Note: Descriptions are shown in the official language in which they were submitted.
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ELASTIC MEANS FOR ROLLING UP A ROLLER CURTAIN
BACKGROUND OF THE INVENTION
S The present invention relates to production of roller
curtains or the like, which are applied to windows for
darkening, for preventing insects from entrance, and the
like.
In particular, the present invention concerns
configuration of the curtain rolling up elastic means,
their supports, and the connection system between the
roller support shaft and the rolling up elastic means.
DESCRIPTION OF THE PRIOR ART
These curtains, commonly called roller or roll up
curtains, are usually wound on a roller, which is
rotatably supported, in horizontal position, inside a
box-like casing situated in the region of the window
20 inner upper edge.
The roller can rotate axially for curtain unrolling and
subsequent rolling up.
Amongst all the types of roller curtains, there are two
groups of them distinguished according to the unrolling
25 and rolling mechanism type. One of these types includes
elastic means, usually a helical spring situated inside
the winding roller and fastened thereto, so that
unrolling rotation determines its torsion and consequent
elastic reaction can be used later for rolling up the
30 curtain.
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The curtain is unrolled by directly pulling it downwards
and then suitable locking means keep it in the desired
position until it is to be rolled up.
Another type of curtain does not include elastic means
and is operated manually also for rolling it up.
A small pulley is fastened to the roller head and has a
suitably shaped groove into which an operating chain fits
for unrolling and rolling up the curtain.
In the first type of curtain, one end of the elastic
means is rigidly fastened to the roller while the other
end is fixed to the window frame, so that the elastic
means are stressed in relation to the curtain unrolling.
According to known, techniques, in order to avoid spring
undulation, one of its extremities is fastened to a
15 longitudinally moving element situated inside the roller,
which rotates along with the roller.
Nevertheless, it is obvious that in case of curtains of a
certain length, reaching the end of the unrolling stroke
will require a high number of turns of the roller, and
20 spring elastic reaction and torsional stress will be
considerable.
This fact provokes problem in dimensioning of the springs
to be used which anyway do not return an elastic reaction
that fits the necessary strength for rolling up the
25 curtain in a uniform way.
Moreover, the supports of the rolling up spring must be
adequate for the elastic reaction to be determined and
this increases the dimension of the supports and the
global cost of the curtain production.
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Furthermore, montage of the rolling up assembly is
complicated, since the assembly includes the coupling
element between the roller and one extremity of the
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rolling up spring, the spring, and a shaft which passes
through the whole roller and fastens the other extremity
of the spring to the casing containing the curtain.
All these elements must be assembled inside the roller
and adapted to its transversal dimension, which
corresponds to the curtain width.
Therefore, the spring tension problem becomes important
when a long and narrow curtain must be unrolled and
rolled up, because the length of the spring will not be
adequate and thus it will be excessively stressed.
In case of curtains operated completely manually, called
also friction curtains, the lack of the elastic reaction
determines the necessity of considerable strength for
rolling the curtain up, a strength which increases in
relation to the length of the curtain unrolled.
To cope with this problem, the diameter of the driving
pulley must be large to allow curtain rolling up and
unrolling with a reduced effort, also for reducing the
size of the operating chain. However, the support
20 dimensions must be determined on the basis of the torque
which is created in the regions of the ends of the
roller. This has effect on the global dimension of the
casing containing the curtain.
Another problem encountered with the conventional
25 friction curtain devices is that the unrolling and
rolling up device must have the possibility of being
positioned either on one side or on the other side of the
window frame to which the curtain is mounted, in
accordance with the features of the environment where the
30 curtain is mounted.
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To obtain this result two possible ways can be followed in the
prior art. According to a first way both the components of the
rolling up system and the components of the connection system
are produced in two mirror-like different series. The components
S of either one or the other series are used in accordance with
the necessity.
According to the second way only the rolling up spring are
produced in two diverse series, having the same elastic constant
but winding in opposite directions.
10 As it can be easily understood, this fact determines a
considerable problem, and production of the roller curtains in
both the ways as well as distribution and storing thereof cause
high costs. Also maintenance operation of the curtains produced
in both the ways just described is complicated and expensive.
