U.S. patent application number 09/739910 was filed with the patent office on 2001-12-06 for height and angle adjustable bed having a rolling base.
Invention is credited to Megown, Michael W..
Application Number | 20010047546 09/739910 |
Document ID | / |
Family ID | 26896208 |
Filed Date | 2001-12-06 |
United States Patent
Application |
20010047546 |
Kind Code |
A1 |
Megown, Michael W. |
December 6, 2001 |
Height and angle adjustable bed having a rolling base
Abstract
A height and angle adjustable bed having a rolling base which
utilizes a unique pivoting base having castors and a unique support
arm assist spring mechanism. The pivoting castor base allows
movement of the bed in any direction on the plane of the floor when
also positioned at any user desired height while also providing a
stable and lockable support for the bed. The support arm spring
mechanism provides an initial assist force when the bed is in a
nearly or fully lowered position and thereby minimizes the force
required by the linear actuators used to raise the bed.
Inventors: |
Megown, Michael W.; (St.
Louis, MO) |
Correspondence
Address: |
KEVIN L KLUG
ATTORNEY AT LAW
11237 CONCORD VILLAGE AVENUE
ST. LOUIS
MO
63123-2273
US
|
Family ID: |
26896208 |
Appl. No.: |
09/739910 |
Filed: |
December 19, 2000 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60200902 |
May 1, 2000 |
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Current U.S.
Class: |
5/611 |
Current CPC
Class: |
A61G 7/005 20130101;
A61G 7/0528 20161101; A47C 19/045 20130101; A61G 7/012
20130101 |
Class at
Publication: |
5/611 |
International
Class: |
A47B 007/00 |
Claims
What is claimed is:
1. A height and angle adjustable bed having a rolling base which is
capable of rolling upon a floor plane comprising: a bed frame
having a head, foot, right, left, and central portion; and one or
more bed support arms pivotably attached to said bed frame; and at
least one linear actuator pivotably attached to at least one of
said support arms and said bed frame; and at least one castor base
pivotably attached to at least one of said support arms near the
floor plane; and said castor base comprising a castor frame having
three or more castors mounted thereon in a substantially polygonal
form, whereby said castors of said polygonal form rest upon the
floor plane and maintain said castor base stable yet moveable in
the floor plane.
2. The height and angle adjustable bed having a rolling base as set
forth in claim 1 further comprising: an assist arm mounted onto at
least one of said bed support arms near said pivotal attachment
with said bed frame; and an actuator assist spring mechanism
located between said assist arm and said bed frame, whereby said
actuator assist spring mechanism provides an assist force onto said
support arm when said bed frame is placed in a nearly or fully
lowered position.
3. The height and angle adjustable bed having a rolling base as set
forth in claim 1 further comprising: two or more support arm wheels
each rotatably mounted onto a base shaft; and said base shafts
mounted onto at least one of said support arms near the floor plane
and also opposite said castor base.
4. The height and angle adjustable bed having a rolling base as set
forth in claim 1, said castor frame further comprising: two or more
frame arms each having two ends; and each of said frame arms having
an arm hole near each of said ends, whereby a castor mounting stud
may mount within; and two or more frame ears, each frame ear
mounted onto a frame arm; and each of said frame ears having an ear
hole; whereby a base shaft integrally mounted with each of said bed
support arms may pivotably attach said castor base through said ear
holes.
5. The height and angle adjustable bed having a rolling base as set
forth in claim 4, said castor frame further comprising: said frame
arms rigidly connected together with a frame support angle to form
a substantially "H" shaped member.
6. The height and angle adjustable bed having a rolling base as set
forth in claim 1, said one or more of said castors further
comprising: a castor locking brake capable of pivotably locking
said castor on a castor mounting stud and rotationally locking a
castor wheel.
7. The height and angle adjustable bed having a rolling base as set
forth in claim 4, said one or more of said castors further
comprising: a castor locking brake capable of pivotably locking
said castor on said castor mounting stud and rotationally locking a
castor wheel.
8. The height and angle adjustable bed having a rolling base as set
forth in claim 2 the actuator assist spring mechanism further
comprising: a spring shaft having two ends and placed through an
assist spring; and an assist guide integrally mounted onto said bed
frame, said assist guide having a guide hole therein of smaller
diameter than an outside diameter of said assist spring and through
which one of said ends of said spring shaft is placed; and an arm
slot in said assist arm, said arm slot having a width less than
said outside diameter of said assist spring and through which
another of said ends of said spring shaft is placed; and at least
one shaft keeper near at least one of said spring shaft ends,
whereby said shaft keeper holds said spring shaft in place within
said guide hole and said arm slot and further allows compression of
said assist spring between said assist arm and said assist guide to
create said assist force onto said support arm when said bed frame
is placed in a nearly or fully lowered position.
