Note: Descriptions are shown in the official language in which they were submitted.
CA 02501419 2005-03-18
LATERALLY ADJUSTABLE ARMREST ASSEMBLY
FIELD OF THE INVENTION
[0001] The present invention relates generally to laterally adjustable armrest
assemblies.
In particular, the present invention relates to laterally adjustable armrest
assemblies for bariatric
chairs.
BACKGROUND OF THE INVENTION
[0002] One of the most critical seating dimensions associated with bariatric
chairs is the
seat width. Since bariatric patients typically accumulate the majority of
their weight around their
lower torso and upper thighs, the seat width determines if the bulk of the
bariatric patient will
properly fit the chair. Similarly, when a bariatric chair design incorporates
armrests, the limiting
dimension that determines the width-wise fit of the chair to the bariatric
patient becomes the
distance between the insides of the armrests, which is usually equivalent to
or close to the true
width of the seating surface. When dealing with shower and commode chairs,
which are
generally communal among the residents of a bariatric healthcare facility, a
seat width that may
be functional for one bariatric patient may be too big or too small for
another. The typical
solution would be to accommodate the largest bariatric and sacrifice a
comfortable armrest
position for smaller patients, or conversely, to accommodate the smaller
patients and remove the
armrest for any especially large bariatric patients. Although accommodating
bariatric patients in
chairs that do not adequately fit them may be economically practical for a
facility, the chair
becomes uncomfortable for individual users as well, potential safety issues
are created. By not
having the full and proper use of the armrests to steady themselves, the
bariatric occupant of the
chair will feel laterally unsupported and instable, which creates a
psychological discomfort and
anxiety. However, in the case where an occupant begins to fall over the edge
of the seat there
are no restraints or supports for the patient to steady them self with to
prevent the fall.
[0003] Another challenge associated with accommodating especially wide seats
on
bariatric shower and commode chairs is caregiver usability in areas where
maneuvering space is
limited. That is the ability for the caregiver to push the width of the chair
through doorways and
CA 02501419 2005-03-18
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other narrow openings, as well as manipulating the chair in and around tight
spaces commonly
found in showering areas and washrooms in healthcare facilities. The actual
source of the
physical interference caused by extra wide seats can usually be attributed to
the external width
across the armrests. Since armrests are typically mounted on the outside of
the seat width, to
ensure proper arm positioning, this mounting position places them at the
widest section of the
chair and makes them the most likely source of interference. For this reason
many shower and
commode chairs for bariatric patients have either removable armrests or
armrests that are
mounted within the width of the seating surface, which effectively reduces the
seat width.
[0004] The width between the armrests also has an effect as to how easy shower
and
commode chairs are to use as well as how comfortable they are to sit in. For
example, when
bathing a bariatric patient it is common to have the excess flesh from around
the thighs fill the
seat width up to the front and rear armrest support members. When this happens
it becomes
difficult for the caregiver to wash these areas hidden by the armrest hardware
because of the
limited access to the occupant. Also, by not having adequate clearance between
the chair
hardware and the occupant, bariatric patients cannot be transferred to and
from the chair as
casily. Since most bariatric patients are heavier than what is typically
allowed for manual
transfers, caregivers rely a great deal on being able to use motorized or
hydraulic transfer lifts
that utilize full body slings to support the body.
[0005] These lifting slings need to be wrapped around strategic areas of the
body in order
to function properly and safely. In non-bariatric cases the occupant of the
chair could easily
reposition themselves or be repositioned by the caregiver to expose any
inaccessible areas that
need washing or to allow transfer lift body slings to be fitted. However when
dealing with
bariatrics patients, repositioning the person is not easily achieved due to
their extreme size and
weight. In most cases the bariatric shower chair would have provisions for
swing-away, swing-
up, flip-down, or removable armrests which would allow the caregiver to access
any areas that
were being blocked by the armrests. The cost of this solution is that the
armrests become
unusable for that duration, making the chair uncomfortable and potentially
unsafe for the
bariatric patient to sit in since they would be required to support the entire
weight of their own
arm as well as loose any form lateral support to stabilized themselves.
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[0006] When a bariatric chair is used for commode activities it is a common
desire and
necessity for most people, and especially men, to relax and widen their legs
in order to
comfortably void themselves. If the commode chair is correctly sized when the
bariatric patient
is seated normally, opening their legs becomes impossible because the front
vertical supports of
the armrests will interfere with theirs knees and will prevent the occupant
from moving their
thighs outward. Due to the nature of most commode chair seats, with the
commode pan reservoir
positioned to match the regular seated position, the person cannot reposition
themselves
sufficiently forward to spread their legs without creating a misalignment with
the commode
reservoir. If the commode chair has provisions for swing-away, swing-up, flip-
down, or
removable armrests the occupant's legs can be accommodated, but again at the
expense of
loosing the use, security, and comfort of the armrests.
SUMMARY OF THE INVENTION
[0007] According to an aspect of the present invention, there is provides an
adjustable
armrest assembly for a chair, the armrest assembly comprising: a stationary
linkage which is
connectable to the chair; an armrest member for supporting an arm of an
individual when seated
in the chair; a coupling member effecting coupling of the armrest member to
the stationary
linkage, the coupling member permitting travel of the armrest member relative
to the stationary
linkage; and, a locking element configured for acting on the coupling member
to effect locking
of the armrest member in any one of at least three indexed positions relative
to the stationary
linkage.
[0008] According to another aspect of the present invention there is provided
an
adjustable armrest assembly wherein the permitted travel of the armrest member
relative to the
stationary linkage is along an arc-like path.
[0009] According to another aspect of the present invention there is provided
an
adjustable armrest assembly, wherein the coupling member is a swivel linkage.
[0010] According to another aspect of the present invention there is provided
an
adjustable armrest assembly, wherein the swivel linkage comprises a stationary
linkage coupling
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portion and an armrest coupling portion, the stationary linkage coupling
portion being offset
from the armrest coupling portion, the stationary linkage coupling portion
further being rotatably
coupled to the stationary linkage, thereby permitting rotatable movement of
the swivel linkage
relative to the stationary linkage, and the armrest coupling portion being
rotatably coupled to the
armrest member, thereby permitting rotatable movement of the swivel linkage
relative to the
armrest member.
[0011 ] According to another aspect of the present invention there is provided
an
adjustable armrest assembly, wherein the armrest member includes an armrest
coupling linkage
for effecting the rotatable coupling to the swivel linkage, and wherein the
locking element
includes a detent pin which is biased to interfere with the relative
rotational movement between
the swivel linkage and the armrest coupling linkage, such that the locking in
an indexed position
is effected by the detent pin being positioned in both a swivel linkage hole
provided in the swivel
linkage and in a respective armrest coupling hole provided in the armrest
coupling linkage, the
detent pin becoming so positioned when the swivel linkage hole and the
respective armrest
coupling linkage hole are disposed in an overlapping relationship, the swivel
linkage hole and
the respective armrest coupling linkage hole becoming so disposed upon
relative rotational
movement between the swivel linkage and the armrest coupling linkage.
[0012] According to another aspect of the present invention there is provided
an
adjustable armrest assembly, wherein the locking element is coupled to one of
the swivel linkage
and the armrest coupling linkage.
[0013] According to another aspect of the present invention there is provided
an
adjustable armrest assembly, further comprising a threaded handwheel
configured for acting on
the coupling member and effecting locking of the armrest member in positions
other than the at
least three indexed positions.
[0014) According to another aspect of the present invention there is provided
an
adjustable armrest assembly for a chair, the armrest assembly comprising: a
stationary linkage
configured for coupling to the chair; an armrest member for supporting an arm
or an individual
when seated in the chair; at least two swivel linkages coupling the armrest
member to the
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stationary linkage, each of the at least two swivel linkages including a
respective stationary
linkage coupling portion rotatably coupled to the stationary linkage for
rotation about a
respective swivel linkage-stationary linkage axis, and also including a
respective armrest
member coupling portion rotatably coupled to the armrest member for rotation
about a respective
swivel linkage -armrest member axis; wherein each of the at least two swivel
linkages is
characterized by a respective horizontal offset distance which is defined as
the horizontal
distance between the respective swivel linkage-stationary linkage axis and the
respective swivel
linkage-armrest member axis; and wherein the at least two swivel linkages
include at least a first
terminal swivel linkage and a second terminal swivel linkage; and wherein
either of the first or
second terminal swivel linkages has a respective horizontal offset distance
which is at least 1.2
times longer than the respective horizontal offset of the other of the at
least two swivel linkages.
[0015] According to another aspect of the present invention there is provided
an
adjustable armrest assembly, wherein either of the first or second terminal
swivel linkages is a
front swivel linkage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Preferred embodiments of the present invention are described below with
reference to the accompanying drawings in which:
[0017] Figure 1 is a front perspective view of a bariatric chair having an
armrest
assembly according to an embodiment of the present invention;
[0018] Figure 2 is a side elevation view of a bariatric chair having an
armrest assembly
according to an embodiment of the present invention;
[0019] Figure 3 is a front elevation view of bariatric chair having an armrest
assembly
according to an embodiment of the present invention;
[0020] Figure 4 is a rear elevation view of bariatric chair having an armrest
assembly
according to an embodiment of the present invention;
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[0021 J Figure S is a top plan view of bariatric chair having an armrest
assembly
according to an embodiment of the present invention;
[0022] Figure 6 is a perspective view of an armrest assembly of the chair
according to an
embodiment of the present invention;
[0023] Figure 7 is an exploded perspective view of an armrest assembly of the
chair
according to an embodiment of the present invention;
[0024] Figure 8 is a plan view of an armrest assembly of the chair in a first
narrow
position according to an embodiment of the present invention;
[0025] Figure 9 is a plan view of an armrest assembly of the chair in a wide
position
according to an embodiment of the present invention;
[0026] Figure 10 is a plan view of an armrest assembly of the chair in a
second narrow
position according to an embodiment of the present invention;
[0027] Figure 11 is a cross-sectional side elevation view of an armrest
assembly of the
chair according to an embodiment of the present invention, illustrating a hand
wheel lock in an
engaged position; and
[0028] Figure 12 is a cross-sectional side view of the armrest of Figure 11,
illustrating
the hand wheel locked in a disengaged position.
[0029] Figure 13 is a top perspective view of a backrest of a chair according
to an
embodiment of the present invention;
[0030] Figure 14 is a side elevation view of a backrest of a chair according
to an
embodiment of the present invention;
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[0031] Figure 15 is an exploded view of a seat of a chair according to an
embodiment of
the present invention;
[0032] Figure 16 is a front perspective view of a chair frame of a chair
according to an
embodiment of the present invention;
[0033] Figure 17 is an illustration of an extendible/retractable support
member of a chair
according to an embodiment of the present invention;
[0034] Figures 18 and 19 are, respectively, the side elevation view and a
front elevation
view of the combined seat and backrest of a chair according to an embodiment
of the present
invention, illustrating the relationship between various components of the
seat and backrest;
[0035] Figures 20A, 20B, 20C, and 20D are, respectively, a side elevation
view, a top
plan view, a further side elevation view, and yet a further side elevation
view, of the combined
seat and backrest of a chair according to an embodiment of the present
invention, further
illustrating the spatial relationship between the components of the chair and
the backrest;
[0036] Figures 21, 22, 23 and 24 are, respectively, a side elevation view, a
top plan view,
a further side elevation view, and a front elevation view of the combined seat
and backrest of a
chair according to an embodiment of the present invention, illustrating
various points of
reference to define dimensions of the backrest;
[0037] Figures 25 and 26 are, respectively, a side elevation view and a top
plan view of a
combined seat and backrest of a chair according to an embodiment of the
present invention,
illustrating the relationship between various components of the seat and
backrest to assist in
defining the cross-sectional area of a recess provided by the chair;
[0038] Figures 27, 28 and 29 are, respectively, a side elevation view, a top
plan view, and
a further side elevation view of a combined seat and backrest of a chair
according to an
embodiment of the present invention, illustrating the relationship between
various components of
the seat and back rest to assist in defining the depth of a recess provided by
the chair;
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[0039] Figures 30, 31 and 32 are, respectively, a side elevation view, a top
plane view,
and a further side elevation view of a combined seat and backrest of a chair
according to an
embodiment of the present invention, illustrating the relationship between
various components of
the seat and the backrest in order to assist in defining a depth of a recess
provided by the chair;
[0040] Figures 33 and 34 are, respectively, a side elevation view and a top
plan view of a
combined seat and backrest of a chair according to an embodiment of the
present invention,
illustrating the relationship between various components of the seat and the
backrest in order to
assist in defining the height of a recess provided by the chair;
[0041] Figures 35, 36 and 37 are, respectively, a front elevation view, a top
plan view,
and a side elevation view of a combined seat and backrest of a chair according
to an embodiment
of the present invention, illustrating the relationship between various
components of the seat and
the backrest in order to assist in defining the spatial relationship between
such components;
[0042] Figures 38 and 39 are side elevation views of a combined seat and
backrest of a
chair according to an embodiment of the present invention, illustrating the
relationship between
various components of the seat and the backrest in order to assist in defining
a depth of a recess
provided along a width segment of the chair;
[0043] Figure 40 is a side elevation view of a combined seat and backrest of a
chair
according to an embodiment of the present invention, illustrating the
relationship between
various components of the seat and the backrest in order to assist in defining
a height of a recess
provided along a width segment of the chair;
[0044] Figure 41 is a side elevation view of a combined seat and backrest of a
chair
according to an embodiment of the present invention, illustrating the
relationship between
various components of the seat and the backrest in order to assist in defining
a cross-sectional
area of a recess extending along a width segment of the chair; and
[0045] Figure 42 is a bottom plan view of a seating element of a chair
according to an
embodiment of the present invention.
