Abstrict 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.
Claims What is claimed is:
1. A low 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
two or more bed support arms pivotably attached to said bed frame
in a non-translatory manner; and
at least one mechanical linear force 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 capable of pivoting independent
of movement of said bed support arms; 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. A low 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;
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; and
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 low height and angle adjustable bed having a rolling base
comprising:
a bed frame having a head, foot, right, left, and central portion;
and
two or more bed support arms pivotably attached to said bed frame;
and
at least one mechanical linear force 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.
12. A method of allowing a low height and angle adjustable bed
to move in any direction on a floor plane when positioned at any
height or angle, the steps comprising:
forming a bed frame having a head, foot, right, left, and central
portion; and
pivotably attaching two or more bed support arms to said bed frame
with two or more support shafts whereby said support shafts do not
move translatory upon said bed frame; and
mounting at least one mechanical linear force actuator between
at least one of said support arms and said bed frame; and
pivotably mounting at least one castor base to at least one of
said support arms near the floor plane whereby said castor base
pivots independent of movement of said bed support arms; and
mounting three or more castors in a polygonal form onto said castor
base, whereby said castors of said polygonal form rest upon the
floor plane and maintain said castor base stable yet moveable in
the floor plane independent of the height or angle of said bed frame.
13. The method of allowing a low height and angle adjustable bed
to move in any direction on a floor plane when positioned at any
height or angle as set forth in claim 12 the steps further comprising:
forming an assist arm onto at least one of said bed support arms
near said support shaft; and
placing an actuator assist spring mechanism between said assist
arm and said bed frame; and
compressing said assist spring mechanism by lowering said bed to
a nearly fully lowered position and thereby placing a force between
said assist arm and said bed frame; and
decompressing said assist spring mechanism by utilizing the force
of said assist spring mechanism between said assist arm and said
bed frame and actuating said mechanical linear force actuator thereby
raising said bed from said nearly fully lowered position.
14. A method of allowing a height and angle adjustable bed having
a mechanical linear force actuator to raise, the steps comprising:
forming a bed frame having a head, foot, right, left, and central
portion; and
pivotably attaching two or more bed support arms to said bed frame
with two or more support shafts; and
mounting at least one mechanical linear force actuator between
at least one of said support arms and said bed frame; and
forming an assist arm onto at least one of said bed support arms
near said support shaft; and
placing an actuator assist spring mechanism between said assist
arm and said bed frame; and
compressing said assist spring mechanism by lowering said bed to
a nearly fully lowered position and thereby placing a force between
said assist arm and said bed frame; and
decompressing said assist spring mechanism by utilizing the force
of said assist spring mechanism between said assist arm and said
bed frame and actuating said mechanical linear force actuator thereby
raising said bed from said nearly fully lowered position.
Description BACKGROUND OF THE INVENTION
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.
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.
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.
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.
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;
Another object of the present invention is to provide a low bed
which is stable and position lockable while providing the aforementioned
features;
A further object of the present invention is to provide a low bed
which utilizes castors instead of rollers while providing the aforementioned
features;
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
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.
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.
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.
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.
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.
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:
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.
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.
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
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:
FIG. 1 is a perspective view of the height and angle adjustable
bed in an elevated position.
FIG. 2 is a side plan view of the height and angle adjustable bed
in a lowered position.
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.
FIG. 4 is a bottom side plan view of the height and angle adjustable
bed in a lowered position.
FIG. 5 is a front side plan view of the height and angle adjustable
bed in a lowered position showing a castor base.
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.
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.
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.
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
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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. |