9. A height and angle adjustable bed having a rolling base
comprising: a bed frame having a head, foot, right, left, top,
bottom and central portion; and four support flanges mounted on
said bottom portion of said bed frame near said central portion
whereby two support flanges are mounted near the left portion and
two support flanges are mounted near the right portion, each of
said support flanges having a flange hole; and four bed support
arms each having two ends and an arm hole near one of said ends,
each of said bed support arms pivotably attached to one each of
said support flanges with a support shaft placed through each of
said arm holes and said flange holes; and a first crossarm rigidly
mounted between two support arms nearest the foot portion of the
bed; and a second crossarm rigidly mounted between two support arms
nearest the head portion of the bed; and a first base tube having
two ends and rigidly mounted between two support arms nearest the
foot portion of the bed and opposite said support flanges; and a
second base tube having two ends and rigidly mounted between two
support arms nearest the head portion of the bed and opposite said
support flanges; and a first linear actuator pivotably attached
between said first crossarm and said bed frame near said foot
portion; and a second linear actuator pivotably attached between
said second crossarm and said bed frame near said head portion; and
four base shafts each mounted within and extending from one each of
said ends of each of said first and second base tubes; and a castor
base pivotably attached to said base shafts extending from said
first base tube; and said castor base comprising a castor frame
having four castors mounted thereon in a substantially polygonal
form, whereby said castors of said polygonal form rest upon a plane
of a floor and maintain said castor base stable yet moveable in the
plane of said floor; and two support arm wheels each rotatably
mounted onto one each of said base shafts extending from said
second base tube.
10. The height and angle adjustable bed having a rolling base as
set forth in claim 9 further comprising: four assist arms each
rigidly mounted onto one each of said bed support arms near said
pivotal attachment with said bed frame, each of said assist arms
having an arm slot having a width; and four assist guides each
rigidly mounted onto said bed frame near one each of said assist
arms, each of said assist guides having a guide hole having a
diameter; and four actuator assist spring mechanisms each located
between and through one each of said assist arms and one each of
said assist guides; each of said actuator assist spring mechanisms
comprising a spring shaft having a first and a second end, said
first end placed through said arm slot and said second end placed
through said guide hole, an assist spring of greater diameter than
said width of said arm slot and said diameter of said guide hole
moveably mounted onto said spring shaft between said assist guide
and said assist arm, and at least one shaft keeper on at least one
of said ends of said spring shaft, whereby said assist spring
compresses when said bed frame is placed in a nearly or fully
lowered position and thereby provides an assist force onto each of
said support arms.
11. A height and angle adjustable bed having a rolling base
comprising: a bed frame having a head, foot, right, left, and
central portion; and one or more bed support arms pivotably
attached to said bed frame; and at least one linear actuator
pivotably attached to at least one of said support arms and said
bed frame; and an assist arm mounted onto at least one of said bed
support arms near said pivotal attachment with said bed frame; and
an actuator assist spring mechanism located between said assist arm
and said bed frame, whereby said actuator assist spring mechanism
provides an assist force onto said support arm when said bed frame
is placed in a nearly or fully lowered position.
Description
[0001] This application claims priority of Provisional Patent
Application No. 60/200,902, filed May 1, 2000.
BACKGROUND OF THE INVENTION
[0002] This invention relates to height and angle adjustable beds
in general and more specifically to a bed which is typically found
in a hospital or nursing care facility and commonly known in the
medical and nursing care industries as a low height adjustable bed
or a low bed. A unique aspect of the present invention is its
movability in any direction on the floor plane while positioned at
any user desired height or angle position. This includes heights
which are substantially lower and higher than prior art industry
standard low beds and positions such as the Trendelenburg, reverse
Trendelenburg, or cardiac chair. The art of the present invention
further provides a means for reducing the mechanical actuator force
necessary for raising or lowering the bed.
