the first leg includes a first leg base mounted
on a lower end of the first leg for engaging the floor, and the
second leg includes a second leg base mounted on a lower end of
the second leg for engaging the floor.
In yet another aspect, the invention includes a motor mounted on
the main bed frame and coupled to the adjustable bed carriage. The
motor is adapted b act upon the adjustable bed carriage to move
the adjustable bed carriage between the extended condition and the
retracted condition.
In yet another aspect, the invention provides an adjustable bed
for use on a substantially planar floor. The adjustable bed has
a main frame for supporting a mattress, the main frame having a
first end and a second end, a scissor leg assembly for supporting
the main frame, and a motor mounted on the main frame and attached
to the scissor leg assembly, for causing the scissor leg assembly
to move between an extended condition, in which the main frame is
in a fully raised position, and a retracted condition, in which
the main frame is in a fully lowered position.
The scissor leg assembly includes a first pair of legs having a
proximal end slidably attached to the main frame at the first end
and a second pair of legs having a proximal end pivotably attached
to the main frame at the second end. The first pair of legs includes
one or more casters for engaging the floor and positioned in a caster
base mounted at a distal end thereof positioned distal to the first
end of the main frame. The caster base is disposed in a preselected
position relative to the plane of the floor when the scissor leg
assembly is in the extended condition. The second pair of legs has
one or more wheels for engaging the floor and mounted at a distal
end thereof positioned distal to the second end of the main frame.
The first and second pairs of legs are pivotably connected to each
other at substantially coplanar central pivot points disposed substantially
midway between the proximal ends and the distal ends of each said
pairs of legs respectively, so that the scissor leg assembly is
movable between the extended condition and the retracted condition.
The scissor leg assembly also includes one or more follower struts,
each with an upper end and a lower end. The lower end of each follower
strut is pivotably attached to the caster base. The upper end of
each follower strut is pivotably attached to the second pair of
legs at a predetermined pivot point located between the central
pivot point and the proximal end of the second pair of legs. The
predetermined pivot point is selected so that each follower strut
maintains the caster base substantially in the preselected position
relative to the plane of the floor as the scissor leg assembly moves
between the extended condition and the retracted condition.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood with reference to the drawings,
in which:
FIG. 1 is an isometric view of a preferred embodiment of an adjustable
bed carriage as well as a main bed frame positioned thereon, the
adjustable bed carriage being shown in an extended condition;
FIG. 2 is an isometric view of the back and bottom of the adjustable
bed carriage of FIG. 1 and of the main bed frame;
FIG. 3 is a side view of a right side of the adjustable bed carriage
of FIG. 1 and of the main bed frame;
FIG. 4 is a side view of a left side of the adjustable bed carriage
of FIG. 1 and of the main bed frame;
FIG. 5 is a side view of the right side of the adjustable bed carriage
of FIG. 1 with the main bed frame positioned thereon, and showing
the adjustable bed carriage in a retracted condition;
FIG. 6 is a side view of the left side of the adjustable bed carriage
of FIG. 1 and of the main bed frame in the retracted condition;
FIG. 7 is a side view of the front side of the adjustable bed carriage
of FIG. 1 in the extended condition and of the main bed frame;
FIG. 8 is a side view of the rear side of the adjustable bed carriage
of FIG. 1 in the extended condition and of the main bed frame;
FIG. 9A is a top view of the adjustable bed carriage of FIG. 1
in the extended condition, as well as the main bed frame;
FIG. 9B is a section view of the adjustable bed carriage of FIG.
9A and the main bed frame, taken along line A--A in FIG. 9A;
FIG. 10 is a bottom view of the adjustable bed carriage of FIG.
1 in the extended condition and of the main bed frame;
FIG. 11A is a top view of the adjustable bed carriage of FIG. 1
in the retracted condition and the main bed frame, drawn at a larger
scale;
FIG. 11B is a section view of the adjustable bed carriage of FIG.
11A and the main bed frame taken along line B--B in FIG. 11A;
FIG. 12A is a side view of the adjustable bed carriage of FIG.
1 in the extended condition and the main bed frame;
FIG. 12B is a side view of a caster base included in the adjustable
bed carriage of FIG. 12A, drawn at a larger scale;
FIG. 13A is a side view of the adjustable bed carriage of FIG.
12A and the main bed frame, showing the adjustable bed carriage
in a first intermediate condition, drawn at a smaller scale;
FIG. 13B is a side view of the caster base included in the adjustable
bed carriage of FIG. 13A, drawn at a larger scale;
FIG. 14A is a side view of the adjustable bed carriage of FIG.
