Note: Descriptions are shown in the official language in which they were submitted.
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FIELD OF THE INVENTION
1 The present invention relates to a roller blind
and in particular a spring assembly for controlling
weighting of the roller blind.
BACKGROUND OF THE INVENTION
Roller blinds are very popular for industrial
use. However, one of the drawbacks of a conventional
industrial roller blind is that the blind, being of
substantial size, is often very heavy to rewind from a
lowered position.
In typical home style smaller roller blinds, a
coil spring is used as an automatic rewind for the blind.
A lock is provided to hold the coil spring in different
tensioning positions. The spring tension is substantially
greater than the weight of the blind so that as soon as
the lock is released the coil spring pulls the blind
upwardly. This type of spring actuated return is fickle
in that if the lock should release prematurely, the blind
virtually flies upwardly and can often unwind on its
mounting shaft. This type of an arrangement is not
suitable for a much heavier industrial blind.
A type of industrial blind control that is
available through General Clutch Corporation is one which
uses a spring clutch tightening as the blind is unwound
and loosening as the blind is lifted. However, there is
no spring assist in the lifting of the blind which is
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1 accomplished by hand through a chain drive. This
arrangement suffers from the drawback noted above, i.e.
the awkwardness of handling the weight of a large
industrial blind.
SUMMARY OF THE PRESENT INVENTION
The present invention provides a roller blind
construction which is not subject to uncontrolled blind
rewinding as found in small ho~e blinds but which does
include a spring assist not found in standard awkward to
use industrial blinds. More particularly, the roller
blind of the present invention comprises a flexible blind
windable on a rotatable blind mount for lowering and
raising the blind. The blind has a downward weighting
which increases as it is lowered, however the blind
construction further includes a counterbalancing coil
spring which produces an upward pull in direct relation to
and neutralizing that downward weighting without lifting
2~ the blind.
As a result of the counterbalancing, although the
blind is not actually lifted by the spring, it is
essentially weightless easily enabling lifting of the
blind by hand.
BRIEF DESCRIPTIûN OF THE DRAWINGS
The above as well as other advantages and
features of the present invention will be described in
greater detail according to the preferred embodiments of
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1 the present invention in which;
Figure 1 is a perspective view of a roller blind
construction according to a preferred embodiment of the
present invention.
Figure 2 is a section through the chain drive end
of the roller blind of Figure 1.
Figure 3 is an enlarged view of the chain and end
cap from the roller blind of Figures 1 and 2.
Figure 4 is an exploded perspective view showing
the end assemblies at opposite ends of the roller blind of
Figure 1.
Figure 5 is a further exploded perspective view
showing assembly of the blind components.
Figure 6 is a sectional view looking from the
front of the blind of Figure 1.
Figure 7 is a view similar to Figure 6 showing
tension adjustment for the coil spring of the roller blind.
Figure 8 is an enlarged perspective view of the
left end region of the shaft mount from Figure 7.
Figure 9 is a partially exploded perspective view
of the left end assembly of Figure 1.
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Figure 10 is a sectional view through the
assembled end cap of Figure 9 showing position of the
blind mount with the blind in a partially lowered position.
Figure 11 is a view similar to Figure 10 showing
the blind mount with the blind in a fully lowered position.
DETAILED DESCRIPTION ACCORDING TO THE PREFERRED
EMBODIMENTS OF THE PRESENT INVENTION
o Figure 1 shows a roller blind construction,
generally indicated at 1. This roller blind construction
includes a flexible blind 3, which winds and unwinds into
and out of a housing 5 containing the mounting components
for blind member 3.
More particularly and referring to Figure 5,
blind 3 is windably mounted on a roll-like blind mount 41
fitted over a supporting non-rotating shaft 7. Also
fitted over shaft 7 interiorly of the blind mount is a
20 coil spring 11.
Figures 4 and 5 show an end cap 23 for housing 5
and a blind movement and spring control assembly 26,
including a spring connector generally indicated at 12.
25 This spring connector has a threaded end 13 onto which end
15 of spring 11 threads and a mounting end 17, seen only
in Figure 4, which is rotatably coupled with assembly 26.
This control assembly comprises a main disk 19 fitted over
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the cylindrical inwardly projecting portion 25to the
interior of cap 23 and having a geared surface 21 for
engaging chain 37. Mounted to the inner surface of disk
19 are a series of mounting components 27 and 31. Each of
the mounting components 27 includes a pair of inwardly
projecting legs 29 while each of the mounting components
31 includes a pair of outwardly projecting legs 33
interlocking between legs 29 of adjacent mounting
components 27 as seen in Figure 4 of the drawings. Each
lo of the mounting components 31 further includes rubber-like
shock absorbers 35.
The blind movement and spring control assembly 26
is rotated for the winding and unwinding of the blind and
causes rotation of spring end 15 secured to spring
connector 12 while the other end of the spring is secured
against rotation as to be described later in detail.