[0003] Prior art height and angle adjustable low bed designs
provide front and rear lifting and support capabilities and further
provide a bed rolling capability when maintained at a specific
factory set height. (usually a fully lowered position) The
conventional low bed design provides a wide range of bed height
positioning including positioning very close to the floor. A
typical low bed design further provides one or more support arm
mechanisms pivotably attached onto the bed frame which extend near
the head or foot of the bed. The support arms help to provide the
aforesaid desirable low bed features and may contain rollers, but
not castors, which bear upon the plane of the floor near the head
or foot of the bed. Said support arms are typically controlled by
one or more mechanical or hydraulic linear actuators which cause
said support arms to pivot around each bed frame attachment point.
Unfortunately, prior art low bed designs require the support arms
to be positioned at a specific angle relative to the bed before the
bed may be rolled on the floor. That is, typically the prior art
bed must be in a fully lowered position before it engages castors
mounted on the bed frame and thereby may be rolled on the floor
plane.
[0004] The present art overcomes the aforesaid limitations of the
prior art by utilizing a unique castor base arrangement which
allows the user to adjust the height or angle of the bed to any
desired level and further roll or move the bed on the two
dimensional plane represented by the plane of the floor upon which
the bed stands. The present art bed further allows a person to lock
the bed and prevent movement in the two-dimensional floor plane at
any user desired height or angle.
[0005] Prior art beds also require an initial actuator force for
raising or lowering the bed which is substantially greater than
that of the present art. This occurs due to a mechanical
disadvantage presented to the actuators when a low bed is in a
nearly or fully lowered position. The present art bed provides an
actuator assist spring mechanism which presents an initial force to
the bed support arms when the bed is nearly or fully lowered. This
initial force helps to overcome the mechanical disadvantage
presented to the actuators and thereby reduces the force output
required from the actuators.
[0006] Accordingly, it is an object of the present invention to
provide a low bed that is movable in any direction on the plane of
the floor while positioned at a user desired height and/or
angle;
[0007] Another object of the present invention is to provide a low
bed which is stable and position lockable while providing the
aforementioned features;
[0008] A further object of the present invention is to provide a
low bed which utilizes castors instead of rollers while providing
the aforementioned features;
[0009] A still further object of the present invention is to
provide a low bed incorporating one or more actuator assist spring
mechanisms which reduce the forces required by the actuators used
to raise or lower the bed.
SUMMARY OF THE INVENTION
[0010] To accomplish the foregoing and other objects of this
invention there is provided a height and angle adjustable bed
having a rolling base. The apparatus represents an improvement in
conventional low bed designs by allowing movement in any direction
on the floor plane while the bed is positioned at a user desired
height or angle. It also provides an actuator assist spring
mechanism which reduces the linear actuator force necessary to
raise the bed. In a preferred embodiment the apparatus comprises a
bed frame having one or more pivotably attached support arms, one
or more castor bases attached to said support arms opposite said
bed frame attachment, one or more linear actuators attached between
the bed frame and said support arms, and an actuator assist spring
mechanism which reduces the linear actuator force necessary for
lifting.
[0011] The difficulty in providing a two dimensional floor plane
bed movement while also maintaining bed stability at a user desired
height/angle position is best exemplified by referring to the
operation of a typical offset castor wheel. The center mounting
axis of a castor wheel as typically used on an office chair is
offset from its mounting stud in order to ensure proper tracking
when the chair is pushed. That is, if the center axis is not
offset, the castor will not have the necessary moment arm of force
around its mounting stud axis in order to ensure positioning and
tracking of the castor in the direction of applied force. For
proper operation, the castor mounting stud must maintain a nearly
perpendicular relationship with the floor plane in order to operate
properly and avoid premature failure. If a conventional castor is
mounted directly onto the end of a low bed support arm, when the
arm is moved about its bed frame support axis, the castor stud will
not maintain a position which is perpendicular with the floor
plane. This non-perpendicular positioning will cause the castor to
jam and prohibit the castor from tracking and functioning as
expected.
[0012] The present art overcomes the aforesaid prior art
limitations by placing a pivoting castor base on a base shaft which
is mounted onto or between the bed support arms opposite the
pivotal attachment points. Each castor base comprises a castor
frame with three or more castors which are offset from the axis of
the rotating member. That is the three or more castors mounted onto
the castor base form a polygonal castor plane, such as a triangle,
square, rectangle, etc. which maintains a parallel relationship
with the floor plane when in use. A preferred embodiment utilizes
four castors in a substantially rectangular configuration with two
locking castors.
