Note: Descriptions are shown in the official language in which they were submitted.
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SHINGLE WITH REINFORCEMENT LAYER
Background of the Invention:
In the manufacture of shingles, it has been known that when shingles are
subjected to strong winds, the winds can engage the lower edges or tab
portions of the
shingles, and bend them upwardly.
On occasion, under strong winds, the tabs can bend upwardly in amounts
sufficient that the inherent, internal resistance to substantial bending and
perhaps
cracking, can be overcome, in that the mat that is formed internally of the
shingle, and
the asphaltic material on the surfaces of the shingle, may not be sufficient
to withstand
certain wind conditions.
Various approaches have been made to resist shingle failure via cracking and
the like,
not all with substantial success.
For example, strips of adhesive material along lower ends of tabs of shingle
have
been applied, which, when subjected to hot weather conditions, soften an
amount sufficient
that such adhesive will adhere to the next-subjacent shingle on a roof,
eventually harden
and thereafter resist upward deflection of shingle tabs under severe wind
conditions.
However, such adhesive sometimes dries out, or becomes brittle over time,
offering
reduced adhesion. In other cases, strong wind conditions can exist during high
temperature
situations when such adhesive located under tabs remains soft, and thus the
adhesive does
not function in its intended manner.
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Other approaches have resorted to thickening the mat and/or asphaltic
material, to
offer internal resistance to bending, but nonetheless, failures due to wind-
related bending
of tabs of shingle continue to exist.
Summary of the Invention:
The present invention is directed toward providing a shingle, wherein a
separate,
exterior reinforcement layer is provided outside the rear surface of the
shingle, with such
layer comprising a material that is not coated or covered by any thick layer
of asphalt or
the like.
Accordingly, it is an object of this invention to provide a novel shingle
having a
layer on the lower surface of the shingle, that comprises a reinforcing
material.
It is a further object of the invention to accomplish the above objects,
wherein the
reinforcement layer comprises a scrim material.
It is another object of this invention to accomplish the above objects,
wherein the
reinforcing material extends into either or both of the tab portion of the
shingle and the
headlap portion of the shingle.
It is a further object of this invention to accomplish the object above,
wherein the
reinforcing material extends into a nailing zone or other fastening zone of
the shingle
through which nails or other fasteners pass upon securing the shingle to a
roof.
It is a further object of this invention to provide a method of making
shingles in
accordance with the objects set forth above.
Other objects and advantages of the present invention will be readily
understood
upon a reading of the following brief descriptions of the drawing figures,
detailed
descriptions of the preferred embodiments and the appended claims.
Brief Descriptions of the Drawing Figures:
Fig. 1 is a rear elevational view of a shingle made in accordance with the
prior art.
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Fig. 2 is an illustration like that of Fig. 1, but wherein the shingle is
shown to have
a reinforcement layer applied to the rear surface thereof, in accordance with
the present
invention.
Fig. 2A is a right side view of the shingle of Fig. 2.
Fig. 3 is an illustration like that of Fig. 2, but wherein the reinforcement
layer
extends farther into the tab portion of the shingle than in the embodiment of
Fig. 2.
Fig. 4 is a side view of the shingle of this invention shown resisting torque
applied
to the tab portion of the shingle under a wind-lifting force that bends the
shingle
upwardly at approximately 450
.
Fig. 4A is a vertical sectional view of the shingle of Fig. 4, as applied to a
roof of
steep slope.
Fig. 5 is a graph showing an example of the absorption of wind-lifting torque
upon bending a particular weight of shingle through various angular degrees
and the
improvement of providing a reinforcement material in accordance with this
invention
under the same lifting conditions.
Fig. 6 is a view similar to that of Fig. 5, for a somewhat different weight of
shingle, and a different weight of mat for the shingle.
Fig. 7 is an illustration similar to that of Figs. 5 and 6 for a differently
constructed
shingle.
Fig. 8 is a graph similar to that of Fig. 7, for a shingle have a wider
reinforcement
layer.
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Detailed Descriptions of the Preferred Embodiments:
Referring now to the drawings in detail, reference is first made to Fig. 1,
wherein a
prior art shingle is illustrated as comprising a shingle generally designated
by the numeral
10, constructed as a mat of preferably fiberglass mesh, having asphalt, or
some other form
of bitumen material impregnated therein, and forming layers on each surface
thereof, with
a granular material on each exposed surface. On the upper exposed surface,
will be
granules of a size desired to resist sun and other weather conditions, and on
the opposite,
or undersurface 11, there will be preferably smaller granules of a mica, sand
or like
material, for example. The shingle 10 has a headlap portion 12 and a tab
portion 13,
having slotted openings 14 dividing the tab portion 13 into a number of
discrete tabs 15.
