Note: Descriptions are shown in the official language in which they were submitted.
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ARMC~AIR WITH TILTABLE SE~T
TECHNICAL FIELD
This invention relates to an armchair having a tiltable
seat to provide aid to an occupant in rising from the seat.
BACKGROUND ART
Chairs having tiltable seats are known in the art. For
example, a chair havfng a seat in which the tilting move-
ment is actuated by spring-loading designed specifically
for a particular user is known. It is also known to pro-
vide a chair with a tiltable seat in~which the tilting
1~ movement is pneumatically or electrically controlled.
However, these seats tend to be expensiveJ bulky and
difficult to operate by infirm or elderly persons.
OISCLOSURE OF THE INVENTION
The present invention seeks t o overcome the disadvantages
of prior constructions by providing a chair with a tiltable
seat which is actuated by a relatively simple mechanism~
and which utilizes the normal force which an occupant
èxerts in rising from the séat.
To this end, the invention provides an armchair having a
seat tiltable relative to a ~fixed ~frame of the ~chair to
provfdè aid to~an occupant in~ri5ing from the chalr,; the ;
seat being tilt~able~ from a~lowè~red~po~s1t~i~on to a~ raised
2`5 pQsftion~by a lever mechani~5m pro~vi~de;d beneath the sea`t,
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characterised in that the lever mechanism is operatively
connected to at least one pivotal arm assembly of the chair
and is actuated by downward movement of that arm by force
exerted thereon by the occupant in rising from the chair.
An embodiment of the invention will now be described, by
way of example, with reference to the accompanying drawings
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a perspective view of an armchair according to
the invention;
FIGURE 1A is an exploded view of the main structural com-
ponents of the chair;
FIGURE 2 is a side view of one side frame member of the
chair showing the seat in a tilted and raised position;
FIGURE 3 is a side view similar to FIGURE 2 but showing the
2û seat in a lowered position as normally occupied.
FIGURE 4 is a part-sectional perspective view of a pivotal
arm assembly incorporating locking means by which the tilt-
ing mechanism is held locked relative to the fixed frame of
~5 the chair;
FIGURE 5 is a detailed cross-sectional view of the locking
means shown in locked condition and
3û FIGURE 6 is a view similar to FIGURE 5 but showing the
locking means lA a ~eleas d condi ~ion
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BEST MODE FOR CARRYING OUT THE INVENTIO_
Referring to the drawings, the armchair 70 is of modular cons-
truction of which the main structural components comprise a
pair of similar side frames 12, 14 respectively, inter-
connected and spaced apart by a tiltable seat pa~ 16;
a back frame 18, and a pair of pivotal arm assemblies 20,
22 respectively, each of which actuates a seat tilting
mechanism such as mechanism 24.
Side fram~ 14 comprises a main upright strut 26, a foot 28
integral with upright strut 26 and a forwardly projecting
1û support member 30 also integral with the upright strut
i~termediate its ends. Side frame 12 is of similar cons-
truction.
The back frame 18 is a simple rectangular frame comprising
longitudinal and transverse frame elements 32,34 and 36,38
respectively. The longitudinal frame elements are formed
with fastening locations 'l' at which the side frames are
connected to the back frame by suitable fasteners at fixing
locations 'f'. The transverse frame element 38 is displac-
ed forwardly of the plane containing the other frame
elements and thereby provides a step 's' on which the rear-
most part of the seat pan is supported when the seat is in
its lowered lsubstantially horizontal) position. The back
frame is in-filled by a suitable material, which may be
attached to the longitudinal frame elements as shown in
order to provide the chair back 40.
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The seat pan ?6 also comprises a generally rectangular
frame comprising longitudinal and transverse frame elements
42,44 and 46,48, respectively. The forward transverse
frame element 48 is displaced rearwardly and below the
longitudinal frame elements so that the frame in-fill mat- ¦
erial 50 is wrapped over the leading edge of the seat to
aid comfort of the user. The forward end of each of the
longitudinal frame ~elements is furnished with a journal
bush 52 and 54, respectively, by which the leading edge of
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of the seat is pivotally connected to the tilting mechanism
24.
- The seat tilting mechanism will now be described with
S reference to mechanism 24 associated with side frame 14, it
being understood that a similar mechanism is associated
wt-th the other side frame 12.
Mechanism 24 comprises a main tilting lever 56 which is
pivotally moun~ted at 'P' intermediate its ends to svpport
member 30 of side frame 14. One end of lever 56 carries
a stub shaft 58 which engages beneath seat pan longitudinal
frame element 44.
The stub shaft 58 may be replaced by a rod which connects
together the main tilting 2evers of both tilting mechanisms
and which extends across the seat pan 16. The opposite end
of main tilting lever 56 is pivotally mounted at 60 to the
lower end of a connecting strut 62 of pivotal arm assembly
22. The upper end of strut 62 is hinged to the forward
end of pivotal arm 64 of the assembly 22 by means of a
hinged connection 66. The rearward end of pivotal arm 64
is pivotally mounted to the side frame 14 by pivotal
connection 68.