[0013] In a preferred embodiment, the aforesaid base shaft
comprises one or more shafts mounted onto a base tube supported by
the support arms. The castor base mounted on said shafts is capable
of pivoting in the same plane as the pivoting movement of the bed
support arms. The offset castors mounted onto the castor base
ensures a stable and firm wheeled base for the bed support arms
while also allowing the wheeled base to pivot near the end of the
bed support arms. Thus, as the bed support arms are lowered or
raised, the wheeled base maintains the necessary perpendicular
relationship between each castor mounting stud and the floor plane.
Since the base has pivoting castors, the bed end having the
aforesaid base is able to move easily in any direction on the two
dimensional plane of the floor. That is, each castor pivots on its
castor mounting stud in order to follow and track in the direction
of applied force.
[0014] In a preferred embodiment, one or more of the castors
contain a castor locking brake which is capable of locking the
castor both rotationally and linearly. When locked, the castors
prohibit movement of the bed on the floor plane. Nevertheless, when
the preferred embodiment includes support arm wheels on the support
arms not having the castor base, the bed may be raised or lowered
while the castor base is locked. That is, in a preferred
embodiment, the support arms near the foot of the bed contain the
aforesaid castor base and the support arms near the head of the bed
contain support arm wheels.
[0015] Another unique feature of the present invention is an
actuator assist spring mechanism. As aforesaid, conventional low
bed designs typically provide one or more bed support arms
pivotably attached to the bed frame. Typically each bed support arm
is forceably pivoted on its attachment point axis by a linear
mechanical or hydraulic actuator. The linear actuator is typically
positioned between a central portion of the support arms and the
bed frame near the head or foot portions. As the bed is lowered,
the linear actuator pivotably approaches an angle which is nearly
parallel with the support arms. This means that only a small
portion of the linear actuator force is perpendicular to the plane
of the support arms which require rotational movement. That is the
perpendicular force is represented by the equation:
F.sub.p=F.sub.l sin .THETA.
[0016] where F.sub.p is the force perpendicular to the plane of the
actuated support arms, F.sub.l is the linear actuator force, and
.THETA. is the angle between the plane formed by the support arms
and the linear actuator. Thus, when the support arms and the linear
actuator approach a parallel configuration, .THETA. becomes smaller
and approaches zero. This means that a much smaller portion of the
linear actuator force F.sub.l is available to pivot the support
arms on their axis. At a lowered position, the linear force needed
to raise the support arms can be many times the bed supporting
weight thereby necessitating use of a high force actuator.
[0017] The present art overcomes the aforementioned high force
actuator requirement by incorporating one or more actuator assist
spring mechanisms between the bed frame and each support arm. Each
assist spring compresses upon bed lowering, thus providing a
portion of the lifting force necessary when the bed is raised. The
added assist allows the present art low bed to utilize a smaller
force linear actuator than would be necessary without the assist
spring. In a preferred embodiment, each support arm has an assist
arm attached to the support arm near the pivot point with the bed
frame. The assist arm acts as the compressing arm for the assist
spring mechanism.
[0018] The aforementioned frame, support arms, castor base, and
associated components may be manufactured from a variety of
materials which provide the structural strength necessary. These
include but are not limited to materials such as iron, steel,
aluminum, titanium, and magnesium along with alloys of such, and
plastics, composites, and various woods. The castor and support arm
wheels are typically a hard or soft molded plastic or rubber
material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Numerous other objects, features and advantages of the
invention should now become apparent upon a reading of the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0020] FIG. 1 is a perspective view of the height and angle
adjustable bed in an elevated position.
[0021] FIG. 2 is a side plan view of the height and angle
adjustable bed in a lowered position.
[0022] FIG. 3 is a right side sectional plan view of an end of the
height and angle adjustable bed having a castor base in a nearly
lowered position.
[0023] FIG. 4 is a bottom side plan view of the height and angle
adjustable bed in a lowered position.
[0024] FIG. 5 is a front side plan view of the height and angle
adjustable bed in a lowered position showing a castor base.
[0025] FIG. 6 is a left side sectional plan view of an end of the
height and angle adjustable bed in an elevated position showing a
castor base.
[0026] FIG. 7 is a sectional elevation view from beneath the height
and angle adjustable bed in an elevated position looking toward an
end portion of the bed showing a castor base and support arms.
[0027] FIG. 8 is a sectional elevation view of the actuator assist
spring mechanism and support arm viewed from beneath the height and
angle adjustable bed in an elevated position.
