Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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DESCRIPTION
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TITLE :
"Chair with raisable seat, particularly for theaters"
BACKGROUND OF THE INVENTION
The present invention relates to chairs of which
the seat is raisable, and more particularly to chairs of
this type designed for theaters.
In a theater, of course, the minimum distance
between chairs of two successive rows is governed by safety
standards. This distance is reckoned between the most pro-
jecting part of a chair of a given row with respect to the
backrest of the chair of the preceding row. It is therefore
essential, in order to be able to install the maximum num-
ber of chairs in a theater of given size, for the seat to
be raisable as much as possible against the backrest.
The minimum overall dimension is determined by
the length of the armrests designed in vlew of comfort if
the raised seat is entirely received between these armrests.
Chairs comprising two lateral legs to which are fixed two
hinge casings generally have this minimum overall dimension
determined by that of the armrests. However, the mounting
of seat assemblies of this type is complex and the number
of parts to be adjusted important. Moreover, the lateral
position of the legs can constitute a constraint for the
spectators and the appearance thereof is unattractive.
These drawbac~s have been avoided by chairs with
raisable seats for which the support means comprise a single
central leg, such as that described in French patent
N 2 155 042.
In this case, a single hinge casing is fixed to
the leg, and the seat is connected to the casing through
its rear edge.
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However, the overall dimension of these chairs
is relatively large, since the rear of the seat cushion
abuts against the backrest is raised position so that the
front edge of the seat projects distinctly forward of the
end portion of the armrest. Here the overall dimension
which must be satisfied to respect the safety standards
is hence determined, not by the armrests, but by the raised
seat.
In addition, considering the distance between
lo the hinge axis and the center of gravity of the seat, a
very powerful return spring is necessary to obtain auto-
matic raising, and the hinge casing supporting considerable
forces, it is of very heavy construction. The large return
force necessary generally involves the use of a helical
spring mounted around the hinge axis and working in torsion.
This type of use causes fairly rapid fatigue of the spring,
which, associated with the contingent wear of the cushions,
results in a raised positiGn less and less high with time
as well as variations in the raised position over a row.
These variations constitute a threat to safety, detract
from the appearance and entail upkeep costs.
Finally, in known chairs with a raisable seat,
the hinge casings are welded to the support means or fixed
to the latter at a well-determined angle with respect to
its axis. The assembly of the support means and the casing
must therefore be adapted to the slope of the floor on
which the chair must be fixed, in order that the slope of
the seat may correspond to the conformation of the theater.
If on delivery, there appears a difference between the
theoretical and the actual slopes, the whole stock o
support means and casings of all the chairs must be changed
or chocks must be used, enormously complicating installa-
tion. On the other hand, the angle formed with the floor
by the axis of the support means varies with the theater,
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and if a support cover is required, lt must be manufactured
to order.
GENERAL DESC~IPTION OF THE INVENTION
To avoid these various drawbacks, an object of
the invention is to provide a chair with a ralsable seat
whose overall dimension is minimal, mounting simple, mecha-
nism light, robust and reliable, aesthetic appearance favo-
rable, comfort optimal and a1aptationto a floor slope easy.
The invention therefore provides for this purpose
a chair comprising a support means supporting a backrest,
a hinged seat and possibly armrests, said support means
including a unit which, seen in profile, has a general
shape of an upwardly-open U connected through its web to
a stay fixed to the floor, one of the limbs being situated
at the back and bearing the backrest, the other limb being
situated at the front and bearing the seat through a hinge,
the hinge axis being spaced from the rear end of the seat
so that a portion of the latter is received between the
limbs of the ~ when it is raised, wherein a leaf spring is
fixed to the front limb of the generally ~-shaped unit,
and cooperates with a lever-forming element fixed to the
seat so as to urge it towards its raised position.
According to another advantageous feature of the
invention, the generally U or V-shaped unit comprises a
single part of stamped sheet-metal.
According to a further advantageous feature of
the invention, the support means comprises a central leg
fixed to the floor and to the upper end of which is remo-
vably fixed, said generally ~-shaped unit.
BRIEF DESCRIPTION OF THE DRAWINGS
Other features and advantages of the invention
hill appear from the following description of a preferred
embodiment explained with reference to the accompanying
drawings, in which :
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Figure 1 shows a chalr according to the invention
seen in profile, with the seat raised ;
Figure 2 shows the chair of Figure 1 also in
profile, with the seat lowered ;
Figure 3 is a vertical section of the chair
through the middle plane ;
Figure 4 shows diagramatically in partly exploded
perspective a detail of the chair seen from below ;
Figure 5 shows a view from below of the seat of
the chair ;
Flgure 6 shows in perspective the leg of the
chair with the supports of the backrests and of the
armrests ;
E'igures 7, 8 ancl 9 show the adaptation of the
leg ar.c' of its cover to a floor of given slope.
DESCRIPTION OF PREFERRED EMBODIME~TS
A chair 1 according to t~.e invention is shown
as a whole in Figures 1 and 2 seen in profile. Its support
means comprises a leg 2 at the top of which is fixed an
iron fitting 3 which has, seen in profile, an upwardly-open
general U-shape. A seat 4 is hinged to the limb or winq 3a
of this iron fitting, whilst the limb or wing 3b is adapted
to receive a backrest 5 and armrests 6 are fixed thereto.
