Note: Descriptions are shown in the official language in which they were submitted.
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FIELD OF THE INVENTION
The present invention relates to an improved
device for inclining, in adjustable and conjugate
manner, the backrest and seat of an armchair which
are articulated on each other and on the ground-
engaging elements of this armchair, of which the
armrests are articulated on the backrest and connec-
ted to the legs via racks.
BACKGROUND OF THE INVENTION
i0 Such a known device is illustrated in French
Patent No. 2 596 261 which teaches -that the geometri-
cal pivot axis of the backrest on the seat lies
behind the geometrical pivot axis of the backrest
on the ground-engaging elements and located horizon-
15 tally with respect to the preceding axis when the
backrest is inclined in mid-position. In this way,
the end positions of the pivot pin of the backrest
on the seat are substantially vertical with respect
to each other. Consequently, the horizontal projec-
20 tion of the path of this pivot pin of the backreston the seat is relatively little and, as a result,
it may be absorbed by the clearances of all the
pivot pins of the armchair. Under these conditions,
the inclination of the backrest is accompanied
25 by an inclination of the seat with a virtually
negligible horizontaL translation of this seat,
with the result that the mobile assembly of the
front pivot pin of the seat on the ground-engaging
elements, which was necessary in the prior embodi-
30 ments, may be eliminated.
However, this particular arrangement of thepivot pins presents the drawback of over-stressing
the racks of the armrests of the armchair when
a person is sitting therein, being given that the
35 weight of the body tends to lower the backrest.
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Furthermore, in order to modify the adjustment
of the inclination of the backrest, the person
sitting down must lean forwards, on the one hand
to unlock the racks and, on the other hand, to
move the backrest without losing his balance and
tipping backwards.
It is an object of the present invention to
overcome these drawbacks whilst conserving the
advantage of the known device set ~orth hereinabove
whereby any mobile assembly of the front pivot
pins may in fact be eliminated.
SUMMARY OF THE INVENTION
To that end and in accordance with the inven-
tion, the geometrical pivot axis of the backrest
on the seat lies in front of the geometrical pivot
axis of the backrest on the ground-engaging elements,
and located, when the backrest is in completely
erect position and in completely lowered position,
respectively below and above the horizontal line
passing through this geometrical pivot axis of
the backrest on the ground-engaging elements.
The end positions of the geometrical pivot
axis of the backrest on the seat are substantially
symmetrical with respect to the horizontal line
passing through the geometrical pivot axis of the
backrest on the ground-engaging elements.
This improved device of the invention may
be applied to the V-shaped ground-engaging elements
of the foldable armchair illustrated in French
Patent No. 2 596 261 mentioned above, which ground-
engaging elements comprise, on each side, a front
leg and a rear leg whose upper ends are pivoted
on each other and provided with a finger cooperating
with the rack of the corresponding armrest. In
~5 this application, the pivot pins of the seat and
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of the backrest are borne by these front legs and
rear legs, respectively, whilst the pivot pins
of the seat on the backrest lie in front of the
pivot pins of the backrest on the rear legs.
The improved device of the invention may also
be applied to the rigid ground-engaging elements
oE an armchair, which ground-engaging elements
are constituted by two lateral bows of which each
comprises a front branch or leg and a rear branch
or leg connected by a stretcher at mid-height and
integral with an upper median bend provided with
the finger cooperating with the rack of the corres-
ponding armrest. In this particular application,
the pivot pins of the seat and of the backrest
are respectively borne by the front legs and the
stretchers, whilst the pivot pins of the seat on
the backrest are located in front of the pivot
pins of the backrest on the stretchers.
The improved device according to the invention
may also be applied to the other types of armchair
made of plastics material, for example to those
comprising ground~engaging elements foldable in
X form, on condition, however, that at least one
additional piece, such as a connecting rod, is
provided and suitably disposed.
BRIEF DESCRIPTION OF T~E DRAWINGS
The invention will be more readily understood
on reading the following description with reference
to the accompanying drawings, in which:
Figure 1 is an elevational view showing, seen
from inside, the right-hand side of a foldable
armchair with ground-engaging elements in V-form,
to which armchair the device of the invention is
applied.
Figure 2 is a diagram showing, on a larger
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scale, the advantages of the kinematics of this
device.
Figure 3 is a view similar to Figure 1 illustra-
ting the application of the device of the invention to an armchair having rigid ground-engaging elements.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring now to the drawings, Figure 1 shows
a foldable armchair with ground-engaging elements
in V-form, whose seat and backrest are adjustable
10 in inclination in conjugate manner. The armchair
is advantageously made of injection-moulded plastics
material.
As shown, this armchair presents a normal
seat level and the adjustments enable the occupant
15 to be in a more or less rearwardly reclining position.