[0028] FIG. 9 is a sectional elevation view of the actuator assist
spring mechanism and support arm viewed from beneath the height and
angle adjustable bed in a lowered position.
DETAILED DESCRIPTION
[0029] Referring now to the drawings, there is shown in FIGS. 1-9 a
height and angle adjustable bed having a rolling base 10. The
height and angle adjustable bed having a rolling base 10 is
uniquely capable of providing movement in any direction on the
floor plane while positioned at any user desired height or angle.
The bed 10 further provides a unique actuator assist spring
mechanism 40 which minimizes the linear actuator 36 force necessary
for height and angle adjustment.
[0030] The drawings show the apparatus comprising a bed frame 12
having a head, foot, top, bottom, right, left, and central portion,
one or more bed support arms 16, one or more castor bases 22, one
or more linear actuators 36, and one or more actuator assist spring
mechanisms 40. Each support arm 16 is pivotably attached 20 near a
central portion 14 of the bed frame 12 and extends outward toward
the head or foot of the bed 10. In a preferred embodiment, a
support flange 15 is attached to the bottom of said bed frame 12
and said support arm 16 is pivotably held by said flange 15 with a
support shaft 21. The support shaft 21 is typically a bolt placed
through a flange hole 13 and an arm hole 27. In alternative
embodiments, the support shaft 12 may be any other shaft form which
allows pivoting of the support arm 16. Alternative embodiments may
forego use of said flange 15 and pivotably mount said support arm
16 directly onto the bed frame 12.
[0031] In a preferred embodiment, a pair of bed support arms 16 are
used near each end of the bed 10 for a total of four. That is, a
support arm 16 is placed on each side of the bed 10 and directed
toward each end for optimum bed 10 stability. The preferred
embodiment ties each pair of support arms 16 together with a
crossarm 23 and a base tube 18. Each crossarm 23 and base tube 18
are attached between the pair of support arms 16 by welding each in
place. The crossarm 23 and base tube 18 may also be attached by any
other attachment means such as bolts, rivets, or adhesives.
Alternative embodiments may use a single bed support arm 16 on one
or both ends which is centrally and pivotably mounted and also of
sufficient structural strength to support the bed 10.
[0032] The pivoting of each support arm 16 pair on the support
shafts 21 allows the bed 10 to be raised or tilted as desired. In a
preferred embodiment, a linear actuator 36 forceably pivots each
pair of support arms 16. The linear actuator 36 is typically a
hydraulic cylinder or motorized mechanical linear force actuator.
In a preferred embodiment, a first end of the linear actuator 36 is
pivotably attached onto the crossarm 23 and a second end of the
linear actuator 36 is pivotably attached onto the bed frame 12 near
an end of the bed 10. That is, near the head or foot of the bed 10
which lies above the pivoting support arms 16.
[0033] In a preferred embodiment, each support arm 16, has an
assist arm 17 integrally attached near the pivotable attachment
point 20 near the central portion 14 of the bed frame 12. The
assist arm 17 is an extension of the support arm 16 and positioned
at a generally perpendicular angle relative to the support arm 16
in a preferred embodiment. Alternative embodiments may incorporate
the assist arm 17 parallel with and as an integral part of the
support arm 16. The assist arm 17 serves as a compressor for the
actuator assist spring mechanism 40 when the bed 10 is nearly or
fully lowered. As aforesaid, the actuator assist spring mechanism
40 serves to provide an initial pivoting force on the support arms
16 when the bed 10 is near or at a fully lowered position. In the
preferred embodiment, the actuator assist spring mechanism 40 is
mounted between the assist arm 17 and an assist guide 50 mounted
onto the bed frame 12. Alternative embodiments may forego use of
the assist guide 50 by incorporating its function within the bed
frame 12. This unique feature minimizes the initial force required
by the linear actuator 36 to raise the bed 10. That is, due to the
aforesaid mechanical disadvantage which each linear actuator 36 has
as it becomes more closely parallel and aligned with the support
arms 16, the force required by each linear actuator 36 to raise the
bed 10 increases toward infinity. Thus, the actuator assist spring
mechanism 40 provides enough force onto the assist arm 17 in order
to assist pivoting of the support arms 16 into an angle relative to
the linear actuator 36 which substantially reduces the mechanical
disadvantage of the linear actuator 36. This unique feature
substantially reduces the size, weight, and output force
requirement of the linear actuator 36.