On the undersurface 11 there is provided preferably but optionally a sheet of
release paper
or tape 16, which is removed when the shingle is installed on a roof. but
which, for
stacking shingles for shipment prevents the shingle from sticking to a
subjacent shingle in
the stack, which subjacent shingle has a similarly located strip of adhesive
material, such
as more bitumen, extending longitudinally from edge 17 to edge 18, on the
front surface of
the subjacent shingle.
The basic shingle of Fig. 1 may be made in accordance with the teaching of US
patent
6,092,345. US patent 6.145,265, or US patent 5.822,943.
With specific reference to Figs. 2 and 2A, it will be sent that a shingle 20
is
presented, having a rear surface 21, with a release strip 26 running from left
to right across
the lower end of a headlap portion 22, between edges 27 and 28. and with the
tab portion
23 of the shingle 20 comprising a plurality of tabs 25 separated by vertical,
spaced apart
slots 24.
A nailing zone "N" exists on the front surface of the shingle 20, generally
located above
the release tape or strip 26, running between edges 27, 28 above the slots 24.
Essentially, the
shingle 20 is similar to that of the shingle 10 of Fig. 1, but with a
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reinforcement layer, preferably of fiberglass, of a width between
approximately 3 and
8cm, and preferably about 21/2 inches, that may comprise a scrim layer 29 is
added on the
rear 21 of the shingle 20, across the upper end of the tab portion 23 , and
across the lower
end of the headlap portion 22, as shown in Fig. 2, covering the area shown in
Fig. 2, as
well as the area disposed beneath the release strip 26, along the lower end of
the headlap
portion 22 between edges 27 and 28, as shown in Fig. 2. During the
construction of the
shingle of Fig. 2, the reinforcement layer 29 is thus applied before the
release tape 26 is
applied.
Thus, the reinforcement layer 29 may be a fiberglass scrim and will preferably
be
a woven construction, involving woven strands disposed at right angles to each
other,
with a preferred density of, for example nine strands in the vertical
direction and nine
strands in the horizontal direction per square inch of scrim (9x9 per in2).
With reference to Fig. 3, it will be seen that a shingle 30, much like the
shingle
20, is provided, having a rear surface 31, having a headlap portion 32 and tab
portion 33,
with the tab portion comprising a plurality of tabs 35 separated by slotted
openings 34,
with a release strip 36 extending between left and right edges 37 and 38, and
with a scrim
39 located beneath the release strip 36 as with respect to the embodiment of
Fig. 2, but
extending downwardly farther into the tabs 35, as shown, in that the scrim 39
is
essentially about 6 inches wide, running from the upper edge of the release
strip 36, into
the tabs, as shown.
It will be apparent that other lengths of scrim 29, 39, will be appropriate
depending upon the desired resistance to bending under wind conditions, as
will be
addressed hereinafter.
The scrim layers 29, 39, will not be coated with a bitumen or other asphaltic
material, nor will they have granules applied thereto, such that the filaments
of the scrim
29, 39, especially those extending vertically as shown in Figs. 2 and 3, can
resist bending
and resist failure in the form of the likelihood of forming horizontal cracks
across the
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upper end of the tab portion of the shingle, when the shingle is bent upwardly
within its
elastic limit under forces applied by winds or other upward lifting forces.
The scrim may have a density other than the 9x9 per in2. addressed above, such
as
but not limited to 8x8 per in2 or 7x7 per in2, and may be of various
compositions other
than fiberglass, such as polyester, polypropylene and/or nylon. In lieu of a
scrim, the
reinforcement layers 29, 39 may comprise woven or nonwoven thin fabric,
plastic film,
paper, parchment, foil or the like, either embedded in the asphaltic layer on
the rear of the
shingle or adhered to the rear of the shingle by an additional post-applied
thin layer of
asphaltic or non-asphaltic adhesive. The reinforcement layer 29, 39, will be
adhered to
the rear surface 21, 31 of the shingles of this invention, by means of any
suitable
adhesive, such as a bitumen or the like, or any other adhesive.