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9
DETAILED DESCRIPTION OF THE INVENTION
[0046] Refernng to Figures 6 and 7, an adjustable armrest assembly 500 for the
bariatric
chair 10 is illustrated according to an embodiment of the present invention.
The armrest
assembly 500 comprises an armrest member 522 for supporting an arm of an
individual when
seated in the chair 10, and a coupling member 555 for coupling the armrest
member 522 to an
armrest side (550a or 550b) of the chair 10. The coupling member 555
facilitates lateral
movement of the armrest member 522 relative to the chair 10 between at least
three indexed
armrest positions. The armrest assembly 500 also includes a locking mechanism
900 configured
for acting on the coupling member 555 so as to effect locking of the armrest
522 in any one of
the at least three indexed locked positions.
[0047] It is understood that, when the armrest 522 becomes locked in one of
the at least
three indexed locked positions, the armrest 522 may or may not be completely
stationary, and if
not completely stationary, then the armrest 522 may move (ie. travel) a minor
distance owing to
the fact that interacting components which effect locking of the armrest 522
in the one of the at
least three indexed locking positions are configured with some play between
them.
[0048] It is also understood that the at least three indexed armrest positions
are
distinguished from one another by the fact that the spatial disposition of the
armrest 522 when
locked in any one of the at least three indexed positions is never identical
to the spatial
disposition of the armrest 522 when locked in any of the other of the at least
three indexed
positions. However, it is also understood that the spatial disposition of a
first portion of the
armrest, when the armrest 522 is disposed in a first spatial position, may
overlap (ie. occupy the
same space) with the spatial disposition of a second portion of the armrest
522, when the armrest
522 is disposed in a second spatial position. For example, referring to
Figures 8 and 10 which
illustrate the armrest 522 in respective forward narrow and rearward narrow
positions, portion
'A' of the armrest 522 is shown moving laterally and rearwardly as the armrest
522 moves from
the forward narrow position (Figure 8) to the wide rearward narrow position
(Figure 10). When
the armrest 522 is in the forward narrow position, portion 'B' of the armrest
522 is disposed in
(occupies) a certain space, relative to the chair 10. When the armrest 522 is
in the rearward
CA 02501419 2005-03-18
narrow position, portion 'A' of the armrest 522 is disposed in this same space
(ie. the space
occupied by portion 'B' when the armrest 522 is disposed in the forward narrow
position). In
this respect, the spatial disposition of portion 'A', when the armrest 522 is
lateral in a first
position, overlaps with the spatial disposition of portion 'B' when the
armrest 522 is lateral in a
second position.
[0049] With particular reference to the case where the armrest 522 is not
completely
stationary when locked in at least one of the at least three indexed
positions, it is also understood
that the at least three indexed armrest positions are distinguished from one
another by the fact
that, where there is some movement of the armrest 522 when in one of the at
least one of the at
least three indexed positions, the various spatial dispositions of the armrest
522 within the scope
of travel of the armrest 522 in such indexed position are never identical to
the spatial disposition
or dispositions (in the case where there is minor movement of the armrest 522
in another indexed
position) of the armrest in any of the other of the at least three indexed
positions (although a
spatial disposition of a portion of the armrest 522, when the armrest 522 is
disposed in a first
spatial position, may overlap with a spatial disposition of a second portion
of the armrest 522,
when the armrest 522 is disposed in a second spatial position).
[0050] In the embodiment illustrated in Figure 1, the chair 10 is configured
with an
armrest assembly 500 on each armrest side 550a, 550b of the chair 10. Figures
6 and 7 illustrate
an armrest assembly 500 of one side 500a of the chair 10. The armrest assembly
500 for the
opposite side 550b of the chair 10 is a mirror image of the armrest assembly
of the side 550a of
the chair 10.
[0051] The armrest assembly 550 can form an integral part of the chair 10.
Alternately,
the armrest assembly 550 may be configured for connection to the chair. In the
embodiment
illustrated in Figure 1, two armrest assemblies 500 are provided, and each is
connected to a
respective one of the opposite armrest sides 550x, 550b of the chair 10.
[0052] The armrest member 522 may include any padded armrest known to those
skilled
in the art. For example, the armrest member 522 may include a molded plastic
material. As a
further example, the armrest member 522 is constructed of self skinning
polyurethane foam
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molded over a plywood inner cores and has two internally embedded threaded
steel inserts used
for fastening. It will be apparent to those skilled in the art that any
armrest that can support an
arm of an individual when seated in the chair may be employed.
[0053] In the illustrated embodiment, the coupling member 555, which permits
lateral
movement of the armrest member 522 relative to the chair 510, is a four-bar
linkage assembly as
is known to those skilled in the art. The four-bar linkage assembly comprises
a stationary
linkage 565, swivel linkages 570, 670, and an armrest coupling linkage 575.
[0054] The stationary linkage 565 is either configured for coupling to an
armrest side
500a (or SOOb) of the chair 10, or is formed as an integral part of the chair
10 and is disposed at
an armrest side 500a (or 500b) of the chair 10. In the illustrated embodiment,
the stationary
linkage 565 is integral to the chair 10, and the stationary linkage 575 forms
a portion of each of
the upper rails 84a, 84b (as each side 500a, 500b includes an armrest assembly
500).
[0055] The swivel linkages 570 and 670 are provided to effect coupling of the
armrest
coupling linkage 575 to the stationary linkage 565 while facilitating lateral
movement of the
armrest coupling linkage 575 relative to the stationary linkage 565. Each of
the swivel linkages
570, 670 is rotatably connected to the stationary linkage 565 in spaced-apart
relationship to one
another along a length of the stationary linkage 565 such that the swivel
linkage 570 is rotatably
connected to the stationary linkage 565 closer to the front of the chair 10
and the swivel linkage
670 is rotatably connected to the stationary linkage 565 closer to the back of
the chair 10.
[0056] Each of the swivel linkages 570, 670 is also rotatably connected to the
armrest
coupling linkage 575 in spaced apart relationship to one another along a
length of the armrest
coupling linkage 575, such that the swivel linkage 570 is rotatably connected
to the armrest
coupling linkage 575 closer to the front of the chair and the swivel linkage
670 is rotatably
connected to the armrest coupling linkage 575 closer to the back of the chair
10. The connection
of each of the swivel linkages 570, 670 to the armrest coupling linkage 575 is
offset relative to
the respective connection of each of the swivel linkages 570, 670 to the
stationary linkage 565.
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[0057] The armrest coupling linkage 575 is connected to the armrest member
522, such
as by screw 521.
[0058] The stationary linkage 565 includes an elongated frame member 510
having a
front joint portion 577 and a back joint portion 579, such that the front
joint portion 577 is
positioned closer to the front of the chair 10 and the back joint portion 579
is positioned closer to
the back of the chair 10. Each of the joint portions 577, 579 preferably
includes a respective one
of offset posts S 11 a, 511 b. Each of the posts 511 a, 511 b extends
laterally from the frame
member 510 and includes a respective one of sockets 512a, S 12b. Each of the
sockets 512a,
512b is in the form of a tube segment defining a throughbore 5124 having a
substantially circular
cross-section along its length between respective ends of the tube segment.
The respective ends
of the tube segment have a vertical axis 5251 oriented orthogonally to the
longitudinal axis of the
respective offset post 51 la, S l 1b (Figure 7).
[0059] The swivel linkage 570 includes a stationary linkage joint portion 525
and an
armrest joint portion 516. The stationary linkage joint portion 525 is offset
from the armrest
joint portion 516 and joined to the armrest joint portion 516 by a laterally
extending connector
517. The stationary linkage portion 525 is rotatably connected to the socket S
12a of the
stationary linkage 565, thereby facilitating rotatable movement of the swivel
linkage 570 about
the axis passing through the socket S 12a.
[0060] The stationary joint portion 525 includes upper and lower concentric
cylindrical
segments 5252, 5254. The diameter of the upper segment 5252 is greater than
the diameter of
the lower segment 5254. The segment 5254 is received within and rotatably
engaged to the
socket S 12a. The lower segment 5254 is joined to the upper segment 5252 by a
surface 5256
extending peripherally and outwardly from the lower segment 5254. The surface
5256 is seated
upon a shoulder portion 5122 of the socket 512 (and thereby effecting vertical
support of the
surface 5256 by the shoulder portion S 122) when the tube segment 5252 is
received within the
socket 512a. In this respect, the stationary joint portion 525 is rotatably
connected to the socket
512a and is configured for rotation relative to the socket S 12a about the
vertical axis 5251.
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[0061] A locking mechanism 701 is provided to prevent disengagement of the
stationary
joint portion 525 from the socket 512a by limiting upwards displacement of the
stationary joint
portion 525 relative to the socket 512a. When the locking mechanism 701 is in
the operative
condition, the stationary joint portion 525 is secured to the socket 512a.
When the locking
mechanism 701 is in an inoperative condition, the stationary joint portion 525
is unsecured
relative to the socket 512a. The stationary joint portion 525 is secured to
the socket 512a by
effecting interference of upwards displacement of the stationary joint portion
525 relative to the
socket 512a. Such interference action is accommodated by having the stationary
joint portion
525 extend through and below the socket 512a, and having a lower portion 5258
of the lower
segment 5254 of the stationary joint portion 525 extending below the socket
512a coupled to a
moveable detent 703 which selectively abuts against a lower end of the socket
512a if an attempt
is made to pull the stationary joint portion 525 out of the socket 512a.
[0062] In order for the stationary joint portion 525 to assume an unsecured
condition
relative to the socket 512a, the detent 703 is configured so as to be capable
of receding to a
position which does not interfere with the upwards displacement of the
stationary joint portion
525 relative to the socket 512a. When the detent 703 is so receded, the
locking mechanism 701
is in the inoperative condition. When the detent 703 is in the outwardly
extended position,
interfering with the upwards displacement as described above, the locking
mechanism 701 is in
the operative condition.
[0063] To facilitate the above-described operation of the locking mechanism
701, the
socket 512a is open ended at both ends 530a, 531a and the throughbore 5124
joins the ends 530a,
531 a. This permits insertion of the stationary joint portion 525 into the
socket 512a such that the
lower portion 5258 extends below the socket S 12a. Also, stationary joint
portion 525 includes a
bore 5260 which communicates externally of the stationary joint portion 525
through a hole 5262
provided in the sidewall of the lower portion 5258. The bore 5260 and the hole
5262
accommodate the locking mechanism 701.
[0064] The locking mechanism 701 includes a detent pin spring 705 having first
and
second portions 707, 709, and the detent pin 703 coupled to the spring 705
between the first and
second portions 707, ?09. The detent spring 705 is disposed within the bore
5260. When the
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locking mechanism 701 is in the operative condition, the first and second
portions 707, 709 bear
against a respective one of opposing inner surface portions of the stationary
joint portion 525,
and the detent pin 703 is positioned within and extends through the hole 5262
and outwardly
relative to the lower portion 5258 (thereby providing a means for interfering
with upwards
displacement of the stationary joint end 525 relative to the socket 512a, as
discussed above) by
the biasing force exerted by the spring 705. When the locking mechanism 701 is
in the
inoperative condition, the detent pin 703 is positioned in alignment with the
hole 5262 but
disposed so as not to extend outwardly relative to the external surface of the
lower portion 5258.
In this position, the detent pin 703 does not interfere with upwards
displacement of the stationary
joint portion 525 relative to the socket, and thereby permits the stationary
joint end 525 to be
pulled out of the socket 512. The detent pin 703 can be moved to this position
from its extended
position outside of the hole 5262 by applying a manual force on the pin 703 in
a direction
opposite to, and overcoming the biasing force imparted by the spring 705.
[0065] The armrest joint portion 516 is rotatably connected to the armrest
coupling
linkage 575 closer to the front of the chair 10 relative to the connection of
an armrest joint
portion 616 of the swivel linkage 670 to the armrest coupling linkage 575 (see
below). The
armrest joint portion 516 preferably includes upper and lower concentric
cylindrical segments
5162, 5164. The diameter of the lower segment 5164 is greater than the
diameter of the upper
segment 5162. The segment 5162 is received within a bore 5753 of a cylindrical
tubular
segment 5752 of the armrest coupling linkage 575, and thereby is rotatably
engaged to the
segment 5752. The upper segment 5162 is joined to the lower segment 5164 by a
surface 5166
extending peripherally and outwardly from the upper segment 5162. The surface
5164 functions
as a shoulder or seating surface upon which the segment 5752 of the linkage
575 is seated when
the segment 5162 is disposed within the segment 5752, thereby effecting
vertical support of the
segment 5752 by the surface 5164. The armrest joint portion 516 is configured
for rotation
relative to the segment 5752 about a vertical axis 5161.