[0034] The actuator assist spring mechanism 40 comprises a spring
shaft 42, an assist spring 44 and one or more shaft keepers 46. The
spring shaft 42 mounts through an arm slot 25 in the assist arm 17
and a guide hole 52 in the assist guide 50. In a preferred
embodiment, onto the ends of each spring shaft 42 is placed a shaft
keeper 46, such as an enlarged end, a nut and washer, C-clip, etc.
to ensure that the spring shaft 42 does not withdraw from the arm
slot 25 or the guide hole 52. Alternative embodiments may place the
shaft keeper(s) 46 at only one end or forego use of the shaft
keeper(s) 46 completely and hold the spring shaft 42 by other means
such as pins, mating grooves, or a frictional fit without departing
from the scope of the present art. The assist spring 44 is
typically a coil spring which is placed onto said spring shaft 42
between said arm slot 25 and guide hole 52 and is larger in
diameter than the width of said slot 25 or the diameter of said
hole 52. Thus when the bed 10 is lowered, the assist arm 17
compresses the assist spring 44 against the assist guide 50,
thereby providing an initial force on each support arm 16 during
bed raising.
[0035] Alternative embodiments may place the assist arm 17 at other
angles relative to the support arms 16 or incorporate the assist
arm 17 together with the support arm 16. The aforesaid Alternative
embodiments will not depart from the scope and spirit of the
present invention provided that the actuator assist spring 44 is
compressed and allowed to assist raising movement of the support
arms 16 when the bed 10 is in a nearly fully lowered position.
Further alternative embodiments may incorporate other types of
assist springs such as leaf springs or torsion bars without
departing from the spirit of the present invention.
[0036] As aforesaid, onto the support arms 16 opposite said pivotal
attachment 20 is mounted a base tube 18 onto which is pivotably
mounted a castor base 22 or one or more support arm wheels 19. The
base tube 18 is of generally tubular form and rigidly attached
between said support arms 16. The castor base 22 comprises a castor
frame 24 pivotably mounted and attached onto the base tube 18 with
a base shaft 26. The base shaft 26 typically comprises a bolt
placed through a frame ear 58 on said castor base 22 and mated with
a threaded insert mounted into the base tube 18. In a preferred
embodiment, the aforementioned form of base shaft 26 is used on
each support arm 16. Each support arm wheel 19 is also held with a
base shaft 26 when used. Alternative embodiments may forego use of
the base tube 18 and mount said base shafts 26 directly onto one or
more support arms 16.
[0037] The castor frame 24 may form any planar polygonal form but
defines a substantially rectangular "H" form in the preferred
embodiment. In the preferred embodiment, the castor frame 24
comprises a substantially "H" shaped member having two frame arms
56 rigidly connected in perpendicular relation via a frame support
angle 60. Each frame arm 56 also has a frame ear 58 rigidly
connected and extending downward from near the midpoint of each
frame arm 56. As aforesaid, each frame ear 58 is pivotably held
onto said base tube 18 with a base shaft 26, typically a bolt,
through an ear hole 59 in each frame ear 58. The aforementioned
shaft 26 and ear 58 combination thereby pivotably holds the entire
castor base 22. Alternative embodiments may pivotably hold the
castor frame 24 onto each support arm 16 with a variety of methods
including but not limited to shaft and bearing assemblies, ball
joint arrangements, flexible couplings, or torsion bars, provided
each is capable of supporting the working load of the bed 10.
Alternative embodiments may also forego utilization of the frame
support angle 60 without departing from the spirit of the present
art. That is, each frame arm 56 may be allowed to pivot
independently upon its own base shaft 26.
[0038] Onto the castor frame 24 is mounted at least three castors
28 with the preferred embodiment having four castors 28, one
mounted at each end of the frame arms 56, that is, at the edges of
the "H" form. In a preferred embodiment, the castor mounting stud
30 is rigidly held in an arm hole 61 within each frame arm 56.
Alternative embodiments may weld or rigidly affix the castor
mounting stud 30 to the frame arm 56 without departing from the
spirit of the present invention. Further alternative embodiments
may allow the castor mounting stud 30 to rotate within the arm
hole, provided the user does not require rotational locking of the
castor mounting stud 30. In a preferred embodiment, two of the
aforesaid castors 28 have an integral castor locking brake 32 which
at the user's option may lock the castor 28 to prevent castor wheel
34 movement and also prevent rotational movement on the castor
mounting stud 30. Alternative embodiments may provide one or more
integral castor locking brakes 32 without departing from the spirit
of the present invention.