15 The paten specification GB 222,936 to J. Hartley and G.R.
Thornborough, disclosed improved means for securing and mounting
spiral springs used in revolving shutters and the like. To
afford more power for rising or lowering the shutter, the
improved means include cylindrical cores or blocks made in two
20 (or more) diameters and each diameter is spirally grooved so as
to receive a respective spring.
This allows to mount two (or more) springs to roll up the
shutter, and the springs are connected to the roller at one
side, by means of a core, and to the internal shaft at the other
25 side, by means of a block.
The object of the present invention is to propose improved
elastic means, which return elastic reaction in a more gradual
way and adequately to the effective force necessary to roll up
the curtain as it is unrolled from the roller.
30 Another object of the present invention is to propose elastic
means of limited dimensions so as to form an assembly which can
be rapidly and easily introduced inside the roller independently
from the length of the roller. This is obtained by means of a
suitable coupling device, which not only locks one extremity of
35 the elastic means to the roller so as to load them elastically,
but also reduces the torsion entity, to which they are subjected
as the roller is rotated.
The previously mentioned features not only improve the curtain
working, but also reduce the global production cost.
40 Another object of the present invention is to improve the
connection means which join the elastic means to the roller and
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to the roller supporting shaft in a way such that mirror-like
relocation of the roll up device, on
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each side of the window to which the roller curtain is to
be mounted, becomes easy and quick, without any need of
replacement or double set production.
SUMMARY OF THE INVENTION
These objects are obtained by use of the elastic means
for automatically rolling up a roller curtain, or
respectively for compensating for the weight of friction
10 curtains during manual rolling up thereof, with the
roller rotatably supported in horizontal position by a
stationary frame, wherein the elastic means include a
plurality of helical springs, which at one extremity are
rigidly fastened to a common support connected to said
15 shaft, and with the other extremity of each helical
spring fastened to a respective support and constraint
element, geometrically coupled to the roller.
The common support is formed by a step tapered cylinder
defining stepped sections, with each spring press-fitted
20 to a corresponding section.
Each support and constraint element includes a cylinder,
to which a spring is fastened, a raised edge which
engages geometrically with the internal surface of the
roller, and a cavity made axially in the cylinder, into
25 which a spring of a smaller diameter enters.
The shaft is connected with the stationary frame by
interposition of a speed reducer which determines a
torsion entity of the elastic means reduced with respect
to the actual rotation of the roller.
30 The speed reducer, together with the group of springs,
their supports, the shaft and the external support
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cylinder body form a compact assembly, which is
introduced into the roller.
Geometrical connection between the shaft and the common
spring support is obtained by means of connection-driving
5 means including splines made on the shaft and matching a
splined hole made in the support so that the shaft can
slide therein thus allowing removal and relocation
thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
The characteristic features of the invention will be
pointed out in the following description, with particular
reference to the enclosed drawings, in which:
15 - fig. 1 shows an exploded view of a curtain rolling up
system, according to the present invention;
- fig. 2 shows a section view of a head of the roller
with joined thereto a coupling mechanism described in the
following;
20 - figs. 3 and 4 show two section views taken along planes
III-III and IV-IV of fig. 2;
- fig. 5 shows a section view of two non contiguous parts
of the roller equipped with rolling elastic means being
the subject of the present invention;
25 - figs. 6 and 7 show transversal section views of the
roller taken along planes VI-VI and VII-VII of fig. 5;
- fig. 8 shows a section view of a head of the roller,
with joined thereto the elastic means coupling mechanism
of a friction curtain;
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- figs. 9 and 10 show two section views taken along
planes IX-IX and X-X of fig. 2.
BEST MODES OF CARRYING OUT THE INVENTION
The rolling up elastic means, described in the following,
can be used with both types of curtains, either rolling
up with a rolling up spring or friction curtains. In the
latter case, the elastic means compensate for the curtain
10 weight .
Nevertheless, to simplify the description, the reference
will be made to the rolling up curtain using a rolling up
spring.
With reference to figures 1, 5, 6 and 7, the roller 19,
on which the curtain 20 is rolled up, is rotatably
supported in horizontal position, by a stationary element
35, to which one extremity of the elastic means is
connected by a shaft 2, extending inside the roller, via
a coupling reducer device 30, described in the following.