In fact, such an armchair is intended for
relaxing and sun-bathing. Consequently, the level
of its seat is lower and, in sun-bathing position,
the seat and the backrest are in line with each
20 other, substantially horizontally (Figure 2).
The armchair comprises a backrest 1 and a
seat 2 presenting lateral ears 3, 4 respectively,
of which two are integral with aligned pins 5 which
pass through holes made in the two ears, in order
2~ to constitute articulations located at the base
of the backrest and to the rear of the seat.
The armchair also comprises ground-engaging
elements 6 constituted by two front lateral legs
7 joined by means of a low stretcher 8 and by two
rear lateral legs 9 likewise joined by means of
a low stretcher 10. On each side, the front and
rear legs 7 and 9 are joined, at their upper end,
by a pivot pin 11.
Seat 2 is supported at the front by the front
legs 7 by means of aligned pins 12. Backrest l
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is supported at its base by the rear legs 9 by
means of aligned pins 13.
Finally, the armchair comprises two lateral
armrests 14 extending between the backrest 1 and
the top of the ground-engaging elements 6 to ensure
stability of the armchair, comfort for the person
sitting in it, and adjustment of the inclinations.
To that end, each armrest 14 is connected at the
rear to the backrest 1 by means of aligned pins
15 and, in its median zone, to the ground-engaging
elements 6 by means of a rack 16 moulded with the
armrest in question and whose notches 17, four
in the example shown, although this number is non-
limiting, are capable of cooperating selectively
with a finger 18 projecting from a lug 19 on the
corresponding rear leg 9
As shown in Figures 1 and 2, the geometrical
axis of pins 5 for seat 2 to pivot on backrest
1, lies in front of the geometrical axis of pins
13 for backrest 1 to pivot on the rear legs 9.
Furthermore, if the horizontal plane P passing
through the geometrical axis 13 (Figure 2) is con-
sidered, the end positions 5b and 5h of the geometxi-
cal pivot axis 5 joining seat 2 to backrest 1 lie
below and above this plane P, the positions 5b
and 5h of the common articulation corresponding
respectively to the position of the completely
erect backrest 1 (shown in solid lines in Figure
2) and to the position of the completely lowered
backrest (shown in broken lines in Figure 2). The
plane Q joining pivot axis 5 in these positions
5b and 5h is substantially vertical, this reducing
to a minimum the camber f of the circular path
T joining said positions 5b and 5h, i.e. of the
path of axis 5 when the backrest 1 pivots by the
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maximum angular amplitude about axis 13 of the
rear legs.
As camber f is very little, the functional
clearances in the articulations are sufficient
to compensate it, this making it possible to dispense
with using a mobile acsembly, for example by connec-
ting rod, of the pin 12 for seat 2 to pivot on
front legs 7.
Furthermore, and especially, these kinematics
make it possible to distribute the Eorces so that
the weight of the person sitting down has for its
effect to balance the system and thus to allow
this person to unlock the racks of the armrests
and to modify the inclination of the backrest without
having to get up or to lean too far forwards.
The device described hereinabove is applicable
to other types of armchairs and in particular to
the one shown in Figure 3.
This Figure 3 shows an armchair made of plastics
material with rigid ground-engaging elements, consti-
tuted by two lateral bows 20. Each bow comprises
a straight front leg 21 and an arcuate rear leg
22 integral with each other by an upper bend 23
and a stretcher 24 at mid-height. The ground-engaging
elements also present, moulded with the bows 20,
low stretchers 8 and 10 joining together the front
legs 21 and back legs 22, respectively.
Iike the one of Figure 1, this armchair compri-
ses a backrest 1, a seat 2 and armrests 14. Backrest
1 is borne by stretchers 24 via pivot pins 13 joining
this backrest to lugs 24 on these stretchers 24.
Backrest 1 is fur1:her coupled via pins 15 to armrests
14, which are adjustably joined to ~he bends 23
of the bows 20 by means of racks 16 on said armrests
cooperating selectively with fingers 18 projecting
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from lugs 19 on said bends. Seat 2 is joined by
pivot pins 12 to the front legs 21 and by pivot
pins 5 to backrest l.
In this armchair according to Figure 3, with
rigid ground-engaging elements, pivot pins 5 and
13 are disposed in the same manner and for the
same result as the pins, bearing the same references,
of the armchair of Ftgure l with ground-engaging
elements in V form. Consequently, the comments
lO set forth hereinbefore with reference to Figure
2 for the armchair of Figure 1 are valid for the
armchair according to Figure 3.
The device employed and illustrated in this
Figure 2 is, of course, applicable to all other
types of armchairs, on condition that additional
modes of connection are provided where necessary.
Furthermore, the pivot pins described may
be replaced by any other equivalent means.