[0066] The swivel linkage 570 is, therefore, rotatably coupled to the
stationary linkage
656 for rotation about the vertical axis 5251, and is also rotatably coupled
to the armrest
CA 02501419 2005-03-18
coupling linkage 575 for rotation about the vertical axis 5161. The horizontal
distance between
the axis 5251 and the axis 5161 is denoted by reference numeral 2 (see Figure
7).
[0067] The swivel linkage 670 includes a stationary linkage joint portion 625
and an
armrest joint portion 616. The stationary linkage joint portion 625 is offset
from the armrest
joint portion 616 and joined to the armrest joint portion 616 by a laterally
extending connector
617. The stationary linkage portion 565 is rotatably connected to the socket
5126 of the
stationary linkage 665, thereby facilitating rotatable movement of the swivel
linkage 670 about
the axis passing through the socket 5126.
[0068] The stationary joint portion 625 includes upper and lower concentric
cylindrical
segments 6252, 6254. The diameter of the upper segment 6252 is greater than
the diameter of
the lower segment 6254. The segment 6254 is received within and rotatably
engaged to the
socket 5126. The lower segment 6254 is joined to the upper segment 6252 by a
surface 6256
extending peripherally and outwardly from the lower segment 6254. The surface
6256 is seated
upon a shoulder portion 6122 of the socket 512 (and thereby effecting vertical
support of the
surface 6256 by the shoulder portion 6122) when the tube segment 6254 is
received within the
socket 5126. In this respect, the stationary joint portion 625 is rotatably
connected to the socket
5126 and is configured for rotation relative to the socket 5126 about a
vertical axis 6251.
[0069] A locking mechanism 801 is provided to prevent disengagement of the
stationary
joint portion 625 from the socket 5126 by limiting upwards displacement of the
stationary joint
portion 625 relative to the socket 5126. When the locking mechanism 801 is in
the operative
condition, the stationary joint portion 625 is secured to the socket 5126.
When the locking
mechanism 801 is in an inoperative condition, the stationary joint portion 625
is unsecured
relative to the socket 5126. The stationary joint portion 625 is secured to
the socket 5126 by
effecting interference of upwards displacement of the stationary joint portion
625 relative to the
socket 5126. Such interference is accommodated by having the stationary joint
portion 625
extend through and below the socket 5126, and having a lower portion 6258 of
the lower
segment 6254 of the stationary joint portion 625 extending below the socket
5126 coupled to a
moveable detent 803 which is configured to abut against a lower end of the
socket S 126 if an
attempt is made to pull the stationary joint portion 625 out of the socket
5126.
CA 02501419 2005-03-18
16
[0070] In order for the stationary joint portion 625 to assume an unsecured
condition
relative to the socket 512b, the detent 803 is configured so as to be capable
of receding to a
position which does not interfere with the upwards displacement of the
stationary joint portion
625 relative to the socket 512b. When the detent 803 is so receded, the
locking mechanism 801
is in the inoperative condition. When the detent 803 is in the outwardly
extended position,
interfering with the upwards displacement as described above, the locking
mechanism 801 is in
the operative condition.
[0071] To facilitate the above-described operation of the locking mechanism
801, the
socket 512b is open ended at both ends 630a, 631a and the throughbore 6124
joins the ends
630a, 631a. This permits insertion of the stationary joint portion 625 into
the socket 512b such
that the lower portion 6258 extends below the socket 512b. Also, stationary
joint portion 6525
includes a bore 6260 which communicates externally of the stationary joint
portion 625 through
a hole 6262 provided in the sidewall of the lower portion 6258. The bore 6260
and the hole 6262
accommodate the locking mechanism 801.
[0072] The locking mechanism 801 includes a detent pin spring 805 having first
and
second portions 807, 809, and the detent pin 803 coupled to the spring 805
between the first and
second portions 807, 809. The detent spring 805 is disposed within the bore
6260. When the
locking mechanism is in the operative condition, the first and second portions
807, 809 bear
against a respective one of opposing inner surface portions of the stationary
joint portion 625,
and the detent pin 803 is positioned within and extends through the hole 6262
and outwardly
relative to the lower portion 6258 (thereby providing a means for interfering
with upwards
displacement of the stationary joint end 525 relative to the socket 512a, as
discussed above) by
the biasing force exerted by the spring 805. When the locking mechanism 801 is
in the
inoperative condition, the detent pin 803 is positioned in alignment with the
hole 6262 but
disposed so as not to extend outwardly relative to the external surface of the
lower portion 6258.
In this position, the detent pin 803 does not interfere with upwards
displacement of the stationary
joint portion 625 relative to the socket, and thereby permits the stationary
joint end 625 to be
pulled out of the socket 512. The detent pin 803 can be moved to this position
from its extended
CA 02501419 2005-03-18
17
position outside of the hole 6262 by applying a manual force on the pin 803 in
a direction
opposite to, and overcoming the biasing force imparted by the spring 805.
[0073] The armrest joint portion 616 is rotatably connected to the armrest
coupling
linkage 575 closer to the back of the chair 10 relative to the connection of
an armrest joint
portion 516 of the swivel linkage 570 to the armrest coupling linkage 575. The
armrest joint
portion 616 preferably includes upper and lower concentric cylindrical
segments 6162, 6164.
The diameter of the lower segment 6164 is greater than the diameter of the
upper segment 6162.
The segment 6162 is received within a bore 6753 of a cylindrical, tubular
segment 6752 of the
armrest coupling linkage 575, and thereby is rotatably engaged to the segment
6752. The upper
segment 6162 is joined to the lower segment 6164 by a surface 6166 extending
peripherally and
outwardly from the upper segment 6162. The surface 6164 functions as a
shoulder or seating
surface upon which the segment 6752 of the linkage 575 is seated when the
segment 6162 is
disposed within the segment 6752, thereby effecting vertical support of the
segment 6752 by the
surface 6166. The armrest joint portion 616 is configured for rotation
relative to the segment
6752 about a vertical axis 6161.
[0074] The swivel linkage 670 is, therefore, rotatably coupled to the
stationary linkage
565 for rotation about the vertical axis 6251, and is also rotatably coupled
to the armrest
coupling linkage about the vertical axis 6161. The horizontal distance between
the axis 6251 and
the axis 6161 is denoted by reference numeral 4 (see Figure 7).
[0075] In one embodiment, the horizontal distance 2 is the same or
substantially the same
as the horizontal distance 4. In another embodiment, the horizontal distance 2
is at least 1.2
times longer than the horizontal distance 4 (ie. the ratio of the horizontal
distance 2 to the
horizontal distance 4 is 1.2). For example, the horizontal distance 2 is at
least 1.5 times longer
than the horizontal distance 4. As a further, further example, the horizontal
distance is at least
two (2) times longer than the horizontal distance 4. By having the horizontal
distance 2 being
longer than the horizontal distance 4, additional space is provided between
the armrest
assemblies SOOa, SOOb closer to the front of the chair than closer to the rear
of the chair 10.
Typically, a bariatric patient seated in the chair 10 requires additional room
for comfort closer to
CA 02501419 2005-03-18
18
the front of the chair, and this is accommodated by having the horizontal
distance 2 being longer
than the horizontal distance 4.
[0076] The armrest coupling linkage 575 includes a front joint portion 589
from which
the segment 5752 extends downwardly, and a back joint portion 591, from which
the segment
6752 extends downwardly. The armrest linkage 575 is rotatably connected to
each of (i) the
armrest joint portion 516 of linkage 570, and (ii) the armrest joint portion
616 of the linkage 670,
by a respective one of the segments 5752, 6752, thereby permitting rotatable
movement of the
swivel linkages 570, 670 about the respective axes 5161, 6161 and lateral
movement of the
armrest coupling linkage 575 relative to the stationary linkage 565 (and also,
therefore, relative
to the chair 10).
[0077] The front and back joint portions 589, 591 are joined by an elongated
frame
member 520. The armrest member 522 is suitably connected to the elongated
member 520 so as
to present a surface upon which a person seated in the chair can rest his or
her arms on the
armrest member 522 for support. In the illustrated embodiment, the armrest
member 522 is
connected to the frame member 520 by screws 521a, 521b.
[0078] A locking mechanism 900 is provided to selectively limit relative
rotational
movement between the swivel linkage 570 and the armrest coupling linkage 575
and between the
swivel linkage 670 and the armrest coupling linkage 575, when the armrest is
in any one of a
first narrow armrest position, an intermediate wide armrest position, or a
second narrow armrest
position. An example of the above-described relative rotational movement being
limited by the
locking mechanism 900 is when the above-described relative rotational movement
is
substantially prevented by the locking mechanism 900. In this context, the
term "substantially
prevented" means that the above-described relative rotational movement may or
may not be
prevented, and if not prevented, the above-described relative rotational
movement is limited such
that the relative rotational movement between the linkages 570, 670 and the
linkage 575 is minor
and not sufficiently significant so as to noticeably derogate from the chair
occupant's
expectations that his or her arm is maintained in a stationary position when
supported on the
armrest member 552.
CA 02501419 2005-03-18
19
[0079] The locking mechanism 900 includes at least a first locking element
902. The
first locking element 902 is configured to act between the swivel linkage 570
and the armrest
coupling linkage 575 to oppose tangential forces relative to swivel linkages
560, 670, being
applied by the armrest coupling linkage 575 that would otherwise effect
swivelling of the
linkages 560, 570. This limits (for example, substantially prevents) the above-
described
rotational movement of the linkages 560, 670 relative to the linkage 575 and
thereby maintain
the armrest 522 in any one of the three above-described positions. In the
illustrated embodiment,
the locking mechanism 900 includes a second locking element 952. The second
locking element
952 is configured to act between the swivel linkage 670 and the armrest
coupling linkage 575 to
oppose tangential forces relative to swivel linkages 560, 670, being applied
by armrest coupling
linkage 575 that would otherwise effect swivelling of the linkages 560, 670.
This assists locking
element 902 by distributing loading between two locking elements instead of
only one locking
element in limiting (for example, substantially preventing) the above-
described relative
rotational movements.
[0080] The locking mechanism 900 is in the operative condition when relative
rotational
movement between the swivel linkage 570 and the armrest coupling linkage 575,
and between
the swivel linkage 670 and the armrest coupling linkage 575, is limited (for
example,
substantially prevented). The locking mechanism 900 is in the operative
condition when at least
one of the locking elements 902, 952 is acting between the armrest coupling
linkage 575 and a
respective one of the swivel linkages 570, 670. When both of the locking
elements 902, 952 are
acting in this manner, each locking element 902, 952 is individually described
as being in an
operative condition.
[0081 ] The locking mechanism 900 is in the inoperative condition when each of
the
swivel linkages 570, 670 is free to rotate relative to the armrest coupling
linkage 575, subject to
any interference to the rotational movement provided by other components of
the assembly 500
or the chair 10 (such as stationary linkage 565). The locking mechanism 900 is
in the
inoperative condition when the locking element 902 is not acting between the
armrest coupling
linkage 575 and the swivel linkage 570 (in which case, locking element 902 can
also be
described as being in an "inoperative condition"), and the locking element 952
is not acting
CA 02501419 2005-03-18
between the armrest coupling linkage 575 and the swivel linkage 670 (in which
case, locking
element 952 can also be described as being in an "inoperative condition"). In
other words, for
the locking mechanism 900 to be in the inoperative condition, each of the
locking elements 902,
952 must also be in the inoperative condition.
[0082] The locking element 902 acts between the swivel linkage 570 and the
armrest
coupling linkage 575 by effecting interference of relative rotational movement
between the
swivel linkage 570 and the armrest coupling linkage 575 (as well as linkages
670 and 575). The
locking element 902 is coupled to the swivel linkage 570 and includes a
moveable detent pin
904. The detent pin 904 is configured to be received within and extend through
an armrest
linkage hole 528 provided in the sidewall of the segment 5752 of the armrest
coupling linkage
575. In other words, the detent pin 904 is configured to interfere with the
relative rotational
movement between the swivel linkage 570 and the armrest coupling linkage 575.
In this respect,
when the detent pin 904 extends through the armrest linkage hole 528, and an
attempt is made to
effect relative rotation between the swivel linkage 560 and the armrest
coupling linkage 575, the
detent pin 904 becomes abutted against an inner edge surface of the armrest
coupling linkage
575 which defines the hole 528, thereby limiting relative rotational movement
between the
swivel linkage 570 and the armrest coupling linkage 575.
[0083] In order for the swivel linkage 570 to assume an unsecured condition
relative to
the armrest coupling linkage 575, the detent pin 904 is configured to be
capable of receding to a
position which does not interfere with the relative rotational movement
between the swivel
linkage 570 and the armrest coupling linkage 575. When the detent pin 904 is
so receded, the
locking element 902 in the inoperative condition. When the detent pin 904 is
in an outwardly
extended position, extending through the hole 528, and thereby interfering
with the above-
described relative rotational movement, the locking element 902 is in the
operative condition.