The leg 2 comprises a shaft 8 of metal tubing
with rectangular cross section whose lower end is cut at
right angles and welded to a plate 9 of sheet metal, design-
ed to be fixed to the floor by means of screws. A cover 10,
of plastics material, for example injection-molded, conceals
the whole of the leg 2. The upper end of the shaft 8 is cut
at an angle determined as a function cf the slope of the
floor and of the desired inclination of the seat 4, as
indicated in Figures 7, 8 and 9. A metal plate 11 is welded
to this end, and also comprises threaded orifices for fixing
the iron fitting 3.
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The latter i5 obtained by stamping an approxima-
tely rectangular sheet metal plate. The rear wing or limb
3b of this generally U-shaped structure is substantially
longer -than the front wing or llmb 3a, and both are orient-
ed upwards and slightly inclined outwardly.
The later~l edges 3c are folded back to a right
angle towards the inside of the ~ in order to stiffen the
iron fitting. Web 3d connecting the two limbs 3a and 3b is
almost flat and fixed by screws 12 to the plate 11.
An axle support 13, of acetal resin, for example,
provided with side-notches 14 forming bearings, cap the
upper edge of the wing 3a. To the practically flat lnner
face of the latter is fixed a leaf-spring 15 by means of
a screw 16 passing through the wing 3a and screwed intc a
cage-nut 17 fast to the leaf spring 15. The upper end 15a
of the latter is curved back towards the front to form a
semi-cylindrical latching portion with axis parallel to
the axis of the notches 14 but slightly shifted, situated
opFcsite a cut-out 18 formed on the up~r edge of the wing
3a and masked by the support 13.
A fastening fork of the backrest 5 is fixed by
means cf screws (not shown) on the inner surface of the
upper end of the rear wing 3b of the structure 3. It
comprises a sheet metal plate 19 to the lateral ends of
which are welded to parallel square tubec 2G extending
obliquely upwards. An adjusting screw 21 only the head of
which is visible from outside the structure 3, is screwed
into a threaded orifice 22 formed in the plate 19 to permit
adjustmert of the inclination of the tubes 2C, and hence
that of the backrest 5 fitted on these tubes 20.
A bridging member 23 is welded to the rear upper
end of the lateral edges 3c, and supports rigld steel arms
24, to ~hich are fixed iron fittings 25 to which are attach-
ed the armrests 6.
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A metal lug 26 is welded to the middle of the
lower surface of the member 23 and serves as a stop for
the seat 4 when it is lowered.
The latter comprlses essen-tially a foam cushion
27 covered with upholstery 28 and fixed to a rigid case 29,
for example of plastics material molded by inj~ction under
pressure. At the rear of the case 29 is provided a rectan-
gular cavity to receive a plate 30 for hinging the seat,
of stamped sheet-metal. Its lateral ~dges 30a are flanged
and their rear ends 30b are folded back against the rear
edge of the case to which they are fixed by screws 31.
An extension 30c from plate 30, covered with
rubber or other elastic material .at its end, projects
rearwards and upwards as shown in Figure 3.
An axle 32, constituted by a round steel rod
bent into a crank shape is welded transversly to the lateral
edges 30a.
This ax1e is slightly spaced vertically from the
plate 30, and is at a distance from the edge of the seat
of about a quarter of the total length of the latter (see
Figure 4). The central portion 32a of this axle is parallel
to its lateral portions 32b but slightly eccentric rearwards
and downwards when the seat is lowered.
These lateral portions 32b are received in notches
25 14 of the suFport 13, whilst the portion 32a is in engage-
ment with the hook-shaped portion 15a of the leaf-spring 15.
The latter therefore impresses a rotary torque on the axle
32 in anti-clockwise direction (seen in Figure 3) so that
the seat 4 is always urged towards its raised position.
3G The seat 4 is hence hinged around the axle 32,
and its extreme positions are determined on the one hand
by the extension 30c and the lug 26 for the lowered position,
and on the other hand by this same extension 30c and a foam
pad 33 fixed, for example, by glueing to the bottom of the
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iron fitting 3, as regards the raised position. In the
latter position, the rear portion of seat 4 is received
between the wings of the iron fitting 3 ~Figure 1). Conse-
quently, the seat 4 can be turned back without obstacle
against the b2ckrest S between the armrests 6, and the
maximum longitudinal overall dimension of the chair is
limited to a distance d (Figure 1) definec between the
rear énd of the backrest 5 and the front end of the arm-
rests 6. Moreover, the stop 26 and the extension 30c form
lC an accurate and reliable stop d~vice for the raised posi-
tion, so that this position does not vary in the course
of the use of the chair.
On the other hand, the position of the axle 32
spaced from the rear edse of the seat 4, considerably
1~ red~ces the return torque necessary tc raise the seat 4,
since the seat portion situated behind the axle 32, with
its hinge plate 30, forms a ccunterweight when the seat
is raising.
The spring therefore exerts less force on the
support means and on the hinge which can thus be ligh~ened
with respect to prior art structures.
In addition, a leaf spring 15 with a small range
of movemer,t may be employed, which simplifies ccnstruction
and mounting of the chair, since it is fixed and tensioned
by a single screw 16. Also, the r~liability and life of the
whole of the chair is increased, in spite of the lighter.ing
of the parts.
In modifications which are not shown in the
drawings, the U-shaped iron fitting 3 may be replaced by
two lndependent metal members extending approximately
vertically to the front and to the rear of the support
means. These members can then be fixed to a floor plate
with a certain separation between them to define the space
into which the rear portiGn of seat 4 can be retracted.
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In the same way, various structures may be
adopted for the seat and the backrest ; the case 2, for
example, can be replaced by a rigid structure provided
with a vlsible covering also on its inner surface.