20 The other extremity of the elastic means 50 is fastened
directly to the roller 19 and is rotated along with the
roller, as described below.
The elastic means 50 include a plurality of helical
springs 26, 27, 28, e.g. three. Obviously, the number of
25 springs can be any, within the range imposed by the
dimensions of the roller 19 and the size of the springs
to be used.
In the region of a common end, the springs 26, 27, 28 are
rigidly fastened to a common support 15 connected to the
30 shaft 2. Geometrical connection between the shaft 2 and
the common spring support 15 is obtained by means of
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connection-driving means including splines made on the
shaft and matching a splined hole made in the support 15
which can thus slide along the shaft.
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With reference to fig. 5, the common support 15 includes
a step-tapered cylinder forming stepped sections 16, 17,
18. Each spring is press-fit to a corresponding section.
The other extremities of the helical springs 26, 27, 28
S are fastened to respective support and restraint elements
36, 37, 38 introduced inside the roller 19 in geometrical
coupling therewith.
Each of the support and restraint elements 36, 37, 38
includes a cylinder, on which a respective spring is
10 fastened, a raised edge 46, 47, 48 which engages
geometrically with the internal surface 19a of the roller
19 and of a cavity 38a, 37a made axially in the
respective cylinder 38, 37 so as to allow the passage of
a spring of a smaller diameter.
15 These elastic means allow to use springs of different
dimensions and different elastic constants instead of the
single spring used in traditional roller curtains.
Therefore, it is possible to determine selectively the
entity of elastic reaction of each spring, thus
20 adjusting the elastic reaction of the group of springs
more precisely.
An elastic reaction is thus obtained which is softer and
set more gradually during the curtain unrolling.
With separate support elements for each spring, it is
25 possible to mount springs very different in length, or
pre-load, e.g. one or more springs in opposite direction
with respect to the others, thus determining their
operation only from a predetermined point of the curtain
unrolling on.
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This result can be improved if the shaft 2 is fastened to
a reducer 30 which is connected to the stationary element
35 and to the roller 19.
The resulting advantage is that the elastic reaction of
the springs is kept within a more limited range of values
thus corresponding more precisely to the unrolled curtain
weight gradually increasing as the curtain unrolls.
With reference to figures from 1 to 7, the device 30
includes a cup element 1, partially introduced into a
10 head of the roller 19, so that its cavity is turned
outside.
The external surface la of the cup element 1 matches the
internal surface 19a of the roller 19, as appears evident
from figure 3, so that rotation of the roller determines
also rotation of the cup element 1.
The cavity lb of the cup element 1 features an internal
ring gear 21 and has a concentric through hole made in
its bottom, through which the shaft 2 passes freely.
The device includes also a plurality of planetary gears
3, supported, so as to engage the ring gear 21, by a
spider member, or planet carrier, 5 with a concentric
hole 5a, inside which the extremity of the shaft 2,
opposite to the one fastened to the elastic means 50, is
introduced with geometrical coupling.
25 The shaft is blocked inside the hole by fixing screw
means of known type, or by glue.
The planet carrier 5 is combined with a perforated plate
4 that keeps the planetary gears 3 in their positions on
respective support pins.
30 Finally, the roller is supported externally by a
cylindrical body 6, fastened in a firm position to the
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stationary element 35 by a geometrical coupling with its
shank 8.
The cylindrical body 6 is inserted into the cavity lb of
the cup element 1, with possibility of reciprocal
5 rotation, and features a toothed protrusion 7 extending
axially, which is introduced between the planetary gears
3, thus forming the sun gear of the planetary gear train
including, beside the toothed protrusion 7, the planetary
gears 3 and the internal ring gear 21, as is well seen in
10 fig. 3.
The so far described elements are housed in the cup 1
which is introduced in the head of the roller 19.
Figures 8, 9 and 10 show the same device mounted to a
friction curtain, which is unrolled and rolled up by a
15 chain 22, fitting into a shaped groove of a small pulley
9 made on the most external edge of the cup element 1.
Operation of the device will be described in the
following.