[0084] To accommodate the locking element 902, the armrest joint portion S 16
of the
swivel linkage 570 includes a bore 5601 which communicates externally of the
armrest joint
portion 516 through a swivel linkage hole 523 provided in the sidewall of the
upper segment
5162.
CA 02501419 2005-03-18
21
[0085] The locking element 902 includes a detent spring 906 having first and
second
portions 908, 910. The detent pin 904 is coupled to the spring 906 between the
first and second
portions 908, 910. The detent spring 906 is disposed within the bore 5601 and
the first and
second portions 908, 910 bear against a respective one of opposing inner
surface portions of the
armrest joint portion 516.
[0086] When the locking element 902 is in the operative condition, both of the
armrest
linkage hole 528 and the swivel linkage hole 523 are aligned, the first and
second portions 908,
910 bear against a respective one of opposing inner surface portions of the
armrest joint portion
516, and the detent pin 904 is positioned within and extends through each of
the swivel linkage
hole 523 and the armrest linkage hole 528 by the biasing force exerted by the
spring 906.
[0087] When the locking element 902 is in the inoperative condition, the
detent pin 904
extends through the swivel linkage hole 523 but does not extend into the
armrest linkage hole
528 and, therefore, does not interfere with relative rotational movement
between the swivel
linkage 560 and the armrest coupling linkage 575. The detent pin 904 can be
moved to this
receded position from its extended position through the hole 528 by applying a
manual force on
the pin 904 in a direction opposite to, and overcoming the biasing force
imparted by the spring
906.
[0088] Once the pin 904 is moved into and maintained in this receded position,
the
swivel linkage 560 and the armrest coupling linkage 575 can be meaningfully
rotated relative to
one another, thereby taking the holes 523 and 528 out of alignment. As a
result, the detent pin
904 is biased into a position wherein the detent pin 904 extends through the
swivel linkage hole
526 and is in sliding contact with the inner surface of the bore 5753 of the
segment 5752.
However, such contact does not interfere with relative rotational movement
between the swivel
linkage 560 and the armrest coupling linkage 575 so long as the friction
created by spring 906,
between detent pin 904 and the inner surface of the bore 5753 is significantly
less than the
rotational force acting at that interface. For example, this would be the case
where the bore 5753
has a circular or substantially circular cross-section along its length which
receives the segment
5162.
CA 02501419 2005-03-18
22
[0089] The segment 5752 includes a plurality of holes 528 about its perimeter,
wherein
each of the plurality of holes corresponds to a desired indexed position of
the armrest 522. In the
illustrated embodiment, the segment 5752 includes three (3) holes 528, wherein
each of the holes
528 corresponds to a respective one of a first narrow armrest position, an
intermediate wide
armrest position, and a second narrow armrest position. The armrest 522 is
disposed in one of
these positions whenever the detent pin 904 extends through a respective one
of the holes 528.
The armrest 522 moves between these positions as the armrest coupling linkage
575 rotates
relative to the swivel linkage 560 from a position of alignment of one of the
holes 528 with the
hole 523 of the swivel linkage 560 (ie. a first operative condition of the
locking element 902) to a
position of alignment of another one of the holes 528 with the hole 523 (ie. a
second operative
condition of the locking element 902).
[0090] The locking element 952 acts between the swivel linkage 670 and the
armrest
coupling linkage 575 by effecting interference of relative rotational movement
between the
swivel linkage 670 and the armrest coupling linkage 575. The locking element
952 is coupled to
the swivel linkage 670 and includes a moveable detent pin 954. The detent pin
954 is configured
to be received within and extend through an armrest linkage hole 628 provided
in the sidewall of
the segment 6752 of the armrest coupling linkage 575. In other words, the
detent pin 954 is
configured to interfere with the relative rotational movement between the
swivel linkage 670 and
the armrest coupling linkage 575. In this respect, when the detent pin 954
extends through the
armrest linkage hole 628, and an attempt is made to effect relative rotation
between the swivel
linkage 570 and the armrest coupling linkage 575, the detent pin 954 becomes
abutted against an
inner edge surface of the armrest coupling linkage 575 which defines the hole
628, thereby
limiting relative rotational movement between the swivel linkage 670 and the
armrest coupling
linkage 575.
[0091 ] In order for the swivel linkage 670 to assume an unsecured condition
relative to
the armrest coupling linkage 575, the detent pin 954 is configured to be
capable of receding to a
position which does not interfere with the relative rotational movement
between the swivel
linkage 670 and the armrest coupling linkage 575. When the detent pin 954 is
so receded, the
locking element 952 is in the inoperative condition. When the detent pin 954
is in an outwardly
CA 02501419 2005-03-18
23
extended position, extending through the hole 628, and thereby interfering
with the above-
described relative rotational movement, the locking element 952 is in the
operative condition.
[0092] To accommodate the locking element 952, the armrest joint portion 616
of the
swivel linkage 670 includes a bore 6601 which communicates externally of the
armrest joint
portion 616 through a swivel linkage hole 623 provided in the upper segment
6162.
[0093] The locking element 952 includes a detent spring 956 having first and
second
portions 958, 960. A detent pin 956 is coupled to the spring 956 between the
first and second
portions 958, 960. The detent spring 956 is disposed within the bore 6601 and
the first and
second portions 908, 910 bear against a respective one of opposing inner
surface portions of the
armrest joint portion 616.
[0094] When the locking element 660 is in the operative condition, both of the
armrest
linkage hole 628 and the swivel linkage hole 623 are aligned, the first and
second portions 958,
960 bear against a respective one of opposing inner surface portions of the
armrest joint portion
516, and the detent pin 954 is positioned within and extends through each of
the swivel linkage
hole 623 and the armrest linkage hole 628 by the biasing force exerted by the
spring 956.
[0095] When the locking element 954 is in the inoperative condition, the
detent pin 954
extends through the swivel linkage hole 623 but does not extend into the
armrest linkage hole
628 and, therefore, does not interfere with relative rotational movement
between the swivel
linkage 670 and the armrest coupling linkage 575. The detent pin 954 can be
moved to this
receded position from its extended position through the hole 628 by applying a
manual force on
the pin 954 in a direction opposite to, and overcoming the biasing force
imparted by the spring
956.
[0096] Once the pin 954 is moved into and maintained in this receded position,
the
swivel linkage 670 and the armrest coupling linkage 575 can be rotated
relative to one another,
thereby taking the holes 623 and 628 out of alignment. As a result, the detent
pin 954 is biased
into a position wherein the detent pin 954 extends through the swivel linkage
hole 628 and is in
sliding contact with the inner surface of the bore 6753 of the segment 6752.
However, such
CA 02501419 2005-03-18
24
contact does not interfere with relative rotational movement between the
swivel linkage 670 and
the armrest coupling linkage 575 so long as the friction created by the spring
906 between detent
pin 904 and the inner surface of the bore 6753 is significantly less than the
rotational force acting
at that interface. For example, this would be the case where the bore 6753 has
a circular or
substantially circular cross-section along its length which receives segment
6162.
[0097] The segment 6752 includes a plurality of holes 628 about its perimeter,
wherein
each of the plurality of holes corresponds to a desired indexed position of
the armrest 522. In the
illustrated embodiment, the segment 6752 includes three (3) holes 628, wherein
each of the holes
628 corresponds to a respective one of a forward narrow armrest position, an
intermediate wide
armrest position, and a rear narrow armrest position. The armrest 522 is
disposed in one of these
positions whenever the detent pin 954 extends through a respective one of the
holes 628. The
armrest 522 moves between these positions as the armrest coupling linkage 575
rotates relative
to the swivel linkage 670 from a position of alignment of one of the holes 628
with the hole 623
of the swivel linkage 670 (ie. a first operative condition of the locking
element 952) to a position
of alignment of another one of the holes 628 with the hole 623 (ie. a second
operative condition
of the locking element 952).
[0098] The armrest assembly 500 is moveable between at least three indexed
positions.
In the embodiment illustrated in Figures 1, 8, 9 and 10, the armrest assembly
500 is moveable
between three indexed positions, namely: a forward narrow position (Figure 8),
in which the
armrest 522 is in a narrow position at about the front end of the chair 10, a
mid-wide position
(Figure 9), in which the armrest 522 is in a wide position at about the mid-
point of the chair 10,
and a rear narrow position (Figure 10), in which the armrest 522 is in a
narrow position at about
the back of the chair 10. As the assembly 500 moves to each of these
positions, the armrest 522
follows an arc-like path, which is generally indicated by the arrow in each of
Figures 8, 9 and 10.
This arc-like path, results in lateral movement of the armrest 522 relative to
the chair 10,
between a forward narrow position, an intermediate wide position, and a
rearward narrow
position. For example, the lateral distance moved between either of the narrow
positions and the
wide position is no greater than three (3) inches. As a further example, this
lateral distance
moved is two (2) inches.
CA 02501419 2005-03-18
[0099] In an alternate embodiment, the coupling member 555 comprises a single
swivel
linkage of a configuration identical to that of either swivel linkage 570 or
670, and would be
rotatably connected to the stationary linkage 565 in an identical manner to
that described for the
coupling of either of the swivel linkages 570, 670 to a respective one of the
sockets 12a, 12b of
the stationary linkage 565. The single swivel linkage would be further
rotatably connected to the
armrest coupling linkage 575 in an identical manner to that described for the
coupling of either
of the swivel linkages 570, 670 to the respective one of the segments 5752,
6752 of the armrest
coupling linkage 575. For example, the single swivel linkage would be
connected to the armrest
coupling linkage 575 at about a midpoint of the armrest coupling linkage 575
(as opposed to one
of the end portions 589, 591) so as to realize a more stable structure. The
locking mechanism
900 associated with the single swivel linkage would be a single locking
element 902 or 954, and
would be configured to limit (for example, substantially prevent) relative
rotational movement
between the single swivel linkage and the armrest coupling linkage 575. Also,
a single locking
mechanism of the configuration described and illustrated for either locking
mechanism 701 or
801 could also be provided for preventing disengagement of the stationary
joint portion of the
single swivel linkage from an associated socket of the linkage 575.
[00100] In another embodiment the armrest assembly 500 includes more than two
swivel
linkages to effect coupling of the linkage 575 to the linkage 565.
[00101 ] Movement of the illustrated embodiment of the armrest 522 between the
forward
narrow position, the wide position, and the rearward narrow position will now
be described.
Initially, the armrest 522 is in the forward narrow position (see Figure 8),
and each of the locking
elements 902, 952 is in the operative condition. As a first step, each of the
detent pins 904, 954
is manually depressed so that they recede into each of their corresponding
respective holes 528,
628, such that the detent pins 904, 954 are in a position wherein they cannot
interfere with a
respective one of relative rotational movement between linkage 570 and linkage
575 and relative
rotational movement between linkage 670 and linkage 575 (ie. the locking
elements 902, 952 are
in the inoperative condition). A manual force is then applied to the
intermediate armrest 522 to
effect movement of the armrest 522 in an arc-like path from the forward narrow
position to the
wide position (see Figure 9). As the armrest 522 moves in this manner, each of
the linkages 570,
CA 02501419 2005-03-18
26
670 rotates relative to the linkages 575, and each of the detent pins 904, 954
moves out of
alignment with a respective one of a first set of holes 528, 628. When the
armrest 522 assumes
the intermediate wide position, each of the detent pins 904, 954 is biased to
extend through a
respective one of the second set of holes 528, 568 so that each of the locking
elements 902, 952
assumes a second operative position, thereby locking the armrest 522 in the
intermediate wide
position. To move the armrest 522 from the intermediate wide position to the
rearward position
(see Figure 10), the detent pins 904, 954 are, again, manually depressed so
that they recede into
each of their corresponding respective holes 528, 628, such that the detent
pins 904, 954 are in a
position whereby they cannot interfere with a respective one of relative
rotational movement
between linkage 570 and linkage 575 and relative rotational movement between
linkage 670 and
linkage 575 (ie. the locking elements 902, 952 are in the inoperative
condition) A manual force
is then applied to the armrest to effect movement of the armrest in an arc-
like path from the
intermediate wide position to the rearward position (See Figure 10). As the
armrest 522 moves
in this manner, each of the linkages 570, 670 rotates relative to the linkage
575, and each of the
detent pins 904, 954 moves out of alignment with a respective one of the
second set of holes 528,
628. When the armrest 522 assumes the rearward narrow position, each of the
detent pins 904,
954 assumes alignment with a respective one of a third set of holes 528, 628,
and the detent pins
are biased to extend through a respective one of the third set of holes 528,
628, so that each of
the locking elements 902, 952 assumes a third operative position, thereby
locking the armrest
522 in the rearward position.
[00102] Refernng to Figures 6, 7, 11 and 12, the locking mechanism 900 may
further
include a threaded handwheel to act between at least one of (i) the linkage
560 and the linkage
575, and (ii) the linkage 670 and the linkage 575, and thereby provide a
further means for
effecting interference of relative rotational movement between both sets of
linkages (linkages
560, 575 and linkages 570, 575). In the illustrated embodiment, two threaded
handwheels 1001,
1101 are provided. The handwheel 1001 acts between the linkage 560 and the
linkage 575. The
handwheel 1101 acts between the linkage 670 and the linkage 575.