With reference now to Fig. 4, it will be seen that a roof 40 is fragmentally
illustrated, having a shingle 41 fastened thereto by means of a nail, staple,
42 or the like,
through the nailing or fastening zone of the shingle as described above with
reference to
Fig. 2, and therefore through the reinforcement layer 29. When wind forces
occur in the
general direction indicated by the arrow 43 in Fig. 4, such that they tend to
bend the tab
portion 44 of the shingle upwardly to an angle "a", as shown by the dotted
arrow 45, the
scrim 46 applied to the undersurface of the shingle 41 will tend to resist
upward bending
of the shingle tab portion 44, largely because of the resistance to such
bending that is
provided by the reinforcement layer 29, 39 as shown in Figs. 2 and 3 which
will resist
stretching and thereby inhibit bending.
It will be understood that up to some level of force applied by wind in the
direction 43, the shingle tab portion 44 will bend within its elastic limit in
accordance
with Hook's law. In this regard, any given weight of shingle, under any
particular
conditions, will have its own modulus of elasticity, which is a measure of the
stiffness or
rigidity of the shingle, and within which the shingle will return to its
original, flat
condition when the force of wind is removed.
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With reference to Fig. 4A, the vertical section of a shingle 41, as applied to
a roof
40 is illustrated, with the roof 40 being similar to that set forth above and
the attendant
description thereof. It will be seen that the reinforcement material 46,
underlying the
shingle 41, is engaged by the nail or other fastener 42 that is applied
through the nailing
zone of the shingle 41, with the shank 49 of the fastener 42 being in secure
engagement
within the roof 40, and passing through the reinforcement material 46. Thus,
especially
when the reinforcement material 46 is a scrim, a fabric, or any other material
that would
tend to resist tearing, the fasteners 42 holding shingles on a roof 40, of the
steepness
shown, or even a steeper roof, would tend to resist movement of the shingle 41
under
conditions of intense heat, and perhaps being walked upon by a worker, from
tending to
become disengaged from the roof, because the fasteners catch in the
reinforcement
material 46, and resist shingle 41 movement, for example from sliding down
along the
roof in the direction of the arrow 48.
Reference will now be made to the graphs of Figs. 5-8, for representative
benefits
achieved by using a scrim applied to shingles in the manner discussed above,
for various
weights of shingles having difference mats, and under the same temperature
conditions,
for comparison purposes.
With reference to Fig. 5, it will be seen that a shingle version is identified
as
version 3, with its control identified as version 3C, each being a 2501b.
shingle, in weight
per square (1 square equals enough shingles to cover 100 ft2 of roof) and with
2.51b. mat.
(in weight per 100 square feet of mat). In each case, the samples were tested
at 30 F.
The ordinate or vertical measure in the graph is the percent of the applied
force or load
that is absorbed by the shingle at a given degree of angular bend, as shown in
degrees on
the abscissa or horizontal line of the chart, under a fixed torque applied to
the shingle tab
portion, of 6.0 inch-lbs. It will be seen that for the control shingle of Fig.
5, failure, or
inelastic bending to the point that the shingle does not return to its
original, flat condition
when the force of wind is removed, occurred at about 40 of angular bend, with
failure
being defined as a crack or permanent bend as distinguished from a bend within
the
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elastic limit. However, for the shingle having a scrim of 21/2 inches in
width, as shown in
Fig. 2, it will be seen that in Fig. 5 that shingle with the scrim remained
within its elastic
limit up to about 600 of angular bend, prior to failure. It will thus be seen
that the
specimen graphed in Fig. 5 having a scrim applied thereto absorbed about 75%
of the
torque load applied thereto, for a bend of the tab portion of the shingle of
about 60 ,
before failure.
Referring now to Fig. 6, wherein a version 4 was matched against a control
version 4C, for a 2351b. weight of shingle having a 2.61b. mat, again at 30 ,
the control
version absorbed about 60% of the torque that was applied, up to about 40 of
angular
bend, whereas the specimen graphed in Fig. 6 having a 21/2 inch wide scrim
applied
thereto absorbed about 77% of the applied torque load, when subjected to a
bend of 60 ,
before failure.