[0039] A unique feature of the present invention in all of its
embodiments is the ability of the castor base 22 to provide a
pivoting but structurally stable planar polygonal base which
includes integrally mounted castors 28. The pivoting feature
relative to the support arms 16 ensures a substantially
perpendicular relation between the castor mounting stud 30 and the
plane of the floor, thereby further ensuring optimum castor
operation. Attachment of the mounting stud 30 near or onto the ends
of the frame arms 56 provides maximum separation between the
castors 28, thereby providing the most stable castor base.
[0040] As aforesaid, a castor 28 will not function properly if its
mounting stud 30 deviates appreciably from a perpendicular
relationship with the plane of the floor onto which it rolls. In
light of the aforementioned requirement for proper operation, the
castor base 22 with its attached castors 28 may be pivotably
attached to the support arm 16 ends with any method or apparatus
that allows the rigid base 22 to pivot. Again, this includes but is
not limited to shaft and bearing assemblies, ball joint
arrangements, flexible couplings, or torsion bars, provided each is
capable of supporting the working load of the bed 10.
[0041] The preferred embodiment places a castor base 22 on a pair
end of support arms 16 and a pair of support arm wheels 19 on the
opposite pair end of support arms 16. This preferred embodiment
allows the user to move the bed 10 end, generally the foot, having
the castor base in any direction on the floor plane. The support
arm 16 ends having support arm wheels 19 thereafter follow the
directional movement of the castor base 22 in an arcing or linear
motion on the floor plane.
[0042] Alternative embodiments may utilize a castor base 22 at the
ends of each support arm 16 pair. This alternative provides further
freedom of movement on the floor plane by allowing both the head
and foot of the bed 10 to be moved in any direction on the floor
plane. Nevertheless, the aforesaid alternative embodiment presents
further complexities related to castor 28 locking and braking. That
is, with the preferred embodiment, locking of one castor 28 on the
castor base 22 fixes the bed 10 into position on the floor plane.
By design, the support arm wheels 19 cannot move laterally relative
to the head-foot bed 10 axis, i.e. left to right, and a locked
castor 28 prohibits any floor plane movement of the castor base 22,
including linear movement in the head-foot bed 10 axis. If a castor
base 22 is substituted for the support arm wheels 19, complete bed
10 position locking requires that at lease one castor locking brake
32 on each castor base 22 be activated. Furthermore, this
alternative embodiment prohibits bed 10 height adjustment when both
castor bases 22 are locked.
[0043] In operation, the user causes the linear actuator to raise
or lower the support arm 16 at each end for the desired bed 10
height and angle. When the bed 10 requires movement, force is
applied in the desired movement direction on the castor base 22 end
of the bed 12. Each castor 28 then rotates upon its mounting stud
30 in order to align each castor wheel 34 with the direction of
desired travel and the castor wheel 34 begins to rotate. If
equipped with a pair of support arm wheels 19, said wheels follow
and track the castor base 22 movement. When placed at a desired
location, the castors 28 may be locked in all axis via the action
of the integral castor locking brake 32. This prevents the castor
base 22 from moving in any direction and thereby secures the bed 10
in a fixed location. Moreover, since the support arm wheels 19 may
rotate when the castor base 22 is locked, the bed 10 may be raised
or lowered when in a castor 28 is in a locked position.
[0044] From the foregoing description, those skilled in the art
will appreciate that all objects of the present invention are
realized. A height and angle adjustable bed having a rolling base
is shown and described. The apparatus allows bed movement on the
plane of the floor when adjusted to any desired height. In a
preferred embodiment, the apparatus also allows bed height and
angle adjustment when locked into position. Further innovative
concept is provided by utilization of an actuator assist spring
mechanism in conjunction with the bed support arms. The actuator
assist spring mechanism reduces the required linear actuator force
output.
[0045] In view of the above, it will be seen that the objects and
features of this invention are achieved and other advantageous
results attained. Having described the invention in detail, those
skilled in the art will appreciate that modifications may be made
of the invention without departing from its spirit. Therefore, it
is not intended that the scope of the invention be limited to the
specific embodiments illustrated and described. Rather it is
intended that the scope of this invention be determined by the
appended claims and their equivalents.
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