[00103] The handwheel 1001 includes a threaded rod 1003 that threadably
engages a
projection nut 1005 coupled to the segment 5752 of the linkage 575. The nut
1005 defines a
CA 02501419 2005-03-18
27
bore 1007 which is co-axial with an opening provided in the segment 5752 of
the armrest
coupling linkage 575. The opening is a circular hole that has a diameter which
is large enough to
accept the major diameter of the threaded rod 1003. The handwheel 1001 can be
turned so as to
extend through the opening and bear against the upper segment 5162 of the
armrest joint portion
516 of the swivel linkage 560, thereby interfering with relative rotational
movement between the
linkages 560 and 575 (as well as linkages 570 and 575). The second handwheel
1101 is
configured to bear against linkage 570 in a similar manner. The handwheel 1101
includes a
threaded rod 1103 that threadably engages a projection nut 1105 coupled to the
segment 6752 of
the linkage 575. The nut 1105 defines a bore 1107 which is co-axial with an
opening provided in
the segment 6752. The opening is a circular hold that has a diameter which is
large enough to
accept the major diameter of the threaded rod 1003. The handwheel can be
turned so as to
extend through the opening and bear against the upper segment 6162 of the
armrest joint portion
616 of the swivel linkage 670, thereby interfering with relative rotational
movement between the
linkages 670 and 575 (as well as linkages 560 and 575).
[00104] Each of the handwheels 1001, 1101 is capable of limiting relative
movement
between both sets of linkages when the armrest 522 is not disposed in one of
the three indexed
positions (ie. the armrest 522 is disposed in a non-indexed position), which
is the case when
holes 523 and 528 are out of alignment (or when holes 623 and 628 are out of
alignment).
[00105] Accordingly, when the detent pins 904, 954 and the handwheel 1001 are
in their
respective disengaged positions, the armrest linkage 575 may be moved to a
desired lateral
position (Figure 12). If this position does not correspond to an indexed
position, then the
handwheel 1003 may be engaged to thereby lock the sets of linkages and prevent
further lateral
movement of the armrest linkage 575 (Figure 11).
[00106] In one embodiment, the adjustable armrest assembly is coupled to the
chair 10.
Refernng to Figure 1, the chair 10 is provided including a chair frame 12, a
seat 14, and a
backrest 16. The chair frame 12 supports the seat 14 and the backrest 16 upon
a reaction surface
8.
CA 02501419 2005-03-18
28
[00107] Refernng to Figure 16, the chair frame 12 includes a structural frame
supported
on rolling means. The structural frame comprises two unitary side structures
900a, 900b joined
by cross braces 961, 962. The elements of the structural frame are made of one
inch diameter,
16 gauge (ie. 0.065 of an inch wall thickness) stainless steel tubing. The
structural frame is
supported on each side by front casters 100a, 100b and rear casters 110a,
110b, and a wheel
lOla, lOlb intermediate the front and rear casters. For example, the casters
100a, 100b, 110a,
110b are TenteTM brand five inch diameter stainless steel locking casters. For
example, the
wheels lOla, lOlb are ColsonTM brand eight inch diameter PerformaTM wheels
with stainless
steel axles.
[00108] The chair frame 12 includes two unitary side structures 900a, 900b.
Each of the
side structures 900a, 900b includes a respective one of upper rails 90a, 90b,
a respective one of
front vertical members 91a, 91b, and a respective one of lower rails 93a, 93b.
Each of the upper
rails 90a, 90b and each of the lower rails 93a, 93b extend rearwardly from a
respective one of the
front vertical member 91a, 91b and are joined to a respective one of rear
vertical members 911a,
91 1b at the rear of the chair frame 12.
[00109] The unitary structures 900a, 900b are joined together by cross braces
961, 962.
Spaced apart lowered cross member braces 98a, 98b extend rearwardly and
downwardly from
cross brace 961.
[00110] Each brace 98a, 98b is pivotally coupled to one end of a respective
one of a pair
of extendible/retractable members 200a, 200b (see Figure 1, 2, and 4) by a
respective bolt
extending through a respective pair of aligned apertures, one of the
respective pair of aligned
apertures being provided in a respective one of the braces 98a, 98b and the
other being provided
in a respective one of the members 200a, 200b. Each of the
extendible/retractable members
200a, 200b is pivotally coupled at a second opposite end to the seat 14 (see
below) by a
respective bolt extending through a respective pair of aligned aperture, one
of the respective pair
of aligned apertures being provided in a respective one of a pair of posts
81a, 81b provided on
the seat frame 18 (see below) and the other of the respective pair of aligned
apertures being
provided in a respective one of the members 200a, 200b. The members 200a, 200b
support the
seat 14 in various positions of tilt.
CA 02501419 2005-03-18
29
[00111] A lowered cross brace 97 is also provided, extending between and
joining the
unitary structures 900a, 900b, and coupled to each of the braces 98a, 98b. The
brace 97 provides
additional support to the braces 98a, 98b which are loaded by the weight of
the chair occupant
being translated to the extendible/retractable members 200a, 200b.
[00112] Each of the front casters 100a, 100b is coupled to and depends from
the lower end
of a respective one of the front vertical members 91a, 91b. Each of the rear
casters 110a, 1 lOb is
coupled to and depends from a respective one of the rear vertical members
911a, 911b. Each of
fixed wheels 101 a, 101 b is provided intermediate respective casters 1 OOa,
100b and casters 110a,
110b. Each of the wheels lOla, lOlb is coupled to a respective one of the
upper rails 90a, 90b
by a respective one of first and second forks 94a, 94b and 95a, 95b.
(00113] The seat 14 is coupled to the chair frame 12. The seat 14 includes a
seat frame 18
and a seating element 19 having a seating surface 20. The seating surface 20
is configured for
generally receiving and supporting a portion of the bottom torso of a person
occupying the chair
(the "chair occupant"). The seating surface 20 can be a continuous or a
discontinuous surface.
The seating surface 20 can include discontinuous portions so long as the
seating surface 20
performs the function of providing the necessary support to the chair
occupant. An example of a
suitable discontinuous surface is a plurality of spaced apart vinyl straps
that are coupled to the
seat frame. The plurality of vinyl straps function, in concert, to provide the
necessary support to
the chair occupant, and the existence of spaces between the vinyl straps does
not necessarily
render the vinyl straps incapable of performing the above-described function.
[00114] In the illustrated embodiment, the seating element 19 is configured to
permit the
chair occupant to expel bodily wastes into a receiving container 73 disposed
below the seat (as
further described below). In this respect, the seating element 19 includes a
centrally positioned
opening 22 defined by the seating surface 20 extending from and merging with a
front edge 24 of
the seating surface 20. The front edge 24 extends laterally from either side
of the opening 22 and
merges with side edges 26, 28 of the seating surface 20. The side edges 26, 28
extend from the
front edge 24 to a rear edge 30 of the seating surface 20. The rear edge 30 is
disposed opposite
to the front edge 24 and joins the side edges 26, 28. It is understood that
any of the front edge
24, rear edge 30, or side edges 26, 28 can be continuous or discontinuous. In
this respect, these
CA 02501419 2005-03-18
edges can include discontinuous portions so long as such edge or edges define
the perimeter of a
seating surface which functions to provide the necessary support to the chair
occupant.
[00115] A width of the seating surface 20 is defined as any distance of the
seating surface
20 (including any discontinuous portions of the surface 20) between the side
edges 26, 28 and
along any vertical plane parallel to a vertical plane that is tangent to the
most forwardly disposed
surface of the front edge 24. A length of the seating surface 20 is defined as
any distance of the
seating surface 20 (including any discontinuous portions of the surface 20)
between the front
edge 24 and the rear edge 30 and along any vertical plane having a transverse
axis that is
perpendicular to the normal axis of a vertical plane tangent to the most
forwardly disposed
outermost surface of the front edge 24.
[00116] The seating surface 20 includes a seating surface portion having a
minimum width
and a minimum length. In this respect, the width and/or the length may not be
consistently the
same for the entire seating surface portion but, rather, may vary between a
minimum and a
maximum. For example, the minimum width is 27 inches and the minimum length is
22 inches.
As a further example, the minimum width is at least 18 inches, and the minimum
length is at
least 20 inches. In yet a further example, the minimum width is between 18
inches and 38
inches, and the minimum length is between 16 inches and 24 inches.
[00117] For example, the seating element 19 is constructed with black
polyurethane foam
molded over a medium density fiberboard structural inner core. It is coupled
to the seat frame
via four polyurethane foam locating bosses 2002a, 2002b 2003a, 2003b and a
front locating
flange 2001 (see Figure 42) that are molded on the underside of the seating
element 19 and are
configured for alignment with the structural elements of the seat frame 18 to
prevent the seat
from sliding relative to the seat frame 18. The seat remains positioned on the
seat regardless of
shifts in weight because the foam locating bosses mate with the structural
elements of the seat
frame and, because of the friction created by the weight of the occupant
bearing down on the
foam seat and the seat frame. As long as the planar force created by the shift
in weight of the
occupant does not exceed the combined shear threshold of the locating bosses
and the interface
friction between the foam seat and the seat frame, then the seat remains
substantially stationary.
CA 02501419 2005-03-18
31
[00118] Referring to Figure 1 S, the seat frame 18 is made of one inch square,
16 gauge (ie.
0.065 of an inch wall thickness) stainless steel tube and includes a pair of
unitary side structures
800a, 800b, each coupled to a respective one of the sides of a main support
structure 700. The
main support structure 700 includes a tube structure 77 for supporting the
seating surface 20 and
the receiving container 73. The tube structure 77 is shaped to facilitate
unobstructed
communication between an opening 22 (defined by the seating surface 20) and
the receiving
container 73 vertically aligned with the opening 22. The main support
structure 700 includes a
pair of spaced apart posts 82a, 82b for pivotal coupling of a legrest 300
thereto by a pair of bolts,
each of the bolts extending through a respective pair of aligned apertures,
one of the respective
pair of aligned apertures being provided in a respective one of posts 82a, 82b
and the other of the
respective pair of aligned apertures being provided in a respective one of an
opposing pair of
portions of the legrest 300. The main support structure 700 also includes u-
shaped members 78,
79 provided for effecting support of the receiving container 73. The u-shaped
members 78, 79
are coupled to and depend below the tube structure 77 in spaced apart relation
to each other.
Tube end caps 88 are provided to close the apertures of the tube structures.
[00119] In the illustrated embodiment, the receiving container 73 is in the
form of a bed
pan having a peripherally extending lip 731 with notches 732 for engaging a
resilient container
support structure 72. The container support structure 72 is, for example, a
3/16 of an inch
diameter stainless steel rod formed and welded to the desired shape. The
container support
structure 72 is provided to support and secure the receiving container 73 to
the u-shaped
members 78, 79 of the seat frame 12. The container support structure 72 is
shaped to support the
receiving container 73 about the lip 731, and includes mounting rods 75a, 75b
and 76a, 76b for
being received within corresponding apertures provided in the u-shaped members
78, 79. To
further stabilize the receiving container 73 versus the container support
structure 72, notches 732
are provided on either side of the container 73 for receiving the mounting
rods 76a, 76b. To
effect mounting of the container support structure 72 to the chair frame 12,
the container support
structure 72 is manually bent so that the mounting rods become aligned with
the corresponding
apertures, and then the mounting rods are inserted into the corresponding
apertures. The
receiving container 73 can then be mounted upon the container support
structure 72.
CA 02501419 2005-03-18
32
[00120] Each of the side structures 800a, 800b is coupled to the main support
structure
700 by a cross brace 80. Each of the side structures 800a, 800b includes a
respective one of the
upper seat rails 84a, 84b and a respective one of the lower seat rails 85a,
85b. Each of the upper
seat rails 84a, 84b extend rearwardly from a respective one of the opposite
sides of the tube
structure 77. Each one of a pair of posts 83a, 83b extends downwardly from
proximate the front
end of a respective one of the upper seat rails 84a, 84b. Each post 83a, 83b
is pivotally coupled
to a respective one of the front vertical member 91a, 91b of the chair frame
12 by a respective
bolt extending through a respective pair of aligned apertures, one of the
respective pair of aligned
apertures being provided in a respective one of the posts 83a, 83b and the
other of the respective
pair of aligned apertures being provided in a respective one of the members
91a, 91b. This
effects pivotal coupling of the seat 14 to the chair frame 12.
[00121 ] Each of the upper seat rails 84a, 84b is pivotally coupled to one end
of a
respective one of a pair of extendible/retractable support members 202a, 202b,
at a point on the
respective one of the upper seat rails 84a, 84b disposed rearwardly of the
point of pivotal
coupling of the upper seat rail 84a, 84b to the backrest 18. The pivotal
coupling between each
one of the respective pair of aligned apertures being provided in a respective
one of the rails 84a,
84b and a respective one of the members 202a, 202b is effected by a respective
bolt extending
through a respective pair of aligned apertures, one of the respective pair of
aligned apertures
being provided in a respective one of the rails 84a, 84b and the other of the
respective pair of
aligned apertures being provided in a respective one of the members 202a,
202b. Each of the
extendible/retractable support members 202a, 202b is also pivotally coupled at
an opposite end
to the backrest 16. The pivotal coupling between each of the members 202a,
202b and a
respective one of a pair of opposing portions of the backrest 16 is effected
by a respective bolt
extending through a respective pair of aligned apertures, one of the
respective pair of aligned
apertures being provided in a respective one of the members 202a, 202b and the
other being
provided in a respective one of an opposing pair of portions of the backrest
16. The members
202a, 202b enable positioning and support of the backrest 16 in various
positions of inclination
relative to the seat 14, as is further described below.