12A and the main bed frame, with the adjustable bed carriage in
a second intermediate condition, drawn at a smaller scale;
FIG. 14B is a side view of the caster base included in the adjustable
bed carriage of FIG. 14A, drawn at a larger scale;
FIG. 15A is a side view of the adjustable bed carriage of FIG.
12A and the main bed frame, with the adjustable bed carriage in
the retracted condition, drawn at a smaller scale;
FIG. 15B is a side view of the caster base included in the adjustable
bed carriage of FIG. 15A, drawn at a larger scale;
FIG. 16A is a bottom view of an alternative embodiment of the adjustable
bed, drawn at a smaller scale;
FIG. 16B is a section view of the adjustable bed of FIG. 16A, taken
along line C--C in FIG. 16A;
FIG. 17 is a side view of an alternative embodiment of the adjustable
bed showing the adjustable bed carriage in the retracted condition;
FIG. 18 is a side view of another alternative embodiment of the
adjustable bed showing the adjustable bed carriage in the retracted
condition;
FIG. 19 is an isometric view of another alternative embodiment
of an adjustable bed of the invention including an actuator assembly
positioned at a front end of the adjustable bed, the adjustable
bed carriage thereof being shown in an intermediate condition, drawn
at a smaller scale;
FIG. 20 is an isometric view of the adjustable bed of FIG. 19
showing the adjustable bed carriage in a retracted condition;
FIG. 21A is an isometric view of the front end of the adjustable
bed of FIG. 19 showing the adjustable bed carriage in the intermediate
condition, drawn at a larger scale;
FIG. 21B is an isometric view of the front end of the adjustable
bed of FIG. 20 showing the adjustable bed carriage in the retracted
condition;
FIG. 21C is an isometric view of the front end of the adjustable
bed of FIG. 20 showing the adjustable bed carriage in the retracted
condition showing a release mechanism in a released position;
FIG. 21D is a partial isometric view of the actuator assembly and
part of the adjustable bed showing the release mechanism in the
released position in dotted outline;
FIG. 21E is a top view of the actuator assembly of FIG. 21D, showing
the release mechanism in unreleased and released positions;
FIG. 21F is a front view of the actuator assembly of FIG. 21D,
showing the release mechanism in unreleased and released positions;
FIG. 22 is a side view of the adjustable bed of FIG. 19 drawn
at a smaller scale;
FIG. 23 is an elevation view of the front end of the adjustable
bed of FIG. 22; and
FIG. 24 is a bottom view of the adjustable bed of FIG. 22.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
Reference is first made to FIGS. 1-8 9A, 9B and 10 to describe
a preferred embodiment of an adjustable bed carriage indicated generally
by the numeral 30 in accordance with the invention. The adjustable
bed carriage 30 is for supporting a main bed frame 32 above a substantially
planar floor 34. In the preferred embodiment, the adjustable bed
carriage 30 has first legs 40 41 with upper ends 42 43 respectively.
Each upper end 42 43 is slidably attached to a first end 44 of
the main bed frame 32 as will be described. As can be seen in FIGS.
1 and 2 the adjustable bed carriage 30 also includes second legs
46 47 with upper ends 48 49 respectively, and each upper end 48
49 is pivotably attached at a second end 50 of the main bed frame
32. In addition, each of the first legs 40 41 and the second legs,
46 47 are pivotably connected respectively at central pivots 52
53 located substantially at the midpoints of the legs 40 41 and
46 47. The connections of the legs 40 41 and 46 47 at the central
pivots 52 53 permits pivoting movement of the legs 40 41 and 46
47 respectively about the central pivots 52 53 in opposite directions,
as will be described. The pivoting movement of the legs 40 41 and
46 47 about the central pivots 52 53 respectively moves the adjustable
bed carriage 30 between an extended condition (FIGS. 1-4 7 8
9A, 9B and 10) and a retracted condition (FIGS. 5 6).
In the preferred embodiment, pivoting movement of the legs 46
47 results in a corresponding pivoting movement of the legs 40
41 to move the adjustable bed carriage between the extended condition
and the retracted condition, so that the main bed frame 32 is thereby
moved between a fully raised position (FIGS. 1-4 7 8) in which
the adjustable bed carriage 30 is in the extended condition and
a fully lowered position (FIGS. 5 6), in which the adjustable bed
carriage 30 is in the retracted condition. For example, as shown
in FIG. 3 pivoting movement of the leg 46 in the direction indicated
by arrow "A" would result in pivoting movement of the
leg 40 in the direction of arrow "B". Also, the pivoting
movement of the second leg 46 results in sliding movement of the
upper end of the first leg 40 in the direction of arrow "X"
in FIG. 3.