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In order to provide simultaneous lifting and forward
movement of the seat pan 16,: a main lifting lever 70 has
one of its ends pivotally Journalled to the leading edge of
the seat frame by means of a pivotal connection to journal
bush 54 and has its opposite end pivotally and slidably
mounted to the support member 30 adjacent upr~lght strut 26
by means of pivot 72 mounted within sllder 74. The main
lifting lever 70 is~ interconnected with the~main til;ting
lever 56~ ntermediate th;eir~ ends by ~means ~of p~ivotal
connection 76.
The seat tilting:mechanism Z4 is actuated by pivotal move-
ment of the arm assembly 22~::as w~ :now ~be~ described.
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The connecting strut 62 of the arm assembly 22 is of hollow
construction and houses a reciprocal actuator push rod 78
which slides in a through bore 80 of the strut 62. The
upper end of push rod 78 abuts the undersurface of an
actuating button 82 within button recess 84. The lower end
of the push rod is formed to provide an inclined face 86
which cooperates with detent 88 having a cunieform recess
90 in its mid-section. Detent 88 is slidably accommodated
within a blind bore 92 extending transversely of the strut
1û adjacent its lower end. The detent has a locking nose
portion 94 which normally protrudes proud of the mouth of
blind bore 92 and engages in a recessed step 96 provided at
the forward end of support member 30 thereby to hold the
pivotal arm assembly locked to the support member against
pivotal movement.
In order to release strut 62 to permit pivotal movement
of the arm assembly 22 the push rod is caused to move down-
wardly whereby the inclined surface 86 acts on the opposit-
ely inclined surface 98 of the detent mid-section and
forces the detent to slide inwardiy of blind recess 92
against the force of compression spring 100. Thus, the
nose portion 94 is retracted out of engagement with the
recess step 96 to unlock the pivotal arm assembly.
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The actuating button extends through an aperture 102 provi-
ded at the forward end of pivotal arm 64 so that an exposed
portion of the button stands proud of the pivotal arm 64
and is depressed to cause a downward movement of the push
3û rod.
The lower end of strut 62 is formed with a stepped portion
7û4 which seats in an oppositely stepped portion provided
in the lower forward end of support member 30 when the arm
assembly is in its locked condition.
The other arm assembly 20 is slmilarly constructed.
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When both arm assemblies are in their locked positions,
the pivotal arms thereof are in a substantially horizontal
position and the connecting struts are in an upright posi-
tion as shown in solid lines in FIGURE 3. Moreover, in
this condition the seat pan 16 is in its lowered position
i.e substantially horizontal and the main levers of the
tilting mechanism 56 and 70 are in folded condition
adjacent the inner faces of the support members of their
respective side frames. Hence, the chair may be used as a
19 normal arm chair.
In order to benefit from the aid a user derives in rising
from the chair by the tiltable seat, the occupant first
depresses the actuating buttons of each arm assembly
1~ simultaneously so as to unlock those assemblies. The
occupant thereafter actuates the seat tilting mechanism by
pushing downwardly on the forward ends of the pivotal arms
during rising and also shifts forwardly in the seat. This
is a quite natural movement normally affected in rising
from an armchair.
However, in the chair according to this invention, such
rising movement by the occupant operates the tilting
mechanism again referred to in relation to mechanism 24.
As the pivotal arm 64 moves downwardly about pivot 68,
connecting strut 62 pivots anti-clockwise about hinge 66
thereby causing the main tilting lever 56 to rotate clock-
wise about pivots 6û and 'P'. Thusj stub shaft 58 pushes
upwardly against the seat frame and in so doing executes
3~ a relative sliding movement with respect thereto travelling
forwardly of the seat frame. Thus,;the seat is caused to
. pivot about its journalled forward end e.g jounal bush 54
in a clockwise direction whereby the rear of the seat frame
is raised relative ~o its~front end.
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Since levers 56 and 70 are interconnected, clockwise
-i rotation of lever 56 also causes pivot 76 to shift~relatlve
to fixed pivot 'P' and thus the pivotal movement of lever
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56 is accompanied by a generally forward sliding movement
of pivot 72 relative to slider 74 during anti-clockwise
rotation o~ lever 70 about pivot 72. Thus, the leading
edge of the seat simultaneously is raised and moved forwar-
dly relative to the support member 30. Hence, the scissor-
like assembly of levers 56 and 70 is 'opened' when the
seat is in its raised and tilted condition.
When the occupant returns to the chair and sits upon the
seat, the occupants body-weight causes the seat to be
lowered thus 'closingl the scissor-like mechanism to its
initial position. ~he connecting strut detents automatica-
lly lock into the support mem6ers due to their spring
loaded bias and due to the ramp sur~a~e p-ovided 3t the tip
of the detent nose portion.
As shown in FIGURE 1 the feet of the side frames have
divergent forward facing portions to provide a stable base
for the chair. Further, this arrangement allows a user
having a walking aid to approach the chair more easily.
2û
In order to allow the seat to return gradually to its lowered
position a one-way damping device 'D', which may be a pneu-
matic piston and cylinder device is interconnected between
pivot 54 and 58 thereby to retard lowering movement of the
seat. It is to be understood that the relative ratios of the
lever sizes and their pivotal locations can be adjusted to
provide different tilt angles of the seat and to vary the
height to which the seat is raised. ~For example, where the
damping device 'D' is a pneumatic piston and cylinder device
3û the angle of inclination of the raised seat is arranged to be
less acute so that end 58 of the main tilting lever travels a
smaller distance relative to the seat frame.
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