CA 02501419 2005-03-18
33
[00122] Each of the lower seat rails 85a, 85b is coupled to and extends
rearwardly from a
respective one of the posts 83a, 83b. Each of the lower seat rails 85a, 85b is
coupled to a
respective one of the pair of posts 81a, 81b at about a midpoint of the rail.
Each of the posts 81a,
81b, extends upwardly from a respective one of the rails 85a, 85b and is
pivotally coupled to a
respective one of the extendible/retractable members 200a, 200b (see above).
Each lower seat
rail 85a, 85b also includes a respective one of two pairs of armrest sockets
86a, 86b and 87a,
87b.
[00123] As discussed above, the seat 14 can be pivotally coupled to the chair
frame 12.
Pivotal coupling of the seat 14 to the chair frame 12 facilitates pivotal
movement of the
combination of the seat 14 and the backrest 16 (where the backrest 16 is
coupled to the seat 14,
as is the case in the preferred embodiment, and as will be discussed below)
relative to the chair
frame 12. In this respect, the seat 14 is capable of moving from one position
of seat tilt relative
to the frame 12 to another position of seat tilt (ie. changing the desired
degree of seat tilt).
[00124] Positioning and support of the seat 14 in various positions of tilt is
enabled by the
extendible/retractable support members 200a, 200b. The support provided by the
extendible/retractable support members 200a, 200b is adjustable, in that the
support members
200x, 200b can be locked in a first position, and then released to permit
extension or retraction of
the support member so that the desired degree of seat tilt can be changed, and
then locked again
once the seat 14 is positioned at the desired degree of seat tilt. This
facilitates changing of the
desired degree of seat tilt, while effecting support of the seat 14, upon the
seat 14 being
positioned to the desired degree of seat tilt. To accommodate this change of
positioning, and as
explained above, each of the extendible/retractable members 200a, 200b is
pivotally coupled at
one end to the chair frame 12 (ie. braces 98a, 98b) and at a second opposite
end to the seat 14 (ie.
posts 81a, 81b on the seat frame 18). Extendible/retractable members 200a,
200b are actuated
for movement by hand actuators 201 a, 201b.
[00125] Each of the extendible/retractable support members 200a, 200b is in
the form of a
gas cylinder or "spring" provided on the chair frame 12 to exert an upward
force on the seat 14
to thereby resist a downward weight of a chair occupant. A suitable gas spring
is a BLOC-O-
LIFT locking gas spring using a Bowden cable system, as manufactured by
Stabilus GmbH. A
CA 02501419 2005-03-18
34
detailed drawing of an example of the extendible/retractable support members
200a, 200b is
provided in Figure 17.
[00126] The gas spring is a closed system consisting of a pressure tube 102
and a hollow
piston rod 104 extending from the pressure tube 102. The piston rod 104
terminates in a piston
within pressure tube 102. A compressed gas is provided within tube 102. The
pressure tube 102
is separated into first and second chambers by a valve (not shown). The valve
is actuated by a
release pin which extends from the valve and through the piston rod 104, and
extends externally
of the piston rod 104 for actuation by release plate 106. When the valve is
open, in response to
depression of the release pin, the piston rod can be extended in a controlled,
dampened manner at
the defined gas spring force to the maximum extension, so long as the gas
spring force exceeds
any external opposing forces. Of course, supplementary external forces (such
as a manual force)
can be applied to supplement the gas spring force and assist in the extension
of the members
200a, 200b. This results in extension of the extendible/retractable support
members 200a, 200b.
If, while the valve is open, an external force is applied to the piston rod in
opposition to the gas
spring force, and overcoming the gas spring force, the piston rod 104 will
recede into the
pressure tube, resulting in the shortening of the length (ie. retraction) of
the members 200a, 200b.
An example of how such an external force may be applied to effect retraction
of the members
200a, 200b is application of a manual force to cross-member 40 of the backrest
frame 34 in a
generally downwards direction. As soon as the actuator pin is released from
the outside, the
valve will close automatically because of the gas pressure exerted on it. The
piston or piston rod
is then locked, as gas exchange between the chambers is interrupted. The
cylinders may thus be
releasably locked in a desired position upon the seat 14 becoming titled to a
desired position.
The valve is manually controlled by tensioning of a cable (such as a Bowden TM
cable) connected
to the release plate 106 in response to actuation of the hand actuator 107 (in
the case of members
200a, 200b, this would be actuators 201a, 201b respectively).
[00127] Alternatively, such extendible support members can be lockable helical
springs or
a ratchet mechanism.
[00128] The seat 14 is coupled to the chair frame 12 such that the vertical
distance
accommodates a suitable floor to knee height for bariatric patients using the
chair. For example,
CA 02501419 2005-03-18
the seating surface 20 of the seat 14 at the front edge 24 of the seat 14 is
disposed above the
reaction surface 8 (see Figure 2) by a vertical distance of 21 inches. As a
further example, the
vertical distance is 23 inches.
[00129] Referring to Figures 1, 2, 13 and 14, the backrest 16 includes a
backrest frame 30
and a backrest front surface 32. In the illustrated embodiment, the backrest
frame 30 is coupled
to the seat frame 18. It is understood that it is not necessary to couple the
backrest frame 30 to
the seat frame 18, and that coupling between the backrest frame 30 and the
chair frame 12 may
be effected directly with the chair frame 12 independently of the seat frame
18. However, where
it is desired to facilitate pivotal movement between (i) the combination of
the seat 14 and the
backrest 16, and (ii) the chair frame 12 (ie. tilting of the seat 14) as it is
in the preferred
embodiment, the backrest frame 30 is coupled, and more particularly, pivotally
coupled to the
seat frame 18.
[00130] The backrest frame 30 is pivotally coupled to the seat frame 18 at
each of the
upper seat rails 84a, 84b, so as to facilitate pivotal movement (ie. movement
into various
positions of inclination) of the backrest 16 relative to the seat 14 and the
chairframe 12. In order
to facilitate pivotal movement of the seat 14 and backrest 16 (ie. movement
into various
positions of seat tilt) relative to the chair frame 12, the backrest frame 30
is pivotally coupled to
the seat frame 18. Pivotal coupling of the backrest frame 30 to the seat frame
18 enables
movement of the backrest from one position of inclination (or "recline")
relative to the seat 14
and the chair frame 12 to another position of inclination (ie. changing the
desired degree of
backrest inclination).
[00131] The backrest frame 30 is formed of two unitary spaced apart side
structures 34a,
34b comprising a plurality of elongated bar or tube members. For example, the
tube members
are 304 stainless steel, one inch diameter, 16 gauge (0.065 inch wall
thickness) tubes.
[00132] Each of the unitary side structures 34a, 34b includes a respective one
of main tube
members 36a, 36b. Each of the main tube members 36a, 36b is pivotally coupled
proximate the
CA 02501419 2005-03-18
36
bottom end thereof to a respective one of the upper seat rails 84a, 84b of the
seat frame 14, at a
position forwardly disposed of the rear end of a respective one of the upper
seat rails 84a, 84b.
The pivotal coupling between each one of the members 36a, 36b and a respective
one of the rails
84a, 84b is effected by a respective bolt extending through a respective pair
of aligned apertures,
one of the respective pair of aligned apertures being provided in a respective
one of the rails 84a,
84b and the other of the respective pair of aligned apertures being provided
in a respective one of
the members 36a, 36b. This effects pivotal coupling of the backrest 16 to the
seat 14.
[00133] Each of the members 36a, 36b extends upwardly from the seat frame 14.
Each of
the main tube members 36a, 36b is contoured to facilitate the desired shaping
of the backrest
support surface 32, as is further described below. The main tube members 36a,
36b are joined
together at or proximate their respective upper ends by a substantially
horizontal top member 38
extending between the main tube members 36a, 36b. A substantially horizontal
cross member 40
is also provided and extends between the main tube members 36a, 36b and below
the top
member 38. The cross member 40 is pivotally coupled to one end of each of the
extendible/retractable members 202a, 202b (see Figure 4). This effects pivotal
coupling of the
extendible/retractable support members 202a, 202b to the backrest 16. As well,
hand levers
associated with operation of the extendible/retractable members 202a, 202b,
are also mounted to
the cross member 40. The cross member 40 also can be used as a stroller-style
push handle for a
caregiver to pmpel the chair 10. The cross member 40 is supported by a pair of
spaced apart
cross brace members 42a, 42b extending from the top member 38, and is also
supported by a pair
of reinforcing tubes 44a, 44b, where each of the reinforcing tubes 44a, 44b is
coupled to and
extends upwardly from a respective one of the main tube members 36a, 36b.
[00134] Positioning of the backrest 16 in various positions of inclination
relative to the
seat 14 is enabled by the extendable/retractable support members 202a, 202b.
The support
provided by the extendible/retractable support members 202a, 202b is
adjustable, in that the
support members 202a, 202b can be locked in a first position, and then
released to permit
extension or retraction of the support members 202a, 202b so that the desired
degree of backrest
inclination can be changed, and then locked again once the backrest 16 is
positioned at the
desired degree of inclination. This facilitates changing of the desired degree
of backrest
CA 02501419 2005-03-18
37
inclination, while enabling support of the backrest 16 upon the backrest 16
being positioned to
the desired degree of inclination.
[00135] In this respect, the extendible/retractable support members 202a, 202b
are in the
form of a pair of gas springs is provided on the chair frame to exert an
upward force on the
backrest to thereby resist a downward weight of a chair occupant. A suitable
gas spring is a
BLOC-O-LIFT locking gas spring using a Bowden cable system, as manufactured by
Stabilus
GmbH. A detailed drawing of an embodiment of the extendible/retractable
support members
202a, 202b is provided in Figure 17. The general operation of the
extendible/retractable support
members 202a, 202b is the same as that described above for
extendible/retractable support
members 200a, 200b, with the exception that actuation of the members 202a,
202b is effected by
hand actuators 203a, 203b, respectively.
[00136] The backrest front surface 32 is configured for receiving and
supporting at least a
portion of the upper torso of the chair occupant. Like the seating surface 20,
the front surface 32
of the backrest 16 can be a continuous or a discontinuous surface, so long as
the front surface 32
performs the function of providing the necessary support to the chair
occupant. In the illustrated
embodiment, the backrest front surface 32 includes a plurality of spaced apart
vinyl straps
coupled to each of and extending between the tube members 36a, 36b. An
exemplary vinyl strap
is an extruded vinyl strap (1.5 inches wide, 0.13 inches thick, with a convex
radius along its
width) manufactured by Twitchell Corporation.
[00137] The backrest front surface 32 includes an upper backrest front surface
46 and a
lower backrest front surface 48. The lower backrest front surface 48 is
recessed relative to the
upper backrest front surface 46 in order to accommodate the lower torso of a
bariatric patient
who is occupying the chair 10. The space 52 within the recess is configured so
as to
accommodate and receive soft tissue in the gluteal region (ie. a "gluteal
shelf') of the chair
occupant where such soft tissue has become displaced rearwardly as a result of
the chair
occupant being seated in the chair. The desirability of accommodating a
gluteal shelf is
pronounced with bariatric patients, where the presence of a gluteal shelf is
particularly
significant when a bariatric patient is disposed in a seating position.
Without providing any
CA 02501419 2005-03-18
38
space in a chair for accommodating the gluteal shelf, seating of a bariatric
patient in a chair can
be relatively uncomfortable.
[00138] In this respect, the backrest 16 includes a backrest front support
surface 32
including an upper backrest front surface 46 and a lower backrest front
surface 48, the lower
backrest front surface 48 being recessed from, and merging with the upper
backrest front surface
46 at a merged front surface 50. An upper backrest front merging surface 4602
extends
upwardly from the merged front surface 50, and a lower backrest front merging
surface 4802
extends downwardly from the merged front surface 50. The point of merger
between the lower
backrest front surface 48 and the upper backrest front surface 46 is defined
by a point of
inflection at the merged front surface 50. The merged front surface 50 is
substantially disposed
in a horizontal plane 1801 (see Figures 18 and 19). "Substantially disposed in
a horizontal
plane" means that the merged front surface 50 may or may not be disposed
entirely in the
horizontal plane, and that if not so disposed, various portions of the merged
front surface may
vary from being disposed at and/or slightly above andlor slightly below the
horizontal plane. If
there is deviation from the horizontal plane, such deviation is minor and will
not be sufficiently
significant so as to noticeably reduce the comfort of the chair occupant.