As can be seen in FIGS. 1-8 the first legs 40 41 preferably include
a first leg base 54 and the second legs 46 47 preferably include
one or more second leg bases 56. In the preferred embodiment, the
first leg base 54 includes one or more casters 58 and the second
leg base 56 includes one or more wheels 60. It will be appreciated
by those skilled in the art, however, that various devices may be
included in the first leg base 54 and the second leg base 56 for
engaging the floor 34. For example, each of the first leg base 54
and the second leg base 56 may include one or more casters, one
or more wheels, or one or more feet for engaging the floor 34.
A preferred embodiment of an adjustable bed 64 of the invention
includes the main bed frame 32 and the adjustable bed carriage 30
for supporting the main bed frame 32 on a substantially planar floor
34. Preferably, the adjustable bed 64 includes a motor 66 mounted
on the main bed frame 32 and coupled to the adjustable bed carriage
30 for positioning the adjustable bed carriage 30. Although various
types of motors could be used, the preferred motor 66 is a linear
screw drive motor powered by electricity, as is known in the art.
As shown in FIG. 9B, the motor 66 is preferably pivotably mounted
on the main bed frame 32 and pivotably mounted on the second leg
46. In the preferred embodiment, the second legs 46 47 each include
a downwardly depending flange 68 in which a distal end 70 of the
motor 66 is mounted, as will be described. When the adjustable bed
carriage 30 is to be moved from the extended condition (FIG. 9B)
(or from an intermediate position) to or towards the retracted condition,
a movable portion 72 is retracted into a motor body 74 in a controlled
manner, in the direction shown by arrow "C" in FIG. 9B.
When the adjustable bed carriage 30 is to be moved from the retracted
condition (FIG. 11B) (or from an intermediate position) to or towards
the extended condition, the movable portion 72 is pushed outwardly
from the motor body 74 in the direction of arrow "D" in
FIG. 11B.
In the preferred embodiment, the adjustable bed 64 includes a linkage
assembly (also referred to as a scissor leg assembly) 74 which includes
the adjustable bed carriage 30 with follower struts 78 79 (FIGS.
1-4), as will be described. As can be seen in FIGS. 1-4 the first
legs 40 41 include a caster base 80 positioned distal to the first
end 44 of the main bed frame 32. The caster base 80 includes one
or more casters 58 for engaging the floor 34.
Preferably, the caster base 80 is disposed in a preselected position
relative to the plane 36 of the floor 34 when the linkage assembly
is in the extended condition, as shown in FIGS. 12A, 12B. The follower
struts 78 79 each have respective upper ends 81 82 and lower ends
83 84. As can be seen in FIGS. 1 2 and 9B, in the preferred embodiment,
the lower ends 83 84 are pivotably attached to the caster base
80. The upper ends 81 82 of the follower struts 78 79 are pivotably
attached to the second legs 46 47 respectively (FIG. 9B). This
pivotable attachment is at predetermined pivot points 86 87 on
the second legs 46 47 above the central pivots 52 53. The predetermined
pivot points 86 87 are selected so that the follower struts 78
79 can act on the caster base 80 to maintain the caster base 80
substantially in the preselected position relative to the plane
36 of the floor 34 as the linkage assembly 76 moves between the
extended and retracted conditions.
As can be seen in FIGS. 12A, 12B, 13A, 13B, 14A, 14B, 15A, and
15B, in the preferred embodiment, the follower struts 78 79 only
maintain the caster base 80 in substantially the preselected position
relative to the plane 36. Generally, for example, a top surface
88 which is substantially planar is approximately horizontal in
FIG. 12A. However, the top surface 88 may be gradually inclined,
up to approximately 3-5.degree. from the horizontal (FIGS. 13B,
14B, 15B), as the linkage assembly is moved to the retracted position.
The follower struts 78 79 form a "modified" parallelogram
with the legs 40 41 and portions of the legs 46 47 i.e., they
preferably do not form a perfect parallelogram. The location of
the follower struts does not provide perfect alignment, as a perfect
parallelogram would, but is optimized to provide the best alignment
possible. As the bed is raised, the angle changes above and below
horizontal so that the bed has a level surface at the highest and
lowest positions while maintaining a substantially level surface
through the range of motion from high to low.
In the preferred embodiment, the caster base 80 includes one or
more locator elements 89 90 to which the lower ends 83 84 of the
follower struts 78 79 are pivotably attached. Each of the locator
elements 89 90 is positioned so as to enable the follower struts
78 79 to maintain the caster base 80 in substantially the preselected
position relative to the plane 36 of the floor 34.