When the curtain is unrolled from the roller by the
20 direct action of a string which is pulled in the
direction T, see fig. 4 for the automatic rolling up
curtain, or by pulling a chain 22 mounted on the pulley 9
of the cup element 1, rotation of the roller 19
determines the torsion of the extremity of the elastic
25 means 50 fastened thereto, but at the same time, it
rotates also the cup element 1, so that the ring gear 21
determines rotation of the planetary gears 3 with respect
to a sun wheel formed by the toothed protrusion 7.
Consequently, the planet carrier 5 is rotated with
30 angular displacements reduced with respect to those of
the roller 19.
The planet carrier transmits the rotation movement to the
shaft 2, which acts on the springs 26, 27, 28 via the
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common support 15 with reduced entity with respect to the
rotation of the roller 19, that acts directly on the
support and constraint elements 36, 37, 38.
Since the rotation directions of these members are the
same, the elastic means 50 will be subjected to a reduced
torsional stress, that corresponds to the difference in
angular displacements, i.e. corresponds to the reduction
rate imposed by the coupling device 30.
All this allows to use the same torsional entity of the
elastic means 50 along an unrolling path more extended
than with the conventional curtain roll up devices.
This means that normal length curtains equipped with the
subject device will require a torsional stress reduced
with respect to curtains equipped with conventional roll
15 up devices.
The shaft 2 has a size such that its end remains near the
most external support and constraint element, and in this
point it is provided with a coaxial disc 11 or another
element of almost cylindrical section, which keeps the
shaft 2 concentric with respect to the roller 19.
A considerable advantage deriving from use of the group
of springs 50 co-operating with the elastic means
coupling device 30 lies in the possibility to reduce the
springs length.
25 This, together with the fact that the shaft 2 does not
pass through the whole roller as in traditional curtains,
allows to dramatically reduce the length of the whole
group and make it independent from the roller 19 length.
In fact, the coupling device 30 together with the elastic
means 50 and the shaft 2 form a compact and small group,
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which is introduced in the region of a head of any
winding roller, independently from its length.
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The other head of the roller 19 accommodates a cap 12,
rotatably mounted to a cylindrical support 13, featuring
a tang 14, similar to the shank of the cylindrical body
6, engaging with a corresponding receiving seat suitably
5 made in the stationary frame for supporting the roller
19.
The cap 12 carries means for reversible locking of the
curtain in any position which it must assume and maintain
when it is unrolled.
10 This allows to use the same rolling up mechanism for
curtains and rollers of different width, giving the
components bigger versatility.
Obviously, the compact form of the rolling up system
allows it to be applied also to friction curtains,
15 operated manually also for rolling up the curtain by
means of a chain 22 (fig. 10), acting in this case only
as compensation for the curtain weight which increases as
the curtain is unrolled from the roller 19.
The rolling up system of the present invention allows
20 easy and quick mirror-like relocation of the roll up
device, on each side of the window to which the roller
curtain is to be mounted. To re-locate the rolling up
device the following operations must be carried out.
Firstly, the coupling reducer device 30 is removed from
25 the shaft 2 so that the spider member 5 is set free and
taken away from the shaft 2. Also the pulley 9 is removed
from the shaft. Then, the shaft 2 is withdrawn from the
elastic means 50 with a simple sliding movement, so that
the shaft end 2a comes out beside the roller coupled
30 support cylinders 36,37,38.
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The shaft 2 is inserted again with the end 2a into the
elastic means 50 on the opposite side, i.e. into the
common support 15. Lastly, the pulley 9 and the spider
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support 5 can be mounted again onto the shaft 2, in the
region of the end 2a, that has taken the place of the end
2b of the shaft 2, which carries the coaxial disc 11.
Therefore, another advantage of the present invention is
that in friction curtains the roll up system can be
indifferently located either on the left or on the right
side of the curtain casing by simple relocation thereof,
without necessity of production of doubled set assemblies
which are to be chosen upon montage.
10 Also storing room of the necessary components is reduced
since the same assembly can be mounted with the roll up
system on one side or on the other side.
It is understood that the subject invention has been
described, with reference to the enclosed drawings, as a
15 mere, not limitative example, therefore possible variants
resulting from practice and use are protected by the
present invention as described above and claimed
hereinafter.