[00139] A portion 4604 of the merging surface 4602 extending upwardly from a
portion of
the merged front surface 50 (see Figure 20D) is tangent to a merging surface
plane 1003. A
portion 4804 of the merging surface 4802 extending downwardly from a portion
of the merged
front surface 50 is tangent to a merging surface plane 1005. Each of the
merging portions 4604,
4804 is disposed in a vertical plane 1019 having a normal axis 1021 which is
perpendicular to
the normal axis 1023 of a plane tangent 1025 to the most forwardly disposed
front surface 1027
of the backrest front surface 32 (see Figures 20B and 20C). The plane 1803 has
a front face
which defines angle 91 relative to and above the plane 1805 (see Figure 20A).
The angle B1 is at
least than 10 degrees. For example, the angle B, between 10 degrees and 60
degrees. As a
further example, the angle B ~ is 30 degrees.
[00140] Where either of the merging surface portion 4604 or the merging
surface portion
4804 is a discontinuous portion, such portion 4604 or 4804 is defined by an
imaginary planar or
substantially planar surface extending upwardly or downwardly from the merged
front surface 50
CA 02501419 2005-03-18
39
and to an adjacent physical backrest front surface 32 portion (such as a vinyl
strap, in the case
where the backrest front surface 32 includes spaced-apart vinyl straps, as
described above).
[00141 ] The lower backrest front surface 48 extends upwardly relative to and
substantially
from the seating surface 20 of the seat 14, and merges with the upper backrest
front surface 46 at
the merged front surface 50. "Substantially from the seating surface 20" means
that the surface
48 may or may not be joined to the surface 20. If the surface 48 is not joined
to the surface 20,
the space between the surface 48 and the surface 20 is relatively small and
not sufficiently
significant so as to noticeably reduce the comfort of the chair occupant. For
example, the space
is not so large as to permit the gluteal shelf of the chair occupant to become
wedged between
surfaces 48 and 20.
[00142] The backrest surface 32 includes a top edge 47 and side edges 46a, 46b
(see
Figure 19). The side edges 46a, 46b are joined by the top edge 47. It is
understood that any of
the top edge 47 or the side edges 46a, 46b can be continuous or discontinuous.
In this respect,
any of these edges can include discontinuous portions so long as such edges
define the perimeter
of the backrest front surface 32.
[00143] A length of the backrest surface 32 is defined as any distance of the
backrest
surface 32 (including any discontinuous portions of the surface 46) between
the merged front
surface 50 and the top edge 47 and along any vertical plane 1008 having a
normal axis 1009 that
is perpendicular to the normal axis 1011 of a plane 1013 tangent to the most
forwardly disposed
front surface 101 S of the backrest front surface 32(see Figures 21 and 22). A
width of the
backrest surface 32 is defined as any distance of the backrest surface 32
(including any
discontinuous portions of the surface 46) between the side edges 46a, 46b of
the backrest surface
32 and along any horizontal plane 1017 (see Figures 23 and 24).
[00144] In the illustrated embodiment, the upper backrest front surface 46,
extending from
the merged front surface 50, is substantially planar. "Substantially planar"
means that the upper
backrest support surface 46 may or may not be planar. If the surface is not
planar, the deviation
from planar is minor and not sufficiently significant to be noticeable to the
chair occupant, and
CA 02501419 2005-03-18
such deviation may be the result of imperfections introduced during the
manufacturing process
of the chair or its individual components.
[00145] The upper backrest front surface 46 includes an upper backrest front
surface
portion having a minimum width and a minimum length. In this respect, the
width and /or the
length may not be the same across the entire upper backrest front surface
portion but, rather, may
vary from a minimum to a maximum. In the illustrated embodiment, the upper
backrest front
surface portion is substantially planar and substantially rectangular.
"Substantially rectangular"
means that the upper backrest support surface 46 may or may not be
rectangular. If the surface is
not rectangular, the deviation from rectangular is minor and not sufficiently
significant to be
noticeable to the chair occupant, and such deviation may be the result of
imperfections
introduced during the manufacturing process of the chair or its individual
components. For
example, the upper backrest front surface portion is the upper backrest front
surface 46, and has a
minimum length of at least 2 inches and a minimum width of at least 24 inches.
As a further
example, the minimum width is between 24 inches and 38 inches, and the minimum
length is
between 2 inches and 36 inches. As a further, further example, the minimum
width is 26 inches
and the minimum length is 12 inches.
[00146] The recessed disposition of the lower backrest front surface 48
relative to the
upper backrest front surface 46 defines a space 52 of substantially the same
cross-sectional area
across the merged front support surface 50. "Substantially the same cross-
sectional area" means
that the cross-sectional area may or may not vary by a small amount across the
merged front
support surface 50. If there are variances, such variances are minor and will
not be sufficiently
significant so as to noticeably reduce the comfort of the chair occupant.
[00147] A cross-sectional area 49 of the space 52 is defined, or is definable
upon relative
movement between the seat 14 and the backrest 16 (such as by tilting of the
seat 14 and/or
reclining of the backrest 16), in a vertical plane 1019 having a normal axis
1021 which is
perpendicular to the normal axis 1023 of a plane tangent 1025 to the most
forwardly disposed
front surface 1027 of the backrest front surface 32 (see Figures 25 and 26).
This cross-sectional
area of the space 52 is substantially defined or substantially definable
within the vertical plane
1019 between the lower backrest front surface 48, the seating surface 20 of
the seat 14, and a
CA 02501419 2005-03-18
41
plane 1020 tangent to a respective portion (ie. that portion disposed in the
vertical plane 1019) of
the upper backrest front merging surface 4602. Refernng to Figure 25, the
plane 1020 has a
front face which defines or is positionable (by tilting of the seat 14 and/or
reclining of the
backrest 16) to define an angle B3 relative to and above a horizontal plane
1807, and the seat 14
is positioned so as to provide a substantially horizontal seating surface. The
angle 93 is between
80 degrees and 153 degrees. In the embodiment illustrated in Figures 25 and
26, the angle B3 is
97 degrees. Where the seating surface portion 2001 is a discontinuous portion,
the seating
surface portion 2001 is defined by an imaginary planar or substantially planar
surface extending
between adjacent physical seating surface portions, (such as vinyl straps,
where the seating
surface 20 includes spaced-apart vinyl straps, as described above). The term
"substantially
defined or substantially definable", as used above with respect to the cross-
sectional area of the
space 52, means that the measurable space between these components is an
approximation of the
actual area of the space 52 available to receive the above-described gluteal
shelf, and that the
measurable space may or may not deviate slightly from the area of the actual
space 52. If there
is deviation, such deviation is minor and will not be sufficiently significant
so as to reduce the
comfort of the chair occupant. The cross-sectional area is at least 30
inches2. For example, the
cross-sectional area is between 30 inches2 and 100 inchesz. As another
example, the cross-
sectional area is 40 inches2. The space 49 is provided for receiving excess
flesh of a bariatric
patient who is seated in the chair.
[00148] As used herein, the term "a substantially horizontal seating surface"
describes the
nature of the seating surface provided by the seat 14 when the seat 14 is in a
certain position.
When a human is seated in the chair 10 when the seat 14 is in this position,
the virtual plane
which intersects the body of the seated human, from the knees to the hips, is
horizontal or
substantially horizontal.
[00149] One aspect of space 52 is the depth of the recess. The upper backrest
front
surface 46 includes an upper front surface portion 54, and the lower backrest
front surface 48
includes a lower front surface portion 56. The upper front surface portion 54
of the upper
backrest front surface 46 is disposed, or is positionable to be disposed (for
example, by tilting of
the seat 14 and/or reclining of the backrest 16), forwardly of the lower front
surface portion 56 of
CA 02501419 2005-03-18
42
the lower backrest support surface 48 by a horizontal distance 1039, wherein
each of the upper
front support surface portion 54 and the lower front surface portion 56 is
disposed in a vertical
plane 1019 having a normal axis 1021 which is perpendicular to the normal axis
1023 of a plane
1025 tangent to the most forwardly disposed front surface 1027 of the backrest
front surface 32
(see Figures 27 and 28). A plane 1041 tangent to the portion 54 of the upper
backrest front
surface 46 has a front face which defines or is positionable (by tilting of
the seat 14 and/or
reclining of the backrest 16) to define an angle B4 relative to and above a
horizontal plane 1043
(see Figure 29). The angle 94 is at least 85 degrees. For example, the angle
94 is between 85
degrees and 120 degrees. The illustrated angle B4 is 95 degrees (see Figure
29). The horizontal
distance 1039 is at least 3 inches. For example, the horizontal distance 1039
is at least 4 inches.
As a further example, the horizontal distance 1039 is between 3 inches and 8
inches. In yet even
a further example, the horizontal distance is between 4 and 8 inches. As a
further, further
example, the horizontal distance is 3 inches. The depth of the recess is
characterized by the
horizontal distance 1039 and is provided for receiving excess flesh of a
bariatric patient who is
seated in the chair 10.
[00150] The depth of the recess can also be defined relative to a portion of
the merged
front surface 50. A portion 1002 of the merged front surface 50 is disposed
forwardly, or is
positionable to be disposed forwardly (for example, by tilting of the seat 14
and/or reclining of
the backrest 16), of a lower backrest front surface portion 56 by a horizontal
distance 1045,
where each of the portion of the merged front surface 50 and the lower front
surface portion 56 is
disposed in a vertical plane 1019 having a normal axis 1021 which is
perpendicular to the normal
axis 1023 of a plane 1025 tangent to the most forwardly disposed front surface
1027 of the
backrest front surface 32 (see Figures 30 and 31). A plane 1051 (in this case,
plane 1051 is the
same plane as plane 1025) is tangent to the portion of the merged front
surface 50 disposed in the
plane 1019. The plane 1051 has a front face which defines or is positionable
(for example by
tilting of the seat 14 and/or reclining of the backrest) to define an angle BS
relative to and above a
horizontal plane 1043. The angle 95 is at least 80 degrees. For example, the
angle BS is between
80 degrees and 115 degrees. In the illustrated embodiment, 95 is 90 degrees
(see Figure 32). The
horizontal distance 1045 is at least 3 inches. For example, the distance 1045
is at least 4 inches.
As a further example, the distance 1045 is between 3 inches and 8 inches. In
yet even a further
CA 02501419 2005-03-18
43
example, the horizontal distance 1045 is between 4 inches and 8 inches. In a
further, further
example, the horizontal distance is 3 inches.
[00151 ] Another aspect of this space 52 is the height of the recess. The
height of the
recess is, generally, the distance between a portion 1002 of the merged front
surface portion 50
and a portion 21 of the seating surface 20 immediately below the merged front
support surface
portion 50. This distance is more particularly defined as the distance 1059
between a portion
1002 of the merged front surface 50 and a portion 21 of the seating surface
20. Each of the
merged front surface portion 501 and the seating surface portion 21 is
disposed in a vertical
plane 1019 having a normal axis 1021 which is perpendicular to the normal axis
1023 of a plane
1025 tangent to the most forwardly disposed front surface 1027 (which, in this
case, is the same
as merged surface portion 1002) of the backrest front surface 32 (see Figure
34). The seating
surface portion 21 is also disposed in a plane 1051 tangent to the merged
front surface portion
1002. Refernng to Figure 33, the plane 1 OS 1 (which, in this case, is the
same as plane 1025) has
a front face which defines or is positionable (for example, by tilting of the
seat and/or reclining
of the backrest) to define an angle B2 relative to and above a horizontal
plane 1075, and the seat
14 is positioned so as to provide a substantially horizontal seating surface.
The angle 92 is
between 70 degrees and 133 degrees. (see Figure 33). In the embodiment
illustrated, the angle
92 is 90 degrees (see Figure 33). Where the seating surface 20 includes
discontinuous portions
(see above), it is understood that the seating surface portion 21 may, in
fact, be a discontinuous
portion. Where the seating surface portion 21 is a discontinuous portion, the
seating surface
portion 21 is defined by an imaginary planar or substantially planar surface
extending between
adjacent physical seating surface portions, (such as vinyl straps, where the
seating surface 20
includes spaced-apart vinyl straps, as described above). For example, the
distance 1059 is at
least 8 inches. As a further example, the distance 1059 is at least 10 inches.
As a further, further
example, the distance 1059 is between 8 inches and 13 inches. In yet even a
further example,
the distance 1059 is between 8 inches and 18 inches. In yet even a further,
further example, the
distance 1059 is 13 inches. The merged support surface 50 and the seating
surface portion 21 are
either spaced apart relative to one another by the distance 1059, or are
independently
positionable (for example, by movement of the backrest 16 or the seat 14
relative to the other,
such as by tilting of the seat 14 and/or reclining of the backrest 16) to
become spaced apart
CA 02501419 2005-03-18
44
relative to one another by the distance 1059. This aspect of the space 52
assists in providing
room for receiving excess flesh of a bariatric patient who is seated in the
chair 10.
[00152] The recess extends from the merged surface portion 50 for a continuous
distance
of at least 12 inches along the merged surface portion 50. For example, the
continuous distance
is 26 inches. As another example, the continuous distance is between 12 inches
and 38 inches.
In one embodiment, the depth of the recess is substantially the same along
this continuous
distance, and the height of the recess is substantially the same along this
continuous distance.
[00153] With respect to the depth of the recess, "substantially the same"
means that the
depth may or may not be the same along the merged front support surface
portion. If there are
differences, such differences are minor and are not sufficiently significant
so as to noticeably
reduce the comfort of the chair occupant.