Preferably, main bed frame 32 defines a footprint periphery 90
circumscribing the perimeter of the main bed frame 32 (FIGS. 9A,
10 11A). In addition, the caster base 80 includes one or more mounting
brackets 94 positioned, at least in part, adjacent to footprint
periphery 92. Due to the positioning of the mounting brackets 94
caster locks on the casters 58 are readily accessible by the operator,
even when the adjustable bed carriage 30 is in the retracted condition,
as shown in FIG. 11A.
In use, the motor 66 is activated by a switch or other control
means (not shown), as is known in the art, if movement of the linkage
assembly 76 between the extended condition and the retracted condition,
and consequent movement of the main bed frame 32 relative to the
plane 36 of the floor 34 is desired. For example, referring to
FIGS. 12A, 13A, 14A, and 15A, to move the linkage assembly 76 from
the extended condition (FIG. 12A) to the retracted condition (FIG.
51A), the movable portion 72 is retracted into the motor body 74.
Retracting of the movable portion 72 is controlled by an electric
motor in the motor body 74 thereby ensuring that the retracting
is at a desired rate (i.e., controlled by an operator (not shown)).
Also, as will be appreciated by those skilled in the art, the retraction
could be stopped, if the operator wishes to have the linkage assembly
remain at any position intermediate between the extended and retracted
conditions. The motor 66 holds the adjustable bed carriage 30 in
the intermediate position.
Preferably, and as shown in FIG. 9B, the motor 66 is pivotably
mounted to a flange 96 which is secured to the main bed frame 32.
The flange 96 is positioned so as to locate an upper end 97 of the
motor 66 as high (in relation to the plane 36 of the floor 34) as
is feasible. Also, the flange 96 is positioned as low (in relation
to the plane 36 of the floor 34) as is feasible. The result is that
the initial raising force required to raise the linkage assembly
from the retracted condition (FIGS. 11B, 15B) is relatively low.
It will be appreciated by those skilled in the art that the main
bed frame 32 can comprise a chassis portion 98 and deck portions
100 mounted on the chassis portion 98 (FIG. 2). The main deck portions
100 (which would support a mattress (not shown) when in use) are
positionable in a variety of positions relative to the chassis portion
98 as is known in the art. For example, the deck portions 100 are
positionable so as to allow adjustable head and foot elevation,
so that the patient can be positioned as necessary. Preferably,
motors 102 are used to position deck portions 100 accordingly, as
is known in the art.
Preferably, the legs 40 41 and 46 47 are configured so as to
provide maximum clearance between the floor 34 and the adjustable
bed carriage 30 through a middle portion of the adjustable bed carriage
30 when in the retracted condition (FIGS. 5 6). As shown in FIGS.
5 and 6 because the legs 40 41 and 46 47 each include lower ends
which are bent relative to the substantially straight elongate other
portions of the legs 40 41 46 47 such clearance is provided
in the middle portion of the adjustable bed carriage 30 when the
adjustable bed carriage is in the retracted condition. Preferably,
the bent portion is aligned at a significant angle (e.g., up to
approximately 11.5.degree.) from the axis of the main portions of
each leg. Due to the clearance, lift devices, movable tables and
other devices for use by or with a patient (not shown) which require
clearance under the adjustable bed carriage 30 for their operation
can be used, when the adjustable bed carriage 30 is at any height.
The adjustable bed carriage 30 has the advantage of including slidable
connections only where the first legs 40 41 are connected to the
main bed frame 32. The second legs 46 47 are only pivotably connected
to the main bed frame 32 rather than also being slidably connected.
The cost of manufacturing the adjustable bed carriage 30 is thereby
significantly reduced, and its operation is much simpler, and therefore
more reliable.
In another embodiment, as shown in FIGS. 16A and 16B, an adjustable
bed 164 has an adjustable bed carriage 130 in which the first legs
140 141 are pivotably connected to the main bed frame 132 at a
first end 144 and the second legs 146 147 are slidably connected
to the main bed frame 132 at a second end 150. As can be seen in
FIG. 16b, the motor 66 is preferably mounted on the main bed frame
132 and pivotably connected to the adjustable bed carriage 130.
More particularly, the motor 66 is preferably pivotably connected
to the second legs 46 47 at a point below the central pivots.
In an alternative embodiment, shown in FIG. 17 an adjustable bed
carriage 230 includes a first leg base 254 including one or more
foot elements 262 for engaging the floor 34. As can be seen in FIG.
17 the adjustable bed carriage 230 additionally includes a second
leg base 256 including wheels 260.