Referring now to Fig. 7, wherein yet another shingle 5 was tested against a
control
shingle 5C, with the shingle graphed in Fig. 7, like that of Fig. 6, also
being a 2351b.
weight per stack, but having a 2.51b. mat, and likewise having a 21/2 inch
wide scrim, it
will be seen that, whereas the control version absorbed only about 55% of the
applied
torque at about a 40 bend, the version with the scrim applied thereto
absorbed about
70% of the applied load, when bent about 70 . Thus, the effect of a slightly
thinner mat
was noted for a shingle with scrim applied thereto.
With reference now to Fig. 8, it will be seen that shingle versions 6 and
control
shingles 6C were also shown as comprising a 2351b. shingle by weight, and a
21/21b. mat,
but wherein, unlike the similar specimen indicated for Fig. 7, the specimen
graphed in
Fig. 8 had a 6 inch wide scrim applied thereto. It will be seen that the
control version of
Fig. 8 tested similarly to that of the control version of Fig. 7, and that the
version with the
6 inch scrim applied thereto likewise tested similarly to that of the scrim-
applied version
of Fig. 7.
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It has thus been found that the bending tests, performed with a Tinius-Olsen
Flexibility Tester to apply the force bending the shingle tab portions 44 in
the direction of
the arrow 45 of Fig. 4 all show that the specimens with scrim reinforcement
embedded on
their rear sides exhibit improved resistance to failure upon bending, and thus
are capable
of maintaining and carrying applied stress due to bending to much higher
degrees than
shingle specimens without the scrim. Thus, shingles with the scrim applied
thereto in
accordance with this invention provide improved resistance to damage due to
wind uplift.
Nail pull tests were run on a plurality of shingles, with and without
reinforcement
layers. The tests were run on 4 inch by 4 inch specimens, placed over a plate
having a
21/2 inch center hole, with the nail being driven through the shingle, so as
to place the nail
at the center of the 21/2 inch hole, which in turn is at the center of the 4
inch by 4 inch
plate, and with the nail then being pulled upwardly to determine the strength
of the
shingle in resisting failure or tearing against the force of the nail pull.
This is a
standardized test for shingles pursuant to ASTM.
First, ten specimens of control shingles were tested, having no reinforcement
layer on their rear surface. The resistance strength of the control samples
prior to failure,
averaged 29.69 lb. 3.78 lb. deviation over the ten shingles tested.
Next, ten specimens of the same type of shingle as the control shingle were
tested,
but which deviated from the control shingle, in that they had a 17 gram
polyester mat
reinforcement layer on their rear surfaces. The resistance strength of these
specimen
resisting the nail pull, prior to failure, averaged 33.27 lb. 3.52 lb.
deviation over the ten
specimens tested.
Then, ten specimens of shingle constructed the same as the control shingles,
but
different from the control shingles in that they each had a reinforcement
layer on the rear
surface, of 30 gram polyester mat. The resistance strength, of these specimens
in
resisting the nail pull prior to failure averaged 36.96 lb. 3.98 lb.
deviation over the ten
specimens tested.
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Then. ten specimens of the same type of specimens as the control shingle were
tested, but wherein the reinforcement layer was a fiberglass scrim having nine
strands in
the vertical direction and nine strands in the horizontal direction per square
inch (9x9 per
in2). The ten specimens with the fiberglass scrim on the rear surface averaged
54.13 lb.
resistance to the nail pull test prior to failure, + 4.02 lb. deviation over
the ten specimens
tested.
These nail pull strength tests thus revealed that the fiberglass scrim as a
reinforcement layer provided the greatest resistance prior to failure,
although each of the
17 gram polyester mat and 30 gram polyester mat provided greater resistance
prior to
failure than the control specimens without any reinforcement layer.
It will thus be seen that, when nails or other fasteners are applied to the
shingle,
for fastening the shingle to a roof, they pass through the reinforcement
layer. This more
securely fastens the shingle to a roof, and is especially desirable when
applied to roofs
having steep slopes, in that it can sometimes occur on very hot sunny days, on
a steep
roof, perhaps with workmen walking on the roof, that the stress on the shingle
can cause
the shingle to tear above the fastening points and perhaps become dislodged
from the
roof. By fastening the shingle to a roof through the reinforcement zone in
such a
situation, the fasteners are more prone to maintain the shingle adhered to the
roof. This
can be especially so if the reinforcement material that is applied to the rear
of the roof
comprises a scrim of crossing strands, a fabric, or other material that is
resistant to
tearing.
It will be apparent from the forgoing that various modifications may be made
in the
details of construction, as well as with the use of shingles of this
invention, all within the scope
of the invention as defined in the appended claims.