Therefore, one end of the spring rotates with the blind
while the other end of the spring is fixed against
rotation-
31ind mount 41 is provided with inwardly directedwebs 43. These webs fit in the recesses between shock
absorbers 35 of mounting components 31 and the side walls
of mounting components 27. ûne of these recesses is
indicated at 36 in Figure 5. Therefore, by virtue of this
interlocking of the webs of the blind mount with the
assembly 26, the blind is wound and unwound by the blind
movement and spring control assembly.
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1 Figure 4 shows a second end cap 47 fitted to the
opposite end of housing 5 from cap 23. This end cap
includes a large central opening for rotatably receiving
the end of the blind mount and is provided with a brake
arrangement for adjusting the ease with which the blind
mount rotates within the housing. This brake arrangement
comprises a brake pad 49 having an inner surface contoured
to fit to the blind mount and an outer surface provided
with a leaf spring 51. Cap 47 includes an opening 48 for
receiving a set screw 53 which rides up against leaf
spring 51. The setting of screw 53 determines the amount
of pressure that the brake pad through leaf spring 51
applies on the outer surface of the blind mount.
Figure 8 shows the actual mounting of shaft 7
within the overall assembly. Here it will be seen that
the shaft includes a flattened end 9 which fits into a
corresponding opening of the end cap protrusion 25. This
fitting locks the shaft against rotation and since the
shaft is locked against rotation so is end 17 of the
spring where it is attached through spring connector 18 to
the shaft. The other end 15 of the spring is, as
described above, rotatable with winding and unwinding of
the blind through spring connector 12 rotatably coupled to
disk 19. Therefore, the spring is also wound and unwound
by lowering and raising the blind respectively to vary the
springs upward pull according to the degree to which the
blind is unwound. However, at the same time the downward
weighting of the blind varies according to the degree to
which the blind is unwound.
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1 The lowering and raising of the blind is done by
hand through chain 37. This chain fits upwardly through
end cap 23 at the two bottom openings 24a and 24b seen in
Figure 4 of the drawings and wraps around gear surface 21
on disk 19. Chain 37 includes one enlarged bead 39 which
acts as an end stop in that it will not fit up through
opening 24a in cap 23 and therefore determines the maximum
position to which the blind can be unwound.
The operation of the overall system is as
follows. With the blind totally raised, spring 11 is at
an initial preferably neutral, coil tension relative to
the blind mount and the roller blind. However, as the
blind is unwound the coil spring, being secured at one end
to rotate and being fixed at its other end against
rotation is wound up relative to the neutral setting as
the blind is unwound producing an upward lift on the
blind. However, at the same time, the blind as it is
unwound increases in downward weighting producing a
downward pull in the opposite direction to the upward lift
of the spring. For best utilization of the system, the
sprin~ tension is set such that it just offsets the down
weighting of the blind at all blind positions. Therefore,
although the spring provides a counterbalance, it does not
physically lift the blind. This is to be contrasted to
the home use blinds earlier described that require a lock
to hold the spring from automatically lifting the blind.
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1 The tension of the spring is, as seen in Figures
6 through 8, easily adjusted at its initial setting to
accomodate different blind weights. In Figure 6, shaft
end 9 through the spring loading on the shaft is forced to
lock in extension 25 on the inner surface of end cap 23.
However, as seen in Figure 7, through the use of an
appropriate tool, shaft end 9 is simply popped out of its
engagement with extension 25 and the shaft is then rotated
as shown to either decrease or increase the winding of the
spring. This is again achieved as the result of the
spring being connected at one end only to the shaft.
Although safety components such as the spring
tension and the brake are built into the blind, it is
still further provided with a shock absorbing feature the
components of which have been described above and the
operation of which is described having reference to
Figures 10 and 11 of the drawings. This shock absorber
feature is provided to prevent breakage of the chain used
to raise and lower the blind which is a common occurance
in other presently available roller blinds. Here it
should be noted that the chain control t using a large stop
ball such as ball 39 in the chain is common to the
industry and the breakage of the chain in prior art
structures occurs as a result of impact of that ball with
its stop guard when the blind moves abruptly to its
lowermost setting. However, in the present application
this impact is absorbed as shown in Figure 11 of the
drawings where although ball 39 comes up into contact with
the bottom of the end cap, the roller-like blind mount 41
is allowed to continue to rotate very slightly by
collapsing members 35 through blind mount webs 43 as
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seen in Figure 11. This absorbs the shock or impact which
would otherwise be placed on ball 39 used to stop the
downward momentum of the blind. Note Figure 10 shows the
blind as it is being lowered but prior to ball 39 running
5 Up against the bottom of end cap 23.
A further unique feature of the present design
can be seen in Figure 1 of the drawings showing the two
end caps 23 and 47. As will be further seen in Figure 4
o of the drawings, end cap 23 includes a center slot 24c
actually fitting around the end of the blind. End cap 47
has a similar construction. Accordingly, the end caps fit
to either side of the blind and act as a light block for
preventing outside light from passing around the end of
15 the blind
Although various preferred embodiments of the
invention have been described in detail, it will be
appreciated that variations may be made without departing
from the spirit of the invention or the scope of the
appended claims.