In another alternative embodiment, an adjustable bed 364 includes
one or more casters 363 mounted on the main bed frame 332. As shown
in FIG. 18 the casters 63 are mounted so that, when the adjustable
bed carriage 330 is in the retracted condition, the casters 363
engage the floor 34. Accordingly, the adjustable bed 364 can be
moved on the casters 363 when the adjustable bed carriage 330 is
in the retracted condition.
In another alternative embodiment, an adjustable bed 464 (shown
in FIGS. 19 20 21A-F, and 22-24) includes a lock actuator assembly
404. Preferably, the adjustable bed 464 includes a main bed frame
432 supported by an adjustable bed carriage 430 which includes one
or more casters 458. It is preferred that, as is known in the art,
casters 458 on the adjustable bed 464 include caster locks (not
shown). For example, a Tente-Rollen model 2946 UAP 100 R26-28S45
includes a caster lock which, when activated, prevents rotation
of a caster wheel about a caster wheel axis and also prevents a
caster housing (in which the caster wheel is mounted) from pivoting
about a caster stem.
Other locking means can be used instead of caster locks. For example,
the adjustable bed carriage could include a foot assembly (not shown),
movable between a lowered position, in which the foot engages the
floor and supports the main bed frame above its usual position,
so that the caster is raised off the floor, and a raised position
in which the foot does not engage the floor. In this alternative
embodiment, the lock actuator assembly actuates the foot, causing
it to move to the lowered position, upon the occurrence of a triggering
event.
Preferably, the lock actuator assembly 404 includes a lock bar
406 secured in two connectors 408 one located at each end 410 of
the lock bar 406 (FIGS. 19 21A, 21B). The connectors 408 are in
turn each secured to activators 412 respectively. The lock bar 406
is movable between an activated position (FIG. 20), in which the
connectors 408 cause the activators 412 to activate the caster locks,
and a deactivated position (FIG. 19), in which the activators 412
are maintained in a position which does not result in activation
of the caster locks. Movement of the lock bar 406 from the deactivated
position to the activated position results in rotation of the activators
412. This in turn causes the caster locks to lock. Movement of the
lock bar 406 from the activated position to the deactivated position
causes rotation of the activators in the other directions, so that
the caster locks are thereby unlocked.
Preferably, an actuator 414 is mounted on the main bed frame 432
for engaging the lock bar 406 when the main bed frame 432 is moved
downwardly to an engagement position (FIG. 20). The lock bar 406
is normally in the deactivated position. It is preferred that the
engagement position be at a height which is close (i.e., a relatively
small distance above) to the main bed frame's fully lowered position.
Upon the main bed frame 432 being lowered to the engagement position,
the actuator 414 engages the lock bar 406 urging the lock bar 406
to move from the deactivated position (FIG. 19) to the activated
position (FIG. 20). The caster lock is thereby activated.
The actuator assembly 404 also includes a release plate 416 which
is engageable with the actuator 414. As can be seen in FIGS. 21C,
21D, 21E, and 21F, the release plate 416 is attached to the frame
432 by a pin 418 about which the release plate 416 is pivotable.
The release plate includes a bevelled edge 420 which is positioned
adjacent to the actuator 414. As can be seen in FIG. 21F, the actuator
414 is also attached to the main bed frame 432 by an actuator pin
422 about which the actuator is also pivotable.
Preferably, the bevelled edge 420 forms a cam surface so that,
when the release plate 416 is pivoted about the pin 418 the bevelled
edge 420 in turn engages the actuator 414 causing the actuator
414 to move, as follows. As can be seen in FIG. 21E, movement of
the release plate 416 from an unreleased position (designated as
"U" in FIG. 21E) to a released position (designated as
"R" in FIG. 21E) causes the edge 420 to be pushed against
the actuator 414. This in turn causes the actuator 414 to pivot
about the actuator pin 422 resulting in the disengagement of the
actuator 414 from the lock bar 406. In pivoting about the actuator
pin 422 the actuator 414 moves from the engaged position (shown
as "E" in FIG. 21F) to the disengaged position (shown
as "D" in FIG. 21F).
The lock bar 406 is intended to be kept in the locked position
during use. The unlocked position is only required when moving the
bed, with or without the patient. If casters are not locked, problems
can result when the patient is trying to enter or exit the bed with
no assistance. The automatic activation of a locking mechanism helps
solve the problem of accidentally leaving the bed in the unlocked
position, where the patient may be vulnerable to unexpected movement
of the bed. In practice, the bed is typically lowered to its lowest
height for sleeping, or when no treatment is required.
It will be evident to those skilled in the art that the invention
can take many forms, and that such forms are within the scope of
the invention as claimed. Therefore, the spirit and scope of the
appended claims should not be limited to the description of the
preferred versions contained herein. |