[00154] With respect to the height of the recess, "substantially the same"
means that the
height may or may not be the same along the merged surface portion. If there
are differences in
height, such differences are minor and are not sufficiently significant so as
to noticeably reduce
the comfort of the chair occupant.
[00155] With respect to the depth of the recess along the merged front surface
50, for
example, the merged front surface 50 includes a merged front surface segment
2002. The upper
backrest front merging surface 4602 of the upper backrest front surface
extends upwardly from
the merged front surface 50 and a lower backrest front merging surface 4802 of
the lower
backrest front surface 48 extends downwardly from the merged front surface 50,
such that the
upper backrest front surface 46 merges with the lower backrest front surface
48 at the merged
front surface 50. Each portion of the upper backrest front merging surface
4602 is disposed with
a respective portion of the lower backrest front merging surface 4802 in a
respective vertical
plane 5000, wherein the respective vertical plane 5000 has a respective
vertical plane normal
axis 5002 which is perpendicular to the normal axis 1023 of the plane 1025
tangent to the most
forwardly disposed front surface 1027 of the backrest front surface 32. Each
portion of the upper
backrest front merging surface is tangent to a respective upper backrest front
merging surface
plane and the respective portion of the lower backrest front merging surface
is tangent to a
CA 02501419 2005-03-18
respective lower backrest front merging surface plane. The respective upper
backrest front
merging surface plane has a front face which defines an angle 96 relative to
and above the
respective lower backrest front merging surface portion plane, wherein the
angle 66 is at least IO
degrees. For example, the angle 66 is between 10 degrees and 60 degrees. As a
further example,
66 is 30 degrees. Each portion of the merged front surface segment 2002 is
disposed with a
respective portion of the lower backrest front surface 48 in a respective one
of the vertical planes
5000. Each portion of the merged front surface segment is tangent to a
respective merged front
surface segment portion plane, wherein the merged front surface segment
portion plane has a
front face which defines or is positionable (by seat tilt and/or back recline)
to define an angle B~
relative to and above a horizontal plane, wherein 9~ is at least 80 degrees,
such as 90 degrees.
For example, 9~ is between 80 degrees and 115 degrees. Each portion of the
merged front
surface segment 2002 is disposed forwardly, or is positionable to be disposed
(for example by
tilting of the seat 14 and/or reclining of the backrest 16) forwardly, of the
respective portion of
the lower backrest front surface 48 by a horizontal distance 6000 of at least
3 inches. For
example, the horizontal distance 6000 is between 3 inches and 8 inches. As a
further example,
the horizontal distance 6000 is at least 4 inches, such as between 4 inches
and 8 inches. As a
further, further example, the horizontal distance 6000 is 3 inches. The
segment 2002 has a width
6002 of at least 12 inches. For example, the width 6002 of the segment 2002 is
26 inches. As
another example, the width 6002 of the segment 2002 is between 12 inches and
38 inches.
[00156] For example, with respect to the depth along the merged front surface
segment
2002 having portions 2004, 2006 in respective vertical planes 5102, 5202
(vertical planes 5000
include planes 5102, 5202), and referring to Figures 35 to 39, each of
portions 4604, 4606 of the
upper backrest front merging surface 4602 is disposed with a respective
portion 4804, 4806 of
the lower backrest front merging surface 4802 in a respective one of the
vertical planes 5102,
5202 (see Figures 35 and 36), wherein each of the respective vertical planes
5102, 5202 has a
respective vertical plane normal axis 5104, 5204 which is perpendicular to the
normal axis 1023
of the plane 1025 tangent to the most forwardly disposed front surface 1027 of
the backrest front
surface 32 (see Figure 36). Each of the portions 4604, 4606 is tangent to a
respective upper
backrest front merging surface plane 4608, 4610 (in this case, planes 4608 and
4610 are the
same), and each of the portions 4804, 4806 is tangent to a respective lower
backrest front
CA 02501419 2005-03-18
46
merging surface plane 4808, 4810 (in this case, planes 4808, 4810 are the
same). Refernng to
Figure 37, the respective upper backrest front merging surface portion plane
4608, 4610 has a
front face which defines an angle B6 relative to and above the respective
lower backrest front
merging surface portion plane 4808, 4810, wherein the angle B6 is greater than
10 degrees. In
Figure 37, the angle 86 is 30 degrees. Each portion 2004, 2006 of the merged
front surface
segment 2002 is disposed with a respective portion 4812, 4814 of the lower
backrest front
surface in a respective one of the vertical planes 5102, 5202. Referring to
Figure 38, each
portion 2004, 2006 (only portion 2006 is shown in Figure 38) is tangent to a
respective merged
front surface segment plane 2018a, 2018b (only plane 2018b is shown in Figure
38). The
respective merged front surface segment portion plane (ie. plane 2018b) has a
front face which
defines or is positionable (for example, by seat tilt and/or back recline) to
define an angle 6~
relative to and above the horizontal plane 2020 which is greater than 80
degrees, such as 90
degrees (shown). Referring to Figure 39, each portion 2004, 2006 is disposed
or is positionable
to be disposed (for example by tilting of the seat 14 and/or reclining of the
backrest 16)
forwardly, of the respective portion 4812, 4814 (only portion 4814 is shown in
Figure 39) of the
lower backrest front surface 48 by a horizontal distance 6000 of at least 3
inches.
[OOI57J With respect to the height of the recess across the merged front
surface segment
2002, each portion of the merged front surface segment 2002 is disposed, or is
positionable to be
disposed (for example, by tilting of the seat 14, or reclining of the backrest
16), above a
respective portion of the seating surface 20 by a vertical distance of at
least 8 inches, wherein
each portion of the merged front surface segment 2002 and the respective
seating surface portion
is disposed in a respective one of the vertical planes 5000. For example, the
vertical distance is
between 8 inches and 18 inches. As a further example, the vertical distance is
10 inches. Each
portion of the merged front segment 2002 is tangent to a respective merged
front segment
portion plane. The respective seating surface portion 20 is also disposed in
the respective
merged front surface segment plane. The respective merged front surface
segment plane has a
front face which defines or is positionable (by seat tilt and/or back recline)
to define an angle 98
relative to and above a horizontal plane, where the angle 6g is between 70
degrees and 133
degrees, and the seat 14 is positioned so as to provide a substantially
horizontal seating surface.
CA 02501419 2005-03-18
47
[00158] For example, with respect to the height of the recess across the
merged front
support surface segment 2002 having portions 2004, 2006 in the vertical planes
5102, S 104
(vertical planes 5000 include planes 5102, 5104), and referring to Figures 35
and 40, each
portion 2004, 2006 (only portion 2006 is shown in Figure 40) of the merged
front surface
segment 2002 is disposed, or is positionable to be disposed (for example, by
tilting of the seat 14,
or reclining of the backrest 16), above a respective portion 2202, 2204 (only
portion 2204 is
shown in Figure 40) of the seating surface 20 by a vertical distance 6002 of
at least 8 inches,
wherein each portion 2004, 2006 of the merged front surface segment 2002 and
the respective
seating surface portion 2202, 2204 is disposed in a respective one of the
vertical planes 5102,
5202 (see Figure 35). Each portion 2004, 2006 is tangent to a respective
merged front surface
segment portion plane 2018a, 2018b. The respective seating surface portion
2202, 2204 is also
disposed in the respective merged front surface segment plane 2018a, 2018b
(only plane 2018b
is shown in Figure 40, and this is tangent to portion 2006). Refernng to
Figure 40, the respective
merged front surface segment plane 2018a, 2018b has a front face which defines
or is
positionable (by seat tilt and/or back recline) to define the angle 9g
relative to and above the
horizontal plane 2020, wherein the angle B8 is between 70 degrees and 133
degrees, and the seat
14 is positioned so as to provide a substantially horizontal seating surface.
In Figure 40, angle Bg
is 90 degrees.
[00159] With respect to the cross-sectional area of the space of the recess
across the
merged front surface segment 2002, in each of the vertical planes 5000, a
respective two-
dimensional space is disposed in the respective vertical plane and is defined,
or is definable upon
positioning of the seat 14 relative to the backrest 16 (for example, by
tilting of the seat 14 and/or
reclining of the backrest 16), between: (i) the lower backrest front surface
48, (ii) the seating
surface 20, and (iii) the respective upper backrest front surface merging
portion plane (which is
tangent to the upper backrest front surface merging portion disposed in the
respective vertical
plane 5000). The respective upper backrest front surface merging portion plane
has a front face
which defines or is positionable (by seat tilt and/or back recline) to define
an angle B9 relative to
and above a horizontal plane, wherein the angle 99 is between 80 degrees and
153 degrees, and
the seat 14 is positioned so as to provide a substantially horizontal seating
surface. The space
CA 02501419 2005-03-18
48
has an area of at least 30 inches2 . For example, the space is between 30
inches2 and 100 inches2.
As a further example, the space is 40 inchesz.
[00160] For example, with respect to the cross-sectional area 4900 of the
space of the
recess across the merged front surface segment 2002 having the portions 2002,
2004 in the
vertical planes 5102, 5104 (vertical planes 5000 include planes 5102, 5104),
and referring to
Figures 35 and 41, a respective two-dimensional space is disposed in the
respective vertical
plane and is defined, or is definable upon positioning of the seat 14 relative
to the backrest 16
(for example, by tilting of the seat 14 and/or reclining of the backrest 16),
between: (i) the lower
backrest front surface 48, (ii) the seating surface 20, and (iii) a respective
upper backrest front
surface merging portion plane 4608, 4610 (only plane 4610 is illustrated in
Figure 41, see also
Figure 35). Referring to Figure 41, the respective upper backrest front
surface merging portion
plane 4608, 4610 has a front face which defines or is positionable (by seat
tilt and/or back
recline) to define the angle 99 to and above the horizontal plane 2028,
wherein the angle 99 is
between 80 degrees and 153 degrees, and the seat 14 is positioned so as to
provide a substantially
horizontal seating surface. In Figure 41, the illustrated angle 99 is 97
degrees.
[0016I] Optionally, a headrest 3000 may be provided, and releasably coupled to
the
backrest frame 30. The headrest is single axis height adjustable with the
option of either a
formed acrylonitrile-butadiene-styrene (ABS) head support or a contoured
closed cell
polyurethane foam head support.
[00162] The legrest 300 is pivotally mounted to the seat frame 18 at the posts
82a, 82b
(see above discussion). The legrest 300 includes a leg support member 302 and
a foot support
member 304. The leg support member 302 depends downwardly from the posts 82a,
82b and is
configured to support the calves of the occupant of the chair 10. The foot
support member 304
extends forwardly from the leg support member 302 and is configured to support
the feet of the
occupant of the chair 10. The legrest 300 is moveable by and supported in an
elevated position
by a pair of extendible/retractable members 306a, 306b, similar to the
extendible/retractable
members 204a, 204b, but cab be rated with a lower exertion force. Each of the
extendible/retractable members 306x, 306b is pivotally coupled at one end to
the legrest 300. In
particular, each of the members 306a, 306b is coupled to a respective one of
the arms 308a, 308b
CA 02501419 2005-03-18
49
extending rearwardly from the leg support member 302 of the legrest 300 by a
respective bolt
extending through a respective pair of aligned apertures, one of the
respective pair of aligned
apertures being provided in a respective one of the members 306a, 306b and the
other of the
respective pair of aligned apertures being provided in a respective one of the
arms 308x, 308b.
Each of the members 306a, 306b is also pivotally coupled at a second opposite
end to the chair
frame 14. In particular, the second end of each of the members 306a, 306b is
pivotally coupled
to a respective one of the pairs of forks 94a, 95a and 94b, 95b (see Figures
1, 2, and 4) by a
respective bolt extending through a respective set of three aligned apertures,
one of the
respective pair of aligned apertures being provided in a respective one of the
members 306a,
306b and the other two being provided in each of a respective one of the pairs
of forks 94a, 95a,
and 94b, 95b.
[00163] The members 306a, 306b enable positioning and support of legrest 300.
Extension of the members 306a, 306b urges the legrest 300 to rotate in an
upwardly and
forwardly direction, causing elevation of the feet of an occupant of the chair
10, and also causing
extension of the calves of an occupant of the chair.
[00164] A hand actuator 310 is mounted to the lower rail 93a, and coupled to
the
extendible/retractable members 204a, 204b, to effect unlocking of the
extendible/retractible
members 204a, 204b, and thereby effect pivotal movement of the legrest between
various
elevated and non-elevated positions. Operation of hand actuator 310 to effect
actuation of the
members 204a, 204b is similar to the operation of actuators 201a, 201b.
[00165] The chair 10 is particularly useful for seating of bariatric patients.
In this respect,
any of the above-described embodiments of the chair 10 can be used for the
seating of persons
having a body weight of at least 300 pounds.
[00166] Although the disclosure describes and illustrates preferred
embodiments of the
invention, it is to be understood that the invention is not limited to these
particular embodiments.
Many variations and modifications may occur to those skilled in the art within
the scope of the
invention. For definition of the invention, reference is to be made to the
appended claims.
